Efficacy comparison between cryoablation and radiofrequency ablation for patients with cavotricuspid valve isthmus dependent atrial flutter: a meta-analysis

PubMed Central

Chen, Yi-He; Lin, Hui; Xie, Cheng-Long; Zhang, Xiao-Ting; Li, Yi-Gang

2015-01-01

We perform this meta-analysis to compare the efficacy and safety of cryoablation versus radiofrequency ablation for patients with cavotricuspid valve isthmus dependent atrial flutter. By searching EMBASE, MEDLINE, PubMed and Cochrane electronic databases from March 1986 to September 2014, 7 randomized clinical trials were included. Acute (risk ratio[RR]: 0.93; P = 0.14) and long-term (RR: 0.94; P = 0.08) success rate were slightly lower in cryoablation group than in radiofrequency ablation group, but the difference was not statistically significant. Additionally, the fluoroscopy time was nonsignificantly reduced (weighted mean difference[WMD]: −2.83; P = 0.29), whereas procedure time was significantly longer (WMD: 25.95; P = 0.01) in cryoablation group compared with radiofrequency ablation group. Furthermore, Pain perception during the catheter ablation was substantially less in cryoabaltion group than in radiofrequency ablation group (standardized mean difference[SMD]: −2.36; P < 0.00001). Thus, our meta-analysis demonstrated that cryoablation and radiofrequency ablation produce comparable acute and long-term success rate for patients with cavotricuspid valve isthmus dependent atrial flutter. Meanwhile, cryoablation ablation tends to reduce the fluoroscopy time and significantly reduce pain perception in cost of significantly prolonged procedure time. PMID:26039980

Naltrexone versus acamprosate in the treatment of alcohol dependence: A multi-centre, randomized, double-blind, placebo-controlled trial.

PubMed

Morley, Kirsten C; Teesson, Maree; Reid, Sophie C; Sannibale, Claudia; Thomson, Clare; Phung, Nghi; Weltman, Martin; Bell, James R; Richardson, Kylie; Haber, Paul S

2006-10-01

To compare the efficacy of acamprosate and naltrexone in the treatment of alcohol dependence. A double-blind, placebo-controlled trial. Three treatment centres in Australia. A total of 169 alcohol dependent subjects were given naltrexone (50 mg/day), acamprosate (1998 mg/day) or placebo for 12 weeks. All subjects were offered manualized compliance therapy, a brief intervention that targets problems that may affect treatment compliance such as ambivalence and misperceptions about medication. Time to the first drink, time to first relapse, drinks per drinking day and cumulative abstinence. In intention-to-treat analyses, there were no differences between groups on outcome measures of drinking, craving or biochemical markers. Similarly, analyses of the 94 subjects that completed the study in full and demonstrated 80% compliance, revealed no significant treatment effects. Differential treatment effects were identified after stratification according to scores on the Alcohol Dependence Scale (ADS) and Depression Anxiety and Stress Scale (DASS). A significant beneficial treatment effect on time to first relapse was revealed for subjects with 'no depression' allocated to naltrexone (n = 56; P < 0.01). In addition, a significant beneficial treatment effect was revealed in subjects with 'low dependence' allocated to naltrexone (n = 34; P < 0.05). The results of this study support the efficacy of naltrexone in the relapse prevention of alcoholism amongst those with low levels of clinical depression and alcohol dependence severity. No effect of acamprosate was found in our sample.

Two-stream instability with time-dependent drift velocity

DOE PAGES

Qin, Hong; Davidson, Ronald C.

2014-06-26

The classical two-stream instability driven by a constant relative drift velocity between two plasma components is extended to the case with time-dependent drift velocity. A solution method is developed to rigorously define and calculate the instability growth rate for linear perturbations relative to the time-dependent unperturbed two-stream motions. The stability diagrams for the oscillating two-stream instability are presented over a large region of parameter space. It is shown that the growth rate for the classical two-stream instability can be significantly reduced by adding an oscillatory component to the relative drift velocity.

Does whole blood coagulation analysis reflect developmental haemostasis?

PubMed

Ravn, Hanne Berg; Andreasen, Jo Bønding; Hvas, Anne-Mette

2017-04-01

: Developmental haemostasis has been well documented over the last 3 decades and age-dependent reference ranges have been reported for a number of plasmatic coagulation parameters. With the increasing use of whole blood point-of-care tests like rotational thromboelastometry (ROTEM) and platelet function tests, an evaluation of age-dependent changes is warranted for these tests as well. We obtained blood samples from 149 children, aged 1 day to 5.9 years, and analysed conventional plasmatic coagulation tests, including activated partial prothrombin time, prothrombin time, and fibrinogen (functional). Whole blood samples were analysed using ROTEM to assess overall coagulation capacity and Multiplate analyzer to evaluate platelet aggregation. Age-dependent changes were analysed for all variables. We found age-dependent differences in all conventional coagulation tests (all P values < 0.05), but there was no sign of developmental changes in whole blood coagulation assessment when applying ROTEM, apart from clotting time in the EXTEM assay (P < 0.03). Despite marked differences in mean platelet aggregation between age groups, data did not reach statistical significance. Citrate-anticoagulated blood showed significantly reduced platelet aggregation compared with blood anticoagulated with heparin or hirudin (all P values < 0.003). We confirmed previous developmental changes in conventional plasmatic coagulation test. However, these age-dependent changes were not displayed in whole blood monitoring using ROTEM or Multiplate analyzer. Type of anticoagulant had a significant influence on platelet aggregation across all age groups.

Change in Care Dependency of Stroke Patients: A Longitudinal and Multicenter Study.

PubMed

Nursiswati, Nursiswati; Halfens, Ruud J G; Lohrmann, Christa

2017-06-01

The study was conducted to investigate the change of care dependency in stroke patients from inpatient wards and outpatient units in Indonesia. This study is longitudinal and multicentered. One hundred and nine patients were included from four hospitals on the island of Java. Care dependency was assessed using the Indonesian version of the 15-item Care Dependency Scale (CDS) at five points in time: at inpatient wards for admission and discharge and at outpatient units after discharge in the 1st week, the 5th week, and the 13th week. Most of the patients were male (65.1%), and diagnosed with ischemic stroke (71.5%). The results showed that care dependency in stroke patients decreased significantly from admission to discharge, as well as from the 5th to the 13th week as measured by the CDS. At admission, 23.0% of the patients were completely dependent on care, and at the 13th week about 1.0% were. Patients' care dependency decreased significantly in all care dependency items of the CDS in the inpatient ward, but five care dependency items of the CDS did not significantly decrease in the outpatient unit. Based on the findings of this study, we recommend that hospital-based and community-based services should include continual care dependence monitoring using this comprehensive instrument. Care dependency is subject to change over time, therefore nurses have to plan and tailor adequate nursing care measures to patient needs in the different stages, especially with respect to the aspect of mobility. Copyright © 2017. Published by Elsevier B.V.

A better understanding of long-range temporal dependence of traffic flow time series

NASA Astrophysics Data System (ADS)

Feng, Shuo; Wang, Xingmin; Sun, Haowei; Zhang, Yi; Li, Li

2018-02-01

Long-range temporal dependence is an important research perspective for modelling of traffic flow time series. Various methods have been proposed to depict the long-range temporal dependence, including autocorrelation function analysis, spectral analysis and fractal analysis. However, few researches have studied the daily temporal dependence (i.e. the similarity between different daily traffic flow time series), which can help us better understand the long-range temporal dependence, such as the origin of crossover phenomenon. Moreover, considering both types of dependence contributes to establishing more accurate model and depicting the properties of traffic flow time series. In this paper, we study the properties of daily temporal dependence by simple average method and Principal Component Analysis (PCA) based method. Meanwhile, we also study the long-range temporal dependence by Detrended Fluctuation Analysis (DFA) and Multifractal Detrended Fluctuation Analysis (MFDFA). The results show that both the daily and long-range temporal dependence exert considerable influence on the traffic flow series. The DFA results reveal that the daily temporal dependence creates crossover phenomenon when estimating the Hurst exponent which depicts the long-range temporal dependence. Furthermore, through the comparison of the DFA test, PCA-based method turns out to be a better method to extract the daily temporal dependence especially when the difference between days is significant.

Efficiency and cross-correlation in equity market during global financial crisis: Evidence from China

NASA Astrophysics Data System (ADS)

Ma, Pengcheng; Li, Daye; Li, Shuo

2016-02-01

Using one minute high-frequency data of the Shanghai Composite Index (SHCI) and the Shenzhen Composite Index (SZCI) (2007-2008), we employ the detrended fluctuation analysis (DFA) and the detrended cross correlation analysis (DCCA) with rolling window approach to observe the evolution of market efficiency and cross-correlation in pre-crisis and crisis period. Considering the fat-tail distribution of return time series, statistical test based on shuffling method is conducted to verify the null hypothesis of no long-term dependence. Our empirical research displays three main findings. First Shanghai equity market efficiency deteriorated while Shenzhen equity market efficiency improved with the advent of financial crisis. Second the highly positive dependence between SHCI and SZCI varies with time scale. Third financial crisis saw a significant increase of dependence between SHCI and SZCI at shorter time scales but a lack of significant change at longer time scales, providing evidence of contagion and absence of interdependence during crisis.

A Study of Time-dependent and Anisotropic Effects on the Deformation Response of Two Flywheel Designs

NASA Technical Reports Server (NTRS)

Saleeb, Atef F.; Arnold, Steven M.; Al-Zoubi, Nasser R.

2003-01-01

The influence of material time dependency and anisotropy in the context of two specific flywheel designs-preload and multi-directional composite (MDC)--is investigated. In particular, we focus on the following aspects: 1) geometric constraints, 2) material constraints, 3) loading type, and 4) the fundamental character of the time-dependent response, i.e., reversible or irreversible. The bulk of the results presented were obtained using a composite (PMC IM7/8552 at 135 C) material system. The material was characterized using a general multimechanism hereditary (viscoelastoplastic) model. As a general conclusion, the results have clearly shown that both the preload and the MDC rotor designs are significantly affected by time-dependent material behavior, which may impact the state of rotor balance and potentially reduce its operating life. In view of the results of the parametric studies and predictions made in the present study, the need for actual experimentation focusing on the time-dependent behavior of full-scale flywheel rotors is self-evident.

Spin Flips versus Spin Transport in Nonthermal Electrons Excited by Ultrashort Optical Pulses in Transition Metals

NASA Astrophysics Data System (ADS)

Shokeen, V.; Sanchez Piaia, M.; Bigot, J.-Y.; Müller, T.; Elliott, P.; Dewhurst, J. K.; Sharma, S.; Gross, E. K. U.

2017-09-01

A joint theoretical and experimental investigation is performed to understand the underlying physics of laser-induced demagnetization in Ni and Co films with varying thicknesses excited by 10 fs optical pulses. Experimentally, the dynamics of spins is studied by determining the time-dependent amplitude of the Voigt vector, retrieved from a full set of magnetic and nonmagnetic quantities performed on both sides of films, with absolute time reference. Theoretically, ab initio calculations are performed using time-dependent density functional theory. Overall, we demonstrate that spin-orbit induced spin flips are the most significant contributors with superdiffusive spin transport, which assumes only that the transport of majority spins without spin flips induced by scattering does not apply in Ni. In Co it plays a significant role during the first ˜20 fs only. Our study highlights the material dependent nature of the demagnetization during the process of thermalization of nonequilibrium spins.

Automatic mechanisms for measuring subjective unit of discomfort.

PubMed

Hartanto, D W I; Kang, Ni; Brinkman, Willem-Paul; Kampmann, Isabel L; Morina, Nexhmedin; Emmelkamp, Paul G M; Neerincx, Mark A

2012-01-01

Current practice in Virtual Reality Exposure Therapy (VRET) is that therapists ask patients about their anxiety level by means of the Subjective Unit of Discomfort (SUD) scale. With an aim of developing a home-based VRET system, this measurement ideally should be done using speech technology. In a VRET system for social phobia with scripted avatar-patient dialogues, the timing of asking patients to give their SUD score becomes relevant. This study examined three timing mechanisms: (1) dialogue dependent (i.e. naturally in the flow of the dialogue); (2) speech dependent (i.e. when both patient and avatar are silent); and (3) context independent (i.e. randomly). Results of an experiment with non-patients (n = 24) showed a significant effect for the timing mechanisms on the perceived dialogue flow, user preference, reported presence and user dialog replies. Overall, dialogue dependent timing mechanism seems superior followed by the speech dependent and context independent timing mechanism.

The Well-Being of Australian Service Mothers.

PubMed

Davy, Carol P; Lorimer, Michelle; McFarlane, Alexander; Hodson, Stephanie; Crompvoets, Samantha; Lawrence-Wood, Ellie; Neuhaus, Susan J

2015-01-01

In recent years servicewomen with dependent children have for the first time in history been deployed into conflict zones in support of Australian Defence Force operations. This represents a significant social change, and the implications of deployment on the health of these service mothers are not fully understood. Data from women who participated in the Middle East Area of Operations Census study were analyzed to compare the psychological and physical symptoms reported by service mothers with service women who had no dependent children at the time of deploying to Afghanistan and/or Iraq. Of the 921 women who were included in this analysis, 235 had dependent children and 686 had no dependent children (comparison group). Service mothers were significantly older and were more likely to have served in the Air Force than women in the comparison group. Findings demonstrate that serving mothers were not at any significantly higher risk of psychological distress, post-traumatic stress symptoms, alcohol misuse, or reporting of somatic symptoms, than women who had no dependent children. A number of possible explanations for these findings are discussed, including the healthy soldier/mother effect, support from partners and extended family members, and collegial networks.

A time-dependent probabilistic seismic-hazard model for California

USGS Publications Warehouse

Cramer, C.H.; Petersen, M.D.; Cao, T.; Toppozada, Tousson R.; Reichle, M.

2000-01-01

For the purpose of sensitivity testing and illuminating nonconsensus components of time-dependent models, the California Department of Conservation, Division of Mines and Geology (CDMG) has assembled a time-dependent version of its statewide probabilistic seismic hazard (PSH) model for California. The model incorporates available consensus information from within the earth-science community, except for a few faults or fault segments where consensus information is not available. For these latter faults, published information has been incorporated into the model. As in the 1996 CDMG/U.S. Geological Survey (USGS) model, the time-dependent models incorporate three multisegment ruptures: a 1906, an 1857, and a southern San Andreas earthquake. Sensitivity tests are presented to show the effect on hazard and expected damage estimates of (1) intrinsic (aleatory) sigma, (2) multisegment (cascade) vs. independent segment (no cascade) ruptures, and (3) time-dependence vs. time-independence. Results indicate that (1) differences in hazard and expected damage estimates between time-dependent and independent models increase with decreasing intrinsic sigma, (2) differences in hazard and expected damage estimates between full cascading and not cascading are insensitive to intrinsic sigma, (3) differences in hazard increase with increasing return period (decreasing probability of occurrence), and (4) differences in moment-rate budgets increase with decreasing intrinsic sigma and with the degree of cascading, but are within the expected uncertainty in PSH time-dependent modeling and do not always significantly affect hazard and expected damage estimates.

Time-Dependent Behavior of Reinforced Polymer Concrete Columns under Eccentric Axial Loading

PubMed Central

Berardi, Valentino Paolo; Mancusi, Geminiano

2012-01-01

Polymer concretes (PCs) represent a promising alternative to traditional cementitious materials in the field of new construction. In fact, PCs exhibit high compressive strength and ultimate compressive strain values, as well as good chemical resistance. Within the context of these benefits, this paper presents a study on the time-dependent behavior of polymer concrete columns reinforced with different bar types using a mechanical model recently developed by the authors. Balanced internal reinforcements are considered (i.e., two bars at both the top and bottom of the cross-section). The investigation highlights relevant stress and strain variations over time and, consequently, the emergence of a significant decrease in concrete’s stiffness and strength over time. Therefore, the results indicate that deferred effects due to viscous flow may significantly affect the reliability of reinforced polymer concrete elements over time.

Integrating stochastic time-dependent travel speed in solution methods for the dynamic dial-a-ride problem

PubMed Central

Schilde, M.; Doerner, K.F.; Hartl, R.F.

2014-01-01

In urban areas, logistic transportation operations often run into problems because travel speeds change, depending on the current traffic situation. If not accounted for, time-dependent and stochastic travel speeds frequently lead to missed time windows and thus poorer service. Especially in the case of passenger transportation, it often leads to excessive passenger ride times as well. Therefore, time-dependent and stochastic influences on travel speeds are relevant for finding feasible and reliable solutions. This study considers the effect of exploiting statistical information available about historical accidents, using stochastic solution approaches for the dynamic dial-a-ride problem (dynamic DARP). The authors propose two pairs of metaheuristic solution approaches, each consisting of a deterministic method (average time-dependent travel speeds for planning) and its corresponding stochastic version (exploiting stochastic information while planning). The results, using test instances with up to 762 requests based on a real-world road network, show that in certain conditions, exploiting stochastic information about travel speeds leads to significant improvements over deterministic approaches. PMID:25844013

THE EFFECT OF A DYNAMIC INNER HELIOSHEATH THICKNESS ON COSMIC-RAY MODULATION

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

Manuel, R.; Ferreira, S. E. S.; Potgieter, M. S., E-mail: rexmanuel@live.com

2015-02-01

The time-dependent modulation of galactic cosmic rays in the heliosphere is studied over different polarity cycles by computing 2.5 GV proton intensities using a two-dimensional, time-dependent modulation model. By incorporating recent theoretical advances in the relevant transport parameters in the model, we showed in previous work that this approach gave realistic computed intensities over a solar cycle. New in this work is that a time dependence of the solar wind termination shock (TS) position is implemented in our model to study the effect of a dynamic inner heliosheath thickness (the region between the TS and heliopause) on the solar modulationmore » of galactic cosmic rays. The study reveals that changes in the inner heliosheath thickness, arising from a time-dependent shock position, does affect cosmic-ray intensities everywhere in the heliosphere over a solar cycle, with the smallest effect in the innermost heliosphere. A time-dependent TS position causes a phase difference between the solar activity periods and the corresponding intensity periods. The maximum intensities in response to a solar minimum activity period are found to be dependent on the time-dependent TS profile. It is found that changing the width of the inner heliosheath with time over a solar cycle can shift the time of when the maximum or minimum cosmic-ray intensities occur at various distances throughout the heliosphere, but more significantly in the outer heliosphere. The time-dependent extent of the inner heliosheath, as affected by solar activity conditions, is thus an additional time-dependent factor to be considered in the long-term modulation of cosmic rays.« less

Rational design of an improved tissue-engineered vascular graft: determining the optimal cell dose and incubation time.

PubMed

Lee, Yong-Ung; Mahler, Nathan; Best, Cameron A; Tara, Shuhei; Sugiura, Tadahisa; Lee, Avione Y; Yi, Tai; Hibino, Narutoshi; Shinoka, Toshiharu; Breuer, Christopher

2016-03-01

We investigated the effect of cell seeding dose and incubation time on tissue-engineered vascular graft (TEVG) patency. Various doses of bone marrow-derived mononuclear cells (BM-MNCs) were seeded onto TEVGs, incubated for 0 or 12 h, and implanted in C57BL/6 mice. Different doses of human BM-MNCs were seeded onto TEVGs and measured for cell attachment. The incubation time showed no significant effect on TEVG patency. However, TEVG patency was significantly increased in a dose-dependent manner. In the human graft, more bone marrow used for seeding resulted in increased cell attachment in a dose-dependent manner. Increasing the BM-MNC dose and reducing incubation time is a viable strategy for improving the performance and utility of the graft.

Randomized open-label trial of baclofen for relapse prevention in alcohol dependence.

PubMed

Gupta, Manushree; Verma, Pankaj; Rastogi, Rajesh; Arora, Sheetal; Elwadhi, Deeksha

2017-05-01

Alcohol dependence is a progressive chronic disorder characterized by narrowing of the drinking repertoire, salience of drinking, tolerance and withdrawal phenomenon, compulsion to drink, and frequent relapses. Baclofen has been shown to promote abstinence, to reduce craving, and to reduce anxiety in alcohol-dependent individuals, and it promises to be a useful agent, although clinical data are limited at present. The current study aimed to test the utility of baclofen, a GABA agonist, in improving the relapse rates in alcohol-dependent subjects. A total of 122 alcohol-dependent subjects were randomized into two groups. Groups were administered baclofen (30 mg/day) or benfothiamine (a nutritional supplement) using an open label design. Both groups received brief motivational intervention. Subjects were assessed at 0, 2, 4, 8, and 12 weeks for the primary outcome measures: time to first relapse, heavy drinking days, cumulative abstinence duration, and craving (measured by the Obsessive Compulsive Drinking Scale (OCDS)). Seventy-two participants received baclofen, and 50 received benfothiamine. Participants receiving baclofen remained abstinent for significantly more days than the benfothiamine group (p < 0.05). The percentage of heavy drinking days was significantly lower in the baclofen group (p = 0.001). Craving and anxiety scores (Hamilton Anxiety Rating Scale) were also significantly decreased in the baclofen group relative to the control group (p = 0.001). Time to first relapse was similar in both groups. In this open-label trial, alcohol-dependent participants receiving baclofen showed significant improvements in drinking outcomes compared with participants receiving benfothiamine. This study provides further evidence that baclofen is useful for the treatment of alcohol dependence.

Factors affecting medication-order processing time.

PubMed

Beaman, M A; Kotzan, J A

1982-11-01

The factors affecting medication-order processing time at one hospital were studied. The order processing time was determined by directly observing the time to process randomly selected new drug orders on all three work shifts during two one-week periods. An order could list more than one drug for an individual patient. The observer recorded the nature, location, and cost of the drugs ordered, as well as the time to process the order. The time and type of interruptions also were noted. The time to process a drug order was classified as six dependent variables: (1) total time, (2) work time, (3) check time, (4) waiting time I--time from arrival on the dumbwaiter until work was initiated, (5) waiting time II--time between completion of the work and initiation of checking, and (6) waiting time III--time after the check was completed until the order left on the dumbwaiter. The significant predictors of each of the six dependent variables were determined using stepwise multiple regression. The total time to process a prescription order was 58.33 +/- 48.72 minutes; the urgency status of the order was the only significant determinant of total time. Urgency status also significantly predicted the three waiting-time variables. Interruptions and the number of drugs on the order were significant determinants of work time and check time. Each telephone interruption increased the work time by 1.72 minutes. While the results of this study cannot be generalized to other institutions, pharmacy managers can use the method of determining factors that affect medication-order processing time to identify problem areas in their institutions.

Limits on an energy dependence of the speed of light from a flare of the active galaxy PKS 2155-304.

PubMed

Aharonian, F; Akhperjanian, A G; Barres de Almeida, U; Bazer-Bachi, A R; Becherini, Y; Behera, B; Beilicke, M; Benbow, W; Bernlöhr, K; Boisson, C; Bochow, A; Borrel, V; Braun, I; Brion, E; Brucker, J; Brun, P; Bühler, R; Bulik, T; Büsching, I; Boutelier, T; Carrigan, S; Chadwick, P M; Charbonnier, A; Chaves, R C G; Chounet, L-M; Clapson, A C; Coignet, G; Costamante, L; Dalton, M; Degrange, B; Deil, C; Dickinson, H J; Djannati-Ataï, A; Domainko, W; Drury, L O'C; Dubois, F; Dubus, G; Dyks, J; Egberts, K; Emmanoulopoulos, D; Espigat, P; Farnier, C; Feinstein, F; Fiasson, A; Förster, A; Fontaine, G; Füssling, M; Gabici, S; Gallant, Y A; Gérard, L; Giebels, B; Glicenstein, J F; Glück, B; Goret, P; Hadjichristidis, C; Hauser, D; Hauser, M; Heinz, S; Heinzelmann, G; Henri, G; Hermann, G; Hinton, J A; Hoffmann, A; Hofmann, W; Holleran, M; Hoppe, S; Horns, D; Jacholkowska, A; de Jager, O C; Jung, I; Katarzyński, K; Kaufmann, S; Kendziorra, E; Kerschhaggl, M; Khangulyan, D; Khélifi, B; Keogh, D; Komin, Nu; Kosack, K; Lamanna, G; Lenain, J-P; Lohse, T; Marandon, V; Martin, J M; Martineau-Huynh, O; Marcowith, A; Maurin, D; McComb, T J L; Medina, C; Moderski, R; Moulin, E; Naumann-Godo, M; de Naurois, M; Nedbal, D; Nekrassov, D; Niemiec, J; Nolan, S J; Ohm, S; Olive, J-F; de Oña Wilhelmi, E; Orford, K J; Osborne, J L; Ostrowski, M; Panter, M; Pedaletti, G; Pelletier, G; Petrucci, P-O; Pita, S; Pühlhofer, G; Punch, M; Quirrenbach, A; Raubenheimer, B C; Raue, M; Rayner, S M; Renaud, M; Rieger, F; Ripken, J; Rob, L; Rosier-Lees, S; Rowell, G; Rudak, B; Ruppel, J; Sahakian, V; Santangelo, A; Schlickeiser, R; Schöck, F M; Schröder, R; Schwanke, U; Schwarzburg, S; Schwemmer, S; Shalchi, A; Skilton, J L; Sol, H; Spangler, D; Stawarz, Ł; Steenkamp, R; Stegmann, C; Superina, G; Tam, P H; Tavernet, J-P; Terrier, R; Tibolla, O; van Eldik, C; Vasileiadis, G; Venter, C; Vialle, J P; Vincent, P; Vivier, M; Völk, H J; Volpe, F; Wagner, S J; Ward, M; Zdziarski, A A; Zech, A

2008-10-24

In the past few decades, several models have predicted an energy dependence of the speed of light in the context of quantum gravity. For cosmological sources such as active galaxies, this minuscule effect can add up to measurable photon-energy dependent time lags. In this Letter a search for such time lags during the High Energy Stereoscopic System observations of the exceptional very high energy flare of the active galaxy PKS 2155-304 on 28 July 2006 is presented. Since no significant time lag is found, lower limits on the energy scale of speed of light modifications are derived.

Time-dependent analysis of incidence, risk factors and clinical significance of pneumothorax after percutaneous lung biopsy.

PubMed

Lim, Woo Hyeon; Park, Chang Min; Yoon, Soon Ho; Lim, Hyun-Ju; Hwang, Eui Jin; Lee, Jong Hyuk; Goo, Jin Mo

2018-03-01

To evaluate the time-dependent incidence, risk factors and clinical significance of percutaneous lung biopsy (PLB)-related pneumothorax. From January 2012-November 2015, 3,251 patients underwent 3,354 cone-beam CT-guided PLBs for lung lesions. Cox, logistic and linear regression analyses were performed to identify time-dependent risk factors of PLB-related pneumothorax, risk factors of drainage catheter insertion and those of prolonged catheter placement, respectively. Pneumothorax occurred in 915/3,354 PLBs (27.3 %), with 230/915 (25.1 %) occurring during follow-ups. Risk factors for earlier occurrence of PLB-related pneumothorax include emphysema (HR=1.624), smaller target (HR=0.922), deeper location (HR=1.175) and longer puncture time (HR=1.036), while haemoptysis (HR=0.503) showed a protective effect against earlier development of pneumothorax. Seventy-five cases (8.2 %) underwent chest catheter placement. Mean duration of catheter placement was 3.2±2.0 days. Emphysema (odds ratio [OR]=2.400) and longer puncture time (OR=1.053) were assessed as significant risk factors for catheter insertion, and older age (parameter estimate=1.014) was a predictive factor for prolonged catheter placement. PLB-related pneumothorax occurred in 27.3 %, of which 25.1 % developed during follow-ups. Smaller target size, emphysema, deeply-located lesions were significant risk factors of PLB-related pneumothorax. Emphysema and older age were related to drainage catheter insertion and prolonged catheter placement, respectively. • One-fourth of percutaneous lung biopsy (PLB)-related pneumothorax occurs during follow-up. • Smaller, deeply-located target and emphysema lead to early occurrence of pneumothorax. • Emphysema is related to drainage catheter insertion for PLB-related pneumothorax. • Older age may lead to prolonged catheter placement for PLB-related pneumothorax. • Tailored management can be possible with time-dependent information of PLB-related pneumothorax.

Intra-oral administration of rebamipide liquid prevents tongue injuries induced by X-ray irradiation in rats.

PubMed

Nakashima, Takako; Uematsu, Naoya; Sakurai, Kazushi

2017-07-01

Oral mucositis is a common and serious side effect in patients who undergo cytotoxic cancer therapies. The purpose of this study was to investigate the preventive effects of rebamipide on radiation-induced glossitis model in rats. Glossitis was induced by a single dose of 15 Gy of X-rays to the snouts of rats (day 0). A novel form of rebamipide liquid comprising its submicronized crystals was administered intra-orally. The preventive effect of rebamipide on tongue injuries was macroscopically evaluated on day 7 following irradiation. The pretreatment period, dosing frequency, and dose dependency of rebamipide were examined. Two percent rebamipide liquid, administered six times a day for 14 days from day -7 to day 6, significantly decreased the ulcer-like area. However, no significant effect was observed when rebamipide was given either from day -4 or from day -1. Four or six times daily, 2% rebamipide liquid significantly inhibited the ulcer-like injury area ratio, but not when given twice daily. Rebamipide liquid, 1, 2, and 4% six times daily significantly reduced the area ratios of total injury and ulcer-like injury in a dose-dependent manner. Gene expression and protein levels of proinflammatory cytokines and chemokines were dramatically elevated in the irradiated tongues of control rats on day 7 without rebamipide liquid treatment. They were dose-dependently and significantly suppressed in rebamipide-treated groups. Intra-oral administration of rebamipide liquid prevented oral mucositis dose-dependently accompanied by the suppression of inflammatory expression in the radiation-induced rats' glossitis model.

Mechanical and time-dependent behavior of wood-plastic composites subjected to tension and compression

Treesearch

Scott E. Hamel; John C. Hermanson; Steven M. Cramer

2012-01-01

The thermoplastics within wood—plastic composites (WPCs) are known to experience significant time-dependent deformation or creep. In some formulations, creep deformation can be twice as much as the initial quasi-static strain in as little as 4 days. While extensive work has been done on the creep behavior of pure polymers, little information is available on the...

Statistical test for ΔρDCCA cross-correlation coefficient

NASA Astrophysics Data System (ADS)

Guedes, E. F.; Brito, A. A.; Oliveira Filho, F. M.; Fernandez, B. F.; de Castro, A. P. N.; da Silva Filho, A. M.; Zebende, G. F.

2018-07-01

In this paper we propose a new statistical test for ΔρDCCA, Detrended Cross-Correlation Coefficient Difference, a tool to measure contagion/interdependence effect in time series of size N at different time scale n. For this proposition we analyzed simulated and real time series. The results showed that the statistical significance of ΔρDCCA depends on the size N and the time scale n, and we can define a critical value for this dependency in 90%, 95%, and 99% of confidence level, as will be shown in this paper.

Time-dependent dielectric breakdown of plasma-exposed porous organosilicate glass

NASA Astrophysics Data System (ADS)

Nichols, M. T.; Sinha, H.; Wiltbank, C. A.; Antonelli, G. A.; Nishi, Y.; Shohet, J. L.

2012-03-01

Time-dependent dielectric breakdown (TDDB) is a major concern for low-k organosilicate dielectrics. To examine the effect of plasma exposure on TDDB degradation, time-to-breakdown measurements were made on porous SiCOH before and after exposure to plasma. A capillary-array window was used to separate charged particle and vacuum ultraviolet (VUV) photon bombardment. Samples exposed to VUV photons, and a combination of VUV photons and ion bombardment exhibited significant degradation in breakdown time. The samples exposed to VUV photons and ion bombardment showed more degradation in breakdown time in comparison to samples exposed to VUV photons alone.

Modeling the influence of preferential flow on the spatial variability and time-dependence of mineral weathering rates

DOE PAGES

Pandey, Sachin; Rajaram, Harihar

2016-12-05

Inferences of weathering rates from laboratory and field observations suggest significant scale and time-dependence. Preferential flow induced by heterogeneity (manifest as permeability variations or discrete fractures) has been suggested as one potential mechanism causing scale/time-dependence. In this paper, we present a quantitative evaluation of the influence of preferential flow on weathering rates using reactive transport modeling. Simulations were performed in discrete fracture networks (DFNs) and correlated random permeability fields (CRPFs), and compared to simulations in homogeneous permeability fields. The simulations reveal spatial variability in the weathering rate, multidimensional distribution of reactions zones, and the formation of rough weathering interfaces andmore » corestones due to preferential flow. In the homogeneous fields and CRPFs, the domain-averaged weathering rate is initially constant as long as the weathering front is contained within the domain, reflecting equilibrium-controlled behavior. The behavior in the CRPFs was influenced by macrodispersion, with more spread-out weathering profiles, an earlier departure from the initial constant rate and longer persistence of weathering. DFN simulations exhibited a sustained time-dependence resulting from the formation of diffusion-controlled weathering fronts in matrix blocks, which is consistent with the shrinking core mechanism. A significant decrease in the domain-averaged weathering rate is evident despite high remaining mineral volume fractions, but the decline does not follow a math formula dependence, characteristic of diffusion, due to network scale effects and advection-controlled behavior near the inflow boundary. Finally, the DFN simulations also reveal relatively constant horizontally averaged weathering rates over a significant depth range, challenging the very notion of a weathering front.« less

Modeling the influence of preferential flow on the spatial variability and time-dependence of mineral weathering rates

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

Pandey, Sachin; Rajaram, Harihar

Inferences of weathering rates from laboratory and field observations suggest significant scale and time-dependence. Preferential flow induced by heterogeneity (manifest as permeability variations or discrete fractures) has been suggested as one potential mechanism causing scale/time-dependence. In this paper, we present a quantitative evaluation of the influence of preferential flow on weathering rates using reactive transport modeling. Simulations were performed in discrete fracture networks (DFNs) and correlated random permeability fields (CRPFs), and compared to simulations in homogeneous permeability fields. The simulations reveal spatial variability in the weathering rate, multidimensional distribution of reactions zones, and the formation of rough weathering interfaces andmore » corestones due to preferential flow. In the homogeneous fields and CRPFs, the domain-averaged weathering rate is initially constant as long as the weathering front is contained within the domain, reflecting equilibrium-controlled behavior. The behavior in the CRPFs was influenced by macrodispersion, with more spread-out weathering profiles, an earlier departure from the initial constant rate and longer persistence of weathering. DFN simulations exhibited a sustained time-dependence resulting from the formation of diffusion-controlled weathering fronts in matrix blocks, which is consistent with the shrinking core mechanism. A significant decrease in the domain-averaged weathering rate is evident despite high remaining mineral volume fractions, but the decline does not follow a math formula dependence, characteristic of diffusion, due to network scale effects and advection-controlled behavior near the inflow boundary. Finally, the DFN simulations also reveal relatively constant horizontally averaged weathering rates over a significant depth range, challenging the very notion of a weathering front.« less

[Correlation coefficient-based classification method of hydrological dependence variability: With auto-regression model as example].

PubMed

Zhao, Yu Xi; Xie, Ping; Sang, Yan Fang; Wu, Zi Yi

2018-04-01

Hydrological process evaluation is temporal dependent. Hydrological time series including dependence components do not meet the data consistency assumption for hydrological computation. Both of those factors cause great difficulty for water researches. Given the existence of hydrological dependence variability, we proposed a correlationcoefficient-based method for significance evaluation of hydrological dependence based on auto-regression model. By calculating the correlation coefficient between the original series and its dependence component and selecting reasonable thresholds of correlation coefficient, this method divided significance degree of dependence into no variability, weak variability, mid variability, strong variability, and drastic variability. By deducing the relationship between correlation coefficient and auto-correlation coefficient in each order of series, we found that the correlation coefficient was mainly determined by the magnitude of auto-correlation coefficient from the 1 order to p order, which clarified the theoretical basis of this method. With the first-order and second-order auto-regression models as examples, the reasonability of the deduced formula was verified through Monte-Carlo experiments to classify the relationship between correlation coefficient and auto-correlation coefficient. This method was used to analyze three observed hydrological time series. The results indicated the coexistence of stochastic and dependence characteristics in hydrological process.

Bayesian Inference for Time Trends in Parameter Values using Weighted Evidence Sets

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

D. L. Kelly; A. Malkhasyan

2010-09-01

There is a nearly ubiquitous assumption in PSA that parameter values are at least piecewise-constant in time. As a result, Bayesian inference tends to incorporate many years of plant operation, over which there have been significant changes in plant operational and maintenance practices, plant management, etc. These changes can cause significant changes in parameter values over time; however, failure to perform Bayesian inference in the proper time-dependent framework can mask these changes. Failure to question the assumption of constant parameter values, and failure to perform Bayesian inference in the proper time-dependent framework were noted as important issues in NUREG/CR-6813, performedmore » for the U. S. Nuclear Regulatory Commission’s Advisory Committee on Reactor Safeguards in 2003. That report noted that “in-dustry lacks tools to perform time-trend analysis with Bayesian updating.” This paper describes an applica-tion of time-dependent Bayesian inference methods developed for the European Commission Ageing PSA Network. These methods utilize open-source software, implementing Markov chain Monte Carlo sampling. The paper also illustrates an approach to incorporating multiple sources of data via applicability weighting factors that address differences in key influences, such as vendor, component boundaries, conditions of the operating environment, etc.« less

Bayesian Inference for Time Trends in Parameter Values: Case Study for the Ageing PSA Network of the European Commission

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

Dana L. Kelly; Albert Malkhasyan

2010-06-01

There is a nearly ubiquitous assumption in PSA that parameter values are at least piecewise-constant in time. As a result, Bayesian inference tends to incorporate many years of plant operation, over which there have been significant changes in plant operational and maintenance practices, plant management, etc. These changes can cause significant changes in parameter values over time; however, failure to perform Bayesian inference in the proper time-dependent framework can mask these changes. Failure to question the assumption of constant parameter values, and failure to perform Bayesian inference in the proper time-dependent framework were noted as important issues in NUREG/CR-6813, performedmore » for the U. S. Nuclear Regulatory Commission’s Advisory Committee on Reactor Safeguards in 2003. That report noted that “industry lacks tools to perform time-trend analysis with Bayesian updating.” This paper describes an application of time-dependent Bayesian inference methods developed for the European Commission Ageing PSA Network. These methods utilize open-source software, implementing Markov chain Monte Carlo sampling. The paper also illustrates the development of a generic prior distribution, which incorporates multiple sources of generic data via weighting factors that address differences in key influences, such as vendor, component boundaries, conditions of the operating environment, etc.« less

Use-dependent inhibition of Na+ currents by benzocaine homologs.

PubMed Central

Quan, C; Mok, W M; Wang, G K

1996-01-01

Most local anesthetics (LAs) elicit use-dependent inhibition of Na+ currents when excitable membranes are stimulated repetitively. One exception to this rule is benzocaine, a neutral LA that fails to produce appreciable use-dependent inhibition. In this study, we have examined the use-dependent phenomenon of three benzocaine homologs: ethyl 4-diethylaminobenzoate, ethyl 4-ethoxybenzoate, and ethyl 4-hydroxybenzoate. Ethyl 4-hydroxybenzoate at 1 mM, like benzocaine, elicited little use-dependent inhibition of Na+ currents, whereas ethyl 4-diethylaminobenzoate at 0.15 mM and ethyl 4-ethoxybenzoate at 0.5 mM elicited substantial use-dependent inhibition--up to 55% of peak Na+ currents were inhibited by repetitive depolarizations at 5 Hz. Each of these compounds produced significant tonic block of Na+ currents at rest and shifted the steady-state inactivation curve (h infinity) toward the hyperpolarizing direction. Kinetic analyses showed that the decaying phase of Na+ currents during a depolarizing pulse was significantly accelerated by all drugs, thus suggesting that these drugs also block the activated channel. The recovery time course for the use-dependent inhibition of Na+ currents was relatively slow, with time constants of 6.8 and 4.4 s for ethyl 4-diethylaminobenzoate and ethyl 4-ethoxybenzoate, respectively. We conclude that benzocaine and 4-hydroxybenzoate interact with the open and inactivated channels during repetitive pulses, but during the interpulse the complex dissociates too fast to accumulate sufficient use-dependent block of Na+ currents. In contrast, ethyl 4-diethylaminobenzoate and ethyl 4-ethoxybenzoate dissociate slowly from their binding site and consequently elicit significant use-dependent block. A common LA binding site suffices to explain the presence and absence of use-dependent block by benzocaine homologs during repetitive pulses. PMID:8770198

Improving 24-Month Abstinence and Employment Outcomes for Substance-Dependent Women Receiving Temporary Assistance for Needy Families With Intensive Case Management

PubMed Central

Neighbors, Charles J.; Kuerbis, Alexis; Riordan, Annette; Blanchard, Kimberly A.; McVeigh, Katharine H.; Morgan, Thomas J.; McCrady, Barbara

2009-01-01

Objective. We examined abstinence rates among substance-dependent women receiving Temporary Assistance for Needy Families (TANF) in intensive case management (ICM) over 24 months and whether ICM yielded significantly better employment outcomes compared with a screen-and-refer program (i.e., usual care). Methods. Substance-dependent (n = 302) and non–substance dependent (n = 150) TANF applicants in Essex County, New Jersey, were recruited. We randomly assigned substance-dependent women to ICM or usual care. We interviewed all women at 3, 9, 15, and 24 months. Results. Abstinence rates were higher for the ICM group than for the usual care group through 24 months of follow-up (odds ratio [OR] = 2.11; 95% confidence interval [CI] = 1.36, 3.29). A statistically significant interaction between time and group on number of days employed indicated that the rate of improvement over time in employment was greater for the ICM group than for the usual care group (incidence rate ratio = 1.03; 95% CI = 1.02, 1.04). Additionally, there were greater odds of being employed full time for those in the ICM group (OR = 1.68; 95% CI = 1.12, 2.51). Conclusions. ICM is a promising intervention for managing substance dependence among women receiving TANF and for improving employment rates among this vulnerable population. PMID:19059855

Detecting PM2.5's Correlations between Neighboring Cities Using a Time-Lagged Cross-Correlation Coefficient.

PubMed

Wang, Fang; Wang, Lin; Chen, Yuming

2017-08-31

In order to investigate the time-dependent cross-correlations of fine particulate (PM2.5) series among neighboring cities in Northern China, in this paper, we propose a new cross-correlation coefficient, the time-lagged q-L dependent height crosscorrelation coefficient (denoted by p q (τ, L)), which incorporates the time-lag factor and the fluctuation amplitude information into the analogous height cross-correlation analysis coefficient. Numerical tests are performed to illustrate that the newly proposed coefficient ρ q (τ, L) can be used to detect cross-correlations between two series with time lags and to identify different range of fluctuations at which two series possess cross-correlations. Applying the new coefficient to analyze the time-dependent cross-correlations of PM2.5 series between Beijing and the three neighboring cities of Tianjin, Zhangjiakou, and Baoding, we find that time lags between the PM2.5 series with larger fluctuations are longer than those between PM2.5 series withsmaller fluctuations. Our analysis also shows that cross-correlations between the PM2.5 series of two neighboring cities are significant and the time lags between two PM2.5 series of neighboring cities are significantly non-zero. These findings providenew scientific support on the view that air pollution in neighboring cities can affect one another not simultaneously but with a time lag.

SEARCHES FOR TIME-DEPENDENT NEUTRINO SOURCES WITH ICECUBE DATA FROM 2008 TO 2012

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

Aartsen, M. G.; Ackermann, M.; Adams, J.

2015-07-01

In this paper searches for flaring astrophysical neutrino sources and sources with periodic emission with the IceCube neutrino telescope are presented. In contrast to time-integrated searches, where steady emission is assumed, the analyses presented here look for a time-dependent signal of neutrinos using the information from the neutrino arrival times to enhance the discovery potential. A search was performed for correlations between neutrino arrival times and directions, as well as neutrino emission following time-dependent light curves, sporadic emission, or periodicities of candidate sources. These include active galactic nuclei, soft γ-ray repeaters, supernova remnants hosting pulsars, microquasars, and X-ray binaries. Themore » work presented here updates and extends previously published results to a longer period that covers 4 years of data from 2008 April 5 to 2012 May 16, including the first year of operation of the completed 86 string detector. The analyses did not find any significant time-dependent point sources of neutrinos, and the results were used to set upper limits on the neutrino flux from source candidates.« less

Estimation of time-dependent Hurst exponents with variational smoothing and application to forecasting foreign exchange rates

NASA Astrophysics Data System (ADS)

Garcin, Matthieu

2017-10-01

Hurst exponents depict the long memory of a time series. For human-dependent phenomena, as in finance, this feature may vary in the time. It justifies modelling dynamics by multifractional Brownian motions, which are consistent with time-dependent Hurst exponents. We improve the existing literature on estimating time-dependent Hurst exponents by proposing a smooth estimate obtained by variational calculus. This method is very general and not restricted to the sole Hurst framework. It is globally more accurate and easier than other existing non-parametric estimation techniques. Besides, in the field of Hurst exponents, it makes it possible to make forecasts based on the estimated multifractional Brownian motion. The application to high-frequency foreign exchange markets (GBP, CHF, SEK, USD, CAD, AUD, JPY, CNY and SGD, all against EUR) shows significantly good forecasts. When the Hurst exponent is higher than 0.5, what depicts a long-memory feature, the accuracy is higher.

Dynamic Torque and Vertical Force Analysis during Nickel-titanium Rotary Root Canal Preparation with Different Modes of Reciprocal Rotation.

PubMed

Tokita, Daisuke; Ebihara, Arata; Nishijo, Miki; Miyara, Kana; Okiji, Takashi

2017-10-01

The purpose of the present study was to compare 2 modes of reciprocal movement (torque-sensitive and time-dependent reciprocal rotation) with continuous rotation in terms of torque and apical force generation during nickel-titanium rotary root canal instrumentation. A custom-made automated root canal instrumentation and torque/force analyzing device was used to prepare simulated canals in resin blocks and monitor the torque and apical force generated in the blocks during preparation. Experimental groups (n = 7, each) consisted of (1) torque-sensitive reciprocal rotation with torque-sensitive vertical movement (group TqR), (2) time-dependent reciprocal rotation with time-dependent vertical movement (group TmR), and (3) continuous rotation with time-dependent vertical movement (group CR). The canals were instrumented with TF Adaptive SM1 and SM2 rotary files (SybronEndo, Orange, CA), and the torque and apical force were measured during instrumentation with SM2. The mean and maximum torque and apical force values were statistically analyzed using 1-way analysis of variance and the Tukey test (α = 0.05). The recordings showed intermittent increases of upward apical force and clockwise torque, indicating the generation and release of screw-in forces. The maximum upward apical force values in group TmR were significantly smaller than those in group CR (P < .05). The maximum torque values in clockwise and counterclockwise directions in groups TqR and TmR were significantly smaller than those in group CR (P < .05). Under the present experimental conditions using TF Adaptive instruments, both torque-sensitive and time-dependent reciprocal rotation generated significantly lower maximum torque and may have advantages in reducing stress generation caused by screw-in forces when compared with continuous rotation. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Areca nut chewing and dependency syndrome: is the dependence comparable to smoking? a cross sectional study.

PubMed

Mirza, Saira S; Shafique, Kashif; Vart, Priya; Arain, Moin I

2011-08-18

Areca nut is the seed of fruit oriental palm known as Areca catechu. Many adverse effects of nut chewing have been well documented in the medical literature. As these nuts are mixed with some other substances like tobacco and flavouring agents, it has been hypothesized that it might also cause some dependency symptoms among its users. Therefore, the objective of this study was to investigate dependency syndrome among areca nut users with and without tobacco additives and compare it with dependency associated with cigarette smoking among the male Pakistani population. This was an observational cross sectional study carried out on healthy individuals, who were users of any one of the three products (areca nut only, areca nut with tobacco additives, cigarette smokers). Participants were selected by convenience sampling of people coming to hospital to seek a free oral check up. Information was collected about the socio-demographic profile, pattern of use and symptoms of dependency using the DSM-IV criteria for substance dependence. We carried out multiple logistic regressions to investigate association between socio-demographic profile, pattern of substance use and dependency syndrome. We carried out final analysis on 851 individuals, of which 36.8% (n = 314) were areca nut users, 28.4% (n = 242) were the chewers of areca with tobacco additives and 34.7% (n = 295) were regular cigarette smokers. Multivariate analyses showed that individuals using areca nut with tobacco additives were significantly more likely to have dependency syndrome (OR = 2.17, 95% CI 1.39-3.40) while cigarette smokers were eight times more likely to have dependency syndrome as compared to areca nut only users. Areca nut use with and without tobacco additives was significantly associated with dependency syndrome. In comparison to exclusive areca nut users, the smokers were eight times more likely to develop dependence while areca nut users with tobacco additives were also significantly more likely to suffer from the dependence.

Internet Teleprescence by Real-Time View-Dependent Image Generation with Omnidirectional Video Camera

NASA Astrophysics Data System (ADS)

Morita, Shinji; Yamazawa, Kazumasa; Yokoya, Naokazu

2003-01-01

This paper describes a new networked telepresence system which realizes virtual tours into a visualized dynamic real world without significant time delay. Our system is realized by the following three steps: (1) video-rate omnidirectional image acquisition, (2) transportation of an omnidirectional video stream via internet, and (3) real-time view-dependent perspective image generation from the omnidirectional video stream. Our system is applicable to real-time telepresence in the situation where the real world to be seen is far from an observation site, because the time delay from the change of user"s viewing direction to the change of displayed image is small and does not depend on the actual distance between both sites. Moreover, multiple users can look around from a single viewpoint in a visualized dynamic real world in different directions at the same time. In experiments, we have proved that the proposed system is useful for internet telepresence.

Computing Finite-Time Lyapunov Exponents with Optimally Time Dependent Reduction

NASA Astrophysics Data System (ADS)

Babaee, Hessam; Farazmand, Mohammad; Sapsis, Themis; Haller, George

2016-11-01

We present a method to compute Finite-Time Lyapunov Exponents (FTLE) of a dynamical system using Optimally Time-Dependent (OTD) reduction recently introduced by H. Babaee and T. P. Sapsis. The OTD modes are a set of finite-dimensional, time-dependent, orthonormal basis {ui (x , t) } |i=1N that capture the directions associated with transient instabilities. The evolution equation of the OTD modes is derived from a minimization principle that optimally approximates the most unstable directions over finite times. To compute the FTLE, we evolve a single OTD mode along with the nonlinear dynamics. We approximate the FTLE from the reduced system obtained from projecting the instantaneous linearized dynamics onto the OTD mode. This results in a significant reduction in the computational cost compared to conventional methods for computing FTLE. We demonstrate the efficiency of our method for double Gyre and ABC flows. ARO project 66710-EG-YIP.

The critical role of p16/Rb pathway in the inhibition of GH3 cell cycle induced by T-2 toxin.

PubMed

Fatima, Zainab; Guo, Pu; Huang, Deyu; Lu, Qirong; Wu, Qinghua; Dai, Menghong; Cheng, Guyue; Peng, Dapeng; Tao, Yanfei; Ayub, Muhammad; Ul Qamar, Muhammad Tahir; Ali, Muhammad Waqar; Wang, Xu; Yuan, Zonghui

2018-05-01

T-2 toxin is a worldwide trichothecenetoxin and can cause various toxicities.T-2 toxin is involved in G1 phase arrest in several cell lines but molecular mechanism is still not clear. In present study, we used rat pituitary GH3 cells to investigate the mechanism involved in cell cycle arrest against T-2 toxin (40 nM) for 12, 24, 36 and 48 h as compared to control cells. GH3 cells showed a considerable increase in reactive oxygen species (ROS) as well as loss in mitochondrial membrane potential (△Ym) upon exposure to the T-2 toxin. Flow cytometry showed a significant time-dependent increase in percentage of apoptotic cells and gel electrophoresis showed the hallmark of apoptosis oligonucleosomal DNA fragmentation. Additionally, T-2 toxin-induced oxidative stress and DNA damage with a time-dependent significant increased expression of p53 favors the apoptotic process by the activation of caspase-3 in T-2 toxin treated cells. Cell cycle analysis by flow cytometry revealed a time-dependent increase ofG1 cell population along with the significant time-dependent up-regulation of mRNA and protein expression of p16 and p21 and significant down-regulation of cyclin D1, CDK4, and p-RB levels further verify the G1 phase arrest in GH3 cells. Morphology of GH3 cells by TEM clearly showed the damage and dysfunction to mitochondria and the cell nucleus. These findings for the first time demonstrate that T-2 toxin induces G1 phase cell cycle arrest by the involvement of p16/Rb pathway, along with ROS mediated oxidative stress and DNA damage with p53 and caspase cascade interaction, resulting in apoptosis in GH3 cells. Copyright © 2018 Elsevier B.V. All rights reserved.

Generalization bounds of ERM-based learning processes for continuous-time Markov chains.

PubMed

Zhang, Chao; Tao, Dacheng

2012-12-01

Many existing results on statistical learning theory are based on the assumption that samples are independently and identically distributed (i.i.d.). However, the assumption of i.i.d. samples is not suitable for practical application to problems in which samples are time dependent. In this paper, we are mainly concerned with the empirical risk minimization (ERM) based learning process for time-dependent samples drawn from a continuous-time Markov chain. This learning process covers many kinds of practical applications, e.g., the prediction for a time series and the estimation of channel state information. Thus, it is significant to study its theoretical properties including the generalization bound, the asymptotic convergence, and the rate of convergence. It is noteworthy that, since samples are time dependent in this learning process, the concerns of this paper cannot (at least straightforwardly) be addressed by existing methods developed under the sample i.i.d. assumption. We first develop a deviation inequality for a sequence of time-dependent samples drawn from a continuous-time Markov chain and present a symmetrization inequality for such a sequence. By using the resultant deviation inequality and symmetrization inequality, we then obtain the generalization bounds of the ERM-based learning process for time-dependent samples drawn from a continuous-time Markov chain. Finally, based on the resultant generalization bounds, we analyze the asymptotic convergence and the rate of convergence of the learning process.

Baclofen for the Treatment of Alcohol Dependence and Possible Role of Comorbid Anxiety

PubMed Central

Morley, K.C.; Baillie, A.; Leung, S.; Addolorato, G.; Leggio, L.; Haber, P.S.

2014-01-01

Aim: To conduct a double-blind, placebo-controlled randomized clinical trial of baclofen in the treatment of alcohol dependence. Methods: Out of 69 participants consecutively screened, 42 alcohol-dependent patients were randomized to receive placebo, baclofen 30 mg/day or baclofen 60 mg/day for 12 weeks. All subjects were offered BRENDA, a structured psychosocial therapy for alcohol dependence that seeks to improve motivation for change, enhance strategies to prevent relapse and encourage compliance with treatment. Results: Intention-to-treat analyses revealed that alcohol consumption (heavy drinking days, drinks per drinking day) significantly reduced across all three groups during the treatment period. There were no statistically significant advantages to treatment on time to first heavy drinking day (relapse) (P = 0.08), nor time to first drink (lapse) (P = 0.18). A post hoc analysis stratifying according to whether there had been a comorbid anxiety disorder, revealed a beneficial effect of baclofen 30 mg/day versus placebo on time to lapse and relapse (P < 0.05). There was also a beneficial effect for baclofen 60 mg/day relative to placebo on time to relapse in this comorbid group (P < 0.05). Both doses of baclofen were well tolerated. There were no serious adverse events. Conclusions: In spite of the small sample for a 3-arm clinical trial, this study suggests a specific role of baclofen in alcohol-dependent individuals with comorbid anxiety. Replication in larger, fully-powered studies is required. PMID:25246489

Elastic light scattering from single cells: orientational dynamics in optical trap.

PubMed

Watson, Dakota; Hagen, Norbert; Diver, Jonathan; Marchand, Philippe; Chachisvilis, Mirianas

2004-08-01

Light-scattering diagrams (phase functions) from single living cells and beads suspended in an optical trap were recorded with 30-ms time resolution. The intensity of the scattered light was recorded over an angular range of 0.5-179.5 degrees using an optical setup based on an elliptical mirror and rotating aperture. Experiments revealed that light-scattering diagrams from biological cells exhibit significant and complex time dependence. We have attributed this dependence to the cell's orientational dynamics within the trap. We have also used experimentally measured phase function information to calculate the time dependence of the optical radiation pressure force on the trapped particle and show how it changes depending on the orientation of the particle. Relevance of these experiments to potential improvement in the sensitivity of label-free flow cytometry is discussed.

Spin-dependent delay time and Hartman effect in asymmetrical graphene barrier under strain

NASA Astrophysics Data System (ADS)

Sattari, Farhad; Mirershadi, Soghra

2018-01-01

We study the spin-dependent tunneling time, including group delay and dwell time, in a graphene based asymmetrical barrier with Rashba spin-orbit interaction in the presence of strain, sandwiched between two normal leads. We find that the spin-dependent tunneling time can be efficiently tuned by the barrier width, and the bias voltage. Moreover, for the zigzag direction strain although the oscillation period of the dwell time does not change, the oscillation amplitude increases by increasing the incident electron angle. It is found that for the armchair direction strain unlike the zigzag direction the group delay time at the normal incidence depends on the spin state of electrons and Hartman effect can be observed. In addition, for the armchair direction strain the spin polarization increases with increasing the RSOI strength and the bias voltage. The magnitude and sign of spin polarization can be manipulated by strain. In particular, by applying an external electric field the efficiency of the spin polarization is improved significantly in strained graphene, and a fully spin-polarized current is generated.

Electrokinetically driven microfluidic mixing with patchwise surface heterogeneity and AC applied electric field

NASA Astrophysics Data System (ADS)

Luo, Win-Jet; Yue, Cheng-Feng

2004-12-01

This paper investigates two-dimensional, time-dependent electroosmotic flows driven by an AC electric field via patchwise surface heterogeneities distributed along the microchannel walls. The time-dependent flow fields through the microchannel are simulated for various patchwise heterogeneous surface patterns using the backwards-Euler time stepping numerical method. Different heterogeneous surface patterns are found to create significantly different electrokinetic transport phenomena. It is shown that the presence of oppositely charged surface heterogeneities on the microchannel walls results in the formation of localized flow circulations within the bulk flow. These circulation regions grow and decay periodically in accordance with the applied periodic AC electric field intensity. The circulations provide an effective means of enhancing species mixing in the microchannel. A suitable design of the patchwise heterogeneous surface pattern permits the mixing channel length and the retention time required to attain a homogeneous solution to be reduced significantly.

Explicit symplectic algorithms based on generating functions for relativistic charged particle dynamics in time-dependent electromagnetic field

NASA Astrophysics Data System (ADS)

Zhang, Ruili; Wang, Yulei; He, Yang; Xiao, Jianyuan; Liu, Jian; Qin, Hong; Tang, Yifa

2018-02-01

Relativistic dynamics of a charged particle in time-dependent electromagnetic fields has theoretical significance and a wide range of applications. The numerical simulation of relativistic dynamics is often multi-scale and requires accurate long-term numerical simulations. Therefore, explicit symplectic algorithms are much more preferable than non-symplectic methods and implicit symplectic algorithms. In this paper, we employ the proper time and express the Hamiltonian as the sum of exactly solvable terms and product-separable terms in space-time coordinates. Then, we give the explicit symplectic algorithms based on the generating functions of orders 2 and 3 for relativistic dynamics of a charged particle. The methodology is not new, which has been applied to non-relativistic dynamics of charged particles, but the algorithm for relativistic dynamics has much significance in practical simulations, such as the secular simulation of runaway electrons in tokamaks.

Progress Report on Alloy 617 Time Dependent Allowables

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

Wright, Julie Knibloe

2015-06-01

Time dependent allowable stresses are required in the ASME Boiler and Pressure Vessel Code for design of components in the temperature range where time dependent deformation (i.e., creep) is expected to become significant. There are time dependent allowable stresses in Section IID of the Code for use in the non-nuclear construction codes, however, there are additional criteria that must be considered in developing time dependent allowables for nuclear components. These criteria are specified in Section III NH. St is defined as the lesser of three quantities: 100% of the average stress required to obtain a total (elastic, plastic, primary andmore » secondary creep) strain of 1%; 67% of the minimum stress to cause rupture; and 80% of the minimum stress to cause the initiation of tertiary creep. The values are reported for a range of temperatures and for time increments up to 100,000 hours. These values are determined from uniaxial creep tests, which involve the elevated temperature application of a constant load which is relatively small, resulting in deformation over a long time period prior to rupture. The stress which is the minimum resulting from these criteria is the time dependent allowable stress St. In this report data from a large number of creep and creep-rupture tests on Alloy 617 are analyzed using the ASME Section III NH criteria. Data which are used in the analysis are from the ongoing DOE sponsored high temperature materials program, form Korea Atomic Energy Institute through the Generation IV VHTR Materials Program and historical data from previous HTR research and vendor data generated in developing the alloy. It is found that the tertiary creep criterion determines St at highest temperatures, while the stress to cause 1% total strain controls at low temperatures. The ASME Section III Working Group on Allowable Stress Criteria has recommended that the uncertainties associated with determining the onset of tertiary creep and the lack of significant cavitation associated with early tertiary creep strain suggest that the tertiary creep criteria is not appropriate for this material. If the tertiary creep criterion is dropped from consideration, the stress to rupture criteria determines St at all but the lowest temperatures.« less

The relationship between crystalline methamphetamine use and methamphetamine dependence.

PubMed

McKetin, Rebecca; Kelly, Erin; McLaren, Jennifer

2006-12-01

The aim of the current study was to determine whether crystalline methamphetamine users are more dependent on methamphetamine than people who use other forms of the drug, and if so, whether this could be accounted for by their methamphetamine use history. A structured face-to-face interview was used to assess drug use patterns and demographics among a convenience sample of 309 regular methamphetamine users from Sydney, Australia. Dependence on methamphetamine in the past year was measured using the Severity of Dependence Scale. The use of crystalline methamphetamine in the past year was confirmed using a photographic identification sheet. Participants who had used crystalline methamphetamine in the past year were significantly more likely to be dependent on methamphetamine than participants who took only other forms of methamphetamine during this time (61% versus 39%). Methamphetamine dependence was also associated with injecting or smoking methamphetamine (67% and 58%, respectively versus 30% for intranasal or oral use), using methamphetamine more than weekly (68% versus 34%), having used the drug for more than 5 years (61% versus 36%), and having used 'base' methamphetamine in the past year (59% versus 39%). Crystalline methamphetamine use remained significantly associated with methamphetamine dependence after adjusting for these patterns of methamphetamine use. Methamphetamine users who took crystalline methamphetamine in the past year were more likely to be dependent than methamphetamine users who had not taken the crystalline form of the drug during this time.

Prevalence of exercise dependence and other behavioral addictions among clients of a Parisian fitness room.

PubMed

Lejoyeux, Michel; Avril, Marine; Richoux, Charlotte; Embouazza, Houcine; Nivoli, Fabrizia

2008-01-01

Exercise dependence is an inadequate pattern of exercise leading to clinically significant negative consequences. Subjects present loss of control of their physical activity, tolerance, and withdrawal symptoms when they do not practice sport. We studied the prevalence of exercise dependence among clients of a Parisian fitness room. We also assessed alcohol and nicotine use disorders, 2 other "socially tolerated" behavioral addictions (compulsive buying and Internet addiction), and 2 disorders related to anxiety focused on the body (bulimia and hypochondria). All clients of the fitness room 18 years and older were invited to participate in the study. Three hundred subjects were included; 125 (42%) presented diagnostic criteria of exercise dependence. Unsurprisingly, exercise dependents spent more hours each day in the fitness center practicing (2.1 vs 1.5 hours per day). They went to the fitness center more often each week (3.5 vs 2.9 days per week). Exercise addicts smoked less; alcohol consumption was equivalent in both groups. Compulsive buying was significantly more frequent in exercise dependents (63% vs 38%), which means they scored higher in the compulsive buying scale (5.4 vs 4.1). Prevalence of hypochondria was equivalent in both groups, but scores in the Whiteley Index of Hypochondria were higher (4.1 vs 3) in the exercise-dependent group. Bulimia was significantly more frequent among exercise dependents (70% vs 47%), who also presented a higher number of bulimic episodes each week (2.5 vs 1.3). Subjects with exercise dependence spent more time on their computer each day (3.9 vs 2.4 hours per day). We found no difference regarding time spent using Internet, the number of e-mails sent or received, and their time at speaking on a cellular phone. Our results lead to systematically study the addictive relation to exercise among regular clients of the fitness rooms. Exercise addicts are exposed to negative consequences for their excess of physical activity. Exercise addiction is also associated to compulsive buying, bulimia, and, in a lesser extent, hypochondria.

A Randomized, Double-Blind, Placebo-Controlled Trial of Citicoline for Cocaine Dependence in Bipolar I Disorder.

PubMed

Brown, E Sherwood; Todd, Jackie Peterson; Hu, Lisa T; Schmitz, Joy M; Carmody, Thomas J; Nakamura, Alyson; Sunderajan, Prabha; Rush, A John; Adinoff, Bryon; Bret, Mary Ellen; Holmes, Traci; Lo, Alexander

2015-10-01

Although drug dependence is common in patients with bipolar disorder, minimal data are available on the treatment of drug dependence in this patient population. The authors previously reported a decreased risk of relapse to cocaine use in a pilot study of citicoline in patients with bipolar disorder and cocaine dependence. The primary aim of the present study was to determine whether citicoline reduces cocaine use in outpatients with bipolar I disorder and current cocaine dependence and active cocaine use. A total of 130 outpatients with bipolar I disorder (depressed or mixed mood state) and cocaine dependence received citicoline or placebo add-on therapy for 12 weeks. Results of thrice-weekly urine drug screens were analyzed using a generalized linear mixed model that was fitted to the binary outcome of cocaine-positive screens at each measurement occasion for 12 weeks. Mood was assessed with the Inventory of Depressive Symptomatology-Self Report, the Hamilton Depression Rating Scale, and the Young Mania Rating Scale. In the intent-to-treat sample (N=61 in both groups), significant treatment group and group-by-time effects were observed, whether or not missing urine screens were imputed as cocaine positive. The group effect was greatest early in the study and tended to decline with time. No between-group differences in mood symptoms or side effects were observed. Citicoline was well tolerated for treatment of cocaine dependence in patients with bipolar disorder. Cocaine use was significantly reduced with citicoline initially, although treatment effects diminished over time, suggesting the need for augmentation strategies to optimize long-term benefit.

Central nervous system drug consumption depending on the time between symptom onset and the diagnosis of Alzheimer's disease: an analysis by the Registry of Dementias of Girona.

PubMed

Calvó-Perxas, Laia; López-Pousa, Secundino; Vilalta-Franch, Joan; Turró-Garriga, Oriol; Blankenburg, Michael; Febrer, Laia; Flaqué, Margarida; Vallmajó, Natàlia; Aguirregomozcorta, Maria; Genís, David; Casas, Isabel; Perkal, Héctor; Coromina, Joan; Garre-Olmo, Josep

2012-01-01

To describe central nervous system (CNS) drug consumption patterns depending on the time to diagnosis of Alzheimer's disease (AD), and to check whether the cases diagnosed later are associated with greater severity and consuming more CNS drugs. Cross-sectional study using 952 cases of the Registry of Dementias of Girona. A binary logistic regression was used to detect variables associated with the use of CNS drugs depending on the time to diagnosis. CNS drugs were consumed by 95.8% of the AD patients. Only antipsychotics presented a statistically significant increase in the frequency of prescription to patients with longer time elapsed from symptom onset to AD diagnosis. Longer time elapsed from the onset of symptoms to the diagnosis resulted in increased probability of antipsychotic consumption. Copyright © 2012 S. Karger AG, Basel.

GC-MS based metabolite profiling of rice Koji fermentation by various fungi.

PubMed

Kim, Ah Jin; Choi, Jung Nam; Kim, Jiyoung; Park, Sait Byul; Yeo, Soo Hwan; Choi, Ji Ho; Lee, Choong Hwan

2010-01-01

In this study, Aspergillus kawachii, Aspergillus oryzae, and Rhizopus sp., were utilized for rice Koji fermentation, and the metabolites were analyzed in a time-dependent manner by gas chromatography-mass spectrometry. On Principal Component Analysis, the metabolite patterns were clearly distinguished based on the fungi species. This approach revealed that the quantities of glucose, galactose, and glycerol gradually increased as a function of fermentation time in all trials rice Koji fermentation. The time-dependent changes of these metabolites showed significant increases in glucose in the A. oryzae-treated rice, and in glycerol and galactose in the A. kawachii-treated rice. In addition, glycolysis-related enzyme activities were correlated with the changes in these metabolites. The results indicate that time-dependent metabolite production has the potential to be a valuable tool in selecting inoculant fungi and the optimal fermentation time for rice koji.

Predictive factors in patients with hepatocellular carcinoma receiving sorafenib therapy using time-dependent receiver operating characteristic analysis.

PubMed

Nishikawa, Hiroki; Nishijima, Norihiro; Enomoto, Hirayuki; Sakamoto, Azusa; Nasu, Akihiro; Komekado, Hideyuki; Nishimura, Takashi; Kita, Ryuichi; Kimura, Toru; Iijima, Hiroko; Nishiguchi, Shuhei; Osaki, Yukio

2017-01-01

To investigate variables before sorafenib therapy on the clinical outcomes in hepatocellular carcinoma (HCC) patients receiving sorafenib and to further assess and compare the predictive performance of continuous parameters using time-dependent receiver operating characteristics (ROC) analysis. A total of 225 HCC patients were analyzed. We retrospectively examined factors related to overall survival (OS) and progression free survival (PFS) using univariate and multivariate analyses. Subsequently, we performed time-dependent ROC analysis of continuous parameters which were significant in the multivariate analysis in terms of OS and PFS. Total sum of area under the ROC in all time points (defined as TAAT score) in each case was calculated. Our cohort included 175 male and 50 female patients (median age, 72 years) and included 158 Child-Pugh A and 67 Child-Pugh B patients. The median OS time was 0.68 years, while the median PFS time was 0.24 years. On multivariate analysis, gender, body mass index (BMI), Child-Pugh classification, extrahepatic metastases, tumor burden, aspartate aminotransferase (AST) and alpha-fetoprotein (AFP) were identified as significant predictors of OS and ECOG-performance status, Child-Pugh classification and extrahepatic metastases were identified as significant predictors of PFS. Among three continuous variables (i.e., BMI, AST and AFP), AFP had the highest TAAT score for the entire cohort. In subgroup analyses, AFP had the highest TAAT score except for Child-Pugh B and female among three continuous variables. In continuous variables, AFP could have higher predictive accuracy for survival in HCC patients undergoing sorafenib therapy.

Anhedonia: Its Dynamic Relations With Craving, Negative Affect, and Treatment During a Quit Smoking Attempt.

PubMed

Cook, Jessica W; Lanza, Stephanie T; Chu, Wanghuan; Baker, Timothy B; Piper, Megan E

2017-06-01

Research shows that abstinence from tobacco leads to a withdrawal-related decrement in responsivity to nondrug rewards (ie, anhedonia). However, it remains unclear how anhedonia relates to other key withdrawal symptoms and withdrawal-related constructs over time. We analyzed ecological momentary assessment data to examine whether a decrement in response to rewards during a 10-day period following quitting shows a pattern of associations with other variables (ie, treatment, tobacco dependence, negative affect, and craving) that is consistent with anhedonia being a tobacco withdrawal symptom. As part of a randomized controlled trial of smoking cessation therapies, 1122 adults (58% female) were assigned to: placebo (n = 131), bupropion (alone or with nicotine lozenge; n = 401), or nicotine replacement therapy (NRT; lozenge, patch, both; n = 590). Participants completed 4 ecological momentary assessments per day for 10 days postquit, resulting in 22 575 assessments. Time-varying effect modeling showed that anhedonia was significantly greater among those high in dependence relative to lower dependent smokers out to day 9 postquit. The placebo group showed elevated anhedonia immediately postquit, which fell to levels similar to the treatment groups by day 7. NRT effectively reduced anhedonia and its time-varying association with craving early in the quit attempt. The positive association between negative affect and anhedonia was moderate and stable over time for both active treatment groups. These results provide additional support that anhedonia following quitting smoking is a manifestation of the tobacco withdrawal syndrome. This study supported the hypothesis that diminished responsivity to nondrug rewards (ie, anhedonia) is a symptom of the tobacco withdrawal syndrome. Results showed that anhedonia: (1) was significantly associated with dependence, especially during the early postquit period when withdrawal was at its peak intensity; (2) showed significant time-varying associations with other withdrawal symptoms, especially craving; and (3) was significantly suppressed by agonist administration as was its association with craving over time. © The Author 2017. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Experimental Identification and Simulation of Time and/or Rate Dependent Reversible and Irreversible Deformation Regions for both a Titanium and Nickel Alloy

NASA Technical Reports Server (NTRS)

Arnold, Steven M.; Lerch, Bradley A.; Sellers, Cory

2013-01-01

In this paper time and/or rate dependent deformation regions are experimentally mapped out as a function of temperature. It is clearly demonstrated that the concept of a threshold stress (a stress that delineate reversible and irreversible behavior) is valid and necessary at elevated temperatures and corresponds to the classical yield stress at lower temperatures. Also the infinitely slow modulus, (Es) i.e. the elastic modulus of the material if it was loaded at an infinitely slow strain rate, and the "dynamic modulus", modulus, Ed, which represents the modulus of the material if it is loaded at an infinitely fast rate are used to delineate rate dependent from rate independent regions. As demonstrated at elevated temperatures there is a significant difference between the two modulus values, thus indicating both significant time-dependence and rate dependence. In the case of the nickel-based super alloy, ME3, this behavior is also shown to be grain size specific. Consequently, at higher temperatures viscoelastic behavior exist below k (i.e., the threshold stress) and at stresses above k the behavior is viscoplastic. Finally a multi-mechanism, stress partitioned viscoelastic model, capable of being consistently coupled to a viscoplastic model is characterized over the full temperature range investigated for Ti-6-4 and ME3.

Extended Lagrangian Excited State Molecular Dynamics

DOE PAGES

Bjorgaard, Josiah August; Sheppard, Daniel Glen; Tretiak, Sergei; ...

2018-01-09

In this work, an extended Lagrangian framework for excited state molecular dynamics (XL-ESMD) using time-dependent self-consistent field theory is proposed. The formulation is a generalization of the extended Lagrangian formulations for ground state Born–Oppenheimer molecular dynamics [Phys. Rev. Lett. 2008 100, 123004]. The theory is implemented, demonstrated, and evaluated using a time-dependent semiempirical model, though it should be generally applicable to ab initio theory. The simulations show enhanced energy stability and a significantly reduced computational cost associated with the iterative solutions of both the ground state and the electronically excited states. Relaxed convergence criteria can therefore be used both formore » the self-consistent ground state optimization and for the iterative subspace diagonalization of the random phase approximation matrix used to calculate the excited state transitions. In conclusion, the XL-ESMD approach is expected to enable numerically efficient excited state molecular dynamics for such methods as time-dependent Hartree–Fock (TD-HF), Configuration Interactions Singles (CIS), and time-dependent density functional theory (TD-DFT).« less

Extended Lagrangian Excited State Molecular Dynamics

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

Bjorgaard, Josiah August; Sheppard, Daniel Glen; Tretiak, Sergei

In this work, an extended Lagrangian framework for excited state molecular dynamics (XL-ESMD) using time-dependent self-consistent field theory is proposed. The formulation is a generalization of the extended Lagrangian formulations for ground state Born–Oppenheimer molecular dynamics [Phys. Rev. Lett. 2008 100, 123004]. The theory is implemented, demonstrated, and evaluated using a time-dependent semiempirical model, though it should be generally applicable to ab initio theory. The simulations show enhanced energy stability and a significantly reduced computational cost associated with the iterative solutions of both the ground state and the electronically excited states. Relaxed convergence criteria can therefore be used both formore » the self-consistent ground state optimization and for the iterative subspace diagonalization of the random phase approximation matrix used to calculate the excited state transitions. In conclusion, the XL-ESMD approach is expected to enable numerically efficient excited state molecular dynamics for such methods as time-dependent Hartree–Fock (TD-HF), Configuration Interactions Singles (CIS), and time-dependent density functional theory (TD-DFT).« less

Extended Lagrangian Excited State Molecular Dynamics.

PubMed

Bjorgaard, J A; Sheppard, D; Tretiak, S; Niklasson, A M N

2018-02-13

An extended Lagrangian framework for excited state molecular dynamics (XL-ESMD) using time-dependent self-consistent field theory is proposed. The formulation is a generalization of the extended Lagrangian formulations for ground state Born-Oppenheimer molecular dynamics [Phys. Rev. Lett. 2008 100, 123004]. The theory is implemented, demonstrated, and evaluated using a time-dependent semiempirical model, though it should be generally applicable to ab initio theory. The simulations show enhanced energy stability and a significantly reduced computational cost associated with the iterative solutions of both the ground state and the electronically excited states. Relaxed convergence criteria can therefore be used both for the self-consistent ground state optimization and for the iterative subspace diagonalization of the random phase approximation matrix used to calculate the excited state transitions. The XL-ESMD approach is expected to enable numerically efficient excited state molecular dynamics for such methods as time-dependent Hartree-Fock (TD-HF), Configuration Interactions Singles (CIS), and time-dependent density functional theory (TD-DFT).

Differential anti-tumor activity of coriolus versicolor (Yunzhi) extract through p53- and/or Bcl-2-dependent apoptotic pathway in human breast cancer cells.

PubMed

Ho, Cheong-Yip; Kim, Chi-Fai; Leung, Kwok-Nam; Fung, Kwok-Pui; Tse, Tak-Fu; Chan, Helen; Lau, Clara Bik-San

2005-06-01

Coriolus versicolor (CV), also called Yunzhi, has been demonstrated to exert anti-tumor effects on various types of cancer cells, but the underlying mechanism has not been fully elucidated. The present study aimed to evaluate the in vitro anti-tumor activity of a standardized aqueous ethanol extract prepared from CV on four breast cancer cell lines using MTT assay, and test whether the mechanism involves apoptosis induction and modulation of p53 and Bcl-2 protein expressions using cell death detection ELISA, p53 and Bcl-2 ELISAs respectively. Our results demonstrated that the CV extract dose-dependently suppressed the proliferation of three breast tumor cell lines, with ascending order of IC50 values: T-47D, MCF-7, MDA-MB-231, while BT-20 cells were not significantly affected. Tumoricidal activity of the CV extract was found to be comparable to a chemotherapeutic anti-cancer drug, mitomycin C. Nucleosome productions in apoptotic MDA-MB-231, MCF-7 and T-47D cells were significantly augmented in a time-dependent manner and paralleled the anti-proliferative activity of CV extract. Expression of p53 protein was significantly upregulated only in T-47D cells treated with the CV extract in a dose- and time-dependent fashion, but not in MCF-7 (except at 400 mug/ml after 16 h) and MDA-MB-231 cells. The CV extract significantly induced a dose-dependent downregulation of Bcl-2 protein expression in MCF-7 and T-47D cells, but not in MDA-MB-231 cells. These results suggested that apoptosis induction, differentially dependent of p53 and Bcl-2 expressions, might be the possible mechanism of CV extract-mediated cytotoxicity in human breast cancer cells in vitro.

Detecting Moving Targets by Use of Soliton Resonances

NASA Technical Reports Server (NTRS)

Zak, Michael; Kulikov, Igor

2003-01-01

A proposed method of detecting moving targets in scenes that include cluttered or noisy backgrounds is based on a soliton-resonance mathematical model. The model is derived from asymptotic solutions of the cubic Schroedinger equation for a one-dimensional system excited by a position-and-time-dependent externally applied potential. The cubic Schroedinger equation has general significance for time-dependent dispersive waves. It has been used to approximate several phenomena in classical as well as quantum physics, including modulated beams in nonlinear optics, and superfluids (in particular, Bose-Einstein condensates). In the proposed method, one would take advantage of resonant interactions between (1) a soliton excited by the position-and-time-dependent potential associated with a moving target and (2) eigen-solitons, which represent dispersive waves and are solutions of the cubic Schroedinger equation for a time-independent potential.

Time-Dependent Reversible-Irreversible Deformation Threshold Determined Explicitly by Experimental Technique

NASA Technical Reports Server (NTRS)

Castelli, Michael G.; Arnold, Steven M.

2000-01-01

Structural materials for the design of advanced aeropropulsion components are usually subject to loading under elevated temperatures, where a material's viscosity (resistance to flow) is greatly reduced in comparison to its viscosity under low-temperature conditions. As a result, the propensity for the material to exhibit time-dependent deformation is significantly enhanced, even when loading is limited to a quasi-linear stress-strain regime as an effort to avoid permanent (irreversible) nonlinear deformation. An understanding and assessment of such time-dependent effects in the context of combined reversible and irreversible deformation is critical to the development of constitutive models that can accurately predict the general hereditary behavior of material deformation. To this end, researchers at the NASA Glenn Research Center at Lewis Field developed a unique experimental technique that identifies the existence of and explicitly determines a threshold stress k, below which the time-dependent material deformation is wholly reversible, and above which irreversible deformation is incurred. This technique is unique in the sense that it allows, for the first time, an objective, explicit, experimental measurement of k. The underlying concept for the experiment is based on the assumption that the material s time-dependent reversible response is invariable, even in the presence of irreversible deformation.

