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Sample records for regional vasoconstriction underlying

  1. Vasoconstriction

    MedlinePlus

    Vasoconstriction is the narrowing (constriction) of blood vessels by small muscles in their walls. When blood vessels constrict, blood flow is slowed or blocked. Vasoconstriction may be slight or severe. It may result ...

  2. Reversible cerebral vasoconstriction syndrome: an under-recognized clinical emergency

    PubMed Central

    Chen, Shih-Pin; Fuh, Jong-Ling; Wang, Shuu-Jiun

    2010-01-01

    Reversible cerebral vasoconstriction syndrome (RCVS) is characterized by recurrent thunderclap headaches and reversible cerebral vasoconstrictions. RCVS is more common than previously thought and should be differentiated from aneurismal subarachnoid hemorrhage. RCVS can be spontaneous or evoked by pregnancy or exposure to vasoactive substances. Patients tend to be middle-aged women but pediatric patients have been seen. Up to 80% of sufferers have identifiable triggers. Thunderclap headaches tend to recur daily and last for a period of around 2 weeks, while the vasoconstrictions may last for months. About one-third of patients have blood pressure surges accompanying headache attacks. The potential complications of RCVS include posterior reversible encephalopathy syndrome, ischemic strokes over watershed zones, cortical subarachnoid hemorrhage and intracerebral hemorrhage. Magnetic resonance images including angiography and venography and lumbar punctures are the studies of choice, whereas catheter angiography should not be implemented routinely. Patients with a mean flow velocity of the middle cerebral artery greater than 120 cm/s shown by transcranial color-coded sonography have a greater risk of ischemic complications than those without. The pathophysiology of RCVS remains unknown; sympathetic hyperactivity may play a role. Open-label trials showed calcium channel blockers, such as nimodipine may be an effective treatment in prevention of thunderclap headache attacks. In severe cases, intra-arterial therapy may be considered. Most patients with RCVS recover without sequelae; however, relapse has been reported in a small proportion of patients. PMID:21179608

  3. Hypoxic Pulmonary Vasoconstriction in Humans

    PubMed Central

    Loubani, Mahmoud; Morice, Alyn H.

    2013-01-01

    Hypoxic pulmonary vasoconstriction is the elegant theory put forward more than six decades ago to explain regional variations in perfusion within the lung in certain animal species in response to localised restrictions in oxygenation. Although considerable progress has been made to describe the phenomenon at the macroscopic level and explain it at the microscopic level, we are far from a universal agreement about the process in humans. This review attempts to highlight some of the important evidence bases of hypoxic pulmonary vasoconstriction in humans and the significant gaps in our knowledge that would need bridging. PMID:24024204

  4. CFTR and sphingolipids mediate hypoxic pulmonary vasoconstriction.

    PubMed

    Tabeling, Christoph; Yu, Hanpo; Wang, Liming; Ranke, Hannes; Goldenberg, Neil M; Zabini, Diana; Noe, Elena; Krauszman, Adrienn; Gutbier, Birgitt; Yin, Jun; Schaefer, Michael; Arenz, Christoph; Hocke, Andreas C; Suttorp, Norbert; Proia, Richard L; Witzenrath, Martin; Kuebler, Wolfgang M

    2015-03-31

    Hypoxic pulmonary vasoconstriction (HPV) optimizes pulmonary ventilation-perfusion matching in regional hypoxia, but promotes pulmonary hypertension in global hypoxia. Ventilation-perfusion mismatch is a major cause of hypoxemia in cystic fibrosis. We hypothesized that cystic fibrosis transmembrane conductance regulator (CFTR) may be critical in HPV, potentially by modulating the response to sphingolipids as mediators of HPV. HPV and ventilation-perfusion mismatch were analyzed in isolated mouse lungs or in vivo. Ca(2+) mobilization and transient receptor potential canonical 6 (TRPC6) translocation were studied in human pulmonary (PASMCs) or coronary (CASMCs) artery smooth muscle cells. CFTR inhibition or deficiency diminished HPV and aggravated ventilation-perfusion mismatch. In PASMCs, hypoxia caused CFTR to interact with TRPC6, whereas CFTR inhibition attenuated hypoxia-induced TRPC6 translocation to caveolae and Ca(2+) mobilization. Ca(2+) mobilization by sphingosine-1-phosphate (S1P) was also attenuated by CFTR inhibition in PASMCs, but amplified in CASMCs. Inhibition of neutral sphingomyelinase (nSMase) blocked HPV, whereas exogenous nSMase caused TRPC6 translocation and vasoconstriction that were blocked by CFTR inhibition. nSMase- and hypoxia-induced vasoconstriction, yet not TRPC6 translocation, were blocked by inhibition or deficiency of sphingosine kinase 1 (SphK1) or antagonism of S1P receptors 2 and 4 (S1P2/4). S1P and nSMase had synergistic effects on pulmonary vasoconstriction that involved TRPC6, phospholipase C, and rho kinase. Our findings demonstrate a central role of CFTR and sphingolipids in HPV. Upon hypoxia, nSMase triggers TRPC6 translocation, which requires its interaction with CFTR. Concomitant SphK1-dependent formation of S1P and activation of S1P2/4 result in phospholipase C-mediated TRPC6 and rho kinase activation, which conjointly trigger vasoconstriction. PMID:25829545

