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Arc
Kinds of Arc Terms modified by Arc Selected AbstractsPhysiological functions of glucose-inhibited neuronesACTA PHYSIOLOGICA, Issue 1 2009D. Burdakov Abstract Glucose-inhibited neurones are an integral part of neurocircuits regulating cognitive arousal, body weight and vital adaptive behaviours. Their firing is directly suppressed by extracellular glucose through poorly understood signalling cascades culminating in opening of post-synaptic K+ or possibly Cl, channels. In mammalian brains, two groups of glucose-inhibited neurones are best understood at present: neurones of the hypothalamic arcuate nucleus (ARC) that express peptide transmitters NPY and agouti-related peptide (AgRP) and neurones of the lateral hypothalamus (LH) that express peptide transmitters orexins/hypocretins. The activity of ARC NPY/AgRP neurones promotes food intake and suppresses energy expenditure, and their destruction causes a severe reduction in food intake and body weight. The physiological actions of ARC NPY/AgRP cells are mediated by projections to numerous hypothalamic areas, as well as extrahypothalamic sites such as the thalamus and ventral tegmental area. Orexin/hypocretin neurones of the LH are critical for normal wakefulness, energy expenditure and reward-seeking, and their destruction causes narcolepsy. Orexin actions are mediated by highly widespread central projections to virtually all brain areas except the cerebellum, including monosynaptic innervation of the cerebral cortex and autonomic pre-ganglionic neurones. There, orexins act on two specific G-protein-coupled receptors generally linked to neuronal excitation. In addition to sensing physiological changes in sugar levels, the firing of both NPY/AgRP and orexin neurones is inhibited by the ,satiety' hormone leptin and stimulated by the ,hunger' hormone ghrelin. Glucose-inhibited neurones are thus well placed to coordinate diverse brain states and behaviours based on energy levels. [source] Inheritance of resistance against biotype 2 of the Asian rice gall midge, Orseolia oryzaeENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 1 2000J. Pani Abstract The inheritance of resistance in the rice cultivars Phalguna, ARC5984, ARC 5158, Veluthacheera, and T1477 to the Asian rice gall midge biotype 2 was studied under both natural and artificial infestation conditions against the susceptible cultivars Jaya and IR20. A single recessive gene in Veluthacheera and two recessive complementary genes in T1477 control resistance. Phalguna and ARC5984 possess a single dominant gene while ARC5158 has a single dominant and a single recessive gene for resistance. Allelism studies showed that genes for resistance in Veluthacheera and T1477 are allelic but non-allelic to the resistance genes in Phalguna and ARC5984, which are allelic to each other. Genes for resistance in ARC5158 are allelic to resistance genes of the other four donors. There was no cytoplasmic inhibition of resistance by the susceptible parents. [source] In vitro study of mean loads and modes of failure of all-ceramic crowns cemented with light-cured or dual-cured luting cement, after 1 and 30 d of storageEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 1 2008Melissa-L. This study compared the mean loads and modes of failure of teeth restored with all-ceramic crowns (ACCs) cemented with dual-cured (RelyX ARC; 3M ESPE) or light-cured (RelyX Veneer; 3M ESPE) luting cements. Clinically, there are advantages of light-cured cements over the recommended dual-cured cements, namely increased working time, improved handling, colour stability, and a homogenous mix. Forty, sound, extracted, human, premolar teeth underwent a standardized preparation for ACCs. IPS Empress (Ivoclar-Vivadent) crowns of standard dimensions were fabricated and 20 were cemented with each cement. The crowns were stored for 1 or 30 d in water and subjected to a compressive load to failure at 0.017 mm s,1. There were no significant differences in loads at failure, between each cement group, at each storage period, and there were no significant differences in loads at failure, for each cement, at 1 and 30 d of storage. There were also no significant differences in modes of failure between each cement group. Before recommending light-cured cement as an alternative to dual-cured cement for the cementation of all-ceramic crowns, further research is required to establish the depth of ceramic at which light-cured lutes fail to polymerize completely. [source] Adaptive robust control of nonlinear systems with dynamic uncertaintiesINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 4 2009Xiangbin Liu Abstract In this paper, the discontinuous projection-based adaptive robust control (ARC) approach is extended to a class of nonlinear systems subjected to parametric uncertainties as well as all three types of nonlinear uncertainties,uncertainties could be state-dependent, time-dependent, and/or dynamic. Departing from the existing robust adaptive control approach, the proposed approach differentiates between dynamic uncertainties with and without known structural information. Specifically, adaptive robust observers are constructed to eliminate the effect of dynamic uncertainties with known structural information for an improved steady-state output tracking performance,asymptotic output tracking is achieved when the system is subjected to parametric uncertainties and dynamic uncertainties with known structural information only. In addition, dynamic normalization signals are introduced to construct ARC laws to deal with other uncertainties including dynamic uncertainties without known structural information not only for global stability but also for a guaranteed robust performance in general. Copyright © 2008 John Wiley & Sons, Ltd. [source] Observer-based adaptive robust control of a class of nonlinear systems with dynamic uncertainties,INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 4 2001Bin Yao Abstract In this paper, a discontinuous projection-based adaptive robust control (ARC) scheme is constructed for a class of nonlinear systems in an extended semi-strict feedback form by incorporating a nonlinear observer and a dynamic normalization signal. The form allows