Direction Dependent Effects In Widefield Wideband Full Stokes Radio Imaging

NASA Astrophysics Data System (ADS)

Jagannathan, Preshanth; Bhatnagar, Sanjay; Rau, Urvashi; Taylor, Russ

2015-01-01

Synthesis imaging in radio astronomy is affected by instrumental and atmospheric effects which introduce direction dependent gains.The antenna power pattern varies both as a function of time and frequency. The broad band time varying nature of the antenna power pattern when not corrected leads to gross errors in full stokes imaging and flux estimation. In this poster we explore the errors that arise in image deconvolution while not accounting for the time and frequency dependence of the antenna power pattern. Simulations were conducted with the wideband full stokes power pattern of the Very Large Array(VLA) antennas to demonstrate the level of errors arising from direction-dependent gains. Our estimate is that these errors will be significant in wide-band full-pol mosaic imaging as well and algorithms to correct these errors will be crucial for many up-coming large area surveys (e.g. VLASS)

Race/Ethnic Disparities in the Utilization of Treatment for Drug Dependent Inmates in U.S. State Correctional Facilities

PubMed Central

Nowotny, Kathryn M.

2014-01-01

This study examines race/ethnic disparities in treatment for drug dependent inmates in state correctional facilities. The data come from the 2004 Survey of Inmates in State Correctional Facilities. Fixed effects logistic regression is used to analyze treatment outcomes for 5,180 inmates housed within 286 prisons. The analysis accounts for differences in background characteristics (i.e., age, gender, marital status, foreign born status, veteran status), socioeconomic characteristics (i.e., education, employment prior to incarceration), mental health (i.e., diagnosis with a serious mental illness), and incarceration experiences (i.e., current conviction, previous incarceration episodes, time served, additional sentencing requirements, external social support, disciplinary violations). The findings identify a remarkable unmet need among drug dependent inmates in that less than one-half of drug dependent inmates had received any type of treatment in prison at the time of the interview with the most common treatment type being self-help groups. Compared to whites, drug dependent Latino inmates have significantly lower odds of utilizing treatment, yet there are no significant black-white disparities found. Implications for drug treatment within prisons are discussed. PMID:25270722

Modeling hurricane evacuation traffic : development of a time-dependent hurricane evacuation demand model.

DOT National Transportation Integrated Search

2006-04-01

Little attention has been given to estimating dynamic travel demand in transportation planning in the past. However, when factors influencing travel are changing significantly over time such as with an approaching hurricane - dynamic demand and t...

A cross-syndrome study of the differential effects of sleep on declarative memory consolidation in children with neurodevelopmental disorders.

PubMed

Ashworth, Anna; Hill, Catherine M; Karmiloff-Smith, Annette; Dimitriou, Dagmara

2017-03-01

Sleep plays an active role in memory consolidation. Because children with Down syndrome (DS) and Williams syndrome (WS) experience significant problems with sleep and also with learning, we predicted that sleep-dependent memory consolidation would be impaired in these children when compared to typically developing (TD) children. This is the first study to provide a cross-syndrome comparison of sleep-dependent learning in school-aged children. Children with DS (n = 20) and WS (n = 22) and TD children (n = 33) were trained on the novel Animal Names task where they were taught pseudo-words as the personal names of ten farm and domestic animals, e.g. Basco the cat, with the aid of animal picture flashcards. They were retested following counterbalanced retention intervals of wake and sleep. Overall, TD children remembered significantly more words than both the DS and WS groups. In addition, their performance improved following night-time sleep, whereas performance over the wake retention interval remained stable, indicating an active role of sleep for memory consolidation. Task performance of children with DS did not significantly change following wake or sleep periods. However, children with DS who were initially trained in the morning continued to improve on the task at the following retests, so that performance on the final test was greater for children who had initially trained in the morning than those who trained in the evening. Children with WS improved on the task between training and the first retest, regardless of whether sleep or wake occurred during the retention interval. This suggests time-dependent rather than sleep-dependent learning in children with WS, or tiredness at the end of the first session and better performance once refreshed at the start of the second session, irrespective of the time of day. Contrary to expectations, sleep-dependent learning was not related to baseline level of performance. The findings have significant implications for educational strategies, and suggest that children with DS should be taught more important or difficult information in the morning when they are better able to learn, whilst children with WS should be allowed a time delay between learning phases to allow for time-dependent memory consolidation, and frequent breaks from learning so that they are refreshed and able to perform at their best. © 2015 The Authors. Developmental Science Published by John Wiley & Sons Ltd.

Communication: Rigorous quantum dynamics of O + O{sub 2} exchange reactions on an ab initio potential energy surface substantiate the negative temperature dependence of rate coefficients

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

Li, Yaqin; Sun, Zhigang, E-mail: zsun@dicp.ac.cn, E-mail: dawesr@mst.edu, E-mail: hguo@unm.edu; Center for Advanced Chemical Physics, University of Science and Technology of China, 96 Jinzhai Road, Hefei 230026

2014-08-28

The kinetics and dynamics of several O + O{sub 2} isotope exchange reactions have been investigated on a recently determined accurate global O{sub 3} potential energy surface using a time-dependent wave packet method. The agreement between calculated and measured rate coefficients is significantly improved over previous work. More importantly, the experimentally observed negative temperature dependence of the rate coefficients is for the first time rigorously reproduced theoretically. This negative temperature dependence can be attributed to the absence in the new potential energy surface of a submerged “reef” structure, which was present in all previous potential energy surfaces. In addition, contributionsmore » of rotational excited states of the diatomic reactant further accentuate the negative temperature dependence.« less

Shoulder pain and time dependent structure in wheelchair propulsion variability

PubMed Central

Jayaraman, Chandrasekaran; Moon, Yaejin; Sosnoff, Jacob J.

2016-01-01

Manual wheelchair propulsion places considerable repetitive mechanical strain on the upper limbs leading to shoulder injury and pain. While recent research indicates that the amount of variability in wheelchair propulsion and shoulder pain may be related. There has been minimal inquiry into the fluctuation over time (i.e. time-dependent structure) in wheelchair propulsion variability. Consequently the purpose of this investigation was to examine if the time-dependent structure in the wheelchair propulsion parameters are related to shoulder pain. 27 experienced wheelchair users manually propelled their own wheelchair fitted with a SMARTWheel on a roller at 1.1 m/s for 3 minutes. Time-dependent structure of cycle-to-cycle fluctuations in contact angle and inter push time interval was quantified using sample entropy (SampEn) and compared between the groups with/without shoulder pain using non-parametric statistics. Overall findings were, (1) variability observed in contact angle fluctuations during manual wheelchair propulsion is structured (Z=3.15;p<0.05), (2) individuals with shoulder pain exhibited higher SampEn magnitude for contact angle during wheelchair propulsion than those without pain (χ2(1)=6.12;p<0.05); and (3) SampEn of contact angle correlated significantly with self-reported shoulder pain (rs (WUSPI) =0.41;rs (VAS)=0.56;p<0.05). It was concluded that the time-dependent structure in wheelchair propulsion may provide novel information for tracking and monitoring shoulder pain. PMID:27134151

Triggering up states in all-to-all coupled neurons

NASA Astrophysics Data System (ADS)

Ngo, H.-V. V.; Köhler, J.; Mayer, J.; Claussen, J. C.; Schuster, H. G.

2010-03-01

Slow-wave sleep in mammalians is characterized by a change of large-scale cortical activity currently paraphrased as cortical Up/Down states. A recent experiment demonstrated a bistable collective behaviour in ferret slices, with the remarkable property that the Up states can be switched on and off with pulses, or excitations, of same polarity; whereby the effect of the second pulse significantly depends on the time interval between the pulses. Here we present a simple time-discrete model of a neural network that exhibits this type of behaviour, as well as quantitatively reproduces the time dependence found in the experiments.

Control of dephasing in rotationally hot molecules

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

Bartram, David; Ivanov, Misha

We consider a rotationally hot diatomic molecule as an example of an open quantum system, where molecular vibrational wave packets are subject to dephasing due to rovibrational coupling. We report analytical and numerical results addressing whether the dephasing rate can be controlled by adjustment of the initial wave packet phases. It appears that over long time scales, phase-only control is not possible, but for earlier time scales the possibility of phase-only control of dephasing remains. In addition, we point out that the time dependence of the dephasing process depends significantly upon the degeneracy of the rotational environment states.

Mouse strain differences in immobility and sensitivity to fluvoxamine and desipramine in the forced swimming test: analysis of serotonin and noradrenaline transporter binding.

PubMed

Sugimoto, Yumi; Kajiwara, Yoshinobu; Hirano, Kazufumi; Yamada, Shizuo; Tagawa, Noriko; Kobayashi, Yoshiharu; Hotta, Yoshihiro; Yamada, Jun

2008-09-11

Strain differences in immobility time in the forced swimming test were investigated in five strains of mice, namely, ICR, ddY, C57BL/6, DBA/2 and BALB/c mice. There were significant strain differences. The immobility times of ICR, ddY and C57BL/6 mice were longer than those of DBA/2 and BALB/c mice. Immobility times were not significantly related to locomotor activity in these strains. There were also differences in sensitivity to the selective serotonin reuptake inhibitor (SSRI) fluvoxamine. In ICR, ddY and C57BL/6 mice, fluvoxamine did not affect immobility time, while it reduced the immobility time of DBA/2 and BALB/c mice dose-dependently. The noradrenaline reuptake inhibitor desipramine decreased immobility time in all strains of mice. Serotonin (5-HT) transporter binding in the brains of all five strains of mice was also investigated. Analysis of 5-HT transporter binding revealed significant strain differences, being lower in DBA/2 and BALB/c mice than in other strains of mice. The amount of 5-HT transporter binding was correlated to baseline immobility time. However, there was no significant relation between noradrenaline transporter binding and immobility time. These results suggest that the duration of baseline immobility depends on the levels of 5-HT transporter binding, leading to apparent strain differences in immobility time in the forced swimming test. Furthermore, differences in 5-HT transporter binding may cause variations in responses to fluvoxamine.

[Effect of rhynchophylline on behaviors of methamphetamine-dependent zebrafish and the mechanism].

PubMed

Chen, Yi-Fei; Peng, Ju; Fang, Miao; Liu, Yi; Nie, Ling-Hui; Mo, Zhi-Xian; Zhu, Ling-Ling

2016-11-20

To observe the effect of rhynchophylline on methamphetamine-dependent zebrafish and explore the possible mechanism. Zebrafish were divided into control group, amphetamine group, low- (50 mg/kg) and high (100 mg/kg)-dose rhynchophylline groups, and ketamine (150 mg/kg) group. Conditioned place preference (CPP) was induced in zebrafish with methamphetamine, and the staying time in the drug box and the tracking map of the zebrafish were observed with Noldus Ethovision XT system. The protein expressions of TH, NR2B and GLUR2 in the brain of zebrafish with CPP were detected with Western blotting. Compared with the control group, zebrafish in methamphetamine group showed significant variations in the staying time and swimming distance in the drug box after conditioning (P<0.05) with obvious alterations of NR2B, TH and GLUR2 expressions in the brain (P<0.05). Treatment of methamphetamine-dependent zebrafish with high-dose rhynchophylline significantly reduced the variations in the staying time and swimming distance in the drug box (P<0.05) and in the expressions of NR2B, TH and GLUR2 in the brain (P<0.05). Rhynchophylline can inhibit methamphetamine dependence in zebrafish, the mechanism of which may involve the expressions of TH, NR2B and GLUR2 proteins in the brain.

Days with pain and substance use disorders: is there an association?

PubMed

Edlund, Mark J; Sullivan, Mark D; Han, Xiaotong; Booth, Brenda M

2013-08-01

We investigated possible associations between pain frequency and the 5 most common substance use disorders: alcohol abuse/dependence, cocaine abuse/dependence, methamphetamine abuse/dependence, opioid abuse/dependence, and marijuana abuse/dependence. We used data from the Rural Stimulant Study, a longitudinal (7 waves), observational study of at-risk stimulant users (cocaine and methamphetamine) in Arkansas and Kentucky (n=462). In fixed-effects logistic regression models, we regressed our measures of substance use disorders on the number of days with pain in the past 30 days and depression severity. Time periods when individuals had 1 to 15 days [odds ratio (OR)=1.85, P<0.001] or 16+ days (OR=2.18, P<0.001) with pain in the past 30 days were more likely to have a diagnosis of alcohol abuse/dependence, compared with time periods when individuals had no days with pain. Compared with time periods when individuals had no pain days in the past 30 days, time periods when individuals had 16+ pain days were more likely to have a diagnosis of opioid abuse/dependence (OR=3.32, P=0.02). Number of days with pain was not significantly associated with other substance use disorders. Pain frequency seems to be associated with an increased risk for alcohol abuse/dependence and opioid abuse/dependence in this population, and the magnitude of the association is medium to large. Further research is needed to investigate this in more representative populations and to determine causal relationships.

The Influence of the Brain on Overpopulation, Ageing and Dependency.

ERIC Educational Resources Information Center

Cape, Ronald D. T.

1989-01-01

With time, an increasing number in the world population is becoming old, and changes in the aging brain mean that a significant proportion of the aged are likely to be dependent on others. The devotion of resources to research into the aging brain could bring benefits far outweighing the investment. (Author/CW)

Total ozone trend significance from space time variability of daily Dobson data

NASA Technical Reports Server (NTRS)

Wilcox, R. W.

1981-01-01

Estimates of standard errors of total ozone time and area means, as derived from ozone's natural temporal and spatial variability and autocorrelation in middle latitudes determined from daily Dobson data are presented. Assessing the significance of apparent total ozone trends is equivalent to assessing the standard error of the means. Standard errors of time averages depend on the temporal variability and correlation of the averaged parameter. Trend detectability is discussed, both for the present network and for satellite measurements.

The delayed rectifier potassium conductance in the sarcolemma and the transverse tubular system membranes of mammalian skeletal muscle fibers

PubMed Central

DiFranco, Marino; Quinonez, Marbella

2012-01-01

A two-microelectrode voltage clamp and optical measurements of membrane potential changes at the transverse tubular system (TTS) were used to characterize delayed rectifier K currents (IKV) in murine muscle fibers stained with the potentiometric dye di-8-ANEPPS. In intact fibers, IKV displays the canonical hallmarks of KV channels: voltage-dependent delayed activation and decay in time. The voltage dependence of the peak conductance (gKV) was only accounted for by double Boltzmann fits, suggesting at least two channel contributions to IKV. Osmotically treated fibers showed significant disconnection of the TTS and displayed smaller IKV, but with similar voltage dependence and time decays to intact fibers. This suggests that inactivation may be responsible for most of the decay in IKV records. A two-channel model that faithfully simulates IKV records in osmotically treated fibers comprises a low threshold and steeply voltage-dependent channel (channel A), which contributes ∼31% of gKV, and a more abundant high threshold channel (channel B), with shallower voltage dependence. Significant expression of the IKV1.4 and IKV3.4 channels was demonstrated by immunoblotting. Rectangular depolarizing pulses elicited step-like di-8-ANEPPS transients in intact fibers rendered electrically passive. In contrast, activation of IKV resulted in time- and voltage-dependent attenuations in optical transients that coincided in time with the peaks of IKV records. Normalized peak attenuations showed the same voltage dependence as peak IKV plots. A radial cable model including channels A and B and K diffusion in the TTS was used to simulate IKV and average TTS voltage changes. Model predictions and experimental data were compared to determine what fraction of gKV in the TTS accounted simultaneously for the electrical and optical data. Best predictions suggest that KV channels are approximately equally distributed in the sarcolemma and TTS membranes; under these conditions, >70% of IKV arises from the TTS. PMID:22851675

Alprazolam use and dependence. A retrospective analysis of 30 cases of withdrawal.

PubMed Central

Dickinson, B; Rush, P A; Radcliffe, A B

1990-01-01

From 1986 to 1989, the Chemical Dependency Recovery Program at Kaiser Permanente Hospital, Fontana, California, admitted an increasing number of patients for alprazolam dependence. Severe withdrawal reactions and adverse consequences with use were reported in the literature. In this review of 30 cases of alprazolam dependence and subsequent withdrawal, there was a statistically significant increase in the number of patient hospital days, the subjective symptoms, and staff time spent with patients compared with those in alcoholic controls. Most patients with diagnosed alprazolam dependence used doses in the range recommended by the package information at the time of admission. Patients with low preadmission doses of 1 mg or less per day showed notable withdrawal symptoms. The average duration of use was 29.9 months, considerably longer than suggested effective ranges. Most patients (28) had a chemical dependence history before being placed on alprazolam therapy; 24 had a positive family history of chemical dependence; and 24 had previous or current psychiatric care. PMID:2349800

Multiscale time-dependent density functional theory: Demonstration for plasmons.

PubMed

Jiang, Jiajian; Abi Mansour, Andrew; Ortoleva, Peter J

2017-08-07

Plasmon properties are of significant interest in pure and applied nanoscience. While time-dependent density functional theory (TDDFT) can be used to study plasmons, it becomes impractical for elucidating the effect of size, geometric arrangement, and dimensionality in complex nanosystems. In this study, a new multiscale formalism that addresses this challenge is proposed. This formalism is based on Trotter factorization and the explicit introduction of a coarse-grained (CG) structure function constructed as the Weierstrass transform of the electron wavefunction. This CG structure function is shown to vary on a time scale much longer than that of the latter. A multiscale propagator that coevolves both the CG structure function and the electron wavefunction is shown to bring substantial efficiency over classical propagators used in TDDFT. This efficiency follows from the enhanced numerical stability of the multiscale method and the consequence of larger time steps that can be used in a discrete time evolution. The multiscale algorithm is demonstrated for plasmons in a group of interacting sodium nanoparticles (15-240 atoms), and it achieves improved efficiency over TDDFT without significant loss of accuracy or space-time resolution.

Stress generation in a developmental context: the role of youth depressive symptoms, maternal depression, the parent-child relationship, and family stress.

PubMed

Chan, Priscilla T; Doan, Stacey N; Tompson, Martha C

2014-02-01

The present study examined stress generation in a developmental and family context among 171 mothers and their preadolescent children, ages 8-12 years, at baseline (Time 1) and 1-year follow-up (Time 2). In the current study, we examined the bidirectional relationship between children's depressive symptoms and dependent family stress. Results suggest that children's baseline level of depressive symptoms predicted the generation of dependent family stress 1 year later. However, baseline dependent family stress did not predict an increase in children's depressive symptoms 1 year later. In addition, we examined whether a larger context of both child chronic strain (indicated by academic, behavioral, and peer stress) and family factors, including socioeconomic status and parent-child relationship quality, would influence the stress generation process. Although both chronic strain and socioeconomic status were not associated with dependent family stress at Time 2, poorer parent-child relationship quality significantly predicted greater dependent family stress at Time 2. Child chronic strain, but neither socioeconomic status nor parent-child relationship quality, predicted children's depression symptoms at Time 2. Finally, gender, maternal depression history, and current maternal depressive symptoms did not moderate the relationship between level of dependent family stress and depressive symptoms. Overall, findings provide partial support for a developmental stress generation model operating in the preadolescent period.

Experimental verification of a real-time tuning method of a model-based controller by perturbations to its poles

NASA Astrophysics Data System (ADS)

Kajiwara, Itsuro; Furuya, Keiichiro; Ishizuka, Shinichi

2018-07-01

Model-based controllers with adaptive design variables are often used to control an object with time-dependent characteristics. However, the controller's performance is influenced by many factors such as modeling accuracy and fluctuations in the object's characteristics. One method to overcome these negative factors is to tune model-based controllers. Herein we propose an online tuning method to maintain control performance for an object that exhibits time-dependent variations. The proposed method employs the poles of the controller as design variables because the poles significantly impact performance. Specifically, we use the simultaneous perturbation stochastic approximation (SPSA) to optimize a model-based controller with multiple design variables. Moreover, a vibration control experiment of an object with time-dependent characteristics as the temperature is varied demonstrates that the proposed method allows adaptive control and stably maintains the closed-loop characteristics.

Hydrocortisone-induced anti-inflammatory effects in immature human enterocytes depend on the timing of exposure.

PubMed

Rautava, Samuli; Walker, W Allan; Lu, Lei

2016-06-01

The immature human gut has a propensity to exaggerated inflammatory responses that are thought to play a role in the pathogenesis of necrotizing enterocolitis (NEC). Prenatal exposure to corticosteroids has been reported to reduce the risk of NEC, while postnatal dexamethasone treatment is associated with adverse neurodevelopmental outcomes in preterm infants. The aim of this study was to investigate the direct role of hydrocortisone in gene expression patterns and inflammatory responses in immature human enterocytes. Time-dependent hydrocortisone effects in nontransformed primary human fetal intestinal epithelial cell line H4 were investigated by cDNA microarray. Fetal intestinal organ culture and cell culture experiments were conducted. Inflammatory responses were induced by stimulation with IL-1β and TNF-α with and without hydrocortisone. IL-8 and IL-6 expression and secretion were measured as functional readout. Here we report time-dependent hydrocortisone-induced changes in gene expression patterns detected by cDNA microarray. Hydrocortisone significantly attenuated IL-1β-induced inflammatory responses in the immature human gut when administered at the time of the proinflammatory insult: IL-1β-induced IL-8 and IL-6 secretion in the fetal ileum as well as H4 cells were significantly reduced. Hydrocortisone also inhibited IL-8 secretion in response to TNF-α. In contrast, TNF-α-induced IL-8 secretion was not reduced in cells treated with hydrocortisone for 48 h before stimulation. Our observations provide a physiological basis for understanding the differential clinical effects of corticosteroids in the immature human gut depending on the timing of treatment. Copyright © 2016 the American Physiological Society.

Hydrocortisone-induced anti-inflammatory effects in immature human enterocytes depend on the timing of exposure

PubMed Central

Rautava, Samuli; Lu, Lei

2016-01-01

The immature human gut has a propensity to exaggerated inflammatory responses that are thought to play a role in the pathogenesis of necrotizing enterocolitis (NEC). Prenatal exposure to corticosteroids has been reported to reduce the risk of NEC, while postnatal dexamethasone treatment is associated with adverse neurodevelopmental outcomes in preterm infants. The aim of this study was to investigate the direct role of hydrocortisone in gene expression patterns and inflammatory responses in immature human enterocytes. Time-dependent hydrocortisone effects in nontransformed primary human fetal intestinal epithelial cell line H4 were investigated by cDNA microarray. Fetal intestinal organ culture and cell culture experiments were conducted. Inflammatory responses were induced by stimulation with IL-1β and TNF-α with and without hydrocortisone. IL-8 and IL-6 expression and secretion were measured as functional readout. Here we report time-dependent hydrocortisone-induced changes in gene expression patterns detected by cDNA microarray. Hydrocortisone significantly attenuated IL-1β-induced inflammatory responses in the immature human gut when administered at the time of the proinflammatory insult: IL-1β-induced IL-8 and IL-6 secretion in the fetal ileum as well as H4 cells were significantly reduced. Hydrocortisone also inhibited IL-8 secretion in response to TNF-α. In contrast, TNF-α-induced IL-8 secretion was not reduced in cells treated with hydrocortisone for 48 h before stimulation. Our observations provide a physiological basis for understanding the differential clinical effects of corticosteroids in the immature human gut depending on the timing of treatment. PMID:27056727

RAFT-synthesized Graft Copolymers that Enhance pH-dependent Membrane Destabilization and Protein Circulation Times

PubMed Central

Crownover, Emily; Duvall, Craig L.; Convertine, Anthony; Hoffman, Allan S.; Stayton, Patrick S.

2012-01-01

Here we describe a new graft copolymer architecture of poly(propylacrylic acid) (polyPAA) that displays potent pH-dependent, membrane-destabilizing activity and in addition is shown to enhance protein blood circulation kinetics. PolyPAA containing a single telechelic alkyne functionality was prepared via reversible addition-fragmentation chain transfer (RAFT) polymerization with an alkyne-functional chain transfer agent (CTA) and coupled to RAFT polymerized poly(azidopropyl methacrylate) (polyAPMA) through azide-alkyne [3+2] Huisgen cycloaddition. The graft copolymers become membrane destabilizing at endosomal pH values and are active at significantly lower concentrations than the linear polyPAA. A biotin terminated polyPAA graft copolymer was prepared by grafting PAA onto polyAPMA polymerized with a biotin functional RAFT CTA. The blood circulation time and biodistribution of tritium labeled avidin conjugated to the polyPAA graft copolymer was characterized along with a clinically utilized 40 kDa branched polyethylene glycol (PEG) also possessing biotin functionalization. The linear and graft polyPAA increase the area under the curve (AUC) over avidin alone by 9 and 12 times, respectively. Furthermore, polyPAA graft copolymer conjugates accumulated in tumor tissue significantly more than the linear polyPAA and the branched PEG conjugates. The collective data presented in this report indicate that the polyPAA graft copolymers exhibit robust pH-dependent, membrane-destabilizing activity, low cytotoxicity and significantly enhance blood circulation time and tumor accumulation. PMID:21699931

Time-dependent classification accuracy curve under marker-dependent sampling.

PubMed

Zhu, Zhaoyin; Wang, Xiaofei; Saha-Chaudhuri, Paramita; Kosinski, Andrzej S; George, Stephen L

2016-07-01

Evaluating the classification accuracy of a candidate biomarker signaling the onset of disease or disease status is essential for medical decision making. A good biomarker would accurately identify the patients who are likely to progress or die at a particular time in the future or who are in urgent need for active treatments. To assess the performance of a candidate biomarker, the receiver operating characteristic (ROC) curve and the area under the ROC curve (AUC) are commonly used. In many cases, the standard simple random sampling (SRS) design used for biomarker validation studies is costly and inefficient. In order to improve the efficiency and reduce the cost of biomarker validation, marker-dependent sampling (MDS) may be used. In a MDS design, the selection of patients to assess true survival time is dependent on the result of a biomarker assay. In this article, we introduce a nonparametric estimator for time-dependent AUC under a MDS design. The consistency and the asymptotic normality of the proposed estimator is established. Simulation shows the unbiasedness of the proposed estimator and a significant efficiency gain of the MDS design over the SRS design. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Inhibition of soluble epoxide hydrolase contributes to the anti-inflammatory effect of antimicrobial triclocarban in a murine model

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

Liu Junyan; Qiu Hong; Morisseau, Christophe

The increasing use of the antimicrobial triclocarban (TCC) in personal care products (PCPs) has resulted in concern regarding environmental pollution. TCC is a potent inhibitor of soluble epoxide hydrolase (sEH). Inhibitors of sEH (sEHIs) are anti-inflammatory, anti-hypertensive and cardio-protective in multiple animal models. However, the in vivo effects anticipated from a sEHI have not been reported for TCC. Here we demonstrated the anti-inflammatory effects in vivo of TCC in a murine model. TCC was employed in a lipopolysaccharide (LPS)-challenged murine model. Systolic blood pressure, plasma levels of several inflammatory cytokines and chemokine, and metabolomic profile of plasma oxylipins were determined.more » TCC significantly reversed LPS-induced morbid hypotension in a time-dependent manner. TCC significantly repressed the increased release of inflammatory cytokines and chemokine caused by LPS. Furthermore, TCC significantly shifted the oxylipin profile in vivo in a time-dependent manner towards resolution of inflammation as expected from a sEHI. These results demonstrated that at the doses used TCC is anti-inflammatory in the murine model. This study suggests that TCC may provide some benefits in humans in addition to its antimicrobial activities due to its potent inhibition of sEH. It may be a promising starting point for developing new low volume high value applications of TCC. However these biological effects also caution against the general over use of TCC in PCPs. - Graphical abstract: Display Omitted Research Highlights: > Anti-microbial triclocarban (TCC) is anti-inflammatory in a murine model. > TCC significantly shifted the oxylipin profile in vivo as expected from a sEHI. > TCC significantly reversed LPS-induced morbid hypotension in a time-dependent manner. > TCC significantly repressed LPS-induced increased release of inflammatory cytokines.« less

Tetrapentylammonium block of chloramine-T and veratridine modified rat brain type IIA sodium channels

PubMed Central

Ghatpande, A S; Rao, S; Sikdar, S K

2001-01-01

Tetrapentylammonium (TPeA) block of rat brain type IIA sodium channel α subunit was studied using whole cell patch clamp. Results indicate that TPeA blocks the inactivating brain sodium channel in a potential and use-dependent manner similar to that of the cardiac sodium channel. Removal of inactivation using chloramine-T (CT) unmasks a time-dependent block by TPeA consistent with slow blocking kinetics. On the other hand, no time dependence is observed when inactivation is abolished by modification with veratridine. TPeA does not bind in a potential-dependent fashion to veratridine-modified channels and does not significantly affect gating of veratridine-modified channels suggesting that high affinity binding of TPeA to the brain sodium channel is lost after veratridine modification. PMID:11309247

Arab Americans' acculturation and tobacco smoking.

PubMed

Al-Omari, Hasan; Scheibmeir, Monica

2009-04-01

Limited information is available about Arab Americans' smoking behaviors. The aim of this study was to describe Arab Americans' smoking behaviors and any relationship between tobacco dependence and acculturation. This was a cross-sectional study. Arab American smokers and ex-smokers (N = 96) participated in the study. Nicotine dependence, acculturation, and tobacco use questionnaires were used to measure the major variables. Analyses revealed a significant positive correlation between acculturation and tobacco dependence and between tobacco exposure and tobacco dependence. Arab Americans who behaved most like their ethnic peers and spent more time with Arab Americans were more dependent on nicotine.

Density regulation in Northeast Atlantic fish populations: Density dependence is stronger in recruitment than in somatic growth.

PubMed

Zimmermann, Fabian; Ricard, Daniel; Heino, Mikko

2018-05-01

Population regulation is a central concept in ecology, yet in many cases its presence and the underlying mechanisms are difficult to demonstrate. The current paradigm maintains that marine fish populations are predominantly regulated by density-dependent recruitment. While it is known that density-dependent somatic growth can be present too, its general importance remains unknown and most practical applications neglect it. This study aimed to close this gap by for the first time quantifying and comparing density dependence in growth and recruitment over a large set of fish populations. We fitted density-dependent models to time-series data on population size, recruitment and age-specific weight from commercially exploited fish populations in the Northeast Atlantic Ocean and the Baltic Sea. Data were standardized to enable a direct comparison within and among populations, and estimated parameters were used to quantify the impact of density regulation on population biomass. Statistically significant density dependence in recruitment was detected in a large proportion of populations (70%), whereas for density dependence in somatic growth the prevalence of density dependence depended heavily on the method (26% and 69%). Despite age-dependent variability, the density dependence in recruitment was consistently stronger among age groups and between alternative approaches that use weight-at-age or weight increments to assess growth. Estimates of density-dependent reduction in biomass underlined these results: 97% of populations with statistically significant parameters for growth and recruitment showed a larger impact of density-dependent recruitment on population biomass. The results reaffirm the importance of density-dependent recruitment in marine fishes, yet they also show that density dependence in somatic growth is not uncommon. Furthermore, the results are important from an applied perspective because density dependence in somatic growth affects productivity and catch composition, and therefore the benefits of maintaining fish populations at specific densities. © 2018 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society.

Contrasting gender differences on two measures of exercise dependence.

PubMed

Weik, M; Hale, B D

2009-03-01

Recent studies using multidimensional measures have shown that men (Exercise Dependence Scale; EDS-R) are more exercise-dependent than women, whereas others have found that women (Exercise Dependence Questionnaire; EDQ) are more exercise-dependent than men. This study investigated whether there may be sex differences in exercise dependence or whether the questionnaires may be measuring different dimensions of exercise dependence. Regular exercisers voluntarily completed the EDS-R, EDQ and Drive for Thinness (DFT) subscale before or after a workout. A local health club in the eastern USA. Male (n = 102) and female (n = 102) exercisers completed the three questionnaires, but 11 participants (1 man, 10 women) were excluded from further analysis because scores indicated possible secondary exercise dependence (eating disorder). Eight subscales of the EDQ, seven subscales of the EDS, the DFT subscale, and several demographic variables served as dependent measures. A multivariate analysis of variance (MANOVA) on the EDS-R showed that men were significantly higher than women on the Withdrawal, Continuance, Tolerance, Lack of Control, Time, and Intention Effect subscales. Another MANOVA on the EDQ indicated that women scored significantly higher than did men on the Interference, Positive Rewards, Withdrawal, and Social Reasons subscales. Statistical analysis using t tests revealed that men had significantly higher total EDS-R scores than women, but women had significantly higher EDQ and DFT scores. These results suggest that both questionnaires measure different aspects of exercise dependence that favour either gender. It remains for further research to determine whether these instruments are equally viable for measurement of ED in both men and women.

The Local Structure of Globalization. The Network Dynamics of Foreign Direct Investments in the International Electricity Industry

NASA Astrophysics Data System (ADS)

Koskinen, Johan; Lomi, Alessandro

2013-05-01

We study the evolution of the network of foreign direct investment (FDI) in the international electricity industry during the period 1994-2003. We assume that the ties in the network of investment relations between countries are created and deleted in continuous time, according to a conditional Gibbs distribution. This assumption allows us to take simultaneously into account the aggregate predictions of the well-established gravity model of international trade as well as local dependencies between network ties connecting the countries in our sample. According to the modified version of the gravity model that we specify, the probability of observing an investment tie between two countries depends on the mass of the economies involved, their physical distance, and the tendency of the network to self-organize into local configurations of network ties. While the limiting distribution of the data generating process is an exponential random graph model, we do not assume the system to be in equilibrium. We find evidence of the effects of the standard gravity model of international trade on evolution of the global FDI network. However, we also provide evidence of significant dyadic and extra-dyadic dependencies between investment ties that are typically ignored in available research. We show that local dependencies between national electricity industries are sufficient for explaining global properties of the network of foreign direct investments. We also show, however, that network dependencies vary significantly over time giving rise to a time-heterogeneous localized process of network evolution.

[Significance of heterogenity in endothelium-dependent vasodilatation occurrence in healthy individuals with or without coronary risk factors].

PubMed

Polovina, Marija; Potpara, Tatjana; Giga, Vojislav; Ostojić, Miodrag

2009-10-01

Brachial artery flow-mediated dilation (FMD) is extensively used for non-invasive assessment of endothelial function. Traditionally, FMD is calculated as a percent change of arterial diameter from the baseline value at an arbitrary time point after cuff deflation (usually 60 seconds). Considerable individual differences in brachial artery temporal response to hyperemic stimulus have been observed, potentially influenced by the presence of atherosclerotic risk factors (RF). The importance of such differences for the evaluation of endothelial function has not been well established. The aim of the study was to determine the time course of maximal brachial artery endothelium-dependent dilation in healthy adults with and without RF, to explore the correlation of RF with brachial artery temporal response and to evaluate the importance of individual differences in temporal response for the assessment of endothelial function. A total of 115 healthy volunteers were included in the study. Out of them, 58 had no RF (26 men, mean age 44 +/-14 years) and 57 had at least one RF (29 men, mean age 45 +/-14 years). High-resolution color Doppler vascular ultrasound was used for brachial artery imaging. To determine maximal arterial diameter after cuff deflation and the time-point of maximal vasodilation off-line sequential measurements were performed every 10 seconds from 0 to 240 seconds after cuff release. True maximal FMD value was calculated as a percent change of the true maximal diameter from the baseline, and compared with FMD value calculated assuming that every participant reached maximal dilation at 60 seconds post cuff deflation (FMD60). Correlation of different RF with brachial artery temporal response was assessed. A maximal brachial artery endothelium-dependent vasodilation occurred from 30-120 seconds after cuff release, and the mean time of endothelium-dependent dilation was 68 +/-20 seconds. Individuals without RF had faster endothelium-dependent dilation (mean time 62 +/-17 seconds), and a shorter time-span (30 to 100 seconds), than participants with RF (mean time 75 +/-21 seconds, time-span 40 to 120 seconds) (p < 0.001). Time when the maximal endothelium-dependent dilation occurred was independently associated with age, serum lipid fractions (total cholesterol, LDL and HDL cholesterol), smoking, physical activity and C-reactive protein. True maximal FMD value in the whole group (6.7 +/-3.0%) was significantly higher (p < 0.001) than FMD60 (5.2 +/-3.5%). The same results were demonstrated for individuals with RF (4.9 +/- 1.7% vs 3.1 +/- 2.3%, p < 0.001) and without RF (8.4 +/- 2.9% vs 7.2 +/- 3.2%, p < 0.05). The temporal response of endothelium-dependent dilation is influenced by the presence of coronary FR and individually heterogeneous. When calculated according to the commonly used approach, i.e. 60 seconds after cuff deflation, FMD is significantly lower than the true maximal FMD. The routinely used measurement time-points for FMD assessment may not be adequate for the detection of true peak vasodilation in individual persons. More precise evaluation of endothelial function can be achieved with sequential measurement of arterial diameter after hyperemic stimulus.

The Gut Microbiome Is Altered in a Letrozole-Induced Mouse Model of Polycystic Ovary Syndrome

PubMed Central

Kelley, Scott T.; Skarra, Danalea V.; Rivera, Alissa J.; Thackray, Varykina G.

2016-01-01

Women with polycystic ovary syndrome (PCOS) have reproductive and metabolic abnormalities that result in an increased risk of infertility, diabetes and cardiovascular disease. The large intestine contains a complex community of microorganisms (the gut microbiome) that is dysregulated in humans with obesity and type 2 diabetes. Using a letrozole-induced PCOS mouse model, we demonstrated significant diet-independent changes in the gut microbial community, suggesting that gut microbiome dysbiosis may also occur in PCOS women. Letrozole treatment was associated with a time-dependent shift in the gut microbiome and a substantial reduction in overall species and phylogenetic richness. Letrozole treatment also correlated with significant changes in the abundance of specific Bacteroidetes and Firmicutes previously implicated in other mouse models of metabolic disease in a time-dependent manner. Our results suggest that the hyperandrogenemia observed in PCOS may significantly alter the gut microbiome independently of diet. PMID:26731268

Integrated Logistics Support Analysis of the International Space Station Alpha, Background and Summary of Mathematical Modeling and Failure Density Distributions Pertaining to Maintenance Time Dependent Parameters

NASA Technical Reports Server (NTRS)

Sepehry-Fard, F.; Coulthard, Maurice H.

1995-01-01

The process of predicting the values of maintenance time dependent variable parameters such as mean time between failures (MTBF) over time must be one that will not in turn introduce uncontrolled deviation in the results of the ILS analysis such as life cycle costs, spares calculation, etc. A minor deviation in the values of the maintenance time dependent variable parameters such as MTBF over time will have a significant impact on the logistics resources demands, International Space Station availability and maintenance support costs. There are two types of parameters in the logistics and maintenance world: a. Fixed; b. Variable Fixed parameters, such as cost per man hour, are relatively easy to predict and forecast. These parameters normally follow a linear path and they do not change randomly. However, the variable parameters subject to the study in this report such as MTBF do not follow a linear path and they normally fall within the distribution curves which are discussed in this publication. The very challenging task then becomes the utilization of statistical techniques to accurately forecast the future non-linear time dependent variable arisings and events with a high confidence level. This, in turn, shall translate in tremendous cost savings and improved availability all around.

Statistical Analysis of Human Body Movement and Group Interactions in Response to Music

NASA Astrophysics Data System (ADS)

Desmet, Frank; Leman, Marc; Lesaffre, Micheline; de Bruyn, Leen

Quantification of time series that relate to physiological data is challenging for empirical music research. Up to now, most studies have focused on time-dependent responses of individual subjects in controlled environments. However, little is known about time-dependent responses of between-subject interactions in an ecological context. This paper provides new findings on the statistical analysis of group synchronicity in response to musical stimuli. Different statistical techniques were applied to time-dependent data obtained from an experiment on embodied listening in individual and group settings. Analysis of inter group synchronicity are described. Dynamic Time Warping (DTW) and Cross Correlation Function (CCF) were found to be valid methods to estimate group coherence of the resulting movements. It was found that synchronicity of movements between individuals (human-human interactions) increases significantly in the social context. Moreover, Analysis of Variance (ANOVA) revealed that the type of music is the predominant factor in both the individual and the social context.

Protein Synthesis-Dependent Long-Term Memory Induced by One Single Associative Training Trial in the Parasitic Wasp Lariophagus distinguendus

ERIC Educational Resources Information Center

Steidle, Johannes L. M.; Collatz, Jana; Muller, Caroline

2006-01-01

Protein synthesis-dependent long-term memory in Apis mellifera and Drosophila melanogaster is formed after multiple trainings that are spaced in time. The parasitic wasp Lariophagus distinguendus remarkably differs from these species. It significantly responds to the artificial odor furfurylheptanoate (FFH) in olfactometer experiments, when this…

Charging in the ac Conductance of a Double Barrier Resonant Tunneling Structure

NASA Technical Reports Server (NTRS)

Anantram, M. P.; Saini, Subhash (Technical Monitor)

1998-01-01

There have been many studies of the linear response ac conductance of a double barrier resonant tunneling structure (DBRTS), both at zero and finite dc biases. While these studies are important, they fail to self consistently include the effect of the time dependent charge density in the well. In this paper, we calculate the ac conductance at both zero and finite do biases by including the effect of the time dependent charge density in the well in a self consistent manner. The charge density in the well contributes to both the flow of displacement currents in the contacts and the time dependent potential in the well. We find that including these effects can make a significant difference to the ac conductance and the total ac current is not equal to the simple average of the non-selfconsistently calculated conduction currents in the two contacts. This is illustrated by comparing the results obtained with and without the effect of the time dependent charge density included correctly. Some possible experimental scenarios to observe these effects are suggested.

Seismicity in a model governed by competing frictional weakening and healing mechanisms

NASA Astrophysics Data System (ADS)

Hillers, G.; Carlson, J. M.; Archuleta, R. J.

2009-09-01

Observations from laboratory, field and numerical work spanning a wide range of space and time scales suggest a strain dependent progressive evolution of material properties that control the stability of earthquake faults. The associated weakening mechanisms are counterbalanced by a variety of restrengthening mechanisms. The efficiency of the healing processes depends on local material properties and on rheologic, temperature, and hydraulic conditions. We investigate the relative effects of these competing non-linear feedbacks on seismogenesis in the context of evolving frictional properties, using a mechanical earthquake model that is governed by slip weakening friction. Weakening and strengthening mechanisms are parametrized by the evolution of the frictional control variable-the slip weakening rate R-using empirical relationships obtained from laboratory experiments. In our model, weakening depends on the slip of an earthquake and tends to increase R, following the behaviour of real and simulated frictional interfaces. Healing causes R to decrease and depends on the time passed since the last slip. Results from models with these competing feedbacks are compared with simulations using non-evolving friction. Compared to fixed R conditions, evolving properties result in a significantly increased variability in the system dynamics. We find that for a given set of weakening parameters the resulting seismicity patterns are sensitive to details of the restrengthening process, such as the healing rate b and a lower cutoff time, tc, up to which no significant change in the friction parameter is observed. For relatively large and small cutoff times, the statistics are typical of fixed large and small R values, respectively. However, a wide range of intermediate values leads to significant fluctuations in the internal energy levels. The frequency-size statistics of earthquake occurrence show corresponding non-stationary characteristics on time scales over which negligible fluctuations are observed in the fixed-R case. The progressive evolution implies that-except for extreme weakening and healing rates-faults and fault networks possibly are not well characterized by steady states on typical catalogue time scales, thus highlighting the essential role of memory and history dependence in seismogenesis. The results suggest that an extrapolation to future seismicity occurrence based on temporally limited data may be misleading due to variability in seismicity patterns associated with competing mechanisms that affect fault stability.

Time-Dependent Decline in Multifocal Electroretinogram Requires Faster Recording Procedures in Anesthetized Pigs

PubMed Central

Sørensen, Nina Buus; Christiansen, Anders Tolstrup; Kjær, Troels Wesenberg; Klemp, Kristian; la Cour, Morten; Kiilgaard, Jens Folke

2017-01-01

Purpose The time-dependent effect of anesthetics on the retinal function is debated. We hypothesize that in anesthetized animals there is a time-dependent decline that requires optimized multifocal electroretinogram (mfERG) recording procedures. Methods Conventional and four-frame global-flash mfERG recordings were obtained approximately 15, 60, and 150 minutes after the induction of propofol anesthesia (20 pigs) and isoflurane anesthesia (nine pigs). In six of the propofol-anesthetized pigs, the mfERG recordings were split in 3-minute segments. Two to 4 weeks after initial recordings, an intraocular injection of tetrodotoxin (TTX) was given and the mfERG was rerecorded as described above. Data were analyzed using mixed models in SAS statistical software. Results Propofol significantly decreases the conventional and global-flash amplitudes over time. The only significant effect of isoflurane is a decrease in the global-flash amplitudes. At 15 minutes after TTX injection several of the mfERG amplitudes are significantly decreased. There is a linear correlation between the conventional P1 and the global-flash DR mfERG-amplitude (R2 = 0.82, slope = 0.72, P < 0.0001). There is no significant difference between the 3-minute and the prolonged mfERG recordings for conventional amplitudes and the global-flash direct response. The global flash–induced component significantly decreases with prolonged mfERG recordings. Conclusions A 3-minute mfERG recording and a single stimulation protocol is sufficient in anesthetized pigs. Recordings should be obtained immediately after the induction of anesthesia. The effect of TTX is significant 15 minutes after injection, but is contaminated by the effect of anesthesia 90 minutes after injection. Therefore, the quality of mfERG recordings can be further improved by determining the necessary time-of-delay from intraocular injection of a drug to full effect. Translational Relevance General anesthesia is a possible source of error in mfERG recordings. Therefore, it is important to investigate the translational relevance of the results to mfERG recordings in children in general anesthesia. PMID:28377845

Testing the causality of Hawkes processes with time reversal

NASA Astrophysics Data System (ADS)

Cordi, Marcus; Challet, Damien; Muni Toke, Ioane

2018-03-01

We show that univariate and symmetric multivariate Hawkes processes are only weakly causal: the true log-likelihoods of real and reversed event time vectors are almost equal, thus parameter estimation via maximum likelihood only weakly depends on the direction of the arrow of time. In ideal (synthetic) conditions, tests of goodness of parametric fit unambiguously reject backward event times, which implies that inferring kernels from time-symmetric quantities, such as the autocovariance of the event rate, only rarely produce statistically significant fits. Finally, we find that fitting financial data with many-parameter kernels may yield significant fits for both arrows of time for the same event time vector, sometimes favouring the backward time direction. This goes to show that a significant fit of Hawkes processes to real data with flexible kernels does not imply a definite arrow of time unless one tests it.

Progress Report for Grant Number W911NF-09-1-0347 (University of Illinois - Urbana)

DTIC Science & Technology

2012-11-06

critical tunneling current is proportional to mexc, we find good agreement with this explanation via the approximate square-root dependence seen in Fig...can occur near the contact, reducing interlayer conductivity significantly. As critical tunneling current is linearly dependent on the width of the...studied the possibility of finding the same type of condensation in a 3D topological insulator, and started our work on a time- dependent theory to

Exact Time-Dependent Exchange-Correlation Potential in Electron Scattering Processes

NASA Astrophysics Data System (ADS)

Suzuki, Yasumitsu; Lacombe, Lionel; Watanabe, Kazuyuki; Maitra, Neepa T.

2017-12-01

We identify peak and valley structures in the exact exchange-correlation potential of time-dependent density functional theory that are crucial for time-resolved electron scattering in a model one-dimensional system. These structures are completely missed by adiabatic approximations that, consequently, significantly underestimate the scattering probability. A recently proposed nonadiabatic approximation is shown to correctly capture the approach of the electron to the target when the initial Kohn-Sham state is chosen judiciously, and it is more accurate than standard adiabatic functionals but ultimately fails to accurately capture reflection. These results may explain the underestimation of scattering probabilities in some recent studies on molecules and surfaces.

Run-time parallelization and scheduling of loops

NASA Technical Reports Server (NTRS)

Saltz, Joel H.; Mirchandaney, Ravi; Crowley, Kay

1990-01-01

Run time methods are studied to automatically parallelize and schedule iterations of a do loop in certain cases, where compile-time information is inadequate. The methods presented involve execution time preprocessing of the loop. At compile-time, these methods set up the framework for performing a loop dependency analysis. At run time, wave fronts of concurrently executable loop iterations are identified. Using this wavefront information, loop iterations are reordered for increased parallelism. Symbolic transformation rules are used to produce: inspector procedures that perform execution time preprocessing and executors or transformed versions of source code loop structures. These transformed loop structures carry out the calculations planned in the inspector procedures. Performance results are presented from experiments conducted on the Encore Multimax. These results illustrate that run time reordering of loop indices can have a significant impact on performance. Furthermore, the overheads associated with this type of reordering are amortized when the loop is executed several times with the same dependency structure.

Shoulder pain and time dependent structure in wheelchair propulsion variability.

PubMed

Jayaraman, Chandrasekaran; Moon, Yaejin; Sosnoff, Jacob J

2016-07-01

Manual wheelchair propulsion places considerable repetitive mechanical strain on the upper limbs leading to shoulder injury and pain. While recent research indicates that the amount of variability in wheelchair propulsion and shoulder pain may be related. There has been minimal inquiry into the fluctuation over time (i.e. time-dependent structure) in wheelchair propulsion variability. Consequently the purpose of this investigation was to examine if the time-dependent structure in the wheelchair propulsion parameters are related to shoulder pain. 27 experienced wheelchair users manually propelled their own wheelchair fitted with a SMARTWheel on a roller at 1.1m/s for 3min. Time-dependent structure of cycle-to-cycle fluctuations in contact angle and inter push time interval was quantified using sample entropy (SampEn) and compared between the groups with/without shoulder pain using non-parametric statistics. Overall findings were, (1) variability observed in contact angle fluctuations during manual wheelchair propulsion is structured (Z=3.15;p<0.05), (2) individuals with shoulder pain exhibited higher SampEn magnitude for contact angle during wheelchair propulsion than those without pain (χ(2)(1)=6.12;p<0.05); and (3) SampEn of contact angle correlated significantly with self-reported shoulder pain (rs (WUSPI) =0.41;rs (VAS)=0.56;p<0.05). It was concluded that the time-dependent structure in wheelchair propulsion may provide novel information for tracking and monitoring shoulder pain. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

Satiety and eating patterns in two species of constricting snakes.

PubMed

Nielsen, Torben P; Jacobsen, Magnus W; Wang, Tobias

2011-01-10

Satiety has been studied extensively in mammals, birds and fish but very little information exists on reptiles. Here we investigate time-dependent satiation in two species of constricting snakes, ball pythons (Python regius) and yellow anacondas (Eunectes notaeus). Satiation was shown to depend on both fasting time and prey size. In the ball pythons fed with mice of a relative prey mass RPM (mass of the prey/mass of the snake×100) of 15%, we observed a satiety response that developed between 6 and 12h after feeding, but after 24h pythons regained their appetite. With an RPM of 10% the pythons kept eating throughout the experiment. The anacondas showed a non-significant tendency for satiety to develop between 6 and 12h after ingesting a prey of 20% RPM. Unlike pythons, anacondas remained satiated after 24h. Handling time (from strike until prey swallowed) increased with RPM. We also found a significant decrease in handling time between the first and the second prey and a positive correlation between handling time and the mass of the snake. 2010 Elsevier Inc. All rights reserved.

Nicotine dependence matters: examining longitudinal association between smoking and physical activity among Canadian adults.

PubMed

Azagba, Sunday; Asbridge, Mark

2013-11-01

A number of studies point to the inverse relationship between physical activity and smoking; however, none has examined the role of nicotine dependence in physical activity participation among smokers. This study examined whether levels of nicotine dependence modify the association between leisure time physical activity and smoking status. The study used longitudinal data on 6795 adults from the Canadian National Population Health Survey (2004-2010). Generalized estimating equations were used to examine the association between physical activity, smoking, and nicotine dependence. We found that nicotine dependent smokers were significantly less likely to be physically active compared to non-smokers. Specifically, using the Fagerstrom Test for Nicotine Dependence, nicotine dependent smokers (OR 0.65, 95% CI 0.55-0.76) were less likely to be physically active while no significant difference was found for non-dependent smokers (OR 0.90, 95% CI 0.80-1.02) compared to non-smokers. Nicotine dependence matters in shaping engagement in physical activity among daily smokers. Efforts directed at promoting smoking cessation through nicotine dependence treatment intervention may provide additional benefits to health and well-being through an increased participation in physical activity. © 2013.

Detection on emamectin benzoate-induced apoptosis and DNA damage in Spodoptera frugiperda Sf-9 cell line.

PubMed

Wu, Xiwei; Zhang, Lei; Yang, Chao; Zong, Mimi; Huang, Qingchun; Tao, Liming

2016-01-01

Emamectin benzoate (EMB), an important macrocyclic lactone insecticide that belongs to the avermectin family and possesses excellent potency in controlling pests, is non-carcinogenic and non-mutagenic conducted in rats and mice, but EMB-induced cytotoxicity and genotoxicity in arthropod insect have been seldom reported yet. In the present paper, we quantified the cytotoxicity of EMB through the detections on cell viability, DNA damage, and cell apoptosis in Spodoptera frugiperda Sf-9 cells in vitro. The results showed that EMB caused a concentration- and time-dependent reduction on the viability of Sf-9 cells, and the median inhibitory concentrations (IC50) were 3.34μM at 72h of exposure. The dual acridine orange/ethidium bromide staining showed that exposure to EMB induced a significant time- and concentration-dependent increase on cell apoptosis. The alkaline comet assay revealed that EMB induced significant increases on single-strand DNA breaks, and the percentage of γH2AX-positive cells represented a time- and concentration-dependent formation of DNA double-strand breaks in Sf-9 cells. Interestingly, the similar cytotoxic actions of EMB also went for the human cancerous HeLa cells as a control cell group. Data demonstrated the potential cytotoxic effect of EMB on Sf-9 cells that was significantly greater than the effect of hydrogen peroxide at the same concentrations. Copyright © 2015 Elsevier Inc. All rights reserved.

Direct comparison of two different mesalamine formulations for the maintenance of remission in patients with ulcerative colitis: a double-blind, randomized study.

PubMed

Ito, Hiroaki; Iida, Mitsuo; Matsumoto, Takayuki; Suzuki, Yasuo; Aida, Yoshiyuki; Yoshida, Toyomitsu; Takano, Yuichi; Hibi, Toshifumi

2010-09-01

Mesalamine has been used as the first-line medication for the treatment of ulcerative colitis (UC). We directly compared the efficacy and safety of two different mesalamine formulations in the maintenance of remission in patients with UC. In a multicenter, double-blind, randomized study, 131 patients with quiescent UC were assigned to two groups: 65 to receive a pH-dependent release formulation of mesalamine at 2.4 g/day (pH-2.4 g) and 66 to receive a time-dependent release formulation of mesalamine at 2.25 g/day (Time-2.25 g). Both formulations were administered three times daily for 48 weeks. The primary endpoint was the proportion of patients without bloody stools. In the full analysis set (n = 130), the proportion of patients without bloody stools was 76.9% in the pH-2.4 g and 69.2% in the Time-2.25 g, demonstrating the noninferiority of pH-2.4 g to Time-2.25 g. No statistically significant difference in time to bloody stools was found between the two formulations (P = 0.27, log-rank test), but the time to bloody stools tended to be longer in pH-2.4 g compared to Time-2.25 g, and a similar trend was observed with regard to the time to relapse. No differences were observed between the safety profiles of the two formulations. The pH- and time-dependent release of mesalamine formulations were similarly safe and effective. Interestingly, the remission phase tended to be longer in the group that received the pH-dependent formulation compared to the group that received the time-dependent formulation (UMIN Clinical Trials Registry, no. C000000289).

Agglomeration, sedimentation, and cellular toxicity of alumina nanoparticles in cell culture medium

NASA Astrophysics Data System (ADS)

Yoon, Dokyung; Woo, Daekwang; Kim, Jung Heon; Kim, Moon Ki; Kim, Taesung; Hwang, Eung-Soo; Baik, Seunghyun

2011-06-01

The cytotoxicity of alumina nanoparticles (NPs) was investigated for a wide range of concentration (25-200 μg/mL) and incubation time (0-72 h) using floating cells (THP-1) and adherent cells (J774A.1, A549, and 293). Alumina NPs were gradually agglomerated over time although a significant portion of sedimentation occurred at the early stage within 6 h. A decrease of the viability was found in floating (THP-1) and adherent (J774A.1 and A549) cells in a dose-dependent manner. However, the time-dependent decrease in cell viability was observed only in adherent cells (J774A.1 and A549), which is predominantly related with the sedimentation of alumina NPs in cell culture medium. The uptake of alumina NPs in macrophages and an increased cell-to-cell adhesion in adherent cells were observed. There was no significant change in the viability of 293 cells. This in vitro test suggests that the agglomeration and sedimentation of alumina NPs affected cellular viability depending on cell types such as monocytes (THP-1), macrophages (J774A.1), lung carcinoma cells (A549), and embryonic kidney cells (293).

Can methadone maintenance for heroin-dependent patients retained in general practice reduce criminal conviction rates and time spent in prison?

PubMed Central

Keen, J; Rowse, G; Mathers, N; Campbell, M; Seivewright, N

2000-01-01

A retrospective analysis was made of the criminal records of 57 patients successfully retained in methadone maintenance at two general practices in Sheffield. Their criminal conviction rates and time spent in prison per year were compared for the periods before and after the start of their methadone programme. Overall, patients retained on methadone programmes in the general practices studied had significantly fewer convictions and cautions, and spent significantly less time in prison than they had before the start of treatment. PMID:10695069

A Longitudinal Study of Childhood ADHD and Substance Dependence Disorders in Early Adulthood

PubMed Central

Breyer, Jessie L.; Lee, Susanne; Winters, Ken; August, Gerald; Realmuto, George

2014-01-01

Attention-deficit/hyperactivity disorder (ADHD) is a childhood disorder that is associated with many behavioral and social problems. These problems may continue when an individual continues to meet criteria for ADHD as an adult. In this study, we describe the outcome patterns for three different groups: individuals who had ADHD as children, but no longer meet criteria as adults (Childhood-Limited ADHD, n = 71); individuals who met ADHD criteria as children and continue to meet criteria as young adults (Persistent ADHD n = 79); and a control group of individuals who did not meet ADHD diagnostic criteria in childhood or adulthood (n = 69). Groups were compared to examine differences in change in rates of alcohol, marijuana, and nicotine dependence over three time points in young adulthood (mean ages 18, 20 and 22 years). The method used is notable as this longitudinal study followed participants from childhood into young adulthood instead of relying on retrospective self-reports from adult participants. Results indicated that there were no significant group differences in change in rates of substance dependence over time. However, individuals whose ADHD persisted into adulthood were significantly more likely to meet DSM-IV criteria for alcohol, marijuana, and nicotine dependence across the three time points after controlling for age, sex, childhood stimulant medication use, and childhood conduct problems. Implications of these findings, as well as recommendations for future research, are discussed. PMID:24731117

Intake and time dependence of blueberry flavonoid-induced improvements in vascular function: a randomized, controlled, double-blind, crossover intervention study with mechanistic insights into biological activity.

PubMed

Rodriguez-Mateos, Ana; Rendeiro, Catarina; Bergillos-Meca, Triana; Tabatabaee, Setareh; George, Trevor W; Heiss, Christian; Spencer, Jeremy Pe

2013-11-01

There are very limited data regarding the effects of blueberry flavonoid intake on vascular function in healthy humans. We investigated the impact of blueberry flavonoid intake on endothelial function in healthy men and assessed potential mechanisms of action by the assessment of circulating metabolites and neutrophil NADPH oxidase activity. Two randomized, controlled, double-blind, crossover human-intervention trials were conducted with 21 healthy men. Initially, the impact of blueberry flavonoid intake on flow-mediated dilation (FMD) and polyphenol absorption and metabolism was assessed at baseline and 1, 2, 4, and 6 h after consumption of blueberry containing 766, 1278, and 1791 mg total blueberry polyphenols or a macronutrient- and micronutrient-matched control drink (0 mg total blueberry polyphenols). Second, an intake-dependence study was conducted (from baseline to 1 h) with 319, 637, 766, 1278, and 1791 mg total blueberry polyphenols and a control. We observed a biphasic time-dependent increase in FMD, with significant increases at 1-2 and 6 h after consumption of blueberry polyphenols. No significant intake-dependence was observed between 766 and 1791 mg. However, at 1 h after consumption, FMD increased dose dependently to ≤766 mg total blueberry polyphenol intake, after which FMD plateaued. Increases in FMD were closely linked to increases in circulating metabolites and by decreases in neutrophil NADPH oxidase activity at 1-2 and 6 h. Blueberry intake acutely improves vascular function in healthy men in a time- and intake-dependent manner. These benefits may be mechanistically linked to the actions of circulating phenolic metabolites on neutrophil NADPH oxidase activity. This trial was registered at clinicaltrials.gov as NCT01292954 and NCT01829542.

Dielectric analysis of depth dependent curing behavior of dental resin composites.

PubMed

Steinhaus, Johannes; Moeginger, Bernhard; Grossgarten, Mandy; Rosentritt, Martin; Hausnerova, Berenika

2014-06-01

The aim of this study is to investigate depth dependent changes of polymerization process and kinetics of visible light-curing (VLC) dental composites in real-time. The measured quantity - "ion viscosity" determined by dielectric analysis (DEA) - provides the depth dependent reaction rate which is correlated to the light intensity available in the corresponding depths derived from light transmission measurements. The ion viscosity curves of two composites (VOCO Arabesk Top and Grandio) were determined during irradiation of 40s with a light-curing unit (LCU) in specimen depths of 0.5/0.75/1.0/1.25/1.5/1.75 and 2.0mm using a dielectric cure analyzer (NETZSCH DEA 231 with Mini IDEX sensors). The thickness dependent light transmission was measured by irradiation composite specimens of various thicknesses on top of a radiometer setup. The shape of the ion viscosity curves depends strongly on the specimen thickness above the sensor. All curves exhibit a range of linear time dependency of the ion viscosity after a certain initiation time. The determined initiation times, the slopes of the linear part of the curves, and the ion viscosities at the end of the irradiation differ significantly with depth within the specimen. The slopes of the ion viscosity curves as well as the light intensity values decrease with depth and fit to the Lambert-Beer law. The corresponding attenuation coefficients are determined for Arabesk Top OA2 to 1.39mm(-1) and 1.48mm(-1), respectively, and for Grandio OA2 with 1.17 and 1.39mm(-1), respectively. For thicknesses exceeding 1.5mm a change in polymerization behavior is observed as the ion viscosity increases subsequent to the linear range indicating some kind of reaction acceleration. The two VLC composites and different specimen thicknesses discriminate significantly in their ion viscosity evolution allowing for a precise characterization of the curing process even with respect to the polymerization mechanism. Copyright © 2014. Published by Elsevier Ltd.

The development of the time dependence of the nuclear EMP electric field

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

Eng, C

The nuclear electromagnetic pulse (EMP) electric field calculated with the legacy code CHAP is compared with the field given by an integral solution of Maxwell's equations, also known as the Jefimenko equation, to aid our current understanding on the factors that affect the time dependence of the EMP. For a fair comparison the CHAP current density is used as a source in the Jefimenko equation. At first, the comparison is simplified by neglecting the conduction current and replacing the standard atmosphere with a constant density air slab. The simplicity of the resultant current density aids in determining the factors thatmore » affect the rise, peak and tail of the EMP electric field versus time. The three dimensional nature of the radiating source, i.e. sources off the line-of-sight, and the time dependence of the derivative of the current density with respect to time are found to play significant roles in shaping the EMP electric field time dependence. These results are found to hold even when the conduction current and the standard atmosphere are properly accounted for. Comparison of the CHAP electric field with the Jefimenko electric field offers a direct validation of the high-frequency/outgoing wave approximation.« less

Race/ethnic disparities in the utilization of treatment for drug dependent inmates in U.S. state correctional facilities.

PubMed

Nowotny, Kathryn M

2015-01-01

Research has documented racial and ethnic disparities in utilization, access, continuity, and quality of care for psychiatric disorders including treatment for substance use disorders among those with similar need in the general community. Currently, the extent of racial and ethnic disparities in treatment within U.S. correctional facilities is unknown. This study examines race/ethnic disparities in treatment for drug dependent inmates using the 2004 Survey of Inmates in State Correctional Facilities. Fixed effects logistic regression is used to analyze treatment outcomes for 5180 inmates housed within 286 prisons. The analysis accounts for differences in background characteristics (i.e., age, gender, marital status, foreign born status, veteran status), socioeconomic characteristics (i.e., education, employment prior to incarceration), mental health (i.e., diagnosis with a serious mental illness), and incarceration experiences (i.e., current conviction, previous incarceration episodes, time served, additional sentencing requirements, external social support, disciplinary violations). The findings identify a remarkable unmet need among drug dependent inmates in that less than one-half of drug dependent inmates had received any type of treatment in prison at the time of the interview with the most common treatment type being self-help groups. Compared to whites, drug dependent Latino inmates have significantly lower odds of utilizing treatment, yet there are no significant black--white disparities found. The current study suggests that treatment for drug dependent inmates needs to be expanded to include clinically or medically based treatment since the failure to address addictions in the criminal legal system has been identified as the single most significant reason for rearrest and recidivism once released. Copyright © 2014 Elsevier Ltd. All rights reserved.

Motivation to change and posttreatment temptation to drink: a multicenter study among alcohol-dependent patients.

PubMed

Fiabane, Elena; Ottonello, Marcella; Zavan, Valeria; Pistarini, Caterina; Giorgi, Ines

2017-01-01

An inpatient 28-day rehabilitation program for alcohol dependence is focused on detoxification, enhancing motivation to change, and coping strategies for the management of emotional distress and temptation to drink. The aims of the present study were to investigate 1) changes over time in motivation to change, anxiety, and depression in individuals undergoing residential rehabilitation treatment for alcohol addiction, and 2) which pretreatment factors are associated with posttreatment temptation to drink. We assessed 432 patients diagnosed with alcohol dependence based on the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition, Text Revision) consecutively recruited from seven residential rehabilitation centers in Northern Italy. Patients were assessed by means of self-report questionnaires at the beginning of rehabilitation (pretreatment) and before their hospital discharge (posttreatment) regarding motivation to change and self-efficacy (motivation assessment of change - alcoholism version), readiness to change and temptation to drink (visual analog scales), and depression and anxiety (cognitive behavioral assessment - outcome evaluation). Results showed an overall improvement in motivation to change and a significant reduction over time in depression and anxiety levels for the total sample, particularly patients with low baseline level of temptation to drink. Multivariate linear regression analysis revealed that significant predictors of posttreatment temptation to drink were polysubstance dependence ( p <0.001), readiness to change ( p =0.01), and self-efficacy ( p =0.05). Inpatients' rehabilitation for alcohol dependence is associated with an overall improvement in motivation to change and a significant reduction of psychological distress. Treatments for alcohol-dependent patients should focus on motivation to change, negative moods, and relapse prevention strategies for the management of craving.

Motivation to change and posttreatment temptation to drink: a multicenter study among alcohol-dependent patients

PubMed Central

Fiabane, Elena; Ottonello, Marcella; Zavan, Valeria; Pistarini, Caterina; Giorgi, Ines

2017-01-01

Background An inpatient 28-day rehabilitation program for alcohol dependence is focused on detoxification, enhancing motivation to change, and coping strategies for the management of emotional distress and temptation to drink. The aims of the present study were to investigate 1) changes over time in motivation to change, anxiety, and depression in individuals undergoing residential rehabilitation treatment for alcohol addiction, and 2) which pretreatment factors are associated with posttreatment temptation to drink. Methods We assessed 432 patients diagnosed with alcohol dependence based on the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition, Text Revision) consecutively recruited from seven residential rehabilitation centers in Northern Italy. Patients were assessed by means of self-report questionnaires at the beginning of rehabilitation (pretreatment) and before their hospital discharge (posttreatment) regarding motivation to change and self-efficacy (motivation assessment of change – alcoholism version), readiness to change and temptation to drink (visual analog scales), and depression and anxiety (cognitive behavioral assessment – outcome evaluation). Results Results showed an overall improvement in motivation to change and a significant reduction over time in depression and anxiety levels for the total sample, particularly patients with low baseline level of temptation to drink. Multivariate linear regression analysis revealed that significant predictors of posttreatment temptation to drink were polysubstance dependence (p<0.001), readiness to change (p=0.01), and self-efficacy (p=0.05). Conclusion Inpatients’ rehabilitation for alcohol dependence is associated with an overall improvement in motivation to change and a significant reduction of psychological distress. Treatments for alcohol-dependent patients should focus on motivation to change, negative moods, and relapse prevention strategies for the management of craving. PMID:29042778

Mid-Infrared Lifetime Imaging for Viability Evaluation of Lettuce Seeds Based on Time-Dependent Thermal Decay Characterization

PubMed Central

Kim, Ghiseok; Kim, Geon Hee; Ahn, Chi-Kook; Yoo, Yoonkyu; Cho, Byoung-Kwan

2013-01-01

An infrared lifetime thermal imaging technique for the measurement of lettuce seed viability was evaluated. Thermal emission signals from mid-infrared images of healthy seeds and seeds aged for 24, 48, and 72 h were obtained and reconstructed using regression analysis. The emission signals were fitted with a two-term exponential model that had two amplitudes and two time variables as lifetime parameters. The lifetime thermal decay parameters were significantly different for seeds with different aging times. Single-seed viability was visualized using thermal lifetime images constructed from the calculated lifetime parameter values. The time-dependent thermal signal decay characteristics, along with the decay amplitude and delay time images, can be used to distinguish aged lettuce seeds from normal seeds. PMID:23529120

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

Ha, Jung Min; Yun, Sung Ji; Kim, Young Whan

Mammalian target of rapamycin complex (mTORC) regulates various cellular processes including proliferation, growth, migration and differentiation. In this study, we showed that mTORC1 regulates platelet-derived growth factor (PDGF)-induced phenotypic conversion of vascular smooth muscle cells (VSMCs). Stimulation of contractile VSMCs with PDGF significantly reduced the expression of contractile marker proteins in a time- and dose-dependent manner. In addition, angiotensin II (AngII)-induced contraction of VSMCs was completely blocked by the stimulation of VSMCs with PDGF. PDGF-dependent suppression of VSMC marker gene expression was significantly blocked by inhibition of phosphatidylinositol 3-kinase (PI3K), extracellular signal-regulated kinase (ERK), and mTOR whereas inhibition of p38more » MAPK had no effect. In particular, inhibition of mTORC1 by rapamycin or by silencing of Raptor significantly blocked the PDGF-dependent phenotypic change of VSMCs whereas silencing of Rictor had no effect. In addition, loss of AngII-dependent contraction by PDGF was significantly retained by silencing of Raptor. Inhibition of mTORC1 by rapamycin or by silencing of Raptor significantly blocked PDGF-induced proliferation of VSMCs. Taken together, we suggest that mTORC1 plays an essential role in PDGF-dependent phenotypic changes of VSMCs. - Graphical abstract: Regulation of VSMC phenotype by PDGF-dependent activation of mTORC1. - Highlights: • The expression of contractile marker proteins was reduced by PDGF stimulation. • PDGF-dependent phenotypic conversion of VSMCs was blocked by inhibition of mTOR. • PDGF-induced proliferation of VSMCs was attenuated by inhibition of mTORC1. • mTORC1 plays a critical role in PDGF-dependent phenotypic conversion of VSMCs.« less

Effects of yohimbine and drug cues on impulsivity and attention in cocaine-dependent men and women and sex-matched controls.

PubMed

Moran-Santa Maria, M M; Baker, N L; McRae-Clark, A L; Prisciandaro, J J; Brady, K T

2016-05-01

Deficits in executive function have been associated with risk for relapse. Data from previous studies suggest that relapse may be triggered by stress and drug-paired cues and that there are significant sex differences in the magnitude of these responses. The aim of this study was to examine the impact of the pharmacological stressor and alpha-2 adrenergic receptor antagonist yohimbine and cocaine cues on executive function in cocaine-dependent men and women. In a double-blind placebo controlled cross-over study, cocaine-dependent men (n=12), cocaine-dependent women (n=27), control men (n=31) and control women (n=25) received either yohimbine or placebo prior to two cocaine cue exposure sessions. Participants performed the Connors' Continuous Performance Test II prior to medication/placebo administration and immediately after each cue exposure session Healthy controls had a significant increase in commission errors under the yohimbine condition [RR (95% CI)=1.1 (1.0-1.3), χ(2)1=2.0, p=0.050]. Cocaine-dependent individuals exhibited a significant decrease in omission errors under the yohimbine condition [RR (95% CI)=0.6 (0.4-0.8), χ(2)1=8.6, p=0.003]. Cocaine-dependent women had more omission errors as compared to cocaine-dependent men regardless of treatment [RR (95% CI)=7.2 (3.6-14.7), χ(2)1=30.1, p<0.001]. Cocaine-dependent women exhibited a slower hit reaction time as compared to cocaine-dependent men [Female 354 ± 13 vs. Male 415 ± 14; t89=2.6, p=0.012]. These data add to a growing literature demonstrating significant sex differences in behaviors associated with relapse in cocaine-dependent individuals. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Skeletal muscle tensile strain dependence: hyperviscoelastic nonlinearity

PubMed Central

Wheatley, Benjamin B; Morrow, Duane A; Odegard, Gregory M; Kaufman, Kenton R; Donahue, Tammy L Haut

2015-01-01

Introduction Computational modeling of skeletal muscle requires characterization at the tissue level. While most skeletal muscle studies focus on hyperelasticity, the goal of this study was to examine and model the nonlinear behavior of both time-independent and time-dependent properties of skeletal muscle as a function of strain. Materials and Methods Nine tibialis anterior muscles from New Zealand White rabbits were subject to five consecutive stress relaxation cycles of roughly 3% strain. Individual relaxation steps were fit with a three-term linear Prony series. Prony series coefficients and relaxation ratio were assessed for strain dependence using a general linear statistical model. A fully nonlinear constitutive model was employed to capture the strain dependence of both the viscoelastic and instantaneous components. Results Instantaneous modulus (p<0.0005) and mid-range relaxation (p<0.0005) increased significantly with strain level, while relaxation at longer time periods decreased with strain (p<0.0005). Time constants and overall relaxation ratio did not change with strain level (p>0.1). Additionally, the fully nonlinear hyperviscoelastic constitutive model provided an excellent fit to experimental data, while other models which included linear components failed to capture muscle function as accurately. Conclusions Material properties of skeletal muscle are strain-dependent at the tissue level. This strain dependence can be included in computational models of skeletal muscle performance with a fully nonlinear hyperviscoelastic model. PMID:26409235

A hazard rate analysis of fertility using duration data from Malaysia.

PubMed

Chang, C

1988-01-01

Data from the Malaysia Fertility and Family Planning Survey (MFLS) of 1974 were used to investigate the effects of biological and socioeconomic variables on fertility based on the hazard rate model. Another study objective was to investigate the robustness of the findings of Trussell et al. (1985) by comparing the findings of this study with theirs. The hazard rate of conception for the jth fecundable spell of the ith woman, hij, is determined by duration dependence, tij, measured by the waiting time to conception; unmeasured heterogeneity (HETi; the time-invariant variables, Yi (race, cohort, education, age at marriage); and time-varying variables, Xij (age, parity, opportunity cost, income, child mortality, child sex composition). In this study, all the time-varying variables were constant over a spell. An asymptotic X2 test for the equality of constant hazard rates across birth orders, allowing time-invariant variables and heterogeneity, showed the importance of time-varying variables and duration dependence. Under the assumption of fixed effects heterogeneity and the Weibull distribution for the duration of waiting time to conception, the empirical results revealed a negative parity effect, a negative impact from male children, and a positive effect from child mortality on the hazard rate of conception. The estimates of step functions for the hazard rate of conception showed parity-dependent fertility control, evidence of heterogeneity, and the possibility of nonmonotonic duration dependence. In a hazard rate model with piecewise-linear-segment duration dependence, the socioeconomic variables such as cohort, child mortality, income, and race had significant effects, after controlling for the length of the preceding birth. The duration dependence was consistant with the common finding, i.e., first increasing and then decreasing at a slow rate. The effects of education and opportunity cost on fertility were insignificant.

Estimation of Coda Wave Attenuation in Northern Morocco

NASA Astrophysics Data System (ADS)

Boulanouar, Abderrahim; Moudnib, Lahcen El; Padhy, Simanchal; Harnafi, Mimoun; Villaseñor, Antonio; Gallart, Josep; Pazos, Antonio; Rahmouni, Abdelaali; Boukalouch, Mohamed; Sebbani, Jamal

2018-03-01

We studied the attenuation of coda waves and its frequency and lapse-time dependence in northern Morocco. We analysed coda waves of 66 earthquakes recorded in this region during 2008 for four lapse time windows of length 30, 40, 50, and 60 s, and at five frequency bands with central frequency in the range of 0.75-12 Hz. We determined the frequency dependent Q c relation for the horizontal (NS and EW) and vertical (Z) component seismograms. We analyzed three-component broadband seismograms of 66 local earthquakes for determining coda-Q based on the single back-scattering model. The Q c values show strong frequency dependence in 1.5-12 Hz that is related to high degree of heterogeneity of the medium. The lapse time dependence of Q c shows that Q 0 ( Q c at 1 Hz) significantly increases with lapse time that is related to the depth dependence of attenuation and hence of the level of heterogeneity of the medium. The average frequency-dependent Q c( f) values are Qc = (143.75 ± 1.09)f^{(0.864 ± 0.006)}, Qc = (149.12 ± 1.08)f^{(0.85 ± 0.005)} and Qc = (140.42 ± 1.81)f^{(0.902 ± 0.004)} for the vertical, north-south and east-west components of motion, respectively. The frequency-dependent Q c(f) relations are useful for evaluating source parameters (Singh et al. 2001), which are the key inputs for seismic hazard assessment of the region.

Effect of sealer coating and storage methods on the surface roughness of soft liners.

PubMed

Usta Kutlu, Ilknur; Yanikoğlu, Nuran Dinckal; Kul, Esra; Duymuş, Zeynep Yesïl; Sağsöz, Nurdan Polat

2016-03-01

A soft lining is applied under a removable prosthesis for various reasons. The porosity of the lining material may increase colonization by microorganisms and cause tissue inflammation. The purpose of this in vitro study was to evaluate the effect of sealer coating on the surface roughness of soft lining materials under 4 different conditions. A total of 125 specimens were prepared. One high-temperature silicone-based soft lining material and 2 room-temperature-polymerized soft lining materials (1 silicone-based and 1 methacrylate-based) were used. Twenty-five specimens of each room-temperature soft lining material were coated with 2 layers of surface sealer. Additionally, 5 specimens of each material were stored in either distilled water, Coca-Cola, denture cleanser, saliva, or air. The surface roughness was measured at baseline and after 1, 7, 14, and 28 days. Surface roughness values were analyzed with repeated measures analysis of variance, and the Bonferroni multiple comparison test was performed using time-dependent groups and storage methods. In the time-dependent groups, methacrylate-based sealer-coated soft liners exhibited a significant increase in roughness (1.74-2.09 μm, P<.001), and silicone-based sealer-coated soft liners exhibited a decrease in roughness, but it was not significant (2.16-2.02 μm, P>.05). Therefore, the sealer coating was not effective in reducing surface roughness. Among the time-dependent storage methods, the denture cleanser exhibited an almost significant increase in roughness (1.83-1.99 μm, P=.054). Coca-Cola and artificial saliva did not show a significant difference (P>.05). However, a significant decrease in roughness was found with distilled water (P=.02) and air (P<.001). Statistically significant differences in surface roughness were found among the different types of soft liners. The sealer coating had no significant effect, and denture cleanser slightly increased the surface roughness. Contrary to expectations, the roughness did not increase in all groups over time. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Assessing the Potential Consequences of Subsurface Bioremediation: Fe-oxide Bioreductive Processes and the Propensity for Contaminant-colloid Co-transport and Media Structural Breakdown

DTIC Science & Technology

2017-05-12

were resolved by a technical approach that included three well-integrated experimental tasks follows: Task A: Quantify the impact of time- dependent ...aggregate breakdown and colloid dispersion depending on the extent of Fe(III) reduction and altered the pore structure and chemical reactivity of the porous...have significant effect on the transport of molecular and colloidal tracers (but not on the ionic tracer Br-) and colloid generation depending on

Are Dropout and Degree Completion in Doctoral Study Significantly Dependent on Type of Financial Support and Field of Research?

ERIC Educational Resources Information Center

van der Haert, Margaux; Arias Ortiz, Elena; Emplit, Philippe; Halloin, Véronique; Dehon, Catherine

2014-01-01

In this article, the determinants of "time to dropout" from doctoral studies and "time to PhD completion" are studied using a discrete-time competing risks survival analysis for a sample of 3092 doctoral candidates from the Université libre de Bruxelles. Not surprisingly, results show that students supported with research…

Time-evolving collagen-like structural fibers in soft tissues: biaxial loading and spherical inflation

NASA Astrophysics Data System (ADS)

Topol, Heiko; Demirkoparan, Hasan; Pence, Thomas J.; Wineman, Alan

2017-02-01

This work considers a previously developed constitutive theory for the time dependent mechanical response of fibrous soft tissue resulting from the time dependent remodeling of a collagen fiber network that is embedded in a ground substance matrix. The matrix is taken to be an incompressible nonlinear elastic solid. The remodeling process consists of the continual dissolution of existing fibers and the creation of new fibers. Motivated by experimental reports on the enzyme degradation of collagen fibers, the remodeling is governed by first order chemical kinetics such that the dissolution rate is dependent upon the fiber stretch. The resulting time dependent mechanical response is sensitive to the natural configuration of the fibers when they are created, and different assumptions on the nature of the fiber's stress free state are considered here. The response under biaxial loading, a type of loading that has particular significance for the characterization of biological materials, is studied. The inflation of a spherical membrane is then analyzed in terms of the equal biaxial stretch that occurs in the membrane approximation. Different assumptions on the natural configuration of the fibers, combined with their time dependent dissolution and reforming, are shown to emulate alternative forms of creep and relaxation response. This formal similarity to viscoelastic phenomena occurs even though the underlying mechanisms are fundamentally different from the mechanism of macromolecular reconfiguration that one typically associates with viscoelastic response.