  5. CFTR and sphingolipids mediate hypoxic pulmonary vasoconstriction

    PubMed Central

    Tabeling, Christoph; Yu, Hanpo; Wang, Liming; Ranke, Hannes; Goldenberg, Neil M.; Zabini, Diana; Noe, Elena; Krauszman, Adrienn; Gutbier, Birgitt; Yin, Jun; Schaefer, Michael; Arenz, Christoph; Hocke, Andreas C.; Suttorp, Norbert; Proia, Richard L.; Witzenrath, Martin; Kuebler, Wolfgang M.

    2015-01-01

    Hypoxic pulmonary vasoconstriction (HPV) optimizes pulmonary ventilation-perfusion matching in regional hypoxia, but promotes pulmonary hypertension in global hypoxia. Ventilation-perfusion mismatch is a major cause of hypoxemia in cystic fibrosis. We hypothesized that cystic fibrosis transmembrane conductance regulator (CFTR) may be critical in HPV, potentially by modulating the response to sphingolipids as mediators of HPV. HPV and ventilation-perfusion mismatch were analyzed in isolated mouse lungs or in vivo. Ca2+ mobilization and transient receptor potential canonical 6 (TRPC6) translocation were studied in human pulmonary (PASMCs) or coronary (CASMCs) artery smooth muscle cells. CFTR inhibition or deficiency diminished HPV and aggravated ventilation-perfusion mismatch. In PASMCs, hypoxia caused CFTR to interact with TRPC6, whereas CFTR inhibition attenuated hypoxia-induced TRPC6 translocation to caveolae and Ca2+ mobilization. Ca2+ mobilization by sphingosine-1-phosphate (S1P) was also attenuated by CFTR inhibition in PASMCs, but amplified in CASMCs. Inhibition of neutral sphingomyelinase (nSMase) blocked HPV, whereas exogenous nSMase caused TRPC6 translocation and vasoconstriction that were blocked by CFTR inhibition. nSMase- and hypoxia-induced vasoconstriction, yet not TRPC6 translocation, were blocked by inhibition or deficiency of sphingosine kinase 1 (SphK1) or antagonism of S1P receptors 2 and 4 (S1P2/4). S1P and nSMase had synergistic effects on pulmonary vasoconstriction that involved TRPC6, phospholipase C, and rho kinase. Our findings demonstrate a central role of CFTR and sphingolipids in HPV. Upon hypoxia, nSMase triggers TRPC6 translocation, which requires its interaction with CFTR. Concomitant SphK1-dependent formation of S1P and activation of S1P2/4 result in phospholipase C-mediated TRPC6 and rho kinase activation, which conjointly trigger vasoconstriction. PMID:25829545

  6. Pulmonary hypoxic vasoconstriction: how strong? How fast?

    NASA Technical Reports Server (NTRS)

    Sheehan, D. W.; Klocke, R. A.; Farhi, L. E.

    1992-01-01

    We have developed a minimally invasive technique for studying regional blood flow in conscious sheep, bypassing the complications of open-chest surgery, flow probes and tracer infusion. We quantitate regional perfusion continuously on the basis of regional clearance of methane (methane is produced in the sheep rumen, enters the circulation and is eliminated nearly completely (greater than 95%) in the lung). Tracheal intubation with a dual-lumen catheter isolates the gas exchange of the right apical lobe (RAL; less than 15% of the lung) from that of the remainder of the lung, which serves as a control (CL). We measure RAL and CL methane elimination by entraining expirates in constant flows, sampled continuously for methane. Results obtained with this technique and from regional oxygen uptake are in excellent agreement. We have found that hypoxic vasoconstriction is far more potent and stable during eucapnic hypoxia than during hypocapnic hypoxia. The time course of the vasoconstriction suggests that many of the data in the literature may have been obtained prior to steady state.

  7. Nitric oxide inhibition sustains vasopressin-induced vasoconstriction.

    PubMed Central

    Dworkin, M. J.; Carnochan, P.; Allen-Mersh, T. G.

