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  1. Intermittent binge alcohol exposure during the periadolescent period induces spatial working memory deficits in young adult rats.

    PubMed

    Schulteis, Gery; Archer, Clay; Tapert, Susan F; Frank, Lawrence R

    2008-09-01

    Human and animal studies suggest adolescence is a period of heightened sensitivity to adverse cognitive sequelae of alcohol exposure. The present study assessed the effects of intermittent binge ethanol intoxication during the periadolescent period of Wistar rats on subsequent performance in a Morris water maze spatial navigation task. On postnatal days 32-56, rats were exposed to ethanol or air 3 days/week via vapor inhalation chambers. Acquisition of spatial navigation was assessed beginning 5 days after the final day of exposure, with 3 days of training in the Morris Water maze (four trials per day spaced at 90-s intertrial intervals [ITIs]). Rats were placed into the water maze at one of four positions along the perimeter, with a different release position to begin each trial. A probe trial assessed retention of platform location on the day after the final set of training trials. Four days after this probe trial, rats entered a working memory phase in which the platform was in a new location each day and a variable ITI of 1, 2, or 4 h was inserted between Trials 1 and 2; Trials 3 and 4 followed at 90-s intervals after Trial 2 on each day. The "savings" in latency to find the platform and distance traveled before finding it from Trial 1 to Trial 2 on each day served as an index of working memory. Ethanol-exposed rats showed similar acquisition of spatial navigation as control rats during training, as well as similar retention of platform location during the probe trial. However, rats exposed to average blood alcohol level (BAL) >200 mg% showed accelerated forgetting, with decreased retention of platform location at the 2-h ITI (P < .05), compared to control rats. Therefore, a 4-week history of intermittent ethanol exposure at BAL in excess of 200 mg% during periadolescence led to a working memory deficit in young adult rats, demonstrated by accelerated forgetting of novel information. These behavioral data are consistent with findings from adolescent human

  2. Persistent expression of methamphetamine-induced CTA in periadolescent rats.

    PubMed

    Harrod, Steven B; Lacy, Ryan T; Ballina, Lauren E

    2010-10-01

    It is well documented that the transition from periadolescence to adulthood produces profound changes in motivated behavior, and furthermore, attenuates the aversive experience of abused drugs. Little is known, however, about adolescent memory for the conditioned aversive effects of abused drugs following retention intervals that span this developmental transition. The present experiment investigated methamphetamine-induced conditioned taste aversion (CTA) in periadolescent rats to determine if the magnitude of conditioning was altered following retention intervals that extend to adulthood. Rats consumed saccharin (0.1%, w/v) and were immediately injected with saline or methamphetamine (3.0mg/kg) either once (PND 40) or three times (PND 38-40), and memory was assessed one or 50 days later on post natal days 41 or 90, respectively. Rats exhibited robust methamphetamine-induced CTA one and 50 days after conditioning, and the strength of responding did not change as a function of retention interval, regardless if animals were trained with one or three saccharin-methamphetamine pairings. These findings indicate that the expression of memory for the aversive effects of methamphetamine was resistant to degradation throughout the developmental period of periadolescence to adulthood. (c) 2010 Elsevier Inc. All rights reserved.

  3. Exposure to nicotine during periadolescence or early adulthood alters aversive and physiological effects induced by ethanol.

    PubMed

    Rinker, Jennifer A; Hutchison, Mary Anne; Chen, Scott A; Thorsell, Annika; Heilig, Markus; Riley, Anthony L

    2011-07-01

    The majority of smokers begin their habit during adolescence, which often precedes experimentation with alcohol. Interestingly, very little preclinical work has been done examining how exposure to nicotine during periadolescence impacts the affective properties of alcohol in adulthood. Understanding how periadolescent nicotine exposure influences the aversive effects of alcohol might help to explain why it becomes more acceptable to this preexposed population. Thus, Experiment 1 exposed male Sprague Dawley rats to either saline or nicotine (0.4mg/kg, IP) from postnatal days 34 to 43 (periadolescence) and then examined changes in the aversive effects of alcohol (0, 0.56, 1.0 and 1.8g/kg, IP) in adulthood using the conditioned taste aversion (CTA) design. Changes in blood alcohol concentration (BAC) as well as alcohol-induced hypothermia and locomotor suppression were also assessed. To determine if changes seen were specific to nicotine exposure during periadolescence, the procedures were replicated in adults (Experiment 2). Preexposure to nicotine during periadolescence attenuated the acquisition of the alcohol-induced CTAs (at 1.0g/kg) and the hypothermic effects of alcohol (1.0g/kg). Adult nicotine preexposure produced similar attenuation in alcohol's aversive (at 1.8g/kg) and hypothermic (1.8g/kg) effects. Neither adolescent nor adult nicotine preexposure altered BACs or alcohol-induced locomotor suppression. These results suggest that nicotine may alter the aversive and physiological effects of alcohol, regardless of the age at which exposure occurs, possibly increasing its overall reinforcing value and making it more likely to be consumed.

  4. Exposure to Nicotine During Periadolescence or Early Adulthood Alters Aversive and Physiological Effects Induced by Ethanol

    PubMed Central

    Rinker, Jennifer A.; Hutchison, Mary Anne; Chen, Scott A.; Thorsell, Annika; Heilig, Markus; Riley, Anthony L.

    2011-01-01

    The majority of smokers begin their habit during adolescence, which often precedes experimentation with alcohol. Interestingly, very little preclinical work has been done examining how exposure to nicotine during periadolescence impacts the affective properties of alcohol in adulthood. Understanding how periadolescent nicotine exposure influences the aversive effects of alcohol might help to explain why it becomes more acceptable to this preexposed population. Thus, Experiment 1 exposed male Sprague Dawley rats to either saline or nicotine (0.4 mg/kg, IP) from postnatal day 34 to 43 (periadolescence) and then examined changes in the aversive effects of alcohol (0, 0.56, 1.0 and 1.8 g/kg, IP) in adulthood using the conditioned taste aversion (CTA) design. Changes in blood alcohol concentration (BAC) as well as alcohol-induced hypothermia and locomotor suppression were also assessed. To determine if changes seen were specific to nicotine exposure during periadolescence, the procedures were replicated in adults (Experiment 2). Preexposure to nicotine during periadolescence attenuated the acquisition of the alcohol-induced CTAs (at 1.0 g/kg) and the hypothermic effects of alcohol (1.0 g/kg). Adult nicotine preexposure produced similar attenuation in alcohol's aversive (at 1.8 g/kg) and hypothermic (1.8 g/kg) effects. Neither adolescent nor adult nicotine preexposure altered BACs or alcohol-induced locomotor suppression. These results suggest that nicotine can alter the aversive and physiological effects of alcohol, regardless of the age at which exposure occurs, possibly increasing its overall reinforcing value and making it more likely to be consumed. PMID:21420998

  5. Intermittent Voluntary Ethanol Drinking during Periadolescence Impairs Adult Spatial Learning after a Long Abstinence Period in Rats

    ERIC Educational Resources Information Center

    Diaz, Ana; Garcia-Burgos, David; Manrique, Tatiana; Gonzalez, Felisa; Gallo, Milagros

    2011-01-01

    Although previous findings point to the long-term impact of ethanol exposure during periadolescence on hippocampal-dependent learning tasks, comparisons considering different onset and exposure periods during this developmental range of ages are still needed. The aim of this experiment was to determine whether intermittent voluntary chronic…

  6. Effect of ascorbic acid on the monosodium glutamate-induced neurobehavioral changes in periadolescent rats.

    PubMed

    Narayanan, Sareesh Naduvil; Kumar, Raju Suresh; Paval, Jaijesh; Nayak, Satheesha

    2010-01-01

    In the current study we evaluated adverse effects of monosodium glutamate (MSG) on memory formation and its retrieval as well as the role of ascorbic acid (Vitamin-C) in prevention of MSG-induced alteration of neurobehavioral performance in periadolescent rats. Healthy male albino Wistar rats (4-6 weeks old), were randomly allotted in four groups. Group I: normal control, who remained in their homecage throughout the experimental period. Group II: vehicle control, who were orally administered with normal saline for three weeks. Group III: MSG, who were orally administered with aqueous solution of MSG (2 mg/g b.w/day), for three weeks. Group IV: MSG+AA, who were administered with aqueous solution of MSG, and subsequently by ascorbic acid (100 mg/kg b.w/day) orally for three weeks. After the experimental period, all animals from all groups were first tested for anxiety followed by passive avoidance behavior. MSG significantly altered the neurobehavioral performance in rats. The alteration manifested as less time spent on the open arm during the EPM test and shorter entrance latency to the dark compartment during the passive avoidance task. All behavioral changes were significantly prevented by simultaneous administration of ascorbic acid with MSG. The present data point to the neuroprotective role of ascorbic acid. The ascorbic acid can be used as a therapeutic agent in various cognitive deficits (Fig. 5, Ref. 25). Full Text (Free, PDF) www.bmj.sk.

  7. Narrow band quantitative and multivariate electroencephalogram analysis of peri-adolescent period

    PubMed Central

    2012-01-01

    Background The peri-adolescent period is a crucial developmental moment of transition from childhood to emergent adulthood. The present report analyses the differences in Power Spectrum (PS) of the Electroencephalogram (EEG) between late childhood (24 children between 8 and 13 years old) and young adulthood (24 young adults between 18 and 23 years old). Results The narrow band analysis of the Electroencephalogram was computed in the frequency range of 0–20 Hz. The analysis of mean and variance suggested that six frequency ranges presented a different rate of maturation at these ages, namely: low delta, delta-theta, low alpha, high alpha, low beta and high beta. For most of these bands the maturation seems to occur later in anterior sites than posterior sites. Correlational analysis showed a lower pattern of correlation between different frequencies in children than in young adults, suggesting a certain asynchrony in the maturation of different rhythms. The topographical analysis revealed similar topographies of the different rhythms in children and young adults. Principal Component Analysis (PCA) demonstrated the same internal structure for the Electroencephalogram of both age groups. Principal Component Analysis allowed to separate four subcomponents in the alpha range. All these subcomponents peaked at a lower frequency in children than in young adults. Conclusions The present approaches complement and solve some of the incertitudes when the classical brain broad rhythm analysis is applied. Children have a higher absolute power than young adults for frequency ranges between 0-20 Hz, the correlation of Power Spectrum (PS) with age and the variance age comparison showed that there are six ranges of frequencies that can distinguish the level of EEG maturation in children and adults. The establishment of maturational order of different frequencies and its possible maturational interdependence would require a complete series including all the different ages. PMID

  8. N-acetylcysteine attenuates nicotine-induced kindling in female periadolescent rats.

    PubMed

    Okamura, Adriana Mary Nunes Costa; Gomes, Patrícia Xavier L; de Oliveira, Gersilene V; de Araújo, Fernanda Yvelize R; Tomaz, Viviane S; Chaves Filho, Adriano José Maia; de Sousa, Francisca Cléa F; Vasconcelos, Silvânia Maria Mendes; de Lucena, David Freitas; Macêdo, Danielle

    2016-06-03

    Kindling is a form of behavioral sensitization that is related to the progression of several neuropsychiatric disorders such as bipolar disorder. We recently demonstrated that female periadolescent rats are more vulnerable to nicotine (NIC)-induced kindling than their male counterparts. Furthermore, we evidenced that decreases in brain antioxidative defenses may contribute to this gender difference. Here we aimed to determine the preventive effects of the antioxidant N-acetyl cysteine (NAC) against NIC-kindling in female periadolescent rats. To do this female Wistar rats at postnatal day 30 received repeated injections of NIC 2mg/kg, i.p. every weekday for up to 19 days. NAC90, 180 or 270 mg/kg, i.p. was administered 30 min before NIC. The levels of glutathione (GSH), superoxide dismutase (SOD) activity, lipid peroxidation (LP) and nitrite were determined in the prefrontal cortex (PFC), hippocampus (HC) and striatum (ST). The development of kindling occurred at a median time of 16.5 days with 87.5% of NIC animals presenting stage 5 seizures in the last day of drug administration. NAC270 prevented the occurrence of kindling. NIC-kindled animals presented decreased levels of GSH and increased LP in the PFC, HC and ST, while SOD activity was decreased in the ST. NAC180 or 270 prevented the alterations in GSH induced by NIC, but only NAC270 prevented the alterations in LP. Nitrite levels increased in the ST of NAC270 pretreated NIC-kindled animals. Taken together we demonstrated that NAC presents anti-kindling effects in female animals partially through the restoration of oxidative alterations. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Periadolescent exposure to the NMDA receptor antagonist MK-801 impairs the functional maturation of local GABAergic circuits in the adult prefrontal cortex.

    PubMed

    Thomases, Daniel R; Cass, Daryn K; Tseng, Kuei Y

    2013-01-02

    A developmental disruption of prefrontal cortical inhibitory circuits is thought to contribute to the adolescent onset of cognitive deficits observed in schizophrenia. However, the developmental mechanisms underlying such a disruption remain elusive. The goal of this study is to examine how repeated exposure to the NMDA receptor antagonist dizocilpine maleate (MK-801) during periadolescence [from postnatal day 35 (P35) to P40] impacts the normative development of local prefrontal network response in rats. In vivo electrophysiological analyses revealed that MK-801 administration during periadolescence elicits an enduring disinhibited prefrontal local field potential (LFP) response to ventral hippocampal stimulation at 20 Hz (beta) and 40 Hz (gamma) in adulthood (P65-P85). Such a disinhibition was not observed when MK-801 was given during adulthood, indicating that the periadolescent transition is indeed a sensitive period for the functional maturation of prefrontal inhibitory control. Accordingly, the pattern of prefrontal LFP disinhibition induced by periadolescent MK-801 treatment resembles that observed in the normal P30-P40 prefrontal cortex (PFC). Additional pharmacological manipulations revealed that these developmentally immature prefrontal responses can be mimicked by single microinfusion of the GABA(A) receptor antagonist picrotoxin into the normal adult PFC. Importantly, acute administration of the GABA(A)-positive allosteric modulator Indiplon into the PFC reversed the prefrontal disinhibitory state induced by periadolescent MK-801 to normal levels. Together, these results indicate a critical role of NMDA receptors in regulating the periadolescent maturation of GABAergic networks in the PFC and that pharmacologically induced augmentation of local GABA(A)-receptor-mediated transmission is sufficient to overcome the disinhibitory prefrontal state associated with the periadolescent MK-801 exposure.

  10. Disruption of peri-adolescent endocannabinoid signaling modulates adult neuroendocrine and behavioral responses to stress in male rats.

    PubMed

    Lee, Tiffany T-Y; Hill, Matthew N; Hillard, Cecilia J; Gorzalka, Boris B

    2015-12-01

    The endocannabinoid (eCB) system is known to regulate neural, endocrine and behavioral responses to stress in adults; however there is little knowledge regarding how this system governs the development and maturation of these responses. Previous work has reported dynamic and time-specific changes in CB1 receptor expression, N-arachidonylethanolamine (AEA) content and fatty acid amide hydrolase (FAAH) activity within corticolimbic structures throughout the peri-adolescent period. To examine whether fluctuations in adolescent eCB activity contribute to the development of adult stress responsivity and emotionality, we treated male Sprague-Dawley rats daily with the CB1R antagonist, AM-251 (5 mg/kg), or vehicle between post-natal days (PND) 35-45. Following this treatment, emotional behavior, HPA axis stress reactivity and habituation to repeated restraint stress, as well as corticolimbic eCB content were examined in adulthood (PND 75). Behaviorally, AM-251-treated males exhibited more active stress-coping behavior in the forced swim test, greater risk assessment behavior in the elevated plus maze and no significant differences in general motor activity. Peri-adolescent AM-251 treatment modified corticosterone habituation to repeated restraint exposure compared to vehicle. Peri-adolescent CB1R antagonism induced moderate changes in adult corticolimbic eCB signaling, with a significant decrease in amygdalar AEA, an increase in hypothalamic AEA and an increase in prefrontal cortical CB1R expression. Together, these data indicate that peri-adolescent endocannabinoid signaling contributes to the maturation of adult neurobehavioral responses to stress. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Periadolescent nicotine exposure causes heterologous sensitization to cocaine reinforcement.

    PubMed

    McMillen, Brian A; Davis, Barbara J; Williams, Helen L; Soderstrom, Ken

    2005-02-21

    There is increasing concern that abuse of tobacco during periadolescence increases the potential for later abuse of other drugs. To test this hypothesis, Sprague-Dawley rats received once-daily injections of either water or 0.4 mg/kg nicotine from postnatal day 35 through 44. Beginning on postnatal day 80, animals were tested in a 12-day cocaine-induced conditioned place preference (CPP) paradigm. Prior nicotine treatment enhanced the dose-response to cocaine. CPP training with 3.0 mg/kg i.p. cocaine increased time in drug-paired chambers by 50% in control rats and 94% in nicotine-exposed animals. Thus, periadolescent nicotine exposure produced long-term sensitization to an indirect-acting dopamine agonist.

  12. Short- and Long-Term Effects of Interleukin-2 Treatment on the Sensitivity of Periadolescent Female Mice to Interleukin-2 and Dopamine Uptake Inhibitor

    PubMed Central

    Rankin, James S.; Zalcman, Steven S.; Zhu, Youhua; Siegel, Allan

    2013-01-01

    Interleukin (IL)-2, a T-helper 1 (Th1) cell-derived cytokine, which potently modulates dopamine activity and neuronal excitability in mesolimbic structures, is linked with pathological outcomes (e.g., schizophrenia, depression, etc.) that at least partly reflect alterations in central dopaminergic processes. It has been suggested that dopamine neurons undergo pruning during adolescence and abnormalities in pruning predispose individuals to behavioral disorders. Since IL-2 is known as a neurodevelopmental factor affecting associated behavioral processes, the present study tested whether IL-2 can modulate stereotypic behaviors in both the periadolescent and adult periods. This study determined whether IL-2 treatment would produce long-lasting changes in sensitivity to a later challenge with IL-2 or GBR 12909, a highly selective dopamine uptake inhibitor. Four experiments were conducted. Firstly, a decrease in novelty-induced stereotypic behavior was observed in BALB/c periadolescent mice (38 days of age) following IL-2 administration (0.4 µg/2 ml) relative to vehicle control. In the second experiment, an initial dose of IL-2 was given in the periadolescent period, but did not affect rearing responses. A second dose of IL-2 given to the animals 30 days later as adults, resulted in a significant increase in rearing behaviors relative to control animals. In the third experiment, separate groups of experimental and control mice were administered GBR 12909, a highly selective dopamine reuptake inhibitor, 30 days following treatment with either IL-2 or vehicle. It was noted that this experimental group, which initially received IL-2, exhibited stereotypy, as evidenced by increased sniffing behavior. A fourth experiment revealed that IL-2 administered in periadolesecence and adulthood had no effect on other motor responses, indicating that IL-2 selectively modulates selective stereotypic behaviors. The results provide evidence, for the first time, that long-term changes in

  13. Attenuated incubation of cocaine seeking in male rats trained to self-administer cocaine during periadolescence.

    PubMed

    Li, Chen; Frantz, Kyle J

    2009-07-01

    Although onset of drug use during adolescence appears to increase long-term vulnerability to drug dependence in humans, relatively little is known about extinction and reinstatement of drug seeking after periadolescent onset of drug self-administration in laboratory animals. Furthermore, although cue-induced reinstatement of cocaine seeking increases progressively during abstinence from cocaine self-administration in adult subjects, this "incubation of cocaine craving" remains unexplored after adolescent drug intake in animal models. We allowed periadolescent (postnatal day (PND) 35 at start) and adult (PND 83-95 at start) male Wistar rats to self-administer cocaine (0.36 mg/kg/infusion) in 2-h daily sessions on a fixed ratio 1 schedule of reinforcement over 14 days. Then, we compared extinction and cue-induced or cocaine priming-induced reinstatement (10 mg/kg cocaine, intraperitoneal) of cocaine seeking in both age groups after 30 days of abstinence in home cages. In separate cohorts, we tested for time-dependent increases in cue-induced reinstatement over approximately 1, 14, 30, or 60 days of abstinence in both age groups. Adolescent and adult rats self-administered similar amounts of cocaine. Subsequent cue-induced reinstatement was lower in the adolescent-onset group after a 30-day abstinence period, but cocaine priming-induced reinstatement did not differ across ages. Also, extinction responding and time-dependent increases in cue-induced reinstatement (incubation) were less pronounced in rats that took cocaine as adolescents compared with adults. Surprisingly, these results may reflect resistance among adolescent subjects to some enduring effects of drug self-administration, such as reward learning.

  14. Sex and age specific effects of delta-9-tetrahydrocannabinol during the periadolescent period in the rat: The unique susceptibility of the prepubescent animal.

    PubMed

    Silva, Lindsay; Black, Rita; Michaelides, Michael; Hurd, Yasmin L; Dow-Edwards, Diana

    Adolescents who use marijuana are more likely to exhibit anxiety, depression, and other mood disorders, including psychotic-like symptoms. Additionally, the age at onset of use and the stress history of the individual can affect responses to cannabis. To examine the effect of early life experience on adolescent Δ-9-tetrahydrocannabinol (THC) exposure, we exposed adolescent (postnatal day (P) 29-38) male and female rats, either shipped from a supplier or born in our vivarium, to once daily injections of 3mg/kg THC. Our findings suggest that males are more sensitive to the anxiolytic and antidepressant effects of THC, as measured by the elevated plus maze (EPM) and forced swim test (FST), respectively, than females. Exposure to the FST increased plasma corticosterone levels, regardless of drug treatment or origin and females had higher levels than males overall. Shipping increased THC responses in females (acoustic startle habituation) and in males (latency to immobility in FST). No significant effects of THC or shipping on pre-pulse inhibition were observed. Due to differences in timing of puberty in males and females during the P29-38 period of THC treatment, we also dosed female rats between P21-30 (pre-puberty) and male rats between P39-48 (puberty). Pre-pubertal animals showed reductions in anxiety on the EPM, an effect that was not seen in animals treated during puberty. These results suggest that both sexes are more susceptible to changes in emotional behavior when THC exposure occurs just prior to the onset of puberty. Within the animals dosed from P29-38, THC increased cannabinoid receptor 1 (CB1R) mRNA expression and tended to decrease CP55,940 stimulated [(35)S]GTPγS binding in the central amygdala only of females. Therefore, early stress enhances THC responses in males (in FST) and females (ASR habituation), THC alters CB1R expression and function in females only and prepubescent rats are generally more responsive to THC than pubertal rats. In summary

  15. Periadolescent rats (P41-50) exhibit increased susceptibility to D-methamphetamine-induced long-term spatial and sequential learning deficits compared to juvenile (P21-30 or P31-40) or adult rats (P51-60).

    PubMed

    Vorhees, Charles V; Reed, Tracy M; Morford, LaRonda L; Fukumura, Masao; Wood, Sandra L; Brown, Carrie A; Skelton, Matthew R; McCrea, Anne E; Rock, Stephanie L; Williams, Michael T

    2005-01-01

    We have previously shown that P11-20 treatment with d-methamphetamine (MA) induces impaired spatial navigation in the Morris water maze (MWM), whereas P1-10 treatment does not. Little is known about the long-term behavioral consequences of MA during juvenile, adolescent, and early adult brain development. In dose-response experiments, we tested successive 10-day intervals of exposure to MA in rats (P21-30, P31-40, P41-50, and P51-60; four doses per day). MA dosing prior to P21 produces little or no toxicity; however, we observed an increased toxicity with advancing age. Across-age comparisons revealed no MWM acquisition or Cincinnati water maze (CWM) effects after MA treatment on P21-30 (2.5-10 mg/kg/dose), P31-40 (1.25-7.5 mg/kg/dose), or P51-60 (1.25-5.0 mg/kg/dose); however, significantly impaired MWM acquisition was observed after P41-50 MA treatment at the highest dose (6.25 mg/kg/dose). Learning in the CWM was also impaired in this group. No effects were seen at 1.25, 2.5, or 5 mg/kg/dose following P41-50 MA treatment. MWM reversal learning trials after P41-50 treatment showed a trend towards longer latency in all MA dose groups, but no effect on double-reversal trials. Reversal and double-reversal also showed no effects at the other exposure ages. No differences in straight channel swimming or cued learning in the MWM were seen after MA treatment at any exposure age. P41-50 is the periadolescent stage of brain development in rodents. The effects observed at this age may suggest a previously unrecognized period of susceptibility for MA-induced cognitive deficits.

  16. Chronic cannabinoid administration to periadolescent rats modulates the metabolic response to acute cocaine in the adult brain.

    PubMed

    Higuera-Matas, Alejandro; Soto-Montenegro, Maria Luisa; Montoya, Gonzalo L; García-Vázquez, Verónica; Pascau, Javier; Miguéns, Miguel; Del Olmo, Nuria; Vaquero, Juan José; García-Lecumberri, Carmen; Desco, Manuel; Ambrosio, Emilio

    2011-06-01

    To analyze brain metabolic response to acute cocaine in male and female Wistar rats with or without a history of cannabinoid exposure during periadolescence. The synthetic cannabinoid agonist CP 55,940 (CP) or its vehicle (VH), were administered to male and female rats during periadolescence. When these animals reached adulthood, saline and cocaine-induced changes in 2-deoxy-2-[¹⁸F]fluoro-D-: glucose (FDG) uptake were studied by positron emission tomography. The baseline (post-saline) metabolism in the septal nuclei was higher in CP-females than in VH-females, although septal metabolism was lower in CP-females after cocaine, reaching similar values to those of VH-females at baseline. Cocaine did not affect metabolism in VH-females. Periadolescent cannabinoid treatment did not influence baseline metabolism in males although cocaine reduced the FDG uptake in the dorsal striatum of males that received the VH but not CP. These results suggest that cannabinoids during periadolescence modify baseline and cocaine-evoked brain metabolism in a sex-dependent manner. In the case of CP-females, the involvement of septal metabolic alterations in their susceptibility to the rewarding effects of cocaine should be further investigated.

  17. Escalation of i.v. cocaine intake in peri-adolescent vs. adult rats selectively bred for high (HiS) vs. low (LoS) saccharin intake

    PubMed Central

    Holtz, Nathan A.; Carroll, Marilyn E.

    2013-01-01

    Rationale Adolescence marks a period of increased vulnerability to the development of substance use disorders. High sweet preference is a genetically mediated behavioral trait that also predicts vulnerability to substances of abuse. Previous research has shown that while adolescent rats selectively bred for high (HiS) saccharin intake acquire cocaine self-administration at the same rate as adult HiS rats, adolescent rats bred for low saccharin intake (LoS) acquire cocaine self-administration faster than adult LoS rats. Objectives To investigate the interaction of the addiction vulnerability factors of peri-adolescence and saccharin preference on cocaine-intake using an animal model of escalation of cocaine intake over 6-h/day sessions. Methods Peri-adolescent and adult HiS and LoS female rats self-administered i.v. cocaine (0.4 mg/kg/inf) during short-access (2-h/day) sessions for 2 days. Next, a long-access (6-h/day) period (LgA) commenced and lasted 16 days. Following LgA, session length was returned to 2-h/day for a second short access phase. Results LoS peri-adolescent rats escalated cocaine intake over the LgA period and consumed more drug than LoS adult rats; however, peri-adolescent and adult HiS rats consumed similar amounts of cocaine during this period. Additionally, adult HiS rats self-administered more cocaine than adult LoS rats during the LgA period, while there was no phenotypic difference between the rat lines during peri-adolescence for the LgA period. During the first short-access phase, peri-adolescent rats self-administered more cocaine than adult rats. Conclusions These results emphasize the importance of adolescent drug abuse prevention by illustrating that phenotypic protection from addiction may not be expressed until adulthood. PMID:23307070

  18. Escalation of i.v. cocaine intake in peri-adolescent vs. adult rats selectively bred for high (HiS) vs. low (LoS) saccharin intake.

    PubMed

    Holtz, Nathan A; Carroll, Marilyn E

    2013-05-01

    Adolescence marks a period of increased vulnerability to the development of substance use disorders. High sweet preference is a genetically mediated behavioral trait that also predicts vulnerability to substances of abuse. Previous research has shown that while adolescent rats selectively bred for high (HiS) saccharin intake acquire cocaine self-administration at the same rate as adult HiS rats, adolescent rats bred for low saccharin intake (LoS) acquire cocaine self-administration faster than adult LoS rats. This study was conducted to investigate the interaction of the addiction vulnerability factors of peri-adolescence and saccharin preference on cocaine intake using an animal model of escalation of cocaine consumption over 6-h/day sessions. Peri-adolescent and adult HiS and LoS female rats self-administered i.v. cocaine (0.4 mg/kg/inf) during short-access (2-h/day) sessions for 2 days. Next, a long-access (6-h/day) period (LgA) commenced and lasted 16 days. Following LgA, session length was returned to 2-h/day for a second short access phase. LoS peri-adolescent rats escalated cocaine intake over the LgA period and consumed more drug than LoS adult rats; however, peri-adolescent and adult HiS rats consumed similar amounts of cocaine during this period. Additionally, adult HiS rats self-administered more cocaine than adult LoS rats during the LgA period, while there was no phenotypic difference between the rat lines during peri-adolescence for the LgA period. During the first short-access phase, peri-adolescent rats self-administered more cocaine than adult rats. These results emphasize the importance of adolescent drug abuse prevention by illustrating that phenotypic protection from addiction may not be expressed until adulthood.

  19. Chronic nicotine differentially alters cocaine-induced locomotor activity in adolescent vs. adult male and female rats.

    PubMed

    Collins, Stephanie L; Izenwasser, Sari

    2004-03-01

    Tobacco use is prevalent in the adolescent population. It is a major concern because tobacco is highly addictive and has also been linked to illicit drug use. There is not much research, however, on the interaction between nicotine and other stimulant drugs in animal models of early adolescence. This study examined the effects of chronic nicotine alone and on cocaine-stimulated activity in male and female periadolescent rats compared to male and female adult rats. During the seven-day nicotine pretreatment period, nicotine increased locomotor activity in all groups compared to vehicle controls. Male and female adult rats and female periadolescent rats developed sensitization to the locomotor-activating effects of nicotine over the 7-day treatment period, while male periadolescent rats did not. All groups treated with nicotine, however, exhibited sensitization to nicotine-induced repetitive motion over the 7-day nicotine treatment period. On day 8, male periadolescent rats pretreated with nicotine were more markedly sensitized to the locomotor-activating effects of cocaine than male adult rats, while female rats pretreated with nicotine were not sensitized to cocaine. In contrast, male and female periadolescent rats, but not adult rats, had increased amounts of repetitive beam breaks induced by cocaine after nicotine pretreatment. Overall, it appears that cross-sensitization to cocaine is greater in periadolescent than in adult rats, and that males are more sensitized than females. Thus, it may be that nicotine use during adolescence carries a greater risk than during adulthood and that male adolescents may be particularly vulnerable to the risk of cocaine abuse after nicotine use. This information should be taken into account so as to help us better understand the development of drug addiction in adolescents compared to adults.

  20. Sex-specific effect of the anabolic steroid, 17α-methyltestosterone, on inhibitory avoidance learning in periadolescent rats

    PubMed Central

    Ramos-Pratts, Keyla; Rosa-González, Dariana; Pérez-Acevedo, Nivia L.; Cintrón-López, Dahima; Barreto-Estrada, Jennifer L.

    2013-01-01

    The illicit use of anabolic androgenic steroids (AAS) has gained popularity among adolescents in the last decade. However, although it is known that exposure to AAS impairs cognition in adult animal models, the cognitive effects during adolescence remain undetermined. An inhibitory avoidance task (IAT) was used to assess the effect of AAS (17α-methyltestosterone; 17α-meT-7.5 mg/kg) in male and female periadolescent rats. A single injection of 17α-meT immediately before the footshock produced significant impairment of inhibitory avoidance learning in males but not females. Generalized anxiety, locomotion, and risk assessment behaviors (RAB) were not affected. Our results show that exposure to a single pharmacological dose of 17α-meT during periadolescence exerts sex-specific cognitive effects without affecting anxiety. Thus, disruption of the hormonal milieu during this early developmental period might have negative impact on learning and memory. PMID:23792034

  1. Sex-specific effect of the anabolic steroid, 17α-methyltestosterone, on inhibitory avoidance learning in periadolescent rats.

    PubMed

    Ramos-Pratts, Keyla; Rosa-González, Dariana; Pérez-Acevedo, Nivia L; Cintrón-López, Dahima; Barreto-Estrada, Jennifer L

    2013-10-01

    The illicit use of anabolic androgenic steroids (AAS) has gained popularity among adolescents in the last decade. However, although it is known that exposure to AAS impairs cognition in adult animal models, the cognitive effects during adolescence remain undetermined. An inhibitory avoidance task (IAT) was used to assess the effect of AAS (17α-methyltestosterone; 17α-meT--7.5 mg/kg) in male and female periadolescent rats. A single injection of 17α-meT immediately before the footshock produced significant impairment of inhibitory avoidance learning in males but not females. Generalized anxiety, locomotion, and risk assessment behaviors (RAB) were not affected. Our results show that exposure to a single pharmacological dose of 17α-meT during periadolescence exerts sex-specific cognitive effects without affecting anxiety. Thus, disruption of the hormonal milieu during this early developmental period might have negative impact on learning and memory.

  2. Long-term exposure to oral methylphenidate or dl-amphetamine mixture in peri-adolescent rhesus monkeys: effects on physiology, behavior, and dopamine system development.

    PubMed

    Soto, Paul L; Wilcox, Kristin M; Zhou, Yun; Kumar, Anil; Ator, Nancy A; Riddle, Mark A; Wong, Dean F; Weed, Michael R

    2012-11-01

    The stimulants methylphenidate and amphetamine are used to treat children with attention deficit/hyperactivity disorder over important developmental periods, prompting concerns regarding possible long-term health impact. This study assessed the effects of such a regimen in male, peri-adolescent rhesus monkeys on a variety of cognitive/behavioral, physiological, and in vivo neurochemical imaging parameters. Twice daily (0900 and 1200 hours), for a total of 18 months, juvenile male monkeys (8 per group) consumed either an unadulterated orange-flavored solution, a methylphenidate solution, or a dl-amphetamine mixture. Doses were titrated to reach blood/plasma levels comparable to therapeutic levels in children. [¹¹C]MPH and [¹¹C]raclopride dynamic PET scans were performed to image dopamine transporter and D₂-like receptors, respectively. Binding potential (BP(ND)), an index of tracer-specific binding, and amphetamine-induced changes in BP(ND) of [¹¹C]raclopride were estimated by kinetic modeling. There were no consistent differences among groups on the vast majority of measures, including cognitive (psychomotor speed, timing, inhibitory control, cognitive flexibility), general activity, physiological (body weight, head circumference, crown-to-rump length), and neurochemical (ie, developmental changes in dopamine transporter, dopamine D₂ receptor density, and amphetamine-stimulated dopamine release were as expected). Cytogenetic studies indicated that neither drug was a clastogen in rhesus monkeys. Thus, methylphenidate and amphetamine at therapeutic blood/plasma levels during peri-adolescence in non-human primates have little effect on physiological or behavioral/cognitive development.

  3. Effects of ethanol exposure on subsequent acquisition and extinction of ethanol self-administration and expression of alcohol-seeking behavior in adult alcohol-preferring (P) rats: I. Periadolescent exposure.

    PubMed

    Rodd-Henricks, Zachary A; Bell, Richard L; Kuc, Kelly A; Murphy, James M; McBride, William J; Lumeng, Lawrence; Li, Ting-Kai

    2002-11-01

    The current study examined the effects of ethanol (EtOH) drinking during periadolescence on the subsequent acquisition and extinction of operant self-administration of EtOH and expression of alcohol-seeking behavior in adult alcohol-preferring (P) rats to test the hypothesis that alcohol drinking during periadolescence produces enduring alterations that enhance the reinforcing properties of EtOH. Periadolescent female P rats were given 24 hr free-choice access to 15% (v/v) EtOH starting at postnatal day (PND) 30 and ending on PND 60 or were similarly housed and received water only. On PND 75, without any prior training, periadolescent alcohol-drinking and periadolescent alcohol-naïve rats were placed in standard two-lever (15% EtOH and water) chambers to examine acquisition of EtOH self-administration with a fixed ratio (FR) 1 schedule of reinforcement. After the acquisition phase and after stable responding was established on an FR5 for EtOH and FR1 for water, P rats underwent extinction training for both EtOH and water rewards. After extinction training and a 2 week home cage period, rats were returned to the operant chambers in the absence of reward for seven consecutive sessions (Pavlovian spontaneous recovery). After this testing period, animals were maintained in their home cage for a week before being returned to the operant chambers and allowed to respond for EtOH and water (reacquisition). Compared with periadolescent alcohol-naïve rats, periadolescent alcohol-drinking rats acquired EtOH responding sooner (i.e., in the first acquisition session), displayed a greater resistance to extinguish EtOH responding (i.e., higher levels of responding in sessions 4-6), had higher responding for more sessions on the EtOH lever in the absence of reward after a prolonged home cage rest period, and had a more prolonged elevated level of EtOH responding during reacquisition (four sessions versus one session). Overall, the results suggest that periadolescent Et

  4. Differences in Methylphenidate Dose Response between Periadolescent and Adult Rats in the Familiar Arena-Novel Alcove TaskS⃞

    PubMed Central

    Zarcone, Troy J.; Davis, Paul F.; Ozias, Marlies K.; Fowler, Stephen C.

    2011-01-01

    Methylphenidate is a psychostimulant widely used in the treatment of attention deficit hyperactivity disorder. In this study, the effects of two nonstereotypy-inducing doses of methylphenidate (2.5 and 5.0 mg/kg s.c.) were examined in periadolescent [postnatal days (P) 35 and 42] and young adult (P70), male Long-Evans rats using a three-period locomotor activity paradigm that affords inferences about exploration, habituation, and attention to a novel stimulus (an “alcove”) in a familiar environment in a single test session. In the first test period, P35 and P42 rats were more active than P70 rats, and methylphenidate increased locomotion in a dose-related manner. The introduction of a novel spatial stimulus in the third test period revealed a significant interaction of dose and age such that P70 rats exhibited dose-related increases in distance traveled, but P35 rats did not. Furthermore, methylphenidate dose-relatedly disrupted the rats' tendency to spend increasing amounts of time in the alcove across the test period at P70 but not at P35. Brain and serum methylphenidate concentrations were significantly lower at P35 than at P70, with intermediate levels at P42. Developmental differences in dopaminergic neurochemistry were also observed, including increased dopamine content in the caudate-putamen, nucleus accumbens, and frontal cortex and decreased densities of D1-like receptors in the frontal cortex in P70 than in P42 rats. These results raise the possibility that children and adults may respond differently when treated with this drug, particularly in situations involving response to novelty and that these effects involve developmental differences in pharmacokinetics and dopaminergic neurochemistry. PMID:21205916

  5. Early Developmental Low-Dose Methylmercury Exposure Alters Learning and Memory in Periadolescent but Not Young Adult Rats.

    PubMed

    Albores-Garcia, Damaris; Acosta-Saavedra, Leonor C; Hernandez, Alberto J; Loera, Miriam J; Calderón-Aranda, Emma S

    2016-01-01

    Few studies have assessed the effects of developmental methylmercury (MeHg) exposure on learning and memory at different ages. The possibility of the amelioration or worsening of the effects has not been sufficiently investigated. This study aimed to assess whether low-dose MeHg exposure in utero and during suckling induces differential disturbances in learning and memory of periadolescent and young adult rats. Four experimental groups of pregnant Sprague-Dawley rats were orally exposed to MeHg or vehicle from gestational day 5 to weaning: (1) control (vehicle), (2) 250 μg/kg/day MeHg, (3) 500 μg/kg/day MeHg, and (4) vehicle, and treated on the test day with MK-801 (0.15 mg/kg i.p.), an antagonist of the N-methyl D-aspartate receptor. The effects were evaluated in male offspring through the open field test, object recognition test, Morris water maze, and conditioned taste aversion. For each test and stage assessed, different groups of animals were used. MeHg exposure, in a dose-dependent manner, disrupted exploratory behaviour, recognition memory, spatial learning, and acquisition of aversive memories in periadolescent rats, but alterations were not observed in littermates tested in young adulthood. These results suggest that developmental low-dose exposure to MeHg induces age-dependent detrimental effects. The relevance of decreasing exposure to MeHg in humans remains to be determined.

  6. Early Developmental Low-Dose Methylmercury Exposure Alters Learning and Memory in Periadolescent but Not Young Adult Rats

    PubMed Central

    Albores-Garcia, Damaris; Hernandez, Alberto J.; Loera, Miriam J.

    2016-01-01

    Few studies have assessed the effects of developmental methylmercury (MeHg) exposure on learning and memory at different ages. The possibility of the amelioration or worsening of the effects has not been sufficiently investigated. This study aimed to assess whether low-dose MeHg exposure in utero and during suckling induces differential disturbances in learning and memory of periadolescent and young adult rats. Four experimental groups of pregnant Sprague-Dawley rats were orally exposed to MeHg or vehicle from gestational day 5 to weaning: (1) control (vehicle), (2) 250 μg/kg/day MeHg, (3) 500 μg/kg/day MeHg, and (4) vehicle, and treated on the test day with MK-801 (0.15 mg/kg i.p.), an antagonist of the N-methyl D-aspartate receptor. The effects were evaluated in male offspring through the open field test, object recognition test, Morris water maze, and conditioned taste aversion. For each test and stage assessed, different groups of animals were used. MeHg exposure, in a dose-dependent manner, disrupted exploratory behaviour, recognition memory, spatial learning, and acquisition of aversive memories in periadolescent rats, but alterations were not observed in littermates tested in young adulthood. These results suggest that developmental low-dose exposure to MeHg induces age-dependent detrimental effects. The relevance of decreasing exposure to MeHg in humans remains to be determined. PMID:26885512

  7. Exposure to methylphenidate during peri-adolescence affects endocrine functioning and sexual behavior in female Long-Evans rats.

    PubMed

    Guarraci, Fay A; Holifield, Caroline; Morales-Valenzuela, Jessica; Greene, Kasera; Brown, Jeanette; Lopez, Rebecca; Crandall, Christina; Gibbs, Nicole; Vela, Rebekah; Delgado, Melissa Y; Frohardt, Russell J

    2016-03-01

    The present study was designed to test the effects of methylphenidate (MPH) exposure on the maturation of endocrine functioning and sexual behavior. Female rat pups received either MPH (2.0mg/kg, i.p.) or saline twice daily between postnatal days 20-35. This period of exposure represents the time just prior to puberty as well as puberty onset. Approximately five weeks after the last injection of MPH or saline, female subjects were hormone-primed and tested during their first sexual experience. Subjects were given the choice to interact with a sexually active male or a sexually receptive female rat (i.e., the partner-preference test). The partner-preference paradigm allows us to assess multiple aspects of female sexual behavior. MPH exposure during peri-adolescence delayed puberty and, when mated for the first time, affected sexual behavior (e.g., increased time spent with the male stimulus and decreased the likelihood of leaving after mounts) during the test of partner preference. When monitoring estrous cyclicity, female subjects treated with MPH during peri-adolescence frequently experienced irregular estrous cycles. The results of the present study suggest that chronic exposure to a therapeutic dose of MPH around the onset of puberty alters long-term endocrine functioning, but with hormone priming, increases sensitivity to sexual stimuli.

  8. Maternal deprivation and early handling affect density of calcium binding protein-containing neurons in selected brain regions and emotional behavior in periadolescent rats.

    PubMed

    Giachino, C; Canalia, N; Capone, F; Fasolo, A; Alleva, E; Riva, M A; Cirulli, F; Peretto, P

    2007-03-16

    Adverse early life experiences can induce neurochemical changes that may underlie modifications in hypothalamic-pituitary-adrenal axis responsiveness, emotionality and cognition. Here, we investigated the expression of the calcium binding proteins (CBPs) calretinin, calbindin and parvalbumin, which identify subpopulations of GABAergic neurons and serve important functional roles by buffering intracellular calcium levels, following brief (early handling) and long (maternal deprivation) periods of maternal separation, as compared with non-handled controls. CBP-expressing neurons were analyzed in brain regions related to stress and anxiety. Emotionality was assessed in parallel using the social interaction test. Analyses were carried out at periadolescence, an important phase for the development of brain areas involved in stress responses. Our results indicate that density of CBP-immunoreactive neurons decreases in the paraventricular region of deprived rats but increases in the hippocampus and lateral amygdala of both early-handled and deprived rats when compared with controls. Emotionality is reduced in both early-handled and deprived animals. In conclusion, early handling and deprivation led to neurochemical and behavioral changes linked to stress-sensitive brain regions. These data suggest that the effects of early experiences on CBP containing neurons might contribute to the functional changes of neuronal circuits involved in emotional response.

  9. Neural and behavioural changes in male periadolescent mice after prolonged nicotine-MDMA treatment.

    PubMed

    Adeniyi, Philip A; Ishola, Azeez O; Laoye, Babafemi J; Olatunji, Babawale P; Bankole, Oluwamolakun O; Shallie, Philemon D; Ogundele, Olalekan M

    2016-02-01

    The interaction between MDMA and Nicotine affects multiple brain centres and neurotransmitter systems (serotonin, dopamine and glutamate) involved in motor coordination and cognition. In this study, we have elucidated the effect of prolonged (10 days) MDMA, Nicotine and a combined Nicotine-MDMA treatment on motor-cognitive neural functions. In addition, we have shown the correlation between the observed behavioural change and neural structural changes induced by these treatments in BALB/c mice. We observed that MDMA (2 mg/Kg body weight; subcutaneous) induced a decline in motor function, while Nicotine (2 mg/Kg body weight; subcutaneous) improved motor function in male periadolescent mice. In combined treatment, Nicotine reduced the motor function decline observed in MDMA treatment, thus no significant change in motor function for the combined treatment versus the control. Nicotine or MDMA treatment reduced memory function and altered hippocampal structure. Similarly, a combined Nicotine-MDMA treatment reduced memory function when compared with the control. Ultimately, the metabolic and structural changes in these neural systems were seen to vary for the various forms of treatment. It is noteworthy to mention that a combined treatment increased the rate of lipid peroxidation in brain tissue.

  10. Modeling binge-like ethanol drinking by peri-adolescent and adult P rats

    PubMed Central

    Bell, Richard L.; Rodd, Zachary A.; Smith, Rebecca J.; Toalston, Jamie E.; Franklin, Kelle M.; McBride, William J.

    2011-01-01

    Alcohol binge-drinking, especially among adolescents and young adults, is a serious public health concern. The present study examined ethanol binge-like drinking by peri-adolescent [postnatal days (PNDs 30—72)] and adult (PNDs 90—132) alcohol-preferring (P) rats with a drinking-in-the-dark—multiple-scheduled-acces (DID-MSA) procedure used by our laboratory. Male and female P rats were provided concurrent access to 15% and 30% ethanol for three 1-hr sessions across the dark cycle 5 days/week. For the 1st week, adolescent and adult female P rats consumed 3.4 and 1.6 g/kg of ethanol, respectively, during the 1st hr of access, whereas for male rats the values were 3.5 and 1.1 g/kg of ethanol, respectively. Adult intakes increased to ~2.0 g/kg/hr and adolescent intakes decreased to ~2.5 g/kg/hr across the 6 weeks of ethanol access. The daily ethanol intake of adult DID-MSA rats approximated or modestly exceeded that seen in continuous access (CA) rats or the selection criterion for P rats (≥ 5g/kg/day). However, in general, the daily ethanol intake of DID-MSA peri-adolescent rats significantly exceeded that of their CA counterparts. BELs were assessed at 15-min intervals across the 3rd hr of access during the 4th week. Ethanol intake was 1.7 g/kg vs. 2.7 g/kg and BELs were 57 mg% vs. 100 mg% at 15- and 60-min, respectively. Intoxication induced by DID-MSA in female P rats was assessed during the 1st vs. 4th week of ethanol access. Level of impairment did not differ between the 2 weeks (106 vs. 97 sec latency to fall, 120 sec criterion) and was significant (vs. naïve controls) only during the 4th week. Overall, these findings support the use of the DID-MSA procedure in rats, and underscore the presence of age- and sex-dependent effects mediating ethanol binge-like drinking in P rats. PMID:21824488

  11. Effects of different concentrations of sugarcane alcohol on food intake and nutritional status of male and female periadolescent rats.

    PubMed

    Gonçalves de Orange, Luciana; Bion, Francisca Martins; Rolim de Lima, Cybelle

    2009-03-01

    The present study evaluated the effects of food and alcohol intake on the nutritional and metabolic status of male and female periadolescent rats submitted to single (15%) and multiple (10%, 20%, 30%) concentrations of hydroalcoholic solutions of sugar-based alcohol associated with a feed mixture. Thirty-six periadolescent Wistar rats were used and randomly arranged into three groups: Group A (control; 0% ethanol; six males and six females), Group B (15% ethanol; six males and six females), and Group C (10%, 20%, and 30% ethanol; six males and six females). Food consumption, body weight, water intake (mL), ethanol intake (g/kg/day), ethanol preference in relation to water and different concentrations, and serum biochemical dosages (glucose, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein (HDL) cholesterol, very low-density lipoprotein fraction, triglycerides, cholesterol/HDL [CT/HDL], albumin) were analyzed. Males from Group C ingested more feed than females, which consumed reducing amounts throughout the weeks studied. Males also had heavier body weight, which increased throughout the experimental period. The animals ingested more water (females ingested more than males) in the first experimental week. Group C had a higher ethanol intake and greater preference for ethanol over water in both genders than Group B, which decreased over the subsequent weeks. Serum glucose was lower in Group A, whereas the CT/HDL ratio was lower in Group C. These findings allow the conclusion that nutritional and metabolic impact resulting from alcohol intake is different between genders and between the different forms in which the drug is offered. It is important to warn the population about the concentrations of alcohol intake, which may influence the growth and development of adolescents, thereby compromising their quality of life.

  12. High-fructose diet during periadolescent development increases depressive-like behavior and remodels the hypothalamic transcriptome in male rats.

    PubMed

    Harrell, Constance S; Burgado, Jillybeth; Kelly, Sean D; Johnson, Zachary P; Neigh, Gretchen N

    2015-12-01

    Fructose consumption, which promotes insulin resistance, hypertension, and dyslipidemia, has increased by over 25% since the 1970s. In addition to metabolic dysregulation, fructose ingestion stimulates the hypothalamic-pituitary-adrenal (HPA) axis leading to elevations in glucocorticoids. Adolescents are the greatest consumers of fructose, and adolescence is a critical period for maturation of the HPA axis. Repeated consumption of high levels of fructose during adolescence has the potential to promote long-term dysregulation of the stress response. Therefore, we determined the extent to which consumption of a diet high in fructose affected behavior, serum corticosterone, and hypothalamic gene expression using a whole-transcriptomics approach. In addition, we examined the potential of a high-fructose diet to interact with exposure to chronic adolescent stress. Male Wistar rats fed the periadolescent high-fructose diet showed increased anxiety-like behavior in the elevated plus maze and depressive-like behavior in the forced swim test in adulthood, irrespective of stress history. Periadolescent fructose-fed rats also exhibited elevated basal corticosterone concentrations relative to their chow-fed peers. These behavioral and hormonal responses to the high-fructose diet did not occur in rats fed fructose during adulthood only. Finally, rats fed the high-fructose diet throughout development underwent marked hypothalamic transcript expression remodeling, with 966 genes (5.6%) significantly altered and a pronounced enrichment of significantly altered transcripts in several pathways relating to regulation of the HPA axis. Collectively, the data presented herein indicate that diet, specifically one high in fructose, has the potential to alter behavior, HPA axis function, and the hypothalamic transcriptome in male rats.

  13. High-fructose diet during periadolescent development increases depressive-like behavior and remodels the hypothalamic transcriptome in male rats

    PubMed Central

    Harrell, Constance S.; Burgado, Jillybeth; Kelly, Sean D.; Johnson, Zachary P.; Neigh, Gretchen N.

    2015-01-01

    Fructose consumption, which promotes insulin resistance, hypertension, and dyslipidemia, has increased by over 25% since the 1970s. In addition to metabolic dysregulation, fructose ingestion stimulates the hypothalamic-pituitary-adrenal (HPA) axis leading to elevations in glucocorticoids. Adolescents are the greatest consumers of fructose, and adolescence is a critical period for maturation of the HPA axis. Repeated consumption of high levels of fructose during adolescence has the potential to promote long-term dysregulation of the stress response. Therefore, we determined the extent to which consumption of a diet high in fructose affected behavior, serum corticosterone, and hypothalamic gene expression using a whole-transcriptomics approach. In addition, we examined the potential of a high-fructose diet to interact with exposure to chronic adolescent stress. Male Wistar rats fed the periadolescent high-fructose diet showed increased anxiety-like behavior in the elevated plus maze and depressive-like behavior in the forced swim test in adulthood, irrespective of stress history. Periadolescent fructose-fed rats also exhibited elevated basal corticosterone concentrations relative to their chow-fed peers. These behavioral and hormonal responses to the high-fructose diet did not occur in rats fed fructose during adulthood only. Finally, rats fed the high-fructose diet throughout development underwent marked hypothalamic transcript expression remodeling, with 966 genes (5.6%) significantly altered and a pronounced enrichment of significantly altered transcripts in several pathways relating to regulation of the HPA axis. Collectively, the data presented herein indicate that diet, specifically one high in fructose, has the potential to alter behavior, HPA axis function, and the hypothalamic transcriptome in male rats. PMID:26356038

  14. Chronic periadolescent alcohol consumption produces persistent cognitive deficits in rhesus macaques

    PubMed Central

    Wright, M. Jerry; Taffe, Michael A.

    2014-01-01

    Background Although human alcoholics exhibit lasting cognitive deficits, it can be difficult to definitively rule out pre-alcohol performance differences. For example, individuals with a family history of alcoholism are at increased risk for alcoholism and are also behaviorally impaired. Animal models of controlled alcohol exposure permit balanced group assignment, thereby ruling out the effects of pre-existing differences. Methods Periadolescent male rhesus macaques (N=5) consumed alcohol during 200 drinking sessions (M-F) across a 10-month period (mean daily alcohol consumption: 1.38 g/kg/day). A control group (N=5) consumed a fruit-flavored vehicle during the same period. Spatial working memory, visual discrimination learning and retention and response time behavioral domains were assessed with subtests of the Monkey CANTAB (CAmbridge Neuropsychological Test Automated Battery). Results Spatial working memory performance was impaired in the alcohol group after 120 drinking sessions (6 mo) in a manner that depended on retention interval. The chronic alcohol animals were also impaired in retaining a visual discrimination over 24 hrs when assessed 6-8 weeks after cessation of alcohol drinking. Finally, the presentation of distractors in the response time task impaired the response time and accuracy of the chronic alcohol group more than controls after 6 months of alcohol cessation. Conclusions Chronic alcohol consumption over as little as 6 months produces cognitive deficits, with some domains still affected after acute (6-8 wks) and lasting (6 mo) discontinuation from drinking. Animals were matched on alcohol preference and behavioral performance prior to exposure, thus providing strong evidence for the causal role of chronic alcohol in these deficits. PMID:25018042

  15. Effects of periadolescent ethanol exposure on alcohol preference in two BALB substrains.

    PubMed

    Blizard, David A; Vandenbergh, David J; Jefferson, Akilah L; Chatlos, Cynthia D; Vogler, George P; McClearn, Gerald E

    2004-01-01

    Ethanol exposure during adolescence is a rite of passage in many societies, but only a subset of individuals exposed to ethanol becomes dependent on alcohol. To explore individual differences in response to ethanol exposure, we compared the effects of periadolescent ethanol exposure on alcohol drinking in an animal model. Male and female mice of two BALB substrains were exposed to ethanol in one of three forms--choice [water vs. 10% (volume/volume) ethanol], forced (10% ethanol in a single bottle), or gradual (single bottle exposure, starting with 0.5% ethanol and increasing at 2-day intervals to 10% ethanol)--from the 6th through the 12th week of age and administered two-bottle alcohol preference tests (10% ethanol vs. water) for 15 days immediately thereafter. All three forms of ethanol exposure increased alcohol preference in male and female BALB/cByJ mice, relative to findings for ethanol-naive control animals. Only gradual ethanol exposure produced an increase in alcohol preference in BALB/cJ mice. During extended alcohol preference testing (for a total of 39 days) of mice in the gradual ethanol exposure group, the higher alcohol preference of the gradual ethanol-exposed BALB/cByJ male mice persisted, but alcohol preference of control group female mice in this strain--formerly ethanol naive, but at this point having received 10% ethanol in the two-bottle paradigm for 15 days--rose to the level of alcohol preference of female mice in the gradual ethanol exposure group. This finding demonstrated that both adolescent and adult ethanol exposure stimulated alcohol preference in female mice of this strain. Across days of testing in adulthood, alcohol preference of the gradual ethanol-exposed BALB/cJ mice decreased, resulting in a lack of effect of gradual exposure to ethanol on alcohol preference in both male and female mice of this strain during the period of extended testing. These strain differences support a genetic basis for the effects of ethanol exposure on

  16. Refractory period after hyperventilation-induced asthma.

    PubMed

    Bar-Yishay, E; Ben-Dov, I; Godfrey, S

    1983-05-01

    Nine young asthmatic subjects undertook isocapnic hyperventilation while breathing air under different conditions. Each subject undertook 2 pairs of tests. Pair A consisted of 2 hyperventilation challenges performed while breathing cold (2.8 +/- 1.4 degrees C) dry (2.3 +/- 0.05 mg H2O/L) air. Pair B consisted of an initial warm (38.0 +/- 0.9 degrees C) saturated air challenge followed by a cold dry challenge. Tests were closely matched in terms of ventilation and respiratory heat loss in the cold dry tests. The subjects were rendered refractory by the first cold dry hyperventilation challenge, the fall in forced expiratory volume in one second (FEV1) after hyperventilation in the first test (delta FEV1 = 39 +/- 5%) being significantly greater than that after the second challenge of Pair A (delta FEV1 = 21 +/- 5%, p less than 0.005). In test Pair B, the warm humid hyperventilation challenge neither caused significant asthma (delta FEV1 6 +/- 3%) nor rendered the subjects refractory to the subsequent cold dry test (delta FEV1 38 +/- 4%). Because in a previous study it was shown that exercise while breathing warm humid air could induce a refractory period without itself causing asthma, we conclude that hyperventilation-induced asthma is not the same as exercise-induced asthma in most subjects.

  17. Laternal nicotine exposure increases nicotine preference in periadolescent male but not female C57B1/6J mice.

    PubMed

    Klein, Laura Cousino; Stine, Michele McClellan; Pfaff, Donald W; Vandenbergh, David J

    2003-02-01

    Maternal cigarette smoking is a risk factor for adolescent smoking. One possible explanation for increased smoking by human adolescents after maternal nicotine exposure is that exposure increases nicotine preference. However, it is difficult to separate the biological and social causes of smoking behavior in humans. This experiment examined the relationship between maternal nicotine exposure and nicotine preference in periadolescent offspring using a mouse model of oral nicotine consumption. Pregnant females were provided saccharin-flavored water containing 50 microg/ml nicotine (n = 4) or no nicotine (n = 5) from the ninth day of gestation through weaning on postnatal day (PD) 21. Offspring from these females were tested for nicotine preference during periadolescence (PDs 35-42) by providing access to both saccharin-only and nicotine solutions (50 microg/ml) 24 hr a day in the home cage in a two-bottle choice test. Male mice exposed maternally to nicotine (n = 9) exhibited an increased nicotine preference in adolescence compared to non-nicotine exposed controls (n = 12). Maternal nicotine exposure did not alter nicotine preference by periadolescent female mice. Nicotine consumption was confirmed by serum cotinine measurement. These data are consistent with human epidemiological reports that maternal nicotine exposure is associated with increased risk of cigarette smoking. Differential outcomes for males and females suggest that different processes underlie sex differences in nicotine consumption following maternal nicotine exposure.

  18. The reinforcing properties of ethanol are quantitatively enhanced in adulthood by peri-adolescent ethanol, but not saccharin, consumption in female alcohol-preferring (P) rats.

    PubMed

    Toalston, Jamie E; Deehan, Gerald A; Hauser, Sheketha R; Engleman, Eric A; Bell, Richard L; Murphy, James M; McBride, William J; Rodd, Zachary A

    2015-08-01

    Alcohol drinking during adolescence is associated in adulthood with heavier alcohol drinking and an increased rate of alcohol dependence. Past research in our laboratory has indicated that peri-adolescent ethanol consumption can enhance the acquisition and reduce the rate of extinction of ethanol self-administration in adulthood. Caveats of the past research include reinforcer specificity, increased oral consumption during peri-adolescence, and a lack of quantitative assessment of the reinforcing properties of ethanol. The current experiments were designed to determine the effects of peri-adolescent ethanol or saccharin drinking on acquisition and extinction of oral ethanol self-administration and ethanol seeking, and to quantitatively assess the reinforcing properties of ethanol (progressive ratio). Ethanol or saccharin access by alcohol-preferring (P) rats occurred during postnatal day (PND) 30-60. Animals began operant self-administration of ethanol or saccharin after PND 85. After 10 weeks of daily operant self-administration, rats were tested in a progressive ratio paradigm. Two weeks later, self-administration was extinguished in all rats. Peri-adolescent ethanol consumption specifically enhanced the acquisition of ethanol self-administration, reduced the rate of extinction for ethanol self-administration, and quantitatively increased the reinforcing properties of ethanol during adulthood. Peri-adolescent saccharin consumption was without effect. The data indicate that ethanol consumption during peri-adolescence results in neuroadaptations that may specifically enhance the reinforcing properties of ethanol during adulthood. This increase in the reinforcing properties of ethanol could be a part of biological sequelae that are the basis for the effects of adolescent alcohol consumption on the increase in the rate of alcoholism during adulthood.

  19. Behavioural and neuroendocrine effects of cannabinoids in critical developmental periods.

    PubMed

    Viveros, M P; Llorente, R; Moreno, E; Marco, E M

    2005-09-01

    The present article focuses on psychoneuroendocrine effects of cannabinoids in developing animals, with special emphasis on the perinatal, periweanling and periadolescent periods. We describe and discuss published data dealing with acute and long-term effects of exposure to cannabinoid agonists in such critical periods. Human studies have demonstrated that the consumption of marijuana by women during pregnancy affects the neurobehavioural development of their children. Investigations using animal models provide useful information for a better understanding of the long-lasting deleterious consequences of cannabis exposure during pregnancy and lactation. The increasing use of cannabis among adolescents and its associated public health problems have led to a parallel increase in basic research on appropriate animal models. Chronic administration of cannabinoid agonists during the periadolescent period causes persistent behavioural alterations in adult animals. Some of these alterations may be related to a possible increased risk of psychosis and other neuropsychiatric disorders in early onset cannabis users.

  20. Laser-induced periodic surface structuring of biopolymers

    NASA Astrophysics Data System (ADS)

    Pérez, Susana; Rebollar, Esther; Oujja, Mohamed; Martín, Margarita; Castillejo, Marta

    2013-03-01

    We report here on a systematic study about the formation of laser-induced periodic surface structures (LIPSS) on biopolymers. Self-standing films of the biopolymers chitosan, starch and the blend of chitosan with the synthetic polymer poly (vinyl pyrrolidone), PVP, were irradiated in air with linearly polarized laser beams at 193, 213 and 266 nm, with pulse durations in the range of 6-17 ns. The laser-induced periodic surface structures were topographically characterized by atomic force microscopy and the chemical modifications induced by laser irradiation were inspected via Raman spectroscopy. Formation of LIPSS parallel to the laser polarization direction, with periods similar to the laser wavelength, was observed at efficiently absorbed wavelengths in the case of the amorphous biopolymer chitosan and its blend with PVP, while formation of LIPSS is prevented in the crystalline starch biopolymer.

  1. Laser-induced periodic surface structures: Fingerprints of light localization

    NASA Astrophysics Data System (ADS)

    Skolski, J. Z. P.; Römer, G. R. B. E.; Obona, J. V.; Ocelik, V.; Huis in't Veld, A. J.; de Hosson, J. Th. M.

    2012-02-01

    The finite-difference time-domain (FDTD) method is used to study the inhomogeneous absorption of linearly polarized laser radiation below a rough surface. The results are first analyzed in the frequency domain and compared to the efficacy factor theory of Sipe and coworkers. Both approaches show that the absorbed energy shows a periodic nature, not only in the direction orthogonal to the laser polarization, but also in the direction parallel to it. It is shown that the periodicity is not always close to the laser wavelength for the perpendicular direction. In the parallel direction, the periodicity is about λ/Re(ñ), with ñ being the complex refractive index of the medium. The space-domain FDTD results show a periodicity in the inhomogeneous energy absorption similar to the periodicity of the low- and high-spatial-frequency laser-induced periodic surface structures depending on the material's excitation.

  2. Laser-induced transient grating setup with continuously tunable period

    SciTech Connect

    Vega-Flick, A.; Eliason, J. K.; Maznev, A. A.; Nelson, K. A.; Khanolkar, A.; Abi Ghanem, M.; Boechler, N.; Alvarado-Gil, J. J.

    2015-12-15

    We present a modification of the laser-induced transient grating setup enabling continuous tuning of the transient grating period. The fine control of the period is accomplished by varying the angle of the diffraction grating used to split excitation and probe beams. The setup has been tested by measuring dispersion of bulk and surface acoustic waves in both transmission and reflection geometries. The presented modification is fully compatible with optical heterodyne detection and can be easily implemented in any transient grating setup.

  3. Betamethasone-induced hypokalemic periodic paralysis in pregnancy.

    PubMed

    Teagarden, Corey M; Picardo, Carla W

    2011-02-01

    Acute hypokalemic periodic paralysis may be induced by betamethasone injections during pregnancy. A healthy 23-year-old gravid woman at 32 weeks of gestation with preterm premature rupture of membranes received two doses of 12-mg intramuscular betamethasone 24 hours apart to accelerate fetal lung maturation. She developed significant proximal muscle weakness within 16 hours after the initial dose. Her serum potassium was 1.6 mEq/L. Oral and parenteral potassium replacement restored her neuromuscular function over several days. She delivered by repeat cesarean at 34 weeks of gestation without complications for her or the neonate. Hypokalemic periodic paralysis, a rare cause of weakness, may be induced by betamethasone injections during pregnancy and is reversible with low-risk interventions.

  4. Superconductivity-induced phase-periodic transport in nanoscale structures

    NASA Astrophysics Data System (ADS)

    Leadbeater, M.; Lambert, C. J.

    1997-07-01

    We present numerical results for the phase-periodic conductance of an Andreev interferometer and predict the existence of a voltage-induced crossover from a zero-phase minimum to a zero-phase maximum. This contrasts with a recent analysis of Stoof and Nazarov and Volkov, Allsopp, and Lambert, which predicts a vanishing amplitude of oscillation at zero temperature and voltage, respectively, and demonstrates that such behavior is nonuniversal.

  5. Superconductivity-induced phase-periodic transport in nanoscale structures

    SciTech Connect

    Leadbeater, M.; Lambert, C.J.

    1997-07-01

    We present numerical results for the phase-periodic conductance of an Andreev interferometer and predict the existence of a voltage-induced crossover from a zero-phase minimum to a zero-phase maximum. This contrasts with a recent analysis of Stoof and Nazarov and Volkov, Allsopp, and Lambert, which predicts a vanishing amplitude of oscillation at zero temperature and voltage, respectively, and demonstrates that such behavior is nonuniversal. {copyright} {ital 1997} {ital The American Physical Society}

  6. Methylphenidate improves performance on the radial arm maze in periadolescent rats

    PubMed Central

    Dow-Edwards, Diana L.; Weedon, Jeremy C.; Hellmann, Esther

    2008-01-01

    Methylphenidate (Ritalin; MPD) is one of the most commonly prescribed drugs in childhood and adolescence and many clinical studies have documented its efficacy. Due to the limitations of conducting invasive research in humans, animal models can be beneficial for studying drug effects. However, few animal studies have demonstrated the effects of methylphenidate on cognitive processes. The objective of this study was to find a dose of methylphenidate that was effective in improving performance on a spatial working memory cognitive task when administered orally to periadolescent rats. Therefore, we dosed subjects with methylphenidate at 1 or 3 mg/kg/day via gastric intubation from postnatal day 22 to 59 and assessed the effects of the drug on performance on the radial arm maze each day. To enhance performance overall, a second experiment was conducted where the subjects were moderately food restricted (to 90% of the free-feeding weight). Results of Experiment 1 show that during the first week of testing only the 3mg/kg MPD-treated males showed improved performance (entries prior to repeated entry) when ad-lib fed and housed in pairs while the same dose significantly improved performance in both males and females under conditions of food-restriction and individual housing in Experiment 2. MPD also produced a pattern of increased errors and arms entered during the first week, especially in Experiment 2. MPD increased locomotor activity when tested at postnatal day 60 in both experiments. The data suggest that 3mg/kg oral methylphenidate improves performance on a spatial cognitive task only early in treatment in the rat. While males show improvement under conditions of both high and low motivation, females only show MPD effects when highly motivated. Hypothetically, methylphenidate may improve radial arm maze performance through increased attention and improved spatial working memory and/or alterations in locomotion, reactivity to novelty or anxiety. Regardless, the

  7. Laser-induced periodic surface structures, modeling, experiments, and applications

    NASA Astrophysics Data System (ADS)

    Römer, G. R. B. E.; Skolski, J. Z. P.; Oboňa, J. Vincenc; Ocelík, V.; de Hosson, J. T. M.; Huis in't Veld, A. J.

    2014-03-01

    Laser-induced periodic surface structures (LIPSSs) consist of regular wavy surface structures, or ripples, with amplitudes and periodicity in the sub-micrometer range. A summary of experimentally observed LIPSSs is presented, as well as our model explaining their possible origin. Linearly polarized continuous wave (cw) or pulsed laser light, at normal incidence, can produce LIPSSs with a periodicity close to the laser wavelength, and direction orthogonal to the polarization on the surface of the material. Ripples with a periodicity (much) smaller than the laser wavelength develop when applying laser pulses with ultra-short durations in the femtosecond and picosecond regime. The direction of these ripples is either parallel or orthogonal to the polarization direction. Finally, when applying numerous pulses, structures with periodicity larger than the laser wavelength can form, which are referred to as "grooves". The physical origin of LIPSSs is still under debate. The strong correlation of the ripple periodicity to the laser wavelength, suggests that their formation can be explained by an electromagnetic approach. Recent results from a numerical electromagnetic model, predicting the spatially modulated absorbed laser energy, are discussed. This model can explain the origin of several characteristics of LIPSSs. Finally, applications of LIPSSs will be discussed.

  8. Optimizing periodicity and polymodality in noise-induced genetic oscillators.

    PubMed

    Rué, Pau; Süel, Gürol M; Garcia-Ojalvo, Jordi

    2011-06-01

    Many cellular functions are based on the rhythmic organization of biological processes into self-repeating cascades of events. Some of these periodic processes, such as the cell cycles of several species, exhibit conspicuous irregularities in the form of period skippings, which lead to polymodal distributions of cycle lengths. A recently proposed mechanism that accounts for this quantized behavior is the stabilization of a Hopf-unstable state by molecular noise. Here we investigate the effect of varying noise in a model system, namely an excitable activator-repressor genetic circuit, that displays this noise-induced stabilization effect. Our results show that an optimal noise level enhances the regularity (coherence) of the cycles, in a form of coherence resonance. Similar noise levels also optimize the multimodal nature of the cycle lengths. Together, these results illustrate how molecular noise within a minimal gene regulatory motif confers robust generation of polymodal patterns of periodicity.

  9. Radiation-induced dural fibrosarcoma with unusually short latent period

    SciTech Connect

    Ghatak, N.R.; Aydin, F.; Leshner, R.T. Tulane Univ., New Orleans, LA )

    1993-05-01

    Although rare, the occurrence of radiation-induced intracranial neoplasms of various types is well known. Among these tumors, fibrosarcomas, especially in the region of seila turcica, seem to be the most common type. These tumors characteristically occur after a long latent period, usually several years, following radiation therapy. The authors now report a case of apparently radiation-induced fibrosarcoma with some unusual features in a 10-year-old boy who was treated with radiation for medulloblastoma. He received a total dose of 53.2 Gy radiation delivered at 1.8 per fraction with 6 MV acceleration using the standard craniospinal technique. An MRI at 15 months after the completion of radiotherapy showed a mass over the cerebral convexity, which increased two-fold in size within a period of 4 months. A well circumscribed tumor was removed from the fronto-parietal convexity. The tumor measured 5x4.5x1.5 cm and was attached to the dura with invasion of the overlying bone. Histologically, it displayed the characteristic features of a low-grade fibrosarcoma. The patient remains free of tumor 18 months after the surgery. This case emphasizes the potential risk for the development of a second neoplasm following therapeutic radiation and also documents, to the authors' knowledge, the shortest latent period reported so far between administration of radiotherapy and development of an intracranial tumor.

  10. Nanoscale Periodic Modulations on Sodium Chloride Induced by Surface Charges

    SciTech Connect

    Clark, Kendal W; Qin, Shengyong; Zhang, Xiaoguang; Li, An-Ping

    2012-01-01

    The sodium chloride surface is one of the most common platforms for the study of catalysts, thin film growth, and atmospheric aerosols. Here we report a nanoscale periodic modulation pattern on the surface of a cleaved NaCl single crystal, revealed by non-contact atomic force microscopy with a tuning fork sensor. The surface pattern shows two orthogonal domains, extending over the entire cleavage surface. The spatial modulations exhibit a characteristic period of 5.4 nm, along 110 crystallographic directions of the NaCl. The modulations are robust in vacuum, not affected by the tip-induced electric field or gentle annealing (<300 C); however, they are eliminated after exposure to water and an atomically flat surface can be recovered by subsequent thermal annealing after water exposure. A strong electrostatic charging is revealed on the cleavage surface which may facilitate the formation of the observed metastable surface reconstruction.

  11. Femtosecond laser-induced periodic surface structures on silica

    SciTech Connect

    Hoehm, S.; Rosenfeld, A.; Krueger, J.; Bonse, J.

    2012-07-01

    The formation of laser-induced periodic surface structures (LIPSS) on two different silica polymorphs (single-crystalline synthetic quartz and commercial fused silica glass) upon irradiation in air with multiple linearly polarized single- and double-fs-laser pulse sequences ({tau} = 150 fs pulse duration, {lambda} = 800 nm center wavelength, temporal pulse separation {Delta}t < 40 ps) is studied experimentally and theoretically. Two distinct types of fs-LIPSS [so-called low-spatial-frequency LIPSS (LSFL) and high-spatial-frequency LIPSS (HSFL)] with different spatial periods and orientations were identified. Their appearance was characterized with respect to the experimental parameters peak laser fluence and number of laser pulses per spot. Additionally, the 'dynamics' of the LIPSS formation was addressed in complementary double-fs-pulse experiments with varying delays, revealing a characteristic change of the LSFL periods. The experimental results are interpreted on the basis of a Sipe-Drude model considering the carrier dependence of the optical properties of fs-laser excited silica. This new approach provides an explanation of the LSFL orientation parallel to the laser beam polarisation in silica - as opposed to the behaviour of most other materials.

