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Responsivity
Selected AbstractsChronic Naltrexone Treatment and Ethanol Responsivity in Outbred RatsALCOHOLISM, Issue 2 2010Katherine G. Hill Background:, Acute naltrexone treatment in rats produces significant alterations in ethanol palatability (increase in the aversiveness of the solution) and ethanol consumption during tests of restricted access (decrease in consumption). The effects of chronic naltrexone exposure, accomplished by implantation of osmotic mini-pumps, were examined in the present study. Methods:, Rats were surgically implanted with intraoral fistulae for taste reactivity testing. The animals were given 2 bottles (distilled water and 10% ethanol, v/v) for 3, 2-week phases: Pre-Drug, Drug, and Post-Drug. After the Pre-Drug phase, rats were assigned to groups (counterbalanced based on ethanol intake) and implanted with a mini-pump containing saline, 7.5 mg/kg/d naltrexone, or 15 mg/kg/d naltrexone. The pumps were removed 2 weeks later. During each 2-week phase, taste reactivity tests with 10% ethanol were conducted at 1, 7, and 14 days (a total of 9 reactivity tests). Results:, The 7.5 mg/kg/d dose produced only minor effects on 10% ethanol reactivity and consumption during the Drug phase. The 15 mg/kg/d naltrexone dose generally shifted taste reactivity responding to 10% ethanol in a negative direction and produced a transient decrease in ethanol consumption. The 15 mg/kg/d group significantly increased ethanol consumption beyond the level of consumption by the Saline group when the pumps were removed, although the increase was delayed 48 hours. By the end of the Post-Drug period, this naltrexone group returned to control levels of ethanol consumption. Conclusions:, Chronic naltrexone treatment at 15 mg/kg/d significantly decreased the palatability of a 10% ethanol solution, an effect seen even after drug withdrawal. Naltrexone had a minor effect on ethanol consumption during treatment but did decrease overall levels of fluid consumption. The significant increase in ethanol consumption postdrug by the high-dose naltrexone group, presumably due to receptor up-regulation during treatment, is important and understanding this effect and developing means of overcoming it within a clinical practice would be useful goals. [source] Photodynamic Actinometry Using Microspheres: Concept, Development and Responsivity ,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2004Stuart K. Bisland ABSTRACT Photodynamic therapy (PDT) relies on three main ingredients, oxygen, light and photoactivating compounds, although the PDT response is definitively contingent on the site and level of reactive oxygen species (ROS) generation. This study describes the development of a novel, fluorescent-based actinometer microsphere system as a means of discerning spatially resolved dosimetry of total fluence and ROS production. Providing a high resolution, localized, in situ measurement of fluence and ROS generation is critical for developing in vivo PDT protocols. Alginate-poly- l -lysine-alginate microspheres were produced using ionotropic gelation of sodium alginate droplets, ranging from 80 to 200 ,m in diameter, incorporating two dyes, ADS680WS (ADS) and Rhodophyta-phycoerythrin (RPE), attached to the spheres' inside and outside layers, respectively. To test the responsivity and dynamic range of RPE for ROS detection, the production of ROS was initiated either chemically using increasing concentrations of potassium perchromate or photochemically using aluminum tetrasulphonated phthalocyanine. The generation of singlet oxygen was confirmed by phosphorescence at 1270 nm. The resulting photodegradation and decrease in fluorescence of RPE was found to correlate with increased perchromate or PDT treatment fluence, respectively. This effect was independent of pH (6.5,8) and could be inhibited using sodium azide. RPE was not susceptible to photobleaching with light alone (670 nm; 150 Jcm,2). ADS, which absorbs light between 600 and 750 nm, showed a direct correlation between radiant exposure (670 nm; 0,100 Jcm,2) and diminished fluorescence. Photobleaching was independent of irradiance (10,40 mW cm,2). We propose that actinometer microspheres may provide a means for obtaining high spatial resolution information regarding delivered PDT dose within model systems during investigational PDT development and dosimetric information for clinical extracorporeal PDT as in the case of ex vivo bone marrow purging. [source] High-Performance Langmuir,Blodgett Monolayer Transistors with High Responsivity,ANGEWANDTE CHEMIE, Issue 36 2010Yang Cao Molekulare Feldeffekttransistoren mit Ladungsträgermobilitäten wie Standardtransistoren (bis 0.04,cm2,V,1,s,1), hohen An/Aus-Stromverhältnissen (>106) und hoher Ansprechempfindlichkeit entstehen durch Kombination von Langmuir-Blodgett-Techniken mit Mikro/Nanofertigung aus einheitlichen selbstorganisierten Kupferphthalocyanin(CuPc)-Halbleiter-Monoschichten und einzelnen Graphenschichten als planare Kontakte. [source] ZnO-based photodetector with internal photocurrent gainPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2010L. A. Kosyachenko Abstract The photoresponsive structures prepared by magnetron sputtering of ZnO on p-Si substrates followed by vacuum evaporation of semitransparent Ni film on ZnO surface are investigated. The obtained Ni/n-ZnO/p-Si structures show high sensitivity that sharply increases with increase in applied voltage. Under a bias voltage of 5,V, the responsivities at ,,=,390,nm and ,,=,850,nm were equal to 210 and 110,A/W, which correspond to quantum efficiencies of 655 and 165, respectively. It is assumed that the observed strong response is attributed to internal gain in the Ni/n-ZnO/p-Si phototransistor structure containing Ni/n-ZnO Schottky contact as the emitter junction and n-ZnO/p-Si heterostructure as the collector junction. The response time of the device is ,10,7,s. Alternative mechanisms of photocurrent