for parametric uncertainties, uncertain nonlinearities, and dynamic uncertainties. The unmeasured states associated with the dynamic uncertainties are assumed to enter the system equations in an affine fashion. A novel nonlinear observer is first constructed to estimate the unmeasured states for a less conservative design. Estimation errors of dynamic uncertainties, as well as other model uncertainties, are dealt with effectively via certain robust feedback control terms for a guaranteed robust performance. In contrast with existing conservative robust adaptive control schemes, the proposed ARC method makes full use of the available structural information on the unmeasured state dynamics and the prior knowledge on the bounds of parameter variations for high performance. The resulting ARC controller achieves a prescribed output tracking transient performance and final tracking accuracy in the sense that the upper bound on the absolute value of the output tracking error over entire time-history is given and related to certain controller design parameters in a known form. Furthermore, in the absence of uncertain nonlinearities, asymptotic output tracking is also achieved. Copyright © 2001 John Wiley & Sons, Ltd. [source] Effect of water storage time and composite cement thickness on fatigue of a glass-ceramic trilayer systemJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2008Nelson R. F. A. Silva Abstract Aim. Static Hertzian contact tests of monolayer glass-ceramics in trilayer configurations (glass-ceramic/cement/composite) have shown that thick cement layers lower strength. This study sought to test the hypothesis that thick resin cement layers lower mouth motion fatigue reliability for flat glass-ceramic/cement/composite trilayer systems and that aging in water reduces reliability. Methods. Dicor plates (n , 12 per group) (10 × 10 × 0.8 mm3) were aluminum-oxide abraded (50 ,m), etched (60 s), silanized, and bonded (Rely X ARC) to water aged (30 days) Z100 resin blocks (10 × 10 × 4 mm3). Four groups were prepared: (1) thick cement layer (>100 ,m) stored in water for 24,48 h, (2) thick cement layer stored for 60 days, (3) thin cement layer (,100 ,m) stored for 24,48 h, and (4) thin cement layer stored for 60 days. The layered structures were fatigued (2 Hz) utilizing mouth motion loading with a step-stress acceleration method. A master Weibull distribution was calculated and reliability determined (with 90% confidence intervals) at a given number of cycles and load. Results. The aged group (60 d) with thick cement layer had statistically lower reliability for 20,000 cycles at 150 N peak load (0.11) compared with both nonaged groups (24,48 h) (thin layer = 0.90 and thick layer = 0.82) and aged group with thin cement layer (0.89). Conclusion. Trilayer specimens with thick cement layers exhibited significantly lower reliability under fatigue testing only when stored for 60 days in water. The hypothesis was accepted. These results suggest that diffusion of water into the resin cement and also to the glass-ceramic interface is delayed in the thick cement specimens at 24,48 h. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008 [source] ARC protects rat cardiomyocytes against oxidative stress through inhibition of caspase-2 mediated mitochondrial pathwayJOURNAL OF CELLULAR BIOCHEMISTRY, Issue 2 2006Yi-Qiang Zhang Abstract Apoptosis repressor with a CARD domain (ARC) has been demonstrated to protect heart cells against ischemia/reperfusion (I/R) injury. In this study, we investigated the mechanism by which ARC protects heart cells against oxidative stress. We monitored the extent of apoptosis and activity of multiple components of the intrinsic apoptotic pathway in rat cardiac myoblast cell line H9c2 with either reduced or increased expression of ARC during oxidative stress. Overexpression of ARC-inhibited oxidative stress-induced caspase-2/3 activation, cytochrome c release, and translocation of Bax to mitochondria. Furthermore, phosphorylation of ARC at threonine 149 was found to be critical to its function. ARC containing a T149A mutation failed to translocate to mitochondria, did not inhibit caspase-2 activation, and had a dominant negative effect against the protective effect of endogenous ARC during oxidative stress. In addition, wild-type ARC but not the T149A mutant inhibited cell death induced by overexpression of caspase-2. Using a yeast two-hybrid (YTH) screening approach and co-immunoprecipitation (Co-IP), we found that protein phosphatase 2C (PP2C) interacted with ARC and that PP2C mediated-dephosphorylation of ARC inhibited its anti-apoptotic activity. Eliminating either the N-terminal CARD domain or the C-terminal P/E domain also abolished the anti-apoptotic function of ARC, suggesting that full-length ARC is required for its apoptotic inhibition. These results indicate that ARC plays an important role in protection of H9c2 cells against oxidative stress-induced apoptosis by phosphorylation-dependent suppression of the mitochondria-mediated intrinsic pathway, partially initiated through the activation of caspase-2. J. Cell. Biochem. 99: 575,588, 2006. © 2006 Wiley-Liss, Inc. [source] Influence of cardiac-specific overexpression of insulin-like growth factor 1 on lifespan and aging-associated changes in cardiac intracellular Ca2+ homeostasis, protein damage and apoptotic protein expressionAGING CELL, Issue 6 2007Qun Li Summary A fall in circulating levels of cardiac survival factor insulin-like growth factor 1 (IGF-1) contributes to cardiac aging. To better understand the role of IGF-1 in cardiac aging, we examined the influence of cardiac IGF-1 overexpression on lifespan, cardiomyocyte intracellular Ca2+ homeostasis, protein damage, apoptosis and expression of pro- and anti-apoptotic proteins in young and old mice. Mouse survival rate was constructed by the Kaplan,Meier curve. Intracellular Ca2+ was evaluated by fura-2 fluorescence. Protein damage was determined by protein carbonyl formation. Apoptosis was assessed by caspase-8 expression, caspase-3 and TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling) assay. Pro- and anti-apoptotic proteins including Bax, p53, pp53, Bcl2, Omi/HtrA2, apoptosis repressor with caspase recruitment domain (ARC) and