Extreme late chronotypes and social jetlag challenged by Antarctic conditions in a population of university students from Uruguay.

PubMed

Tassino, Bettina; Horta, Stefany; Santana, Noelia; Levandovski, Rosa; Silva, Ana

2016-01-01

In humans, a person's chronotype depends on environmental cues and on individual characteristics, with late chronotypes prevailing in youth. Social jetlag (SJL), the misalignment between an individual׳s biological clock and social time, is higher in late chronotypes. Strong SJL is expected in Uruguayan university students with morning class schedules and very late entertainment activities. Sleep disorders have been reported in Antarctic inhabitants, that might be a response to the extreme environment or to the strictness of Antarctic life. We evaluated, for the first time in Uruguay, the chronotypes and SJL of 17 undergraduate students of the First Uruguayan Summer School on Antarctic Research, using Munich Chronotype Questionnaire (MCTQ) and sleep logs (SL) recorded during 3 phases: pre-Antarctic, Antarctic, and post-Antarctic. The midsleep point of free days corrected for sleep debt on work days (MSFsc,) was used as proxy of individuals' chronotype, whose values (around 6 a.m.) are the latest ever reported. We found a SJL of around 2 h in average, which correlated positively with MSFsc, confirming that late chronotypes generate a higher sleep debt during weekdays. Midsleep point and sleep duration significantly decreased between pre-Antarctic and Antarctic phases, and sleep duration rebounded to significant higher values in the post-Antarctic phase. Waking time, but not sleep onset time, significantly varied among phases. This evidence suggests that sleep schedules more likely depended on the social agenda than on the environmental light-dark shifts. High motivation of students towards Antarctic activities likely induced a subjective perception of welfare non-dependent on sleep duration.

Time-dependent irisin concentration changes in patients affected by overt hypothyroidism.

PubMed

Zybek-Kocik, Ariadna; Sawicka-Gutaj, Nadia; Wrotkowska, Elżbieta; Sowiński, Jerzy; Ruchała, Marek

2016-01-01

Irisin, a cleaved and secreted part of the transmembrane protein FNDC5, is a recently discovered adipo-myokine that is said to have a significant influence on body metabolism. Changes in thyrometabolic state may also alter the serum irisin level. Since already reported data are not fully consistent, the aim of the present research is to evaluate the time-dependent changes in serum irisin level in patients affected by overt hypothyroidism. The study involved 36 subjects - two groups of 12 patients with long-lasting (AITD) and short-term (TC) overt hypothyroidism, and a control group (CG) of 12 subjects, matched for age and gender. Serum irisin level, thyrometabolic state, creatine kinase (CK - muscle damage marker), glucose, and insulin concentration were assessed and compared between groups. The irisin level was significantly lower in AITD than in TC and CG (p = 0.02; p < 0.01; respectively) patients, with no statistical difference between TC and CG (p > 0.05). There was no significant difference between free triiodothyronine and free thyroxine levels in AITD and TC patients (p > 0.05). CK concentration was significantly higher in AITD than in CG patients (p < 0.01) with no difference between AITD and TC patients (p > 0.05) as well as TC and CG patients (p > 0.05). Additionally, the CK level negatively correlated with the irisin level (r = -0.58; p < 0.01). In conclusion, the irisin concentration changes during thyroid function impairment may be time-dependent. Patients with prolonged hypothyroidism have lower irisin levels that those with short-term disorder. (Endokrynol Pol 2016; 67 (5): 476-480).

Increased serum IL-6 level time-dependently regulates hyperalgesia and spinal mu opioid receptor expression during CFA-induced arthritis

PubMed Central

Tekieh, E.; Zaringhalam, Jalal; Manaheji, H.; Maghsoudi, N.; Alani, B.; Zardooz, H.

2011-01-01

Interleukin (IL)-6 is known to cause pro- and anti-inflammatory effects during different stages of inflammation. Recent therapeutic investigations have focused on treatment of various inflammatory disorders with anti-cytokine substances. As a result, the aim of this study was to further elucidate the influence of IL-6 in hyperalgesia and edema during different stages of Complete Freund's Adjuvant (CFA)-induced arthritis (AA) in male Wistar rats. AA was induced by a single subcutaneous injection of CFA into the rats' hindpaw. Anti-IL-6 was administered either daily or weekly during the 21 days of study. Spinal mu opioid receptor (mOR) expression was detected by Western blotting. Daily and weekly treatment with an anti-IL-6 antibody significantly decreased paw edema in the AA group compared to the AA control group. Additionally, daily and weekly anti-IL-6 administration significantly reduced hyperalgesia on day 7 in the AA group compared to the AA control group; however, there were significant increases in hyperalgesia in the antibody-treated group on days 14 and 21 compared to the AA control group. IL-6 antibody-induced increases in hyperalgesia on the 14th and 21st days after CFA injection correlated with a time-dependent, significant reduction in spinal mOR expression during anti-IL-6 treatment. Our study confirmed the important time-dependent relationship between serum IL-6 levels and hyperalgesia during AA. These results suggest that the stages of inflammation in AA must be considered for anti-hyperalgesic and anti-inflammatory interventions via anti-IL-6 antibody treatment. PMID:27857662

Increased serum IL-6 level time-dependently regulates hyperalgesia and spinal mu opioid receptor expression during CFA-induced arthritis.

PubMed

Tekieh, E; Zaringhalam, Jalal; Manaheji, H; Maghsoudi, N; Alani, B; Zardooz, H

2011-01-01

Interleukin (IL)-6 is known to cause pro- and anti-inflammatory effects during different stages of inflammation. Recent therapeutic investigations have focused on treatment of various inflammatory disorders with anti-cytokine substances. As a result, the aim of this study was to further elucidate the influence of IL-6 in hyperalgesia and edema during different stages of Complete Freund's Adjuvant (CFA)-induced arthritis (AA) in male Wistar rats. AA was induced by a single subcutaneous injection of CFA into the rats' hindpaw. Anti-IL-6 was administered either daily or weekly during the 21 days of study. Spinal mu opioid receptor (mOR) expression was detected by Western blotting. Daily and weekly treatment with an anti-IL-6 antibody significantly decreased paw edema in the AA group compared to the AA control group. Additionally, daily and weekly anti-IL-6 administration significantly reduced hyperalgesia on day 7 in the AA group compared to the AA control group; however, there were significant increases in hyperalgesia in the antibody-treated group on days 14 and 21 compared to the AA control group. IL-6 antibody-induced increases in hyperalgesia on the 14 th and 21 st days after CFA injection correlated with a time-dependent, significant reduction in spinal mOR expression during anti-IL-6 treatment. Our study confirmed the important time-dependent relationship between serum IL-6 levels and hyperalgesia during AA. These results suggest that the stages of inflammation in AA must be considered for anti-hyperalgesic and anti-inflammatory interventions via anti-IL-6 antibody treatment.

SU-E-T-222: Computational Optimization of Monte Carlo Simulation On 4D Treatment Planning Using the Cloud Computing Technology

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

Chow, J

Purpose: This study evaluated the efficiency of 4D lung radiation treatment planning using Monte Carlo simulation on the cloud. The EGSnrc Monte Carlo code was used in dose calculation on the 4D-CT image set. Methods: 4D lung radiation treatment plan was created by the DOSCTP linked to the cloud, based on the Amazon elastic compute cloud platform. Dose calculation was carried out by Monte Carlo simulation on the 4D-CT image set on the cloud, and results were sent to the FFD4D image deformation program for dose reconstruction. The dependence of computing time for treatment plan on the number of computemore » node was optimized with variations of the number of CT image set in the breathing cycle and dose reconstruction time of the FFD4D. Results: It is found that the dependence of computing time on the number of compute node was affected by the diminishing return of the number of node used in Monte Carlo simulation. Moreover, the performance of the 4D treatment planning could be optimized by using smaller than 10 compute nodes on the cloud. The effects of the number of image set and dose reconstruction time on the dependence of computing time on the number of node were not significant, as more than 15 compute nodes were used in Monte Carlo simulations. Conclusion: The issue of long computing time in 4D treatment plan, requiring Monte Carlo dose calculations in all CT image sets in the breathing cycle, can be solved using the cloud computing technology. It is concluded that the optimized number of compute node selected in simulation should be between 5 and 15, as the dependence of computing time on the number of node is significant.« less

Heterogeneity of human adipose blood flow

PubMed Central

Levitt, David G

2007-01-01

Background The long time pharmacokinetics of highly lipid soluble compounds is dominated by blood-adipose tissue exchange and depends on the magnitude and heterogeneity of adipose blood flow. Because the adipose tissue is an infinite sink at short times (hours), the kinetics must be followed for days in order to determine if the adipose perfusion is heterogeneous. The purpose of this paper is to quantitate human adipose blood flow heterogeneity and determine its importance for human pharmacokinetics. Methods The heterogeneity was determined using a physiologically based pharmacokinetic model (PBPK) to describe the 6 day volatile anesthetic data previously published by Yasuda et. al. The analysis uses the freely available software PKQuest and incorporates perfusion-ventilation mismatch and time dependent parameters that varied from the anesthetized to the ambulatory period. This heterogeneous adipose perfusion PBPK model was then tested by applying it to the previously published cannabidiol data of Ohlsson et. al. and the cannabinol data of Johansson et. al. Results The volatile anesthetic kinetics at early times have only a weak dependence on adipose blood flow while at long times the pharmacokinetics are dominated by the adipose flow and are independent of muscle blood flow. At least 2 adipose compartments with different perfusion rates (0.074 and 0.014 l/kg/min) were needed to describe the anesthetic data. This heterogeneous adipose PBPK model also provided a good fit to the cannabinol data. Conclusion Human adipose blood flow is markedly heterogeneous, varying by at least 5 fold. This heterogeneity significantly influences the long time pharmacokinetics of the volatile anesthetics and tetrahydrocannabinol. In contrast, using this same PBPK model it can be shown that the long time pharmacokinetics of the persistent lipophilic compounds (dioxins, PCBs) do not depend on adipose blood flow. The ability of the same PBPK model to describe both the anesthetic and cannabinol kinetics provides direct qualitative evidence that their kinetics are flow limited and that there is no significant adipose tissue diffusion limitation. PMID:17239252

[Effect of smoking on weight and cardiopulmonary capacities in young athletes].

PubMed

Packa-Tchissambou, B; Oniangue, R; Massamba, A; Babela, J R; Makanga, M; Senga, P

2001-01-01

The aim of the study was to determine wether smokers practising sports have reduced weight, if recuperation time after moderate exercise and maximal aerobic power were lowered. Thousand young soldiers [50 smokers (S), 50 no smokers (NS)] averaging 24 years in age were studied. The subjects performed to exhaustion on Ruffier test, then a maximal exercise with Cooper test. Several biometrical and physiological parameters were evaluated: weight (W), percent of body fat (PBF), body mass index (BMI), maximal oxygen uptake (VO2 max) and recuperation index (RI). Kinetics of heart rate (HR) were studied for 7 min considering time constant (1 min) and delay for recovery. The smokers showed significant differences for W (p < 0.001), PBF (p < 0.05), VO2 max (p < 0.01) and recuperation index (p < 0.001). Maximal aerobic power were 45.8 +/- 2.7 and 50.3 +/- 3.2 ml/kg/min for S and NS, and RI were 7.5 +/- 0.9 (S) and 5.0 +/- 1 (NS). figure 1 shows that HR recovery of S has generally two components: the first was fast, the second was a slone none. The smokers who presented a great dependence to tobacco smoking had a significant lower RI (p < 0.001) as those subjects with little tobacco dependence (Table 5). The smokers had lower values of VO2 max, and there exists a tobacco dependence difference. Recuperation time for the aerobically well trained S subjects was more rapid during the lactic phase. Note that correlations obtained between the VO2 max and RI were significant (r = - 0.788; p < 0.05). The smokers and no smokers differences are discussed with reference to nicotinemia effects and the sympathetic-parasympathetic unbatance of influences. The comparison of smokers groups concerning cardiovascular data led to suppose that there exists a tobacco dependence difference in regards of the catecholaminergic sensitivity. In conclusion, this study showed that smoker practising a physical activity have a reduced weight, a higher recuperation time and an anaerobic limitation influenced by the state of tobacco dependence.

Time distributions of solar energetic particle events: Are SEPEs really random?

NASA Astrophysics Data System (ADS)

Jiggens, P. T. A.; Gabriel, S. B.

2009-10-01

Solar energetic particle events (SEPEs) can exhibit flux increases of several orders of magnitude over background levels and have always been considered to be random in nature in statistical models with no dependence of any one event on the occurrence of previous events. We examine whether this assumption of randomness in time is correct. Engineering modeling of SEPEs is important to enable reliable and efficient design of both Earth-orbiting and interplanetary spacecraft and future manned missions to Mars and the Moon. All existing engineering models assume that the frequency of SEPEs follows a Poisson process. We present analysis of the event waiting times using alternative distributions described by Lévy and time-dependent Poisson processes and compared these with the usual Poisson distribution. The results show significant deviation from a Poisson process and indicate that the underlying physical processes might be more closely related to a Lévy-type process, suggesting that there is some inherent “memory” in the system. Inherent Poisson assumptions of stationarity and event independence are investigated, and it appears that they do not hold and can be dependent upon the event definition used. SEPEs appear to have some memory indicating that events are not completely random with activity levels varying even during solar active periods and are characterized by clusters of events. This could have significant ramifications for engineering models of the SEP environment, and it is recommended that current statistical engineering models of the SEP environment should be modified to incorporate long-term event dependency and short-term system memory.

Naltrexone versus acamprosate: one year follow-up of alcohol dependence treatment.

PubMed

Rubio, G; Jiménez-Arriero, M A; Ponce, G; Palomo, T

2001-01-01

Naltrexone and acamprosate reduce relapse in alcohol dependence. They have not yet been compared in a published trial. The aim of this study was to compare the efficacy of these compounds in conditions similar to those in routine clinical practice. Random allocation to a year of treatment with naltrexone (50 mg/day) or acamprosate (1665-1998 mg/day) was made in 157 recently detoxified alcohol-dependent men with moderate dependence (evaluated using the Addictions Severity Index and Severity of Alcohol Dependence Scale). All were patients whom a member of the family would accompany regularly to appointments. Alcohol consumption, craving and adverse events were recorded weekly for the first 3 months, and then bi-weekly, by the treating psychiatrist who was not blinded. At 3-monthly intervals, investigators who were blinded to the treatment documented patients' alcohol consumption based on patients' accounts, information given by the psychiatrists when necessary, and reports from patients' families. Serum gamma-glutamyltransferase (GGT) was also measured. Efforts were made to sustain the blindness of the investigators. The same investigator did not assess the same patient twice. The integrity of the blindness was not checked. There was no difference between treatments in mean time to first drink (naltrexone 44 days, acamprosate 39 days) but the time to first relapse (five or more drinks in a day) was 63 days (naltrexone) versus 42 days (acamprosate) (P = 0.02). At the end of 1 year, 41% receiving naltrexone and 17% receiving acamprosate had not relapsed (P = 0.0009). The cumulative number of days of abstinence was significantly greater, and the number of drinks consumed at one time and severity of craving were significantly less, in the naltrexone group compared to the acamprosate group, as was the percentage of heavy drinking days (P = 0.038). More patients in the acamprosate than the naltrexone group were commenced on disulfiram during the study. Naltrexone patients attended significantly more group therapy sessions, though this could not explain their better outcome. There were non-significant trends for the naltrexone group to comply better with medication, to stay in the study longer, and to show greater improvement over baseline in serum GGT.

Three-dimensional particle-particle simulations: Dependence of relaxation time on plasma parameter

NASA Astrophysics Data System (ADS)

Zhao, Yinjian

2018-05-01

A particle-particle simulation model is applied to investigate the dependence of the relaxation time on the plasma parameter in a three-dimensional unmagnetized plasma. It is found that the relaxation time increases linearly as the plasma parameter increases within the range of the plasma parameter from 2 to 10; when the plasma parameter equals 2, the relaxation time is independent of the total number of particles, but when the plasma parameter equals 10, the relaxation time slightly increases as the total number of particles increases, which indicates the transition of a plasma from collisional to collisionless. In addition, ions with initial Maxwell-Boltzmann (MB) distribution are found to stay in the MB distribution during the whole simulation time, and the mass of ions does not significantly affect the relaxation time of electrons. This work also shows the feasibility of the particle-particle model when using GPU parallel computing techniques.

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

Dustin Popp; Zander Mausolff; Sedat Goluoglu

We are proposing to use the code, TDKENO, to model TREAT. TDKENO solves the time dependent, three dimensional Boltzmann transport equation with explicit representation of delayed neutrons. Instead of directly integrating this equation, the neutron flux is factored into two components – a rapidly varying amplitude equation and a slowly varying shape equation and each is solved separately on different time scales. The shape equation is solved using the 3D Monte Carlo transport code KENO, from Oak Ridge National Laboratory’s SCALE code package. Using the Monte Carlo method to solve the shape equation is still computationally intensive, but the operationmore » is only performed when needed. The amplitude equation is solved deterministically and frequently, so the solution gives an accurate time-dependent solution without having to repeatedly We have modified TDKENO to incorporate KENO-VI so that we may accurately represent the geometries within TREAT. This paper explains the motivation behind using generalized geometry, and provides the results of our modifications. TDKENO uses the Improved Quasi-Static method to accomplish this. In this method, the neutron flux is factored into two components. One component is a purely time-dependent and rapidly varying amplitude function, which is solved deterministically and very frequently (small time steps). The other is a slowly varying flux shape function that weakly depends on time and is only solved when needed (significantly larger time steps).« less

Regulation of synthesis and activity of NAD(+)-dependent 15-hydroxy-prostaglandin dehydrogenase (15-PGDH) by dexamethasone and phorbol ester in human erythroleukemia (HEL) cells

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

Xun, C.Q.; Ensor, C.M.; Tai, H.H.

1991-06-28

Dexamethasone stimulated 15-PGDH activity in HEL cells in a time and concentration dependent manner. Increase in 15-PGDH activity by dexamethasone was found to be accompanied by an increase in enzyme synthesis as revealed by Western blot and (35S)methionine labeling studies. In addition to dexamethasone, other anti-inflammatory steroids also increased 15-PGDH activity in the order of their glucocorticoid activity. Among sex steroids only progesterone increased significantly 15-PGDH activity. 12-0-Tetradecanoylphorbol-13-acetate (TPA) also induced the synthesis of 15-PGDH but inhibited the enzyme activity. It appears that TPA caused a time dependent inactivation of 15-PGDH by a protein kinase C mediated mechanism.

Empirical study of the dependence of the results of multivariable flexible survival analyses on model selection strategy.

PubMed

Binquet, C; Abrahamowicz, M; Mahboubi, A; Jooste, V; Faivre, J; Bonithon-Kopp, C; Quantin, C

2008-12-30

Flexible survival models, which avoid assumptions about hazards proportionality (PH) or linearity of continuous covariates effects, bring the issues of model selection to a new level of complexity. Each 'candidate covariate' requires inter-dependent decisions regarding (i) its inclusion in the model, and representation of its effects on the log hazard as (ii) either constant over time or time-dependent (TD) and, for continuous covariates, (iii) either loglinear or non-loglinear (NL). Moreover, 'optimal' decisions for one covariate depend on the decisions regarding others. Thus, some efficient model-building strategy is necessary.We carried out an empirical study of the impact of the model selection strategy on the estimates obtained in flexible multivariable survival analyses of prognostic factors for mortality in 273 gastric cancer patients. We used 10 different strategies to select alternative multivariable parametric as well as spline-based models, allowing flexible modeling of non-parametric (TD and/or NL) effects. We employed 5-fold cross-validation to compare the predictive ability of alternative models.All flexible models indicated significant non-linearity and changes over time in the effect of age at diagnosis. Conventional 'parametric' models suggested the lack of period effect, whereas more flexible strategies indicated a significant NL effect. Cross-validation confirmed that flexible models predicted better mortality. The resulting differences in the 'final model' selected by various strategies had also impact on the risk prediction for individual subjects.Overall, our analyses underline (a) the importance of accounting for significant non-parametric effects of covariates and (b) the need for developing accurate model selection strategies for flexible survival analyses. Copyright 2008 John Wiley & Sons, Ltd.

Effect of Time-Dependent Sorption on the Dissipation of Water-Extractable Pesticides in Soils.

PubMed

Motoki, Yutaka; Iwafune, Takashi; Seike, Nobuyasu; Inao, Keiya; Otani, Takashi

2016-06-08

The dissipation behavior of water-extractable pesticides in soils is important when assessing the phytoavailability of pesticides in soils. This process is less understood than pesticide extraction with organic solvents. To elucidate the dissipation behavior of water-extractable pesticides in soils, we conducted an incubation study using 27 pesticides and five Japanese soils. The rate of decrease of the level of pesticides in water extracts was faster in soils than that of total extracts (water extracts and acetone extracts). This suggests that time-dependent sorption contributed to the difference in the dissipation between the pesticides in water and total extracts from soils. Increased apparent sorption coefficients (Kd,app) with time were positively and significantly correlated with Kd,app values of a 0 day incubation [Kd,app(t0)]. This empirical relationship suggests that Kd,app(t0) values can predict the time-dependent increase in Kd,app and the dissipation of water-extractable pesticides in soils.

Nonequilibrium Steady State Generated by a Moving Defect: The Supersonic Threshold

NASA Astrophysics Data System (ADS)

Bastianello, Alvise; De Luca, Andrea

2018-02-01

We consider the dynamics of a system of free fermions on a 1D lattice in the presence of a defect moving at constant velocity. The defect has the form of a localized time-dependent variation of the chemical potential and induces at long times a nonequilibrium steady state (NESS), which spreads around the defect. We present a general formulation that allows recasting the time-dependent protocol in a scattering problem on a static potential. We obtain a complete characterization of the NESS. In particular, we show a strong dependence on the defect velocity and the existence of a sharp threshold when such velocity exceeds the speed of sound. Beyond this value, the NESS is not produced and, remarkably, the defect travels without significantly perturbing the system. We present an exact solution for a δ -like defect traveling with an arbitrary velocity and we develop a semiclassical approximation that provides accurate results for smooth defects.

Local time dependence of turbulent magnetic fields in Saturn's magnetodisc

NASA Astrophysics Data System (ADS)

Kaminker, V.; Delamere, P. A.; Ng, C. S.; Dennis, T.; Otto, A.; Ma, X.

2017-04-01

Net plasma transport in magnetodiscs around giant planets is outward. Observations of plasma temperature have shown that the expanding plasma is heating nonadiabatically during this process. Turbulence has been suggested as a source of heating. However, the mechanism and distribution of magnetic fluctuations in giant magnetospheres are poorly understood. In this study we attempt to quantify the radial and local time dependence of fluctuating magnetic field signatures that are suggestive of turbulence, quantifying the fluctuations in terms of a plasma heating rate density. In addition, the inferred heating rate density is correlated with magnetic field configurations that include azimuthal bend forward/back and magnitude of the equatorial normal component of magnetic field relative to the dipole. We find a significant local time dependence in magnetic fluctuations that is consistent with flux transport triggered in the subsolar and dusk sectors due to magnetodisc reconnection.

Exciton interference revealed by energy dependent exciton transfer rate for ring-structured molecular systems.

PubMed

Yan, Yun-An

2016-01-14

The quantum interference is an intrinsic phenomenon in quantum physics for photon and massive quantum particles. In principle, the quantum interference may also occur with quasi-particles, such as the exciton. In this study, we show how the exciton quantum interference can be significant in aggregates through theoretical simulations with hierarchical equations of motion. The systems under investigation are generalized donor-bridge-acceptor model aggregates with the donor consisting of six homogeneous sites assuming the nearest neighbor coupling. For the models with single-path bridge, the exciton transfer time only shows a weak excitation energy dependence. But models with double-path bridge have a new short transfer time scale and the excitation energy dependence of the exciton transfer time assumes clear peak structure which is detectable with today's nonlinear spectroscopy. This abnormality is attributed to the exciton quantum interference and the condition for a clear observation in experiment is also explored.

Working disability in Norwegian patients with vestibular schwannoma: vertigo predicts future dependence.

PubMed

Breivik, Cathrine Nansdal; Nilsen, Roy Miodini; Myrseth, Erling; Finnkirk, Monica Katrine; Lund-Johansen, Morten

2013-12-01

We examined whether reduced hearing, tinnitus, dizziness, and unsteadiness affected the patients' ability to maintain work within a time frame of 2-10 years after diagnosis. A total of 434 consecutive patients were followed at regular intervals. Data on symptoms were scored prospectively and dichotomized by visual analog scales for tinnitus and vertigo. Study design is retrospective. Hearing acuity was scored according to the Gardner-Robertson scale, and unsteadiness was measured on a balance platform. Patients were asked about working status, and scored as receiving governmental compensation for disability. Two hundred six patients were eligible for study. Of these, one died and nine were lost to follow-up. Ninety-seven patients received conservative management, 49 patients recieved gamma knife radiosurgery, and 50 patients were treated by microsurgery. Mean follow-up time was 58.7 months (range, 20-132 months). There was a significant increase in the number of individuals receiving compensation during the study period (P < 0.0001). At baseline, the proportion of pension receivers was within same range as that of the age- and sex-matched Norwegian population (5.61% vs. 6.91%; case-control odds ratio, 0.82; 95% confidence interval 0.45-1.49; P = 0.51, not significant). At the final time point, the increase in the number of receivers deviated significantly from the reference population (case-control odds ratio, 3.80; 95% confidence interval 2.71-5.33; P ≤ 0.001). Examining symptoms at first presentation as predictors of future dependence revealed that vertigo and higher mean age were associated with a higher risk (P < 0.001 and P = 0.015, respectively). No other symptoms were predictive of dependence. In a prospectively followed cohort of Norwegian patients with vestibular schwannoma, vestibular complaints were significant predictors for becoming dependant of disability pension. Copyright © 2013 Elsevier Inc. All rights reserved.

Transient deformation from daily GPS displacement time series: postseismic deformation, ETS and evolving strain rates

NASA Astrophysics Data System (ADS)

Bock, Y.; Fang, P.; Moore, A. W.; Kedar, S.; Liu, Z.; Owen, S. E.; Glasscoe, M. T.

2016-12-01

Detection of time-dependent crustal deformation relies on the availability of accurate surface displacements, proper time series analysis to correct for secular motion, coseismic and non-tectonic instrument offsets, periodic signatures at different frequencies, and a realistic estimate of uncertainties for the parameters of interest. As part of the NASA Solid Earth Science ESDR System (SESES) project, daily displacement time series are estimated for about 2500 stations, focused on tectonic plate boundaries and having a global distribution for accessing the terrestrial reference frame. The "combined" time series are optimally estimated from independent JPL GIPSY and SIO GAMIT solutions, using a consistent set of input epoch-date coordinates and metadata. The longest time series began in 1992; more than 30% of the stations have experienced one or more of 35 major earthquakes with significant postseismic deformation. Here we present three examples of time-dependent deformation that have been detected in the SESES displacement time series. (1) Postseismic deformation is a fundamental time-dependent signal that indicates a viscoelastic response of the crust/mantle lithosphere, afterslip, or poroelastic effects at different spatial and temporal scales. It is critical to identify and estimate the extent of postseismic deformation in both space and time not only for insight into the crustal deformation and earthquake cycles and their underlying physical processes, but also to reveal other time-dependent signals. We report on our database of characterized postseismic motions using a principal component analysis to isolate different postseismic processes. (2) Starting with the SESES combined time series and applying a time-dependent Kalman filter, we examine episodic tremor and slow slip (ETS) in the Cascadia subduction zone. We report on subtle slip details, allowing investigation of the spatiotemporal relationship between slow slip transients and tremor and their underlying physical mechanisms. (3) We present evolving strain dilatation and shear rates based on the SESES velocities for regional subnetworks as a metric for assigning earthquake probabilities and detection of possible time-dependent deformation related to underlying physical processes.

Effect of advanced glycosylation end products (AGEs) on proliferation of human bone marrow mesenchymal stem cells (MSCs) in vitro.

PubMed

Lu, Yi-Qun; Lu, Yan; Li, Hui-Juan; Cheng, Xing-Bo

2012-10-01

This study aims to explore the effect of advanced glycosylation end products (AGEs) on proliferation of human bone marrow mesenchymal stem cells in vitro and the underlying mechanism. Bone marrow cell proliferation was determined by WST-8 assay using Cell Counting Kit-8 under the intervention of AGEs. In addition, the content of maldondialdehyde (MDA) and the activity of superoxide dismutase (SOD) were also measured. The proliferation activity of mesenchymal stem cells (MSCs) was significantly inhibited when AGEs were added to culture medium, and this effect was dose-dependent and time-dependent. As the concentration of AGEs-bovine serum albumin increased, the content of intracellular MDA was significantly increased, but the activity of SOD in cell homogenates was significantly suppressed, which also showed a dose-dependent manner. AGEs could significantly inhibit the proliferation of MSCs in vitro by improving the oxidative stress in MSCs and breaking the homeostasis of intracellular environment.

Effect of Hydrodynamic Interactions on Self-Diffusion of Quasi-Two-Dimensional Colloidal Hard Spheres.

PubMed

Thorneywork, Alice L; Rozas, Roberto E; Dullens, Roel P A; Horbach, Jürgen

2015-12-31

We compare experimental results from a quasi-two-dimensional colloidal hard sphere fluid to a Monte Carlo simulation of hard disks with small particle displacements. The experimental short-time self-diffusion coefficient D(S) scaled by the diffusion coefficient at infinite dilution, D(0), strongly depends on the area fraction, pointing to significant hydrodynamic interactions at short times in the experiment, which are absent in the simulation. In contrast, the area fraction dependence of the experimental long-time self-diffusion coefficient D(L)/D(0) is in quantitative agreement with D(L)/D(0) obtained from the simulation. This indicates that the reduction in the particle mobility at short times due to hydrodynamic interactions does not lead to a proportional reduction in the long-time self-diffusion coefficient. Furthermore, the quantitative agreement between experiment and simulation at long times indicates that hydrodynamic interactions effectively do not affect the dependence of D(L)/D(0) on the area fraction. In light of this, we discuss the link between structure and long-time self-diffusion in terms of a configurational excess entropy and do not find a simple exponential relation between these quantities for all fluid area fractions.

Endorsement of DSM-IV dependence criteria among caffeine users.

PubMed

Hughes, J R; Oliveto, A H; Liguori, A; Carpenter, J; Howard, T

1998-10-01

The purpose of this article is to determine whether some caffeine users endorse clinical indicators of dependence and abuse. We asked 162 randomly-selected caffeine users generic DSM-IV criteria for dependence, abuse, intoxication and withdrawal pertaining to their caffeine use in the last year via a structured telephone interview. The prevalence of endorsement of dependence items was 56% for strong desire or unsuccessful attempt to stop use, 50% for spending a great deal of time with the drug, 28% for using more than intended, 18% for withdrawal, 14% for using despite knowledge of harm, 8% for tolerance and 1% for foregoing activities to use. Seven percent of users met DSM-IV criteria for caffeine intoxication and, among those who had tried to stop caffeine permanently, 24% met DSM-IV research criteria for caffeine withdrawal. Test-retest interviews for dependency agreed in 29/30 cases (97%). Eight expert substance abuse clinicians agreed with self-endorsed caffeine dependence 91% of the time. Our results replicate earlier work and suggest that a substantial proportion of caffeine users exhibit dependence-like behaviors. Further studies are needed to determine whether such users exhibit a clinically significant syndrome of drug dependence.

Development of a questionnaire for assessing dependence on electronic cigarettes among a large sample of ex-smoking E-cigarette users.

PubMed

Foulds, Jonathan; Veldheer, Susan; Yingst, Jessica; Hrabovsky, Shari; Wilson, Stephen J; Nichols, Travis T; Eissenberg, Thomas

2015-02-01

Electronic cigarettes (e-cigs) are becoming increasingly popular, but little is known about their dependence potential. This study aimed to assess ratings of dependence on electronic cigarettes and retrospectively compare them with rated dependence on tobacco cigarettes among a large sample of ex-smokers who switched to e-cigs. A total of 3,609 current users of e-cigs who were ex-cigarette smokers completed a 158-item online survey about their e-cig use, including 10 items designed to assess their previous dependence on cigarettes and 10 almost identical items, worded to assess their current dependence on e-cigs (range 0-20). Scores on the 10-item Penn State (PS) Cigarette Dependence Index were significantly higher than on the comparable PS Electronic Cigarette Dependence Index (14.5 vs. 8.1, p < .0001). In multivariate analysis, those who had used e-cigs longer had higher e-cig dependence scores, as did those using more advanced e-cigs that were larger than a cigarette and had a manual button. Those using zero nicotine liquid had significantly lower e-cig dependence scores than those using 1-12 mg/ml, who scored significantly lower than those using 13 or greater mg/ml nicotine liquid (p < .003). Current e-cigarette users reported being less dependent on e-cigarettes than they retrospectively reported having been dependent on cigarettes prior to switching. E-cig dependence appears to vary by product characteristics and liquid nicotine concentration, and it may increase over time. © The Author 2014. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Time-dependent postural control adaptations following a neuromuscular warm-up in female handball players: a randomized controlled trial.

PubMed

Steib, Simon; Zahn, Peter; Zu Eulenburg, Christine; Pfeifer, Klaus; Zech, Astrid

2016-01-01

Female handball athletes are at a particular risk of sustaining lower extremity injuries. The study examines time-dependent adaptations of static and dynamic balance as potential injury risk factors to a specific warm-up program focusing on neuromuscular control. Fourty one (24.0 ± 5.9 years) female handball athletes were randomized to an intervention or control group. The intervention group implemented a 15-min specific neuromuscular warm-up program, three times per week for eleven weeks, whereas the control group continued with their regular warm-up. Balance was assessed at five time points. Measures included the star excursion balance test (SEBT), and center of pressure (COP) sway velocity during single-leg standing. No baseline differences existed between groups in demographic data. Adherence to neuromuscular warm-up was 88.7 %. Mean COP sway velocity decreased significantly over time in the intervention group (-14.4 %; p  < .001), but not in the control group (-6.2 %; p  = 0.056). However, these effects did not differ significantly between groups ( p  = .098). Mean changes over time in the SEBT score were significantly greater ( p  = .014) in the intervention group (+5.48) compared to the control group (+3.45). Paired t-tests revealed that the first significant balance improvements were observed after 6 weeks of training. A neuromuscular warm-up positively influences balance variables associated with an increased risk of lower extremity injuries in female handball athletes. The course of adaptations suggests that a training volume of 15 min, three times weekly over at least six weeks produces measurable changes. Retrospectively registered on 4th October 2016. Registry: clinicaltrials.gov. Trial number: NCT02925377.

The Estimation of Short Time Intervals as a Function of Age and Metronome Pacing.

ERIC Educational Resources Information Center

Kline, Donald W.; And Others

1980-01-01

The time judgments of the older participants were significantly and systematically determined by a metronome rate. Results are consistent with the notion of increased field-dependence among older persons and suggest that their greater social conformity and their inability to ignore irrelevant stimuli might also be explicable. (Author)

Employers' Support for Adult Higher Education Students in Liberal Post-Socialist Contexts

ERIC Educational Resources Information Center

Saar, Ellu; Vöörmann, Rein; Lang, Ailen

2014-01-01

In most European countries, the proportion of adult students among both full-time and part-time workers has increased significantly over recent decades. Undertaking paid work is also increasingly common among traditional students. The opportunities to work while studying depend largely on the role of employers in promoting learning. However, both…

Analysis of Electrokinetic Mixing Using AC Electric Field and Patchwise Surface Heterogeneities

NASA Astrophysics Data System (ADS)

Luo, Win-Jet; Yarn, Kao-Feng; Hsu, Shou-Ping

2007-04-01

In this paper, the authors investigate the use of an applied AC electric field and microchannel surface heterogeneities to carry out the microfluidic mixing of two-dimensional, time-dependent electroosmotic flows. The time-dependent flow fields within the microchannel are simulated using the backwards-Euler time-stepping numerical method. The mixing efficiencies obtained in microchannels with two different patchwise surface heterogeneity patterns are investigated. In general, the results show that the application of an AC electric field significantly reduces the required mixing length compared with the use of a DC electric field. Furthermore, the presence of oppositely charged surface heterogeneities on the microchannel walls results in the formation of localized flow circulation regions within the bulk flow. These circulation regions grow and decay periodically in accordance with the periodic variation of the AC electric field intensity and provide an effective means of enhancing species mixing in the microchannel. Consequently, the use of an AC electric field together with patchwise surface heterogeneities permits a significant reduction in both the mixing channel length and the retention time required to attain a homogeneous solution.

Viscoelastic modeling of deformation and gravity changes induced by pressurized magmatic sources

NASA Astrophysics Data System (ADS)

Currenti, Gilda

2018-05-01

Gravity and height changes, which reflect magma accumulation in subsurface chambers, are evaluated using analytical and numerical models in order to investigate their relationships and temporal evolutions. The analysis focuses mainly on the exploration of the time-dependent response of gravity and height changes to the pressurization of ellipsoidal magmatic chambers in viscoelastic media. Firstly, the validation of the numerical Finite Element results is performed by comparison with analytical solutions, which are devised for a simple spherical source embedded in a homogeneous viscoelastic half-space medium. Then, the effect of several model parameters on time-dependent height and gravity changes is investigated thanks to the flexibility of the numerical method in handling complex configurations. Both homogeneous and viscoelastic shell models reveal significantly different amplitudes in the ratio between gravity and height changes depending on geometry factors and medium rheology. The results show that these factors also influence the relaxation characteristic times of the investigated geophysical changes. Overall, these temporal patterns are compatible with time-dependent height and gravity changes observed on Etna volcano during the 1994-1997 inflation period. By modeling the viscoelastic response of a pressurized prolate magmatic source, a general agreement between computed and observed geophysical variations is achieved.

Three-dimensional collagenous niche and azacytidine selectively promote time-dependent cardiomyogenesis from human bone marrow-derived MSC spheroids.

PubMed

Joshi, Jyotsna; Mahajan, Gautam; Kothapalli, Chandrasekhar R

2018-04-17

Endogenous adult cardiac regenerative machinery is not capable of replacing the lost cells following myocardial infarction, often leading to permanent alterations in structure-function-mechanical properties. Regenerative therapies based on delivering autologous stem cells within an appropriate 3D milieu could meet such demand, by enabling homing and directed differentiation of the transplanted cells into lost specialized cell populations. Since type I collagen is the predominant cardiac tissue matrix protein, we here optimized the 3D niche which could promote time-dependent evolution of cardiomyogenesis from human bone marrow-derived mesenchymal stem cells (BM-MSC). 3D collagen gel physical and mechanical characteristics were assessed using SEM and AFM, respectively, while the standalone and combined effects of collagen concentration, culture duration, and 5-azacytidine (aza) dose on the phenotype and genotype of MSC spheroids were quantified using immunofluorescence labeling and RT-PCR analysis. Increasing collagen concentration led to a significant increase in Young's modulus (p < 0.01) but simultaneous decrease in the mean pore size, resulting in stiffer gels. Spheroid formation significantly modulated MSC differentiation and genotype, mostly due to better cell-cell interactions. Among the aza dosages tested, 10 μM appears to be optimal, while 3 mg/ml gels resulted in significantly lower cell viability compared to 1 or 2 mg/ml gels. Stiffer gels (2 and 3 mg/ml) and exposure to 10 μM aza upregulated early and late cardiac marker expressions in a time-dependent fashion. On the other hand, cell-cell signaling within the MSC spheroids seem to have a strong role in influencing mature cardiac markers expression, since neither aza nor gel stiffness seem to significantly improve their expression. Western blot analysis suggested that canonical Wnt/β-catenin signaling pathway might be primarily mediating the observed benefits of aza on cardiac differentiation of MSC spheroids. In conclusion, 2 mg/ml collagen and 10 μM aza appears to offer optimal 3D microenvironment in terms of cell viability and time-dependent evolution of cardiomyogenesis from human BM-MSCs, with significant applications in cardiac tissue engineering and stem cell transplantation for regenerating lost cardiac tissue. © 2018 Wiley Periodicals, Inc.

Predicting the dynamics of bacterial growth inhibition by ribosome-targeting antibiotics

NASA Astrophysics Data System (ADS)

Greulich, Philip; Doležal, Jakub; Scott, Matthew; Evans, Martin R.; Allen, Rosalind J.

2017-12-01

Understanding how antibiotics inhibit bacteria can help to reduce antibiotic use and hence avoid antimicrobial resistance—yet few theoretical models exist for bacterial growth inhibition by a clinically relevant antibiotic treatment regimen. In particular, in the clinic, antibiotic treatment is time-dependent. Here, we use a theoretical model, previously applied to steady-state bacterial growth, to predict the dynamical response of a bacterial cell to a time-dependent dose of ribosome-targeting antibiotic. Our results depend strongly on whether the antibiotic shows reversible transport and/or low-affinity ribosome binding (‘low-affinity antibiotic’) or, in contrast, irreversible transport and/or high affinity ribosome binding (‘high-affinity antibiotic’). For low-affinity antibiotics, our model predicts that growth inhibition depends on the duration of the antibiotic pulse, and can show a transient period of very fast growth following removal of the antibiotic. For high-affinity antibiotics, growth inhibition depends on peak dosage rather than dose duration, and the model predicts a pronounced post-antibiotic effect, due to hysteresis, in which growth can be suppressed for long times after the antibiotic dose has ended. These predictions are experimentally testable and may be of clinical significance.

Predicting the dynamics of bacterial growth inhibition by ribosome-targeting antibiotics

PubMed Central

Greulich, Philip; Doležal, Jakub; Scott, Matthew; Evans, Martin R; Allen, Rosalind J

2017-01-01

Understanding how antibiotics inhibit bacteria can help to reduce antibiotic use and hence avoid antimicrobial resistance—yet few theoretical models exist for bacterial growth inhibition by a clinically relevant antibiotic treatment regimen. In particular, in the clinic, antibiotic treatment is time-dependent. Here, we use a theoretical model, previously applied to steady-state bacterial growth, to predict the dynamical response of a bacterial cell to a time-dependent dose of ribosome-targeting antibiotic. Our results depend strongly on whether the antibiotic shows reversible transport and/or low-affinity ribosome binding (‘low-affinity antibiotic’) or, in contrast, irreversible transport and/or high affinity ribosome binding (‘high-affinity antibiotic’). For low-affinity antibiotics, our model predicts that growth inhibition depends on the duration of the antibiotic pulse, and can show a transient period of very fast growth following removal of the antibiotic. For high-affinity antibiotics, growth inhibition depends on peak dosage rather than dose duration, and the model predicts a pronounced post-antibiotic effect, due to hysteresis, in which growth can be suppressed for long times after the antibiotic dose has ended. These predictions are experimentally testable and may be of clinical significance. PMID:28714461

Neuron-derived orphan receptor 1 promoted human pulmonary artery smooth muscle cells proliferation.

PubMed

Wang, Chang-Guo; Lei, Wei; Li, Chang; Zeng, Da-Xiong; Huang, Jian-An

2015-05-01

As a transcription factor of the nuclear receptor superfamily, neuron-derived orphan receptor 1 (NOR1) is induced rapidly in response to various extracellular stimuli. But, it is still unclear its role in pulmonary artery smooth muscle cells proliferation. Human PASMCs were cultured in vitro and stimulated by serum. The special antisense oligodeoxynucleotides (AS-ODNs) were used to knockdown human NOR1 gene expression. Real-time PCR and Western-blot were used to evaluate the gene expression and protein levels. Fetal bovine serum (FBS) induced human PASMCs proliferation in a dose dependent manner. Furthermore, FBS promoted NOR1 gene expression in a dose dependent manner and a time dependent manner. 10% FBS induced a maximal NOR1 mRNA levels at 2 h. FBS also induced a significant higher NOR1 protein levels as compared with control. The NOR1 over-expressed plasmid significantly promoted DNA synthesis and cells proliferation. Moreover, the special AS-ODNs against human NOR1 not only prevented NOR1 expression but also inhibited DNA synthesis and cells proliferation significantly. The NOR1 over-expression plasmid could up-regulate cyclin D1 expression markedly, but the AS-ODNs inhibited cyclin D1 expression significantly. So, we concluded that NOR1 could promote human PASMCs proliferation. Cyclin D1 might be involved in this process.

Dynamics of vapor bubbles growth at boiling resulting from enthalpy excess of the surrounding superheated liquid and sound pulses generated by bubbles

NASA Astrophysics Data System (ADS)

Dorofeev, B. M.; Volkova, V. I.

2016-01-01

The results of experiments investigating the exponential dependence of the vapor bubble radius on time at saturated boiling are generalized. Three different methods to obtain this dependence are suggested: (1) by the application of the transient heat conduction equation, (2) by using the correlations of energy conservation, and (3) by solving a similar electrodynamic problem. Based on the known experimental data, the accuracy of the dependence up to one percent and a few percent accuracy of its description based on the sound pressure generated by a vapor bubble have been determined. A significant divergence of the power dependence of the vapor bubble radius on time (with an exponent of 1/2) with the experimental results and its inadequacy for the description of the sound pulse generated by the bubble have been demonstrated.

Grouped comparisons of sleep quality for new and personal bedding systems.

PubMed

Jacobson, Bert H; Wallace, Tia J; Smith, Doug B; Kolb, Tanner

2008-03-01

The purpose of this study was to compare sleep comfort and quality between personal and new bedding systems. A convenience sample (women, n=33; men, n=29) with no clinical history of disturbed sleep participated in the study. Subjects recorded back and shoulder pain, sleep quality, comfort, and efficiency for 28 days each in their personal beds (pre) and in new medium-firm bedding systems (post). Repeated measures ANOVAs revealed significant improvement between pre- and post-test means for all dependent variables. Furthermore, reduction of pain and stiffness and improvement of sleep comfort and quality became more prominent over time. No significant differences were found for the groupings of age, weight, height, or body mass index. It was found that for the cheapest category of beds, lower back pain was significantly (p<0.01) more prominent than for the medium and higher priced beds. Average bed age was 9.5yrs. It was concluded that new bedding systems can significantly improve selected sleep variables and that continuous sleep quality may be dependent on timely replacement of bedding systems.

The influence of LED lighting on task accuracy: time of day, gender and myopia effects

NASA Astrophysics Data System (ADS)

Rao, Feng; Chan, A. H. S.; Zhu, Xi-Fang

2017-07-01

In this research, task errors were obtained during performance of a marker location task in which the markers were shown on a computer screen under nine LED lighting conditions; three illuminances (100, 300 and 500 lx) and three color temperatures (3000, 4500 and 6500 K). A total of 47 students participated voluntarily in these tasks. The results showed that task errors in the morning were small and nearly constant across the nine lighting conditions. However in the afternoon, the task errors were significantly larger and varied across lighting conditions. The largest errors for the afternoon session occurred when the color temperature was 4500 K and illuminance 500 lx. There were significant differences between task errors in the morning and afternoon sessions. No significant difference between females and males was found. Task errors for high myopia students were significantly larger than for the low myopia students under the same lighting conditions. In summary, the influence of LED lighting on task accuracy during office hours was not gender dependent, but was time of day and myopia dependent.

Modeling impurity production and transport during ELM transients in a DIII-D lower single null configuration.

NASA Astrophysics Data System (ADS)

Hogan, J.; Fenstermacher, M.; Groth, M.; West, P.; Coster, D.; Thomas, P.

2003-10-01

Better understanding of carbon production and eventual pathways is an important need for ITER. ELM events can provide a significant carbon source, and small scale experiments predict significant dependence of C production rates on incident deuterium flux and surface temperature, quantities which change significantly during an ELM event. Thus, development of better quantitative models has been hampered by lack of sufficient time resolution during ELMs. Recent progress on DIII-D has significantly improved the spectroscopic resolution [1, 2]. Measured CIII evolution during low- and high-density DIII-D LSN ELMy H-modes (type I and type I-III, respectively) has been compared with modeling using the solps5.0/Eirene99 coupled edge code, and the CASTEM- 2000 3-D, time dependent thermal analysis code. The latter provides time-resolved absolute surface temperature distributions for the cases described in [2]. Comparison with observations using the Roth et al annealing model for chemical sputtering finds qualitative agreement. However, the transition in ELM type/frequency as density increases is the most important factor, and this is an input to the calculation given the present state of first principles ELM models. [1] M Fenstermacher et al EPS2003 [2] M Groth et al J Nucl Mater 2003

Density-Dependent Conformable Space-time Fractional Diffusion-Reaction Equation and Its Exact Solutions

NASA Astrophysics Data System (ADS)

Hosseini, Kamyar; Mayeli, Peyman; Bekir, Ahmet; Guner, Ozkan

2018-01-01

In this article, a special type of fractional differential equations (FDEs) named the density-dependent conformable fractional diffusion-reaction (DDCFDR) equation is studied. Aforementioned equation has a significant role in the modelling of some phenomena arising in the applied science. The well-organized methods, including the \\exp (-φ (\\varepsilon )) -expansion and modified Kudryashov methods are exerted to generate the exact solutions of this equation such that some of the solutions are new and have been reported for the first time. Results illustrate that both methods have a great performance in handling the DDCFDR equation.

Time-dependent gas-liquid interaction in molecular-sized nanopores.

PubMed

Sun, Yueting; Li, Penghui; Qiao, Yu; Li, Yibing

2014-10-08

Different from a bulk phase, a gas nanophase can have a significant effect on liquid motion. Herein we report a series of experimental results on molecular behaviors of water in a zeolite β of molecular-sized nanopores. If sufficient time is provided, the confined water molecules can be "locked" inside a nanopore; otherwise, gas nanophase provides a driving force for water "outflow". This is due to the difficult molecular site exchanges and the relatively slow gas-liquid diffusion in the nanoenvironment. Depending on the loading rate, the zeolite β/water system may exhibit either liquid-spring or energy-absorber characteristics.

Double ionization of neon in elliptically polarized femtosecond laser fields

NASA Astrophysics Data System (ADS)

Kang, HuiPeng; Henrichs, Kevin; Wang, YanLan; Hao, XiaoLei; Eckart, Sebastian; Kunitski, Maksim; Schöffler, Markus; Jahnke, Till; Liu, XiaoJun; Dörner, Reinhard

2018-06-01

We present a joint experimental and theoretical investigation of the correlated electron momentum spectra from strong-field double ionization of neon induced by elliptically polarized laser pulses. A significant asymmetry of the electron momentum distributions along the major polarization axis is reported. This asymmetry depends sensitively on the laser ellipticity. Using a three-dimensional semiclassical model, we attribute this asymmetry pattern to the ellipticity-dependent probability distributions of recollision time. Our work demonstrates that, by simply varying the ellipticity, the correlated electron emission can be two-dimensionally controlled and the recolliding electron trajectories can be steered on a subcycle time scale.

X-ray variability of Pleiades late-type stars as observed with the ROSAT-PSPC

NASA Astrophysics Data System (ADS)

Marino, A.; Micela, G.; Peres, G.; Sciortino, S.

2003-08-01

We present a comprehensive analysis of X-ray variability of the late-type (dF7-dM) Pleiades stars, detected in all ROSAT-PSPC observations; X-ray variations on short (hours) and medium (months) time scales have been explored. We have grouped the stars in two samples: 89 observations of 42 distinct dF7-dK2 stars and 108 observations of 61 dK3-dM stars. The Kolmogorov-Smirnov test applied on all X-ray photon time series show that the percentage of cases of significant variability is quite similar on both samples, suggesting that the presence of variability does not depend on mass for the time scales and mass range explored. The comparison between the Time X-ray Amplitude Distribution functions (XAD) of the set of dF7-dK2 and of the dK3-dM show that, on short time scales, dK3-dM stars show larger variations than dF7-dK2. A subsample of eleven dF7-dK2 and eleven dK3-dM Pleiades stars allows the study of variability on longer time scales: we found that variability on medium - long time scales is relatively more common among dF7-dK2 stars than among dK3-dM ones. For both dF7-dK2 Pleiades stars and dF7-dK2 field stars, the variability on short time scales depends on Lx while this dependence has not been observed among dK3-dM stars. It may be that the variability among dK3-dM stars is dominated by flares that have a similar luminosity distribution for stars of different Lx, while flaring distribution in dF7-dK2 stars may depend on X-ray luminosity. The lowest mass stars show significant rapid variability (flares?) and no evidence of rotation modulation or cycles. On the contrary, dF7-dK2 Pleiades stars show both rapid variability and variations on longer time scales, likely associated with rotational modulation or cycles.

The effect of presentation rate on implicit sequence learning in aging.

PubMed

Foster, Chris M; Giovanello, Kelly S

2017-02-01

Implicit sequence learning is thought to be preserved in aging when the to-be learned associations are first-order; however, when associations are second-order, older adults (OAs) tend to experience deficits as compared to young adults (YAs). Two experiments were conducted using a first (Experiment 1) and second-order (Experiment 2) serial-reaction time task. Stimuli were presented at a constant rate of either 800 milliseconds (fast) or 1200 milliseconds (slow). Results indicate that both age groups learned first-order dependencies equally in both conditions. OAs and YAs also learned second-order dependencies, but the learning of lag-2 information was significantly impacted by the rate of presentation for both groups. OAs showed significant lag-2 learning in slow condition while YAs showed significant lag-2 learning in the fast condition. The sensitivity of implicit sequence learning to the rate of presentation supports the idea that OAs and YAs different processing speeds impact the ability to build complex associations across time and intervening events.

Changes in Nutrition-Related Behaviors in Alcohol-Dependent Patients After Outpatient Detoxification: The Role of Chocolate.

PubMed

Stickel, Anna; Rohdemann, Maren; Landes, Tom; Engel, Katharina; Banas, Roman; Heinz, Andreas; Müller, Christian A

2016-01-01

Previous studies have reported changes in nutrition-related behaviors in alcohol-dependent patients after alcohol detoxification, but prospective studies assessing the effects of these changes on maintaining abstinence are lacking. To assess changes in craving and consumption of chocolate and other sweets over time up to six months after outpatient alcohol detoxification treatment and to detect differences in abstinent versus nonabstinent patients. One hundred and fifty alcohol-dependent patients were included in this prospective observational study. Participants completed self-report questionnaires on nutrition-related behaviors and craving before detoxification treatment (baseline, t1), one week (t2), one month (t3), and six months later (t4). Significant changes in craving for and consumption of chocolate as well as in craving for other sweets were observed over time. Increases were most prominent within the first month. Patients who remained abstinent until t3 consumed three times more chocolate than nonabstainers. One quarter of the patients switched from being rare (t1) to frequent (t3) chocolate eaters, and 84% of these remained abstinent until t3. No significant correlations were found between craving for alcohol and craving for or consumption of chocolate or other sweets. In the first month after outpatient alcohol detoxification treatment, significant changes in nutrition-related behaviors were observed. These changes were not associated with alcohol craving. For a subgroup, increasing the frequency of chocolate consumption might be a temporary protective factor with respect to alcohol relapse.

Minority games with score-dependent and agent-dependent payoffs

NASA Astrophysics Data System (ADS)

Ren, F.; Zheng, B.; Qiu, T.; Trimper, S.

2006-10-01

Score-dependent and agent-dependent payoffs of the strategies are introduced into the standard minority game. The intrinsic periodicity is consequently removed, and the stylized facts arise, such as long-range volatility correlations and “fat tails” in the distribution of the returns. The agent dependence of the payoffs is essential in producing the long-range volatility correlations. The new payoffs lead to a better performance in the dynamic behavior nonlocal in time, and can coexist with the inactive strategy. We also observe that the standard deviation σ2/N is significantly reduced, thus the efficiency of the system is distinctly improved. Based on this observation, we give a qualitative explanation for the long-range volatility correlations.

Evaluation of CNS activities of aerial parts of Cynodon dactylon Pers. in mice.

PubMed

Pal, Dilipkumar

2008-01-01

The dried extracts of aerial parts of Cynodon dactylon Pers. (Graminae) were evaluated for CNS activities in mice. The ethanol extract of aerial parts of C. dactylon (EECD) was found to cause significant depression in general behavioral profiles in mice. EECD significantly potentiated the sleeping time in mice induced by standard hypnotics viz. pentobarbitone sodium, diazepam, and meprobamate in a dose dependant manner. EECD showed significant analgesic properties as evidenced by the significant reduction in the number of writhes and stretches induced in mice by 1.2% acetic acid solution. It also potentiated analgesia induced by morphine and pethidine in mice. EECD inhibited the onset and the incidence of convulsion in a dose dependent manner against pentylenetetrazole (PTZ)-induced convulsion. The present study indicates that EECD has significant CNS depressant activities.

Adaptation of mastication mechanics and eating behaviour to small differences in food texture.

PubMed

Le Révérend, Benjamin; Saucy, Françoise; Moser, Mireille; Loret, Chrystel

2016-10-15

Eating behaviour is significantly modified with the consumption of soft or hard textures. However, it is of interest to describe how adaptive is mastication to a narrow range of texture. ElectroMyoGraphy (EMG) and Kinematics of Jaw Movements (KJM) techniques were used simultaneously to follow mastication muscle activity and jaw motion during mastication of seven cereal products. We show that parameters such as the time of chewing activity, the number of chewing cycles, the chewing muscle EMG activity and the volume occupied for each chewing cycle are amongst others significantly different depending on products tested, even though the textural product space investigated is quite narrow (cereal finger foods). In addition, through a time/chewing cycle dependent analysis of the chewing patterns, we demonstrate that different foods follow different breakdown pathways during oral processing, depending on their initial structural properties, as dictated by their formulation and manufacturing process. In particular, we show that mastication behaviour of cereal foods can be partly classified based on the process that is used to generate product internal structure (e.g. baking vs extrusion). To the best of our knowledge, such time dependent analyses have not yet been reported. Those results suggest that it is possible to influence the chewing behaviour by modifying food textures within the same "food family". This opens new possibilities to design foods for specific populations that cannot accomplish specific oral processing tasks. Copyright © 2016. Published by Elsevier Inc.

Circadian time-dependent chemopreventive potential of withaferin-A in 7,12-dimethylbenz[a]anthracene-induced oral carcinogenesis.

PubMed

Manoharan, Shanmugam; Panjamurthy, Kuppusamy; Balakrishnan, Subramanian; Vasudevan, Kalaiarasan; Vellaichamy, Lakshmanan

2009-01-01

Circadian time-dependent treatment with chemotherapeutic drugs (chronotherapy) optimizes the therapeutic index by maximizing treatment efficacy and minimizing toxicity. The circadian time-dependent chemopreventive and anti-lipid peroxidative efficacy of withaferin-A in 7,12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch carcinogenesis was investigated in the present study. We induced oral squamous cell carcinoma in the buccal pouches of golden Syrian hamsters during the day (4:00, 8:00, 12:00, 16:00, 20:00 and 24:00) by application of DMBA three times per week for 14 weeks. The circadian time-dependent tumor incidence, volume and burden were observed in hamsters treated with either DMBA alone or DMBA + withaferin-A. The circadian pattern of lipid peroxidation by-products, as measured by the formation of thiobarbituric acid reactive substances (TBARS) and enzymatic antioxidants [superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx)], was also analyzed in the buccal mucosa of DMBA-treated hamsters. We found the highest incidence of tumor formation at 24.00 h in hamsters treated with DMBA alone as compared to other experimental groups. Circadian dysregulation of lipid peroxidation and antioxidant status was observed in DMBA-treated animals as compared to control animals. Oral (po) administration of withaferin-A (20 mg/kg) completely prevented the formation of tumors between 8.00 h and 12.00 h and synchronized the status of lipid peroxidation and antioxidants in the buccal mucosa of hamsters treated with DMBA alone. Also, oral administration of withaferin-A to DMBA-treated animals significantly reduced the formation of tumors and synchronized the status of lipid peroxidation and antioxidants in the rest of the time intervals. Our study thus suggests that withaferin-A has significant chemopreventive and anti-lipid peroxidative potential in DMBA-induced oral carcinogenesis, probably by interfering with DMBA-induced abnormal cell proliferation in the buccal mucosa.

Power law time dependence of river flood decay and its relationship to long term discharge frequency distribution. [California

NASA Technical Reports Server (NTRS)

Schubert, G.; Lingenfelter, R. E.

1973-01-01

Investigations have continued into the possibility that significant information on stream flow rates can be obtained from aerial and satellite imagery of river meander patterns by seeking a correlation between the meander and discharge spectra of rivers. Such a correlation could provide the basis for a simple and inexpensive technique for remote sensing of the water resources of large geographical areas, eliminating the need for much hydrologic recording. The investigation of the nature of the meander and discharge spectra and their interrelationship can also contribute to a more fundamental understanding of the processes of both river meander formation and drainage of large basins. It has been found that floods decay with an inverse power law dependence on time. The exponent of this dependence varies from river to river and even from station to station along the same river. This power law time dependence makes possible the forecasting of river discharge with an uncertainty of about 5% for as long as a month following the flood peak.

Timescale- and Sensory Modality-Dependency of the Central Tendency of Time Perception.

PubMed

Murai, Yuki; Yotsumoto, Yuko

2016-01-01

When individuals are asked to reproduce intervals of stimuli that are intermixedly presented at various times, longer intervals are often underestimated and shorter intervals overestimated. This phenomenon may be attributed to the central tendency of time perception, and suggests that our brain optimally encodes a stimulus interval based on current stimulus input and prior knowledge of the distribution of stimulus intervals. Two distinct systems are thought to be recruited in the perception of sub- and supra-second intervals. Sub-second timing is subject to local sensory processing, whereas supra-second timing depends on more centralized mechanisms. To clarify the factors that influence time perception, the present study investigated how both sensory modality and timescale affect the central tendency. In Experiment 1, participants were asked to reproduce sub- or supra-second intervals, defined by visual or auditory stimuli. In the sub-second range, the magnitude of the central tendency was significantly larger for visual intervals compared to auditory intervals, while visual and auditory intervals exhibited a correlated and comparable central tendency in the supra-second range. In Experiment 2, the ability to discriminate sub-second intervals in the reproduction task was controlled across modalities by using an interval discrimination task. Even when the ability to discriminate intervals was controlled, visual intervals exhibited a larger central tendency than auditory intervals in the sub-second range. In addition, the magnitude of the central tendency for visual and auditory sub-second intervals was significantly correlated. These results suggest that a common modality-independent mechanism is responsible for the supra-second central tendency, and that both the modality-dependent and modality-independent components of the timing system contribute to the central tendency in the sub-second range.

A two-dimensional, time-dependent model of suspended sediment transport and bed reworking for continental shelves

USGS Publications Warehouse

Harris, C.K.; Wiberg, P.L.

2001-01-01

A two-dimensional, time-dependent solution to the transport equation is formulated to account for advection and diffusion of sediment suspended in the bottom boundary layer of continental shelves. This model utilizes a semi-implicit, upwind-differencing scheme to solve the advection-diffusion equation across a two-dimensional transect that is configured so that one dimension is the vertical, and the other is a horizontal dimension usually aligned perpendicular to shelf bathymetry. The model calculates suspended sediment concentration and flux; and requires as input wave properties, current velocities, sediment size distributions, and hydrodynamic sediment properties. From the calculated two-dimensional suspended sediment fluxes, we quantify the redistribution of shelf sediment, bed erosion, and deposition for several sediment sizes during resuspension events. The two-dimensional, time-dependent approach directly accounts for cross-shelf gradients in bed shear stress and sediment properties, as well as transport that occurs before steady-state suspended sediment concentrations have been attained. By including the vertical dimension in the calculations, we avoid depth-averaging suspended sediment concentrations and fluxes, and directly account for differences in transport rates and directions for fine and coarse sediment in the bottom boundary layer. A flux condition is used as the bottom boundary condition for the transport equation in order to capture time-dependence of the suspended sediment field. Model calculations demonstrate the significance of both time-dependent and spatial terms on transport and depositional patterns on continental shelves. ?? 2001 Elsevier Science Ltd. All rights reserved.

Optical characterization of chemistry in shocked nitromethane with time-dependent density functional theory.

PubMed

Pellouchoud, Lenson A; Reed, Evan J

2013-11-27

We compute the optical properties of the liquid-phase energetic material nitromethane (CH3NO2) for the first 100 ps behind the front of a simulated shock at 6.5 km/s, close to the experimentally observed detonation shock speed of the material. We utilize molecular dynamics trajectories computed using the multiscale shock technique (MSST) for time-resolved optical spectrum calculations based on both linear response time-dependent DFT (TDDFT) and the Kubo-Greenwood formula with Kohn-Sham DFT wave functions. We find that the TDDFT method predicts an optical conductivity 25-35% lower than the Kubo-Greenwood calculation and provides better agreement with the experimentally measured index of refraction of unreacted nitromethane. We investigate the influence of electronic temperature on the Kubo-Greenwood spectra and find no significant effect at optical wavelengths. In both Kubo-Greenwood and TDDFT, the spectra evolve nonmonotonically in time as shock-induced chemistry takes place. We attribute the time-resolved absorption at optical wavelengths to time-dependent populations of molecular decomposition products, including NO, CNO, CNOH, H2O, and larger molecules. These calculations offer direction for guiding and interpreting ultrafast optical measurements on reactive materials.

Chiral tunneling modulated by a time-periodic potential on the surface states of a topological insulator

PubMed Central

Li, Yuan; Jalil, Mansoor B. A.; Tan, S. G.; Zhao, W.; Bai, R.; Zhou, G. H.

2014-01-01

Time-periodic perturbation can be used to modify the transport properties of the surface states of topological insulators, specifically their chiral tunneling property. Using the scattering matrix method, we study the tunneling transmission of the surface states of a topological insulator under the influence of a time-dependent potential and finite gate bias voltage. It is found that perfect transmission is obtained for electrons which are injected normally into the time-periodic potential region in the absence of any bias voltage. However, this signature of Klein tunneling is destroyed when a bias voltage is applied, with the transmission probability of normally incident electrons decreasing with increasing gate bias voltage. Likewise, the overall conductance of the system decreases significantly when a gate bias voltage is applied. The characteristic left-handed helicity of the transmitted spin polarization is also broken by the finite gate bias voltage. In addition, the time-dependent potential modifies the large-angle transmission profile, which exhibits an oscillatory or resonance-like behavior. Finally, time-dependent transport modes (with oscillating potential in the THz frequency) can result in enhanced overall conductance, irrespective of the presence or absence of the gate bias voltage. PMID:24713634

Modeling of thermal lensing in a [1 1 1]-cut Nd:YAG rod with temperature-dependent parameters and different pumping profiles

NASA Astrophysics Data System (ADS)

Bričkus, D.; Dement'ev, A. S.

2017-05-01

Temperature dependences of the thermo-optical coefficients of YAG crystals are often neglected when thermal lensing in laser rods is investigated, though their influence is very significant. It is especially significant for transversally non-uniform thermal loading. An analytical solution of the heat transfer equation with only the radial heat flow is found in the integral form, which is very convenient for numerical simulations. Uniform, top-hat, parabolic, Gaussian, super-Gaussian and annular heat source distributions are used in the calculations. The generalization of the thermally-induced refractive index change for long enough [1 1 1]-cut YAG rods to the case of temperature-dependent YAG parameters is developed and applied to the calculation of the corresponding optical path differences. Different definitions of the optical power of the aberrated thermal lens (TL) are discussed in detail. It is shown that for each of the heat source distributions, the temperature dependences of the YAG parameters significantly increase (1.5-1.8 times) the paraxial optical power of the induced TL.

Dependency on Smartphone Use and Its Association with Anxiety in Korea.

PubMed

Lee, Kyung Eun; Kim, Si-Heon; Ha, Tae-Yang; Yoo, Young-Myong; Han, Jai-Jun; Jung, Jae-Hyuk; Jang, Jae-Yeon

2016-01-01

South Korea has the highest rate of smartphone ownership worldwide, which is a potential concern given that smartphone dependency may have deleterious effects on health. We investigated the relationship between smartphone dependency and anxiety. Participants included 1,236 smartphone-using students (725 men and 511 women) from six universities in Suwon, South Korea. Participants completed measures of smartphone use, smartphone dependency, anxiety, and general characteristics (i.e., demographic, health-related, and socioeconomic characteristics). To measure smartphone dependency and anxiety, we used questionnaires of Yang's test developed from Young's Internet Addiction Test and Zung's Self-Rating Anxiety Scale. We used multiple logistic regression to determine the association between smartphone dependency and anxiety after adjusting for relevant factors. On a scale from 25 to 100, with higher scores on the smartphone dependency test indicating greater dependency, women were significantly more dependent on smartphones than were men (mean smartphone dependency score: 50.7 vs. 56.0 for men and women, respectively, p<0.001). However, the amount of time spent using smartphones and the purpose of smartphone use affected smartphone dependency in both men and women. Particularly, when daily use time increased, smartphone dependency showed an increasing trend. Compared with times of use <2 hours vs. ≥6 hours, men scored 46.2 and 56.0 on the smartphone dependency test, while women scored 48.0 and 60.4, respectively (p<0.001). Finally, for both men and women, increases in smartphone dependency were associated with increased anxiety scores. With each one-point increase in smartphone dependency score, the risk of abnormal anxiety in men and women increased by 10.1% and 9.2%, respectively (p<0.001). Among this group of university students in South Korea, smartphone dependency appeared to be associated with increased anxiety. Standards for smartphone use might help prevent deleterious health effects.

Dependency on Smartphone Use and Its Association with Anxiety in Korea

PubMed Central

Lee, Kyung Eun; Kim, Si-Heon; Ha, Tae-Yang; Yoo, Young-Myong; Han, Jai-Jun; Jung, Jae-Hyuk

2016-01-01

Objective South Korea has the highest rate of smartphone ownership worldwide, which is a potential concern given that smartphone dependency may have deleterious effects on health. We investigated the relationship between smartphone dependency and anxiety. Methods Participants included 1,236 smartphone-using students (725 men and 511 women) from six universities in Suwon, South Korea. Participants completed measures of smartphone use, smartphone dependency, anxiety, and general characteristics (i.e., demographic, health-related, and socioeconomic characteristics). To measure smartphone dependency and anxiety, we used questionnaires of Yang's test developed from Young's Internet Addiction Test and Zung's Self-Rating Anxiety Scale. We used multiple logistic regression to determine the association between smartphone dependency and anxiety after adjusting for relevant factors. Results On a scale from 25 to 100, with higher scores on the smartphone dependency test indicating greater dependency, women were significantly more dependent on smartphones than were men (mean smartphone dependency score: 50.7 vs. 56.0 for men and women, respectively, p<0.001). However, the amount of time spent using smartphones and the purpose of smartphone use affected smartphone dependency in both men and women. Particularly, when daily use time increased, smartphone dependency showed an increasing trend. Compared with times of use <2 hours vs. ≥6 hours, men scored 46.2 and 56.0 on the smartphone dependency test, while women scored 48.0 and 60.4, respectively (p<0.001). Finally, for both men and women, increases in smartphone dependency were associated with increased anxiety scores. With each one-point increase in smartphone dependency score, the risk of abnormal anxiety in men and women increased by 10.1% and 9.2%, respectively (p<0.001). Conclusion Among this group of university students in South Korea, smartphone dependency appeared to be associated with increased anxiety. Standards for smartphone use might help prevent deleterious health effects. PMID:27252561

Extreme late chronotypes and social jetlag challenged by Antarctic conditions in a population of university students from Uruguay

PubMed Central

Tassino, Bettina; Horta, Stefany; Santana, Noelia; Levandovski, Rosa; Silva, Ana

2016-01-01

In humans, a person’s chronotype depends on environmental cues and on individual characteristics, with late chronotypes prevailing in youth. Social jetlag (SJL), the misalignment between an individual׳s biological clock and social time, is higher in late chronotypes. Strong SJL is expected in Uruguayan university students with morning class schedules and very late entertainment activities. Sleep disorders have been reported in Antarctic inhabitants, that might be a response to the extreme environment or to the strictness of Antarctic life. We evaluated, for the first time in Uruguay, the chronotypes and SJL of 17 undergraduate students of the First Uruguayan Summer School on Antarctic Research, using Munich Chronotype Questionnaire (MCTQ) and sleep logs (SL) recorded during 3 phases: pre-Antarctic, Antarctic, and post-Antarctic. The midsleep point of free days corrected for sleep debt on work days (MSFsc,) was used as proxy of individuals’ chronotype, whose values (around 6 a.m.) are the latest ever reported. We found a SJL of around 2 h in average, which correlated positively with MSFsc, confirming that late chronotypes generate a higher sleep debt during weekdays. Midsleep point and sleep duration significantly decreased between pre-Antarctic and Antarctic phases, and sleep duration rebounded to significant higher values in the post-Antarctic phase. Waking time, but not sleep onset time, significantly varied among phases. This evidence suggests that sleep schedules more likely depended on the social agenda than on the environmental light–dark shifts. High motivation of students towards Antarctic activities likely induced a subjective perception of welfare non-dependent on sleep duration. PMID:27226819

Changes in aspects of social functioning depend upon prior changes in neurodisability in people with acquired brain injury undergoing post-acute neurorehabilitation.

PubMed

Fortune, Dónal G; Walsh, R Stephen; Waldron, Brian; McGrath, Caroline; Harte, Maurice; Casey, Sarah; McClean, Brian

2015-01-01

Post-acute community-based rehabilitation is effective in reducing disability. However, while social participation and quality of life are valued as distal outcomes of neurorehabilitation, it is often not possible to observe improvements on these outcomes within the limited time-frames used in most investigations of rehabilitation. The aim of the current study was to examine differences in the sequence of attainments for people with acquired brain injury (ABI) undergoing longer term post-acute neurorehabilitation. Participants with ABI who were referred to comprehensive home and community-based neurorehabilitation were assessed at induction to service, at 6 months and again at 1.5 years while still in service on the Mayo-Portland Adaptability Index (MPAI-4), Community Integration Questionnaire, Hospital Anxiety and Depression Scale, and World Health Organisation Quality of Life measure. At 6 months post-induction to service, significant differences were evident in MPAI abilities, adjustment, and total neurodisability; and in anxiety and depression. By contrast, there was no significant effect at 6 months on more socially oriented features of experience namely quality of life (QoL), Community Integration and Participation. Eighteen month follow-up showed continuation of the significant positive effects with the addition of QoL-related to physical health, Psychological health, Social aspects of QoL and Participation at this later time point. Regression analyses demonstrated that change in QoL and Participation were dependent upon prior changes in aspects of neurodisability. Age, severity or type of brain injury did not significantly affect outcome. Results suggest that different constructs may respond to neurorehabilitation at different time points in a dose effect manner, and that change in social aspects of experience may be dependent upon the specific nature of prior neurorehabilitation attainments.

Timing and Duration of Drug Exposure Affects Outcomes of a Drug-Nutrient Interaction During Ontogeny.

PubMed

Ling, Binbing; Aziz, Caroline; Wojnarowicz, Chris; Olkowski, Andrew; Alcorn, Jane

2010-10-14

Significant drug-nutrient interactions are possible when drugs and nutrients share the same absorption and disposition mechanisms. During postnatal development, the outcomes of drug-nutrient interactions may change with postnatal age since these processes undergo ontogenesis through the postnatal period. Our study investigated the dependence of a significant drug-nutrient interaction (cefepime-carnitine) on the timing and duration of drug exposure relative to postnatal age. Rat pups were administered cefepime (5 mg/kg) twice daily subcutaneously according to different dosing schedules (postnatal day 1-4, 1-8, 8-11, 8-20, or 1-20). Cefepime significantly reduced serum and heart L-carnitine levels in postnatal day 1-4, 1-8 and 8-11 groups and caused severe degenerative changes in ventricular myocardium in these groups. Cefepime also altered the ontogeny of several key L-carnitine homeostasis pathways. The qualitative and quantitative changes in levels of hepatic γ-butyrobetaine hydroxylase mRNA and activity, hepatic trimethyllysine hydroxlase mRNA, intestinal organic cation/carnitine transporter (Octn) mRNA, and renal Octn2 mRNA depended on when during postnatal development the cefepime exposure occurred and duration of exposure. Despite lower levels of heart L-carnitine in earlier postnatal groups, levels of carnitine palmitoyltransferase mRNA and activity, heart Octn2 mRNA and ATP levels in all treatment groups remained unchanged with cefepime exposure. However, changes in other high energy phosphate substrates were noted and reductions in the phosphocreatine/ATP ratio were found in rat pups with normal serum L-carnitine levels. In summary, our data suggest a significant drug-nutrient transport interaction in developing neonates, the nature of which depends on the timing and duration of exposure relative to postnatal age.

Timing and Duration of Drug Exposure Affects Outcomes of a Drug-Nutrient Interaction During Ontogeny

PubMed Central

Ling, Binbing; Aziz, Caroline; Wojnarowicz, Chris; Olkowski, Andrew; Alcorn, Jane

2010-01-01

Significant drug-nutrient interactions are possible when drugs and nutrients share the same absorption and disposition mechanisms. During postnatal development, the outcomes of drug-nutrient interactions may change with postnatal age since these processes undergo ontogenesis through the postnatal period. Our study investigated the dependence of a significant drug-nutrient interaction (cefepime-carnitine) on the timing and duration of drug exposure relative to postnatal age. Rat pups were administered cefepime (5 mg/kg) twice daily subcutaneously according to different dosing schedules (postnatal day 1-4, 1-8, 8-11, 8-20, or 1-20). Cefepime significantly reduced serum and heart L-carnitine levels in postnatal day 1-4, 1-8 and 8-11 groups and caused severe degenerative changes in ventricular myocardium in these groups. Cefepime also altered the ontogeny of several key L-carnitine homeostasis pathways. The qualitative and quantitative changes in levels of hepatic γ-butyrobetaine hydroxylase mRNA and activity, hepatic trimethyllysine hydroxlase mRNA, intestinal organic cation/carnitine transporter (Octn) mRNA, and renal Octn2 mRNA depended on when during postnatal development the cefepime exposure occurred and duration of exposure. Despite lower levels of heart L-carnitine in earlier postnatal groups, levels of carnitine palmitoyltransferase mRNA and activity, heart Octn2 mRNA and ATP levels in all treatment groups remained unchanged with cefepime exposure. However, changes in other high energy phosphate substrates were noted and reductions in the phosphocreatine/ATP ratio were found in rat pups with normal serum L-carnitine levels. In summary, our data suggest a significant drug-nutrient transport interaction in developing neonates, the nature of which depends on the timing and duration of exposure relative to postnatal age. PMID:27721360

Changes in aspects of social functioning depend upon prior changes in neurodisability in people with acquired brain injury undergoing post-acute neurorehabilitation

PubMed Central

Fortune, Dónal G.; Walsh, R. Stephen; Waldron, Brian; McGrath, Caroline; Harte, Maurice; Casey, Sarah; McClean, Brian

2015-01-01

Post-acute community-based rehabilitation is effective in reducing disability. However, while social participation and quality of life are valued as distal outcomes of neurorehabilitation, it is often not possible to observe improvements on these outcomes within the limited time-frames used in most investigations of rehabilitation. The aim of the current study was to examine differences in the sequence of attainments for people with acquired brain injury (ABI) undergoing longer term post-acute neurorehabilitation. Participants with ABI who were referred to comprehensive home and community-based neurorehabilitation were assessed at induction to service, at 6 months and again at 1.5 years while still in service on the Mayo-Portland Adaptability Index (MPAI-4), Community Integration Questionnaire, Hospital Anxiety and Depression Scale, and World Health Organisation Quality of Life measure. At 6 months post-induction to service, significant differences were evident in MPAI abilities, adjustment, and total neurodisability; and in anxiety and depression. By contrast, there was no significant effect at 6 months on more socially oriented features of experience namely quality of life (QoL), Community Integration and Participation. Eighteen month follow-up showed continuation of the significant positive effects with the addition of QoL-related to physical health, Psychological health, Social aspects of QoL and Participation at this later time point. Regression analyses demonstrated that change in QoL and Participation were dependent upon prior changes in aspects of neurodisability. Age, severity or type of brain injury did not significantly affect outcome. Results suggest that different constructs may respond to neurorehabilitation at different time points in a dose effect manner, and that change in social aspects of experience may be dependent upon the specific nature of prior neurorehabilitation attainments. PMID:26441744

Mean platelet volume (MPV) predicts middle distance running performance.