  12. Mud-induced periodic stratification in the hyperconcentrated Ems estuary

    NASA Astrophysics Data System (ADS)

    Becker, Marius; Maushake, Christian; Winter, Christian

    2017-04-01

    Feedback of stratification on the flow is widely acknowledged to play a significant role in estuarine sediment transport. Recently, attention was drawn to the influence of sediment-induced horizontal density gradients on the location of the estuarine turbidity zone and, in general, on subtidal dynamics in hyper-concentrated estuaries. By contrast to the increasing number of modelling studies, few experimental results were published regarding the actual vertical structure of the water column, or the intratidal dynamics of high concentration layers, such as fluid mud. In this study, we measured tidal variations of stratification due to suspended sediments in the center of the turbidity zone of the Ems estuary, North Sea. The suspended sediment concentration profile was controlled by strong vertical gradients, first, a lutocline on top of a mobile mud layer, and second, an interface that separated the mobile mud from a higher concentrated, stationary mud layer below (> 50 g/l). Entrainment of the mobile mud layer was observed at the beginning of the flood tide. Re-formation of the mobile mud layer occurred at an unexpectedly early stage during flood. This is interpreted to result from super-saturated conditions after entrainment. The exceptionally high concentration of suspended sediments was not sustained during stagnating flow, and the settling flux was increased, inducing a collapse of the vertical concentration profile. Subsequently, the flow was decoupled between the upper and the lower layer and separated by the lutocline approximately in the middle of the water column. Remarkably, the flow was flood directed in the upper layer, while velocities in the lower, mobile mud layer were ebb directed. The mobile mud layer remained unaffected by entrainment for a period of 4.5 h around high water and moved in ebb direction, with a peak velocity of 0.12 m/s. This ebb directed turbidity current is seen as the combined effect of the downstream concentration gradient and

  13. Coherence in ultrafast laser-induced periodic surface structures

    NASA Astrophysics Data System (ADS)

    Zhang, Hao; Colombier, Jean-Philippe; Li, Chen; Faure, Nicolas; Cheng, Guanghua; Stoian, Razvan

    2015-11-01

    Ultrafast laser irradiation can trigger anisotropically structured nanoscaled gratinglike arrangements of matter, the laser-induced periodic surface structures (LIPSSs). We demonstrate here that the formation of LIPSS is intrinsically related to the coherence of the laser field. Employing several test materials that allow large optical excursions, we observe the effect of randomizing spatial phase in generating finite domains of ripples. Using three-dimensional finite-difference time-domain methods, we evaluate energy deposition patterns below a material's rough surface and show that modulated pattern, i.e., a spatially ordered electromagnetic solution, results from the coherent superposition of waves. By separating the field scattered from a surface rough topography from the total field, the inhomogeneous energy absorption problem is reduced to a simple interference equation. We further distinguish the contribution of the scattered near field and scattered far field on various types of inhomogeneous energy absorption features. It is found that the inhomogeneous energy absorption which could trigger the low-spatial-frequency LIPSSs (LSFLs) and high-spatial-frequency LIPSSs (HSFLs) of periodicity Λ >λ /Re(n ˜) are due to coherent superposition between the scattered far field (propagation) and the refracted field, while HSFLs of Λ <λ /Re(n ˜) are triggered by coherent superposition between the scattered near field (evanescent) and the refracted field. This is a general scenario that involves a topography-induced scattering phenomenon and stationary evanescent fields, being applied to two model case materials that exhibit large optical excursions upon excitation (W, Si) and nonplasmonic to plasmonic transitions. We indicate the occurrence of a general light interference phenomenon that does not necessarily involve wavelike surface plasmonic excitation. Finally, we discuss the role of interference field and scattered field on the enhancement of LIPSSs by

  14. Polarization-independent mechanically induced long-period fiber gratings

    NASA Astrophysics Data System (ADS)

    Block, Ueyn L.; Ozcan, Aydogan; Digonnet, Michel J. F.; Fejer, Martin M.

    2002-05-01

    We have developed long-period fiber gratings (LPFGs) utilizing the photoelastic effect and have demonstrated polarization-independent operation. The LPFG is made by pressing a standard, jacketed single-mode fiber between a flat plate and a plate with grooves mechanically machined with a suitable period. The grating's transmission spectrum is easily tuned by adjusting pressure, grating tilt, and length. Furthermore, the grating can be completely erased by removing the pressure from the fiber. Grating attenuation greater than 25 dB has been demonstrated with a notch-location polarization dependence of +-4 nm. In this paper we report drastic reduction in this polarization dependence by two different approaches. Passing through the grating a second time after reflecting off a Faraday rotator mirror was successful; this method may be used with other types of LPFGs. The second approach utilizes our mechanical grating's ability to be double-passed with two fibers side-by-side. Between passes, a fiber-loop half-wave plate aligned at 45 degrees to the plane of the grooved plate swaps power between x- and y-polarization states. The resulting output's measured polarization dependence was smaller than +/- 0.2 nm. Further improvement is expected through careful tuning of the wave plate. We also report a computer model of the filter spectrum and its polarization dependence, which takes into account non-uniform index perturbation, lossy cladding modes, cladding index perturbation, as well as the polarization dependence of the photoelastic effect, characteristics not usually present in UV-induced LPFGs. The model generates transmission spectra that agree quite well with experimental results.

  15. Periodization

    PubMed Central

    Lorenz, Daniel S.; Reiman, Michael P.; Walker, John C.

    2010-01-01

    Background: Clinicians are constantly faced with the challenge of designing training programs for injured and noninjured athletes that maximize healing and optimize performance. Periodization is a concept of systematic progression—that is, resistance training programs that follow predictable patterns of change in training variables. The strength training literature is abundant with studies comparing periodization schemes on uninjured, trained, and untrained athletes. The rehabilitation literature, however, is scarce with information about how to optimally design resistance training programs based on periodization principles for injured athletes. The purpose of this review is to discuss relevant training variables and methods of periodization, as well as periodization program outcomes. A secondary purpose is to provide an anecdotal framework regarding implementation of periodization principles into rehabilitation programs. Evidence Acquisition: A Medline search from 1979 to 2009 was implemented with the keywords periodization, strength training, rehabilitation, endurance, power, hypertrophy, and resistance training with the Boolean term AND in all possible combinations in the English language. Each author also undertook independent hand searching of article references used in this review. Results: Based on the studies researched, periodized strength training regimens demonstrate improved outcomes as compared to nonperiodized programs. Conclusions: Despite the evidence in the strength training literature supporting periodization programs, there is a considerable lack of data in the rehabilitation literature about program design and successful implementation of periodization into rehabilitation programs. PMID:23015982

  16. Periadolescent ethanol vapor exposure produces reductions in hippocampal volume that are correlated with deficits in prepulse inhibition of the startle

    PubMed Central

    Ehlers, Cindy L.; Oguz, Ipek; Budin, Francois; Wills, Derek N.; Crews, Fulton T.

    2013-01-01

    BACKGROUND Epidemiological studies suggest that excessive alcohol consumption is prevalent among adolescents and may have lasting neurobehavioral consequences. The use of animal models allows for the separation of the effects of adolescent ethanol exposure from genetic background and other environmental insults. In the present study the effects of moderate ethanol vapor exposure, during adolescence, on structural diffusion tensor imaging (DTI) and behavioral measures were evaluated in adulthood. METHODS A total of 53 Wistar rats were received at postnatal day (PD) 21, and were randomly assigned to ethanol vapor (14 hrs on/10 hrs off/day) or air exposure for 35 days from PD 23-PD 58 (average blood ethanol concentration (BEC): 169 mg%). Animals were received in two groups that were subsequently sacrificed at two time points following withdrawal from ethanol vapor: (1) at 72 days of age, 2 weeks following withdrawal or (2) at day 128, 10 weeks following withdrawal. In the second group, behavior in the light/dark box and prepulse inhibition of the startle (PPI) were also evaluated. Fifteen animals in each group were scanned, post mortem, for structural DTI. RESULTS There were no significant differences in body weight between ethanol and control animals. Volumetric data, demonstrated that total brain, hippocampal, corpus callosum but not ventricular volume was significantly larger in the 128 day sacrificed animals as compared to the 72 day animals. The hippocampus was smaller and the ventricles larger at 128 days as compared to 72 days, in the ethanol exposed animals, leading to a significant group × time effect. Ethanol exposed animals sacrificed at 128 days also had diminished PPI and more rears in the light box that were significantly correlated with hippocampal size. CONCLUSIONS These studies demonstrate that DTI volumetric measures of hippocampus are significantly impacted by age and periadolescent ethanol exposure and withdrawal in Wistar rats. PMID:23578102

  17. Unidirectional Invisibility Induced by PT-Symmetric Periodic Structures

    SciTech Connect

    Lin Zin; Ramezani, Hamidreza; Kottos, Tsampikos; Eichelkraut, Toni; Christodoulides, Demetrios N.; Cao Hui

    2011-05-27

    Parity-time (PT) symmetric periodic structures, near the spontaneous PT-symmetry breaking point, can act as unidirectional invisible media. In this regime, the reflection from one end is diminished while it is enhanced from the other. Furthermore, the transmission coefficient and phase are indistinguishable from those expected in the absence of a grating. The phenomenon is robust even in the presence of Kerr nonlinearities, and it can also effectively suppress optical bistabilities.

  18. Unidirectional invisibility induced by PT-symmetric periodic structures.

    PubMed

    Lin, Zin; Ramezani, Hamidreza; Eichelkraut, Toni; Kottos, Tsampikos; Cao, Hui; Christodoulides, Demetrios N

    2011-05-27

    Parity-time (PT) symmetric periodic structures, near the spontaneous PT-symmetry breaking point, can act as unidirectional invisible media. In this regime, the reflection from one end is diminished while it is enhanced from the other. Furthermore, the transmission coefficient and phase are indistinguishable from those expected in the absence of a grating. The phenomenon is robust even in the presence of Kerr nonlinearities, and it can also effectively suppress optical bistabilities. © 2011 American Physical Society

  19. Temperature-Induced Increase of Spin Spiral Periods

    NASA Astrophysics Data System (ADS)

    Finco, Aurore; Rózsa, Levente; Hsu, Pin-Jui; Kubetzka, André; Vedmedenko, Elena; von Bergmann, Kirsten; Wiesendanger, Roland

    2017-07-01

    Spin-polarized scanning tunneling microscopy investigations reveal a significant increase of the magnetic period of spin spirals in three-atomic-layer-thick Fe films on Ir(111), from about 4 nm at 8 K to about 65 nm at room temperature. We attribute this considerable influence of temperature on the magnetic length scale of noncollinear spin states to different exchange interaction coefficients in the different Fe layers. We thus propose a classical spin model that reproduces the experimental observations and in which the crucial feature is the presence of magnetically coupled atomic layers with different interaction strengths. This model might also apply for many other systems, especially magnetic multilayers.

  20. Period doubling induced by thermal noise amplification in genetic circuits

    PubMed Central

    Ruocco, G.; Fratalocchi, A.

    2014-01-01

    Rhythms of life are dictated by oscillations, which take place in a wide rage of biological scales. In bacteria, for example, oscillations have been proven to control many fundamental processes, ranging from gene expression to cell divisions. In genetic circuits, oscillations originate from elemental block such as autorepressors and toggle switches, which produce robust and noise-free cycles with well defined frequency. In some circumstances, the oscillation period of biological functions may double, thus generating bistable behaviors whose ultimate origin is at the basis of intense investigations. Motivated by brain studies, we here study an “elemental” genetic circuit, where a simple nonlinear process interacts with a noisy environment. In the proposed system, nonlinearity naturally arises from the mechanism of cooperative stability, which regulates the concentration of a protein produced during a transcription process. In this elemental model, bistability results from the coherent amplification of environmental fluctuations due to a stochastic resonance of nonlinear origin. This suggests that the period doubling observed in many biological functions might result from the intrinsic interplay between nonlinearity and thermal noise. PMID:25404210

  1. Period doubling induced by thermal noise amplification in genetic circuits.

    PubMed

    Ruocco, G; Fratalocchi, A

    2014-11-18

    Rhythms of life are dictated by oscillations, which take place in a wide rage of biological scales. In bacteria, for example, oscillations have been proven to control many fundamental processes, ranging from gene expression to cell divisions. In genetic circuits, oscillations originate from elemental block such as autorepressors and toggle switches, which produce robust and noise-free cycles with well defined frequency. In some circumstances, the oscillation period of biological functions may double, thus generating bistable behaviors whose ultimate origin is at the basis of intense investigations. Motivated by brain studies, we here study an "elemental" genetic circuit, where a simple nonlinear process interacts with a noisy environment. In the proposed system, nonlinearity naturally arises from the mechanism of cooperative stability, which regulates the concentration of a protein produced during a transcription process. In this elemental model, bistability results from the coherent amplification of environmental fluctuations due to a stochastic resonance of nonlinear origin. This suggests that the period doubling observed in many biological functions might result from the intrinsic interplay between nonlinearity and thermal noise.

  2. Period doubling induced by thermal noise amplification in genetic circuits

    NASA Astrophysics Data System (ADS)

    Ruocco, G.; Fratalocchi, A.

    2014-11-01

    Rhythms of life are dictated by oscillations, which take place in a wide rage of biological scales. In bacteria, for example, oscillations have been proven to control many fundamental processes, ranging from gene expression to cell divisions. In genetic circuits, oscillations originate from elemental block such as autorepressors and toggle switches, which produce robust and noise-free cycles with well defined frequency. In some circumstances, the oscillation period of biological functions may double, thus generating bistable behaviors whose ultimate origin is at the basis of intense investigations. Motivated by brain studies, we here study an ``elemental'' genetic circuit, where a simple nonlinear process interacts with a noisy environment. In the proposed system, nonlinearity naturally arises from the mechanism of cooperative stability, which regulates the concentration of a protein produced during a transcription process. In this elemental model, bistability results from the coherent amplification of environmental fluctuations due to a stochastic resonance of nonlinear origin. This suggests that the period doubling observed in many biological functions might result from the intrinsic interplay between nonlinearity and thermal noise.

  3. Inducing nonclassical lasing via periodic drivings in circuit quantum electrodynamics.

    PubMed

    Navarrete-Benlloch, Carlos; García-Ripoll, Juan José; Porras, Diego

    2014-11-07

    We show how a pair of superconducting qubits coupled to a microwave cavity mode can be used to engineer a single-atom laser that emits light into a nonclassical state. Our scheme relies on the dressing of the qubit-field coupling by periodic modulations of the qubit energy. In the dressed basis, the radiative decay of the first qubit becomes an effective incoherent pumping mechanism that injects energy into the system, hence turning dissipation to our advantage. A second, auxiliary qubit is used to shape the decay within the cavity, in such a way that lasing occurs in a squeezed basis of the cavity mode. We characterize the system both by mean-field theory and exact calculations. Our work may find applications in the generation of squeezing and entanglement in circuit QED, as well as in the study of dissipative few- and many-body phase transitions.

  4. Permanence induced by life-cycle resonances: the periodical cicada problem.

    PubMed

    Kon, Ryusuke

    2012-01-01

    Periodical cicadas are known for their unusually long life cycle for insects and their prime periodicity of either 13 or 17 years. One of the explanations for the prime periodicity is that the prime periods are selected to prevent cicadas from resonating with predators with submultiple periods. This paper considers this hypothesis by investigating a population model for periodical predator and prey. The study shows that if the periods of the two periodical species are not coprime, then the predator cannot resist the invasion of the prey. On the other hand, if the periods are coprime, then the predator can resist the invasion of the prey. It is also shown that if the periods are not coprime, then the life-cycle resonance can induce a permanent system, in which no cohorts are missing in both populations. On the other hand, if the periods are coprime, then the system cannot be permanent.

  5. Photon localization in disorder-induced periodic multilayers

    NASA Astrophysics Data System (ADS)

    van Tiggelen, Bart A.; Tip, Adriaan

    1991-08-01

    We studied the influence of randomness on a periodic dielectric 1D stratified system. Numerical simulations are performed, and are compared to theoretical predictions. Non-analytic behaviour is found at the band edges. The anomalies that can arise in the middle of a band turn out to be far more pronounced than the ones in the Anderson-model. Nous avons examiné l'influence du désordre sur un système et stratifié et diélectrique, à une dimension. Le système est d'origine périodique. Des simulations numériques ont été effectuées et devraient être confrontées à des prédictions théoriques. L'exposant de Lyapunov est non analytique aux bords du spectre. Nous avons constaté que les anomalies qui pourraient se trouver au centre des bandes sont beaucoup plus nettes que celles dans le modèle d'Anderson.

  6. Periadolescent ethanol vapor exposure persistently reduces measures of hippocampal neurogenesis that are associated with behavioral outcomes in adulthood.

    PubMed

    Ehlers, C L; Liu, W; Wills, D N; Crews, F T

    2013-08-06

    . The reduction seen in DCX labeled in cell counts was significantly correlated with hypoactivity at 24h after withdrawal as well as less anxiety-like and/or more "disinhibitory" behavior in the open field conflict test at 2 and 8 weeks following termination of vapor exposure. These studies demonstrate that behavioral measures of disinhibitory behavior correlated with decreases in neurogenesis are all significantly and persistently impacted by periadolescent ethanol exposure and withdrawal in Wistar rats.

  7. Lorazepam-induced effects on silent period and corticomotor excitability.

    PubMed

    Kimiskidis, V K; Papagiannopoulos, S; Kazis, D A; Sotirakoglou, K; Vasiliadis, G; Zara, F; Kazis, A; Mills, K R

    2006-09-01

    TMS studies on the CNS effects of benzodiazepines have provided contradictory results. The objective of this study is to describe the effects of lorazepam on silent period (SP) and corticomotor excitability. Twelve healthy male subjects (median age 35 years) were studied at baseline, following i.v. lorazepam administration and after reversal of the benzodiazepine effects with i.v. flumazenil. Lorazepam was given at a low-dose in one subject (0.0225 mg/kg bolus + 2 microg/kg/h infusion) and at a high-dose (0.045 mg/kg bolus + 2.6 microg/kg/h infusion) in the rest. Threshold (Thr) was measured at 1% steps. SPs were investigated with two complementary methods. First, SPs were elicited using a wide range of stimulus intensities (SIs) (from 5 to 100% maximum SI at 5% increments). At each SI, four SPs were obtained and the average value of SP duration was used to construct a stimulus/response (S/R) curve of SI versus SP .The resulting S/R curves were then fitted to a Boltzman function, the best-fit values of which were statistically compared for each experimental condition (i.e., baseline vs. lorazepam vs. flumazenil). Second, a large number of SPs (n=100) was elicited during each of the three experimental conditions using blocks of four stimuli with an intensity alternating between MT and 200% MT. This method was employed so as to reveal the dynamic, time-varying effects of lorazepam and flumazenil on SP duration at two stimulus intensity (SI) levels. MEP recruitment curves were constructed at rest and during activation and fitted to a Boltzman function the best-fit values of which were statistically compared for each experimental condition. Lorazepam at a low dose did not affect Thr, SP, or the active MEP recruitment curves. The high dose also had no effect on Thr and the active MEPs whereas the resting MEP recruitment curves were depressed post-lorazepam at the higher range of stimulus intensities. With regard to SP, the Max value of the S/R curve decreased from 251

  8. Peri-adolescent asthma symptoms cause adult anxiety-related behavior and neurobiological processes in mice.

    PubMed

    Caulfield, Jasmine I; Caruso, Michael J; Michael, Kerry C; Bourne, Rebecca A; Chirichella, Nicole R; Klein, Laura C; Craig, Timothy; Bonneau, Robert H; August, Avery; Cavigelli, Sonia A

    2017-05-30

    Human and animal studies have shown that physical challenges and stressors during adolescence can have significant influences on behavioral and neurobiological development associated with internalizing disorders such as anxiety and depression. Given the prevalence of asthma during adolescence and increased rates of internalizing disorders in humans with asthma, we used a mouse model to test if and which symptoms of adolescent allergic asthma (airway inflammation or labored breathing) cause adult anxiety- and depression-related behavior and brain function. To mimic symptoms of allergic asthma in young BALB/cJ mice (postnatal days [P] 7-57; N=98), we induced lung inflammation with repeated intranasal administration of house dust mite extract (most common aeroallergen for humans) and bronchoconstriction with aerosolized methacholine (non-selective muscarinic receptor agonist). Three experimental groups, in addition to a control group, included: (1) "Airway inflammation only", allergen exposure 3 times/week, (2) "Labored breathing only", methacholine exposure once/week, and (3) "Airway inflammation+Labored breathing", allergen and methacholine exposure. Compared to controls, mice that experienced methacholine-induced labored breathing during adolescence displayed a ∼20% decrease in time on open arms of the elevated plus maze in early adulthood (P60), a ∼30% decrease in brainstem serotonin transporter (SERT) mRNA expression and a ∼50% increase in hippocampal serotonin receptor 1a (5Htr1a) and corticotropin releasing hormone receptor 1 (Crhr1) expression in adulthood (P75). This is the first evidence that experimentally-induced clinical symptoms of adolescent asthma alter adult anxiety-related behavior and brain function several weeks after completion of asthma manipulations. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Sex-dependent effects of periadolescent exposure to the cannabinoid agonist CP-55,940 on morphine self-administration behaviour and the endogenous opioid system.

    PubMed

    Biscaia, Miguel; Fernández, Beatriz; Higuera-Matas, Alejandro; Miguéns, Miguel; Viveros, Maria-Paz; García-Lecumberri, Carmen; Ambrosio, Emilio

    2008-04-01

    Early cannabinoid consumption may predispose individuals to the misuse of addictive drugs later in life. However, there is a lack of experimental evidence as to whether cannabinoid exposure during adolescence might differently affect opiate reinforcing efficacy and the opioid system in adults of both sexes. Our aim was to examine whether periadolescent chronic exposure to the cannabinoid agonist CP-55,940 could exert sex-dependent effects on morphine reinforcing and the opioid system in adulthood. Morphine reinforcing was studied under a progressive ratio (PR) reinforcement schedule in adult male and female rats that previously acquired morphine self-administration under a fixed ratio 1 (FR1) schedule. Binding levels and functionality of mu-opioid receptors were also evaluated. Periadolescent cannabinoid exposure altered morphine self-administration and the opioid system in adult rats in a sex-dependent manner. CP-55,940-exposed males exhibited higher self-administration rates under a FR1, but not under a PR schedule. In females, CP-55,940 did not modify morphine self-administration under either schedule. Moreover, CP-55,940 also increased mu-opioid receptor levels in the subcallosal streak of pre-treated animals and decreased mu-opioid receptor functionality in the nucleus accumbens shell but again, only in males. Our data indicate that adult male rats exposed to the cannabinoid in adolescence self-administer more morphine than females, but only when the demands required by the schedule of reinforcement are low, which might be related to the decrease in mu-opioid receptor functionality in the NAcc-shell observed in these animals.

  10. Laser-induced periodic annular surface structures on fused silica surface

    SciTech Connect

    Liu, Yi; Brelet, Yohann; Forestier, Benjamin; Houard, Aurelien; Yu, Linwei; Deng, Yongkai; Jiang, Hongbing

    2013-06-24

    We report on the formation of laser-induced periodic annular surface structures on fused silica irradiated with multiple femtosecond laser pulses. This surface morphology emerges after the disappearance of the conventional laser induced periodic surface structures, under successive laser pulse irradiation. It is independent of the laser polarization and universally observed for different focusing geometries. We interpret its formation in terms of the interference between the reflected laser field on the surface of the damage crater and the incident laser pulse.

  11. Myeloid cell-specific disruption of Period1 and Period2 exacerbates diet-induced inflammation and insulin resistance.

    PubMed

    Xu, Hang; Li, Honggui; Woo, Shih-Lung; Kim, Sam-Moon; Shende, Vikram R; Neuendorff, Nichole; Guo, Xin; Guo, Ting; Qi, Ting; Pei, Ya; Zhao, Yan; Hu, Xiang; Zhao, Jiajia; Chen, Lili; Chen, Lulu; Ji, Jun-Yuan; Alaniz, Robert C; Earnest, David J; Wu, Chaodong

    2014-06-06

    The circadian clockworks gate macrophage inflammatory responses. Given the association between clock dysregulation and metabolic disorders, we conducted experiments to determine the extent to which over-nutrition modulates macrophage clock function and whether macrophage circadian dysregulation is a key factor linking over-nutrition to macrophage proinflammatory activation, adipose tissue inflammation, and systemic insulin resistance. Our results demonstrate that 1) macrophages from high fat diet-fed mice are marked by dysregulation of the molecular clockworks in conjunction with increased proinflammatory activation, 2) global disruption of the clock genes Period1 (Per1) and Per2 recapitulates this amplified macrophage proinflammatory activation, 3) adoptive transfer of Per1/2-disrupted bone marrow cells into wild-type mice potentiates high fat diet-induced adipose and liver tissue inflammation and systemic insulin resistance, and 4) Per1/2-disrupted macrophages similarly exacerbate inflammatory responses and decrease insulin sensitivity in co-cultured adipocytes in vitro. Furthermore, PPARγ levels are decreased in Per1/2-disrupted macrophages and PPARγ2 overexpression ameliorates Per1/2 disruption-associated macrophage proinflammatory activation, suggesting that this transcription factor may link the molecular clockworks to signaling pathways regulating macrophage polarization. Thus, macrophage circadian clock dysregulation is a key process in the physiological cascade by which diet-induced obesity triggers macrophage proinflammatory activation, adipose tissue inflammation, and insulin resistance.

  12. Myeloid Cell-specific Disruption of Period1 and Period2 Exacerbates Diet-induced Inflammation and Insulin Resistance*

    PubMed Central

    Xu, Hang; Li, Honggui; Woo, Shih-Lung; Kim, Sam-Moon; Shende, Vikram R.; Neuendorff, Nichole; Guo, Xin; Guo, Ting; Qi, Ting; Pei, Ya; Zhao, Yan; Hu, Xiang; Zhao, Jiajia; Chen, Lili; Chen, Lulu; Ji, Jun-Yuan; Alaniz, Robert C.; Earnest, David J.; Wu, Chaodong

    2014-01-01

    The circadian clockworks gate macrophage inflammatory responses. Given the association between clock dysregulation and metabolic disorders, we conducted experiments to determine the extent to which over-nutrition modulates macrophage clock function and whether macrophage circadian dysregulation is a key factor linking over-nutrition to macrophage proinflammatory activation, adipose tissue inflammation, and systemic insulin resistance. Our results demonstrate that 1) macrophages from high fat diet-fed mice are marked by dysregulation of the molecular clockworks in conjunction with increased proinflammatory activation, 2) global disruption of the clock genes Period1 (Per1) and Per2 recapitulates this amplified macrophage proinflammatory activation, 3) adoptive transfer of Per1/2-disrupted bone marrow cells into wild-type mice potentiates high fat diet-induced adipose and liver tissue inflammation and systemic insulin resistance, and 4) Per1/2-disrupted macrophages similarly exacerbate inflammatory responses and decrease insulin sensitivity in co-cultured adipocytes in vitro. Furthermore, PPARγ levels are decreased in Per1/2-disrupted macrophages and PPARγ2 overexpression ameliorates Per1/2 disruption-associated macrophage proinflammatory activation, suggesting that this transcription factor may link the molecular clockworks to signaling pathways regulating macrophage polarization. Thus, macrophage circadian clock dysregulation is a key process in the physiological cascade by which diet-induced obesity triggers macrophage proinflammatory activation, adipose tissue inflammation, and insulin resistance. PMID:24770415

  13. Endogenous insulin fluctuations during glucose-induced paralysis in patients with familial periodic hypokalemia.

    PubMed

    Johnsen, T

    1977-11-01

    Endogenous insulin production in patients with familial periodic hypokalemia has not previously been studied during induced attacks. The serum insulin, serum potassium, and blood glucose concentrations were measured in six patients with familial periodic hypokalemia during six attacks of paralysis induced by long-lasting glucose stimulation. The same parameters were measured in four normal subjects under the same conditions. There was no difference in insulin response or in blood glucose between the two groups. Basal insulin levels showed no difference. There was no correlation between the occurrence of the attack and the serum insulin level in the patients. All the patients responded by severe paralysis and hypokalemia.

  14. Ultraviolet and infrared femtosecond laser induced periodic surface structures on thin polymer films

    SciTech Connect

    Rebollar, Esther; Castillejo, Marta; Vazquez de Aldana, Javier R.; Moreno, Pablo

    2012-01-23

    This work demonstrates the formation of femtosecond laser induced periodic surface structures (LIPSS) by multipulse irradiation with the fundamental and 3rd harmonic of a linearly polarized Ti:sapphire laser (795 and 265 nm) on thin films of the polymers poly (ethylene terephthalate), poly (trimethylene terephthalate), and poly (carbonate bisphenol A) prepared by spin-coating. LIPSS, inspected by atomic force microscopy, are formed upon multiple pulse UV and IR irradiation with wavelength-sized period in a narrow range of fluences below the ablation threshold. Control and tunability of the size and morphology of the periodic structures become thus possible ensuring photochemical integrity of polymer films.

  15. Wavelength dependence of picosecond laser-induced periodic surface structures on copper

    NASA Astrophysics Data System (ADS)

    Maragkaki, Stella; Derrien, Thibault J.-Y.; Levy, Yoann; Bulgakova, Nadezhda M.; Ostendorf, Andreas; Gurevich, Evgeny L.

    2017-09-01

    The physical mechanisms of the laser-induced periodic surface structures (LIPSS) formation are studied in this paper for single-pulse irradiation regimes. The change in the LIPSS period with wavelength of incident laser radiation is investigated experimentally, using a picosecond laser system, which provides 7-ps pulses in near-IR, visible, and UV spectral ranges. The experimental results are compared with predictions made under the assumption that the surface-scattered waves are involved in the LIPSS formation. Considerable disagreement suggests that hydrodynamic mechanisms can be responsible for the observed pattern periodicity.

  16. Thyroid hormone alleviates demyelination induced by cuprizone through its role in remyelination during the remission period.

    PubMed

    Zhang, Mao; Zhan, Xiao L; Ma, Zi Y; Chen, Xing S; Cai, Qi Y; Yao, Zhong X

    2015-09-01

    Multiple sclerosis (MS) is a disease induced by demyelination in the central nervous system, and the remission period of MS is crucial for remyelination. In addition, abnormal levels of thyroid hormone (TH) have been identified in MS. However, in the clinic, insufficient attention has been paid to the role of TH in the remission period. Indeed, TH not only functions in the development of the brain but also affects myelination. Therefore, it is necessary to observe the effect of TH on remyelination during this period. A model of demyelination induced by cuprizone (CPZ) was used to observe the function of TH in remyelination during the remission period of MS. Through weighing and behavioral tests, we found that TH improved the physical symptoms of mice impaired by CPZ. Supplementation of TH led to the repair of myelin as detected by immunohistochemistry and western blot. In addition, a sufficient TH supply resulted in an increase in myelinated axons without affecting myelin thickness and g ratio in the corpus callosum, as detected by electron microscopy. Double immunostaining with myelin basic protein and neurofilament 200 (NF200) showed that the CPZ-induced impairment of axons was alleviated by TH. Conversely, insufficient TH induced by 6-propyl-2-thiouracil resulted in the enlargement of mitochondria. Furthermore, we found that an adequate supply of TH promoted the proliferation and differentiation of oligodendrocyte lineage cells by immunofluorescence, which was beneficial to remyelination. Further, we found that TH reduced the number of astrocytes without affecting microglia. Conclusively, it was shown that TH alleviated demyelination induced by CPZ by promoting the development of oligodendrocyte lineage cells and remyelination. The critical time for remyelination is the remission period of MS. TH plays a significant role in alleviating demyelination during the remission period in the clinical treatment of MS.

  17. CO2-Laser-Induced Regular Periodic Structures on Glass Substrates

    NASA Astrophysics Data System (ADS)

    Peng, Yingzi; An, Chengwu; Hong, Minghui; Lu, Yongfeng; Chong, Tow-chong

    2003-11-01

    A CW CO2 laser was used to induce regular and tidy periodic structures on glass substrates. It is experimentally shown that the wave vector of the ripples is perpendicular to the recording polarization irrespective of the scanning direction. The occurrence of periodic structures is highly sensitive to laser power level and scanning velocity. To obtain appropriate periodic patterns, a combined condition of laser power and scanning velocity must be satisfied. Different directions of laser scanning lead to different occurrence areas. Different kinds of materials seem to develop the occurrence areas with almost similar shape, but their relative positions and dimensions may be different. The maximum laser scanning velocity range to form regular and tidy periodic structures appears at the optimum power condition. Moreover, the maximum period could be obtained at this optimum condition.

  18. DETECTION OF A CRITICAL PERIOD NECESSARY FOR ATRAZINE-INDUCED MAMMARY GLAND DELAYS IN RATS

    EPA Science Inventory

    Detection of a Critical Period Necessary for Atrazine-Induced Mammary Gland Delays in Rats.

    Jennifer L. Rayner1 and Suzanne E. Fenton2

    1 University of North Carolina at Chapel Hill, DESE, Chapel Hill, NC, and 2 Reproductive Toxicology Division, USEPA, NHEERL/ORD, R...

  19. DETECTION OF A CRITICAL PERIOD NECESSARY FOR ATRAZINE-INDUCED MAMMARY GLAND DELAYS IN RATS

    EPA Science Inventory

    Detection of a Critical Period Necessary for Atrazine-Induced Mammary Gland Delays in Rats.

    Jennifer L. Rayner1 and Suzanne E. Fenton2

    1 University of North Carolina at Chapel Hill, DESE, Chapel Hill, NC, and 2 Reproductive Toxicology Division, USEPA, NHEERL/ORD, R...

  20. The mathematical model that describes the periodic spouting of a geyser induced by boiling

    NASA Astrophysics Data System (ADS)

    Kagami, Hiroyuki

    2017-04-01

    We have derived and modified the dynamical model of a geyser induced by gas inflow and regular or irregular spouting dynamics of geysers induced by gas inflow has been reproduced by the model. On the other hand, though we have derived the dynamical model of a geyser induced by boiling, periodic change between the spouting state and the pause state has not been adequately modeled by the model. In this connection, concerning a geyser induced by gas inflow we have proposed the model as described below. Because pressure in the spouting tube decreases obeying to the Bernoulli's theorem when the spouting state begins and water in the spouting tube begins to flow, inflow of groundwater into the spouting tube occurs. When the amount of this inflow reaches a certain amount, the spouting state transforms to the pause state. In this study, by applying this idea to the dynamical model of a geyser induced by boiling, the periodic change between the spouting state and the pause state could be reappeared. As a result, the whole picture of the spouting mechanism of a geyser induced by boiling became clear. This research results would give hints on engineering repair in order to prevent the weakening or the depletion of the geyser. And this study would be also useful for protection of geysers as tourism and environmental resources.

  1. High spatial frequency periodic structures induced on metal surface by femtosecond laser pulses.

    PubMed

    Yao, Jian-Wu; Zhang, Cheng-Yun; Liu, Hai-Ying; Dai, Qiao-Feng; Wu, Li-Jun; Lan, Sheng; Gopal, Achanta Venu; Trofimov, Vyacheslav A; Lysak, Tatiana M

    2012-01-16

    The high spatial frequency periodic structures induced on metal surface by femtosecond laser pulses was investigated experimentally and numerically. It is suggested that the redistribution of the electric field on metal surface caused by the initially formed low spatial frequency periodic structures plays a crucial role in the creation of high spatial frequency periodic structures. The field intensity which is initially localized in the grooves becomes concentrated on the ridges in between the grooves when the depth of the grooves exceeds a critical value, leading to the ablation of the ridges in between the grooves and the formation of high spatial frequency periodic structures. The proposed formation process is supported by both the numerical simulations based on the finite-difference time-domain technique and the experimental results obtained on some metals such as stainless steel and nickel.

  2. Modeling laser-induced periodic surface structures: Finite-difference time-domain feedback simulations

    SciTech Connect

    Skolski, J. Z. P. Vincenc Obona, J.; Römer, G. R. B. E.; Huis in 't Veld, A. J.

    2014-03-14

    A model predicting the formation of laser-induced periodic surface structures (LIPSSs) is presented. That is, the finite-difference time domain method is used to study the interaction of electromagnetic fields with rough surfaces. In this approach, the rough surface is modified by “ablation after each laser pulse,” according to the absorbed energy profile, in order to account for inter-pulse feedback mechanisms. LIPSSs with a periodicity significantly smaller than the laser wavelength are found to “grow” either parallel or orthogonal to the laser polarization. The change in orientation and periodicity follow from the model. LIPSSs with a periodicity larger than the wavelength of the laser radiation and complex superimposed LIPSS patterns are also predicted by the model.

  3. Formation of laser-induced periodic surface structures on niobium by femtosecond laser irradiation

    SciTech Connect

    Pan, A.; Dias, A.; Gomez-Aranzadi, M.; Olaizola, S. M.; Rodriguez, A.

    2014-05-07

    The surface morphology of a Niobium sample, irradiated in air by a femtosecond laser with a wavelength of 800 nm and pulse duration of 100 fs, was examined. The period of the micro/nanostructures, parallel and perpendicularly oriented to the linearly polarized fs-laser beam, was studied by means of 2D Fast Fourier Transform analysis. The observed Laser-Induced Periodic Surface Structures (LIPSS) were classified as Low Spatial Frequency LIPSS (periods about 600 nm) and High Spatial Frequency LIPSS, showing a periodicity around 300 nm, both of them perpendicularly oriented to the polarization of the incident laser wave. Moreover, parallel high spatial frequency LIPSS were observed with periods around 100 nm located at the peripheral areas of the laser fingerprint and overwritten on the perpendicular periodic gratings. The results indicate that this method of micro/nanostructuring allows controlling the Niobium grating period by the number of pulses applied, so the scan speed and not the fluence is the key parameter of control. A discussion on the mechanism of the surface topology evolution was also introduced.

  4. Development of solenoid-induced helical wiggler with four poles per period

    NASA Astrophysics Data System (ADS)

    Ohigashi, N.; Tsunawaki, Y.; Kiyochi, M.; Nakao, N.; Fujita, M.; Imasaki, K.; Nakai, S.; Mima, K.

    1999-06-01

    A new type of helical wiggler consisting of two staggered-iron arrays inserted into a solenoid field has been developed. The field measured by a test wiggler showed linear increment with the period. It was seen that 24% of the solenoid field contributed to the induced wiggler field when the gap length and the period of the wiggler were 16 and 24 mm, respectively. This wiggler would be useful for an FEL with a low-energy electron beam propagating in a strong axial guiding field.

  5. Storm-induced damages along the Catalan coast (NW Mediterranean) during the period 1958-2008

    NASA Astrophysics Data System (ADS)

    Jiménez, José A.; Sancho-García, Amanda; Bosom, Eva; Valdemoro, Herminia I.; Guillén, Jorge

    2012-03-01

    The temporal and spatial patterns of storm-induced damage along the Catalan coast (NW Mediterranean) during the last 50 years have been analyzed to identify main climatic and non-climatic forcings. In the absence of systematic data, a storm-induced damage database compiled from press news has been built, which together with an intensity scale has allowed us to characterize the frequency and intensity of damage. Although no temporal trend has been detected in storm-induced hazards, coastal damage has increased at a rate of about 40% per decade during the last 50 years along the Catalan coast. The main non-climatic factors identified controlling this trend were the urban growth along the coastal fringe and the generalized erosive behavior of beaches. The first one increased values at risk and the second one increased their exposure to storm-induced hazards. In spite of the importance of non-climatic factors to modulate coastal damage, an exponential dependence of damages on storm-induced inundation and erosion was detected. In addition to this, storm-induced geomorphic changes along the Ebro delta coast have also been analyzed. During the period analyzed, "harmful" storms seem to be clustered, with most of the events being present in the late 1990s and especially from 2001 to 2004, resulting in frequent events of intense beach/barrier breaching, massive overwash and flooding. They are mainly expressed in sensitive areas which are subject to long-term erosional processes and comprise a low-lying profile and a narrow beach. This reflects the role of coastal morphology in controlling the intensity of storm-induced hazards along the deltaic coast. Shoreline evolution rates calculated during this period were significantly larger than the previously recorded ones, reflecting a pulsating erosion behavior where large pulses occur during stormy periods and are reduced during post-storm periods. Under the present scenario of maximum coastal development, storm-induced damage

  6. Laser-induced periodic alignment of Ag nanoparticles in soda-lime glass.

    PubMed

    Goutaland, François; Colombier, Jean-Philippe; Sow, Mohamed Cherif; Ollier, Nadège; Vocanson, Francis

    2013-12-30

    One-, two- or three-dimensional arrays of closely spaced silver nanoparticles may lead to new optical properties, due to short or long range coupling between their resonant surface plasmons, so that the spatially controlled growth of silver nanoparticles provides an efficient way to tune their optical properties. Towards this way, we present here the periodic pattern of a glass surface with silver nanoparticles by continuous ultraviolet laser exposure. The formation of the 160 nm period pattern is well described by an interference-based model which agrees with the experimental conclusions, mainly obtained by various forms of microscopy. Statistical approach based on the autocorrelation function gives quantitative description about the quality of the order in the periodic structure and about the nanoparticles averaged diameter (80 nm). We also present the optical extinction spectrum of the Laser Induced Periodic Surface Structure (LIPSS)-containing area of the glass, which unusually shows several bands in the visible range. The period of 160 nm of the periodic structure is short enough to allow coupling between nanoparticles, which makes it a possible candidate for plasmon-based optical applications.

  7. Impulse-induced optimum control of escape from a metastable state by periodic secondary excitations.

    PubMed

    Chacón, R; Martínez, J A; Miralles, J J

    2012-06-01

    We characterize the role of the impulse transmitted (time integral over a half-period) by resonant secondary excitations at controlling (suppressing and enhancing) escape from a potential well, which is induced by periodic primary excitations. By using the universal model of a dissipative Helmholtz oscillator, we demonstrate numerically that optimum control of escape occurs when the impulse transmitted by the chaos-controlling excitations is maximum while keeping their amplitude and period fixed. These findings are in complete agreement with analytical predictions from two independent methods: Melnikov analysis and energy-based analysis. Additional numerical results corresponding to other alternative escape-controlling excitations demonstrate the generality of the essential role of the excitation's impulse.

  8. Laser induced periodic surface structures on pyrolytic carbon prosthetic heart valve

    NASA Astrophysics Data System (ADS)

    Stepak, Bogusz D.; Łecka, Katarzyna M.; Płonek, Tomasz; Antończak, Arkadiusz J.

    2016-12-01

    Laser-induced periodic surface structures (LIPSS) can appear in different forms such as ripples, grooves or cones. Those highly periodic wavy surface features which are frequently smaller than incident light wavelength bring possibility of nanostructuring of many different materials. Furthermore, by changing laser parameters one can obtain wide spectrum of periodicities and geometries. The aim of this research was to determine possibility of nanostructuring pyrolytic carbon (PyC) heart valve leaflets using different irradiation conditions. The study was performed using two laser sources with different pulse duration (15 ps, 450 fs) as well as different wavelengths (1064, 532, 355 nm). Both low and high spatial frequency LIPSS were observed for each set of irradiation parameters. In case femtosecond laser pulses we obtained deep subwavelength ripple period which was even ten times smaller than applied wavelength. Obtained ripple period was ranging from 90 up to 860 nm. Raman spectra revealed the increase of disorder after laser irradiation which was comparable for both pico- and femtosecond laser.

  9. Periodic Cavitation in a High-Speed Water Inducer at an Off-Design Flow Coefficient

    NASA Astrophysics Data System (ADS)

    Lundgreen, Ryan; Cluff, Ryan; Maynes, Daniel; Gorrell, Steven; Oliphant, Kerry

    2012-11-01

    Time resolved numerical simulations were conducted on a high-speed water inducer designed to operate under cavitating conditions at both on and off-design flow rates. A segregated solver was employed and the turbulence model was the realizable k-epsilon approach. The solution discretization is second order accurate in space and first order accurate in time. Cavitation within the domain becomes periodic as the cavitation number decreases. At flow coefficients smaller than the design flow coefficient, a large time-varying volume of cavitation is observed upstream of the inducer causing the system to become unstable for practical use. Large regions of reversed flow at the blade tip cause the incoming fluid to increase in velocity and the effective mass flow area to decrease. It is this increase in velocity that leads to the formation of the periodic vapor cavity upstream of the inducer. The vapor cavity increases in size until it completely blocks the core of the passage, forcing the flow out toward the shroud. As the flow near the shroud accelerates, the reversed flow at the blade tip decreases and the vapor cavity decreases in size until it collapse completely, causing a large jump in pressure throughout the entire flow domain.

  10. Effects of ceftriaxone on the acquisition and maintenance of ethanol drinking in peri-adolescent and adult female alcohol-preferring (P) rats

    PubMed Central

    Sari, Youssef; Franklin, Kelle M.; Alazizi, Adnan; Rao, P.S.S.; Bell, Richard L.

    2013-01-01

    Increased glutamatergic neurotransmission appears to mediate the reinforcing properties of drugs of abuse, including ethanol (EtOH). We recently reported that the administration of ceftriaxone (CEF), a β-lactam antibiotic known to upregulate glutamate transporter 1 (GLT1) levels/activity, decreased the maintenance of EtOH intake in adult male alcohol-preferring (P) rats. In the present study, we tested whether CEF administration would reduce the acquisition and maintenance of EtOH drinking in adolescent and adult female P rats. The rats were treated with saline or 200 mg/kg ceftriaxone for 7 days (starting at 35 or 75 days old, respectively) followed by the EtOH acquisition test. Five weeks later the effects of CEF were examined regarding the maintenance of EtOH intake. For the maintenance test, half of the animals that received CEF during acquisition received CEF for 7 days and the other half received saline for 7 days. Saline-treated acquisition animals were treated similarly. The results indicated that pretreatment with ceftriaxone reduced the maintenance of EtOH intake in both animals that started as adolescents and those that started as adults. However, the beneficial effect of CEF was more pronounced in rats pretreated with CEF as adults compared with rats pretreated as adolescents. Reductions in EtOH intake by ceftriaxone were paralleled by an upregulation of GLT1 protein levels in both the nucleus accumbens (µ25% in rats starting at both ages) and prefrontal cortex (µ50% in rats starting as peri-adolescents and µ65% in those starting as adults). These findings provide further support for GLT1-associated mechanisms in high alcohol consuming behavior, and hold promise for the development of effective treatments targeting alcohol abuse and dependence. PMID:23537837

  11. Induced cooperative motions in a medium driven at the nanoscale: searching for an optimum excitation period.

    PubMed

    Teboul, V; Accary, J B

    2014-01-01

    Recent results have shown the appearance of induced cooperative motions called dynamic heterogeneity during the isomerization of diluted azobenzene molecules in a host glass-former. In this paper, we raise the issue of the coupling between these "artificial" heterogeneities and the isomerization period. How do these induced heterogeneities differ in the saturation regime and in the linear response regime? Is there a maximum of the heterogeneous motion versus the isomerization rate, and why? Is the heterogeneity evolution with the isomerization rate connected with the diffusion or relaxation time evolution? We use out-of-equilibrium molecular dynamics simulations to answer these questions. We find that the heterogeneity increases in the linear response regime for large isomerization periods and small perturbations. In contrast, the heterogeneity decreases in the saturation regime, i.e., when the isomerization half-period (τp/2) is smaller than the relaxation time of the material (τα). This result enables a test of the effect of cooperative motions on the dynamics using the chromophores as Maxwell demons that destroy or stimulate the cooperative motions. Because the heterogeneities increase in the linear regime and then decrease in the saturation regime, we find a maximum for τp/2≈τα. The induced excitation concentration follows a power-law evolution versus the isomerization rate and then saturates. As a consequence, the α relaxation time is related to the excitation concentration with a power law, a result in qualitative agreement with recent findings in constrained models. This result supports a common origin for the heterogeneities with constrained models and a similar relation to the excitation concentration.

  12. Polarization dependent formation of femtosecond laser-induced periodic surface structures near stepped features

    SciTech Connect

    Murphy, Ryan D.; Torralva, Ben; Adams, David P.; Yalisove, Steven M.

    2014-06-09

    Laser-induced periodic surface structures (LIPSS) are formed near 110 nm-tall Au microstructured edges on Si substrates after single-pulse femtosecond irradiation with a 150 fs pulse centered near a 780 nm wavelength. We investigate the contributions of Fresnel diffraction from step-edges and surface plasmon polariton (SPP) excitation to LIPSS formation on Au and Si surfaces. For certain laser polarization vector orientations, LIPSS formation is dominated by SPP excitation; however, when SPP excitation is minimized, Fresnel diffraction dominates. The LIPSS orientation and period distributions are shown to depend on which mechanism is activated. These results support previous observations of the laser polarization vector influencing LIPSS formation on bulk surfaces.

  13. Bio-Inspired Functional Surfaces Based on Laser-Induced Periodic Surface Structures

    PubMed Central

    Müller, Frank A.; Kunz, Clemens; Gräf, Stephan

    2016-01-01

    Nature developed numerous solutions to solve various technical problems related to material surfaces by combining the physico-chemical properties of a material with periodically aligned micro/nanostructures in a sophisticated manner. The utilization of ultra-short pulsed lasers allows mimicking numerous of these features by generating laser-induced periodic surface structures (LIPSS). In this review paper, we describe the physical background of LIPSS generation as well as the physical principles of surface related phenomena like wettability, reflectivity, and friction. Then we introduce several biological examples including e.g., lotus leafs, springtails, dessert beetles, moth eyes, butterfly wings, weevils, sharks, pangolins, and snakes to illustrate how nature solves technical problems, and we give a comprehensive overview of recent achievements related to the utilization of LIPSS to generate superhydrophobic, anti-reflective, colored, and drag resistant surfaces. Finally, we conclude with some future developments and perspectives related to forthcoming applications of LIPSS-based surfaces. PMID:28773596

  14. Stimulus-induced rhythmic, periodic, or ictal discharges (SIRPIDs): an intriguing EEG phenomenon.

    PubMed

    Silveira, Mariana Ribeiro Marcondes da; Andrade, Joaquina; Garzon, Eliana

    2013-12-01

    SIRPIDs, an acronym for stimulus-induced rhythmic, periodic, or ictal discharges, were first named in 2004. This is a pattern observed in continuous electroencephalogram (CEEG) consistently elicited by stimulation in comatose patients. The pathophysiology of SIRPIDs probably involves dysregulation of subcortico-cortical projections, particularly thalamocortical circuit, in a markedly abnormal brain with hyperexci-table cortex. This may explain some studies found an association of prolonged periodic epileptiform discharges (PEDs) activity and a higher incidence of concurrent electrographic seizures and SIRPIDs. An association of SIRPIDs and poor prognosis has already been described. However, it is not yet possible to assert whether these discharges can cause neuronal injury or if they are simply a marker of severe brain injury. Objective of this paper is to review clinical relevance and pathophysiology of SIRPIDs, as well as its role as a brain response in the critically ill patient.

  15. Fluctuations induced extinction and stochastic resonance effect in a model of tumor growth with periodic treatment

    NASA Astrophysics Data System (ADS)

    Li, Dongxi; Xu, Wei; Guo, Yongfeng; Xu, Yong

    2011-01-01

    We investigate a stochastic model of tumor growth derived from the catalytic Michaelis-Menten reaction with positional and environmental fluctuations under subthreshold periodic treatment. Firstly, the influences of environmental fluctuations on the treatable stage are analyzed numerically. Applying the standard theory of stochastic resonance derived from the two-state approach, we derive the signal-to-noise ratio (SNR) analytically, which is used to measure the stochastic resonance phenomenon. It is found that the weak environmental fluctuations could induce the extinction of tumor cells in the subthreshold periodic treatment. The positional stability is better in favor of the treatment of the tumor cells. Besides, the appropriate and feasible treatment intensity and the treatment cycle should be highlighted considered in the treatment of tumor cells.

  16. Periodic surface structure bifurcation induced by ultrafast laser generated point defect diffusion in GaAs

    SciTech Connect

    Abere, Michael J.; Yalisove, Steven M.; Torralva, Ben

    2016-04-11

    The formation of high spatial frequency laser induced periodic surface structures (HSFL) with period <0.3 λ in GaAs after irradiation with femtosecond laser pulses in air is studied. We have identified a point defect generation mechanism that operates in a specific range of fluences in semiconductors between the band-gap closure and ultrafast-melt thresholds that produces vacancy/interstitial pairs. Stress relaxation, via diffusing defects, forms the 350–400 nm tall and ∼90 nm wide structures through a bifurcation process of lower spatial frequency surface structures. The resulting HSFL are predominately epitaxial single crystals and retain the original GaAs stoichiometry.

  17. Bio-Inspired Functional Surfaces Based on Laser-Induced Periodic Surface Structures.

    PubMed

    Müller, Frank A; Kunz, Clemens; Gräf, Stephan

    2016-06-15

    Nature developed numerous solutions to solve various technical problems related to material surfaces by combining the physico-chemical properties of a material with periodically aligned micro/nanostructures in a sophisticated manner. The utilization of ultra-short pulsed lasers allows mimicking numerous of these features by generating laser-induced periodic surface structures (LIPSS). In this review paper, we describe the physical background of LIPSS generation as well as the physical principles of surface related phenomena like wettability, reflectivity, and friction. Then we introduce several biological examples including e.g., lotus leafs, springtails, dessert beetles, moth eyes, butterfly wings, weevils, sharks, pangolins, and snakes to illustrate how nature solves technical problems, and we give a comprehensive overview of recent achievements related to the utilization of LIPSS to generate superhydrophobic, anti-reflective, colored, and drag resistant surfaces. Finally, we conclude with some future developments and perspectives related to forthcoming applications of LIPSS-based surfaces.

  18. Periodic force induced stabilization or destabilization of the denatured state of a protein

    NASA Astrophysics Data System (ADS)

    Ghosh, Pulak Kumar; Li, Mai Suan; Bag, Bidhan Chandra

    2011-09-01

    We have studied the effects of an external sinusoidal force in protein folding kinetics. The externally applied force field acts on the each amino acid residues of polypeptide chains. Our simulation results show that mean protein folding time first increases with driving frequency and then decreases passing through a maximum. With further increase of the driving frequency the mean folding time starts increasing as the noise-induced hoping event (from the denatured state to the native state) begins to experience many oscillations over the mean barrier crossing time period. Thus unlike one-dimensional barrier crossing problems, the external oscillating force field induces both stabilization or destabilization of the denatured state of a protein. We have also studied the parametric dependence of the folding dynamics on temperature, viscosity, non-Markovian character of bath in presence of the external field.

  19. Nanosecond laser-induced periodic surface structuring of cross-linked azo-polymer films

    NASA Astrophysics Data System (ADS)

    Berta, Marco; Biver, Émeric; Maria, Sébastien; Phan, Trang N. T.; D'Aleo, Anthony; Delaporte, Philippe; Fages, Frederic; Gigmes, Didier

    2013-10-01

    In this work we discuss the response to laser ablation of a poly(4-vinylbenzyl azide-random-methyl methacrylate) (p((S-N3)-r-MMA)) random copolymer. This material is cross-linkable thermally and upon exposure to UV light, and on cross-linked films the irradiation with a 248 nm ns KrF laser induces the formation of laser induced periodical surface structure (LIPSS). The LIPSS morphology is dependent on the amount of 4-vinylbenzyl azide (S-N3) groups in the pristine copolymer. We propose a crosslinking mechanism based on the scission of azide with formation of azo groups and we discuss the possible relationship between this chemical modifications and the formation of ripples on the bottom of laser ablation cavities.

  20. Ultrafast laser induced periodic sub-wavelength aluminum surface structures and nanoparticles in air and liquids

    NASA Astrophysics Data System (ADS)

    Kuladeep, Rajamudili; Dar, Mudasir H.; Deepak, K. L. N.; Rao, D. Narayana

    2014-09-01

    In this communication, we demonstrate the generation of laser-induced periodic sub-wavelength surface structures (LIPSS) or ripples on a bulk aluminum (Al) and Al nanoparticles (NPs) by femtosecond (fs) laser direct writing technique. Laser irradiation was performed on Al surface at normal incidence in air and by immersing in ethanol (C2H5OH) and water (H2O) using linearly polarized Ti:sapphire fs laser pulses of ˜110 fs pulse duration and ˜800 nm wavelength. Field emission scanning electron microscope is utilized for imaging surface morphology of laser written structures and it reveals that the spatial periodicity as well as the surface morphology of the LIPSS depends on the surrounding dielectric medium and also on the various laser irradiation parameters. The observed LIPSS have been classified as low spatial frequency LIPSS which are perpendicularly oriented to the laser polarization with a periodicity from 460 to 620 nm and high spatial frequency LIPSS which spectacles a periodicity less than 100 nm with the orientation parallel to the polarization of the incident laser beam. Fabricated colloidal solutions, which contain the Al NPs, were characterized by UV-Vis absorption spectroscopy and transmission electron microscopy (TEM). TEM results reveal the formation of internal cavities in Al NPs both in ethanol and water. Formation mechanism of LIPSS and cavities inside the nanoparticles are discussed in detail.

  1. Ultrafast laser induced periodic sub-wavelength aluminum surface structures and nanoparticles in air and liquids

    SciTech Connect

    Kuladeep, Rajamudili; Dar, Mudasir H.; Rao, D. Narayana E-mail: dnr-laserlab@yahoo.com; Deepak, K. L. N.

    2014-09-21

    In this communication, we demonstrate the generation of laser-induced periodic sub-wavelength surface structures (LIPSS) or ripples on a bulk aluminum (Al) and Al nanoparticles (NPs) by femtosecond (fs) laser direct writing technique. Laser irradiation was performed on Al surface at normal incidence in air and by immersing in ethanol (C₂H₅OH) and water (H₂O) using linearly polarized Ti:sapphire fs laser pulses of ~110 fs pulse duration and ~800 nm wavelength. Field emission scanning electron microscope is utilized for imaging surface morphology of laser written structures and it reveals that the spatial periodicity as well as the surface morphology of the LIPSS depends on the surrounding dielectric medium and also on the various laser irradiation parameters. The observed LIPSS have been classified as low spatial frequency LIPSS which are perpendicularly oriented to the laser polarization with a periodicity from 460 to 620 nm and high spatial frequency LIPSS which spectacles a periodicity less than 100 nm with the orientation parallel to the polarization of the incident laser beam. Fabricated colloidal solutions, which contain the Al NPs, were characterized by UV-Vis absorption spectroscopy and transmission electron microscopy (TEM). TEM results reveal the formation of internal cavities in Al NPs both in ethanol and water. Formation mechanism of LIPSS and cavities inside the nanoparticles are discussed in detail.

  2. Finite-difference Time-domain Modeling of Laser-induced Periodic Surface Structures

    NASA Astrophysics Data System (ADS)

    Römer, G. R. B. E.; Skolski, J. Z. P.; Oboňa, J. Vincenc; Veld, A. J. Huis in't.

    Laser-induced periodic surface structures (LIPSSs) consist of regular wavy surface structures with amplitudes the (sub)micrometer range and periodicities in the (sub)wavelength range. It is thought that periodically modulated absorbed laser energy is initiating the growth of LIPSSs. The "Sipe theory" (or "Efficacy factor theory") provides an analytical model of the interaction of laser radiation with a rough surface of the material, predicting modulated absorption just below the surface of the material. To address some limitations of this model, the finite-difference time-domain (FDTD) method was employed to numerically solve the two coupled Maxwell's curl equations, for linear, isotropic, dispersive materials with no magnetic losses. It was found that the numerical model predicts the periodicity and orientation of various types of LIPSSs which might occur on the surface of the material sample. However, it should be noted that the numerical FDTD model predicts the signature or "fingerprints" of several types of LIPSSs, at different depths, based on the inhomogeneously absorbed laser energy at those depths. Whether these types of (combinations of) LIPSSs will actually form on a material will also depend on other physical phenomena, such as the excitation of the material, as well as thermal-mechanical phenomena, such as the state and transport of the material.

  3. Infrared light-induced protein crystallization. Structuring of protein interfacial water and periodic self-assembly

    NASA Astrophysics Data System (ADS)

    Kowacz, Magdalena; Marchel, Mateusz; Juknaité, Lina; Esperança, José M. S. S.; Romão, Maria João; Carvalho, Ana Luísa; Rebelo, Luís Paulo N.

    2017-01-01

    We show that a physical trigger, a non-ionizing infrared (IR) radiation at wavelengths strongly absorbed by liquid water, can be used to induce and kinetically control protein (periodic) self-assembly in solution. This phenomenon is explained by considering the effect of IR light on the structuring of protein interfacial water. Our results indicate that the IR radiation can promote enhanced mutual correlations of water molecules in the protein hydration shell. We report on the radiation-induced increase in both the strength and cooperativeness of H-bonds. The presence of a structured dipolar hydration layer can lead to attractive interactions between like-charged biomacromolecules in solution (and crystal nucleation events). Furthermore, our study suggests that enveloping the protein within a layer of structured solvent (an effect enhanced by IR light) can prevent the protein non-specific aggregation favoring periodic self-assembly. Recognizing the ability to affect protein-water interactions by means of IR radiation may have important implications for biological and bio-inspired systems.

  4. Mechanically induced long period fiber gratings on single mode tapered optical fiber for structure sensing applications

    NASA Astrophysics Data System (ADS)

    Pulido-Navarro, María. G.; Marrujo-García, Sigifredo; Álvarez-Chávez, José A.; Velázquez-González, Jesús S.; Martínez-Piñón, Fernando; Escamilla-Ambrosio, Ponciano J.

    2015-08-01

    The modal characteristics of tapered single mode optical fibers and its strain sensing characteristics by using mechanically induced long period fiber gratings are presented in this work. Both Long Period Fiber Gratings (LPFG) and fiber tapers are fiber devices that couple light from the core fiber into the fiber cladding modes. The mechanical LPFG is made up of two plates, one flat and the other grooved. For this experiment the grooved plate was done on an acrylic slab with the help of a computer numerical control machine. The manufacturing of the tapered fiber is accomplished by applying heat using an oxygen-propane flame burner and stretching the fiber, which protective coating has been removed. Then, a polymer-tube-package is added in order to make the sensor sufficiently stiff for the tests. The mechanical induced LPFG is accomplished by putting the tapered fiber in between the two plates, so the taper acquires the form of the grooved plate slots. Using a laser beam the transmission spectrum showed a large peak transmission attenuation of around -20 dB. The resultant attenuation peak wavelength in the transmission spectrum shifts with changes in tension showing a strain sensitivity of 2pm/μɛ. This reveals an improvement on the sensitivity for structure monitoring applications compared with the use of a standard optical fiber. In addition to the experimental work, the supporting theory and numerical simulation analysis are also included.

  5. An atomic force microscopy statistical analysis of laser-induced azo-polyimide periodic tridimensional nanogrooves.

    PubMed

    Stoica, Iuliana; Epure, Luiza; Sava, Ion; Damian, Victor; Hurduc, Nicolae

    2013-09-01

    The surface morphology of azo-polyimide films was investigated after 355 nm Nd: YAG laser irradiation with two different incident fluencies. Atomic force microscopy (AFM) was employed to correlate the laser-induced tridimensional nanogrooved surface relief with the incident fluence and the number of irradiation pulses. The height images revealed that the grooves depth increased even tens of times by increasing the incident fluence, using the same numbers of irradiation pulses. For low incident fluence, the films were uniformly patterned till 100 pulses of irradiation. Instead, when using higher fluence, after 15 pulses of irradiation the accuracy of the surface relief definition was reduced. This behavior could be explained by means of two different mechanisms, one that suppose the film photo-fluidization due to the cis-trans isomerization processes of the azo-groups and the second one responsible for the directional mass displacement. The dominant surface direction and parameters like isotropy, periodicity, and period were evaluated from the polar representation for texture analysis, revealing the appearance of ordered and directionated nanostructures for most of the experimental conditions. Also, the graphical studies of the functional volume parameters have evidenced the improvement of the relief structuration during surface nanostructuration. The correlation of these statistical texture parameters with the irradiation characteristics is important in controlling the alignment of either the liquid crystals or the cells/tissues on patterned azo-polyimide surfaces for optoelectronic devices and implantable biomaterials, respectively. Copyright © 2013 Wiley Periodicals, Inc.

  6. Femtosecond laser-induced periodic surface structure on the Ti-based nanolayered thin films

    SciTech Connect

    Petrović, Suzana M.; Gaković, B.; Peruško, D.; Stratakis, E.; Bogdanović-Radović, I.; Čekada, M.; Fotakis, C.; Jelenković, B.

    2013-12-21

    Laser-induced periodic surface structures (LIPSSs) and chemical composition changes of Ti-based nanolayered thin films (Al/Ti, Ni/Ti) after femtosecond (fs) laser pulses action were studied. Irradiation is performed using linearly polarized Ti:Sapphire fs laser pulses of 40 fs pulse duration and 800 nm wavelength. The low spatial frequency LIPSS (LSFL), oriented perpendicular to the laser polarization with periods slightly lower than the irradiation wavelength, was typically formed at elevated laser fluences. On the contrary, high spatial frequency LIPSS (HSFL) with uniform period of 155 nm, parallel to the laser light polarization, appeared at low laser fluences, as well as in the wings of the Gaussian laser beam distribution for higher used fluence. LSFL formation was associated with the material ablation process and accompanied by the intense formation of nanoparticles, especially in the Ni/Ti system. The composition changes at the surface of both multilayer systems in the LSFL area indicated the intermixing between layers and the substrate. Concentration and distribution of all constitutive elements in the irradiated area with formed HSFLs were almost unchanged.

  7. Nanometer-resolved chemical analyses of femtosecond laser-induced periodic surface structures on titanium

    NASA Astrophysics Data System (ADS)

    Kirner, Sabrina V.; Wirth, Thomas; Sturm, Heinz; Krüger, Jörg; Bonse, Jörn

    2017-09-01

    The chemical characteristics of two different types of laser-induced periodic surface structures (LIPSS), so-called high and low spatial frequency LIPSS (HSFL and LSFL), formed upon irradiation of titanium surfaces by multiple femtosecond laser pulses in air (30 fs, 790 nm, 1 kHz), are analyzed by various optical and electron beam based surface analytical techniques, including micro-Raman spectroscopy, energy dispersive X-ray analysis, X-ray photoelectron spectroscopy, and Auger electron spectroscopy. The latter method was employed in a high-resolution mode being capable of spatially resolving even the smallest HSFL structures featuring spatial periods below 100 nm. In combination with an ion sputtering technique, depths-resolved chemical information of superficial oxidation processes was obtained, revealing characteristic differences between the two different types of LIPSS. Our results indicate that a few tens of nanometer shallow HSFL are formed on top of a ˜150 nm thick graded superficial oxide layer without sharp interfaces, consisting of amorphous TiO2 and partially crystallized Ti2O3. The larger LSFL structures with periods close to the irradiation wavelength originate from the laser-interaction with metallic titanium. They are covered by a ˜200 nm thick amorphous oxide layer, which consists mainly of TiO2 (at the surface) and other titanium oxide species of lower oxidation states underneath.

  8. Sub-Diffraction Limited Writing based on Laser Induced Periodic Surface Structures (LIPSS)

    PubMed Central

    He, Xiaolong; Datta, Anurup; Nam, Woongsik; Traverso, Luis M.; Xu, Xianfan

    2016-01-01

    Controlled fabrication of single and multiple nanostructures far below the diffraction limit using a method based on laser induced periodic surface structure (LIPSS) is presented. In typical LIPSS, multiple lines with a certain spatial periodicity, but often not well-aligned, were produced. In this work, well-controlled and aligned nanowires and nanogrooves with widths as small as 40 nm and 60 nm with desired orientation and length are fabricated. Moreover, single nanowire and nanogroove were fabricated based on the same mechanism for forming multiple, periodic structures. Combining numerical modeling and AFM/SEM analyses, it was found these nanostructures were formed through the interference between the incident laser radiation and the surface plasmons, the mechanism for forming LIPSS on a dielectric surface using a high power femtosecond laser. We expect that our method, in particular, the fabrication of single nanowires and nanogrooves could be a promising alternative for fabrication of nanoscale devices due to its simplicity, flexibility, and versatility. PMID:27721428

  9. Sub-Diffraction Limited Writing based on Laser Induced Periodic Surface Structures (LIPSS).

    PubMed

    He, Xiaolong; Datta, Anurup; Nam, Woongsik; Traverso, Luis M; Xu, Xianfan

    2016-10-10

    Controlled fabrication of single and multiple nanostructures far below the diffraction limit using a method based on laser induced periodic surface structure (LIPSS) is presented. In typical LIPSS, multiple lines with a certain spatial periodicity, but often not well-aligned, were produced. In this work, well-controlled and aligned nanowires and nanogrooves with widths as small as 40 nm and 60 nm with desired orientation and length are fabricated. Moreover, single nanowire and nanogroove were fabricated based on the same mechanism for forming multiple, periodic structures. Combining numerical modeling and AFM/SEM analyses, it was found these nanostructures were formed through the interference between the incident laser radiation and the surface plasmons, the mechanism for forming LIPSS on a dielectric surface using a high power femtosecond laser. We expect that our method, in particular, the fabrication of single nanowires and nanogrooves could be a promising alternative for fabrication of nanoscale devices due to its simplicity, flexibility, and versatility.

  10. Sodium periodate-induced human suppressor cells for polyclonal B cell activation.

    PubMed

    Goust, J M

    1982-09-01

    Sodium periodate (SP) induces proliferation of mature T cells. In this study, human peripheral blood mononuclear cells (MNC) pretreated for 10 minutes at room temperature with increasing concentrations (0.1 to 5 mM) of SP before culture for 7 days in the presence of pokeweed mitogen (PWM) exhibited a dose-dependent inhibition of IgG production, contrasting with an increase in 3H-thymidine uptake. When MNC from 70 normal individuals were pretreated with 1 and 2 mM SP, IgG production in culture was suppressed by 46.8 +/- 4.5% and 60.4 +/- 4.4% (mean +/- S.E.M.), respectively, as compared to IgG synthesis in the presence of PWM alone. Longitudinal studies of MNC obtained from the same normal individuals over 6-10 months showed similar degrees of suppression, indicating that the level of SP-inducible suppressor cell activity remains relatively constant, although the degree of suppression varies among normal persons. Both T cells and monocytes were required for PWM-driven IgG production and for SP-induced suppression. A soluble factor elaborated by SP-treated monocytes was also able to suppress IgG production. This model should provide useful information about abnormal regulation of IgG synthesis in various pathological conditions.

  11. Twist1 Is a TNF-Inducible Inhibitor of Clock Mediated Activation of Period Genes.

    PubMed

    Meier, Daniel; Lopez, Martin; Franken, Paul; Fontana, Adriano

    2015-01-01

    Activation of the immune system affects the circadian clock. Tumor necrosis factor (TNF) and Interleukin (IL)-1β inhibit the expression of clock genes including Period (Per) genes and the PAR-bZip clock-controlled gene D-site albumin promoter-binding protein (Dbp). These effects are due to cytokine-induced interference of E-box mediated transcription of clock genes. In the present study we have assessed the two E-box binding transcriptional regulators Twist1 and Twist2 for their role in cytokine induced inhibition of clock genes. The expression of the clock genes Per1, Per2, Per3 and of Dbp was assessed in NIH-3T3 mouse fibroblasts and the mouse hippocampal neuronal cell line HT22. Cells were treated for 4h with TNF and IL-1β. The functional role of Twist1 and Twist2 was assessed by siRNAs against the Twist genes and by overexpression of TWIST proteins. In luciferase (luc) assays NIH-3T3 cells were transfected with reporter gene constructs, which contain a 3xPer1 E-box or a Dbp E-box. Quantitative chromatin immunoprecipitation (ChIP) was performed using antibodies to TWIST1 and CLOCK, and the E-box consensus sequences of Dbp (CATGTG) and Per1 E-box (CACGTG). We report here that siRNA against Twist1 protects NIH-3T3 cells and HT22 cells from down-regulation of Period and Dbp by TNF and IL-1β. Overexpression of Twist1, but not of Twist2, mimics the effect of the cytokines. TNF down-regulates the activation of Per1-3xE-box-luc, the effect being prevented by siRNA against Twist1. Overexpression of Twist1, but not of Twist2, inhibits Per1-3xE-box-luc or Dbp-E-Box-luc activity. ChIP experiments show TWIST1 induction by TNF to compete with CLOCK binding to the E-box of Period genes and Dbp. Twist1 plays a pivotal role in the TNF mediated suppression of E-box dependent transactivation of Period genes and Dbp. Thereby Twist1 may provide a link between the immune system and the circadian timing system.

  12. Laser-induced periodic surface structure in nickel-fullerene composites

    NASA Astrophysics Data System (ADS)

    Vacik, J.; Lavrentiev, V.; Havranek, V.; Horak, P.; Hnatowicz, V.; Fajgar, R.

    2016-02-01

    The phase separation of a thin film of the binary composite of Ni and C60 has been studied using laser illumination of the sample through an array of pinholes (with a diameter of 10-µm and 60-µm × 80-µm spacing). The mesh with pinholes enabled splitting of the probing beam into an array of close-spaced laser micro-beams. The simultaneous illumination of the composite, with a set of micro-beams, resulted in a fast phase separation of the hybrid matter and an occurrence of unusual laser-induced periodic surface structures - a net of complex Ni and C allotropes (C60 and amorphous C) concentric rings and a fine array of the C60 - based islands, regularly distributed over the Ni + C60 thin film matrix. The results confirmed the high proclivity of the hybrid Ni + C60 composites to a correlated separation of the Ni and C-allotrope phases.

  13. Noise induced escape from a nonhyperbolic chaotic attractor of a periodically driven nonlinear oscillator

    NASA Astrophysics Data System (ADS)

    Chen, Zhen; Li, Yang; Liu, Xianbin

    2016-06-01

    Noise induced escape from the domain of attraction of a nonhyperbolic chaotic attractor in a periodically excited nonlinear oscillator is investigated. The general mechanism of the escape in the weak noise limit is studied in the continuous case, and the fluctuational path is obtained by statistical analysis. Selecting the primary homoclinic tangency as the initial condition, the action plot is presented by parametrizing the set of escape trajectories and the global minimum gives rise to the optimal path. Results of both methods show good agreements. The entire process of escape is discussed in detail step by step using the fluctuational force. A structure of hierarchical heteroclinic crossings of stable and unstable manifolds of saddle cycles is found, and the escape is observed to take place through successive jumps through this deterministic hierarchical structure.

  14. Investigation of the writing mechanism of electric-arc-induced long-period fiber gratings.

    PubMed

    Malki, Abdelrafik; Humbert, Georges; Ouerdane, Youcef; Boukhenter, Aziz; Boudrioua, Azzedine

    2003-07-01

    The mechanism for inscription of electric-arc-induced long-period gratings in SMF28 fiber was studied. The refractive-index profiles of irradiated fiber samples were measured, and their structures were investigated by Raman and luminescence spectroscopy. Slight geometrical deformations of the irradiated fiber were measured. A significant change in the Raman spectrum range from 200 to 700 cm(-1) caused by the electric arc is reported. The results show a decrease in the intensity of this band, indicating a modification, such as densification, of the glass structure. No modification of the fictive temperature was measured. A large increase in the red luminescence band was also observed and attests to the creation of defects in the fiber network structure.

  15. Noise induced transitions and topological study of a periodically driven system

    NASA Astrophysics Data System (ADS)

    Chen, Zhen; Liu, Xianbin

    2017-07-01

    Noise induced transitions of an overdamped periodically driven oscillator are investigated theoretically and numerically in the limit of weak noise due to the Freidlin-Wentzell large deviation theory. Heteroclinic trajectories are found to approach the unstable orbit with fluctuational force tending to zeros. The global minimizer of the action functional corresponds to the most probable escape path and it shows a good agreement with statistical results. We then study the origins of singularities from a topological point of view by considering structures of the Lagrangian manifold and action surface. The switching line and cusp point turn out to have physical significance since they may impact the prehistory distributions, making the optimal path invalid.

  16. Noise induced escape from a nonhyperbolic chaotic attractor of a periodically driven nonlinear oscillator

    SciTech Connect

    Chen, Zhen E-mail: xbliu@nuaa.edu.cn; Li, Yang; Liu, Xianbin E-mail: xbliu@nuaa.edu.cn

    2016-06-15

    Noise induced escape from the domain of attraction of a nonhyperbolic chaotic attractor in a periodically excited nonlinear oscillator is investigated. The general mechanism of the escape in the weak noise limit is studied in the continuous case, and the fluctuational path is obtained by statistical analysis. Selecting the primary homoclinic tangency as the initial condition, the action plot is presented by parametrizing the set of escape trajectories and the global minimum gives rise to the optimal path. Results of both methods show good agreements. The entire process of escape is discussed in detail step by step using the fluctuational force. A structure of hierarchical heteroclinic crossings of stable and unstable manifolds of saddle cycles is found, and the escape is observed to take place through successive jumps through this deterministic hierarchical structure.

  17. Experimental study of fs-laser induced sub-100-nm periodic surface structures on titanium.

    PubMed

    Nathala, Chandra S R; Ajami, Ali; Ionin, Andrey A; Kudryashov, Sergey I; Makarov, Sergey V; Ganz, Thomas; Assion, Andreas; Husinsky, Wolfgang

    2015-03-09

    In this work the formation of laser-induced periodic surface structures (LIPSS) on a titanium surface upon irradiation by linearly polarized femtosecond (fs) laser pulses with a repetition rate of 1 kHz in air environment was studied experimentally. In particular, the dependence of high-spatial-frequency-LIPSS (HSFL) characteristics on various laser parameters: fluence, pulse number, wavelength (800 nm and 400 nm), pulse duration (10 fs - 550 fs), and polarization was studied in detail. In comparison with low-spatial-frequency-LIPSS (LSFL), the HSFL emerge at a much lower fluence with orientation perpendicular to the ridges of the LSFL. It was observed that these two types of LIPSS demonstrate different fluence, shot number and wavelength dependencies, which suggest their origin is different. Therefore, the HSFL formation mechanism cannot be described by the widely accepted interference model developed for describing LSFL formation.

  18. Noise induced escape from a nonhyperbolic chaotic attractor of a periodically driven nonlinear oscillator.

    PubMed

    Chen, Zhen; Li, Yang; Liu, Xianbin

    2016-06-01

    Noise induced escape from the domain of attraction of a nonhyperbolic chaotic attractor in a periodically excited nonlinear oscillator is investigated. The general mechanism of the escape in the weak noise limit is studied in the continuous case, and the fluctuational path is obtained by statistical analysis. Selecting the primary homoclinic tangency as the initial condition, the action plot is presented by parametrizing the set of escape trajectories and the global minimum gives rise to the optimal path. Results of both methods show good agreements. The entire process of escape is discussed in detail step by step using the fluctuational force. A structure of hierarchical heteroclinic crossings of stable and unstable manifolds of saddle cycles is found, and the escape is observed to take place through successive jumps through this deterministic hierarchical structure.