X-linked inhibitor of apoptosis protein (XIAP) were assessed by Western blot. Aging decreased plasma in IGF-1 levels, elevated myocyte resting intracellular Ca2+ levels, reduced electrically stimulated rise in intracellular Ca2+ and delayed intracellular Ca2+ decay associated with enhanced protein carbonyl formation, caspase-8 expression and caspase-3 activity in FVB mice, all of which with the exception of elevated resting intracellular Ca2+ were attenuated by IGF-1. Aging up-regulated expression of Bax, Bcl2 and ARC, down-regulated XIAP expression and did not affect p53, pp53 and Omi/HtrA2. The IGF-1 transgene attenuated or nullified aging-induced changes in Bax, Bcl2 and XIAP. Our data suggest a beneficial role for IGF-1 in aging-induced survival, cardiac intracellular Ca2+ homeostasis, protein damage and apoptosis possibly related to pro- and anti-apoptotic proteins. [source] Increased volume of coverage for abdominal contrast-enhanced MR angiography with two-dimensional autocalibrating parallel imaging: Initial experience at 3.0 TeslaJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 5 2009Darren P. Lum MD Abstract Purpose: To assess the feasibility and the quality of abdominal three-dimensional (3D) contrast enhanced MR angiograms acquired at 3.0 Tesla (T) using a new 2D-accelerated autocalibrating parallel reconstruction method for Cartesian sampling (2D-ARC). Materials and Methods: With institutional review board approval and written informed consent, a prospective trial in 6 normal healthy volunteers and 23 patients referred for evaluation of suspected renovascular disease was performed. The volunteers underwent abdominal MRA with and without 2D-ARC acceleration. Images were evaluated independently by two blinded vascular radiologists in randomized order. Vessel conspicuity was rated on a five-point scale. Evaluation for significant differences between the scores for each technique was performed using a Wilcoxon signed-rank test. Results: In the series of six volunteers, no statistical significance was found between the image quality scores for 2D-ARC accelerated and nonaccelerated exams. A high proportion of the 23 clinical 2D-ARC exams were graded as diagnostic (vessel conspicuity score ,2; Reader 1, 96%; Reader 2, 100%) for overall image quality. Conclusion: Subjective image quality of 2D-ARC accelerated MRA was equivalent to the conventional MRA method. However, the 2D-ARC accelerated sequence provided a 3.5-fold increase in imaging volume, complete abdominal coverage, and a 30% reduction in voxel volume, all within the same acquisition time. J. Magn. Reson. Imaging 2009;30:1093,1100. © 2009 Wiley-Liss, Inc. [source] Cretaceous high- P granulites at Milford Sound, New Zealand: metamorphic history and emplacement in a convergent margin settingJOURNAL OF METAMORPHIC GEOLOGY, Issue 4 2000G. L. Clarke Granulite facies orthogneiss of the Arthur River Complex (ARC) at Milford Sound, western Fiordland records a complex Early Cretaceous magmatic and orogenic history for the Pacific Gondwana margin that culminated in the emplacement and burial of a dioritic batholith, the Western Fiordland Orthogneiss (WFO). Enstatite-bearing mafic to intermediate protoliths of the ARC and WFO intruded the middle to upper crust. The early deformation history of the ARC is preserved in the Pembroke Granulite, where two-pyroxene S1 assemblages that reflect P<8 kbar and T >750 °C were only patchily recrystallized during later deformation. S1 is cut by garnet-bearing, leucogabbroic to dioritic veins, which are cut by distinctive D2 fractures involving anorthositic veins and garnet,diopside,plagioclase-bearing reaction zones. These zones are widespread in the ARC and WFO and record conditions of P,14 kbar and T >750 °C. Garnet,clinopyroxene-bearing corona reaction textures that mantle enstatite in both the ARC and WFO reflect Early Cretaceous burial by approximately 25 km of continental crust. Most of the ARC is formed from the Milford and Harrison Gneisses, which contain steeply dipping S4 assemblages that envelop the Pembroke Granulite and involve garnet, hornblende, diopside, clinozoisite, rutile and plagioclase, with or without kyanite. The P,T history of rocks in western Fiordland reflects pronounced Early Cretaceous convergence-related tectonism and burial, possibly related to the collision and accretion of island arc material onto the Pacific Gondwana margin. [source] Activity of Hypothalamic Dopaminergic Neurones During the Day of Oestrus: Involvement in Prolactin SecretionJOURNAL OF NEUROENDOCRINOLOGY, Issue 10 2010C. M. Leite A secretory surge of prolactin occurs on the afternoon of oestrus in cycling rats. Pituitary prolactin is inhibited by dopamine. We evaluated the activity of the neuroendocrine dopaminergic neurones during oestrus and dioestrus, as determined by dopaminergic activity in the median eminence and neurointermediate lobe of the pituitary, as well as Fos-related antigen expression in tyrosine hydroxylase (TH)-immunoreactive (ir) neurones of the arcuate nucleus (ARC) and periventricular nucleus (Pe). During oestrus, the 4-dihydroxyphenylacetic acid/dopamine ratio in the median eminence decreased at 16.00 h, coinciding with the increase in plasma prolactin levels. Similarly, the expression of Fos-related antigen in TH-ir neurones of Pe and rostral-, dorsomedial- and caudal-ARC also decreased at 16.00 h. On dioestrus, 4-dihydroxyphenylacetic acid/dopamine ratio in the median eminence and Fos-related antigen expression in TH-ir neurones of Pe and rostral-ARC decreased at 18.00 h, whereas prolactin levels were unaltered. No variation in dopaminergic activity was found in the neurointermediate lobe of the pituitary on either oestrus or dioestrus. The number of TH-ir neurones in the ARC and parameters of dopaminergic activity were found to be generally lower on oestrus compared to dioestrus. The transitory decrease in the activity of neuroendocrine dopaminergic neurones temporally associated with the prolactin surge on the afternoon of oestrus suggests a role for dopamine in the generation of the oestrous prolactin surge. [source] Neurokinin 3 Receptor Immunoreactivity in the Septal Region, Preoptic Area and Hypothalamus of the Female Sheep: Colocalisation in Neurokinin B Cells