multiplication in such structures are also discussed. [source] Differential development of infants at risk for psychopathology: the moderating role of early maternal responsivityDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 5 2001Manfred Laucht PhD The development of behaviour problems in infants born with biological risk (low birthweight) and psychosocial risk (psychosocially disadvantaged family) was studied in a sample of 347 children (171 males, 176 females) at the ages of 2, 4:6, and 8 years. In the search for factors that moderate the effects of early risks, the role of early responsive caregiving was examined. Results indicate that infants at psychosocial risk exhibited both more externalizing and internalizing problems across ages than infants not at psychosocial risk, while no overall differences were apparent between normal-and low-birthweight groups. With one exception, no interactions between biological and psychosocial risk factors emerged, suggesting that their simultaneous effect is largely additive. Maternal responsivity was found to moderate the effects of low birthweight on hyperkinetic and internalizing problems as well as to influence the consequences of family disadvantage on total problems. These findings stress the importance of early parenting in the behavioural development of at-risk children. [source] Behavioral response to methylphenidate challenge: Influence of early life parental careDEVELOPMENTAL PSYCHOBIOLOGY, Issue 5 2009Veronika Engert Abstract Rat studies have shown that pups subjected to suboptimal rearing conditions exhibited permanently dysregulated dopamine activity and altered behavioral responses to dopamine stimulation. In humans, heightened stress-induced mesoaccumbens dopamine release in adults reporting low maternal care experience has been shown. We explored the relationship between quality of parental care and behavioral responsivity to reward and 20,mg of the dopamine agonist methylphenidate (MPH). Forty-three male university students accomplished a monetarily rewarded card-sorting task in a placebo controlled between-subjects study design. In participants scoring above the cut-off score for high parental care as assessed by the Parental Bonding Inventory, MPH decreased performance accuracy in the reward condition of the task. Contrarily, reward-induced performance accuracy of low care participants was enhanced with MPH. Activity measures in response to reward and MPH were uninfluenced by parental care. This is the first human study to reveal that the behavioral MPH response interacts with early life parental care experience. © 2009 Wiley Periodicals, Inc. Dev Psychobiol 51: 408,416, 2009. [source] Perceived quality of maternal care in childhood and structure and function of mothers' brainDEVELOPMENTAL SCIENCE, Issue 4 2010Pilyoung Kim Animal studies indicate that early maternal care has long-term effects on brain areas related to social attachment and parenting, whereas neglectful mothering is linked with heightened stress reactivity in the hippocampus across the lifespan. The present study explores the possibility, using magnetic resonance imaging, that perceived quality of maternal care in childhood is associated with brain structure and functional responses to salient infant stimuli among human mothers in the first postpartum month. Mothers who reported higher maternal care in childhood showed larger grey matter volumes in the superior and middle frontal gyri, orbital gyrus, superior temporal gyrus and fusiform gyrus. In response to infant cries, these mothers exhibited higher activations in the middle frontal gyrus, superior temporal gyrus and fusiform gyrus, whereas mothers reporting lower maternal care showed increased hippocampal activations. These findings suggest that maternal care in childhood may be associated with anatomy and functions in brain regions implicated in appropriate responsivity to infant stimuli in human mothers. [source] Sex differences in schizophrenia, a review of the literatureACTA PSYCHIATRICA SCANDINAVICA, Issue 401 2000Dr. Alice Leung M.D. Objective: To comprehensively and critically review the literature on gender differences in schizophrenia. Method: An initial search of MEDLINE abstracts (1966,1999) was conducted using the terms sex or gender and schizophrenia, followed by systematic search of all relevant articles. Results: Males have consistently an earlier onset, poorer premorbid functioning and different premorbid behavioral predictors. Males show more negative symptoms and cognitive deficits, with greater structural brain and neurophysiological abnormalities. Females display more affective symptoms, auditory hallucinations and persecutory delusions with more rapid and greater responsivity to antipsychotics in the pre-menopausal period but increased side effects. Course of illness is more favorable in females in the short- and middle-term, with less smoking and substance abuse. Families of males are more critical, and expressed emotion has a greater negative impact on males. There are no clear sex differences in family history, obstetric complications, minor physical anomalies and neurological soft signs. Conclusion: This review supports the presence of significant differences between schizophrenic males and females arising from the interplay of sex hormones, neurodevelopmental and psychosocial sex differences. [source] Patterns of change in withdrawal symptoms, desire to smoke, reward motivation and response inhibition across 3 months of smoking abstinenceADDICTION, Issue 5 2009Lynne Dawkins ABSTRACT Aims We have demonstrated previously that acute smoking abstinence is associated with lowered reward motivation and impaired response inhibition. This prospective study explores whether these impairments, along with withdrawal-related symptoms, recover over 3 months of sustained abstinence. Design Participants completed a 12-hour abstinent baseline assessment and were then allocated randomly to quit