  19. Temperature sensing on tapered single mode fiber using mechanically induced long period fiber gratings

    NASA Astrophysics Data System (ADS)

    Marrujo-García, Sigifredo; Velázquez-González, Jesús Salvador; Pulido-Navarro, María. Guadalupe; González-Ocaña, Ernesto; Mújica-Ascencio, Saúl; Martínez-Piñón, Fernando

    2015-09-01

    The modeling of a temperature optical fiber sensor is proposed and experimentally demonstrated in this work. The suggested structure to obtain the sensing temperature characteristics is by the use of a mechanically induced Long Period Fiber Grating (LPFG) on a tapered single mode optical fiber. A biconical fiber optic taper is made by applying heat using an oxygen-propane flame burner while stretching the single mode fiber (SMF) whose coating has been removed. The resulting geometry of the device is important to analyze the coupling between the core mode to the cladding modes, and this will determine whether the optical taper is adiabatic or non-adiabatic. On the other hand, the mechanical LPFG is made up of two plates, one grooved and other flat, the grooved plate was done on an acrylic slab with the help of a computerized numerical control machine (CNC). In addition to the experimental work, the supporting theory is also included.

  20. Melanopsin resets circadian rhythms in cells by inducing clock gene Period1

    NASA Astrophysics Data System (ADS)

    Yamashita, Shuhei; Uehara, Tomoe; Matsuo, Minako; Kikuchi, Yo; Numano, Rika

    2014-02-01

    The biochemical, physiological and behavioral processes are under the control of internal clocks with the period of approximately 24 hr, circadian rhythms. The expression of clock gene Period1 (Per1) oscillates autonomously in cells and is induced immediately after a light pulse. Per1 is an indispensable member of the central clock system to maintain the autonomous oscillator and synchronize environmental light cycle. Per1 expression could be detected by Per1∷luc and Per1∷GFP plasmid DNA in which firefly luciferase and Green Fluorescence Protein were rhythmically expressed under the control of the mouse Per1 promoter in order to monitor mammalian circadian rhythms. Membrane protein, MELANOPSIN is activated by blue light in the morning on the retina and lead to signals transduction to induce Per1 expression and to reset the phase of circadian rhythms. In this report Per1 induction was measured by reporter signal assay in Per1∷luc and Per1∷GFP fibroblast cell at the input process of circadian rhythms. To the result all process to reset the rhythms by Melanopsin is completed in single cell like in the retina projected to the central clock in the brain. Moreover, the phase of circadian rhythm in Per1∷luc cells is synchronized by photo-activated Melanopsin, because the definite peak of luciferase activity in one dish was found one day after light illumination. That is an available means that physiological circadian rhythms could be real-time monitor as calculable reporter (bioluminescent and fluorescent) chronological signal in both single and groups of cells.

  1. Long-period tilt-induced accelerations associated with hydraulic fracturing

    NASA Astrophysics Data System (ADS)

    Milkereit, Claus; Dahm, Torsten; Cesca, Simone; Lopez, Jose; Nooshiri, Nima; Zang, Arno

    2017-04-01

    In 2015, several small scale hydrofracture experiments have been performed in situ from a horizontal borehole in a mine gallery in granitic rock. The hydrofracture experiments were monitored by a bundle of different near field sensors covering a broad range of frequencies (see Zang et al., Geophys. J. Int. (2017) 208, 790-813, doi: 10.1093/gji/ggw430). We installed broad band sensors in the gallery close to the fracture experiments, and observed clear long period transients on the horizontal components, with timing and polarity correlated with the opening and closing of the fractures. We interpret the broadband signals as tilt-induced excursions. The broadband signals have been measured independent whether high frequency acoustic emission have been observed or not during the individual fracture experiments. They are thus an independent measure of the success of a hydrofracture experiment and the parameter of the newly formed cracks. In this study we show that most tilt-induced long-period signals can be modeled by a rectangular crack with constant opening in an elastic full space, as first order approximation. From theoretical forward modeling, we proof that the tilt has a higher sensitivity to resolve the strike of the fracture than the displacement field. With this model, we retrieve the strike of the fractures from the tilt observed at a single sensor. The results indicate that the strike angles of the hydrofractures change systematically with the distance to the gallery wall, indicating a rotation of the principal stresses close to the free surface of the gallery. The rotation trend is similar to the one observed in previous hydrofracture experiments in mines. We compare the strength of the modeled tensile cracks, i.e. opening times crack area, with the volume of the injected fluid, and discuss the general resolving power of tilt signals for source parameter fractures. The temporal evolution of the opening and closure of the fractures is discussed.

  2. Femtosecond laser-induced periodic surface structures on titanium nitride coatings for tribological applications

    NASA Astrophysics Data System (ADS)

    Bonse, J.; Kirner, S. V.; Koter, R.; Pentzien, S.; Spaltmann, D.; Krüger, J.

    2017-10-01

    Titanium nitride (TiN) was coated on different substrate materials, namely pure titanium (Ti), titanium alloy (Ti6Al4V) and steel (100Cr6), generating 2.5 μm thick TiN layers. Using femtosecond laser pulses (30 fs, 790 nm, 1 kHz pulse repetition rate), large surface areas (5 mm × 5 mm) of laser-induced periodic surface structures (LIPSS) with sub-wavelength periods ranging between 470 nm and 600 nm were generated and characterized by optical microscopy (OM), white light interference microscopy (WLIM) and scanning electron microscopy (SEM). In tribological tests, coefficients of friction (COF) of the nanostructured surfaces were determined under reciprocating sliding conditions (1 Hz, 1.0 N normal load) against a 10-mm diameter ball of hardened 100Cr6 steel during 1000 cycles using two different lubricants, namely paraffin oil and engine oil. It turned out that the substrate material, the laser fluence and the lubricant are crucial for the tribological performance. However, friction and wear could not be significantly reduced by LIPSS on TiN layers in comparison to unstructured TiN surfaces. Finally, the resulting wear tracks on the nanostructured surfaces were investigated with respect to their morphology (OM, SEM), depth (WLIM) and chemical composition by energy dispersive X-ray spectroscopy (EDX) and, on one hand, compared with each other, on the other hand, with non-structured TiN surfaces.

  3. Femtosecond laser-induced periodic surface structures on steel and titanium alloy for tribological applications

    NASA Astrophysics Data System (ADS)

    Bonse, J.; Koter, R.; Hartelt, M.; Spaltmann, D.; Pentzien, S.; Höhm, S.; Rosenfeld, A.; Krüger, J.

    2014-10-01

    Laser-induced periodic surface structures (LIPSS, ripples) were generated on stainless steel (100Cr6) and titanium alloy (Ti6Al4V) surfaces upon irradiation with multiple femtosecond laser pulses (pulse duration 30 fs, central wavelength 790 nm). The experimental conditions (laser fluence, spatial spot overlap) were optimized in a sample-scanning geometry for the processing of large surface areas (5 × 5 mm2) covered homogeneously by the nanostructures. The irradiated surface regions were subjected to white light interference microscopy and scanning electron microscopy revealing spatial periods around 600 nm. The tribological performance of the nanostructured surface was characterized by reciprocal sliding against a ball of hardened steel in paraffin oil and in commercial engine oil as lubricants, followed by subsequent inspection of the wear tracks. For specific conditions, on the titanium alloy a significant reduction of the friction coefficient by a factor of more than two was observed on the laser-irradiated (LIPSS-covered) surface when compared to the non-irradiated one, indicating the potential benefit of laser surface structuring for tribological applications.

  4. Assessment of femtosecond laser induced periodic surface structures on polymer films.

    PubMed

    Rebollar, Esther; Vázquez de Aldana, Javier R; Martín-Fabiani, Ignacio; Hernández, Margarita; Rueda, Daniel R; Ezquerra, Tiberio A; Domingo, Concepción; Moreno, Pablo; Castillejo, Marta

    2013-07-21

    In this work we present the formation of laser induced periodic surface structures (LIPSS) on spin-coated thin films of several model aromatic polymers including poly(ethylene terephthalate), poly(trimethylene terephthalate) and poly carbonate bis-phenol A upon irradiation with femtosecond pulses of 795 and 265 nm at fluences well below the ablation threshold. LIPSS are formed with period lengths similar to the laser wavelength and parallel to the direction of the laser polarization vector. Formation of LIPSS upon IR irradiation at 795 nm, a wavelength at which the polymers absorb weakly, contrasts with the absence of LIPSS in this spectral range upon irradiation with nanosecond pulses. Real and reciprocal space characterization of LIPSS obtained by Atomic Force Microscopy (AFM) and Grazing Incidence Small Angle X-ray Scattering (GISAXS), respectively, yields well correlated morphological information. Comparison of experimental and simulated GISAXS patterns suggests that LIPSS can be suitably described considering a quasi-one-dimensional paracrystalline lattice and that irradiation parameters have an influence on the order of such a lattice. Fluorescence measurements, after laser irradiation, provide indirect information about dynamics and structure of the polymer at the molecular level. Our results indicate that the LIPSS are formed by interference of the incident and surface scattered waves. As a result of this process, heating of the polymer surface above its glass transition temperature takes place enabling LIPSS formation.

  5. Influence of substrate microcrystallinity on the orientation of laser-induced periodic surface structures

    SciTech Connect

    Nürnberger, P.; Reinhardt, H.; Kim, H-C.; Yang, F.; Peppler, K.; Janek, J.; Hampp, N.

    2015-10-07

    The research in this paper deals with the angular dependence of the formation of laser-induced periodic surface structures (LIPSS) by linearly polarized nanosecond laser pulses on polycrystalline austenitic stainless steel. Incident angles ranging from 45° to 70° lead to the generation of superimposed merely perpendicular oriented LIPSS on steel as well as on monocrystalline (100) silicon which was used as a reference material. Additional extraordinary orientations of superimposing LIPSS along with significantly different periodicities are found on polycrystalline steel but not on (100) silicon. Electron backscatter diffraction measurements indicate that the expansion of these LIPSS is limited to the grain size and affected by the crystal orientation of the individual grains. Atomic force microscopy imaging shows that LIPSS fringe heights are in good agreement with the theoretically predicted penetration depths of surface plasmon polaritons into stainless steel. These results indicate that optical anisotropies must be taken into account to fully describe the theory of light-matter interaction leading to LIPSS formation.

  6. Multiple coherence resonance induced by time-periodic coupling in stochastic Hodgkin-Huxley neuronal networks

    NASA Astrophysics Data System (ADS)

    Lin, Xiu; Gong, Yubing; Wang, Li

    2011-12-01

    In this paper, we study the effect of time-periodic coupling strength (TPCS) on the spiking coherence of Newman-Watts small-world networks of stochastic Hodgkin-Huxley (HH) neurons and investigate the relations between the coupling strength and channel noise when coherence resonance (CR) occurs. It is found that, when the amplitude of TPCS is varied, the spiking induced by channel noise can exhibit CR and coherence bi-resonance (CBR), and the CR moves to a smaller patch area (bigger channel noise) when the amplitude increases; when the frequency of TPCS is varied, the intrinsic spiking can exhibit CBR and multiple CR, and the CR always occurs when the frequency is equal to or multiple of the spiking period, manifesting as the locking between the frequencies of the intrinsic spiking and the coupling strength. These results show that TPCS can greatly enhance and optimize the intrinsic spiking coherence, and favors the spiking with bigger channel noise to exhibit CR. This implies that, compared to constant coupling strength, TPCS may play a more efficient role for improving the time precision of the information processing in stochastic neuronal networks.

  7. Reversal of peripheral nerve injury-induced hypersensitivity in the postpartum period: role of spinal oxytocin.

    PubMed

    Gutierrez, Silvia; Liu, Baogang; Hayashida, Ken-ichiro; Houle, Timothy T; Eisenach, James C

    2013-01-01

    Physical injury, including surgery, can result in chronic pain; yet chronic pain following childbirth, including cesarean delivery in women, is rare. The mechanisms involved in this protection by pregnancy or delivery have not been explored. We examined the effect of pregnancy and delivery on hypersensitivity to mechanical stimuli of the rat hindpaw induced by peripheral nerve injury (spinal nerve ligation) and after intrathecal oxytocin, atosiban, and naloxone. Additionally, oxytocin concentration in lumbar spinal cerebrospinal fluid was determined. Spinal nerve ligation performed at mid-pregnancy resulted in similar hypersensitivity to nonpregnant controls, but hypersensitivity partially resolved beginning after delivery. Removal of pups after delivery prevented this partial resolution. Cerebrospinal fluid concentrations of oxytocin were greater in normal postpartum rats prior to weaning. To examine the effect of injury at the time of delivery rather than during pregnancy, spinal nerve ligation was performed within 24 h of delivery. This resulted in acute hypersensitivity that partially resolved over the next 2-3 weeks. Weaning of pups resulted only in a temporary return of hypersensitivity. Intrathecal oxytocin effectively reversed the hypersensitivity following separation of the pups. Postpartum resolution of hypersensitivity was transiently abolished by intrathecal injection of the oxytocin receptor antagonist, atosiban. These results suggest that the postpartum period rather than pregnancy protects against chronic hypersensitivity from peripheral nerve injury and that this protection may reflect sustained oxytocin signaling in the central nervous system during this period.

  8. Formation and Properties of Laser-Induced Periodic Surface Structures on Different Glasses.

    PubMed

    Gräf, Stephan; Kunz, Clemens; Müller, Frank A

    2017-08-10

    The formation and properties of laser-induced periodic surface structures (LIPSS) was investigated on different technically relevant glasses including fused silica, borosilicate glass, and soda-lime-silicate glass under irradiation of fs-laser pulses characterized by a pulse duration τ = 300 fs and a laser wavelength λ = 1025 nm. For this purpose, LIPSS were fabricated in an air environment at normal incidence with different laser peak fluence, pulse number, and repetition frequency. The generated structures were characterized by using optical microscopy, scanning electron microscopy, focused ion beam preparation and Fast-Fourier transformation. The results reveal the formation of LIPSS on all investigated glasses. LIPSS formation on soda-lime-silicate glass is determined by remarkable melt-formation as an intra-pulse effect. Differences between the different glasses concerning the appearing structures, their spatial period and their morphology were discussed based on the non-linear absorption behavior and the temperature-dependent viscosity. The findings facilitate the fabrication of tailored LIPSS-based surface structures on different technically relevant glasses that could be of particular interest for various applications.

  9. Multiple coherence resonance induced by time-periodic coupling in stochastic Hodgkin-Huxley neuronal networks.

    PubMed

    Lin, Xiu; Gong, Yubing; Wang, Li

    2011-12-01

    In this paper, we study the effect of time-periodic coupling strength (TPCS) on the spiking coherence of Newman-Watts small-world networks of stochastic Hodgkin-Huxley (HH) neurons and investigate the relations between the coupling strength and channel noise when coherence resonance (CR) occurs. It is found that, when the amplitude of TPCS is varied, the spiking induced by channel noise can exhibit CR and coherence bi-resonance (CBR), and the CR moves to a smaller patch area (bigger channel noise) when the amplitude increases; when the frequency of TPCS is varied, the intrinsic spiking can exhibit CBR and multiple CR, and the CR always occurs when the frequency is equal to or multiple of the spiking period, manifesting as the locking between the frequencies of the intrinsic spiking and the coupling strength. These results show that TPCS can greatly enhance and optimize the intrinsic spiking coherence, and favors the spiking with bigger channel noise to exhibit CR. This implies that, compared to constant coupling strength, TPCS may play a more efficient role for improving the time precision of the information processing in stochastic neuronal networks.

  10. Defect-induced period-doubling perturbation on Si(111)4x1-In

    NASA Astrophysics Data System (ADS)

    Lee, Geunseop; Yu, Sang-Yong

    2005-03-01

    We investigated using STM and LEED the influence of defects at room temperature on the quasi-one dimensional Si(111)4x1-In surface which changes into a 4x2 (or 8x2) phase below 120 K. Various types of defects (vacancy, step edge, and phase shift boundary) and adatoms (H2, O2, and In) were found to induce local period-doubling (x2) modulations at room temperature. The x2 modulated region shows metallic I-V characteristics, having little change from that of the defect-free 4x1 region despite the difference in topology in the image. Therefore, the defect-induced x2 modulation is discriminated from the low-temperature phase that was reported to be insulating. Using the first-principles calculations, the x2 modulation is found to originate from a different 4x2 structure of the clean surface that is stabilized by the presence of defects. The nature of the phase transition of this In/Si(111) system and the influence of the defects will be discussed.

  11. Superhydrophobic and colorful copper surfaces fabricated by picosecond laser induced periodic nanostructures

    NASA Astrophysics Data System (ADS)

    Long, Jiangyou; Fan, Peixun; Zhong, Minlin; Zhang, Hongjun; Xie, Yongde; Lin, Chen

    2014-08-01

    In this study, functional copper surfaces combined with vivid structural colors and superhydrophobicity were fabricated by picosecond laser. Laser-induced periodic surface structures (LIPSS), i.e. ripples, were fabricated by picosecond laser nanostructuring to induce rainbow-like structural colors which are uniquely caused by the grating - type structure. The effects of laser processing parameters on the formation of ripples were investigated. We also discussed the formation mechanism of ripples. With different combinations of the laser processing parameters, ripples with various morphologies were fabricated. After the modification with triethoxyoctylsilane, different types of ripples exhibited different levels of wettability. The fine ripples with minimal redeposited nanoparticles exhibited high adhesive force to water. The increased amount of nanoscale structures decreased the adhesive force to water and increased the contact angle simultaneously. In particular, a specific type of ripples exhibited superhydrophobicity with a large contact angle of 153.9 ± 3.2° and a low sliding angle of 11 ± 3°.

  12. Commensurability Oscillations of Composite Fermions Induced by the Periodic Potential of a Wigner Crystal

    NASA Astrophysics Data System (ADS)

    Deng, H.; Liu, Y.; Jo, I.; Pfeiffer, L. N.; West, K. W.; Baldwin, K. W.; Shayegan, M.

    2016-08-01

    When the kinetic energy of a collection of interacting two-dimensional (2D) electrons is quenched at very high magnetic fields so that the Coulomb repulsion dominates, the electrons are expected to condense into an ordered array, forming a quantum Wigner crystal (WC). Although this exotic state has long been suspected in high-mobility 2D electron systems at very low Landau level fillings (ν ≪1 ), its direct observation has been elusive. Here we present a new technique and experimental results directly probing the magnetic-field-induced WC. We measure the magnetoresistance of a bilayer electron system where one layer has a very low density and is in the WC regime (ν ≪1 ), while the other ("probe") layer is near ν =1 /2 and hosts a sea of composite fermions (CFs). The data exhibit commensurability oscillations in the magnetoresistance of the CF layer, induced by the periodic potential of WC electrons in the other layer, and provide a unique, direct glimpse at the symmetry of the WC, its lattice constant, and melting. They also demonstrate a striking example of how one can probe an exotic many-body state of 2D electrons using equally exotic quasiparticles of another many-body state.

  13. Ms. No.: NSC-12-1582: Periadolescent ethanol vapor exposure persistently reduces measures of hippocampal neurogenesis that are associated with behavioral outcomes in adulthood

    PubMed Central

    Ehlers, Cindy L.; Liu, Wen; Wills, Derek N.; Crews, Fulton T.

    2013-01-01

    animals that were sacrificed at 114 days. The reduction seen in DCX labeled in cell counts was significantly correlated with hypoactivity at 24 hours after withdrawal as well as less anxiety-like and/or more “disinhibitory” behavior in the open field conflict test at 2 and 8 weeks following termination of vapor exposure. These studies demonstrate that behavioral measures of disinhibitory behavior correlated with decreases in neurogenesis are all significantly and persistently impacted by periadolescent ethanol exposure and withdrawal in Wistar rats. PMID:23567812

  14. Behavioral and growth effects induced by low dose methamphetamine administration during the neonatal period in rats.

    PubMed

    Williams, Michael T; Moran, Mary S; Vorhees, Charles V

    2004-01-01

    The investigation of methamphetamine exposure during neonatal development in rats has demonstrated that long-term spatial learning deficits are induced. A previous dose-response study showed that administration of 5 mg/kg methamphetamine, four times daily from postnatal days 11 to 20 produced these deficits, although the effects were not as severe as at higher doses of 10 or 15 mg/kg. This study examined concentrations of methamphetamine at or below 5mg/kg given over the same period of time. Five different concentrations of methamphetamine (i.e., 5, 2.5, 1.25, 0.625, or 0) were administered every 2 h four times daily from postnatal days 11 to 20. Body weights, zero maze performance, and Morris water maze learning were examined. A dose-dependent decrease in body weight was observed during the period of methamphetamine administration and these lower weights continued throughout adulthood for the 5, 2.5, and 1.25 mg/kg concentrations, although the adult decreases were negligible. No differences were noted in the zero maze. In the Morris water maze during the acquisition period, dose-dependent differences in spatial orientation were seen, however non-dose related deficits were observed for other parameters. During the shifted platform phase ("reversal"), a similar dose-dependent difference in spatial orientation was observed, although no other effects were noted during this phase. Females performed worse than males regardless of treatment or the phase of learning in the Morris water maze. These data suggest that even lower doses of methamphetamine can alter learning and memory in adulthood, although with less consistent results than with doses higher than 5 mg/kg/dose. These data would caution against even casual use of methamphetamine by women during pregnancy since even low doses could alter the ability of the child to learn.

  15. Investigating the recovery period of rat brain tissue after electrolytic and 980-nm laser induced lesions

    NASA Astrophysics Data System (ADS)

    Bozkulak, Ozguncem; Tabakoglu, H. Ozgur; Aksoy, Ayla; Canbeyli, Resit; Bilgin, Nes'e.; Kurtkaya, Ozlem; Sav, Aydin; Gulsoy, Murat

    2003-10-01

    The effects of 980-nm diode laser and electrolytic lesions in Wistar rat brain tissue were observed by immunohistochemical staining for CD68 marker and Hematoxylin-Eosin (H&E). Bilateral lesions; laser lesions (2W/2sec) in the right hemispheres, and electrolytic lesions (1.5mA/20sec) in the left hemispheres were done through in vivo stereotaxic neurosurgical procedure. Subjects were classified into three groups due to the recovery period. Subjects in Group I, II, and III were sacrificed after 0, 2 and 7 days of recovery period respectively. After saline perfusion their brains were dislocated, and paraffin embedded sections were taken. One section for H&E and one for CD68 were cut consecutively in 3μm thickness by examining the lesion in every 30-μm thickness. CD68 was found more efficient marker than H&E in observing the after-effects of both types of lesions. The total damage of laser was smaller than that of electrosurgical unit. The shape of the ablated area in laser induced lesions was more spherical than that of electrosurgical unit. The number of macrophages increased as the recovery period increased for all subjects. Group III showed the highest number of macrophages in three, and the number of macrophages around electrolytic lesion is nearly 1.5 times higher than that of laser lesion. The remarkable ablating ability, the damage zone created and the healing of nearby tissue clearly showed that the 980-nm diode laser is an effective and useful alternative to electrosurgical unit in neurosurgery.

  16. Evidence of liquid phase during laser-induced periodic surface structures formation induced by accumulative ultraviolet picosecond laser beam

    SciTech Connect

    Huynh, T. T. D.; Petit, A.; Semmar, N.

    2015-11-09

    Laser-induced periodic surface structures (LIPSS) were formed on Cu/Si or Cu/glass thin films using Nd:YAG laser beam (40 ps, 10 Hz, and 30 mJ/cm{sup 2}). The study of ablation threshold is always achieved over melting when the variation of the number of pulses increases from 1 to 1000. But the incubation effect is leading to reduce the threshold of melting as increasing the number of laser pulse. Also, real time reflectivity signals exhibit typical behavior to stress the formation of a liquid phase during the laser-processing regime and helps to determine the threshold of soft ablation. Atomic Force Microscopy (AFM) analyses have shown the topology of the micro-crater containing regular spikes with different height. Transmission Electron Microscopy (TEM) allows finally to show three distinguished zones in the close region of isolated protrusions. The central zone is a typical crystallized area of few nanometers surrounded by a mixed poly-crystalline and amorphous area. Finally, in the region far from the protrusion zone, Cu film shows an amorphous structure. The real time reflectivity, AFM, and HR-TEM analyses evidence the formation of a liquid phase during the LIPSS formation in the picosecond regime.

  17. Radio Induced Fluorescence (RIF) Imaging Of E-region Quasi-periodic Structures

    NASA Astrophysics Data System (ADS)

    Bernhardt, P. A.

    The horizontal structure of sporadic-E layers has been imaged using artificial airglow excited by high power radio waves. In January 1998, the HF facility at Arecibo, Puerto Rico beamed a 80 MW signal upward at 3.175 MHz. The beam reflected in the E- region near 120 km altitude to excite green-line emissions at 557.7 nm. Ground based images showed quasi-periodic structures with periods near 2 and 10 km. These struc- tures been interpreted as being produced by Kelvin-Helmholtz (K-H) instabilities in the neutral atmosphere. The excitation of radio induced fluorescence (RIF) emissions has been studied with both one-dimensional and two-dimensional computer simulations of the conversion of electromagnetic waves into electron plasma waves. The steep gradients on the bottomside of the E-layer provide conditions for efficient mode conversion. The re- sulting Langmuir waves accelerate electrons to energies between 2 and 10 eV. These suprathermal electrons collide with oxygen atoms to produce green-line emissions. The optical glow only occurs in the parts of the E-region where the plamsa is dense enough to reflect the 3.175 MHz radio waves. Results of the E-layer observations using the RIF technique have shown horizontal stuctures that are most likely produced by the K-H instability. A numerical model has been generated to demonstrate the effects of neutral wind shears on the E-region structures. The model includes the effects of both speed-shear and turning shear dy- namics. The results of the numerical model are used to suggest future research using high-power radio wave to study the ion dynamics of the lower thermosphere.

  18. Heart period and blood pressure characteristics in splanchnic arterial occlusion shock-induced collapse.

    PubMed

    Aletti, Federico; Gambarotta, Nicolò; Penn, Alexander H; Ferrario, Manuela; Schmid-Schönbein, Geert W

    2017-02-01

    The nature of hemodynamic instability typical of circulatory shock is not well understood, but an improved interpretation of its dynamic features could help in the management of critically ill patients. The objective of this work was to introduce new metrics for the analysis of arterial blood pressure (ABP) in order to characterize the risk of catastrophic outcome in splanchnic arterial occlusion (SAO) shock. Continuous ABP (fs = 1 kHz) was measured in rats during experimental SAO shock, which induced a fatal pressure drop (FPD) in ABP. The FPD could either be slow (SFPD) or fast (FFPD), with the latter causing cardiovascular collapse. Time series of mean arterial pressure, systolic blood pressure and heart period were derived from ABP. The sample asymmetry-based algorithm Heart Rate Characteristics was adapted to compute the Heart Period Characteristics (HPC) and the Blood Pressure Characteristics (BPC). Baroreflex sensitivity (BRS) was assessed by means of a bivariate model. The approach to FPD of the animals who collapsed (FFPD) was characterized by higher BRS in the low frequency band versus SFPD animals (0.36 ± 0.15 vs. 0.19 ± 0.12 ms/mmHg, p value = 0.0196), bradycardia as indicated by the HPC (0.76 ± 0.57 vs. 1.94 ± 1.27, p value = 0.0179) and higher but unstable blood pressure as indicated by BPC (3.02 ± 2.87 vs. 1.47 ± 1.29, p value = 0.0773). The HPC and BPC indices demonstrated promise as potential clinical markers of hemodynamic instability and impending cardiovascular collapse, and this animal study suggests their test in data from intensive care patients.

  19. Very long period conduit oscillations induced by rockfalls at Kilauea Volcano, Hawaii

    NASA Astrophysics Data System (ADS)

    Chouet, Bernard; Dawson, Phillip

    2013-10-01

    Eruptive activity at the summit of Kilauea Volcano, Hawaii, beginning in 2010 and continuing to the present time is characterized by transient outgassing bursts accompanied by very long period (VLP) seismic signals triggered by rockfalls from the vent walls impacting a lava lake in a pit within the Halemaumau pit crater. We use raw data recorded with an 11-station broadband network to model the source mechanism of signals accompanying two large rockfalls on 29 August 2012 and two smaller average rockfalls obtained by stacking over all events with similar waveforms to improve the signal-to-noise ratio. To determine the source centroid location and source mechanism, we minimize the residual error between data and synthetics calculated by the finite difference method for a point source embedded in a homogeneous medium that takes topography into account. We apply a new waveform inversion method that accounts for the contributions from both translation and tilt in horizontal seismograms through the use of Green's functions representing the seismometer response to translation and tilt ground motions. This method enables a robust description of the source mechanism over the period range 1-1000 s. The VLP signals associated with the rockfalls originate in a source region ˜1 km below the eastern perimeter of the Halemaumau pit crater. The observed waveforms are well explained by a simple volumetric source with geometry composed of two intersecting cracks including an east striking crack (dike) dipping 80° to the north, intersecting a north striking crack (another dike) dipping 65° to the east. Each rockfall is marked by a similar step-like inflation trailed by decaying oscillations of the volumetric source, attributed to the efficient coupling at the source centroid location of the pressure and momentum changes induced by the rock mass impacting the top of the lava column. Assuming a simple lumped parameter representation of the shallow magmatic system, the observed

  20. Tribological performance of sub-100-nm femtosecond laser-induced periodic surface structures on titanium

    NASA Astrophysics Data System (ADS)

    Bonse, J.; Höhm, S.; Koter, R.; Hartelt, M.; Spaltmann, D.; Pentzien, S.; Rosenfeld, A.; Krüger, J.

    2016-06-01

    Sub-100-nm laser-induced periodic surface structures (LIPSS) were processed on bulk titanium (Ti) surfaces by femtosecond laser pulse irradiation in air (30 fs pulse duration, 790 nm wavelength). The laser peak fluence, the spatial spot overlap, and the number of overscans were optimized in a sample-scanning geometry in order to obtain large surface areas (5 mm × 5 mm) covered homogeneously by the LIPSS. The laser-processed regions were characterized by optical microscopy (OM), white light interference microscopy (WLIM) and scanning electron microscopy (SEM). The friction coefficient of the nanostructured surfaces was tested during 1000 cycles under reciprocal sliding conditions (1 Hz, 1.0 N normal load) against a 10-mm diameter ball of hardened 100Cr6 steel, both in paraffin oil and in engine oil used as lubricants. Subsequently, the corresponding wear tracks were qualified by OM, SEM, and energy dispersive X-ray analyses (EDX). The results of the tribological tests are discussed and compared to that obtained for near wavelength-sized fs-LIPSS, processed under somewhat different irradiation conditions. Some constraints for a beneficial effect of LIPSS on the tribological performance are provided.

  1. Aerobic Interval Exercise Training Induces Greater Reduction in Cardiac Workload in the Recovery Period in Rats

    PubMed Central

    Borges, Juliana Pereira; Masson, Gustavo Santos; Tibiriçá, Eduardo; Lessa, Marcos Adriano

    2014-01-01

    Background Aerobic interval exercise training has greater benefits on cardiovascular function as compared with aerobic continuous exercise training. Objective The present study aimed at analyzing the effects of both exercise modalities on acute and subacute hemodynamic responses of healthy rats. Methods Thirty male rats were randomly assigned into three groups as follows: continuous exercise (CE, n = 10); interval exercise (IE, n = 10); and control (C, n = 10). Both IE and CE groups performed a 30-minute exercise session. The IE group session consisted of three successive 4-minute periods at 60% of maximal velocity (Max Vel), with 4-minute recovery intervals at 40% of Max Vel. The CE group ran continuously at 50% of Max Vel. Heart rate (HR), blood pressure(BP), and rate pressure product (RPP) were measured before, during and after the exercise session. Results The CE and IE groups showed an increase in systolic BP and RPP during exercise as compared with the baseline values. After the end of exercise, the CE group showed a lower response of systolic BP and RPP as compared with the baseline values, while the IE group showed lower systolic BP and mean BP values. However, only the IE group had a lower response of HR and RPP during recovery. Conclusion In healthy rats, one interval exercise session, as compared with continuous exercise, induced similar hemodynamic responses during exercise. However, during recovery, the interval exercise caused greater reductions in cardiac workload than the continuous exercise. PMID:24270864

  2. TEM investigation of laser-induced periodic surface structures on polymer surfaces

    NASA Astrophysics Data System (ADS)

    Prendergast, Úna; Kudzma, Sylwester; Sherlock, Richard; O'Connell, Claire; Glynn, Thomas

    2007-02-01

    Laser Induced Periodic Surface Structures (LIPSS) may have numerous applications, ranging from biomaterial applications to LCDs, microelectronic fabrication and photonics. However, in order to control the development of these structures for their particular application, it is necessary to understand how they are generated. We report our work on investigating the melting that occurs during LIPSS formation. LIPSS were generated on three polymer surfaces - polyethylene terephthalate (PET), amorphous polycarbonate (APC) and oriented crystalline polycarbonate (OPC) - which were irradiated with a polarized ArF excimer laser (193 nm) beam with fluences between 3 and 5 mJ/cm2. The structures were imaged using a Transmission Electron Microscope (TEM), which facilitated investigation of changes in the polymer structures and consequently the depth of the melt zone that accompanies LIPSS generation. We also present theoretical calculations of the temperature-depth profile due to the interaction of the low fluence 193 nm laser beam with the polymer surfaces and compare these calculations with our experimental results.

  3. Fabrication of arc-induced long-period gratings in different silica fibers

    NASA Astrophysics Data System (ADS)

    Ranjan, Rajeev; Esposito, Flavio; Campopiano, Stefania; Iadicicco, Agostino

    2017-05-01

    In this work, we report on recent results about the fabrication of Long Period Gratings (LPGs) in different single mode optical fibers, by means of Electric Arc Discharge (EAD) technique. In particular, the results are related to three optical fibers with different doping elements, i.e.: standard telecommunication Ge-doped SMF28, highly photosensitive B/Gecodoped PS1250/1500, and P-doped P-SM-5 fibers. EAD leads to a point-by-point LPG inscription, due to localized tapering of the transversal size of the core and cladding regions along the fiber, and to changes of the silica refractive index due to the stress relaxation induced by local hot spots. Here, we take into consideration both standard and unconventional silica fibers and the aim of the work is to identify an appropriate "recipe" for each fiber, for manufacturing LPGs with strong and narrow attenuation bands (depth higher than 25 dB) and trivial power losses (<0.5 dB). Indeed, a proper combination of arc power and duration, as well as fiber tension, allows for the appropriate core and cladding modulation and thus for the desired LPGs spectral features. The sensitivity characteristics towards surrounding refractive index (SRI) and temperature changes of these LPGs are also investigated, highlighting the effects of different kind of doping.

  4. Persistent digital hyperthermia over a 48 h period does not induce laminitis in horses.

    PubMed

    de Laat, Melody A; Pollitt, Christopher C; Walsh, Donald M; McGowan, Catherine M; Sillence, Martin N

    2012-06-01

    Persistent digital hyperthermia, presumably due to vasodilation, occurs during the developmental and acute stages of insulin-induced laminitis. The objectives of this study were to determine if persistent digital hyperthermia is the principal pathogenic mechanism responsible for the development of laminitis. The potent vasodilator, ATP-MgCl(2) was infused continuously into the distal phalanx of the left forefoot of six Standardbred racehorses for 48 h via intra-osseous infusion to promote persistent digital hyperthermia. The right forefoot was infused with saline solution and acted as an internal control. Clinical signs of lameness at the walk were not detected at 0 h, 24h or 48 h post-infusion. Mean ± SE hoof wall temperatures of the left forefoot (29.4 ± 0.25°C) were higher (P<0.05) than those on the right (27.5 ± 0.38°C). Serum insulin (15.0 ± 2.89 μIU/mL) and blood glucose (5.4 ± 0.22 mM) concentrations remained unchanged during the experiment. Histopathological evidence of laminitis was not detected in any horse. The results demonstrated that digital vasodilation up to 30°C for a period of 48 h does not trigger laminitis in the absence of hyperinsulinaemia. Thus, although digital hyperthermia may play a role in the pathogenesis of laminitis, it is not the sole mechanism involved.

  5. Laser-induced periodic surface structures of thin, complex multi-component films

    NASA Astrophysics Data System (ADS)

    Reif, Juergen; Varlamova, Olga; Ratzke, Markus; Uhlig, Sebastian

    2016-04-01

    Femtosecond laser-induced regular nanostructures are generated on a complex multilayer target, namely a piece of a commercial, used hard disk memory. It is shown that after single-shot 800-nm irradiation at 0.26 J/cm2 only the polymer cover layer and—in the center—a portion of the magnetic multilayer are ablated. A regular array of linearly aligned spherical 450-nm features at the uncovered interface between cover and magnetic layers appears not to be produced by the irradiation. Only after about 10 pulses on one spot, classical ripples perpendicular to the laser polarization with a period of ≈700 nm are observed, with a modulation between 40 nm above and 40 nm below the pristine surface and an ablation depth only slightly larger than the thickness of the multilayer magnetic film. Further increase of the pulse number does not result in deeper ablation. However, 770-nm ripples become parallel to the polarization and are swelling to more than 120 nm above zero, much more than the full multilayer film thickness. In the spot periphery, much shallower 300-nm ripples are perpendicular to the strong modulation and the laser polarization. Irradiation with 0.49-J/cm2 pulses from an ultrafast white-light continuum results—in the spot periphery—in the formation of 200-nm ripples, only swelling above zero after removal of the polymer cover, without digging into the magnetic film.

  6. Periodic Lateralized Epileptiform Discharges can Survive Anesthesia and Result in Asymmetric Drug-induced Burst Suppression

    PubMed Central

    Mader, Edward C.; Cannizzaro, Louis A.; Williams, Frank J.; Lalan, Saurabh; Olejniczak, Piotr W.

    2017-01-01

    Drug-induced burst suppression (DIBS) is bihemispheric and bisymmetric in adults and older children. However, asymmetric DIBS may occur if a pathological process is affecting one hemisphere only or both hemispheres disproportionately. The usual suspect is a destructive lesion; an irritative or epileptogenic lesion is usually not invoked to explain DIBS asymmetry. We report the case of a 66-year-old woman with new-onset seizures who was found to have a hemorrhagic cavernoma and periodic lateralized epileptiform discharges (PLEDs) in the right temporal region. After levetiracetam and before anesthetic antiepileptic drugs (AEDs) were administered, the electroencephalogram (EEG) showed continuous PLEDs over the right hemisphere with maximum voltage in the posterior temporal region. Focal electrographic seizures also occurred occasionally in the same location. Propofol resulted in bihemispheric, but not in bisymmetric, DIBS. Remnants or fragments of PLEDs that survived anesthesia increased the amplitude and complexity of the bursts in the right hemisphere leading to asymmetric DIBS. Phenytoin, lacosamide, ketamine, midazolam, and topiramate were administered at various times in the course of EEG monitoring, resulting in suppression of seizures but not of PLEDs. Ketamine and midazolam reduced the rate, amplitude, and complexity of PLEDs but only after producing substantial attenuation of all burst components. When all anesthetics were discontinued, the EEG reverted to the original preanesthesia pattern with continuous non-fragmented PLEDs. The fact that PLEDs can survive anesthesia and affect DIBS symmetry is a testament to the robustness of the neurodynamic processes underlying PLEDs. PMID:28286626

  7. Formation of organic layer on femtosecond laser-induced periodic surface structures

    NASA Astrophysics Data System (ADS)

    Yasumaru, Naoki; Sentoku, Eisuke; Kiuchi, Junsuke

    2017-05-01

    Two types of laser-induced periodic surface structures (LIPSS) formed on titanium by femtosecond (fs) laser pulses (λ = 800 nm, τ = 180 fs, ν = 1 kHz) in air were investigated experimentally. At a laser fluence F above the ablation threshold, LIPSS with a minimum mean spacing of D < λ⁄2 were observed perpendicular to the laser polarization direction. In contrast, for F slightly below than the ablation threshold, ultrafine LIPSS with a minimum value of D < λ/10 were formed parallel to the polarization direction. The surface roughness of the parallel-oriented LIPSS was almost the same as that of the non-irradiated surface, unlike the high roughness of the perpendicular-oriented LIPSS. In addition, although the surface state of the parallel-oriented LIPSS was the same as that of the non-irradiated surface, the perpendicular-oriented LIPSS were covered with an organic thin film similar to a cellulose derivative that cannot be easily formed by conventional chemical synthesis. The results of these surface analyses indicate that these two types of LIPSS are formed through different mechanisms. This fs-laser processing technique may become a new technology for the artificial synthesis of cellulose derivatives.

  8. 100 nm period gratings produced by lithographically induced self-construction

    NASA Astrophysics Data System (ADS)

    Lei, Xinya; Wu, Lin; Deshpande, Paru; Yu, Zhaoning; Wu, Wei; Ge, Haixiong; Chou, Stephen Y.

    2003-07-01

    In this paper we report a technique that allows a fast replication of sub-100 nm scale patterns in a thin polymer film on a substrate from a patterned mask. Using the new pattern transfer technique, we fabricated 100 nm period polymer gratings with a 50 nm linewidth above a Si substrate as an example to demonstrate its capability of producing sub-100 nm nanostructures with direct industrial applications. In our technique, a mask with protruding patterns is used to induce similar pattern formation in the molten polymer film through an electrohydrodynamic instability process. A solid positive replica of the mask is obtained by cooling the polymer below its glass transition temperature. The mask is removed afterwards for the next fabrication procedure. The polymer structures formed can be used either directly as functional devices or as etching masks for further lithography processes. The mechanism that leads to the instability and subsequent pattern formation in the polymer layer is explained. Several important physical parameters that control the whole instability process are also identified. Our theory and experiments show that the pattern transfer technique developed here is well suited for the fabrication of sub-100 nm surface patterns in thin polymer films.

  9. Inducing subwavelength periodic nanostructures on multilayer NiPd thin film by low-fluence femtosecond laser beam

    NASA Astrophysics Data System (ADS)

    Kovačević, Aleksander G.; Petrović, Suzana; Lazović, Vladimir; Peruško, Davor; Pantelić, Dejan; Jelenković, Branislav M.

    2017-09-01

    During femtosecond interaction with surfaces, the processes of liquid and solid-state dewetting could be responsible for the generation and regrouping of nanoparticles and nanoparticle clusters. The occurrence of surface plasmon polariton most probably induces the LIPSS arrangement. We have used low-fluence scanning femtosecond beam to generate sub-wavelength periodic structures on multilayer Ni/Pd thin films on Si. The spatial period of LIPSS increases with the change of scanning directions in respect to the polarization direction due to the phase difference increase between the incoming and induced oscillations.

  10. Post-treatment techniques for enhancing mode-coupling in long period fiber gratings induced by CO2 laser

    NASA Astrophysics Data System (ADS)

    Xu, Xizhen; Tang, Jian; Zhao, Jing; Yang, Kaiming; Fu, Cailing; Wang, Qiao; Liu, Shen; Liao, Changrui; Lian, Jiarong; Wang, Yiping

    2015-12-01

    Two promising post-treatment techniques, i.e. applying tensile strain and rising temperature, are demonstrated to enhance the mode-coupling efficiency of the CO2-laser-induced long period fiber gratings (LPFGs) with periodic grooves. Such two post-treatment techniques can be used to enhance the resonant attenuation of the grating to achieve a LPFG-based filter with an extremely large attenuation and to tailor the transmission spectrum of the CO2-laser-induced LPFG after grating fabrication.

  11. Temperament moderates the influence of periadolescent social experience on behavior and adrenocortical activity in adult male rats.

    PubMed

    Caruso, M J; McClintock, M K; Cavigelli, S A

    2014-08-01

    Adolescence is a period of significant behavioral and physiological maturation, particularly related to stress responses. Animal studies that have tested the influence of adolescent social experiences on stress-related behavioral and physiological development have led to complex results. We used a rodent model of neophobia to test the hypothesis that the influence of adolescent social experience on adult behavior and adrenocortical function is modulated by pre-adolescent temperament. Exploratory activity was assessed in 53 male Sprague-Dawley rats to classify temperament and then they were housed in one of the three conditions during postnatal days (PND) 28-46: (1) with familiar kin, (2) with novel social partners, or (3) individually with no social partners. Effects on adult adrenocortical function were evaluated from fecal samples collected while rats were individually-housed and exposed to a 1-hour novel social challenge during PND 110-114. Adolescent-housing with novel or no social partners led to reduced adult glucocorticoid production compared to adolescent-housing with familiar littermates. Additionally, highly-exploratory pre-weanling rats that were housed with novel social partners during adolescence exhibited increased exploratory behavior and a more rapid return to basal glucocorticoid production in adulthood compared to those housed with familiar or no social partners during adolescence and compared to low-exploratory rats exposed to novel social partners. In sum, relatively short-term adolescent social experiences can cause transient changes in temperament and potentially longer-term changes in recovery of glucocorticoid production in response to adult social challenges. Furthermore, early temperament may modulate the influence of adolescent experiences on adult behavioral and adrenocortical function. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Definition of critical periods for Hedgehog pathway antagonist-induced holoprosencephaly, cleft lip, and cleft palate.

    PubMed

    Heyne, Galen W; Melberg, Cal G; Doroodchi, Padydeh; Parins, Kia F; Kietzman, Henry W; Everson, Joshua L; Ansen-Wilson, Lydia J; Lipinski, Robert J

    2015-01-01

    The Hedgehog (Hh) signaling pathway mediates multiple spatiotemporally-specific aspects of brain and face development. Genetic and chemical disruptions of the pathway are known to result in an array of structural malformations, including holoprosencephaly (HPE), clefts of the lip with or without cleft palate (CL/P), and clefts of the secondary palate only (CPO). Here, we examined patterns of dysmorphology caused by acute, stage-specific Hh signaling inhibition. Timed-pregnant wildtype C57BL/6J mice were administered a single dose of the potent pathway antagonist vismodegib at discrete time points between gestational day (GD) 7.0 and 10.0, an interval approximately corresponding to the 15th to 24th days of human gestation. The resultant pattern of facial and brain dysmorphology was dependent upon stage of exposure. Insult between GD7.0 and GD8.25 resulted in HPE, with peak incidence following exposure at GD7.5. Unilateral clefts of the lip extending into the primary palate were also observed, with peak incidence following exposure at GD8.875. Insult between GD9.0 and GD10.0 resulted in CPO and forelimb abnormalities. We have previously demonstrated that Hh antagonist-induced cleft lip results from deficiency of the medial nasal process and show here that CPO is associated with reduced growth of the maxillary-derived palatal shelves. By defining the critical periods for the induction of HPE, CL/P, and CPO with fine temporal resolution, these results provide a mechanism by which Hh pathway disruption can result in "non-syndromic" orofacial clefting, or HPE with or without co-occurring clefts. This study also establishes a novel and tractable mouse model of human craniofacial malformations using a single dose of a commercially available and pathway-specific drug.

  13. Refractory period after exercise-induced asthma unexplained by respiratory heat loss.

    PubMed

    Ben-Dov, I; Bar-Yishay, E; Godfrey, S

    1982-05-01

    Fifteen asthmatic children and young adults each exercised for 6 min by cycling on a cycle ergometer while breathing either cold (4.1 degrees C +/- 0.5 SEM) and dry (2.05 mg/L +/- 0.05) air or warm (37.2 degrees C +/- 0.3) fully saturated air. Each subject performed 4 tests arranged in pairs. Test pair A consisted of cold dry exercise followed by another cold dry exercise and test pair B consisted of a warm humid exercise followed by a cold dry exercise. Ventilation, heart rate, and gas exchange were closely matched in all 4 tests in each subject with a mean oxygen consumption of 34.8 +/- 0.8 ml/min/kg. In test pair A, all subjects were rendered refractory by the first cold dry exercise as manifested by a significant attenuation of their exercise-induced asthma (EIA) after the second cold dry test (per cent decrease in FEV1, delta FEV1 = 16 +/- 4 compared with 38 +/- 4). In 3 subjects, the warm humid exercise did not cause EIA and did not render them refractory to the second cold dry exercise. The 12 remaining subjects exhibited a refractory period similar to that shown in test pair A. They did not develop EIA after the warm humid test (delta FEV1 = 1 +/- 2), but after the subsequent cold dry exercise the per cent decrease in FEV1 was 19 +/- 3, similar to that in the second of the 2 cold dry exercise tests. These experiments suggest that in the majority of subjects exercise per se appears to be the cause for refractoriness and not airway cooling or bronchoconstriction.

  14. Dynamics of femtosecond laser-induced periodic surface structures on silicon by high spatial and temporal resolution imaging

    SciTech Connect

    Jia, X.; Jia, T. Q. Peng, N. N.; Feng, D. H.; Zhang, S. A.; Sun, Z. R.

    2014-04-14

    The formation dynamics of periodic ripples induced by femtosecond laser pulses (pulse duration τ = 50 fs and central wavelength λ = 800 nm) are studied by a collinear pump-probe imaging technique with a temporal resolution of 1 ps and a spatial resolution of 440 nm. The ripples with periods close to the laser wavelength begin to appear upon irradiation of two pump pulses at surface defects produced by the prior one. The rudiments of periodic ripples emerge in the initial tens of picoseconds after fs laser irradiation, and the ripple positions keep unmoved until the formation processes complete mainly in a temporal span of 1500 ps. The results suggest that the periodic deposition of laser energy during the interaction between femtosecond laser pulses and sample surface plays a dominant role in the formation of periodic ripples.

  15. Evolution of residual-strain distribution through an overload-induced retardation period during fatigue-crack growth

    NASA Astrophysics Data System (ADS)

    Lee, S. Y.; Sun, Y.; An, K.; Choo, H.; Hubbard, C. R.; Liaw, P. K.

    2010-01-01

    Neutron diffraction was employed to investigate the crack-growth retardation phenomenon after a single tensile overload by mapping both one-dimensional and two-dimensional residual-strain distributions around the crack tip in a series of compact-tension specimens representing various crack-growth stages through an overload-induced retardation period. The results clearly show a large compressive residual-strain field near the crack tip immediately after the overload. As the fatigue crack propagates through the overload-induced plastic zone, the compressive residual strains are gradually relaxed, and a new compressive residual-strain field is developed around the propagating crack tip, illustrating that the subsequent fatigue-induced plastic zone grows out of the large plastic zone caused by the overloading. The relationship between the overload-induced plastic zone and subsequent fatigue-induced plastic zone, and its influence on the residual-strain distributions in the perturbed plastic zone are discussed.

  16. High spatial frequency laser induced periodic surface structure formation in germanium by mid-IR femtosecond pulses

    NASA Astrophysics Data System (ADS)

    Austin, Drake. R.; Kafka, Kyle R. P.; Lai, Yu Hang; Wang, Zhou; Zhang, Kaikai; Li, Hui; Blaga, Cosmin I.; Yi, Allen Y.; DiMauro, Louis F.; Chowdhury, Enam A.

    2016-10-01

    Formation of high spatial frequency laser induced periodic surface structures (HSFL) in germanium by 90 fs mid-IR pulses at a 1 kHz repetition rate with wavelengths between λ = 2 and 3.6 μm was studied with varying angle of incidence and polarization. The period of these structures varied from λ/3 to λ/8. A modified surface-scattering model including Drude excitation and the optical Kerr effect explains the spatial period scaling of HSFL across the mid-IR wavelengths. Transmission electron microscopy shows the presence of a 30 nm amorphous layer above the structure of crystalline germanium. Various mechanisms including two photon absorption and defect-induced amorphization are discussed as probable causes for the formation of this layer.

  17. Bandpass filter with adjustable bandwidth based on a press-induced long-period twisted holey-fiber grating.

    PubMed

    Torres-Gómez, I; Martínez-Ríos, A; Ceballos-Herrera, D E; Mejía-Beltrán, E; Selvas-Aguilar, R

    2007-12-01

    A bandpass filter with adjustable bandwidth based on a press-induced long-period grating in a twisted holey fiber is presented. By twisting the holey fiber prior to the application of periodic pressure, each rejection band of the nontwisted induced long-period grating is split into two shifted rejection bands that move further apart as the twist ratio increases. This feature results in a wide bandpass filter with controllable bandwidth. A bandpass filter at 1523 nm with adjustable bandwidth from 15 to 65 nm with near-linear response and insertion loss lower than 0.7 dB is demonstrated. Additionally, the bandpass filter can be tuned over 100 nm.

  18. Periodic Mechanical Stress INDUCES Chondrocyte Proliferation and Matrix Synthesis via CaMKII-Mediated Pyk2 Signaling.

    PubMed

    Liang, Wenwei; Li, Zeng; Wang, Zhen; Zhou, Jinchun; Song, Huanghe; Xu, Shun; Cui, Weiding; Wang, Qing; Chen, Zhefeng; Liu, Feng; Fan, Weimin

    2017-01-01

    Periodic mechanical stress can promote chondrocyte proliferation and matrix synthesis to improve the quality of tissue-engineered cartilage. Although the integrin β1-ERK1/2 signal cascade has been implicated in periodic mechanical stress-induced mitogenic effects in chondrocytes, the precise mechanisms have not been fully established. The current study was designed to probe the roles of CaMKII and Pyk2 signaling in periodic mechanical stress-mediated chondrocyte proliferation and matrix synthesis. Chondrocytes were subjected to periodic mechanical stress, proliferation was assessed by direct cell counting and CCK-8 assay; gene expressions were analyzed using quantitative real-time PCR, protein abundance by Western blotting. Mechanical stress, markedly enhanced the phosphorylation levels of Pyk2 at Tyr402 and CaMKII at Thr286. Both suppression of Pyk2 with Pyk2 inhibitor PF431396 or Pyk2 shRNA and suppression of CaMKII with CaMKII inhibitor KN-93 or CaMKII shRNA blocked periodic mechanical stress-induced chondrocyte proliferation and matrix synthesis. Additionally, either pretreatment with KN-93 or shRNA targeted to CaMKII prevented the activation of ERK1/2 and Pyk2 under conditions of periodic mechanical stress. Interestingly, in relation to periodic mechanical stress, in the context of Pyk2 inhibition with PF431396 or its targeted shRNA, only the phosphorylation levels of ERK1/2 were abrogated, while CaMKII signal activation was not affected. Moreover, the phosphorylation levels of CaMKII- Thr286 and Pyk2- Tyr402 were abolished after pretreatment with blocking antibody against integrinβ1 exposed to periodic mechanical stress. Our results collectively indicate that periodic mechanical stress promotes chondrocyte proliferation and matrix synthesis through the integrinβ1-CaMKII-Pyk2-ERK1/2 signaling cascade. © 2017 The Author(s). Published by S. Karger AG, Basel.

  19. A search for five month solar induced periodicity in the stratosphere

    SciTech Connect

    Chandra, S. )

    1989-07-01

    Recent studies of solar UV spectra and various indices of solar activity indicate a strong period at about 5 months. In the 10.7 cm solar radio flux (F10.7), a conventional index for the solar EUV and UV variabilities, the spectral power of the 5 month period is comparable to the well known 27 day solar period. However, in the solar UV flux at 205 nm, directly measured from the Nimbus-7 SBUV spectrometer, the (spectral) power of the 5 month period is about half that of the 27 day period. This paper examines the possible impact of the 5 month solar period on ozone and temperature at various pressure levels in the stratosphere and discusses the implications of differences in solar forcing at the 27 day and 5 month periods. It is shown that ozone, both in the lower and upper stratosphere, has a measurable response to solar UV forcing 27 days. Such a solar response is not observed at 5 month period because of a relatively weaker 5 month solar UV component in the solar signal and a strong interference from dynamical signals associated with planetary wave activity.

  20. Controlled growth of periodically aligned copper-silicide nanocrystal arrays on silicon directed by laser-induced periodic surface structures (LIPSS)

    NASA Astrophysics Data System (ADS)

    Nürnberger, Philipp; Reinhardt, Hendrik M.; Rhinow, Daniel; Riedel, René; Werner, Simon; Hampp, Norbert A.

    2017-10-01

    In this paper we introduce a versatile tool for the controlled growth and alignment of copper-silicide nanocrystals. The method takes advantage of a unique self-organization phenomenon denoted as laser-induced periodic surface structures (LIPSS). Copper films (3 ± 0.2 nm) are sputter-deposited onto single crystal silicon (100) substrates with a thin oxide layer (4 ± 0.2 nm), and subsequently exposed to linearly polarized nanosecond laser pulses (τ ≈ 6 ns) at a central wavelength of 532 nm. The irradiation triggers dewetting of the Cu film and simultaneous formation of periodic Cu nanowires (LIPSS), which partially penetrate the oxide layer to the Si substrate. These LIPSS act as nucleation centers for the growth of Cu-Si crystals during thermal processing at 500 °C under forming gas 95/5 atmosphere. Exemplified by our model system Cu/SiO2/Si, LIPSS are demonstrated to facilitate the diffusion reaction between Cu and underlying Si. Moreover, adjustment of the laser polarization allows us to precisely control the nanocrystal alignment with respect to the LIPSS orientation. Potential applications and conceivable alternatives of this process are discussed.

  1. Periodic structure with a periodicity of 2-3.5 μm on crystalline TiO2 induced by unpolarized KrF excimer lasers

    NASA Astrophysics Data System (ADS)

    He, Rong; Ma, Hongliang; Zheng, Jiahui; Han, Yongmei; Lu, Yuming; Cai, Chuanbing

    2016-08-01

    Laser-induced periodic surface structures (LIPSS) were processed on the TiO2 bulk surface under the irradiation of 248 nm unpolarized KrF excimer laser pulses in air. Spatial LIPSS periods ranging from 2 to 3.5 μm are ascribed to the capillary wave. These microstructures were analyzed at different laser pulse numbers with the laser energy from 192 to 164 mJ. The scanning electron microscopy results indicated eventually stripes that have been disrupted as the increase in the laser pulse numbers, which is reasonably explained by the energy accumulating effect. In addition, investigations were concentrated on the surface modifications at pre-focal plane, focal plane and post-focal plane in the same defocusing amount. Compared with condition at pre-focal plane, in addition to the plasma produced at target, the air was also breakdown for the situation of post-focal plane. So it was reasonable that stripes appeared at pre-focal plane but not at post-focal plane.

  2. Femtosecond laser induced periodic nanostructures on titanium dioxide film for improving biocompatibility

    NASA Astrophysics Data System (ADS)

    Shinonaga, T.; Horiguchi, N.; Tsukamoto, M.; Nagai, A.; Yamashita, K.; Hanawa, T.; Matsushita, N.; Guoqiang, X.; Abe, N.

    2013-03-01

    Periodic nanostructures formation on Titanium dioxide (TiO2) film by scanning of femtosecond laser beam spot at fundamental and second harmonic wave is reported. Titanium (Ti) is one of the most widely used for biomaterials, because of its excellent anti-corrosion and high mechanical properties. However, Ti implant is typically artificial materials and has no biofunction. Hence, it is necessary for improving the bioactivity of Ti. Recently, coating of TiO2 film on Ti plate surface is useful methods to improve biocompatibility of Ti plate. Then, if periodic nanostructures were formed on the film surface, cell spreading might be controlled at one direction. We propose periodic nanostructures formation on TiO2 film by femtosecond laser irradiation. Cell spread could be controlled along the grooves of periodic nanostructures. In the experiments, the film was formed on Ti plate with an aerosol beam. A commercial femtosecond Ti : sapphire laser system was employed in our experiments. Periodic nanostructures, lying perpendicular to the laser electric field polarization vector, were formed on the film at fundamental and second harmonic wave. Periodic nanostructures were also produced on Ti plate with femtosecond laser. The period of periodic nanostructures on the film was much shorter than that on Ti plate. By cell test, there was a region of cell spreading along the grooves of periodic nanostructures on the film formed with femtosecond laser at fundamental wave. On bare film surface, cell spreading was observed at all direction. These results suggest that direction of cell spread could be controlled by periodic nanostructures formation on the film.

  3. Wavelength tunability of L-band fiber ring lasers using mechanically induced long-period fiber gratings

    NASA Astrophysics Data System (ADS)

    Sakata, Hajime; Yoshimi, Hitoshi; Otake, Yuki

    2009-03-01

    We report on oscillation wavelength control in erbium-doped fiber ring lasers by adjusting the period of a mechanically induced long-period fiber grating (LPFG) inserted into the fiber ring resonator. Pump light is provided by a 974 nm laser diode (LD), the emission of which is coupled into the fiber ring resonator through a wavelength-division multiplexing coupler. Laser oscillation occurs with a threshold pump LD current of 40 mA, corresponding to a threshold pump power of 5 mW. When a periodic pressure of 0.81 N/mm is applied to form the LPFG, the fiber ring laser exhibits the tunable range of 40.9 nm, i.e., from 1563.1 to 1604 nm, by changing the grating period.

  4. Femtosecond laser-induced periodic nanostructure creation on PET surface for controlling of cell spreading

    NASA Astrophysics Data System (ADS)

    Sato, Yuji; Tsukamoto, Masahiro; Shinonaga, Togo; Kawa, Takuya

    2016-03-01

    A new method of periodic nanostructure formation on a polyethylene terephthalate (PET) surface has been developed, employing a femtosecond laser with a wavelength of 1045 nm. To generate structured films, the PET was placed in contact with a silicon (Si) wafer, followed by irradiation with the laser focused on the Si wafer, passing through the PET film. In order to evaluate the surface morphology, atomic force microscopy analysis was conducted on both treated and untreated PET surfaces. From the results, nanostructures with a period of 600 nm and height of 100 nm were formed on the PET film surface by laser treatment. A cell cultivation test was carried out on PET films with and without periodic nanostructures, showing that for nanostructured films, the cells (MG-63) were spread along the periodic grooves; in contrast, random cell spreading was observed for cultures grown on the untreated PET film.

  5. Observation of self-assembled periodic nano-structures induced by femtosecond laser in both ablation and deposition regimes

    NASA Astrophysics Data System (ADS)

    Tang, Mingzhen; Zhang, Haitao; Her, Tsing-Hua

    2008-02-01

    We observed the spontaneous formation of periodic nano-structures in both femtosecond laser ablation and deposition. The former involved 400-nm femtosecond pulses from a 250-KHz regenerated amplified mode-locked Ti:sapphire laser and periodic nanocracks and the nano-structure are in the form of periodic nanocracks in the substrate, the latter applied an 80-MHz mode-locked Ti:sapphire oscillator with pulse energy less than half nanojoule in a laser-induced chemical vapor deposition configuration and tungsten nanogratings grow heterogeneously on top of the substrates. These two observed periodic nanostructures have opposite orientations respecting to laser polarization: the periodic nanocracks are perpendicular to, whereas the deposited tungsten nanogratings are parallel to laser polarization direction. By translating the substrate respecting to the laser focus, both the periodic nanocrack and tungsten nanograting extend to the whole scanning range. The deposited tungsten nanogratings possess excellent uniformity on both the grating period and tooth length. Both the attributes can be tuned precisely by controlling the laser power and scanning speed. Furthermore, we discovered that the teeth of transverse tungsten nanogratings are self aligned along their axial direction during multiple scanning with appropriate offset between scans. We demonstrate the feasibility of fabricating large-area one-dimensional grating by exploiting such unique property. These distinct phenomena of nanocracks and tungsten nanogratings indicate different responsible mechanisms.

  6. Midkine Is a Novel Regulator of Amphetamine-Induced Striatal Gliosis and Cognitive Impairment: Evidence for a Stimulus-Dependent Regulation of Neuroinflammation by Midkine

    PubMed Central

    Vicente-Rodríguez, Marta; Fernández-Calle, Rosalía; Gramage, Esther; Pérez-García, Carmen; Ramos, María P.

    2016-01-01

    Midkine (MK) is a cytokine that modulates amphetamine-induced striatal astrogliosis, suggesting a possible role of MK in neuroinflammation induced by amphetamine. To test this hypothesis, we studied astrogliosis and microglial response induced by amphetamine (10 mg/kg i.p. four times, every 2 h) in different brain areas of MK−/− mice and wild type (WT) mice. We found that amphetamine-induced microgliosis and astrocytosis are enhanced in the striatum of MK−/− mice in a region-specific manner. Surprisingly, LPS-induced astrogliosis in the striatum was blocked in MK−/− mice. Since striatal neuroinflammation induced by amphetamine-type stimulants correlates with the cognitive deficits induced by these drugs, we also tested the long-term effects of periadolescent amphetamine treatment (3 mg/kg i.p. daily for 10 days) in a memory task in MK−/− and WT mice. Significant deficits in the Y-maze test were only observed in amphetamine-pretreated MK−/− mice. The data demonstrate for the first time that MK is a novel modulator of neuroinflammation depending on the inflammatory stimulus and the brain area considered. The data indicate that MK limits amphetamine-induced striatal neuroinflammation. In addition, our data demonstrate that periadolescent amphetamine treatment in mice results in transient disruption of learning and memory processes in absence of endogenous MK. PMID:28044069

  7. Midkine Is a Novel Regulator of Amphetamine-Induced Striatal Gliosis and Cognitive Impairment: Evidence for a Stimulus-Dependent Regulation of Neuroinflammation by Midkine.

    PubMed

    Vicente-Rodríguez, Marta; Fernández-Calle, Rosalía; Gramage, Esther; Pérez-García, Carmen; Ramos, María P; Herradón, Gonzalo

    2016-01-01

    Midkine (MK) is a cytokine that modulates amphetamine-induced striatal astrogliosis, suggesting a possible role of MK in neuroinflammation induced by amphetamine. To test this hypothesis, we studied astrogliosis and microglial response induced by amphetamine (10 mg/kg i.p. four times, every 2 h) in different brain areas of MK-/- mice and wild type (WT) mice. We found that amphetamine-induced microgliosis and astrocytosis are enhanced in the striatum of MK-/- mice in a region-specific manner. Surprisingly, LPS-induced astrogliosis in the striatum was blocked in MK-/- mice. Since striatal neuroinflammation induced by amphetamine-type stimulants correlates with the cognitive deficits induced by these drugs, we also tested the long-term effects of periadolescent amphetamine treatment (3 mg/kg i.p. daily for 10 days) in a memory task in MK-/- and WT mice. Significant deficits in the Y-maze test were only observed in amphetamine-pretreated MK-/- mice. The data demonstrate for the first time that MK is a novel modulator of neuroinflammation depending on the inflammatory stimulus and the brain area considered. The data indicate that MK limits amphetamine-induced striatal neuroinflammation. In addition, our data demonstrate that periadolescent amphetamine treatment in mice results in transient disruption of learning and memory processes in absence of endogenous MK.

  8. Highly periodic laser-induced nanostructures on thin Ti and Cu foils for potential application in laser ion acceleration

    SciTech Connect

    Das, Susanta Kumar; Andreev, Alexander; Braenzel, Julia; Schnuerer, Matthias; Grunwald, Ruediger; Messaoudi, Hamza

    2016-03-21

    The feasibility of femtosecond laser-induced periodic nanostructures on thin Ti and Cu foils (thickness down to 1 μm) is demonstrated. At pulse durations of 120 fs and a wavelength of 400 nm, periods of 61 nm to 320 nm were obtained. Particle-in-cell simulations of laser ion acceleration processes with such nanostructured targets indicate their potential for high energy particle physics applications. In particular, a measurable enhancement of the proton cut-off energy and a significant enhancement of the number of accelerated particles compared to non- or weakly structured targets of same thickness and material are expected.

  9. [Pulmonary metabolism of beta-endorphin in asthmatic patients in asymptomatic periods and after bronchospasm induced by methacholine].

    PubMed

    Bottino, G; Antognozzi, G; Degrandi, R; Augeri, C; Bogliolo, G; Zoccali, P

    1995-01-01

    Blood concentration of endogenous beta-endorphines can change during the clinical evolution of chronic bronchopneumopathies. The authors assessed the beta-endorphine concentrations in the pulmonary arterial and systemic arterial blood in 8 asthmatic patients during a symptom-free period and after methacholine-induced bronchospasm. The beta-endorphine analysis was performed in duplicate dor each sample, by means of a RIA assay. There is not difference in the systemic arterial blood concentration of beta-endorphines between asthmatic patients and normal subjects. Furthermore, there is no change in the beta-endorphine blood concentration during the passage through the pulmonary tissue after methacoline-induced bronchospasm.

  10. Earthquake Induced Damage Mechanism of Long Period Structures Using Energy Response

    SciTech Connect

    Du Yongfeng; Li Hui

    2008-07-08

    This paper presents a method of expounding the damage of RC long period frame structure using energy analysis method. Since the damage of structures usually occurs under major earthquakes, the structure is assumed to be in elasto-plastic state, and degraded Bouc-Wen model is used to describe the hysteretic component of the restoring force. A double index damage criterion defined by the maximum drift and energy absorption is used as the damage criterion. The energy transferring relation in a structure is derived, and both momentary and cumulative energy response is used to reflect the delay of the collapse of a long period structure. The mechanism of collapse delay of the long period structure is suggested through a numerical example combing the energy response and time history response.

  11. Diffusion-induced periodic transition between oscillatory modes in amplitude-modulated patterns

    SciTech Connect

    Tang, Xiaodong; He, Yuxiu; Wang, Shaorong; Gao, Qingyu; Epstein, Irving R.; Wang, Qun

    2014-06-15

    We study amplitude-modulated waves, e.g., wave packets in one dimension, overtarget spirals and superspirals in two dimensions, under mixed-mode oscillatory conditions in a three-variable reaction-diffusion model. New transition zones, not seen in the homogeneous system, are found, in which periodic transitions occur between local 1{sup N−1} and 1{sup N} oscillations. Amplitude-modulated complex patterns result from periodic transition between (N − 1)-armed and N-armed waves. Spatial recurrence rates provide a useful guide to the stability of these modulated patterns.

  12. On periodic solutions of Goodwin's business cycle model with only floor in induced investment

    NASA Astrophysics Data System (ADS)

    Antonova, A. O.; Reznik, S. N.; Todorov, M. D.

    2013-10-01

    We present here an analytical solution of Goodwin's business cycle model in the form of delay differential equation with fixed delay θ and piecewise linear accelerator with only the floor (or the ceiling). We conclude that in this model the time behavior of the solution similar to Goodwin's limit cycle is not possible. These solution looks similar to the oscillation with a period θ, the amplitude of the oscillation growing exponentially to infinity as t →∞. The conditions for existence of the periodic solution in Goodwin's model with fixed delay for the nonlinear accelerator are also discussed.

  13. Postnatal methylmercury exposure induces hyperlocomotor activity and cerebellar oxidative stress in mice: dependence on the neurodevelopmental period.

    PubMed

    Stringari, James; Meotti, Flávia C; Souza, Diogo O; Santos, Adair R S; Farina, Marcelo

    2006-04-01

    During the early postnatal period the central nervous system (CNS) is extremely sensitive to external agents. The present study aims at the investigation of critical phases where methylmercury (MeHg) induces cerebellar toxicity during the suckling period in mice. Animals were treated with daily subcutaneous injections of MeHg (7 mg/kg of body weight) during four different periods (5 days each) at the early postnatal period: postnatal day (PND) 1-5, PND 6-10, PND 11-15, or PND 16-20. A control group was treated with daily subcutaneous injections of a 150 mM NaCl solution (10 ml/kg of body weight). Subjects exposed to MeHg at different postnatal periods were littermate. At PND 35, behavioral tests were performed to evaluate spontaneous locomotor activity in the open field and motor performance in the rotarod task. Biochemical parameters related to oxidative stress (levels of glutathione and thiobarbituric acid reactive substances, as well as glutathione peroxidase and glutathione reductase activity) were evaluated in cerebellum. Hyperlocomotor activity and high levels of cerebellar thiobarbituric acid reactive substances were observed in animals exposed to MeHg during the PND 11-15 or PND 16-20 periods. Cerebellar glutathione reductase activity decreased in MeHg-exposed animals. Cerebellar glutathione peroxidase activity was also decreased after MeHg exposure and the lowest enzymatic activity was found in animals exposed to MeHg during the later days of the suckling period. In addition, low levels of cerebellar glutathione were found in animals exposed to MeHg during the PND 16-20 period. The present results show that the postnatal exposure to MeHg during the second half of the suckling period causes hyperlocomotor activity in mice and point to this phase as a critical developmental stage where mouse cerebellum is a vulnerable target for the neurotoxic and pro-oxidative effects of MeHg.

  14. Learning and Memory Deficits in Male Adult Mice Treated with a Benzodiazepine Sleep-Inducing Drug during the Juvenile Period

    PubMed Central

    Furukawa, Yusuke; Tanemura, Kentaro; Igarashi, Katsuhide; Ideta-Otsuka, Maky; Aisaki, Ken-Ichi; Kitajima, Satoshi; Kitagawa, Masanobu; Kanno, Jun

    2016-01-01

    Gamma-aminobutyric acid (GABA), the major inhibitory neurotransmitter in the mammalian central nervous system, is also known to be important for brain development. Therefore, disturbances of GABA receptor (GABA-R) mediated signaling (GABA-R signal) during brain development may influence normal brain maturation and cause late-onset brain malfunctions. In this study, we examined whether the stimulation of the GABA-R signal during brain development induces late-onset adverse effects on the brain in adult male mice. To stimulate the GABA-R signal, we used either the benzodiazepine sleep-inducing drug triazolam (TZ) or the non-benzodiazepine drug zolpidem (ZP). We detected learning and memory deficits in mice treated with TZ during the juvenile period, as seen in the fear conditioning test. On the other hand, ZP administration during the juvenile period had little effect. In addition, decreased protein expression of GluR1 and GluR4, which are excitatory neurotransmitter receptors, was detected in the hippocampi of mice treated with TZ during the juvenile period. We measured mRNA expression of the immediate early genes (IEGs), which are neuronal activity markers, in the hippocampus shortly after the administration of TZ or ZP to juvenile mice. Decreased IEG expression was detected in mice with juvenile TZ administration, but not in mice with juvenile ZP administration. Our findings demonstrate that TZ administration during the juvenile period can induce irreversible learning and memory deficits in adult mice. It may need to take an extra care for the prescription of benzodiazepine sleep-inducing drugs to juveniles because it might cause learning and memory deficits. PMID:27489535

  15. Deafferentation-induced plasticity of visual callosal connections: predicting critical periods and analyzing cortical abnormalities using diffusion tensor imaging.

    PubMed

    Olavarria, Jaime F; Bock, Andrew S; Leigland, Lindsey A; Kroenke, Christopher D

    2012-01-01

    Callosal connections form elaborate patterns that bear close association with striate and extrastriate visual areas. Although it is known that retinal input is required for normal callosal development, there is little information regarding the period during which the retina is critically needed and whether this period correlates with the same developmental stage across species. Here we review the timing of this critical period, identified in rodents and ferrets by the effects that timed enucleations have on mature callosal connections, and compare it to other developmental milestones in these species. Subsequently, we compare these events to diffusion tensor imaging (DTI) measurements of water diffusion anisotropy within developing cerebral cortex. We observed that the relationship between the timing of the critical period and the DTI-characterized developmental trajectory is strikingly similar in rodents and ferrets, which opens the possibility of using cortical DTI trajectories for predicting the critical period in species, such as humans, in which this period likely occurs prenatally. Last, we discuss the potential of utilizing DTI to distinguish normal from abnormal cerebral cortical development, both within the context of aberrant connectivity induced by early retinal deafferentation, and more generally as a potential tool for detecting abnormalities associated with neurodevelopmental disorders.

  16. An integration of statistic method to track droughts periods induced by global change.

    NASA Astrophysics Data System (ADS)

    Djamel, Mimoun; Didier, Graillot

    2013-04-01

    During the last decades, droughts are occurring frequently in France, most notably in 1976, 1988, 1997 and 2003. This culminated in the severe drought of 2003 which affected mainly the south-east of Europe. Global climate models predict a prominent change in rainfall with wetter winters and drier summers over the medium latitude in the Northern Hemisphere. In France, regional climate models (ARPEGE) shows an increasing seasonal climatic variability with (a) hotter, drier summer and (b) an increase in the duration and severity of low-flow periods. The paper focuses on the temperate zone of the south-east of France on the catchment of the Ain river where water resources, consisting mainly of karstic and alluvial groundwater, are already a major concern today. This contribution tried to identify whether any trend in the annual and monthly series of rainfall already appears at the scale of this region and to obtain realistic previsions at 60 years. Two data sources have been used : (a) spatially interpolated historical data for the period 1970-2006 from the French weather service model SAFRAN (NCEP re-analysis for the MSLP field and the Meteo-France SAFRAN mesoscale analysis for the precipitation observations); and (b) the four SRES B2 scenarios namely Arpege_2, Arpege_1, Arpege_A2 and Arpege_B1 have been widely adopted as standard scenarios for the use in climate change impact studies. Scenario runs were taken over two time periods: a) 2010-2040 and b) 2041-2070. Drought characteristics over the study area were revealed by employing the Standardized Precipitation Index (SPI) in different time scales. Negative trends of the SPI drought index were recognized by using the Mann-Kendall non parametric test, which suggested that drought conditions were intensified through time. The trends observed in the 13 sub catchments of interest are consistent with those observed at a larger scale. The results indicated that the drought severity and duration will increase in the future

  17. Complex-periodic spiral waves in confluent cardiac cell cultures induced by localized inhomogeneities

    NASA Astrophysics Data System (ADS)

    Hwang, Seong-min; Kim, Tae Yun; Lee, Kyoung J.