of the Arcuate Nucleus but not in Gonadotrophin-Releasing Hormone NeuronesJOURNAL OF NEUROENDOCRINOLOGY, Issue 1 2010M. Amstalden Recent evidence has implicated neurokinin B (NKB) in the complex neuronal network mediating the effects of gonadal steroids on the regulation of gonadotrophin-releasing hormone (GnRH) secretion. Because the neurokinin 3 receptor (NK3R) is considered to mediate the effects of NKB at the cellular level, we determined the distribution of immunoreactive NK3R in the septal region, preoptic area (POA) and hypothalamus of the ewe. NK3R cells and/or fibres were found in areas including the bed nucleus of the stria terminalis, POA, anterior hypothalamic and perifornical areas, dopaminergic A15 region, dorsomedial and lateral hypothalamus, arcuate nucleus (ARC) and the ventral premammillary nucleus. We also used dual-label immunocytochemistry to determine whether a neuroanatomical basis for direct modulation of GnRH neurones by NKB was evident. No GnRH neurones at any rostral-caudal level were observed to contain NK3R immunoreactivity, although GnRH neurones and fibres were in proximity to NK3R-containing fibres. Because NKB fibres formed close contacts with NKB neurones in the ARC, we determined whether these NKB neurones also contained immunoreactive NK3R. In luteal-phase ewes, 64% ± 11 of NKB neurones colocalised NK3R. In summary, NK3R is distributed in areas of the sheep POA and hypothalamus known to be involved in the control of reproductive neuroendocrine function. Colocalisation of NK3R in NKB neurones of the ARC suggests a potential mechanism for the autoregulation of this subpopulation; however, the lack of NK3R in GnRH neurones suggests that the actions of NKB on GnRH neurosecretory activity in the ewe are mediated indirectly via other neurones and/or neuropeptides. [source] Gonadotrophin-Releasing Hormone Pulse Generator Activity in the Hypothalamus of the GoatJOURNAL OF NEUROENDOCRINOLOGY, Issue 10 2009S. Ohkura Pulsatile release of gonadotrophin-releasing hormone (GnRH) is indispensable to maintain normal gonadotrophin secretion. The pulsatile secretion of GnRH is associated with synchronised electrical activity in the mediobasal hypothalamus (i.e. multiple unit activity; MUA), which is considered to reflect the rhythmic oscillations in the activity of the neuronal network that drives pulsatile GnRH secretion. However, the cellular source of this ultradian rhythm in GnRH activity is unknown. Direct input from kisspeptin neurones in the arcuate nucleus (ARC) to GnRH cell bodies in the medial preoptic area or their terminals in the median eminence could be the intrinsic source for driving the GnRH pulse generator. To determine whether kisspeptin signalling could be responsible for producing pulsatile GnRH secretion, we studied goats, measured plasma levels of luteinising hormone (LH) and recorded MUA in the posterior ARC, where the majority of kisspeptin neuronal cell bodies are located. Rhythmic volleys of MUA were found to be accompanied by LH pulses with regular intervals in the ARC, where kisspeptin neuronal cell bodies were found. Exogenous administration of kisspeptin stimulated a sustained increase in LH secretion, without influencing MUA, suggesting that the GnRH pulse generator, as reflected by MUA, originated from outside of the network of GnRH neurones, and could plausibly reflect the pacemaker activity of kisspeptin neurones, whose projections reach the median eminence where GnRH fibres project. These observations suggest that the kisspeptin neurones in the ARC may be the intrinsic source of the GnRH pulse generator. [source] Possible Role of Oestrogen in Pubertal Increase of Kiss1/Kisspeptin Expression in Discrete Hypothalamic Areas of Female RatsJOURNAL OF NEUROENDOCRINOLOGY, Issue 6 2009K. Takase Kisspeptin, a peptide encoded by the Kiss1 gene, has been considered as a potential candidate for a factor triggering the onset of puberty, and its expression in the hypothalamus was found to increase during peripubertal period in rodent models. The present study aimed to clarify the oestrogenic regulation of peripubertal changes in Kiss1 mRNA expression in the anteroventral periventricular nucleus (AVPV) and hypothalamic arcuate nucleus (ARC), and to determine which population of kisspeptin neurones shows a change in kisspeptin expression parallel to that in luteinising hormone (LH) pulses at the peripubertal period. Quantitative reverse transcriptase-polymerase chain reaction and immunohistochemistry revealed an apparent increase in the ARC Kiss1 mRNA expression and kisspeptin immunoreactivity around the time of vaginal opening in intact female rats. The AVPV Kiss1 mRNA levels also increased at day 26, but decreased at day 31, and then increased at day 36/41. In ovariectomised (OVX) rats, ARC Kiss1 mRNA expression did not show peripubertal changes and was kept at a high level throughout peripubertal periods. Apparent LH pulses were found in these prepubertal OVX rats. Oestradiol replacement suppressed ARC Kiss1 mRNA expression in OVX prepubertal rats, but not in adults. Similarly, LH pulses were suppressed by oestradiol in the prepubertal period (days 21 and 26), but regular pulses were found in adulthood. The present study suggests that a pubertal increase of Kiss1/kisspeptin expression both in the ARC and AVPV is involved in the onset of puberty. These results also suggest that both LH pulses and ARC Kiss1 expression are more negatively regulated by oestrogen in prepubertal female rats compared to adult rats. [source] Altered Expression of SOCS3 in the Hypothalamic Arcuate Nucleus during Seasonal Body Mass Changes in the Field Vole, Microtus agrestisJOURNAL OF NEUROENDOCRINOLOGY, Issue 2 2007E. Król We have previously shown that cold-acclimated (8 °C) male field voles (Microtus agrestis) transferred from short day (SD, 8 h light) to long day (LD, 16 h light) photoperiod exhibit an increase in body mass lasting 4 weeks, after which they stabilise at a new plateau approximately 7.5 g (24.8%) higher than animals maintained in SD. By infusing voles with exogenous leptin, we have also demonstrated that SD voles respond to the hormone by reducing body mass and food intake, whereas LD animals increasing body mass are resistant to leptin treatment. In