unaided or continue smoking. All were re-tested after 7 days, 1 month and 3 months. Successful quitters' scores were compared with those of continuing smokers, who were tested after ad libitum smoking. Setting Goldsmiths, University of London. Participants A total of 33 smokers who maintained abstinence to 3 months, and 31 continuing smokers. Measurements Indices demonstrated previously in this cohort of smokers to be sensitive to the effect of nicotine versus acute abstinence: reward motivation [Snaith,Hamilton pleasure scale (SHAPS), Card Arranging Reward Responsivity Objective Test (CARROT), Stroop], tasks of response inhibition [anti-saccade task; Continuous Performance Task (CPT)], clinical indices of mood [Hospital Anxiety and Depression Scale (HADS)], withdrawal symptoms [Mood and Physical Symptoms Scale (MPSS)] and desire to smoke. Findings SHAPS anhedonia and reward responsivity (CARROT) showed significant improvement and plateaued after a month of abstinence, not differing from the scores of continuing smokers tested in a satiated state. Mood, other withdrawal symptoms and desire to smoke all declined from acute abstinence to 1 month of cessation and were equivalent to, or lower than, the levels reported by continuing, satiated smokers. Neither group showed a change in CPT errors over time while continuing smokers, but not abstainers, showed improved accuracy on the anti-saccade task at 3 months. Conclusion Appetitive processes and related affective states appear to improve in smokers who remain nicotine-free for 3 months, whereas response inhibition does not. Although in need of replication, the results suggest tentatively that poor inhibitory control may constitute a long-term risk factor for relapse and could be a target for intervention. [source] Prenatal stress reduces postnatal neurogenesis in rats selectively bred for high, but not low, anxiety: possible key role of placental 11,-hydroxysteroid dehydrogenase type 2EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 1 2009P. J. Lucassen Abstract Prenatal stress (PS) produces persistent abnormalities in anxiety-related behaviors, stress responsivity, susceptibility to psychopathology and hippocampal changes in adult offspring. The hippocampus shows a remarkable degree of structural plasticity, notably in response to stress and glucocorticoids. We hypothesized that PS would differentially affect hippocampal neurogenesis in rats selectively bred for genetic differences in anxiety-related behaviors and stress responsivity. Pregnant dams of high anxiety-related behavior (HAB) and low anxiety-related behavior (LAB) strains were stressed between days 5 and 20 of pregnancy. The survival of newly generated hippocampal cells was found to be significantly lower in 43-day-old HAB than in LAB male offspring of unstressed pregnancies. PS further reduced newly generated cell numbers only in HAB rats, and this was paralleled by a reduction in doublecortin-positive cell numbers, indicative of reduced neurogenesis. As maternal plasma corticosterone levels during PS were similar in both strains, we examined placental 11,-hydroxysteroid dehydrogenase type 2 (11,-HSD2), which catalyses rapid inactivation of maternal corticosterone to inert 11-dehydrocorticosterone and thus serves as a physiological ,barrier' to maternal glucocorticoids. PS significantly increased placental 11,-HSD2 activity in LAB, but not HAB, rats. We conclude that PS differentially affects the number of surviving newly generated cells and neurogenesis in HAB and LAB rats. The high sensitivity of hippocampal neurogenesis to PS in HAB rats is paralleled by a failure to increase placental 11,-HSD2 activity after stress rather than by different maternal corticosterone responses. Hence, stress-induced placental 11,-HSD2 expression may be critical in protecting the fetal brain from maternal stress-induced effects on adult neurogenesis. [source] Increased responsivity of glutamate release from the substantia nigra pars reticulata to striatal NMDA receptor blockade in a model of Parkinson's disease.EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 5 2000A dual probe microdialysis study in hemiparkinsonian rats Abstract Dual probe microdialysis was employed in freely moving 6-hydroxydopamine (6-OHDA) hemilesioned rats to investigate the effects of blockade of N-methyl-D-aspartate (NMDA) receptors in the dorsolateral striatum on glutamate (Glu) release from the ipsilateral substantia nigra pars reticulata (SNr). Perfusion for 60 min with the NMDA antagonist dizocilpine (0.1 and 1 ,m) in the dopamine (DA)-denervated striatum stimulated nigral Glu release (peak effect of 139 ± 7% and 138 ± 9%, respectively). The lower (0.01 ,m) and higher (10 ,m) concentrations were ineffective. In sham-operated rats, dizocilpine failed to affect nigral Glu release up to 1 ,m but induced a prolonged stimulation at 10 ,m (153 ± 9% at the end of perfusion). The present results show that DA-deficiency in the striatum of hemiparkinsonian rats is associated with increased responsivity of nigral Glu release to striatal NMDA receptor blockade. This suggests that changes of NMDA receptor mediated control of the striatofugal pathways occur during Parkinson's disease (PD). [source] The Cocoon of Power: Democratic Implications of Interinstitutional AgreementsEUROPEAN LAW JOURNAL, Issue 1 2007Sonja Puntscher Riekmann It starts from the premise that democratic rules as developed in the national context may be used as a yardstick for supranational governance as well. Thus, parliamentarisation of the Union is defined as an increase in democracy, although relating problems such as weak European party systems, low turnouts, and remoteness are not to be neglected. The article evaluates several case studies on IIAs in this vein and asks whether they strengthen the European Parliament or not, and why. It arrives at conclusions that allow for differentiation: empowerment of the European Parliament occurs in particular when