PubMed

Lippi, Giuseppe; Salvagno, Gian Luca; Danese, Elisa; Skafidas, Spyros; Tarperi, Cantor; Guidi, Gian Cesare; Schena, Federico

2014-01-01

Running economy and performance in middle distance running depend on several physiological factors, which include anthropometric variables, functional characteristics, training volume and intensity. Since little information is available about hematological predictors of middle distance running time, we investigated whether some hematological parameters may be associated with middle distance running performance in a large sample of recreational runners. The study population consisted in 43 amateur runners (15 females, 28 males; median age 47 years), who successfully concluded a 21.1 km half-marathon at 75-85% of their maximal aerobic power (VO2max). Whole blood was collected 10 min before the run started and immediately thereafter, and hematological testing was completed within 2 hours after sample collection. The values of lymphocytes and eosinophils exhibited a significant decrease compared to pre-run values, whereas those of mean corpuscular volume (MCV), platelets, mean platelet volume (MPV), white blood cells (WBCs), neutrophils and monocytes were significantly increased after the run. In univariate analysis, significant associations with running time were found for pre-run values of hematocrit, hemoglobin, mean corpuscular hemoglobin (MCH), red blood cell distribution width (RDW), MPV, reticulocyte hemoglobin concentration (RetCHR), and post-run values of MCH, RDW, MPV, monocytes and RetCHR. In multivariate analysis, in which running time was entered as dependent variable whereas age, sex, blood lactate, body mass index, VO2max, mean training regimen and the hematological parameters significantly associated with running performance in univariate analysis were entered as independent variables, only MPV values before and after the trial remained significantly associated with running time. After adjustment for platelet count, the MPV value before the run (p = 0.042), but not thereafter (p = 0.247), remained significantly associated with running performance. The significant association between baseline MPV and running time suggest that hyperactive platelets may exert some pleiotropic effects on endurance performance.

Structure and phylogenetic diversity of post-fire ectomycorrhizal communities of maritime pine.

PubMed

Rincón, A; Santamaría, B P; Ocaña, L; Verdú, M

2014-02-01

Environmental disturbances define the diversity and assemblage of species, affecting the functioning of ecosystems. Fire is a major disturbance of Mediterranean pine forests. Pines are highly dependent on the ectomycorrhizal (EM) fungal symbiosis, which is critical for tree recruitment under primary succession. To determine the effects of time since fire on the structure and recovery of EM fungal communities, we surveyed the young Pinus pinaster regenerate in three sites differing in the elapsed time after the last fire event. Pine roots were collected, and EM fungi characterized by sequencing the internal transcribed spacer (ITS) and the large subunit (LSU) regions of the nuclear ribosomal (nr)-DNA. The effects of the elapsed time after fire on the EM community structure (richness, presence/absence of fungi, phylogenetic diversity) and on soil properties were analysed.Fungal richness decreased with the elapsed time since the fire; although, the phylogenetic diversity of the EM community increased. Soil properties were different depending on the elapsed time after fire and particularly, the organic matter, carbon-to-nitrogen (C/N) ratio, nitrogen and iron significantly correlated with the assemblage of fungal species. Ascomycetes, particularly Tuberaceae and Pezizales, were significantly over-represented on saplings in the burned site. On seedlings, a significant over-representation of Rhizopogonaceae and Atheliaceae was observed in the most recently burned site, while other fungi (i.e. Cortinariaceae) were significantly under-represented. Our results are consistent with the hypothesis that fire can act as a selective agent by printing a phylogenetic signal on the EM fungal communities associated with naturally regenerated pines, pointing out to some groups as potential fire-adapted fungi.

Longitudinal costs of caring for people with Alzheimer's disease.

PubMed

Gillespie, Paddy; O'Shea, Eamon; Cullinan, John; Buchanan, Jacqui; Bobula, Joel; Lacey, Loretto; Gallagher, Damien; Mhaolain, Aine Ni; Lawlor, Brian

2015-05-01

There has been an increasing interest in the relationship between severity of disease and costs in the care of people with dementia. Much of the current evidence is based on cross-sectional data, suggesting the need to examine trends over time for this important and growing cohort of the population. This paper estimates resource use and costs of care based on longitudinal data for 72 people with dementia in Ireland. Data were collected from the Enhancing Care in Alzheimer's Disease (ECAD) study at two time points: baseline and follow-up, two years later. Patients' dependence on others was measured using the Dependence Scale (DS), while patient function was measured using the Disability Assessment for Dementia (DAD) scale. Univariate and multivariate analysis were used to explore the effects of a range of variables on formal and informal care costs. Total costs of formal and informal care over six months rose from €9,266 (Standard Deviation (SD): 12,947) per patient at baseline to €21,266 (SD: 26,883) at follow-up, two years later. This constituted a statistically significant (p = 0.0014) increase in costs over time, driven primarily by an increase in estimated informal care costs. In the multivariate analysis, a one-point increase in the DS score, that is a one-unit increase in patient's dependence on others, was associated with a 19% increase in total costs (p = 0.0610). Higher levels of dependence in people with Alzheimer's disease are significantly associated with increased costs of informal care as the disease progresses. Formal care services did not respond to increased dependence in people with dementia, leaving it to families to fill the caring gap, mainly through increased supervision with the progress of disease.

Direct comparison of two different mesalamine formulations for the maintenance of remission in patients with ulcerative colitis: A double-blind, randomized study

PubMed Central

Ito, Hiroaki; Iida, Mitsuo; Matsumoto, Takayuki; Suzuki, Yasuo; Aida, Yoshiyuki; Yoshida, Toyomitsu; Takano, Yuichi; Hibi, Toshifumi

2010-01-01

Background: Mesalamine has been used as the first-line medication for the treatment of ulcerative colitis (UC). We directly compared the efficacy and safety of two different mesalamine formulations in the maintenance of remission in patients with UC. Methods: In a multicenter, double-blind, randomized study, 131 patients with quiescent UC were assigned to two groups: 65 to receive a pH-dependent release formulation of mesalamine at 2.4 g/day (pH-2.4 g) and 66 to receive a time-dependent release formulation of mesalamine at 2.25 g/day (Time-2.25 g). Both formulations were administered three times daily for 48 weeks. The primary endpoint was the proportion of patients without bloody stools. Results: In the full analysis set (n = 130), the proportion of patients without bloody stools was 76.9% in the pH-2.4 g and 69.2% in the Time-2.25 g, demonstrating the noninferiority of pH-2.4 g to Time-2.25 g. No statistically significant difference in time to bloody stools was found between the two formulations (P = 0.27, log-rank test), but the time to bloody stools tended to be longer in pH-2.4 g compared to Time-2.25 g, and a similar trend was observed with regard to the time to relapse. No differences were observed between the safety profiles of the two formulations. Conclusions: The pH- and time-dependent release of mesalamine formulations were similarly safe and effective. Interestingly, the remission phase tended to be longer in the group that received the pH-dependent formulation compared to the group that received the time-dependent formulation (UMIN Clinical Trials Registry, no. C000000289). (Inflamm Bowel Dis 2010) PMID:20049949

Time-dependent probability density functions and information geometry in stochastic logistic and Gompertz models

NASA Astrophysics Data System (ADS)

Tenkès, Lucille-Marie; Hollerbach, Rainer; Kim, Eun-jin

2017-12-01

A probabilistic description is essential for understanding growth processes in non-stationary states. In this paper, we compute time-dependent probability density functions (PDFs) in order to investigate stochastic logistic and Gompertz models, which are two of the most popular growth models. We consider different types of short-correlated multiplicative and additive noise sources and compare the time-dependent PDFs in the two models, elucidating the effects of the additive and multiplicative noises on the form of PDFs. We demonstrate an interesting transition from a unimodal to a bimodal PDF as the multiplicative noise increases for a fixed value of the additive noise. A much weaker (leaky) attractor in the Gompertz model leads to a significant (singular) growth of the population of a very small size. We point out the limitation of using stationary PDFs, mean value and variance in understanding statistical properties of the growth in non-stationary states, highlighting the importance of time-dependent PDFs. We further compare these two models from the perspective of information change that occurs during the growth process. Specifically, we define an infinitesimal distance at any time by comparing two PDFs at times infinitesimally apart and sum these distances in time. The total distance along the trajectory quantifies the total number of different states that the system undergoes in time, and is called the information length. We show that the time-evolution of the two models become more similar when measured in units of the information length and point out the merit of using the information length in unifying and understanding the dynamic evolution of different growth processes.

Does the Availability of Parental Health Insurance Affect the College Enrollment Decision of Young Americans?

ERIC Educational Resources Information Center

Jung, Juergen; Hall, Diane M. Harnek; Rhoads, Thomas

2013-01-01

The present study examines whether the college enrollment decision of young individuals (student full-time, student part-time, and non-student) depends on health insurance coverage via a parent's family health plan. Our findings indicate that the availability of parental health insurance can have significant effects on the probability that a young…

The prevalence, predictors and associated health outcomes of high nicotine dependence using three measures among US smokers.

PubMed

Schnoll, Robert A; Goren, Amir; Annunziata, Kathy; Suaya, Jose A

2013-11-01

Using the Fagerström Test of Nicotine Dependence (FTND), the Heaviness of Smoking Index (HSI) and the time-to-first-cigarette (TTFC), this study estimated prevalence, evaluated optimal scale cut-offs, identified predictors and assessed potential impact on health, productivity and health-care use of high nicotine dependence among US smokers. This cross-sectional study used 2011 National Health and Wellness Survey data (n = 50 000). Nicotine dependence, demographic data, measures of health, productivity and health-care use and health attitudes were assessed. The prevalence of high nicotine dependence ranged from 23% (TTFC < 5 minutes) to 63.6% (TTFC < 30 minutes). Based on diagnostic accuracy, the cut-offs for high nicotine dependence using HSI and TTFC varied according to FTND cut-off: if FTND > 4, then HSI > 3 and TTFC < 30 minutes represented optimal cut-offs; if FTND > 5, HSI > 4 and TTFC < 5 minutes represented optimal cut-offs. Across all measures, high nicotine dependence was related significantly to being male, single, age 45-64 years and Caucasian; lower education; lack of health insurance; under/unemployment; comorbid respiratory or cardiovascular disease, diabetes or psychiatric illness; and lower rates of exercise and concern for weight control. Controlling for demographic variables and comorbid physical and psychiatric illness, high nicotine dependence, measured by FTND, HSI or TTFC, was associated significantly with reduced mental and physical quality of life, reduced work-place productivity and more health-care use. High nicotine dependence is associated with lower quality of life, lower work productivity and higher health-care use. The Heaviness of Smoking Index and the time-to-first-cigarette can provide useful screening measures of nicotine dependence in clinical and research settings. © 2013 Society for the Study of Addiction.

Motives for using: a comparison of prescription opioid, marijuana and cocaine dependent individuals.

PubMed

Hartwell, Karen J; Back, Sudie E; McRae-Clark, Aimee L; Shaftman, Stephanie R; Brady, Kathleen T

2012-04-01

Identification of the motives for drug use is critical to the development of effective interventions. Furthermore, consideration of the differences in motives for drug use across substance dependent populations may assist in tailoring interventions. To date, few studies have systematically compared motives for substance use across drug classes. The current study examined motives for drug use between non-treatment seeking individuals with current prescription opioid, marijuana, or cocaine dependence. Participants (N=227) completed the Inventory of Drug-Taking Situations (IDTS; Annis, Turner & Sklar,1997), which contains eight subscales assessing motives for drug use. The findings revealed that prescription opioid dependent individuals scored significantly higher than all other groups on the Physical Discomfort, Testing Personal Control and Conflict with Others subscales. Both the prescription opioid and cocaine dependent groups scored significantly higher than the marijuana group on the Urges or a Temptation to Use subscale. In contrast, marijuana dependent individuals scored highest on the Pleasant Emotions and Pleasant Times with Others subscales. The marked differences revealed in motives for drug use could be used in the development and implementation of specific treatment interventions for prescription opioid, marijuana and cocaine dependent individuals. Published by Elsevier Ltd.

Effects of observation heights and atmospheric wave evolution in sunspot seismology: a study using HMI and AIA (1600 A and 1700 A) data

NASA Astrophysics Data System (ADS)

Rajaguru, S. P.; Couvidaa, S.

2011-10-01

In achieving a high cadence and whole Sun coverage required of them, Doppler imagers such as HMI/SDO and MDI/SOHO necessarily forgo certain intricacies associated with magnetic and velocity field interactions, which require high (spectral) resolution spectropolarimetry for their accurate measurements with straightforward derivation of physical quantities (or observables). Magnetic field modified wave evolution, due to much reduced acoustic cut-off frequencies, in inclined field regions is one such situation. We first show, using a high cadence imaging spectropolarimetric observations made with IBIS instrument at NSO/Sac Peak, that significant contributions to seismically measured travel times arise from the line formation layers. We then present a comparative study of time-distance helioseismic measurements made over three sunspot regions using HMI and AIA (1600 A and 1700 A) data, which provide oscillation signals from three different heights. We bring out clear signals of height dependent wave phases and hence height dependent travel times. We further show that such signatures, from their differing contributions in one way travel times (in- or out-going wave travel times), could explain a significant part of the discrepancies between time-distance and other local helioseismic measurements and inferences.

Memory effects of Aronia melanocarpa fruit juice in a passive avoidance test in rats.

PubMed

Valcheva-Kuzmanova, Stefka V; Eftimov, Miroslav Tz; Tashev, Roman E; Belcheva, Iren P; Belcheva, Stiliana P

2014-01-01

To study the effect of Aronia melanocarpa fruit juice on memory in male Wistar rats. The juice was administered orally for 7, 14, 21 and 30 days at doses of 2.5 ml/kg, 5 ml/kg and 10 ml/kg. Memory was assessed in the one-way passive avoidance task (step through) which consisted of one training session and two retention tests (3 hours and 24 hours after training). The variables measured were the latency time to step into the dark compartment of the apparatus and the learning criterion (remaining in the illuminated compartment for at least 180 sec). Oral administration of Aronia melanocarpa fruit juice for 7 and 14 days resulted in a dose-dependent tendency to increase the latency time and the learning criterion compared to saline-treated controls but the effect failed to reach statistical significance. After 21 days of treatment, the juice dose-dependently prolonged the latency time at the retention tests, the effect being significant at doses of 5 ml/kg and 10 ml/kg. Applied for 30 days, the juice in all the tested doses increased significantly the latency time at the retention tests and the dose of 10 ml/kg significantly increased the percentage of rats reaching the learning criterion. These findings suggest that Aronia melanocarpa fruit juice could improve memory in rats. The effect is probably due to the polyphenolic ingredients of the juice which have been shown to be involved in learning and memory processes.

Temperature-dependent inotropic and lusitropic indices based on half-logistic time constants for four segmental phases in isovolumic left ventricular pressure-time curve in excised, cross-circulated canine heart.

PubMed

Mizuno, Ju; Mohri, Satoshi; Yokoyama, Takeshi; Otsuji, Mikiya; Arita, Hideko; Hanaoka, Kazuo

2017-02-01

Varying temperature affects cardiac systolic and diastolic function and the left ventricular (LV) pressure-time curve (PTC) waveform that includes information about LV inotropism and lusitropism. Our proposed half-logistic (h-L) time constants obtained by fitting using h-L functions for four segmental phases (Phases I-IV) in the isovolumic LV PTC are more useful indices for estimating LV inotropism and lusitropism during contraction and relaxation periods than the mono-exponential (m-E) time constants at normal temperature. In this study, we investigated whether the superiority of the goodness of h-L fits remained even at hypothermia and hyperthermia. Phases I-IV in the isovolumic LV PTCs in eight excised, cross-circulated canine hearts at 33, 36, and 38 °C were analyzed using h-L and m-E functions and the least-squares method. The h-L and m-E time constants for Phases I-IV significantly shortened with increasing temperature. Curve fitting using h-L functions was significantly better than that using m-E functions for Phases I-IV at all temperatures. Therefore, the superiority of the goodness of h-L fit vs. m-E fit remained at all temperatures. As LV inotropic and lusitropic indices, temperature-dependent h-L time constants could be more useful than m-E time constants for Phases I-IV.

Physiologic volume of phosphorus during hemodialysis: predictions from a pseudo one-compartment model.

PubMed

Leypoldt, John K; Akonur, Alp; Agar, Baris U; Culleton, Bruce F

2012-10-01

The kinetics of plasma phosphorus concentrations during hemodialysis (HD) are complex and cannot be described by conventional one- or two-compartment kinetic models. It has recently been shown by others that the physiologic (or apparent distribution) volume for phosphorus (Vr-P) increases with increasing treatment time and shows a large variation among patients treated by thrice weekly and daily HD. Here, we describe the dependence of Vr-P on treatment time and predialysis plasma phosphorus concentration as predicted by a novel pseudo one-compartment model. The kinetics of plasma phosphorus during conventional and six times per week daily HD were simulated as a function of treatment time per session for various dialyzer phosphate clearances and patient-specific phosphorus mobilization clearances (K(M)). Vr-P normalized to extracellular volume from these simulations were reported and compared with previously published empirical findings. Simulated results were relatively independent of dialyzer phosphate clearance and treatment frequency. In contrast, Vr-P was strongly dependent on treatment time per session; the increase in Vr-P with treatment time was larger for higher values of K(M). Vr-P was inversely dependent on predialysis plasma phosphorus concentration. There was significant variation among predicted Vr-P values, depending largely on the value of K(M). We conclude that a pseudo one-compartment model can describe the empirical dependence of the physiologic volume of phosphorus on treatment time and predialysis plasma phosphorus concentration. Further, the variation in physiologic volume of phosphorus among HD patients is largely due to differences in patient-specific phosphorus mobilization clearance. © 2012 The Authors. Hemodialysis International © 2012 International Society for Hemodialysis.

Aggregation increases prey survival time in group chase and escape

NASA Astrophysics Data System (ADS)

Yang, Sicong; Jiang, Shijie; Jiang, Li; Li, Geng; Han, Zhangang

2014-08-01

Recently developed chase-and-escape models have addressed a fascinating pursuit-and-evasion problem that may have both theoretical significance and potential applications. We introduce three aggregation strategies for the prey in a group chase model on a lattice. Simulation results show that aggregation dramatically increases the group survival time, even allowing immortal prey. The average survival time τ and the aggregation probability P have a power-law dependence of \\tau \\sim {{(1-P)}^{-1}} for P\\in [0.9,0.997]. With increasing numbers of predators, there is still a phase transition. When the number of predators is less than the critical point value, the prey group survival time increases significantly.

Spatially varying density dependence drives a shifting mosaic of survival in a recovering apex predator (Canis lupus).

PubMed

O'Neil, Shawn T; Bump, Joseph K; Beyer, Dean E

2017-11-01

Understanding landscape patterns in mortality risk is crucial for promoting recovery of threatened and endangered species. Humans affect mortality risk in large carnivores such as wolves ( Canis lupus ), but spatiotemporally varying density dependence can significantly influence the landscape of survival. This potentially occurs when density varies spatially and risk is unevenly distributed. We quantified spatiotemporal sources of variation in survival rates of gray wolves ( C. lupus ) during a 21-year period of population recovery in the Upper Peninsula of Michigan, USA. We focused on mapping risk across time using Cox Proportional Hazards (CPH) models with time-dependent covariates, thus exploring a shifting mosaic of survival. Extended CPH models and time-dependent covariates revealed influences of seasonality, density dependence and experience, as well as individual-level factors and landscape predictors of risk. We used results to predict the shifting landscape of risk at the beginning, middle, and end of the wolf recovery time series. Survival rates varied spatially and declined over time. Long-term change was density-dependent, with landscape predictors such as agricultural land cover and edge densities contributing negatively to survival. Survival also varied seasonally and depended on individual experience, sex, and resident versus transient status. The shifting landscape of survival suggested that increasing density contributed to greater potential for human conflict and wolf mortality risk. Long-term spatial variation in key population vital rates is largely unquantified in many threatened, endangered, and recovering species. Variation in risk may indicate potential for source-sink population dynamics, especially where individuals preemptively occupy suitable territories, which forces new individuals into riskier habitat types as density increases. We encourage managers to explore relationships between adult survival and localized changes in population density. Density-dependent risk maps can identify increasing conflict areas or potential habitat sinks which may persist due to high recruitment in adjacent habitats.

Application of Different Statistical Techniques in Integrated Logistics Support of the International Space Station Alpha

NASA Technical Reports Server (NTRS)

Sepehry-Fard, F.; Coulthard, Maurice H.

1995-01-01

The process to predict the values of the maintenance time dependent variable parameters such as mean time between failures (MTBF) over time must be one that will not in turn introduce uncontrolled deviation in the results of the ILS analysis such as life cycle cost spares calculation, etc. A minor deviation in the values of the maintenance time dependent variable parameters such as MTBF over time will have a significant impact on the logistics resources demands, International Space Station availability, and maintenance support costs. It is the objective of this report to identify the magnitude of the expected enhancement in the accuracy of the results for the International Space Station reliability and maintainability data packages by providing examples. These examples partially portray the necessary information hy evaluating the impact of the said enhancements on the life cycle cost and the availability of the International Space Station.

Continuous-Time Random Walk with multi-step memory: an application to market dynamics

NASA Astrophysics Data System (ADS)

Gubiec, Tomasz; Kutner, Ryszard

2017-11-01

An extended version of the Continuous-Time Random Walk (CTRW) model with memory is herein developed. This memory involves the dependence between arbitrary number of successive jumps of the process while waiting times between jumps are considered as i.i.d. random variables. This dependence was established analyzing empirical histograms for the stochastic process of a single share price on a market within the high frequency time scale. Then, it was justified theoretically by considering bid-ask bounce mechanism containing some delay characteristic for any double-auction market. Our model appeared exactly analytically solvable. Therefore, it enables a direct comparison of its predictions with their empirical counterparts, for instance, with empirical velocity autocorrelation function. Thus, the present research significantly extends capabilities of the CTRW formalism. 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.

Applying the relaxation model of interfacial heat transfer to calculate the liquid outflow with supercritical initial parameters

NASA Astrophysics Data System (ADS)

Alekseev, M. V.; Vozhakov, I. S.; Lezhnin, S. I.; Pribaturin, N. A.

2017-09-01

A comparative numerical simulation of the supercritical fluid outflow on the thermodynamic equilibrium and non-equilibrium relaxation models of phase transition for different times of relaxation has been performed. The model for the fixed relaxation time based on the experimentally determined radius of liquid droplets was compared with the model of dynamically changing relaxation time, calculated by the formula (7) and depending on local parameters. It is shown that the relaxation time varies significantly depending on the thermodynamic conditions of the two-phase medium in the course of outflowing. The application of the proposed model with dynamic relaxation time leads to qualitatively correct results. The model can be used for both vaporization and condensation processes. It is shown that the model can be improved on the basis of processing experimental data on the distribution of the droplet sizes formed during the breaking up of the liquid jet.

The time and temperature dependence of the thermoelectric properties of silicon-germanium alloy

NASA Technical Reports Server (NTRS)

Raag, V.

1975-01-01

Experimental data on the electrical resistivity and Seebeck coefficient of n-type and p-type silicon-germanium alloys are analyzed in terms of a solid-state dopant precipitation model proposed by Lifshitz and Slyozov (1961). Experimental findings on the time and temperature dependence of the thermal conductivity of these two types of alloy indicate that the thermal conductivity of silicon-germanium alloys changes with time, contrary to previous hypothesis. A preliminary model is presented which stipulates that the observed thermal conductivity decrease in silicon-germanium alloys is due partly to dopant precipitation underlying the electrical property changes and partly to enhanced alloying of the material. It is significant that all three properties asymptotically approach equilibrium values with time. Total characterization of these properties will enable the time change to be fully compensated in the design of a thermoelectric device employing silicon-germanium alloys.

Obstetric significance of fetal craniofacial duplication. A case report.

PubMed

Chervenak, F A; Pinto, M M; Heller, C I; Norooz, H

1985-01-01

Craniofacial duplication (diprosopus) is a rare form of conjoined twins. Whenever fetal hydrocephalus is diagnosed, a careful search for other anomalies, such as diprosopus, is mandatory. The obstetric management depends upon the time of the diagnosis.

CO2 convective dissolution controlled by temporal changes in free-phase CO2 properties

NASA Astrophysics Data System (ADS)

Jafari Raad, S. M.; Emami-Meybodi, H.; Hassanzadeh, H.

2017-12-01

Understanding the factors that control CO2 convective dissolution, which is one of the permanent trapping mechanisms, in the deep saline aquifer is crucial in the long-term fate of the injected CO2. The present study investigates the effects of temporal changes in the solubility of CO2 at the free-phase CO2/brine interface on the onset of natural convection and the subsequent convective mixing by conducting linear stability analyses (LSA) and direct numerical simulations (DNS). A time-dependent concentration boundary is considered for the free-phase CO2/brine interface where the CO2 concentration first decreases with the time and then remains constant. The LSA results show that the temporal variation in the concentration increases the onset of natural convection up to two orders of magnitude. In addition, the critical Rayleigh number significantly increases as CO2 concentration decreases. In other words, size and pressure of the injected CO2 affect the commencement of convective mixing. Based on LSA results, several scaling relations are proposed to correlate critical Rayleigh number, critical time, and its corresponding wavenumbers with time-dependent boundary's parameters, such as concentration decline rate and equilibrium concentration ratio. The DNS results reveal that the convective fingering patterns are significantly influenced by the variation of CO2 concentration at the interface. These findings improve our understanding of CO2 solubility trapping and are particularly important in estimation of potential storage capacity, risk assessment, and storage sites characterization and screening. Keywords: CO2 sequestration; natural convection; solubility trapping; time-dependent boundary condition; numerical simulation; stability analysis

Effects of Moist Convection on Hurricane Predictability

NASA Technical Reports Server (NTRS)

Zhang, Fuqing; Sippel, Jason A.

2008-01-01

This study exemplifies inherent uncertainties in deterministic prediction of hurricane formation and intensity. Such uncertainties could ultimately limit the predictability of hurricanes at all time scales. In particular, this study highlights the predictability limit due to the effects on moist convection of initial-condition errors with amplitudes far smaller than those of any observation or analysis system. Not only can small and arguably unobservable differences in the initial conditions result in different routes to tropical cyclogenesis, but they can also determine whether or not a tropical disturbance will significantly develop. The details of how the initial vortex is built can depend on chaotic interactions of mesoscale features, such as cold pools from moist convection, whose timing and placement may significantly vary with minute initial differences. Inherent uncertainties in hurricane forecasts illustrate the need for developing advanced ensemble prediction systems to provide event-dependent probabilistic forecasts and risk assessment.

Collision dynamics of H+ + N2 at low energies based on time-dependent density-functional theory

NASA Astrophysics Data System (ADS)

Yu, W.; Zhang, Y.; Zhang, F. S.; Hutton, R.; Zou, Y.; Gao, C.-Z.; Wei, B.

2018-02-01

Using time-dependent density-functional theory at the level of local density approximation augmented by a self-interaction correction and coupled non-adiabatically to molecular dynamics, we study, from a theoretical perspective, scattering dynamics of the proton in collisions with the N2 molecule at 30 eV. Nine different collision configurations are employed to analyze the proton energy loss spectra, electron depletion, scattering angles and self-interaction effects. Our results agree qualitatively with the experimental data and previous theoretical calculations. The discrepancies are ascribed to the limitation of the theoretical models in use. We find that self-interaction effects can significantly influence the electron capture and the excited diatomic vibrational motion, which is in consistent with other calculations. In addition, it is found that the molecular structure can be readily retrieved from the proton energy loss spectra due to a significant momentum transfer in head-on collisions.

Time dependent pre-treatment EPID dosimetry for standard and FFF VMAT.

PubMed

Podesta, Mark; Nijsten, Sebastiaan M J J G; Persoon, Lucas C G G; Scheib, Stefan G; Baltes, Christof; Verhaegen, Frank

2014-08-21

Methods to calibrate Megavoltage electronic portal imaging devices (EPIDs) for dosimetry have been previously documented for dynamic treatments such as intensity modulated radiotherapy (IMRT) using flattened beams and typically using integrated fields. While these methods verify the accumulated field shape and dose, the dose rate and differential fields remain unverified. The aim of this work is to provide an accurate calibration model for time dependent pre-treatment dose verification using amorphous silicon (a-Si) EPIDs in volumetric modulated arc therapy (VMAT) for both flattened and flattening filter free (FFF) beams. A general calibration model was created using a Varian TrueBeam accelerator, equipped with an aS1000 EPID, for each photon spectrum 6 MV, 10 MV, 6 MV-FFF, 10 MV-FFF. As planned VMAT treatments use control points (CPs) for optimization, measured images are separated into corresponding time intervals for direct comparison with predictions. The accuracy of the calibration model was determined for a range of treatment conditions. Measured and predicted CP dose images were compared using a time dependent gamma evaluation using criteria (3%, 3 mm, 0.5 sec). Time dependent pre-treatment dose verification is possible without an additional measurement device or phantom, using the on-board EPID. Sufficient data is present in trajectory log files and EPID frame headers to reliably synchronize and resample portal images. For the VMAT plans tested, significantly more deviation is observed when analysed in a time dependent manner for FFF and non-FFF plans than when analysed using only the integrated field. We show EPID-based pre-treatment dose verification can be performed on a CP basis for VMAT plans. This model can measure pre-treatment doses for both flattened and unflattened beams in a time dependent manner which highlights deviations that are missed in integrated field verifications.

Two-stage unified stretched-exponential model for time-dependence of threshold voltage shift under positive-bias-stresses in amorphous indium-gallium-zinc oxide thin-film transistors

NASA Astrophysics Data System (ADS)

Jeong, Chan-Yong; Kim, Hee-Joong; Hong, Sae-Young; Song, Sang-Hun; Kwon, Hyuck-In

2017-08-01

In this study, we show that the two-stage unified stretched-exponential model can more exactly describe the time-dependence of threshold voltage shift (ΔV TH) under long-term positive-bias-stresses compared to the traditional stretched-exponential model in amorphous indium-gallium-zinc oxide (a-IGZO) thin-film transistors (TFTs). ΔV TH is mainly dominated by electron trapping at short stress times, and the contribution of trap state generation becomes significant with an increase in the stress time. The two-stage unified stretched-exponential model can provide useful information not only for evaluating the long-term electrical stability and lifetime of the a-IGZO TFT but also for understanding the stress-induced degradation mechanism in a-IGZO TFTs.

Chronic Ethanol Exposure Produces Time- and Brain Region-Dependent Changes in Gene Coexpression Networks

PubMed Central

Osterndorff-Kahanek, Elizabeth A.; Becker, Howard C.; Lopez, Marcelo F.; Farris, Sean P.; Tiwari, Gayatri R.; Nunez, Yury O.; Harris, R. Adron; Mayfield, R. Dayne

2015-01-01

Repeated ethanol exposure and withdrawal in mice increases voluntary drinking and represents an animal model of physical dependence. We examined time- and brain region-dependent changes in gene coexpression networks in amygdala (AMY), nucleus accumbens (NAC), prefrontal cortex (PFC), and liver after four weekly cycles of chronic intermittent ethanol (CIE) vapor exposure in C57BL/6J mice. Microarrays were used to compare gene expression profiles at 0-, 8-, and 120-hours following the last ethanol exposure. Each brain region exhibited a large number of differentially expressed genes (2,000-3,000) at the 0- and 8-hour time points, but fewer changes were detected at the 120-hour time point (400-600). Within each region, there was little gene overlap across time (~20%). All brain regions were significantly enriched with differentially expressed immune-related genes at the 8-hour time point. Weighted gene correlation network analysis identified modules that were highly enriched with differentially expressed genes at the 0- and 8-hour time points with virtually no enrichment at 120 hours. Modules enriched for both ethanol-responsive and cell-specific genes were identified in each brain region. These results indicate that chronic alcohol exposure causes global ‘rewiring‘ of coexpression systems involving glial and immune signaling as well as neuronal genes. PMID:25803291

Search for time modulations in the decay constant of 40K and 226Ra at the underground Gran Sasso Laboratory

NASA Astrophysics Data System (ADS)

Bellotti, E.; Broggini, C.; Di Carlo, G.; Laubenstein, M.; Menegazzo, R.

2018-05-01

Time modulations at per mil level have been reported to take place in the decay constant of several nuclei with period of one year (most cases) but also of about one month or one day. On the other hand, experiments with similar or better sensitivity have been unable to detect any modulation. In this letter we give the results of the activity study of two different sources: 40K and 226Ra. The two gamma spectrometry experiments have been performed underground at the Gran Sasso Laboratory, this way suppressing the time dependent cosmic ray background. Briefly, our measurements reached the sensitivity of 3.4 and 3.5 parts over 106 for 40K and 226Ra, respectively (1 sigma) and they do not show any statistically significant evidence of time dependence in the decay constant. We also give the results of the activity measurement at the time of the two strong X-class solar flares which took place in September 2017. Our data do not show any unexpected time dependence in the decay rate of 40K in correspondence with the two flares. To the best of our knowledge, these are the most precise and accurate results on the stability of the decay constant as function of time.

High frequency measures of OHC nonlinear capacitance (NLC) and their significance: Why measures stray away from predictions

NASA Astrophysics Data System (ADS)

Santos-Sacchi, Joseph

2018-05-01

Measures of membrane capacitance (Cm) can be used to assess important characteristics of voltage-dependent membrane proteins (e.g., channels and transporters). In particular, a protein's time-dependent voltage-sensor charge movement is equivalently represented as a frequency-dependent component of Cm, telling much about the kinetics of the protein's conformational behavior. Recently, we have explored the frequency dependence of OHC voltage-dependent capacitance (aka nonlinear capacitance, NLC) to query rates of conformational switching within prestin (SLC26a5), the cell's lateral membrane molecular motor 1. Following removal of confounding stray capacitance effects, high frequency Cm measures using wide-band stimuli accurately reveal unexpected low pass behavior in prestin's molecular motions.

Frequency Dependence of Helioseismic Measurements of the Center-to-Limb Effect and Flow-induced Travel-time Shifts

NASA Astrophysics Data System (ADS)

Chen, Ruizhu; Zhao, Junwei

2018-02-01

Time–distance helioseismology measures acoustic travel times to infer the structure and flow field of the solar interior; however, both the mean travel times and the travel-time shifts suffer systematic center-to-limb variations, which complicate the interpretation and inversions of the time–distance measurements. In particular, the center-to-limb variation in travel-time shifts (CtoL effect) has a significant impact on the inference of the Sun’s meridional circulation, and needs to be removed from the helioseismic measurements, although the observational properties and the physical cause of the CtoL effect have yet to be investigated. In this study, we measure the CtoL effect in the frequency domain using Doppler-velocity data from the Solar Dynamics Observatory/Helioseismic and Magnetic Imager, and study its properties as a function of disk-centric distance, travel distance, and frequency of acoustic waves. It is found that the CtoL effect has a significant frequency dependence—it reverses sign at a frequency around 5.4 mHz and reaches maximum at around 4.0 mHz before the sign reversal. The tendency of frequency dependence varies with disk-centric distance in a way that both the sign-reversal frequency and the maximum-value frequency decrease closer to the limb. The variation tendency does not change with travel distance, but the variation magnitude is approximately proportional to travel distance. For comparison, the flow-induced travel-time shifts show little frequency dependence. These observational properties provide more clues on the nature of the CtoL effect, and also possibly lead to new ways of effect-removal for a more robust determination of the deep meridional flow.

How do dual practitioners divide their time? The cases of three African capital cities.

PubMed

McPake, Barbara; Russo, Giuliano; Tseng, Fu-Min

2014-12-01

Health professionals dual practice has received increasing attention, particularly in the context of the universal health coverage movement. This paper explores the determinants of doctors' choices to become a dual practitioner and of dual practitioners' choices to allocate time to the private sector in the capital cities of Mozambique, Guinea Bissau and Cape Verde. The data are drawn from a survey conducted in 2012 among 329 physicians. We use a two-part model to analyse the decision of both public and private practitioners to become dual practitioners, and to allocate time between public and private sectors. We impute potential earnings in public and private practice by using nearest-neighbour propensity score matching. Our results show that hourly wage in the private sector, number of dependents, length of time as a physician, work outside city, and being a specialist with or without technology all have a positive association with the probability of being a dual physician, while number of dependents displays a negative sign. Level of salaries in the public sector are not associated with dual practice engagement, with important implications for attempts aimed at retaining professionals in the public sector through wage increases. As predicted by theory that recognises doctors' role in price setting, earnings rates are not significant predictors of private sector time allocation; personal characteristics of physicians appear more important, such as age, number of dependents, specialist without technology, specialist with technology, and three reasons for not working more hours in the private sector. Answers to questions about the factors that limit working hours in the private sector have significant predictive power, suggesting that type of employment in the private sector may be an underlying determinant of both dual practice engagement and time allocation decisions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of methylmercury and alcohol exposure in Drosophila melanogaster: Potential risks in neurodevelopmental disorders.

PubMed

Chauhan, Ved; Chauhan, Abha

2016-06-01

Extensive evidence suggests the role of oxidative stress in autism and other neurodevelopmental disorders. In this study, we investigated whether methylmercury (MeHg) and/or alcohol exposure has deleterious effects in Drosophila melanogaster (fruit flies). A diet containing different concentrations of MeHg in Drosophila induced free radical generation and increased lipid peroxidation (markers of oxidative stress) in a dose-dependent manner. This effect of MeHg on oxidative stress was enhanced by further exposure to alcohol. It was observed that alcohol alone could also induce free radical generation in flies. After alcohol exposure, MeHg did not affect the immobilization of flies, but it increased the recovery time in a concentration-dependent manner. MeHg significantly inhibited the activity of alcohol dehydrogenase (ADH) in a dose-dependent manner. Linear regression analysis showed a significant negative correlation between ADH activity and recovery time upon alcohol exposure in the flies fed a diet with MeHg. This relationship between ADH activity and recovery time after alcohol exposure was confirmed by adding 4-methyl pyrazole (an inhibitor of ADH) to the diet for the flies. These results suggest that consumption of alcohol by pregnant mothers who are exposed to MeHg may lead to increased oxidative stress and to increased length of time for alcohol clearance, which may have a direct impact on the development of the fetus, thereby increasing the risk of neurodevelopmental disorders. Published by Elsevier Ltd.

Time-Dependent Stress Rupture Strength Degradation of Hi-Nicalon Fiber-Reinforced Silicon Carbide Composites at Intermediate Temperatures

NASA Technical Reports Server (NTRS)

Sullivan, Roy M.

2016-01-01

The stress rupture strength of silicon carbide fiber-reinforced silicon carbide composites with a boron nitride fiber coating decreases with time within the intermediate temperature range of 700 to 950 degree Celsius. Various theories have been proposed to explain the cause of the time-dependent stress rupture strength. The objective of this paper is to investigate the relative significance of the various theories for the time-dependent strength of silicon carbide fiber-reinforced silicon carbide composites. This is achieved through the development of a numerically based progressive failure analysis routine and through the application of the routine to simulate the composite stress rupture tests. The progressive failure routine is a time-marching routine with an iterative loop between a probability of fiber survival equation and a force equilibrium equation within each time step. Failure of the composite is assumed to initiate near a matrix crack and the progression of fiber failures occurs by global load sharing. The probability of survival equation is derived from consideration of the strength of ceramic fibers with randomly occurring and slow growing flaws as well as the mechanical interaction between the fibers and matrix near a matrix crack. The force equilibrium equation follows from the global load sharing presumption. The results of progressive failure analyses of the composite tests suggest that the relationship between time and stress-rupture strength is attributed almost entirely to the slow flaw growth within the fibers. Although other mechanisms may be present, they appear to have only a minor influence on the observed time-dependent behavior.

Time-dependent Gas-liquid Interaction in Molecular-sized Nanopores

PubMed Central

Sun, Yueting; Li, Penghui; Qiao, Yu; Li, Yibing

2014-01-01

Different from a bulk phase, a gas nanophase can have a significant effect on liquid motion. Herein we report a series of experimental results on molecular behaviors of water in a zeolite β of molecular-sized nanopores. If sufficient time is provided, the confined water molecules can be “locked” inside a nanopore; otherwise, gas nanophase provides a driving force for water “outflow”. This is due to the difficult molecular site exchanges and the relatively slow gas-liquid diffusion in the nanoenvironment. Depending on the loading rate, the zeolite β/water system may exhibit either liquid-spring or energy-absorber characteristics. PMID:25293525

Analysis of Accelerometer Data from a Woven Inflatable Creep Burst Test

NASA Technical Reports Server (NTRS)

James, George H.; Grygier, Michael; Selig, Molly M.

2015-01-01

Accelerometers were used to montor an inflatable test article during a creep test to failure. The test article experienced impulse events that were classified based on the response of the sensors and their time-dependent manifestation. These impulse events required specialized techniques to process the structural dynamics data. However, certain phenomena were defined as worthy of additional study. An assessment of one phenomena (a frequency near 1000Hz) showed a time dependent frequency and an amplitude that increased significantly near the end of the test. Hence, these observations are expected to drive future understanding of and utility in inflatable space structures.

Time-resolved photoluminescence investigation of (Mg, Zn) O alloy growth on a non-polar plane

NASA Astrophysics Data System (ADS)

Mohammed Ali, Mohammed Jassim; Chauveau, J. M.; Bretagnon, T.

2018-04-01

Excitons recombination dynamics in ZnMgO alloy have been studied by time-resolved photoluminescence according to temperature. At low temperature, localisation effects of the exciton are found to play a significant role. The photoluminescence (PL) decays are bi-exponential. The short lifetime has a constant value, whereas the long lifetime shows a dependency with temperature. For temperature higher than 100 K the declines show a mono-exponential decay. The PL declines are dominated by non-radiative process at temperatures above 150 K. The PL lifetime dependancy with temperature is analysed using a model including localisation effects and non-radiative recombinations.

Evaluation of coagulation parameters and liver enzymes among alcohol drinkers in Port Harcourt, Nigeria.

PubMed

Adias, Teddy Charles; Egerton, Everton; Erhabor, Osaro

2013-01-01

Alcohol is a major contributor to the global burden of disease, disability, and death in high, middle, and low-income countries. Harmful use of alcohol is one of the main factors contributing to premature deaths and avoidable disease burden worldwide and has a major impact on public health. The aim of this present cross-sectional study was to investigate the effect of alcohol consumption on coagulation parameters and liver enzymes of subjects in Port Harcourt, Nigeria. Two hundred adults consisting of 120 alcohol dependent subjects and 80 age, gender-matched nondrinkers aged 25-65 years (mean age 45.25 ± 11.50 years) were enrolled in this study. Of the 120 chronic alcohol drinkers, 37 were dependent on local dry gin, while 83 were dependent on other alcoholic beverages. The mean values of the liver enzymes, aspartate aminotransferase and gamma glutamyl transferase, were significantly higher (P = 0.002 and P = 0.02 respectively) among the chronic alcohol consumers compared with their nondrinker counterparts. Although the value of alanine aminotransferase was higher in the chronic drinkers, it did not reveal any significant difference (P = 0.11). The coagulation parameters, prothrombin time and activated partial thromboplastin time were investigated among chronic drinkers and nondrinkers. The mean value of prothrombin time and activated partial thromboplastin time was significantly higher in the chronic alcohol drinkers compared to the nondrinkers (P = 0.04 and P = 0.02 respectively). We observed a positive and significant correlation between values of liver enzymes, serum gamma glutamyl transferase and aspartate aminotransferase, and values of prothrombin time among alcohol consumers (r = 0.72 and r = 0.68 respectively). The implementation of policies to target harm reduction strategies among alcoholics is urgently needed, alongside the building of a strong base of public awareness and community support required for the continuity and sustainability of alcohol policies. There is also the need for the Nigerian government to enforce tighter regulations and restrictions on the production and distribution of alcoholic beverages to reduce harmful use, and protect young people and other vulnerable groups.

Evaluation of coagulation parameters and liver enzymes among alcohol drinkers in Port Harcourt, Nigeria

PubMed Central

Adias, Teddy Charles; Egerton, Everton; Erhabor, Osaro

2013-01-01

Alcohol is a major contributor to the global burden of disease, disability, and death in high, middle, and low-income countries. Harmful use of alcohol is one of the main factors contributing to premature deaths and avoidable disease burden worldwide and has a major impact on public health. The aim of this present cross-sectional study was to investigate the effect of alcohol consumption on coagulation parameters and liver enzymes of subjects in Port Harcourt, Nigeria. Two hundred adults consisting of 120 alcohol dependent subjects and 80 age, gender-matched nondrinkers aged 25–65 years (mean age 45.25 ± 11.50 years) were enrolled in this study. Of the 120 chronic alcohol drinkers, 37 were dependent on local dry gin, while 83 were dependent on other alcoholic beverages. The mean values of the liver enzymes, aspartate aminotransferase and gamma glutamyl transferase, were significantly higher (P = 0.002 and P = 0.02 respectively) among the chronic alcohol consumers compared with their nondrinker counterparts. Although the value of alanine aminotransferase was higher in the chronic drinkers, it did not reveal any significant difference (P = 0.11). The coagulation parameters, prothrombin time and activated partial thromboplastin time were investigated among chronic drinkers and nondrinkers. The mean value of prothrombin time and activated partial thromboplastin time was significantly higher in the chronic alcohol drinkers compared to the nondrinkers (P = 0.04 and P = 0.02 respectively). We observed a positive and significant correlation between values of liver enzymes, serum gamma glutamyl transferase and aspartate aminotransferase, and values of prothrombin time among alcohol consumers (r = 0.72 and r = 0.68 respectively). The implementation of policies to target harm reduction strategies among alcoholics is urgently needed, alongside the building of a strong base of public awareness and community support required for the continuity and sustainability of alcohol policies. There is also the need for the Nigerian government to enforce tighter regulations and restrictions on the production and distribution of alcoholic beverages to reduce harmful use, and protect young people and other vulnerable groups. PMID:23807858

Trends in the suspended-sediment yields of coastal rivers of northern California, 1955–2010

USGS Publications Warehouse

Warrick, J.A.; Madej, Mary Ann; Goñi, M. A.; Wheatcroft, R.A.

2013-01-01

Time-dependencies of suspended-sediment discharge from six coastal watersheds of northern California – Smith River, Klamath River, Trinity River, Redwood Creek, Mad River, and Eel River – were evaluated using monitoring data from 1955 to 2010. Suspended-sediment concentrations revealed time-dependent hysteresis and multi-year trends. The multi-year trends had two primary patterns relative to river discharge: (i) increases in concentration resulting from both land clearing from logging and the flood of record during December 1964 (water year 1965), and (ii) continual decreases in concentration during the decades following this flood. Data from the Eel River revealed that changes in suspended-sediment concentrations occurred for all grain-size fractions, but were most pronounced for the sand fraction. Because of these changes, the use of bulk discharge-concentration relationships (i.e., “sediment rating curves”) without time-dependencies in these relationships resulted in substantial errors in sediment load estimates, including 2.5-fold over-prediction of Eel River sediment loads since 1979. We conclude that sediment discharge and sediment discharge relationships (such as sediment rating curves) from these coastal rivers have varied substantially with time in response to land use and climate. Thus, the use of historical river sediment data and sediment rating curves without considerations for time-dependent trends may result in significant errors in sediment yield estimates from the globally-important steep, small watersheds.

On the electrostatic deceleration of argon atoms in high Rydberg states by time-dependent inhomogeneous electric fields

NASA Astrophysics Data System (ADS)

Vliegen, E.; Merkt, F.

2005-06-01

Argon atoms in a pulsed supersonic expansion are prepared in selected Stark components of Rydberg states with effective principal quantum number in the range n* = 15-25. When traversing regions of inhomogeneous electric fields, these atoms get accelerated or decelerated depending on whether the Stark states are low- or high-field seeking states. Using a compact electrode design, which enables the application of highly inhomogeneous and time-dependent electric fields, the Rydberg atoms experience kinetic energy changes of up to 1.2 × 10-21 J (i.e. 60 cm-1 in spectroscopic units) in a single acceleration/deceleration stage of 3 mm length. The resulting differences in the velocities of the low- and high-field seeking states are large enough that the corresponding distributions of times of flight to the Rydberg particle detector are fully separated. As a result, efficient spectral searches of the Rydberg states best suited for acceleration/deceleration experiments are possible. Numerical simulations of the particle trajectories are used to analyse the time-of-flight distributions and to optimize the time dependence of the inhomogeneous electric fields. The decay of the Rydberg states by fluorescence, collisions and transitions induced by black-body radiation takes place on a timescale long enough not to interfere significantly with the deceleration during the first ~5 µs.

Improved tomographic reconstructions using adaptive time-dependent intensity normalization.

PubMed

Titarenko, Valeriy; Titarenko, Sofya; Withers, Philip J; De Carlo, Francesco; Xiao, Xianghui

2010-09-01

The first processing step in synchrotron-based micro-tomography is the normalization of the projection images against the background, also referred to as a white field. Owing to time-dependent variations in illumination and defects in detection sensitivity, the white field is different from the projection background. In this case standard normalization methods introduce ring and wave artefacts into the resulting three-dimensional reconstruction. In this paper the authors propose a new adaptive technique accounting for these variations and allowing one to obtain cleaner normalized data and to suppress ring and wave artefacts. The background is modelled by the product of two time-dependent terms representing the illumination and detection stages. These terms are written as unknown functions, one scaled and shifted along a fixed direction (describing the illumination term) and one translated by an unknown two-dimensional vector (describing the detection term). The proposed method is applied to two sets (a stem Salix variegata and a zebrafish Danio rerio) acquired at the parallel beam of the micro-tomography station 2-BM at the Advanced Photon Source showing significant reductions in both ring and wave artefacts. In principle the method could be used to correct for time-dependent phenomena that affect other tomographic imaging geometries such as cone beam laboratory X-ray computed tomography.

One-Year Efficacy Testing of Enabling Mothers to Prevent Pediatric Obesity Through Web-Based Education and Reciprocal Determinism (EMPOWER) Randomized Control Trial.

PubMed

Knowlden, Adam; Sharma, Manoj

2016-02-01

The purpose of this study was to evaluate the efficacy of the Enabling Mothers to Prevent Pediatric Obesity through Web-Based Education and Reciprocal Determinism (EMPOWER) intervention at 1-year, postintervention follow-up. A mixed between-within subjects design was used to evaluate the trial. Independent variables included a two-level, group assignment: EMPOWER (experimental intervention) based on social cognitive theory (SCT) as well as a knowledge-based intervention Healthy Lifestyles (active control intervention). Dependent variables were evaluated across four levels of time: baseline (Week 0), posttest (Week 4), 1-month follow-up (Week 8), and 1-year follow-up (Week 60). Dependent variables included five maternal-facilitated SCT constructs (environment, emotional coping, expectations, self-control, and self-efficacy) as well as four child behaviors (minutes of child physical activity, cups of fruits and vegetables consumed, 8-ounce glasses of sugar-sweetened beverages consumed, and minutes of screen time). Null hypotheses implied no significant group-by-time interactions for the dependent variables under investigation. A significant group-by-time interaction for child fruit and vegetable consumption was found in the experimental group (p = .012) relative to the control group. At 1 year, results suggested an overall increase of 1.847 cups of fruits and vegetables (95% confidence interval = 1.207-2.498) in the experimental group (p < .001). Analysis suggested changes in the maternal-facilitated home environment accounted for 13.3% of the variance in the change in child fruit and vegetable consumption. Improvements in child physical activity, sugar-free beverage intake, and screen time first detected at 1-month follow-up in both groups were no longer significant at 1-year follow-up. An online family-and-home-based intervention was efficacious for improving child fruit and vegetable consumption. Follow-up booster sessions may assist in maintaining treatment effects. © 2015 Society for Public Health Education.

Exciton interference revealed by energy dependent exciton transfer rate for ring-structured molecular systems

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

Yan, Yun-An, E-mail: yunan@gznc.edu.cn

2016-01-14

The quantum interference is an intrinsic phenomenon in quantum physics for photon and massive quantum particles. In principle, the quantum interference may also occur with quasi-particles, such as the exciton. In this study, we show how the exciton quantum interference can be significant in aggregates through theoretical simulations with hierarchical equations of motion. The systems under investigation are generalized donor-bridge-acceptor model aggregates with the donor consisting of six homogeneous sites assuming the nearest neighbor coupling. For the models with single-path bridge, the exciton transfer time only shows a weak excitation energy dependence. But models with double-path bridge have a newmore » short transfer time scale and the excitation energy dependence of the exciton transfer time assumes clear peak structure which is detectable with today’s nonlinear spectroscopy. This abnormality is attributed to the exciton quantum interference and the condition for a clear observation in experiment is also explored.« less

Rheological Characterization of Unusual DWPF Slurry Samples (U)

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

Koopman, D. C.

2005-09-01

A study was undertaken to identify and clarify examples of unusual rheological behavior in Defense Waste Processing Facility (DWPF) simulant slurry samples. Identification was accomplished by reviewing sludge, Sludge Receipt and Adjustment Tank (SRAT) product, and Slurry Mix Evaporator (SME) product simulant rheological results from the prior year. Clarification of unusual rheological behavior was achieved by developing and implementing new measurement techniques. Development of these new methods is covered in a separate report, WSRC-TR-2004-00334. This report includes a review of recent literature on unusual rheological behavior, followed by a summary of the rheological measurement results obtained on a set ofmore » unusual simulant samples. Shifts in rheological behavior of slurries as the wt. % total solids changed have been observed in numerous systems. The main finding of the experimental work was that the various unusual DWPF simulant slurry samples exhibit some degree of time dependent behavior. When a given shear rate is applied to a sample, the apparent viscosity of the slurry changes with time rather than remaining constant. These unusual simulant samples are more rheologically complex than Newtonian liquids or more simple slurries, neither of which shows significant time dependence. The study concludes that the unusual rheological behavior that has been observed is being caused by time dependent rheological properties in the slurries being measured. Most of the changes are due to the effect of time under shear, but SB3 SME products were also changing properties while stored in sample bottles. The most likely source of this shear-related time dependence for sludge is in the simulant preparation. More than a single source of time dependence was inferred for the simulant SME product slurries based on the range of phenomena observed. Rheological property changes were observed on the time-scale of a single measurement (minutes) as well as on a time scale of hours to weeks. The unusual shape of the slurry flow curves was not an artifact of the rheometric measurement. Adjusting the user-specified parameters in the rheometer measurement jobs can alter the shape of the flow curve of these time dependent samples, but this was not causing the unusual behavior. Variations in the measurement parameters caused the time dependence of a given slurry to manifest at different rates. The premise of the controlled shear rate flow curve measurement is that the dynamic response of the sample to a change in shear rate is nearly instantaneous. When this is the case, the data can be fitted to a time independent rheological equation, such as the Bingham plastic model. In those cases where this does not happen, interpretation of the data is difficult. Fitting time dependent data to time independent rheological equations, such as the Bingham plastic model, is also not appropriate.« less

The pH dependence of cocaine interaction with cardiac sodium channels.

PubMed

Crumb, W J; Clarkson, C W

1995-09-01

Previous in vitro and in vivo studies have provided evidence implicating cocaine block of cardiac sodium channels as a putative mechanism for cocaine-induced arrhythmias and sudden death. Cocaine also has been shown to cause seizures which can result in respiratory and/or metabolic acidosis. In this study we investigated how changes in both internal pH (pHi) and external pH (pHo) over the range of 6.6 to 9.2 modify the sodium channel blocking properties of cocaine in isolated guinea pig ventricular myocytes by using the whole-cell variant of the patch clamp technique. Use-dependent block produced by a train of 1-sec pulses to -20 mV was not affected by changes in pHi, but both the amplitude and time constant for approaching steady-state block were significantly affected by changes in pHo. Characterization of the time course of cocaine binding during a depolarizing pulse indicated that the kinetics of drug interaction with inactivated channels were independent of pHi, but were significantly affected by changes in pHo. The rate of recovery from channel block at a holding potential of -140 mV also was independent of pHi, but strongly dependent on pHo, with the unblocking time constant decreasing exponentially as pHo was increased. The results of this study indicate that cocaine's effect on cardiac sodium channels can be modulated significantly by changes in pHo, and provide further support for previously poorly tested assumptions of the modulated receptor hypothesis.

Optical study on the dependence of breast tissue composition and structure on subject anamnesis

NASA Astrophysics Data System (ADS)

Taroni, Paola; Quarto, Giovanna; Pifferi, Antonio; Abbate, Francesca; Balestreri, Nicola; Menna, Simona; Cassano, Enrico; Cubeddu, Rinaldo

2015-07-01

Time domain multi-wavelength (635 to 1060 nm) optical mammography was performed on 200 subjects to estimate their average breast tissue composition in terms of oxy- and deoxy-hemoglobin, water, lipid and collagen, and structural information, as provided by scattering parameters (amplitude and power). Significant (and often marked) dependence of tissue composition and structure on age, menopausal status, body mass index, and use of oral contraceptives was demonstrated.

Progressive levels of physical dependence to tobacco coincide with changes in the anterior cingulum bundle microstructure.

PubMed

Huang, Wei; DiFranza, Joseph R; Kennedy, David N; Zhang, Nanyin; Ziedonis, Douglas; Ursprung, Sanouri; King, Jean A

2013-01-01

The tobacco withdrawal syndrome indicates the development of neurophysiologic dependence. Clinical evidence indicates that neurophysiologic dependence develops through a set sequence of symptom presentation that can be assessed with a new 3-item survey measure of wanting, craving, and needing tobacco, the Level of Physical Dependence (PD). This study sought to determine if advancing neurophysiologic dependence as measured by the Level of PD correlates with characteristics of white matter structure measured by Fractional Anisotropy (FA). Diffusion-MRI based FA and diffusion tensor imaging probabilistic tractography were used to evaluate 11 smokers and 10 nonsmokers. FA was also examined in relation to two additional measures of dependence severity, the Hooked on Nicotine Checklist (HONC), and the Fagerström Test for Nicotine Dependence (FTND). Among smokers, FA in the left anterior cingulate bundle (ACb) correlated negatively with the Level of PD (r = -0.68, p = 0.02) and HONC scores (r = -0.65, p = 0.03), but the correlation for the FTND did not reach statistical significance (r = -49, p = 0.12). With advancing Levels of PD, the density of streamlines between the ACb and precuneus increased (r = -0.67, p<0.05) and those between the ACb and white matter projecting to the superior-frontal cortex (r = -0.86, p = 0.0006) decreased significantly. The correlations between neural structure and both the clinical Level of PD survey measure and the HONC suggest that the Level of PD and the HONC may reflect the microstructural integrity of white matter, as influenced by tobacco abuse. Given that the Level of PD is measuring a sequence of symptoms of neurophysiologic dependence that develops over time, the correlation between the Level of PD and neural structure suggests that these features might represent neuroplastic changes that develop over time to support the development of neurophysiologic dependence.

Effects of CCR5-delta32 and CCR2-64I alleles on disease progression of perinatally HIV-1-infected children: an international meta-analysis.

PubMed

Ioannidis, John P A; Contopoulos-Ioannidis, Despina G; Rosenberg, Philip S; Goedert, James J; De Rossi, Anita; Espanol, Teresa; Frenkel, Lisa; Mayaux, Marie-Jeanne; Newell, Marie-Louise; Pahwa, Savita G; Rousseau, Christine; Scarlatti, Gabriella; Sei, Shizuko; Sen, Luisa; O'Brien, Thomas R

2003-07-25

Among perinatally infected children, the effects of certain alleles of the CCR5 and CCR2 genes on the rate of disease progression remain unclear. We addressed the effects of CCR5-delta32 and CCR2-64I in an international meta-analysis. Genotype data were contributed from 10 studies with 1317 HIV-1-infected children (7263 person-years of follow-up). Time-to-event analyses were performed stratified by study and racial group. Endpoints included progression to clinical AIDS, death, and death after the diagnosis of clinical AIDS. The time-dependence of the genetic effects was specifically investigated. There was large heterogeneity in the observed rates of disease progression between different cohorts. For progression to clinical AIDS, both CCR5-delta32 and CCR2-64I showed overall non-significant trends for protection [hazard ratios 0.84, 95% confidence interval (CI) 0.58-1.23; and 0.87, 95% CI 0.67-1.14, respectively]. However, analyses of survival showed statistically significant time-dependence. No deaths occurred among CCR5-delta32 carriers in the first 3 years of life, whereas there was no protective effect (hazard ratio 0.95; 95% CI 0.43-2.10) in later years (P=0.01 for the time-dependent model). For CCR2-64I, the hazard ratio for death was 0.69 (95% CI 0.39-1.21) in the first 6 years of life and 2.56 (95% CI 1.26-5.20) in subsequent years (P<0.01 for the time-dependent model). CCR5-delta32 and CCR2-64I offered no clear protection after clinical AIDS had developed. The CCR5-delta32 and CCR2-64I alleles are associated with a decreased risk of death among perinatally infected children, but only for the first years of life.

Distinct effects of protracted withdrawal on affect, craving, selective attention and executive functions among alcohol-dependent patients.

PubMed

Cordovil De Sousa Uva, Mariana; Luminet, Olivier; Cortesi, Marie; Constant, Eric; Derely, Marc; De Timary, Philippe

2010-01-01

The present study examined the effects of protracted alcohol withdrawal on affectivity, craving, selective attention and executive functions (EFs) in alcohol-dependent patients. Selective attention (The D2 Cancellation Test), flexibility (Trail Making Test), inhibition (Stroop Task), decision making (Iowa Gambling Task), craving (Obsessive-Compulsive Drinking Scale) and state affectivity (Positive and Negative Affectivity Schedule) were assessed in alcohol-dependent patients (DSM-IV, n = 35) matched to non-alcohol-dependent participants (n = 22) at the onset (T1: day 1 or 2) and at the end (T2: days 14-18) of protracted withdrawal during rehab. Alcohol-dependent patients' abilities to focus their attention on relevant information, to switch from one pattern to another, to inhibit irrelevant information and to make advantageous choices were lower than those of control participants during both times of a withdrawal cure. No effect of time emerged from analyses for selective attention and EF deficits. Conversely, significant differences between T1 and T2 were observed for craving and affect scores indicating a weakening of alcohol craving and negative affect as well as an improvement of positive affect among patients from onset to the end of cure. Control functions of the Supervisory Attentional System (Norman and Shallice, 1986) were impaired and did not improve during a 3-week withdrawal cure, whereas alcohol craving and negative state affectivity significantly improved in parallel during this period. Implications for understanding the clinical processes of withdrawal are discussed.

Time-Frequency Distribution Analyses of Ku-Band Radar Doppler Echo Signals

NASA Astrophysics Data System (ADS)

Bujaković, Dimitrije; Andrić, Milenko; Bondžulić, Boban; Mitrović, Srđan; Simić, Slobodan

2015-03-01

Real radar echo signals of a pedestrian, vehicle and group of helicopters are analyzed in order to maximize signal energy around central Doppler frequency in time-frequency plane. An optimization, preserving this concentration, is suggested based on three well-known concentration measures. Various window functions and time-frequency distributions were optimization inputs. Conducted experiments on an analytic and three real signals have shown that energy concentration significantly depends on used time-frequency distribution and window function, for all three used criteria.

Computational Issues Associated with Temporally Deforming Geometries Such as Thrust Vectoring Nozzles

NASA Technical Reports Server (NTRS)

Boyalakuntla, Kishore; Soni, Bharat K.; Thornburg, Hugh J.; Yu, Robert

1996-01-01

During the past decade, computational simulation of fluid flow around complex configurations has progressed significantly and many notable successes have been reported, however, unsteady time-dependent solutions are not easily obtainable. The present effort involves unsteady time dependent simulation of temporally deforming geometries. Grid generation for a complex configuration can be a time consuming process and temporally varying geometries necessitate the regeneration of such grids for every time step. Traditional grid generation techniques have been tried and demonstrated to be inadequate to such simulations. Non-Uniform Rational B-splines (NURBS) based techniques provide a compact and accurate representation of the geometry. This definition can be coupled with a distribution mesh for a user defined spacing. The present method greatly reduces cpu requirements for time dependent remeshing, facilitating the simulation of more complex unsteady problems. A thrust vectoring nozzle has been chosen to demonstrate the capability as it is of current interest in the aerospace industry for better maneuverability of fighter aircraft in close combat and in post stall regimes. This current effort is the first step towards multidisciplinary design optimization which involves coupling the aerodynamic heat transfer and structural analysis techniques. Applications include simulation of temporally deforming bodies and aeroelastic problems.

Fecal blood loss caused by two differently microencapsulated acetylsalicylic acid preparations in patients with rheumatoid arthritis. A prospective crossover study.

PubMed

Dirksen, A; Rasmussen, S N; Manthorpe, R

1982-01-01

In an investigator-blind crossover study, fecal blood loss determined by 51Cr-labelled red cells was measured in 17 male patients with rheumatoid arthritis and one with anchylosing spondylitis. In two periods, each of one week's duration and separated by a 3-week wash-out period, the patients received microencapsulated acetylsalicylic acid (ASA) 3 g daily--either iwht time-dependent (Acetard) or with pH-depeendent release (Reumyl). With the exception of one patient, who suffered clinically significant bleeding, both preparations produced only moderate bleeding. The bleeding provoked by ASA with pH-dependent release (median blood loss in ml/day: first period 1.6; last period 2.6) was less than with time-dependent release (first period 1.8; last period 3.5).

Exposure time independent summary statistics for assessment of drug dependent cell line growth inhibition.

PubMed

Falgreen, Steffen; Laursen, Maria Bach; Bødker, Julie Støve; Kjeldsen, Malene Krag; Schmitz, Alexander; Nyegaard, Mette; Johnsen, Hans Erik; Dybkær, Karen; Bøgsted, Martin

2014-06-05

In vitro generated dose-response curves of human cancer cell lines are widely used to develop new therapeutics. The curves are summarised by simplified statistics that ignore the conventionally used dose-response curves' dependency on drug exposure time and growth kinetics. This may lead to suboptimal exploitation of data and biased conclusions on the potential of the drug in question. Therefore we set out to improve the dose-response assessments by eliminating the impact of time dependency. First, a mathematical model for drug induced cell growth inhibition was formulated and used to derive novel dose-response curves and improved summary statistics that are independent of time under the proposed model. Next, a statistical analysis workflow for estimating the improved statistics was suggested consisting of 1) nonlinear regression models for estimation of cell counts and doubling times, 2) isotonic regression for modelling the suggested dose-response curves, and 3) resampling based method for assessing variation of the novel summary statistics. We document that conventionally used summary statistics for dose-response experiments depend on time so that fast growing cell lines compared to slowly growing ones are considered overly sensitive. The adequacy of the mathematical model is tested for doxorubicin and found to fit real data to an acceptable degree. Dose-response data from the NCI60 drug screen were used to illustrate the time dependency and demonstrate an adjustment correcting for it. The applicability of the workflow was illustrated by simulation and application on a doxorubicin growth inhibition screen. The simulations show that under the proposed mathematical model the suggested statistical workflow results in unbiased estimates of the time independent summary statistics. Variance estimates of the novel summary statistics are used to conclude that the doxorubicin screen covers a significant diverse range of responses ensuring it is useful for biological interpretations. Time independent summary statistics may aid the understanding of drugs' action mechanism on tumour cells and potentially renew previous drug sensitivity evaluation studies.

Exposure time independent summary statistics for assessment of drug dependent cell line growth inhibition

PubMed Central

2014-01-01

Background In vitro generated dose-response curves of human cancer cell lines are widely used to develop new therapeutics. The curves are summarised by simplified statistics that ignore the conventionally used dose-response curves’ dependency on drug exposure time and growth kinetics. This may lead to suboptimal exploitation of data and biased conclusions on the potential of the drug in question. Therefore we set out to improve the dose-response assessments by eliminating the impact of time dependency. Results First, a mathematical model for drug induced cell growth inhibition was formulated and used to derive novel dose-response curves and improved summary statistics that are independent of time under the proposed model. Next, a statistical analysis workflow for estimating the improved statistics was suggested consisting of 1) nonlinear regression models for estimation of cell counts and doubling times, 2) isotonic regression for modelling the suggested dose-response curves, and 3) resampling based method for assessing variation of the novel summary statistics. We document that conventionally used summary statistics for dose-response experiments depend on time so that fast growing cell lines compared to slowly growing ones are considered overly sensitive. The adequacy of the mathematical model is tested for doxorubicin and found to fit real data to an acceptable degree. Dose-response data from the NCI60 drug screen were used to illustrate the time dependency and demonstrate an adjustment correcting for it. The applicability of the workflow was illustrated by simulation and application on a doxorubicin growth inhibition screen. The simulations show that under the proposed mathematical model the suggested statistical workflow results in unbiased estimates of the time independent summary statistics. Variance estimates of the novel summary statistics are used to conclude that the doxorubicin screen covers a significant diverse range of responses ensuring it is useful for biological interpretations. Conclusion Time independent summary statistics may aid the understanding of drugs’ action mechanism on tumour cells and potentially renew previous drug sensitivity evaluation studies. PMID:24902483

Investigation of schedules for traffic signal timing optimization.

DOT National Transportation Integrated Search

2005-01-01

Traffic signal optimization is recognized as one of the most cost-effective ways to improve urban mobility; however the extent of the benefits realized could significantly depend on how often traffic signal re-optimization occurs. Using a case study ...

Neurocognitive deficits are associated with unemployment in chronic methamphetamine users

PubMed Central

Weber, Erica; Blackstone, Kaitlin; Iudicello, Jennfer E.; Morgan, Erin E.; Grant, Igor; Moore, David J.; Woods, Steven Paul

2013-01-01

Background Unemployment rates are high among chronic methamphetamine (MA) users and carry a significant economic burden, yet little is known about the neurocognitive and psychiatric predictors of employment in this vulnerable population. Methods The present study examined this issue in 63 participants with recent MA dependence and 47 comparison subjects without histories of MA use disorders. All participants completed a comprehensive neurocognitive, psychiatric and neuromedical evaluation. Individuals with HIV infection, severe neuropsychological or psychiatric conditions that might affect cognition (e.g., seizure disorder, schizophrenia), or a positive Breathalyzer or urine toxicology screen on the day of testing were excluded. Results Consistent with previous research, a logistic regression revealed MA dependence as a significant, independent predictor of full-time unemployment status. Within the MA-dependent sample, greater impairment in global neurocognitive functioning and history of injection drug use emerged as significant independent predictors of unemployment status. The association between worse global cognitive functioning and unemployment was primarily driven by deficits in executive functions, learning, verbal fluency, and working memory. Conclusion These findings indicate that neurocognitive deficits play a significant role in the higher unemployment rates of MA-dependent individuals, and highlight the need for vocational rehabilitation and supported employment programs that assess and bolster cognitive skills in this population. PMID:22560676

The influence of corticosteroid treatment on the outcome of influenza A(H1N1pdm09)-related critical illness.

PubMed

Delaney, Jesse W; Pinto, Ruxandra; Long, Jennifer; Lamontagne, François; Adhikari, Neill K; Kumar, Anand; Marshall, John C; Cook, Deborah J; Jouvet, Philippe; Ferguson, Niall D; Griesdale, Donald; Burry, Lisa D; Burns, Karen E A; Hutchison, Jamie; Mehta, Sangeeta; Menon, Kusum; Fowler, Robert A

2016-03-30

Patients with 2009 pandemic influenza A(H1N1pdm09)-related critical illness were frequently treated with systemic corticosteroids. While observational studies have reported significant corticosteroid-associated mortality after adjusting for baseline differences in patients treated with corticosteroids or not, corticosteroids have remained a common treatment in subsequent influenza outbreaks, including avian influenza A(H7N9). Our objective was to describe the use of corticosteroids in these patients and investigate predictors of steroid prescription and clinical outcomes, adjusting for both baseline and time-dependent factors. In an observational cohort study of adults with H1N1pdm09-related critical illness from 51 Canadian ICUs, we investigated predictors of steroid administration and outcomes of patients who received and those who did not receive corticosteroids. We adjusted for potential baseline confounding using multivariate logistic regression and propensity score analysis and adjusted for potential time-dependent confounding using marginal structural models. Among 607 patients, corticosteroids were administered to 280 patients (46.1%) at a median daily dose of 227 (interquartile range, 154-443) mg of hydrocortisone equivalents for a median of 7.0 (4.0-13.0) days. Compared with patients who did not receive corticosteroids, patients who received corticosteroids had higher hospital crude mortality (25.5% vs 16.4%, p = 0.007) and fewer ventilator-free days at 28 days (12.5 ± 10.7 vs 15.7 ± 10.1, p < 0.001). The odds ratio association between corticosteroid use and hospital mortality decreased from 1.85 (95% confidence interval 1.12-3.04, p = 0.02) with multivariate logistic regression, to 1.71 (1.05-2.78, p = 0.03) after adjustment for propensity score to receive corticosteroids, to 1.52 (0.90-2.58, p = 0.12) after case-matching on propensity score, and to 0.96 (0.28-3.28, p = 0.95) using marginal structural modeling to adjust for time-dependent between-group differences. Corticosteroids were commonly prescribed for H1N1pdm09-related critical illness. Adjusting for only baseline between-group differences suggested a significant increased risk of death associated with corticosteroids. However, after adjusting for time-dependent differences, we found no significant association between corticosteroids and mortality. These findings highlight the challenges and importance in adjusting for baseline and time-dependent confounders when estimating clinical effects of treatments using observational studies.

Allelic association of a dopamine transporter gene polymorphism with antisocial behaviour in heroin-dependent patients.

PubMed

Gerra, Gilberto; Garofano, Luciano; Pellegrini, Caterina; Bosari, Silvano; Zaimovic, Amir; Moi, Gabriele; Avanzini, Paola; Talarico, Enrica; Gardini, Federica; Donnini, Claudia

2005-09-01

Polymorphism of a variable number of tandem repeats (VNTR) in the 3' untranslated region of exon 15 of the SLC6A3 gene, coding for the dopamine transporter (DAT), was analysed to test whether length variation contributes to differences in the individual susceptibility to aggressive - criminal behaviour and liability to heroin dependence. The repeat number of the DAT polymorphism was assessed in 125 healthy subjects and 104 heroin-dependent subjects (including 52 addicted individuals with violent behaviour and criminal records). There was no significant difference in the frequencies of genotypes and alleles between heroin-dependent subjects and control subjects. On the contrary, there was a significant difference between offenders and non-offenders, p = 0.004 and p = 0.002, respectively, among heroin-dependent subjects. No association was found between DAT polymorphism and history of suicide. Buss - Durkee Hostility Inventory (BDHI) mean total scores were significantly higher in heroin addicts than in controls (p < 0.001) and in antisocial - violent heroin addicts in comparison with addicted individuals without antisocial behaviour (p < 0.005). The regression analysis of BDHI subscales, performed to provide an estimate of the magnitude of any potential effect on the risk of aggressiveness associated with the variants in DAT VNTR, showed that the presence of the 9 - 9 genotype significantly increases the risk of irritability and direct aggressiveness more than six and 10 times with respect to the 9 - 10 genotype. Our findings suggest that the 9-repeat allele of the DAT polymorphism confers increased susceptibility to antisocial - violent behaviour and aggressiveness, rather than drug dependence per se in heroin-dependent males.

Epigallocatechin activates haem oxygenase-1 expression via protein kinase Cδ and Nrf2

PubMed Central

Ogborne, Richard M.; Rushworth, Stuart A.; O’Connell, Maria A.

2008-01-01

The Nrf2/anti-oxidant response element (ARE) pathway plays an important role in regulating cellular anti-oxidants, including haem oxygenase-1 (HO-1). Various kinases have been implicated in the pathways leading to Nrf2 activation. Here, we investigated the effect of epigallocatechin (EGC) on ARE-mediated gene expression in human monocytic cells. EGC time and dose dependently increased HO-1 mRNA and protein expression but had minimal effect on expression of other ARE-regulated genes, including NAD(P)H:quinone oxidoreductase 1, glutathione cysteine ligase and ferritin. siRNA knock down of Nrf2 significantly inhibited EGC-induced HO-1 expression. Furthermore, inhibition of PKC by Ro-31-8220 dose dependently decreased EGC-induced HO-1 mRNA expression, whereas MAP kinase and phosphatidylinositol-3-kinase pathway inhibitors had no significant effect. EGC stimulated phosphorylation of PKCαβ and δ in THP-1 cells. PKCδ inhibition significantly decreased EGC-induced HO-1 mRNA expression, whereas PKCα- and β-specific inhibitors had no significant effect. These results demonstrate for the first time that EGC-induced HO-1 expression occurs via PKCδ and Nrf2. PMID:18586007

Effects of length of abstinence on decision-making and craving in methamphetamine abusers.

PubMed

Wang, Guibin; Shi, Jie; Chen, Na; Xu, Lingzhi; Li, Jiali; Li, Peng; Sun, Yan; Lu, Lin

2013-01-01

The majority of drug abusers are incapable of sustaining abstinence over any length of time. Accumulating evidence has linked intense and involuntary craving, Impulsive decision-making and mood disturbances to risk for relapse. However, little is known about temporal changes of these neuropsychological functions in methamphetamine (METH)-dependent individuals. To investigate the effect of length of abstinence on decision-making, craving (baseline and cue-induced), and emotional state in METH-addicted individuals. In this cross-sectional study, 183 adult METH-dependent patients at an addiction rehabilitation center who were abstinent for 6 days (n = 37), 14 days (n = 33), 1 month (n = 31), 3 months (n = 30), 6 months (n = 26), or 1 year (n = 30) and 39 healthy subjects were administered the Iowa Gambling Task (IGT) to assess decision-making performance. Depression, anxiety, and impulsivity were also examined. One hundred thirty-nine METH abusers who were abstinent for the aforementioned times then underwent a cue session, and subjective and physiological measures were assessed. METH dependent individuals who were abstinent for longer periods of time exhibited better decision-making than those who were abstinent for shorter periods of time. And self-reported emotional symptoms improved with abstinence. METH abusers' ratings of craving decreased with the duration of abstinence, while cue-induced craving increased until 3 months of abstinence and decreased at 6 months and 1 year of abstinence. We present time-dependent alterations in decision-making, emotional state, and the incubation of cue-induced craving in METH-dependent individuals, which might have significant clinical implications for the prevention of relapse.

Competitive STDP Learning of Overlapping Spatial Patterns.

PubMed

Krunglevicius, Dalius

2015-08-01

Spike-timing-dependent plasticity (STDP) is a set of Hebbian learning rules firmly based on biological evidence. It has been demonstrated that one of the STDP learning rules is suited for learning spatiotemporal patterns. When multiple neurons are organized in a simple competitive spiking neural network, this network is capable of learning multiple distinct patterns. If patterns overlap significantly (i.e., patterns are mutually inclusive), however, competition would not preclude trained neuron's responding to a new pattern and adjusting synaptic weights accordingly. This letter presents a simple neural network that combines vertical inhibition and Euclidean distance-dependent synaptic strength factor. This approach helps to solve the problem of pattern size-dependent parameter optimality and significantly reduces the probability of a neuron's forgetting an already learned pattern. For demonstration purposes, the network was trained for the first ten letters of the Braille alphabet.

Characterization of binding of N'-nitrosonornicotine to protein

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

Hughes, M.F.

1986-01-01

The NADPH-dependent activation of the carcinogenic nitrosamine, N'-nitrosonornicotine (NNN) to a reactive intermediate which binds covalently to protein was assessed using male Sprague-Dawley rat liver and lung microsomes. The NADPH-dependent covalent binding of (/sup 14/C)NNN to liver and lung microsomes was linear with time up to 90 and 45 min, respectively and was also linear with protein concentrations up to 3.0 and 2.0 mg/ml, respectively. The apparent K/sub m/ and V/sub max/ of the NADPH-dependent binding to liver microsomes were determined from the initial velocities. Addition of the thiols glutathione, cystein, N-acetylcysteine or 2-mercapthoethanol significantly decreased the non-NADPH-dependent binding tomore » liver microsomal protein, but did not affect the NADPH-dependent binding. Glutathione was required in order to observe any NADPH-dependent binding to lung microsomal protein. In lung microsomes, SKF-525A significantly decreased the NADPH-dependent binding by 79%. Replacement of an air atmosphere with N/sub 2/ or CO:O/sub 2/ (8:2) significantly decreased the NADPH-dependent binding of (/sup 14/C)NNN to liver microsomal protein by 40% or 27% respectively. Extensive covalent binding of (/sup 14/C)NNN to liver and muscle microsomal protein occurred in the absence of an NADPH-generating system, in the presence of 50% methanol and also to bovine serum albumin, indicating a nonenzymatic reaction. These data indicate that cytochrome P-450 is at least in part responsible for the metabolic activation of the carcinogen NNN, but also suggest additional mechanisms of activation.« less

Stress dependence of permeability of intact and fractured shale cores.

NASA Astrophysics Data System (ADS)

van Noort, Reinier; Yarushina, Viktoriya

2016-04-01

Whether a shale acts as a caprock, source rock, or reservoir, understanding fluid flow through shale is of major importance for understanding fluid flow in geological systems. Because of the low permeability of shale, flow is thought to be largely confined to fractures and similar features. In fracking operations, fractures are induced specifically to allow for hydrocarbon exploration. We have constructed an experimental setup to measure core permeabilities, using constant flow or a transient pulse. In this setup, we have measured the permeability of intact and fractured shale core samples, using either water or supercritical CO2 as the transporting fluid. Our measurements show decreasing permeability with increasing confining pressure, mainly due to time-dependent creep. Furthermore, our measurements show that for a simple splitting fracture, time-dependent creep will also eliminate any significant effect of this fracture on permeability. This effect of confinement on fracture permeability can have important implications regarding the effects of fracturing on shale permeability, and hence for operations depending on that.

Modeling carbon production and transport during ELMs in DIII-D

NASA Astrophysics Data System (ADS)

Hogan, J.; Wade, M.; Coster, D.; Lasnier, C.