the present study, we investigated whether seasonal changes in body mass could be linked to modulation of the leptin signal by suppressor of cytokine signalling-3 (SOCS3). We used in situ hybridisation to examine hypothalamic arcuate nucleus (ARC) expression of SOCS3, neuropeptide Y (NPY), agouti-related peptide (AgRP), pro-opiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART) genes in 90 voles exposed to either SD or LD for up to 11 weeks. LD voles increasing body mass had significantly higher levels of SOCS3 mRNA than SD or LD voles with a stable body mass. There were no associated changes in expression of NPY, AgRP, POMC and CART genes. These results suggest that voles that regulate body mass at either the lower (SD) or upper (LD) plateau remain sensitive to leptin action, whereas SOCS3-mediated leptin resistance is a short-term mechanism that enables animals to move between the stable body mass plateaus. Our data provide evidence that expression of SOCS3 in the ARC is involved in the modulation of the strength of the leptin signal to facilitate seasonal cycles in body mass and adiposity. [source] Elevated KiSS-1 Expression in the Arcuate Nucleus Prior to the Cyclic Preovulatory Gonadotrophin-Releasing Hormone/Lutenising Hormone Surge in the Ewe Suggests a Stimulatory Role for Kisspeptin in Oestrogen-Positive FeedbackJOURNAL OF NEUROENDOCRINOLOGY, Issue 10 2006K. M. Estrada Kisspeptins are encoded by the gene KiSS-1 and regulate gonadotrophin-releasing hormone (GnRH) and gonadotrophin secretion in various species, including humans. Here, we quantify gene expression of KiSS-1 in the arcuate nucleus (ARC) across the ovine oestrous cycle and demonstrate an increase in the caudal division of the ARC during the preovulatory period. These data strongly suggest that kisspeptins are involved in the generation of the preovulatory GnRH and luteinising hormone surge. [source] Matrix metalloproteinase-7, -8, -9, -25, and -26 and CD43, -45, and -68 cell-markers in HIV-infected patients' saliva and gingival tissueJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 9 2006Liisa Mellanen Background:, Matrix metalloproteinases (MMPs) process the extracellular matrix and act in tissue remodelling in many physiological and pathological conditions. Certain MMPs can also exert protective anti-inflammatory properties. The levels and expression of MMPs and tissue inhibitors of MMPs (TIMPs) in saliva and gingival tissues of human immunodeficiency virus-seropositive (HIV+) patients are unclear. Methods:, Enzyme-linked immunosorbent assay methods and Western blots were used to study levels and molecular forms of MMP-7, -8, -9, -25, and -26 and TIMP-1 from salivary samples of HIV+ patients (n = 55) and healthy controls (n = 10). The expression of MMPs was also studied by immunohistochemical means in gingival tissue specimens (n = 11, HIV+ patients; n = 10, healthy controls). Results:, The HIV+ patients' MMP-8 levels in saliva were statistically significantly higher only in the acquired immunodeficiency syndrome (AIDS)-phase. MMP-9 levels in ASX- and AIDS-phases showed increased expression. TIMP-1 levels were significantly decreased in lymphadenopathy syndrome (LAS)- and AIDS-related complex (ARC)-phases, while MMP-8/TIMP-1 and MMP-9/TIMP-1 molar ratios were increased in all phases in comparison with controls. The molecular forms of MMP-7, -25, and -26 were different between patients and controls as assessed by Western blot. Immunohistochemical studies showed slightly enhanced MMP-7, -8, -9, -25, and -26 staining in HIV+ gingival tissue samples in comparison with controls. Conclusions:, This study confirmed and further demonstrated differences in salivary amounts and molecular forms of MMPs and TIMP-1 in HIV+ patients. The results may reflect alterations in host defence reactions associated with HIV infection. [source] Ethanol-Induced Increase of Agouti-Related Protein (AgRP) Immunoreactivity in the Arcuate Nucleus of the Hypothalamus of C57BL/6J, but not 129/SvJ, Inbred MiceALCOHOLISM, Issue 4 2010Inmaculada Cubero Background:, The melanocortin (MC) system is composed of peptides that are cleaved from the polypeptide precursor, pro-opiomelanocortin (POMC). Previous research has shown that MC receptor (MCR) agonists reduce, and MCR antagonists increase, ethanol consumption in rats and mice. Consistently, genetic deletion of the endogenous MCR antagonist, agouti-related protein (AgRP), causes reductions of ethanol-reinforced lever pressing and binge-like ethanol drinking in C57BL/6J mice. Ethanol also has direct effects on the central MC system, as chronic exposure to an ethanol-containing diet causes significant reductions of ,-melanocyte stimulating hormone (,-MSH) immunoreactivity in specific brain regions of Sprague-Dawley rats. Together, these observations suggest that the central MC system modulates neurobiological responses to ethanol. To further characterize the role of the MC system in responses to ethanol, here we compared AgRP and ,-MSH immunoreactivity in response to an acute injection of saline or ethanol between high ethanol drinking C57BL/6J mice and moderate ethanol drinking 129/SvJ mice. Methods:, Mice received an intraperitoneal (i.p.) injection of ethanol (1.5 g/kg or 3.5 g/kg; mixed in 0.9% saline) or an equivolume of 0.9% saline. Two hours after injection, animals were sacrificed and their brains were processed for AgRP and ,-MSH immunoreactivity. Results:, Results indicated that acute ethanol administration triggered a dose-dependent increase in AgRP immunoreactivity in the arcuate (ARC) of C57BL/6J mice, an effect that was not evident in the 129/SvJ strain. Although acute administration of ethanol did not influence ,-MSH immunoreactivity, C57BL/6J mice had significantly greater overall ,-MSH immunoreactivity in the ARC, dorsomedial, and lateral regions of the hypothalamus relative to the 129/SvJ strain. In contrast, C57BL/6J mice displayed significantly lower ,-MSH immunoreactivity in the medial amygdala. Conclusions:, The results show that acute ethanol exposure has direct effects on endogenous AgRP activity in ethanol preferring C57BL/6J mice. It is suggested that ethanol-induced increases in AgRP may be part of a positive feedback system that stimulates excessive