authorisation to conclude an IIA stems from the Treaty or from the power that the European Parliament has in crucial fields such as the budget and is willing to use for this purpose. Success is, however, not guaranteed in every case, and is sometimes more symbolic than real. However, a democratic critique must also stress negative consequences of IIAs in terms of responsivity, accountability, and transparency. [source] Dopamine challenge tests as an indicator of psychological traitsHUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 2 2006P. Netter Abstract After discussing some introductory considerations about the value of challenge tests in general for discriminating personality dimensions which are considered extrapolations of psychopathological diseases, the present paper outlines the matter of responsivity to agonistic and antagonistic dopaminergic drugs or drugs of different mechanisms of action in the dopaminergic system, and elucidates that different hormones elicited by dopaminergic substances (prolactin, growth hormone) may indicate personality related differences in susceptibility of different brain areas. A further point was to demonstrate not only the well known relationship of dopaminergic hyperactivity with reward seeking and motivational factors associated with extraversion and novelty seeking, but also the relationship of dopaminergic hypofunction with the personality dimension of depression which had already been reported in studies on animals and psychiatric patients. A final point was to demonstrate that besides size of hormone responses additional parameters like time of response onset and initial prolactin increase can be used as biochemical indicators for identifying certain personality types, like highly depressive neurotic persons characterized by lower and later dopamine responses as compared to low depressives, and extraverted sensation-seeking types responding by an initial prolactin peak as opposed to low sensation seekers. Copyright © 2006 John Wiley & Sons, Ltd. [source] Plasma serotonin response to carbohydrate-rich food in chronic schizophrenic patients: clozapine versus classic antipsychotic agentsHUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 5 2001Yaffa Vered Abstract Researchers have reported a stimulatory effect of carbohydrate-rich intake on platelet-poor plasma (PPP) serotonin (5-HT) levels in healthy human subjects. Dietary manipulation may serve as a safer and less invasive means than pharmacologic challenge to provoke serotonergic responsivity in studies of schizophrenia. In the present study, we used the carbohydrate-rich meal test as an indicator of 5-HT activity in 12 patients with chronic schizophrenia maintained for at least 6 months on clozapine. PPP 5-HT levels were measured at baseline and at 1, 2 and 3,h after administration of the test. Findings were compared with those in schizophrenic patients treated with classic antipsychotic agents for the same duration. The maximal PPP 5-HT response was reached 120 min after meal administration in the clozapine-treated group and 60 min after in the classic antipsychotic-treated group (P<0.05 vs baseline for both). The 5-HT level (as percentage of baseline) at 60 min was significantly lower in the clozapine-treated group (P<0.02), as were individual PPP 5-HT peak values (P<0.05). The individual time to reach the peak response was similar in the two groups. Our results indicate that in patients with chronic schizophrenia 5-HT responsivity to the natural challenge of carbohydrate-rich meals is lower in those treated with clozapine than in those given classic antipsychotic agents. Values in both groups were lower than those in an appropriate historical comparative group of healthy subjects. We suggest that both clozapine and classic antipsychotic agents suppress serotonergic system sensitivity, but to a different degree. Copyright © 2001 John Wiley & Sons, Ltd. [source] The Perceptions of Infant Distress Signals Varying in Pitch by Cocaine-Using MothersINFANCY, Issue 1 2003Pamela Schuetze Perceptual responses to infant distress signals were studied in 16 cocaine-using and 15 comparison mothers. All mothers rated tape recordings of 48 replications of a newborn infant's hunger cry digitally altered to increase in fundamental frequency in 100-Hz increments. Cries were rated on 4 perceptual (arousing, aversive, urgent, and sick) and 6 caregiving rating scale items (clean, cuddle, feed, give pacifier, pick up, and wait and see) used in previous studies. Analyses of variance showed that, as cry pitch increased, cries were rated as more arousing, aversive, and urgent sounding. The highest pitched cries received the highest ratings for caregiving interventions. Main effects for cocaine use showed cocaine-using mothers (a) rated cries as less arousing, aversive, urgent, and sick; (b) indicated they were less likely to pick up or feed the infant; and (c) indicated they more likely to give the crying infant a pacifier or just "wait and see." A Group x Cry Pitch interaction effect showed that mothers in the cocaine group gave higher ratings to wait and see as the pitch of the cries increased, whereas mothers in the comparison group gave lower ratings to wait and see as the pitch of the cries increased. These ratings indicate that cocaine-using mothers found cries to be less perceptually salient and less likely to elicit nurturant caregiving responses. These results suggest that maternal cocaine use is associated with altered perceptions of infant distress signals that may provide the basis for differential social responsivity in the caregiving context. [source] Parenting of 7-month-old infants at familial risk for attention deficit/hyperactivity disorder,INFANT MENTAL HEALTH JOURNAL, Issue 2 2010Rivka Landau Patterns of interaction between parents and 7-month-old boys at familial risk for attention deficit/hyperactivity disorder (ADHD) and a comparison group were studied during a warm-up and two play