2004-11-01

Large-scale Type I ELM events could provide a significant C source in ITER, and C production rates depend on incident D flux density and surface temperature, quantities which can vary significantly during an ELM event. Recent progress on DIII-D has improved opportunities for code comparison. Fast time-scale measurements of divertor CIII evolution [1] and fast edge CER measurements of C profile evolution during low-density DIII-D LSN ELMy H-modes (type I) [2] have been modeled using the solps5.0/Eirene99 coupled edge code and time dependent thermal analysis codes. An ELM model based on characteristics of MHD peeling-ballooning modes reproduces the pedestal evolution. Qualitative agreement for the CIII evolution during an ELM event is found using the Roth et al annealing model for chemical sputtering and the sensitivity to other models is described. Significant ELM-to-ELM variations in observed maximum divertor target IR temperature during nominally identical ELMs are investigated with models for C emission from micron-scale dust particles. [1] M Groth, M Fenstermacher et al J Nucl Mater 2003, [2] M Wade, K Burrell et al PSI-16

Significant enhancement of yellow-green light emission of ZnO nanorod arrays using Ag island films

NASA Astrophysics Data System (ADS)

Lin, Chin-An; Tsai, Dung-Sheng; Chen, Cheng-Ying; He-Hau, Jr.

2011-03-01

Surface plasmon (SP) mediated emission from ZnO nanorod arrays (NRAs)/Ag/Si structures has been investigated. The ratio of visible emission to UV emission can be increased by over 30 times via coupling with SP without deterioration of the crystal quality. The fact that the effect of SP crucially depends on the size of Ag island films provides the feasibility to significantly enhance the yellow-green emission of the ZnO nanostructures without sacrificing the crystallinity of ZnO.Surface plasmon (SP) mediated emission from ZnO nanorod arrays (NRAs)/Ag/Si structures has been investigated. The ratio of visible emission to UV emission can be increased by over 30 times via coupling with SP without deterioration of the crystal quality. The fact that the effect of SP crucially depends on the size of Ag island films provides the feasibility to significantly enhance the yellow-green emission of the ZnO nanostructures without sacrificing the crystallinity of ZnO. Electronic supplementary information (ESI) available. See DOI: 10.1039/c0nr00732c

Evaluation of protocol change in burn-care management using the Cox proportional hazards model with time-dependent covariates.

PubMed

Ichida, J M; Wassell, J T; Keller, M D; Ayers, L W

1993-02-01

Survival analysis methods are valuable for detecting intervention effects because detailed information from patient records and sensitive outcome measures are used. The burn unit at a large university hospital replaced routine bathing with total body bathing using chlorhexidine gluconate for antimicrobial effect. A Cox proportional hazards model was used to analyse time from admission until either infection with Staphylococcus aureus or discharge for 155 patients, controlling for burn severity and two time-dependent covariates: days until first wound excision and days until first administration of prophylactic antibiotics. The risk of infection was 55 per cent higher in the historical control group, although not statistically significant. There was also some indication that early wound excision may be important as an infection-control measure for burn patients.

Times of Maximum Light: The Passband Dependence

NASA Astrophysics Data System (ADS)

Joner, M. D.; Laney, C. D.

2004-05-01

We present UBVRIJHK light curves for the dwarf Cepheid variable star AD Canis Minoris. These data are part of a larger project to determine absolute magnitudes for this class of stars. Our figures clearly show changes in the times of maximum light, the amplitude, and the light curve morphology that are dependent on the passband used in the observation. Note that when data from a variety of passbands are used in studies that require a period analysis or that search for small changes in the pulsational period, it is easy to introduce significant systematic errors into the results. We thank the Brigham Young University Department of Physics and Astronmy for continued support of our research. We also acknowledge the South African Astronomical Observatory for time granted to this project.

A comparison of Solar Mesosphere Explorer and Stratosphere Aerosol and Gas Experiment II ozone densities near the stratopause

NASA Technical Reports Server (NTRS)

Rusch, D. W.; Clancy, R. T.; Mccormick, M. P.; Zawodny, J. M.

1990-01-01

Ozone measurements made by the SME UV Spectrometer and the Stratosphere Aerosol and Gas Experiment II (SAGE II) spectometer are compared at 1.0 mbar for the time period from October 1984 to December 1986, using a model of the diurnal variation of ozone to correct for the difference in local times of the two measurements. The absolute values of the ozone mixing ratio measured by the two spectrometers were found to agree to better than 5 percent, with no significant divergence between the instruments. It is concluded that, since the SAGE II data are not dependent on the absolute calibration of the instrument, these data can be used as time-dependent 'ground truth' measurements for comparisons with other instruments.

Investigations on blood coagulation in the green iguana (Iguana iguana).

PubMed

Kubalek, S; Mischke, R; Fehr, M

2002-05-01

The prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time, kaolin clotting time (KCT), dilute Russell's viper venom time (DRVVT) and reptilase time, as well as five different plasma fibrinogen assays [gravimetry, Jacobsson method (extinction at 280 nm), Millar method (heat precipitation), kinetic turbidometry, Clauss method] and resonance thrombography were performed in 26 clinically healthy green iguanas. All assays were carried out in comparison with pooled normal canine plasma. In iguana plasma, the PT [median (x0.50) = 453-831 s, dependent on the reagent], APTT (x0.50 = 170-242 s, dependent on the reagent), thrombin time (x0.50 = 118 - > 1000 s, dependent on thrombin activity), KCT (x0.50 = 274 s), DRVVT (x0.50 = 349 s) and reptilase time (all samples > 1000 s) were widely scattered at the limit of measurability. Only fibrinogen concentrations measured using the Jacobsson method (x0.50 = 4.40 g/l) correlated well (r = 0.91) with gravimetry (x0.50 = 4.22 g/l). The results of this study indicate a limited suitability and a confined diagnostic significance of the selected methods in the green iguana. This may be caused by the species specificity of certain components of the reagents used, as well as a less optimal test system, i.e. relationship of test reagent to clotting factor concentrations in iguana plasma.

Where do we stand after twenty years of dynamic triggering studies? (Invited)

NASA Astrophysics Data System (ADS)

Prejean, S. G.; Hill, D. P.

2013-12-01

In the past two decades, remote dynamic triggering of earthquakes by other earthquakes has been explored in a variety of physical environments with a wide array of observation and modeling techniques. These studies have significantly refined our understanding of the state of the crust and the physical conditions controlling earthquake nucleation. Despite an ever growing database of dynamic triggering observations, significant uncertainties remain and vigorous debate in almost all aspects of the science continues. For example, although dynamic earthquake triggering can occur with peak dynamic stresses as small as 1 kPa, triggering thresholds and their dependence on local stress state, hydrological environment, and frictional properties of faults are not well understood. Some studies find a simple threshold based on the peak amplitude of shaking while others find dependencies on frequency, recharge time, and other parameters. Considerable debate remains over the range of physical processes responsible for dynamic triggering, and the wide variation in dynamic triggering responses and time scales suggests triggering by multiple physical processes. Although Coulomb shear failure with various friction laws can often explain dynamic triggering, particularly instantaneous triggering, delayed dynamic triggering may be dependent on fluid transport and other slowly evolving aseismic processes. Although our understanding of the global distribution of dynamic triggering has improved, it is far from complete due to spatially uneven monitoring. A major challenge involves establishing statistical significance of potentially triggered earthquakes, particularly if they are isolated events or time-delayed with respect to triggering stresses. Here we highlight these challenges and opportunities with existing data. We focus on environmental dependence of dynamic triggering by large remote earthquakes particularly in volcanic and geothermal systems, as these systems often have high rates of background seismicity. In many volcanic and geothermal systems, such as the Geysers in Northern California, dynamic triggering of micro-earthquakes is frequent and predictable. In contrast, most active and even erupting volcanoes in Alaska (with the exception of the Katmai Volcanic Cluster) do not experience dynamic triggering. We explore why.

Viscoelastic Properties of Collagen-Adhesive Composites under Water Saturated and Dry Conditions

PubMed Central

Singh, Viraj; Misra, Anil; Parthasarathy, Ranganathan; Ye, Qiang; Spencer, Paulette

2014-01-01

To investigate the time and rate dependent mechanical properties of collagen-adhesive composites, creep and monotonic experiments are performed under dry and wet conditions. The composites are prepared by infiltration of dentin adhesive into a demineralized bovine dentin. Experimental results show that for small stress level under dry conditions, both the composite and neat adhesive have similar behavior. On the other hand, in wet conditions, the composites are significantly soft and weak compared to the neat adhesives. The behavior in the wet condition is found to be affected by the hydrophilicity of both the adhesive and collagen. Since the adhesive-collagen composites area part of the complex construct that forms the adhesive-dentin interface, their presence will affect the overall performance of the restoration. We find that Kelvin-Voigt model with at least 4-elements is required to fit the creep compliance data, indicating that the adhesive-collagen composites are complex polymers with several characteristics time-scales whose mechanical behavior will be significantly affected by loading rates and frequencies. Such mechanical properties have not been investigated widely for these types of materials. The derived model provides an additional advantage that it can be exploited to extract other viscoelastic properties which are, generally, time consuming to obtain experimentally. The calibrated model is utilized to obtain stress relaxation function, frequency-dependent storage and loss modulus, and rate dependent elastic modulus. PMID:24753362

How does the plasmonic enhancement of molecular absorption depend on the energy gap between molecular excitation and plasmon modes: a mixed TDDFT/FDTD investigation.

PubMed

Sun, Jin; Li, Guang; Liang, WanZhen

2015-07-14

A real-time time-dependent density functional theory coupled with the classical electrodynamics finite difference time domain technique is employed to systematically investigate the optical properties of hybrid systems composed of silver nanoparticles (NPs) and organic adsorbates. The results demonstrate that the molecular absorption spectra throughout the whole energy range can be enhanced by the surface plasmon resonance of Ag NPs; however, the absorption enhancement ratio (AER) for each absorption band differs significantly from the others, leading to the quite different spectral profiles of the hybrid complexes in contrast to those of isolated molecules or sole NPs. Detailed investigations reveal that the AER is sensitive to the energy gap between the molecular excitation and plasmon modes. As anticipated, two separate absorption bands, corresponding to the isolated molecules and sole NPs, have been observed at a large energy gap. When the energy gap approaches zero, the molecular excitation strongly couples with the plasmon mode to form the hybrid exciton band, which possesses the significantly enhanced absorption intensity, a red-shifted peak position, a surprising strongly asymmetric shape of the absorption band, and the nonlinear Fano effect. Furthermore, the dependence of surface localized fields and the scattering response functions (SRFs) on the geometrical parameters of NPs, the NP-molecule separation distance, and the external-field polarizations has also been depicted.

[Trigger factor dependent refolding of bacterial luciferases in Escherichia coli cells: kinetics, efficiency and effect of the bichaperone system, DnaKJE-ClpB].

PubMed

Mel'kina, O E; Gorianin, I I; Manukhov, I V; Zavil'gel'skiĭ, G B

2013-01-01

Here were determined the basic parameters of the Tigger Factor (TF) -dependent refolding of thermal inactivated bacterial luciferases. The TF-dependent refolding is less efficient and requires more time than DnaKJE-dependent refolding. The increase in the intracellular concentration of TF leads to an apparent decrease in the level of the thermal inactivated bacterial luciferase refolding. For thermolabile luciferases, the level of TF-dependent refolding is significantly higher, than for thermostable luciferases: 30-40%--for the thermolabile Aliivibrio fischeri and Photobacterium leiognathi luciferases, and 10 and 0.5% for the thermostable Vibrio harveyi and Photorhabdus luminescens luciferases, respectively. The negative effect of the ClpB protein on the TF-dependent refolding was shown: in Escherichia coli clpB::kan TF-dependent refolding is more efficient than in the E. coli clpB+.

Psychopathological symptoms, defense mechanisms and time perspectives among subjects with alcohol dependence (AD) presenting different patterns of coping with stress.

PubMed

Iwanicka, Katarzyna; Gerhant, Aneta; Olajossy, Marcin

2017-01-01

The problem of coping with stress is an important one in the context of development and persistence of alcohol dependence. In the literature to date very little attention has been paid to coping patterns construed as a configuration of specific coping styles, particularly as regards the functioning of addicted individuals. The aim of the study was to verify whether individuals with alcohol dependence characterized by different coping patterns differ with respect to the severity of psychopathological symptoms, defense mechanisms and time perspectives. Participants were given a battery of psychological tests-Coping Inventory for Stresfull Situations (CISS), Defense Style Questionnaire (DSQ 40), Syndrom Checklist (SCL-90) and Short Zimbardo Time Perspective Inventory (SZPTI-PL). The sample comprised 112 individuals with alcohol dependence, aged 20 to 63 years old, the average age was 37.86; 78 percent were men. There were identified three sub-groups of individuals characterized by a distinctive patterns of coping with stress -"emotional-avoidant", "task oriented" and a "mixed one". Individuals with the predominant emotional-avoidant coping pattern are characterized by significantly higher severity of psychopathological symptoms, less mature defense mechanisms and past time perspectives. Subjects reliant on task-oriented coping pattern were characterized by the highest level of adaptation and the most constructive way of functioning in the face of difficulties. It is worth regarding the examination of patterns of coping as an indispensable element of collecting medical history from alcohol dependent individuals.

Detection of regional infrasound signals using array data: Testing, tuning, and physical interpretation

DOE PAGES

Park, Junghyun; Stump, Brian W.; Hayward, Chris; ...

2016-07-14

This work quantifies the physical characteristics of infrasound signal and noise, assesses their temporal variations, and determines the degree to which these effects can be predicted by time-varying atmospheric models to estimate array and network performance. An automated detector that accounts for both correlated and uncorrelated noise is applied to infrasound data from three seismo-acoustic arrays in South Korea (BRDAR, CHNAR, and KSGAR), cooperatively operated by Korea Institute of Geoscience and Mineral Resources (KIGAM) and Southern Methodist University (SMU). Arrays located on an island and near the coast have higher noise power, consistent with both higher wind speeds and seasonablymore » variable ocean wave contributions. On the basis of the adaptive F-detector quantification of time variable environmental effects, the time-dependent scaling variable is shown to be dependent on both weather conditions and local site effects. Significant seasonal variations in infrasound detections including daily time of occurrence, detection numbers, and phase velocity/azimuth estimates are documented. These time-dependent effects are strongly correlated with atmospheric winds and temperatures and are predicted by available atmospheric specifications. As a result, this suggests that commonly available atmospheric specifications can be used to predict both station and network detection performance, and an appropriate forward model improves location capabilities as a function of time.« less

Detection of regional infrasound signals using array data: Testing, tuning, and physical interpretation.

PubMed

Park, Junghyun; Stump, Brian W; Hayward, Chris; Arrowsmith, Stephen J; Che, Il-Young; Drob, Douglas P

2016-07-01

This work quantifies the physical characteristics of infrasound signal and noise, assesses their temporal variations, and determines the degree to which these effects can be predicted by time-varying atmospheric models to estimate array and network performance. An automated detector that accounts for both correlated and uncorrelated noise is applied to infrasound data from three seismo-acoustic arrays in South Korea (BRDAR, CHNAR, and KSGAR), cooperatively operated by Korea Institute of Geoscience and Mineral Resources (KIGAM) and Southern Methodist University (SMU). Arrays located on an island and near the coast have higher noise power, consistent with both higher wind speeds and seasonably variable ocean wave contributions. On the basis of the adaptive F-detector quantification of time variable environmental effects, the time-dependent scaling variable is shown to be dependent on both weather conditions and local site effects. Significant seasonal variations in infrasound detections including daily time of occurrence, detection numbers, and phase velocity/azimuth estimates are documented. These time-dependent effects are strongly correlated with atmospheric winds and temperatures and are predicted by available atmospheric specifications. This suggests that commonly available atmospheric specifications can be used to predict both station and network detection performance, and an appropriate forward model improves location capabilities as a function of time.

Characterization of viscoelastic response and damping of composite materials used in flywheel rotors

NASA Astrophysics Data System (ADS)

Chen, Jianmin

The long-term goal for spacecraft flywheel systems with higher energy density at the system level requires new and innovative composite material concepts. Multi-Direction Composite (MDC) offers significant advantages over traditional filament-wound and multi-ring press-fit filament-wound wheels in providing higher energy density (i.e., less mass), better crack resistance, and enhanced safety. However there is a lack of systematic characterization for dynamic properties of MDC composite materials. In order to improve the flywheel materials reliability, durability and life time, it is very important to evaluate the time dependent aging effects and damping properties of MDC material, which are significant dynamic parameter for vibration and sound control, fatigue endurance, and impact resistance. The physical aging effects are quantified based on a set of creep curves measured at different aging time or different aging temperature. One parameter (tau) curve fit was proposed to represent the relationship of aging time and aging temperature between different master curves. The long term mechanical behavior was predicted by obtained master curves. The time and temperature shift factors of matrix were obtained from creep curves and the aging time shift rate were calculated. The aging effects on composite are obtained from experiments and compared with prediction. The mechanical quasi-behavior of MDC composite was analyzed. The correspondence principle was used to relate quasi-static elastic properties of composite materials to time-dependent properties of its constituent materials (i.e., fiber and matrix). The Prony series combined with the multi-data fitting method was applied to inverse Laplace transform and to calculate the time dependent stiffness matrix effectively. Accelerated time-dependent deformation of two flywheel rim designs were studied for a period equivalent to 31 years and are compared with hoop reinforcement only composite. Damping of pure resin and T700/epoxy composite lamina and laminate in longitudinal and transverse directions were investigated experimentally and analytically. The effect of aging on damping was also studied by placing samples at 60°C in an oven for extended periods. Damping master curves versus frequency were constructed from individual curves at different temperatures based on the Arrhenius equation. The damping response of the composite lamina was used to predict the response of laminate composites. Analytical results give close numerical values to experimental results from damping of cantilever beam laminated composite samples.

The salivary β-HEX A% index as an excellent marker of periodontitis in smoking alcohol-dependent persons.

PubMed

Waszkiewicz, Napoleon; Zalewska-Szajda, Beata; Chojnowska, Sylwia; Szajda, Sławomir Dariusz; Zalewska, Anna; Konarzewska, Beata; Szulc, Agata; Wojtulewska-Supron, Aleksandra; Kępka, Alina; Knaś, Małgorzata; Ładny, Jerzy Robert; Milewski, Robert; Zwierz, Krzysztof

2013-01-01

Severe periodontitis leading to tooth loss is found in 5-15% of most populations worldwide. The applicability of salivary β -hexosaminidase (β-HEX A%, percentage of β-HEX A isoenzyme to total β-HEX) and β-HEX B% (β-HEX B/β-HEX) indexes was investigated as a possible marker of periodontitis. Thirty three alcohol-dependent smokers (AS) and 32 healthy controls (C) were enrolled in the study. The activity of β-HEX was measured spectrophotometrically. β-HEX A% was significantly higher and β-HEX B% was lower in AS than in C group. We found a significant correlation between β-HEX A% and gingival index (GI) and an inverse correlation between β-HEX A% and salivary flow (SF), in all groups. Salivary β-HEX A% index in smoking alcoholics at 0.23 had excellent sensitivity (96%) and specificity (91%); the AUC for β-HEX A% was high (0.937). There were no correlations between amount/duration-time of alcohol drinking/smoking and β-HEX A% or β-HEX B%. We found significant correlations between the time period of denture wearing and GI, papilla bleeding index (PBI), and decayed missing filled teeth index (DMFT) and between GI and the amount of smoked cigarettes per day. Bad periodontal state was most likely due to the nicotine dependence. Salivary β-HEX A% is a promising excellent marker for the diagnosis of periodontitis.

Effect of ultrasonic treatment on reduction of Esherichia coli ATCC 25922 and egg quality parameters in experimentally contaminated hens' shell eggs.

PubMed

Sert, Durmus; Aygun, Ali; Torlak, Emrah; Mercan, Emin

2013-09-01

In this study, hen eggs which were experimentally contaminated with Esherichia coli ATCC 25922 were used. Contaminated eggs were washed statically (S5 to S30; 0 kHz) and by ultrasonic waves (U5 to U30; 35 kHz) for given applications of time (5, 15 and 30 min), then the eggs were stored at 22°C for 14 days. Depending on the time of ultrasonic application, a significant increase in egg shell strength (P < 0.01) was recorded. The highest value of the Haugh unit (67.93, 1 day) was observed on the eggs which were washed by ultrasonic waves. Yolk width values of ultrasonic washed eggs diminished. E. coli was completely removed by 30 min of ultrasonic application. During storage E. coli growth was not detected on the eggs which were washed by ultrasonic waves except the eggs in U5 group (2.04 log CFU eggshell⁻¹) on the first day of storage. Depending on the time of ultrasonic application a significant increase in egg quality parameters (shell strength, albumen height, Haugh units, and yolk height) were observed. The application of ultrasound led to a significant reduction in E. coli numbers on egg shells. © 2013 Society of Chemical Industry.

The effect of physical activity on sleep quality, well-being, and affect in academic stress periods.

PubMed

Wunsch, Kathrin; Kasten, Nadine; Fuchs, Reinhard

2017-01-01

The stress-buffering hypothesis postulates that physical activity and exercise can buffer the negative effects of (academic) stress on health. It still remains an open question whether students, who regularly engage in physical activity and exercise within their academic examination period, can successfully diminish these negative effects. Sixty-four subjects participated in this study and completed a total of five surveys, with T1 at the end of the semester break (baseline) and T2-T5 being presented every Friday in the last 4 weeks of the semester (examination period). They were asked to answer questions about their activity level, sleep quality, well-being and affect. Hierarchical linear models showed significant dependencies on time for all dependent measures. The expansion of the model for exercise also showed significant main effects of this predictor on well-being and positive affect (PA) and negative affect. Moreover, significant interactions with time for sleep quality and PA were found. Results suggest that physical activity and exercise in the academic examination period may be able to buffer the negative effects of stress on health-related outcomes. Therefore, activity levels should be maintained in times of high stress to prevent negative effects on sleep, well-being and affect in students.

The Influence of Pituitary Size on Outcome After Transsphenoidal Hypophysectomy in a Large Cohort of Dogs with Pituitary-Dependent Hypercortisolism.

PubMed

van Rijn, S J; Galac, S; Tryfonidou, M A; Hesselink, J W; Penning, L C; Kooistra, H S; Meij, B P

2016-07-01

Transsphenoidal hypophysectomy is one of the treatment strategies in the comprehensive management of dogs with pituitary-dependent hypercortisolism (PDH). To describe the influence of pituitary size at time of pituitary gland surgery on long-term outcome. Three-hundred-and-six dogs with PDH. Survival and disease-free fractions were analyzed and related to pituitary size; dogs with and without recurrence were compared. Four weeks after surgery, 91% of dogs were alive and remission was confirmed in 92% of these dogs. The median survival time was 781 days, median disease-free interval was 951 days. Over time, 27% of dogs developed recurrence of hypercortisolism after a median period of 555 days. Dogs with recurrence had significantly higher pituitary height/brain area (P/B) ratio and pre-operative basal urinary corticoid-to-creatinine ratio (UCCR) than dogs without recurrence. Survival time and disease-free interval of dogs with enlarged pituitary glands was significantly shorter than that of dogs with a non-enlarged pituitary gland. Pituitary size at the time of surgery significantly increased over the 20-year period. Although larger tumors have a less favorable prognosis, outcome in larger tumors improved over time. Transsphenoidal hypophysectomy is an effective treatment for PDH in dogs, with an acceptable long-term outcome. Survival time and disease-free fractions are correlated negatively with pituitary gland size, making the P/B ratio an important pre-operative prognosticator. However, with increasing experience, and for large tumors, pituitary gland surgery remains an option to control the pituitary mass and hypercortisolism. Copyright © 2016 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

Necroptosis contributes to methamphetamine-induced cytotoxicity in rat cortical neurons.

PubMed

Xiong, Kun; Liao, Huidan; Long, Lingling; Ding, Yanjun; Huang, Jufang; Yan, Jie

2016-09-01

Necroptosis, a programmed necrosis, is involved in various types of neurodegenerative diseases. In this study, we investigated whether necroptosis contributed to neuronal damage in a methamphetamine injury model. Primary cultures of embryonic cortical neurons from Sprague-Dawley rats were subjected to different doses of methamphetamine with/without pre-treatment with a specific necroptosis inhibitor, Necrostatin-1. Necrosis was assessed by determining lactate dehydrogenase release and by Annexin V/propidium iodide double staining, while the neuronal ultra-structure was examined by electron microscopy. Tumor necrosis factor-α protein levels were determined by enzyme-linked immunosorbent assay. At early stages (12h) of post-treatment with methamphetamine, significant necrosis occurred and the viability of neurons decreased in a dose- and time-dependent manner in this model of acute neuronal injury. Pretreatment with Necrostatin-1 led to significant neuronal preservation compared with the methamphetamine-treated groups. Furthermore, tumor necrosis factor-α expression increased in a dose-dependent manner following methamphetamine exposure. Methamphetamine induced necrosis in rat cortical neurons in vitro, both time and dose dependently, and necroptosis may be an important newly identified mode of cortical neuronal death caused by single high-dose methamphetamine administration. Copyright © 2016 Elsevier B.V. All rights reserved.

Charge and energy dependence of the residence time of cosmic ray nuclei below 15 GeV/nucleon

NASA Technical Reports Server (NTRS)

Soutoul, A.; Engelmann, J. J.; Ferrando, P.; Koch-Miramond, L.; Masse, P.; Webber, W. R.

1985-01-01

The relative abundance of nuclear species measured in cosmic rays at Earth has often been interpreted with the simple leaky box model. For this model to be consistent an essential requirement is that the escape length does not depend on the nuclear species. The discrepancy between escape length values derived from iron secondaries and from the B/C ratio was identified by Garcia-Munoz and his co-workers using a large amount of experimental data. Ormes and Protheroe found a similar trend in the HEAO data although they questioned its significance against uncertainties. They also showed that the change in the B/C ratio values implies a decrease of the residence time of cosmic rays at low energies in conflict with the diffusive convective picture. These conclusions crucially depend on the partial cross section values and their uncertainties. Recently new accurate cross sections of key importance for propagation calculations have been measured. Their statistical uncertainties are often better than 4% and their values significantly different from those previously accepted. Here, these new cross sections are used to compare the observed B/C+O and (Sc to Cr)/Fe ratio to those predicted with the simple leaky box model.

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

Miyasaka, Hiromasa; Harrison, Fiona A.; Fürst, Felix

The Nuclear Spectroscopic Telescope Array hard X-ray telescope observed the transient Be/X-ray binary GS 0834–430 during its 2012 outburst—the first active state of this system observed in the past 19 yr. We performed timing and spectral analysis and measured the X-ray spectrum between 3-79 keV with high statistical significance. We find the phase-averaged spectrum to be consistent with that observed in many other magnetized, accreting pulsars. We fail to detect cyclotron resonance scattering features that would allow us to constrain the pulsar's magnetic field in either phase-averaged or phase-resolved spectra. Timing analysis shows a clearly detected pulse period of ∼12.29more » s in all energy bands. The pulse profiles show a strong, energy-dependent hard phase lag of up to 0.3 cycles in phase, or about 4 s. Such dramatic energy-dependent lags in the pulse profile have never before been reported in high-mass X-ray binary pulsars. Previously reported lags have been significantly smaller in phase and restricted to low energies (E < 10 keV). We investigate the possible mechanisms that might produce this energy-dependent pulse phase shift. We find the most likely explanation for this effect is a complex beam geometry.« less

Is EG 50 a White or Strange Dwarf?

NASA Astrophysics Data System (ADS)

Hajyan, G. S.; Vartanyan, Yu. L.

2017-12-01

The time dependences of the luminosity of a white dwarf and four strange dwarfs with masses of 0.5 M (the mass of the white dwarf EG 50 with a surface temperature of 2.1·104 K) are determined taking neutrino energy losses into account. It was assumed that these configurations radiate only at the expense of thermal energy reserves. It is shown that the sources of thermal energy owing to nonequilibrium b-processes and the phenomenon of crystallization of electron-nuclear matter are insignificant in determining the cooling time of white and strange dwarfs with masses of 0.5 M⨀. It is shown that in this approximation the time dependences of the luminosity of white and strange dwarfs with masses of 0.5 M⨀ differ significantly only for surface temperatures TR≥7·104 K, so it is impossible to determine whether EG 50 is a white or strange dwarf based on the cooling time.

Clove oil as an anaesthetic for adult sockeye salmon: Field trials

USGS Publications Warehouse

Woody, C.A.; Nelson, Jack L.; Ramstad, K.

2002-01-01

Wild migrating sockeye salmon Oncorhynchus nerka exposed to 20, 50 and 80 mg 1-1 of clove oil could be handled within 3 min, recovered within 10 min, and survived 15 min exposure trials. Fish tested at 110 mg 1-1 did not recover from 15 min exposure trials. Response curves developed for induction and recovery time considered the following predictors: clove oil concentration, sex, fish length and depth. A significant positive dependence was observed between induction time and fish length for 20, 50 and 80 mg 1-1 test concentrations; no dependence was observed between induction time and length at 110 and 140 mg 1-1. Recovery time differed as a function of clove oil concentration, but not fish size. A concentration of 50 mg 1-1 is recommended for anaesthetizing sockeye salmon ranging in length from 400 to 550 mm at water temperatures averaging 9-10??C.

Direct comparison of two different mesalamine formulations for the induction of remission in patients with ulcerative colitis: A double-blind, randomized study

PubMed Central

Ito, Hiroaki; Iida, Mitsuo; Matsumoto, Takayuki; Suzuki, Yasuo; Sasaki, Hidetaka; Yoshida, Toyomitsu; Takano, Yuichi; Hibi, Toshifumi

2010-01-01

Background: Mesalamine is the first-line drug for the treatment of ulcerative colitis (UC). We directly compared the efficacy and safety of two mesalamine formulations for the induction of remission in patients with UC. Methods: In a multicenter, double-blind, randomized study, 229 patients with mild-to-moderate active UC were assigned to 4 groups: 66 and 65 received a pH-dependent release formulation of 2.4 g/day (pH-2.4 g) or 3.6 g/day (pH-3.6 g), respectively; 65 received a time-dependent release formulation of 2.25 g/day (Time-2.25 g), and 33 received placebo (Placebo). The drugs were administered three times daily for eight weeks. The primary endpoint was a decrease in the UC disease activity index (UC-DAI). Results: In the full analysis set (n = 225) the decrease in UC-DAI in each group was 1.5 in pH-2.4 g, 2.9 in pH-3.6 g, 1.3 in Time-2.25 g and 0.3 in Placebo, respectively. These results demonstrate the superiority of pH-3.6 g over Time-2.25 g (P = 0.003) and the noninferiority of pH-2.4 g to Time-2.25 g. Among the patients with proctitis-type UC, a significant decrease in UC-DAI was observed in pH-2.4 g and pH-3.6 g as compared to Placebo, but not in Time-2.25 g. No differences were observed in the safety profiles. Conclusions: Higher dose of the pH-dependent release formulation was more effective for induction of remission in patients with mild-to-moderate active UC. Additionally, the pH-dependent release formulation was preferable to the time-dependent release formulation for patients with proctitis-type UC (UMIN Clinical Trials Registry, no. C000000288). (Inflamm Bowel Dis 2010) PMID:20049950

Intracrine Androgens Enhance Decidualization and Modulate Expression of Human Endometrial Receptivity Genes

PubMed Central

Gibson, Douglas A.; Simitsidellis, Ioannis; Cousins, Fiona L.; Critchley, Hilary O. D.; Saunders, Philippa T. K.

2016-01-01

The endometrium is a complex, steroid-dependent tissue that undergoes dynamic cyclical remodelling. Transformation of stromal fibroblasts (ESC) into specialised secretory cells (decidualization) is fundamental to the establishment of a receptive endometrial microenvironment which can support and maintain pregnancy. Androgen receptors (AR) are present in ESC; in other tissues local metabolism of ovarian and adrenal-derived androgens regulate AR-dependent gene expression. We hypothesised that altered expression/activity of androgen biosynthetic enzymes would regulate tissue availability of bioactive androgens and the process of decidualization. Primary human ESC were treated in vitro for 1–8 days with progesterone and cAMP (decidualized) in the presence or absence of the AR antagonist flutamide. Time and treatment-dependent changes in genes essential for a) intra-tissue biosynthesis of androgens (5α-reductase/SRD5A1, aldo-keto reductase family 1 member C3/AKR1C3), b) establishment of endometrial decidualization (IGFBP1, prolactin) and c) endometrial receptivity (SPP1, MAOA, EDNRB) were measured. Decidualization of ESC resulted in significant time-dependent changes in expression of AKR1C3 and SRD5A1 and secretion of T/DHT. Addition of flutamide significantly reduced secretion of IGFBP1 and prolactin and altered the expression of endometrial receptivity markers. Intracrine biosynthesis of endometrial androgens during decidualization may play a key role in endometrial receptivity and offer a novel target for fertility treatment. PMID:26817618

Intracrine Androgens Enhance Decidualization and Modulate Expression of Human Endometrial Receptivity Genes.

PubMed

Gibson, Douglas A; Simitsidellis, Ioannis; Cousins, Fiona L; Critchley, Hilary O D; Saunders, Philippa T K

2016-01-28

The endometrium is a complex, steroid-dependent tissue that undergoes dynamic cyclical remodelling. Transformation of stromal fibroblasts (ESC) into specialised secretory cells (decidualization) is fundamental to the establishment of a receptive endometrial microenvironment which can support and maintain pregnancy. Androgen receptors (AR) are present in ESC; in other tissues local metabolism of ovarian and adrenal-derived androgens regulate AR-dependent gene expression. We hypothesised that altered expression/activity of androgen biosynthetic enzymes would regulate tissue availability of bioactive androgens and the process of decidualization. Primary human ESC were treated in vitro for 1-8 days with progesterone and cAMP (decidualized) in the presence or absence of the AR antagonist flutamide. Time and treatment-dependent changes in genes essential for a) intra-tissue biosynthesis of androgens (5α-reductase/SRD5A1, aldo-keto reductase family 1 member C3/AKR1C3), b) establishment of endometrial decidualization (IGFBP1, prolactin) and c) endometrial receptivity (SPP1, MAOA, EDNRB) were measured. Decidualization of ESC resulted in significant time-dependent changes in expression of AKR1C3 and SRD5A1 and secretion of T/DHT. Addition of flutamide significantly reduced secretion of IGFBP1 and prolactin and altered the expression of endometrial receptivity markers. Intracrine biosynthesis of endometrial androgens during decidualization may play a key role in endometrial receptivity and offer a novel target for fertility treatment.

Central Adiposity is Negatively Associated with Hippocampal-Dependent Relational Memory among Overweight and Obese Children

PubMed Central

Khan, Naiman A.; Baym, Carol L.; Monti, Jim M.; Raine, Lauren B.; Drollette, Eric S.; Scudder, Mark R.; Moore, R. Davis; Kramer, Arthur F.; Hillman, Charles H.; Cohen, Neal J.

2014-01-01

Objective To assess associations between adiposity and hippocampal-dependent and hippocampal-independent memory forms among prepubertal children. Study design Prepubertal children (7–9-year-olds, n = 126), classified as non-overweight (<85th %tile BMI-for-age [n = 73]) or overweight/obese (≥85th %tile BMI-for-age [n = 53]), completed relational (hippocampal-dependent) and item (hippocampal-independent) memory tasks, and performance was assessed with both direct (behavioral accuracy) and indirect (preferential disproportionate viewing [PDV]) measures. Adiposity (%whole body fat mass, subcutaneous abdominal adipose tissue, visceral adipose tissue, and total abdominal adipose tissue) was assessed using DXA. Backward regressions identified significant (P <0.05) predictive models of memory performance. Covariates included age, sex, pubertal timing, socioeconomic status, IQ, oxygen consumption (VO2max), and body mass index (BMI) z-score. Results Among overweight/obese children, total abdominal adipose tissue was a significant negative predictor of relational memory behavioral accuracy, and pubertal timing together with socioeconomic status jointly predicted the PDV measure of relational memory. In contrast, among non-overweight children, male sex predicted item memory behavioral accuracy, and a model consisting of socioeconomic status and BMI z-score jointly predicted the PDV measure of relational memory. Conclusions Regional, and not whole body, fat deposition was selectively and negatively associated with hippocampal-dependent relational memory among overweight/obese prepubertal children. PMID:25454939

Central adiposity is negatively associated with hippocampal-dependent relational memory among overweight and obese children.

PubMed

Khan, Naiman A; Baym, Carol L; Monti, Jim M; Raine, Lauren B; Drollette, Eric S; Scudder, Mark R; Moore, R Davis; Kramer, Arthur F; Hillman, Charles H; Cohen, Neal J

2015-02-01

To assess associations between adiposity and hippocampal-dependent and hippocampal-independent memory forms among prepubertal children. Prepubertal children (age 7-9 years; n = 126), classified as non-overweight (<85th percentile body mass index [BMI]-for-age [n = 73]) or overweight/obese (≥85th percentile BMI-for-age [n = 53]), completed relational (hippocampal-dependent) and item (hippocampal-independent) memory tasks. Performance was assessed with both direct (behavioral accuracy) and indirect (preferential disproportionate viewing [PDV]) measures. Adiposity (ie, percent whole-body fat mass, subcutaneous abdominal adipose tissue, visceral adipose tissue, and total abdominal adipose tissue) was assessed by dual-energy X-ray absorptiometry. Backward regression identified significant (P < .05) predictive models of memory performance. Covariates included age, sex, pubertal timing, socioeconomic status (SES), IQ, oxygen consumption, and BMI z-score. Among overweight/obese children, total abdominal adipose tissue was a significant negative predictor of relational memory behavioral accuracy, and pubertal timing together with SES jointly predicted the PDV measure of relational memory. In contrast, among non-overweight children, male sex predicted item memory behavioral accuracy, and a model consisting of SES and BMI z-score jointly predicted the PDV measure of relational memory. Regional, but not whole-body, fat deposition was selectively and negatively associated with hippocampal-dependent relational memory among overweight/obese prepubertal children. Copyright © 2015 Elsevier Inc. All rights reserved.

The Importance of Fine-Scale Flow Processes and Food Availability in the Maintenance of Soft-Sediment Communities

DTIC Science & Technology

1993-02-01

of the bottom sediments at a given site. From long time -series measurements of the flow and sediment-transport environment on Georges Bank...significantly affect flows and sediment transport depends, in part, on timing . Biological effects on seafloor stability may be more pronounced, for example...potentially can enhance particle retention time within the tube bed via skimming flow (described earlier), although it is unclear if natural populations of

[Cross-sectional study of informal caregiver burden and the determinants related to the care of dependent persons].

PubMed

Rodríguez-González, Ana María; Rodríguez-Míguez, Eva; Duarte-Pérez, Ana; Díaz-Sanisidro, Eduardo; Barbosa-Álvarez, Ángel; Clavería, Ana

2017-03-01

To describe the burden of informal carers of dependent people and to identify related variables. Descriptive observational cross-sectional study. Primary Health Care in the southern area of Pontevedra. 97 caregivers of dependent persons. We collected socioeconomic data and health conditions from caregivers and dependent persons, time spent on the daily care and caregiver burden (Zarit abbreviate) through a personal interview. Besides the description of the sample-including their burden level-, a contrast mean was used to identify characteristics that influenced in punctuation of Zarit scale. A logistic regression was used to analyse characteristics that increase the likelihood to experiment burden. 61.9% of caregivers are subject to intense burden. The item on the scale which contributes most to the caregiver burden is the lack of time for oneself, followed by the negative effects of interpersonal relationships. Contrast means shows that degree of relationship, number of care hours, caregiver health and aggressiveness of dependent persons produce significant differences in Zarit scale. Physic and psychological health of caregivers and aggressiveness of dependent persons is associated with the likelihood of developing caregiver burden. Informal caregivers of dependent persons show a high level of burden, both related to their characteristics and those of the dependent persons. Caregiver burden rethinks the need for public policies focused on dependence to adopt an integrative caregiver-dependent vision. Copyright © 2016 Elsevier España, S.L.U. All rights reserved.

Construction of a Penrose Diagram for a Spatially Coherent Evaporating Black Hole

NASA Technical Reports Server (NTRS)

Brown, Beth A.; Lindesay, James

2007-01-01

A Penrose diagram is constructed for an example black hole that evaporates at a steady rate as measured by a distant observer, until the mass vanishes, yielding a final state Minkowski space-time. Coordinate dependencies of significant features, such as the horizon and coordinate anomalies, are clearly demonstrated on the diagram. The large-scale causal structure of the space-time is briefly discussed.

Mycophenolic Acid Pharmacokinetics and Relapse in Children with Steroid–Dependent Idiopathic Nephrotic Syndrome

PubMed Central

Tellier, Stéphanie; Dallocchio, Aymeric; Guigonis, Vincent; Saint-Marcoux, Frank; Llanas, Brigitte; Ichay, Lydia; Bandin, Flavio; Godron, Astrid; Morin, Denis; Brochard, Karine; Gandia, Peggy; Bouchet, Stéphane; Marquet, Pierre; Decramer, Stéphane

2016-01-01

Background and objectives Therapeutic drug monitoring of mycophenolic acid can improve clinical outcome in organ transplantation and lupus, but data are scarce in idiopathic nephrotic syndrome. The aim of our study was to investigate whether mycophenolic acid pharmacokinetics are associated with disease control in children receiving mycophenolate mofetil for the treatment of steroid–dependent nephrotic syndrome. Design, setting, participants, & measurements This was a retrospective multicenter study including 95 children with steroid–dependent nephrotic syndrome treated with mycophenolate mofetil with or without steroids. Area under the concentration-time curve of mycophenolic acid was determined in all children on the basis of sampling times at 20, 60, and 180 minutes postdose, using Bayesian estimation. The association between a threshold value of the area under the concentration-time curve of mycophenolic acid and the relapse rate was assessed using a negative binomial model. Results In total, 140 areas under the concentration-time curve of mycophenolic acid were analyzed. The findings indicate individual dose adaptation in 53 patients (38%) to achieve an area under the concentration-time curve target of 30–60 mg·h/L. In a multivariable negative binomial model including sex, age at disease onset, time to start of mycophenolate mofetil, previous immunomodulatory treatment, and concomitant prednisone dose, a level of area under the concentration-time curve of mycophenolic acid >45 mg·h/L was significantly associated with a lower relapse rate (rate ratio, 0.65; 95% confidence interval, 0.46 to 0.89; P=0.01). Conclusions Therapeutic drug monitoring leading to individualized dosing may improve the efficacy of mycophenolate mofetil in steroid–dependent nephrotic syndrome. Additional prospective studies are warranted to determine the optimal target for area under the concentration-time curve of mycophenolic acid in this population. PMID:27445161

Mycophenolic Acid Pharmacokinetics and Relapse in Children with Steroid-Dependent Idiopathic Nephrotic Syndrome.

PubMed

Tellier, Stéphanie; Dallocchio, Aymeric; Guigonis, Vincent; Saint-Marcoux, Frank; Llanas, Brigitte; Ichay, Lydia; Bandin, Flavio; Godron, Astrid; Morin, Denis; Brochard, Karine; Gandia, Peggy; Bouchet, Stéphane; Marquet, Pierre; Decramer, Stéphane; Harambat, Jérôme

2016-10-07

Therapeutic drug monitoring of mycophenolic acid can improve clinical outcome in organ transplantation and lupus, but data are scarce in idiopathic nephrotic syndrome. The aim of our study was to investigate whether mycophenolic acid pharmacokinetics are associated with disease control in children receiving mycophenolate mofetil for the treatment of steroid-dependent nephrotic syndrome. This was a retrospective multicenter study including 95 children with steroid-dependent nephrotic syndrome treated with mycophenolate mofetil with or without steroids. Area under the concentration-time curve of mycophenolic acid was determined in all children on the basis of sampling times at 20, 60, and 180 minutes postdose, using Bayesian estimation. The association between a threshold value of the area under the concentration-time curve of mycophenolic acid and the relapse rate was assessed using a negative binomial model. In total, 140 areas under the concentration-time curve of mycophenolic acid were analyzed. The findings indicate individual dose adaptation in 53 patients (38%) to achieve an area under the concentration-time curve target of 30-60 mg·h/L. In a multivariable negative binomial model including sex, age at disease onset, time to start of mycophenolate mofetil, previous immunomodulatory treatment, and concomitant prednisone dose, a level of area under the concentration-time curve of mycophenolic acid >45 mg·h/L was significantly associated with a lower relapse rate (rate ratio, 0.65; 95% confidence interval, 0.46 to 0.89; P =0.01). Therapeutic drug monitoring leading to individualized dosing may improve the efficacy of mycophenolate mofetil in steroid-dependent nephrotic syndrome. Additional prospective studies are warranted to determine the optimal target for area under the concentration-time curve of mycophenolic acid in this population. Copyright © 2016 by the American Society of Nephrology.

CORRELATES OF RECOVERY FROM ALCOHOL DEPENDENCE: A PROSPECTIVE STUDY OVER A 3-YEAR FOLLOW-UP INTERVAL

PubMed Central

Dawson, Deborah A.; Goldstein, Risë B.; Ruan, W. June; Grant, Bridget F.

2011-01-01

Background Correlates of recovery from alcohol dependence have been identified through a variety of study designs characterized by different strengths and limitations. The goal of this study was to compare correlates of recovery based on a 3-year prospective design with those based on cross-sectional analyses of data from the same source. Methods Data from the 2001-2002 Wave 1 and 2004-2005 Wave 2 National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) were used to examine baseline characteristics associated with Wave 2 recovery from alcohol dependence, among those who classified with past-year DSM-IV alcohol dependence at Wave 1 (n=1,172). Results Abstinent recovery (AR) was significantly associated with Black/Asian/Hispanic race/ethnicity, children <1 year of age in the household at baseline, attending religious services ≥weekly at follow-up, and having initiated help seeking that comprised/included 12-step participation within <3 years prior to baseline. Nonabstinent recovery (NR) was positively associated with being never married at baseline, having job problems or being unemployed in the year preceding baseline, attending religious services

Task-dependent signal variations in EEG error-related potentials for brain-computer interfaces

NASA Astrophysics Data System (ADS)

Iturrate, I.; Montesano, L.; Minguez, J.

2013-04-01

Objective. A major difficulty of brain-computer interface (BCI) technology is dealing with the noise of EEG and its signal variations. Previous works studied time-dependent non-stationarities for BCIs in which the user’s mental task was independent of the device operation (e.g., the mental task was motor imagery and the operational task was a speller). However, there are some BCIs, such as those based on error-related potentials, where the mental and operational tasks are dependent (e.g., the mental task is to assess the device action and the operational task is the device action itself). The dependence between the mental task and the device operation could introduce a new source of signal variations when the operational task changes, which has not been studied yet. The aim of this study is to analyse task-dependent signal variations and their effect on EEG error-related potentials.Approach. The work analyses the EEG variations on the three design steps of BCIs: an electrophysiology study to characterize the existence of these variations, a feature distribution analysis and a single-trial classification analysis to measure the impact on the final BCI performance.Results and significance. The results demonstrate that a change in the operational task produces variations in the potentials, even when EEG activity exclusively originated in brain areas related to error processing is considered. Consequently, the extracted features from the signals vary, and a classifier trained with one operational task presents a significant loss of performance for other tasks, requiring calibration or adaptation for each new task. In addition, a new calibration for each of the studied tasks rapidly outperforms adaptive techniques designed in the literature to mitigate the EEG time-dependent non-stationarities.

Predation and fragmentation portrayed in the statistical structure of prey time series

PubMed Central

Hendrichsen, Ditte K; Topping, Chris J; Forchhammer, Mads C

2009-01-01

Background Statistical autoregressive analyses of direct and delayed density dependence are widespread in ecological research. The models suggest that changes in ecological factors affecting density dependence, like predation and landscape heterogeneity are directly portrayed in the first and second order autoregressive parameters, and the models are therefore used to decipher complex biological patterns. However, independent tests of model predictions are complicated by the inherent variability of natural populations, where differences in landscape structure, climate or species composition prevent controlled repeated analyses. To circumvent this problem, we applied second-order autoregressive time series analyses to data generated by a realistic agent-based computer model. The model simulated life history decisions of individual field voles under controlled variations in predator pressure and landscape fragmentation. Analyses were made on three levels: comparisons between predated and non-predated populations, between populations exposed to different types of predators and between populations experiencing different degrees of habitat fragmentation. Results The results are unambiguous: Changes in landscape fragmentation and the numerical response of predators are clearly portrayed in the statistical time series structure as predicted by the autoregressive model. Populations without predators displayed significantly stronger negative direct density dependence than did those exposed to predators, where direct density dependence was only moderately negative. The effects of predation versus no predation had an even stronger effect on the delayed density dependence of the simulated prey populations. In non-predated prey populations, the coefficients of delayed density dependence were distinctly positive, whereas they were negative in predated populations. Similarly, increasing the degree of fragmentation of optimal habitat available to the prey was accompanied with a shift in the delayed density dependence, from strongly negative to gradually becoming less negative. Conclusion We conclude that statistical second-order autoregressive time series analyses are capable of deciphering interactions within and across trophic levels and their effect on direct and delayed density dependence. PMID:19419539

Wave-vector and polarization dependent impedance model for a hexagonal periodic metasurface exemplified through finite-difference time-domain simulations.

PubMed

Ding, Yi S; He, Yang

2017-08-21

An isotropic impedance sheet model is proposed for a loop-type hexagonal periodic metasurface. Both frequency and wave-vector dispersion are considered near the resonance frequency. Therefore both the angle and polarization dependences of the metasurface impedance can be properly and simultaneously described in our model. The constitutive relation of this model is transformed into auxiliary differential equations which are integrated into the finite-difference time-domain algorithm. Finally, a finite large metasurface sample under oblique illumination is used to test the model and the algorithm. Our model and algorithm can significantly increase the accuracy of the homogenization methods for modeling periodic metasurfaces.

Other satellite atmospheres: Their nature and planetary interactions

NASA Technical Reports Server (NTRS)

Smyth, W. H.

1982-01-01

The Io sodium cloud model was successfully generated to include the time and spatial dependent lifetime sink produced by electron impact ionization as the plasma torus oscillates about the satellite plane, while simultaneously including the additional time dependence introduced by the action of solar radiation pressure on the cloud. Very preliminary model results are discussed and continuing progress in analysis of the peculiar directional features of the sodium cloud is also reported. Significant progress was made in developing a model for the Io potassium cloud and differences anticipated between the potassium and sodium cloud are described. An effort to understand the hydrogen atmosphere associated with Saturn's rings was initiated and preliminary results of a very and study are summarized.

A novel optical freezing array for the examination of cooling rate dependence in heterogeneous ice nucleation

NASA Astrophysics Data System (ADS)

Budke, Carsten; Dreischmeier, Katharina; Koop, Thomas

2014-05-01

Homogeneous ice nucleation is a stochastic process, implying that it is not only temperature but also time dependent. For heterogeneous ice nucleation it is still under debate whether there is a significant time dependence or not. In case of minor time dependence it is probably sufficient to use a singular or slightly modified singular approach, which mainly supposes temperature dependence and just small stochastic variations. We contribute to this discussion using a novel optical freezing array termed BINARY (Bielefeld Ice Nucleation ARraY). The setup consists of an array of microliter-sized droplets on a Peltier cooling stage. The droplets are separated from each other with a polydimethylsiloxane (PDMS) spacer to prevent a Bergeron-Findeisen process, in which the first freezing droplets grow at the expense of the remaining liquid ones due to their vapor pressure differences. An automatic detection of nucleation events is realized optically by the change in brightness during freezing. Different types of ice nucleating agents were tested with the presented setup, e. g. pollen and clay mineral dust. Exemplarily, cooling rate dependent measurements are shown for the heterogeneous ice nucleation induced by Snomax®. The authors gratefully acknowledge funding by the German Research Foundation (DFG) through the project BIOCLOUDS (KO 2944/1-1) and through the research unit INUIT (FOR 1525) under KO 2944/2-1. We particularly thank our INUIT partners for fruitful collaboration and sharing of ideas and IN samples.

Emotional intelligence and problem solving strategy: comparative study basedon "tower of hanoi" test.

PubMed

Arefnasab, Zahra; Zare, Hosein; Babamahmoodi, Abdolreza

2012-01-01

The aim of this study was to compare problem solving strategies between peoples with high and low emotional intelligence (EI). This study is a cross sectional descriptive study.The sample groups include senior BS& BA between 20-30 years old into two with high and low emotional intelligence, each group had 30 subjects.Data was analyzed with non-parametric chi square test for main dependent variable (problem solving strategies) and accessory dependent variables(manner of starting and fulfillmentof the test).The Independent two group T-test was used for analyzing other accessory dependent variables(Number of errors and total time used for fulfillment of the test). There was a significant difference between two groups in "number of errors" (t=-3.67,p=0) and "total time used for fulfillment of the test"(-6.17,p=0) and there was significant relation between EI and "problem solving strategies" (χ2=25.71, p<0.01) and (Cramer's v = 0.65, p<0.01) .Also there was significant relation between EI and "fulfillment of test" (χ2=20.31, p<0.01) and (φ=0.58, p<0.01). But the relation between EI and "manner of starting the test" was not significant (χ2=1.11, p=0.29). Subjects with high EI used more "insightful" strategy and subjects with low EI used more "trial- error" strategy. The first group completed the test more rapidlyand with fewer errors, compared with the second group. In addition the first group was more successful in performing the test than the second one. People with high EI significantly solve problems better than people with lowEI.

Direction dependence of displacement time for two-fluid electroosmotic flow.

PubMed

Lim, Chun Yee; Lam, Yee Cheong

2012-03-01

Electroosmotic flow that involves one fluid displacing another fluid is commonly encountered in various microfludic applications and experiments, for example, current monitoring technique to determine zeta potential of microchannel. There is experimentally observed anomaly in such flow, namely, the displacement time is flow direction dependent, i.e., it depends if it is a high concentration fluid displacing a low concentration fluid, or vice versa. Thus, this investigation focuses on the displacement flow of two fluids with various concentration differences. The displacement time was determined experimentally with current monitoring method. It is concluded that the time required for a high concentration solution to displace a low concentration solution is smaller than the time required for a low concentration solution to displace a high concentration solution. The percentage displacement time difference increases with increasing concentration difference and independent of the length or width of the channel and the voltage applied. Hitherto, no theoretical analysis or numerical simulation has been conducted to explain this phenomenon. A numerical model based on finite element method was developed to explain the experimental observations. Simulations showed that the velocity profile and ion distribution deviate significantly from a single fluid electroosmotic flow. The distortion of ion distribution near the electrical double layer is responsible for the displacement time difference for the two different flow directions. The trends obtained from simulations agree with the experimental findings.

Direction dependence of displacement time for two-fluid electroosmotic flow

PubMed Central

Lim, Chun Yee; Lam, Yee Cheong

2012-01-01

Electroosmotic flow that involves one fluid displacing another fluid is commonly encountered in various microfludic applications and experiments, for example, current monitoring technique to determine zeta potential of microchannel. There is experimentally observed anomaly in such flow, namely, the displacement time is flow direction dependent, i.e., it depends if it is a high concentration fluid displacing a low concentration fluid, or vice versa. Thus, this investigation focuses on the displacement flow of two fluids with various concentration differences. The displacement time was determined experimentally with current monitoring method. It is concluded that the time required for a high concentration solution to displace a low concentration solution is smaller than the time required for a low concentration solution to displace a high concentration solution. The percentage displacement time difference increases with increasing concentration difference and independent of the length or width of the channel and the voltage applied. Hitherto, no theoretical analysis or numerical simulation has been conducted to explain this phenomenon. A numerical model based on finite element method was developed to explain the experimental observations. Simulations showed that the velocity profile and ion distribution deviate significantly from a single fluid electroosmotic flow. The distortion of ion distribution near the electrical double layer is responsible for the displacement time difference for the two different flow directions. The trends obtained from simulations agree with the experimental findings. PMID:22662083

Context-Dependent Piano Music Transcription With Convolutional Sparse Coding

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

Cogliati, Andrea; Duan, Zhiyao; Wohlberg, Brendt

This study presents a novel approach to automatic transcription of piano music in a context-dependent setting. This approach employs convolutional sparse coding to approximate the music waveform as the summation of piano note waveforms (dictionary elements) convolved with their temporal activations (onset transcription). The piano note waveforms are pre-recorded for the specific piano to be transcribed in the specific environment. During transcription, the note waveforms are fixed and their temporal activations are estimated and post-processed to obtain the pitch and onset transcription. This approach works in the time domain, models temporal evolution of piano notes, and estimates pitches and onsetsmore » simultaneously in the same framework. Finally, experiments show that it significantly outperforms a state-of-the-art music transcription method trained in the same context-dependent setting, in both transcription accuracy and time precision, in various scenarios including synthetic, anechoic, noisy, and reverberant environments.« less

Shock temperatures in anorthite glass

NASA Technical Reports Server (NTRS)

Boslough, M. B.; Ahrens, T. J.; Mitchell, A. C.

1983-01-01

Temperatures of CaAl2Si2O8 (anorthite glass) shocked to pressures between 48 and 117 GPa were measured in the range from 2500 to 5600 K, using optical pyrometry techniques. The pressure dependence of the shock temperatures deviates significantly from predictions based on a single high pressure phase. At least three phase transitions, at pressures of about 55, 85, and 100 GPa and with transition energies of about 0.5 MJ/kg each (approximately 1.5 MJ/kg total) are required to explain the shock temperature data. The phase transition at 100 GPa can possibly be identified with the stishovite melting transition. Theoretical models of the time dependence of the thermal radiation from the shocked anorthite based on the geometry of the experiment and the absorptive properties of the shocked material yields good agreement with observations, indicating that it is not necessary to invoke intrinsic time dependences to explain the data in many cases.

Context-Dependent Piano Music Transcription With Convolutional Sparse Coding

DOE PAGES

Cogliati, Andrea; Duan, Zhiyao; Wohlberg, Brendt

2016-08-04

This study presents a novel approach to automatic transcription of piano music in a context-dependent setting. This approach employs convolutional sparse coding to approximate the music waveform as the summation of piano note waveforms (dictionary elements) convolved with their temporal activations (onset transcription). The piano note waveforms are pre-recorded for the specific piano to be transcribed in the specific environment. During transcription, the note waveforms are fixed and their temporal activations are estimated and post-processed to obtain the pitch and onset transcription. This approach works in the time domain, models temporal evolution of piano notes, and estimates pitches and onsetsmore » simultaneously in the same framework. Finally, experiments show that it significantly outperforms a state-of-the-art music transcription method trained in the same context-dependent setting, in both transcription accuracy and time precision, in various scenarios including synthetic, anechoic, noisy, and reverberant environments.« less

Effects of T'ai Chi on Serotonin, Nicotine Dependency, Depression, and Anger in Hospitalized Alcohol-Dependent Patients.

PubMed

Oh, Chung-Uk; Kim, Nam-Cho

2016-12-01

The aim of this study was to investigate the effects of t'ai chi on blood serotonin levels, nicotine dependence, depression, and anger in hospitalized alcohol-dependent patients. This study followed an experimental and nonequivalent control group in a non-synchronized design. It was performed in a hospital located in Young Ju city, Korea, from April to August 2013. Thirty-eight patients who were hospitalized with alcohol dependence were included. They were randomly divided into an experimental and a control group, with 19 patients in each group. Patients in the experimental group practiced the 24-posture yang style t'ai chi for 50 min three times per week for 8 weeks as part of the routine hospital rehabilitation program, and those in the control group followed only the routine hospital rehabilitation program. The effect of treatment was measured using blood serotonin levels and a questionnaire on nicotine dependence, depression, and anger. Both measurements were performed before and after 8 weeks of intervention. Data were analyzed using the t-test, chi-square test, and paired t-tests. The experimental group showed a significantly increased blood serotonin level (p = 0.001) and significantly reduced nicotine dependence, depression, and anger (p = 0.001) than the control group did after 8 weeks of treatment. T'ai chi was shown to be an effective nursing intervention in hospitalized alcohol-dependent patients.

Functional quantitative susceptibility mapping (fQSM).

PubMed

Balla, Dávid Z; Sanchez-Panchuelo, Rosa M; Wharton, Samuel J; Hagberg, Gisela E; Scheffler, Klaus; Francis, Susan T; Bowtell, Richard

2014-10-15

Blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) is a powerful technique, typically based on the statistical analysis of the magnitude component of the complex time-series. Here, we additionally interrogated the phase data of the fMRI time-series and used quantitative susceptibility mapping (QSM) in order to investigate the potential of functional QSM (fQSM) relative to standard magnitude BOLD fMRI. High spatial resolution data (1mm isotropic) were acquired every 3 seconds using zoomed multi-slice gradient-echo EPI collected at 7 T in single orientation (SO) and multiple orientation (MO) experiments, the latter involving 4 repetitions with the subject's head rotated relative to B0. Statistical parametric maps (SPM) were reconstructed for magnitude, phase and QSM time-series and each was subjected to detailed analysis. Several fQSM pipelines were evaluated and compared based on the relative number of voxels that were coincidentally found to be significant in QSM and magnitude SPMs (common voxels). We found that sensitivity and spatial reliability of fQSM relative to the magnitude data depended strongly on the arbitrary significance threshold defining "activated" voxels in SPMs, and on the efficiency of spatio-temporal filtering of the phase time-series. Sensitivity and spatial reliability depended slightly on whether MO or SO fQSM was performed and on the QSM calculation approach used for SO data. Our results present the potential of fQSM as a quantitative method of mapping BOLD changes. We also critically discuss the technical challenges and issues linked to this intriguing new technique. Copyright © 2014 Elsevier Inc. All rights reserved.

Load and Time Dependence of Interfacial Chemical Bond-Induced Friction at the Nanoscale.

PubMed

Tian, Kaiwen; Gosvami, Nitya N; Goldsby, David L; Liu, Yun; Szlufarska, Izabela; Carpick, Robert W

2017-02-17

Rate and state friction (RSF) laws are widely used empirical relationships that describe the macroscale frictional behavior of a broad range of materials, including rocks found in the seismogenic zone of Earth's crust. A fundamental aspect of the RSF laws is frictional "aging," where friction increases with the time of stationary contact due to asperity creep and/or interfacial strengthening. Recent atomic force microscope (AFM) experiments and simulations found that nanoscale silica contacts exhibit aging due to the progressive formation of interfacial chemical bonds. The role of normal load (and, thus, normal stress) on this interfacial chemical bond-induced (ICBI) friction is predicted to be significant but has not been examined experimentally. Here, we show using AFM that, for nanoscale ICBI friction of silica-silica interfaces, aging (the difference between the maximum static friction and the kinetic friction) increases approximately linearly with the product of the normal load and the log of the hold time. This behavior is attributed to the approximately linear dependence of the contact area on the load in the positive load regime before significant wear occurs, as inferred from sliding friction measurements. This implies that the average pressure, and thus the average bond formation rate, is load independent within the accessible load range. We also consider a more accurate nonlinear model for the contact area, from which we extract the activation volume and the average stress-free energy barrier to the aging process. Our work provides an approach for studying the load and time dependence of contact aging at the nanoscale and further establishes RSF laws for nanoscale asperity contacts.

Load and Time Dependence of Interfacial Chemical Bond-Induced Friction at the Nanoscale

NASA Astrophysics Data System (ADS)

Tian, Kaiwen; Gosvami, Nitya N.; Goldsby, David L.; Liu, Yun; Szlufarska, Izabela; Carpick, Robert W.

2017-02-01

Rate and state friction (RSF) laws are widely used empirical relationships that describe the macroscale frictional behavior of a broad range of materials, including rocks found in the seismogenic zone of Earth's crust. A fundamental aspect of the RSF laws is frictional "aging," where friction increases with the time of stationary contact due to asperity creep and/or interfacial strengthening. Recent atomic force microscope (AFM) experiments and simulations found that nanoscale silica contacts exhibit aging due to the progressive formation of interfacial chemical bonds. The role of normal load (and, thus, normal stress) on this interfacial chemical bond-induced (ICBI) friction is predicted to be significant but has not been examined experimentally. Here, we show using AFM that, for nanoscale ICBI friction of silica-silica interfaces, aging (the difference between the maximum static friction and the kinetic friction) increases approximately linearly with the product of the normal load and the log of the hold time. This behavior is attributed to the approximately linear dependence of the contact area on the load in the positive load regime before significant wear occurs, as inferred from sliding friction measurements. This implies that the average pressure, and thus the average bond formation rate, is load independent within the accessible load range. We also consider a more accurate nonlinear model for the contact area, from which we extract the activation volume and the average stress-free energy barrier to the aging process. Our work provides an approach for studying the load and time dependence of contact aging at the nanoscale and further establishes RSF laws for nanoscale asperity contacts.

Control of extracellular dopamine at dendrite and axon terminals

PubMed Central

Ford, Christopher P.; Gantz, Stephanie C.; Phillips, Paul E. M.; Williams, John T.

2010-01-01

Midbrain dopamine neurons release dopamine from both axons and dendrites. The mechanism underlying release at these different sites has been proposed to differ. This study used electrochemical and electrophysiological methods to compare the time course and calcium-dependence of somatodendritc dopamine release in the ventral tegmental area (VTA) and substantia nigra pars compacta (SNc) to that of axonal dopamine release in the dorsal striatum. The amount of dopamine released in the striatum was ~20 fold greater than in cell body regions of the VTA or SNc. However the calcium dependence and time to peak of the dopamine transients were similar. These results illustrate an unexpected overall similarity in the mechanisms of dopamine release in the striatum and cell body regions. To examine how diffusion regulates the time course of dopamine following release, dextran was added to the extracellular solution to slow diffusion. In the VTA, dextran slowed the rate of rise and fall of the extracellular dopamine transient as measured by fast-scan cyclic voltammetry (FSCV) yet did not alter the kinetics of the dopamine dependent inhibitory post-synaptic current (IPSC). Dextran failed to significantly alter the time course of the rise and fall of the dopamine transient in the striatum suggesting a more influential role for reuptake in the striatum. The conclusion is that the time course of dopamine within the extracellular space of the VTA is dependent on both diffusion and reuptake, whereas the activation of D2-receptors on dopamine neurons is primarily limited by reuptake. PMID:20484639

Pavlovian-to-instrumental transfer effects in the nucleus accumbens relate to relapse in alcohol dependence.

PubMed

Garbusow, Maria; Schad, Daniel J; Sebold, Miriam; Friedel, Eva; Bernhardt, Nadine; Koch, Stefan P; Steinacher, Bruno; Kathmann, Norbert; Geurts, Dirk E M; Sommer, Christian; Müller, Dirk K; Nebe, Stephan; Paul, Sören; Wittchen, Hans-Ulrich; Zimmermann, Ulrich S; Walter, Henrik; Smolka, Michael N; Sterzer, Philipp; Rapp, Michael A; Huys, Quentin J M; Schlagenhauf, Florian; Heinz, Andreas

2016-05-01

In detoxified alcohol-dependent patients, alcohol-related stimuli can promote relapse. However, to date, the mechanisms by which contextual stimuli promote relapse have not been elucidated in detail. One hypothesis is that such contextual stimuli directly stimulate the motivation to drink via associated brain regions like the ventral striatum and thus promote alcohol seeking, intake and relapse. Pavlovian-to-Instrumental-Transfer (PIT) may be one of those behavioral phenomena contributing to relapse, capturing how Pavlovian conditioned (contextual) cues determine instrumental behavior (e.g. alcohol seeking and intake). We used a PIT paradigm during functional magnetic resonance imaging to examine the effects of classically conditioned Pavlovian stimuli on instrumental choices in n = 31 detoxified patients diagnosed with alcohol dependence and n = 24 healthy controls matched for age and gender. Patients were followed up over a period of 3 months. We observed that (1) there was a significant behavioral PIT effect for all participants, which was significantly more pronounced in alcohol-dependent patients; (2) PIT was significantly associated with blood oxygen level-dependent (BOLD) signals in the nucleus accumbens (NAcc) in subsequent relapsers only; and (3) PIT-related NAcc activation was associated with, and predictive of, critical outcomes (amount of alcohol intake and relapse during a 3 months follow-up period) in alcohol-dependent patients. These observations show for the first time that PIT-related BOLD signals, as a measure of the influence of Pavlovian cues on instrumental behavior, predict alcohol intake and relapse in alcohol dependence. © 2015 Society for the Study of Addiction.

Arylamine N-acetyltransferase 2 genotype-dependent N-acetylation of isoniazid in cryopreserved human hepatocytes.

PubMed

Doll, Mark A; Salazar-González, Raúl A; Bodduluri, Srineil; Hein, David W

2017-07-01

Cryopreserved human hepatocytes were used to investigate the role of arylamine N -acetyltransferase 2 (NAT2; EC 2.3.1.5) polymorphism on the N -acetylation of isoniazid (INH). NAT2 genotype was determined by Taqman allelic discrimination assay and INH N -acetylation was measured by high performance liquid chromatography. INH N -acetylation rates in vitro exhibited a robust and highly significant ( P <0.005) NAT2 phenotype-dependent metabolism. N -acetylation rates in situ were INH concentration- and time-dependent. Following incubation for 24 h with 12.5 or 100 µmol/L INH, acetyl-INH concentrations varied significantly ( P = 0.0023 and P = 0.0002) across cryopreserved human hepatocytes samples from rapid, intermediate, and slow acetylators, respectively. The clear association between NAT2 genotype and phenotype supports use of NAT2 genotype to guide INH dosing strategies in the treatment and prevention of tuberculosis.

Impact of the single point of access referral system to reduce waiting times and improve clinical outcomes in an assistive technology service.

PubMed

Hosking, Jonathan; Gibson, Colin

2016-07-01

The introduction of a single point referral system that prioritises clients depending on case complexity and overcomes the need for re-admittance to a waiting list via a review system has been shown to significantly reduce maximum waiting times for a Posture and Mobility (Special Seating) Service from 102.0 ± 24.33 weeks to 19.2 ± 8.57 weeks (p = 0.015). Using this service model linear regression revealed a statistically significant improvement in the performance outcome of prescribed seating solutions with shorter Episode of Care completion times (p = 0.023). In addition, the number of Episodes of Care completed per annum was significantly related to the Episode of Care completion time (p = 0.019). In conclusion, it is recommended that it may be advantageous to apply this service model to other assistive technology services in order to reduce waiting times and to improve clinical outcomes.

Quality of life in a cohort of high-dose benzodiazepine dependent patients.

PubMed

Lugoboni, Fabio; Mirijello, Antonio; Faccini, Marco; Casari, Rebecca; Cossari, Anthony; Musi, Gessica; Bissoli, Giorgia; Quaglio, Gianluca; Addolorato, Giovanni

2014-09-01

Benzodiazepines (BZD) are among the most widely prescribed drugs in developed countries. Since BZD can produce tolerance and dependence even in a short time, their use is recommended for a very limited time. However, these recommendations have been largely disregarded. The chronic use of BZD causes a number of serious side effects, i.e., cognitive impairment, falls, traffic accidents, dependence and tolerance. The aim of the present study was to evaluate quality of life (QoL) in a cohort of 62 consecutive high-dose BZD-dependent patients seeking a BZD detoxification. Patients seeking BZD detoxification were evaluated using the General Health Questionnaire (GHQ-12) and the short form-36 questionnaire (SF-36). Patients showed a significant reduction of QoL as measured by either SF-36 or GHQ-12. In particular, the greater impairment was observed in the items exploring physical and emotional status. Physical functioning was the item more influenced by the length of BZD abuse. Female patients showed a greater reduction of QoL compared to male, at least in some of the explored items. Social functioning scores were greatly reduced. The present study shows for the first time that high-doses BZD dependent patients have a reduced QoL and a reduced social functioning, along with high levels of psychological distress. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Craving and subsequent opioid use among opioid dependent patients who initiate treatment with buprenorphine

PubMed Central

Tsui, Judith I.; Anderson, Bradley J.; Strong, David R.; Stein, Michael D.

2016-01-01

Background Few studies have directly assessed associations between craving and subsequent opioid use among treated patients. Our objective was to prospectively evaluate the relative utility of two craving questionnaires to predict opioid use among opioid dependent patients in treatment. Method Opioid dependent patients (n=147) initiating buprenorphine treatment were assessed for three months. Craving was measured using: 1) the Desires for Drug Questionnaire (DDQ) and 2) the Penn Alcohol-Craving Scale adapted for opioid craving (PCS) for this study. Multi-level logistic regression models estimated the effects of craving on the likelihood of opioid use after adjusting for gender, age, ethnicity, education, opioid of choice, frequency of use, pain and depression. In these analyses craving assessed at time t was entered as a time-varying predictor of opioid use at time t+1. Results In adjusted regression models, a 1-point increase in PCS scores (on a 7-point scale) was associated with a significant increase in the odds of opioid use at the subsequent assessment (OR = 1.27, 95% CI 1.08; 1.49, p < .01). The odds of opioid use at the subsequent follow-up assessment increased significantly as DDQ desire and intention scores increased (OR = 1.25, 95%CI 1.03; 1.51, p< .05), but was not associated significantly with DDQ negative reinforcement (OR = 1.01, 95%CI 0.88; 1.17, p > .05) or DDQ control (OR = 0.97, 95%CI 0.85; 1.11, p > .05) scores. Conclusion Self-reported craving for opioids was associated with subsequent lapse to opioid use among a cohort of patients treated with buprenorphine. PMID:24521036

Controlling Nutritional Status (CONUT) score is a prognostic marker for gastric cancer patients after curative resection.

PubMed

Kuroda, Daisuke; Sawayama, Hiroshi; Kurashige, Junji; Iwatsuki, Masaaki; Eto, Tsugio; Tokunaga, Ryuma; Kitano, Yuki; Yamamura, Kensuke; Ouchi, Mayuko; Nakamura, Kenichi; Baba, Yoshifumi; Sakamoto, Yasuo; Yamashita, Yoichi; Yoshida, Naoya; Chikamoto, Akira; Baba, Hideo

2018-03-01

Controlling Nutritional Status (CONUT), as calculated from serum albumin, total cholesterol concentration, and total lymphocyte count, was previously shown to be useful for nutritional assessment. The current study investigated the potential use of CONUT as a prognostic marker in gastric cancer patients after curative resection. Preoperative CONUT was retrospectively calculated in 416 gastric cancer patients who underwent curative resection at Kumamoto University Hospital from 2005 to 2014. The patients were divided into two groups: CONUT-high (≥4) and CONUT-low (≤3), according to time-dependent receiver operating characteristic (ROC) analysis. The associations of CONUT with clinicopathological factors and survival were evaluated. CONUT-high patients were significantly older (p < 0.001) and had a lower body mass index (p = 0.019), deeper invasion (p < 0.001), higher serum carcinoembryonic antigen (p = 0.037), and higher serum carbohydrate antigen 19-9 (p = 0.007) compared with CONUT-low patients. CONUT-high patients had significantly poorer overall survival (OS) compared with CONUT-low patients according to univariate and multivariate analyses (hazard ratio: 5.09, 95% confidence interval 3.12-8.30, p < 0.001). In time-dependent ROC analysis, CONUT had a higher area under the ROC curve (AUC) for the prediction of 5-year OS than the neutrophil lymphocyte ratio, the Modified Glasgow Prognostic Score, or pStage. When the time-dependent AUC curve was used to predict OS, CONUT tended to maintain its predictive accuracy for long-term survival at a significantly higher level for an extended period after surgery when compared with the other markers tested. CONUT is useful for not only estimating nutritional status but also for predicting long-term OS in gastric cancer patients after curative resection.

Examining acute rehabilitation outcomes for children with total functional dependence after traumatic brain injury: a pilot study.

PubMed

Kramer, Megan E; Suskauer, Stacy J; Christensen, James R; DeMatt, Ellen J; Trovato, Melissa K; Salorio, Cynthia F; Slomine, Beth S

2013-01-01

To examine in a pilot cohort factors associated with functional outcome at discharge and 3-month follow-up after discharge from inpatient rehabilitation in children with severe traumatic brain injury (TBI) who entered rehabilitation with the lowest level of functional skills. Thirty-nine children and adolescents (3-18 years old) who sustained a severe TBI and had the lowest possible rating at rehabilitation admission on the Functional Independence Measure for Children (total score = 18). Retrospective review of data collected as part of routine clinical care. At discharge, 59% of the children were partially dependent for basic activities, while 41% remained dependent for basic activities. Initial Glasgow Coma Scale score, time to follow commands, and time from injury to rehabilitation admission were correlated with functional status at discharge. Time to follow commands and time from injury to rehabilitation admission were correlated with functional status at 3-month follow-up. Changes in functional status during the first few weeks of admission were associated with functional status at discharge and follow-up. Even children with the most severe brain injuries, who enter rehabilitation completely dependent for all daily activities, have the potential to make significant gains in functioning by discharge and in the following few months. Assessment of functional status early in the course of rehabilitation contributes to the ability to predict outcome from severe TBI.

Creating Situational Awareness in Spacecraft Operations with the Machine Learning Approach

NASA Astrophysics Data System (ADS)

Li, Z.

2016-09-01

This paper presents a machine learning approach for the situational awareness capability in spacecraft operations. There are two types of time dependent data patterns for spacecraft datasets: the absolute time pattern (ATP) and the relative time pattern (RTP). The machine learning captures the data patterns of the satellite datasets through the data training during the normal operations, which is represented by its time dependent trend. The data monitoring compares the values of the incoming data with the predictions of machine learning algorithm, which can detect any meaningful changes to a dataset above the noise level. If the difference between the value of incoming telemetry and the machine learning prediction are larger than the threshold defined by the standard deviation of datasets, it could indicate the potential anomaly that may need special attention. The application of the machine-learning approach to the Advanced Himawari Imager (AHI) on Japanese Himawari spacecraft series is presented, which has the same configuration as the Advanced Baseline Imager (ABI) on Geostationary Environment Operational Satellite (GOES) R series. The time dependent trends generated by the data-training algorithm are in excellent agreement with the datasets. The standard deviation in the time dependent trend provides a metric for measuring the data quality, which is particularly useful in evaluating the detector quality for both AHI and ABI with multiple detectors in each channel. The machine-learning approach creates the situational awareness capability, and enables engineers to handle the huge data volume that would have been impossible with the existing approach, and it leads to significant advances to more dynamic, proactive, and autonomous spacecraft operations.

Threshold network of a financial market using the P-value of correlation coefficients

NASA Astrophysics Data System (ADS)

Ha, Gyeong-Gyun; Lee, Jae Woo; Nobi, Ashadun

2015-06-01

Threshold methods in financial networks are important tools for obtaining important information about the financial state of a market. Previously, absolute thresholds of correlation coefficients have been used; however, they have no relation to the length of time. We assign a threshold value depending on the size of the time window by using the P-value concept of statistics. We construct a threshold network (TN) at the same threshold value for two different time window sizes in the Korean Composite Stock Price Index (KOSPI). We measure network properties, such as the edge density, clustering coefficient, assortativity coefficient, and modularity. We determine that a significant difference exists between the network properties of the two time windows at the same threshold, especially during crises. This implies that the market information depends on the length of the time window when constructing the TN. We apply the same technique to Standard and Poor's 500 (S&P500) and observe similar results.

Work time control and mental health of workers working long hours: the role of gender and age.

PubMed

Zołnierczyk-Zreda, Dorota; Bedyńska, Sylwia; Warszewska-Makuch, Magdalena

2012-01-01

The aim of this study was to examine the relationship between work time control and mental health in workers working long hours. The study also attempted to show how that relationship depended on age and gender. Three hundred and six white-collar workers doing clerical work for over 8 h daily were diagnosed on work time control and mental health with the 28-item General Health Questionnaire. The results of an analysis of variance (ANOVA) showed that participants working long hours but having high control over their work time had a significantly higher level of their mental health with regard to somatic complaints and anxiety and marginally higher with regard to social dysfunction than workers with low control over their work time. Male and female workers reported different problems with their mental health depending on what age (stage of life) they were at. It is hypothesized that the work-family conflict, inability to fulfil social commitments and poor working conditions can influence those effects.

Randomized controlled trial of attention bias modification in a racially diverse, socially anxious, alcohol dependent sample.

PubMed

Clerkin, Elise M; Magee, Joshua C; Wells, Tony T; Beard, Courtney; Barnett, Nancy P

2016-12-01

Attention biases may be an important treatment target for both alcohol dependence and social anxiety. This is the first ABM trial to investigate two (vs. one) targets of attention bias within a sample with co-occurring symptoms of social anxiety and alcohol dependence. Additionally, we used trial-level bias scores (TL-BS) to capture the phenomena of attention bias in a more ecologically valid, dynamic way compared to traditional attention bias scores. Adult participants (N = 86; 41% Female; 52% African American; 40% White) with elevated social anxiety symptoms and alcohol dependence were randomly assigned to an 8-session training condition in this 2 (Social Anxiety ABM vs. Social Anxiety Control) by 2 (Alcohol ABM vs. Alcohol Control) design. Symptoms of social anxiety, alcohol dependence, and attention bias were assessed across time. Multilevel models estimated the trajectories for each measure within individuals, and tested whether these trajectories differed according to the randomized training conditions. Across time, there were significant or trending decreases in all attention TL-BS parameters (but not traditional attention bias scores) and most symptom measures. However, there were not significant differences in the trajectories of change between any ABM and control conditions for any symptom measures. These findings add to previous evidence questioning the robustness of ABM and point to the need to extend the effects of ABM to samples that are racially diverse and/or have co-occurring psychopathology. The results also illustrate the potential importance of calculating trial-level attention bias scores rather than only including traditional bias scores. Copyright © 2016 Elsevier Ltd. All rights reserved.