binge-like ethanol drinking in C57BL/6J mice. Inherent differences in ,-MSH immunoreactivity may contribute to differences in neurobiological responses to ethanol that are characteristically observed between the C57BL/6J and 129/SvJ inbred strains of mice. [source] Short-Term Alcohol Administration Alters KiSS-1 Gene Expression in the Reproductive Hypothalamus of Prepubertal Female RatsALCOHOLISM, Issue 9 2009Vinod K. Srivastava Background:, Kisspeptins bind to the G-protein-coupled receptor (GPR54) to activate hypothalamic luteinizing hormone releasing hormone (LHRH) secretion at the time of puberty. Alcohol (ALC) causes depressed prepubertal LHRH release, resulting in depressed luteinizing hormone (LH) secretion and delayed puberty. Because KiSS-1 and GPR54 are important to the onset of puberty, we assessed the effects of chronic ALC administration on basal expression of these puberty-related genes within the reproductive hypothalamus, as well as hormones and transduction signaling pathways contributing to their activity. Methods:, Immature female rats were fed a liquid diet containing ALC for 6 days beginning when 27 days old. Controls received either companion isocaloric liquid diet or rat chow and water. Animals were decapitated on day 33, in the late juvenile stage of development. Blood was collected for the assessment of serum hormone levels. Brain tissues containing the anteroventral periventricular (AVPV) and arcuate (ARC) nuclei were obtained for assessing expression of specific puberty-related genes and proteins. Results:,KiSS-1 mRNA levels in the AVPV and ARC nuclei were suppressed (p < 0.001) in the ALC-treated rats. GPR54 gene and protein expressions were both modestly increased (p < 0.05) in AVPV nucleus, but not in ARC nucleus. Alcohol exposure also resulted in suppressed serum levels of insulin-like growth factor-1 (IGF-1), LH, and estradiol (E2). As IGF-1, in the presence of E2, can induce expression of the KiSS-1 gene, we assessed the potential for ALC to alter IGF-1 signaling in the reproductive hypothalamus. IGF-1 receptor gene and protein expressions were not altered. However, protein expression of phosphorylated Akt, a transduction signal used by IGF-1, was suppressed in the AVPV (p < 0.05) and ARC (p < 0.01) nuclei. Conclusions:, Alcohol causes suppressed KiSS-1 gene expression in the reproductive hypothalamus; hence, contributing to this drug's ability to cause suppressed LHRH secretion and disruption of the pubertal process. We suggest that this action, at least in part, is through altered IGF-1 signaling. [source] Flexural Strength, Elastic Modulus, and pH Profile of Self-etch Resin Luting CementsJOURNAL OF PROSTHODONTICS, Issue 4 2008Egle Saskalauskaite DDS Abstract Purpose: To determine the flexural strength, modulus of elasticity, and 24-hour pH profile of three self-etching resin luting cements and to obtain comparative data for representative conventional resin and resin-modified glass ionomer luting cements. Materials and Methods: Three self-etching resin luting cements [RelyX Unicem (3M ESPE), Maxcem (Kerr), Embrace Wetbond (Pulpdent)] were tested and compared with two conventional resin cements [RelyX ARC (3M ESPE), Linkmax (GC)] plus two resin-modified glass ionomer luting cements [Fuji Plus (GC), RelyX Luting Plus (3M ESPE)]. Flexural strength and modulus of elasticity were determined using bar-shaped specimens (2 × 2 × 25 mm3) at 24 hours, using an Instron universal testing machine. Setting pH was measured using a flat-surface pH electrode at 0, 2, 5, 15, and 30 minutes and 1, 2, 4, 6, and 24 hours after mixing. Testing was performed under both dual-cured and self-cured conditions for all dual-cure cements. Data analysis included ANOVA and Tukey's test (p < 0.05). Results: The self-etching cements showed similar flexural strength to the conventional resin cements, except for Embrace Wetbond self-cured, which was considerably lower. Modulus of elasticity results were both higher and lower than for conventional resin cements. All photopolymerized conventional and self-etch dual-cure cements showed markedly higher flexural strength and modulus than when solely self-cured. The resin-modified glass ionomer cements were characterized by lower flexural strength and elastic modulus. Self-etching resin cements showed lower initial pH (2.0 to 2.4) than conventional resin cements (4.8 to 5.2) and a wide range of final pH values (3.9 to 7.3) at 24 hours. One self-etching cement (Unicem) revealed a unique pH profile characterized by a more rapid rise in pH to neutrality both when dual-cured (15 minutes) and when auto-cured (1 hour). Conclusions: The self-etching resin cements evaluated in this study displayed disparate properties and cannot be considered a homogeneous group. Flexural strength properties were most uniform and were similar to those of the conventional resin cements, whereas moduli of elasticity showed greater variation. Setting pH profiles differed, depending on the brand and mode of cure, even within the same category of luting cement. All cements with dual-cure capability, both conventional and self-etch, showed significantly superior properties when photopolymerized. [source] Clinical Efficacy and Safety of Recombinant Canine Erythropoietin in Dogs with Anemia of Chronic Renal Failure and Dogs with Recombinant Human Erythropoietin-Induced Red Cell AplasiaJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 1 2004John F. Randolph The efficacy and safety of recombinant canine erythropoietin (rcEPO) therapy was evaluated in 19 dogs with anemia of chronic renal failure (group 1) and 6 dogs with chronic renal failure and recombinant human erythropoietin (rhEPO)-induced red cell aplasia (group 2). Hematocrit (Hct) and absolute reticulocyte count (ARC) were monitored weekly for the first 8 weeks, CBC (including ARC) and serum iron profiles were evaluated monthly, and serum biochemical analyses were performed every 2 months for 6 (group 2) to 12 (group 1) months. For group 1 dogs, median Hct and ARC increased significantly during the 1st week of rcEPO treatment, and median Hct was sustained at >35% after week 5. In contrast, median Hct and ARC for group 2 did not change significantly with rcEPO treatment, even with doses greater than those used