episodes. The sample included 78 (47 at-risk, 31 comparison) mother,child and 45 (27 at-risk, 18 comparison) father,child dyads. A coding system developed by G. Kochanska (1997, 1998) was used. Infants in the risk group did not differ from the comparison group in the rate of emission of infant-related events. However, they received less adequate responsivity from both their fathers and their mothers to these events, and specifically to negative emotions or distress, than did the comparison group. Maternal psychopathology did not account for these findings. Mothers were more adequately responsive than were fathers, especially for physiological needs. The association between nonoptimal interaction in infancy and the development of ADHD is discussed. [source] Maternal depression and anxiety effects on the human fetus: Preliminary findings and clinical implications,INFANT MENTAL HEALTH JOURNAL, Issue 5 2008John N.I. Dieter Newborns of depressed and anxious mothers show biobehavioral abnormalities suggesting that maternal psychological distress has negative effects on the fetus. Two studies examined the fetuses of depressed and nondepressed mothers: (a) a cross-sectional investigation of fetal activity during the second and third trimesters and (b) an examination of behavioral and heart rate response to vibratory stimulation in late-gestation fetuses. Fetuses of depressed mothers were more active during the fifth, sixth, and seventh gestational months. Assessment of late-term fetuses consisted of a baseline, trials of vibratory stimulation directed towards measuring habituation, and a poststimulation period. During baseline, the fetuses of depressed mothers exhibited a lower heart rate. During stimulation trials, they showed less total movement and appeared to habituate more often. Approximately 35% of the variance in fetal behavior was accounted for by the mothers' depression and anxiety symptoms. Maternal depression may be linked to greater fetal activity during the second and third trimesters and decreased behavioral responsivity during late gestation. The response of late-term fetuses of depressed mothers to vibratory stimulation may reflect "receptor adaptation/effector fatigue" and not true habitation. Future studies should examine the value of clinical interventions provided to the pregnant mother. [source] Brain dopamine is associated with eating behaviors in humansINTERNATIONAL JOURNAL OF EATING DISORDERS, Issue 2 2003Nora D. Volkow Abstract Objective Eating behavior in humans is influenced by variables other than just hunger-satiety including cognitive restraint, emotional distress, and sensitivity to food stimuli. We investigate the role of dopamine (DA), a neurotransmitter involved with food motivation, in these variables. Methods We used the Dutch Eating Behavior Questionnaire (DEBQ) to measure Restraint, Emotionality, and Externality in 10 subjects. We correlated DEBQ scores with brain DA levels. Positron emission tomography and {11C}raclopride uptake were used to measure baseline D2 receptors (neutral stimulation) and to assess changes in extracellular DA to food stimulation (display of food). Results Restraint was correlated with DA changes with food stimulation (higher restraint, greater responsivity), emotionality was negatively correlated with baseline D2 receptors (higher emotionality, lower D2 receptors), whereas externality was not. These correlations were significant in the dorsal but not in the ventral striatum. Discussion These results provide evidence that DA in the dorsal striatum is involved with the restraint and emotionality components regulating eating behavior and that these two dimensions reflect different neurobiologic processes. © 2003 by Wiley Periodicals, Inc.Int J Eat Disord 33: 136,142, 2003. [source] How do implementation efforts relate to program adherence? examining the role of organizational, implementer, and program factorsJOURNAL OF COMMUNITY PSYCHOLOGY, Issue 6 2008Jacinda K. Dariotis Widespread replications of evidence-based prevention programs (EBPPs) prompt prevention scientists to examine program implementation adherence in real world settings. Based on Chen's model (1990), we identified five key factors of the implementation system and assessed which characteristics related to program adherence. The sample included 32 EBPPs and results indicate that target recipient responsivity, program material quality, implementer prioritization, community collaborative system support, and parental support significantly relate to program adherence. Several differences reached statistical significance, thereby highlighting the importance of these variables and the need for future studies with larger sample sizes to identify factors related to program adherence adequately. © 2008 Wiley Periodicals, Inc. [source] Particle surface temperature measurements with multicolor band pyrometryAICHE JOURNAL, Issue 1 2009Hong Lu Abstract A noncontact, color-band pyrometer, based on widely available, inexpensive digital imaging devices, such as commercial color cameras, and capable of pixel-by-pixel resolution of particle-surface temperature and emissivity is demonstrated and described. This diagnostic instrument is ideally suited to many combustion environments. The devices used in this method include color charge-coupled device (CCD), or complementary metal oxide semiconductor (CMOS) digital camera, or any other color-rendering camera. The color camera provides spectrally resolved light intensity data of the image, most commonly for three color bands (Red, Green, and Blue,), but in some cases for four or more bands or for a different set of colors. The CCD or CMOS sensor-mask combination has a specific spectral response curve for each of these color bands that spans the visible and often near infrared spectral range. A theory is developed, based on radiative heat transfer and camera responsivity that allows quantitative surface temperature distribution calculation, based on a photograph