    2005-07-01

    Spatiotemporal wave activities in excitable heart tissues have long been the subject of numerous studies because they underlie different forms of cardiac arrhythmias. In particular, understanding the dynamics and the instabilities of spiral waves have become very important because they can cause reentrant tachycardia and their subsequent transitions to fibrillation. Although many aspects of cardiac spiral waves have been investigated through experiments and model simulations, their complex properties are far from well understood. Here, we show that intriguing complex-periodic (such as period-2, period-3, period-4, or aperiodic) spiral wave states can arise in monolayer tissues of cardiac cell culture in vitro, and demonstrate that these different dynamic states can coexist with abrupt and spontaneous transitions among them without any change in system parameters; in other words, the medium supports multistability. Based on extensive image data analysis, we have confirmed that these spiral waves are driven by their tips tracing complex orbits whose unusual, meandering shapes are formed by delicate interplay between localized conduction blocks and nonlinear properties of the culture medium. Author contributions: S.-m.H. and K.J.L. designed research; S.-m.H. and T.Y.K. performed research; S.-m.H. contributed new reagents/analytic tools; S.-m.H., T.Y.K., and K.J.L. analyzed data; and S.-m.H. and K.J.L. wrote the paper.This paper was submitted directly (Track II) to the PNAS office.Abbreviations: IBI, interbeat interval; P-n, period-n.

  18. Surface birefringence of self-assembly periodic nanostructures induced on 6H-SiC surface by femtosecond laser

    NASA Astrophysics Data System (ADS)

    Song, Juan; Dai, Ye; Tao, Wenjun; Gong, Min; Ma, Guohong; Zhao, Quanzhong; Qiu, Jianrong

    2016-02-01

    In this paper, we report the birefringence effect of surface self-assembly periodic nanostructures induced on 6H-SiC by femtosecond laser irradiation. Birefringence characteristic (e.g. cross-polarized image), measured by cross polarized microscopy, was found to be controlled by both single pulse energy and scanning velocity. Comparing birefringence measurement results of nanostructures and morphology characterization by Scanning electron microscopy, it is shown that ∼200 nm-period deep-subwavelength periodic ripples (DSWR) plays a dominating role in the birefringence effect. Raman spectra show that the change of retardance with pulse energy and scanning velocity is most possibly caused by the thickness variation of DSWR. Finally, a light attenuator based on a single layer of DSWR structure on 6H-SiC surface was constructed and tested by light source of 800 nm to have a tunable attenuating ratio of 69-100%.

  19. Treatment of drug-induced psychosis in Parkinson's disease with ziprasidone can induce severe dose-dependent off-periods and pathological laughing.

    PubMed

    Schindehütte, Jan; Trenkwalder, Claudia

    2007-02-01

    "Atypical anti-psychotics" are substances of choice in treating drug-induced psychosis (DP) in Parkinson's disease (PD). We report on four patients with DP who received treatment with ziprasidone after previously applied clozapine and quetiapine had failed. Three patients showed a significant improvement of DP, without deterioration of motor function. In one case, ziprasidone considerably increased decline in off-periods. Two patients developed pathological laughing as a possible side-effect of ziprasidone. Ziprasidone may serve as an additional "atypical anti-psychotic" for the treatment of DP in PD but can also induce deterioration of motor function.

  20. Optical nanofiber-based cavity induced by periodic air-nanohole arrays

    NASA Astrophysics Data System (ADS)

    Li, Wenfang; Du, Jinjin; Truong, Viet Giang; Nic Chormaic, Síle

    2017-06-01

    We experimentally realized an optical nanofiber-based cavity by combining a 1-D photonic crystal and Bragg grating structures. The cavity morphology comprises a periodic, triplex air-cube introduced at the waist of the nanofiber. The cavity has been theoretically characterized using finite-difference time-domain simulations to obtain the reflection and transmission spectra. We have also experimentally measured the transmission spectra, and a Q-factor of ˜784 ± 87 for a very short periodic structure has been observed. The structure provides strong confinement of the cavity field, and its potential for optical network integration makes it an ideal candidate for use in nanophotonic and quantum information systems.

  1. Temperature variation induced by the pulsed-periodic laser pumping under terahertz wave generation

    NASA Astrophysics Data System (ADS)

    Kitaeva, G. Kh; Moiseenko, E. V.; Shepelev, A. V.

    2017-09-01

    During nonlinear-optical parametric frequency conversion the heat-related effects occur, considerably influencing the conversion process. We develop versatile methods for analytic and numerical calculations of thermo-optical parameters and the temperature distribution inside a non-linear crystal pumped by periodic laser pulses. As an example, numerical results are presented for a number of laser-based schemes actual for the non-linear optical terahertz wave generation and parametric frequency conversion processes.

  2. The efficacy of periodic +Gz exposure in the prevention of bedrest induced orthostatic intolerance

    NASA Technical Reports Server (NTRS)

    Ludwig, D. A.; Vernikos, J.; Duvoisin, M. R; Stinn, J. L.

    1992-01-01

    What is the most efficient dosage of periodic exposure to positive 1G(z) during microgravity to maintain a functional upright position after returning to a positive 1G(z) environment? The answer has implications for the type of countermeasures astronauts will be required to perform during long term space flight. Methods: Nine males were subjected to four different positive 1G exposure protocols plus a control protocol ('zero G(z)') during four days of continuous bedrest. The four positive 1G(z) exposures consisted of periodic standing or walking, each for a total period of two or four hours. Each subject was returned for bedrest on five different occasions over a period of approximately one year to obtain data on each of the nine subjects across all four positive 1G(z) treatments and the control. A 30 min tilt test was used to measure orthostatic response during pre and post bedrest. Results: In terms of survival rate (percentage of subjects who did not faint after 30 sec of tilt), four hours of intermittent standing was the only protocol that maintained a rate comparable to pre bedrest levels (87.5 percent). Although the other three positive 1G(z) protocols performed better than the 'zero G(z) control (22.2 percent), only the four hour standing returned post bedrest survival rates to pre bedrest levels. Conclusions: The results will need to be evaluated with regards to a variety of other physiological systems which are known to decondition during microgravitry.

  3. Plasmonic effects for light concentration in organic photovoltaic thin films induced by hexagonal periodic metallic nanospheres

    NASA Astrophysics Data System (ADS)

    Zhu, Jinfeng; Xue, Mei; Shen, Huajun; Wu, Zhe; Kim, Seongku; Ho, Jyh-Jier; Hassani-Afshar, Aram; Zeng, Baoqing; Wang, Kang L.

    2011-04-01

    We present a plasmonic nanostructure design by embedding a layer of hexagonal periodic metallic nanospheres between the active layer and transparent anode for bulk heterojunction organic solar cells. The hybrid structure shows broadband optical absorption enhancement from localized surface plasmon resonance with a weak dependence on polarization of incident light. We also theoretically study the optimization of the design to enhance the absorption up to 1.90 times for a typical hybrid active layer based on a low band gap material.

  4. Hyperpolarization-Activated Current Induces Period-Doubling Cascades and Chaos in a Cold Thermoreceptor Model.

    PubMed

    Xu, Kesheng; Maidana, Jean P; Caviedes, Mauricio; Quero, Daniel; Aguirre, Pablo; Orio, Patricio

    2017-01-01

    In this article, we describe and analyze the chaotic behavior of a conductance-based neuronal bursting model. This is a model with a reduced number of variables, yet it retains biophysical plausibility. Inspired by the activity of cold thermoreceptors, the model contains a persistent Sodium current, a Calcium-activated Potassium current and a hyperpolarization-activated current (Ih) that drive a slow subthreshold oscillation. Driven by this oscillation, a fast subsystem (fast Sodium and Potassium currents) fires action potentials in a periodic fashion. Depending on the parameters, this model can generate a variety of firing patterns that includes bursting, regular tonic and polymodal firing. Here we show that the transitions between different firing patterns are often accompanied by a range of chaotic firing, as suggested by an irregular, non-periodic firing pattern. To confirm this, we measure the maximum Lyapunov exponent of the voltage trajectories, and the Lyapunov exponent and Lempel-Ziv's complexity of the ISI time series. The four-variable slow system (without spiking) also generates chaotic behavior, and bifurcation analysis shows that this is often originated by period doubling cascades. Either with or without spikes, chaos is no longer generated when the Ih is removed from the system. As the model is biologically plausible with biophysically meaningful parameters, we propose it as a useful tool to understand chaotic dynamics in neurons.

  5. The EEG correlates of the TMS-induced EMG silent period in humans.

    PubMed

    Farzan, Faranak; Barr, Mera S; Hoppenbrouwers, Sylco S; Fitzgerald, Paul B; Chen, Robert; Pascual-Leone, Alvaro; Daskalakis, Zafiris J

    2013-12-01

    Application of magnetic or electrical stimulation to the motor cortex can result in a period of electromyography (EMG) silence in a tonically active peripheral muscle. This period of EMG silence is referred to as the silent period (SP). The duration of SP shows intersubject variability and reflects the integrity of cortical and corticospinal pathways. A non-invasive technique for assessing the duration of SP is the combination of Transcranial Magnetic Stimulation (TMS) with EMG. Utilizing TMS-EMG, several studies have reported on the shortening or lengthening of SP in neuropsychiatric disorders such as schizophrenia, bipolar disorder, depression, obsessive compulsive disorder, epilepsy, Parkinson's disease, and stroke. However, cortical, corticospinal and peripheral components are difficult to disentangle from EMG alone. Here, we use the multimodal neuroimaging technique of TMS-EMG combined with concurrent electroencephalography (EEG) recording to further examine the cortical origin of SP and the cortical oscillatory activity that underlies SP genesis. We demonstrate that the duration of SP is related to the temporal characteristics of the cortical reactivity and the power of delta to alpha oscillations in both local and remote areas ipsilateral and contralateral to the stimulation site, and beta oscillations locally. We illustrate that, compared to EMG, the EEG indices of the SP provide additional information about the brain dynamics and propose that the EEG measures of SP may be used in future clinical and research investigations to more precisely delineate the mechanisms underlying inhibitory impairments.

  6. The EEG Correlates of the TMS Induced EMG Silent Period in Humans

    PubMed Central

    Farzan, Faranak; Barr, Mera S.; Hoppenbrouwers, Sylco S.; Fitzgerald, Paul B.; Chen, Robert; Pascual-Leone, Alvaro; Daskalakis, Zafiris J.

    2014-01-01

    Application of magnetic or electrical stimulation to the motor cortex can result in a period of electromyography (EMG) silence in a tonically active peripheral muscle. This period of EMG silence is referred to as the silent period (SP). The duration of SP shows intersubject variability and reflects the integrity of cortical and corticospinal pathways. A non-invasive technique for assessing the duration of SP is the combination of Transcranial Magnetic Stimulation (TMS) with EMG. Utilizing TMS-EMG, several studies have reported on the shortening or lengthening of SP in neuropsychiatric disorders such as schizophrenia, bipolar disorder, depression, obsessive compulsive disorder, epilepsy, Parkinson’s disease, and stroke. However, cortical, corticospinal and peripheral components are difficult to disentangle from EMG alone. Here, we use the multimodal neuroimaging technique of TMS-EMG combined with concurrent electroencephalography (EEG) recording to further examine the cortical origin of SP and the cortical oscillatory activity that underlies SP genesis. We demonstrate that the duration of SP is related to the temporal characteristics of the cortical reactivity and the power of delta to alpha oscillations in both local and remote areas ipsilateral and contralateral to the stimulation site, and beta oscillations locally. We illustrate that, compared to EMG, the EEG indices of the SP provide additional information about the brain dynamics and propose that the EEG measures of SP may be used in future clinical and research investigations to more precisely delineate the mechanisms underlying inhibitory impairments. PMID:23800790

  7. Hyperpolarization-Activated Current Induces Period-Doubling Cascades and Chaos in a Cold Thermoreceptor Model

    PubMed Central

    Xu, Kesheng; Maidana, Jean P.; Caviedes, Mauricio; Quero, Daniel; Aguirre, Pablo; Orio, Patricio

    2017-01-01

    In this article, we describe and analyze the chaotic behavior of a conductance-based neuronal bursting model. This is a model with a reduced number of variables, yet it retains biophysical plausibility. Inspired by the activity of cold thermoreceptors, the model contains a persistent Sodium current, a Calcium-activated Potassium current and a hyperpolarization-activated current (Ih) that drive a slow subthreshold oscillation. Driven by this oscillation, a fast subsystem (fast Sodium and Potassium currents) fires action potentials in a periodic fashion. Depending on the parameters, this model can generate a variety of firing patterns that includes bursting, regular tonic and polymodal firing. Here we show that the transitions between different firing patterns are often accompanied by a range of chaotic firing, as suggested by an irregular, non-periodic firing pattern. To confirm this, we measure the maximum Lyapunov exponent of the voltage trajectories, and the Lyapunov exponent and Lempel-Ziv's complexity of the ISI time series. The four-variable slow system (without spiking) also generates chaotic behavior, and bifurcation analysis shows that this is often originated by period doubling cascades. Either with or without spikes, chaos is no longer generated when the Ih is removed from the system. As the model is biologically plausible with biophysically meaningful parameters, we propose it as a useful tool to understand chaotic dynamics in neurons. PMID:28344550

  8. Distinct neuroplasticity processes are induced by different periods of acrobatic exercise training.

    PubMed

    Salame, Samira; Garcia, Priscila C; Real, Caroline C; Borborema, Juliana; Mota-Ortiz, Sandra R; Britto, Luiz R G; Pires, Raquel S

    2016-07-15

    Short and long-term physical exercise induce physiological and structural changes in brain motor areas. The relationship between changes of structural and synaptic proteins in brain motor areas and acrobatic exercise is less understood. Our aim was to evaluate the expression of synapsin I (SYS), synaptophysin (SYP), microtubule-associated protein 2 (MAP2), neurofilament (NF), and a marker for recent neuronal activity (Egr-1) in the motor cortex, striatum and cerebellum of adult rats subjected to acrobatic exercise (AE, for 1-4 weeks). We used adult Wistar rats, divided into 4 groups based on duration of acrobatic training, namely 1 week (AE1, n=15), 2 weeks (AE2, n=15), 4 weeks (AE4, n=15), and sedentary (SED, n=15). In AE groups, the rats covered 5 times a circuit that was composed of obstacles, three times a week. The protein levels were analyzed by immunoblotting and immunohistochemistry. The results revealed that short-term AE (AE1 and AE2) induced MAP2 decreases and NF, SYP and Egr-1 increases in the motor cortex; an increase of MAP2, SYS and SYP in the dorsolateral striatum, whereas the dorsomedial striatum showed increased NF, SYS, SYP and Egr-1. Granular cerebellar layer showed increased NF and Egr-1, with increased NF and SYP in the molecular layer. Long-term AE (AE4) promoted an increase of MAP2, SYP and Egr-1 in motor cortex; MAP2, SYS and SYP in the dorsomedial striatum; and NF and Egr-1 in the cerebellar granular layer. In conclusion, our data suggest that different durations of AE induce distinct plastic responses among distinct cortical and subcortical circuits. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Prediction of flow induced sound and vibration of periodically stiffened plates.

    PubMed

    Maxit, Laurent; Denis, Vivien

    2013-01-01

    Stiffened structures excited by the turbulent boundary layer (TBL) occur very frequently in engineering applications; for instance, in the wings of airplanes or the pressure hulls of submarines. To improve knowledge of the interaction between stiffened structures and TBL, this paper deals with the modeling of infinite periodically stiffened plates excited by TBL. The mathematical formulation of the problem is well-established in the literature. The originality of the present work relies on the use of a wavenumber-point reciprocity technique for evaluating the response of the plate to convected harmonic pressure waves. It follows a methodology for estimating the vibro-acoustic response of the plate excited by the TBL from the wall pressure spectrum and its displacements in the wavenumber space due to point excitations located at the receiving positions. The computing process can be reduced to the numerical integration of an analytical expression in the case of a periodically stiffened plate. An application to a naval test case highlights the effect of Bloch-Floquet waves on the vibrations of the plate and its radiated pressure in the fluid.

  10. Magnus-induced dynamics of driven skyrmions on a quasi-one-dimensional periodic substrate

    NASA Astrophysics Data System (ADS)

    Reichhardt, C.; Reichhardt, C. J. Olson

    2016-09-01

    We numerically examine driven skyrmions interacting with a periodic quasi-one-dimensional substrate where the driving force is applied either parallel or perpendicular to the substrate periodicity direction. For perpendicular driving, the particles in a purely overdamped system simply slide along the substrate minima; however, for skyrmions where the Magnus force is relevant, we find that a rich variety of dynamics can arise. In the single skyrmion limit, the skyrmion motion is locked along the driving or longitudinal direction for low drives, while at higher drives a transition occurs to a state in which the skyrmion moves both transverse and longitudinal to the driving direction. Within the longitudinally locked phase we find a pronounced speedup effect that occurs when the Magnus force aligns with the external driving force, while at the transition to transverse and longitudinal motion, the skyrmion velocity drops, producing negative differential conductivity. For collectively interacting skyrmion assemblies, the speedup effect is still present and we observe a number of distinct dynamical phases, including a sliding smectic phase, a disordered or moving liquid phase, a moving hexatic phase, and a moving crystal phase. The transitions between the dynamic phases produce distinct features in the structure of the skyrmion lattice and in the velocity-force curves. We map these different phases as a function of the ratio of the Magnus term to the dissipative term, the substrate strength, the commensurability ratio, and the magnitude of the driving force.

  11. Periodic oscillation and fine structure of wedge-induced oblique detonation waves

    NASA Astrophysics Data System (ADS)

    Gui, Ming-Yue; Fan, Bao-Chun; Dong, Gang

    2011-12-01

    An oblique detonation wave for a Mach 7 inlet flow over a long enough wedge of 30° turning angle is simulated numerically using Euler equation and one-step rection model. The fifth-order WENO scheme is adopted to capture the shock wave. The numerical results show that with the compression of the wedge wall the detonation wave front structure is divided into three sections: the ZND model-like strcuture, single-sided triple point structure and dual-headed triple point strucuture. The first structure is the smooth straight, and the second has the characteristic of the triple points propagating dowanstream only with the same velocity, while the dual-headed triple point structure is very complicated. The detonation waves facing upstream and downstream propagate with different velocities, in which the periodic collisions of the triple points cause the oscillation of the detonation wave front. This oscillation process has temporal and spatial periodicity. In addition, the triple point trace are recorded to obtain different cell structures in three sections.

  12. Mechanical buckling induced periodic kinking/stripe microstructures in mechanically peeled graphite flakes from HOPG

    NASA Astrophysics Data System (ADS)

    Ren, Manrui; Liu, Ze; Zheng, Quan-shui; Liu, Jefferson Zhe

    2015-08-01

    Mechanical exfoliation is a widely used method to isolate high quality graphene layers from bulk graphite. In our recent experiments, some ordered microstructures, consisting of a periodic alternation of kinks and stripes, were observed in thin graphite flakes that were mechanically peeled from highly oriented pyrolytic graphite. In this paper, a theoretical model is presented to attribute the formation of such ordered structures to the alternation of two mechanical processes during the exfoliation: (1) peeling of a graphite flake and (2) mechanical buckling of the flake being subjected to bending. In this model, the width of the stripes L is determined by thickness h of the flakes, surface energy , and critical buckling strain . Using some appropriate values of and that are within the ranges determined by other independent experiments and simulations, the predicted relations between the stripe width and the flake thickness agree reasonably well with our experimental measurements. Conversely, measuring the L- h relations of the periodic microstructures in thin graphite flakes could help determine the critical mechanical buckling strain and the interface energy.

  13. Design of co-existence parallel periodic surface structure induced by picosecond laser pulses on the Al/Ti multilayers

    NASA Astrophysics Data System (ADS)

    Petrović, Suzana; Peruško, D.; Kovač, J.; Panjan, P.; Mitrić, M.; Pjević, D.; Kovačević, A.; Jelenković, B.

    2017-09-01

    Formation of periodic nanostructures on the Ti/5x(Al/Ti)/Si multilayers induced by picosecond laser pulses is studied in order to better understand the formation of a laser-induced periodic surface structure (LIPSS). At fluence slightly below the ablation threshold, the formation of low spatial frequency-LIPSS (LSFL) oriented perpendicular to the direction of the laser polarization is observed on the irradiated area. Prolonged irradiation while scanning results in the formation of a high spatial frequency-LIPSS (HSFL), on top of the LSFLs, creating a co-existence parallel periodic structure. HSFL was oriented parallel to the incident laser polarization. Intermixing between the Al and Ti layers with the formation of Al-Ti intermetallic compounds was achieved during the irradiation. The intermetallic region was formed mostly within the heat affected zone of the sample. Surface segregation of aluminium with partial ablation of the top layer of titanium was followed by the formation of an ultra-thin Al2O3 film on the surface of the multi-layered structure.

  14. The formation mechanism and evolution of ps-laser-induced high-spatial-frequency periodic surface structures on titanium

    NASA Astrophysics Data System (ADS)

    Pan, A. F.; Wang, W. J.; Mei, X. S.; Yang, H. Z.; Sun, X. F.

    2017-01-01

    We report the formation and evolution mechanisms of HSFLs (high-spatial-frequency laser-induced periodic surface structures) on the commercial pure titanium under 10-ps 532-nm-wavelength laser irradiation. At a lower peak laser fluence, HSFLs in the rough zone are first formed along the surface texture. Subsequently, HSFLs in the flat zone are formed with an orientation parallel to the laser polarization direction. The formation of HSFLs can be attributed to the parallel orientation of the initial periodic modulation of the electron plasma concentration to the laser polarization direction. In particular, the formation of HSFLs along the surface texture occurs because the absorbed laser energy density is along the surface texture. At a higher peak laser fluence, two types of HSFLs appear together with LSFLs. The first type involves HSFLs that initially cover the concave part of the LSFL (low-spatial-frequency laser-induced periodic surface structures) and penetrate inward as the number of spot overlaps increases. This formation mechanism can be attributed to cavitation instability. The second type involves HSFLs that are initially in the convex part of the LSFL, and they are transformed into oxidized nanodots as the number of spot overlaps increases. The oxidized nanodots increase the absorption of laser energy in titanium, which leads to the ablation and removal of the oxidized material. Therefore, the surface of the LSFL becomes smooth.

  15. Gas Exchange and Phytoluminography of Single Red Kidney Bean Leaves during Periods of Induced Stomatal Oscillations

    PubMed Central

    Ellenson, James L.; Raba, Richard M.

    1983-01-01

    This report examines the capabilities of a new approach to the study of gas exchange and electron transport properties of single, intact leaves. The method combines conventional aspects of analysis with an image intensification system that records the spatial distribution of delayed light emission (DLE) over single leaf surfaces. The combined system was used to investigate physiological perturbations induced by exposure of single leaves of Phaseolus vulgaris cv `California Light Red' to a combination of SO2 (0.5 microliters per liter) and ozone (0.1 microliters per liter). Exposure of one-half of a leaf to this combination induced DLE and stomatal oscillations, but only in the half of the leaf exposed to the combined gases. Examination of phytoluminographs taken during these oscillations revealed distinct leaf patches where the greatest changes in DLE intensity occurred. This phenomenon is interpreted to be evidence that control of stomatal activity of intact plant leaves occurs within discrete leaf areas defined within the vascular network. Images Fig. 6 PMID:16662989

  16. Oxidative stress, biochemical alterations, and hyperlipidemia in female rats induced by lead chronic toxicity during puberty and post puberty periods

    PubMed Central

    Alya, Annabi; Ines, Dhouib Bini; Montassar, Lasram; Najoua, Gharbi; Saloua, El Fazâa

    2015-01-01

    Objective(s): Lead (Pb) is a toxic metal inducing many destructive effects leading to a broad range of physiological, biochemical, and neurological dysfunctions in humans and laboratory animals. Materials and Methods: Here, we investigated the effect of chronic exposure to Pb (50 mg/l) on oxidative stress, hepatotoxicity, nephrotoxicity, and lipid profile of two different age groups of female rats treated with Pb from delivery until puberty period (40 days, Pb40) and post puberty period (65 days, Pb65). Results: Our results clearly show that the administration of Pb produces oxidative damage in liver and kidney, as strongly suggested by the significant increase in TBARS, decrease in total SH, and the alteration of SOD activity. Elevation in liver function biomarkers, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and reduction in total protein (liver and plasma) and albumin are evidence of perturbations of liver synthetic function. In young Pb-treated group, Pb-induced nephropathy was more pronounced by the increase in the levels of creatinine, urea, and uric acid. However, hyperlipidemia was evident for both Pb-exposed groups leading to a potential risk for cardiovascular diseases and atherosclerosis. Conclusion: It is concluded that Pb induces metabolic and oxidative disturbances depending on the age of the animals, which are not negligible. PMID:26730340

  17. Vibration attenuations induced by periodic arrays of piezoelectric patches connected by enhanced resonant shunting circuits

    NASA Astrophysics Data System (ADS)

    Wang, Gang; Wang, Jianwei; Chen, Shengbing; Wen, Jihong

    2011-12-01

    Periodic arrays of piezoelectric patches connected by enhanced resonant shunting circuits are attached to a slender beam to control the propagation of vibration. Numerical models based on the transfer matrix methodology are constructed to predict the band structure, attenuation factors and the transmission of vibration in the proposed smart structure. The vibration attenuations of the proposed smart structure and that with the passive resonant shunting circuits are compared in order to verify the efficiency of the enhanced resonant shunting circuits. Vibration experiments are conducted in order to validate the theoretical predictions. The specimen with a combination of different types of resonant shunting circuits is also studied in order to gain wider attenuation frequency ranges.

  18. Formation of laser induced periodic surface structures (LIPSS) on Ti upon double fs pulse exposure

    NASA Astrophysics Data System (ADS)

    Gemini, Laura; Hashida, Masaki; Nishii, Takaya; Miyasaka, Yasuhiro; Inoue, Shunsuke; Limpouch, Jiri; Mocek, Tomas; Sakabe, Shuji

    2015-03-01

    Recently a parametric decay model was proposed in order to foresee LIPSS interspaces, and experimental results are in reasonable agreement. To confirm the possibility assumed by the model of pre-formed plasma generation, Ti surface was irradiated by a femtosecond (fs) laser beam composed by double fs pulses, with a fixed delay of 160 fs. The fluence of the first pulse (FPP), responsible for surface plasma formation, was varied in the range 10-50 mJ cm-2 and always kept below the LIPSS formation threshold fluence (FLIPSS) of Ti for 50-single-shots exposure. The fluence of the delayed pulse (FLP), responsible for LIPSS formation, was varied in the range 60-150 mJ cm-2 and always kept above FLIPSS. Regardless the specific fluence FLP of the delayed pulse, the interspace of the grating structures increases with the increase of FPP, that is the increase of the surface plasma density. This tendency suggests that a variation of the surface plasma density, due to a variation of FPP, actually leads to a modification of the grating features, highlighting the driving role of the first pulse in LIPSS formation. Moreover, we observed that the LIPSS periodicities after double pulse exposures are in quite good agreement with data on LIPSS periodicities after single 160 fs pulse irradiations on Ti surface and with the curve predicted by the parametric decay model. This experimental result suggests that the preformed plasma might be produced in the rising edge of the temporal profile of the laser pulse.

  19. Formation of laser-induced periodic surface structures (LIPSS) on tool steel by multiple picosecond laser pulses of different polarizations

    NASA Astrophysics Data System (ADS)

    Gregorčič, Peter; Sedlaček, Marko; Podgornik, Bojan; Reif, Jürgen

    2016-11-01

    Laser-induced periodic surface structures (LIPSS) are produced on cold work tool steel by irradiation with a low number of picosecond laser pulses. As expected, the ripples, with a period of about 90% of the laser wavelength, are oriented perpendicular to the laser polarization. Subsequent irradiation with the polarization rotated by 45° or 90° results in a corresponding rotation of the ripples. This is visible already with the first pulse and becomes almost complete - erasing the previous orientation - after as few as three pulses. The phenomenon is not only observed for single-spot irradiation but also for writing long coherent traces. The experimental results strongly defy the role of surface plasmon-polaritons as the predominant key to LIPSS formation.

  20. Quasi-periodic behaviour in a model for the lithium-induced, electrical oscillations of frog skin.

    PubMed

    Letellier, Christophe; Lassalles, Jean-Paul; Norris, Vic; Ripoll, Camille; Thellier, Michel

    2002-09-01

    The fact that oscillations can be induced in studies of the maintenance of the electrical potential of frog skin by addition of lithium allowed evaluation of several parameters fundamental to the functioning of the system in vivo (e.g. relative volumes of internal compartments, characteristic times of ionic exchanges between compartments). A realistic model was thus proposed under the form of a set of ordinary differential equations. In the past, numerical simulations using such a model reproduced the periodic experimental oscillations and was able to provide an explanation for the global synchronised oscillations of the whole skin. In that paper, new numerical simulations reproduce the non-periodic oscillations which were observed two decades ago, but not reproduced by the model. Moreover, the dynamical process under which all the local oscillators are synchronised is explained in terms of a tangent bifurcation.

  1. First principles simulation of laser-induced periodic surface structure using the particle-in-cell method

    NASA Astrophysics Data System (ADS)

    Mitchell, Robert A.; Schumacher, Douglass W.; Chowdhury, Enam A.

    2015-11-01

    We present our results of a fundamental simulation of a periodic grating structure formation on a copper target during the femtosecond-pulse laser damage process, and compare our results to recent experiment. The particle-in-cell (PIC) method is used to model the initial laser heating of the electrons, a two-temperature model (TTM) is used to model the thermalization of the material, and a modified PIC method is employed to model the atomic transport leading to a damage crater morphology consistent with experimental grating structure formation. This laser-induced periodic surface structure (LIPSS) is shown to be directly related to the formation of surface plasmon polaritons (SPP) and their interference with the incident laser pulse.

  2. Investigating the potential of Tamarindus indica pectin-chitosan conjugate for reducing recovery period in TNBS induced colitis.

    PubMed

    Sethi, Sheshank; Khurana, Rajneet Kaur; Kamboj, Sunil; Sharma, Radhika; Singh, Akashdeep; Rana, Vikas

    2017-05-01

    The present study was aimed at exploiting the wound healing applications and tablet coating potential of Tamarindus indica pectin-chitosan (PCH) conjugate for reducing recovery period from TNBS induced colitis. The PCH (60:40, 3% w/v) solution when spray coated followed by drying at 50°C created hydrophobic surface, that may be due to interaction of pectin with chitosan as evident from temperature ramping rheological investigations. Further, the 15% w/v coating was sufficient to prevent Mesalamine (Ma) release in pH 1.2. The AUC and AUMC of PCH coated tablets were 1.98 and 17.69 fold increased as compared to uncoated tablets. A synergistic therapeutic effect of PCH conjugate with Ma was evident from the colon/body weight ratio, clinical activity and damage score. Overall, the findings suggested PCH and Ma (20mg) reduces the recovery period from 5 to 4days with reduction in dose.

  3. Periodic density-functional calculations on work-function change induced by adsorption of halogens on Cu(111).

    PubMed

    Roman, Tanglaw; Groß, Axel

    2013-04-12

    Using periodic density-functional theory calculations, we address the work-function change induced by the adsorption of chlorine and iodine on Cu(111) which are shown to change the work function in opposite ways, contrary to what one may expect for these two electron acceptors. In contrast to previous studies, we demonstrate that substrate effects play only a minor role in work-function changes brought about by halogen adsorption on metals. Instead, polarization on the adsorbate not only explains the sign of the work-function change as a contributor to a positive surface dipole moment, but it is also the decisive factor in the dependence of adsorption-induced work-function changes on the coverage of halogens on metal surfaces.

  4. Laser-induced periodic surface structures formation on mesoporous silicon from nanoparticles produced by picosecond and femtosecond laser shots

    NASA Astrophysics Data System (ADS)

    Talbi, Abderazek; Kaya-Boussougou, Sostaine; Sauldubois, Audrey; Stolz, Arnaud; Boulmer-Leborgne, Chantal; Semmar, Nadjib

    2017-07-01

    This paper deals with the formation of laser-induced periodic surface structures (LIPSS) on mesoporous silicon thin films induced by two laser regimes in the UV range: picosecond and femtosecond. Different LIPSS formation mechanisms from nanoparticles, mainly coalescence and agglomeration, have been evidenced by scanning electron microscopy analysis. The apparition of a liquid phase during both laser interaction at low fluence (20 mJ/cm2) and after a large number of laser pulses (up to 12,000) has been also shown with 100 nm size through incubation effect. Transmission electron microscopy analyses have been conducted to investigate the molten phase structures below and inside LIPSS. Finally, it has shown that LIPSS are composed of amorphous silicon when mesoporous silicon is irradiated by laser beam in both regimes. Nevertheless, mesoporous silicon located between LIPSS stays crystallized.

  5. Determinants of HIV-induced brain changes in three different periods of the early clinical course: A data mining analysis.

    PubMed

    Cao, Bokai; Kong, Xiangnan; Kettering, Casey; Yu, Philip; Ragin, Ann

    2015-01-01

    To inform an understanding of brain status in HIV infection, quantitative imaging measurements were derived at structural, microstructural and macromolecular levels in three different periods of early infection and then analyzed simultaneously at each stage using data mining. Support vector machine recursive feature elimination was then used for simultaneous analysis of subject characteristics, clinical and behavioral variables, and immunologic measures in plasma and CSF to rank features associated with the most discriminating brain alterations in each period. The results indicate alterations beginning in initial infection and in all periods studied. The severity of immunosuppression in the initial virus host interaction was the most highly ranked determinant of earliest brain alterations. These results shed light on the initial brain changes induced by a neurotropic virus and their subsequent evolution. The pattern of ongoing alterations occurring during and beyond the period in which virus is suppressed in the systemic circulation supports the brain as a viral reservoir that may preclude eradication in the host. Data mining capabilities that can address high dimensionality and simultaneous analysis of disparate information sources have considerable utility for identifying mechanisms underlying onset of neurological injury and for informing new therapeutic targets.

  6. Tunable wavelength erbium doped fiber linear cavity laser based on mechanically induced long-period fiber gratings

    NASA Astrophysics Data System (ADS)

    Pérez Maciel, M.; Montenegro Orenday, J. A.; Estudillo Ayala, J. M.; Jáuregui-Vázquez, D.; Sierra-Hernandez, J. M.; Hernandez-Garcia, J. C.; Rojas-Laguna, R.

    2016-09-01

    Tunable wavelength erbium doped fiber linear cavity laser, based on mechanically induced long-period fiber gratings (MLPFG) is presented. The laser was tuned applying pressure over the MLPFG, in order to monitor this, pressure is applied over a plate with periodic grooves that has a short length, this pressure is controlled by a digital torque tester as a result tunable effect is observed. The grooves have a period of 620µm and the maximal pressure without breakpoint fiber is around 0.80lb-in2. Furthermore, the MLPFG used can be erased, reconfigured and exhibit a transmission spectra with termal stability, similar to high cost photoinduced long period gratings. In this work, by pressure increment distributed over the MLPFG from 0.40 lb-in2 to 0. 70 lb-in 2, tuned operation range of 14nm was observed and single line emission was tuned in the C telecommunication band. According to the stability analysis the signal to noise ratio was 29 dB and minimal wavelength oscillations of 0.29nm.

  7. A tunable wavelength erbium doped fiber ring laser based on mechanically induced long-period fiber gratings

    NASA Astrophysics Data System (ADS)

    Pérez Maciel, M.; López Dieguez, Y.; Montenegro Orenday, J. A.; Jáuregui Vázquez, D.; Sierra Hernández, J. M.; Huerta Masscote, E. H.; Rojas Laguna, R.; Estudillo Ayala, J. M.

    2015-08-01

    A tunable wavelength erbium doped fiber ring laser, based on mechanically induced long-period fiber gratings (MLPFG) is presented. The laser was tuned applying pressure over the MLPFG, in order to control this, pressure is applied over a plate with periodic grooves that has a short length, this pressure is applied by a digital torque tester, as a result tunable effect is observed. The grooves have a period of 630μm and the maximal pressure without breakpoint fiber is around 0.80lb-in2. Furthermore, the MLPFG used can be erased, reconfigured and exhibit a transmission spectra with thermal stability, similar to high cost photoinduced long period gratings. In this work, by pressure increment distributed over the MLPFG from 0.20 lb-in2 to 0.50 lb-inμ, tuned operation range of 10nm was observed and single line emission was tuned between C and L telecommunications bands. According to the stability analysis the signal to noise ratio and linewidth observed were 35dB and 0.2nm respectively.

  8. Laser-induced periodic structures for light extraction efficiency enhancement of GaN-based light emitting diodes.

    PubMed

    Chen, Jiun-Ting; Lai, Wei-Chih; Kao, Yu-Jui; Yang, Ya-Yu; Sheu, Jinn-Kong

    2012-02-27

    The laser-induced periodic surface structure technique was used to form simultaneously dual-scale rough structures (DSRS) with spiral-shaped nanoscale structure inside semi-spherical microscale holes on p-GaN surface to improve the light-extraction efficiency of light-emitting diodes (LEDs). The light output power of DSRS-LEDs was 30% higher than that of conventional LEDs at an injection current of 20 mA. The enhancement in the light output power could be attributed to the increase in the probability of photons to escape from the increased surface area of textured p-GaN surface.

  9. Optically induced excitonic electroabsorption in a periodically delta-doped InGaAs/GaAs multiple quantum well structure

    NASA Technical Reports Server (NTRS)

    Larsson, A.; Maserjian, J.

    1991-01-01

    Large optically induced Stark shifts have been observed in a periodically delta-doped InGaAs/GaAs multiple quantum well structure. With an excitation intensity of 10 mW/sq cm, an absolute quantum well absorption change of 7000/cm was measured with a corresponding differential absorption change as high as 80 percent. The associated maximum change in the quantum well refractive index is 0.04. This material is promising for device development for all-optical computing and signal processing.

  10. Influence of crystal orientation on the formation of femtosecond laser-induced periodic surface structures and lattice defects accumulation

    SciTech Connect

    Sedao, Xxx; Garrelie, Florence Colombier, Jean-Philippe; Reynaud, Stéphanie; Pigeon, Florent; Maurice, Claire; Quey, Romain

    2014-04-28

    The influence of crystal orientation on the formation of femtosecond laser-induced periodic surface structures (LIPSS) has been investigated on a polycrystalline nickel sample. Electron Backscatter Diffraction characterization has been exploited to provide structural information within the laser spot on irradiated samples to determine the dependence of LIPSS formation and lattice defects (stacking faults, twins, dislocations) upon the crystal orientation. Significant differences are observed at low-to-medium number of laser pulses, outstandingly for (111)-oriented surface which favors lattice defects formation rather than LIPSS formation.

  11. Observation of Geometric Parametric Instability Induced by the Periodic Spatial Self-Imaging of Multimode Waves

    NASA Astrophysics Data System (ADS)

    Krupa, Katarzyna; Tonello, Alessandro; Barthélémy, Alain; Couderc, Vincent; Shalaby, Badr Mohamed; Bendahmane, Abdelkrim; Millot, Guy; Wabnitz, Stefan

    2016-05-01

    Spatiotemporal mode coupling in highly multimode physical systems permits new routes for exploring complex instabilities and forming coherent wave structures. We present here the first experimental demonstration of multiple geometric parametric instability sidebands, generated in the frequency domain through resonant space-time coupling, owing to the natural periodic spatial self-imaging of a multimode quasi-continuous-wave beam in a standard graded-index multimode fiber. The input beam was launched in the fiber by means of an amplified microchip laser emitting sub-ns pulses at 1064 nm. The experimentally observed frequency spacing among sidebands agrees well with analytical predictions and numerical simulations. The first-order peaks are located at the considerably large detuning of 123.5 THz from the pump. These results open the remarkable possibility to convert a near-infrared laser directly into a broad spectral range spanning visible and infrared wavelengths, by means of a single resonant parametric nonlinear effect occurring in the normal dispersion regime. As further evidence of our strong space-time coupling regime, we observed the striking effect that all of the different sideband peaks were carried by a well-defined and stable bell-shaped spatial profile.

  12. Polarization induced Z2 and Chern topological phases in a periodically driving field

    NASA Astrophysics Data System (ADS)

    Pi, Shu-Ting; Savrasov, Sergey

    2016-03-01

    Z2 and Chern topological phases such as newly discovered quantum spin Hall and original quantum Hall states hardly both co–exist in a single material due to their contradictory requirement on the time–reversal symmetry (TRS). We show that although the TRS is broken in systems with a periodically driving field, an effective TRS can still be defined provided the ac–field is linearly polarized or certain other conditions are satisfied. The controllable TRS provides us a route to manipulate contradictory phases by tuning the polarization. To demonstrate the idea, we consider a tight-binding model that is relevant to several monolayered materials as a benchmark system. Our calculation shows not only topological Z2 to Chern phase transition occurs but rich Chern phases are also observed. In addition, we also discussed the realization of our proposal in real materials, such as spin-orbit coupled graphene and crystal Bismuth. This opens the possibility of manipulating various topological phases in a single material and can be a promising approach to engineer new electronic states of matter.

  13. Tyramine-modified pectins via periodate oxidation for soybean hull peroxidase induced hydrogel formation and immobilization.

    PubMed

    Prokopijevic, Milos; Prodanovic, Olivera; Spasojevic, Dragica; Kovacevic, Gordana; Polovic, Natalija; Radotic, Ksenija; Prodanovic, Radivoje

    2017-03-01

    Pectin was modified by oxidation with sodium periodate at molar ratios of 2.5, 5, 10, 15 and 20 mol% and reductive amination with tyramine and sodium cyanoborohydride afterwards. Concentration of tyramine groups within modified pectin ranged from 54.5 to 538 μmol/g of dry pectin while concentration of ionizable groups ranged from 3.0 to 4.0 mmol/g of dry polymer compared to 1.5 mmol/g before modification due to the introduction of amino group. All tyramine-pectins showed exceptional gelling properties and could form hydrogel both by cross-linking of carboxyl groups with calcium or by cross-linking phenol groups with peroxidase in the presence of hydrogen peroxide. These hydrogels were tested as carriers for soybean hull peroxidase (SHP) immobilization within microbeads formed in an emulsion based enzymatic polymerization reaction. SHP immobilized within tyramine-pectin microbeads had an increased thermal and organic solvent stability compared to the soluble enzyme. Immobilized SHP was more active in acidic pH region and had slightly decreased K m value of 2.61 mM compared to the soluble enzyme. After 7 cycles of repeated use in batch reactor for pyrogallol oxidation microbeads, immobilized SHP retained half of the initial activity.

  14. Real-time analysis of arc-induced Long Period Gratings under gamma irradiation

    PubMed Central

    Esposito, Flavio; Ranjan, Rajeev; Stăncălie, Andrei; Sporea, Dan; Neguţ, Daniel; Becherescu, Nicu; Campopiano, Stefania; Iadicicco, Agostino

    2017-01-01

    In this paper, we present a comparative experimental and theoretical study on gamma radiation sensitivity of Long Period Gratings (LPGs), fabricated by electric arc discharge technique, as monitored in three single mode optical fibers supplied by different manufacturers. A real-time measurement of LPGs’ wavelength shift was performed until a total dose of 35 kGy was reached, with average dose rate of 0.18 kGy/h, the irradiation being done at room temperature. In one case, a maximum radiation sensitivity of 1.34 nm/kGy was recorded for doses up to 0.5 kGy. Moreover, by combining experimental results with numerical simulations, it was found that changes occurred in the core refractive index of the irradiated optical fibers up to 2.5 ∙ 10−5. The increase of the core thermo-optic coefficient up to 1.5 ∙ 10−8/°C was observed as well. PMID:28262784

  15. Fully distributed fiber-optic sensing based on acoustically induced long-period grating

    NASA Astrophysics Data System (ADS)

    Wang, Dorothy Y.; Wang, Yunmiao; Han, Ming; Gong, Jianmin; Wang, Anbo

    2011-05-01

    This paper gives a review of a proposed fully-distributed fiber-optic sensing technique based on a traveling long-period grating (LPG) in a single-mode optical fiber. The LPG is generated by pulsed acoustic waves that propagate along the fiber. Based on this platform, first we demonstrated the fully-distributed temperature measurement in a 2.5m fiber. Then by coating the fiber with functional coatings, we demonstrated fully-distributed biological and chemical sensing. In the biological sensing experiment, immunoglobulin G (IgG) was immobilized onto the fiber surface, and we showed that only specific antigen-antibody binding can introduce a measurable shift in the transmission optical spectrum of the traveling LPG when it passes through the pretreated fiber segment. In the hydrogen sensing experiment, the fiber was coated with a platinum (Pt) catalyst layer, which is heated by the thermal energy released from Pt-assisted combustion of H2 and O2, and the resulted temperature change gives rise to a measurable LPG wavelength shift when the traveling LPG passes through. Hydrogen concentration from 1% to 3.8% was detected in the experiment. This technique may also permit measurement of other quantities by changing the functional coating on the fiber; therefore it is expected to be capable of other fully-distributed sensing applications.

  16. Real-time analysis of arc-induced Long Period Gratings under gamma irradiation

    NASA Astrophysics Data System (ADS)

    Esposito, Flavio; Ranjan, Rajeev; Stăncălie, Andrei; Sporea, Dan; Neguţ, Daniel; Becherescu, Nicu; Campopiano, Stefania; Iadicicco, Agostino

    2017-03-01

    In this paper, we present a comparative experimental and theoretical study on gamma radiation sensitivity of Long Period Gratings (LPGs), fabricated by electric arc discharge technique, as monitored in three single mode optical fibers supplied by different manufacturers. A real-time measurement of LPGs’ wavelength shift was performed until a total dose of 35 kGy was reached, with average dose rate of 0.18 kGy/h, the irradiation being done at room temperature. In one case, a maximum radiation sensitivity of 1.34 nm/kGy was recorded for doses up to 0.5 kGy. Moreover, by combining experimental results with numerical simulations, it was found that changes occurred in the core refractive index of the irradiated optical fibers up to 2.5 • 10‑5. The increase of the core thermo-optic coefficient up to 1.5 • 10‑8/°C was observed as well.

  17. Polarization induced Z2 and Chern topological phases in a periodically driving field.

    PubMed

    Pi, Shu-Ting; Savrasov, Sergey

    2016-03-11

    Z2 and Chern topological phases such as newly discovered quantum spin Hall and original quantum Hall states hardly both co-exist in a single material due to their contradictory requirement on the time-reversal symmetry (TRS). We show that although the TRS is broken in systems with a periodically driving field, an effective TRS can still be defined provided the ac-field is linearly polarized or certain other conditions are satisfied. The controllable TRS provides us a route to manipulate contradictory phases by tuning the polarization. To demonstrate the idea, we consider a tight-binding model that is relevant to several monolayered materials as a benchmark system. Our calculation shows not only topological Z2 to Chern phase transition occurs but rich Chern phases are also observed. In addition, we also discussed the realization of our proposal in real materials, such as spin-orbit coupled graphene and crystal Bismuth. This opens the possibility of manipulating various topological phases in a single material and can be a promising approach to engineer new electronic states of matter.

  18. Polarization induced Z2 and Chern topological phases in a periodically driving field

    PubMed Central

    Pi, Shu-Ting; Savrasov, Sergey

    2016-01-01

    Z2 and Chern topological phases such as newly discovered quantum spin Hall and original quantum Hall states hardly both co–exist in a single material due to their contradictory requirement on the time–reversal symmetry (TRS). We show that although the TRS is broken in systems with a periodically driving field, an effective TRS can still be defined provided the ac–field is linearly polarized or certain other conditions are satisfied. The controllable TRS provides us a route to manipulate contradictory phases by tuning the polarization. To demonstrate the idea, we consider a tight-binding model that is relevant to several monolayered materials as a benchmark system. Our calculation shows not only topological Z2 to Chern phase transition occurs but rich Chern phases are also observed. In addition, we also discussed the realization of our proposal in real materials, such as spin-orbit coupled graphene and crystal Bismuth. This opens the possibility of manipulating various topological phases in a single material and can be a promising approach to engineer new electronic states of matter. PMID:26965181

  19. Recirculation zones induce non-Fickian transport in three-dimensional periodic porous media

    NASA Astrophysics Data System (ADS)

    Crevacore, Eleonora; Tosco, Tiziana; Sethi, Rajandrea; Boccardo, Gianluca; Marchisio, Daniele L.

    2016-11-01

    In this work, the influence of pore space geometry on solute transport in porous media is investigated performing computational fluid dynamics pore-scale simulations of fluid flow and solute transport. The three-dimensional periodic domains are obtained from three different pore structure configurations, namely, face-centered-cubic (fcc), body-centered-cubic (bcc), and sphere-in-cube (sic) arrangements of spherical grains. Although transport simulations are performed with media having the same grain size and the same porosity (in fcc and bcc configurations), the resulting breakthrough curves present noteworthy differences, such as enhanced tailing. The cause of such differences is ascribed to the presence of recirculation zones, even at low Reynolds numbers. Various methods to readily identify recirculation zones and quantify their magnitude using pore-scale data are proposed. The information gained from this analysis is then used to define macroscale models able to provide an appropriate description of the observed anomalous transport. A mass transfer model is applied to estimate relevant macroscale parameters (hydrodynamic dispersion above all) and their spatial variation in the medium; a functional relation describing the spatial variation of such macroscale parameters is then proposed.

  20. Does status epilepticus induced at early postnatal period change excitability after cortical epileptic afterdischarges?

    PubMed

    Mareš, Pavel; Kubová, Hana

    2016-08-01

    Possible changes of cortical excitability after status epilepticus (SE) elicited in 12-day-old rats were studied by means of paired cortical afterdischarges (ADs). Consequences of lithium-pilocarpine status were studied in animals with implanted electrodes 3, 6, 9, 13, and 26 days after SE. Paired low-frequency stimulation with a 1-min interval was repeated after 10 min, and duration of ADs was measured. Control rats received saline instead of pilocarpine; other treatments were the same as in SE group. Postictal refractoriness (i.e., the testing response significantly shorter than the conditioning one) appeared at the age of 18 days in lithium-paraldehyde controls, whereas SE animals exhibited this phenomenon since postnatal day 21. The only significant difference between SE and lithium-paraldehyde controls was found in the second conditioning AD in the oldest group studied-it was longer in 38-day-old SE animals. Our results demonstrated moderate signs of higher excitability of SE rats in comparison with control ones long before appearance of spontaneous seizures. Wiley Periodicals, Inc. © 2016 International League Against Epilepsy.

  1. Dynamic conversion of optical modes in magnetic garnet films induced by resonances of periodic stripe domains

    NASA Astrophysics Data System (ADS)

    Winkler, H. P.; Doetsch, H.; Luehrmann, B.; Sure, S.

    1994-09-01

    Magnetic garnet films of composition (Y,Bi)3(Fe,Al)5O12 are grown by liquid phase epitaxy on (111) oriented substrates of Gd3Ga5O12. They support periodic lattices of parallel stripe domains. A simple strip antenna is used to excite the domain wall resonance and the two branches of the domain resonance in the frequency range up to 5 GHz. The resonance frequencies and the dynamic components of the magnetization are calculated using a hybridization model. Good agreement between calculated and measured resonance frequencies is obtained if the quality factor of the film is larger than 0.6. Optical modes are coupled into the waveguiding film. The excited domain resonances cause dynamic conversion of transverse electric and transverse magnetic modes by the Faraday and the Cotton-Mouton effects. Mode coupling and conversion are calculated by the perturbation theory. The dynamic conversion efficiencies are measured at the fundamental and the first harmonic frequency and at zero diffraction order as a function of the static induction applied in the film plane parallel to the stripes. Conversion efficiencies up to 18% are achieved at a frequency of 2.8 GHz. From the experimental data the precession angles are derived.

  2. Recirculation zones induce non-Fickian transport in three-dimensional periodic porous media.

    PubMed

    Crevacore, Eleonora; Tosco, Tiziana; Sethi, Rajandrea; Boccardo, Gianluca; Marchisio, Daniele L

    2016-11-01

    In this work, the influence of pore space geometry on solute transport in porous media is investigated performing computational fluid dynamics pore-scale simulations of fluid flow and solute transport. The three-dimensional periodic domains are obtained from three different pore structure configurations, namely, face-centered-cubic (fcc), body-centered-cubic (bcc), and sphere-in-cube (sic) arrangements of spherical grains. Although transport simulations are performed with media having the same grain size and the same porosity (in fcc and bcc configurations), the resulting breakthrough curves present noteworthy differences, such as enhanced tailing. The cause of such differences is ascribed to the presence of recirculation zones, even at low Reynolds numbers. Various methods to readily identify recirculation zones and quantify their magnitude using pore-scale data are proposed. The information gained from this analysis is then used to define macroscale models able to provide an appropriate description of the observed anomalous transport. A mass transfer model is applied to estimate relevant macroscale parameters (hydrodynamic dispersion above all) and their spatial variation in the medium; a functional relation describing the spatial variation of such macroscale parameters is then proposed.

  3. Effect of convective disturbances induced by g-jitter on the periodic precipitation of lysozyme.

    PubMed

    Lappa, M; Carotenuto, L

    2003-01-01

    Numerical simulations are carried out to investigate the crystallization process of a protein macromolecular substance under two different conditions: pure diffusive regime and microgravity conditions present on space laboratories. The configuration under investigation consists of a protein reactor and a salt chamber separated by an "interface". The interface is strictly related to the presence of agarose gel in one of the two chambers. Sedimentation and convection under normal gravity conditions are prevented by the use of gel in the protein chamber (pure diffusive regime). Under microgravity conditions periodic time-dependent accelerations (g-jitter) are taken into account. Novel mathematical models are introduced to simulate the complex phenomena related to protein nucleation and further precipitation (or resolution) according to the concentration distribution and in particular to simulate the motion of the crystals due to g-litter in the microgravity environment. The numerical results show that gellified lysozyme (crystals "locked"on the matrix of agarose gel) precipitates to produce "spaced deposits". The crystal formation results modulated in time and in space (Liesegang patterns), due to the non-linear interplay among transport, crystal nucleation and growth. The propagation of the nucleation front is characterized by a wave-like behavior. In microgravity conditions (without gel), g-jitter effects act modifying the phenomena with respect to the on ground gellified configuration. The role played by the direction of the applied sinusoidal acceleration with respect to the imposed concentration gradient (parallel or perpendicular) is investigated. It has a strong influence on the dynamic behaviour of the depletion zones and on the spatial distribution of the crystals. Accordingly the possibility to obtain better crystals for diffraction analyses is discussed.

  4. In situ probing of pulsed laser melting and laser-induced periodic surface structures formation by dynamic reflectivity

    NASA Astrophysics Data System (ADS)

    Huynh, T. T. D.; Semmar, N.

    2017-09-01

    The melting process and nanostructure formation induced by nanosecond and picosecond laser pulses on bulk silicon and copper thin film were studied by ex situ analysis and in situ real time reflectivity. Three different probing wavelengths (633, 473 and 326 nm) were used during the pump laser processing and were correlated to the beam parameters (pulse duration, laser fluence and number of laser shots) and copper thin film thickness. On a silicon surface using a KrF laser beam (27 ns, 1 Hz, 248 nm), the melting threshold was determined close to 700 mJ cm‑2 and the melting duration increased from 10 to 130 ns as the fluence increased from 700 to 1750 mJ cm‑2. Nanostructures with a spatial period close to the laser wavelength were formed on both copper thin film and silicon substrate after nanosecond Nd:YAG laser (10 ns, 266 nm, 1 Hz) irradiation. In the picosecond regime, using an Nd:YAG laser (40 ps, 266 nm, 1 Hz), different nanostructures, from spikes to laser-induced periodic surface structures, were formed on 500 nm copper thin film and were analyzed with respect to the drop in dynamic reflectivity changes versus the number of laser shots.

  5. Direct observation of periodic swelling and collapse of polymer chain induced by the Belousov-Zhabotinsky reaction.

    PubMed

    Hara, Yusuke; Mayama, Hiroyuki; Yamaguchi, Yoshinori; Takenaka, Yoshiko; Fukuda, Ryushi

    2013-11-21

    By utilizing a quartz crystal microbalance with dissipation (QCM-D), we directly observed the self-oscillating behavior of a polymer chain induced by the Belousov-Zhabotinsky (BZ) reaction. We succeeded in measuring self-oscillations of the resonance frequency (Δf) and dissipation (ΔD), which originate in the self-oscillating behavior of the polymer chain on a gold surface induced by the BZ reaction. We synthesized a self-oscillating polymer chain with Ru as the catalyst of the BZ reaction and a chemical adsorption site, so as to directly observe its periodic swelling and collapse on the gold surface. Distinct self-oscillation of ΔD synchronized with the self-oscillation Δf was observed. The period of the Δf self-oscillation was about 400 s, and the induction time was about 6.5 h. In QCM-D measurements, we found that the peaks of Δf and ΔD oscillations did not coincide in time because the state of the Gaussian chain did not coincide with the maximum value of Δf. Moreover, examination of the relationship between Δf and ΔD revealed that their oscillatory waveforms were identical in frequency but differed in phase and amplitude.

  6. Hunting for the beat in the body: on period and phase locking in music-induced movement

    PubMed Central

    Burger, Birgitta; Thompson, Marc R.; Luck, Geoff; Saarikallio, Suvi H.; Toiviainen, Petri

    2014-01-01

    Music has the capacity to induce movement in humans. Such responses during music listening are usually spontaneous and range from tapping to full-body dancing. However, it is still unclear how humans embody musical structures to facilitate entrainment. This paper describes two experiments, one dealing with period locking to different metrical levels in full-body movement and its relationships to beat- and rhythm-related musical characteristics, and the other dealing with phase locking in the more constrained condition of sideways swaying motions. Expected in Experiment 1 was that music with clear and strong beat structures would facilitate more period-locked movement. Experiment 2 was assumed to yield a common phase relationship between participants' swaying movements and the musical beat. In both experiments optical motion capture was used to record participants' movements. In Experiment 1 a window-based period-locking probability index related to four metrical levels was established, based on acceleration data in three dimensions. Subsequent correlations between this index and musical characteristics of the stimuli revealed pulse clarity to be related to periodic movement at the tactus level, and low frequency flux to mediolateral and anteroposterior movement at both tactus and bar levels. At faster tempi higher metrical levels became more apparent in participants' movement. Experiment 2 showed that about half of the participants showed a stable phase relationship between movement and beat, with superior-inferior movement most often being synchronized to the tactus level, whereas mediolateral movement was rather synchronized to the bar level. However, the relationship between movement phase and beat locations was not consistent between participants, as the beat locations occurred at different phase angles of their movements. The results imply that entrainment to music is a complex phenomenon, involving the whole body and occurring at different metrical levels

  7. Structural and optical properties of titanium functionalized periodic mesostructured organosilica framework via evaporation-induced self-assembly method.

    PubMed

    Abdul Wahab, M; He, Chaobin

    2013-04-01

    We describe an evaporation-induced self-assembly method for incorporating Ti into framework of ethane-bridged periodic mesoporous organosilica (PMO). The X-ray diffraction (XRD), transmission electron microscopy (TEM), solid-state 29Si and 13C nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared spectroscopy (FT-IR), and UV-vis spectroscopy were used to elucidate the optical and structural properties of Ti-incorporated PMO materials. The degree of mesopore ordering and the structural properties were found to be dependent on the loading of Ti into the framework of PMO materials, as confirmed by XRD, and surface structural properties. UV-vis spectra also support the incorporation of Ti into framework of PMO. TEM analyses suggested the formation of mesopores for the pure PMO and Ti-incorporated PMO samples. The solid-state NMR and FT-IR spectra have confirmed the presence of organic fragment in the final PMO framework.

  8. Laser-Induced Periodic Surface Structures on P3HT and on Its Photovoltaic Blend with PC71BM.

    PubMed

    Cui, Jing; Rodríguez-Rodríguez, Álvaro; Hernández, Margarita; García-Gutiérrez, Mari-Cruz; Nogales, Aurora; Castillejo, Marta; Moseguí González, Daniel; Müller-Buschbaum, Peter; Ezquerra, Tiberio A; Rebollar, Esther

    2016-11-23

    We describe the conditions for optimal formation of laser-induced periodic surface structures (LIPSS) over poly(3-hexylthiophene) (P3HT) spin-coated films. Optimal LIPSS on P3HT are observed within a particular range of thicknesses and laser fluences. These conditions can be translated to the photovoltaic blend formed by the 1:1 mixture of P3HT and [6,6]-phenyl C71-butyric acid methyl ester (PC71BM) when deposited on an indium tin oxide (ITO) electrode coated with (poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS). Solar cells formed by using either a bilayer of P3HT structured by LIPSS covered by PC71BM or a bulk heterojunction with a P3HT:PC71BM blend structured by LIPSS exhibit generation of electrical photocurrent under light illumination. These results suggest that LIPSS could be a compatible technology with organic photovoltaic devices.

  9. Mold-Based Application of Laser-Induced Periodic Surface Structures (LIPSS) on Biomaterials for Nanoscale Patterning.

    PubMed

    Hendrikson, Wim; Masman-Bakker, Wendy; van Bochove, Bas; Skolski, Johann; Eichstädt, Justus; Koopman, Bart; van Blitterswijk, Clemens; Grijpma, Dirk; Römer, Gert-Willem; Moroni, Lorenzo; Rouwkema, Jeroen

    2016-01-01

    Laser-induced periodic surface structures (LIPSS) are highly regular, but at the same time contain a certain level of disorder. The application of LIPSS is a promising method to functionalize biomaterials. However, the absorption of laser energy of most polymer biomaterials is insufficient for the direct application of LIPSS. Here, we report the application of LIPSS to relevant biomaterials using a two-step approach. First, LIPSS are fabricated on a stainless steel surface. Then, the structures are replicated onto biomaterials using the steel as a mold. Results show that LIPSS can be transferred successfully using this approach, and that human mesenchymal stromal cells respond to the transferred structures. With this approach, the range of biomaterials that can be supplied with LIPSS increases dramatically.

  10. Enhancement of surface area and wettability properties of boron doped diamond by femtosecond laser-induced periodic surface structuring

    DOE PAGES

    Granados, Eduardo; Calderon, Miguel Martinez; Krzywinski, Jacek; ...

    2017-08-28

    We demonstrate the formation of laser-induced periodic surface structures (LIPSS) in boron-doped diamond (BDD) by irradiation with femtosecond near-IR laser pulses. The results show that the obtained LIPSS are perpendicular to the laser polarization, and the ripple periodicity is on the order of half of the irradiation wavelength. The surface structures and their electrochemical properties were characterized using Raman micro-spectroscopy, in combination with scanning electron and atomic force microscopies. The textured BDD surface showed a dense and large surface area with no change in its structural characteristics. The effective surface area of the textured BDD electrode was approximately 50% largermore » than that of a planar substrate, while wetting tests showed that the irradiated area becomes highly hydrophilic. Lastly, our results indicate that LIPSS texturing of BDD is a straightforward and simple technique for enhancing the surface area and wettability properties of the BDD electrodes, which could enable higher current efficiency and lower energy consumption in the electrochemical oxidation of toxic organics.« less

  11. Tribological performance of femtosecond laser-induced periodic surface structures on titanium and a high toughness bearing steel

    NASA Astrophysics Data System (ADS)

    Bonse, J.; Koter, R.; Hartelt, M.; Spaltmann, D.; Pentzien, S.; Höhm, S.; Rosenfeld, A.; Krüger, J.

    2015-05-01

    Laser-induced periodic surface structures (LIPSS, ripples) were processed on steel (X30CrMoN15-1) and titanium (Ti) surfaces by irradiation in air with linear polarized femtosecond laser pulses with a pulse duration of 30 fs at 790 nm wavelength. For the processing of large LIPSS covered surface areas (5 mm × 5 mm), the laser fluence and the spatial spot overlap were optimized in a sample-scanning geometry. The laser-processed surfaces were characterized by optical microscopy (OM), white light interference microscopy (WLIM) and scanning electron microscopy (SEM). Spatial LIPSS periods between 450 and 600 nm were determined. The nanostructured surface regions were tribologically tested under reciprocal sliding conditions against a 10-mm diameter ball of hardened 100Cr6 steel. Paraffin oil and engine oil were used as lubricants for 1000 sliding cycles at 1 Hz with a normal load of 1.0 N. The corresponding wear tracks were analyzed by OM and SEM. In particular cases, the laser-generated nanostructures endured the tribological treatment. Simultaneously, a significant reduction of the friction coefficient and the wear was observed in the laser-irradiated (LIPSS-covered) areas when compared to the non-irradiated surface. The experiments reveal the potential benefit of laser surface structuring for tribological applications.

  12. Laser-induced periodic surface structures on zinc oxide crystals upon two-colour femtosecond double-pulse irradiation

    NASA Astrophysics Data System (ADS)

    Höhm, S.; Rosenfeld, A.; Krüger, J.; Bonse, J.

    2017-03-01

    In order to study the temporally distributed energy deposition in the formation of laser-induced periodic surface structures (LIPSS) on single-crystalline zinc oxide (ZnO), two-colour double-fs-pulse experiments were performed. Parallel or cross-polarised double-pulse sequences at 400 and 800 nm wavelength were generated by a Mach–Zehnder interferometer, exhibiting inter-pulse delays up to a few picoseconds between the sub-ablation 50-fs-pulses. Twenty two-colour double-pulse sequences were collinearly focused by a spherical mirror to the sample surface. The resulting LIPSS periods and areas were analysed by scanning electron microscopy. The delay-dependence of these LIPSS characteristics shows a dissimilar behaviour when compared to the semiconductor silicon, the dielectric fused silica, or the metal titanium. A wavelength-dependent plasmonic mechanism is proposed to explain the delay-dependence of the LIPSS on ZnO when considering multi-photon excitation processes. Our results support the involvement of nonlinear processes for temporally overlapping pulses. These experiments extend previous two-colour studies on the indirect semiconductor silicon towards the direct wide band-gap semiconductor ZnO and further manifest the relevance of the ultrafast energy deposition for LIPSS formation.

  13. Randomly-disordered-periodic-induced chaos in a piezoelectric vibration energy harvester system with fractional-order physical properties

    NASA Astrophysics Data System (ADS)

    Liu, Di; Xu, Yong; Li, Junlin

    2017-07-01

    The chaotic behavior of the piezoelectric vibration energy harvester (VEH) system with fractional order physical properties under randomly disordered periodic excitations is investigated. By using random Melnikov method, a mean square criterion is used to detect the necessary conditions for chaotic motion of this stochastic system. The results indicate that the increase of the noise intensity will result in the occurrence of chaos and the changes of the possible chaotic region in phase space, which first enlarging and then shrinking with a change in trend. The threshold of amplitude of randomly disordered periodic for the onset of chaos is determined by the numerical calculation via the largest Lyapunov exponent. The effects of noise intensity on chaos are also investigated through the largest Lyapunov exponent, phase portraits, Poincaré maps. At the same time, the effects of intensity of random frequency on the mean square voltage are further discussed, which show that the square voltage is in positive proportion to the size of the chaotic region. It is demonstrated that the essential changes of the dynamical behavior of the piezoelectric energy harvester system with fractional order physical properties will occur through changing the noise intensity, which can not only induce or suppress the onset of the chaos, but also raise or reduce the mean square voltage. Finally, the 0-1 test of responses is used to quantify the responses of VEH system, which further supports the effects of noise intensity on chaotic behavior of the system.

  14. Cognitive functions after pilocarpine-induced status epilepticus: changes during silent period precede appearance of spontaneous recurrent seizures.

    PubMed

    Hort, J; Broźek, G; Mares, P; Langmeier, M; Komárek, V

    1999-09-01

    To study the possible relation between spontaneous recurrent seizures (SRS) and the derangement of cognitive memory. Status epilepticus (SE) was induced in adult Long-Evans rats by pilocarpine (320 mg/kg, i.p.) and interrupted after 2 h by clonazepam (CZPs mg/kg, i.p.). In addition to the animals that were given pilocarpine and CZP (group P), two groups received ketamine (100 mg/kg, i.p.): the first group 15 minutes after SE onset (group K15), and the second immediately after the CZP (group K120). Control groups were formed from animals not treated with pilocarpine as well as animals that received pilocarpine but did not develop motor seizures. Spatial cognitive memory was tested in the Morris water maze. Testing was impossible for more than 6 days after SE in group P. Ketamine shortened this period for the two groups that received it. During the silent period, deteriorated cognitive memory progressively improved, but the performance of group P started to worsen before the appearance of SRS. Group K120 only expressed a tendency toward declining performance, whereas group K15 never developed SRS, and the behavior of these animals did not differ from that of the controls after the postseizure period was over. Histologically, massive hippocampal cell loss was seen in group P. Ketamine protected hippocampal cells in a time-dependent manner; group K15 did not exhibit any obvious necrosis in the hippocampus. There is no close relation between cognitive functions and the appearance of SRS, because ketamine, administered 120 min after the beginning of SE, prevented the derangment of cognitive functions but not the appearance of SRSs.

  15. Semantic Wavelet-Induced Frequency-Tagging (SWIFT) Periodically Activates Category Selective Areas While Steadily Activating Early Visual Areas

    PubMed Central

    Koenig-Robert, Roger; VanRullen, Rufin; Tsuchiya, Naotsugu

    2015-01-01

    Primate visual systems process natural images in a hierarchical manner: at the early stage, neurons are tuned to local image features, while neurons in high-level areas are tuned to abstract object categories. Standard models of visual processing assume that the transition of tuning from image features to object categories emerges gradually along the visual hierarchy. Direct tests of such models remain difficult due to confounding alteration in low-level image properties when contrasting distinct object categories. When such contrast is performed in a classic functional localizer method, the desired activation in high-level visual areas is typically accompanied with activation in early visual areas. Here we used a novel image-modulation method called SWIFT (semantic wavelet-induced frequency-tagging), a variant of frequency-tagging techniques. Natural images modulated by SWIFT reveal object semantics periodically while keeping low-level properties constant. Using functional magnetic resonance imaging (fMRI), we indeed found that faces and scenes modulated with SWIFT periodically activated the prototypical category-selective areas while they elicited sustained and constant responses in early visual areas. SWIFT and the localizer were selective and specific to a similar extent in activating category-selective areas. Only SWIFT progressively activated the visual pathway from low- to high-level areas, consistent with predictions from standard hierarchical models. We confirmed these results with criterion-free methods, generalizing the validity of our approach and show that it is possible to dissociate neural activation in early and category-selective areas. Our results provide direct evidence for the hierarchical nature of the representation of visual objects along the visual stream and open up future applications of frequency-tagging methods in fMRI. PMID:26691722

  16. Semantic Wavelet-Induced Frequency-Tagging (SWIFT) Periodically Activates Category Selective Areas While Steadily Activating Early Visual Areas.

    PubMed

    Koenig-Robert, Roger; VanRullen, Rufin; Tsuchiya, Naotsugu

    2015-01-01

    Primate visual systems process natural images in a hierarchical manner: at the early stage, neurons are tuned to local image features, while neurons in high-level areas are tuned to abstract object categories. Standard models of visual processing assume that the transition of tuning from image features to object categories emerges gradually along the visual hierarchy. Direct tests of such models remain difficult due to confounding alteration in low-level image properties when contrasting distinct object categories. When such contrast is performed in a classic functional localizer method, the desired activation in high-level visual areas is typically accompanied with activation in early visual areas. Here we used a novel image-modulation method called SWIFT (semantic wavelet-induced frequency-tagging), a variant of frequency-tagging techniques. Natural images modulated by SWIFT reveal object semantics periodically while keeping low-level properties constant. Using functional magnetic resonance imaging (fMRI), we indeed found that faces and scenes modulated with SWIFT periodically activated the prototypical category-selective areas while they elicited sustained and constant responses in early visual areas. SWIFT and the localizer were selective and specific to a similar extent in activating category-selective areas. Only SWIFT progressively activated the visual pathway from low- to high-level areas, consistent with predictions from standard hierarchical models. We confirmed these results with criterion-free methods, generalizing the validity of our approach and show that it is possible to dissociate neural activation in early and category-selective areas. Our results provide direct evidence for the hierarchical nature of the representation of visual objects along the visual stream and open up future applications of frequency-tagging methods in fMRI.

  17. Anti-inflammatory effects of Lactococcus lactis NCDO 2118 during the remission period of chemically induced colitis

    PubMed Central

    2014-01-01

    Background Many probiotic bacteria have been described as promising tools for the treatment and prevention of inflammatory bowel diseases (IBDs). Most of these bacteria are lactic acid bacteria, which are part of the healthy human microbiota. However, little is known about the effects of transient bacteria present in normal diets, including Lactococcus lactis. Methods In the present study, we analysed the immunomodulatory effects of three L. lactis strains in vitro using intestinal epithelial cells. L. lactis NCDO 2118 was administered for 4 days to C57BL/6 mice during the remission period of colitis induced by dextran sodium sulphate (DSS). Results Only one strain, L. lactis NCDO 2118, was able to reduce IL-1β-induced IL-8 secretion in Caco-2 cells, suggesting a potential anti-inflammatory effect. Oral treatment using L. lactis NCDO 2118 resulted in a milder form of recurrent colitis than that observed in control diseased mice. This protective effect was not attributable to changes in secretory IgA (sIgA); however, NCDO 2118 administration was associated with an early increase in IL-6 production and sustained IL-10 production in colonic tissue. Mice fed L. lactis NCDO 2118 had an increased number of regulatory CD4+ T cells (Tregs) bearing surface TGF-β in its latent form (Latency-associated peptide-LAP) in the mesenteric lymph nodes and spleen. Conclusions Here, we identified a new probiotic strain with a potential role in the treatment of IBD, and we elucidated some of the mechanisms underlying its anti-inflammatory effect. PMID:25110521

  18. Sea Level Variability in the Coastal Ocean Induced by Atmospheric Forcing for the Period 1871-2012

    NASA Astrophysics Data System (ADS)

    Jorda, G.; Compo, G. P.; Nerem, R. S.; Lyard, F.

    2015-12-01

    Global mean sea level (GMSL) is the preferred proxy to assess changes in the ocean heat and freshwater content as it is less affected by internal variability that regional sea level (Cazenave and Nerem, 2004). However, what really matters for society is the variability of sea level at regional scales as the impact of sea level variations occur at those scales. Regional sea level (RSL) is not only affected by the same processes that GMSL (thermal expansion/contraction and water addition/removal) but also by the redistribution of mass. In particular, due to atmospheric forcing (i.e. atmospheric sea level pressure and wind stress) is the principal mechanism for the water redistribution in the ocean and accounts for a large fraction of the coastal sea level variance. In particular, it is the dominant mechanism for the variability in the subtidal to intraseasonal range (i.e. from days to months). This includes storm surge events, which are responsible for the largest damages in coastal regions. At frequencies from seasonal to interannual, its relevance is comparable to the steric contribution, specially at high and low latitudes (Fukumori et al. 1998). For the decadal to multidecadal range it is usually assumed that it has a secondary role, but this has not yet been studied in depth. In this presentation we will show the results obtained from a new global simulation of atmospherically induced sea level variability for the period 1871-2012. This simulation uses the NOAA Twentieth Century Reanalysis (Compo et al., 2011) to force a global ocean barotropic model (TUGO, Carrère and Lyard, 2003). We will focus on the description of the impact of mass redistribution on coastal sea level variability at interannual to multidecadal scales and from a global perspective. We will also show how this mass redistribution can induce errors in GMSL trends and accelerations derived from tide gauge reconstructions.

  19. Growth Period Effects on the Protective Properties of Aloe vera Against t-BHP-Induced Oxidative Stress in Chang Cells.

    PubMed

    Hwang, Jin-Woo; Kim, Eun-Kyung; Kim, Yon-Suk; Lee, Jae Woong; Lee, Jeong-Jun; Pyo, Han-Jong; Moon, Sang-Ho; Jeon, Byong-Tae; Park, Pyo-Jam

    2015-12-28

    Aloe vera has been used in traditional medicine for the therapy of a variety of disorders, such as wounds and burns. However, few studies have examined the antioxidant capacities of A. vera plants during different growth periods. In order to investigate the effects of growth on antioxidant activity, A. vera was prepared from 2-, 4-, 6-, 8-, and 12-month-old aloe. The extracts from 6-month-old A. vera showed the highest contents of flavonoids (9.750 mg catechin equivalent/g extract) and polyphenols (23.375 mg gallic acid equivalent/g extract) and the highest ferric reducing antioxidant power (0.047 mM ferrous sulfate equivalent/mg extract). The extract from 6-month-old A. vera exhibited the highest free radical scavenging potential, and the lowest IC50 values were found for 2,2-diphenyl-1-picrylhydrazyl (0.26 mg/ml) and alkyl radicals (0.50 mg/ml). In addition, the extract from 6-month-old A. vera showed the greatest effects on cell viability in normal liver cells. Based on these findings, the extract from 6-month-old A. vera was examined further in order to determine its protective potential against tert-butyl hydroperoxide (t-BHP)-induced oxidative stress. The extract from 6-monthold A. vera at a concentration of 0.25 mg/ml showed the highest protective activity against t-BHP-induced reactive oxygen species production. These findings suggested that harvesting regimens were critical in the regulation of effects of the bioactive potential of A. vera on antioxidant activity.