in group 1. Nevertheless, 2 (33%) of the 6 dogs in group 2 developed erythroid hyperplasia, reticulocytosis, and increases in Hct with rcEPO treatment. Although median systolic blood pressure did not change significantly in either group, 5 dogs developed systolic blood pressures a 180 mm Hg during the study. Appetite and energy level improved in most group 1 dogs with increases in Hct. Recombinant cEPO stimulated erythrocyte production in dogs with nonregenerative anemia secondary to chronic renal failure without causing the profound erythroid hypoplasia that can occur in rhEPO-treated dogs. Unfortunately, rcEPO was not as effective in restoring erythrocyte production in dogs that had previously developed rhEPO-induced red cell aplasia. [source] Apodization of fiber Bragg gratings by using ARC dischargesMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 2 2008R. Romero Abstract The electric arc technique is used to apodize fiber Bragg gratings (FBGs). Arc discharges applied to the ends of the grating produce a smoothing of the refractive-index modulation profile reducing the sidelobes of the reflection spectrum at longer wavelengths. A sidelobe reduction of 17 dB was obtained. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 316,319, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23056 [source] Allergy related disorders among 2-yrs olds in a general population.PEDIATRIC ALLERGY AND IMMUNOLOGY, Issue 2p1 2010The PACT Study Smidesang I, Saunes M, Storrø O, Øien T, Holmen TL, Johnsen R, Henriksen AH. Allergy related disorders among 2-yrs olds in a general population. The PACT Study. Pediatr Allergy Immunol 2010: 21: 315,320. © 2009 John Wiley & Sons A/S Allergic disorders represent a major health problem in most developed countries, but few population-based studies have focused on these disorders in early childhood. The aims of the present study were to investigate the prevalence, gender differences and distribution of allergy related disorders and their association to sensitization among unselected children, 2 yrs of age, in a general population. A population-based study with parental self reported questionnaire data involving allergy related symptoms and results from allergy tests from 4783 two-yr-old children was conducted, and skin prick tests (SPT) of a randomly selected sample comprising 390 children were performed. In the total population the prevalence of reported wheeze was 26%, doctor diagnosed asthma (DDAsthma) 7.0%, atopic dermatitis (AD) 17% and allergic rhinoconjunctivitis (ARC) 3%. Of the 1008 (21%) allergy tested children 59% reported a positive test, but of the randomly selected children only 8% had a positive SPT. Children with AD were most frequently sensitized and children with ARC were most likely to have other allergy related disorders (70%). More boys than girls had an allergy related disorder or a positive allergy test. In conclusion, two in five had an allergy related disorder, but less than 10% had a positive SPT. Having one allergic disorder, especially ARC, increased substantially the risk of having another, and having AD was most strongly associated to a positive allergy test. Moreover, boys were more likely than girls to have an allergy related disorder or a positive SPT indicating a gender difference in the natural history of allergy related disorders. [source] Mechanical and Tribological Properties of Cr-DLC Coatings Deposited by ARC-MAG-RF PACVD Hybrid MethodPLASMA PROCESSES AND POLYMERS, Issue S1 2007Andrzej Czyzniewski Abstract The procedure of Cr-DLC coating deposition using a hybrid ARC-MAG-RF PACVD method is presented in this paper. ARC and MAG techniques were used to deposit a Cr/Cr-C:H interlayer with increasing hardness, but a nearly constant elastic modulus of the value similar to a steel substrate and DLC layer deposited then by RF PACVD technique. As a result of such coating formation the lower level of stresses in the coating-substrate system, both intrinsic and induced by the load applied, was obtained. The resultant Cr-DLC coating is marked by high crack resistance and high adhesion. The Cr-DLC coating shows high wear resistance, but the wear geometry and the friction coefficient depend on a type of the counterpart material. [source] Hazard ratings for organic peroxidesPROCESS SAFETY PROGRESS, Issue 2 2008Yih-Shing Duh Abstract Nine of commercially available organic peroxides were assessed with differential scanning calorimeter (DSC) and adiabatic calorimeters. These organic peroxides are cumene hydroperoxide (CHP), di- tert -butyl peroxide (DTBP), methyl-ethyl-ketone peroxide (MEKPO), tert -butyl hydroperoxide (TBHP), benzoyl peroxide (BPO), hydrogen peroxide, lauroyl peroxide (LPO), tert -butyl peroxybenzoate (TBPBZ), and dicumyl peroxide (DCPO). Exothermic onset temperatures, self-heat temperature and pressure rates, and heats of decomposition were measured and assessed. Adiabatic runaway reaction characteristics were determined by using ARC (accelerating rate calorimeter) and VSP2 (vent sizing package). Incompatibility, tests with several potential contaminants, was made using DSC, VSP2, and microcalorimeter. An incompatibility rating was developed using onset temperature, lowering of the onset temperature, heat of decomposition, maximum self-heat rate, adiabatic temperature rise, maximum pressure of decomposition, and maximum pressure rising rate, etc. © 2008 American Institute of Chemical Engineers Process Saf Prog 2008 [source] Toxic gas release caused by the thermal decomposition of a bulk powder blend containing sodium dichloroisocyanuratePROCESS SAFETY PROGRESS, Issue 2 2003Andrew R. Carpenter P.E. A thermal runaway reaction occurred during the mixing of a batch of a bulk powder that resulted in the production and release of toxic gases. The mixture consisted of an oxidizer (sodium dichloroisocyanurate), some organic compounds, and inert compounds. This toxic release led to the evacuation of the building and resulted in extensive damage to the facility. This was only the fourth time an 1,100-pound batch of this material had been mixed in this equipment. Prior to this production run, the material had been prepared in small batches of 2 to 50 kilograms. Accelerated Rate Calorimetry (ARC) testing had been performed