Randomized Controlled Trial of Attention Bias Modification in a Racially Diverse, Socially Anxious, Alcohol Dependent Sample

PubMed Central

Clerkin, Elise M.; Magee, Joshua C.; Wells, Tony T.; Beard, Courtney; Barnett, Nancy P.

2016-01-01

Objective Attention biases may be an important treatment target for both alcohol dependence and social anxiety. This is the first ABM trial to investigate two (vs. one) targets of attention bias within a sample with co-occurring symptoms of social anxiety and alcohol dependence. Additionally, we used trial-level bias scores (TL-BS) to capture the phenomena of attention bias in a more ecologically valid, dynamic way compared to traditional attention bias scores. Method Adult participants (N=86; 41% Female; 52% African American; 40% White) with elevated social anxiety symptoms and alcohol dependence were randomly assigned to an 8-session training condition in this 2 (Social Anxiety ABM vs. Social Anxiety Control) by 2 (Alcohol ABM vs. Alcohol Control) design. Symptoms of social anxiety, alcohol dependence, and attention bias were assessed across time. Results Multilevel models estimated the trajectories for each measure within individuals, and tested whether these trajectories differed according to the randomized training conditions. Across time, there were significant or trending decreases in all attention TL-BS parameters (but not traditional attention bias scores) and most symptom measures. However, there were not significant differences in the trajectories of change between any ABM and control conditions for any symptom measures. Conclusions These findings add to previous evidence questioning the robustness of ABM and point to the need to extend the effects of ABM to samples that are racially diverse and/or have co-occurring psychopathology. The results also illustrate the potential importance of calculating trial-level attention bias scores rather than only including traditional bias scores. PMID:27591918

Learning enhances intrinsic excitability in a subset of lateral amygdala neurons

PubMed Central

Sehgal, Megha; Ehlers, Vanessa L.; Moyer, James R.

2014-01-01

Learning-induced modulation of neuronal intrinsic excitability is a metaplasticity mechanism that can impact the acquisition of new memories. Although the amygdala is important for emotional learning and other behaviors, including fear and anxiety, whether learning alters intrinsic excitability within the amygdala has received very little attention. Fear conditioning was combined with intracellular recordings to investigate the effects of learning on the intrinsic excitability of lateral amygdala (LA) neurons. To assess time-dependent changes, brain slices were prepared either immediately or 24-h post-conditioning. Fear conditioning significantly enhanced excitability of LA neurons, as evidenced by both decreased afterhyperpolarization (AHP) and increased neuronal firing. These changes were time-dependent such that reduced AHPs were evident at both time points whereas increased neuronal firing was only observed at the later (24-h) time point. Moreover, these changes occurred within a subset (32%) of LA neurons. Previous work also demonstrated that learning-related changes in synaptic plasticity are also evident in less than one-third of amygdala neurons, suggesting that the neurons undergoing intrinsic plasticity may be critical for fear memory. These data may be clinically relevant as enhanced LA excitability following fear learning could influence future amygdala-dependent behaviors. PMID:24554670

Context-Dependent Learning in People With Parkinson's Disease.

PubMed

Lee, Ya-Yun; Winstein, Carolee J; Gordon, James; Petzinger, Giselle M; Zelinski, Elizabeth M; Fisher, Beth E

2016-01-01

Context-dependent learning is a phenomenon in which people demonstrate superior performance in the context in which they originally learned a skill but perform less well in a novel context. This study investigated context-dependent learning in people with Parkinson's disease (PD) and age-matched nondisabled adults. All participants practiced 3 finger sequences, each embedded within a unique context (colors and locations on a computer screen). One day after practice, the participants were tested either under the sequence-context associations remained the same as during practice, or the sequence-context associations were changed (SWITCH). Compared with nondisabled adults, people with PD demonstrated significantly greater decrement in performance (especially movement time) under the SWITCH condition, suggesting that individuals with PD are more context dependent than nondisabled adults.

Assessment and management of alcohol dependence and withdrawal in the acute hospital: concise guidance.

PubMed

Stewart, Stephen; Swain, Sharon

2012-06-01

Alcohol dependence is common among patients attending acute hospitals. It can be the major reason for attendance or a significant cofactor. Assessment of these patients in the acute setting can be challenging owing to the multidisciplinary approach required. Doctors in acute hospitals are often inexperienced in managing dependence, a mental health problem. They might focus on the physical harms or the withdrawal, a consequence of the dependence. For this reason, assessment of dependence and prevention and management of acute alcohol withdrawal are often suboptimal. There is little existing guidance on how to manage this patient population, especially in non-specialist settings. With recently published National Institute for Health and Clinical Excellence (NICE) guidance on the management of dependence and withdrawal, now is the perfect time to produce concise guidelines in the hope that a more succinct suite of guidance can reach a larger audience.

Changes in glutamate receptor subunits within the medulla in goats after section of the carotid sinus nerves

PubMed Central

Miller, Justin Robert; Neumueller, Suzanne; Muere, Clarissa; Olesiak, Samantha; Pan, Lawrence; Bukowy, John D.; Daghistany, Asem O.; Hodges, Matthew R.

2014-01-01

The mechanisms which contribute to the time-dependent recovery of resting ventilation and the ventilatory CO2 chemoreflex after carotid body denervation (CBD) are poorly understood. Herein we tested the hypothesis that there are time-dependent changes in the expression of specific AMPA, NMDA, and/or neurokinin-1 (NK1R) receptors within respiratory-related brain stem nuclei acutely or chronically after CBD in adult goats. Brain stem tissues were collected acutely (5 days) or chronically (30 days) after sham or bilateral CBD, immunostained with antibodies targeting AMPA (GluA1 or GluA2), NMDA (GluN1), or NK-1 receptors, and optical density (OD) compared. Physiological measurement confirmed categorization of each group and showed ventilatory effects consistent with bilateral CBD (Miller et al. J Appl Physiol 115: 1088–1098, 2013). Acutely after CBD, GluA1 OD was unchanged or slightly increased, but GluA2 and GluN1 OD were reduced 15–30% within the nucleus tractus solitarius (NTS) and in other medullary respiratory nuclei. Chronically after CBD, GluA1 was reduced (P < 0.05) within the caudal NTS and in other nuclei, but there was significant recovery of GluA2 and GluN1 OD. NK1 OD was not significantly different from control after CBD. We conclude that the initial decrease in GluA2 and GluN1 after CBD likely contributes to hypoventilation and the reduced CO2 chemoreflex. The partial recovery of ventilation and the CO2 chemoreflex after CBD parallel a time-dependent return of these receptors to near control levels but likely depend upon additional initiating and maintenance factors for neuroplasticity. PMID:24790015

Temporal trends and variability of colonoscopy performance in a gastroenterology practice.

PubMed

le Clercq, Chantal M C; Mooi, Rick J; Winkens, Bjorn; Salden, Bouke N H; Bakker, C Minke; van Nunen, Annick B; Keulen, Eric P T; de Ridder, Rogier J; Masclee, Ad A M; Sanduleanu, Silvia

2016-03-01

Quality measures for colonoscopy are operator dependent and vary. It is unclear whether quality measures change over time. In this study, time-dependent variation in colonoscopy performance was examined in a gastroenterology practice. Colonoscopy and histopathology records that were collected at three hospitals (one university and two non-university hospitals) over three time periods (2007, 2010, and 2013) were reviewed. Data from colonoscopists performing at least 100 procedures per year were analyzed. Inter-colonoscopist variation in performance (i. e. adjusted cecal intubation rate [aCIR], adenoma detection rate [ADR], advanced ADR, mean adenomas per procedure [MAP], proximal ADR, nonpolypoid ADR, and serrated polyp detection rate) were examined using coefficients of variation. Logistic regression analyses were also performed, adjusting for covariates. A total of 23 colonoscopists performing 6400 procedures were included. Overall, the mean aCIR, ADR, MAP, and proximal ADR improved significantly over time, from 91.9 %, 22.5 %, 0.37, and 10.2 % in 2007 to 95.3 %, 25.8 %, 0.45, and 13.4 %, respectively, in 2013 (P < 0.05). The inter-colonoscopist variation in ADR decreased from 37 % in 2007 to 15 % in 2013 (P < 0.05). In the non-university hospitals, mean values for quality measures increased significantly over time, whereas they remained stable in the university hospital. Variability in performance among colonoscopists decreased significantly within the gastroenterology clinical practice. Core quality measures improved over time, mainly through improvement of the lower performers. Measurement of inter-colonoscopist variation in performance helps to identify factors that stimulate or hinder performance, and forms the basis for interventions. http://www.trialregister.nl. © Georg Thieme Verlag KG Stuttgart · New York.

Detonation Shock Dynamics Calibration for Non-Ideal HE: ANFO

NASA Astrophysics Data System (ADS)

Short, Mark; Salyer, Terry

2009-06-01

The detonation of ammonium nitrate (AN) and fuel-oil (FO) mixtures (ANFO) is significantly influenced by the properties of the AN (porosity, particle size, coating) and fuel-oil stoichiometry. We report on a new series of rate-stick experiments in cardboard confinement that highlight detonation front speed and curvature dependence on AN/FO stoichiometry and AN particle properties. Standard detonation velocity-curvature calibrations to the experimental data will be presented, as well as higher-order time-dependent detonation shock dynamics calibrations.

Simple and flexible SAS and SPSS programs for analyzing lag-sequential categorical data.

PubMed

O'Connor, B P

1999-11-01

This paper describes simple and flexible programs for analyzing lag-sequential categorical data, using SAS and SPSS. The programs read a stream of codes and produce a variety of lag-sequential statistics, including transitional frequencies, expected transitional frequencies, transitional probabilities, adjusted residuals, z values, Yule's Q values, likelihood ratio tests of stationarity across time and homogeneity across groups or segments, transformed kappas for unidirectional dependence, bidirectional dependence, parallel and nonparallel dominance, and significance levels based on both parametric and randomization tests.

Disruption of the Putative Vascular Leak Peptide Sequence in the Stabilized Ricin Vaccine Candidate RTA1-33/44-198

DTIC Science & Technology

2013-01-29

Time- dependence of calculated LD50. The data shown in Panel A were submitted to probit analysis to determine the LD50 of ricin at every 0.5-day...degenerate neutrophils and necrotic debris evident; (C) Only a limited region of the epithelium lining a bronchus remains viable (arrowheads); the...quantitative analysis of the dose dependent protective effects of the immunizations. All vaccine doses (2.5, 10 or 40 μg immunogen) resulted in significant

Intraspecific Variation in and Environment-Dependent Resource Allocation to Embryonic Development Time in Common Terns.

PubMed

Vedder, Oscar; Kürten, Nathalie; Bouwhuis, Sandra

Embryonic development time is thought to impact life histories through trade-offs against life-history traits later in life, yet the inference is based on interspecific comparative analyses only. It is largely unclear whether intraspecific variation in embryonic development time that is not caused by environmental differences occurs, which would be required to detect life-history trade-offs. Here we performed a classical common-garden experiment by incubating fresh eggs of free-living common terns (Sterna hirundo) in a controlled incubation environment at two different temperatures. Hatching success was high but was slightly lower at the lower temperature. While correcting for effects of year, incubation temperature, and laying order, we found significant variation in the incubation time embryos required until hatching and in their heart rate. Embryonic heart rate was significantly positively correlated within clutches, and a similar tendency was found for incubation time, suggesting that intrinsic differences in embryonic development rate between offspring of different parents exist. Incubation time and embryonic heart rate were strongly correlated: embryos with faster heart rates required shorter incubation time. However, after correction for heart rate, embryos still required more time for development at the lower incubation temperature. This suggests that processes other than development require a greater share of resources in a suboptimal environment and that relative resource allocation to development is, therefore, environment dependent. We conclude that there is opportunity to detect intraspecific life-history trade-offs with embryonic development time and that the resolution of trade-offs may differ between embryonic environments.

Effects of acetaminophen and ibuprofen in children with migraine receiving preventive treatment with magnesium.

PubMed

Gallelli, Luca; Avenoso, Tiziana; Falcone, Daniela; Palleria, Caterina; Peltrone, Francesco; Esposito, Maria; De Sarro, Giovambattista; Carotenuto, Marco; Guidetti, Vincenzo

2014-02-01

The purpose of this study was to evaluate both the effects of ibuprofen and/or acetaminophen for the acute treatment of primary migraine in children in or out prophylactic treatment with magnesium. Children ranging from the ages of 5 to 16 years with at least 4 attack/month of primary migraine were eligible for participation the study. A visual analog scale was used to evaluate pain intensity at the moment of admission to the study (start of the study) and every month up to 18 months later (end of the study). One hundred sixty children of both sexes aged 5-16 years were enrolled and assigned in 4 groups to receive a treatment with acetaminophen or ibuprofen without or with magnesium. Migraine pain endurance and monthly frequency were similar in the 4 groups. Both acetaminophen and ibuprofen induced a significant decrease in pain intensity (P < .01), without a time-dependent correlation, but did not modify its frequency. Magnesium pretreatment induced a significant decrease in pain intensity (P < .01) without a time-dependent correlation in both acetaminophen- and ibuprofen-treated children and also significantly reduced (P < .01) the pain relief timing during acetaminophen but not during ibuprofen treatment (P < .01). In both acetaminophen and ibuprofen groups, magnesium pretreatment significantly reduced the pain frequency (P < .01). Magnesium increased the efficacy of ibuprofen and acetaminophen with not age-related effects. © 2013 American Headache Society.

The effect of UV-Vis to near-infrared light on the biological response of human dental pulp cells

NASA Astrophysics Data System (ADS)

Hadis, Mohammed A.; Cooper, Paul R.; Milward, Michael R.; Gorecki, Patricia; Tarte, Edward; Churm, James; Palin, William M.

2015-03-01

Human dental pulp cells (DPCs) were isolated and cultured in phenol-red-free α-MEM/10%-FCS at 37ºC in 5% CO2. DPCs at passages 2-4 were seeded (150μL; 25,000 cell/ml) in black 96-microwell plates with transparent bases. 24h post-seeding, cultures were irradiated using a bespoke LED array consisting of 60 LEDs (3.5mW/cm2) of wavelengths from 400-900nm (10 wavelengths, n=6) for time intervals of up to 120s. Metabolic and mitochondrial activity was assessed via a modified MTT assay. Statistical differences were identified using multi-factorial analysis of variance and post-hoc Tukey tests (P=0.05). The biological responses were significantly dependent upon post-irradiation incubation period, wavelength and exposure time (P<0.05). At shorter wavelength irradiances (400nm), a reduction in mitochondrial activity was detected although not significant, whereas longer wavelength irradiances (at 633, 656, 781 and 799nm) significantly increased mitochondrial activity (P<0.05) in DPCs. At these wavelengths, mitochondrial activity was generally increased for exposures less than 90s with 30s exposures being most effective with 24h incubation. Increasing the post-irradiation incubation period increased the measured response and identified further significance (P<0.05). The biological responses of human DPCs were wavelength, exposure-time and incubation period dependent. The optimisation of irradiation parameters will be key to the successful application of LLLT in dentistry.

[Changes of telemetry electrical activity in the infralimbic cortex of morphine-dependent rats with extinguished drug-seeking behavior].

PubMed

Li, Jing; Pan, Qunwan; Zhu, Zaiman; Li, Min; Bai, Yu; Yu, Ran

2015-05-01

To investigate the changes of telemetry electrical activity in the infralimbic cortex (IL) of morphine-dependent rats with extinguished drug-seeking behavior. SD rats were randomly divided into model group and control group and received operations of brain stereotaxic electrode embedding in the IL. The rats in the model group were induced to acquire morphine dependence and then received subsequent extinction training, and the changes of electrical activity in the IL were recorded with a physical wireless telemetry system. In rats with morphine dependence, the time staying in the white box was significantly longer on days 1 and 2 after withdrawal than that before morphine injection and that of the control rats, but was obviously reduced on days 1 and 2 after extinction training to the control level. Compared with the control group, the morphine-dependent rats on day 2 following withdrawal showed significantly increased β wave and decreased δ wave when they stayed in the white box but significantly increased δ wave and decreased α wave and β wave when they shuttled from the black to the white box. On day 2 of extinction, the model rats, when staying in the white box, showed significantly decreased θ wave compared with that of the control rats group but decreased β wave and θ wave and increased δ wave compared with those in the withdrawal period. When they shuttled from black to white box, the model rats showed decreased δ wave and increased α wave and β wave compared with those in the withdrawal period. Morphine-dependent rats have abnormal changes of electrical activity in the IL in drug-seeking extinction to affect their drug-seeking motive and inhibit the expression and maintenance of drug-seeking behaviors.

Specimen charging in X-ray absorption spectroscopy: correction of total electron yield data from stabilized zirconia in the energy range 250-915 eV.

PubMed

Vlachos, Dimitrios; Craven, Alan J; McComb, David W

2005-03-01

The effects of specimen charging on X-ray absorption spectroscopy using total electron yield have been investigated using powder samples of zirconia stabilized by a range of oxides. The stabilized zirconia powder was mixed with graphite to minimize the charging but significant modifications of the intensities of features in the X-ray absorption near-edge fine structure (XANES) still occurred. The time dependence of the charging was measured experimentally using a time scan, and an algorithm was developed to use this measured time dependence to correct the effects of the charging. The algorithm assumes that the system approaches the equilibrium state by an exponential decay. The corrected XANES show improved agreement with the electron energy-loss near-edge fine structure obtained from the same samples.

Fibrinolytic activity and dose-dependent effect of incubating human blood clots in caffeic acid phenethyl ester: in vitro assays.

PubMed

Elnager, Abuzar; Hassan, Rosline; Idris, Zamzuri; Mustafa, Zulkifli; Wan-Arfah, Nadiah; Sulaiman, S A; Gan, Siew Hua; Abdullah, Wan Zaidah

2015-01-01

Background. Caffeic acid phenethyl ester (CAPE) has been reported to possess time-dependent fibrinolytic activity by in vitro assay. This study is aimed at investigating fibrinolytic dose-dependent activity of CAPE using in vitro assays. Methods. Standardized human whole blood (WB) clots were incubated in either blank controls or different concentrations of CAPE (3.75, 7.50, 15.00, 22.50, and 30.00 mM). After 3 hours, D-dimer (DD) levels and WB clot weights were measured for each concentration. Thromboelastography (TEG) parameters were recorded following CAPE incubation, and fibrin morphology was examined under a confocal microscope. Results. Overall, mean DD (μg/mL) levels were significantly different across samples incubated with different CAPE concentrations, and the median pre- and postincubation WB clot weights (grams) were significantly decreased for each CAPE concentration. Fibrin removal was observed microscopically and indicated dose-dependent effects. Based on the TEG test, the Ly30 fibrinolytic parameter was significantly different between samples incubated with two different CAPE concentrations (15.0 and 22.50 mM). The 50% effective dose (ED50) of CAPE (based on DD) was 1.99 mg/mL. Conclusions. This study suggests that CAPE possesses fibrinolytic activity following in vitro incubation and that it has dose-dependent activities. Therefore, further investigation into CAPE as a potential alternative thrombolytic agent should be conducted.

Assessing dimensions of nicotine dependence

PubMed Central

Piper, Megan E.; McCarthy, Danielle E.; Bolt, Daniel M.; Smith, Stevens S.; Lerman, Caryn; Benowitz, Neal; Fiore, Michael C.; Baker, Timothy B.

2008-01-01

Considerable research, ranging from survey to clinical to genetic, has utilized traditional measures of tobacco dependence, such as the Fagerstrom Test of Nicotine Dependence (FTND) and the Diagnostic and Statistical Manual (DSM-IV) criteria, that focus on endpoint definitions of tobacco dependence such as heavy smoking, time to first cigarette in the morning, and smoking despite consequences. In an effort to better understand possible theories and mechanisms underlying tobacco dependence, which could be used to improve treatment and research, two multidimensional measures of tobacco dependence have been developed: the Nicotine Dependence Syndrome Scale (NDSS) and the Wisconsin Inventory of Smoking Dependence Motives (WISDM). This research used data from three randomized smoking cessation trials to examine the internal consistency and validity (convergent, concurrent and predictive) of these scales, relative to each other and the traditional measures. Results reveal that NDSS and WISDM subscales are related to important dependence criteria, but in a heterogeneous fashion. The data suggest that there are important underlying mechanisms or motives that are significantly related to different important outcomes, such as withdrawal and cessation. The FTND was most strongly related to abstinence at 1 week and 6 months post-quit, whereas the WISDM Tolerance subscale was most strongly related to abstinence at the end of treatment. The NDSS Priority subscale was consistently predictive of outcome at all three follow-up time points. There is also evidence that WISDM subscales are related to a biomarker of the rate of nicotine metabolism. PMID:18584464

Time-dependent alteration in cromakalim-induced relaxation of corpus cavernosum from streptozocin-induced diabetic rats.

PubMed

Ghasemi, Mehdi; Sadeghipour, Hamed; Asadi, Shahrzad; Dehpour, Ahmad Reza

2007-09-01

The purpose of the present study was to investigate the relaxant responses to the ATP-sensitive potassium (K(ATP)) channel opener cromakalim in corpus cavernosum strips from 1-, 2-, 4-, 6-, and 8-week streptozocin-induced diabetic rats. Cromakalim (1 nM-0.1 mM) produced concentration-dependent relaxation in phenylephrine (7.5 microM)-precontracted isolated rat corporal strips. Compared with age-matched control animals, a significant enhancement in cromakalim-induced relaxation of corpus cavernosum was observed in 2-week diabetic animals, whereas the relaxant responses to cromakalim were decreased in 6-and 8-week diabetic animals. However, the cromakalim-induced relaxation was not altered in either 1-week or 4-week rat corporal strips in comparison with corresponding age-matched non-diabetic groups. Preincubation with the K(ATP) channel blocker glibenclamide (10 microM) significantly inhibited the cromakalim-induced relaxation in both non-diabetic and diabetic rat corpus cavernosum, but neither the voltage-dependent K(+) channel (K(V)) antagonist 4-aminopyridine (1 mM) nor the calcium-activated K(+) channel (K(Ca)) antagonist charybdotoxin (0.1 microM) had significant effect on cromakalim-induced relaxation in both control and diabetic rat corporal strips. Relaxation responses to the nitric oxide donor sodium nitroprusside (1 nM-0.1 mM) in diabetic rat corpus cavernosum were similar to that of age-matched controls. These data demonstrated that the relaxant responses to cromakalim were altered in diabetic cavernosal strips in a time dependent manner, suggesting that the period of diabetes mellitus may play a key role in the K(ATP) channels function in rat corpus cavernosum.

[Site of prelingual cochlear stimulation and its effect on electrically evoked compound action potentials and refractory using the Nucleus 24 standard].

PubMed

Ma, R Y; Li, W; Jiang, X J

2016-12-01

Objective: To investigate the correlation between the site of prelingual cochlear stimulation and its effect on electrically evoked compound action potentials. Method: Recordings of auditory nerve responses were conducted in 32 prelingual subjects to demonstrate the feasibility of ECAP recordings using the nerve response telemetry(NRT) feature of the Nucleus CI24R(CA) system software. These recordings were then analyzed based on the site of cochlear stimulation defined as basal, middle and apical to determine if the amplitude, threshold and slope of the amplitude growth function and the refractory time differs depending on the region of stimulation. Result: Findings of our prelingual children showed significant differences in the ECAP recordings depending on the stimulation site. Comparing the apical with the basal region, on average higher amplitudes, lower thresholds and steeper slopes of the amplitude growth function hadbeen observed. The refractory time showed an overall dependence on cochlear region; however post-hoc tests showed no significant effect between individual regions. Conclusion: Obtaining ECAP recordings is also possible in the most apical region of the cochlea. However, differences can be observed depending on the region of the cochlea stimulated. Specifically, significant higher ECAP amplitude, lower thresholds and steeper amplitude growth function slopes have been observed in the apical region. These differences between prelingual children and adults could be explained by the location of the stimulating electrode with respect to the neural tissue in the cochlea, a higher density, or an increased neural survival rate of neural tissue in the apex. Copyright© by the Editorial Department of Journal of Clinical Otorhinolaryngology Head and Neck Surgery.

Top-level dynamics and the regulated gene response of feed-forward loop transcriptional motifs.

PubMed

Mayo, Michael; Abdelzaher, Ahmed; Perkins, Edward J; Ghosh, Preetam

2014-09-01

Feed-forward loops are hierarchical three-node transcriptional subnetworks, wherein a top-level protein regulates the activity of a target gene via two paths: a direct-regulatory path, and an indirect route, whereby the top-level proteins act implicitly through an intermediate transcription factor. Using a transcriptional network of the model bacterium Escherichia coli, we confirmed that nearly all types of feed-forward loop were significantly overrepresented in the bacterial network. We then used mathematical modeling to study their dynamics by manipulating the rise times of the top-level protein concentration, termed the induction time, through alteration of the protein destruction rates. Rise times of the regulated proteins exhibited two qualitatively different regimes, depending on whether top-level inductions were "fast" or "slow." In the fast regime, rise times were nearly independent of rapid top-level inductions, indicative of biological robustness, and occurred when RNA production rate-limits the protein yield. Alternatively, the protein rise times were dependent upon slower top-level inductions, greater than approximately one bacterial cell cycle. An equation is given for this crossover, which depends upon three parameters of the direct-regulatory path: transcriptional cooperation at the DNA-binding site, a protein-DNA dissociation constant, and the relative magnitude of the top-level protien concentration.

Software Aids Visualization of Computed Unsteady Flow

NASA Technical Reports Server (NTRS)

Kao, David; Kenwright, David

2003-01-01

Unsteady Flow Analysis Toolkit (UFAT) is a computer program that synthesizes motions of time-dependent flows represented by very large sets of data generated in computational fluid dynamics simulations. Prior to the development of UFAT, it was necessary to rely on static, single-snapshot depictions of time-dependent flows generated by flow-visualization software designed for steady flows. Whereas it typically takes weeks to analyze the results of a largescale unsteady-flow simulation by use of steady-flow visualization software, the analysis time is reduced to hours when UFAT is used. UFAT can be used to generate graphical objects of flow visualization results using multi-block curvilinear grids in the format of a previously developed NASA data-visualization program, PLOT3D. These graphical objects can be rendered using FAST, another popular flow visualization software developed at NASA. Flow-visualization techniques that can be exploited by use of UFAT include time-dependent tracking of particles, detection of vortex cores, extractions of stream ribbons and surfaces, and tetrahedral decomposition for optimal particle tracking. Unique computational features of UFAT include capabilities for automatic (batch) processing, restart, memory mapping, and parallel processing. These capabilities significantly reduce analysis time and storage requirements, relative to those of prior flow-visualization software. UFAT can be executed on a variety of supercomputers.

The effect of locally delivered recombinant human bone morphogenetic protein-2 with hydroxyapatite/tri-calcium phosphate on the biomechanical properties of bone in diabetes-related osteoporosis.

PubMed

Liporace, Frank A; Breitbart, Eric A; Yoon, Richard S; Doyle, Erin; Paglia, David N; Lin, Sheldon

2015-06-01

Recombinant human bone morphogenetic protein-2 (rhBMP-2) is particularly effective in improving osteogenesis in patients with diminished bone healing capabilities, such as individuals with type 1 diabetes mellitus (T1DM) who have impaired bone healing capabilities and increased risk of developing osteoporosis. This study measured the effects of rhBMP-2 treatment on osteogenesis by observing the dose-dependent effect of localized delivery of rhBMP-2 on biomechanical parameters of bone using a hydroxyapatite/tri-calcium phosphate (HA/TCP) carrier in a T1DM-related osteoporosis animal model. Two different doses of rhBMP-2 (LD low dose, HD high dose) with a HA/TCP carrier were injected into the femoral intramedullary canal of rats with T1DM-related osteoporosis. Two more diabetic rat groups were injected with saline alone and with HA/TCP carrier alone. Radiographs and micro-computed tomography were utilized for qualitative assessment of bone mineral density (BMD). Biomechanical testing occurred at 4- and 8-week time points; parameters tested included torque to failure, torsional rigidity, shear stress, and shear modulus. At the 4-week time point, the LD and HD groups both exhibited significantly higher BMD than controls; at the 8-week time point, the HD group exhibited significantly higher BMD than controls. Biomechanical testing revealed dose-dependent, higher trends in all parameters tested at the 4- and 8-week time points, with minimal significant differences. Groups treated with rhBMP-2 demonstrated improved bone mineral density at both 4 and 8 weeks compared to control saline groups, in addition to strong trends towards improvement of intrinsic and extrinsic biomechanical properties when compared to control groups. Data revealed trends toward dose-dependent increases in peak torque, torsional rigidity, shear stress, and shear modulus 4 weeks after rhBMP-2 treatment. Not applicable.

Duration-dependent effects of clinically relevant oral alendronate doses on cortical bone toughness in beagle dogs

PubMed Central

Burr, David B.; Liu, Ziyue; Allen, Matthew R.

2014-01-01

Bisphosphonates (BPs) have been shown to significantly reduce bone toughness in vertebrae within one year when given at clinical doses to dogs. Although BPs also reduce toughness in cortical bone when given at high doses, their effect on cortical bone material properties when given at clinical doses is less clear. In part, this may be due to the use of small sample sizes that were powered to demonstrate differences in bone mineral density rather than bone’s material properties. Our lab has conducted several studies in which dogs were treated with alendronate at a clinically relevant dose. The goal of this study was to examine these published and unpublished data collectively to determine whether there is a significant time-dependent effect of alendronate on toughness of cortical bone. This analysis seemed particularly relevant given the recent occurrence of atypical femoral fractures in humans. Differences in the toughness of ribs taken from dogs derived from five separate experiments were measured. The dogs were orally administered saline (CON, 1 ml/kg/day) or alendronate (ALN) at a clinical dose (0.2 mg/kg/day). Treatment duration ranged from 3 months to 3 years. Groups were compared using ANOVA, and time trends analyzed with linear regression analysis. Linear regressions of the percent difference in toughness between CON and ALN at each time point revealed a significant reduction in toughness with longer exposure to ALN. The downward trend was primarily driven by a downward trend in post-yield toughness, whereas toughness in the pre-yield region was not changed relative to CON. These data suggest that a longer duration of treatment with clinical doses of ALN results in deterioration of cortical bone toughness in a time-dependent manner. As the duration of treatment is lengthened, the cortical bone exhibits increasingly brittle behavior. This may be important in assessing the role that long-term BP treatments play in the risk of atypical fractures of femoral cortical bone in humans. PMID:25445446

Postinfection activity, residue levels, and persistence of azoxystrobin, fludioxonil, and pyrimethanil applied alone or in combination with heat and imazalil for green mold control on inoculated oranges.

PubMed

Schirra, Mario; Palma, Amedeo; Barberis, Antonio; Angioni, Alberto; Garau, Vincenzo Luigi; Cabras, Paolo; D'Aquino, Salvatore

2010-03-24

The postinfection activity of azoxystrobin (AZX), fludioxonil (FLU), and pyrimethanil (PYR), applied alone or in combination with imazalil (IMZ), in controlling postharvest green mold in 'Salustiana' oranges inoculated with Penicillium digitatum was studied. Fruits were immersed for 30 or 60 s in (i) water or water mixtures at 20 degrees C containing AZX, FLU, or PYR at 600 mg/L; and (ii) IMZ at 600 mg/L, alone or in combination with AZX, FLU, or PYR at 600 mg/L. Similar treatments were performed at 50 degrees C using the active ingredients at half rates with respect to the treatments at 20 degrees C. Fungicide residues in fruits were analyzed following treatments and after 14 days of simulated shelf life at 17 degrees C. AZX or FLU mixtures at 20 degrees C for 30-60 s similarly but moderately reduced green mold decay with respect to control fruit; differences due to dip time were not significant. Superior control of decay was achieved by PYR and, especially, IMZ, applied alone or in combination with AZX, FLU, or PYR. The activity of PYR at 20 degrees C was significantly dependent on treatment time, whereas that of IMZ and combined treatments at 20 degrees C was not. The effectiveness of FLU or PYR mixtures at 50 degrees C in controlling decay was similar and superior to that of AZX. The action of single- or double-fungicide application was not dependent on dip time in most samples. IMZ or combined mixtures at 50 degrees C were consistently more effective with respect to single-fungicide treatments with AZX, FLU, or PYR. The application of heated fungicide mixtures resulted in significantly higher residue accumulation in most fruit samples compared to treatments performed at 20 degrees C. The degradation rate of fungicides was generally low and dependent on treatment conditions such as time, temperature, and the presence or not of other fungicides.

Dependence of long-term persistence properties of precipitation on spatial and regional characteristics

NASA Astrophysics Data System (ADS)

Tyralis, Hristos; Dimitriadis, Panayiotis; Iliopoulou, Theano; Tzouka, Katerina; Koutsoyiannis, Demetris

2017-04-01

The long-term persistence (LTP), else known in hydrological science as the Hurst phenomenon, is a behaviour observed in geophysical processes in which wet years or dry years are clustered to respective long time periods. A common practice for evaluating the presence of the LTP is to model the geophysical time series with the Hurst-Kolmogorov process (HKp) and estimate its Hurst parameter H where high values of H indicate strong LTP. We estimate H of the mean annual precipitation using instrumental data from approximately 1 500 stations which cover a big area of the earth's surface and span from 1916 to 2015. We regress the H estimates of all stations on their spatial and regional characteristics (i.e. their location, elevation and Köppen-Geiger climate class) using a random forest algorithm. Furthermore, we apply the Mann-Kendall test under the LTP assumption (MKt-LTP) to all time series to assess the significance of observed trends of the mean annual precipitation. To summarize the results, the LTP seems to depend mostly on the location of the stations, while the predictive value of the fitted regression model is good. Thus when investigating for LTP properties we recommend that the local characteristics should be considered. Additionally, the application of the MKt-LTP suggests that no significant monotonic trend can characterize the global precipitation. Dominant positive significant trends are observed mostly in main climate type D (snow), while in the other climate types the percentage of stations with positive significant trends was approximately equal to that of negative significant trends. Furthermore, 50% of all stations do not exhibit significant trends at all.

Relations between acoustic cavitation and skin resistance during intermediate- and high-frequency sonophoresis.

PubMed

Rich, Kyle T; Hoerig, Cameron L; Rao, Marepalli B; Mast, T Douglas

2014-11-28

Enhanced skin permeability is known to be achieved during sonophoresis due to ultrasound-induced cavitation. However, the mechanistic role of cavitation during sonophoresis has been extensively investigated only for low-frequency (LFS, <100 kHz) applications. Here, mechanisms of permeability-enhancing stable and inertial cavitation were investigated by passively monitoring subharmonic and broadband emissions arising from cavitation isolated within or external to porcine skin in vitro during intermediate- (IFS, 100-700 kHz) and high-frequency sonophoresis (HFS, >1 MHz). The electrical resistance of skin, a surrogate measure of the permeability of skin to a variety of compounds, was measured to quantify the reduction and subsequent recovery of the skin barrier during and after exposure to pulsed (1 second pulse, 20% duty cycle) 0.41 and 2.0 MHz ultrasound over a range of acoustic powers (0-21.7 W) for 30 min. During IFS, significant skin resistance reductions and acoustic emissions from cavitation were measured exclusively when cavitation was isolated outside of the skin. Time-dependent skin resistance reductions measured during IFS correlated significantly with subharmonic and broadband emission levels. During HFS, significant skin resistance reductions were accompanied by significant acoustic emissions from cavitation measured during trials that isolated cavitation activity either outside of skin or within skin. Time-dependent skin resistance reductions measured during HFS correlated significantly greater with subharmonic than with broadband emission levels. The reduction of the skin barrier due to sonophoresis was reversible in all trials; however, effects incurred during IFS recovered more slowly and persisted over a longer period of time than HFS. These results quantitatively demonstrate the significance of cavitation during sonophoresis and suggest that the mechanisms and post-treatment longevity of permeability enhancement due to IFS and HFS treatments are different. Copyright © 2014 Elsevier B.V. All rights reserved.

Studies in interactive communication. I - The effects of four communication modes on the behavior of teams during cooperative problem-solving.

NASA Technical Reports Server (NTRS)

Chapanis, A.; Ochsman, R. B.; Parrish, R. N.; Weeks, G. D.

1972-01-01

Two-man teams solved credible, 'real-world' problems for which computer assistance has been or could be useful. Conversations were carried on in one of four modes of communication: (1) typewriting, (2) handwriting, (3) voice, and (4) natural, unrestricted communication. Two groups of subjects (experienced and inexperienced typists) were tested in the typewriting mode. Performance was assessed on three classes of dependent measures: time to solution, behavioral measures of activity, and linguistic measures. Significant and meaningful differences among the communication modes were found in each of the three classes of dependent variable. This paper is concerned mainly with the results of the activity analyses. Behavior was recorded in 15 different categories. The analyses of variance yielded 34 statistically significant terms of which 27 were judged to be practically significant as well. When the data were transformed to eliminate heterogeneity, the analyses of variance yielded 35 statistically significant terms of which 26 were judged to be practically significant.

[Effect of flooding time length on mycorrhizal colonization of three AM fungi in two wetland plants].

PubMed

Ma, Lei-Meng; Wang, Peng-Teng; Wang, Shu-Guang

2014-01-01

In order to provide information for elucidating effect of flooding on the formation and function of AM in wetland plants, three AM fungi (Glomus intraradices, Glomus versiforme, Glomus etunicatum) were used to investigate the effects of flooding time length on their colonization in cattail (Typha orientalis) and rice (Oryza sativa L. ). The results showed that the mycorrhizal colonization rate (MCR) presented downtrend with increasing flooding time length. In cattail, MCR of the fungus F3 was higher than those of fungi F1 and F2, but no significant difference in MCR was found between fungi F1 and F2. In rice, the MCRs of fungi F2 and F3 were higher than that of E1. In both plants, the proportional frequency of hyphae was the highest while the proportional frequency of arbuscules and vesicles was very low in all treatments, indicating that hyphal colonization was the main route for AM formation. The proportional frequency of hyphae in cattail increased with the flooding time length, but no significant trend was observed in rice plant. The proportional frequency of arhuscules decreased with the increase of flooding time, and was the highest in the treatment without flooding (treatment IV). The number of spores produced by AM fungi increased with increasing flooding time, and reached the highest in the treatment of long time flooding (treatment I). In the same treatment, the fungus F3 produced more spores than fungi F1 and F2. Changes in wet weight of the two plants showed that AM could increase cattail growth under flooding, hut little effect on rice growth was found. It is concluded that flooding time length significantly affected the mycorrhizal colonization rate and the proportional frequency of colonization. AM could enhance the growth of wetland plant, but this depends on the mycorrhizal dependence of host plant on AM fungi. Therefore, flooding time length should be considered in the inoculation of wetland plants with AM fungi.

Assessment of time-dependent density functional theory with the restricted excitation space approximation for excited state calculations of large systems

NASA Astrophysics Data System (ADS)

Hanson-Heine, Magnus W. D.; George, Michael W.; Besley, Nicholas A.

2018-06-01

The restricted excitation subspace approximation is explored as a basis to reduce the memory storage required in linear response time-dependent density functional theory (TDDFT) calculations within the Tamm-Dancoff approximation. It is shown that excluding the core orbitals and up to 70% of the virtual orbitals in the construction of the excitation subspace does not result in significant changes in computed UV/vis spectra for large molecules. The reduced size of the excitation subspace greatly reduces the size of the subspace vectors that need to be stored when using the Davidson procedure to determine the eigenvalues of the TDDFT equations. Furthermore, additional screening of the two-electron integrals in combination with a reduction in the size of the numerical integration grid used in the TDDFT calculation leads to significant computational savings. The use of these approximations represents a simple approach to extend TDDFT to the study of large systems and make the calculations increasingly tractable using modest computing resources.

Nonlinear bivariate dependency of price-volume relationships in agricultural commodity futures markets: A perspective from Multifractal Detrended Cross-Correlation Analysis

NASA Astrophysics Data System (ADS)

He, Ling-Yun; Chen, Shu-Peng

2011-01-01

Nonlinear dependency between characteristic financial and commodity market quantities (variables) is crucially important, especially between trading volume and market price. Studies on nonlinear dependency between price and volume can provide practical insights into market trading characteristics, as well as the theoretical understanding of market dynamics. Actually, nonlinear dependency and its underlying dynamical mechanisms between price and volume can help researchers and technical analysts in understanding the market dynamics by integrating the market variables, instead of investigating them in the current literature. Therefore, for investigating nonlinear dependency of price-volume relationships in agricultural commodity futures markets in China and the US, we perform a new statistical test to detect cross-correlations and apply a new methodology called Multifractal Detrended Cross-Correlation Analysis (MF-DCCA), which is an efficient algorithm to analyze two spatially or temporally correlated time series. We discuss theoretically the relationship between the bivariate cross-correlation exponent and the generalized Hurst exponents for time series of respective variables. We also perform an empirical study and find that there exists a power-law cross-correlation between them, and that multifractal features are significant in all the analyzed agricultural commodity futures markets.

Quasar Astrophysics with the Space Interferometry Mission

NASA Technical Reports Server (NTRS)

Unwin, Stephen; Wehrle, Ann; Meier, David; Jones, Dayton; Piner, Glenn

2007-01-01

Optical astrometry of quasars and active galaxies can provide key information on the spatial distribution and variability of emission in compact nuclei. The Space Interferometry Mission (SIM PlanetQuest) will have the sensitivity to measure a significant number of quasar positions at the microarcsecond level. SIM will be very sensitive to astrometric shifts for objects as faint as V = 19. A variety of AGN phenomena are expected to be visible to SIM on these scales, including time and spectral dependence in position offsets between accretion disk and jet emission. These represent unique data on the spatial distribution and time dependence of quasar emission. It will also probe the use of quasar nuclei as fundamental astrometric references. Comparisons between the time-dependent optical photocenter position and VLBI radio images will provide further insight into the jet emission mechanism. Observations will be tailored to each specific target and science question. SIM will be able to distinguish spatially between jet and accretion disk emission; and it can observe the cores of galaxies potentially harboring binary supermassive black holes resulting from mergers.

Profiling of Kidney Injury Biomarkers in Patients Receiving Cisplatin: Time-Dependent Changes in the Absence of Clinical Nephrotoxicity

PubMed Central

George, Blessy; Wen, Xia; Mercke, Nickie; Gomez, Madeleine; O’Bryant, Cindy; Bowles, Daniel W.; Hu, Yichun; Hogan, Susan L.

2016-01-01

The success of cisplatin-containing regimens to treat solid tumors is limited, in part, by nephrotoxicity. In rodents, several urinary proteins have emerged as more sensitive indicators of cisplatin-induced kidney injury. We sought to characterize time-dependent changes in the urinary concentrations of 12 proteins including KIM-1, calbindin, β2M, and TFF3 after cisplatin therapy. Urine was collected at baseline, 3 (range: 2-5), and 10 (range: 9-11) days from 57 patients with solid tumors receiving outpatient cisplatin therapy (≥ 25 mg/m2). Serum creatinine was largely unchanged after cisplatin infusion. However, compared to baseline values, several novel biomarkers were significantly increased in the urine including β2M, which was 3-fold higher by day 3 (p<0.0001). Urinary KIM-1 and TFF3 were elevated 2-fold by day 10 (p=0.002 and p=0.002, respectively) whereas calbindin levels were increased 8-fold (p<0.0001). We report novel time-dependent changes in the urinary excretion of noninvasive markers of subclinical kidney injury after cisplatin treatment. PMID:28002630

Prospective Memory in HIV-associated Neurocognitive Disorders (HAND): The Neuropsychological Dynamics of Time Monitoring

PubMed Central

Doyle, Katie L.; Loft, Shayne; Morgan, Erin E.; Weber, Erica; Cushman, Clint; Johnston, Elaine; Grant, Igor; Woods, Steven Paul

2013-01-01

Strategic monitoring during a delay interval is theorized to be an essential feature of time-based prospective memory (TB PM), the cognitive architecture of which is thought to rely heavily on frontostriatal systems and executive functions. This hypothesis was examined in 55 individuals with HIV-associated neurocognitive disorders (HAND) and 108 seronegative comparison participants who were administered the Memory for Intentions Screening Test (MIST), during which time monitoring (clock checking) behavior was measured. Results revealed a significant interaction between HAND group and the frequency of clock checking, in which individuals with HAND monitored checked the clock significantly less often than the comparison group across the TB PM retention intervals of the MIST. Subsequent analyses in the HAND sample revealed that the frequency of clocking checking was positively related to overall TB performance, as well as to standard clinical measures of retrospective memory and verbal fluency. These findings add support to a growing body of research elucidating TB PM’s reliance on strategic monitoring processes dependent upon intact frontostriatal systems. HIV-associated TB strategic time monitoring deficits may manifest in poorer functioning outcomes, including medication non-adherence and dependence in activities of daily living. Future research is needed to further delineate the cognitive mechanisms underlying strategic time monitoring in order to advise rehabilitation strategies for reducing HAND related TB PM deficits. PMID:23465043

Optical characterization of shock-induced chemistry in the explosive nitromethane using DFT and time-dependent DFT

NASA Astrophysics Data System (ADS)

Pellouchoud, Lenson; Reed, Evan

2014-03-01

With continual improvements in ultrafast optical spectroscopy and new multi-scale methods for simulating chemistry for hundreds of picoseconds, the opportunity is beginning to exist to connect experiments with simulations on the same timescale. We compute the optical properties of the liquid phase energetic material nitromethane (CH3NO2) for the first 100 picoseconds behind the front of a simulated shock at 6.5km/s, close to the experimentally observed detonation shock speed. We utilize molecular dynamics trajectories computed using the multi-scale shock technique (MSST) for time-resolved optical spectrum calculations based on both linear response time-dependent DFT (TDDFT) and the Kubo-Greenwood (KG) formula within Kohn-Sham DFT. We find that TDDFT predicts optical conductivities 25-35% lower than KG-based values and provides better agreement with the experimentally measured index of refraction of unreacted nitromethane. We investigate the influence of electronic temperature on the KG spectra and find no significant effect at optical wavelengths. With all methods, the spectra evolve non-monotonically in time as shock-induced chemistry takes place. We attribute the time-resolved absorption at optical wavelengths to time-dependent populations of molecular decomposition products, including NO, CNO, CNOH, H2O, and larger molecules. Supported by NASA Space Technology Research Fellowship (NSTRF) #NNX12AM48H.

Acute toxicity of some synthetic cyanogens in rats: time-dependent cyanide generation and cytochrome oxidase inhibition in soft tissues after sub-lethal oral intoxication.

PubMed

Rao, Pooja; Singh, Poonam; Yadav, Shiv Kumar; Gujar, Niranjan L; Bhattacharya, Rahul

2013-09-01

Cyanogens include complex nitrile-containing compounds that can generate free cyanide of toxicological significance. Acute toxicity, time-dependent cyanide generation and cytochrome oxidase (CYTOX) inhibition in soft tissues, and urinary thiocyanate levels were measured after acute cyanogen intoxication in rats. Order of cyanogens in terms of LD₅₀ was: malononitrile (MCN)>propionitrile (PCN)≈sodium nitroprusside (SNP)>acrylonitrile (ACN)>succinonitrile (SCN)>acetonitrile (ATCN) for oral, and SNP>MCN>ACN>PCN>SCN>ATCN for intraperitoneal and subcutaneous routes. MCN was most toxic by oral (LD₅₀=66.4 mg/kg) and SNP by intraperitoneal (LD₅₀=16.7 mg/kg) and subcutaneous (LD₅₀=11.9 mg/kg) routes. Minimum survival time (25 min) was recorded after 4.0 LD₅₀ ATCN. Order of cyanogens (0.75 LD₅₀; oral) on the basis of maximum blood cyanide and time of peak cyanide generation were: ATCN>SNP>SCN>PCN>MCN>ACN, and MCN (30 min)

Age influences the effects of nicotine and monoamine oxidase inhibition on mood-related behaviors in rats.

PubMed

Villégier, Anne-Sophie; Gallager, Brittney; Heston, Jon; Belluzzi, James D; Leslie, Frances M

2010-03-01

Epidemiological studies have demonstrated a comorbidity of smoking with depression and anxiety, particularly during adolescence. However, few animal studies have considered possible synergistic interactions between nicotine and other tobacco smoke constituents, such as monoamine oxidase (MAO) inhibitors, in the regulation of mood. The aim of the study was to test the hypothesis that nicotine combined with the irreversible MAO inhibitor, tranylcypromine, will differentially affect depression- and anxiety-related behaviors in adolescent and adult rats. Nicotine (0, 0.05, 0.2 mg/kg, s.c.) and tranylcypromine (3 mg/kg, i.p.) were tested separately, or together, on male rats aged postnatal days 30 and 68, in three mood-related behavioral tests: forced swim test (FST), elevated plus maze (EPM), and open field. Nicotine (0.2 mg/kg) in adults significantly decreased floating time in the FST and increased time spent in the open arm of the EPM, with no change in locomotor activity. Tranylcypromine pretreatment combined with nicotine (0.2 mg/kg) significantly increased locomotor activity and time spent in the center of the open field. Whereas nicotine alone had no significant effect on adolescents, it significantly increased locomotor activity and decreased floating time in the FST when combined with tranylcypromine pretreatment. There is an age-dependent effect of nicotine, alone and in combination with MAO inhibition, on mood-related behaviors. Whereas nicotine alone induces mood improvement in adults, it has no effect on adolescents. Nicotine combined with tranylcypromine has unique, age-dependent effects. Thus, experimental studies of smoking should consider both age and other tobacco constituents, such as MAO inhibitors, as critical factors.

The Salivary β-HEX A% Index as an Excellent Marker of Periodontitis in Smoking Alcohol-Dependent Persons

PubMed Central

Waszkiewicz, Napoleon; Zalewska-Szajda, Beata; Chojnowska, Sylwia; Szajda, Sławomir Dariusz; Zalewska, Anna; Konarzewska, Beata; Szulc, Agata; Wojtulewska-Supron, Aleksandra; Kępka, Alina; Knaś, Małgorzata; Ładny, Jerzy Robert; Milewski, Robert; Zwierz, Krzysztof

2013-01-01

Background. Severe periodontitis leading to tooth loss is found in 5–15% of most populations worldwide. Aim. The applicability of salivary β-hexosaminidase (β-HEX A%, percentage of β-HEX A isoenzyme to total β-HEX) and β-HEX B% (β-HEX B/β-HEX) indexes was investigated as a possible marker of periodontitis. Methods. Thirty three alcohol-dependent smokers (AS) and 32 healthy controls (C) were enrolled in the study. The activity of β-HEX was measured spectrophotometrically. Results. β-HEX A% was significantly higher and β-HEX B% was lower in AS than in C group. We found a significant correlation between β-HEX A% and gingival index (GI) and an inverse correlation between β-HEX A% and salivary flow (SF), in all groups. Salivary β-HEX A% index in smoking alcoholics at 0.23 had excellent sensitivity (96%) and specificity (91%); the AUC for β-HEX A% was high (0.937). There were no correlations between amount/duration-time of alcohol drinking/smoking and β-HEX A% or β-HEX B%. We found significant correlations between the time period of denture wearing and GI, papilla bleeding index (PBI), and decayed missing filled teeth index (DMFT) and between GI and the amount of smoked cigarettes per day. Conclusion. Bad periodontal state was most likely due to the nicotine dependence. Salivary β-HEX A% is a promising excellent marker for the diagnosis of periodontitis. PMID:24288426

Drop-on-demand drop formation of polyethylene oxide solutions

NASA Astrophysics Data System (ADS)

Yan, Xuejia; Carr, Wallace W.; Dong, Hongming

2011-10-01

The dynamics of drop-on-demand (DOD) drop formation for solutions containing polyethylene oxide (PEO) have been studied experimentally. Using a piezoelectrical actuated inkjet printhead with the nozzle orifice diameter of 53 μm, experiments were conducted for a series of PEO aqueous solutions with molecular weights ranging from 14 to 1000 kg/mol, polydispersity from 1.02 to 2.5, and concentrations from 0.005 to 10 wt. %. The addition of a small amount of PEO can have a significant effect on the DOD drop formation process, increasing breakup time, decreasing primary drop speed, and decreasing the number of satellite drops in some cases. The effects depend on both molecular weight and concentration. At lower molecular weights (14 and 35 kg/mol), the effect of PEO over the dilute solution regime is insignificant even at concentrations large enough that the solution does not fall in the dilute regime. As PEO molecular weight increased, the effects became significant. For monodispersed PEO solutions, breakup time and primary drop speed closely correlated with effective relaxation time but not for polydispersed PEO. Effective relaxation time depended greatly on molecular weight distribution. Viscosity-average molecular weight, used in calculating effective relaxation time for polydispersed PEO solutions, did not adequately account for high molecular fractions in the molecular weight distribution of the polydispersed PEOs. A mixture rule was developed to calculate the effective relaxation times for aqueous solutions containing mixtures of monodispersed PEO, and breakup times and primary drop speeds correlated well with effective relaxation times. For our experiments, DOD drop formation was limited to Deborah number ≲ 23.

Associations of prodynorphin sequence variation with alcohol dependence and related traits are phenotype-specific and sex-dependent

PubMed Central

Winham, Stacey J.; Preuss, Ulrich W.; Geske, Jennifer R.; Zill, Peter; Heit, John A.; Bakalkin, Georgy; Biernacka, Joanna M.; Karpyak, Victor M.

2015-01-01

We previously demonstrated that prodynorphin (PDYN) haplotypes and single nucleotide polymorphism (SNP) rs2281285 are associated with alcohol dependence and the propensity to drink in negative emotional states, and recent studies suggest that PDYN gene effects on substance dependence risk may be sex-related. We examined sex-dependent associations of PDYN variation with alcohol dependence and related phenotypes, including negative craving, time until relapse after treatment and the length of sobriety episodes before seeking treatment, in discovery and validation cohorts of European ancestry. We found a significant haplotype-by-sex interaction (p  =  0.03), suggesting association with alcohol dependence in males (p = 1E-4) but not females. The rs2281285 G allele increased risk for alcohol dependence in males in the discovery cohort (OR = 1.49, p = 0.002), with a similar trend in the validation cohort (OR = 1.35, p = 0.086). However, rs2281285 showed a trend towards association with increased negative craving in females in both the discovery (beta = 10.16, p = 0.045) and validation samples (OR = 7.11, p = 0.066). In the discovery cohort, rs2281285 was associated with time until relapse after treatment in females (HR = 1.72, p = 0.037); in the validation cohort, it was associated with increased length of sobriety episodes before treatment in males (beta = 13.49, p = 0.001). Our findings suggest that sex-dependent effects of PDYN variants in alcohol dependence are phenotype-specific. PMID:26502829

Associations of prodynorphin sequence variation with alcohol dependence and related traits are phenotype-specific and sex-dependent.

PubMed

Winham, Stacey J; Preuss, Ulrich W; Geske, Jennifer R; Zill, Peter; Heit, John A; Bakalkin, Georgy; Biernacka, Joanna M; Karpyak, Victor M

2015-10-27

We previously demonstrated that prodynorphin (PDYN) haplotypes and single nucleotide polymorphism (SNP) rs2281285 are associated with alcohol dependence and the propensity to drink in negative emotional states, and recent studies suggest that PDYN gene effects on substance dependence risk may be sex-related. We examined sex-dependent associations of PDYN variation with alcohol dependence and related phenotypes, including negative craving, time until relapse after treatment and the length of sobriety episodes before seeking treatment, in discovery and validation cohorts of European ancestry. We found a significant haplotype-by-sex interaction (p  =  0.03), suggesting association with alcohol dependence in males (p = 1E-4) but not females. The rs2281285 G allele increased risk for alcohol dependence in males in the discovery cohort (OR = 1.49, p = 0.002), with a similar trend in the validation cohort (OR = 1.35, p = 0.086). However, rs2281285 showed a trend towards association with increased negative craving in females in both the discovery (beta = 10.16, p = 0.045) and validation samples (OR = 7.11, p = 0.066). In the discovery cohort, rs2281285 was associated with time until relapse after treatment in females (HR = 1.72, p = 0.037); in the validation cohort, it was associated with increased length of sobriety episodes before treatment in males (beta = 13.49, p = 0.001). Our findings suggest that sex-dependent effects of PDYN variants in alcohol dependence are phenotype-specific.

Covered interest parity arbitrage and temporal long-term dependence between the US dollar and the Yen

NASA Astrophysics Data System (ADS)

Batten, Jonathan A.; Szilagyi, Peter G.

2007-03-01

Using a daily time series from 1983 to 2005 of currency prices in spot and forward USD/Yen markets and matching equivalent maturity short-term US and Japanese interest rates, we investigate the sensitivity of the difference between actual prices in forward markets to those calculated from differentials in short-term interest rates. According to a fundamental theorem in financial economics termed covered interest parity (CIP), the actual and estimated prices should be identical once transaction and other costs are accommodated. The paper presents three important findings: first, we find evidence of considerable variation in CIP deviations from equilibrium; second, these deviations have diminished significantly and by 2000 have been almost eliminated; third, an analysis of the CIP deviations using the local Hurst exponent finds episodes of time-varying dependence over the various sample periods, which appear to be linked to episodes of dollar decline/Yen appreciation, or vice versa. The finding of temporal long-term dependence in CIP deviations is consistent with recent evidence of temporal long-term dependence in the returns of currency, stock and commodity markets.

Anti-Alzheimer activity of isolated karanjin from Pongamia pinnata (L.) pierre and embelin from Embelia ribes Burm.f.

PubMed

Saini, Prachi; Lakshmayya, L; Bisht, Vinod Singh

2017-01-01

The aim of this study is to find out the anti-Alzheimer's activity of isolated karanjin and embelin. Karanjin isolated from Pongamia pinnata (L.) pierre and embelin from Embelia ribes Burm.f. and their purity was confirmed by ultraviolet spectrophotometric and Thin layer chromatography based study. Anti-Alzheimer's activity of isolated compounds were evaluated through elevated plus maze and Morris water maze model on Swiss albino mice. Diazepam (1 mg/kg body weight, intraperitoneally) was used for the induction of Alzheimer's like effects (amnesia) on Swiss albino mice and piracetam (200 mg/kg body weight, oral) used as a standard treatment. In EPM, embelin and karanjin decrease the transfer latency time in dose dependent manner and escape latency time in MWM method. A significant ( P < 0.01) reduction in amnesia with an anti-Alzheimer's effect found when results of isolated compounds were compared with standard and vehicle control. Diazepam (1 mg/kg) treated group showed significant increase in escape latency and transfer latency when compared with vehicle control; which indicates impairment in learning and memory. Both isolated compounds and standard significantly reversed the amnesia induced by diazepam and improved learning and memory of mice in dose and time dependent manner. This study supports the ethnobotanical use of these two plants in India for the management of nerve or brain related problems.

Melanins as biomarkers of ovarian follicular atresia in the catfish Heteropneustes fossilis: biochemical and histochemical characterization, seasonal variation and hormone effects.

PubMed

Kumar, Ravi; Joy, Keerikkattil P

2015-06-01

Follicular atresia is a common feature of the vertebrate ovary that occurs at different stages of folliculogenesis and ovarian regression. It has physiological significance to maintain homeostasis and control fecundity, and ensure removal of post-ovulatory follicular remnants for preparing the ovary for the next cycle. Pigments appear late in the atretic process as indigestible waste formed out of the degradation of the oocytes, follicle wall and granulocytes. In the present study, pigment accumulation was demonstrated by Schmorl's and Perls' staining methods in the atretic ovarian follicles of Heteropneustes fossilis during follicular development and regression. Melanins were characterized spectrophotometrically for the first time in fish ovary. The predominant form is eumelanin, followed by pheomelanin and alkali-soluble melanin. Melanins showed significant seasonal variations with levels low in gonad resting phase, increasing to the peak in the post-spawning phase. The concentration of melanins increased time-dependently in post-ovulated ovary after human chorionic gonadotropin treatment. In the spawning phase, in vitro incubation of ovary slices with estradiol-17β or dexamethasone for 8 or 16 h decreased both eumelanin and pheomelanin levels time-dependently. The alkali-soluble melanin showed a significant decrease only in the dexamethasone group at 16 h. The results show that melanin assay can be used as a biomarker of follicular atresia in fish ovary, natural or induced by environmental toxicants.

Sexual reproduction, seeds, and seedlings

Treesearch

Walter T. McDonough

1985-01-01

Natural genetic interchange and extensive colonization of aspen by seed strongly depends upon favorable climatic and microclimatic conditions and upon human intervention. At times, in regions with the right combination of environmental conditions, there is significant L, reproduction by seed; elsewhere such establishment is rare. Seed production generally is profuse;...

Microrheology of highly crosslinked microtubule networks is dominated by force-induced crosslinker unbinding

PubMed Central

Yang, Yali; Bai, Mo; Klug, William S.; Levine, Alex J.

2012-01-01

We determine the time- and force-dependent viscoelastic responses of reconstituted networks of microtubules that have been strongly crosslinked by biotin-streptavidin bonds. To measure the microscale viscoelasticity of such networks, we use a magnetic tweezers device to apply localized forces. At short time scales, the networks respond nonlinearly to applied force, with stiffening at small forces, followed by a reduction in the stiffening response at high forces, which we attribute to the force-induced unbinding of crosslinks. At long time scales, force-induced bond unbinding leads to local network rearrangement and significant bead creep. Interestingly, the network retains its elastic modulus even under conditions of significant plastic flow, suggesting that crosslinker breakage is balanced by the formation of new bonds. To better understand this effect, we developed a finite element model of such a stiff filament network with labile crosslinkers obeying force-dependent Bell model unbinding dynamics. The coexistence of dissipation, due to bond breakage, and the elastic recovery of the network is possible because each filament has many crosslinkers. Recovery can occur as long as a sufficient number of the original crosslinkers are preserved under the loading period. When these remaining original crosslinkers are broken, plastic flow results. PMID:23577042

Outcomes following surgical management of femoral neck fractures in elderly dialysis-dependent patients.

PubMed

Puvanesarajah, Varun; Amin, Raj; Qureshi, Rabia; Shafiq, Babar; Stein, Ben; Hassanzadeh, Hamid; Yarboro, Seth

2018-06-01

Proximal femur fractures are one of the most common fractures observed in dialysis-dependent patients. Given the large comorbidity burden present in this patient population, more information is needed regarding post-operative outcomes. The goal of this study was to assess morbidity and mortality following operative fixation of femoral neck fractures in the dialysis-dependent elderly. The full set of medicare data from 2005 to 2014 was retrospectively analyzed. Elderly patients with femoral neck fractures were selected. Patients were stratified based on dialysis dependence. Post-operative morbidity and mortality outcomes were compared between the two populations. Adjusted odds were calculated to determine the effect of dialysis dependence on outcomes. A total of 320,629 patients met the inclusion criteria. Of dialysis-dependent patients, 1504 patients underwent internal fixation and 2662 underwent arthroplasty. For both surgical cohorts, dialysis dependence was found to be associated with at least 1.9 times greater odds of mortality within 1 and 2 years post-operatively. Blood transfusions within 90 days and infections within 2 years were significantly increased in the dialysis-dependent study cohort. Dialysis dependence alone did not contribute to increased mechanical failure or major medical complications. Regardless of the surgery performed, dialysis dependence is a significant risk factor for major post-surgical morbidity and mortality after operative treatment of femoral neck fractures in this population. Increased mechanical failure in the internal fixation group was not observed. The increased risk associated with caring for this population should be understood when considering surgical intervention and counseling patients.

Helioseismic Holography of Simulated Sunspots: dependence of the travel time on magnetic field strength and Wilson depression

PubMed Central

Felipe, T.; Braun, D. C.; Birch, A. C.

2018-01-01

Improving methods for determining the subsurface structure of sunspots from their seismic signature requires a better understanding of the interaction of waves with magnetic field concentrations. We aim to quantify the impact of changes in the internal structure of sunspots on local helioseismic signals. We have numerically simulated the propagation of a stochastic wave field through sunspot models with different properties, accounting for changes in the Wilson depression between 250 and 550 km and in the photospheric umbral magnetic field between 1500 and 3500 G. The results show that travel-time shifts at frequencies above approximately 3.50 mHz (depending on the phase-speed filter) are insensitive to the magnetic field strength. The travel time of these waves is determined exclusively by the Wilson depression and sound-speed perturbation. The travel time of waves with lower frequencies is affected by the direct effect of the magnetic field, although photospheric field strengths below 1500 G do not leave a significant trace on the travel-time measurements. These results could potentially be used to develop simplified travel-time inversion methods. PMID:29670298

Helioseismic Holography of Simulated Sunspots: dependence of the travel time on magnetic field strength and Wilson depression.

PubMed

Felipe, T; Braun, D C; Birch, A C

2017-01-01

Improving methods for determining the subsurface structure of sunspots from their seismic signature requires a better understanding of the interaction of waves with magnetic field concentrations. We aim to quantify the impact of changes in the internal structure of sunspots on local helioseismic signals. We have numerically simulated the propagation of a stochastic wave field through sunspot models with different properties, accounting for changes in the Wilson depression between 250 and 550 km and in the photospheric umbral magnetic field between 1500 and 3500 G. The results show that travel-time shifts at frequencies above approximately 3.50 mHz (depending on the phase-speed filter) are insensitive to the magnetic field strength. The travel time of these waves is determined exclusively by the Wilson depression and sound-speed perturbation. The travel time of waves with lower frequencies is affected by the direct effect of the magnetic field, although photospheric field strengths below 1500 G do not leave a significant trace on the travel-time measurements. These results could potentially be used to develop simplified travel-time inversion methods.

Measuring determinants of career satisfaction of anesthesiologists: validation of a survey instrument.

PubMed

Afonso, Anoushka M; Diaz, James H; Scher, Corey S; Beyl, Robbie A; Nair, Singh R; Kaye, Alan David

2013-06-01

To measure the parameter of job satisfaction among anesthesiologists. Survey instrument. Academic anesthesiology departments in the United States. 320 anesthesiologists who attended the annual meeting of the ASA in 2009 (95% response rate). The anonymous 50-item survey collected information on 26 independent demographic variables and 24 dependent ranked variables of career satisfaction among practicing anesthesiologists. Mean survey scores were calculated for each demographic variable and tested for statistically significant differences by analysis of variance. Questions within each domain that were internally consistent with each other within domains were identified by Cronbach's alpha ≥ 0.7. P-values ≤ 0.05 were considered statistically significant. Cronbach's alpha analysis showed strong internal consistency for 10 dependent outcome questions in the practice factor-related domain (α = 0.72), 6 dependent outcome questions in the peer factor-related domain (α = 0.71), and 8 dependent outcome questions in the personal factor-related domain (α = 0.81). Although age was not a variable, full-time status, early satisfaction within the first 5 years of practice, working with respected peers, and personal choice factors were all significantly associated with anesthesiologist job satisfaction. Improvements in factors related to job satisfaction among anesthesiologists may lead to higher early and current career satisfaction. Copyright © 2013 Elsevier Inc. All rights reserved.

Strengthening of synthetic quartz-rich sediments during time-dependent compaction due to pressure solution-precipitation compaction creep

NASA Astrophysics Data System (ADS)

Noda, H.; Okazaki, K.; Katayama, I.

2013-12-01

During diagenesis, incohesive sediments are compacted and gain strength against shear deformation for a geologically long time scale. The evolution of shear strength as well as the change in the mechanical and hydraulic characteristics under shear deformation is of significant importance in considering deformation at shallow part of the subduction zones and in accretionary prisms. Sediments after induration due to time-dependent diagenesis process probably deform with increases in porosity and permeability much more significantly than normally compacted incohesive sediments. An active fault in a shallow incohesive medium may favor thermal pressurization of pore fluid when slid rapidly, while the lack of time-dependent healing effect may cause stable (e.g., rate-strengthening) frictional property there. On the other hand, indurated sediments may deform with significant post-failure weakening, and thus exhibit localization of deformation or unstable behavior. In order to investigate how the time-dependent compaction and induration affect the mechanical and hydraulic characteristics of sediments under deformation, we have conducted a series of compaction experiments under hydrothermal conditions (at temperatures from R.T. to 500 °C, 200 MPa confining pressure, 100 MPa pore water pressure, and for various time), and following triaxial deformation experiments for the compacted samples, with monitoring permeability and storage capacity with pore pressure oscillation method [Fischer and Paterson, 1992]. Previous work [e.g., Niemeijer et at., 2003] reported that under the adopted conditions, quartz aggregate deforms by pressure solution-precipitation creep. The initial synthetic sediments have been prepared by depositing commercially available crushed quartzite the grain size of which is about 6 μm on average. 4 cm long samples have been extracted from the middle of 10 cm long deposited columns. The experiments have been performed with a gas-medium apparatus in Hiroshima University. As the compaction time and temperature increases, compressional strain increases and the synthetic sediments gain shear strength, flow stress during triaxial deformation tests. An uncooked sample yielded immediately on application of differential stress, and showed strengthening during triaxial deformation test with σ1-σ3 about 150 MPa at 0.1 compressional strain. On the other hand, a sample compacted at 500 °C for 5 hours (about 0.1 of isotropic compressional strain) deformed mainly elastically up to about 100 MPa differential stress. At 0.02 compressional strain σ1-σ3 reached 200 MPa which is the experimental limitation due to compressional strength of porous alumina spacers. In the presentation, we will focus on the relation between mechanical behavior under shear and the compressional strain during preceding compaction experiments.

Cannabis dependence in the San Francisco Family Study: age of onset of use, DSM-IV symptoms, withdrawal, and heritability

PubMed Central

Ehlers, Cindy L.; Gizer, Ian R.; Vieten, Cassandra; Gilder, David A.; Stouffer, Gina M.; Lau, Philip; Wilhelmsen, Kirk C.

2009-01-01

Cannabis is the most widely used illicit drug in the United States, yet the role of genetics in individual symptoms associated with cannabis use disorders has not been evaluated. The purpose of the present set of analyses was to describe the symptomatology and estimate the heritability of DSM-IV criteria/symptoms of cannabis dependence in a large sample of families. Participants were 2524 adults, participating in the University of California San Francisco (UCSF) Family Study of alcoholism. Seventy percent of the sample had ever used cannabis and 13.9% met DSM-IV criteria for cannabis dependence. Younger age at first cannabis use was found to be significantly associated with a shortened survival to becoming cannabis dependent. Although a greater percentage of men met criteria for cannabis dependence, women were found to demonstrate “telescoping” as indexed by a shorter survival time from initial use to dependence as compared to men. A cannabis withdrawal syndrome was identified in users, the primary symptoms of which were nervousness, appetite change, and sleep disturbance. Cannabis use (h2 = 0.31) and dependence (h2 = 0.20), age at first use, individual DSM-IV criteria for dependence, and cannabis-use associated symptoms of depression, trouble concentrating and paranoia were all found to be heritable. These findings suggest that within this population that cannabis use and dependence, as well as individual cannabis dependence symptoms have a significant heritable component, that cannabis dependence is more likely to occur when use begins during adolescence, and that the cannabis dependence syndrome includes a number of heritable untoward psychiatric side effects including withdrawal. PMID:19818563

The development of the room temperature LWIR HgCdTe detectors for free space optics communication systems

NASA Astrophysics Data System (ADS)

Martyniuk, Piotr; Gawron, Waldemar; Mikołajczyk, Janusz

2017-10-01

There are many room temperature applications to include free space optics (FSO) communication system combining quantum cascade lasers sources where HgCdTe long-wave (8-12 micrometer) infrared radiation (LWIR) detector reaching ultrafast response time < 1 ns and nearly background limited infrared photodetection (BLIP) condition are implemented. Both nearly BLIP detectivity and ultra-response time stay in contradiction in detector's optimization process. That issue could be circumvented by implementation of the hyperhemispherical GaAs immersion lens into structure to increase optical to electrical area ratio giving flexibility in terms of response time optimization. The optimization approach depends on voltage condition. The generation - recombination (GR) mechanism within active layer was found to be important for forward and weak reverse conditions while photogenerated carrier transport is significant for higher reverse bias. Except of applied voltage, the drift time strongly depends on thickness of the absorption region. Reducing the thickness of the active region, the short drift times could be reached, but that solution significantly reduces quantum efficiency and lowers detectivity. Taking that into consideration a special multilayer heterostructure designs are developed. The p-type absorber is promising due to both high ambipolar mobility and low thermal GR driven by the Auger 7 mechanism. Theoretical simulations indicate that depending on bias condition and T = 300 K the multilayer barrier LWIR HgCdTe structure could reach response time below < 100 ps while biased and <= 1 ns while unbiased. Immersed detectivity reaches > 109 cmHz1/2/W. Since commercially available FSO could operate separately in SWIR, MWIR and LWIR range - the dual band detectors should be implemented into FSO. This paper shows theoretical performance of the dual band back-to-back MWIR and LWIR HgCdTe detector operating at 300 K pointing out the MWIR active layer influence on LWIR operating regime.

Different methods to analyze stepped wedge trial designs revealed different aspects of intervention effects.

PubMed

Twisk, J W R; Hoogendijk, E O; Zwijsen, S A; de Boer, M R

2016-04-01

Within epidemiology, a stepped wedge trial design (i.e., a one-way crossover trial in which several arms start the intervention at different time points) is increasingly popular as an alternative to a classical cluster randomized controlled trial. Despite this increasing popularity, there is a huge variation in the methods used to analyze data from a stepped wedge trial design. Four linear mixed models were used to analyze data from a stepped wedge trial design on two example data sets. The four methods were chosen because they have been (frequently) used in practice. Method 1 compares all the intervention measurements with the control measurements. Method 2 treats the intervention variable as a time-independent categorical variable comparing the different arms with each other. In method 3, the intervention variable is a time-dependent categorical variable comparing groups with different number of intervention measurements, whereas in method 4, the changes in the outcome variable between subsequent measurements are analyzed. Regarding the results in the first example data set, methods 1 and 3 showed a strong positive intervention effect, which disappeared after adjusting for time. Method 2 showed an inverse intervention effect, whereas method 4 did not show a significant effect at all. In the second example data set, the results were the opposite. Both methods 2 and 4 showed significant intervention effects, whereas the other two methods did not. For method 4, the intervention effect attenuated after adjustment for time. Different methods to analyze data from a stepped wedge trial design reveal different aspects of a possible intervention effect. The choice of a method partly depends on the type of the intervention and the possible time-dependent effect of the intervention. Furthermore, it is advised to combine the results of the different methods to obtain an interpretable overall result. Copyright © 2016 Elsevier Inc. All rights reserved.

A Factorial Data Rate and Dwell Time Experiment in the National Transonic Facility

NASA Technical Reports Server (NTRS)

DeLoach, R.

2000-01-01

This report is an introductory tutorial on the application of formal experiment design methods to wind tunnel testing, for the benefit of aeronautical engineers with little formal experiment design training. It also describes the results of a Study to determine whether increases in the sample rate and dwell time of the National Transonic Facility data system Would result in significant changes in force and moment data. Increases in sample rate from 10 samples per second to 50 samples per second were examined, as were changes in dwell time from one second per data point to two seconds. These changes were examined for a representative aircraft model in a range of tunnel operating conditions defined by angles of attack from 0 deg to 3.8 degrees, total pressure from 15.0 psi to 24.1 psi, and Mach numbers from 0.52 to 0.82. No statistically significant effect was associated with the change in sample rate. The change in dwell time from one second to two seconds affected axial force measurements, and to a lesser degree normal force measurements. This dwell effect comprises a "rectification error" caused by incomplete cancellation of the positive and negative elements of certain low frequency dynamic components that are not rejected by the one-Hz low-pass filters of the data system. These low frequency effects may be due to tunnel circuit phenomena and other sources. The magnitude of the dwell effect depends on dynamic pressure, with angle of attack and Mach number influencing the strength of this dependence. An analysis is presented which suggests that the magnitude of the rectification error depends on the ratio of measurement dwell time to the period of the low-frequency dynamics, as well as the amplitude of the dynamics The essential conclusion of this analysis is that extending the dwell time (or, equivalently, replicating short-dwell data points) reduces the rectification error.

On the Influence of the Sample Absorptivity when Studying the Thermal Degradation of Materials

PubMed Central

Boulet, Pascal; Brissinger, Damien; Collin, Anthony; Acem, Zoubir; Parent, Gilles

2015-01-01

The change in absorptivity during the degradation process of materials is discussed, and its influence as one of the involved parameters in the degradation models is studied. Three materials with very different behaviors are used for the demonstration of its role: a carbon composite material, which is opaque, almost grey, a plywood slab, which is opaque and spectral-dependent and a clear PMMA slab, which is semitransparent. Data are analyzed for virgin and degraded materials at different steps of thermal degradation. It is seen that absorptivity and emissivity often reach high values in the range of 0.90–0.95 with a near-grey behavior after significant thermal aggression, but depending on the materials of interest, some significant evolution may be first observed, especially during the early stages of the degradation. Supplementary inaccuracy can come from the heterogeneity of the incident flux on the slab. As a whole, discrepancies up to 20% can be observed on the absorbed flux depending on the degradation time, mainly because of the spectral variations of the absorption and up to 10% more, depending on the position on the slab. Simple models with a constant and unique value of absorptivity may then lead to inaccuracies in the evaluation of the radiative flux absorption, with possible consequences on the pyrolysis analysis, especially for properties related to the early step of the degradation process, like the time to ignition, for example. PMID:28793512

On the Influence of the Sample Absorptivity when Studying the Thermal Degradation of Materials.

PubMed

Boulet, Pascal; Brissinger, Damien; Collin, Anthony; Acem, Zoubir; Parent, Gilles

2015-08-21

The change in absorptivity during the degradation process of materials is discussed, and its influence as one of the involved parameters in the degradation models is studied. Three materials with very different behaviors are used for the demonstration of its role: a carbon composite material, which is opaque, almost grey, a plywood slab, which is opaque and spectral-dependent and a clear PMMA slab, which is semitransparent. Data are analyzed for virgin and degraded materials at different steps of thermal degradation. It is seen that absorptivity and emissivity often reach high values in the range of 0.90-0.95 with a near-grey behavior after significant thermal aggression, but depending on the materials of interest, some significant evolution may be first observed, especially during the early stages of the degradation. Supplementary inaccuracy can come from the heterogeneity of the incident flux on the slab. As a whole, discrepancies up to 20% can be observed on the absorbed flux depending on the degradation time, mainly because of the spectral variations of the absorption and up to 10% more, depending on the position on the slab. Simple models with a constant and unique value of absorptivity may then lead to inaccuracies in the evaluation of the radiative flux absorption, with possible consequences on the pyrolysis analysis, especially for properties related to the early step of the degradation process, like the time to ignition, for example.

Operations automation using temporal dependency networks

NASA Technical Reports Server (NTRS)

Cooper, Lynne P.

1991-01-01

Precalibration activities for the Deep Space Network are time- and work force-intensive. Significant gains in availability and efficiency could be realized by intelligently incorporating automation techniques. An approach is presented to automation based on the use of Temporal Dependency Networks (TDNs). A TDN represents an activity by breaking it down into its component pieces and formalizing the precedence and other constraints associated with lower level activities. The representations are described which are used to implement a TDN and the underlying system architecture needed to support its use. The commercial applications of this technique are numerous. It has potential for application in any system which requires real-time, system-level control, and accurate monitoring of health, status, and configuration in an asynchronous environment.

Ultrafast magnon generation in an Fe film on Cu(100).

PubMed

Schmidt, A B; Pickel, M; Donath, M; Buczek, P; Ernst, A; Zhukov, V P; Echenique, P M; Sandratskii, L M; Chulkov, E V; Weinelt, M

2010-11-05

We report on a combined experimental and theoretical study of the spin-dependent relaxation processes in the electron system of an iron film on Cu(100). Spin-, time-, energy- and angle-resolved two-photon photoemission shows a strong characteristic dependence of the lifetime of photoexcited electrons on their spin and energy. Ab initio calculations as well as a many-body treatment corroborate that the observed properties are determined by relaxation processes involving magnon emission. Thereby we demonstrate that magnon emission by hot electrons occurs on the femtosecond time scale and thus provides a significant source of ultrafast spin-flip processes. Furthermore, engineering of the magnon spectrum paves the way for tuning the dynamic properties of magnetic materials.

Solutions to decrease a systematic error related to AAPH addition in the fluorescence-based ORAC assay.

PubMed

Mellado-Ortega, Elena; Zabalgogeazcoa, Iñigo; Vázquez de Aldana, Beatriz R; Arellano, Juan B

2017-02-15

Oxygen radical absorbance capacity (ORAC) assay in 96-well multi-detection plate readers is a rapid method to determine total antioxidant capacity (TAC) in biological samples. A disadvantage of this method is that the antioxidant inhibition reaction does not start in all of the 96 wells at the same time due to technical limitations when dispensing the free radical-generating azo initiator 2,2'-azobis (2-methyl-propanimidamide) dihydrochloride (AAPH). The time delay between wells yields a systematic error that causes statistically significant differences in TAC determination of antioxidant solutions depending on their plate position. We propose two alternative solutions to avoid this AAPH-dependent error in ORAC assays. Copyright © 2016 Elsevier Inc. All rights reserved.