  20. A single daily meal at the beginning of the active or inactive period inhibits food deprivation-induced fatty liver in mice.

    PubMed

    Aoki, Natsumi; Yoshida, Daisuke; Ishikawa, Ryosuke; Ando, Midori; Nakamura, Kaai; Tahara, Yu; Shibata, Shigenobu

    2014-07-01

    Food deprivation (FD) induces hepatic steatosis in both rodents and humans. Although body composition, age, and sex influence hepatic triglyceride (TG) levels after FD, whether feeding patterns affect FD-induced liver TG increases is unknown. We hypothesized that restricted feeding (RF) of 1 meal per day during the active or inactive period (especially the inactive period) augments FD-induced elevation of liver TGs because RF in the inactive period impairs the circadian rhythm. Triglyceride levels and the expression of genes related to TG metabolism in the liver were examined by a bioassay and real-time reverse transcription-polymerase chain reaction, respectively. In the first experiment, when compared to nonfasted mice, mice that fasted for 24 hours showed a 1.5-fold (FD starting during the inactive period) to 3-fold (FD started during the active period) increase in liver TG levels. This experiment showed that TG levels depend upon the starting time of FD. In the second experiment, mice were given free access to food for 3 hours at the beginning of either the inactive ("supper-only") or the active ("breakfast-only") period for 2 weeks. Restricted feeding inhibited the FD-induced increases in liver and serum TG levels, serum free fatty acids, and the expression of genes related to fatty acid uptake in the liver, including fatty acid transport protein 1 (Fatp1) and 4 (Fatp4). Unexpectedly, compared to free feeding, RF during the active or inactive period resulted in resistance to FD-induced fatty liver. This is the first study to demonstrate that feeding patterns affect FD-induced TG accumulation in the mouse liver. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Light-induced phase-shifts in the circadian expression rhythm of mammalian period genes in the mouse heart.

    PubMed

    Sakamoto, K; Ishida, N

    2000-11-01

    To investigate the molecular mechanism that regulates circadian rhythms in mammalian peripheral tissues, we examined the phase shifts evoked by light exposure in the circadian mRNA expression rhythms of mammalian Period genes (mPer1, mPer2 and mPer3) and a clock-controlled gene Dbp, in the mouse heart, by Northern blot analysis. The light pulse did not induce any acute mRNA expression of mPer in the heart, but the pulse gave rise to phase shifts in the circadian mRNA rhythms. On the first day after the exposure, only mPer1 mRNA showed a phase shift, whereas obvious phase shifts were not observed in the rhythms of mPer2, mPer3 and Dbp mRNAs. On the second day, phase shifts occurred to a similar extent in the mRNA rhythms of all four genes examined. The rhythm of mPer1 mRNA shifted fastest among those of the three mPers. Therefore mPer1 seems to play an important role in phase resetting of mammalian peripheral oscillators. Immediate responses to light pulses in mRNA expression of mPers may not be required for phase shifting of peripheral circadian oscillators. Our findings suggest that mammals require more than one day to have peripheral oscillators entrained to a new daily schedule.

  2. Widely tunable LP11 cladding-mode resonance in a twisted mechanically induced long-period fiber grating.

    PubMed

    Nair, Anitha S; Sudeep Kumar, V P; Joe, Hubert

    2015-03-10

    A record tunability of 35 nm for the LP(11) cladding-mode resonance in a twisted mechanically induced long-period fiber grating using standard single-mode communication fiber is demonstrated. By forming the LP(11) resonance far away from its cut-off wavelength and modifying the grooves of the grating in the form of smooth semicircular humps, a high twist sensitivity of 8.75 nm/(rad/cm) and a controlled tunability of 35 nm is achieved. The fiber with its lacquer coating is not broken even at a severe twist rate of 5.44 rad/cm. The present design can be used as a novel variable optical selective wavelength attenuator since the bandwidth, rejection efficiency, and center wavelength can be controlled by changing the grating length, pressure over the grating, and fiber twist, respectively. Using the results, a cost-effective tunable variable optical attenuator for selective channel-blanking applications is also demonstrated. A fine tunability of 1.5 nm is achieved for a twist rate change of 0.1 rad/cm.

  3. Periodic driving control of Raman-induced spin-orbit coupling in Bose-Einstein condensates: The heating mechanisms

    NASA Astrophysics Data System (ADS)

    Gomez Llorente, J. M.; Plata, J.

    2016-06-01

    We focus on a technique recently implemented for controlling the magnitude of synthetic spin-orbit coupling (SOC) in ultracold atoms in the Raman-coupling scenario. This technique uses a periodic modulation of the Raman-coupling amplitude to tune the SOC. Specifically, it has been shown that the effect of a high-frequency sinusoidal modulation of the Raman-laser intensity can be incorporated into the undriven Hamiltonian via effective parameters, whose adiabatic variation can therefore be used to tune the SOC. Here, we characterize the heating mechanisms that can be relevant to this method. We identify the main mechanism responsible for the heating observed in the experiments as basically rooted in driving-induced transfer of population to excited states. Characteristics of that process determined by the harmonic trapping, the decay of the excited states, and the technique used for preparing the system are discussed. Additional heating, rooted in departures from adiabaticity in the variation of the effective parameters, is also described. Our analytical study provides some clues that may be useful in the design of strategies for curbing the effects of heating on the efficiency of the control methods.

  4. Periodic Evolution of a Xe I Population in an Oscillatory Discharge Captured Through Time-Synchronized Laser Induced Fluorescence Techniques

    NASA Astrophysics Data System (ADS)

    Lucca Fabris, Andrea; Young, Christopher; Cappelli, Mark

    2014-10-01

    We track the evolution of the Xe I 6 s '[ 1 / 2 ] 1 - 6 p '[ 3 / 2 ] 2 (834.68 nm air) transition lineshape in a plasma discharge oscillating at 60 Hz. Two time-synchronized laser induced fluorescence techniques based on phase sensitive detection of the fluorescence signal are demonstrated, yielding consistent results. One approach used previously involves a sample-and-hold procedure that collects fluorescence signal at a particular phase in the oscillation period and holds the average value until the following sample. The second method is based on fast switching of the fluorescence signal; only the signal collected inside the acquisition gate is sent to a lock-in amplifier for processing. Both methods rely on modulating the exciting laser beam and the latter permits operation at a much higher frequency range with reduced spectral noise density. The maximum observed peak fluorescence intensity occurs at low discharge currents, although the peak intensity drops to zero at zero discharge current. The peak intensity also decreases at the discharge current maximum. Time-varying properties of the xenon neutrals are extracted from a lineshape analysis. This work is sponsored by the U.S. Air Force Office of Scientific Research with Dr. Mitat Birkan as program manager. CVY acknowledges support from the DOE NNSA Stewardship Science Graduate Fellowship under Contract DE-FC52-08NA28752.

  5. Periodic 18.6-year and cyclic 11-year induced drought and flood in northeastern China and some global implications

    NASA Astrophysics Data System (ADS)

    Currie, Robert Guinn; Fairbridge, Rhodes W.

    The general patterns of climatic evolution in China during the Holocene are reviewed, and following the postglacial eustatic rise of sea-level and the institution of the East Asian Monsoon, the systems and principal fluctuations are found to be concordant with those operating elsewhere in the globe. China's unique wealth of written history provides an abundance of proxy data on the climatic record and that record now furnishes a basis for analysing both long-term and short-term fluctuations, as well as sunspot behavior, that together provide an insight into extraterrestrial forcing. Recent Chinese work suggests a solar forcing, but our own studies suggest rather that a lunar tidal component, reinforced at times by the solar element may prove more important. Analysis of a drought-flood index for Peking (Beijing) in northeastern China since A.D. 1470 supports evidence (Hameed et al., 1983) for both periodic lunar nodal 18.6-year and solar cyclic 11-year induced drought-flood in the region. The nodal term exhibits bistable phasing with respect to epochs of tidal maxima (for our century epochs occurred at 1917.5, 1936.1, 1954.7 and 1973.3), a phenomenon previously found in drought-flood proxy data for South America (Currie, 1983), India (Currie, 1984a), North America (Currie, 1984d), and Africa (Hameed and Currie, 1985; Currie and Hameed, 1985). Solar cycle epochs of drought-flood are tabulated for the past two centuries, and compared with those from North America and Africa.

  6. Sea level variability in the coastal ocean induced by atmospheric forcing for the period 1871-2012

    NASA Astrophysics Data System (ADS)

    Jorda, G.; Compo, G. P.; Nerem, R. S.; Lyard, F.

    2016-02-01

    Global mean sea level (GMSL) is the preferred proxy to assess changes in the ocean heat and freshwater content as it is less affected by internal variability that regional sea level (Cazenave and Nerem, 2004). However, what really matters for society is the variability of sea level at regional scales as the impact of sea level variations occur at those scales. Regional sea level (RSL) is not only affected by the same processes that GMSL (thermal expansion/contraction and water addition/removal) but also by the redistribution of mass. In particular, due to atmospheric forcing (i.e. atmospheric sea level pressure and wind stress) is the principal mechanism for the water redistribution in the ocean and accounts for a large fraction of the coastal sea level variance. In particular, it is the dominant mechanism for the variability in the subtidal to intraseasonal range (i.e. from days to months). This includes storm surge events, which are responsible for the largest damages in coastal regions. At frequencies from seasonal to interannual, its relevance is comparable to the steric contribution, specially at high and low latitudes (Fukumori et al. 1998). For the decadal to multidecadal range it is usually assumed that it has a secondary role, but this has not yet been studied in depth. In this presentation we will show the results obtained from a new global simulation of atmospherically induced sea level variability for the period 1871-2012. This simulation uses the NOAA Twentieth Century Reanalysis (Compo et al., 2011) to force a global ocean barotropic model (TUGO, Carrère and Lyard, 2003). We will focus on the description of the impact of mass redistribution on coastal sea level variability with special focus on the storm surge events and the decadal variations in the intensity of the surges.

  7. Monozygotic twin model reveals novel embryo-induced transcriptome changes of bovine endometrium in the preattachment period.

    PubMed

    Klein, Claudia; Bauersachs, Stefan; Ulbrich, Susanne E; Einspanier, Ralf; Meyer, Heinrich H D; Schmidt, Susanne E M; Reichenbach, Horst-Dieter; Vermehren, Margarete; Sinowatz, Fred; Blum, Helmut; Wolf, Eckhard

    2006-02-01

    Initiation and maintenance of pregnancy are critically dependent on an intact embryo-maternal communication in the preimplantation period. To get new insights into molecular mechanisms underlying this complex dialog, a holistic transcriptome study of endometrium samples from Day 18 pregnant vs. nonpregnant twin cows was performed. This genetically defined model system facilitated the identification of specific conceptus-induced changes of the endometrium transcriptome. Using a combination of subtracted cDNA libraries and cDNA array hybridization, 87 different genes were identified as upregulated in pregnant animals. Almost one half of these genes are known to be stimulated by type I interferons. For the ISG15ylation system, which is assumed to play an important role in interferon tau (IFNT) signaling, mRNAs of four potential components (IFITM1, IFITM3, HSXIAPAF1, and DTX3L) were found at increased levels in addition to ISG15 and UBE1L. These results were further substantiated by colocalization of these mRNAs in the endometrium of pregnant animals shown by in situ hybridization. A functional classification of the identified genes revealed several different biological processes involved in the preparation of the endometrium for the attachment and implantation of the embryo. Specifically, elevated transcript levels were found for genes involved in modulation of the maternal immune system, genes relevant for cell adhesion, and for remodeling of the endometrium. This first systematic study of maternal transcriptome changes in response to the presence of an embryo on Day 18 of pregnancy in cattle is an important step toward deciphering the embryo-maternal dialog using a systems biology approach.

  8. A Brief Period of Hypothermia Induced by Total Liquid Ventilation Decreases End-Organ Damage and Multiorgan Failure Induced by Aortic Cross-Clamping.

    PubMed

    Mongardon, Nicolas; Kohlhauer, Matthias; Lidouren, Fanny; Hauet, Thierry; Giraud, Sébastien; Hutin, Alice; Costes, Bruno; Barau, Caroline; Bruneval, Patrick; Micheau, Philippe; Cariou, Alain; Dhonneur, Gilles; Berdeaux, Alain; Ghaleh, Bijan; Tissier, Renaud

    2016-09-01

    In animal models, whole-body cooling reduces end-organ injury after cardiac arrest and other hypoperfusion states. The benefits of cooling in humans, however, are uncertain, possibly because detrimental effects of prolonged cooling may offset any potential benefit. Total liquid ventilation (TLV) provides both ultrafast cooling and rewarming. In previous reports, ultrafast cooling with TLV potently reduced neurological injury after experimental cardiac arrest in animals. We hypothesized that a brief period of rapid cooling and rewarming via TLV could also mitigate multiorgan failure (MOF) after ischemia-reperfusion induced by aortic cross-clamping. Anesthetized rabbits were submitted to 30 minutes of supraceliac aortic cross-clamping followed by 300 minutes of reperfusion. They were allocated either to a normothermic procedure with conventional ventilation (control group) or to hypothermic TLV (33°C) before, during, and after cross-clamping (pre-clamp, per-clamp, and post-clamp groups, respectively). In all TLV groups, hypothermia was maintained for 75 minutes and switched to a rewarming mode before resumption to conventional mechanical ventilation. End points included cardiovascular, renal, liver, and inflammatory parameters measured 300 minutes after reperfusion. In the normothermic (control) group, ischemia-reperfusion injury produced evidence of MOF including severe vasoplegia, low cardiac output, acute kidney injury, and liver failure. In the TLV group, we observed gradual improvements in cardiac output in post-clamp, per-clamp, and pre-clamp groups versus control (53 ± 8, 64 ± 12, and 90 ± 24 vs 36 ± 23 mL/min/kg after 300 minutes of reperfusion, respectively). Liver biomarker levels were also lower in pre-clamp and per-clamp groups versus control. However, acute kidney injury was prevented in pre-clamp, and to a limited extent in per-clamp groups, but not in the post-clamp group. For instance, creatinine clearance was 4.8 ± 3.1 and 0.5 ± 0.6 m

  9. Enhanced tropical storm activity during the African Humid Period induced by Sahara greening and reduced dust emissions

    NASA Astrophysics Data System (ADS)

    Pausata, F. S. R.; Emanuel, K.; Zhang, Q.; Chiacchio, M.; Diro, G. T.; Sushama, L.; Stager, J. C.; Donnelly, J. P.

    2016-12-01

    Given the devastating socioeconomics impact of tropical cyclones (TCs), understanding the amplitude of natural variability is of paramount importance for society. Historical records of TCs are too short to be able to capture such changes and TC paleo-sedimentary archives, spanning several millennia are still very few and patchy. Here we use a fully coupled ocean-atmosphere model to simulate the climate during the African Humid Period (AHP, 10,000 - 5,000 years BP) and investigate potential changes in TC activities compared to pre-industrial (PI) climate. We prescribe the mid-Holocene (MH, 6,000 years BP) orbital forcing as well as more extensive vegetation and reduced airborne dust concentrations relative to PI due to wetter climatic condition in the Sahara. Using a downscaling technique for simulating large numbers of TCs, we analyze a set of sensitivity experiments in which prescribed vegetation and dust concentrations are changed in turn. The changes in solar insolation during the MH (MHPMIP simulation) lead to a westward shift in the Western Pacific tropical storm activity, with an increase in TCs in the South China Sea (Fig. 1a). In the MHPMIP simulation, the TC activity is also increased in the Southern Hemisphere. While stronger boreal summer insolation during the MH does not lead to sizeable changes in the tropical Atlantic cyclones, the Sahara greening and especially the reduced dust largely enhance the storm activity in that region (Fig. 1c), in particular in the Caribbean Sea. The greening of the Sahara and reduced dust alter the thermodynamic state, leading to more favorable conditions for tropical storm development. In particular, the strengthening of the West African Monsoon induced by the Sahara greening triggers a change in the atmospheric circulation that embraces the entire boreal tropical regions with a net reduction in wind shear during summer. The dust reduction further increases the warming of the ocean surface up to over a 1°C in the North

  10. Biogeochemistry of Ni and Pb in a periodically flooded arable soil: Fractionation and redox-induced (im)mobilization.

    PubMed

    Antić-Mladenović, Svetlana; Frohne, Tina; Kresović, Mirjana; Stärk, Hans-Joachim; Tomić, Zorica; Ličina, Vlado; Rinklebe, Jörg

    2017-01-15

    The redox-induced (im)mobilization of nickel (Ni) and lead (Pb) under pre-definite redox conditions and their binding forms were studied in a periodically flooded, slightly acidic arable soil enriched with serpentine minerals at the Velika Morava River valley, Serbia. The total contents of Ni and Pb were 152 and 109 mg kg(-1), respectively. Geochemical fractionation of Ni, combined with mineralogical analysis, confirmed its geogenic origin in the soil. Potentially mobile fractions were the dominating binding forms of Pb; thus, indicating anthropogenic sources as prevailing. Risk assessment indicated a low risk of Ni and Pb transfer from soil to other environmental constituents. However, the results imply that geogenic metals might pose higher environmental risk than those from anthropogenic origin, in dependence of their total concentrations and contents in the specific solid-phase fractions. Flooding of the soil was simulated in an automated biogeochemical microcosm system, which allows a control and a continuous measurements of redox potential (EH) and pH. Subsequently, the EH was increased in steps of approximately 100 mV from anoxic to oxic conditions. Concurrently, the concentrations of soluble Ni, Pb, iron (Fe), manganese (Mn), dissolved organic carbon (DOC), and sulfates were measured. The EH was brought from low to high values (-220 to 520 mV) and correlated negative with soluble Ni, Pb, Fe, Mn and DOC. Soluble Ni ranged from 125 to 228 μg l(-1) while Pb ranged from 3.0 to 21.4 μg l(-1). Concentrations of both metals in solution were high at low EH and decreased with increasing EH. Nickel immobilization may be attributed to sorption to or co-precipitation with re-oxidized Fe-Mn (hydr)oxides, whereas Pb, in addition, might be immobilized via precipitation with inorganic ligands, such as carbonates and phosphates. The results imply that Ni and Pb solubility might also be related to the formation of metal-DOC complexes. The detected dynamic and

  11. Painful periods (dysmenorrhea) (image)

    MedlinePlus

    ... caused by hormone-induced uterine contractions before the period. Secondary dysmenorrhea may be caused by abnormal conditions ... serious conditions is present, the treatment for painful periods is pain relief. If a hormone imbalance is ...

  12. Femtosecond-laser-induced periodic surface structures on magnetic layer targets: The roles of femtosecond-laser interaction and of magnetization

    NASA Astrophysics Data System (ADS)

    Czajkowski, Klaus; Ratzke, Markus; Varlamova, Olga; Reif, Juergen

    2017-09-01

    We investigate femtosecond laser induced periodic surface structures (LIPSS) on a complex multilayer target, namely a 20-GB computer hard disk (HD), consisting of a metallic substrate, a magnetic layer, and a thin polymeric protective layer. Depending on the dose (fluence × number of pulses) first the polymeric cover layer is completely removed, revealing a periodic surface modulation of the magnetic layer which seems not to be induced by the laser action. At higher dose, the magnetic layer morphology is strongly modified by laser-induced periodic structures (LIPS) and, finally, kind of an etch stop is reached at the bottom of the magnetic layer. The LIPS shows very high modulation depth below and above the original surface level. In the present work, the role of magnetization and magneto-mechanic forces in the structure formation process is studied by monitoring the bit-wise magnetization of the HD with a magnetic force microscope. It is shown that the structures at low laser dose are reflecting the magnetic bits. At higher dose the magnetic influence appears to be extinguished on the account of LIPS. This suggests a transient overcoming the Curie temperature and an associated loss of magnetic order. The results compare well with our model of LIPS/LIPSS formation by self-organized relaxation from a laser-induced thermodynamic instability.

  13. Mastication-induced modulation of the jaw-opening reflex during different periods of mastication in awake rabbits.

    PubMed

    Mostafeezur, Rahman; Yamamura, Kensuke; Kurose, Masayuki; Yamada, Yoshiaki

    2009-02-13

    The present study aimed to determine if sensory inputs from the intraoral mechanoreceptors similarly contributed to regulating the activity of the jaw-opening muscles throughout the masticatory sequence. We also aimed to determine if sensory inputs from the chewing and non-chewing sides equally regulated the activity of the jaw-opening muscles. Electromyographic (EMG) activities of jaw muscles (digastric and masseter) and jaw movements were recorded in awake rabbits. The entire masticatory sequence was divided into preparatory, rhythmic-chewing and preswallow periods, based on jaw muscles activity and jaw movements. The jaw-opening reflex (JOR) was evoked by unilateral low-intensity stimulation of the inferior alveolar nerve (IAN) on either the chewing or non-chewing side. Amplitude of the JOR was assessed by measuring peak-to-peak EMG activity in the digastric muscle, and was compared among the masticatory periods and between the chewing and non-chewing sides. The JOR was strongly suppressed during the jaw-closing phase in the rhythmic-chewing and preswallow periods, but this effect was transiently attenuated during the late part of the jaw-opening phase in these periods. However, modulation of the JOR varied from strong suppression to weak facilitation during the preparatory period. The patterns of JOR modulation were similar on the chewing and non-chewing sides in all masticatory periods. The results suggest that the sensory inputs from the intraoral mechanoreceptors regulate the activity of the jaw-opening muscles differently during the preparatory period compared with the other masticatory periods. Sensory inputs from both the chewing and non-chewing sides similarly regulate the activity of the jaw-opening muscles.

  14. Complex periodic micro/nanostructures on 6H-SiC crystal induced by the interference of three femtosecond laser beams.

    PubMed

    Jia, X; Jia, T Q; Ding, L E; Xiong, P X; Deng, L; Sun, Z R; Wang, Z G; Qiu, J R; Xu, Z Z

    2009-03-15

    We reported three types of complex micro/nanostructures on 6H-SiC crystal induced by the interferences of three femtosecond laser beams by arranging three types of laser polarization combinations. The micro/nanostructures are composed of two parts: two-dimensional long-periodic micropatterns determined by the interferential intensity pattern and short-periodic nanopatterns determined by the interferential polarization pattern. Theoretical calculation indicates that the different polarization combinations will lead to a distinct complex interferential polarization pattern and intensity pattern, and they accord well with the experimental results.

  15. Periodic disruptions induced by high repetition rate femtosecond pulses on magnesium-oxide-doped lithium niobate surfaces

    NASA Astrophysics Data System (ADS)

    Zhang, Shuanggen; Kan, Hongli; Zhai, Kaili; Ma, Xiurong; Luo, Yiming; Hu, Minglie; Wang, Qingyue

    2017-02-01

    In this paper, we demonstrate the periodic disruption formation on magnesium-oxide-doped lithium niobate surfaces by a femtosecond fiber laser system with wavelength and repetition rate of 1040 nm and 52 MHz, respectively. Three main experimental conditions, laser average power, scanning speed, and orientation of sample were systematically studied. In particular, the ablation morphologies of periodic disruptions under different crystal orientations were specifically researched. The result shows that such disruptions consisting of a bamboo-like inner structure appears periodically for focusing on the surface of X-, Y- and Z-cut wafers, which are formed by a rapid quenching of the material. Meanwhile, due to the anisotropic property, the bamboo-like inner structures consist of a cavity only arise from X- and Z-cut orientation.

  16. Periodic porous stripe patterning in a polymer blend film induced by phase separation during spin-casting.

    PubMed

    Kim, Jae-Kyung; Taki, Kentaro; Nagamine, Shinsuke; Ohshima, Masahiro

    2008-08-19

    A periodic striping pattern with microscale pore size is observed on the surface of thin films prepared by spin-casting from a polystyrene (PS) and polyethylene glycol (PEG) blend solution. The pattern is created by the convection generated by thermal gradients in the solution between the substrate and film solution during solvent evaporation, the radial flow of the spin-coated solution, and the primary and secondary phase separation of the PS and PEG solutions. The formation mechanism of the periodic porous stripe pattern is discussed, wherein the effects of the polymer blend weight ratio, polymer concentration, and drying rate on the formation of the periodic porous striping pattern are investigated using scanning electron and atomic force microscopy.

  17. Euclidian embeddings of periodic nets: definition of a topologically induced complete set of geometric descriptors for crystal structures.

    PubMed

    Eon, Jean-Guillaume

    2011-01-01

    Crystal-structure topologies, represented by periodic nets, are described by labelled quotient graphs (or voltage graphs). Because the edge space of a finite graph is the direct sum of its cycle and co-cycle spaces, a Euclidian representation of the derived periodic net is provided by mapping a basis of the cycle and co-cycle spaces to a set of real vectors. The mapping is consistent if every cycle of the basis is mapped on its own net voltage. The sum of all outgoing edges at every vertex may be chosen as a generating set of the co-cycle space. The embedding maps the cycle space onto the lattice L. By analogy, the concept of the co-lattice L* is defined as the image of the generators of the co-cycle space; a co-lattice vector is proportional to the distance vector between an atom and the centre of gravity of its neighbours. The pair (L, L*) forms a complete geometric descriptor of the embedding, generalizing the concept of barycentric embedding. An algebraic expression permits the direct calculation of fractional coordinates. Non-zero co-lattice vectors allow nets with collisions, displacive transitions etc. to be dealt with. The method applies to nets of any periodicity and dimension, be they crystallographic nets or not. Examples are analyzed: α-cristobalite, the seven unstable 3-periodic minimal nets etc.

  18. Study of the formation of thermochemical laser-induced periodic surface structures on Cr, Ti, Ni and NiCr films under femtosecond irradiation

    NASA Astrophysics Data System (ADS)

    Dostovalov, A. V.; Korolkov, V. P.; Terentyev, V. S.; Okotrub, K. A.; Dultsev, F. N.; Babin, S. A.

    2017-07-01

    The formation of femtosecond laser-induced periodic surface structures (LIPSS's) on Cr, Ti, Ni and NiCr films (with different Cr contents) is investigated. It is established that thermochemical LIPSS's with periods of 950, 930 and 980 nm are formed, respectively, on the surfaces of titanium, chromium, and nichrome (with a chromium content of 20%); however, thermochemical LIPSS's are not formed on the surfaces of nickel and nichrome with a low chromium content, although Raman data indicate that oxidation occurs in all cases. A weakly ordered ablated structure with a period of 250-300 nm is found to be formed on oxidised areas of thermochemical LIPSS's in the case of chromium and nichrome (80/20). Experimental data on selective etching of thermochemical LIPSS's on titanium and chromium films are presented.

  19. Formation of 100-nm periodic structures on a titanium surface by exploiting the oxidation and third harmonic generation induced by femtosecond laser pulses.

    PubMed

    Li, Xian-Feng; Zhang, Cheng-Yun; Li, Hui; Dai, Qiao-Feng; Lan, Sheng; Tie, Shao-Long

    2014-11-17

    Periodic surface structures with periods as small as about one-tenth of the irradiating femtosecond (fs) laser light wavelength were created on the surface of a titanium (Ti) foil by exploiting laser-induced oxidation and third harmonic generation (THG). They were achieved by using 100-fs laser pulses with a repetition rate of 1 kHz and a wavelength ranging from 1.4 to 2.2 μm. It was revealed that an extremely thin TixOy layer was formed on the surface of the Ti foil after irradiating fs laser light with a fluence smaller than the ablation threshold of Ti, leading to a significant enhancement in THG which may exceed the ablation threshold of TixOy. As compared with Ti, the maximum efficacy factor for TixOy appears at a larger normalized wavevector in the direction perpendicular to the polarization of the fs laser light. As a result, the THG-dominated laser ablation of TixOy induces 100-nm periodic structures parallel to the polarization of the fs laser light. The depth of the periodic structures was found to be ~10 nm by atomic force microscopy and the formation of the thin TixOy layer was verified by energy dispersive X-ray spectroscopy.

  20. High speed inscription of uniform, large-area laser-induced periodic surface structures in Cr films using a high repetition rate fs laser.

    PubMed

    Ruiz de la Cruz, A; Lahoz, R; Siegel, J; de la Fuente, G F; Solis, J

    2014-04-15

    We report on the fabrication of laser-induced periodic surface structures in Cr films upon high repetition rate fs laser irradiation (up to 1 MHz, 500 fs, 1030 nm), employing beam scanning. Highly regular large-area (9  cm2) gratings with a relative diffraction efficiency of 42% can be produced within less than 6 min. The ripple period at moderate and high fluences is 0.9 μm, with a small period of 0.5 μm appearing at lower energies. The role of the irradiation parameters on the characteristics of the laser-induced periodic surface structures (LIPSS) is studied and discussed in the frame of the models presently used. We have identified the polarization vector orientation with respect to the scan direction as a key parameter for the fabrication of high-quality, large-area LIPSS, which, for perpendicular orientation, allows the coherent extension of the sub-wavelength structure over macroscopic distances. The processing strategy is robust in terms of broad parameter windows and applicable to other materials featuring LIPSS.

  1. Periodate-treated, non-anticoagulant heparin-carrying polystyrene (NAC-HCPS) affects angiogenesis and inhibits subcutaneous induced tumour growth and metastasis to the lung

    PubMed Central

    Ono, K; Ishihara, M; Ishikawa, K; Ozeki, Y; Deguchi, H; Sato, M; Hashimoto, H; Saito, Y; Yura, H; Kurita, A; Maehara, T

    2002-01-01

    Periodate-treated, non-anticoagulant heparin-carrying polystyrene consists of about ten periodate-oxidized, alkaline-degraded low molecular weight-heparin chains linked to a polystyrene core and has a markedly lower anti-coagulant activity than heparin. In this study, we evaluated the effect of non-anticoagulant heparin-carrying polystyrene on tumour growth and metastasis. Non-anticoagulant heparin-carrying polystyrene has a higher activity to inhibit vascular endothelial growth factor-165-, fibroblast growth factor-2- or hepatocyte growth factor-induced human microvascular endothelial cell growth than heparin, ten periodate-oxidized-heparin and ten periodate-oxidized-low molecular weight-heparin, which is probably due to the heparin-clustering effect of non-anticoagulant heparin-carrying polystyrene. Non-anticoagulant heparin-carrying polystyrene inhibited human microvascular endothelial cell, B16 melanoma and Lewis lung cancer cell adhesion to Matrigel-coated plates. Non-anticoagulant heparin-carrying polystyrene also showed strong inhibitory activities in the tubular formation of endothelial cells on Matrigel and B16-melanoma and Lewis lung cancer cell invasion in a Matrigel-coated chamber assay. In vivo studies showed that growth of subcutaneous induced tumours and lung metastasis of B16-melanoma and Lewis lung cancer cells were more effectively inhibited by non-anticoagulant heparin-carrying polystyrene than ten periodate-oxidized-heparin and ten periodate-oxidized-low molecular weight-heparin. Furthermore, non-anticoagulant heparin-carrying polystyrene markedly reduced the number of CD34-positive vessels in subcutaneous Lewis lung cancer tumours, indicating a strong inhibition of angiogenesis. These results suggest that non-anticoagulant heparin-carrying polystyrene has an inhibitory activity on angiogenesis and tumour invasion and may be very useful in cancer therapy. British Journal of Cancer (2002) 86, 1803–1812. doi:10.1038/sj.bjc.6600307 www

  2. Universal mechanism for breaking the hc/2e periodicity of flux-induced oscillations in small superconducting rings.

    PubMed

    Vakaryuk, Victor

    2008-10-17

    A universal mechanism of restoration of minimal hc/e periodicity in the response of small superconducting rings or cylinders to the magnetic flux is proposed. The mechanism is based on the dependence of the Cooper pair's internal energy on its motion as a whole and does not rely on the presence of quasiparticles in the system. The thermal equilibrium hc/2e periodicity is broken by an offset of the transition between different current-carrying states. The magnitude of the offset is calculated for an s-wave superconducting cylinder of radius R in the limit R>xi_{0}, where xi_{0} is the BCS coherence length and turns out to be exponentially small. A possible enhancement of the effect for nodal superconductors is suggested. Similar conclusions should also apply to the response of charged or neutral superfluids to rotation.

  3. Inkjet printed periodical micropatterns made of inert alumina ceramics induce contact guidance and stimulate osteogenic differentiation of mesenchymal stromal cells.

    PubMed

    Lauria, Ines; Kramer, Michael; Schröder, Teresa; Kant, Sebastian; Hausmann, Anne; Böke, Frederik; Leube, Rudolf; Telle, Rainer; Fischer, Horst

    2016-10-15

    Bioinert high performance ceramics exhibit detrimental features for implant components with direct bone contact because of their low osseointegrating capability. We hypothesized that periodical microstructures made of inert alumina ceramics can influence the osteogenic differentiation of human mesenchymal stromal cells (hMSC). In this study, we manufactured pillared arrays made of alumina ceramics with periodicities as low as 100μm and pillar heights of 40μm employing direct inkjet printing (DIP) technique. The response of hMSC to the microstructured surfaces was monitored by measuring cell morphology, viability and formation of focal adhesion complexes. Osteogenic differentiation of hMSCs was investigated by alkaline phosphatase activity, mineralization assays and expression analysis of respective markers. We demonstrated that MSCs react to the pillars with contact guidance. Subsequently, cells grow onto and form connections between the microstructures, and at the same time are directly attached to the pillars as shown by focal adhesion stainings. Cells build up tissue-like constructs with heights up to the micropillars resulting in increased cell viability and osteogenic differentiating properties. We conclude that periodical micropatterns on the micrometer scale made of inert alumina ceramics can mediate focal adhesion dependent cell adhesion and stimulate osteogenic differentiation of hMSCs. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  4. Watching the wind: seismic data contamination at long-periods due to atmospheric pressure-field-induced tilting

    NASA Astrophysics Data System (ADS)

    de Angelis, S.; Bodin, P.; Hagel, K.; Fletcher, D.

    2010-12-01

    Long-period noise generated by the elastic response of the Earth to atmospheric pressure fluctuations has long been recognized as a limiting factor for seismic investigations. The quality of seismic data recorded by sensitive, near-surface broadband seismometers can be severely corrupted by this effect. During the recent installation of a new broadband site on the Olympic Peninsula in Washington, the Pacific Northwest Seismic Network recorded and investigated elevated daytime noise levels at periods exceeding 30 seconds. Substantial power spectral density variations of the background noise field, 15-20 dB, were observed in the horizontal component seismograms. The pattern of the long-period noise exhibited striking correlations with local fluctuations of the air temperature and wind speed as measured nearby the seismic station by the National Weather Service Forecast Office, Seattle, Washington, and the National Oceanic and Atmospheric Administration. Several past studies have demonstrated that local wind systems may lead to variations of the atmospheric pressure field that deform the ground and perturb seismograms. The rotational component of this motion is detected by horizontal-component seismometers because at periods longer than the sensor’s low corner frequency the sensor is acting essentially as a tiltmeter. We obtained a transfer function that describes the response of the broadband seismometer to a tilt step change and estimated the amplitude of tilt noise to be on the order of 10-9 - 10-8 radians. Within the seismic pass-band of the sensor, it is not possible to remove the tilt signal from the observed seismograms because the details of the tilting depend on the pressure field variations, the compliance of the near surface to pressure variations, and the design and construction of the seismometer vault itself. At longer periods, using the seismic data to recover tilts of tectonic origin is made challenging because of the needed instrument correction

  5. Cardiac induced localised motion of the human torso detected by a long period grating fibre optic sensing scheme

    NASA Astrophysics Data System (ADS)

    Allsop, T.; Lloyd, G.; Bhamber, R. S.; Hadzievski, L.; Halliday, M.; Webb, D. J.

    2014-05-01

    Cardiovascular health of the human population is a major concern for medical clinicians, with cardiovascular diseases responsible for 48% of all deaths worldwide, according to the World Health Organisation. Therefore the development of new practicable and economical diagnostic tools to scrutinise the cardiovascular health of humans is a major driver for clinicians. We offer a new technique to obtain seismocardiographic signals covering both ballistocardiography (below 20Hz) and audible heart sounds (20Hz upwards). The detection scheme is based upon an array of curvature/displacement sensors using fibre optic long period gratings interrogated using a variation of the derivative spectroscopy interrogation technique.

  6. Reversal of prenatal diazepam-induced deficit in a spatial-object learning task by brief, periodic maternal separation in adult rats.

    PubMed

    Cannizzaro, E; Martire, M; Gagliano, M; Plescia, F; La Barbera, M; Mantia, G; Mineo, A; Cannizzaro, G; Cannizzaro, C

    2005-06-20

    In the rat, prenatal exposure to diazepam (DZ) induces a permanent reduction in GABA/BZ receptor (R) function and behavioural abnormalities. Environmental modifications during early stages of life can influence brain development and induce neurobiological and behavioural changes throughout adulthood. Indeed, a subtle, periodic, postnatal manipulation increases GABA/BZ R activity and produces facilitatory effects on neuroendocrine and behavioural responses. We here investigated the impact of prenatal treatment with DZ on learning performance in adult 3- and 8-month-old male rats and the influence of a brief, periodic maternal separation on the effects exerted by prenatal DZ exposure. Learning performance was examined employing a non-aversive spatial, visual and/or tactile task, the "Can test". Behavioural reactivity, emotional state and fear/anxiety-driven behaviour were also examined using open field (OF), acoustic startle reflex (ASR) and elevated plus-maze (EPM) tests. A single daily injection of DZ (1.5mg/kg, s.c.), over gestational days (GD) 14-20, induced, in an age-independent manner, a severe deficit in learning performance, a decrease in locomotor and explorative activity and an increase in peak amplitude in the ASR. Furthermore, anxiety-driven behaviour in EPM was disrupted. Daily maternal separation for 15 min over postnatal days 2-21 exerted opposite effects in all the paradigms examined. Prenatally DZ-exposed maternal separated rats, in contrast to respective non-separated rats, showed an improvement in learning performance, a decrease in emotionality and a normalization of the exploratory behaviour in EPM. These results suggest that a greater maternal care, induced by separation, can serve as a source for the developing brain to enhance neuronal plasticity and to prevent the behavioural abnormalities induced by prenatal DZ exposure.

  7. Interference induced periodic oscillation of convolutional-surface-plasmon resonance for a metal nanoparticle encapsulated by a dielectric microsphere

    NASA Astrophysics Data System (ADS)

    Sun, Song; Liu, Huizhe; Wu, Lin; Eng Png, Ching; Bai, Ping

    2016-07-01

    A theoretical study is performed on the plasmonic properties of a metal nanoparticle encapsulated by a large microsphere, where the microsphere’s diameter is comparable with or larger than the incident wavelength. Due to interaction between the reflected and refracted waves, we show that a unique optical interference (or whisper-gallery-mode-like) pattern is generated inside the microsphere. Such an interference pattern further interacts with the metal nanoparticle embedded inside, which modifies the spectral response of the metal NP and creates a convolutional-surface-plasmon resonance (cSPR). The peak of resultant cSPR oscillates periodically with respect to the microsphere’s diameter due to the repeated occurrence of the constructive and destructive interferences. Our results also show that the periodicity of oscillation is mainly determined by the microsphere’s refractive index, but is less independent on the metal nanoparticle’s size. These findings might be potentially utilized in designing multi-scale plasmon structures in various applications such as sensors, drug delivery and photocatalysis.

  8. Microwave-induced zero-resistance state in two-dimensional electron systems with unidirectional periodic modulation

    SciTech Connect

    Bykov, A. A.; Rodyakina, E. E.; Latyshev, A. V.; Strygin, I. S.; Goran, A. V.; Kalagin, A. K.

    2016-01-04

    In this study we fabricated lateral superlattices (LSLs) based on the selectively doped GaAs/AlAs heterostructures with a high-mobility two-dimensional (2D) electron gas. The LSLs were formed using the electron-beam lithography and lift-off techniques, which produced a set of metallic strips on top of a heterojunction. The amplitude of the 2D electron gas modulation in the LSL was controlled by the gate voltage applied to the metallic strips. The LSLs with two different periods (a = 200 nm and 500 nm) were used to investigate the influence of microwave radiation with the frequency of 110–150 GHz on the 2D electron transport at the temperature T = 1.6 K in the magnetic field B < 1 T. We have found that zero-resistance states (ZRSs) appear under the microwave radiation in the 2D systems with a unidirectional periodic modulation. These ZRSs are located at the minima of commensurability oscillations.

  9. EphB2 signaling regulates lesion-induced axon sprouting but not critical period length in the postnatal auditory brainstem

    PubMed Central

    2013-01-01

    Background Studies of developmental plasticity may provide insight into plasticity during adulthood, when neural circuitry is less responsive to losses or changes in input. In the mammalian auditory brainstem, globular bushy cell axons of the ventral cochlear nucleus (VCN) innervate the contralateral medial nucleus of the trapezoid body (MNTB) principal neurons. VCN axonal terminations in MNTB, known as calyces of Held, are very large and specialized for high-fidelity transmission of auditory information. Following unilateral deafferentation during postnatal development, VCN axons from the intact side form connections with novel targets, including the ipsilateral MNTB. EphB signaling has been shown to play a role in this process during the first postnatal week, but mechanisms involved in this reorganization during later developmental periods remain unknown. Results We found that EphB2 signaling reduces the number of induced ipsilateral projections to the MNTB after unilateral VCN removal at postnatal day seven (P7), but not after removal of the VCN on one side at P10, after the closure of the critical period for lesion-induced innervation of the ipsilateral MNTB. Conclusions Results from this study indicate that molecular mechanisms involved in the development of circuitry may also play a part in rewiring after deafferentation during development, but do not appear to regulate the length of critical periods for plasticity. PMID:23379484

  10. Breast Cancer Stem Cells Survive Periods of Farnesyl-Transferase Inhibitor-Induced Dormancy by Undergoing Autophagy

    PubMed Central

    Chaterjee, Moumita; van Golen, Kenneth L.

    2011-01-01

    A cancer stem cell has been defined as a cell within a tumor that possesses the capacity to self-renew and to cause the heterogeneous lineages of cancer cells that comprise the tumor. These tumor-forming cells could hypothetically originate from stem, progenitor, or differentiated cells. Previously, we have shown that breast cancer cells with low metastatic potential can be induced into a reversible state of dormancy by farnesyl transferase inhibitors (FTIs). Dormancy was induced by changes in RhoA and RhoC GTPases. Specifically, RhoA was found to be hypoactivated while RhoC was hyperactivated. In the current study we demonstrate that these dormant cells also express certain known stem cell markers such as aldehyde dehydrogenase I (ALDHI) and cluster of differentiation 44 (CD44). We also show that autophagy markers Atg5, Atg12, and LC3-B are expressed in these dormant stem cell-like breast cancer cells. Inhibiting autophagy by inhibitor 3-methyladenine (3-MA) blocked the process of autophagy reversing the dormant phenotype. Further, we show that c-jun NH2 terminal kinase (JNK/SAPK) is upregulated in these dormant stem cell-like breast cancer cells and is responsible for increasing autophagy. PMID:22046561

  11. Hyperlocomotor activity and stress vulnerability during adulthood induced by social isolation after early weaning are prevented by voluntary running exercise before normal weaning period.

    PubMed

    Ishikawa, Junko; Ogawa, Yuko; Owada, Yuji; Ishikawa, Akinori

    2014-05-01

    In rodents, the disruption of social-rearing conditions before normal weaning induces emotional behavioral abnormalities, such as anxiety, motor activity dysregulation, and stress vulnerability. The beneficial effects of exercise after normal weaning on emotional regulation have been well documented. However, effects of exercise before normal weaning on emotion have not been reported. We examined whether voluntary wheel running (R) during social isolation after early weaning (early weaning/isolation; EI) from postnatal day (PD) 14-30 could prevent EI-induced emotional behavioral abnormalities in Sprague-Dawley rats. Compared with control rats reared with their dam and siblings until PD30, rats performed R during EI (EI+R) and EI rats demonstrated greater locomotion and lower grooming activity in the open-field test (OFT) during the juvenile period. Juvenile EI ± R rats showed greater learned helplessness (LH) after exposure to inescapable stress (IS; electric foot shock) than IS-exposed control and EI rats. In contrast, EI rats showed increased locomotion in the OFT and LH after exposure to IS compared with control rats during adulthood; this was not observed in EI ± R rats. Both EI and EI ± R rats exhibited greater rearing activity in the OFT than controls during adulthood. EI did not increase anxiety in the OFT and elevated plus-maze. These results suggested that R during EI until normal weaning prevented some of the EI-induced behavioral abnormalities, including hyperlocomotor activity and greater LH, during adulthood but not in the juvenile period.

  12. Period Cramps

    MedlinePlus

    ... Getting Your Period at School Do Periods Ever End? When Will I Get My Period? ... Nondiscrimination Visit the Nemours Web site. Note: All information on KidsHealth® is for educational purposes ...

  13. Er3+-doped fiber-based Mach-Zehnder interferometer with mechanically induced long-period fiber gratings

    NASA Astrophysics Data System (ADS)

    Pérez-Sánchez, G.; Alvarez-Chavez, J. A.

    2013-09-01

    There are a few semi-conductor, multiple-wavelength, high-performance sources already available for ITU-T channel generation in DWDM systems. The 200 Ghz barrier has imposed a limitation to such sources. An option for overcoming such a limitation is a super-continuum, all fibre source working in the amplified spontaneous emission regime. Furthermore, in this work we propose an Er-doped fiber based Mach-Zehnder interferometer, made with mechanicallyinduced, long-period fiber gratings, which generate a fringe pattern ranging from 1450 to 1650 nm. These characteristics are of great interest for the development of all-fiber devices that could produce and even select a few channels in the 1550nm region, the transmission window of interest for ultra-long haul optical communication systems. A full set of optical characterization and results will be included in the presentation.

  14. Caffeine in the neonatal period induces long-lasting changes in sleep and breathing in adult rats.

    PubMed

    Montandon, Gaspard; Horner, Richard L; Kinkead, Richard; Bairam, Aida

    2009-11-15

    Caffeine is commonly used clinically to treat apnoeas and unstable breathing associated with premature birth. Caffeine antagonizes adenosine receptors and acts as an efficient respiratory stimulant in neonates. Owing to its persistent effects on adenosine receptor expression in the brain, neonatal caffeine administration also has significant effects on maturation of the respiratory control system. However, since adenosine receptors are critically involved in sleep regulation, and sleep also modulates breathing, we tested the hypothesis that neonatal caffeine treatment disrupts regulation of sleep and breathing in the adult rat. Neonatal caffeine treatment (15 mg kg(-1) day(-1)) was administered from postnatal days 3-12. At adulthood (8-10 weeks old), sleep and breathing were measured with a telemetry system and whole-body plethysmography respectively. In adult rats treated with caffeine during the neonatal period, sleep time was reduced, sleep onset latency was increased, and non-rapid eye movement (non-REM) sleep was fragmented compared to controls. Ventilation at rest was higher in caffeine-treated adult rats compared to controls across sleep/wake states. Hypercapnic ventilatory responses were significantly reduced in caffeine-treated rats compared to control rats across sleep/wake states. Additional experiments in adult anaesthetized rats showed that at similar levels of arterial blood gases, phrenic nerve activity was enhanced in caffeine-treated rats. This study demonstrates that administration of caffeine in the neonatal period alters respiratory control system activity in awake and sleeping rats, as well as in the anaesthetized rats, and also has persistent disrupting effects on sleep that are apparent in adult rats.

  15. Sevoflurane exposure during the neonatal period induces long-term memory impairment but not autism-like behaviors.

    PubMed

    Chung, Woosuk; Park, Saegeun; Hong, Jiso; Park, Sangil; Lee, Soomin; Heo, Junyoung; Kim, Daesoo; Ko, Youngkwon

    2015-10-01

    To examine whether neonatal exposure to sevoflurane induces autism-like behaviors in mice. There are continuing reports regarding the potential negative effects of anesthesia on the developing brain. Recently, several studies suggest that neurotoxicity caused by anesthesia may lead to neurodevelopmental impairments. However, unlike reports focusing on learning and memory, there are only a few animal studies focusing on neurodevelopmental disorders after general anesthesia. Therefore, we have focused on autism, a representative neurodevelopmental disorder. Neonatal mice (P6-7) were exposed to a titrated dose of sevoflurane for 6 h. Apoptosis was evaluated by assessing the expression level of cleaved (activated) caspase-3. Autism-like behaviors, general activity, anxiety level, and long-term memory were evaluated with multiple behavioral assays. Western blotting confirmed that neonatal exposure to sevoflurane increased the expression level of activated caspase-3, indicative of apoptosis. Mice exposed to sevoflurane also showed impaired long-term memory in fear tests. However, sevoflurane-exposed mice did not exhibit autism-like features in all of the following assays: social interaction (three-chamber test, caged social interaction), social communication (ultrasonic vocalization test), or repetitive behavior (self-grooming test, digging). There were also no differences in general activity (open field test, home cage activity) and anxiety (open field test, light-dark box) after sevoflurane exposure. Our results confirm previous studies that neonatal sevoflurane exposure causes neurodegeneration and long-term memory impairment in mice. However, sevoflurane did not induce autism-like features. Our study suggests that mice are more vulnerable to long-term memory deficits than autism-like behaviors after exposure to sevoflurane. © 2015 John Wiley & Sons Ltd.

  16. Oxytocin- and aluminium fluoride-induced phospholipase C activity and prostaglandin F2 alpha secretion during the ovine luteolytic period.

    PubMed

    Graf, G A; Burns, P D; Silvia, W J

    1998-03-01

    A series of studies was conducted to characterize changes in components of the cell signalling cascade that mediates oxytocin-induced prostaglandin F2 alpha (PGF2 alpha) synthesis at the onset of luteolysis in sheep. In the first experiment, caruncular tissue was dissected from 20 ewes on days 12-15 of the oestrous cycle, and incubated for the measurement of phospholipase C (PLC) activity or secretion of PGF2 alpha. Activation of GTP-binding proteins with aluminium fluoride stimulated both inositol phosphate accumulation and PGF2 alpha secretion on all days examined. However, oxytocin did not stimulate PLC activity or PGF2 alpha accumulation until day 13. While the ability of oxytocin to stimulate PLC activity increased after day 13, oxytocin-induced PGF2 alpha secretion declined slightly from day 13 to 15, suggesting that cell signalling components downstream from PLC modulate the response to oxytocin after day 13. Oxytocin failed to stimulate PGF2 alpha synthesis on day 14 after oestrus. Secretion of endogenous luteal oxytocin may have rendered uterine tissues collected on day 14 refractory to oxytocin in vitro. Therefore, a second study was conducted in ovariectomized, steroid replaced ewes. Ovarian steroids were administered to mimic endogenous changes in progesterone and oestradiol. The temporal patterns of PGF2 alpha synthesis in response to oxytocin and pharmacological agents were similar to uterine tissues from cyclic ewes in the first experiment; however, the magnitude of the response was less. These data suggest that oxytocin receptors are absent or are not coupled to PLC until day 13 after oestrus.

  17. Early Exposure of Infants to GI Nematodes Induces Th2 Dominant Immune Responses Which Are Unaffected by Periodic Anthelminthic Treatment

    PubMed Central

    Wright, Victoria J.; Ame, Shaali Makame; Haji, Haji Said; Weir, Rosemary E.; Goodman, David; Pritchard, David I.; Ramsan Mohamed, Mahdi; Haji, Hamad Juma; Tielsch, James M.; Stoltzfus, Rebecca J.; Bickle, Quentin D.

    2009-01-01

    We have previously shown a reduction in anaemia and wasting malnutrition in infants <3 years old in Pemba Island, Zanzibar, following repeated anthelminthic treatment for the endemic gastrointestinal (GI) nematodes Ascaris lumbricoides, hookworm and Trichuris trichiura. In view of the low intensity of worm infections in this age group, this was unexpected, and it was proposed that immune responses to the worms rather than their direct effects may play a significant role in morbidity in infants and that anthelminthic treatment may alleviate such effects. Therefore, the primary aims of this study were to characterise the immune response to initial/early GI nematode infections in infants and the effects of anthelminthic treatment on such immune responses. The frequency and levels of Th1/Th2 cytokines (IL-5, IL-13, IFN-γ and IL-10) induced by the worms were evaluated in 666 infants aged 6–24 months using the Whole Blood Assay. Ascaris and hookworm antigens induced predominantly Th2 cytokine responses, and levels of IL-5 and IL-13 were significantly correlated. The frequencies and levels of responses were higher for both Ascaris positive and hookworm positive infants compared with worm negative individuals, but very few infants made Trichuris-specific cytokine responses. Infants treated every 3 months with mebendazole showed a significantly lower prevalence of infection compared with placebo-treated controls at one year following baseline. At follow-up, cytokine responses to Ascaris and hookworm antigens, which remained Th2 biased, were increased compared with baseline but were not significantly affected by treatment. However, blood eosinophil levels, which were elevated in worm-infected children, were significantly lower in treated children. Thus the effect of deworming in this age group on anaemia and wasting malnutrition, which were replicated in this study, could not be explained by modification of cytokine responses but may be related to eosinophil function

  18. Period meter for reactors

    DOEpatents

    Rusch, Gordon K.

    1976-01-06

    An improved log N amplifier type nuclear reactor period meter with reduced probability for noise-induced scrams is provided. With the reactor at low power levels a sampling circuit is provided to determine the reactor period by measuring the finite change in the amplitude of the log N amplifier output signal for a predetermined time period, while at high power levels, differentiation of the log N amplifier output signal provides an additional measure of the reactor period.

  19. Pharmacologically Induced/Exacerbated Restless Legs Syndrome, Periodic Limb Movements of Sleep, and REM Behavior Disorder/REM Sleep Without Atonia: Literature Review, Qualitative Scoring, and Comparative Analysis

    PubMed Central

    Hoque, Romy; Chesson, Andrew L.

    2010-01-01

    Background: Pharmacologically induced/exacerbated restless legs syndrome (RLS), periodic limb movements in sleep (PLMS), and REM behavior disorder/REM sleep without atonia (RSWA) are increasingly recognized in clinical sleep medicine. A scoring system to evaluate the literature was created and implemented. The aim was to identify the evidence with the least amount of confound, allowing for more reliable determinations of iatrogenic etiology. Methods: Points were provided for the following criteria: manuscript type (abstract, peer-reviewed paper); population size studied (large retrospective study, small case series, case report); explicitly stated dosage timing; identification of peak symptoms related to time of medication administration (i.e., medication was ingested in the evening or at bedtime); initiation of a treatment plan; symptoms subsided or ceased with decreased dosage or drug discontinuation (for RLS articles only); negative personal history for RLS prior to use of the medication; exclusion of tobacco/alcohol/excessive caffeine use; exclusion of sleep disordered breathing by polysomnography (PSG); and PSG documentation of presence or absence of PLMS. For RLS and PLMS articles were also given points for the following criteria: each 2003 National Institutes of Health (NIH) RLS criteria met; exclusion of low serum ferritin; and exclusion of peripheral neuropathy by neurological examination. Results: Thirty-two articles on drug-induced RLS, 6 articles on drug-induced PLMS, and 15 articles on drug-induced RBD/RSWA were analyzed. Conclusion: Based on scores ≥ 10 and trials of medication reduction/cessation, the strongest evidence available for drug induced RLS are for the following drugs: escitalopram; fluoxetine; L-dopa/carbidopa and pergolide; L-thyroxine; mianserin; mirtazapine; olanzapine; and tramadol. Since none of the PLMS articles assessed PLMI in trials of medication reduction/cessation, the strongest evidence based on scores ≥ 10 are for the

  20. Expression of amphetamine-induced behavioral sensitization after short- and long-term withdrawal periods: participation of mu- and delta-opioid receptors.

    PubMed

    Magendzo, Karin; Bustos, Gonzalo

    2003-03-01

    Repeated amphetamine administration results in behavioral sensitization, an enduring behavioral transformation expressed after short and long periods of withdrawal. To investigate the participation of the opioid system in amphetamine-induced behavioral sensitization, we studied the effect of naloxone, an opioid receptor antagonist, on the expression of behavioral sensitization tested after short- (2 days) and long-term (14 days) withdrawal periods. In addition, using quantitative competitive RT-PCR, we examined the levels of mu-opioid receptor (MOR) and delta-opioid receptor (DOR) mRNA in the nucleus accumbens shell (NAcSh) and ventral tegmental area (VTA) of behaviorally sensitized rats, at these two withdrawal times. This study showed that whereas naloxone did not modify the expression of behavioral sensitization tested after 2 days of withdrawal, it completely blocked the expression when tested after 14 days of withdrawal. DOR and MOR mRNA levels were not modified in the NAcSh of rats expressing behavioral sensitization after 2 or 14 days of withdrawal. Conversely, DOR and MOR mRNA levels were elevated in the VTA of animals expressing behavioral sensitization after 2 days of withdrawal. However, whereas DOR mRNA returned to control levels, MOR mRNA levels remained elevated in animals expressing behavioral sensitization after 14 days of withdrawal. These results indicate a striking difference between the role played by opioid receptors in the expression of amphetamine-induced behavioral sensitization, when tested after short- or long-term withdrawal periods. In addition, our results support the notion that repeated amphetamine-induced changes in opioid receptor expression may contribute to the perpetuation of psychostimulant abuse and/or relapse.

  1. Fasting during the suckling-weaning transient period of rats induces inflammatory gene expression in the adipose tissue and peripheral leukocytes.

    PubMed

    Honma, Kazue; Mawatari, Riko; Iikeda, Misa; Mochizuki, Kazuki; Goda, Toshinao

    2016-01-01

    Nutritional deficiency during developmental stages could be associated with subsequent development of inflammation-related metabolic abnormalities. In this study, we examined the effects of a 3-d fast during the suckling-weaning transient period of rats, and subsequent intake of high-fat-high-sucrose (HF) and low-fat-high-starch (LF) diets in adulthood, on the expression of inflammatory genes in adipose tissue and peripheral leukocytes. Male Sprague-Dawley rats were deprived of food for 3 d during the suckling-weaning transient period, and were subsequently fed an HF or LF diet for 14 wk from 17 wk of age. Serum monocyte chemoattractant protein-1 (MCP-1) concentration and mRNA levels of inflammatory genes in mesenteric adipose tissues were assessed at 31 wk of age. The mRNA levels of inflammatory genes at 0 h and 2 h after oral glucose load at 30 wk of age in peripheral leukocytes were measured. Fasting induced circulating MCP-1 protein in rats fed an LF diet but not an HF diet. The HF diet induced high mRNA levels of tumor necrosis factor-α, interleukin-1β, and S100 proteins in peripheral leukocytes at 2 h after glucose load in fasted rats when compared with controls. Expression of CD11c, an activated macrophage marker, was induced in the fasted group given an HF diet during adulthood. Fasting rats during the suckling-weaning transient period and an HF diet intake during adulthood enhance inflammation by promoting the expression of inflammatory genes in adipose tissue and peripheral leukocytes. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Mapping the structural order of laser-induced periodic surface structures in thin polymer films by microfocus beam grazing incidence small-angle X-ray scattering.

    PubMed

    Martín-Fabiani, Ignacio; Rebollar, Esther; García-Gutiérrez, Mari Cruz; Rueda, Daniel R; Castillejo, Marta; Ezquerra, Tiberio A

    2015-02-11

    In this work we present an accurate mapping of the structural order of laser-induced periodic surface structures (LIPSS) in spin-coated thin polymer films, via a microfocus beam grazing incidence small-angle X-ray scattering (μGISAXS) scan, GISAXS modeling, and atomic force microscopy imaging all along the scanned area. This combined study has allowed the evaluation of the effects on LIPSS formation due to nonhomogeneous spatial distribution of the laser pulse energy, mapping with micrometric resolution the evolution of the period and degree of structural order of LIPSS across the laser beam diameter in a direction perpendicular to the polarization vector. The experiments presented go one step further toward controlling nanostructure formation in LIPSS through a deep understanding of the parameters that influence this process.

  3. In situ monitoring of laser-induced periodic surface structures formation on polymer films by grazing incidence small-angle X-ray scattering.

    PubMed

    Rebollar, Esther; Rueda, Daniel R; Martín-Fabiani, Ignacio; Rodríguez-Rodríguez, Álvaro; García-Gutiérrez, Mari-Cruz; Portale, Giuseppe; Castillejo, Marta; Ezquerra, Tiberio A

    2015-04-07

    The formation of laser-induced periodic surface structures (LIPSS) on model spin-coated polymer films has been followed in situ by grazing incidence small-angle X-ray scattering (GISAXS) using synchrotron radiation. The samples were irradiated at different repetition rates ranging from 1 up to 10 Hz by using the fourth harmonic of a Nd:YAG laser (266 nm) with pulses of 8 ns. Simultaneously, GISAXS patterns were acquired during laser irradiation. The variation of both the GISAXS signal with the number of pulses and the LIPSS period with laser irradiation time is revealing key kinetic aspects of the nanostructure formation process. By considering LIPSS as one-dimensional paracrystalline lattice and using a correlation found between the paracrystalline disorder parameter, g, and the number of reflections observed in the GISAXS patterns, the variation of the structural order of LIPSS can be assessed. The role of the laser repetition rate in the nanostructure formation has been clarified. For high pulse repetition rates (i.e., 10 Hz), LIPSS evolve in time to reach the expected period matching the wavelength of the irradiating laser. For lower pulse repetition rates LIPSS formation is less effective, and the period of the ripples never reaches the wavelength value. Results support and provide information on the existence of a feedback mechanism for LIPSS formation in polymer films.

  4. Application of a characteristic periods-based (CPB) approach to estimate earthquake-induced displacements of landslides through dynamic numerical modelling

    NASA Astrophysics Data System (ADS)

    Martino, S.; Lenti, L.; Delgado, J.; Garrido, J.; Lopez-Casado, C.

    2016-07-01

    The interaction between seismic waves and slopes is an important topic to provide reliable scenarios for earthquake-(re)triggered landslides. The physical properties of seismic waves as well as slope topography and geology can significantly modify the local seismic response, influencing landslide triggering. A novel approach is here applied to two case studies in Andalusia (southern Spain) for computing the expected earthquake-induced displacements of existing landslide masses. Towards this aim, dynamic stress-strain numerical modelling was carried out using a selection of seismic signals characterized by different spectral content and energy. In situ geophysical measurements, consisting of noise records and temporary seismometric arrays, were carried out to control the numerical outputs in terms of local seismic response. The results consist of relationships between the characteristic period, Tm, of the seismic signals and the characteristic periods of the landslide masses, related to the thickness (Ts) and length (Tl), respectively. These relationships show that the larger the horizontal dimension (i.e. length of landslide) of a landslide is, the more effective the contribution (to the resulting coseismic displacement) of the long-period seismic waves is, as the maximum displacements are expected for a low Tm at each energy level of the input. On the other hand, when the local seismic response mainly depends on stratigraphy (i.e. landslide thickness), the maximum expected displacements occur close to the resonance period of the landslide, except for high-energy seismic inputs.

  5. Regulation of cAMP-induced arylalkylamine N-acetyltransferase, Period1, and MKP-1 gene expression by mitogen-activated protein kinases in the rat pineal gland.

    PubMed

    Chansard, Mathieu; Iwahana, Eiko; Liang, Jian; Fukuhara, Chiaki

    2005-10-03

    In rodent pineal glands, sympathetic innervation, which leads to norepinephrine release, is a key process in the circadian regulation of physiology and certain gene expressions. It has been shown that gene expression of the rate-limiting enzyme in the melatonin synthesis arylalkylamine N-acetyltransferase (Aa-Nat), circadian clock gene Period1, and mitogen-activated protein kinase (MAPK) phosphtase-1 (MKP-1), is controlled mainly by a norepinephrine-beta-adrenergic receptor-cAMP signaling cascade in the rat pineal gland. To further dissect the signaling cascades that regulate those gene expressions, we examined whether MAPKs are involved in cAMP-induced gene expression. Western blot and immunohistochemical analyses showed that one of the three MAPKs, c-Jun N-terminal kinase (JNK), was expressed in the pineal, and was phosphorylated by cAMP analogue stimulation with a peak 20 min after start of the stimulation, in vitro. A specific JNK inhibitor SP600125 (Anthra[1,9-cd]pyrazol-6(2H)-one1,9-pyrazoloanthrone), but not its negative control (N1-Methyl-1,9-pyrazoloanthrone), significantly reduced cAMP-stimulated Aa-Nat, Period1, and MKP-1 mRNA levels. Although another MAPK, p38(MAPK), has also been shown to be activated by cAMP stimulation, a p38(MAPK) inhibitor, SB203580 (4-(4-Fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-imidazole, HCl), showed no effect on cAMP-induced Aa-Nat and Period1 mRNA levels; whereas SB203580, but not its negative analogue SB202474 (4-Ethyl-2(p-methoxyphenyl)-5-(4'-pyridyl)-IH-imidazole, DiHCl), significantly reduced cAMP-induced MKP-1 mRNA levels. Taken together, our data suggest that cAMP-induced Aa-Nat and Period1 are likely to be mediated by activation of JNK, whereas MKP-1 may be mediated by both p38(MAPK) and JNK activations.

  6. The Comparisons of Cerebral Hemodynamics Induced by Obstructive Sleep Apnea with Arousal and Periodic Limb Movement with Arousal: A Pilot NIRS Study

    PubMed Central

    Zhang, Zhongxing; Schneider, Maja; Laures, Marco; Qi, Ming; Khatami, Ramin

    2016-01-01

    Obstructive sleep apnea syndrome (OSA) and restless legs syndrome (RLS) with periodic limb movement during sleep (PLMS) are two sleep disorders characterized by repetitive respiratory or movement events associated with cortical arousals. We compared the cerebral hemodynamic changes linked to periodic apneas/hypopneas with arousals (AHA) in four OSA-patients with periodic limb movements (PLMA) with arousals in four patients with RLS-PLMS using near-infrared spectroscopy (NIRS). AHA induced homogenous pattern of periodic fluctuations in oxygenated (HbO2) and deoxygenated (HHb) hemoglobin, i.e., the decrease of HbO2 was accompanied by an increase of HHb during the respiratory event and resolved to reverse pattern when cortical arousal started. Blood volume (BV) showed the same pattern as HHb but with relative smaller amplitude in most of the AHA events.These changing patterns were significant as Wilcoxon signed-rank tests gave p < 0.001 when comparing the area under the curve of these hemodynamic parameters to zero. By contrast, in PLMA limb movements induced periodic increments in HbO2 and BV (Wilcoxon signed-rank tests, p < 0.001), but HHb changed more heterogeneously even during the events coming from the same patient. Heart rate (HR) also showed different patterns between AHA and PLMA. It significantly decreased during the respiratory event (Wilcoxon signed-rank test, p < 0.001) and then increased after the occurrence of cortical arousal (Wilcoxon signed-rank test, p < 0.001); while in PLMA HR first increased preceding the occurrence of cortical arousal (Wilcoxon signed-rank test, p < 0.001) and then decreased. The results of this preliminary study show that both AHA and PLMA induce changes in cerebral hemodynamics. The occurrence of cortical arousal is accompanied by increased HR in both events, but by different BV changes (i.e., decreased/increased BV in AHA/PLMA, respectively). HR changes may partially account for the increased cerebral hemodynamics during PLMA

  7. Quantum critical scaling for field-induced quantum phase transition in a periodic Anderson-like model polymer chain

    NASA Astrophysics Data System (ADS)

    Ding, L. J.; Zhong, Y.

    2017-07-01

    The quantum phase transition and thermodynamics of a periodic Anderson-like polymer chain in a magnetic field are investigated by Green's function theory. The T-h phase diagram is explored, wherein a crossover temperature T∗ denoting the gapless phase crossover into quantum critical regimes, smoothly connects near the critical fields to the universal linear line T∗ ∼ (h - hc,s), and ends at hc,s, providing a new route to capture quantum critical point (QCP). The quantum critical scaling around QCPs is demonstrated by analyzing magnetization, specific heat and Grüneisen parameter Γh, which provide direct access to distill the power-law critical exponents (β, δ and α) obeying the critical scaling relation α + β(1 + δ) = 2, analogous to the quantum spin system. Furthermore, scaling hypothesis equations are proposed to check the scaling analysis, for which all the data collapse onto a single curve or two independent branches for the plot against an appropriate scaling variable, indicating the self-consistency and reliability of the obtained critical exponents.

  8. Periodic (18.6-year) and cyclic (11-year) induced drought and flood in western North America

    NASA Astrophysics Data System (ADS)

    Currie, Robert Guinn

    1984-08-01

    Analysis of 102 reent tree-ring chronologies confirms earlier evidence for 18.6-year tidal drought/flood induction (Currie, 1981d, 1984b) and led to discovery of 11-year solar cycle induced drought/flood for western North America. Bistable phasing in terms of geography is found with epohs of maximum in lunar nodal 18.6-year drought in western Canada out of phase with those in the western United States and northern Mexico the past two centuries. Solar drought/flood induction provides one mechanism that appears to have modulated the intensity of nodal drought/flood induction in the latter region, most recently at epoch 1936.1. The above results were confirmed by analysis of yet more voluminous data, and they le to discovery of an example of bistable phasing with respect to time in western Canada during the 17th century. The implications for agriculture of such phenomena, which occur worldwide (Currie, 1984c), are surveyed.

  9. Differential patterns of cortical reorganization following constraint-induced movement therapy during early and late period after stroke

    PubMed Central

    Sawaki, Lumy; Butler, Andrew J.; Leng, Xiaoyan; Wassenaar, Peter A.; Mohammad, Yousef; Blanton, Sarah; Sathian, K.; Nichols-Larsen, Deborah S.; Wolf, Steven L.; Good, David C.; Wittenberg, George F.

    2015-01-01

    OBJECTIVE Constraint-induced movement therapy (CIMT) leads to improvement in upper extremity movement and cortical reorganization after stroke. Direct comparison of the differential degree of cortical reorganization according to chronicity in stroke subjects receiving CIMT has not been performed and was the purpose of this study. We hypothesized that a higher degree of cortical reorganization would occur in the early (less than 9 months post-stroke) compared to the late group (more than 12 months post-stroke). METHODS 17 early and 9 late subjects were enrolled. Each subject was evaluated using transcranial magnetic stimulation (TMS) and the Wolf Motor Function Test (WMFT) and received CIMT for 2 weeks. RESULTS The early group showed greater improvement in WMFT compared with the late group. TMS motor maps showed persistent enlargement in both groups. The map shifted posteriorly in the late stroke group. CONCLUSION CIMT appears to lead to greater improvement in motor function in early phase after stroke. Greater cortical reorganization associated with shift in map position occurred in late group. SIGNIFICANCE The contrast between larger functional gains in the early group vs larger map expansion in the late group may indicate that cortical reorganization depends upon different neural substrates in the late stroke group. PMID:25227542

  10. Induced magnetization and power loss for a periodically driven system of ferromagnetic nanoparticles with randomly oriented easy axes

    NASA Astrophysics Data System (ADS)

    Denisov, S. I.; Lyutyy, T. V.; Pedchenko, B. O.; Hryshko, O. M.

    2016-07-01

    We study the effect of an elliptically polarized magnetic field on a system of noninteracting, single-domain ferromagnetic nanoparticles characterized by a uniform distribution of easy axis directions. Our main goal is to determine the average magnetization of this system and the power loss in it. In order to calculate these quantities analytically, we develop a general perturbation theory for the Landau-Lifshitz-Gilbert (LLG) equation and find its steady-state solution for small magnetic field amplitudes. On this basis, we derive the second-order expressions for the average magnetization and power loss, investigate their dependence on the magnetic field frequency, and analyze the role of subharmonic resonances resulting from the nonlinear nature of the LLG equation. For arbitrary amplitudes, the frequency dependence of these quantities is obtained from the numerical solution of this equation. The impact of transitions between different regimes of regular and chaotic dynamics of magnetization, which can be induced in nanoparticles by changing the magnetic field frequency, is examined in detail.

  11. Exploring global changes in nitrogen and phosphorus cycles in agriculture induced by livestock production over the 1900–2050 period

    PubMed Central

    Bouwman, Lex; Goldewijk, Kees Klein; Van Der Hoek, Klaas W.; Beusen, Arthur H. W.; Van Vuuren, Detlef P.; Willems, Jaap; Rufino, Mariana C.; Stehfest, Elke

    2013-01-01

    Crop-livestock production systems are the largest cause of human alteration of the global nitrogen (N) and phosphorus (P) cycles. Our comprehensive spatially explicit inventory of N and P budgets in livestock and crop production systems shows that in the beginning of the 20th century, nutrient budgets were either balanced or surpluses were small; between 1900 and 1950, global soil N surplus almost doubled to 36 trillion grams (Tg)·y−1 and P surplus increased by a factor of 8 to 2 Tg·y−1. Between 1950 and 2000, the global surplus increased to 138 Tg·y−1 of N and 11 Tg·y−1 of P. Most surplus N is an environmental loss; surplus P is lost by runoff or accumulates as residual soil P. The International Assessment of Agricultural Knowledge, Science, and Technology for Development scenario portrays a world with a further increasing global crop (+82% for 2000–2050) and livestock production (+115%); despite rapidly increasing recovery in crop (+35% N recovery and +6% P recovery) and livestock (+35% N and P recovery) production, global nutrient surpluses continue to increase (+23% N and +54% P), and in this period, surpluses also increase in Africa (+49% N and +236% P) and Latin America (+75% N and +120% P). Alternative management of livestock production systems shows that combinations of intensification, better integration of animal manure in crop production, and matching N and P supply to livestock requirements can effectively reduce nutrient flows. A shift in human diets, with poultry or pork replacing beef, can reduce nutrient flows in countries with intensive ruminant production. PMID:21576477

  12. Sensitive and critical periods in the development of handling induced seizures in mice lacking synapsins: differences between synapsin I and synapsin II knockouts.

    PubMed

    Etholm, Lars; Bahonjic, Elma; Heggelund, Paul

    2013-09-01

    Mice lacking either synapsin I or synapsin II develop handling induced seizures from around two months of age. In mice lacking synapsin I (synapsin 1 knock-out mice, Syn1KO mice) such seizures can either consist of mild myoclonic jerks or of fully developed generalized tonic-clonic seizures, and the two seizure types are quite evenly distributed. In mice lacking synapsin II (synapsin 2 knock-out mice, Syn2KO mice) all seizures are in the form of generalized tonic-clonic seizures. Through the use of specialized animal rearing procedures whereby human-animal interaction was minimized (minimal handling procedures), this study investigated effects of handling also prior to the emergence of actual seizures. The effect of minimal handling procedures was significant in both genotypes, but most pronounced in Syn1KO mice. In this genotype, minimal handling reduced the frequency of mild seizures, and completely eliminated generalized tonic-clonic seizures when the animals were tested with regular handling at 4 1/2 months of age. Neither seizure frequency nor generalized tonic-clonic seizures could be re-established through regular handling from 4 1/2 to 8 months. This suggests that the period up to 4 1/2 months constitute a sensitive period for seizures in general, and a critical period for generalized tonic-clonic seizures in this genotype. In Syn2KO mice minimal handling did not remove generalized tonic-clonic seizures, as such seizures were present when handling was introduced at 4 1/2 months. We found an initial reduction of seizure frequency, but the seizure frequency eventually reached levels seen in mice kept under regular handling regimes. Thus, it is unlikely that the period up to 4 1/2 months is a sensitive period in the Syn2KO genotype. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Assessment and formation mechanism of laser-induced periodic surface structures on polymer spin-coated films in real and reciprocal space.

    PubMed

    Rebollar, Esther; Pérez, Susana; Hernández, Jaime J; Martín-Fabiani, Ignacio; Rueda, Daniel R; Ezquerra, Tiberio A; Castillejo, Marta

    2011-05-03

    In this work we evaluate the potential of grazing incidence X-ray scattering techniques in the investigation of laser-induced periodic surface structures (LIPSSs) in a series of strongly absorbing model spin-coated polymer films which are amorphous, such as poly(ethylene terephthalate), poly(trimethylene terephthalate), and poly(carbonate bisphenol A), and in a weaker absorbing polymer, such as semicrystalline poly(vinylidene fluoride), over a narrow range of fluences. Irradiation was performed with pulses of 6 ns at 266 nm, and LIPSSs with period lengths similar to the laser wavelength and parallel to the laser polarization direction are formed by devitrification of the film surface at temperatures above the characteristic glass transition temperature of the polymers. No crystallization of the surface is induced by laser irradiation, and crystallinity of the material prevents LIPSS formation. The structural information obtained by both atomic force microscopy and grazing incidence small-angle X-ray scattering (GISAXS) correlates satisfactorily. Comparison of experimental and simulated GISAXS patterns suggests that LIPSSs can be well described considering a quasi-one-dimensional paracrystalline lattice and that irradiation parameters have an influence on the order of such a lattice.