prior to the scale-up to production batches. This paper looks into the root causes of this particular accident and demonstrates how proper analysis of the testing data and other warning signs observed during the bench testing could have revealed the likelihood of this accident. Further, this paper will consider how simple design changes to the manufacturing process resulted in an inherently safer design. [source] Dry phosphorus silicate glass etching for multicrystalline silicon solar cellsPROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 7 2003W. A. Nositschka Abstract A dry plasma etching process for phosphorus silicate glass (PSG) in a SiN-PECVD batch reactor is developed. In the same reactor PSG etching and anti-reflective coating (ARC) can be performed successively. To demonstrate industrial feasibility, screen-printed solar cells are manufactured and compared with cells prepared by a standard wet chemical process. Copyright © 2003 John Wiley & Sons, Ltd. [source] Agonist activation of arachidonate-regulated Ca2+ -selective (ARC) channels in murine parotid and pancreatic acinar cellsTHE JOURNAL OF PHYSIOLOGY, Issue 3 2005Olivier Mignen ARC channels (arachidonate-regulated Ca2+ -selective channels) are a novel type of highly Ca2+ -selective channel that are specifically activated by low concentrations of agonist-induced arachidonic acid. This activation occurs in the absence of any depletion of internal Ca2+ stores (i.e. they are ,non-capacitative'). Previous studies in HEK293 cells have shown that these channels provide the predominant pathway for the entry of Ca2+ seen at low agonist concentrations where oscillatory [Ca2+]i signals are typically produced. In contrast, activation of the more widely studied store-operated Ca2+ channels (e.g. CRAC channels) is only seen at higher agonist concentrations where sustained ,plateau-type'[Ca2+]i responses are observed. We have now demonstrated the presence of ARC channels in both parotid and pancreatic acinar cells and shown that, again, they are specifically activated by the low concentrations of appropriate agonists (carbachol in the parotid, and both carbachol and cholecystokinin in the pancreas) that are associated with oscillatory [Ca2+]i signals in these cells. Uncoupling the receptor-mediated activation of cytosolic phospholipase A2 (cPLA2) with isotetrandrine reduces the activation of the ARC channels by carbachol and, correspondingly, markedly inhibits the [Ca2+]i signals induced by low carbachol concentrations, whilst those signals seen at high agonist concentrations are essentially unaffected. Interestingly, in the pancreatic acinar cells, activation by cholecystokinin induces a current through the ARC channels that is only approximately 60% of that seen with carbachol. This is consistent with previous reports indicating that carbachol-induced [Ca2+]i signals in these cells are much more dependent on Ca2+ entry than are the cholecystokinin-induced responses. [source] New potential anti-cancer agents synergize with bortezomib and ABT-737 against prostate cancerTHE PROSTATE, Issue 8 2010Bulbul Pandit Abstract BACKGROUND We previously described the identification of a transcriptional inhibitor ARC and FoxM1 inhibitors, thiazole antibiotics, Siomycin A and thiostrepton that were able to induce potent p53-independent apoptosis in cancer cell lines of different origin. Here, we report the characterization of these drugs individually or in combination with ABT-737 and bortezomib on a panel of prostate cancer cell lines. METHODS DU 145, LNCaP and PC-3 prostate cancer cells were treated with ARC, Siomycin A and thiostrepton to evaluate their activity as single agents or in combination with ABT-737 and bortezomib to measure their synergistic potential in anti-proliferative and cell cycle assays. Chou-Talalay method was used to quantitate the synergistic interaction. Western blot method was used to determine Mcl-1 and FoxM1 expression and caspase-3 cleavage. RESULTS We show that ARC inhibited the viability of prostate cancer cells and induced apoptosis in low nanomolar concentration. It potently downregulated the expression of Mcl-1 and showed synergistic combination effect with Bcl-2 inhibitor ABT-737. Thiazole antibiotics, Siomycin A and thiostrepton inhibited growth, FoxM1 expression and induced cell death in prostate cancer cells in low micromolar concentrations. In addition, thiostrepton and ARC synergistically induced apoptosis in prostate cancer cells following combination treatment with proteasome inhibitor bortezomib. Furthermore, we found that all tested drug combinations were able to induce apoptosis selectively in transformed, but not normal cells of the same origin. CONCLUSIONS Based on their in vitro activity as single or combination agents, ARC, Siomycin A and thiostrepton represent potential candidates for drug development against prostate cancer. Prostate 70: 825,833, 2010. © 2010 Wiley-Liss, Inc. [source] Neural Network Adaptive Robust Control Of Siso Nonlinear Systems In A Normal FormASIAN JOURNAL OF CONTROL, Issue 2 2001J.Q. Gong ABSTRACT In this paper, performance oriented control laws are synthesized for a class of single-input-single-output (SISO) n -th order nonlinear systems in a normal form by integrating the neural networks (NNs) techniques and the adaptive robust control (ARC) design philosophy. All unknown but repeat-able nonlinear functions in the system are approximated by the outputs of NNs to achieve a better model compensation for an improved performance. While all NN weights are tuned on-line, discontinuous projections with fictitious bounds are used in the tuning law to achieve a controlled learning. Robust control terms are then constructed to attenuate model uncertainties for a guaranteed output tracking transient performance and a guaranteed final tracking accuracy. Furthermore, if the unknown nonlinear functions are in the functional ranges of the NNs and the ideal NN weights fall within the fictitious bounds, asymptotic output tracking is achieved to retain the perfect learning capability of NNs. The precision motion control of a linear motor drive system is used as a case study to illustrate the proposed NNARC strategy. [source] | ||||||||||||||||||||||||||||||||||||||||||||||||||||