of an object in emitted light. Particle surface temperature calculation is corrected by heat transfer analysis with reflection between the particle and reactor wall for particles located in furnace environments, but such corrections lead to useful results only when the particle temperature is near or below the wall temperatures. Wood particle-surface temperatures were measured with this color-band pyrometry during pyrolysis and combustion processes, which agree well with thermocouple measured data. Particle-surface temperature data simultaneously measured from three orthogonal directions were also mapped onto the surface of a computer generated 3-D (three-dimensional) particle model. © 2008 American Institute of Chemical Engineers AIChE J, 2009 [source] Examining the Intersection of Sex and Stress in Modelling Neuropsychiatric DisordersJOURNAL OF NEUROENDOCRINOLOGY, Issue 4 2009N. Goel Sex-biased neuropsychiatric disorders, including major depressive disorder and schizophrenia, are the major cause of disability in the developed world. Elevated stress sensitivity has been proposed as a key underlying factor in disease onset. Sex differences in stress sensitivity are associated with corticotrophin-releasing factor (CRF) and serotonin neurotransmission, which are important central regulators of mood and coping responses. To elucidate the underlying neurobiology of stress-related disease predisposition, it is critical to develop appropriate animal models of stress pathway dysregulation. Furthermore, the inclusion of sex difference comparisons in stress responsive behaviours, physiology and central stress pathway maturation in these models is essential. Recent studies by our laboratory and others have begun to investigate the intersection of stress and sex where the development of mouse models of stress pathway dysregulation via prenatal stress experience or early-life manipulations has provided insight into points of developmental vulnerability. In addition, examination of the maturation of these pathways, including the functional importance of the organisational and activational effects of gonadal hormones on stress responsivity, is essential for determination of when sex differences in stress sensitivity may begin. In such studies, we have detected distinct sex differences in stress coping strategies where activational effects of testosterone produced females that displayed male-like strategies in tests of passive coping, but were similar to females in tests of active coping. In a second model of elevated stress sensitivity, male mice experiencing prenatal stress early in gestation showed feminised physiological and behavioural stress responses, and were highly sensitive to a low dose of selective serotonin reuptake inhibitors. Analyses of expression and epigenetic patterns revealed changes in CRF and glucocorticoid receptor genes in these mice. Mechanistically, stress early in pregnancy produced a significant sex-dependent effect on placental gene expression that was supportive of altered foetal transport of key growth factors and nutrients. These mouse models examining alterations and hormonal effects on development of stress pathways provide necessary insight into how specific stress responses can be reprogrammed early in development resulting in sex differences in stress sensitivity and neuropsychiatric disease vulnerability. [source] Changes in Expression of the Genes for the Leptin Receptor and the Growth Hormone-Releasing Peptide/Ghrelin Receptor in the Hypothalamic Arcuate Nucleus with Long-Term Manipulation of Adiposity by Dietary MeansJOURNAL OF NEUROENDOCRINOLOGY, Issue 6 2005Y. Kurose Abstract Changes in leptin and ghrelin levels occur with alterations in adiposity, but signalling may be affected by levels of the relevant receptors. We measured expression of the leptin receptor (Ob-Rb) and the ghrelin/growth hormone releasing peptide receptor (GHS-R) in the arcuate nucleus of sheep held at either high or low levels of adiposity. Plasma growth hormone (GH) levels were lower in Fat animals and higher in Lean animals. Plasma insulin and leptin levels were higher in Fat animals and lower in Lean animals. Frozen hypothalamic sections of arcuate nucleus were extracted and mRNA levels measured for mRNA for Ob-Rb and GHS-R. Gene expression for both Ob-Rb and GHS-R was higher in Lean animals than in Fat animals, with no difference in expression between Fat and Normal animals. A second group of animals (n = 4 per group) was used for double-labelling immunohistochemistry to determine whether the increase in Ob-Rb gene expression was translated into Ob-Rb protein and to ascertain whether this effect is localised to the cells of the arcuate nucleus that produce either neuropeptide Y (NPY) and/or pro-opiomelanocortin-derived peptides. Lean animals displayed a 255% increase in immunoreactive NPY cells (P < 0.005), a 167% increase in cells with Ob-Rb (P < 0.037) protein and a 344% increase in cells that were staining for both NPY and Ob-Rb (P < 0.02). There was no difference between the Normal and Lean animals in the number of cells that were detected with an adrenocorticotrophic hormone (ACTH) antibody or the number of ACTH-immunoreactive cells that also stained for Ob-Rb. Finally, we measured plasma ghrelin levels in Normal, Fat and Lean ewes (n = 4/group); levels were higher (P < 0.05) in Fat animals than in Lean animals. We conclude that lowering body weight leads to increased expression of Ob-Rb, ghrelin/GHS-R expression and proportion of NPY cells that express Ob-Rb in the arcuate nucleus. This may be an adaptive mechanism to increase responsivity to both leptin and ghrelin. [source] Prenatal Alcohol Exposure and Chronic Mild Stress Differentially Alter Depressive- and Anxiety-Like Behaviors in Male and Female OffspringALCOHOLISM, Issue 4 2010Kim G. C. Hellemans Background:, Fetal Alcohol Spectrum Disorder (FASD) is associated with numerous neurobehavioral alterations, as well as disabilities in