  14. Effect of nonlinearity on the dynamics of Bragg-induced optical Rabi oscillations in a one-dimensional periodic photonic structure

    NASA Astrophysics Data System (ADS)

    Brandão, P. A.; Cavalcanti, S. B.

    2017-10-01

    Propagation of wide optical beams in transverse periodic lattices have been reported to induce power oscillations between Fourier modes related by the Bragg resonance condition, resulting from the coupling between the beam and the periodic structure. These oscillations have been referred to as Rabi optical oscillations due to the analogy with matter Rabi oscillations. In this work, we investigate the behavior of Bragg-induced Rabi-type oscillations of a multimode Gaussian beam in the presence of optical nonlinearity. We find a combination of oscillation and spectrum broadening under both self-focusing and self-defocusing nonlinearities, in the sense that the oscillations are maintained while the spectrum is broadened and therefore partially transferred to the twin frequency. For intense self-focusing nonlinearities a complete leak of the initial mode profile to other modes is rapidly attained so that no oscillation is observed. In contrast, for intense self-defocusing nonlinearities the redistribution rate is so dramatic that oscillations cease and power only fades away.

  15. Twist Sensitivity of Cladding-Mode Resonances and Its Cross-Sensitivity to Strain and Temperature in a Mechanically Induced Long-Period Fiber Grating

    NASA Astrophysics Data System (ADS)

    Nair, Anitha S.; Sudeep Kumar, V. P.; Joe, Hubert

    2014-09-01

    Twist sensitivity of cladding-mode resonances in a mechanically induced long-period fiber grating formed over a single-mode fiber is experimentally demonstrated and theoretically analyzed. Of the two usual cladding-mode resonances corresponding to LP11 and LP12, higher-order mode LP12 is more sensitive to twist in comparison with the lower-order mode LP11. The extent of down-shifting of resonant wavelengths depends on twist-induced circular birefringence and the modal field distribution of the cladding-modes inside the fiber. When the fiber is severely twisted to 3.5 rad/cm, a shift sensitivity is observed of 1 nm/(rad/cm) for the LP11 mode and 4.23 nm/(rad/cm) for the LP12 mode. The fiber breaks when the twist rate exceeds 3.5 rad/cm. In comparison with LP12, the LP11 resonance is almost independent of the axial strain variation with an ultra-low sensitivity of 0.18 pm/με, and it is also almost insensitive to the temperature variation with a coefficient of 35 pm/°C. Forming the LP11 resonance far away from its cut-off wavelength, a widely tunable band-pass filter is also demonstrated with a very high twist sensitivity of 8.75 nm/(rad/cm) and negligible cross-sensitivity to strain and temperature. The experimental and theoretical results are very useful in selecting sensitive and stable cladding-mode resonances in the design of new mechanically induced long-period fiber gratings based torsion sensors and tunable band-pass filters.

  16. Formation of thermochemical laser-induced periodic surface structures on Ti films by a femtosecond IR Gaussian beam: regimes, limiting factors, and optical properties

    NASA Astrophysics Data System (ADS)

    Dostovalov, A. V.; Korolkov, V. P.; Babin, S. A.

    2017-01-01

    The formation of thermochemical laser-induced periodic surface structures (TLIPSS) on 400-nm Ti films deposited onto a glass substrate is investigated under irradiation by a femtosecond laser with a wavelength of 1026 nm, pulse duration of 232 fs, repetition rate of 200 kHz, and with different spot sizes of 4-21 μm. The optimal fluence for TLIPSS formation reduces monotonously with increasing the spot diameter in the range. It is found that the standard deviation of the TLIPSS period depends significantly on the beam size and reaches approximately 2% when the beam diameter is in the range of 10-21 μm. In addition to TLIPSS formation with the main period slightly smaller than the laser wavelength, an effect of TLIPSS spatial frequency doubling is detected. The optical properties of TLIPSS (reflection spectrum and diffraction efficiency at different incident angles and polarizations) are investigated and compared with theoretical ones to give a basis for the development of an optical inspecting method. The refractive index and absorption coefficient of oxidized ridges of the TLIPSS are theoretically estimated by simulation of the experimental reflection spectrum in the zeroth diffraction order.

  17. Effect of low-frequency repetitive transcranial magnetic stimulation combined with physical therapy on L-dopa-induced painful off-period dystonia in Parkinson's disease.

    PubMed

    Kodama, Mitsuhiko; Kasahara, Takashi; Hyodo, Masaki; Aono, Koji; Sugaya, Mutsumi; Koyama, Yuji; Hanayama, Kozo; Masakado, Yoshihisa

    2011-02-01

    Previous research has shown that low-frequency repetitive transcranial magnetic stimulation over the primary motor area and supplementary motor area can reduce L-dopa-induced dyskinesias in Parkinson's disease; however, it involved only patients with peak-dose or diphasic dyskinesia. We report a case of a patient with severely painful off-period dystonia in the unilateral lower limb who underwent 0.9-Hz subthreshold repetitive transcranial magnetic stimulation over contralateral primary motor area and supplementary motor area. Repetitive transcranial magnetic stimulation over the primary motor area significantly reduced the painful dystonia and walking disturbances but repetitive transcranial magnetic stimulation over the supplementary motor area did not. The cortical silent period also prolonged after repetitive transcranial magnetic stimulation over the primary motor area. At 5 mos of approximately once a week repetitive transcranial magnetic stimulation over the primary motor area, the Unified Parkinson's Disease Rating Scale motor score also improved. This report shows that repetitive transcranial magnetic stimulation over the inhibitory primary motor area can be useful for rehabilitating patients with Parkinson's disease with off-period dystonia and suggests that this treatment should be further verified in such patients.

  18. Editor's Highlight: Periodic Exposure to Smartphone-Mimic Low-Luminance Blue Light Induces Retina Damage Through Bcl-2/BAX-Dependent Apoptosis.

    PubMed

    Lin, Cheng-Hui; Wu, Man-Ru; Li, Ching-Hao; Cheng, Hui-Wen; Huang, Shih-Hsuan; Tsai, Chi-Hao; Lin, Fan-Li; Ho, Jau-Der; Kang, Jaw-Jou; Hsiao, George; Cheng, Yu-Wen

    2017-05-01

    Blue light-induced phototoxicity plays an important role in retinal degeneration and might cause damage as a consequence of smartphone dependency. Here, we investigated the effects of periodic exposure to blue light-emitting diode in a cell model and a rat retinal damage model. Retinal pigment epithelium (RPE) cells were subjected to blue light in vitro and the effects of blue light on activation of key apoptotic pathways were examined by measuring the levels of Bcl-2, Bax, Fas ligand (FasL), Fas-associated protein with death domain (FADD), and caspase-3 protein. Blue light treatment of RPE cells increased Bax, cleaved caspase-3, FasL, and FADD expression, inhibited Bcl-2 and Bcl-xL accumulation, and inhibited Bcl-2/Bax association. A rat model of retinal damage was developed with or without continuous or periodic exposure to blue light for 28 days. In this rat model of retinal damage, periodic blue light exposure caused fundus damage, decreased total retinal thickness, caused atrophy of photoreceptors, and injured neuron transduction in the retina. © The Author 2017. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  19. Removal of Infragravity-Wave-Induced Long-Period Noise from OBS Data and Inversion for Crustal Structure Offshore Eastern Taiwan

    NASA Astrophysics Data System (ADS)

    Kuo, B.; Lin, C.; Hsiao, N.; Liang, W.

    2013-12-01

    Vertical ocean-bottom seismometer (OBS) data at frequencies < 0.05 Hz are contaminated by noise exerted from ocean waves, especially the infragravity waves. We constructed the transfer function between pressure and velocity data of OBSs deployed in Taiwan waters and removed the pressure-induced noise from seismic recordings. Three broadband OBSs S002, S005, and S004 were deployed at 1750, 1900, and 4500 m water depth each for 10 months, and a cabled, shallow-buried sensor EOS1 was installed at 300 m seafloor since late 2011. Removing long-period noise for these OBSs improves the identification of teleseismic phases P, S, Pdiff, and PKIKP which were otherwise unidentifiable. For EOS1, infragravity waves completely mask the P and S waveforms for local events in the period range for CMT solution, i.e., 10-40 s. Application of transfer function yielded clean, prominent P and S waveforms at these periods and aids in the CMT determination of small events jointly with land stations. EOS1 is situated on the Ryukyu ridge 45 km off the NE coast of Taiwan. We are performing inversion of the compliance function for EOS1 for the crustal structure beneath the station.

  20. Chronic Sleep Fragmentation During the Sleep Period Induces Hypothalamic Endoplasmic Reticulum Stress and PTP1b-Mediated Leptin Resistance in Male Mice

    PubMed Central

    Hakim, Fahed; Wang, Yang; Carreras, Alba; Hirotsu, Camila; Zhang, Jing; Peris, Eduard; Gozal, David

    2015-01-01

    Background: Sleep fragmentation (SF) is highly prevalent and may constitute an important contributing factor to excessive weight gain and the metabolic syndrome. Increased endoplasmic reticulum (ER) stress and activation of the unfolded protein response (UPR) leading to the attenuation of leptin receptor signaling in the hypothalamus leads to obesity and metabolic dysfunction. Methods: Mice were exposed to SF and sleep control (SC) for varying periods of time during which ingestive behaviors were monitored. UPR pathways and leptin receptor signaling were assessed in hypothalami. To further examine the mechanistic role of ER stress, changes in leptin receptor (ObR) signaling were also examined in wild-type mice treated with the ER chaperone tauroursodeoxycholic acid (TUDCA), as well as in CHOP −/+ transgenic mice. Results: Fragmented sleep in male mice induced increased food intake starting day 3 and thereafter, which was preceded by increases in ER stress and activation of all three UPR pathways in the hypothalamus. Although ObR expression was unchanged, signal transducer and activator of transcription 3 (STAT3) phosphorylation was decreased, suggesting reduced ObR signaling. Unchanged suppressor of cytokine signaling-3 (SOCS3) expression and increases in protein-tyrosine phosphatase 1B (PTP1B) expression and activity emerged with SF, along with reduced p-STAT3 responses to exogenous leptin. SF-induced effects were reversed following TUDCA treatment and were absent in CHOP −/+ mice. Conclusions: Sleep fragmentation (SF) induces hyperphagic behaviors and reduced leptin signaling in hypothalamus that are mediated by activation of endoplasmic reticulum (ER) stress, and ultimately lead to increased PTP1B activity. ER stress pathways are therefore potentially implicated in SF-induced weight gain and metabolic dysfunction, and may represent a viable therapeutic target. Citation: Hakim F, Wang Y, Carreras A, Hirotsu C, Zhang J, Peris E, Gozal D. Chronic sleep

  1. Irregular Periods

    MedlinePlus

    ... number of days after the last one. The Menstrual Cycle Most girls get their first period between the ... to skip periods or to have an irregular menstrual cycle. Illness, rapid weight change, or stress can also ...

  2. Variations in the pre-ejection period induced by deep breathing do not predict the hemodynamic response to early haemorrhage in healthy volunteers.

    PubMed

    Vistisen, Simon Tilma; Juhl-Olsen, Peter; Frederiksen, Christian Alcaraz; Kirkegaard, Hans

    2014-06-01

    Monitoring that can predict fluid responsiveness is an unsettled matter for spontaneously breathing patients. Mechanical ventilation induces cyclic variations in blood pressure, e.g. pulse pressure variation, whose magnitude predicts fluid responsiveness in mechanically ventilated patients. In this study, we hypothesised that a deep breathing manoeuvre with its effect on heart rate variability (HRV) could induce similar cyclic variations in blood pressure in spontaneously breathing healthy subjects and that the magnitude of these variations could predict the hemodynamic response to controlled haemorrhage. 37 blood donors were instructed to perform two simple deep breathing manoeuvres prior to blood donation; one manoeuvre with a respiratory cycle every 10 s (0.1 Hz) and one every 6 s (0.167 Hz). The variation in the pre-ejection period (∆PEP) was captured with the electrocardiographic and plethysmographic curves, while the hemodynamic response to haemorrhage was estimated with the cardiac output change assessed with ultrasonography. Respiratory HRV was estimated with root mean square of successive differences (RMSSD). Deep breathing induced cyclic changes in ∆PEP magnitude was significantly correlated to RMSSD (p < 0.005). ∆PEP indexed to RMSSD increased significantly following haemorrhage at the 0.167 Hz respiratory frequency (p = 0.01). At none of the respiratory manoeuvres was ∆PEP nor ∆PEP/RMSSD prior to haemorrhage correlated to changes in cardiac output following haemorrhage. Deep breathing induces cyclic changes in blood pressure that are strongly dependent on HRV. These blood pressure variations do, however, not predict the cardiac output response to controlled haemorrhage.

  3. Chronic sleep fragmentation during the sleep period induces hypothalamic endoplasmic reticulum stress and PTP1b-mediated leptin resistance in male mice.

    PubMed

    Hakim, Fahed; Wang, Yang; Carreras, Alba; Hirotsu, Camila; Zhang, Jing; Peris, Eduard; Gozal, David

    2015-01-01

    Sleep fragmentation (SF) is highly prevalent and may constitute an important contributing factor to excessive weight gain and the metabolic syndrome. Increased endoplasmic reticulum (ER) stress and activation of the unfolded protein response (UPR) leading to the attenuation of leptin receptor signaling in the hypothalamus leads to obesity and metabolic dysfunction. Mice were exposed to SF and sleep control (SC) for varying periods of time during which ingestive behaviors were monitored. UPR pathways and leptin receptor signaling were assessed in hypothalami. To further examine the mechanistic role of ER stress, changes in leptin receptor (ObR) signaling were also examined in wild-type mice treated with the ER chaperone tauroursodeoxycholic acid (TUDCA), as well as in CHOP-/+ transgenic mice. Fragmented sleep in male mice induced increased food intake starting day 3 and thereafter, which was preceded by increases in ER stress and activation of all three UPR pathways in the hypothalamus. Although ObR expression was unchanged, signal transducer and activator of transcription 3 (STAT3) phosphorylation was decreased, suggesting reduced ObR signaling. Unchanged suppressor of cytokine signaling-3 (SOCS3) expression and increases in protein-tyrosine phosphatase 1B (PTP1B) expression and activity emerged with SF, along with reduced p-STAT3 responses to exogenous leptin. SF-induced effects were reversed following TUDCA treatment and were absent in CHOP -/+ mice. SF induces hyperphagic behaviors and reduced leptin signaling in hypothalamus that are mediated by activation of ER stress, and ultimately lead to increased PTP1B activity. ER stress pathways are therefore potentially implicated in SF-induced weight gain and metabolic dysfunction, and may represent a viable therapeutic target. © 2014 Associated Professional Sleep Societies, LLC.

  4. Pharmacologically induced/exacerbated restless legs syndrome, periodic limb movements of sleep, and REM behavior disorder/REM sleep without atonia: literature review, qualitative scoring, and comparative analysis.

    PubMed

    Hoque, Romy; Chesson, Andrew L

    2010-02-15

    Pharmacologically induced/exacerbated restless legs syndrome (RLS), periodic limb movements in sleep (PLMS), and REM behavior disorder/REM sleep without atonia (RSWA) are increasingly recognized in clinical sleep medicine. A scoring system to evaluate the literature was created and implemented. The aim was to identify the evidence with the least amount of confound, allowing for more reliable determinations of iatrogenic etiology. Points were provided for the following criteria: manuscript type (abstract, peer-reviewed paper); population size studied (large retrospective study, small case series, case report); explicitly stated dosage timing; identification of peak symptoms related to time of medication administration (i.e., medication was ingested in the evening or at bedtime); initiation of a treatment plan; symptoms subsided or ceased with decreased dosage or drug discontinuation (for RLS articles only); negative personal history for RLS prior to use of the medication; exclusion of tobacco/alcohol/excessive caffeine use; exclusion of sleep disordered breathing by polysomnography (PSG); and PSG documentation of presence or absence of PLMS. For RLS and PLMS articles were also given points for the following criteria: each 2003 National Institutes of Health (NIH) RLS criteria met; exclusion of low serum ferritin; and exclusion of peripheral neuropathy by neurological examination. Thirty-two articles on drug-induced RLS, 6 articles on drug-induced PLMS, and 15 articles on drug-induced RBD/ RSWA were analyzed. Based on scores < or = 10 and trials of medication reduction/cessation, the strongest evidence available for drug induced RLS are for the following drugs: escitalopram; fluoxetine; L-dopa/carbidopa and pergolide; L-thyroxine; mianserin; mirtazapine; olanzapine; and tramadol. Since none of the PLMS articles assessed PLMI in trials of medication reduction/cessation, the strongest evidence based on scores > or = 10 are for the following drugs: bupropion, citalopram

  5. Laser-induced-damage threshold of periodically poled lithium niobate for 1030 nm femtosecond laser pulses at 100 kHz and 75 MHz

    NASA Astrophysics Data System (ADS)

    Pipinyté, I.; Grigonis, R.; Stankevičiuté, K.; Kičas, S.; Drazdys, R.; Eckardt, R. C.; Sirutkaitis, V.

    2013-07-01

    We report laser-induced damage threshold (LIDT) measurements of periodically poled lithium niobate (PPLN) and magnesium-oxide-doped PPLN (MgO:PPLN) in the femtosecond pulse duration regime at 1030 nm with 100 kHz and 75 MHz repetition rate. PPLN and MgO:PPLN crystals with broadband Nb2O5/SiO2 AR coatings for 1.4 - 1.8 um spectral range were used. S-on-1 test for LIDT measurements were performed. S was equal to 106 and 4.56*1010 pulses for 100 kHz CPA laser system and 75 MHz oscillator, respectively. Evaluated LIDT was 20 mJ/cm2 for 290 fs pulses at 100 kHz repetition rate and 0.63 mJ/cm2 for 105 fs pulses at 76 MHz repetition rate.

  6. E74-like factor inhibition induces reacquisition of hormone sensitiveness decreasing period circadian protein homolog 1 expression in prostate cancer cells☆

    PubMed Central

    Koyama, Kohei; Takahara, Kiyoshi; Inamoto, Teruo; Ibuki, Naokazu; Minami, Koichiro; Uehara, Hirofumi; Komura, Kazumasa; Nishida, Takeshi; Sakamoto, Takeshi; Hirano, Hajime; Nomi, Hayahito; Kiyama, Satoshi; Azuma, Haruhito

    2015-01-01

    Purpose Initiating as an androgen-dependent adenocarcinoma, prostate cancer (PCa) gradually progresses to a castrate-resistant disease following androgen deprivation therapy with a propensity to metastasize. Methods In order to resolve the mechanism of castrate-resistant PCa, we performed a cDNA-microarray assay of two PCa cell lines, LNCaP (androgen dependent) and C4-2 (androgen independent). Among them, we focused on a novel Ets transcription factor, E74-like factor 5 (ELF5), the expression level of which was extremely high in C4-2 in comparison with LNCaP both in the microarray analysis and real-time polymerase chain reaction analysis, and investigated the biological role in acquisition of androgen-refractory PCa growth. Results Western blot analysis and morphological analysis using confocal immunofluorescence microscopy demonstrated that ELF5 was expressed mainly in cytosol both in LNCaP and C4-2. Inhibition of ELF5 expression using ELF5-small interfering RNA in C4-2 induced decreased expression of androgen receptor corepressor, period circadian protein homolog 1, and MTT assay of C4-2 after ELF5 small interfering RNA transfection showed the same cell growth pattern of LNCaP. Conclusions Our in vitro experiments of cell growth and microarray analysis have demonstrated for the first time that decreased expression of period circadian protein homolog 1 due to ELF5 inhibition may induce the possibility of reacquisition of hormone sensitiveness of PCa cells. We suggest that ELF5 could be a novel potential target for the treatment of hormone-refractory PCa patients. PMID:26288799

  7. Formaldehyde and co-exposure with benzene induce compensation of bone marrow and hematopoietic stem/progenitor cells in BALB/c mice during post-exposure period.

    PubMed

    Wei, Chenxi; Chen, Mouying; You, Huihui; Qiu, Feng; Wen, Huaxiao; Yuan, Junlin; Xiang, Shuanglin; Yang, Xu

    2017-06-01

    Formaldehyde (FA) is a human leukemogen. Since there is a latency period between initial FA exposure and the development of leukemia, the subsequent impact of FA on hematopoietic stem or progenitor cells (HSCs/HPCs) in post-exposure stage is crucial for a deep understanding of FA-induced hematotoxicity. BALB/c mice were exposed to 3mg/m(3) FA for 2weeks, mimicking occupational exposure, and were monitored for another 7days post-exposure. Meanwhile, we included benzene (BZ) as a positive control, separately and together with FA because co-exposure occurs frequently. After 7-day recovery, colonies of progenitors for CFU-GM and BFU-E, and nucleated bone marrow cells in FA-exposed mice were comparable to controls, although they were significantly reduced during exposure. Levels of reactive oxygen species (ROS) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in CFU-GM and BFU-E from FA-exposed mice were higher than controls, although the increase in 8-OHdG was not significant. Granulocyte-macrophage colony stimulating factor (GM-CSF) level in the FA group was lower than controls, but the expression level for the receptor was not upregulated. It suggests that HSCs/HPCs in FA-exposed mice respond to a small amount of GM-CSF and proliferate rapidly, which may cause a possible risk of expansion of abnormal stem/progenitor cell clones. FA co-exposure with BZ was more potent for promoting CFU-GM formation and inducing ROS in BFU-E and 8-OHdG in CFU-GM during the post-exposure period. The compensation of myeloid progenitors with elevated ROS and 8-OHdG may lead to a risk of transforming normal HSCs/HPCs to leukemic stem/progenitor cells. Thus, co-exposure may pose a greater leukemia risk. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Stress during a Critical Postnatal Period Induces Region-Specific Structural Abnormalities and Dysfunction of the Prefrontal Cortex via CRF1

    PubMed Central

    Yang, Xiao-Dun; Liao, Xue-Mei; Uribe-Mariño, Andrés; Liu, Rui; Xie, Xiao-Meng; Jia, Jiao; Su, Yun-Ai; Li, Ji-Tao; Schmidt, Mathias V; Wang, Xiao-Dong; Si, Tian-Mei

    2015-01-01

    During the early postnatal period, environmental influences play a pivotal role in shaping the development of the neocortex, including the prefrontal cortex (PFC) that is crucial for working memory and goal-directed actions. Exposure to stressful experiences during this critical period may disrupt the development of PFC pyramidal neurons and impair the wiring and function of related neural circuits. However, the molecular mechanisms of the impact of early-life stress on PFC development and function are not well understood. In this study, we found that repeated stress exposure during the first postnatal week hampered dendritic development in layers II/III and V pyramidal neurons in the dorsal agranular cingulate cortex (ACd) and prelimbic cortex (PL) of neonatal mice. The deleterious effects of early postnatal stress on structural plasticity persisted to adulthood only in ACd layer V pyramidal neurons. Most importantly, concurrent blockade of corticotropin-releasing factor receptor 1 (CRF1) by systemic antalarmin administration (20 μg/g of body weight) during early-life stress exposure prevented stress-induced apical dendritic retraction and spine loss in ACd layer V neurons and impairments in PFC-dependent cognitive tasks. Moreover, the magnitude of dendritic regression, especially the shrinkage of apical branches, of ACd layer V neurons predicted the degree of cognitive deficits in stressed mice. Our data highlight the region-specific effects of early postnatal stress on the structural plasticity of prefrontal pyramidal neurons, and suggest a critical role of CRF1 in modulating early-life stress-induced prefrontal abnormalities. PMID:25403725

  9. Ultrashort pulse laser dicing of thin Si wafers: the influence of laser-induced periodic surface structures on the backside breaking strength

    NASA Astrophysics Data System (ADS)

    Domke, Matthias; Egle, Bernadette; Piredda, Giovanni; Stroj, Sandra; Fasching, Gernot; Bodea, Marius; Schwarz, Elisabeth

    2016-11-01

    High power electronic chips are usually fabricated on about 50 µm thin Si wafers to improve heat dissipation. At these chip thicknesses mechanical dicing becomes challenging. Chippings may occur at the cutting edges, which reduce the mechanical stability of the die. Thermal load changes could then lead to sudden chip failure. Ultrashort pulsed lasers are a promising tool to improve the cutting quality, because thermal side effects can be reduced to a minimum. However, laser-induced periodic surface structures occur at the sidewalls and at the trench bottom during scribing. The goal of this study was to investigate the influence of these periodic structures on the backside breaking strength of the die. An ultrafast laser with a pulse duration of 380 fs and a wavelength of 1040 nm was used to cut a wafer into single chips. The pulse energy and the number of scans was varied. The cuts in the wafer were investigated using transmitted light microscopy, the sidewalls of the cut chips were investigated using scanning electron and confocal microscopy, and the breaking strength was evaluated using the 3-point bending test. The results indicated that periodic holes with a distance of about 20-30 µm were formed at the bottom of the trench, if the number of scans was set too low to completely cut the wafer; the wafer was only perforated. Mechanical breaking of the bridges caused 5 µm deep kerfs in the sidewall. These kerfs reduced the breaking strength at the backside of the chip to about 300 MPa. As the number of scans was increased, the bridges were ablated and the wafer was cut completely. Periodic structures were observed on the sidewall; the roughness was below 1 µm. The surface roughness remained on a constant level even when the number of scans was doubled. However, the periodic structures on the sidewall seemed to vanish and the probability to remove local flaws increases with the number of scans. As a consequence, the breaking strength was increased to about

  10. Measurements and Monte Carlo simulations of the spectral variations of the cosmic-ray-induced neutrons at the Pic du Midi over a 2-y period.

    PubMed

    Cheminet, A; Hubert, G; Lacoste, V; Boscher, D

    2014-10-01

    In this paper, a Bonner Sphere Spectrometer extended to high energies (HERMEIS) was employed to measure continuously the cosmic-ray-induced neutron spectra over a long-term period (2 y) at mountain altitude and medium geomagnetic latitude (Pic du Midi de Bigorre in the French Pyrenees, +2885 m, 5.6 GV). The results showed 1-y sinusoidal oscillations in the integrated fluence rates. The amplitude of these oscillations depends on the neutron energetic domain. The fluence rate of thermal neutrons was 53 % higher in August than that in February. Those of epithermal neutrons with energies between 0.4 eV and 0.1 MeV and evaporation neutrons (from 0.1 to 20 MeV) were ∼25 % higher in the summer than those in the winter. Finally, the cascade neutron fluence rate (>20 MeV) remained quite the same (<10 % variation). To understand the effects of local and seasonal changes in the measurement environment, GEANT4 simulations were performed. The nature of rock and thickness of the snow cover during the winter period (given by meteorological data) were investigated. A reasonable agreement between experiments and calculations was found.

  11. The influences of surface plasmons and thermal effects on femtosecond laser-induced subwavelength periodic ripples on Au film by pump-probe imaging

    NASA Astrophysics Data System (ADS)

    Zhou, Kan; Jia, Xin; Jia, Tianqing; Cheng, Ke; Cao, Kaiqiang; Zhang, Shian; Feng, Donghai; Sun, Zhenrong

    2017-03-01

    In this paper, the influences of surface plasmons and thermal effects on the formation of subwavelength periodic ripples on Au films irradiated by 800 nm femtosecond laser pulses were studied by collinear pump-probe imaging. The spatial and temporal resolutions of the experiment were 300 nm and 1 ps, respectively. No periodic ripples were observed on the Au film during ablation by the first pump pulse, but during ablation by the second pump pulse the appearance of transient ripples was evident from a delay time of hundreds of picoseconds to several nanoseconds. These ripples, however, were not retained after solidification. When the sample was immersed in water during ablation, however, the ripples were retained. It is proposed that, during the second laser pulse irradiation, the surface defects produced by the first pulse induced surface plasmon polaritons on the Au film, which caused a modulated energy deposition and the formation of transient ripples. The weak electron-phonon coupling and significant residual heat erase these ripples after the molten surface was solidified.

  12. Fabrication and characterization of a non-zero dispersion-shifted mechanically-induced long-period grating for optical fiber sensing

    NASA Astrophysics Data System (ADS)

    Gallegos-Arellano, E.; Mata Chávez, R. I.; Huerta-Mascotte, E.; Estudillo-Ayala, J. M.; Guzmán-Chávez, A. D.; Vargas-Rodriguez, E.; Sierra-Hernández, J. M.; Rojas-Laguna, R.; Guryev, I.

    2015-08-01

    We present the fabrication and characterization of a mechanically induced long period grating (MLPG) using a grating period of 400 μm and 1m of NZ-DSF. Pressure is gradually applied up to 120 Lb at different angles like 0, 30, 45 and 60 degrees. An attenuation band is observed centered at a wavelength around 1064nm using a fiber position of 30 degrees with respect to the gratinǵs metal plate and a maximum pressure of 145 Lb. The loss band presents a maximum depth of 22dB and a bandwidth of approximately 10nm. Torsion and curvature characterizations did not change the output spectrum of the optical grating. However, temperature characterization depicted a small shifting which could be insignificant for some applications. Still, there is 16dB attenuation as temperature increases in a range from room temperature up to 450°C. These preliminary studies show that this 1064 nm centered wavelength MILPG might be used in a low linear dynamic range with temperature (75-300)°C as a temperature sensor.

  13. Implications of transient changes of optical and surface properties of solids during femtosecond laser pulse irradiation to the formation of laser-induced periodic surface structures

    NASA Astrophysics Data System (ADS)

    Bonse, J.; Rosenfeld, A.; Krüger, J.

    2011-04-01

    The formation of laser-induced periodic surface structures (LIPSS) upon irradiation of silicon wafer surfaces by linearly polarized Ti:sapphire femtosecond laser pulses (pulse duration 130 fs, central wavelength 800 nm) is studied experimentally and theoretically. In the experiments, so-called low-spatial frequency LIPSS (LSFL) were found with periods smaller than the laser wavelength and an orientation perpendicular to the polarization. The experimental results are analyzed by means of a new theoretical approach, which combines the widely accepted LIPSS theory of Sipe et al. with a Drude model, in order to account for transient (intra-pulse) changes of the optical properties of the irradiated materials. It is found that the LSFL formation is caused by the excitation of surface plasmon polaritons, SPPs, once the initially semiconducting material turns to a metallic state upon formation of a dense free-electron-plasma in the material and the subsequent interference between its electrical field with that of the incident laser beam resulting in a spatially modulated energy deposition at the surface. Moreover, the influence of the laser-excited carrier density and the role of the feedback upon the multi-pulse irradiation and its relation to the excitation of SPP in a grating-like surface structure is discussed.

  14. Highly Ordered Periodic Au/TiO₂ Hetero-Nanostructures for Plasmon-Induced Enhancement of the Activity and Stability for Ethanol Electro-oxidation.

    PubMed

    Jin, Zhao; Wang, Qiyu; Zheng, Weitao; Cui, Xiaoqiang

    2016-03-02

    The catalytic electro-oxidation of ethanol is the essential technique for direct alcohol fuel cells (DAFCs) in the area of alternative energy for the ability of converting the chemical energy of alcohol into the electric energy directly. Developing highly efficient and stable electrode materials with antipoisoning ability for ethanol electro-oxidation remains a challenge. A highly ordered periodic Au-nanoparticle (NP)-decorated bilayer TiO2 nanotube (BTNT) heteronanostructure was fabricated by a two-step anodic oxidation of Ti foil and the subsequent photoreduction of HAuCl4. The plasmon-induced charge separation on the heterointerface of Au/TiO2 electrode enhances the electrocatalytic activity and stability for the ethanol oxidation under visible light irradiation. The highly ordered periodic heterostructure on the electrode surface enhanced the light harvesting and led to the greater performance of ethanol electro-oxidation under irradiation compared with the ordinary Au NPs-decorated monolayer TiO2 nanotube (MTNT). This novel Au/TiO2 electrode also performed a self-cleaning property under visible light attributed to the enhanced electro-oxidation of the adsorbed intermediates. This light-driven enhancement of the electrochemical performances provides a development strategy for the design and construction of DAFCs.

  15. Beam-induced and cosmic-ray backgrounds observed in the ATLAS detector during the LHC 2012 proton-proton running period

    SciTech Connect

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A.; Buehrer, F.; Bugge, M. K.; Bulekov, O.; Bullock, D.; Burckhart, H.; Burdin, S.; Burgard, C. D.; Burghgrave, B.; Burka, K.; Burke, S.; Burmeister, I.; Busato, E.; Büscher, D.; Büscher, V.; Bussey, P.; Butler, J. M.; Butt, A. I.; Buttar, C. M.; Butterworth, J. M.; Butti, P.; Buttinger, W.; Buzatu, A.; Buzykaev, A. R.; Urbán, S. Cabrera; Caforio, D.; Cairo, V. M.; Cakir, O.; Calace, N.; Calafiura, P.; Calandri, A.; Calderini, G.; Calfayan, P.; Caloba, L. P.; Calvet, D.; Calvet, S.; Calvet, T. P.; Toro, R. Camacho; Camarda, S.; Camarri, P.; Cameron, D.; Armadans, R. Caminal; Camincher, C.; Campana, S.; Campanelli, M.; Campoverde, A.; Canale, V.; Canepa, A.; Bret, M. Cano; Cantero, J.; Cantrill, R.; Cao, T.; Garrido, M. D. M. Capeans; Caprini, I.; Caprini, M.; Capua, M.; Caputo, R.; Carbone, R. M.; Cardarelli, R.; Cardillo, F.; Carli, T.; Carlino, G.; Carminati, L.; Caron, S.; Carquin, E.; Carrillo-Montoya, G. D.; Carter, J. R.; Carvalho, J.; Casadei, D.; Casado, M. P.; Casolino, M.; Casper, D. W.; Castaneda-Miranda, E.; Castelli, A.; Gimenez, V. Castillo; Castro, N. F.; Catinaccio, A.; Catmore, J. R.; Cattai, A.; Caudron, J.; Cavaliere, V.; Cavallaro, E.; Cavalli, D.; Cavalli-Sforza, M.; Cavasinni, V.; Ceradini, F.; Alberich, L. Cerda; Cerio, B. C.; Cerqueira, A. S.; Cerri, A.; Cerrito, L.; Cerutti, F.; Cerv, M.; Cervelli, A.; Cetin, S. A.; Chafaq, A.; Chakraborty, D.; Chalupkova, I.; Chan, S. K.; Chan, Y. L.; Chang, P.; Chapman, J. D.; Charlton, D. G.; Chatterjee, A.; Chau, C. C.; Barajas, C. A. Chavez; Che, S.; Cheatham, S.; Chegwidden, A.; Chekanov, S.; Chekulaev, S. V.; Chelkov, G. A.; Chelstowska, M. A.; Chen, C.; Chen, H.; Chen, K.; Chen, S.; Chen, S.; Chen, X.; Chen, Y.; Cheng, H. C.; Cheng, H. J.; Cheng, Y.; Cheplakov, A.; Cheremushkina, E.; Moursli, R. Cherkaoui El; Chernyatin, V.; Cheu, E.; Chevalier, L.; Chiarella, V.; Chiarelli, G.; Chiodini, G.; Chisholm, A. S.; Chitan, A.; Chizhov, M. V.; Choi, K.; Chomont, A. R.; Chouridou, S.; Chow, B. K. B.; Christodoulou, V.; Chromek-Burckhart, D.; Chudoba, J.; Chuinard, A. J.; Chwastowski, J. J.; Chytka, L.; Ciapetti, G.; Ciftci, A. K.; Cinca, D.; Cindro, V.; Cioara, I. A.; Ciocio, A.; Cirotto, F.; Citron, Z. H.; Ciubancan, M.; Clark, A.; Clark, B. L.; Clark, M. R.; Clark, P. J.; Clarke, R. N.; Clement, C.; Coadou, Y.; Cobal, M.; Coccaro, A.; Cochran, J.; Coffey, L.; Colasurdo, L.; Cole, B.; Cole, S.; Colijn, A. P.; Collot, J.; Colombo, T.; Compostella, G.; Muiño, P. Conde; Coniavitis, E.; Connell, S. H.; Connelly, I. A.; Consorti, V.; Constantinescu, S.; Conta, C.; Conti, G.; Conventi, F.; Cooke, M.; Cooper, B. D.; Cooper-Sarkar, A. M.; Cornelissen, T.; Corradi, M.; Corriveau, F.; Corso-Radu, A.; Cortes-Gonzalez, A.; Cortiana, G.; Costa, G.; Costa, M. J.; Costanzo, D.; Cottin, G.; Cowan, G.; Cox, B. E.; Cranmer, K.; Crawley, S. J.; Cree, G.; Crépé-Renaudin, S.; Crescioli, F.; Cribbs, W. A.; Ortuzar, M. Crispin; Cristinziani, M.; Croft, V.; Crosetti, G.; Donszelmann, T. Cuhadar; Cummings, J.; Curatolo, M.; Cúth, J.; Cuthbert, C.; Czirr, H.; Czodrowski, P.; D'Auria, S.; D'Onofrio, M.; Sousa, M. J. Da Cunha Sargedas De; Via, C. Da; Dabrowski, W.; Dai, T.; Dale, O.; Dallaire, F.; Dallapiccola, C.; Dam, M.; Dandoy, J. R.; Dang, N. P.; Daniells, A. C.; Dann, N. S.; Danninger, M.; Hoffmann, M. Dano; Dao, V.; Darbo, G.; Darmora, S.; Dassoulas, J.; Dattagupta, A.; Davey, W.; David, C.; Davidek, T.; Davies, M.; Davison, P.; Davygora, Y.; Dawe, E.; Dawson, I.; Daya-Ishmukhametova, R. K.; De, K.; de Asmundis, R.; Benedetti, A. De; Castro, S. De; Cecco, S. De; Groot, N. De; de Jong, P.; Torre, H. De la; Lorenzi, F. De; Pedis, D. De; Salvo, A. De; Sanctis, U. De; Santo, A. De; Regie, J. B. De Vivie De; Dearnaley, W. J.; Debbe, R.; Debenedetti, C.; Dedovich, D. V.; Deigaard, I.; Peso, J. Del; Prete, T. Del; Delgove, D.; Deliot, F.; Delitzsch, C. M.; Deliyergiyev, M.; Dell'Acqua, A.; Dell'Asta, L.; Dell'Orso, M.; Pietra, M. Della; Volpe, D. della; Delmastro, M.; Delsart, P. A.; Deluca, C.; DeMarco, D. A.; Demers, S.; Demichev, M.; Demilly, A.; Denisov, S. P.; Denysiuk, D.; Derendarz, D.; Derkaoui, J. E.; Derue, F.; Dervan, P.; Desch, K.; Deterre, C.; Dette, K.; Deviveiros, P. O.; Dewhurst, A.; Dhaliwal, S.; Ciaccio, A. Di; Ciaccio, L. Di; Clemente, W. K. Di; Donato, C. Di; Girolamo, A. Di; Girolamo, B. Di; Micco, B. Di; Nardo, R. Di; Simone, A. Di; Sipio, R. Di; Valentino, D. Di; Diaconu, C.; Diamond, M.; Dias, F. A.; Diaz, M. A.; Diehl, E. B.; Dietrich, J.; Diglio, S.; Dimitrievska, A.; Dingfelder, J.; Dita, P.; Dita, S.; Dittus, F.; Djama, F.; Djobava, T.; Djuvsland, J. I.; Vale, M. A. B. do; Dobos, D.; Dobre, M.; Doglioni, C.; Dohmae, T.; Dolejsi, J.; Dolezal, Z.; Dolgoshein, B. A.; Donadelli, M.; Donati, S.; Dondero, P.; Donini, J.; Dopke, J.; Doria, A.; Dova, M. T.; Doyle, A. T.; Drechsler, E.; Dris, M.; Du, Y.; Duarte-Campderros, J.; Duchovni, E.; Duckeck, G.; Ducu, O. A.; Duda, D.; Dudarev, A.; Duflot, L.; Duguid, L.; Dührssen, M.; Dunford, M.; Yildiz, H. Duran; Düren, M.; Durglishvili, A.; Duschinger, D.; Dutta, B.; Dyndal, M.; Eckardt, C.; Ecker, K. M.; Edgar, R. C.; Edson, W.; Edwards, N. C.; Eifert, T.; Eigen, G.; Einsweiler, K.; Ekelof, T.; Kacimi, M. El; Ellajosyula, V.; Ellert, M.; Elles, S.; Ellinghaus, F.; Elliot, A. A.; Ellis, N.; Elmsheuser, J.; Elsing, M.; Emeliyanov, D.; Enari, Y.; Endner, O. C.; Endo, M.; Ennis, J. S.; Erdmann, J.; Ereditato, A.; Ernis, G.; Ernst, J.; Ernst, M.; Errede, S.; Ertel, E.; Escalier, M.; Esch, H.; Escobar, C.; Esposito, B.; Etienvre, A. I.; Etzion, E.; Evans, H.; Ezhilov, A.; Fabbri, F.; Fabbri, L.; Facini, G.; Fakhrutdinov, R. M.; Falciano, S.; Falla, R. J.; Faltova, J.; Fang, Y.; Fanti, M.; Farbin, A.; Farilla, A.; Farina, C.; Farooque, T.; Farrell, S.; Farrington, S. 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D.; Papageorgiou, K.; Paramonov, A.; Hernandez, D. Paredes; Parker, A. J.; Parker, M. A.; Parker, K. A.; Parodi, F.; Parsons, J. A.; Parzefall, U.; Pascuzzi, V. R.; Pasqualucci, E.; Passaggio, S.; Pastore, F.; Pastore, Fr.; Pásztor, G.; Pataraia, S.; Patel, N. D.; Pater, J. R.; Pauly, T.; Pearce, J.; Pearson, B.; Pedersen, L. E.; Pedersen, M.; Lopez, S. Pedraza; Pedro, R.; Peleganchuk, S. V.; Pelikan, D.; Penc, O.; Peng, C.; Peng, H.; Penwell, J.; Peralva, B. S.; Perego, M. M.; Perepelitsa, D. V.; Codina, E. Perez; Perini, L.; Pernegger, H.; Perrella, S.; Peschke, R.; Peshekhonov, V. D.; Peters, K.; Peters, R. F. Y.; Petersen, B. A.; Petersen, T. C.; Petit, E.; Petridis, A.; Petridou, C.; Petroff, P.; Petrolo, E.; Petrov, M.; Petrucci, F.; Pettersson, N. E.; Peyaud, A.; Pezoa, R.; Phillips, P. W.; Piacquadio, G.; Pianori, E.; Picazio, A.; Piccaro, E.; Piccinini, M.; Pickering, M. A.; Piegaia, R.; Pilcher, J. E.; Pilkington, A. D.; Pin, A. W. J.; Pina, J.; Pinamonti, M.; Pinfold, J. L.; Pingel, A.; Pires, S.; Pirumov, H.; Pitt, M.; Plazak, L.; Pleier, M. -A.; Pleskot, V.; Plotnikova, E.; Plucinski, P.; Pluth, D.; Poettgen, R.; Poggioli, L.; Pohl, D.; Polesello, G.; Poley, A.; Policicchio, A.; Polifka, R.; Polini, A.; Pollard, C. S.; Polychronakos, V.; Pommès, K.; Pontecorvo, L.; Pope, B. G.; Popeneciu, G. A.; Popovic, D. S.; Poppleton, A.; Pospisil, S.; Potamianos, K.; Potrap, I. N.; Potter, C. J.; Potter, C. T.; Poulard, G.; Poveda, J.; Pozdnyakov, V.; Astigarraga, M. E. Pozo; Pralavorio, P.; Pranko, A.; Prell, S.; Price, D.; Price, L. E.; Primavera, M.; Prince, S.; Proissl, M.; Prokofiev, K.; Prokoshin, F.; Protopopescu, S.; Proudfoot, J.; Przybycien, M.; Puddu, D.; Puldon, D.; Purohit, M.; Puzo, P.; Qian, J.; Qin, G.; Qin, Y.; Quadt, A.; Quayle, W. B.; Queitsch-Maitland, M.; Quilty, D.; Raddum, S.; Radeka, V.; Radescu, V.; Radhakrishnan, S. K.; Radloff, P.; Rados, P.; Ragusa, F.; Rahal, G.; Raine, J. A.; Rajagopalan, S.; Rammensee, M.; Rangel-Smith, C.; Ratti, M. G.

    2016-05-20

    This paper discusses various observations on beam-induced and cosmic-ray backgrounds in the ATLAS detector during the LHC 2012 proton-proton run. Building on published results based on 2011 data, the correlations between background and residual pressure of the beam vacuum are revisited. Ghost charge evolution over 2012 and its role for backgrounds are evaluated. New methods to monitor ghost charge with beam-gas rates are presented and observations of LHC abort gap population by ghost charge are discussed in detail. Fake jets from colliding bunches and from ghost charge are analysed with improved methods, showing that ghost charge in individual radio-frequency buckets of the LHC can be resolved. Some results of two short periods of dedicated cosmic-ray background data-taking are shown; in particular cosmic-ray muon induced fake jet rates are compared to Monte Carlo simulations and to the fake jet rates from beam background. A thorough analysis of a particular LHC fill, where abnormally high background was observed, is presented. Correlations between backgrounds and beam intensity losses in special fills with very high β* are studied.

  16. Beam-induced and cosmic-ray backgrounds observed in the ATLAS detector during the LHC 2012 proton-proton running period

    DOE PAGES

    Aad, G.; Abbott, B.; Abdallah, J.; ...

    2016-05-20

    This paper discusses various observations on beam-induced and cosmic-ray backgrounds in the ATLAS detector during the LHC 2012 proton-proton run. Building on published results based on 2011 data, the correlations between background and residual pressure of the beam vacuum are revisited. Ghost charge evolution over 2012 and its role for backgrounds are evaluated. New methods to monitor ghost charge with beam-gas rates are presented and observations of LHC abort gap population by ghost charge are discussed in detail. Fake jets from colliding bunches and from ghost charge are analysed with improved methods, showing that ghost charge in individual radio-frequency bucketsmore » of the LHC can be resolved. Some results of two short periods of dedicated cosmic-ray background data-taking are shown; in particular cosmic-ray muon induced fake jet rates are compared to Monte Carlo simulations and to the fake jet rates from beam background. A thorough analysis of a particular LHC fill, where abnormally high background was observed, is presented. Correlations between backgrounds and beam intensity losses in special fills with very high β* are studied.« less

  17. Infrared-induced variation of the magnetic properties of a magnetoplasmonic film with a 3D sub-micron periodic triangular roof-type antireflection structure.

    PubMed

    Tian, Junlong; Zhang, Wang; Huang, Yiqiao; Liu, Qinglei; Wang, Yuhua; Zhang, Zhijian; Zhang, Di

    2015-01-26

    A carbon-matrix nickel composite magnetoplasmonic film with a 3D sub-micron periodic triangular roof-type antireflection structure (SPTAS) was fabricated via a simple and promising method that combines chemosynthesis with biomimetic techniques. The Troides helena (Linnaeus) forewing (T_FW) was chosen as the biomimetic template. The carbon-matrix Ni wing fabricated via electroless Ni deposition for 6 h (CNMF_6h) exhibits enhanced infrared absorption. Over a wavelength range (888-2500 nm), the enhancement of the infrared absorption of CNMF_6h is up to 1.85 times compared with the T_FW. Furthermore, infrared excitation induces a photothermal effect that results in variation in the magnetic properties of the carbon-matrix Ni wing. The magnetic properties were also confirmed using atomic force microscopy (AFM) and magnetic force microscopy (MFM). The good correlation between the AFM and MFM images demonstrates that the surface of the SPTAS of CNMF_6h exhibits strong magnetic properties. The infrared induced photothermal effect that results in magnetic variation is promising for use in the design of novel magnetoplasmonic films with potential applications in infrared information recording and heat-assisted magnetic recording.

  18. Infrared-induced variation of the magnetic properties of a magnetoplasmonic film with a 3D sub-micron periodic triangular roof-type antireflection structure

    NASA Astrophysics Data System (ADS)

    Tian, Junlong; Zhang, Wang; Huang, Yiqiao; Liu, Qinglei; Wang, Yuhua; Zhang, Zhijian; Zhang, Di

    2015-01-01

    A carbon-matrix nickel composite magnetoplasmonic film with a 3D sub-micron periodic triangular roof-type antireflection structure (SPTAS) was fabricated via a simple and promising method that combines chemosynthesis with biomimetic techniques. The Troides helena (Linnaeus) forewing (T_FW) was chosen as the biomimetic template. The carbon-matrix Ni wing fabricated via electroless Ni deposition for 6 h (CNMF_6h) exhibits enhanced infrared absorption. Over a wavelength range (888-2500 nm), the enhancement of the infrared absorption of CNMF_6h is up to 1.85 times compared with the T_FW. Furthermore, infrared excitation induces a photothermal effect that results in variation in the magnetic properties of the carbon-matrix Ni wing. The magnetic properties were also confirmed using atomic force microscopy (AFM) and magnetic force microscopy (MFM). The good correlation between the AFM and MFM images demonstrates that the surface of the SPTAS of CNMF_6h exhibits strong magnetic properties. The infrared induced photothermal effect that results in magnetic variation is promising for use in the design of novel magnetoplasmonic films with potential applications in infrared information recording and heat-assisted magnetic recording.

  19. Beam-induced and cosmic-ray backgrounds observed in the ATLAS detector during the LHC 2012 proton-proton running period

    NASA Astrophysics Data System (ADS)

    Aad, G.; Abbott, B.; Abdallah, J.; Abdinov, O.; Abeloos, B.; Aben, R.; Abolins, M.; AbouZeid, O. S.; Abraham, N. L.; Abramowicz, H.; Abreu, H.; Abreu, R.; Abulaiti, Y.; Acharya, B. S.; Adamczyk, L.; Adams, D. L.; Adelman, J.; Adomeit, S.; Adye, T.; Affolder, A. A.; Agatonovic-Jovin, T.; Agricola, J.; Aguilar-Saavedra, J. A.; Ahlen, S. P.; Ahmadov, F.; Aielli, G.; Akerstedt, H.; Åkesson, T. P. A.; Akimov, A. V.; Alberghi, G. L.; Albert, J.; Albrand, S.; Alconada Verzini, M. J.; Aleksa, M.; Aleksandrov, I. N.; Alexa, C.; Alexander, G.; Alexopoulos, T.; Alhroob, M.; Aliev, M.; Alimonti, G.; Alison, J.; Alkire, S. P.; Allbrooke, B. M. M.; Allen, B. W.; Allport, P. P.; Aloisio, A.; Alonso, A.; Alonso, F.; Alpigiani, C.; Alvarez Gonzalez, B.; Álvarez Piqueras, D.; Alviggi, M. G.; Amadio, B. T.; Amako, K.; Amaral Coutinho, Y.; Amelung, C.; Amidei, D.; Amor Dos Santos, S. P.; Amorim, A.; Amoroso, S.; Amram, N.; Amundsen, G.; Anastopoulos, C.; Ancu, L. S.; Andari, N.; Andeen, T.; Anders, C. F.; Anders, G.; Anders, J. K.; Anderson, K. J.; Andreazza, A.; Andrei, V.; Angelidakis, S.; Angelozzi, I.; Anger, P.; Angerami, A.; Anghinolfi, F.; Anisenkov, A. V.; Anjos, N.; Annovi, A.; Antonelli, M.; Antonov, A.; Antos, J.; Anulli, F.; Aoki, M.; Aperio Bella, L.; Arabidze, G.; Arai, Y.; Araque, J. P.; Arce, A. T. H.; Arduh, F. A.; Arduini, G.; Arguin, J.-F.; Argyropoulos, S.; Arik, M.; Armbruster, A. J.; Armitage, L. J.; Arnaez, O.; Arnold, H.; Arratia, M.; Arslan, O.; Artamonov, A.; Artoni, G.; Artz, S.; Asai, S.; Asbah, N.; Ashkenazi, A.; Åsman, B.; Asquith, L.; Assamagan, K.; Astalos, R.; Atkinson, M.; Atlay, N. B.; Augsten, K.; Avolio, G.; Axen, B.; Ayoub, M. K.; Azuelos, G.; Baak, M. A.; Baas, A. E.; Baca, M. J.; Bachacou, H.; Bachas, K.; Backes, M.; Backhaus, M.; Bagiacchi, P.; Bagnaia, P.; Bai, Y.; Baines, J. T.; Baker, O. K.; Baldin, E. M.; Balek, P.; Balestri, T.; Balli, F.; Balunas, W. K.; Banas, E.; Banerjee, Sw.; Bannoura, A. A. E.; Barak, L.; Barberio, E. L.; Barberis, D.; Barbero, M.; Barillari, T.; Barklow, T.; Barlow, N.; Barnes, S. L.; Barnett, B. M.; Barnett, R. M.; Barnovska, Z.; Baroncelli, A.; Barone, G.; Barr, A. J.; Barranco Navarro, L.; Barreiro, F.; Barreiro Guimarães da Costa, J.; Bartoldus, R.; Barton, A. E.; Bartos, P.; Basalaev, A.; Bassalat, A.; Basye, A.; Bates, R. L.; Batista, S. J.; Batley, J. R.; Battaglia, M.; Bauce, M.; Bauer, F.; Bawa, H. S.; Beacham, J. B.; Beattie, M. D.; Beau, T.; Beauchemin, P. H.; Bechtle, P.; Beck, H. P.; Becker, K.; Becker, M.; Beckingham, M.; Becot, C.; Beddall, A. J.; Beddall, A.; Bednyakov, V. A.; Bedognetti, M.; Bee, C. P.; Beemster, L. J.; Beermann, T. A.; Begel, M.; Behr, J. K.; Belanger-Champagne, C.; Bell, A. S.; Bella, G.; Bellagamba, L.; Bellerive, A.; Bellomo, M.; Belotskiy, K.; Beltramello, O.; Belyaev, N. L.; Benary, O.; Benchekroun, D.; Bender, M.; Bendtz, K.; Benekos, N.; Benhammou, Y.; Benhar Noccioli, E.; Benitez, J.; Benitez Garcia, J. A.; Benjamin, D. P.; Bensinger, J. R.; Bentvelsen, S.; Beresford, L.; Beretta, M.; Berge, D.; Bergeaas Kuutmann, E.; Berger, N.; Berghaus, F.; Beringer, J.; Berlendis, S.; Bernard, N. R.; Bernius, C.; Bernlochner, F. U.; Berry, T.; Berta, P.; Bertella, C.; Bertoli, G.; Bertolucci, F.; Bertram, I. A.; Bertsche, C.; Bertsche, D.; Besjes, G. J.; Bessidskaia Bylund, O.; Bessner, M.; Besson, N.; Betancourt, C.; Bethke, S.; Bevan, A. J.; Bhimji, W.; Bianchi, R. M.; Bianchini, L.; Bianco, M.; Biebel, O.; Biedermann, D.; Bielski, R.; Biesuz, N. V.; Biglietti, M.; Bilbao De Mendizabal, J.; Bilokon, H.; Bindi, M.; Binet, S.; Bingul, A.; Bini, C.; Biondi, S.; Bjergaard, D. M.; Black, C. W.; Black, J. E.; Black, K. M.; Blackburn, D.; Blair, R. E.; Blanchard, J.-B.; Blanco, J. E.; Blazek, T.; Bloch, I.; Blocker, C.; Blum, W.; Blumenschein, U.; Blunier, S.; Bobbink, G. J.; Bobrovnikov, V. S.; Bocchetta, S. S.; Bocci, A.; Bock, C.; Boehler, M.; Boerner, D.; Bogaerts, J. A.; Bogavac, D.; Bogdanchikov, A. G.; Bohm, C.; Boisvert, V.; Bold, T.; Boldea, V.; Boldyrev, A. S.; Bomben, M.; Bona, M.; Boonekamp, M.; Borisov, A.; Borissov, G.; Bortfeldt, J.; Bortoletto, D.; Bortolotto, V.; Bos, K.; Boscherini, D.; Bosman, M.; Bossio Sola, J. D.; Boudreau, J.; Bouffard, J.; Bouhova-Thacker, E. V.; Boumediene, D.; Bourdarios, C.; Boutle, S. K.; Boveia, A.; Boyd, J.; Boyko, I. R.; Bracinik, J.; Brandt, A.; Brandt, G.; Brandt, O.; Bratzler, U.; Brau, B.; Brau, J. E.; Braun, H. M.; Breaden Madden, W. D.; Brendlinger, K.; Brennan, A. J.; Brenner, L.; Brenner, R.; Bressler, S.; Bristow, T. M.; Britton, D.; Britzger, D.; Brochu, F. M.; Brock, I.; Brock, R.; Brooijmans, G.; Brooks, T.; Brooks, W. K.; Brosamer, J.; Brost, E.; Broughton, J. H.; Bruce, R.; Bruckman de Renstrom, P. A.; Bruncko, D.; Bruneliere, R.; Bruni, A.; Bruni, G.; Brunt, BH; Bruschi, M.; Bruscino, N.; Bryant, P.; Bryngemark, L.; Buanes, T.; Buat, Q.; Buchholz, P.; Buckley, A. G.; Budagov, I. 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R.; Chouridou, S.; Chow, B. K. B.; Christodoulou, V.; Chromek-Burckhart, D.; Chudoba, J.; Chuinard, A. J.; Chwastowski, J. J.; Chytka, L.; Ciapetti, G.; Ciftci, A. K.; Cinca, D.; Cindro, V.; Cioara, I. A.; Ciocio, A.; Cirotto, F.; Citron, Z. H.; Ciubancan, M.; Clark, A.; Clark, B. L.; Clark, M. R.; Clark, P. J.; Clarke, R. N.; Clement, C.; Coadou, Y.; Cobal, M.; Coccaro, A.; Cochran, J.; Coffey, L.; Colasurdo, L.; Cole, B.; Cole, S.; Colijn, A. P.; Collot, J.; Colombo, T.; Compostella, G.; Conde Muiño, P.; Coniavitis, E.; Connell, S. H.; Connelly, I. A.; Consorti, V.; Constantinescu, S.; Conta, C.; Conti, G.; Conventi, F.; Cooke, M.; Cooper, B. D.; Cooper-Sarkar, A. M.; Cornelissen, T.; Corradi, M.; Corriveau, F.; Corso-Radu, A.; Cortes-Gonzalez, A.; Cortiana, G.; Costa, G.; Costa, M. J.; Costanzo, D.; Cottin, G.; Cowan, G.; Cox, B. E.; Cranmer, K.; Crawley, S. J.; Cree, G.; Crépé-Renaudin, S.; Crescioli, F.; Cribbs, W. A.; Crispin Ortuzar, M.; Cristinziani, M.; Croft, V.; Crosetti, G.; Cuhadar Donszelmann, T.; Cummings, J.; Curatolo, M.; Cúth, J.; Cuthbert, C.; Czirr, H.; Czodrowski, P.; D'Auria, S.; D'Onofrio, M.; Da Cunha Sargedas De Sousa, M. J.; Da Via, C.; Dabrowski, W.; Dai, T.; Dale, O.; Dallaire, F.; Dallapiccola, C.; Dam, M.; Dandoy, J. R.; Dang, N. P.; Daniells, A. C.; Dann, N. S.; Danninger, M.; Dano Hoffmann, M.; Dao, V.; Darbo, G.; Darmora, S.; Dassoulas, J.; Dattagupta, A.; Davey, W.; David, C.; Davidek, T.; Davies, M.; Davison, P.; Davygora, Y.; Dawe, E.; Dawson, I.; Daya-Ishmukhametova, R. K.; De, K.; de Asmundis, R.; De Benedetti, A.; De Castro, S.; De Cecco, S.; De Groot, N.; de Jong, P.; De la Torre, H.; De Lorenzi, F.; De Pedis, D.; De Salvo, A.; De Sanctis, U.; De Santo, A.; De Vivie De Regie, J. B.; Dearnaley, W. J.; Debbe, R.; Debenedetti, C.; Dedovich, D. V.; Deigaard, I.; Del Peso, J.; Del Prete, T.; Delgove, D.; Deliot, F.; Delitzsch, C. M.; Deliyergiyev, M.; Dell'Acqua, A.; Dell'Asta, L.; Dell'Orso, M.; Della Pietra, M.; della Volpe, D.; Delmastro, M.; Delsart, P. A.; Deluca, C.; DeMarco, D. A.; Demers, S.; Demichev, M.; Demilly, A.; Denisov, S. P.; Denysiuk, D.; Derendarz, D.; Derkaoui, J. E.; Derue, F.; Dervan, P.; Desch, K.; Deterre, C.; Dette, K.; Deviveiros, P. O.; Dewhurst, A.; Dhaliwal, S.; Di Ciaccio, A.; Di Ciaccio, L.; Di Clemente, W. K.; Di Donato, C.; Di Girolamo, A.; Di Girolamo, B.; Di Micco, B.; Di Nardo, R.; Di Simone, A.; Di Sipio, R.; Di Valentino, D.; Diaconu, C.; Diamond, M.; Dias, F. A.; Diaz, M. A.; Diehl, E. B.; Dietrich, J.; Diglio, S.; Dimitrievska, A.; Dingfelder, J.; Dita, P.; Dita, S.; Dittus, F.; Djama, F.; Djobava, T.; Djuvsland, J. I.; do Vale, M. A. B.; Dobos, D.; Dobre, M.; Doglioni, C.; Dohmae, T.; Dolejsi, J.; Dolezal, Z.; Dolgoshein, B. A.; Donadelli, M.; Donati, S.; Dondero, P.; Donini, J.; Dopke, J.; Doria, A.; Dova, M. T.; Doyle, A. T.; Drechsler, E.; Dris, M.; Du, Y.; Duarte-Campderros, J.; Duchovni, E.; Duckeck, G.; Ducu, O. A.; Duda, D.; Dudarev, A.; Duflot, L.; Duguid, L.; Dührssen, M.; Dunford, M.; Duran Yildiz, H.; Düren, M.; Durglishvili, A.; Duschinger, D.; Dutta, B.; Dyndal, M.; Eckardt, C.; Ecker, K. M.; Edgar, R. C.; Edson, W.; Edwards, N. C.; Eifert, T.; Eigen, G.; Einsweiler, K.; Ekelof, T.; El Kacimi, M.; Ellajosyula, V.; Ellert, M.; Elles, S.; Ellinghaus, F.; Elliot, A. A.; Ellis, N.; Elmsheuser, J.; Elsing, M.; Emeliyanov, D.; Enari, Y.; Endner, O. C.; Endo, M.; Ennis, J. S.; Erdmann, J.; Ereditato, A.; Ernis, G.; Ernst, J.; Ernst, M.; Errede, S.; Ertel, E.; Escalier, M.; Esch, H.; Escobar, C.; Esposito, B.; Etienvre, A. I.; Etzion, E.; Evans, H.; Ezhilov, A.; Fabbri, F.; Fabbri, L.; Facini, G.; Fakhrutdinov, R. M.; Falciano, S.; Falla, R. J.; Faltova, J.; Fang, Y.; Fanti, M.; Farbin, A.; Farilla, A.; Farina, C.; Farooque, T.; Farrell, S.; Farrington, S. M.; Farthouat, P.; Fassi, F.; Fassnacht, P.; Fassouliotis, D.; Faucci Giannelli, M.; Favareto, A.; Fawcett, W. J.; Fayard, L.; Fedin, O. L.; Fedorko, W.; Feigl, S.; Feligioni, L.; Feng, C.; Feng, E. J.; Feng, H.; Fenyuk, A. B.; Feremenga, L.; Fernandez Martinez, P.; Fernandez Perez, S.; Ferrando, J.; Ferrari, A.; Ferrari, P.; Ferrari, R.; Ferreira de Lima, D. E.; Ferrer, A.; Ferrere, D.; Ferretti, C.; Ferretto Parodi, A.; Fiedler, F.; Filipčič, A.; Filipuzzi, M.; Filthaut, F.; Fincke-Keeler, M.; Finelli, K. D.; Fiolhais, M. C. N.; Fiorini, L.; Firan, A.; Fischer, A.; Fischer, C.; Fischer, J.; Fisher, W. C.; Flaschel, N.; Fleck, I.; Fleischmann, P.; Fletcher, G. T.; Fletcher, G.; Fletcher, R. R. M.; Flick, T.; Floderus, A.; Flores Castillo, L. R.; Flowerdew, M. J.; Forcolin, G. T.; Formica, A.; Forti, A.; Foster, A. 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H.; Geng, C.; Gentile, S.; George, S.; Gerbaudo, D.; Gershon, A.; Ghasemi, S.; Ghazlane, H.; Ghneimat, M.; Giacobbe, B.; Giagu, S.; Giannetti, P.; Gibbard, B.; Gibson, S. M.; Gignac, M.; Gilchriese, M.; Gillam, T. P. S.; Gillberg, D.; Gilles, G.; Gingrich, D. M.; Giokaris, N.; Giordani, M. P.; Giorgi, F. M.; Giorgi, F. M.; Giraud, P. F.; Giromini, P.; Giugni, D.; Giuli, F.; Giuliani, C.; Giulini, M.; Gjelsten, B. K.; Gkaitatzis, S.; Gkialas, I.; Gkougkousis, E. L.; Gladilin, L. K.; Glasman, C.; Glatzer, J.; Glaysher, P. C. F.; Glazov, A.; Goblirsch-Kolb, M.; Godlewski, J.; Goldfarb, S.; Golling, T.; Golubkov, D.; Gomes, A.; Gonçalo, R.; Goncalves Pinto Firmino Da Costa, J.; Gonella, L.; Gongadze, A.; González de la Hoz, S.; Gonzalez Parra, G.; Gonzalez-Sevilla, S.; Goossens, L.; Gorbounov, P. A.; Gordon, H. A.; Gorelov, I.; Gorini, B.; Gorini, E.; Gorišek, A.; Gornicki, E.; Goshaw, A. T.; Gössling, C.; Gostkin, M. I.; Goudet, C. R.; Goujdami, D.; Goussiou, A. 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C.; Petit, E.; Petridis, A.; Petridou, C.; Petroff, P.; Petrolo, E.; Petrov, M.; Petrucci, F.; Pettersson, N. E.; Peyaud, A.; Pezoa, R.; Phillips, P. W.; Piacquadio, G.; Pianori, E.; Picazio, A.; Piccaro, E.; Piccinini, M.; Pickering, M. A.; Piegaia, R.; Pilcher, J. E.; Pilkington, A. D.; Pin, A. W. J.; Pina, J.; Pinamonti, M.; Pinfold, J. L.; Pingel, A.; Pires, S.; Pirumov, H.; Pitt, M.; Plazak, L.; Pleier, M.-A.; Pleskot, V.; Plotnikova, E.; Plucinski, P.; Pluth, D.; Poettgen, R.; Poggioli, L.; Pohl, D.; Polesello, G.; Poley, A.; Policicchio, A.; Polifka, R.; Polini, A.; Pollard, C. S.; Polychronakos, V.; Pommès, K.; Pontecorvo, L.; Pope, B. G.; Popeneciu, G. A.; Popovic, D. S.; Poppleton, A.; Pospisil, S.; Potamianos, K.; Potrap, I. N.; Potter, C. J.; Potter, C. T.; Poulard, G.; Poveda, J.; Pozdnyakov, V.; Pozo Astigarraga, M. E.; Pralavorio, P.; Pranko, A.; Prell, S.; Price, D.; Price, L. E.; Primavera, M.; Prince, S.; Proissl, M.; Prokofiev, K.; Prokoshin, F.; Protopopescu, S.; Proudfoot, J.; Przybycien, M.; Puddu, D.; Puldon, D.; Purohit, M.; Puzo, P.; Qian, J.; Qin, G.; Qin, Y.; Quadt, A.; Quayle, W. B.; Queitsch-Maitland, M.; Quilty, D.; Raddum, S.; Radeka, V.; Radescu, V.; Radhakrishnan, S. K.; Radloff, P.; Rados, P.; Ragusa, F.; Rahal, G.; Raine, J. A.; Rajagopalan, S.; Rammensee, M.; Rangel-Smith, C.; Ratti, M. G.; Rauscher, F.; Rave, S.; Ravenscroft, T.; Raymond, M.; Read, A. L.; Readioff, N. P.; Rebuzzi, D. M.; Redelbach, A.; Redlinger, G.; Reece, R.; Reeves, K.; Rehnisch, L.; Reichert, J.; Reisin, H.; Rembser, C.; Ren, H.; Rescigno, M.; Resconi, S.; Rezanova, O. L.; Reznicek, P.; Rezvani, R.; Richter, R.; Richter, S.; Richter-Was, E.; Ricken, O.; Ridel, M.; Rieck, P.; Riegel, C. J.; Rieger, J.; Rifki, O.; Rijssenbeek, M.; Rimoldi, A.; Rinaldi, L.; Ristić, B.; Ritsch, E.; Riu, I.; Rizatdinova, F.; Rizvi, E.; Rizzi, C.; Robertson, S. H.; Robichaud-Veronneau, A.; Robinson, D.; Robinson, J. E. M.; Robson, A.; Roda, C.; Rodina, Y.; Rodriguez Perez, A.; Rodriguez Rodriguez, D.; Roe, S.; Rogan, C. S.; RØhne, O.; Romaniouk, A.; Romano, M.; Romano Saez, S. M.; Romero Adam, E.; Rompotis, N.; Ronzani, M.; Roos, L.; Ros, E.; Rosati, S.; Rosbach, K.; Rose, P.; Rosenthal, O.; Rossetti, V.; Rossi, E.; Rossi, L. P.; Rosten, J. H. N.; Rosten, R.; Rotaru, M.; Roth, I.; Rothberg, J.; Rousseau, D.; Royon, C. R.; Rozanov, A.; Rozen, Y.; Ruan, X.; Rubbo, F.; Rubinskiy, I.; Rud, V. I.; Rudolph, M. S.; Rühr, F.; Ruiz-Martinez, A.; Rurikova, Z.; Rusakovich, N. A.; Ruschke, A.; Russell, H. L.; Rutherfoord, J. P.; Ruthmann, N.; Ryabov, Y. F.; Rybar, M.; Rybkin, G.; Ryu, S.; Ryzhov, A.; Saavedra, A. F.; Sabato, G.; Sacerdoti, S.; Sadrozinski, H. F.-W.; Sadykov, R.; Safai Tehrani, F.; Saha, P.; Sahinsoy, M.; Saimpert, M.; Saito, T.; Sakamoto, H.; Sakurai, Y.; Salamanna, G.; Salamon, A.; Salazar Loyola, J. E.; Salek, D.; Sales De Bruin, P. H.; Salihagic, D.; Salnikov, A.; Salt, J.; Salvatore, D.; Salvatore, F.; Salvucci, A.; Salzburger, A.; Sammel, D.; Sampsonidis, D.; Sanchez, A.; Sánchez, J.; Sanchez Martinez, V.; Sandaker, H.; Sandbach, R. L.; Sander, H. G.; Sanders, M. P.; Sandhoff, M.; Sandoval, C.; Sandstroem, R.; Sankey, D. P. C.; Sannino, M.; Sansoni, A.; Santoni, C.; Santonico, R.; Santos, H.; Santoyo Castillo, I.; Sapp, K.; Sapronov, A.; Saraiva, J. G.; Sarrazin, B.; Sasaki, O.; Sasaki, Y.; Sato, K.; Sauvage, G.; Sauvan, E.; Savage, G.; Savard, P.; Sawyer, C.; Sawyer, L.; Saxon, J.; Sbarra, C.; Sbrizzi, A.; Scanlon, T.; Scannicchio, D. A.; Scarcella, M.; Scarfone, V.; Schaarschmidt, J.; Schacht, P.; Schaefer, D.; Schaefer, R.; Schaeffer, J.; Schaepe, S.; Schaetzel, S.; Schäfer, U.; Schaffer, A. C.; Schaile, D.; Schamberger, R. D.; Scharf, V.; Schegelsky, V. A.; Scheirich, D.; Schernau, M.; Schiavi, C.; Schillo, C.; Schioppa, M.; Schlenker, S.; Schmieden, K.; Schmitt, C.; Schmitt, S.; Schmitz, S.; Schneider, B.; Schnellbach, Y. J.; Schnoor, U.; Schoeffel, L.; Schoening, A.; Schoenrock, B. D.; Schopf, E.; Schorlemmer, A. L. S.; Schott, M.; Schovancova, J.; Schramm, S.; Schreyer, M.; Schuh, N.; Schultens, M. J.; Schultz-Coulon, H.-C.; Schulz, H.; Schumacher, M.; Schumm, B. A.; Schune, Ph.; Schwanenberger, C.; Schwartzman, A.; Schwarz, T. A.; Schwegler, Ph.; Schweiger, H.; Schwemling, Ph.; Schwienhorst, R.; Schwindling, J.; Schwindt, T.; Sciolla, G.; Scuri, F.; Scutti, F.; Searcy, J.; Seema, P.; Seidel, S. C.; Seiden, A.; Seifert, F.; Seixas, J. M.; Sekhniaidze, G.; Sekhon, K.; Sekula, S. J.; Seliverstov, D. M.; Semprini-Cesari, N.; Serfon, C.; Serin, L.; Serkin, L.; Sessa, M.; Seuster, R.; Severini, H.; Sfiligoj, T.; Sforza, F.; Sfyrla, A.; Shabalina, E.; Shaikh, N. W.; Shan, L. Y.; Shang, R.; Shank, J. T.; Shapiro, M.; Shatalov, P. B.; Shaw, K.; Shaw, S. M.; Shcherbakova, A.; Shehu, C. Y.; Sherwood, P.; Shi, L.; Shimizu, S.; Shimmin, C. O.; Shimojima, M.; Shiyakova, M.; Shmeleva, A.; Shoaleh Saadi, D.; Shochet, M. J.; Shojaii, S.; Shrestha, S.; Shulga, E.; Shupe, M. A.; Sicho, P.; Sidebo, P. E.; Sidiropoulou, O.; Sidorov, D.; Sidoti, A.; Siegert, F.; Sijacki, Dj.; Silva, J.; Silverstein, S. B.; Simak, V.; Simard, O.; Simic, Lj.; Simion, S.; Simioni, E.; Simmons, B.; Simon, D.; Simon, M.; Sinervo, P.; Sinev, N. B.; Sioli, M.; Siragusa, G.; Sivoklokov, S. Yu.; Sjölin, J.; Sjursen, T. B.; Skinner, M. B.; Skottowe, H. P.; Skubic, P.; Slater, M.; Slavicek, T.; Slawinska, M.; Sliwa, K.; Slovak, R.; Smakhtin, V.; Smart, B. H.; Smestad, L.; Smirnov, S. Yu.; Smirnov, Y.; Smirnova, L. N.; Smirnova, O.; Smith, M. N. K.; Smith, R. W.; Smizanska, M.; Smolek, K.; Snesarev, A. A.; Snidero, G.; Snyder, S.; Sobie, R.; Socher, F.; Soffer, A.; Soh, D. A.; Sokhrannyi, G.; Solans Sanchez, C. A.; Solar, M.; Soldatov, E. Yu.; Soldevila, U.; Solodkov, A. A.; Soloshenko, A.; Solovyanov, O. V.; Solovyev, V.; Sommer, P.; Son, H.; Song, H. Y.; Sood, A.; Sopczak, A.; Sopko, V.; Sorin, V.; Sosa, D.; Sotiropoulou, C. L.; Soualah, R.; Soukharev, A. M.; South, D.; Sowden, B. C.; Spagnolo, S.; Spalla, M.; Spangenberg, M.; Spanò, F.; Sperlich, D.; Spettel, F.; Spighi, R.; Spigo, G.; Spiller, L. A.; Spousta, M.; St. Denis, R. D.; Stabile, A.; Stahlman, J.; Stamen, R.; Stamm, S.; Stanecka, E.; Stanek, R. W.; Stanescu, C.; Stanescu-Bellu, M.; Stanitzki, M. M.; Stapnes, S.; Starchenko, E. A.; Stark, G. H.; Stark, J.; Staroba, P.; Starovoitov, P.; Stärz, S.; Staszewski, R.; Steinberg, P.; Stelzer, B.; Stelzer, H. J.; Stelzer-Chilton, O.; Stenzel, H.; Stewart, G. A.; Stillings, J. A.; Stockton, M. C.; Stoebe, M.; Stoicea, G.; Stolte, P.; Stonjek, S.; Stradling, A. R.; Straessner, A.; Stramaglia, M. E.; Strandberg, J.; Strandberg, S.; Strandlie, A.; Strauss, M.; Strizenec, P.; Ströhmer, R.; Strom, D. M.; Stroynowski, R.; Strubig, A.; Stucci, S. A.; Stugu, B.; Styles, N. A.; Su, D.; Su, J.; Subramaniam, R.; Suchek, S.; Sugaya, Y.; Suk, M.; Sulin, V. V.; Sultansoy, S.; Sumida, T.; Sun, S.; Sun, X.; Sundermann, J. E.; Suruliz, K.; Susinno, G.; Sutton, M. R.; Suzuki, S.; Svatos, M.; Swiatlowski, M.; Sykora, I.; Sykora, T.; Ta, D.; Taccini, C.; Tackmann, K.; Taenzer, J.; Taffard, A.; Tafirout, R.; Taiblum, N.; Takai, H.; Takashima, R.; Takeda, H.; Takeshita, T.; Takubo, Y.; Talby, M.; Talyshev, A. A.; Tam, J. Y. C.; Tan, K. G.; Tanaka, J.; Tanaka, R.; Tanaka, S.; Tannenwald, B. B.; Tapia Araya, S.; Tapprogge, S.; Tarem, S.; Tartarelli, G. F.; Tas, P.; Tasevsky, M.; Tashiro, T.; Tassi, E.; Tavares Delgado, A.; Tayalati, Y.; Taylor, A. C.; Taylor, G. N.; Taylor, P. T. E.; Taylor, W.; Teischinger, F. A.; Teixeira-Dias, P.; Temming, K. K.; Temple, D.; Ten Kate, H.; Teng, P. K.; Teoh, J. J.; Tepel, F.; Terada, S.; Terashi, K.; Terron, J.; Terzo, S.; Testa, M.; Teuscher, R. J.; Theveneaux-Pelzer, T.; Thomas, J. P.; Thomas-Wilsker, J.; Thompson, E. N.; Thompson, P. D.; Thompson, R. J.; Thompson, A. S.; Thomsen, L. A.; Thomson, E.; Thomson, M.; Tibbetts, M. J.; Ticse Torres, R. E.; Tikhomirov, V. O.; Tikhonov, Yu. A.; Timoshenko, S.; Tipton, P.; Tisserant, S.; Todome, K.; Todorov, T.; Todorova-Nova, S.; Tojo, J.; Tokár, S.; Tokushuku, K.; Tolley, E.; Tomlinson, L.; Tomoto, M.; Tompkins, L.; Toms, K.; Tong, B.; Torrence, E.; Torres, H.; Torró Pastor, E.; Toth, J.; Touchard, F.; Tovey, D. R.; Trefzger, T.; Tricoli, A.; Trigger, I. M.; Trincaz-Duvoid, S.; Tripiana, M. F.; Trischuk, W.; Trocmé, B.; Trofymov, A.; Troncon, C.; Trottier-McDonald, M.; Trovatelli, M.; Truong, L.; Trzebinski, M.; Trzupek, A.; Tseng, J. C.-L.; Tsiareshka, P. V.; Tsipolitis, G.; Tsirintanis, N.; Tsiskaridze, S.; Tsiskaridze, V.; Tskhadadze, E. G.; Tsui, K. M.; Tsukerman, I. I.; Tsulaia, V.; Tsuno, S.; Tsybychev, D.; Tudorache, A.; Tudorache, V.; Tuna, A. N.; Tupputi, S. A.; Turchikhin, S.; Turecek, D.; Turgeman, D.; Turra, R.; Turvey, A. J.; Tuts, P. M.; Tyndel, M.; Ucchielli, G.; Ueda, I.; Ueno, R.; Ughetto, M.; Ukegawa, F.; Unal, G.; Undrus, A.; Unel, G.; Ungaro, F. C.; Unno, Y.; Unverdorben, C.; Urban, J.; Urquijo, P.; Urrejola, P.; Usai, G.; Usanova, A.; Vacavant, L.; Vacek, V.; Vachon, B.; Valderanis, C.; Valdes Santurio, E.; Valencic, N.; Valentinetti, S.; Valero, A.; Valery, L.; Valkar, S.; Vallecorsa, S.; Valls Ferrer, J. A.; Van Den Wollenberg, W.; Van Der Deijl, P. C.; van der Geer, R.; van der Graaf, H.; van Eldik, N.; van Gemmeren, P.; Van Nieuwkoop, J.; van Vulpen, I.; van Woerden, M. C.; Vanadia, M.; Vandelli, W.; Vanguri, R.; Vaniachine, A.; Vankov, P.; Vardanyan, G.; Vari, R.; Varnes, E. W.; Varol, T.; Varouchas, D.; Vartapetian, A.; Varvell, K. E.; Vasquez, J. G.; Vazeille, F.; Vazquez Schroeder, T.; Veatch, J.; Veloce, L. M.; Veloso, F.; Veneziano, S.; Ventura, A.; Venturi, M.; Venturi, N.; Venturini, A.; Vercesi, V.; Verducci, M.; Verkerke, W.; Vermeulen, J. C.; Vest, A.; Vetterli, M. C.; Viazlo, O.; Vichou, I.; Vickey, T.; Boeriu, O. E. Vickey; Viehhauser, G. H. A.; Viel, S.; Vigani, L.; Vigne, R.; Villa, M.; Villaplana Perez, M.; Vilucchi, E.; Vincter, M. G.; Vinogradov, V. B.; Vittori, C.; Vivarelli, I.; Vlachos, S.; Vlasak, M.; Vogel, M.; Vokac, P.; Volpi, G.; Volpi, M.; von der Schmitt, H.; von Toerne, E.; Vorobel, V.; Vorobev, K.; Vos, M.; Voss, R.; Vossebeld, J. H.; Vranjes, N.; Vranjes Milosavljevic, M.; Vrba, V.; Vreeswijk, M.; Vuillermet, R.; Vukotic, I.; Vykydal, Z.; Wagner, P.; Wagner, W.; Wahlberg, H.; Wahrmund, S.; Wakabayashi, J.; Walder, J.; Walker, R.; Walkowiak, W.; Wallangen, V.; Wang, C.; Wang, C.; Wang, F.; Wang, H.; Wang, H.; Wang, J.; Wang, J.; Wang, K.; Wang, R.; Wang, S. M.; Wang, T.; Wang, T.; Wang, X.; Wanotayaroj, C.; Warburton, A.; Ward, C. P.; Wardrope, D. R.; Washbrook, A.; Watkins, P. M.; Watson, A. T.; Watson, I. J.; Watson, M. F.; Watts, G.; Watts, S.; Waugh, B. M.; Webb, S.; Weber, M. S.; Weber, S. W.; Webster, J. S.; Weidberg, A. R.; Weinert, B.; Weingarten, J.; Weiser, C.; Weits, H.; Wells, P. S.; Wenaus, T.; Wengler, T.; Wenig, S.; Wermes, N.; Werner, M.; Werner, P.; Wessels, M.; Wetter, J.; Whalen, K.; Whallon, N. L.; Wharton, A. M.; White, A.; White, M. J.; White, R.; White, S.; Whiteson, D.; Wickens, F. J.; Wiedenmann, W.; Wielers, M.; Wienemann, P.; Wiglesworth, C.; Wiik-Fuchs, L. A. M.; Wildauer, A.; Wilk, F.; Wilkens, H. G.; Williams, H. H.; Williams, S.; Willis, C.; Willocq, S.; Wilson, J. A.; Wingerter-Seez, I.; Winklmeier, F.; Winston, O. J.; Winter, B. T.; Wittgen, M.; Wittkowski, J.; Wollstadt, S. J.; Wolter, M. W.; Wolters, H.; Wosiek, B. K.; Wotschack, J.; Woudstra, M. J.; Wozniak, K. W.; Wu, M.; Wu, M.; Wu, S. L.; Wu, X.; Wu, Y.; Wyatt, T. R.; Wynne, B. M.; Xella, S.; Xu, D.; Xu, L.; Yabsley, B.; Yacoob, S.; Yakabe, R.; Yamaguchi, D.; Yamaguchi, Y.; Yamamoto, A.; Yamamoto, S.; Yamanaka, T.; Yamauchi, K.; Yamazaki, Y.; Yan, Z.; Yang, H.; Yang, H.; Yang, Y.; Yang, Z.; Yao, W.-M.; Yap, Y. C.; Yasu, Y.; Yatsenko, E.; Yau Wong, K. H.; Ye, J.; Ye, S.; Yeletskikh, I.; Yen, A. L.; Yildirim, E.; Yorita, K.; Yoshida, R.; Yoshihara, K.; Young, C.; Young, C. J. S.; Youssef, S.; Yu, D. R.; Yu, J.; Yu, J. M.; Yu, J.; Yuan, L.; Yuen, S. P. Y.; Yusuff, I.; Zabinski, B.; Zaidan, R.; Zaitsev, A. M.; Zakharchuk, N.; Zalieckas, J.; Zaman, A.; Zambito, S.; Zanello, L.; Zanzi, D.; Zeitnitz, C.; Zeman, M.; Zemla, A.; Zeng, J. C.; Zeng, Q.; Zengel, K.; Zenin, O.; Ženiš, T.; Zerwas, D.; Zhang, D.; Zhang, F.; Zhang, G.; Zhang, H.; Zhang, J.; Zhang, L.; Zhang, R.; Zhang, R.; Zhang, X.; Zhang, Z.; Zhao, X.; Zhao, Y.; Zhao, Z.; Zhemchugov, A.; Zhong, J.; Zhou, B.; Zhou, C.; Zhou, L.; Zhou, L.; Zhou, M.; Zhou, N.; Zhu, C. G.; Zhu, H.; Zhu, J.; Zhu, Y.; Zhuang, X.; Zhukov, K.; Zibell, A.; Zieminska, D.; Zimine, N. I.; Zimmermann, C.; Zimmermann, S.; Zinonos, Z.; Zinser, M.; Ziolkowski, M.; Živković, L.; Zobernig, G.; Zoccoli, A.; zur Nedden, M.; Zurzolo, G.; Zwalinski, L.