Ultraviolet absorption spectra of shock-heated carbon dioxide and water between 900 and 3050 K

NASA Astrophysics Data System (ADS)

Schulz, C.; Koch, J. D.; Davidson, D. F.; Jeffries, J. B.; Hanson, R. K.

2002-03-01

Spectrally resolved UV absorption cross-sections between 190 and 320 nm were measured in shock-heated CO 2 between 880 and 3050 K and H 2O between 1230 and 2860 K. Absorption spectra were acquired with 10 μs time resolution using a unique kinetic spectrograph, thereby enabling comparisons with time-dependent chemical kinetic modeling of post-shock thermal decomposition and chemical reactions. Although room temperature CO 2 is transparent (σ<10 -22 cm2) at wavelengths longer than 200 nm, hot CO 2 has significant absorption (σ>10 -20 cm2) extending to wavelengths longer than 300 nm. The temperature dependence of CO 2 absorption strongly suggests sharply increased transition probabilities from excited vibrational levels.

Dose-dependent fate of GFP-E. coli in the alimentary canal of adult house flies

PubMed Central

Naveen, Kumar H.V.; Nayduch, Dana

2015-01-01

Adult house flies (Diptera: Muscidae; Musca domestica L.) can disseminate bacteria from microbe-rich substrates to areas where humans and domesticated animals reside. Because bacterial abundance fluctuates widely across substrates, flies encounter and ingest varying amounts of bacteria. We investigated the dose-dependent survival of bacteria in house flies. Flies were fed four different “doses” of GFP-expressing Escherichia coli (GFP E. coli; very low, low, medium, high, defined in text) and survival was determined at 1, 4, 10 and 22 h post-ingestion via culture and epiflourescent microscopy. Over 22 h, decline of GFP E. coli was significant for all treatments (P<0.04) except the very low dose (P=0.235). Change in survival (Δ S) did not differ between flies fed low and very low doses of bacteria across all time points, although both treatments differed from flies fed high and medium bacterial doses at several time points. At 4, 10 and 22 h, GFP E. coli Δ S significantly differed between medium and high dose-fed flies. A threshold dose, above which bacteria are detected and destroyed by house flies, may exist and likely is immune-mediated. Understanding dose-dependent bacterial survival in flies can help in predicting bacteria transmission potential. PMID:26843509

The organophosphate insecticide chlorpyrifos confers its genotoxic effects by inducing DNA damage and cell apoptosis.

PubMed

Li, Diqiu; Huang, Qingchun; Lu, Miaoqing; Zhang, Lei; Yang, Zhichuan; Zong, Mimi; Tao, Liming

2015-09-01

The organophosphate insecticide chlorpyrifos (CPF) is known to induce neurological effects, malformation and micronucleus formation, persistent developmental disorders, and maternal toxicity in rats and mice. The binding of chlorpyrifos with DNA to produce DNA adducts leads to an increasing social concern about the genotoxic risk of CPF in human, but CPF-induced cytotoxicity through DNA damage and cell apoptosis is not well understood. Here, we quantified the cytotoxicity and potential genotoxicity of CPF using the alkaline comet assay, γH2AX foci formation, and the DNA laddering assay in order to detect DNA damage and apoptosis in human HeLa and HEK293 cells in vitro. Drosophila S2 cells were used as a positive control. The alkaline comet assay showed that sublethal concentrations of CPF induced significant concentration-dependent increases in single-strand DNA breaks in the treated cells compared with the control. The percentage of γH2AX-positive HeLa cells revealed that CPF also causes DNA double-strand breaks in a time-dependent manner. Moreover, DNA fragmentation analysis demonstrated that exposure to CPF induced a significant concentration- and time-dependent increase in cell apoptosis. We conclude that CPF is a strongly genotoxic agent that induces DNA damage and cell apoptosis. Copyright © 2015 Elsevier Ltd. All rights reserved.

Smoking tobacco along with marijuana increases symptoms of cannabis dependence

PubMed Central

Ream, Geoffrey L.; Benoit, Ellen; Johnson, Bruce D.; Dunlap, Eloise

2008-01-01

Aim User practices/rituals that involve concurrent use of tobacco and marijuana – smoking blunts and “chasing” marijuana with tobacco – are hypothesized to increase cannabis dependence symptoms. Design Ethnographers administered group surveys to a diverse, purposive sample of marijuana users who appeared to be 17–35 years old. Setting New York City, including non-impoverished areas of Manhattan, the transitional area of East Village/Lower East Side, low-income areas of northern Manhattan and South Bronx, and diverse areas of Brooklyn and Queens. Participants 481 marijuana users ages 14–35, 57% male, 43% female; 27% White, 30% Black, 19% Latino, 5% Asian, 20% of other/multiple race. Measurements Among many other topics, group surveys measured cannabis dependence symptoms; frequencies of chasing, blunt smoking, joint/pipe smoking, using marijuana while alone, and general tobacco use; and demographic factors. Findings Blunt smoking and chasing marijuana with tobacco were each uniquely associated with five of the seven cannabis dependence symptoms. Across symptoms, predicted odds were 2.4–4.1 times greater for participants who smoked blunts on all 30 of the past 30 days than for participants who did not smoke blunts in the past 30 days. Significant increases in odds over the whole range of the five-point chasing frequency measure (from never to always) ranged from 3.4 times to 5.1 times. Conclusions Using tobacco with marijuana – smoking blunts and “chasing” marijuana with tobacco – contributes to cannabis dependence symptoms. Treatment for cannabis dependence may be more effective it addresses the issue of concurrent tobacco use. PMID:18339491

The impact of multiple memory formation on dendritic complexity in the hippocampus and anterior cingulate cortex assessed at recent and remote time points

PubMed Central

Wartman, Brianne C.; Holahan, Matthew R.

2014-01-01

Consolidation processes, involving synaptic and systems level changes, are suggested to stabilize memories once they are formed. At the synaptic level, dendritic structural changes are associated with long-term memory storage. At the systems level, memory storage dynamics between the hippocampus and anterior cingulate cortex (ACC) may be influenced by the number of sequentially encoded memories. The present experiment utilized Golgi-Cox staining and neuron reconstruction to examine recent and remote structural changes in the hippocampus and ACC following training on three different behavioral procedures. Rats were trained on one hippocampal-dependent task only (a water maze task), two hippocampal-dependent tasks (a water maze task followed by a radial arm maze task), or one hippocampal-dependent and one non-hippocampal-dependent task (a water maze task followed by an operant conditioning task). Rats were euthanized recently or remotely. Brains underwent Golgi-Cox processing and neurons were reconstructed using Neurolucida software (MicroBrightField, Williston, VT, USA). Rats trained on two hippocampal-dependent tasks displayed increased dendritic complexity compared to control rats, in neurons examined in both the ACC and hippocampus at recent and remote time points. Importantly, this behavioral group showed consistent, significant structural differences in the ACC compared to the control group at the recent time point. These findings suggest that taxing the demand placed upon the hippocampus, by training rats on two hippocampal-dependent tasks, engages synaptic and systems consolidation processes in the ACC at an accelerated rate for recent and remote storage of spatial memories. PMID:24795581

Characterization of covalent binding of N'-nitrosonornicotine in rat liver microsomes

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

Hughes, M.F.; Brock, W.J.; Marion, L.J.

1986-01-01

The metabolism of the carcinogenic nitrosamine, N'-nitrosonornicotine (NNN), to reactive intermediates which bind covalently was assessed using male Sprague-Dawley rat liver microsomes. The NADPH-dependent covalent binding of (/sup 14/C)NNN was linear with time up to 90 min and protein concentration up to 3.0 mg/ml. The apparent Km and Vmax of the binding were determined from the initial velocities and found to be 0.91 mM and 4.7 pmol/min/mg protein, respectively. Although NNN is not a hepatocarcinogen, this amount of NADPH-dependent covalent binding is 7-fold greater than that reported for dimethylnitrosamine, a potent hepatocarcinogen. Extensive covalent binding of (/sup 14/C)NNN to livermore » and muscle microsomal protein was also present in the absence of an NADPH-generating system and in the presence of 50% methanol, indicating a non-enzymatically mediated reaction. Addition of the nucleophiles glutathione, cysteine and N-acetylcysteine significantly decreased (p less than 0.01) the non-NADPH-dependent binding, but did not affect NADPH-dependent binding. In vitro addition of the cytochrome P-450 inhibitors metyrapone, piperonyl butoxide and SKF-525A significantly decreased (p less than 0.05) NADPH-dependent binding of (14C)NNN by 27-40%. NADH did not replace NADPH in supporting covalent binding. Replacement of an air atmosphere with nitrogen or CO:O2 (8:2) significantly decreased (p less than 0.05) NADPH-dependent binding of (/sup 14/C)NNN by 40 and 27%, respectively. Aroclor 1254 pre-treatment of the rats did not enhance the NADPH-dependent binding of (/sup 14/C)NNN. These data indicate that cytochrome P-450 is at least in part responsible for the metabolic activation of the carcinogen NNN but also suggest additional mechanisms of activation.« less

Individual Differences in Motor Timing and Its Relation to Cognitive and Fine Motor Skills

PubMed Central

Lorås, Håvard; Stensdotter, Ann-Katrin; Öhberg, Fredrik; Sigmundsson, Hermundur

2013-01-01

The present study investigated the relationship between individual differences in timing movements at the level of milliseconds and performance on selected cognitive and fine motor skills. For this purpose, young adult participants (N = 100) performed a repetitive movement task paced by an auditory metronome at different rates. Psychometric measures included the digit-span and symbol search subtasks from the Wechsler battery as well as the Raven SPM. Fine motor skills were assessed with the Purdue Pegboard test. Motor timing performance was significantly related (mean r = .3) to cognitive measures, and explained both unique and shared variance with information-processing speed of Raven's scores. No significant relations were found between motor timing measures and fine motor skills. These results show that individual differences in cognitive and motor timing performance is to some extent dependent upon shared processing not associated with individual differences in manual dexterity. PMID:23874952

Individual differences in motor timing and its relation to cognitive and fine motor skills.

PubMed

Lorås, Håvard; Stensdotter, Ann-Katrin; Öhberg, Fredrik; Sigmundsson, Hermundur

2013-01-01

The present study investigated the relationship between individual differences in timing movements at the level of milliseconds and performance on selected cognitive and fine motor skills. For this purpose, young adult participants (N = 100) performed a repetitive movement task paced by an auditory metronome at different rates. Psychometric measures included the digit-span and symbol search subtasks from the Wechsler battery as well as the Raven SPM. Fine motor skills were assessed with the Purdue Pegboard test. Motor timing performance was significantly related (mean r = .3) to cognitive measures, and explained both unique and shared variance with information-processing speed of Raven's scores. No significant relations were found between motor timing measures and fine motor skills. These results show that individual differences in cognitive and motor timing performance is to some extent dependent upon shared processing not associated with individual differences in manual dexterity.

Cytosolic increased labile Zn2+ contributes to arrhythmogenic action potentials in left ventricular cardiomyocytes through protein thiol oxidation and cellular ATP depletion.

PubMed

Degirmenci, Sinan; Olgar, Yusuf; Durak, Aysegul; Tuncay, Erkan; Turan, Belma

2018-07-01

Intracellular labile (free) Zn 2+ -level ([Zn 2+ ] i ) is low and increases markedly under pathophysiological conditions in cardiomyocytes. High [Zn 2+ ] i is associated with alterations in excitability and ionic-conductances while exact mechanisms are not clarified yet. Therefore, we examined the elevated-[Zn 2+ ] i on some sarcolemmal ionic-mechanisms, which can mediate cardiomyocyte dysfunction. High-[Zn 2+ ] i induced significant changes in action potential (AP) parameters, including depolarization in resting membrane-potential and prolongations in AP-repolarizing phases. We detected also the time-dependent effects such as induction of spontaneous APs at the time of ≥ 3 min following [Zn 2+ ] i increases, a manner of cellular ATP dependent and reversible with disulfide-reducing agent dithiothreitol, DTT. High-[Zn 2+ ] i induced inhibitions in voltage-dependent K + -channel currents, such as transient outward K + -currents, I to , steady-state currents, I ss and inward-rectifier K + -currents, I K1 , reversible with DTT seemed to be responsible from the prolongations in APs. We, for the first time, demonstrated that lowering cellular ATP level induced significant decreaeses in both I ss and I K1 , while no effect on I to . However, the increased-[Zn 2+ ] i could induce marked activation in ATP-sensitive K + -channel currents, I KATP , depending on low cellular ATP and thiol-oxidation levels of these channels. The mRNA levels of Kv4.3, Kv1.4 and Kv2.1 were depressed markedly with increased-[Zn 2+ ] i with no change in mRNA level of Kv4.2, while the mRNA level of I KATP subunit, SUR2A was increased significantly with increased-[Zn 2+ ] i , being reversible with DTT. Overall we demonstrated that high-[Zn 2+ ] i, even if nanomolar levels, alters cardiac function via prolonged APs of cardiomyocytes, at most, due to inhibitions in voltage-dependent K + -currents, although activation of I KATP is playing cardioprotective role, through some biochemical changes in cellular ATP- and thiol-oxidation levels. It seems, a well-controlled [Zn 2+ ] i can be novel therapeutic target for cardiac complications under pathological conditions including oxidative stress. Copyright © 2018 Elsevier GmbH. All rights reserved.

Progression of spinal deformity in wheelchair-dependent patients with Duchenne muscular dystrophy who are not treated with steroids: coronal plane (scoliosis) and sagittal plane (kyphosis, lordosis) deformity.

PubMed

Shapiro, F; Zurakowski, D; Bui, T; Darras, B T

2014-01-01

We determined the frequency, rate and extent of development of scoliosis (coronal plane deformity) in wheelchair-dependent patients with Duchenne muscular dystrophy (DMD) who were not receiving steroid treatment. We also assessed kyphosis and lordosis (sagittal plane deformity). The extent of scoliosis was assessed on sitting anteroposterior (AP) spinal radiographs in 88 consecutive non-ambulatory patients with DMD. Radiographs were studied from the time the patients became wheelchair-dependent until the time of spinal fusion, or the latest assessment if surgery was not undertaken. Progression was estimated using a longitudinal mixed-model regression analysis to handle repeated measurements. Scoliosis ≥ 10° occurred in 85 of 88 patients (97%), ≥ 20° in 78 of 88 (89%) and ≥ 30° in 66 of 88 patients (75%). The fitted longitudinal model revealed that time in a wheelchair was a highly significant predictor of the magnitude of the curve, independent of the age of the patient (p < 0.001). Scoliosis developed in virtually all DMD patients not receiving steroids once they became wheelchair-dependent, and the degree of deformity deteriorated over time. In general, scoliosis increased at a constant rate, beginning at the time of wheelchair-dependency (p < 0.001). In some there was no scoliosis for as long as three years after dependency, but scoliosis then developed and increased at a constant rate. Some patients showed a rapid increase in the rate of progression of the curve after a few years - the clinical phenomenon of a rapidly collapsing curve over a few months. A sagittal plane kyphotic deformity was seen in 37 of 60 patients (62%) with appropriate radiographs, with 23 (38%) showing lumbar lordosis (16 (27%) abnormal and seven (11%) normal). This study provides a baseline to assess the effects of steroids and other forms of treatment on the natural history of scoliosis in patients with DMD, and an approach to assessing spinal deformity in the coronal and sagittal planes in wheelchair-dependent patients with other neuromuscular disorders.

Seismic hazard assessment over time: Modelling earthquakes in Taiwan

NASA Astrophysics Data System (ADS)

Chan, Chung-Han; Wang, Yu; Wang, Yu-Ju; Lee, Ya-Ting

2017-04-01

To assess the seismic hazard with temporal change in Taiwan, we develop a new approach, combining both the Brownian Passage Time (BPT) model and the Coulomb stress change, and implement the seismogenic source parameters by the Taiwan Earthquake Model (TEM). The BPT model was adopted to describe the rupture recurrence intervals of the specific fault sources, together with the time elapsed since the last fault-rupture to derive their long-term rupture probability. We also evaluate the short-term seismicity rate change based on the static Coulomb stress interaction between seismogenic sources. By considering above time-dependent factors, our new combined model suggests an increased long-term seismic hazard in the vicinity of active faults along the western Coastal Plain and the Longitudinal Valley, where active faults have short recurrence intervals and long elapsed time since their last ruptures, and/or short-term elevated hazard levels right after the occurrence of large earthquakes due to the stress triggering effect. The stress enhanced by the February 6th, 2016, Meinong ML 6.6 earthquake also significantly increased rupture probabilities of several neighbouring seismogenic sources in Southwestern Taiwan and raised hazard level in the near future. Our approach draws on the advantage of incorporating long- and short-term models, to provide time-dependent earthquake probability constraints. Our time-dependent model considers more detailed information than any other published models. It thus offers decision-makers and public officials an adequate basis for rapid evaluations of and response to future emergency scenarios such as victim relocation and sheltering.

Identification of Time-Varying Pilot Control Behavior in Multi-Axis Control Tasks

NASA Technical Reports Server (NTRS)

Zaal, Peter M. T.; Sweet, Barbara T.

2012-01-01

Recent developments in fly-by-wire control architectures for rotorcraft have introduced new interest in the identification of time-varying pilot control behavior in multi-axis control tasks. In this paper a maximum likelihood estimation method is used to estimate the parameters of a pilot model with time-dependent sigmoid functions to characterize time-varying human control behavior. An experiment was performed by 9 general aviation pilots who had to perform a simultaneous roll and pitch control task with time-varying aircraft dynamics. In 8 different conditions, the axis containing the time-varying dynamics and the growth factor of the dynamics were varied, allowing for an analysis of the performance of the estimation method when estimating time-dependent parameter functions. In addition, a detailed analysis of pilots adaptation to the time-varying aircraft dynamics in both the roll and pitch axes could be performed. Pilot control behavior in both axes was significantly affected by the time-varying aircraft dynamics in roll and pitch, and by the growth factor. The main effect was found in the axis that contained the time-varying dynamics. However, pilot control behavior also changed over time in the axis not containing the time-varying aircraft dynamics. This indicates that some cross coupling exists in the perception and control processes between the roll and pitch axes.

Time-Dependent Effects of Localized Inflammation on Peripheral Clock Gene Expression in Rats

PubMed Central

Westfall, Susan; Aguilar-Valles, Argel; Mongrain, Valérie; Luheshi, Giamal N.; Cermakian, Nicolas

2013-01-01

Many aspects of the immune system, including circulating cytokine levels as well as counts and function of various immune cell types, present circadian rhythms. Notably, the mortality rate of animals subjected to high doses of lipopolysaccharide is dependent on the time of treatment. In addition, the severity of symptoms of various inflammatory conditions follows a daily rhythmic pattern. The mechanisms behind the crosstalk between the circadian and immune systems remain elusive. Here we demonstrate that localized inflammation induced by turpentine oil (TURP) causes a time-dependent induction of interleukin (IL)-6 and has time-, gene- and tissue-specific effects on clock gene expression. More precisely, TURP blunts the peak of Per1 and Per2 expression in the liver while in other tissues, the expression nadir is elevated. In contrast, Rev-erbα expression remains relatively unaffected by TURP treatment. Co-treatment with the anti-inflammatory agent IL-1 receptor antagonist (IL-1Ra) did not alter the response of Per2 to TURP treatment in liver, despite the reduced induction of fever and IL-6 serum levels. This indicates that the TURP-mediated changes of Per2 in the liver might be due to factors other than systemic IL-6 and fever. Accordingly, IL-6 treatment had no effect on clock gene expression in HepG2 liver carcinoma cells. Altogether, we show that localized inflammation causes significant time-dependent changes in peripheral circadian clock gene expression, via a mechanism likely involving mediators independent from IL-6 and fever. PMID:23527270

Hybrid Pareto artificial bee colony algorithm for multi-objective single machine group scheduling problem with sequence-dependent setup times and learning effects.

PubMed

Yue, Lei; Guan, Zailin; Saif, Ullah; Zhang, Fei; Wang, Hao

2016-01-01

Group scheduling is significant for efficient and cost effective production system. However, there exist setup times between the groups, which require to decrease it by sequencing groups in an efficient way. Current research is focused on a sequence dependent group scheduling problem with an aim to minimize the makespan in addition to minimize the total weighted tardiness simultaneously. In most of the production scheduling problems, the processing time of jobs is assumed as fixed. However, the actual processing time of jobs may be reduced due to "learning effect". The integration of sequence dependent group scheduling problem with learning effects has been rarely considered in literature. Therefore, current research considers a single machine group scheduling problem with sequence dependent setup times and learning effects simultaneously. A novel hybrid Pareto artificial bee colony algorithm (HPABC) with some steps of genetic algorithm is proposed for current problem to get Pareto solutions. Furthermore, five different sizes of test problems (small, small medium, medium, large medium, large) are tested using proposed HPABC. Taguchi method is used to tune the effective parameters of the proposed HPABC for each problem category. The performance of HPABC is compared with three famous multi objective optimization algorithms, improved strength Pareto evolutionary algorithm (SPEA2), non-dominated sorting genetic algorithm II (NSGAII) and particle swarm optimization algorithm (PSO). Results indicate that HPABC outperforms SPEA2, NSGAII and PSO and gives better Pareto optimal solutions in terms of diversity and quality for almost all the instances of the different sizes of problems.

SALSA3D: A Tomographic Model of Compressional Wave Slowness in the Earth’s Mantle for Improved Travel-Time Prediction and Travel-Time Prediction Uncertainty

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

Ballard, Sanford; Hipp, James R.; Begnaud, Michael L.

The task of monitoring the Earth for nuclear explosions relies heavily on seismic data to detect, locate, and characterize suspected nuclear tests. In this study, motivated by the need to locate suspected explosions as accurately and precisely as possible, we developed a tomographic model of the compressional wave slowness in the Earth’s mantle with primary focus on the accuracy and precision of travel-time predictions for P and Pn ray paths through the model. Path-dependent travel-time prediction uncertainties are obtained by computing the full 3D model covariance matrix and then integrating slowness variance and covariance along ray paths from source tomore » receiver. Path-dependent travel-time prediction uncertainties reflect the amount of seismic data that was used in tomography with very low values for paths represented by abundant data in the tomographic data set and very high values for paths through portions of the model that were poorly sampled by the tomography data set. The pattern of travel-time prediction uncertainty is a direct result of the off-diagonal terms of the model covariance matrix and underscores the importance of incorporating the full model covariance matrix in the determination of travel-time prediction uncertainty. In addition, the computed pattern of uncertainty differs significantly from that of 1D distance-dependent travel-time uncertainties computed using traditional methods, which are only appropriate for use with travel times computed through 1D velocity models.« less

SALSA3D: A Tomographic Model of Compressional Wave Slowness in the Earth’s Mantle for Improved Travel-Time Prediction and Travel-Time Prediction Uncertainty

DOE PAGES

Ballard, Sanford; Hipp, James R.; Begnaud, Michael L.; ...

2016-10-11

The task of monitoring the Earth for nuclear explosions relies heavily on seismic data to detect, locate, and characterize suspected nuclear tests. In this study, motivated by the need to locate suspected explosions as accurately and precisely as possible, we developed a tomographic model of the compressional wave slowness in the Earth’s mantle with primary focus on the accuracy and precision of travel-time predictions for P and Pn ray paths through the model. Path-dependent travel-time prediction uncertainties are obtained by computing the full 3D model covariance matrix and then integrating slowness variance and covariance along ray paths from source tomore » receiver. Path-dependent travel-time prediction uncertainties reflect the amount of seismic data that was used in tomography with very low values for paths represented by abundant data in the tomographic data set and very high values for paths through portions of the model that were poorly sampled by the tomography data set. The pattern of travel-time prediction uncertainty is a direct result of the off-diagonal terms of the model covariance matrix and underscores the importance of incorporating the full model covariance matrix in the determination of travel-time prediction uncertainty. In addition, the computed pattern of uncertainty differs significantly from that of 1D distance-dependent travel-time uncertainties computed using traditional methods, which are only appropriate for use with travel times computed through 1D velocity models.« less

Ghrelin system in alcohol-dependent subjects: role of plasma ghrelin levels in alcohol drinking and craving

PubMed Central

Leggio, Lorenzo; Ferrulli, Anna; Cardone, Silvia; Nesci, Antonio; Miceli, Antonio; Malandrino, Noemi; Capristo, Esmeralda; Canestrelli, Benedetta; Monteleone, Palmiero; Kenna, George A.; Swift, Robert M.; Addolorato, Giovanni

2016-01-01

Animal studies suggest that the gut-brain peptide ghrelin plays an important role in the neurobiology of alcohol dependence (AD). Human studies show an effect of alcohol on ghrelin levels and a correlation between ghrelin levels and alcohol craving in alcoholics. This investigation consisted of two studies. Study 1 was a 12-week study with alcohol-dependent subjects, where plasma ghrelin determinations were assessed four times (T0-T3) and related to alcohol intake and craving [Penn Alcohol Craving Score (PACS) and Obsessive Compulsive Drinking Scale (OCDS)]. Serum growth hormone (GH) levels and assessment of the nutritional/metabolic status were also performed. Study 2 was a pilot case-control study to assess ghrelin gene polymorphisms (Arg51Gln and Leu72Met) in alcohol-dependent individuals. Study 1 showed no significant differences in ghrelin levels in the whole sample, while there was a statistical difference for ghrelin between non-abstinent and abstinent subjects. Baseline ghrelin levels were significantly and positively correlated with the PACS score at T1 and with all craving scores both at T2 and T3 (PACS, OCDS, obsessive and compulsive OCDS subscores). In Study 2, although there was a higher frequency of the Leu72Met ghrelin gene polymorphism in alcohol-dependent individuals, the distribution between healthy controls and alcohol dependent individuals was not statistically significant. This investigation suggests that ghrelin is potentially able to affect alcohol-seeking behaviors, such as alcohol drinking and craving, representing a new potential neuropharmacological target for AD. PMID:21392177

Dronabinol for the Treatment of Cannabis Dependence: A Randomized, Double-Blind, Placebo-Controlled Trial

PubMed Central

Levin, Frances R.; Mariani, John J.; Brooks, Daniel J.; Pavlicova, Martina; Cheng, Wendy; Nunes, Edward

2011-01-01

Cannabis dependence is a substantial public health problem. Behavioral treatments have shown promise, but there are no effective medications for cannabis dependence. The purpose of this study was to evaluate the safety and efficacy of dronabinol, a synthetic form of delta-9-tetrahydrocannabinol, a naturally occurring pharmacologically active component of marijuana, in treating cannabis dependence. 156 cannabis-dependent adults were enrolled in a randomized, double-blind, placebo-controlled, 12-week trial. After a 1-week placebo lead-in phase, participants were randomized to receive dronabinol 20 mg twice a day or placebo. Doses were maintained until the end of week 8 and then tapered off over 2 weeks. All participants received weekly motivational enhancement and relapse prevention therapy. Marijuana use was assessed using the timeline followback method. There was no significant difference between treatment groups in the proportion of participants who achieved 2 weeks of abstinence at the end of the maintenance phase (dronabinol: 17.7%; placebo: 15.6%). Although both groups showed a reduction in marijuana use over time, there were no differences between the groups. Treatment retention was significantly higher at the end of the maintenance phase on dronabinol (77%), compared to placebo (61%) (P = .02), and withdrawal symptoms were significantly lower on dronabinol than placebo (P= .02). This is the first trial using an agonist substitution strategy for treatment of cannabis dependence. Dronabinol showed promise, it was well-tolerated, and improved treatment retention and withdrawal symptoms. Future trials might test higher doses, combinations of dronabinol with other medications with complementary mechanisms, or with more potent behavioral interventions. PMID:21310551

Ghrelin system in alcohol-dependent subjects: role of plasma ghrelin levels in alcohol drinking and craving.

PubMed

Leggio, Lorenzo; Ferrulli, Anna; Cardone, Silvia; Nesci, Antonio; Miceli, Antonio; Malandrino, Noemi; Capristo, Esmeralda; Canestrelli, Benedetta; Monteleone, Palmiero; Kenna, George A; Swift, Robert M; Addolorato, Giovanni

2012-03-01

Animal studies suggest that the gut-brain peptide ghrelin plays an important role in the neurobiology of alcohol dependence (AD). Human studies show an effect of alcohol on ghrelin levels and a correlation between ghrelin levels and alcohol craving in alcoholics. This investigation consisted of two studies. Study 1 was a 12-week study with alcohol-dependent subjects, where plasma ghrelin determinations were assessed four times (T0-T3) and related to alcohol intake and craving [Penn Alcohol Craving Score (PACS) and Obsessive Compulsive Drinking Scale (OCDS)]. Serum growth hormone levels and assessment of the nutritional/metabolic status were also performed. Study 2 was a pilot case-control study to assess ghrelin gene polymorphisms (Arg51Gln and Leu72Met) in alcohol-dependent individuals. Study 1 showed no significant differences in ghrelin levels in the whole sample, while there was a statistical difference for ghrelin between non-abstinent and abstinent subjects. Baseline ghrelin levels were significantly and positively correlated with the PACS score at T1 and with all craving scores both at T2 and T3 (PACS, OCDS, obsessive and compulsive OCDS subscores). In Study 2, although there was a higher frequency of the Leu72Met ghrelin gene polymorphism in alcohol-dependent individuals, the distribution between healthy controls and alcohol dependent individuals was not statistically significant. This investigation suggests that ghrelin is potentially able to affect alcohol-seeking behaviors, such as alcohol drinking and craving, representing a new potential neuropharmacological target for AD. © 2011 The Authors, Addiction Biology © 2011 Society for the Study of Addiction.

Updating prognosis of cirrhosis by Cox's regression model using Child-Pugh score and aminopyrine breath test as time-dependent covariates.

PubMed

Merkel, C; Morabito, A; Sacerdoti, D; Bolognesi, M; Angeli, P; Gatta, A

1998-06-01

The determination of aminopyrine breath test on entry into the study was recently shown to improve the accuracy of prediction of death based on the Child-Pugh classification, but the possible usefulness of serial determinations of both parameters has not been assessed. In the present study, we aimed at evaluating whether serial determinations of aminopyrine breath test and Child-Pugh score improve prognostic accuracy in patients with cirrhosis, compared with determinations obtained only on admission. In 74 patients with liver cirrhosis aminopyrine breath test and Child-Pugh score were obtained upon entry into the study. Patients were followed with sequential aminopyrine breath tests and assessments of the Child-Pugh score every 4-6 months. A total number of 232 determinations were obtained. During follow-up 45 patients died, on average after 12 months of follow-up. Child-Pugh score improved in the beginning of follow-up, and then remained fairly constant; aminopyrine breath test showed no improvement in the beginning of follow-up, but rather a slowly progressive decline. In patients who died, both the Child-Pugh score and the metabolism of aminopyrine were significantly more impaired in the last year preceding death (p < 0.05). Applying Cox's regression model with time-dependent covariates, Child-Pugh score and aminopyrine breath test were independent significant predictors of survival. The model with time-dependent covariates explained the observed survival much better than the model with time-fixed covariates (chi-sq. explained by regression = 31.45 vs 11.97; d.f. = 2; p = 0.0000001 vs 0.003). These data suggest that serial determinations of Child-Pugh score and aminopyrine breath test can be used to efficiently update prognosis of cirrhosis.

PM2.5-induced alterations of cell cycle associated gene expression in lung cancer cells and rat lung tissues.

PubMed

Zhao, Hui; Yang, Biao; Xu, Jia; Chen, Dong-Mei; Xiao, Chun-Ling

2017-06-01

The aim of the current study was to investigate the expression of cell cycle-associated genes induced by fine particulate matter (PM 2.5 ) in lung cancer cell line and tissues. The pulmonary lymph node metastasis cells (H292) were treated with PM 2.5 in vitro. Wistar rats were used to perform an in vivo study. Rats were randomly assigned to experiment and control groups and those in the experiment group were exposed to PM 2.5 once every 15 d, while those in the control group were exposed to normal saline. The cell cycle-associated genes expression was analyzed by real-time PCR. Trachea and lung tissues of rats were processed for scanning electron microscopic (SEM) examinations. Exposure of H292 cells to PM 2.5 dramatically increased the expressions of p53 and cyclin-dependent kinase 2 (CDK2) after 24h of exposure (p<0.01) and markedly increased the expressions of the cell division cycle 2 (Cdc2) and cyclin B after 48h of exposure (p<0.01), while those genes expressions were significantly reduced after 72h of exposure, at which time the expression of p21 was predominant (p<0.01). In vivo studies further demonstrated these results. The results of SEM suggested that both of the trachea and lung tissues were damaged and the degree of damage was time-dependent. In conclusion, PM 2.5 can induce significantly alterations of p53 and CDK2 in the early phase, Cdc2 and cyclin B in mid-term and p21 in long-term exposure. The degree of PM 2.5 -induced damage to the trachea and lung tissue was time-dependent. Copyright © 2017. Published by Elsevier B.V.

Time-dependent differences in cortical measures and their associations with behavioral measures following mild traumatic brain injury.

PubMed

Bajaj, Sahil; Dailey, Natalie S; Rosso, Isabelle M; Rauch, Scott L; Killgore, William D S

2018-05-01

There is currently a critical need to establish an improved understanding of time-dependent differences in brain structure following mild traumatic brain injury (mTBI). We compared differences in brain structure, specifically cortical thickness (CT), cortical volume (CV), and cortical surface area (CSA) in 54 individuals who sustained a recent mTBI and 33 healthy controls (HCs). Individuals with mTBI were split into three groups, depending on their time since injury. By comparing structural measures between mTBI and HC groups, differences in CT reflected cortical thickening within several areas following 0-3 (time-point, TP1) and 3-6 months (TP2) post-mTBI. Compared with the HC group, the mTBI group at TP2 showed lower CSA within several areas. Compared with the mTBI group at TP2, the mTBI group during the most chronic stage (TP3: 6-18 months post-mTBI) showed significantly higher CSA in several areas. All the above reported differences in CT and CSA were significant at a cluster-forming p < .01 (corrected for multiple comparisons). We also found that in the mTBI group at TP2, CT within two clusters (i.e., the left rostral middle frontal gyrus (L. RMFG) and the right postcentral gyrus (R. PostCG)) was negatively correlated with basic attention abilities (L. RMFG: r = -.41, p = .05 and R. PostCG: r = -.44, p = .03). Our findings suggest that alterations in CT and associated neuropsychological assessments may be more prominent during the early stages of mTBI. However, alterations in CSA may reflect compensatory structural recovery during the chronic stages of mTBI. © 2018 Wiley Periodicals, Inc.

Early sex-specific modulation of the molecular clock in trauma.

PubMed

Mehraj, Vikram; Wiramus, Sandrine; Capo, Christian; Leone, Marc; Mege, Jean-Louis; Textoris, Julien

2014-01-01

Immune system biology and most physiologic functions are tightly linked to circadian rhythms. Time of day-dependent variations in many biologic parameters also play a fundamental role in the disease process. We previously showed that the genes encoding the peripheral molecular clock were modulated in a sex-dependent manner in Q fever. Here, we examined severe trauma patients at admission to the intensive care unit. Using quantitative real-time polymerase chain reaction, the whole-blood expression of the molecular clock components ARNTL, CLOCK, and PER2 was assessed in male and female trauma patients. Healthy volunteers of both sexes were used as controls. We observed a significant overexpression of both ARNTL and CLOCK in male trauma patients. We report, for the first time, the sex-related modulation of the molecular clock genes in the blood following severe trauma. These results emphasize the role of circadian rhythms in the immune response in trauma patients. Epidemiologic study, level IV.

Green's Functions from Real-Time Bold-Line Monte Carlo Calculations: Spectral Properties of the Nonequilibrium Anderson Impurity Model

NASA Astrophysics Data System (ADS)

Cohen, Guy; Gull, Emanuel; Reichman, David R.; Millis, Andrew J.

2014-04-01

The nonequilibrium spectral properties of the Anderson impurity model with a chemical potential bias are investigated within a numerically exact real-time quantum Monte Carlo formalism. The two-time correlation function is computed in a form suitable for nonequilibrium dynamical mean field calculations. Additionally, the evolution of the model's spectral properties are simulated in an alternative representation, defined by a hypothetical but experimentally realizable weakly coupled auxiliary lead. The voltage splitting of the Kondo peak is confirmed and the dynamics of its formation after a coupling or gate quench are studied. This representation is shown to contain additional information about the dot's population dynamics. Further, we show that the voltage-dependent differential conductance gives a reasonable qualitative estimate of the equilibrium spectral function, but significant qualitative differences are found including incorrect trends and spurious temperature dependent effects.

Relativistic Coulomb Excitation within the Time Dependent Superfluid Local Density Approximation

NASA Astrophysics Data System (ADS)

Stetcu, I.; Bertulani, C. A.; Bulgac, A.; Magierski, P.; Roche, K. J.

2015-01-01

Within the framework of the unrestricted time-dependent density functional theory, we present for the first time an analysis of the relativistic Coulomb excitation of the heavy deformed open shell nucleus 238U. The approach is based on the superfluid local density approximation formulated on a spatial lattice that can take into account coupling to the continuum, enabling self-consistent studies of superfluid dynamics of any nuclear shape. We compute the energy deposited in the target nucleus as a function of the impact parameter, finding it to be significantly larger than the estimate using the Goldhaber-Teller model. The isovector giant dipole resonance, the dipole pygmy resonance, and giant quadrupole modes are excited during the process. The one-body dissipation of collective dipole modes is shown to lead a damping width Γ↓≈0.4 MeV and the number of preequilibrium neutrons emitted has been quantified.

Dynamics of exciton magnetic polarons in CdMnSe/CdMgSe quantum wells: Effect of self-localization

NASA Astrophysics Data System (ADS)

Akimov, I. A.; Godde, T.; Kavokin, K. V.; Yakovlev, D. R.; Reshina, I. I.; Sedova, I. V.; Sorokin, S. V.; Ivanov, S. V.; Kusrayev, Yu. G.; Bayer, M.

2017-04-01

We study the exciton magnetic polaron (EMP) formation in (Cd,Mn)Se/(Cd,Mg)Se diluted-magnetic-semiconductor quantum wells by using time-resolved photoluminescence (PL). The magnetic-field and temperature dependencies of this dynamics allow us to separate the nonmagnetic and magnetic contributions to the exciton localization. We deduce the EMP energy of 14 meV, which is in agreement with time-integrated measurements based on selective excitation and the magnetic-field dependence of the PL circular polarization degree. The polaron formation time of 500 ps is significantly longer than the corresponding values reported earlier. We propose that this behavior is related to strong self-localization of the EMP, accompanied with a squeezing of the heavy-hole envelope wave function. This conclusion is also supported by the decrease of the exciton lifetime from 600 ps to 200-400 ps with increasing magnetic field and temperature.

Relativistic Coulomb excitation within the time dependent superfluid local density approximation

DOE PAGES

Stetcu, I.; Bertulani, C. A.; Bulgac, A.; ...

2015-01-06

Within the framework of the unrestricted time-dependent density functional theory, we present for the first time an analysis of the relativistic Coulomb excitation of the heavy deformed open shell nucleus 238U. The approach is based on the superfluid local density approximation formulated on a spatial lattice that can take into account coupling to the continuum, enabling self-consistent studies of superfluid dynamics of any nuclear shape. We compute the energy deposited in the target nucleus as a function of the impact parameter, finding it to be significantly larger than the estimate using the Goldhaber-Teller model. The isovector giant dipole resonance, themore » dipole pygmy resonance, and giant quadrupole modes are excited during the process. As a result, the one-body dissipation of collective dipole modes is shown to lead a damping width Γ↓≈0.4 MeV and the number of preequilibrium neutrons emitted has been quantified.« less

Framework flexibility of ZIF-8 under liquid intrusion: discovering time-dependent mechanical response and structural relaxation.

PubMed

Sun, Yueting; Li, Yibing; Tan, Jin-Chong

2018-04-18

The structural flexibility of a topical zeolitic imidazolate framework with sodalite topology, termed ZIF-8, has been elucidated through liquid intrusion under moderate pressures (i.e. tens of MPa). By tracking the evolution of water intrusion pressure under cyclic conditions, we interrogate the role of the gate-opening mechanism controlling the size variation of the pore channels of ZIF-8. Interestingly, we demonstrate that its channel deformation is recoverable through structural relaxation over time, hence revealing the viscoelastic mechanical response in ZIF-8. We propose a simple approach employing a glycerol-water solution mixture, which can significantly enhance the sensitivity of intrusion pressure for the detection of structural deformation in ZIF-8. By leveraging the time-dependent gate-opening phenomenon in ZIF-8, we achieved a notable improvement (50%) in energy dissipation during multicycle mechanical deformation experiments.

Modulation of CD4(+) T cell-dependent specific cytotoxic CD8(+) T cells differentiation and proliferation by the timing of increase in the pathogen load.

PubMed

Tzelepis, Fanny; Persechini, Pedro M; Rodrigues, Mauricio M

2007-04-25

Following infection with viruses, bacteria or protozoan parasites, naïve antigen-specific CD8(+) T cells undergo a process of differentiation and proliferation to generate effector cells. Recent evidences suggest that the timing of generation of specific effector CD8(+) T cells varies widely according to different pathogens. We hypothesized that the timing of increase in the pathogen load could be a critical parameter governing this process. Using increasing doses of the protozoan parasite Trypanosoma cruzi to infect C57BL/6 mice, we observed a significant acceleration in the timing of parasitemia without an increase in mouse susceptibility. In contrast, in CD8 deficient mice, we observed an inverse relationship between the parasite inoculum and the timing of death. These results suggest that in normal mice CD8(+) T cells became protective earlier, following the accelerated development of parasitemia. The evaluation of specific cytotoxic responses in vivo to three distinct epitopes revealed that increasing the parasite inoculum hastened the expansion of specific CD8(+) cytotoxic T cells following infection. The differentiation and expansion of T. cruzi-specific CD8(+) cytotoxic T cells is in fact dependent on parasite multiplication, as radiation-attenuated parasites were unable to activate these cells. We also observed that, in contrast to most pathogens, the activation process of T. cruzi-specific CD8(+) cytotoxic T cells was dependent on MHC class II restricted CD4(+) T cells. Our results are compatible with our initial hypothesis that the timing of increase in the pathogen load can be a critical parameter governing the kinetics of CD4(+) T cell-dependent expansion of pathogen-specific CD8(+) cytotoxic T cells.

Improved Prediction of Falls in Community-Dwelling Older Adults Through Phase-Dependent Entropy of Daily-Life Walking

PubMed Central

Ihlen, Espen A. F.; van Schooten, Kimberley S.; Bruijn, Sjoerd M.; van Dieën, Jaap H.; Vereijken, Beatrix; Helbostad, Jorunn L.; Pijnappels, Mirjam

2018-01-01

Age and age-related diseases have been suggested to decrease entropy of human gait kinematics, which is thought to make older adults more susceptible to falls. In this study we introduce a new entropy measure, called phase-dependent generalized multiscale entropy (PGME), and test whether this measure improves fall-risk prediction in community-dwelling older adults. PGME can assess phase-dependent changes in the stability of gait dynamics that result from kinematic changes in events such as heel strike and toe-off. PGME was assessed for trunk acceleration of 30 s walking epochs in a re-analysis of 1 week of daily-life activity data from the FARAO study, originally described by van Schooten et al. (2016). The re-analyzed data set contained inertial sensor data from 52 single- and 46 multiple-time prospective fallers in a 6 months follow-up period, and an equal number of non-falling controls matched by age, weight, height, gender, and the use of walking aids. The predictive ability of PGME for falls was assessed using a partial least squares regression. PGME had a superior predictive ability of falls among single-time prospective fallers when compared to the other gait features. The single-time fallers had a higher PGME (p < 0.0001) of their trunk acceleration at 60% of their step cycle when compared with non-fallers. No significant differences were found between PGME of multiple-time fallers and non-fallers, but PGME was found to improve the prediction model of multiple-time fallers when combined with other gait features. These findings suggest that taking into account phase-dependent changes in the stability of the gait dynamics has additional value for predicting falls in older people, especially for single-time prospective fallers. PMID:29556188

Improved Prediction of Falls in Community-Dwelling Older Adults Through Phase-Dependent Entropy of Daily-Life Walking.

PubMed

Ihlen, Espen A F; van Schooten, Kimberley S; Bruijn, Sjoerd M; van Dieën, Jaap H; Vereijken, Beatrix; Helbostad, Jorunn L; Pijnappels, Mirjam

2018-01-01

Age and age-related diseases have been suggested to decrease entropy of human gait kinematics, which is thought to make older adults more susceptible to falls. In this study we introduce a new entropy measure, called phase-dependent generalized multiscale entropy (PGME), and test whether this measure improves fall-risk prediction in community-dwelling older adults. PGME can assess phase-dependent changes in the stability of gait dynamics that result from kinematic changes in events such as heel strike and toe-off. PGME was assessed for trunk acceleration of 30 s walking epochs in a re-analysis of 1 week of daily-life activity data from the FARAO study, originally described by van Schooten et al. (2016). The re-analyzed data set contained inertial sensor data from 52 single- and 46 multiple-time prospective fallers in a 6 months follow-up period, and an equal number of non-falling controls matched by age, weight, height, gender, and the use of walking aids. The predictive ability of PGME for falls was assessed using a partial least squares regression. PGME had a superior predictive ability of falls among single-time prospective fallers when compared to the other gait features. The single-time fallers had a higher PGME ( p < 0.0001) of their trunk acceleration at 60% of their step cycle when compared with non-fallers. No significant differences were found between PGME of multiple-time fallers and non-fallers, but PGME was found to improve the prediction model of multiple-time fallers when combined with other gait features. These findings suggest that taking into account phase-dependent changes in the stability of the gait dynamics has additional value for predicting falls in older people, especially for single-time prospective fallers.

Stereoselective Inhibition of CYP2C19 and CYP3A4 by Fluoxetine and Its Metabolite: Implications for Risk Assessment of Multiple Time-Dependent Inhibitor Systems

PubMed Central

Lutz, Justin D.; VandenBrink, Brooke M.; Babu, Katipudi N.; Nelson, Wendel L.; Kunze, Kent L.

2013-01-01

Recent guidance on drug-drug interaction (DDI) testing recommends evaluation of circulating metabolites. However, there is little consensus on how to quantitatively predict and/or assess the risk of in vivo DDIs by multiple time-dependent inhibitors (TDIs) including metabolites from in vitro data. Fluoxetine was chosen as the model drug to evaluate the role of TDI metabolites in DDI prediction because it is a TDI of both CYP3A4 and CYP2C19 with a circulating N-dealkylated inhibitory metabolite, norfluoxetine. In pooled human liver microsomes, both enantiomers of fluoxetine and norfluoxetine were TDIs of CYP2C19, (S)-norfluoxetine was the most potent inhibitor with time-dependent inhibition affinity constant (KI) of 7 μM, and apparent maximum time-dependent inhibition rate (kinact,app) of 0.059 min−1. Only (S)-fluoxetine and (R)-norfluoxetine were TDIs of CYP3A4, with (R)-norfluoxetine being the most potent (KI = 8 μM, and kinact,app = 0.011 min−1). Based on in-vitro-to-in-vivo predictions, (S)-norfluoxetine plays the most important role in in vivo CYP2C19 DDIs, whereas (R)-norfluoxetine is most important in CYP3A4 DDIs. Comparison of two multiple TDI prediction models demonstrated significant differences between them in in-vitro-to-in-vitro predictions but not in in-vitro-to-in-vivo predictions. Inclusion of all four inhibitors predicted an in vivo decrease in CYP2C19 (95%) and CYP3A4 (60–62%) activity. The results of this study suggest that adequate worst-case risk assessment for in vivo DDIs by multiple TDI systems can be achieved by incorporating time-dependent inhibition by both parent and metabolite via simple addition of the in vivo time-dependent inhibition rate/cytochrome P450 degradation rate constant (λ/kdeg) values, but quantitative DDI predictions will require a more thorough understanding of TDI mechanisms. PMID:23785064

Inward transport of a toroidally confined plasma subject to strong radial electric fields

NASA Technical Reports Server (NTRS)

Roth, J. R.; Krawczonek, W. M.; Powers, E. J.; Hong, J.; Kim, Y. H.

1977-01-01

Digitally implemented spectral analysis techniques were used to investigate the frequency-dependent fluctuation-induced particle transport across a toroidal magnetic field. When the electric field pointed radially inward, the transport was inward and a significant enhancement of the plasma density and confinement time resulted.

Bats track and exploit changes in insect pest populations

USDA-ARS?s Scientific Manuscript database

The role of bats or any generalist predator in suppressing prey populations depends on the predator’s ability to exploit available prey in space and time. Using a qPCR faecal DNA assay, we document significant association between numbers of Brazilian free-tailed bats (Tadarida brasiliensis) consumin...

Dose-dependency of dexamethasone on the analgesic effect of interscalene block for arthroscopic shoulder surgery using ropivacaine 0.5%: A randomised controlled trial.

PubMed

Woo, Jae Hee; Kim, Youn Jin; Kim, Dong Yeon; Cho, Sooyoung

2015-09-01

Dexamethasone prolongs the duration of single-shot interscalene brachial plexus block (SISB). However, dose-dependency of dexamethasone as an adjuvant for SISB remains insufficiently understood. The objective of this study is to evaluate the effect of different doses of dexamethasone on the duration of SISB using ropivacaine 0.5%. A randomised, double-blind controlled trial. Single university tertiary care centre. One hundred and forty-four patients scheduled for elective arthroscopic shoulder surgery were allocated randomly to one of four groups. Patients received 12 ml of ropivacaine 0.5% in 0.9% saline (control group), or containing dexamethasone 2.5, 5.0 or 7.5 mg for SISB. The primary endpoint was the time to the first analgesic request. Pain scores and adverse effects were also assessed up to 48 h postoperatively. Inclusion of dexamethasone 2.5, 5.0 and 7.5 mg resulted in significant (P < 0.001) increases in time to the first analgesic request by factors of 1.6, 2.2 and 1.8, respectively. The percentages of patients not requiring analgesics in the first 48 h postoperatively with dexamethasone 0.0, 2.5, 5.0 and 7.5 mg were 3, 22, 39 and 33%, respectively (P < 0.001). There were no significant effects on pain scores or incidences of adverse effects. Dexamethasone demonstrated significant beneficial dose-dependent effects on duration to the first analgesic request, the number of patients not requiring analgesics and analgesic use in the first 48 h after SISB for arthroscopic shoulder surgery. There were no significant effects on pain scores or incidences of adverse effects. the trial was registered with the Clinical Trial Registry of Korea: https://cris.nih.go.kr/cris/index.jsp. Identifier: KCT0001078.

Rapid Fuel Quality Surveillance Through Chemometric Modeling of Near-Infrared Spectra

DTIC Science & Technology

2009-01-01

measurements also have a first order advantage and are not time-dependent as is the case for chromatography. Thus, the data preprocessing requirements, while...due in part to the nature of hydrocarbon fuels, which imposes significant technical challenges that must be overcome, and in many cases , traditional...properties. The statistical significance of some other fuel properties is given in Table 2. Note also that in those cases where the property models

Dynamics of threading dislocations in porous heteroepitaxial GaN films

NASA Astrophysics Data System (ADS)

Gutkin, M. Yu.; Rzhavtsev, E. A.

2017-12-01

Behavior of threading dislocations in porous heteroepitaxial gallium nitride (GaN) films has been studied using computer simulation by the two-dimensional discrete dislocation dynamics approach. A computational scheme, where pores are modeled as cross sections of cylindrical cavities, elastically interacting with unidirectional parallel edge dislocations, which imitate threading dislocations, is used. Time dependences of coordinates and velocities of each dislocation from dislocation ensembles under investigation are obtained. Visualization of current structure of dislocation ensemble is performed in the form of a location map of dislocations at any time. It has been shown that the density of appearing dislocation structures significantly depends on the ratio of area of a pore cross section to area of the simulation region. In particular, increasing the portion of pores surface on the layer surface up to 2% should lead to about a 1.5-times decrease of the final density of threading dislocations, and increase of this portion up to 15% should lead to approximately a 4.5-times decrease of it.

Extreme-ultraviolet-initiated high-order harmonic generation in Ar+

NASA Astrophysics Data System (ADS)

Clarke, D. D. A.; van der Hart, H. W.; Brown, A. C.

2018-02-01

We employ the R matrix with time dependence method to investigate extreme-ultraviolet-initiated high-order harmonic generation (XIHHG) in Ar+. Using a combination of extreme-ultraviolet (XUV, 92 nm, 3 ×1012W cm-2 ) and time-delayed, infrared (IR, 800 nm, 3 ×1014W cm-2 ) laser pulses, we demonstrate that control over both the mechanism and timing of ionization can afford significant enhancements in the yield of plateau and subthreshold harmonics alike. The presence of the XUV pulse is also shown to alter the relative contribution of different electron emission pathways. Manifestation of the Ar+ electronic structure is found in the appearance of a pronounced Cooper minimum. Interferences among the outer-valence 3 p and inner-valence 3 s electrons are found to incur only a minor suppression of the harmonic intensities, at least for the present combination of XUV and IR laser light. Additionally, the dependence of the XIHHG efficiency on time delay is discussed and rationalized with the aid of classical trajectory simulations.

Formal methods for dependable real-time systems

NASA Technical Reports Server (NTRS)

Rushby, John

1993-01-01

The motivation for using formal methods to specify and reason about real time properties is outlined and approaches that were proposed and used are sketched. The formal verifications of clock synchronization algorithms are concluded as showing that mechanically supported reasoning about complex real time behavior is feasible. However, there was significant increase in the effectiveness of verification systems since those verifications were performed, at it is to be expected that verifications of comparable difficulty will become fairly routine. The current challenge lies in developing perspicuous and economical approaches to the formalization and specification of real time properties.

Feedback Inhibition Shapes Emergent Computational Properties of Cortical Microcircuit Motifs.

PubMed

Jonke, Zeno; Legenstein, Robert; Habenschuss, Stefan; Maass, Wolfgang

2017-08-30

Cortical microcircuits are very complex networks, but they are composed of a relatively small number of stereotypical motifs. Hence, one strategy for throwing light on the computational function of cortical microcircuits is to analyze emergent computational properties of these stereotypical microcircuit motifs. We are addressing here the question how spike timing-dependent plasticity shapes the computational properties of one motif that has frequently been studied experimentally: interconnected populations of pyramidal cells and parvalbumin-positive inhibitory cells in layer 2/3. Experimental studies suggest that these inhibitory neurons exert some form of divisive inhibition on the pyramidal cells. We show that this data-based form of feedback inhibition, which is softer than that of winner-take-all models that are commonly considered in theoretical analyses, contributes to the emergence of an important computational function through spike timing-dependent plasticity: The capability to disentangle superimposed firing patterns in upstream networks, and to represent their information content through a sparse assembly code. SIGNIFICANCE STATEMENT We analyze emergent computational properties of a ubiquitous cortical microcircuit motif: populations of pyramidal cells that are densely interconnected with inhibitory neurons. Simulations of this model predict that sparse assembly codes emerge in this microcircuit motif under spike timing-dependent plasticity. Furthermore, we show that different assemblies will represent different hidden sources of upstream firing activity. Hence, we propose that spike timing-dependent plasticity enables this microcircuit motif to perform a fundamental computational operation on neural activity patterns. Copyright © 2017 the authors 0270-6474/17/378511-13$15.00/0.

Differential response of peripheral arterial compliance-related indices to a vasoconstrictive stimulus.

PubMed

Guerrisi, Maria; Vannucci, Italo; Toschi, Nicola

2009-01-01

Peripheral arterial elastic properties are greatly affected by cardiovascular as well as other pathologies, and their assessment can provide useful diagnostic indicators. The photoplethysmographic technique can provide finger blood volume and pressure waveforms non-invasively, which can then be processed statically or beat-to-beat to characterize parameters of the vessel wall mechanics. We employ an occlusion-deflation protocol in 48 healthy volunteers to study peripheral artery compliance-related indices over positive and negative transmural pressure values as well as under the influence of a valid vasoconstrictor (cigarette smoking). We calculate beat-to-beat indices (compliance index CI, distensibility index DI, three viscoelastic model parameters (compliance C, viscosity R and inertia L), pressure-volume loop areas A and damping factor DF as well as symmetrical (C(max)) and asymmetrical (C(A)(max)) static compliance estimates, and their distributions over transmural pressure. All distributions are bell-shaped and centred on negative transmural pressure values. Distribution heights were significantly lower in the smoking group (w.r.t. the non-smoking group) for C, CI, DI and significantly higher in R and DF. The estimated volume signal time lag was also significantly lower in the smoking group. Left and right distribution widths were significantly different in all parameters/groups but DI (both groups), C(A)(max), A (smoking group) and L (non-smoking group), and positions of maxima/minima were significantly altered in C(A)(max), R and DF. C, DF and CI are seen to be most sensitive under this protocol, while C(max) and C(A)(max) are seen to be insensitive. These quantities provide complementary, time- and transmural pressure-dependent information about arterial wall mechanics, and the choice of index should depend on the physiological conditions at hand as well as relevant time resolution and transmural pressure range.

Electron-temperature dependence of dissociative recombination of electrons with CO/+/./CO/n-series ions

NASA Technical Reports Server (NTRS)

Whitaker, M.; Biondi, M. A.; Johnsen, R.

1981-01-01

The dependence on electron temperature of the coefficients for electron recombination with molecular cluster ions of the carbon monoxide series, CO(+).(CO)n, is determined. A microwave discharge lasting approximately 0.1 msec was applied in 5-20 Torr neon containing a few tenths percent CO in an afterglow mass spectrometer apparatus, and the time histories of the various afterglow ions were measured. Expressions for the dependence of the recombination coefficients of the dimer and trimer ions CO(+).CO and CO(+).(CO)2 are obtained which are found to be significantly different from those previously obtained for hydronium and ammonium series polar cluster ions, but similar to those of simple diatomic ions.

Deriving inertial wave characteristics from surface drifter velocities - Frequency variability in the tropical Pacific

NASA Technical Reports Server (NTRS)

Poulain, Pierre-Marie; Luther, Douglas S.; Patzert, William C.

1992-01-01

Two techniques were developed for estimating statistics of inertial oscillations from satellite-tracked drifters that overcome the difficulties inherent in estimating such statistics from data dependent upon space coordinates that are a function of time. Application of these techniques to tropical surface drifter data collected during the NORPAX, EPOCS, and TOGA programs reveals a latitude-dependent, statistically significant 'blue shift' of inertial wave frequency. The latitudinal dependence of the blue shift is similar to predictions based on 'global' internal-wave spectral models, with a superposition of frequency shifting due to modification of the effective local inertial frequency by the presence of strongly sheared zonal mean currents within 12 deg of the equator.

A Polarization-Dependent Normal Incident Quantum Cascade Detector Enhanced Via Metamaterial Resonators.

PubMed

Wang, Lei; Zhai, Shen-Qiang; Wang, Feng-Jiao; Liu, Jun-Qi; Liu, Shu-Man; Zhuo, Ning; Zhang, Chuan-Jin; Wang, Li-Jun; Liu, Feng-Qi; Wang, Zhan-Guo

2016-12-01

The design, fabrication, and characterization of a polarization-dependent normal incident quantum cascade detector coupled via complementary split-ring metamaterial resonators in the infrared regime are presented. The metamaterial structure is designed through three-dimensional finite-difference time-domain method and fabricated on the top metal contact, which forms a double-metal waveguide together with the metallic ground plane. With normal incidence, significant enhancements of photocurrent response are obtained at the metamaterial resonances compared with the 45° polished edge coupling device. The photocurrent response enhancements exhibit clearly polarization dependence, and the largest response enhancement factor of 165% is gained for the incident light polarized parallel to the split-ring gap.

Comparison of pulsar positions from timing and very long baseline astrometry

NASA Astrophysics Data System (ADS)

Wang, J. B.; Coles, W. A.; Hobbs, G.; Shannon, R. M.; Manchester, R. N.; Kerr, M.; Yuan, J. P.; Wang, N.; Bailes, M.; Bhat, N. D. R.; Dai, S.; Dempsey, J.; Keith, M. J.; Lasky, P. D.; Levin, Y.; Osłowski, S.; Ravi, V.; Reardon, D. J.; Rosado, P. A.; Russell, C. J.; Spiewak, R.; van Straten, W.; Toomey, L.; Wen, L.; You, X.-P.; Zhu, X.-J.

2017-07-01

Pulsar positions can be measured with high precision using both pulsar timing methods and very long baseline interferometry (VLBI). Pulsar timing positions are referenced to a solar-system ephemeris, whereas VLBI positions are referenced to distant quasars. Here, we compare pulsar positions from published VLBI measurements with those obtained from pulsar timing data from the Nanshan and Parkes radio telescopes in order to relate the two reference frames. We find that the timing positions differ significantly from the VLBI positions (and also differ between different ephemerides). A statistically significant change in the obliquity of the ecliptic of 2.16 ± 0.33 mas is found for the JPL ephemeris DE405, but no significant rotation is found in subsequent JPL ephemerides. The accuracy with which we can relate the two frames is limited by the current uncertainties in the VLBI reference source positions and in matching the pulsars to their reference source. Not only do the timing positions depend on the ephemeris used in computing them, but also different segments of the timing data lead to varying position estimates. These variations are mostly common to all ephemerides, but slight changes are seen at the 10 μas level between ephemerides.

Time dependent loss of trabecular bone in human tibial plateau fractures.

PubMed

Solomon, Lucian Bogdan; Kitchen, David; Anderson, Paul Hamill; Yang, Dongqing; Starczak, Yolandi; Kogawa, Masakazu; Perilli, Egon; Smitham, Peter Jonathan; Rickman, Mark Sean; Thewlis, Dominic; Atkins, Gerald James

2018-05-22

We investigated if time between injury and surgery affects cancellous bone properties in patients suffering tibial plateau fractures (TPF), in terms of structural integrity and gene expression controlling bone loss. A cohort of 29 TPF, operated 1-17 days post-injury, had biopsies from the fracture and an equivalent contralateral limb site, at surgery. Samples were assessed using micro-computed tomography and real-time RT-PCR analysis for the expression of genes known to be involved in bone remodeling and fracture healing. Significant decreases in the injured vs control side were observed for bone volume fraction (BV/TV, -13.5 ± 6.0%, p = 0.011), trabecular number (Tb.N, -10.5 ± 5.9%, p = 0.041) and trabecular thickness (Tb.Th, -4.6 ± 2.5%, p = 0.033). Changes in these parameters were more evident in patients operated 5-17 days post-injury, compared to those operated in the first 4 days post injury. A significant negative association was found between Tb.Th (r = -0.54, p < 0.01) and BV/TV (r = -0.39, p < 0.05) in relation to time post-injury in the injured limb. Both BV/TV and Tb.Th were negatively associated with expression of key molecular markers of bone resorption, CTSK, ACP5 and the ratio of RANKL:OPG mRNA. These structure/gene expression relationships did not exist in the contralateral tibial plateau of these patients. This study demonstrated that there is a significant early time-dependent bone loss in the proximal tibia after TPF. This bone loss was significantly associated with altered expression of genes typically involved in the process of osteoclastic bone resorption but possibly also by osteocytes. The mechanism of early bone loss in such fractures should be a subject of further investigation. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Fibrinolytic Activity and Dose-Dependent Effect of Incubating Human Blood Clots in Caffeic Acid Phenethyl Ester: In Vitro Assays

PubMed Central

Elnager, Abuzar; Hassan, Rosline; Idris, Zamzuri; Mustafa, Zulkifli; Wan-Arfah, Nadiah; Sulaiman, S. A.; Gan, Siew Hua; Abdullah, Wan Zaidah

2015-01-01

Background. Caffeic acid phenethyl ester (CAPE) has been reported to possess time-dependent fibrinolytic activity by in vitro assay. This study is aimed at investigating fibrinolytic dose-dependent activity of CAPE using in vitro assays. Methods. Standardized human whole blood (WB) clots were incubated in either blank controls or different concentrations of CAPE (3.75, 7.50, 15.00, 22.50, and 30.00 mM). After 3 hours, D-dimer (DD) levels and WB clot weights were measured for each concentration. Thromboelastography (TEG) parameters were recorded following CAPE incubation, and fibrin morphology was examined under a confocal microscope. Results. Overall, mean DD (μg/mL) levels were significantly different across samples incubated with different CAPE concentrations, and the median pre- and postincubation WB clot weights (grams) were significantly decreased for each CAPE concentration. Fibrin removal was observed microscopically and indicated dose-dependent effects. Based on the TEG test, the Ly30 fibrinolytic parameter was significantly different between samples incubated with two different CAPE concentrations (15.0 and 22.50 mM). The 50% effective dose (ED50) of CAPE (based on DD) was 1.99 mg/mL. Conclusions. This study suggests that CAPE possesses fibrinolytic activity following in vitro incubation and that it has dose-dependent activities. Therefore, further investigation into CAPE as a potential alternative thrombolytic agent should be conducted. PMID:25664321

Cell Specific Cytotoxicity and Uptake of Graphene Nanoribbons

PubMed Central

Chowdhury, Sayan Mullick; Lalwani, Gaurav; Zhang, Kevin; Yang, Jeong Yun; Neville, Kayla; Sitharaman, Balaji

2012-01-01

The synthesis of oxidized graphene nanoribbons (O-GNR) via longitudinal unzipping of carbon nanotubes opens avenues for their further development for a variety of biomedical applications. Evaluation of the cyto- and bio-compatibility is necessary to develop any new material for in vivo biomedical applications. In this study, we report the cytotoxicity screening of O-GNRs water-solubilized with PEG-DSPE (1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethylene glycol)]), using six different assays, in four representative cell lines; Henrietta Lacks cells (HeLa) derived from cervical cancer tissue, National Institute of Health 3T3 mouse fibroblast cells (NIH-3T3), Sloan Kettering breast cancer cells (SKBR3) and Michigan cancer foundation-7 breast cancer cells (MCF7). These cell lines significantly differed in their response to O-GNR-PEG-DSPE formulations; assessed and evaluated using various endpoints (lactate dehydrogenase (LDH) release, cellular metabolism, lysosomal integrity and cell proliferation) for cytotoxicity. In general, all the cells showed a dose-dependent (10–400 μg/ml) and time-dependent (12–48 h) decrease in cell viability. However, the degree of cytotoxicity was significantly lower in MCF7 or SKBR3 cells compared to HeLa cells. These cells were 100% viable upto 48 hours, when incubated at 10μg/ml O-GNR-PEG-DSPE concentration, and showed decrease in cell viability above this concentration with ~78% of cells viable at the highest concentration (400 μg/ml). In contrast, significant cell death (5–25% cell death depending on the time point, and the assay) was observed for HeLa cells even at a low concentration of 10μg/ml. The decrease in cell viability was steep with increase in concentration with the CD50 values ≥ 100μg/ml depending on the assay, and time point. Transmission electron microscopy of the various cells treated with the O-GNR solutions show higher uptake of the O-GNR-PEG-DSPEs into HeLa cells compared to other cell types. Additional analysis indicates that this increased uptake is the dominant cause of the significantly higher toxicity exhibited by HeLa cells. The results suggest that water-solubilized O-GNR-PEG-DSPEs have a heterogeneous cell-specific cytotoxicity, and have significantly different cytotoxicity profile compared to graphene nanoparticles prepared by the modified Hummer’s method (graphene nanoparticles prepared by oxidation of graphite, and its mechanical exfoliation) or its variations. PMID:23072942

Cell specific cytotoxicity and uptake of graphene nanoribbons.

PubMed

Mullick Chowdhury, Sayan; Lalwani, Gaurav; Zhang, Kevin; Yang, Jeong Y; Neville, Kayla; Sitharaman, Balaji

2013-01-01

The synthesis of oxidized graphene nanoribbons (O-GNR) via longitudinal unzipping of carbon nanotubes opens avenues for their further development for a variety of biomedical applications. Evaluation of the cyto- and bio-compatibility is necessary to develop any new material for in vivo biomedical applications. In this study, we report the cytotoxicity screening of O-GNRs water-solubilized with PEG-DSPE (1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethylene glycol)]), using six different assays, in four representative cell lines; Henrietta Lacks cells (HeLa) derived from cervical cancer tissue, National Institute of Health 3T3 mouse fibroblast cells (NIH-3T3), Sloan Kettering breast cancer cells (SKBR3) and Michigan cancer foundation-7 breast cancer cells (MCF7). These cell lines significantly differed in their response to O-GNR-PEG-DSPE formulations; assessed and evaluated using various endpoints (lactate dehydrogenase (LDH) release, cellular metabolism, lysosomal integrity and cell proliferation) for cytotoxicity. In general, all the cells showed a dose-dependent (10-400 μg/ml) and time-dependent (12-48 h) decrease in cell viability. However, the degree of cytotoxicity was significantly lower in MCF7 or SKBR3 cells compared to HeLa cells. These cells were 100% viable upto 48 h, when incubated at 10 μg/ml O-GNR-PEG-DSPE concentration, and showed decrease in cell viability above this concentration with ~78% of cells viable at the highest concentration (400 μg/ml). In contrast, significant cell death (5-25% cell death depending on the time point, and the assay) was observed for HeLa cells even at a low concentration of 10 μg/ml. The decrease in cell viability was steep with increase in concentration with the CD(50) values ≥ 100 μg/ml depending on the assay, and time point. Transmission electron microscopy of the various cells treated with the O-GNR solutions show higher uptake of the O-GNR-PEG-DSPEs into HeLa cells compared to other cell types. Additional analysis indicates that this increased uptake is the dominant cause of the significantly higher toxicity exhibited by HeLa cells. The results suggest that water-solubilized O-GNR-PEG-DSPEs have a heterogenous cell-specific cytotoxicity, and have significantly different cytotoxicity profile compared to graphene nanoparticles prepared by the modified Hummer's method (graphene nanoparticles prepared by oxidation of graphite, and its mechanical exfoliation) or its variations. Copyright © 2012 Elsevier Ltd. All rights reserved.

Serum biomarkers for acute hepatotoxicity of Echis pyramidum snake venom in rats.

PubMed

Asmari, Abdulrahman K Al; Khan, Haseeb A; Banah, Faisal A; Buraidi, Ahmed A Al; Manthiri, Rajamohammed A

2015-01-01

Echis pyramidum is a venomous viper responsible for most cases of envenomation in Arabian Peninsula. We determined the acute phase (3-6 h) changes in serum markers of liver function including alanine aminotransferase (ALT), alkaline phosphatase (ALP), gamma glutamyl transferase (GGT) and bilirubin in adult male Sprague Dawley rats injected with Echis pyramidum venom (EPV) in the doses of 0.00 (control), 0.25, 0.50 and 1.00 mg/kg bodyweight. We also analyzed markers of oxidative stress including superoxide dismutase (SOD), catalase (CAT), total thiols (T-SH) and thiobarbituric acids reactive substances (TBARS) in liver. The results showed significant and dose- and time-dependent increases in serum ALT, ALP and GGT activities after a single injection of EPV. Serum bilirubin was significantly increased by medium and high doses of EVP after 3 h post-injection and then decreased at 6 h. The low dose of EPV neither affected the activity of SOD nor altered the levels of liver T-SH and TBARS, however, it significantly decreased the activity of CAT at 6 h post-injection of EPV. The medium dose of EPV significantly reduced liver SOD activity after 6 h whereas the high dose significantly reduced the SOD activity at 3 h and 6 h post-dosing. Both medium and high doses of EPV caused significant as well as dose- and time-dependent reductions in liver CAT activities. The high dose significantly reduced T-SH and increased TBARS in rat liver. Further studies are warranted to test the pharmacological potential of early phase antioxidant therapy for neutralizing the toxic effects of EPV.

Modeling hole transport in wet and dry DNA.

PubMed

Pavanello, Michele; Adamowicz, Ludwik; Volobuyev, Maksym; Mennucci, Benedetta

2010-04-08

We present a DFT/classical molecular dynamics model of DNA charge conductivity. The model involves a temperature-driven, hole-hopping charge transfer and includes the time-dependent nonequilibrium interaction of DNA with its molecular environment. We validate our method against a variety of hole transport experiments. The method predicts a significant hole-transfer slowdown of approximately 35% from dry to wet DNA with and without electric field bias. In addition, in agreement with experiments, it also predicts an insulating behavior of (GC)(N) oligomers for 40 < N < 1000, depending on the experimental setup.

Polarization-dependent diffraction in all-dielectric, twisted-band structures

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

Kardaś, Tomasz M.; Jagodnicka, Anna; Wasylczyk, Piotr, E-mail: pwasylcz@fuw.edu.pl

2015-11-23

We propose a concept for light polarization management: polarization-dependent diffraction in all-dielectric microstructures. Numerical simulations of light propagation show that with an appropriately configured array of twisted bands, such structures may exhibit zero birefringence and at the same time diffract two circular polarizations with different efficiencies. Non-birefringent structures as thin as 3 μm have a significant difference in diffraction efficiency for left- and right-hand circular polarizations. We identify the structural parameters of such twisted-band matrices for optimum performance as circular polarizers.

Acceleration techniques for dependability simulation. M.S. Thesis

NASA Technical Reports Server (NTRS)

Barnette, James David

1995-01-01

As computer systems increase in complexity, the need to project system performance from the earliest design and development stages increases. We have to employ simulation for detailed dependability studies of large systems. However, as the complexity of the simulation model increases, the time required to obtain statistically significant results also increases. This paper discusses an approach that is application independent and can be readily applied to any process-based simulation model. Topics include background on classical discrete event simulation and techniques for random variate generation and statistics gathering to support simulation.

Heavy quark energy loss in nuclear medium

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

Zhang, Benr-Wei; Wang, Enke; Wang, Xin-Nian

2003-09-16

Multiple scattering, modified fragmentation functions and radiative energy loss of a heavy quark propagating in a nuclear medium are investigated in perturbative QCD. Because of the quark mass dependence of the gluon formation time, the medium size dependence of heavy quark energy loss is found to change from a linear to a quadratic form when the initial energy and momentum scale are increased relative to the quark mass. The radiative energy loss is also significantly suppressed relative to a light quark due to the suppression of collinear gluon emission by a heavy quark.

Theoretical and Experimental Investigations on Droplet Evaporation and Droplet Ignition at High Pressures

NASA Technical Reports Server (NTRS)

Ristau, R.; Nagel, U.; Iglseder, H.; Koenig, J.; Rath, H. J.; Normura, H.; Kono, M.; Tanabe, M.; Sato, J.

1993-01-01

The evaporation of fuel droplets under high ambient pressure and temperature in normal gravity and microgravity has been investigated experimentally. For subcritical ambient conditions, droplet evaporation after a heat-up period follows the d(exp 2)-law. For all data the evaporation constant increases as the ambient temperature increases. At identical ambient conditions the evaporation constant under microgravity is smaller compared to normal gravity. This effect can first be observed at 1 bar and increases with ambient pressure. Preliminary experiments on ignition delay for self-igniting fuel droplets have been performed. Above a 1 s delay time, at identical ambient conditions, significant differences in the results of the normal and microgravity data are observed. Self-ignition occurs within different temperature ranges due to the influence of gravity. The time dependent behavior of the droplet is examined theoretically. In the calculations two different approaches for the gas phase are applied. In the first approach the conditions at the interface are given using a quasi steady theory approximation. The second approach uses a set of time dependent governing equations for the gas phase which are then evaluated. In comparison, the second model shows a better agreement with the drop tower experiments. In both cases a time dependent gasification rate is observed.

Quiet eye training improves surgical knot tying more than traditional technical training: a randomized controlled study.

PubMed

Causer, Joe; Harvey, Adrian; Snelgrove, Ryan; Arsenault, Gina; Vickers, Joan N

2014-08-01

We examined the effectiveness of technical training (TT) and quiet eye training (QE) on the performance of one-handed square knot tying in surgical residents. Twenty surgical residents were randomly assigned to the 2 groups and completed pretest, training, retention, and transfer tests. Participants wore a mobile eye tracker that simultaneously recorded their gaze and hand movements. Dependent variables were knot tying performance (%), QE duration (%), number of fixations, total movement time (s), and hand movement phase time (s). The QE training group had significantly higher performance scores, a longer QE duration, fewer fixations, faster total knot tying times, and faster movement phase times compared with the TT group. The QE group maintained performance in the transfer test, whereas the TT group significantly decreased performance from retention to transfer. QE training significantly improved learning, retention, and transfer of surgical knot tying compared with a traditional technical approach. Both performance effectiveness (performance outcome) and movement efficiency (hand movement times) were improved using QE modeling, instruction, and feedback. Copyright © 2014 Elsevier Inc. All rights reserved.

Convective stirring efficiency in strongly temperature-dependent, infinite Prandtl number fluids: application to planetary mantles.

NASA Astrophysics Data System (ADS)

Tosi, N.; Samuel, H.

2017-12-01

Many rocky planetary bodies currently exhibit solid-state convection, or have experienced this process during their histories.Such a style of convection is characterized by the negligible influence of inertia, and a rheology known to be strongly temperature-dependent. Convective motion within such planetary envelopes determine their ability to preserve or to homogenize compositional heterogeneities.Therefore, understanding the efficiency of convective stirring is key to the interpretation of petrological, geochemical, and cosmochemical data originating on the Earth from sampled erupted lava, or inferred from meteorite analysis (e.g., Mars). In order to study this problem we have conducted series of numerical experiments in 2D and 3D Cartesian domains heated from below and cooled from above. We varied systematically the Rayleigh number and the activation energy using a strongly temperature-dependent viscosity based on the Arrhenius law for diffusion creep. Given the large values of activation energy considered, all our experiments fall into the stagnant lid regime. Stirring efficiency is determined by computing the finite-time Lyapunov exponents, which provide a measure of the Lagrangian deformation.This systematic exploration allows the degree of heterogeneity and its spatial variability to be quantified, and yields mixing times for both 2D and 3D geometries.Our results indicate significant differences between geometries: 2D cases lead more frequently to steady solutions, for which stirring efficiency is spatially heterogeneous and mostly weak. On the other hand, 3D cases show more time dependence of the velocity field and generally yield more efficient convective stirring, even for cases with a weak time-dependence of the flow. Scaling laws for stirring efficiencies are derived, and will serve as a basis to discuss the application to planetary mantles.

Time-resolved confocal fluorescence microscopy: novel technical features and applications for FLIM, FRET and FCS using a sophisticated data acquisition concept in TCSPC

NASA Astrophysics Data System (ADS)

Koberling, Felix; Krämer, Benedikt; Kapusta, Peter; Patting, Matthias; Wahl, Michael; Erdmann, Rainer

2007-05-01

In recent years time-resolved fluorescence measurement and analysis techniques became a standard in single molecule microscopy. However, considering the equipment and experimental implementation they are typically still an add-on and offer only limited possibilities to study the mutual dependencies with common intensity and spectral information. In contrast, we are using a specially designed instrument with an unrestricted photon data acquisition approach which allows to store spatial, temporal, spectral and intensity information in a generalized format preserving the full experimental information. This format allows us not only to easily study dependencies between various fluorescence parameters but also to use, for example, the photon arrival time for sorting and weighting the detected photons to improve the significance in common FCS and FRET analysis schemes. The power of this approach will be demonstrated for different techniques: In FCS experiments the concentration determination accuracy can be easily improved by a simple time-gated photon analysis to suppress the fast decaying background signal. A more detailed analysis of the arrival times allows even to separate FCS curves for species which differ in their fluorescence lifetime but, for example, cannot be distinguished spectrally. In multichromophoric systems like a photonic wire which undergoes unidirectional multistep FRET the lifetime information complements significantly the intensity based analysis and helps to assign the respective FRET partners. Moreover, together with pulsed excitation the time-correlated analysis enables directly to take advantage of alternating multi-colour laser excitation. This pulsed interleaved excitation (PIE) can be used to identify and rule out inactive FRET molecules which cause interfering artefacts in standard FRET efficiency analysis. We used a piezo scanner based confocal microscope with compact picosecond diode lasers as excitation sources. The timing performance can be significantly increased by using new SPAD detectors which enable, in conjunction with new TCSPC electronics, an overall IRF width of less than 120 ps maintaining single molecule sensitivity.

Wave function for time-dependent harmonically confined electrons in a time-dependent electric field.

PubMed

Li, Yu-Qi; Pan, Xiao-Yin; Sahni, Viraht

2013-09-21

The many-body wave function of a system of interacting particles confined by a time-dependent harmonic potential and perturbed by a time-dependent spatially homogeneous electric field is derived via the Feynman path-integral method. The wave function is comprised of a phase factor times the solution to the unperturbed time-dependent Schrödinger equation with the latter being translated by a time-dependent value that satisfies the classical driven equation of motion. The wave function reduces to that of the Harmonic Potential Theorem wave function for the case of the time-independent harmonic confining potential.