a number of domains, including a high incidence of depression and anxiety disorders. Prenatal alcohol exposure (PAE) also alters hypothalamic-pituitary-adrenal (HPA) function, resulting in increased responsiveness to stressors and HPA dysregulation in adulthood. Interestingly, data suggest that pre-existing HPA abnormalities may be a major contributory factor to some forms of depression, particularly when an individual is exposed to stressors later in life. We tested the hypothesis that exposure to stressors in adulthood may unmask an increased vulnerability to depressive- and anxiety-like behaviors in PAE animals. Methods:, Male and female offspring from prenatal alcohol (PAE), pair-fed (PF), and ad libitum-fed control (C) treatment groups were tested in adulthood. Animals were exposed to 10 consecutive days of chronic mild stress (CMS), and assessed in a battery of well-validated tasks sensitive to differences in depressive- and/or anxiety-like behaviors. Results:, We report here that the combination of PAE and CMS in adulthood increases depressive- and anxiety-like behaviors in a sexually dimorphic manner. PAE males showed impaired hedonic responsivity (sucrose contrast test), locomotor hyperactivity (open field), and alterations in affiliative and nonaffiliative social behaviors (social interaction test) compared to control males. By contrast, PAE and, to a lesser extent, PF, females showed greater levels of "behavioral despair" in the forced swim test, and PAE females showed altered behavior in the final 5 minutes of the social interaction test compared to control females. Conclusions:, These data support the possibility that stress may be a mediating or contributing factor in the psychopathologies reported in FASD populations. [source] Alcoholism and Dampened Temporal Limbic Activation to Emotional FacesALCOHOLISM, Issue 11 2009Ksenija Marinkovic Background:, Excessive chronic drinking is accompanied by a broad spectrum of emotional changes ranging from apathy and emotional flatness to deficits in comprehending emotional information, but their neural bases are poorly understood. Methods:, Emotional abnormalities associated with alcoholism were examined with functional magnetic resonance imaging in abstinent long-term alcoholic men in comparison to healthy demographically matched controls. Participants were presented with emotionally valenced words and photographs of faces during deep (semantic) and shallow (perceptual) encoding tasks followed by recognition. Results:, Overall, faces evoked stronger activation than words, with the expected material-specific laterality (left hemisphere for words, and right for faces) and depth of processing effects. However, whereas control participants showed stronger activation in the amygdala and hippocampus when viewing faces with emotional (relative to neutral) expressions, the alcoholics responded in an undifferentiated manner to all facial expressions. In the alcoholic participants, amygdala activity was inversely correlated with an increase in lateral prefrontal activity as a function of their behavioral deficits. Prefrontal modulation of emotional function as a compensation for the blunted amygdala activity during a socially relevant face appraisal task is in agreement with a distributed network engagement during emotional face processing. Conclusions:, Deficient activation of amygdala and hippocampus may underlie impaired processing of emotional faces associated with long-term alcoholism and may be a part of the wide array of behavioral problems including disinhibition, concurring with previously documented interpersonal difficulties in this population. Furthermore, the results suggest that alcoholics may rely on prefrontal rather than temporal limbic areas in order to compensate for reduced limbic responsivity and to maintain behavioral adequacy when faced with emotionally or socially challenging situations. [source] Electrical Response to Organic Vapor of Conductive Composites from Amorphous Polymer/Carbon Black Prepared by Polymerization FillingMACROMOLECULAR MATERIALS & ENGINEERING, Issue 2 2003Jun Rong Li Abstract In recent years, conductive polymer composites have found applications as gas sensors because of their sudden change in electric resistance of several orders of magnitude when the materials are exposed to certain solvent vapors. However, the composites having this function reported so far are mostly based on crystalline polymeric matrices, which factually sets a limit to materials selection. The present work prepares polystyrene/carbon black composites through polymerization filling and proves that the amorphous polymer composites can also serve as gas sensing materials. The composites' percolation threshold is much lower than that of the composites produced by dispersive mixing. In addition, high responsivity to some organic vapors coupled with sufficient reproducibility is acquired. The experimental data show that molecular weight and molecular weight distribution of the matrix polymer and conducting filler content exert great influence on the electrical response behavior of the composites. As a result, composites performance can be purposely tailored accordingly. Compared with the approaches of melt-blending and solution-blending, the current technique is characterized by many advantages, such as simplicity, low cost, and easy to be controlled. Effect of different organic solvent vapors on the electric resistance of PS/CB composites (CB content,=,10.35 vol.