    2016-05-01

    This paper discusses various observations on beam-induced and cosmic-ray backgrounds in the ATLAS detector during the LHC 2012 proton-proton run. Building on published results based on 2011 data, the correlations between background and residual pressure of the beam vacuum are revisited. Ghost charge evolution over 2012 and its role for backgrounds are evaluated. New methods to monitor ghost charge with beam-gas rates are presented and observations of LHC abort gap population by ghost charge are discussed in detail. Fake jets from colliding bunches and from ghost charge are analysed with improved methods, showing that ghost charge in individual radio-frequency buckets of the LHC can be resolved. Some results of two short periods of dedicated cosmic-ray background data-taking are shown; in particular cosmic-ray muon induced fake jet rates are compared to Monte Carlo simulations and to the fake jet rates from beam background. A thorough analysis of a particular LHC fill, where abnormally high background was observed, is presented. Correlations between backgrounds and beam intensity losses in special fills with very high β* are studied.

  20. Laser-induced periodic surface structures on 6H-SiC single crystals using temporally delayed femtosecond laser double-pulse trains

    NASA Astrophysics Data System (ADS)

    Song, Juan; Tao, Wenjun; Song, Hui; Gong, Min; Ma, Guohong; Dai, Ye; Zhao, Quanzhong; Qiu, Jianrong

    2016-04-01

    In this paper, a time-delay-adjustable double-pulse train with 800-nm wavelength, 200-fs pulse duration and a repetition rate of 1 kHz, produced by a collinear two-beam optical system like a Mach-Zehnder interferometer, was employed for irradiation of 6H-SiC crystal. The dependence of the induced structures on time delay of double-pulse train for parallel-polarization configuration was studied. The results show that as the time delay of collinear parallel-polarization dual-pulse train increased, the induced near-subwavelength ripples (NSWRs) turn from irregular rippled pattern to regularly periodic pattern and have their grooves much deepened. The characteristics timescale for this transition is about 6.24 ps. Besides, the areas of NSWR were found to decay exponentially for time delay from 0 to 1.24 ps and then slowly increase for time delay from 1.24 to 14.24 ps. Analysis shows that multiphoton ionization effect, grating-assisted surface plasmon coupling effect, and timely intervene of second pulse in a certain physical stage experienced by 6H-SiC excited upon first pulse irradiation may contribute to the transition of morphology details.

  1. Infrared-induced variation of the magnetic properties of a magnetoplasmonic film with a 3D sub-micron periodic triangular roof-type antireflection structure

    PubMed Central

    Tian, Junlong; Zhang, Wang; Huang, Yiqiao; Liu, Qinglei; Wang, Yuhua; Zhang, Zhijian; Zhang, Di

    2015-01-01

    A carbon-matrix nickel composite magnetoplasmonic film with a 3D sub-micron periodic triangular roof-type antireflection structure (SPTAS) was fabricated via a simple and promising method that combines chemosynthesis with biomimetic techniques. The Troides helena (Linnaeus) forewing (T_FW) was chosen as the biomimetic template. The carbon-matrix Ni wing fabricated via electroless Ni deposition for 6 h (CNMF_6h) exhibits enhanced infrared absorption. Over a wavelength range (888–2500 nm), the enhancement of the infrared absorption of CNMF_6h is up to 1.85 times compared with the T_FW. Furthermore, infrared excitation induces a photothermal effect that results in variation in the magnetic properties of the carbon-matrix Ni wing. The magnetic properties were also confirmed using atomic force microscopy (AFM) and magnetic force microscopy (MFM). The good correlation between the AFM and MFM images demonstrates that the surface of the SPTAS of CNMF_6h exhibits strong magnetic properties. The infrared induced photothermal effect that results in magnetic variation is promising for use in the design of novel magnetoplasmonic films with potential applications in infrared information recording and heat-assisted magnetic recording. PMID:25620787

  2. SEM and Raman spectroscopy analyses of laser-induced periodic surface structures grown by ethanol-assisted femtosecond laser ablation of chromium

    NASA Astrophysics Data System (ADS)

    Bashir, Shazia; Shahid Rafique, M.; Nathala, Chandra S. R.; Ajami, Ali; Husinsky, Wolfgang

    2015-05-01

    The effect of fluence and pulse duration on the growth of nanostructures on chromium (Cr) surfaces has been investigated upon irradiation of femtosecond (fs) laser pulses in a liquid confined environment of ethanol. In order to explore the effect of fluence, targets were exposed to 1000 pulses at various peak fluences ranging from 4.7 to 11.8 J cm-2 for pulse duration of ∼25 fs. In order to explore the effect of pulse duration, targets were exposed to fs laser pulses of various pulse durations ranging from 25 to 100 fs, for a constant fluence of 11.8 J cm-2. Surface morphology and structural transformations have been analyzed by scanning electron microscopy and Raman spectroscopy, respectively. After laser irradiation, disordered sputtered surface with intense melting and cracking is obtained at the central ablated areas, which are augmented with increasing laser fluence due to enhanced thermal effects. At the peripheral ablated areas, where local fluence is approximately in the range of 1.4-4 mJ cm-2, very well-defined laser-induced periodic surface structures (LIPSS) with periodicity ranging from 270 to 370 nm along with dot-like structures are formed. As far as the pulse duration is concerned, a significant effect on the surface modification of Cr has been revealed. In the central ablated areas, for the shortest pulse duration (25 fs), only melting has been observed. However, LIPSS with dot-like structures and droplets have been grown for longer pulse durations. The periodicity of LIPSS increases and density of dot-like structures decreases with increasing pulse duration. The chemical and structural modifications of irradiated Cr have been revealed by Raman spectroscopy. It confirms the formation of new bands of chromium oxides and enol complexes or Cr-carbonyl compounds. The peak intensities of identified bands are dependent upon laser fluence and pulse duration.

  3. Antioxidant profile, carbonyl and lipid oxidation markers in the parotid and submandibular glands of rats in different periods of streptozotocin induced diabetes.

    PubMed

    Zalewska, Anna; Knaś, Małgorzata; Maciejczyk, Mateusz; Waszkiewicz, Napoleon; Klimiuk, Anna; Choromańska, Magdalena; Matczuk, Jan; Waszkiel, Danuta; Car, Halina

    2015-09-01

    The aim of this study was to estimate the antioxidants barrier, and the oxidative stress in the salivary glands of rats in different periods of streptozotocin induced diabetes. Rats were divided in: 4 control (C2/4/10/14) and 4 experimental (DM2/4/10/14) groups. Salivary glands were removed 2/4/10/14 weeks after streptozotocin injection. Peroxidase (Px), uric acid (UA), total antioxidant status (TAS), superoxide dismutases (SODs), catalase (CAT), malonylodialdehyde (MDA), advanced glycation end products (AGE) concentrations were examined. TAS, Px were lower in the parotid diabetic glands throughout the whole experiment. TAS in the submandibular diabetic glands was lower in 2nd and 4th and higher in 14th week. Px in the submandibular diabetic glands was reduced in 4th and increased in 14th week. UA was lower in parotid, elevated in submandibular diabetic glands in 4th, 10th, 14th weeks. In the submandibular as compared to parotid glands an increase in TAS and UA was observed in 10th and 14th, Px in 14th week. In all periods, a significant increase in AGE was observed in both diabetic salivary glands. An increase in MDA was observed in the parotid diabetic glands in the 4th, 10th, 14th of the study. In the submandibular glands this increase was observed in the 2nd, 4th, 10th week, in the 14th week, the MDA level was significantly reduced in comparison to the control. The antioxidants of parotid glands are deficient throughout the whole experiment. In the last period submandibular glands copy with free radicals, becoming the main antioxidant's source. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Enhanced Long Term Potentiation and Decreased AMPA Receptor Desensitization in the Acute Period Following a Single Kainate Induced Early Life Seizure

    PubMed Central

    O'Leary, Heather; Bernard, Paul B.; Castano, Anna M.; Benke, Tim A.

    2016-01-01

    Neonatal seizures are associated with long term disabilities including epilepsy and cognitive deficits. Using a neonatal seizure rat model that does not develop epilepsy, but develops a phenotype consistent with other models of intellectual disability (ID) and autism spectrum disorders (ASD), we sought to isolate the acute effects of a single episode of early life seizure on hippocampal CA1 synaptic development and plasticity. We have previously shown chronic changes in glutamatergic synapses, loss of long term potentiation (LTP) and enhanced long term depression (LTD), in the adult male rat ~50 days following kainic acid (KA) induced early life seizure (KA-ELS) in post-natal (P) 7 day old male Sprague-Dawley rats. In the present work, we examined the electrophysiological properties and expression levels of glutamate receptors in the acute period, 2 and 7 days, post KA-ELS. Our results show for the first time enhanced LTP 7 days after KA-ELS, but no change 2 days post KA-ELS. Additionally, we report that ionotropic α-amino-3-hydroxy-5-methyl-isoxazole-propionic acid type glutamate receptor (AMPAR) desensitization is decreased in the same time frame, with no changes in AMPAR expression, phosphorylation, or membrane insertion. Inappropriate enhancement of the synaptic connections in the acute period after the seizure could alter the normal patterning of synaptic development in the hippocampus during this critical period and contribute to learning deficits. Thus, this study demonstrates a novel mechanism by which KA-ELS alters early network properties that potentially lead to adverse outcomes. PMID:26706598

  5. UV-induced formation of pyrimidine dimers in nucleosome core DNA is strongly modulated with a period of 10. 3 bases

    SciTech Connect

    Gale, J.M.; Nissen, K.A.; Smerdon, M.J.

    1987-10-01

    We have determined the distribution of the major UV-induced photoproducts in nucleosome core DNA using the 3'----5' exonuclease activity of T4 DNA polymerase, which has been shown to stop digestion immediately 3' to UV-induced pyrimidine dimers. This assay is extremely sensitive since all DNA fragments without photoproducts (background) are reduced to small oligonucleotides, which can be separated from those fragments containing photoproducts. The results show that the distribution of UV-induced photoproducts (primarily cyclobutane dipyrimidines) is not uniform throughout core DNA but displays a striking 10.3 (+/- 0.1) base periodicity. Furthermore, this characteristic distribution of photoproducts was obtained regardless of whether nucleosome core DNA was isolated from UV-irradiated intact chromatin fibers, histone H1-depleted chromatin fibers, isolated mononucleosomes, or cells in culture. The yield of pyrimidine dimers along the DNA seems to be modulated in a manner that reflects structural features of the nucleosome unit, possibly core histone-DNA interactions, since this pattern was not obtained for UV-irradiated core DNA either free in solution or bound tightly to calcium phosphate crystals. Based on their location relative to DNase I cutting sites, the sites of maximum pyrimidine dimer formation in core DNA mapped to positions where the phosphate backbone is farthest from the core histone surface. These results indicate that within the core region of nucleosomes, histone-DNA interactions significantly alter the quantum yield of cyclobutane dipyrimidines, possibly by restraining conformational changes in the DNA helix required for formation of these photoproducts.

  6. Period Pain

    MedlinePlus

    ... You may also have other symptoms, such as lower back pain, nausea, diarrhea, and headaches. Period pain is not ... Taking a hot bath Doing relaxation techniques, including yoga and meditation You might also try taking over- ...

  7. Periodized wavelets

    SciTech Connect

    Schlossnagle, G.; Restrepo, J.M.; Leaf, G.K.

    1993-12-01

    The properties of periodized Daubechies wavelets on [0,1] are detailed and contrasted against their counterparts which form a basis for L{sup 2}(R). Numerical examples illustrate the analytical estimates for convergence and demonstrate by comparison with Fourier spectral methods the superiority of wavelet projection methods for approximations. The analytical solution to inner products of periodized wavelets and their derivatives, which are known as connection coefficients, is presented, and several tabulated values are included.

  8. Postnatal weight gain induced by overfeeding pups and maternal high-fat diet during the lactation period modulates glucose metabolism and the production of pancreatic and gastrointestinal peptides.

    PubMed

    Du, Qinwen; Hosoda, Hiroshi; Umekawa, Takashi; Kinouchi, Toshi; Ito, Natsuki; Miyazato, Mikiya; Kangawa, Kenji; Ikeda, Tomoaki

    2015-08-01

    The impact of rapid weight gain on glucose metabolism during the early postnatal period remains unclear. We investigated the influence of rapid weight gain under different nutritional conditions on glucose metabolism, focusing on the production of pancreatic and gastric peptides. On postnatal day (PND) 2, C57BL/6N pups were divided into three groups: control (C) pups whose dams were fed a control diet (10%kcal fat) and nursed 10 pups each; maternal high-fat diet (HFD) pups whose dams were fed an HFD (45%kcal fat) and nursed 10 pups each; and overfeeding (OF) pups whose dams were fed the control diet and nursed 4 pups each. Data were collected on PND 7, 14 and 21. The body weight gains of the HFD and OF pups were 1.2 times higher than that of the C pups. On PND 14, the HFD pups had higher blood glucose levels, but there were no significant differences in serum insulin levels between the HFD and C pups. The OF pups had higher blood glucose and serum insulin levels than that of the C pups. Insulin resistance was found in the HFD and OF pups. On PND 14, the content of incretins in the jejunum was increased in the OF pups, and acyl ghrelin in the stomach was upregulated in the HFD and OF pups. These results suggest that neonatal weight gain induced by overfeeding pups and maternal high-fat diet during the early postnatal period modulates the insulin sensitivity and the production of pancreatic and gastrointestinal peptides.

  9. Maternal low protein diet restricted to the preimplantation period induces a gender-specific change on hepatic gene expression in rat fetuses.

    PubMed

    Kwong, Wing Yee; Miller, Daniel J; Wilkins, Adrian P; Dear, Mark S; Wright, J Neville; Osmond, Clive; Zhang, Junlong; Fleming, Tom P

    2007-01-01

    It has been shown previously that maternal low protein diet (LPD) throughout rat gestation altered hepatic gene expression and enzyme activities in offspring. Here, we investigate the effect of maternal LPD (9% casein vs. 18% control) exclusively during the preimplantation period (switched diet group) or provided throughout gestation on hepatic gene expression in day 20 fetuses. Using quantitative competitive PCR, we found that switched diet induced a two-fold increase (P = 0.008) in hepatic gene expression of phosphoenolpyruvate carboxykinase (PEPCK, a rate limiting enzyme for gluconeogenesis) in male fetuses and a 17% increase (P = 0.005) in 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1, acts primarily as a reductase to produce active glucocorticoid) in female liver compared with control fetuses. Maternal LPD administered throughout gestation increased 11beta-HSD1 expression in male fetal liver by 27% (P = 0.042) compared with controls. However, maternal LPD fed for either period did not affect fetal hepatic insulin receptor (IR), glucocorticoid receptor (GR), glycogen synthase (GS) nor placental glucose transporter 1 (Glut1) and 3 (Glut3) transcript levels. The alteration in fetal hepatic gene expression could not be attributed specifically to known regulators including insulin or glucose concentrations in fetal blood nor alteration in cAMP in fetal liver, although a combination of these regulatory factors may be responsible. Fetal hepatic glycogen level was unaffected by maternal diet. The present findings show that the long term potential of the preimplantation embryo is sensitive to maternal LPD such that basal levels of hepatic gene expression in day 20 fetuses are altered in a gender-specific manner.

  10. Role of calcium-activated potassium channels in the genesis of 3,4-diaminopyridine-induced periodic contractions in isolated canine coronary artery smooth muscles.

    PubMed

    Uchida, Yasumi; Maezawa, Yuko; Maezawa, Yoshiro; Uchida, Yasuto; Nakamura, Fumitaka

    2011-09-01

    We found that 3,4-diaminopyridine (3,4-DAP), a voltage-gated potassium channel (K(V)) inhibitor, elicits pH-sensitive periodic contractions (PCs) of coronary smooth muscles. Underlying mechanisms of PCs, however, remained to be elucidated. The present study was performed to examine the roles of ion channels in the genesis of PCs. To determine the electromechanical changes of smooth muscles, isolated coronary arterial rings from beagles were suspended in organ chambers filled with Krebs-Henseleit solution, and 10(-2) M 3,4-DAP was added to elicit PCs. 3,4-DAP caused periodic spike-and-plateau depolarization accompanied by contraction. PCs were not produced when the CaCl(2) concentration in the chamber was ≤ 0.3 × 10(-3) or ≥ 10(-2) M. PCs were eliminated by a CaCl(2) concentration ≥ 5 × 10(-3) M or by lowering pH below 7.20 with HCl and recovered by the addition of iberiotoxin or charybdotoxin, which inhibit large-conductance calcium-activated potassium channels (K(Ca)), or by elevating pH above 7.35 with NaOH. PCs, as well as the spike-and-plateau depolarization, were eliminated by nifedipine, which inhibits L-type voltage-gated calcium channels (Ca(V)). Influx of Ca(2+) through L-type Ca(V), which was opened because closing of K(Ca), secondary to 3,4-DAP-induced closing of K(V), resulted in contraction; the intracellular Ca(2+) increased by this influx opened K(Ca), leading to closure of Ca(V) and consequent cessation of Ca(2+) influx with resultant relaxation. These processes were repeated spontaneously to cause PCs. H(+) and OH(-) were considered to act as the opener and closer of K(Ca), respectively.

  11. Expression of inducible nitric oxide synthase (iNOS) and period 1 (PER1) clock gene products in different sleep stages of patients with cognitive impairment.

    PubMed

    Tseng, Ing-Jy; Liu, Hsing-Cheng; Yuan, Rey-Yue; Sheu, Jau-Jiuan; Yu, Jia-Ming; Hu, Chaur-Jong

    2010-09-01

    Circadian and sleep disturbances are common behavioural and psychological symptoms of dementia; circadian rhythm-related molecules may be altered in dementia patients. This study investigated the expression of the period 1 clock gene product (PER1), which is involved in circadian rhythms, and inducible nitric oxide synthase (iNOS), thought to generate nitric oxide, important in rapid eye movement (REM) sleep regulation. Specifically, we investigated the difference in expression of these two genes between patients with cognitive impairment and controls. We studied iNOS and PER1 mRNA expression using real-time polymerase chain reaction in peripheral leukocytes during REM sleep, non-REM sleep and wake stages in patients with Alzheimer's disease (AD, n=5), patients with mild cognitive impairment (MCI, n=8) and controls (n=9) during polysomnography examination. Expression of iNOS significantly increased during REM sleep in AD patients compared to MCI patients and controls. There were no significant differences in PER1 expression between the three groups, but an increase in PER1 expression during the wake stage was observed for all participants. Increased expression of iNOS during REM sleep of patients with AD might be a compensation mechanism for maintaining REM sleep. However, the precise role of nocturnal expression of iNOS in patients with AD requires further investigation. Copyright 2010 Elsevier Ltd. All rights reserved.

  12. Periodic Polymers

    NASA Astrophysics Data System (ADS)

    Thomas, Edwin

    2013-03-01

    Periodic polymers can be made by self assembly, directed self assembly and by photolithography. Such materials provide a versatile platform for 1, 2 and 3D periodic nano-micro scale composites with either dielectric or impedance contrast or both, and these can serve for example, as photonic and or phononic crystals for electromagnetic and elastic waves as well as mechanical frames/trusses. Compared to electromagnetic waves, elastic waves are both less complex (longitudinal modes in fluids) and more complex (longitudinal, transverse in-plane and transverse out-of-plane modes in solids). Engineering of the dispersion relation between wave frequency w and wave vector, k enables the opening of band gaps in the density of modes and detailed shaping of w(k). Band gaps can be opened by Bragg scattering, anti-crossing of bands and discrete shape resonances. Current interest is in our group focuses using design - modeling, fabrication and measurement of polymer-based periodic materials for applications as tunable optics and control of phonon flow. Several examples will be described including the design of structures for multispectral band gaps for elastic waves to alter the phonon density of states, the creation of block polymer and bicontinuous metal-carbon nanoframes for structures that are robust against ballistic projectiles and quasi-crystalline solid/fluid structures that can steer shock waves.

  13. Periodicity-dependent stiffness of periodic hydrophilic-hydrophobic heteropolymers

    NASA Astrophysics Data System (ADS)

    Chowdhury, Debashish; Stauffer, Dietrich; Strey, Reinhard

    1999-08-01

    From extensive Monte Carlo simulations of a Larson model of perfectly periodic heteropolymers (PHP) in water, a striking stiffening is observed as the period of the alternating hydrophobic and hydrophilic blocks is shortened. At short period and low temperature needlelike conformations are the stable conformations. As temperature is increased thermal fluctuations induce kinks and bends. At large periods compact oligomeric globules are observed. From the generalized Larson prescription, originally developed for modeling surfactant molecules in aqueous solutions, we find that the shorter the period is the more stretched the PHP is. This novel effect is expected to stimulate polymer synthesis and trigger research on the rheology of aqueous periodic heteropolymer solutions.

  14. A critical period in the supraspinal control of pain: opioid-dependent changes in brainstem rostroventral medulla function in preadolescence

    PubMed Central

    Hathway, Gareth J.; Vega-Avelaira, David; Fitzgerald, Maria

    2012-01-01

    We have previously shown that the balance of electrically evoked descending brainstem control of spinal nociceptive reflexes undergoes a switch from excitation to inhibition in preadolescent rats. Here we show that the same developmental switch occurs when μ-opioid receptor agonists are microinjected into the rostroventral medulla (RVM). Microinjections of the μ-opioid receptor agonist [D-Ala2, N-MePhe4, Gly-ol]-enkephalin (DAMGO) into the RVM of lightly anaesthetised adult rats produced a dose-dependent decrease in mechanical nociceptive hindlimb reflex electromyographic activity. However, in preadolescent (postnatal day 21 [P21]) rats, the same doses of DAMGO produced reflex facilitation. RVM microinjection of δ-opioid receptor or GABAA receptor agonists, on the other hand, caused reflex depression at both ages. The μ-opioid receptor-mediated descending facilitation is tonically active in naive preadolescent rats, as microinjection of the μ-opioid receptor antagonist D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2 (CTOP) into the RVM at this age decreases spinal nociceptive reflexes while having no effect in adults. To test whether tonic opioid central activity is required for the preadolescent switch in RVM descending control, naloxone hydrochloride was delivered continuously from subcutaneous osmotic mini-pumps for 7-day periods, at various postnatal stages. Blockade of tonic opioidergic activity from P21 to P28, but not at earlier or later ages, prevented the normal development of descending RVM inhibitory control of spinal nociceptive reflexes. Enhancing opioidergic activity with chronic morphine over P7 to P14 accelerated this development. These results show that descending facilitation of spinal nociception in young animals is mediated by μ-opioid receptor pathways in the RVM. Furthermore, the developmental transition from RVM descending facilitation to inhibition of pain is determined by activity in central opioid networks at a critical period of

  15. Fasting for 3 days during the suckling-weaning transient period in male rats induces metabolic abnormalities in the liver and is associated with impaired glucose tolerance in adulthood.

    PubMed

    Ikeda, Misa; Honma, Kazue; Mochizuki, Kazuki; Goda, Toshinao

    2016-04-01

    Recent studies suggest that nutritional status during developmental periods is associated with subsequent development of metabolic abnormalities. In this study, we examined whether malnutrition by fasting for 3 days during the suckling-weaning transient period induces subsequent development of metabolic abnormalities in rats. Male Sprague-Dawley rats were fasted for 3 days during the suckling-weaning transient period. They are subsequently fed a high-fat, high-sucrose (HF) or low-fat, high-starch (LF) diet for 14 weeks from 17 weeks of age, and the liver and blood samples were collected for measuring mRNA and protein levels of metabolic genes and blood concentrations of glucose and insulin, respectively. Fasting for 3 days during the suckling-weaning transient period induced impaired glucose tolerance in rats fed the LF diet in adulthood. Liver triglycerides in rats fed the HF diet in adulthood increased to 140 % in rats fasted for 3 days during the suckling-weaning transient period compared with those non-fasted. Furthermore, liver expression of FBP1 and ACCα genes in adult rats fed the LF diet increased to 125 and 145 %, respectively, in rats fasted for 3 days during the suckling-weaning transient period compared to non-fasted rats. PEPCK1 protein expression levels in rats fed the LF diet were higher in rats fasted for 3 days during the suckling-weaning transient period than in non-fasted rats. Fasting for 3 days in rats during the suckling-weaning transient period enhances metabolic abnormalities in animals fed a HF or LF diet in adulthood by confounding metabolism of lipid and sugar in the liver.

  16. Nuclear apoJ: A low dose radiation inducible regulator of cell death. Final report for period September 15, 1998 - September 14, 2001

    SciTech Connect

    Aronow, Bruce J.

    2002-04-19

    This project was based on preliminary data that was published by Dr. Boothman (Yang et al. 2000) which indicated a strong induction of apoJ gene expression, increased secretion of the protein, and accumulation of an apparently somewhat different form of the apoJ protein in the nucleus of MCF-7 breast carcinoma cells undergoing response to DNA damage. A clone expressing apoJ protein was isolated that was capable of interacting with Ku80, a component of the double strand break repair complex that is essential for the successful repair of rearranging immunoglobulin and T-cell receptor genes as evidenced by failure to produce mature B and T cells in the absence of Ku70. ApoJ clones isolated and characterized by Dr. Boothman bound strongly to a Ku-70 ''bait'' protein. Over-expression of these same clones in a cell line was capable of killing the cell. ApoJ is very strongly induced in many instances of programmed cell death and has been proposed repeatedly to play some sort of effector role in the process. Our principle hypothesis for this study was that the strong induction of the apoJ gene and the particular expression of a nuclear form of the protein was potentially a causal factor in the decision point made by the cell as it attempts to repair double-strand breakage based DNA damage. The hypothesis was that if sufficiently high damage occurred, it would be deleterious to maintain the cell's viability through continued DNA repair. One method to inhibit DNA repair might be by inhibiting proteins such as Ku-70 that are necessary for double-strand break repair. If apoJ does play a critical role in tipping the decision balance over to cell death, we reasoned that deficiency of apoJ would cause increased accumulation of cells with DNA damage and that this might decrease cell death in response to DNA damage and increase tumor occurrence rates. To test this hypothesis and its potential implications, we exposed wildtype and apoJ deficient animals that we constructed through

  17. Power spectra and auto correlation analysis of hyperfine-induced long period oscillations in the tunneling current of coupled quantum dots

    SciTech Connect

    Harack, B.; Leary, A.; Coish, W. A.; Hilke, M.; Yu, G.; Gupta, J. A.; Payette, C.; Austing, D. G.

    2013-12-04

    We outline power spectra and auto correlation analysis performed on temporal oscillations in the tunneling current of coupled vertical quantum dots. The current is monitored for ∼2325 s blocks as the magnetic field is stepped through a high bias feature displaying hysteresis and switching: hallmarks of the hyperfine interaction. Quasi-periodic oscillations of ∼2 pA amplitude and of ∼100 s period are observed in the current inside the hysteretic feature. Compared to the baseline current outside the hysteretic feature the power spectral density is enhanced by up to three orders of magnitude and the auto correlation displays clear long lived oscillations about zero.

  18. Self-organization of a periodic structure between amorphous and crystalline phases in a GeTe thin film induced by femtosecond laser pulse amorphization

    SciTech Connect

    Katsumata, Y.; Morita, T.; Morimoto, Y.; Shintani, T.; Saiki, T.

    2014-07-21

    A self-organized fringe pattern in a single amorphous mark of a GeTe thin film was formed by multiple femtosecond pulse amorphization. Micro Raman measurement indicates that the fringe is a periodic alternation between crystalline and amorphous phases. The period of the fringe is smaller than the irradiation wavelength and the direction is parallel to the polarization direction. Snapshot observation revealed that the fringe pattern manifests itself via a complex but coherent process, which is attributed to crystallization properties unique to a nonthermally amorphized phase and the distinct optical contrast between crystalline and amorphous phases.

  19. Effects of Traumatic Stress Induced in the Juvenile Period on the Expression of Gamma-Aminobutyric Acid Receptor Type A Subunits in Adult Rat Brain

    PubMed Central

    Lu, Cui Yan; Liu, De Xiang; Jiang, Hong; Ho, Cyrus S. H.; Ho, Roger C. M.

    2017-01-01

    Studies have found that early traumatic experience significantly increases the risk of posttraumatic stress disorder (PTSD). Gamma-aminobutyric acid (GABA) deficits were proposed to be implicated in development of PTSD, but the alterations of GABA receptor A (GABAAR) subunits induced by early traumatic stress have not been fully elucidated. Furthermore, previous studies suggested that exercise could be more effective than medications in reducing severity of anxiety and depression but the mechanism is unclear. This study used inescapable foot-shock to induce PTSD in juvenile rats and examined their emotional changes using open-field test and elevated plus maze, memory changes using Morris water maze, and the expression of GABAAR subunits (γ2, α2, and α5) in subregions of the brain in the adulthood using western blotting and immunohistochemistry. We aimed to observe the role of GABAAR subunits changes induced by juvenile trauma in the pathogenesis of subsequent PTSD in adulthood. In addition, we investigated the protective effects of exercise for 6 weeks and benzodiazepine (clonazepam) for 2 weeks. This study found that juvenile traumatic stress induced chronic anxiety and spatial memory loss and reduced expression of GABAAR subunits in the adult rat brains. Furthermore, exercise led to significant improvement as compared to short-term BZ treatment. PMID:28352479

  20. Neuropeptide Y expression confers benzo[a]pyrene induced anxiolytic like behavioral response during early adolescence period of male Wistar rats.

    PubMed

    Das, Saroj Kumar; Patri, Manorama

    2017-02-01

    Environmental neurotoxicant like benzo[a]pyrene (B[a]P) is known to induce neurobehavioral changes. Our previous reports address the adverse effect of B[a]P on the neurobehavioral responses and neuromorphology of sensitive brain regions in adolescent rats. Present study was conducted on male Wistar rat neonates at postnatal day 5 (PND5) to ascertain B[a]P induced anxiolytic like behavioral response could be an outcome of neuropeptide Y (NPY) overexpression in brain. Single intracisternal administration of B[a]P was carried out at PND5 to elucidate the role of NPY on neurobehavioral responses at PND30. The behavioral studies showed anxiolytic like effect of B[a]P in both light and dark box and elevated plus maze tests. Antioxidant assay involving glutathione peroxidase activity was significantly decreased where as lipid peroxidation was significantly augmented in both hippocampus and hypothalamus of B[a]P treated group as compared to naive and control. The neurotransmitter estimation by HPLC-ECD showed significant increase in 5-HT level in both hippocampus and hypothalamus of B[a]P treated group. Significant elevation in NPY expression was observed in both hippocampus and hypothalamus of B[a]P group. Intracellular Ca(2+) estimation using Fura-2AM by fluorometry showed that B[a]P induced increase in Ca(2+) influx was associated with augmented NPY expression in brain. As NPY has orexigenic effect, our result revealed that there was a significant increase in body weight at PND30 following B[a]P administration to rat neonates at PND5. These findings suggested that NPY overexpression in brain regions might be associated with anxiolytic like behavioral response and orexigenic effect in rats following single intracisternal B[a]P administration. Future research directing towards understanding the signaling cascades of B[a]P induced biochemical and neuromorphological alteration might address the independent pathway which induce neurodegeneration despite NPY overexpression in

  1. Giant microwave-induced B -periodic magnetoresistance oscillations in a two-dimensional electron gas with a bridged-gate tunnel point contact

    NASA Astrophysics Data System (ADS)

    Levin, A. D.; Mikhailov, S. A.; Gusev, G. M.; Kvon, Z. D.; Rodyakina, E. E.; Latyshev, A. V.

    2017-02-01

    We have studied the magnetoresistance of a quantum point contact fabricated on a high mobility two-dimensional electron gas (2DEG) exposed to microwave irradiation. The resistance reveals giant B -periodic oscillations with a relative amplitude Δ R /R of up to 700 % resulting from the propagation and interference of the edge magnetoplasmons (EMPs) in the sample. This giant photoconductance is attributed to the considerably large local electron density modulation in the vicinity of the point contact. We have also analyzed the oscillation periods Δ B of the resistance oscillations and, comparing the data with the EMP theory, extracted the EMP interference length L . We have found that the length L substantially exceeds the distance between the contact leads, and rather corresponds to the distance between metallic contact pads measured along the edge of the 2DEG. This resolves existing controversy in the literature and should help to properly design highly sensitive microwave and terahertz spectrometers based on the discussed effect.

  2. [Takotsubo and surroundings. Step by step postpartum stress-induced cardiomyopathy shows its facet. A peculiar case of atypical takotasubo in the peripartum period].

    PubMed

    Russo, Marco; Sappa, Roberta; Gianfagna, Enrico; Salame, Kareem; Sinagra, Gianfranco; Proclemer, Alessandro

    2014-01-01

    Takotsubo syndrome is an acquired cardiomyopathy with transient and reversible left ventricular dysfunction that can mimic an acute coronary syndrome. It is characterized by ECG abnormalities, including minimal ST-segment elevation and T-wave changes, mild troponin elevation, typical left ventricular regional wall motion abnormalities (apical ballooning) and atypical forms (midventricular or reverse apical ballooning) without significant coronary artery stenosis. Its etiology and pathophysiology remain unclear. The sympathetic system seems to play a central role: its exaggerated response to emotional or physical stress triggers may induce microvascular dysfunction and catecholamine-induced cardiotoxicity due to cyclic AMP-mediated calcium overload. We report our experience highlighting the possible pathophysiological and clinical overlap of emotional-triggered catecholamine cardiotoxicity, arterial hypertension and physiological cardiovascular overload in pregnancy describing an atypical case of takotsubo cardiomyopathy with diffuse left ventricular hypokinesia at onset and subsequent evolution to apical ballooning.

  3. Period-three route to chaos induced by a cyclic-fold bifurcation in passive dynamic walking of a compass-gait biped robot

    NASA Astrophysics Data System (ADS)

    Gritli, Hassène; Khraief, Nahla; Belghith, Safya

    2012-11-01

    This paper presents a study of the passive dynamic walking of a compass-gait biped robot as it goes down an inclined plane. This biped robot is a two-degrees-of-freedom mechanical system modeled by an impulsive hybrid nonlinear dynamics with unilateral constraints. It is well-known to possess periodic as well as chaotic gaits and to possess only one stable gait for a given set of parameters. The main contribution of this paper is the finding of a window in the parameters space of the compass-gait model where there is multistability. Using constraints of a grazing bifurcation on the basis of a shooting method and the Davidchack-Lai scheme, we show that, depending on initial conditions, new passive walking patterns can be observed besides those already known. Through bifurcation diagrams and Floquet multipliers, we show that a pair of stable and unstable period-three gait patterns is generated through a cyclic-fold bifurcation. We show also that the stable period-three orbit generates a route to chaos.

  4. Planetary period oscillations in Saturn's magnetosphere: Examining the relationship between abrupt changes in behavior and solar wind-induced magnetospheric compressions and expansions

    NASA Astrophysics Data System (ADS)

    Provan, G.; Tao, C.; Cowley, S. W. H.; Dougherty, M. K.; Coates, A. J.

    2015-11-01

    We examine planetary period oscillations (PPOs) observed in Saturn's magnetospheric magnetic field data from the time of Saturn's equinox in 2009. In particular, we focus on the time period commencing February 2011, when the oscillations started to display sudden and unexpected changes in behavior at ~100-200 day intervals. These were characterized by large simultaneous changes in the amplitude of the northern and southern PPO systems, together with small changes in period and jumps in phase. Nine significant abrupt changes have been observed in the postequinox interval to date, commencing as the Sun started to emerge from a long extended solar minimum. We perform a statistical study to determine whether these modulations in PPO behavior were associated with changes in the solar and/or upstream solar wind conditions. We report that the upstream solar wind conditions show elevated values of solar wind dynamic pressure and density around the time of PPO behavioral transitions, as opposed to before and after these times. We suggest that abrupt changes in PPO behavior may be related to significant changes in the size of the Saturnian magnetosphere in response to varying solar wind conditions.

  5. Cells anticipate periodic events

    NASA Astrophysics Data System (ADS)

    Nakagaki, Toshiyuki

    2009-03-01

    We show that an amoeboid organism can anticipate the timing of periodic events. The plasmodium of the true slime mold Physarum polycephalum moves rapidly under favourable conditions, but stops moving when transferred to less-favourable conditions. Plasmodia exposed to unfavourable conditions, presented in three consecutive pulses at constant intervals, reduced their locomotive speed in response to each episode. When subsequently subjected to favourable conditions, the plasmodia spontaneously reduced their locomotive speed at the time point when the next unfavourable episode would have occurred. This implied anticipation of impending environmental change. After this behaviour had been evoked several times, the locomotion of the plasmodia returned to normal; however, the anticipatory response could subsequently be induced by a single unfavourable pulse, implying recall of the memorized periodicity. We explored the mechanisms underlying these behaviours from a dynamical systems perspective. Our results hint at the cellular origins of primitive intelligence and imply that simple dynamics might be sufficient to explain its emergence.

  6. Periodically poled silicon

    NASA Astrophysics Data System (ADS)

    Hon, Nick K.; Tsia, Kevin K.; Solli, Daniel R.; Khurgin, Jacob B.; Jalali, Bahram

    2010-02-01

    Bulk centrosymmetric silicon lacks second-order optical nonlinearity χ(2) - a foundational component of nonlinear optics. Here, we propose a new class of photonic device which enables χ(2) as well as quasi-phase matching based on periodic stress fields in silicon - periodically-poled silicon (PePSi). This concept adds the periodic poling capability to silicon photonics, and allows the excellent crystal quality and advanced manufacturing capabilities of silicon to be harnessed for devices based on χ(2)) effects. The concept can also be simply achieved by having periodic arrangement of stressed thin films along a silicon waveguide. As an example of the utility, we present simulations showing that mid-wave infrared radiation can be efficiently generated through difference frequency generation from near-infrared with a conversion efficiency of 50% based on χ(2) values measurements for strained silicon reported in the literature [Jacobson et al. Nature 441, 199 (2006)]. The use of PePSi for frequency conversion can also be extended to terahertz generation. With integrated piezoelectric material, dynamically control of χ(2)nonlinearity in PePSi waveguide may also be achieved. The successful realization of PePSi based devices depends on the strength of the stress induced χ(2) in silicon. Presently, there exists a significant discrepancy in the literature between the theoretical and experimentally measured values. We present a simple theoretical model that produces result consistent with prior theoretical works and use this model to identify possible reasons for this discrepancy.

  7. Controls on geyser periodicity

    USGS Publications Warehouse

    Ingebritsen, S.E.; Rojstaczer, S.A.

    1993-01-01

    Geyser eruption frequency is not constant over time and has been shown to vary with small (???10-6) strains induced by seismic events, atmospheric loading, and Earth tides. The geyser system is approximated as a permeable conduit of intensely fractured rock surrounded by a less permeable rock matrix. Numerical simulation of this conceptual model yields a set of parameters that controls geyser existence and periodicity. Much of the responsiveness to remote seismicity and other small strains in the Earth can be explained in terms of variations in permeability and lateral recharge rates.

  8. Controls on geyser periodicity.

    PubMed

    Ingebritsen, S E; Rojstaczer, S A

    1993-11-05

    Geyser eruption frequency is not constant over time and has been shown to vary with small (induced by seismic events, atmospheric loading, and Earth tides. The geyser system is approximated as a permeable conduit of intensely fractured rock surrounded by a less permeable rock matrix. Numerical simulation of this conceptual model yields a set of parameters that controls geyser existence and periodicity. Much of the responsiveness to remote seismicity and other small strains in the Earth can be explained in terms of variations in permeability and lateral recharge rates.

  9. The effect of repeated administrations of llama ovulation-inducing factor (OIF/NGF) during the peri-ovulatory period on corpus luteum development and function in llamas.

    PubMed

    Fernández, A; Ulloa-Leal, C; Silva, M; Norambuena, C; Adams, G P; Guerra, M; Ratto, M H

    2014-10-01

    The objective of the study was to test the hypothesis that repeated administrations of OIF/NGF during the peri-ovulatory period (pre-ovulatory, ovulatory, early post-ovulatory), will enhance the luteotrophic effect in llamas. Female llamas were examined daily by transrectal ultrasonography in B- and Doppler-mode using a scanner equipped with a 7.5-MHz linear-array transducer to monitor ovarian follicle and luteal dynamics. When a growing follicle ≥7mm was detected, llamas were assigned randomly to one of the three groups and given 1mg of purified OIF/NGF im (intramuscular) (a) pre-ovulation (single dose; n=12), (b) pre-ovulation and at the time of ovulation (2 doses, n=10), or (c) pre-ovulation, at the time of ovulation, and 24h after ovulation (3 doses, n=10). The pre-ovulatory follicle diameter at the time of treatment, ovulation rate and the first day of CL detection did not differ (P=0.3) among groups. However, maximum CL diameter was greatest (P=0.003) in llamas in the 2-dose group, and smallest in the 3-dose group. Accordingly, the 2 dose-group had the largest day-to-day profile for CL diameter (P<0.01), area of CL vascularization (<0.01), and plasma progesterone concentration (P=0.01) compared to the other groups. Interestingly, the luteal response to 3-doses of OIF/NGF during the peri-ovulatory period was not different from a single dose. In conclusion, OIF/NGF isolated from llama seminal plasma is luteotrophic and the effect on CL size and function is affected by the number and timing of treatments during the peri-ovulatory period.

  10. Critical periods during the in situ repair of radiation-induced DNA damage in rat cerebellar neurons and 9L brain tumor cells

    SciTech Connect

    Wierowski, J.V.; Thomas, R.R.; Ritter, P.; Wheeler, K.T.

    1982-06-01

    The consequences of delivering a second 1250-rad dose at various times during and after the repair of DNA damage produced by an initial 1250-rad dose were assessed in intracerebral 9L tumor cells and rat cerebellar neurons by measuring the sedimentation properties of their DNA through alkaline sucrose gradients in zonal rotors with slow gradient reorienting capabilities.In cerebellar neurons, separating the two doses by 15 min resulted in an accumulation of DNA damage as expressed by an increase in the amount of DNA sedimenting >250 S over that obtained from unirradiated controls. Although not statistically different from unirradiated controls, a slight increase in the amount of fast-sedimenting neuronal DNA also occurred when a 1-hr interval between the two doses was investigated. At intervals of 2 hr or more, no such increase in fast-sedimenting neuronal DNA was observed. None of the periods between doses resulted in an accumulation of DNA damage in intracerebral 9L tumor cells. The accumulation of this type of DNA damage in neurons but not in tumor cells suggests that avoidance of a critical period in neuronal DNA repair may someday be an important concept in the design of brain tumor therapy schedules.

  11. Human bronchial epithelial cell injuries induced by fine particulate matter from sandstorm and non-sandstorm periods: Association with particle constituents.

    PubMed

    Wang, Bin; Li, Ning; Deng, Furong; Buglak, Nicholas; Park, George; Su, Shu; Ren, Aiguo; Shen, Guofeng; Tao, Shu; Guo, Xinbiao

    2016-09-01

    Epidemiological studies have demonstrated the exacerbation of respiratory diseases following sandstorm-derived particulate matter (PM) exposure. The presence of anthropogenic and biological agents on the sandstorm PM and the escalation of PM<2.5μm (PM2.5) pollution in China have led to serious concerns regarding the health effects of PM2.5 during Asian sandstorms. We investigated how changes in PM2.5 composition, as the weather transitioned towards a sandstorm, affected human airway epithelial cells. Six PM2.5 samples covering two sandstorm events and their respective background and transition periods were collected in Baotou, an industrial city near the Gobi Desert in China. PM samples from all three periods had mild cytotoxicity in human bronchial epithelial cell line BEAS-2B, which was positively correlated with the contents of polycyclic aromatic hydrocarbons and several metals. All PM samples potently increased the release of interleukin-6 (IL-6) and interleukin-8 (IL-8). Endotoxin in all samples contributed significantly to the IL-6 response, with only a minor effect on IL-8. Cr was positively correlated with both IL-6 and IL-8 release, while Si was only associated with the increase of IL-6. Our study suggests that local agricultural and industrial surroundings in addition to the sandstorm play important roles in the respiratory effects of sandstorm-derived PM.

  12. Effects of vegetative-periodic-induced rhizosphere variation on the uptake and translocation of metals in Phragmites australis (Cav.) Trin ex. Steudel growing in the Sun Island Wetland.

    PubMed

    Wu, Jieting; Wang, Li; Ma, Fang; Yang, Jixian; Li, Shiyang; Li, Zhe

    2013-05-01

    To evaluate the vegetative periodic effect of rhizosphere on the patterns of metal bioaccumulation, the concentrations of Mg, K, Ca, Mn, Zn, Fe, Cu, Cr, Ni, Cd and Pb in the corresponding rhizosphere soil and tissues of Phragmites australis growing in the Sun Island wetland (Harbin, China) were compared. The concentrations of Zn, Fe, Cu, Cr, Ni, Cd and Pb in roots were higher than in shoots, suggesting that roots are the primary accumulation organs for these metals and there exists an exclusion strategy for metal tolerance. In contrast, the rest of the metals showed an opposite trend, suggesting that they were not restricted in roots. Harvesting would particularly be an effective method to remove Mn from the environment. The concentrations of metals in shoots were generally higher in autumn than in summer, suggesting that Ph. australis possesses an efficient root-to-shoot translocation system, which is activated at the end of the growing season and allows more metals into the senescent tissues. Furthermore, metal bioaccumulation of Ph. australis was affected by vegetative periodic variation through the changing of physicochemical and microbial conditions. The rhizospheric microbial characteristics were significantly related to the concentrations of Mg, K, Zn, Fe and Cu, suggesting that microbial influence on metal accumulation is specific and selective, not eurytopic.

  13. Nonperturbative effects of the periodic potential on the field-induced spin-density wave and the sign of the quantum Hall effect in the quasi-one-dimensional conductor (TMTSF)2ClO4

    NASA Astrophysics Data System (ADS)

    Kishigi, Keita; Hasegawa, Yasumasa

    2007-06-01

    We show that in (TMTSF)2ClO4 the field-induced spin-density wave (FISDW) with negative quantum number (N=-2) of the nesting vector is stabilized in some region in the parameters of magnetic field and the strength of the anion potential, which corresponds to the very recently observed phase diagram of (TMTSF)2ClO4 in the parameter plane of magnetic field vs cooling rate by Matsunaga [J. Phys. IV 131, 269 (2005)]. The spin-density wave is induced by the magnetic field in the quasi-one-dimensional conductors such as (TMTSF)2PF6 and (TMTSF)2ClO4 . The wave vector of the FISDW is quantized and the Hall conductivity is quantized corresponding to the quantum number (N) of the wave vector. In (TMTSF)2ClO4 , the ordering of the anion ClO4 makes the periodic potential, which has been known to drastically affect the FISDW. We study the instability to the FISDW by taking the eigenstates in the magnetic field numerically, with the periodic potential being treated nonperturbatively. We obtain the phase diagram of the quantum number N for FISDW in the quasi-one-dimensional systems in the parameter plane of magnetic field and the strength of the periodic potential, which can be controlled by the cooling rate.

  14. Temporary Depletion of Microglia during the Early Postnatal Period Induces Lasting Sex-Dependent and Sex-Independent Effects on Behavior in Rats

    PubMed Central

    2016-01-01

    Abstract Microglia are the primary immune cells of the brain and function in multiple ways to facilitate proper brain development. However, our current understanding of how these cells influence the later expression of normal behaviors is lacking. Using the laboratory rat, we administered liposomal clodronate centrally to selectively deplete microglia in the developing postnatal brain. We then assessed a range of developmental, juvenile, and adult behaviors. Liposomal clodronate treatment on postnatal days 0, 2, and 4 depleted microglia with recovery by about 10 days of age and induced a hyperlocomotive phenotype, observable in the second postnatal week. Temporary microglia depletion also increased juvenile locomotion in the open field test and decreased anxiety-like behaviors in the open field and elevated plus maze. These same rats displayed reductions in predator odor–induced avoidance behavior, but increased their risk assessment behaviors compared with vehicle-treated controls. In adulthood, postnatal microglia depletion resulted in significant deficits in male-specific sex behaviors. Using factor analysis, we identified two underlying traits—behavioral disinhibition and locomotion—as being significantly altered by postnatal microglia depletion. These findings further implicate microglia as being critically important to the development of juvenile and adult behavior. PMID:27957532

  15. [KINETICS OF PHOTO-INDUCED FREE RADICALS IN THE HUMAN HAIR CHESTNUT COLOR AFTER SHORT PERIODS OF RED, GREEN, BLUE AND WHITE LIGHT EXPOSURE].

    PubMed

    Tskhvediani, N; Chikvaidze, E; Tsibadze, A; Kvachadze, I; Gogoladze, T; Katsitadze, A

    2016-04-01

    The aim of the study was to investigate the kinetics of photo-induced free radicals in the human hair chestnut color with short-term exposure to visible light in different frequency ranges. Studies carried out on human volunteers aged 17-21 years (n=37). Hairs of volunteers of the study were not treated with dyes and other active cosmetic preparations. Hairs bundled in a bun had a length - 1.5 cm, weight - 40 mg. At the beginning background EPR-spectrum of a sample was measured and then hairs were irradiated with visible light (blue, green, red and white) of different wavelength subsequently; exposure duration - 60 minutes; after the exposure the kinetics of photo-induced free radicals was measured within 60 minutes. The radiation source was selected LED array of the four crystals that provides a nearly monochromatic radiation spectrum having no parasitic infrared and ultraviolet radiations. The studies give a reason to assume that the impact on hairs by visible electromagnetic rays a leading factor is their frequency characteristics: on the one hand - the proximity of the blue light to ultraviolet radiation, and on the other - the red light to the infrared range.

  16. Chronic NMDA receptor blockade in early postnatal period, but not in adulthood, impairs methamphetamine-induced conditioned place preference in rats.

    PubMed

    Furuie, Hiroki; Yamada, Kazuo; Ichitani, Yukio

    2016-03-15

    Early postnatal glutamatergic N-methyl-d-aspartate (NMDA) receptor blockade in animals is known to produce various behavioral deficits in adulthood. In the present study rats postnatally (day 7-20) treated chronically with MK-801, an NMDA receptor antagonist, were tested later in adulthood in methamphetamine (MAP)-induced conditioned place preference (CPP) using a unbiased procedure in a three-compartment apparatus. Rats with the same chronic treatment in adulthood were also tested. CPP test consisted of a baseline test before conditioning, place conditioning, and a preference test after conditioning. Rats postnatally treated with MK-801 did not show any evidence of preference for MAP-paired compartment compared with that for unpaired one in the preference test that was shown in rats postnatally treated with saline. On the other hand, rats treated with MK-801 in adulthood were not affected by the treatment and showed significant CPP as was shown in saline-treated control animals. Results suggest the possibility that chronic early postnatal, but not adulthood, NMDA receptor blockade induces persistent deficit of subsequent appetitive classical conditioning. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Long-period helical structures and twist-grain boundary phases induced by chemical substitution in the Mn1 -x(Co,Rh ) xGe chiral magnet

    NASA Astrophysics Data System (ADS)

    Martin, N.; Deutsch, M.; Chaboussant, G.; Damay, F.; Bonville, P.; Fomicheva, L. N.; Tsvyashchenko, A. V.; Rössler, U. K.; Mirebeau, I.

    2017-07-01

    We study the evolution of helical magnetism in MnGe chiral magnet upon partial substitution of Mn for 3 d -Co and 4 d -Rh ions. At high doping levels, we observe spin helices with very long periods—more than ten times larger than in the pure compound—and sizable ordered moments. This behavior calls for a change in the energy balance of interactions leading to the stabilization of the observed magnetic structures. Strikingly, neutron scattering unambiguously shows a double periodicity in the observed spectra at x =0.5 and >0.2 for Co- and Rh-doping, respectively. In analogy with observations made in smectic liquid crystals, we suggest that it may reveal the presence of magnetic "twist grain boundary" phases, involving a dense short-range correlated network of magnetic screw dislocations. The dislocation cores are here tentatively described as smooth textures, made of nonradial double-core skyrmions.

  18. Mitochondrial alternative oxidase acts to dampen the generation of active oxygen species during a period of rapid respiration induced to support a high rate of nutrient uptake.

    PubMed

    Yip, Justine Y. H.; Vanlerberghe, Greg C.

    2001-07-01

    When wild type (wt) tobacco (Nicotiana tabacum L. cv. Petit Havana SR1) suspension cells were grown under phosphate (P) limitation, they contained large amounts of mitochondrial alternative oxidase (AOX). When these cells were resupplied with P, there was a large, immediate and sustained stimulation of respiration to support a period of rapid P uptake. Two lines of evidence suggest that the abundant level of AOX present in wt cells contributed to this stimulated rate of respiration. First, when P-limited transgenic antisense tobacco cells (AS8) lacking AOX were resupplied with P, the stimulation of respiration was much less dramatic even though these cells displayed similar rates of P uptake. Second, while the stimulated rate of respiration in AS8 cells was insensitive (as expected) to the AOX inhibitor n-propyl gallate (nPG), much of the stimulated rate of respiration in wt cells could be inhibited by nPG. Given the non-phosphorylating nature of AOX respiration, wt cells required higher rates of electron transport to O2 than AS8 cells to support similar rates of P uptake. The utilization of AOX by wt cells during P uptake was apparently not occurring because the cytochrome (Cyt) pathway alone could not fully support the rate of P uptake, as the respiration of cells lacking AOX (either untreated AS8 cells or wt cells treated with nPG) supported similar rates of P uptake as wt cells with abundant AOX. Rather, we provide in vivo evidence that the utilization of AOX during the period of high respiration supporting P uptake was to dampen the mitochondrial generation of active oxygen species (AOS).

  19. Field observation of morpho-dynamic processes during storms at a Pacific beach, Japan: Role of long-period waves in storm-induced berm erosion

    PubMed Central

    MIZUGUCHI, Masaru; SEKI, Katsumi

    2015-01-01

    Many ultrasonic wave gages were placed with a small spacing across the swash zone to monitor either sand level or water level. Continuous monitoring conducted for a few years enabled the collection of data on the change in wave properties as well as swash-zone profiles. Data sets including two cases of large-scale berm erosion were analyzed. The results showed that 1) shoreline erosion started when high waves with significant power in long-period (1 to 2 min.) waves reached the top of a well-developed berm with the help of rising tide; 2) the beach in the swash zone was eroded with higher elevation being more depressed, while the bottom elevation just outside the swash zone remained almost unchanged; and 3) erosion stopped in a few hours after the berm was completely eroded or the swash-zone slope became uniformly mild. These findings strongly suggest that long waves play a dominant role in the swash-zone dynamics associated with these erosional events. PMID:25748583

  20. Field observation of morpho-dynamic processes during storms at a Pacific beach, Japan: role of long-period waves in storm-induced berm erosion.

    PubMed

    Mizuguchi, Masaru; Seki, Katsumi

    2015-01-01

    Many ultrasonic wave gages were placed with a small spacing across the swash zone to monitor either sand level or water level. Continuous monitoring conducted for a few years enabled the collection of data on the change in wave properties as well as swash-zone profiles. Data sets including two cases of large-scale berm erosion were analyzed. The results showed that 1) shoreline erosion started when high waves with significant power in long-period (1 to 2 min.) waves reached the top of a well-developed berm with the help of rising tide; 2) the beach in the swash zone was eroded with higher elevation being more depressed, while the bottom elevation just outside the swash zone remained almost unchanged; and 3) erosion stopped in a few hours after the berm was completely eroded or the swash-zone slope became uniformly mild. These findings strongly suggest that long waves play a dominant role in the swash-zone dynamics associated with these erosional events.

  1. Laser-induced interstitial thermotherapy (LITT) for treatment of uterine leiomyomas: 750 myomas were treated by LITT and the results over a five-year period are analyzed

    NASA Astrophysics Data System (ADS)

    Chapman, Roxana

    1997-05-01

    Approximately 750 leiomyomas of 250 symptomatic patients were treated by LITT over a five-year period. Only 12% were lost to follow-up. Most were treated by a combination of the KTP/YAG laser, rarely by one or the other alone, and a few with the diode laser. The fiber optic was inserted 2 cm apart and, depending on the size of the tumor, 480 - 20,000 Joules were required. Most were treated laparoscopically but very large myomas were treated percutaneously under ultrasound control. Symptoms were nearly always relieved and the six failures were found to be due to unrecognized adenomyosis and other associated pathology. Half the patients complaining of infertility became pregnant and, in those whose only pathology had been leiomyomas it approached 90%. Vaginal delivery was not found to be contraindicated. Finally, oestrogen receptors and epidermal growth factor were found to be destroyed. It is concluded that LITT enables leiomyomas of all sizes and locations to be treated by a minimally invasive method with preservation of the uterus.

  2. Investigations of nuclear structure and nuclear reactions induced by complex projectiles. Progress report for the period September 1, 1992--August 31, 1993

    SciTech Connect

    Sarantites, D.G.

    1993-09-06

    This is a progress report on activities of the Washington University group in nuclear reaction studies for the period Sept 1, 1992 to Aug 31, 1993. This group has a research program which touches five areas of nuclear physics: nuclear structure studies at high spin; studies at the interface between structure and reactions; production and study of hot nuclei; reaction mechanism studies; development and use of novel techniques and instrumentation in the above areas of research. Specific activities of the group include in part: superdeformation in {sup 82}Sr; structure of and identical bands in {sup 182}Hg and {sup 178}Pt; a highly deformed band in {sup 136}Pm; particle decay of the {sup 164}Yb compound nucleus; fusion reactions; proton evaporation; two-proton decay of {sup 12}O; modeling and theoretical studies; excited {sup 16}O disassembly into four alpha particles; {sup 209}Bi + {sup 136}Xe collisions at 28.2 MeV/amu; and development work on 4{pi} solid angle gamma detectors, and x-ray detectors.

  3. Elaborate regulations of the predator-induced polyphenism in the water flea Daphnia pulex: kairomone-sensitive periods and life-history tradeoffs.

    PubMed

    Imai, Maki; Naraki, Yuka; Tochinai, Shin; Miura, Toru

    2009-12-01

    Adaptive polyphenism produces alternative phenotypes depending on environmental stimuli. The water flea Daphnia pulex shows predator-induced polyphenism, facultatively forming neckteeth in response to kairomones released by Chaoborus larvae. This study was designed to reveal the regulatory systems producing the defensive morph during embryonic and postembryonic development. As noted previously, the crest epithelium at the site of neckteeth is shown to thicken earlier the neckteeth formation, and the neckteeth number increased until the third instar, and later disappeared. Exposure to kairomone at various time points and intervals during development showed that the signal was required even at early postembryonic stages to maintain neckteeth. Moreover, two different induction methods, i.e. embryonic and maternal exposures, enabled us to discriminate maternal and zygotic effects in response to kairomone. Direct embryonic exposure is shown to be sufficient to form neckteeth without maternal effect although their growth was diminished; namely, there is a trade-off for neckteeth production. However, maternal exposures resulted in larger progenies in smaller numbers, suggesting that the mother daphnids change their reproductive strategy depending on kairomone signals. Taken together, the developmental responses to the presence of predators are regulated elaborately at various levels.

  4. Periodic mechanical stress induces the extracellular matrix expression and migration of rat nucleus pulposus cells by upregulating the expression of intergrin α1 and phosphorylation of downstream phospholipase Cγ1

    PubMed Central

    Gao, Gongming; He, Jin; Nong, Luming; Xie, Hua; Huang, Yongjing; Xu, Nanwei; Zhou, Dong

    2016-01-01

    Intervertebral disk degeneration (IDD) is a major cause of low back pain and an important socioeconomic burden. Degradation of the extracellular matrix (ECM) of nucleus pulposus (NP) cells in the interverterbal disk is important for IDD. Stress of a suitable frequency and amplitude promotes the synthesis of the ECM of NP cells, however, the associated mechanisms remain to be fully elucidated The present study aimed to investigate the effect of integrin α1 on the migration and ECM synthesis of NP cells under soft periodic mechanical stress. Rat NP cells were isolated and plated onto slides, and were then treated with or without the use of a periodic mechanical stress system. The expression levels of integrin α1, α5 and αv, ECM collagen 2A1 (Col2A1) and aggrecan, and the phosphorylation of phospholipase C-γ1 (PLCγ1) were measured using reverse transcription-quantitative polymerase chain reaction and western blot analyses. Cell migration was assayed using a scratch experiment. The results showed that exposure to periodic mechanical stress significantly induced the mRNA expression levels of Col2A1 and aggrecan, cell migration, mRNA expression of integrin α1 and phosphorylation of PLC-γ1 of the NP, compared with the control (P<0.05). Inhibition of the PLCγ1 protein by U73122 significantly decreased the ECM expression under periodic mechanical stress (P<0.05). Small interfering RNA-mediated integrin α1 gene knockdown suppressed the mRNA expression levels of Col2A1 and aggrecan, and suppressed the migration and phosphorylation of PLCγ1 of the NP cells under periodic mechanical stress, compared with the control (P<0.05). In conclusion, periodic mechanical stress induced ECM expression and the migration of NP cells via upregulating the expression of integrin α1 and the phosphorylation of downstream PLCγ1. These findings provide novel information to aid the understanding of the pathogenesis and development of IDD. PMID:27484337

  5. Rhythmic melatonin secretion does not correlate with the expression of arylalkylamine N-acetyltransferase, inducible cyclic amp early repressor, period1 or cryptochrome1 mRNA in the sheep pineal.

    PubMed

    Johnston, J D; Bashforth, R; Diack, A; Andersson, H; Lincoln, G A; Hazlerigg, D G

    2004-01-01

    The pineal gland, through nocturnal melatonin, acts as a neuroendocrine transducer of daily and seasonal time. Melatonin synthesis is driven by rhythmic activation of the rate-limiting enzyme, arylalkylamine N-acetyltransferase (AA-NAT). In ungulates, AA-NAT mRNA is constitutively high throughout the 24-h cycle, and melatonin production is primarily controlled through effects on AA-NAT enzyme activity; this is in contrast to dominant transcriptional control in rodents. To determine whether there has been a selective loss of circadian control of AA-NAT mRNA expression in the sheep pineal, we measured the expression of other genes known to be rhythmic in rodents (inducible cAMP early repressor ICER, the circadian clock genes Period1 and Cryptochrome1, as well as AA-NAT). We first assayed gene expression in pineal glands collected from Soay sheep adapted to short days (Light: dark, 8-h: 16-h), and killed at 4-h intervals through 24-h. We found no evidence for rhythmic expression of ICER, AA-NAT or Cryptochrome1 under these conditions, whilst Period1 showed a low amplitude rhythm of expression, with higher values during the dark period. In a second group of animals, lights out was delayed by 8-h during the final 24-h sampling period, a manipulation that causes an immediate shortening of the period of melatonin secretion. This did not significantly affect the expression of ICER, AA-NAT or Cryptochrome1 in the pineal, whilst a slight suppressive effect on overall Per1 levels was observed. The attenuated response to photoperiod change appears to be specific to the ovine pineal, as the first long day induced rapid changes of Period1 and ICER expression in the hypothalamic suprachiasmatic nuclei and pituitary pars tuberalis, respectively. Overall, our data suggest a general reduction of circadian control of transcript abundance in the ovine pineal gland, consistent with a marked evolutionary divergence in the mechanism regulating melatonin production between terrestrial

  6. Absent menstrual periods - secondary

    MedlinePlus

    Amenorrhea - secondary; No periods - secondary; Absent periods - secondary; Absent menses - secondary; Absence of periods - secondary ... bleeding. When they stop taking these hormones, their periods may not return for more than 6 months. ...

  7. Analysis of the return period and correlation between the reservoir-induced seismic frequency and the water level based on a copula: A case study of the Three Gorges reservoir in China

    NASA Astrophysics Data System (ADS)

    Liu, Xiaofei; Zhang, Qiuwen

    2016-11-01

    Studies have considered the many factors involved in the mechanism of reservoir seismicity. Focusing on the correlation between reservoir-induced seismicity and the water level, this study proposes to utilize copula theory to build a correlation model to analyze their relationships and perform the risk analysis. The sequences of reservoir induced seismicity events from 2003 to 2011 in the Three Gorges reservoir in China are used as a case study to test this new methodology. Next, we construct four correlation models based on the Gumbel, Clayton, Frank copula and M-copula functions and employ four methods to test the goodness of fit: Q-Q plots, the Kolmogorov-Smirnov (K-S) test, the minimum distance (MD) test and the Akaike Information Criterion (AIC) test. Through a comparison of the four models, the M-copula model fits the sample better than the other three models. Based on the M-copula model, we find that, for the case of a sudden drawdown of the water level, the possibility of seismic frequency decreasing obviously increases, whereas for the case of a sudden rising of the water level, the possibility of seismic frequency increasing obviously increases, with the former being greater than the latter. The seismic frequency is mainly distributed in the low-frequency region (Y ⩽ 20) for the low water level and in the middle-frequency region (20 < Y ≤ 80) for both the medium and high water levels; the seismic frequency in the high-frequency region (Y > 80) is the least likely. For the conditional return period, it can be seen that the period of the high-frequency seismicity is much longer than those of the normal and medium frequency seismicity, and the high water level shortens the periods.

  8. Generation of laser-induced periodic surface structures in indium-tin-oxide thin films and two-photon lithography of ma-N photoresist by sub-15 femtosecond laser microscopy for liquid crystal cell application

    NASA Astrophysics Data System (ADS)

    Klötzer, Madlen; Afshar, Maziar; Feili, Dara; Seidel, Helmut; König, Karsten; Straub, Martin

    2015-03-01

    Indium-tin-oxide (ITO) is a widely used electrode material for liquid crystal cell applications because of its transparency in the visible spectral range and its high electrical conductivity. Important examples of applications are displays and optical phase modulators. We report on subwavelength periodic structuring and precise laser cutting of 150 nm thick indium-tin-oxide films on glass substrates, which were deposited by magnetron reactive DC-sputtering from an indiumtin target in a low-pressure oxygen atmosphere. In order to obtain nanostructured electrodes laser-induced periodic surface structures with a period of approximately 100 nm were generated using tightly focused high-repetition rate sub-15 femtosecond pulsed Ti:sapphire laser light, which was scanned across the sample by galvanometric mirrors. Three-dimensional spacers were produced by multiphoton photopolymerization in ma-N 2410 negative-tone photoresist spin-coated on top of the ITO layers. The nanostructured electrodes were aligned in parallel to set up an electrically switchable nematic liquid crystal cell.

  9. Fast excitation variable period wiggler

    SciTech Connect

    van Steenbergen, A.; Gallardo, J.; Romano, T.; Woodle, M.

    1991-01-01

    The design of an easily stackable, variable period length, fast excitation driven wiggler, making use of geometrically alternating substacks of Vanadium Permandur ferromagnetic laminations, interspaced with conductive, non magnetic, laminations which act as eddy current induced field reflectors,'' is discussed and experimental results obtained with short wiggler models are presented.

  10. Fast excitation variable period wiggler

    SciTech Connect

    van Steenbergen, A.; Gallardo, J.; Romano, T.; Woodle, M.

    1991-12-31

    The design of an easily stackable, variable period length, fast excitation driven wiggler, making use of geometrically alternating substacks of Vanadium Permandur ferromagnetic laminations, interspaced with conductive, non magnetic, laminations which act as eddy current induced ``field reflectors,`` is discussed and experimental results obtained with short wiggler models are presented.