Glucocorticoid Repression of Inflammatory Gene Expression Shows Differential Responsiveness by Transactivation- and Transrepression-Dependent Mechanisms

PubMed Central

King, Elizabeth M.; Chivers, Joanna E.; Rider, Christopher F.; Minnich, Anne; Giembycz, Mark A.; Newton, Robert

2013-01-01

Binding of glucocorticoid to the glucocorticoid receptor (GR/NR3C1) may repress inflammatory gene transcription via direct, protein synthesis-independent processes (transrepression), or by activating transcription (transactivation) of multiple anti-inflammatory/repressive factors. Using human pulmonary A549 cells, we showed that 34 out of 39 IL-1β-inducible mRNAs were repressed to varying degrees by the synthetic glucocorticoid, dexamethasone. Whilst these repressive effects were GR-dependent, they did not correlate with either the magnitude of IL-1β-inducibility or the NF-κB-dependence of the inflammatory genes. This suggests that induction by IL-1β and repression by dexamethasone are independent events. Roles for transactivation were investigated using the protein synthesis inhibitor, cycloheximide. However, cycloheximide reduced the IL-1β-dependent expression of 13 mRNAs, which, along with the 5 not showing repression by dexamethasone, were not analysed further. Of the remaining 21 inflammatory mRNAs, cycloheximide significantly attenuated the dexamethasone-dependent repression of 11 mRNAs that also showed a marked time-dependence to their repression. Such effects are consistent with repression occurring via the de novo synthesis of a new product, or products, which subsequently cause repression (i.e., repression via a transactivation mechanism). Conversely, 10 mRNAs showed completely cycloheximide-independent, and time-independent, repression by dexamethasone. This is consistent with direct GR transrepression. Importantly, the inflammatory mRNAs showing attenuated repression by dexamethasone in the presence of cycloheximide also showed a significantly greater extent of repression and a higher potency to dexamethasone compared to those mRNAs showing cycloheximide-independent repression. This suggests that the repression of inflammatory mRNAs by GR transactivation-dependent mechanisms accounts for the greatest levels of repression and the most potent repression by dexamethasone. In conclusion, our data indicate roles for both transrepression and transactivation in the glucocorticoid-dependent repression of inflammatory gene expression. However, transactivation appears to account for the more potent and efficacious mechanism of repression by glucocorticoids on these IL-1β-induced genes. PMID:23349769

Modeling and Measurement of Sustained Loading and Temperature-Dependent Deformation of Carbon Fiber-Reinforced Polymer Bonded to Concrete.

PubMed

Jeong, Yoseok; Lee, Jaeha; Kim, WooSeok

2015-01-29

This paper aims at presenting the effects of short-term sustained load and temperature on time-dependent deformation of carbon fiber-reinforced polymer (CFRP) bonded to concrete and pull-off strength at room temperature after the sustained loading period. The approach involves experimental and numerical analysis. Single-lap shear specimens were used to evaluate temperature and short-term sustained loading effects on time-dependent behavior under sustained loading and debonding behavior under pull-off loading after a sustained loading period. The numerical model was parameterized with experiments on the concrete, FRP, and epoxy. Good correlation was seen between the numerical results and single-lap shear experiments. Sensitivity studies shed light on the influence of temperature, epoxy modulus, and epoxy thickness on the redistribution of interfacial shear stress during sustained loading. This investigation confirms the hypothesis that interfacial stress redistribution can occur due to sustained load and elevated temperature and its effect can be significant.

Associations among hypothalamus-pituitary-adrenal axis function, novelty seeking, and retention in methadone maintenance therapy for heroin dependency.

PubMed

Lin, Shih-Hsien; Chen, Wei Tseng; Chen, Kao Chin; Lee, Sheng-Yu; Lee, I Hui; Chen, Po See; Yeh, Tzung Lieh; Lu, Ru-Band; Yang, Yen Kuang

2013-01-01

The efficacy of methadone maintenance therapy for heroin dependence is compromised by the low retention rate. Hypothalamus-pituitary-adrenal (HPA) axis function, which is associated with stress response, and novelty seeking (NS), a personality trait associated with low dopaminergic activity, may play roles in retention. We conducted a prospective study in which HPA axis function and NS were assessed by the dexamethasone suppression test and the Tridimensional Personality Questionnaire at baseline, respectively. The retention rate was assessed at the half- and 1-year points of methadone maintenance therapy. A low suppression rate of dexamethasone suppression test (D%) was associated with a high level of NS. A low D% was associated with half-year dropout, whereas a high level of NS was associated with 1-year dropout. Survival analysis confirmed that D% and NS were significant time-dependent covariates for retention. The findings showed that HPA axis function and NA were associated with retention at different time points.

A time-dependent model to determine the thermal conductivity of a nanofluid

NASA Astrophysics Data System (ADS)

Myers, T. G.; MacDevette, M. M.; Ribera, H.

2013-07-01

In this paper, we analyse the time-dependent heat equations over a finite domain to determine expressions for the thermal diffusivity and conductivity of a nanofluid (where a nanofluid is a fluid containing nanoparticles with average size below 100 nm). Due to the complexity of the standard mathematical analysis of this problem, we employ a well-known approximate solution technique known as the heat balance integral method. This allows us to derive simple analytical expressions for the thermal properties, which appear to depend primarily on the volume fraction and liquid properties. The model is shown to compare well with experimental data taken from the literature even up to relatively high concentrations and predicts significantly higher values than the Maxwell model for volume fractions approximately >1 %. The results suggest that the difficulty in reproducing the high values of conductivity observed experimentally may stem from the use of a static heat flow model applied over an infinite domain rather than applying a dynamic model over a finite domain.

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

Kaur, Gurpreet; Ly-Huynh, Jennifer D.; Jans, David A., E-mail: David.Jans@monash.edu

Highlights: • High intracellular calcium inhibits Impα/β1- or Impβ1-dependent nuclear protein import. • The effect of Ca{sup 2+} on nuclear import does not relate to changes in the nuclear pore. • High intracellular calcium can result in mislocalisation of Impβ1, Ran and RCC1. - Abstract: We previously showed that increased intracellular calcium can modulate Importin (Imp)β1-dependent nuclear import of SRY-related chromatin remodeling proteins. Here we extend this work to show for the first time that high intracellular calcium inhibits Impα/β1- or Impβ1-dependent nuclear protein import generally. The basis of this relates to the mislocalisation of the transport factors Impβ1 andmore » Ran, which show significantly higher nuclear localization in contrast to various other factors, and RCC1, which shows altered subnuclear localisation. The results here establish for the first time that intracellular calcium modulates conventional nuclear import through direct effects on the nuclear transport machinery.« less

Anisotropic thermal conductivity in carbon honeycomb

NASA Astrophysics Data System (ADS)

Chen, Xue-Kun; Liu, Jun; Du, Dan; Xie, Zhong-Xiang; Chen, Ke-Qiu

2018-04-01

Carbon honeycomb, a new kind of 3D carbon allotrope experimentally synthesized recently, has received much attention for its fascinating applications in electronic device and energy storage. In the present work, we perform equilibrium molecular dynamics (EMD) to study the thermal transport properties of carbon honeycombs with different chirality. It is found that the thermal conductivity along the honeycomb axis ({κx} ) is three times larger than that normal to the axis ({κz} ), which shows strong anisotropy reflecting their geometric anisotropy. Lattice dynamics calculations reveal that this anisotropy stems from the orientation-dependent phonon group velocities. Moreover, when ambient temperature (T ) increases from 200 K to 800 K, the {{T}-1} dependence of κ is observed due to the enhanced Umklapp scattering. The detailed phonon spectra analyses indicate phonon group velocities are insensitive to the variation of ambient temperature, and the temperature dependence of the relaxation times of low-frequency phonons (<20 THz) follows ∼ {{T}-1} behavior. Our results have a certain guiding significance to develop carbon honeycomb for effective thermal channeling devices.

Modeling and Measurement of Sustained Loading and Temperature-Dependent Deformation of Carbon Fiber-Reinforced Polymer Bonded to Concrete

PubMed Central

Jeong, Yoseok; Lee, Jaeha; Kim, WooSeok

2015-01-01

This paper aims at presenting the effects of short-term sustained load and temperature on time-dependent deformation of carbon fiber-reinforced polymer (CFRP) bonded to concrete and pull-off strength at room temperature after the sustained loading period. The approach involves experimental and numerical analysis. Single-lap shear specimens were used to evaluate temperature and short-term sustained loading effects on time-dependent behavior under sustained loading and debonding behavior under pull-off loading after a sustained loading period. The numerical model was parameterized with experiments on the concrete, FRP, and epoxy. Good correlation was seen between the numerical results and single-lap shear experiments. Sensitivity studies shed light on the influence of temperature, epoxy modulus, and epoxy thickness on the redistribution of interfacial shear stress during sustained loading. This investigation confirms the hypothesis that interfacial stress redistribution can occur due to sustained load and elevated temperature and its effect can be significant. PMID:28787948

Magnetic response of a disordered binary ferromagnetic alloy to an oscillating magnetic field

NASA Astrophysics Data System (ADS)

Vatansever, Erol; Polat, Hamza

2015-08-01

By means of Monte Carlo simulation with local spin update Metropolis algorithm, we have elucidated non-equilibrium phase transition properties and stationary-state treatment of a disordered binary ferromagnetic alloy of the type ApB1-p on a square lattice. After a detailed analysis, we have found that the system shows many interesting and unusual thermal and magnetic behaviors, for instance, the locations of dynamic phase transition points change significantly depending upon amplitude and period of the external magnetic field as well as upon the active concentration of A-type components. Much effort has also been dedicated to clarify the hysteresis tools, such as coercivity, dynamic loop area as well as dynamic correlations between time dependent magnetizations and external time dependent applied field as a functions of period and amplitude of field as well as active concentration of A-type components, and outstanding physical findings have been reported in order to better understand the dynamic process underlying present system.

Time-dependent reversal of significant intrapulmonary shunt after liver transplantation.

PubMed

Jin, Xin; Sun, Byung Joo; Song, Jae-Kwan; Roh, Jae-Hyung; Jang, Jeong Yoon; Kim, Dae-Hee; Lim, Young-Suk; Song, Jong-Min; Kang, Duk-Hyun; Lee, Sung Gyu

2018-03-05

Although the association between intrapulmonary shunt (IPS) and liver cirrhosis is clear, data of repeated contrast echocardiography (CE) before and after liver transplantation (LT) to evaluate factors associated with IPS are limited. Hand-agitated saline was used for CE and, by assessing left-chamber opacification, IPS was classified as grade 0 to 4. Grade 3/4 constituted significant IPS and hepatopulmonary syndrome (HPS) was defined as significant IPS with the arterial partial pressure of oxygen < 70 mmHg. Before LT, 253 patients underwent CE and the frequency of significant IPS and HPS were 44% (n = 112) and 7% (n = 17), respectively. Child-Pugh score (odds ratio [OR], 1.345; 95% confidence interval [CI], 1.090 to 1.660; p = 0.006) and arterial oxygen content (OR, 0.838; 95% CI, 0.708 to 0.991; p = 0.039) were independent determinants of significant IPS, whereas direct bilirubin (OR, 1.076; 95% CI, 1.012 to 1.144; p = 0.019) was the only variable associated with HPS. Among 153 patients who underwent successful LT, repeated CE was performed in 97 (63%), which showed significant reductions in IPS grade (from 2.6 ± 1.0 to 1.2 ± 1.3, p < 0.001) and the prevalence of significant IPS (from 56% to 20%, p = 0.038). After adjustment for pre-LT IPS grade, time from LT to repeated CE presented negative linear relationship with post-LT IPS grade (r 2 = 0.366, p < 0.001) and was the only determinant of post-LT IPS grade (OR, 1.009; 95% CI, 1.003 to 1.014; p = 0.004). Repeated CE is useful to evaluate intrapulmonary vascular change before and after LT. Reversal of IPS after successful LT is time-dependent and follow-up duration should be considered for accurate assessment of IPS after LT.

Effect of beta-hydroxy-beta-methylglutaryl coenzyme A reductase inhibitors and antioxidant vitamins on free radical lipid oxidation in rat liver.

PubMed

Lankin, V Z; Ivanova, M V; Konovalova, G G; Tikhaze, A K; Kaminnyi, A I; Kukharchuk, V V

2007-04-01

We studied the effects of two inhibitors of beta-hydroxy-beta-methylglutaryl coenzyme A reductase, simvastatin and lovastatin, on the lag phase of ascorbate-dependent lipid oxidation in rat liver. Oxidizability of liver biological membranes significantly increased in intact animals and rats with induced hypercholesterolemia after peroral administration of these statins. The lag phase of ascorbate-dependent lipid oxidation in liver biomembranes decreased by 2.1 times in hypercholesterolemic rats. In animals of the lovastatin group this parameter decreased by 4.4 times compared to the control. In intact rats receiving simvastatin, the lag phase of oxidation in biomembranes from the liver decreased practically by 2 times. At the same time, in animals receiving simvastatin in combination with antioxidant vitamins (vitamins E and C, provitamin A) and selenium, the period of induction of oxidation increased by 3.3 times. Our results indicate that beta-hydroxy-beta-methylglutaryl coenzyme A reductase inhibitors produce a prooxidant effect on the liver, which can be prevented by administration of antioxidant agents.

Linear and nonlinear trending and prediction for AVHRR time series data

NASA Technical Reports Server (NTRS)

Smid, J.; Volf, P.; Slama, M.; Palus, M.

1995-01-01

The variability of AVHRR calibration coefficient in time was analyzed using algorithms of linear and non-linear time series analysis. Specifically we have used the spline trend modeling, autoregressive process analysis, incremental neural network learning algorithm and redundancy functional testing. The analysis performed on available AVHRR data sets revealed that (1) the calibration data have nonlinear dependencies, (2) the calibration data depend strongly on the target temperature, (3) both calibration coefficients and the temperature time series can be modeled, in the first approximation, as autonomous dynamical systems, (4) the high frequency residuals of the analyzed data sets can be best modeled as an autoregressive process of the 10th degree. We have dealt with a nonlinear identification problem and the problem of noise filtering (data smoothing). The system identification and filtering are significant problems for AVHRR data sets. The algorithms outlined in this study can be used for the future EOS missions. Prediction and smoothing algorithms for time series of calibration data provide a functional characterization of the data. Those algorithms can be particularly useful when calibration data are incomplete or sparse.

Choice of reference measurements affects quantification of long diffusion time behaviour using stimulated echoes.

PubMed

Kleinnijenhuis, Michiel; Mollink, Jeroen; Lam, Wilfred W; Kinchesh, Paul; Khrapitchev, Alexandre A; Smart, Sean C; Jbabdi, Saad; Miller, Karla L

2018-02-01

To demonstrate how reference data affect the quantification of the apparent diffusion coefficient (ADC) in long diffusion time measurements with diffusion-weighted stimulated echo acquisition mode (DW-STEAM) measurements, and to present a modification to avoid contribution from crusher gradients in DW-STEAM. For DW-STEAM, reference measurements at long diffusion times have significant b 0 value, because b = 0 cannot be achieved in practice as a result of the need for signal spoiling. Two strategies for acquiring reference data over a range of diffusion times were considered: constant diffusion weighting (fixed-b 0 ) and constant gradient area (fixed-q 0 ). Fixed-b 0 and fixed-q 0 were compared using signal calculations for systems with one and two diffusion coefficients, and experimentally using data from postmortem human corpus callosum samples. Calculations of biexponential diffusion decay show that the ADC is underestimated for reference images with b > 0, which can induce an apparent time-dependence for fixed-q 0 . Restricted systems were also found to be affected. Experimentally, the exaggeration of the diffusion time-dependent effect under fixed-q 0 versus fixed-b 0 was in a range predicted theoretically, accounting for 62% (longitudinal) and 35% (radial) of the time dependence observed in white matter. Variation in the b-value of reference measurements in DW-STEAM can induce artificial diffusion time dependence in ADC, even in the absence of restriction. Magn Reson Med 79:952-959, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine.

Spatio-temporal analysis of the electron power absorption in electropositive capacitive RF plasmas based on moments of the Boltzmann equation

NASA Astrophysics Data System (ADS)

Schulze, J.; Donkó, Z.; Lafleur, T.; Wilczek, S.; Brinkmann, R. P.

2018-05-01

Power absorption by electrons from the space- and time-dependent electric field represents the basic sustaining mechanism of all radio-frequency driven plasmas. This complex phenomenon has attracted significant attention. However, most theories and models are, so far, only able to account for part of the relevant mechanisms. The aim of this work is to present an in-depth analysis of the power absorption by electrons, via the use of a moment analysis of the Boltzmann equation without any ad-hoc assumptions. This analysis, for which the input quantities are taken from kinetic, particle based simulations, allows the identification of all physical mechanisms involved and an accurate quantification of their contributions. The perfect agreement between the sum of these contributions and the simulation results verifies the completeness of the model. We study the relative importance of these mechanisms as a function of pressure, with high spatial and temporal resolution, in an electropositive argon discharge. In contrast to some widely accepted previous models we find that high space- and time-dependent ambipolar electric fields outside the sheaths play a key role for electron power absorption. This ambipolar field is time-dependent within the RF period and temporally asymmetric, i.e., the sheath expansion is not a ‘mirror image’ of the sheath collapse. We demonstrate that this time-dependence is mainly caused by a time modulation of the electron temperature resulting from the energy transfer to electrons by the ambipolar field itself during sheath expansion. We provide a theoretical proof that this ambipolar electron power absorption would vanish completely, if the electron temperature was constant in time. This mechanism of electron power absorption is based on a time modulated electron temperature, markedly different from the Hard Wall Model, of key importance for energy transfer to electrons on time average and, thus, essential for the generation of capacitively coupled plasmas.

A Numerical Solution Routine for Investigating Oxidation-Induced Strength Degradation Mechanisms in SiC/SiC Composites

NASA Technical Reports Server (NTRS)

Sullivan, Roy M.

2015-01-01

The stress rupture strength of silicon carbide fiber-reinforced silicon carbide (SiCSiC) composites with a boron nitride (BN) fiber coating decreases with time within the intermediate temperature range of 700-950 C. Various theories have been proposed to explain the cause of the time dependent stress rupture strength. Some previous authors have suggested that the observed composite strength behavior is due to the inherent time dependent strength of the fibers, which is caused by the slow growth of flaws within the fibers. Flaw growth is supposedly enabled by oxidation of free carbon at the grain boundaries. The objective of this paper is to investigate the relative significance of the various theories for the time-dependent strength of SiCSiC composites. This is achieved through the development of a numerically-based progressive failure analysis routine and through the application of the routine to simulate the composite stress rupture tests. The progressive failure routine is a time marching routine with an iterative loop between a probability of fiber survival equation and a force equilibrium equation within each time step. Failure of the composite is assumed to initiate near a matrix crack and the progression of fiber failures occurs by global load sharing. The probability of survival equation is derived from consideration of the strength of ceramic fibers with randomly occurring and slow growing flaws as well as the mechanical interaction between the fibers and matrix near a matrix crack. The force equilibrium equation follows from the global load sharing presumption. The results of progressive failure analyses of the composite tests suggest that the relationship between time and stress-rupture strength is attributed almost entirely to the slow flaw growth within the fibers. Although other mechanisms may be present, they appear to have only a minor influence on the observed time dependent behavior.

Characterization of the Exradin W1 scintillator for use in radiotherapy.

PubMed

Carrasco, P; Jornet, N; Jordi, O; Lizondo, M; Latorre-Musoll, A; Eudaldo, T; Ruiz, A; Ribas, M

2015-01-01

To evaluate the main characteristics of the Exradin W1 scintillator as a dosimeter and to estimate measurement uncertainties when used in radiotherapy. We studied the calibration procedure, energy and modality dependence, short-term repeatability, dose-response linearity, angular dependence, temperature dependence, time to reach thermal equilibrium, dose-rate dependence, water-equivalent depth of the effective measurement point, and long-term stability. An uncertainty budget was derived for relative and absolute dose measurements in photon and electron beams. Exradin W1 showed a temperature dependence of -0.225% °C(-1). The loss of sensitivity with accumulated dose decreased with use. The sensitivity of Exradin W1 was energy independent for high-energy photon and electron beams. All remaining dependencies of Exradin W1 were around or below 0.5%, leading to an uncertainty budget of about 1%. When a dual channel electrometer with automatic trigger was not used, timing effects became significant, increasing uncertainties by one order of magnitude. The Exradin W1 response is energy independent for high energy x-rays and electron beams, and only one calibration coefficient is needed. A temperature correction factor should be applied to keep uncertainties around 2% for absolute dose measurements and around 1% for relative measurements in high-energy photon and electron beams. The Exradin W1 scintillator is an excellent alternative to detectors such as diodes for relative dose measurements.

Dependence of Plastic TATB Shock-Wave Sensitivity on Temperature, Density and Technology Factors

NASA Astrophysics Data System (ADS)

Vlasov, Yu. A.; Kosolapov, V. B.; Fomicheva, L. V.; Khabarov, I. P.

1999-06-01

Mixed TATB-based HE is the most perspective because of the manufacture and exploitation safety of its items. At the same time the safety of these explosive, at high temperatures, which take place at emergencies, causes the certain anxiety. Plastic TATB shock-wave sensitivity (SWS) researches has shown that temperature as one of the important factors of external influence is not always the determining reason of SWS change. It is known that density influence on SWS significantly. At the same time density depends on temperature and technology of details manufacturing. In this connection in this work the temperature dependence of plastic TATB SWS was studied in view of convertible and irreversible changes of density (p) under heating at -50[C up to 90[C . It is shown that during these influences the dependence of threshold pressure of initiation (P) from temperature is explained, first of all, by change of HE density, caused by its thermal expansion (compression), and also by irreversible changes of p and HE structure, arising at heating. It is found also that the share of irreversible change of density depends on technology of HE details manufacturing and is explained by relaxation of residual pressure in them. The mentioned relaxation is finished after the first cycles of thermal influence. The value of density change, caused by this factor, depends on temperature and duration of heating.

The effects of alpha2-adrenoceptor agents on anti-hyperalgesic effects of carbamazepine and oxcarbazepine in a rat model of inflammatory pain.

PubMed

Vucković, Sonja M; Tomić, Maja A; Stepanović-Petrović, Radica M; Ugresić, Nenad; Prostran, Milica S; Bosković, Bogdan

2006-11-01

In this study, the effects of yohimbine (alpha2-adrenoceptor antagonist) and clonidine (alpha2-adrenoceptor agonist) on anti-hyperalgesia induced by carbamazepine and oxcarbazepine in a rat model of inflammatory pain were investigated. Carbamazepine (10-40 mg/kg; i.p.) and oxcarbazepine (40-160 mg/kg; i.p.) caused a significant dose-dependent reduction of the paw inflammatory hyperalgesia induced by concanavalin A (Con A, intraplantarly) in a paw pressure test in rats. Yohimbine (1-3 mg/kg; i.p.) significantly depressed the anti-hyperalgesic effects of carbamazepine and oxcarbazepine, in a dose- and time-dependent manner. Both drug mixtures (carbamazepine-clonidine and oxcarbazepine-clonidine) administered in fixed-dose fractions of the ED50 (1/2, 1/4 and 1/8) caused significant and dose-dependent reduction of the hyperalgesia induced by Con A. Isobolographic analysis revealed a significant synergistic (supra-additive) anti-hyperalgesic effect of both combinations tested. These results indicate that anti-hyperalgesic effects of carbamazepine and oxcarbazepine are, at least partially, mediated by activation of adrenergic alpha2-receptors. In addition, synergistic interaction for anti-hyperalgesia between carbamazepine and clonidine, as well as oxcarbazepine and clonidine in a model of inflammatory hyperalgesia, was demonstrated.

Impact of Tortuosity on Charge-Carrier Transport in Organic Bulk Heterojunction Blends

NASA Astrophysics Data System (ADS)

Heiber, Michael C.; Kister, Klaus; Baumann, Andreas; Dyakonov, Vladimir; Deibel, Carsten; Nguyen, Thuc-Quyen

2017-11-01

The impact of the tortuosity of the charge-transport pathways through a bulk heterojunction film on the charge-carrier mobility is theoretically investigated using model morphologies and kinetic Monte Carlo simulations. The tortuosity descriptor provides a quantitative metric to characterize the quality of the charge-transport pathways, and model morphologies with controlled domain size and tortuosity are created using an anisotropic domain growth procedure. The tortuosity is found to be dependent on the anisotropy of the domain structure and is highly tunable. Time-of-flight charge-transport simulations on morphologies with a range of tortuosity values reveal that tortuosity can significantly reduce the magnitude of the mobility and the electric-field dependence relative to a neat material. These reductions are found to be further controlled by the energetic disorder and temperature. Most significantly, the sensitivity of the electric-field dependence to the tortuosity can explain the different experimental relationships previously reported, and exploiting this sensitivity could lead to simpler methods for characterizing and optimizing charge transport in organic solar cells.

Efficacy of Naltrexone for the Treatment of Alcohol Dependence in Latino Populations.

PubMed

López, Cristina M; Barr, Simone C; Reid-Quiñones, Kathryn; de Arellano, Michael A

2017-05-01

Naltrexone has been identified as a promising psychopharmacological treatment for alcohol dependence. Previous studies have suggested that its efficacy may vary based on ethnic background. The current study examined the efficacy of naltrexone in the treatment of alcohol dependence in Latino adults, a previously unexplored population. This was a secondary analysis of the Combined Pharmacotherapies and Behavioral Interventions for Alcohol Dependence (COMBINE) Study. The overall COMBINE sample consisted of 1,383 adult participants who met Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria for alcohol dependence, including 155 Latinos, who are the focus of this report. Consistent with the main trial, primary drinking outcomes, including percentage of days abstinent (PDA) and time to first heavy drinking day (TTHD), were examined. In addition, we examined the effects of naltrexone on a clinically relevant secondary outcome measure, global clinical outcome of alcohol consumption and alcohol-related problems. As seen with the subsample of African Americans from the COMBINE Study, results of the present analysis indicated that there were no significant effects of naltrexone on PDA and TTHD despite these significant effects in the original study. However, contrary to findings in the African American subsample, for Latino participants naltrexone was a significant predictor of a good global clinical outcome (i.e., abstinence or moderate drinking without problems). Naltrexone was not significantly associated with improvements in the primary drinking outcomes of PDA or TTHD at the end of treatment or at follow-up. However, Latinos appeared to benefit from naltrexone as demonstrated by improved ratings of global clinical outcome. These results indicate mixed findings for the efficacy of naltrexone among Latinos in the COMBINE Study.

Frequency-dependent acceleration of relaxation in mammalian heart: a property not relying on phospholamban and SERCA2a phosphorylation

PubMed Central

Valverde, Carlos A; Mundiña-Weilenmann, Cecilia; Said, Matilde; Ferrero, Paola; Vittone, Leticia; Salas, Margarita; Palomeque, Julieta; Petroff, Martín Vila; Mattiazzi, Alicia

2005-01-01

An increase in stimulation frequency causes an acceleration of myocardial relaxation (FDAR). Several mechanisms have been postulated to explain this effect, among which is the Ca2+–calmodulin-dependent protein kinase (CaMKII)-dependent phosphorylation of the Thr17 site of phospholamban (PLN). To gain further insights into the mechanisms of FDAR, we studied the FDAR and the phosphorylation of PLN residues in perfused rat hearts, cat papillary muscles and isolated cat myocytes. This allowed us to sweep over a wide range of frequencies, in species with either positive or negative force–frequency relationships, as well as to explore the FDAR under isometric (or isovolumic) and isotonic conditions. Results were compared with those produced by isoprenaline, an intervention known to accelerate relaxation (IDAR) via PLN phosphorylation. While IDAR occurs tightly associated with a significant increase in the phosphorylation of Ser16 and Thr17 of PLN, FDAR occurs without significant changes in the phosphorylation of PLN residues in the intact heart and cat papillary muscles. Moreover, in intact hearts, FDAR was not associated with any significant change in the CaMKII-dependent phosphorylation of sarcoplasmic/endoplasmic Ca2+ ATPase (SERCA2a), and was not affected by the presence of the CaMKII inhibitor, KN-93. In isolated myocytes, FDAR occurred associated with an increase in Thr17 phosphorylation. However, for a similar relaxant effect produced by isoprenaline, the phosphorylation of PLN (Ser16 and Thr17) was significantly higher in the presence of the β-agonist. Moreover, the time course of Thr17 phosphorylation was significantly delayed with respect to the onset of FDAR. In contrast, the time course of Ser16 phosphorylation, the first residue that becomes phosphorylated with isoprenaline, was temporally associated with IDAR. Furthermore, KN-93 significantly decreased the phosphorylation of Thr17 that was evoked by increasing the stimulation frequency, but failed to affect FDAR. Taken together, the results provide direct evidence indicating that CaMKII phosphorylation pathways are not involved in FDAR and that FDAR and IDAR do not share a common underlying mechanism. More likely, a CaMKII-independent mechanism could be involved, whereby increasing stimulation frequency would disrupt the SERCA2a–PLN interaction, leading to an increase in SR Ca2+ uptake and myocardial relaxation. PMID:15528241

Commonly used stimulants: Sleep problems, dependence and psychological distress.

PubMed

Ogeil, Rowan P; Phillips, James G

2015-08-01

Caffeine and nicotine are commonly used stimulants that enhance alertness and mood. Discontinuation of both stimulants is associated with withdrawal symptoms including sleep and mood disturbances, which may differ in males and females. The present study examines changes in sleep quality, daytime sleepiness and psychological distress associated with use and dependence on caffeine and nicotine. An online survey comprising validated tools to assess sleep quality, excessive daytime sleepiness and psychological distress was completed by 166 participants (74 males, 96 females) with a mean age of 28 years. Participants completed the study in their own time, and were not offered any inducements to participate. Sleep quality was poorer in those dependent upon caffeine or nicotine, and there were also significant interaction effects with gender whereby females reported poorer sleep despite males reporting higher use of both stimulants. Caffeine dependence was associated with poorer sleep quality, increased daytime dysfunction, and increased levels of night time disturbance, while nicotine dependence was associated with poorer sleep quality and increased use of sleep medication and sleep disturbances. There were strong links between poor sleep and diminished affect, with psychological distress found to co-occur in the context of disturbed sleep. Stimulants are widely used to promote vigilance and mood; however, dependence on commonly used drugs including caffeine and nicotine is associated with decrements in sleep quality and increased psychological distress, which may be compounded in female dependent users. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Effects of BDNF receptor antagonist on the severity of physical and psychological dependence, morphine-induced locomotor sensitization and the ventral tegmental area-nucleus accumbens BDNF levels in morphine- dependent and withdrawn rats.

PubMed

Khalil-Khalili, Masoumeh; Rashidy-Pour, Ali; Bandegi, Ahmad Reza; Yousefi, Behpoor; Jorjani, Hassan; Miladi-Gorji, Hossein

2018-03-06

This study examined the effects of systemic administration of the TrkB receptor antagonist (ANA-12) on the severity of physical and psychological dependence and morphine-induced locomotor sensitization, the ventral tegmental area (VTA)-nucleus accumbens (NAc) BDNF levels in morphine-dependent and withdrawn rats. Rats were injected with bi-daily doses (10 mg/kg, at 12 h intervals) of morphine for 10 days. Then, rats were tested for naloxone-precipitated morphine withdrawal signs, the anxiety (the elevated plus maze-EPM) after the last morphine injection and injection of ANA12 (ip). Also, morphine-induced locomotor sensitization was evaluated after morphine challenge followed by an injection of ANA-12 in morphine-withdrawn rats. The VTA-NAc BDNF levels were assessed in morphine-dependent and withdrawn rats. The overall Gellert-Holtzman score was significantly higher in morphine-dependent rats receiving ANA-12 than in those receiving saline. Also, the percentage of time spent in the open arms in control and morphine-dependent rats receiving ANA-12 were higher compared to the Cont/Sal and D/Sal rats, respectively. There was no significant difference in the locomotor activity and the VTA-NAc BDNF levels between D/Sal/morphine and D/ANA-12/morphine groups after morphine withdrawal. We conclude that the systemic administration of ANA-12 exacerbates the severity of physical dependence on morphine and partially attenuates the anxiety-like behavior in morphine-dependent rats. However, ANA-12 did not affect morphine-induced locomotor sensitization and the VTA-NAc BDNF levels in morphine-dependent and withdrawn rats. Copyright © 2017 Elsevier B.V. All rights reserved.

Time-dependent strains and stresses in a pumpkin balloon

NASA Technical Reports Server (NTRS)

Gerngross, T.; Xu, Y.; Pellegrino, S.

2006-01-01

This paper presents a study of pumpkin-shaped superpressure balloons, consisting of gores made from a thin polymeric film attached to high stiffness, meridional tendons. This type of design is being used for the NASA ULDB balloons. The gore film shows considerable time-dependent stress relaxation, whereas the behaviour of the tendons is essentially time-independent. Upon inflation and pressurization, the "instantaneous", i.e. linear-elastic strain and stress distribution in the film show significantly higher values in the meridional direction. However, over time, and due to the biaxial visco-elastic stress relaxation of the the material, the hoop strains increase and the meridional stresses decrease, whereas the remaining strain and stress components remain substantially unchanged. These results are important for a correct assessment of the structural integrity of a pumpkin balloon in a long-duration mission, both in terms of the material performance and the overall stability of the shape of the balloon. An experimental investigation of the time dependence of the biaxial strain distribution in the film of a 4 m diameter, 48 gore pumpkin balloon is presented. The inflated shape of selected gores has been measured using photogrammetry and the time variation in strain components at some particular points of these gores has been measured under constant pressure and temperature. The results show good correlation with a numerical study, using the ABAQUS finite-element package, that includes a widely used model of the visco-elastic response of the gore material:

Tendon Contraction After Cyclic Elongation Is an Age-Dependent Phenomenon: In Vitro and In Vivo Comparisons.

PubMed

Lavagnino, Michael; Bedi, Asheesh; Walsh, Christopher P; Sibilsky Enselman, Elizabeth R; Sheibani-Rad, Shahin; Arnoczky, Steven P

2014-06-01

Tendons are viscoelastic tissues that deform (elongate) in response to cyclic loading. However, the ability of a tendon to recover this elongation is unknown. Tendon length significantly increases after in vivo or in vitro cyclic loading, and the ability to return to its original length through a cell-mediated contraction mechanism is an age-dependent phenomenon. Controlled laboratory study. In vitro, rat tail tendon fascicles (RTTfs) from Sprague-Dawley rats of 3 age groups (1, 3, and 12 months) underwent 2% cyclic strain at 0.17 Hz for 2 hours, and the percentages of elongation were determined. After loading, the RTTfs were suspended for 3 days under tissue culture conditions and photographed daily to determine the amount of length contraction. In vivo, healthy male participants (n = 29; age, 19-49 years) had lateral, single-legged weightbearing radiographs taken of the knee at 60° of flexion immediately before, immediately after, and 24 hours after completing eccentric quadriceps loading exercises on the dominant leg to fatigue. Measurements of patellar tendon length were taken from the radiographs, and the percentages of tendon elongation and subsequent contraction were calculated. In vitro, cyclic loading increased the length of all RTTfs, with specimens from younger (1 and 3 months) rats demonstrating significantly greater elongation than those from older (12 months) rats (P = .009). The RTTfs contracted to their original length significantly faster (P < .001) and in an age-dependent fashion, with younger animals contracting faster. In vivo, repetitive eccentric loading exercises significantly increased patellar tendon length (P < .001). Patellar tendon length decreased 24 hours after exercises (P < .001) but did not recover completely (P < .001). There was a weak but significant (R (2) = 0.203, P = .014) linear correlation between the amount of tendon contraction and age, with younger participants (<30 years) demonstrating significantly more contraction (P = .014) at 24 hours than older participants (>30 years). Cyclic tendon loading results in a significant increase in tendon elongation under both in vitro and in vivo conditions. Tendons in both conditions demonstrated an incomplete return to their original length after 24 hours, and the extent of this return was age dependent. The age- and time-dependent contraction of tendons, elongated after repetitive loading, could result in transient alterations in the mechanobiological environment of tendon cells. This, in turn, could induce the onset of catabolic changes associated with the pathogenesis of tendinopathy. These results suggest the importance of allowing time for contraction between bouts of repetitive exercise and may explain why age is a predisposing factor in tendinopathy. © 2014 The Author(s).

Effects of Copper on Hemocyte Apoptosis, ROS Production, and Gene Expression in White Shrimp Litopenaeus vannamei.

PubMed

Guo, Hui; Li, Kexu; Wang, Wei; Wang, Chenggui; Shen, Yuchun

2017-10-01

Copper, a common chemical contaminant in aquatic environment, is known to be toxic to aquatic life at high concentrations. In the present study, we evaluated the apoptotic cell ratio and ROS production in hemocytes of the white shrimp Litopenaeus vannamei exposed to 1 or 5 mg L -1 Cu for 0, 3, 6, 12, 24, and 48 h. The expression changes of antioxidant biomarker genes, i.e., copper-zinc superoxide dismutase (Cu-Zn SOD) and catalase (CAT), apoptosis-related genes, i.e., caspase-3 and inhibitor of apoptosis protein (IAP), and a specific biomarker gene of heavy metal pollution, i.e., metallothionein (MT), were also determined in hemocytes. Significant increases in ROS production were observed in both treatment groups at each time points. The apoptotic cell ratios were significantly increased at 6-48 h among shrimp exposed to 1 mg L -1 Cu and at each time points in 5 mg L -1 Cu group. These results indicated that Cu would induce oxidative stress and apoptosis in the hemocyte of L. vannamei. Quantitative real-time PCR analysis revealed that the relative expression levels of Cu-Zn SOD, CAT, caspase-3, IAP, and MT were upregulated in a dose-dependent and time-dependent manner, suggesting the involvement of these genes in stress response against Cu exposure.

Time of Day Does Not Modulate Improvements in Motor Performance following a Repetitive Ballistic Motor Training Task

PubMed Central

Sale, Martin V.; Ridding, Michael C.; Nordstrom, Michael A.

2013-01-01

Repetitive performance of a task can result in learning. The neural mechanisms underpinning such use-dependent plasticity are influenced by several neuromodulators. Variations in neuromodulator levels may contribute to the variability in performance outcomes following training. Circulating levels of the neuromodulator cortisol change throughout the day. High cortisol levels inhibit neuroplasticity induced with a transcranial magnetic stimulation (TMS) paradigm that has similarities to use-dependent plasticity. The present study investigated whether performance changes following a motor training task are modulated by time of day and/or changes in endogenous cortisol levels. Motor training involving 30 minutes of repeated maximum left thumb abduction was undertaken by twenty-two participants twice, once in the morning (8 AM) and once in the evening (8 PM) on separate occasions. Saliva was assayed for cortisol concentration. Motor performance, quantified by measuring maximum left thumb abduction acceleration, significantly increased by 28% following training. Neuroplastic changes in corticomotor excitability of abductor pollicis brevis, quantified with TMS, increased significantly by 23% following training. Training-related motor performance improvements and neuroplasticity were unaffected by time of day and salivary cortisol concentration. Although similar neural elements and processes contribute to motor learning, training-induced neuroplasticity, and TMS-induced neuroplasticity, our findings suggest that the influence of time of day and cortisol differs for these three interventions. PMID:23577271

Scattering of accelerated wave packets

NASA Astrophysics Data System (ADS)

Longhi, S.; Horsley, S. A. R.; Della Valle, G.

2018-03-01

Wave-packet scattering from a stationary potential is significantly modified when the wave packet is subject to an external time-dependent force during the interaction. In the semiclassical limit, wave-packet motion is simply described by Newtonian equations, and the external force can, for example, cancel the potential force, making a potential barrier transparent. Here we consider wave-packet scattering from reflectionless potentials, where in general the potential becomes reflective when probed by an accelerated wave packet. In the particular case of the recently introduced class of complex Kramers-Kronig potentials we show that a broad class of time-dependent forces can be applied without inducing any scattering, while there is a breakdown of the reflectionless property when there is a broadband distribution of initial particle momentum, involving both positive and negative components.

A time dependent anatomically detailed model of cardiac conduction

NASA Technical Reports Server (NTRS)

Saxberg, B. E.; Grumbach, M. P.; Cohen, R. J.

1985-01-01

In order to understand the determinants of transitions in cardiac electrical activity from normal patterns to dysrhythmias such as ventricular fibrillation, we are constructing an anatomically and physiologically detailed finite element simulation of myocardial electrical propagation. A healthy human heart embedded in paraffin was sectioned to provide a detailed anatomical substrate for model calculations. The simulation of propagation includes anisotropy in conduction velocity due to fiber orientation as well as gradients in conduction velocities, absolute and relative refractory periods, action potential duration and electrotonic influence of nearest neighbors. The model also includes changes in the behaviour of myocardial tissue as a function of the past local activity. With this model, we can examine the significance of fiber orientation and time dependence of local propagation parameters on dysrhythmogenesis.

Patterns of nicotine dependence in four Eastern European countries.

PubMed

Kaleta, Dorota; Polańska, Kinga; Korytkowski, Przemysław; Usidame, Bukola; Bąk-Romaniszyn, Leokadia

2015-11-28

Evidence of patterns of nicotine dependence, although crucial for developing and implementing effective tobacco control strategies, is limited in the Eastern European countries. The purpose of this study was to evaluate the correlates of high nicotine dependence among adults in Poland, Romania, the Russian Federation and Ukraine. The data used in the current analysis is available from the Global Adult Tobacco Survey (2009-2011). Nicotine dependence was assessed using the Heaviness of Smoking Index (HSI), which covers two measures: reported cigarettes smoked per day and time to the first cigarette upon waking. Based on a six-point scale of HSI, nicotine dependence was categorized into low to moderate (score 0-3), and high dependence (score 4-6). Out of 31,936 completed interviews, we used data from 8229 daily smokers. The study results indicate that more than 25 % of daily smokers were highly dependent on nicotine. Higher odds of high nicotine dependence were identified for males (OR = 1.5 in Poland and Romania, OR = 2.7 in Russia; p ≤ 0.001), people between 50-59 years of age (the highest odds in Romania; OR = 4.8; p ≤ 0.001) and those who had started smoking at a young age (the highest odds in Romania, OR = 5.0; p ≤ 0.001). Having fewer restrictions on smoking at home was significantly associated with a high level of nicotine dependence (the highest odds in Romania, OR = 3.0; p ≤ 0.001). A high proportion of the participants had no interest in quitting smoking, with a statistically significantly higher percentage observed among smokers highly dependent on nicotine compared to the less addicted (p ≤ 0.01). Smokers highly dependent on nicotine constitute a quarter of the Romanian group of daily smokers and even more in the remaining three analyzed countries. Similar patterns of nicotine dependence were observed in all of the investigated countries showing that male gender, younger age at the smoking onset, and fewer restrictions on smoking at home were significantly associated with higher nicotine dependence. The study highlighted the fact that a high proportion of the participants had no interest in quitting smoking. These results underscore importance of policy measures as well as prevention and cessation interventions for smokers who are highly dependent on nicotine, which need to take into account the social gradient in smoking patterns.

Electronic and optical properties of pure and modified diamondoids studied by many-body perturbation theory and time-dependent density functional theory

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

Demján, Tamás; Institute for Solid State Physics and Optics, Wigner Research Center for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest; Vörös, Márton

2014-08-14

Diamondoids are small diamond nanoparticles (NPs) that are built up from diamond cages. Unlike usual semiconductor NPs, their atomic structure is exactly known, thus they are ideal test-beds for benchmarking quantum chemical calculations. Their usage in spintronics and bioimaging applications requires a detailed knowledge of their electronic structure and optical properties. In this paper, we apply density functional theory (DFT) based methods to understand the electronic and optical properties of a few selected pure and modified diamondoids for which accurate experimental data exist. In particular, we use many-body perturbation theory methods, in the G{sub 0}W{sub 0} and G{sub 0}W{sub 0}+BSEmore » approximations, and time-dependent DFT in the adiabatic local density approximation. We find large quasiparticle gap corrections that can exceed thrice the DFT gap. The electron-hole binding energy can be as large as 4 eV but it is considerably smaller than the GW corrections and thus G{sub 0}W{sub 0}+BSE optical gaps are about 50% larger than the Kohn-Sham (KS) DFT gaps. We find significant differences between KS time-dependent DFT and GW+BSE optical spectra on the selected diamondoids. The calculated G{sub 0}W{sub 0} quasiparticle levels agree well with the corresponding experimental vertical ionization energies. We show that nuclei dynamics in the ionization process can be significant and its contribution may reach about 0.5 eV in the adiabatic ionization energies.« less

Crustal uplift in the south central Alaska subduction zone: New analysis and interpretation of tide gauge observations

NASA Astrophysics Data System (ADS)

Cohen, Steven C.; Freymueller, Jeffrey T.

2001-06-01

We have examined tide gauge measurements of apparent sea level height in south central Alaska to determine the history of crustal uplift subsequent to the 1964 Prince William Sound earthquake. There are spatial and temporal variations in the uplift rate since the 1994 earthquake that depend on the location of the tide gauge relative to the coseismic rupture features. At Seward, on the eastern side of the Kenai Peninsula, we find slow uplift that is consistent with elastic strain accumulation at the locked North American-Pacific Plate boundary. Conversely, at Seldovia and Nikiski, on the western side of the Kenai Peninsula, we find persistent rapid uplift of ˜10 mm yr-1 that may be longterm transient response to the earthquake but that cannot be sustained over the entire several hundred year recurrence interval for a great earthquake. Farther to the southwest, at Kodiak, the rate of uplift is several millimeters per year but has slowed significantly over the past three and a half decades. To the east of the Kenai Peninsula we find subsidence at Cordova and an uncertain behavior at Valdez. At Cordova, and to a lesser extent Valdez, there is a mathematically significant time dependence, although the evidence for the time dependence is less compelling than at Kodiak. At Anchorage, there is little evidence of vertical motion since the earthquake. The along-strike spatial variability in the relaxation time of the rates of vertical motion since the 1964 earthquake may be related to variations in the updip coseismic slip during the megathrust event.

DOI Determination by Rise Time Discrimination in Single-Ended Readout for TOF PET Imaging

PubMed Central

Wiener, R.I.; Surti, S.; Karp, J.S.

2013-01-01

Clinical TOF PET systems achieve detection efficiency using thick crystals, typically of thickness 2–3cm. The resulting dispersion in interaction depths degrades spatial resolution for increasing radial positions due to parallax error. Furthermore, interaction depth dispersion results in time pickoff dispersion and thus in degraded timing resolution, and is therefore of added concern in TOF scanners. Using fast signal digitization, we characterize the timing performance, pulse shape and light output of LaBr3:Ce, CeBr3 and LYSO. Coincidence timing resolution is shown to degrade by ~50ps/cm for scintillator pixels of constant cross section and increasing length. By controlling irradiation depth in a scintillator pixel, we show that DOI-dependence of time pickoff is a significant factor in the loss of timing performance in thick detectors. Using the correlated DOI-dependence of time pickoff and charge collection, we apply a charge-based correction to the time pickoff, obtaining improved coincidence timing resolution of <200ps for a uniform 4×4×30mm3 LaBr3 pixel. In order to obtain both DOI identification and improved timing resolution, we design a two layer LaBr3[5%Ce]/LaBr3[30%Ce] detector of total size 4×4×30mm3, exploiting the dependence of scintillator rise time on [Ce] in LaBr3:Ce. Using signal rise time to determine interaction layer, excellent interaction layer discrimination is achieved, while maintaining coincidence timing resolution of <250ps and energy resolution <7% using a R4998 PMT. Excellent layer separation and timing performance is measured with several other commercially-available TOF photodetectors, demonstrating the practicality of this design. These results indicate the feasibility of rise time discrimination as a technique for measuring event DOI while maintaining sensitivity, timing and energy performance, in a well-known detector architecture. PMID:24403611

DOI Determination by Rise Time Discrimination in Single-Ended Readout for TOF PET Imaging.

PubMed

Wiener, R I; Surti, S; Karp, J S

2013-06-01

Clinical TOF PET systems achieve detection efficiency using thick crystals, typically of thickness 2-3cm. The resulting dispersion in interaction depths degrades spatial resolution for increasing radial positions due to parallax error. Furthermore, interaction depth dispersion results in time pickoff dispersion and thus in degraded timing resolution, and is therefore of added concern in TOF scanners. Using fast signal digitization, we characterize the timing performance, pulse shape and light output of LaBr 3 :Ce, CeBr 3 and LYSO. Coincidence timing resolution is shown to degrade by ~50ps/cm for scintillator pixels of constant cross section and increasing length. By controlling irradiation depth in a scintillator pixel, we show that DOI-dependence of time pickoff is a significant factor in the loss of timing performance in thick detectors. Using the correlated DOI-dependence of time pickoff and charge collection, we apply a charge-based correction to the time pickoff, obtaining improved coincidence timing resolution of <200ps for a uniform 4×4×30mm 3 LaBr 3 pixel. In order to obtain both DOI identification and improved timing resolution, we design a two layer LaBr 3 [5%Ce]/LaBr 3 [30%Ce] detector of total size 4×4×30mm 3 , exploiting the dependence of scintillator rise time on [Ce] in LaBr 3 :Ce. Using signal rise time to determine interaction layer, excellent interaction layer discrimination is achieved, while maintaining coincidence timing resolution of <250ps and energy resolution <7% using a R4998 PMT. Excellent layer separation and timing performance is measured with several other commercially-available TOF photodetectors, demonstrating the practicality of this design. These results indicate the feasibility of rise time discrimination as a technique for measuring event DOI while maintaining sensitivity, timing and energy performance, in a well-known detector architecture.

Determination of Age-Dependent Reference Ranges for Coagulation Tests Performed Using Destiny Plus.

PubMed

Arslan, Fatma Demet; Serdar, Muhittin; Merve Ari, Elif; Onur Oztan, Mustafa; Hikmet Kozcu, Sureyya; Tarhan, Huseyin; Cakmak, Ozgur; Zeytinli, Merve; Yasar Ellidag, Hamit

2016-06-01

In order to apply the right treatment for hemostatic disorders in pediatric patients, laboratory data should be interpreted with age-appropriate reference ranges. The purpose of this study was to determining age-dependent reference range values for prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen tests, and D-dimer tests. A total of 320 volunteers were included in the study with the following ages: 1 month - 1 year (n = 52), 2 - 5 years (n = 50), 6 - 10 years (n = 48), 11 - 17 years (n = 38), and 18 - 65 years (n = 132). Each volunteer completed a survey to exclude hemostatic system disorder. Using a nonparametric method, the lower and upper limits, including 95% distribution and 90% confidence intervals, were calculated. No statistically significant differences were found between PT and aPTT values in the groups consisting of children. Thus, the reference ranges were separated into child and adult age groups. PT and aPTT values were significantly higher in the children than in the adults. Fibrinogen values in the 6 - 10 age group and the adult age group were significantly higher than in the other groups. D-dimer levels were significantly lower in those aged 2 - 17; thus, a separate reference range was established. These results support other findings related to developmental hemostasis, confirming that adult and pediatric age groups should be evaluated using different reference ranges.

Bayesian Analysis of Non-Gaussian Long-Range Dependent Processes

NASA Astrophysics Data System (ADS)

Graves, Timothy; Watkins, Nicholas; Franzke, Christian; Gramacy, Robert

2013-04-01

Recent studies [e.g. the Antarctic study of Franzke, J. Climate, 2010] have strongly suggested that surface temperatures exhibit long-range dependence (LRD). The presence of LRD would hamper the identification of deterministic trends and the quantification of their significance. It is well established that LRD processes exhibit stochastic trends over rather long periods of time. Thus, accurate methods for discriminating between physical processes that possess long memory and those that do not are an important adjunct to climate modeling. As we briefly review, the LRD idea originated at the same time as H-selfsimilarity, so it is often not realised that a model does not have to be H-self similar to show LRD [e.g. Watkins, GRL Frontiers, 2013]. We have used Markov Chain Monte Carlo algorithms to perform a Bayesian analysis of Auto-Regressive Fractionally-Integrated Moving-Average ARFIMA(p,d,q) processes, which are capable of modeling LRD. Our principal aim is to obtain inference about the long memory parameter, d, with secondary interest in the scale and location parameters. We have developed a reversible-jump method enabling us to integrate over different model forms for the short memory component. We initially assume Gaussianity, and have tested the method on both synthetic and physical time series. Many physical processes, for example the Faraday Antarctic time series, are significantly non-Gaussian. We have therefore extended this work by weakening the Gaussianity assumption, assuming an alpha-stable distribution for the innovations, and performing joint inference on d and alpha. Such a modified FARIMA(p,d,q) process is a flexible, initial model for non-Gaussian processes with long memory. We will present a study of the dependence of the posterior variance of the memory parameter d on the length of the time series considered. This will be compared with equivalent error diagnostics for other measures of d.

Time dependent heat transfer rates in high Reynolds number hypersonic flowfields

NASA Technical Reports Server (NTRS)

Flanagan, Michael J.

1992-01-01

Time dependent heat transfer rates have been calculated from time dependent temperature measurements in the vicinity of shock-wave boundary-layer interactions due to conical compression ramps on an axisymmetric body. The basic model is a cylindrical body with a 10 degree conical nose. Four conical ramps, 20, 25, 30, and 35 degrees serve as shock wave generators. Flowfield surveys have been made in the vicinity of the conical ramp vertex, the separation point, and the reattachment point. A significant effort was made to characterize the natural frequencies and relative powers of the resulting fluctuations in heat transfer rates. This research effort, sponsored jointly by NASA and the Air Force, was conducted in the Air Force Flight Dynamics Directorate High Reynolds Facility. The nominal freestream Mach number was 6, and the freestream Reynolds numbers ranged from 2.2 million/ft to 30.0 million/ft. Experimental results quantify temperature response and the resulting heat transfer rates as a function of ramp angle and Reynolds number. The temperature response within the flowfield appears to be steady-state for all compression ramp angles and all Reynolds numbers, and hence, the heat transfer rates appear to be steady-state.

Time dependent heat transfer rates in high Reynolds number hypersonic flowfields

NASA Astrophysics Data System (ADS)

Flanagan, Michael J.

1992-09-01

Time dependent heat transfer rates have been calculated from time dependent temperature measurements in the vicinity of shock-wave boundary-layer interactions due to conical compression ramps on an axisymmetric body. The basic model is a cylindrical body with a 10 degree conical nose. Four conical ramps, 20, 25, 30, and 35 degrees serve as shock wave generators. Flowfield surveys have been made in the vicinity of the conical ramp vertex, the separation point, and the reattachment point. A significant effort was made to characterize the natural frequencies and relative powers of the resulting fluctuations in heat transfer rates. This research effort, sponsored jointly by NASA and the Air Force, was conducted in the Air Force Flight Dynamics Directorate High Reynolds Facility. The nominal freestream Mach number was 6, and the freestream Reynolds numbers ranged from 2.2 million/ft to 30.0 million/ft. Experimental results quantify temperature response and the resulting heat transfer rates as a function of ramp angle and Reynolds number. The temperature response within the flowfield appears to be steady-state for all compression ramp angles and all Reynolds numbers, and hence, the heat transfer rates appear to be steady-state.

Different storage conditions influence biocompatibility and physicochemical properties of iron oxide nanoparticles.

PubMed

Zaloga, Jan; Janko, Christina; Agarwal, Rohit; Nowak, Johannes; Müller, Robert; Boccaccini, Aldo R; Lee, Geoffrey; Odenbach, Stefan; Lyer, Stefan; Alexiou, Christoph

2015-04-24

Superparamagnetic iron oxide nanoparticles (SPIONs) have attracted increasing attention in many biomedical fields. In magnetic drug targeting SPIONs are injected into a tumour supplying artery and accumulated inside the tumour with a magnet. The effectiveness of this therapy is thus dependent on magnetic properties, stability and biocompatibility of the particles. A good knowledge of the effect of storage conditions on those parameters is of utmost importance for the translation of the therapy concept into the clinic and for reproducibility in preclinical studies. Here, core shell SPIONs with a hybrid coating consisting of lauric acid and albumin were stored at different temperatures from 4 to 45 °C over twelve weeks and periodically tested for their physicochemical properties over time. Surprisingly, even at the highest storage temperature we did not observe denaturation of the protein or colloidal instability. However, the saturation magnetisation decreased by maximally 28.8% with clear correlation to time and storage temperature. Furthermore, the biocompatibility was clearly affected, as cellular uptake of the SPIONs into human T-lymphoma cells was crucially dependent on the storage conditions. Taken together, the results show that the particle properties undergo significant changes over time depending on the way they are stored.

Variability of the hemodynamic response as a function of age and frequency of epileptic discharge in children with epilepsy.

PubMed

Jacobs, Julia; Hawco, Colin; Kobayashi, Eliane; Boor, Rainer; LeVan, Pierre; Stephani, Ulrich; Siniatchkin, Michael; Gotman, Jean

2008-04-01

EEG-fMRI is a non-invasive tool to investigate epileptogenic networks in patients with epilepsy. Different patterns of BOLD responses have been observed in children as compared to adults. A high intra- and intersubject variability of the hemodynamic response function (HRF) to epileptic discharges has been observed in adults. The actual HRF to epileptic discharges in children and its dependence on age are unknown. We analyzed 64 EEG-fMRI event types in 37 children (3 months to 18 years), 92% showing a significant BOLD response. HRFs were calculated for each BOLD cluster using a Fourier basis set. After excluding HRFs with a low signal-to-noise ratio, 126 positive and 98 negative HRFs were analyzed. We evaluated age-dependent changes as well as the effect of increasing numbers of spikes. Peak time, amplitude and signal-to-noise ratio of the HRF and the t-statistic score of the cluster were used as dependent variables. We observed significantly longer peak times of the HRF in the youngest children (0 to 2 years), suggesting that the use of multiple HRFs might be important in this group. A different coupling between neuronal activity and metabolism or blood flow in young children may cause this phenomenon. Even if the t-value increased with frequent spikes, the amplitude of the HRF decreased significantly with spike frequency. This reflects a violation of the assumptions of the General Linear Model and therefore the use of alternative analysis techniques may be more appropriate with high spiking rates, a common situation in children.

Variability of the hemodynamic response as a function of age and frequency of epileptic discharge in children with epilepsy

PubMed Central

Jacobs, Julia; Hawco, Colin; Kobayashi, Eliane; Boor, Rainer; LeVan, Pierre; Stephani, Ulrich; Siniatchkin, Michael; Gotman, Jean

2013-01-01

EEG-fMRI is a non-invasive tool to investigate epileptogenic networks in patients with epilepsy. Different patterns of BOLD responses have been observed in children as compared to adults. A high intra- and intersubject variability of the hemodynamic response function (HRF) to epileptic discharges has been observed in adults. The actual HRF to epileptic discharges in children and its dependence on age are unknown. We analyzed 64 EEG-fMRI event types in 37 children (3 months to 18 years), 92% showing a significant BOLD response. HRFs were calculated for each BOLD cluster using a Fourier basis set. After excluding HRFs with a low signal-to-noise ratio, 126 positive and 98 negative HRFs were analyzed. We evaluated age-dependent changes as well as the effect of increasing numbers of spikes. Peak time, amplitude and signal-to-noise ratio of the HRF and the t-statistic score of the cluster were used as dependent variables. We observed significantly longer peak times of the HRF in the youngest children (0 to 2 years), suggesting that the use of multiple HRFs might be important in this group. A different coupling between neuronal activity and metabolism or blood flow in young children may cause this phenomenon. Even if the t-value increased with frequent spikes, the amplitude of the HRF decreased significantly with spike frequency. This reflects a violation of the assumptions of the General Linear Model and therefore the use of alternative analysis techniques may be more appropriate with high spiking rates, a common situation in children. PMID:18221891

Differential Changes in Expression of Stress- and Metabolic-Related Neuropeptides in the Rat Hypothalamus during Morphine Dependence and Withdrawal

PubMed Central

Núnez, Cristina; Zelei, Edina; Polyák, Ágnes; Milanés, M. Victoria

2013-01-01

Chronic morphine treatment and naloxone precipitated morphine withdrawal activates stress-related brain circuit and results in significant changes in food intake, body weight gain and energy metabolism. The present study aimed to reveal hypothalamic mechanisms underlying these effects. Adult male rats were made dependent on morphine by subcutaneous implantation of constant release drug pellets. Pair feeding revealed significantly smaller weight loss of morphine treated rats compared to placebo implanted animals whose food consumption was limited to that eaten by morphine implanted pairs. These results suggest reduced energy expenditure of morphine-treated animals. Chronic morphine exposure or pair feeding did not significantly affect hypothalamic expression of selected stress- and metabolic related neuropeptides - corticotropin-releasing hormone (CRH), urocortin 2 (UCN2) and proopiomelanocortin (POMC) compared to placebo implanted and pair fed animals. Naloxone precipitated morphine withdrawal resulted in a dramatic weight loss starting as early as 15–30 min after naloxone injection and increased adrenocorticotrophic hormone, prolactin and corticosterone plasma levels in morphine dependent rats. Using real-time quantitative PCR to monitor the time course of relative expression of neuropeptide mRNAs in the hypothalamus we found elevated CRH and UCN2 mRNA and dramatically reduced POMC expression. Neuropeptide Y (NPY) and arginine vasopressin (AVP) mRNA levels were transiently increased during opiate withdrawal. These data highlight that morphine withdrawal differentially affects expression of stress- and metabolic-related neuropeptides in the rat hypothalamus, while relative mRNA levels of these neuropeptides remain unchanged either in rats chronically treated with morphine or in their pair-fed controls. PMID:23805290

Irradiation-Dependent Effects on Tumor Perfusion and Endogenous and Exogenous Hypoxia Markers in an A549 Xenograft Model

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

Fokas, Emmanouil, E-mail: emmanouil.fokas@yahoo.d; Haenze, Joerg; Kamlah, Florentine

2010-08-01

Purpose: Hypoxia is a major determinant of tumor radiosensitivity, and microenvironmental changes in response to ionizing radiation (IR) are often heterogenous. We analyzed IR-dependent changes in hypoxia and perfusion in A549 human lung adenocarcinoma xenografts. Materials and Methods: Immunohistological analysis of two exogenously added chemical hypoxic markers, pimonidazole and CCI-103F, and of the endogenous marker Glut-1 was performed time dependently after IR. Tumor vessels and apoptosis were analyzed using CD31 and caspase-3 antibodies. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and fluorescent beads (Hoechst 33342) were used to monitor vascular perfusion. Results: CCI-103F signals measuring the fraction of hypoxic areas aftermore » IR were significantly decreased by approximately 50% when compared with pimonidazole signals, representing the fraction of hypoxic areas from the same tumors before IR. Interestingly, Glut-1 signals were significantly decreased at early time point (6.5 h) after IR returning to the initial levels at 30.5 h. Vascular density showed no difference between irradiated and control groups, whereas apoptosis was significantly induced at 10.5 h post-IR. DCE-MRI indicated increased perfusion 1 h post-IR. Conclusions: The discrepancy between the hypoxic fractions of CCI-103F and Glut-1 forces us to consider the possibility that both markers reflect different metabolic alterations of tumor microenvironment. The reliability of endogenous markers such as Glut-1 to measure reoxygenation in irradiated tumors needs further consideration. Monitoring tumor microvascular response to IR by DCE-MRI and measuring tumor volume alterations should be encouraged.« less

A prediction model for colon cancer surveillance data.

PubMed

Good, Norm M; Suresh, Krithika; Young, Graeme P; Lockett, Trevor J; Macrae, Finlay A; Taylor, Jeremy M G

2015-08-15

Dynamic prediction models make use of patient-specific longitudinal data to update individualized survival probability predictions based on current and past information. Colonoscopy (COL) and fecal occult blood test (FOBT) results were collected from two Australian surveillance studies on individuals characterized as high-risk based on a personal or family history of colorectal cancer. Motivated by a Poisson process, this paper proposes a generalized nonlinear model with a complementary log-log link as a dynamic prediction tool that produces individualized probabilities for the risk of developing advanced adenoma or colorectal cancer (AAC). This model allows predicted risk to depend on a patient's baseline characteristics and time-dependent covariates. Information on the dates and results of COLs and FOBTs were incorporated using time-dependent covariates that contributed to patient risk of AAC for a specified period following the test result. These covariates serve to update a person's risk as additional COL, and FOBT test information becomes available. Model selection was conducted systematically through the comparison of Akaike information criterion. Goodness-of-fit was assessed with the use of calibration plots to compare the predicted probability of event occurrence with the proportion of events observed. Abnormal COL results were found to significantly increase risk of AAC for 1 year following the test. Positive FOBTs were found to significantly increase the risk of AAC for 3 months following the result. The covariates that incorporated the updated test results were of greater significance and had a larger effect on risk than the baseline variables. Copyright © 2015 John Wiley & Sons, Ltd.

Can a simple lumped parameter model simulate complex transit time distributions? Benchmarking experiments in a virtual watershed.

NASA Astrophysics Data System (ADS)

Wilusz, D. C.; Maxwell, R. M.; Buda, A. R.; Ball, W. P.; Harman, C. J.

2016-12-01

The catchment transit-time distribution (TTD) is the time-varying, probabilistic distribution of water travel times through a watershed. The TTD is increasingly recognized as a useful descriptor of a catchment's flow and transport processes. However, TTDs are temporally complex and cannot be observed directly at watershed scale. Estimates of TTDs depend on available environmental tracers (such as stable water isotopes) and an assumed model whose parameters can be inverted from tracer data. All tracers have limitations though, such as (typically) short periods of observation or non-conservative behavior. As a result, models that faithfully simulate tracer observations may nonetheless yield TTD estimates with significant errors at certain times and water ages, conditioned on the tracer data available and the model structure. Recent advances have shown that time-varying catchment TTDs can be parsimoniously modeled by the lumped parameter rank StorAge Selection (rSAS) model, in which an rSAS function relates the distribution of water ages in outflows to the composition of age-ranked water in storage. Like other TTD models, rSAS is calibrated and evaluated against environmental tracer data, and the relative influence of tracer-dependent and model-dependent error on its TTD estimates is poorly understood. The purpose of this study is to benchmark the ability of different rSAS formulations to simulate TTDs in a complex, synthetic watershed where the lumped model can be calibrated and directly compared to a virtually "true" TTD. This experimental design allows for isolation of model-dependent error from tracer-dependent error. The integrated hydrologic model ParFlow with SLIM-FAST particle tracking code is used to simulate the watershed and its true TTD. To add field intelligence, the ParFlow model is populated with over forty years of hydrometric and physiographic data from the WE-38 subwatershed of the USDA's Mahantango Creek experimental catchment in PA, USA. The results are intended to give practical insight into tradeoffs between rSAS model structure and skill, and define a new performance benchmark to which other transit time models can be compared.

Humidity-dependent bacterial cells functional morphometry investigations using atomic force microscope.

PubMed

Nikiyan, Hike; Vasilchenko, Alexey; Deryabin, Dmitry

2010-01-01

The effect of a relative humidity (RH) in a range of 93-65% on morphological and elastic properties of Bacillus cereus and Escherichia coli cells was evaluated using atomic force microscopy. It is shown that gradual dehumidification of bacteria environment has no significant effect on cell dimensional features and considerably decreases them only at 65% RH. The increasing of the bacteria cell wall roughness and elasticity occurs at the same time. Observed changes indicate that morphological properties of B. cereus are rather stable in wide range of relative humidity, whereas E. coli are more sensitive to drying, significantly increasing roughness and stiffness parameters at RH

Integrated care for comorbid alcohol dependence and anxiety and/or depressive disorder: study protocol for an assessor-blind, randomized controlled trial.

PubMed

Morley, Kirsten C; Baillie, Andrew; Sannibale, Claudia; Teesson, Maree; Haber, Paul S

2013-11-19

A major barrier to successful treatment in alcohol dependence is psychiatric comorbidity. During treatment, the time to relapse is shorter, the drop-out rate is increased, and long-term alcohol consumption is greater for those with comorbid major depression or anxiety disorder than those with an alcohol use disorder with no comorbid mental disorder. The treatment of alcohol dependence and psychological disorders is often the responsibility of different services, and this can hinder the treatment process. Accordingly, there is a need for an effective integrated treatment for alcohol dependence and comorbid anxiety and/or depression. We aim to assess the effectiveness of a specialized, integrated intervention for alcohol dependence with comorbid anxiety and/or mood disorder using a randomized design in an outpatient hospital setting. Following a three-week stabilization period (abstinence or significantly reduced consumption), participants will undergo complete formal assessment for anxiety and depression. Those patients with a diagnosis of an anxiety and/or depressive disorder will be randomized to either 1) integrated intervention (cognitive behavioral therapy) for alcohol, anxiety, and/or depression; or 2) usual counseling care for alcohol problems. Patients will then be followed up at weeks 12, 16, and 24. The primary outcome measure is alcohol consumption (total abstinence, time to lapse, and time to relapse). Secondary outcome measures include changes in alcohol dependence severity, depression, or anxiety symptoms and changes in clinician-rated severity of anxiety and depression. The study findings will have potential implications for clinical practice by evaluating the implementation of specialized integrated treatment for comorbid anxiety and/or depression in an alcohol outpatient service. ClinicalTrials.gov Identifier: NCT01941693.

Nicotine Dependence and Alcohol Problems from Adolescence to Young Adulthood.

PubMed

Dierker, Lisa; Selya, Arielle; Rose, Jennifer; Hedeker, Donald; Mermelstein, Robin

Despite the highly replicated relationship between symptoms associated with both alcohol and nicotine, little is known about this association across time and exposure to both drinking and smoking. In the present study, we evaluate if problems associated with alcohol use are related to emerging nicotine dependence symptoms and whether this relationship varies from adolescence to young adulthood, after accounting for both alcohol and nicotine exposure. The sample was drawn from the Social and Emotional Contexts of Adolescent Smoking Patterns Study which measured smoking, nicotine dependence, alcohol use and alcohol related problems over 6 assessment waves spanning 6 years. Analyses were based on repeated assessment of 864 participants reporting some smoking and drinking 30 days prior to individual assessment waves. Mixed-effects regression models were estimated to examine potential time, smoking and/or alcohol varying effects in the association between alcohol problems and nicotine dependence. Inter-individual differences in mean levels of alcohol problems and within subject changes in alcohol problems from adolescence to young adulthood were each significantly associated with nicotine dependence symptoms over and above levels of smoking and drinking behaviour. This association was consistent across both time and increasing levels of smoking and drinking. Alcohol related problems are a consistent risk factor for nicotine dependence over and above measures of drinking and smoking and this association can be demonstrated from the earliest experiences with smoking in adolescents, through the establishment of more regular smoking patterns across the transition to young adulthood. These findings add to accumulating evidence suggesting that smoking and drinking may be related through a mechanism that cannot be wholly accounted for by exposure to either substance.

Structure and Dynamics of Ionic Liquid [MMIM][Br] Confined in Hydrophobic and Hydrophilic Porous Matrices: A Molecular Dynamics Simulation Study.

PubMed

Sharma, Anirban; Ghorai, Pradip Kr

2016-11-17

The effects of confinement on the structural and dynamical properties of the ionic liquid (IL) 1,3-dimethylimidazolium bromide ([MMIM][Br]) have been investigated by molecular dynamics simulations. We used zeolite faujasite (NaY) as a hydrophilic confinement and dealuminated faujasite (DAY) as a hydrophobic confinement. The presence of an extra framework cation, [Na + ], in NaY makes the host hydrophilic, whereas DAY, with no extra framework cation, is hydrophobic. Although both NaY and DAY have almost similar structures, the IL showed markedly different structural and dynamical properties in these confinements and in bulk. In the confinements, the cation-cation radial distribution function, which strongly depends on temperature, exhibits a layer-like structure, whereas in bulk, it shows a liquid-like structure that hardly depends on temperature. Although the interaction between [MMIM] + and Br - in DAY is stronger than that in both NaY and bulk, the strength of the interaction between them is almost invariant with temperature. Both [MMIM] + and Br - strongly interact with Na + of the host, and their interaction strongly depends on temperature, whereas the interaction of the IL with Si and O is very weak and invariant with temperature. In bulk, the self-diffusion coefficient, [D], of both [MMIM] + and Br - increases exponentially with temperature, and the D of the cation is slightly higher than that of the anion at all studied temperatures, whereas in the confinements, [MMIM] + moves much faster than Br - . For example, in the hydrophilic confinement, the D of the cation is 20-30 times higher than that of the anion. The D of both the ions decreases significantly in the confinements as compared to that in bulk. During diffusion, [MMIM] + diffuses closer to the inner surface in the hydrophilic confinement than that in the hydrophobic confinement. The diffusion pathway imperceptibly depends on temperature but strongly depends on the nature of the confinement. The self part of the time-dependent van Hoove correlation function of [MMIM] + in the hydrophilic confinement shows a larger deviation from its Gaussian form than that in the hydrophobic confinement at all temperatures, indicating that the long-time dynamics of [MMIM] + in NaY is more heterogeneous than that in DAY. Although the orientational relaxation time scales of [MMIM] + in the confinements significantly slowed as compared to those in bulk, confinement does not affect the librational motion of the collective hydrogen-bond network present in the IL.

The Failure of Feminist Epistemology

ERIC Educational Resources Information Center

Shelton, Jim D.

2006-01-01

Mankind has generally done its best to pursue the truth, since the beginning of time. Given the unlikely tenets of their ideology, though, today's feminists see the need to distort this pursuit. Therefore, radicals in that camp argue that the sex of the thinker is significant to the idea, that truth depends on its social construction, or that…

The Gains from Vertical Scaling

ERIC Educational Resources Information Center

Briggs, Derek C.; Domingue, Ben

2013-01-01

It is often assumed that a vertical scale is necessary when value-added models depend upon the gain scores of students across two or more points in time. This article examines the conditions under which the scale transformations associated with the vertical scaling process would be expected to have a significant impact on normative interpretations…

Staff Development Needs in Pakistan Higher Education

ERIC Educational Resources Information Center

Ullah, Muhammad Hameed; Khan, Muhammad Naeem Ullah; Murtaza, Ali; Ud Din, Muhammad Naseer

2011-01-01

Staff development is very significant for the achievement of overall goals of higher education in Pakistan. The success of innovations depends largely upon the skills of instructors; but in Pakistan, the people with a simple masters degree (without any pedagogical training) are inducted as teaching staff at the university level, so it is time to…

Constructing Alternate Assessment Cohorts: An Oregon Perspective. Research Brief 3

ERIC Educational Resources Information Center

Saven, Jessica L.; Farley, Dan; Tindal, Gerald

2013-01-01

Longitudinally modeling the growth of students with significant cognitive disabilities (SWSCDs) on alternate assessments based on alternate achievement standards (AA-AAS) presents many challenges for states. The number of students in Grades 3-8 who remain in a cohort group varies over time, depending on the methods used to construct the…

Inoculation of Scrapie with the Self-Assembling RADA-Peptide Disrupts Prion Accumulation and Extends Hamster Survival

USDA-ARS?s Scientific Manuscript database

Intercerebral inoculation of 263K Scrapie brain homogenate (PrPsc) with a self-assembling RADA-peptide (RADA) significantly delayed disease onset and increased hamster survival. Time of survival was dependent on the dose of RADA and pre-incubation with PrPsc prior to inoculation. RADA treatment resu...

Prolonged forearm ischemia attenuates endothelium-dependent vasodilatation and plasma nitric oxide metabolites in overweight middle-aged men.

PubMed

Aboo Bakkar, Zainie; Fulford, Jonathan; Gates, Phillip E; Jackman, Sarah R; Jones, Andrew M; Bond, Bert; Bowtell, Joanna L

2018-05-21

Repeated cycles of endothelial ischemia-reperfusion injury and the resulting respiratory burst contribute to the irreversible pathophysiology of vascular diseases, and yet, the effects of ischemia reperfusion on vascular function, oxidative stress, and nitric oxide (NO) bioavailability have not been assessed simultaneously. Therefore, this study sought to examine the effects of prolonged forearm occlusion and subsequent reperfusion on NO-dependent brachial artery endothelial function. Flow-mediated dilatation was measured at baseline and 15, 30, and 45 min after 20-min forearm occlusion in 14 healthy, but physically inactive middle-aged men (53.7 ± 1.2 years, BMI: 28.1 ± 0.1 kg m -2 ). Venous blood samples collected from the occluded arm were analyzed for NO metabolites and markers of oxidative stress. FMD was significantly depressed after the prolonged occlusion compared to baseline, with a significant reduction 15-min post-occlusion (6.6 ± 0.7 to 2.9 ± 0.4%, p < 0.001); FMD remained depressed after 30 min (4.1 ± 0.6%, p = 0.001), but was not significantly different to baseline after 45-min recovery (5.4 ± 0.7%, p = 0.079). Plasma nitrate (main time effect: p = 0.015) and nitrite (main time effect: p = 0.034) concentrations were significantly reduced after prolonged occlusion. Plasma catalase activity was significantly elevated at 4- (p = 0.016) and 45-min (p = 0.001) post-occlusion, but plasma peroxiredoxin 2 and protein carbonyl content did not change. Prolonged forearm occlusion resulted in acute impairment of endothelium-dependent vasodilatation of the brachial artery for at least 30 min after reperfusion. We demonstrate that this vascular dysfunction is associated with oxidative stress and reduced NO bioavailability following reperfusion.

Time- and polarity-dependent proteomic changes associated with homeostatic scaling at central synapses

PubMed Central

Schanzenbächer, Christoph T

2018-01-01

In homeostatic scaling at central synapses, the depth and breadth of cellular mechanisms that detect the offset from the set-point, detect the duration of the offset and implement a cellular response are not well understood. To understand the time-dependent scaling dynamics we treated cultured rat hippocampal cells with either TTX or bicucculline for 2 hr to induce the process of up- or down-scaling, respectively. During the activity manipulation we metabolically labeled newly synthesized proteins using BONCAT. We identified 168 newly synthesized proteins that exhibited significant changes in expression. To obtain a temporal trajectory of the response, we compared the proteins synthesized within 2 hr or 24 hr of the activity manipulation. Surprisingly, there was little overlap in the significantly regulated newly synthesized proteins identified in the early- and integrated late response datasets. There was, however, overlap in the functional categories that are modulated early and late. These data indicate that within protein function groups, different proteomic choices can be made to effect early and late homeostatic responses that detect the duration and polarity of the activity manipulation. PMID:29447110

Effect of Mn doping on the temperature-dependent anomalous giant dielectric behavior of CaCu3Ti4O12

NASA Astrophysics Data System (ADS)

Kim, C. H.; Jang, Y. H.; Seo, S. J.; Song, C. H.; Son, J. Y.; Yang, Y. S.; Cho, J. H.

2012-06-01

We report dielectric properties and dielectric relaxation behaviors of Mn-substituted CaCu3Ti4O12 (CCTO) on Cu sites. While CCTO exhibits the giant dielectric constant and low dielectric loss in a wide temperature range, drastic suppression of the dielectric constant in Mn-doped CCTO (CCMTO) samples have been observed in temperature and frequency dependencies of dielectric properties with two possible origins as Mn doping increases. The observed suppression of dielectric response in the low Mn doping differs from the heavy doping of Mn in CCMTO samples. The low-Mn-doped CCMTO samples (x=0.01 and 0.02) show that the relaxation time and the activation energy Ea were slightly reduced due to a decreased contribution from the density of the dipolar effect. However, in heavily doped CCMTO samples (x=0.03, 0.04, and 0.05), the dielectric response, relaxation time, and Ea were significantly decreased, suggesting Mn doping plays a significant role in the destruction of the intrinsic dipolar effect.

Tanshinones extend chronological lifespan in budding yeast Saccharomyces cerevisiae.

PubMed

Wu, Ziyun; Song, Lixia; Liu, Shao Quan; Huang, Dejian

2014-10-01

Natural products with anti-aging property have drawn great attention recently but examples of such compounds are exceedingly scarce. By applying a high-throughput assay based on yeast chronological lifespan measurement, we screened the anti-aging activity of 144 botanical materials and found that dried roots of Salvia miltiorrhiza Bunge have significant anti-aging activity. Tanshinones isolated from the plant including cryptotanshione, tanshinone I, and tanshinone IIa, are the active components. Among them, cryptotanshinone can greatly extend the budding yeast Saccharomyces cerevisiae chronological lifespan (up to 2.5 times) in a dose- and the-time-of-addition-dependent manner at nanomolar concentrations without disruption of cell growth. We demonstrate that cryptotanshinone prolong chronological lifespan via a nutrient-dependent regime, especially essential amino acid sensing, and three conserved protein kinases Tor1, Sch9, and Gcn2 are required for cryptotanshinone-induced lifespan extension. In addition, cryptotanshinone significantly increases the lifespan of SOD2-deleted mutants. Altogether, those data suggest that cryptotanshinone might be involved in the regulation of, Tor1, Sch9, Gcn2, and Sod2, these highly conserved longevity proteins modulated by nutrients from yeast to humans.

Preliminary study on pharmacokinetics of dacarbazine and fotemustine in glioblastoma multiforme patients does not indicate gender-specific differences.

PubMed

Fazeny-Dörner, Barbara; Mader, Robert M; Piribauer, Maria; Rizovski, Blanka; Stögermaier, Barbara; Marosi, Christine

2004-06-01

Twelve patients (six female and six male) with histologically proven glioblastoma multiforme were investigated during the administration of the first cycle of dacarbazine (D; 200 mg/m) and fotemustine (F; 100 mg/m). In total, 18 blood samples were collected for pharmacokinetic analysis (maximum plasma concentration, area under the concentration-time curve and total clearance) of D and F at 14 time points during therapy. D, its metabolite 5-aminoimidazole-4-carboxamide and F were evaluated by reversed-phase HPLC. For statistical calculations, groups were compared by the non-parametric Wilcoxon test. p<0.05 was considered statistically significant. No significant gender-dependent differences were observed in the pharmacokinetics of D and F. An additional response re-evaluation of 100 patients (50 female and 50 male) with glioblastoma multiforme, treated at our institution with D and F, gave no hint of any gender-dependent different response rates. We conclude that there is no evidence, neither from pharmacokinetic nor from our clinical data, to consider different dosages of D and F in female and male patients with glioblastoma multiforme.