-%). [source] The electroolfactogram: A review of its history and usesMICROSCOPY RESEARCH AND TECHNIQUE, Issue 3 2002John W. Scott Abstract The electroolfactogram (EOG) is a negative electrical potential recorded at the surface of the olfactory epithelium of vertebrates. It represents primarily, if not exclusively, the summated generator potential in the olfactory receptor neurons (ORNs). While a number of studies suggest that secretory or inhibitory events may also contribute to the EOG, these are not well established. This review outlines (1) the cellular and physiological nature of the EOG response; (2) methodological considerations regarding odor selection and delivery, surgical preparation, response descriptions, and analysis; and (3) application of the EOG in human, fish, and insect olfaction and pheromonal responsivity. A number of technical issues associated with EOG recording are also discussed. Microsc. Res. Tech. 58:152,160, 2002. © 2002 Wiley-Liss, Inc. [source] Characterization of uni-traveling carrier photodiodes for high-linearity and high-SNR applicationsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 4 2010Andreas O. J. Wiberg Abstract A typical uni-traveling carrier photodiode (UTC-PD) and a commercial PIN-PD are compared in the context of the analog performance at 10 GHz in a realistic noise environment. The behavior of the carrier-to-noise ratio (CNR), the linearity, represented by the third-order output intercept point (OIP3), and the spurious free dynamic range are studied as a function of photocurrent. We have found that the increment of the CNR is only minor because of excess noise of the amplifier, as an optical amplifier is used to reach high optical power. However, the OIP3 of the UTC-PD is substantially higher and increases with photocurrent, in contrast to the PIN-PD. Thus, even though the responsivity is lower, it is beneficial to use a UTC-PD to have superior dynamic range. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:984,987, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25055 [source] Photodynamic Actinometry Using Microspheres: Concept, Development and Responsivity ,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2004Stuart K. Bisland ABSTRACT Photodynamic therapy (PDT) relies on three main ingredients, oxygen, light and photoactivating compounds, although the PDT response is definitively contingent on the site and level of reactive oxygen species (ROS) generation. This study describes the development of a novel, fluorescent-based actinometer microsphere system as a means of discerning spatially resolved dosimetry of total fluence and ROS production. Providing a high resolution, localized, in situ measurement of fluence and ROS generation is critical for developing in vivo PDT protocols. Alginate-poly- l -lysine-alginate microspheres were produced using ionotropic gelation of sodium alginate droplets, ranging from 80 to 200 ,m in diameter, incorporating two dyes, ADS680WS (ADS) and Rhodophyta-phycoerythrin (RPE), attached to the spheres' inside and outside layers, respectively. To test the responsivity and dynamic range of RPE for ROS detection, the production of ROS was initiated either chemically using increasing concentrations of potassium perchromate or photochemically using aluminum tetrasulphonated phthalocyanine. The generation of singlet oxygen was confirmed by phosphorescence at 1270 nm. The resulting photodegradation and decrease in fluorescence of RPE was found to correlate with increased perchromate or PDT treatment fluence, respectively. This effect was independent of pH (6.5,8) and could be inhibited using sodium azide. RPE was not susceptible to photobleaching with light alone (670 nm; 150 Jcm,2). ADS, which absorbs light between 600 and 750 nm, showed a direct correlation between radiant exposure (670 nm; 0,100 Jcm,2) and diminished fluorescence. Photobleaching was independent of irradiance (10,40 mW cm,2). We propose that actinometer microspheres may provide a means for obtaining high spatial resolution information regarding delivered PDT dose within model systems during investigational PDT development and dosimetric information for clinical extracorporeal PDT as in the case of ex vivo bone marrow purging. [source] PIN diamond detector development for LYRA, the solar VUV radiometer on board PROBA IIPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 11 2004A. BenMoussa Abstract LYRA (the LYman-alpha RAdiometer onboard PROBA-2) will use diamond detectors for the first time in space solar physics. A set of measurement campaigns was designed to obtain the EUV-to-VIS characterization of the diamond detectors and knowledge of their modes of operation. The outputs of this campaign provide the reference data needed for the optimization of the detectors, and for the LYRA channels definition. The measurements of responsivity in EUV and VUV spectral ranges have been carried out by the Physkalisch-Technische Bundesanstalt (PTB) in Germany at the electron storage ring BESSY II. The detectors spectral responsivity measurements R(,) was done for the following wavelength ranges: 40 to 80 nm, 80 to 120 nm and 120 to 240 nm. The longer wavelength range from 210 nm to 827 nm was measured with the monochromatic light by using a Xe-lamp at IMO-IMOMEC. The diodes exhibit high photoresponse in the deep UV region and over five orders of magnitude in discrimination between deep UV (200 nm) and visible light (550 nm). (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] High performance Schottky UV detectors (265,100 nm) using n-Al0.5Ga0.5N on AlN epitaxial layerPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2003H. Miyake Abstract A high responsivity spectrum in the near ultraviolet (UV) and the vacuum UV (VUV) region was realized using Schottky UV detectors consisting of Al0.5Ga0.5N on an AlN epitaxial layer. The cut-off wavelength of AlGaN UV detectors was 4.7 eV (265 nm), a value that corresponds to the band gap of Al0.5Ga0.5N. The contrast of responsivity between the near UV and the visible was about 104. The GaN Schottky detector hads a high responsivity region in the near-UV from 3.4 to 5.0 eV (250,360 nm), whereas the AlGaN UV detector had a high responsivity in the UV,VUV region from 4.7 to 12.4 eV (100,265 nm). From these results, the fabricated AlGaN-based UV photodetectors can likely be used in detectors for the UV,VUV region. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||||||||||||||||||||