  11. Evolution of periodicity in periodical cicadas.

    PubMed

    Ito, Hiromu; Kakishima, Satoshi; Uehara, Takashi; Morita, Satoru; Koyama, Takuya; Sota, Teiji; Cooley, John R; Yoshimura, Jin

    2015-09-14

    Periodical cicadas (Magicicada spp.) in the USA are famous for their unique prime-numbered life cycles of 13 and 17 years and their nearly perfectly synchronized mass emergences. Because almost all known species of cicada are non-periodical, periodicity is assumed to be a derived state. A leading hypothesis for the evolution of periodicity in Magicicada implicates the decline in average temperature during glacial periods. During the evolution of periodicity, the determinant of maturation in ancestral cicadas is hypothesized to have switched from size dependence to time (period) dependence. The selection for the prime-numbered cycles should have taken place only after the fixation of periodicity. Here, we build an individual-based model of cicadas under conditions of climatic cooling to explore the fixation of periodicity. In our model, under cold environments, extremely long juvenile stages lead to extremely low adult densities, limiting mating opportunities and favouring the evolution of synchronized emergence. Our results indicate that these changes, which were triggered by glacial cooling, could have led to the fixation of periodicity in the non-periodical ancestors.

  12. Evolution of periodicity in periodical cicadas

    PubMed Central

    Ito, Hiromu; Kakishima, Satoshi; Uehara, Takashi; Morita, Satoru; Koyama, Takuya; Sota, Teiji; Cooley, John R.; Yoshimura, Jin

    2015-01-01

    Periodical cicadas (Magicicada spp.) in the USA are famous for their unique prime-numbered life cycles of 13 and 17 years and their nearly perfectly synchronized mass emergences. Because almost all known species of cicada are non-periodical, periodicity is assumed to be a derived state. A leading hypothesis for the evolution of periodicity in Magicicada implicates the decline in average temperature during glacial periods. During the evolution of periodicity, the determinant of maturation in ancestral cicadas is hypothesized to have switched from size dependence to time (period) dependence. The selection for the prime-numbered cycles should have taken place only after the fixation of periodicity. Here, we build an individual-based model of cicadas under conditions of climatic cooling to explore the fixation of periodicity. In our model, under cold environments, extremely long juvenile stages lead to extremely low adult densities, limiting mating opportunities and favouring the evolution of synchronized emergence. Our results indicate that these changes, which were triggered by glacial cooling, could have led to the fixation of periodicity in the non-periodical ancestors. PMID:26365061

  13. Cannabis Induced Periodic Catatonia: A Case Report

    ERIC Educational Resources Information Center

    Bajaj, Vikrant; Pathak, Prashant; Mehrotra, Saurabh; Singh, Vijender; Govil, Sandeep; Khanna, Aman

    2011-01-01

    Catatonia is a syndrome of specific motor abnormalities closely associated with disorders in mood, affect, thought and cognition. The principal signs of the disorder are mutism, immobility, negativism, posturing, stereotypy and echo phenomena. Catatonia is commonly seen in various psychiatric disorders, neurological disorders and certain medical…

  14. Cannabis Induced Periodic Catatonia: A Case Report

    ERIC Educational Resources Information Center

    Bajaj, Vikrant; Pathak, Prashant; Mehrotra, Saurabh; Singh, Vijender; Govil, Sandeep; Khanna, Aman

    2011-01-01

    Catatonia is a syndrome of specific motor abnormalities closely associated with disorders in mood, affect, thought and cognition. The principal signs of the disorder are mutism, immobility, negativism, posturing, stereotypy and echo phenomena. Catatonia is commonly seen in various psychiatric disorders, neurological disorders and certain medical…

  15. Chaos in Periodic Discrete Systems

    NASA Astrophysics Data System (ADS)

    Shi, Yuming; Zhang, Lijuan; Yu, Panpan; Huang, Qiuling

    This paper focuses on chaos in periodic discrete systems, whose state space may vary with time. Some close relationships between some chaotic dynamical behaviors of a periodic discrete system and its autonomous induced system are given. Based on these relationships, several criteria of chaos are established and some sufficient conditions for no chaos are given for periodic discrete systems. Further, it is shown that a finite-dimensional linear periodic discrete system is not chaotic in the sense of Li-Yorke or Wiggins. In particular, an interesting problem of whether nonchaotic rules may generate a chaotic system is studied, with some examples provided, one of which surprisingly shows that a composition of globally asymptotically stable maps can be chaotic. In addition, some properties of sign pattern matrices of non-negative square matrices are given for convenience of the study.

  16. Hyperkalemic periodic paralysis

    MedlinePlus

    Periodic paralysis - hyperkalemic; Familial hyperkalemic periodic paralysis; HyperKPP; HyperPP; Gamstorp disease ... factors include having other family members with periodic paralysis. It affects men more often than women.

  17. CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES: A theoretical study of harmonic generation in a short period AlGaN/GaN superlattice induced by a terahertz field

    NASA Astrophysics Data System (ADS)

    Chen, Jun-Feng; Hao, Yue

    2009-12-01

    Based on an improved energy dispersion relation, the terahertz field induced nonlinear transport of miniband electrons in a short period AlGaN/GaN superlattice is theoretically studied in this paper with a semiclassical theory. To a short period superlattice, it is not precise enough to calculate the energy dispersion relation by just using the nearest wells in tight binding method: the next to nearest wells should be considered. The results show that the electron drift velocity is 30% lower under a dc field but 10% higher under an ac field than the traditional simple cosine model obtained from the tight binding method. The influence of the terahertz field strength and frequency on the harmonic amplitude, phase and power efficiency is calculated. The relative power efficiency of the third harmonic reaches the peak value when the dc field strength equals about three times the critical field strength and the ac field strength equals about four times the critical field strength. These results show that the AlGaN/GaN superlattice is a promising candidate to convert radiation of frequency ω to radiation of frequency 3ω or even higher.

  18. Exposure to a Highly Caloric Palatable Diet During Pregestational and Gestational Periods Affects Hypothalamic and Hippocampal Endocannabinoid Levels at Birth and Induces Adiposity and Anxiety-Like Behaviors in Male Rat Offspring.

    PubMed

    Ramírez-López, María Teresa; Vázquez, Mariam; Bindila, Laura; Lomazzo, Ermelinda; Hofmann, Clementine; Blanco, Rosario Noemí; Alén, Francisco; Antón, María; Decara, Juan; Ouro, Daniel; Orio, Laura; Suarez, Juan; Lutz, Beat; Rodríguez de Fonseca, Fernando; Gómez de Heras, Raquel

    2015-01-01

    Exposure to unbalanced diets during pre-gestational and gestational periods may result in long-term alterations in metabolism and behavior. The contribution of the endocannabinoid system to these long-term adaptive responses is unknown. In the present study, we investigated the impact of female rat exposure to a hypercaloric-hypoproteic palatable diet during pre-gestational, gestational and lactational periods on the development of male offspring. In addition, the hypothalamic and hippocampal endocannabinoid contents at birth and the behavioral performance in adulthood were investigated. Exposure to a palatable diet resulted in low weight offspring who exhibited low hypothalamic contents of arachidonic acid and the two major endocannabinoids (anandamide and 2-arachidonoylglycerol) at birth. Palmitoylethanolamide, but not oleoylethanolamide, also decreased. Additionally, pups from palatable diet-fed dams displayed lower levels of anandamide and palmitoylethanolamide in the hippocampus. The low-weight male offspring, born from palatable diet exposed mothers, gained less weight during lactation and although they recovered weight during the post-weaning period, they developed abdominal adiposity in adulthood. These animals exhibited anxiety-like behavior in the elevated plus-maze and open field test and a low preference for a chocolate diet in a food preference test, indicating that maternal exposure to a hypercaloric diet induces long-term behavioral alterations in male offspring. These results suggest that maternal diet alterations in the function of the endogenous cannabinoid system can mediate the observed phenotype of the offspring, since both hypothalamic and hippocampal endocannabinoids regulate feeding, metabolic adaptions to caloric diets, learning, memory, and emotions.

  19. Exposure to a Highly Caloric Palatable Diet During Pregestational and Gestational Periods Affects Hypothalamic and Hippocampal Endocannabinoid Levels at Birth and Induces Adiposity and Anxiety-Like Behaviors in Male Rat Offspring

    PubMed Central

    Ramírez-López, María Teresa; Vázquez, Mariam; Bindila, Laura; Lomazzo, Ermelinda; Hofmann, Clementine; Blanco, Rosario Noemí; Alén, Francisco; Antón, María; Decara, Juan; Ouro, Daniel; Orio, Laura; Suarez, Juan; Lutz, Beat; Rodríguez de Fonseca, Fernando; Gómez de Heras, Raquel

    2016-01-01

    Exposure to unbalanced diets during pre-gestational and gestational periods may result in long-term alterations in metabolism and behavior. The contribution of the endocannabinoid system to these long-term adaptive responses is unknown. In the present study, we investigated the impact of female rat exposure to a hypercaloric-hypoproteic palatable diet during pre-gestational, gestational and lactational periods on the development of male offspring. In addition, the hypothalamic and hippocampal endocannabinoid contents at birth and the behavioral performance in adulthood were investigated. Exposure to a palatable diet resulted in low weight offspring who exhibited low hypothalamic contents of arachidonic acid and the two major endocannabinoids (anandamide and 2-arachidonoylglycerol) at birth. Palmitoylethanolamide, but not oleoylethanolamide, also decreased. Additionally, pups from palatable diet-fed dams displayed lower levels of anandamide and palmitoylethanolamide in the hippocampus. The low-weight male offspring, born from palatable diet exposed mothers, gained less weight during lactation and although they recovered weight during the post-weaning period, they developed abdominal adiposity in adulthood. These animals exhibited anxiety-like behavior in the elevated plus-maze and open field test and a low preference for a chocolate diet in a food preference test, indicating that maternal exposure to a hypercaloric diet induces long-term behavioral alterations in male offspring. These results suggest that maternal diet alterations in the function of the endogenous cannabinoid system can mediate the observed phenotype of the offspring, since both hypothalamic and hippocampal endocannabinoids regulate feeding, metabolic adaptions to caloric diets, learning, memory, and emotions. PMID:26778987

  20. Vaginal bleeding between periods

    MedlinePlus

    ... periods; Intermenstrual bleeding; Spotting; Metrorrhagia Images Female reproductive anatomy Bleeding between periods Uterus References Bulun SE. The physiology and pathology of the female reproductive axis. In: ...

  1. Voltage-gated Na+ channel activation induces both action potentials in utricular hair cells and brain-derived neurotrophic factor release in the rat utricle during a restricted period of development

    PubMed Central

    Chabbert, Christian; Mechaly, Ilana; Sieso, Victor; Giraud, Pierre; Brugeaud, Aurore; Lehouelleur, Jacques; Couraud, François; Valmier, Jean; Sans, Alain

    2003-01-01

    The mammalian utricular sensory receptors are commonly believed to be non-spiking cells with electrical activity limited to graded membrane potential changes. Here we provide evidence that during the first post-natal week, the sensory hair cells of the rat utricle express a tetrodotoxin (TTX)-sensitive voltage-gated Na+ current that displays most of the biophysical and pharmacological characteristics of neuronal Na+ current. Single-cell RT-PCR reveals that several α-subunit isoforms of the Na+ channels are co-expressed within a single hair cell, with a major expression of Nav1.2 and Nav1.6 subunits. In neonatal hair cells, 30 % of the Na+ channels are available for activation at the resting potential. Depolarizing current injections in the range of the transduction currents are able to trigger TTX-sensitive action potentials. We also provide evidence of a TTX-sensitive activity-dependent brain-derived neurotrophic factor (BDNF) release by early post-natal utricle explants. Developmental analysis shows that Na+ currents decrease dramatically from post-natal day 0 (P0) to P8 and become almost undetectable at P21. Concomitantly, depolarizing stimuli fail to induce both action potential and BDNF release at P20. The present findings reveal that vestibular hair cells express neuronal-like TTX-sensitive Na+ channels able to generate Na+-driven action potentials only during the early post-natal period of development. During the same period an activity-dependent BDNF secretion by utricular explants has been demonstrated. This could be an important mechanism involved in vestibular sensory system differentiation and synaptogenesis. PMID:12963806

  2. Long-lasting changes in morphine-induced locomotor sensitization and tolerance in Long-Evans mother rats as a result of periodic postpartum separation from the litter: a novel model of increased vulnerability to drug abuse?

    PubMed

    Kalinichev, Mikhail; Easterling, Keith W; Holtzman, Stephen G

    2003-02-01

    Daily postpartum separations from the litter produce enduring changes in anxiety and sensitivity to the antinociceptive effects of morphine in Long-Evans dams. We tested whether postpartum experience alters sensitivity to the effects of morphine on locomotor activity. Dams were tested 4-6 weeks after their pups were weaned, and had one of the following backgrounds: daily separation from the litter on postpartum days 2-14 for either 3 h (prolonged separation-LS) or 15 min (brief separation-BS), or no separation (nonhandled control-NH). After 2 consecutive days (B1-2) of baseline activity measurements, subjects were tested daily after s.c. injections of either morphine (10 mg/kg) or saline for 7 days and again on day 10. Beginning 5 days later, saline and 1.0-10 mg/kg of morphine were tested in all dams. On B1, LS and BS dams habituated slower than NH controls, yielding higher horizontal counts. LS dams failed to habituate across baseline days and were more active than other dams on B2. Sensitization, a progressive increase in horizontal activity, was more rapid and robust in LS and BS dams compared to NH animals. LS was the only group that developed tolerance to morphine-induced decreases in vertical activity. In LS dams with the history of morphine treatment, injection of saline resulted in higher horizontal activity and center time compared to saline-treated counterparts, indicative of conditioning. Among animals with a history of saline treatment, LS dams were more sensitive to morphine challenges than BS and NH dams. As a result of the robust and long-lasting increases in the ability of morphine to induce behavioral sensitization in litter-separated dams, periodic postpartum separation may represent a new animal model of increased vulnerability to substance abuse.

  3. Your First Period

    MedlinePlus

    ... adult’s. Starting your menstrual period is one of these changes. What is a menstrual period? When puberty begins, your brain signals your body to produce hormones . Some of these hormones prepare your body each month for a ...

  4. The Periodic Pyramid

    ERIC Educational Resources Information Center

    Hennigan, Jennifer N.; Grubbs, W. Tandy

    2013-01-01

    The chemical elements present in the modern periodic table are arranged in terms of atomic numbers and chemical periodicity. Periodicity arises from quantum mechanical limitations on how many electrons can occupy various shells and subshells of an atom. The shell model of the atom predicts that a maximum of 2, 8, 18, and 32 electrons can occupy…

  5. Community College Periodicals.

    ERIC Educational Resources Information Center

    Pederson, Eldor O.

    Drawing from an examination of community college periodicals, their availability and characteristics, the academic affiliations of contributing authors, and the topics of their articles, this paper discusses the minor role which community college periodicals appear to play. A list of 35 periodicals dealing primary with community college education…

  6. The Periodic Pyramid

    ERIC Educational Resources Information Center

    Hennigan, Jennifer N.; Grubbs, W. Tandy

    2013-01-01

    The chemical elements present in the modern periodic table are arranged in terms of atomic numbers and chemical periodicity. Periodicity arises from quantum mechanical limitations on how many electrons can occupy various shells and subshells of an atom. The shell model of the atom predicts that a maximum of 2, 8, 18, and 32 electrons can occupy…

  7. Short-term periodic consumption of multiprobiotic from childhood improves insulin sensitivity, prevents development of non-alcoholic fatty liver disease and adiposity in adult rats with glutamate-induced obesity

    PubMed Central

    2014-01-01

    insulin sensitivity and prevention of non-alcoholic fatty liver (NAFLD) development. Conclusions These results have shown that periodic treatment with multiprobiotic prevents the MSG-induced obesity and NAFLD development. PMID:25030027

  8. Periodic chiral structures

    NASA Technical Reports Server (NTRS)

    Jaggard, Dwight L.; Engheta, Nader; Pelet, Philippe; Liu, John C.; Kowarz, Marek W.; Kim, Yunjin

    1989-01-01

    The electromagnetic properties of a structure that is both chiral and periodic are investigated using coupled-mode equations. The periodicity is described by a sinusoidal perturbation of the permittivity, permeability, and chiral admittance. The coupled-mode equations are derived from physical considerations and used to examine bandgap structure and reflected and transmitted fields. Chirality is observed predominantly in transmission, whereas periodicity is present in both reflection and transmission.

  9. Exogenous corticosterone induces the expression of the clock protein, PERIOD2, in the oval nucleus of the bed nucleus of the stria terminalis and the central nucleus of the amygdala of adrenalectomized and intact rats.

    PubMed

    Segall, Lauren A; Amir, Shimon

    2010-10-01

    The cyclical expression of the clock protein PERIOD2 (PER2) in select regions of the limbic forebrain is contingent upon the rhythmic secretion of the adrenal glucocorticoid, corticosterone. Daily rhythmic PER2 expression in the oval nucleus of the bed nucleus of the stria terminalis (BNSTov) and the central nucleus of the amygdala (CEA) is abolished with the removal of the adrenal glands but restored with rhythmic hormone replacement via the drinking water at a time corresponding to the endogenous peak of circulating glucocorticoids. Here, we investigated the effects of serial or acute systemic injections of corticosterone on the expression of PER2 in the BNSTov and CEA of both adrenalectomized (ADX) and intact rats. We sought to determine whether there is a temporal window of corticosterone sensitivity by delivering the hormone at a time corresponding to trough levels of circulating glucocorticoids, at lights on. We found that daily morning injections of corticosterone induced PER2 expression in the BNSTov and CEA of ADX rats, with levels peaking 1 h after injection. In intact rats, daily morning injections significantly upregulated the expression of PER2 in the BNSTov and CEA 1 h after injection and dampened the evening peak, while a single injection abolished the rhythm of PER2 expression in the CEA but had no effect on PER2 in the BNSTov. Our findings suggest that despite the potential masking effect of signals from the light-entrained master clock, daytime chronic and acute corticosterone administration can alter the rhythmic expression of PER2 in the BNSTov and CEA, and that the response is region-specific and dependent on the duration of treatment.

  10. Periodic Solutions of Spatially Periodic Hamiltonian Systems

    DTIC Science & Technology

    1989-07-10

    Theorem 0.2 generalizes Theorem 1.5 of Rabinowitz in [201. 3 Equation (0.1), under spatially periodic assumptions has been studied by several au...n x n symmetric matrix, H satisfying (HO), (H1) and (H2), and f = (0, fq) satisfying (fM), (fl) and (f2), Rabinowitz in [201 showed the existence of... Rabinowitz [17]. We consider a functional I : E x M ) R of class C’, where E is a Hilbert space and M is a compact manifold. Assuming that I satisfies a

  11. Periodic syndromes of childhood.

    PubMed

    Arav-Boger, R; Spirer, Z

    1997-01-01

    Periodic syndromes of childhood comprise a large group of disorders that require long-term follow-up to be diagnosed. Several disorders have fixed rhythmicity and are therefore identified more easily. Other disorders are usually diagnosed after a prolonged follow-up and exclusion of other more common childhood diseases. In general, most of the periodic fever syndromes have a benign prognosis, and their symptomatology tends to improve in the long term. Periodic syndromes without fever or chronic pain syndromes constitute not only a diagnostic dilemma but also a therapeutic challenge. A general diagnostic approach to the periodic syndromes is outlined in Figure 1.

  12. The Living Periodic Table

    ERIC Educational Resources Information Center

    Nahlik, Mary Schrodt

    2005-01-01

    To help make the abstract world of chemistry more concrete eighth-grade students, the author has them create a living periodic table that can be displayed in the classroom or hallway. This display includes information about the elements arranged in the traditional periodic table format, but also includes visual real-world representations of the…

  13. The Living Periodic Table

    ERIC Educational Resources Information Center

    Nahlik, Mary Schrodt

    2005-01-01

    To help make the abstract world of chemistry more concrete eighth-grade students, the author has them create a living periodic table that can be displayed in the classroom or hallway. This display includes information about the elements arranged in the traditional periodic table format, but also includes visual real-world representations of the…

  14. Latent Period of Relaxation.

    PubMed

    Kobayashi, M; Irisawa, H

    1961-10-27

    The latent period of relaxation of molluscan myocardium due to anodal current is much longer than that of contraction. Although the rate and the grade of relaxation are intimately related to both the stimulus condition and the muscle tension, the latent period of relaxation remains constant, except when the temperature of the bathing fluid is changed.

  15. Multidimensional period doubling structures.

    PubMed

    Lee, Jeong Yup; Flom, Dvir; Ben-Abraham, Shelomo I

    2016-05-01

    This paper develops the formalism necessary to generalize the period doubling sequence to arbitrary dimension by straightforward extension of the substitution and recursion rules. It is shown that the period doubling structures of arbitrary dimension are pure point diffractive. The symmetries of the structures are pointed out.

  16. Haemocytic periodicity and periodic disorders: Periodic neutropenia, thrombocytopenia, lymphocytosis and anaemia

    PubMed Central

    Reimann, Hobart A.

    1971-01-01

    Evidence has accumulated of rhythmic numerical oscillation of each of the blood cells either independently or in combinations. The cyclic changes originate in the marrow of some normal persons and animals without causing illness, and can be induced experimentally. In more than 100 reported instances, periodic oscillations of various cells were accompanied by respective episodes of the disorders named in the title. The disorders may be transitory but usually recur throughout life and occasionally are fatal. All resist therapy. Features in common suggest an interrelationship of the haemal disorders and other disparate heritable periodic diseases. Theoretically, the rhythms are regulated by ubiquitous, inherent, intracellular bioclocks controlled hypothalamically or neurohumorally in relation to a feedback mechanism. Reactions to long cycles are of greater clinical importance than disturbances arising from the circadian rhythm. PMID:4397784

  17. Genealogy of periodic trajectories

    SciTech Connect

    de Adguiar, M.A.M.; Maldta, C.P.; de Passos, E.J.V.

    1986-05-20

    The periodic solutions of non-integrable classical Hamiltonian systems with two degrees of freedom are numerically investigated. Curves of periodic families are given in plots of energy vs. period. Results are presented for this Hamiltonian: H = 1/2(p/sub x//sup 2/ + p/sub y//sup 2/) + 1/2 x/sup 2/ + 3/2 y/sup 2/ - x/sup 2/y + 1/12 x/sup 4/. Properties of the families of curves are pointed out. (LEW)

  18. Periodically poled silicon

    NASA Astrophysics Data System (ADS)

    Hon, Nick K.; Tsia, Kevin K.; Solli, Daniel R.; Jalali, Bahram

    2009-03-01

    We propose a new class of photonic devices based on periodic stress fields in silicon that enable second-order nonlinearity as well as quasi-phase matching. Periodically poled silicon (PePSi) adds the periodic poling capability to silicon photonics and allows the excellent crystal quality and advanced manufacturing capabilities of silicon to be harnessed for devices based on second-order nonlinear effects. As an example of the utility of the PePSi technology, we present simulations showing that midwave infrared radiation can be efficiently generated through difference frequency generation from near-infrared with a conversion efficiency of 50%.

  19. Canakinumab (ACZ885, a fully human IgG1 anti-IL-1β mAb) induces sustained remission in pediatric patients with cryopyrin-associated periodic syndrome (CAPS)

    PubMed Central

    2011-01-01

    Introduction Cryopyrin-associated periodic syndrome (CAPS) represents a spectrum of three auto-inflammatory syndromes, familial cold auto-inflammatory syndrome (FCAS), Muckle-Wells syndrome (MWS), and neonatal-onset multisystem inflammatory disease/chronic infantile neurological cutaneous and articular syndrome (NOMID/CINCA) with etiology linked to mutations in the NLRP3 gene resulting in elevated interleukin-1β (IL-1β) release. CAPS is a rare hereditary auto-inflammatory disease, which may start early in childhood and requires a life-long treatment. Canakinumab, a fully human anti-IL-1β antibody, produces sustained selective inhibition of IL-1β. This study was conducted to assess the efficacy, safety, and pharmacokinetics of canakinumab in the treatment of pediatric CAPS patients. Methods Seven pediatric patients (five children and two adolescents) with CAPS were enrolled in a phase II, open-label study of canakinumab in patients with CAPS. Canakinumab was administered at a dose of 2 mg/kg subcutaneously (s.c.) (for patients with body weight ≤ 40 kg) or 150 mg s.c. (for patients with body weight > 40 kg) with re-dosing upon each relapse. The primary efficacy variable was time to relapse following achievement of a complete response (defined as a global assessment of no or minimal disease activity and no or minimal rash and values for serum C-reactive protein (CRP) and/or serum amyloid A (SAA) within the normal range, < 10 mg/L). Results All patients achieved a complete response within seven days after the first dose of canakinumab and responses were reinduced on retreatment following relapse. Improvements in symptoms were evident within 24 hours after the first dose, according to physician assessments. The estimated median time to relapse was 49 days (95% CI 29 to 68) in children who received a dose of 2 mg/kg. Canakinumab was well tolerated. One serious adverse event, vertigo, was reported, but resolved during treatment. Conclusions Canakinumab, 2 mg/kg or

  20. Setting the Periodic Table.

    ERIC Educational Resources Information Center

    Saturnelli, Annette

    1985-01-01

    Examines problems resulting from different forms of the periodic table, indicating that New York State schools use a form reflecting the International Union of Pure and Applied Chemistry's 1984 recommendations. Other formats used and reasons for standardization are discussed. (DH)

  1. The Periodic Table CD.

    ERIC Educational Resources Information Center

    Banks, Alton J.; Holmes, Jon L.

    1995-01-01

    Describes the characteristics of the digitized version of The Periodic Table Videodisc. Provides details about the organization of information and access to the data via Macintosh and Windows computers. (DDR)

  2. The Periodic Table CD.

    ERIC Educational Resources Information Center

    Banks, Alton J.; Holmes, Jon L.

    1995-01-01

    Describes the characteristics of the digitized version of The Periodic Table Videodisc. Provides details about the organization of information and access to the data via Macintosh and Windows computers. (DDR)

  3. Setting the Periodic Table.

    ERIC Educational Resources Information Center

    Saturnelli, Annette

    1985-01-01

    Examines problems resulting from different forms of the periodic table, indicating that New York State schools use a form reflecting the International Union of Pure and Applied Chemistry's 1984 recommendations. Other formats used and reasons for standardization are discussed. (DH)

  4. Effects of periodic discharges

    NASA Technical Reports Server (NTRS)

    Ford, F. E.

    1977-01-01

    Periodic capacity checks are assessed as well as the effects of periodic discharges on the cycle life and the performance of cells during the cycle life. Topics discussed include the effect of the amount of electrolyte on cell capacity at 35 C; battery design for spacecraft; electrolyte starvation theory; battery separator degradation; negative electrode stability; voltage regulation; operating temperatures; and integration of reconditioning systems using microprocessors.

  5. Isoprenaline and canine cardiac refractory periods.

    PubMed

    Lhoste, F; Giudicelli, J F; Boissier, J R

    1976-09-01

    Atrioventricular refractory periods and their modifications induced by variable doses of sioprenaline have been investigated in dogs. Premature atrial stimuli (St2) were applied at variable intervals following regular stimuli (St1) which ensured atrial pacing. Atrial (AERP), nodoventricular (NERP) and global (GERP) effective refractory periods, as well as the global functional refractory period (GFRP) were determined before, during and after infusion of the drug. In low doses, isoprenaline did not significantly alter these various parameters. This confirms its lack of dromotropic effect on the healthy heart. In contrast, high doses of the drug significantly reduced the refractory periods, probably by simple correction of the negative dromotropic effects resulting from overstimulation. Also when the infusion was stopped, marked but reversible conduction depression was observed. It would appear that this reflects 'exhaustion' of cell metabolism induced by the drug.

  6. Hyperthyroid hypokalemic periodic paralysis

    PubMed Central

    Neki, N.S.

    2016-01-01

    Hyperthyroid periodic paralysis (HPP) is a rare life threatening complication of hyperthyroidism commonly occurring in young Asian males but sporadically found in other races. It is characterised by hypokalemia and acute onset paraparesis with prevalence of one in one hundred thousand (1 in 100000). The symptoms resolve promptly with potassium supplementation. Nonselective beta blockers like propranol can also be used to ameliorate and prevent subsequent paralytic attack. We report a case of 22 year old male presenting with hyperthyroid periodic paralysis (HPP) having very low serum potassium level. PMID:27648066

  7. "Ictal" lateralized periodic discharges.

    PubMed

    Sen-Gupta, Indranil; Schuele, Stephan U; Macken, Micheal P; Kwasny, Mary J; Gerard, Elizabeth E

    2014-07-01

    Whether lateralized periodic discharges (LPDs) represent ictal or interictal phenomena, and even the circumstances in which they may represent one or the other, remains highly controversial. Lateralized periodic discharges are, however, widely accepted as being ictal when they are time-locked to clinically apparent symptoms. We sought to investigate the characteristics of "ictal" lateralized periodic discharges (ILPDs) defined by time-locked clinical symptoms in order to explore the utility of using this definition to dichotomize LPDs into "ictal" and "nonictal" categories. Our archive of all continuous EEG (cEEG) reports of adult inpatients undergoing prolonged EEG monitoring for nonelective indications between 2007 and 2011 was searched to identify all reports describing LPDs. Lateralized periodic discharges were considered ILPDs when they were reported as being consistently time-locked to clinical symptoms; LPDs lacking a clear time-locked correlate were considered to be "nonictal" lateralized periodic discharges (NILPDs). Patient charts and available neuroimaging studies were also reviewed. Neurophysiologic localization of LPDs, imaging findings, presence of seizures, discharge outcomes, and other demographic factors were compared between patients with ILPDs and those with NILPDs. p-Values were adjusted for false discovery rate (FDR). One thousand four hundred fifty-two patients underwent cEEG monitoring at our institution between 2007 and 2011. Lateralized periodic discharges were reported in 90 patients, 10 of whom met criteria for ILPDs. Nine of the patients with ILPDs demonstrated motor symptoms, and the remaining patient experienced stereotyped sensory symptoms. Ictal lateralized periodic discharges had significantly increased odds for involving central head regions (odds ratio [OR]=11; 95% confidence interval [CI]=2.16-62.6; p=0.018, FDR adjusted), with a trend towards higher proportion of lesions involving the primary sensorimotor cortex (p=0.09, FDR

  8. Oscillations following periodic reinforcement.

    PubMed

    Monteiro, Tiago; Machado, Armando

    2009-06-01

    Three experiments examined behavior in extinction following periodic reinforcement. During the first phase of Experiment 1, four groups of pigeons were exposed to fixed interval (FI 16s or FI 48s) or variable interval (VI 16s or VI 48s) reinforcement schedules. Next, during the second phase, each session started with reinforcement trials and ended with an extinction segment. Experiment 2 was similar except that the extinction segment was considerably longer. Experiment 3 replaced the FI schedules with a peak procedure, with FI trials interspersed with non-food peak interval (PI) trials that were four times longer. One group of pigeons was exposed to FI 20s PI 80s trials, and another to FI 40s PI 160s trials. Results showed that, during the extinction segment, most pigeons trained with FI schedules, but not with VI schedules, displayed pause-peck oscillations with a period close to, but slightly greater than the FI parameter. These oscillations did not start immediately after the onset of extinction. Comparing the oscillations from Experiments 1 and 2 suggested that the alternation of reconditioning and re-extinction increases the reliability and earlier onset of the oscillations. In Experiment 3 the pigeons exhibited well-defined pause-peck cycles since the onset of extinction. These cycles had periods close to twice the value of the FI and lasted for long intervals of time. We discuss some hypotheses concerning the processes underlying behavioral oscillations following periodic reinforcement.

  9. Scheduling: Seven Period Day

    ERIC Educational Resources Information Center

    Williamson, Ronald

    2010-01-01

    Driven by stable or declining financial resources many school districts are considering the costs and benefits of a seven-period day. While there is limited evidence that any particular scheduling model has a greater impact on student learning than any other, it is clear that the school schedule is a tool that can significantly impact teacher…

  10. Periodically structured plasmonic waveguides

    NASA Astrophysics Data System (ADS)

    Saj, W. M.; Foteinopoulou, S.; Kafesaki, M.; Soukoulis, C. M.; Economou, E. N.

    2008-04-01

    We study surface plasmon polariton (SPP) guiding structures, which are a modification of the Metal-Insulator-Metal (MIM) waveguide. The designs are constructed by introducing a periodic modulation in a MIM waveguide, with a glass core and silver claddings. This periodic modulation is created either by causing periodic indentations in the silver slabs encompassing the glass core, or by increasing the glass spacer material in certain periodic locations. Our objective is to achieve long range sub-wavelength waveguiding with vast dispersion engineering capabilities. We employ the Finite Difference Time Domain Method (FDTD) with the Auxiliary Differential Equation method (ADE) for the calculation of the dispersion relation of the guided modes, as well as the real time propagation suggests that the guiding mechnism in the examined structures is based on the electromagnetic (EM) couping between the slit plasmon modes. These - depending on the design - exist in the grooves between the silver plates or in the larger areas of the glass core spacer. Put it different, the guiding mechanism in the examined SPP waveguide designs is analogous to the EM energy transfer along metallic nanoparticle chains.

  11. A Modern Periodic Table.

    ERIC Educational Resources Information Center

    Herrenden-Harker, B. D.

    1997-01-01

    Presents a modern Periodic Table based on the electron distribution in the outermost shell and the order of filling of the sublevels within the shells. Enables a student to read off directly the electronic configuration of the element and the order in which filling occurs. (JRH)

  12. Periodic Table of Students.

    ERIC Educational Resources Information Center

    Johnson, Mike

    1998-01-01

    Presents an exercise in which an eighth-grade science teacher decorated the classroom with a periodic table of students. Student photographs were arranged according to similarities into vertical columns. Students were each assigned an atomic number according to their placement in the table. The table is then used to teach students about…

  13. A Modern Periodic Table.

    ERIC Educational Resources Information Center

    Herrenden-Harker, B. D.

    1997-01-01

    Presents a modern Periodic Table based on the electron distribution in the outermost shell and the order of filling of the sublevels within the shells. Enables a student to read off directly the electronic configuration of the element and the order in which filling occurs. (JRH)

  14. Periodic Table of Students.

    ERIC Educational Resources Information Center

    Johnson, Mike

    1998-01-01

    Presents an exercise in which an eighth-grade science teacher decorated the classroom with a periodic table of students. Student photographs were arranged according to similarities into vertical columns. Students were each assigned an atomic number according to their placement in the table. The table is then used to teach students about…

  15. Astrophysical implications of periodicity

    NASA Technical Reports Server (NTRS)

    Muller, Richard A.

    1988-01-01

    Two remarkable discoveries of the last decade have profound implications for astrophysics and for geophysics. These are the discovery by Alvarez et al., that certain mass extinctions are caused by the impact on the earth of a large asteroid or comet, and the discovery by Raup and Sepkoski that such extinctions are periodic, with a cycle time of 26 to 30 million years. The validity of both of these discoveries is assumed and the implications are examined. Most of the phenomena described depend not on periodicity, but just on the weaker assumption that the impacts on the earth take place primarily in showers. Proposed explanations for the periodicity include galactic oscillations, the Planet X model, and the possibility of Nemesis, a solar companion star. These hypotheses are critically examined. Results of the search for the solar companion are reported. The Deccan flood basalts of India have been proposed as the impact site for the Cretaceous impact, but this hypotheisis is in contradiction with the conclusion of Courtillot et al., that the magma flow began during a period of normal magnetic field. A possible resolution of this contradiction is proposed.

  16. Getting Your Period

    MedlinePlus

    ... for a woman to have a baby. During sexual intercourse, the egg can get fertilized by a male’s sperm and then attach to the lining of the uterus ( endometrium ) and grow into a baby. ( Read more about reproduction. ) Does your period come each month? top Menstrual ...

  17. The Jovian period in the Sun?

    NASA Astrophysics Data System (ADS)

    Kotov, V. A.

    2015-09-01

    The 41-year measurements of the Doppler effect of the photosphere performed at the Crimean Astrophysical Observatory, discovered two periods of global oscillations of the Sun: 9600.606(12) s and 9597.929(15) s. Their beat period, 398.4(2.9) d, well agrees with a synodic orbital period of Jupiter, PJ = 398.9 d, raising a new problem for solar physics, cosmogony and cosmology. A hypothesis is advanced that the PJ beating of the Sun is induced by gravitation of Jupiter, revolving in a privileged reference system "the Sun - the Earth".

  18. Periodicity of extinction: A 1988 update

    NASA Technical Reports Server (NTRS)

    Sepkowski, J. John, Jr.

    1988-01-01

    The hypothesis that events of mass extinction recur periodically at approximately 26 my intervals is an empirical claim based on analysis of data from the fossil record. The hypothesis has become closely linked with catastrophism because several events in the periodic series are associated with evidence of extraterrestrial impacts, and terrestrial forcing mechanisms with long, periodic recurrences are not easily conceived. Astronomical mechanisms that have been hypothesized include undetected solar companions and solar oscillation about the galactic plane, which induce comet showers and result in impacts on Earth at regular intervals. Because these mechanisms are speculative, they have been the subject of considerable controversy, as has the hypothesis of periodicity of extinction. In response to criticisms and uncertainties, a data base was developed on times of extinction of marine animal genera. A time series is given and analyzed with 49 sample points for the per-genus extinction rate from the Late Permian to the Recent. An unexpected pattern in the data is the uniformity of magnitude of many of the periodic extinction events. Observations suggest that the sequence of extinction events might be the result of two sets of mechanisms: a periodic forcing that normally induces only moderate amounts of extinction, and independent incidents or catastrophes that, when coincident with the periodic forcing, amplify its signal and produce major-mass extinctions.

  19. Water repellent periodic mesoporous organosilicas.

    PubMed

    Wang, Wendong; Grozea, Daniel; Kohli, Sandeep; Perovic, Douglas D; Ozin, Geoffrey A

    2011-02-22

    This paper demonstrates for the first time thermally induced gradual hydrophobization, monitored quantitatively by ellipsometric porosimetry, of four prototypical periodic mesoporous organosilicas (PMOs) that are tailored through materials chemistry for use as low-dielectric-constant (low k) materials in microprocessors. Theoretical aspects of this quantification are briefly discussed. A comparison of structural, mechanical, dielectric, and hydrophobic properties of ethane, methane, ethene, and 3-ring PMOs is made. Particularly, ethane, methane, and 3-ring PMOs show impressive water repellency at post-treatment temperatures as low as 350 °C, with corresponding Young's modulus values greater than 10 GPa and k values smaller than 2, a figure of merit that satisfies the technological requirements of future generation microchips.

  20. Thyrotoxic periodic paralysis

    SciTech Connect

    Ferreiro, J.E.; Arguelles, D.J.; Rams, H. Jr.

    1986-01-01

    A case of thyrotoxic periodic paralysis is reported in a Hispanic man with an unusual recurrence six weeks after radioactive iodine treatment. Thyrotoxic periodic paralysis has now been well characterized in the literature: it occurs primarily in Orientals with an overwhelming male preponderance and a higher association of specific HLA antigens. Clinical manifestations include onset after high carbohydrate ingestion or heavy exertion, with progressive symmetric weakness leading to flaccid paralysis of the extremities and other muscle groups, lasting several hours. If hypokalemia is present, potassium administration may help abort the attack. Although propranolol can be efficacious in preventing further episodes, the only definitive treatment is establishing a euthyroid state. The pathophysiology is still controversial, but reflects altered potassium and calcium dynamics as well as certain morphologic characteristics within the muscle unit itself.

  1. Periodic minimal surfaces

    NASA Astrophysics Data System (ADS)

    Mackay, Alan L.

    1985-04-01

    A minimal surface is one for which, like a soap film with the same pressure on each side, the mean curvature is zero and, thus, is one where the two principal curvatures are equal and opposite at every point. For every closed circuit in the surface, the area is a minimum. Schwarz1 and Neovius2 showed that elements of such surfaces could be put together to give surfaces periodic in three dimensions. These periodic minimal surfaces are geometrical invariants, as are the regular polyhedra, but the former are curved. Minimal surfaces are appropriate for the description of various structures where internal surfaces are prominent and seek to adopt a minimum area or a zero mean curvature subject to their topology; thus they merit more complete numerical characterization. There seem to be at least 18 such surfaces3, with various symmetries and topologies, related to the crystallographic space groups. Recently, glyceryl mono-oleate (GMO) was shown by Longley and McIntosh4 to take the shape of the F-surface. The structure postulated is shown here to be in good agreement with an analysis of the fundamental geometry of periodic minimal surfaces.

  2. Evaluation of the antihistamine effects of olopatadine and levocetirizine during a 24-h period: a double-blind, randomized, cross-over, placebo-controlled comparison in skin responses induced by histamine iontophoresis.

    PubMed

    Takeo, Tomohiro; Kasugai, Chikatoshi; Tanaka, Rui; Ando, Takashi; Ogawa, Akina; Akita, Yoichi; Watanabe, Daisuke

    2013-12-01

    The antihistamine effects of olopatadine and levocetirizine, in standard-dose application described in their information (5 mg twice a day for olopatadine; 5 mg once daily for levocetirizine), were examined from 11.5 to 24 h after application. The test was designed in a double-blind, randomized, cross-over, placebo-controlled study of 12 healthy volunteers on histamine-induced flare and wheal response using an iontophoresis technique. The suppressive effect of olopatadine on the wheals induced by a 0.1-mA histamine iontophoresis lasted for 24 h after dosing. Both drugs inhibited flare induced by histamine iontophoresis almost completely until 24 h after the first administration. Suppression of the 0.2-mA-induced wheal response by levocetirizine, taken once daily, decreased with time, although 0.1-mA-induced flare was almost completely suppressed by the drug. Olopatadine completely suppressed even the wheal response induced by a 0.2-mA histamine iontophoresis. Compared with the placebo, the two drugs significantly suppressed the subjective itching assessed by visual analog scale at all intervals. There were no significant differences in subjective drowsiness and objective cognitive function between drug- and placebo-treated subjects. These results demonstrate that olopatadine seems to be more potent than levocetirizine when administrated in a standard dose. In conclusion, mild to moderate urticaria could be controlled by standard application as described in their information. On the other hand, severe urticaria could be managed by a standard application of olopatadine, but levocetirizine may need an additional dose to control severe urticaria. © 2013 Japanese Dermatological Association.

  3. The postanesthetic period. Complications.

    PubMed

    Malamed, S F

    1987-01-01

    Postanesthetic complications can occur even in the best of circumstances. Proper preparation of the staff, aggressive monitoring of the recovering patient, and early recognition and management of the complications are essential if the outcome is to be successful. In reviewing postanesthetic complications, two factors are present in the overwhelming majority of situations--hypoxia and hypercarbia--often the direct result of inadequate monitoring during the postanesthetic period. The anesthetic procedure is not over once the anesthetic agents are discontinued. The skillful anesthetist is aware of the possibilities of postoperative complications and prevents problems by employing enhanced monitoring techniques during the recovery phase.

  4. Hypokalemic periodic paralysis

    PubMed Central

    Abbas, Haider; Kothari, Nikhil; Bogra, Jaishri

    2012-01-01

    Hypokalemic periodic paralysis is a rare genetic disorder characterized by recurrent attacks of skeletal muscle weakness with associated hypokalemia which is precipitated by stress, cold, carbohydrate load, infection, glucose infusion, hypothermia, metabolic alkalosis, anesthesia, and steroids. We encountered one such incidence of prolonged recovery after general anesthesia, which on further evaluation revealed a case of hypokalemic paralysis. The key to successful management of such a patient was vigilant pre-operative evaluation, perioperative monitoring, and aggressive treatment of hypokalemia when it occurs. PMID:23833504

  5. Multifunctional periodic cellular metals.

    PubMed

    Wadley, Haydn N G

    2006-01-15

    Periodic cellular metals with honeycomb and corrugated topologies are widely used for the cores of light weight sandwich panel structures. Honeycombs have closed cell pores and are well suited for thermal protection while also providing efficient load support. Corrugated core structures provide less efficient and highly anisotropic load support, but enable cross flow heat exchange opportunities because their pores are continuous in one direction. Recent advances in topology design and fabrication have led to the emergence of lattice truss structures with open cell structures. These three classes of periodic cellular metals can now be fabricated from a wide variety of structural alloys. Many topologies are found to provide adequate stiffness and strength for structural load support when configured as the cores of sandwich panels. Sandwich panels with core relative densities of 2-10% and cell sizes in the millimetre range are being assessed for use as multifunctional structures. The open, three-dimensional interconnected pore networks of lattice truss topologies provide opportunities for simultaneously supporting high stresses while also enabling cross flow heat exchange. These highly compressible structures also provide opportunities for the mitigation of high intensity dynamic loads created by impacts and shock waves in air or water. By filling the voids with polymers and hard ceramics, these structures have also been found to offer significant resistance to penetration by projectiles.

  6. Periodic truss structures

    NASA Astrophysics Data System (ADS)

    Zok, Frank W.; Latture, Ryan M.; Begley, Matthew R.

    2016-11-01

    Despite the recognition of the enormous potential of periodic trusses for use in a broad range of technologies, there are no widely-accepted descriptors of their structure. The terminology has been based loosely either on geometry of polyhedra or of point lattices: neither of which, on its own, has an appropriate structure to fully define periodic trusses. The present article lays out a system for classification of truss structure types. The system employs concepts from crystallography and geometry to describe nodal locations and connectivity of struts. Through a series of illustrative examples of progressively increasing complexity, a rational taxonomy of truss structure is developed. Its conceptual evolution begins with elementary cubic trusses, increasing in complexity with non-cubic and compound trusses as well as supertrusses, and, finally, with complex trusses. The conventions and terminology adopted to define truss structure yield concise yet unambiguous descriptions of structure types and of specific (finite) trusses. The utility of the taxonomy is demonstrated by bringing into alignment a disparate set of ad hoc and incomplete truss designations previously employed in a broad range of science and engineering fields. Additionally, the merits of a particular compound truss (comprising two interpenetrating elementary trusses) is shown to be superior to the octet truss for applications requiring high stiffness and elastic isotropy. By systematically stepping through and analyzing the finite number of structure types identified through the present classification system, optimal structures for prescribed mechanical and functional requirements are expected to be ascertained in an expeditious manner.

  7. Investigation on Periodically Surface-Corrugated Long-Period Gratings Inscribed on Photonic Crystal Fibers.

    PubMed

    Han, Young-Geun

    2017-12-01

    Transmission characteristics of periodically surface-corrugated long-period gratings (LPGs) inscribed on photonic crystal fibers (PCFs) using a wet-etching technique were experimentally investigated. A conventional wet method was implemented to periodically engrave the silica cladding region of the PCFs resulting in the periodic surface corrugation in the PCF. After applying the external strain to the PCF with the periodic surface micro-ridges, periodic modulation of refractive index based on the photoelastic effect is induced resulting in the formation of the PCF-based LPG. Increasing the applied strain successfully improves the extinction ratio of the resonant peak of the PCF-based LPG without the resonant wavelength shift. We also measured the transmission characteristics of the PCF-based LPG with variations in temperature and ambient index.

  8. Periodized Nutrition for Athletes.

    PubMed

    Jeukendrup, Asker E

    2017-03-01

    It is becoming increasingly clear that adaptations, initiated by exercise, can be amplified or reduced by nutrition. Various methods have been discussed to optimize training adaptations and some of these methods have been subject to extensive study. To date, most methods have focused on skeletal muscle, but it is important to note that training effects also include adaptations in other tissues (e.g., brain, vasculature), improvements in the absorptive capacity of the intestine, increases in tolerance to dehydration, and other effects that have received less attention in the literature. The purpose of this review is to define the concept of periodized nutrition (also referred to as nutritional training) and summarize the wide variety of methods available to athletes. The reader is referred to several other recent review articles that have discussed aspects of periodized nutrition in much more detail with primarily a focus on adaptations in the muscle. The purpose of this review is not to discuss the literature in great detail but to clearly define the concept and to give a complete overview of the methods available, with an emphasis on adaptations that are not in the muscle. Whilst there is good evidence for some methods, other proposed methods are mere theories that remain to be tested. 'Periodized nutrition' refers to the strategic combined use of exercise training and nutrition, or nutrition only, with the overall aim to obtain adaptations that support exercise performance. The term nutritional training is sometimes used to describe the same methods and these terms can be used interchangeably. In this review, an overview is given of some of the most common methods of periodized nutrition including 'training low' and 'training high', and training with low- and high-carbohydrate availability, respectively. 'Training low' in particular has received considerable attention and several variations of 'train low' have been proposed. 'Training-low' studies have generally

  9. Buckling of periodic structures

    NASA Technical Reports Server (NTRS)

    Anderson, M. S.

    1980-01-01

    Equations are developed for the buckling of a general lattice structure that has repetitive geometry. Equilibrium at a typical node is expressed using finite element techniques, and the only assumption is that the response is periodic. By basing the stiffness matrix on the exact solution of the beam column equation, accurate results are obtained for complex buckling behavior that would require a very large system of equations using conventional techniques. The present method requires the eigenvalues of only a 6x6 determinant. The results are used to study the buckling of isogrid cylinders, three-element truss columns and polygonal rings. Details of the analysis including expressions for all terms in the governing stability determinant are given.

  10. When Periodicities Enforce Aperiodicity

    NASA Astrophysics Data System (ADS)

    Bédaride, Nicolas; Fernique, Thomas

    2015-05-01

    Non-periodic tilings and local rules are commonly used to model the long range aperiodic order of quasicrystals and the finite-range energetic interactions that stabilize them. This paper focuses on planar rhombus tilings, which are tilings of the Euclidean plane, which can be seen as an approximation of a real plane embedded in a higher dimensional space. Our main result is a characterization of the existence of local rules for such tilings when the embedding space is four-dimensional. The proof is an interplay of algebra and geometry that makes use of the rational dependencies between the coordinates of the embedded plane. We also apply this result to some cases in a higher dimensional embedding space, notably tilings with n-fold rotational symmetry.

  11. Periodically driven holographic superconductor

    NASA Astrophysics Data System (ADS)

    Li, Wei-Jia; Tian, Yu; Zhang, Hongbao

    2013-07-01

    As a first step towards our holographic investigation of the far-from-equilibrium physics of periodically driven systems at strong coupling, we explore the real time dynamics of holographic superconductor driven by a monochromatically alternating electric field with various frequencies. As a result, our holographic superconductor is driven to the final oscillating state, where the condensate is suppressed and the oscillation frequency is controlled by twice of the driving frequency. In particular, in the large frequency limit, the three distinct channels towards the final steady state are found, namely under damped to superconducting phase, over damped to superconducting and normal phase, which can be captured essentially by the low lying spectrum of quasi-normal modes in the time averaged approximation, reminiscent of the effective field theory perspective.

  12. Model Valid Prediction Period

    NASA Astrophysics Data System (ADS)

    Chu, P. C.

    2002-12-01

    A new concept, valid prediction period (VPP), is presented here to evaluate model predictability. VPP is defined as the time period when the prediction error first exceeds a pre-determined criterion (i.e., the tolerance level). It depends not only on the instantaneous error growth, but also on the noise level, the initial error, and tolerance level. The model predictability skill is then represented by a single scalar, VPP. The longer the VPP, the higher the model predictability skill is. A theoretical framework on the base of the backward Fokker-Planck equation is developed to determine the probability density function (pdf) of VPP. Verification of a Gulf of Mexico nowcast/forecast model is used as an example to demonstrate the usefulness of VPP. Power law scaling is found in the mean square error of displacement between drifting buoy and model trajectories (both at 50 m depth). The pdf of VPP is asymmetric with a long and broad tail on the higher value side, which suggests long-term predictability. The calculations demonstrate that the long-term (extreme long such as 50-60 day) predictability is not an "outlier" and shares the same statistical properties as the short-term predictions. References Chu P. C., L. M. Ivanov, and C.W. Fan, Backward Fokker-Plank equation for determining model predictability with unknown initial error distribution. J. Geophys. Res., in press, 2002. Chu P.C., L.M.Ivanov, T.M. Margolina, and O.V.Melnichenko, 2002b: On probabilistic stability of an atmospheric model to various amplitude perturbations. J. Atmos. Sci., in press Chu P.C., L.M. Ivanov, L. Kantha, O.V. Melnichenko and Y.A. Poberezhny, 2002c: The long-term correlations and power decay law in model prediction skill. Geophys. Res. Let., in press.

  13. [Childhood periodic syndromes].

    PubMed

    Cuvellier, J-C; Lépine, A

    2010-01-01

    This review focuses on the so-called "periodic syndromes of childhood that are precursors to migraine", as included in the Second Edition of the International Classification of Headache Disorders. Three periodic syndromes of childhood are included in the Second Edition of the International Classification of Headache Disorders: abdominal migraine, cyclic vomiting syndrome and benign paroxysmal vertigo, and a fourth, benign paroxysmal torticollis is presented in the Appendix. The key clinical features of this group of disorders are the episodic pattern and intervals of complete health. Episodes of benign paroxysmal torticollis begin between 2 and 8 months of age. Attacks are characterized by an abnormal inclination and/or rotation of the head to one side, due to cervical dystonia. They usually resolve by 5 years. Benign paroxysmal vertigo presents as sudden attacks of vertigo, accompanied by inability to stand without support, and lasting seconds to minutes. Age at onset is between 2 and 4 years, and the symptoms disappear by the age of 5. Cyclic vomiting syndrome is characterized in young infants and children by repeated stereotyped episodes of pernicious vomiting, at times to the point of dehydration, and impacting quality of life. Mean age of onset is 5 years. Abdominal migraine remains a controversial issue and presents in childhood with repeated stereotyped episodes of unexplained abdominal pain, nausea and vomiting occurring in the absence of headache. Mean age of onset is 7 years. Both cyclic vomiting syndrome and abdominal migraine are noted for the absence of pathognomonic clinical features but also for the large number of other conditions to be considered in their differential diagnoses. Diagnostic criteria, such as those of the Second Edition of the International Classification of Headache Disorders and the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition, have made diagnostic approach and management easier. Their diagnosis

  14. Progression of DNA damage induced by a glyphosate-based herbicide in fish (Anguilla anguilla) upon exposure and post-exposure periods--insights into the mechanisms of genotoxicity and DNA repair.

    PubMed

    Marques, Ana; Guilherme, Sofia; Gaivão, Isabel; Santos, Maria Ana; Pacheco, Mário

    2014-11-01

    Roundup® is a glyphosate-based herbicide widely used with both agricultural and non-agricultural purposes, which has been demonstrated to represent a risk to non-target aquatic organisms, namely fish. Among the described effects to fish, genotoxicity has been pointed out as one of the most hazardous. However, the genotoxic mechanisms of Roundup® as well as the involvement of the oxidative DNA damage repair system are not entirely understood. Hence, this work aimed to improve the knowledge on the progression of DNA damage upon short-term exposure (3 days) and post-exposure (1-14 days) periods in association with DNA repair processes in Anguilla anguilla exposed to Roundup® (58 and 116 μg L⁻¹). DNA damage in hepatic cells was evaluated by the comet assay improved with the DNA-lesion specific endonucleases FPG and EndoIII. In order to evaluate the oxidative DNA damage repair ability, an in vitro base excision repair (BER) assay was performed, testing hepatic subcellular extracts. Besides the confirmation of the genotoxic potential of this herbicide, oxidative damage was implicit as an important mechanism of genetic damage, which showed to be transient, since DNA integrity returned to the control levels on the first day after cessation of exposure. An increased capacity to repair oxidative DNA damage emerging in the post-exposure period revealed to be a crucial pathway for the A. anguilla recovery; nevertheless, DNA repair machinery showed to be susceptible to inhibitory actions during the exposure period, disclosing another facet of the risk associated with the tested agrochemical. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Periodically kicked hard oscillators.

    PubMed

    Cecchi, G. A.; Gonzalez, D. L.; Magnasco, M. O.; Mindlin, G. B.; Piro, O.; Santillan, A. J.

    1993-01-01

    A model of a hard oscillator with analytic solution is presented. Its behavior under periodic kicking, for which a closed form stroboscopic map can be obtained, is studied. It is shown that the general structure of such an oscillator includes four distinct regions; the outer two regions correspond to very small or very large amplitude of the external force and match the corresponding regions in soft oscillators (invertible degree one and degree zero circle maps, respectively). There are two new regions for intermediate amplitude of the forcing. Region 3 corresponds to moderate high forcing, and is intrinsic to hard oscillators; it is characterized by discontinuous circle maps with a flat segment. Region 2 (low moderate forcing) has a certain resemblance to a similar region in soft oscillators (noninvertible degree one circle maps); however, the limit set of the dynamics in this region is not a circle, but a branched manifold, obtained as the tangent union of a circle and an interval; the topological structure of this object is generated by the finite size of the repelling set, and is therefore also intrinsic to hard oscillators.

  16. Maternal Caloric Restriction Implemented during the Preconceptional and Pregnancy Period Alters Hypothalamic and Hippocampal Endocannabinoid Levels at Birth and Induces Overweight and Increased Adiposity at Adulthood in Male Rat Offspring.

    PubMed

    Ramírez-López, María Teresa; Vázquez, Mariam; Bindila, Laura; Lomazzo, Ermelinda; Hofmann, Clementine; Blanco, Rosarío Noemí; Alén, Francisco; Antón, María; Decara, Juan; Arco, Rocío; Ouro, Daniel; Orio, Laura; Suárez, Juan; Lutz, Beat; Gómez de Heras, Raquel; Rodríguez de Fonseca, Fernando

    2016-01-01

    Exposure to inadequate nutritional conditions in critical windows of development has been associated to disturbances on metabolism and behavior in the offspring later in life. The role of the endocannabinoid system, a known regulator of energy expenditure and adaptive behaviors, in the modulation of these processes is unknown. In the present study, we investigated the impact of exposing rat dams to diet restriction (20% less calories than standard diet) during pre-gestational and gestational periods on: (a) neonatal outcomes; (b) endocannabinoid content in hypothalamus, hippocampus and olfactory bulb at birth; (c) metabolism-related parameters; and (d) behavior in adult male offspring. We found that calorie-restricted dams tended to have a reduced litter size, although the offspring showed normal weight at birth. Pups from calorie-restricted dams also exhibited a strong decrease in the levels of anandamide (AEA), 2-arachidonoylglycerol (2-AG), arachidonic acid (AA) and palmitoylethanolamide (PEA) in the hypothalamus at birth. Additionally, pups from diet-restricted dams displayed reduced levels of AEA in the hippocampus without significant differences in the olfactory bulb. Moreover, offspring exhibited increased weight gain, body weight and adiposity in adulthood as well as increased anxiety-related responses. We propose that endocannabinoid signaling is altered by a maternal caloric restriction implemented during the preconceptional and pregnancy periods, which might lead to modifications of the hypothalamic and hippocampal circuits, potentially contributing to the long-term effects found in the adult offspring.

  17. Maternal Caloric Restriction Implemented during the Preconceptional and Pregnancy Period Alters Hypothalamic and Hippocampal Endocannabinoid Levels at Birth and Induces Overweight and Increased Adiposity at Adulthood in Male Rat Offspring

    PubMed Central

    Ramírez-López, María Teresa; Vázquez, Mariam; Bindila, Laura; Lomazzo, Ermelinda; Hofmann, Clementine; Blanco, Rosarío Noemí; Alén, Francisco; Antón, María; Decara, Juan; Arco, Rocío; Ouro, Daniel; Orio, Laura; Suárez, Juan; Lutz, Beat; Gómez de Heras, Raquel; Rodríguez de Fonseca, Fernando

    2016-01-01

    Exposure to inadequate nutritional conditions in critical windows of development has been associated to disturbances on metabolism and behavior in the offspring later in life. The role of the endocannabinoid system, a known regulator of energy expenditure and adaptive behaviors, in the modulation of these processes is unknown. In the present study, we investigated the impact of exposing rat dams to diet restriction (20% less calories than standard diet) during pre-gestational and gestational periods on: (a) neonatal outcomes; (b) endocannabinoid content in hypothalamus, hippocampus and olfactory bulb at birth; (c) metabolism-related parameters; and (d) behavior in adult male offspring. We found that calorie-restricted dams tended to have a reduced litter size, although the offspring showed normal weight at birth. Pups from calorie-restricted dams also exhibited a strong decrease in the levels of anandamide (AEA), 2-arachidonoylglycerol (2-AG), arachidonic acid (AA) and palmitoylethanolamide (PEA) in the hypothalamus at birth. Additionally, pups from diet-restricted dams displayed reduced levels of AEA in the hippocampus without significant differences in the olfactory bulb. Moreover, offspring exhibited increased weight gain, body weight and adiposity in adulthood as well as increased anxiety-related responses. We propose that endocannabinoid signaling is altered by a maternal caloric restriction implemented during the preconceptional and pregnancy periods, which might lead to modifications of the hypothalamic and hippocampal circuits, potentially contributing to the long-term effects found in the adult offspring. PMID:27847471

  18. Epigenetics in the perioperative period

    PubMed Central

    Lirk, P; Fiegl, H; Weber, N C; Hollmann, M W

    2015-01-01

    The perioperative period is characterized by profound changes in the body's homoeostatic processes. This review seeks to address whether epigenetic mechanisms may influence an individual's reaction to surgery and anaesthesia. Evidence from animal and human studies suggests that epigenetic mechanisms can explain many facets of susceptibility to acute and chronic pain, making them potential therapeutic targets. Modern pain management is still based upon opiates, and both the developmental expression of opioid receptors and opioid-induced hyperalgesia have been linked to epigenetic mechanisms. In general, opiates seem to increase global DNA methylation levels. This is in contrast to local anaesthetics, which have been ascribed a global demethylating effect. Even though no direct investigations have been carried out, the potential influence of epigenetics on the inflammatory response that follows surgery seems a promising area for research. There is a considerable body of evidence that supports the involvement of epigenetics in the complex process of wound healing. Epigenetics is an important emerging research topic in perioperative medicine, with a huge potential to positively influence patient outcome. PMID:25073649

  19. Optically controlled periodical chain of quantum rings

    NASA Astrophysics Data System (ADS)

    Hasan, M.; Iorsh, I. V.; Kibis, O. V.; Shelykh, I. A.

    2016-03-01

    We demonstrated theoretically that a circularly polarized electromagnetic field substantially modifies electronic properties of a periodical chain of quantum rings. Particularly, the field opens band gaps in the electron energy spectrum of the chain, generates edge electron currents, and induces the Fano-like features in the electron transport through the finite chain. These effects create physical prerequisites for the development of optically controlled nanodevices based on a set of coupled quantum rings.

  20. Formation of periodic structures on glass with laser irradiation

    NASA Astrophysics Data System (ADS)

    Peng, Ying Zi; An, Cheng Wu; Wu, Dong Jiang; Hong, Ming Hui; Lu, Yong Feng; Chong, Tow Chong

    2003-07-01

    Regular and tidy periodic structures hae been directly induced on glasses using a CW CO2 laser beam with linear polarization. It is experimentally shown that precise periodic structures with the period of several microns can be formed by means of well-set laser parameters. The orientation of the periodic structures formed is the same as that of the laser polarization no matter what the scanning direction is. The occurrence of periodic structures is very sensitive to laser power level and scanning velocity. To obtain appropriate periodic patterns, a combined condition of laser energy and scanning velocity must be satisfied. The period, width and height of the structures are dependent on processing parameters. An interesting phenomenon is that the period decreases with increasing scanning velocity. Permanent relieves with periods, widths and heights varied with the laser parameters are also studied.

  1. Persistence in periodic and almost periodic Lotka-Volterra systems.

    PubMed

    Gopalsamy, K

    1984-01-01

    It is shown that a strongly self-regulating (or resource limited) Lotka-Volterra population system can "persist" in a periodic or almost periodic environment if and only if the system tracks the environmental variations.

  2. Instability of time-periodic flows

    NASA Technical Reports Server (NTRS)

    Hall, P.

    1985-01-01

    The instabilities of some spatially and/or time-periodic flows are discussed, in particular, flows with curved streamlines which can support Taylor-Gortler vortices are described in detail. The simplest flow where this type of instability can occur is that due to the torsional oscillations of an infinitely long circular cylinder. For more complicated spatially varying time-periodic flows, a similar type of instability can occur and is spatially localized near the most unstable positions. When nonlinear effects are considered it is found that the instability modifies the steady streaming boundary layer induced by the oscillatory motion. It is shown that a rapidly rotating cylinder in a uniform flow is susceptible to a related type of instability; the appropriate stability equations are shown to be identical to those which govern the instability of a boussinesq fluid of Prandtl number unity heated time periodically from below.

  3. 76 FR 8325 - Periodic Reporting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-14

    ... data for Presort First-Class Mail, and End-to-End Periodicals. Request at 1. The Request includes... Standard Mail, Outside County Periodicals, non-retail Media Mail, Library Mail, Bound Printed Matter...

  4. The redoubtable ecological periodic table

    EPA Science Inventory

    Ecological periodic tables are repositories of reliable information on quantitative, predictably recurring (periodic) habitat–community patterns and their uncertainty, scaling and transferability. Their reliability derives from their grounding in sound ecological principle...

  5. The redoubtable ecological periodic table

    EPA Science Inventory

    Ecological periodic tables are repositories of reliable information on quantitative, predictably recurring (periodic) habitat–community patterns and their uncertainty, scaling and transferability. Their reliability derives from their grounding in sound ecological principle...

  6. Doubly Resonant Optical Periodic Structure

    PubMed Central

    Alagappan, G.; Png, C. E.

    2016-01-01

    Periodic structures are well known in various branches of physics for their ability to provide a stopband. In this article, using optical periodic structures we showed that, when a second periodicity – very closed to the original periodicity is introduced, large number of states appears in the stopband corresponding to the first periodicity. In the limit where the two periods matches, we have a continuum of states, and the original stopband completely disappears. This intriguing phenomena is uncovered by noticing that, regardless of the proximities of the two periodicities, there is an array of spatial points where the dielectric functions corresponding to the two periodicities interfere destructively. These spatial points mimic photonic atoms by satisfying the standards equations of quantum harmonic oscillators, and exhibit lossless, atom-like dispersions. PMID:26853945

  7. Doubly Resonant Optical Periodic Structure.

    PubMed

    Alagappan, G; Png, C E

    2016-02-08

    Periodic structures are well known in various branches of physics for their ability to provide a stopband. In this article, using optical periodic structures we showed that, when a second periodicity--very closed to the original periodicity is introduced, large number of states appears in the stopband corresponding to the first periodicity. In the limit where the two periods matches, we have a continuum of states, and the original stopband completely disappears. This intriguing phenomena is uncovered by noticing that, regardless of the proximities of the two periodicities, there is an array of spatial points where the dielectric functions corresponding to the two periodicities interfere destructively. These spatial points mimic photonic atoms by satisfying the standards equations of quantum harmonic oscillators, and exhibit lossless, atom-like dispersions.

  8. Metamaterial properties of periodic laminates

    NASA Astrophysics Data System (ADS)

    Srivastava, Ankit

    2016-11-01

    In this paper we show that a 1-D phononic crystal (laminate) can exhibit metamaterial wave phenomena which are traditionally associated with 2- and 3-D crystals. Moreover, due to the absence of a length scale in 2 of its dimensions, it can outperform higher dimensional crystals on some measures. This includes allowing only negative refraction over large frequency ranges and serving as a near-omnidirectional high-pass filter up to a large frequency value. First we provide a theoretical discussion on the salient characteristics of the dispersion relation of a laminate and formulate the solution of an interface problem by the application of the normal mode decomposition technique. We present a methodology with which to induce a pure negative refraction in the laminate. As a corollary to our approach of negative refraction, we show how the laminate can be used to steer beams over large angles for small changes in the incident angles (beam steering). Furthermore, we clarify how the transmitted modes in the laminate can be switched on and off by varying the angle of the incident wave by a small amount. Finally, we show that the laminate can be used as a remarkably efficient high-pass frequency filter. An appropriately designed laminate will reflect all plane waves from quasi-static to a large frequency, incident at it from all angles except for a small set of near-normal incidences. This will be true even if the homogeneous medium is impedance matched with the laminate. Due to the similarities between SH waves and electromagnetic (EM) waves it is expected that some or all of these results may also apply to EM waves in a layered periodic dielectric.

  9. New Galactic Double Periodic Variables

    NASA Astrophysics Data System (ADS)

    Mennickent, R. E.; Rosales, J.

    2014-10-01

    We discovered two new Double Periodic Variables in the ASAS catalogue of variable stars, viz., V495 Cen and V4142 Sgr. Other 3 candidates for Double Periodic Variables were found. All systems have relatively long orbital periods. We present improved ephemerides and disentangled light curves.

  10. 75 FR 1301 - Periodic Reporting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-11

    ... 39 CFR Part 3050 Periodic Reporting AGENCY: Postal Regulatory Commission. ACTION: Proposed rule... rulemaking proceeding to consider changes in the analytical methods approved for use in periodic reporting.\\1... Docket No. RM2009-10, Order on Analytical Principles Used in Periodic Reporting (Proposals Three through...

  11. 76 FR 297 - Periodic Reporting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-04

    ... 39 CFR Part 3050 Periodic Reporting AGENCY: Postal Regulatory Commission. ACTION: Notice of proposed... a proposed change in certain analytical methods used in periodic reporting. This action responds to... proceeding to consider changes in the analytical methods approved for use in periodic reporting.\\1\\ Four...

  12. Fractional-period excitations in continuum periodic systems

    SciTech Connect

    Nistazakis, H. E.; Frantzeskakis, D. J.; Porter, Mason A.; Kevrekidis, P. G.; Nicolin, A.; Chin, J. K.

    2006-12-15

    We investigate the generation of fractional-period states in continuum periodic systems. As an example, we consider a Bose-Einstein condensate confined in an optical-lattice potential. We show that when the potential is turned on nonadiabatically, the system explores a number of transient states whose periodicity is a fraction of that of the lattice. We illustrate the origin of fractional-period states analytically by treating them as resonant states of a parametrically forced Duffing oscillator and discuss their transient nature and potential observability.

  13. From Periodic Properties to a Periodic Table Arrangement

    ERIC Educational Resources Information Center

    Besalú, Emili

    2013-01-01

    A periodic table is constructed from the consideration of periodic properties and the application of the principal components analysis technique. This procedure is useful for objects classification and data reduction and has been used in the field of chemistry for many applications, such as lanthanides, molecules, or conformers classification.…

  14. From Periodic Properties to a Periodic Table Arrangement

    ERIC Educational Resources Information Center

    Besalú, Emili

    2013-01-01

    A periodic table is constructed from the consideration of periodic properties and the application of the principal components analysis technique. This procedure is useful for objects classification and data reduction and has been used in the field of chemistry for many applications, such as lanthanides, molecules, or conformers classification.…

  15. 24 CFR 203.266 - Period covered by periodic MIP.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... HOUSING AND URBAN DEVELOPMENT MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND OTHER... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Period covered by periodic MIP. 203.266 Section 203.266 Housing and Urban Development Regulations Relating to Housing and...

  16. 24 CFR 203.266 - Period covered by periodic MIP.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... HOUSING AND URBAN DEVELOPMENT MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND OTHER... 24 Housing and Urban Development 2 2013-04-01 2013-04-01 false Period covered by periodic MIP. 203.266 Section 203.266 Housing and Urban Development Regulations Relating to Housing and...

  17. 24 CFR 203.266 - Period covered by periodic MIP.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... HOUSING AND URBAN DEVELOPMENT MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND OTHER... 24 Housing and Urban Development 2 2011-04-01 2011-04-01 false Period covered by periodic MIP. 203.266 Section 203.266 Housing and Urban Development Regulations Relating to Housing and...

  18. 24 CFR 203.266 - Period covered by periodic MIP.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... HOUSING AND URBAN DEVELOPMENT MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND OTHER... 24 Housing and Urban Development 2 2012-04-01 2012-04-01 false Period covered by periodic MIP. 203.266 Section 203.266 Housing and Urban Development Regulations Relating to Housing and...

  19. 24 CFR 203.266 - Period covered by periodic MIP.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... HOUSING AND URBAN DEVELOPMENT MORTGAGE AND LOAN INSURANCE PROGRAMS UNDER NATIONAL HOUSING ACT AND OTHER... 24 Housing and Urban Development 2 2014-04-01 2014-04-01 false Period covered by periodic MIP. 203.266 Section 203.266 Housing and Urban Development Regulations Relating to Housing and...

  20. On the Period-Amplitude and Amplitude-Period Relationships

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.; Hathaway, David H.

    2008-01-01

    Examined are Period-Amplitude and Amplitude-Period relationships based on the cyclic behavior of the 12-month moving averages of monthly mean sunspot numbers for cycles 0.23, both in terms of Fisher's exact tests for 2x2 contingency tables and linear regression analyses. Concerning the Period-Amplitude relationship (same cycle), because cycle 23's maximum amplitude is known to be 120.8, the inferred regressions (90-percent prediction intervals) suggest that its period will be 131 +/- 24 months (using all cycles) or 131 +/- 18 months (ignoring cycles 2 and 4, which have the extremes of period, 108 and 164 months, respectively). Because cycle 23 has already persisted for 142 months (May 1996 through February 2008), based on the latter prediction, it should end before September 2008. Concerning the Amplitude-Period relationship (following cycle maximum amplitude versus preceding cycle period), because cycle 23's period is known to be at least 142 months, the inferred regressions (90-percent prediction intervals) suggest that cycle 24's maximum amplitude will be about less than or equal to 96.1 +/- 55.0 (using all cycle pairs) or less than or equal to 91.0 +/- 36.7 (ignoring statistical outlier cycle pairs). Hence, cycle 24's maximum amplitude is expected to be less than 151, perhaps even less than 128, unless cycle pair 23/24 proves to be a statistical outlier.

  1. Changing Periods of ST Puppis

    NASA Astrophysics Data System (ADS)

    Walker, S.; Butterworth, N.; Pearce, A.

    2015-12-01

    ST Puppis is a reasonably bright W Virginis variable star, a Type 2 Cepheid with a record of substantial and erratic period changes—21 during the interval 1900 to 1985 with a range of magnitude from 17.4 to 19.2. It was observed as part of Variable Stars South's Cepheid project by Butterworth in 2014 and 2015 using DSLR photometry in BGR passbands and visually by Pearce in 2015. The known period changes are shown graphically and doubtful ones examined and discarded if necessary. With its period and amplitude with a frequently changing period it is a suitable and worthwhile object for visual observing.

  2. Assessing periodicity of periodic leg movements during sleep.

    PubMed

    Rummel, Christian; Gast, Heidemarie; Schindler, Kaspar; Müller, Markus; Amor, Frédérique; Hess, Christian W; Mathis, Johannes

    2010-01-01

    Periodic leg movements (PLM) during sleep consist of involuntary periodic movements of the lower extremities. The debated functional relevance of PLM during sleep is based on correlation of clinical parameters with the PLM index (PLMI). However, periodicity in movements may not be reflected best by the PLMI. Here, an approach novel to the field of sleep research is used to reveal intrinsic periodicity in inter movement intervals (IMI) in patients with PLM. Three patient groups of 10 patients showing PLM with OSA (group 1), PLM without OSA or RLS (group 2) and PLM with RLS (group 3) are considered. Applying the "unfolding" procedure, a method developed in statistical physics, enhances or even reveals intrinsic periodicity of PLM. The degree of periodicity of PLM is assessed by fitting one-parameter distributions to the unfolded IMI distributions. Finally, it is investigated whether the shape of the IMI distributions allows to separate patients into different groups. Despite applying the unfolding procedure, periodicity is neither homogeneous within nor considerably different between the three clinically defined groups. Data-driven clustering reveals more homogeneous and better separated clusters. However, they consist of patients with heterogeneous demographic data and comorbidities, including RLS and OSA. The unfolding procedure may be necessary to enhance or reveal periodicity. Thus this method is proposed as a pre-processing step before analyzing PLM statistically. Data-driven clustering yields much more reasonable results when applied to the unfolded IMI distributions than to the original data. Despite this effort no correlation between the degree of periodicity and demographic data or comorbidities is found. However, there are indications that the nature of the periodicity might be determined by long-range interactions between LM of patients with PLM and OSA.

  3. Stochastic theory of log-periodic patterns

    NASA Astrophysics Data System (ADS)

    Canessa, Enrique

    2000-12-01

    We introduce an analytical model based on birth-death clustering processes to help in understanding the empirical log-periodic corrections to power law scaling and the finite-time singularity as reported in several domains including rupture, earthquakes, world population and financial systems. In our stochastic theory log-periodicities are a consequence of transient clusters induced by an entropy-like term that may reflect the amount of co-operative information carried by the state of a large system of different species. The clustering completion rates for the system are assumed to be given by a simple linear death process. The singularity at t0 is derived in terms of birth-death clustering coefficients.

  4. 75 FR 7426 - Periodic Reporting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-19

    ... 39 CFR Part 3050 Periodic Reporting AGENCY: Postal Regulatory Commission. ACTION: Advance notice of...-789-6820 or stephen.sharfman@prc.gov . SUPPLEMENTARY INFORMATION: Table of Contents I. Background II... approved for use in periodic reporting.\\1\\ The Postal Service labels its proposal ``Proposal One'' because...