    1995-01-01

    Hepatic parenchymal vasoconstriction increases cytotoxic drug uptake into hepatic metastases by increasing the tumour to liver blood flow ratio. Prolonged infusion of the vasoconstrictor vasopressin does not result in sustained vasoconstriction, and this may limit the benefit of vasopressin in infusional chemotherapy. We have assessed whether loss of vasopressin-induced vasoconstriction is mediated by nitric oxide. Hepatic and tumour blood flow were continuously monitored, in an animal hepatic tumour model, by laser Doppler flowmetry. The response to regionally infused vasopressin and the nitric oxide inhibitor N-nitro-L-arginine methyl ester (L-NAME) were assessed over a 30 min infusion period. The vasopressin-induced vasoconstrictor effect diminished after 15 min despite continued infusion. Vasoconstriction was significantly prolonged when L-NAME was infused in addition to vasopressin. The increase in tumour to normal blood flow ratio was greater over the infusion period when L-NAME was co-administered with vasopressin. Our results suggest that the loss of vasopressin-induced vasoconstriction seen in liver parenchyma after regional infusion is prevented by the nitric oxide synthase inhibitor L-name and may be mediated by nitric oxide. PMID:7734317

  8. Cocaine attenuates vasoconstriction to ethanol

    SciTech Connect

    Bove, A.A.; Morley, D.; Vosacek, R.; Zhang, X.Y.; Shah, R. )

    1991-03-11

    The purpose of this study was to determine the combined effects of cocaine and ethanol on vasomotor tone. Using a standard isolated vascular ring preparation, 24 rings from 7 New Zealand White Rabbits were studied. All rings were denuded as verified by methacholine challenge. The dose response to NE for each ring was used as a standard for vasoconstrictors Dose response curves to ETH and C were done in random order. Concentrations of both ETH and C employed were physiologically attainable in man and below thresholds for coma or death. The dose response curve to ETH was repeated after addition of 4 {times} 10{sup {minus}5} M C to the arterial bath. After adding 1,500 ug/ml of ETH, the dose response curve to C was repeated. Ethanol, alone caused significant vasoconstriction of arterial rings. After the addition of C to the bath, the dose response to ETH was significantly shifted to the right, peak contraction achieved was 36.6 {plus minus} 3.2% of maximal NE contraction. Cocaine alone did not result in any change in resting tension of the rings. When ETH was added to the bath, C caused vasoconstriction, the peak value equivalent to 12.5 {plus minus} 2.2% of maximal contraction to NE.

  9. Modeling of deep breath vasoconstriction reflex.

    PubMed

    Chalacheva, Patjanaporn; Khoo, Michael C K

    2015-08-01

    Deep breaths akin to sighs have been reported to cause peripheral vasoconstriction. Our previous simulation studies have shown that this phenomenon cannot be reproduced in existing circulatory control models without inclusion of a respiratory-vascular coupling mechanism. To better understand this "sigh-vasoconstriction reflex", we investigated the effect of spontaneous and passively induced sighs as well as spontaneous breathing on peripheral vasoconstriction during wakefulness and non-rapid eye movement sleep in human subjects. We found that both spontaneous and induced sighs caused vasoconstriction during wakefulness and sleep. The coupling between respiration and vasoconstriction is also present even in an absence of deep breaths. The coupling mechanism is largely linear with increased nonlinearity during induced sighs. Since peripheral vascular resistance modulation is known to be sympathetically mediated, investigation of this coupling could potentially allow us to assess sympathetic function through non-invasive measurements and simple interventions. PMID:26738099

  10. Perfusion of nonventilated lung: failure of hypoxic vasoconstriction

    SciTech Connect

    Sostman, H.D.; Neumann, R.D.; Gottschalk, A.; Greenspan, R.H.

    1983-07-01

    Alveolar hypoxia is a well established cause of regional vasoconstriction such that nonventilated segments are not perfused. The paradoxical situation of retained perfusion of nonventilated lung has seldom been discussed. Three clinical examples are illustrated. In each case coexistent chronic obstructive lung disease may have contributed to this unexpected finding by reducing pulmonary vascular capacity such that blood flow diversion from hypoxic segments was not possible.

  11. Estimation of endothelin-mediated vasoconstriction in acute pulmonary thromboembolism

    PubMed Central

    Tsang, John Y. C.; Lamm, Wayne J. E.

    2012-01-01

    We aimed to investigate the role of endothelin-mediated vasoconstriction following acute pulmonary thromboembolism (APTE). Thirteen anesthetized piglets (~25 kg) were ventilated with 0 PEEP. Cardiac output (Qt) and wedge pressure (Pw) were measured by a Swan Ganz catheter, along with arterial and venous blood gases. APTE was induced by autologous blood clots (~0.8 g/kg, 12-16 pieces) via a jugular venous catheter at time = 0 minutes until the mean pulmonary arterial pressure (Ppa) was about 2.5 times the baseline at 30 minutes. Eight control animals (Group 1) received only normal saline afterward, while the remaining five (Group 2) received at time = 40-minute saline plus Tezosentan, a nonspecific endothelin antagonist. The drug was initially given as an intravenous bolus (10 mg/kg), followed by an infusion (2 mg/min) until the end of the experiment at 2 hours. Hemodynamic data were measured before APTE and then at 30-minute intervals. Pulmonary vascular resistance index (PVRI) was calculated as (Ppa-Pw)/CI, where CI was cardiac index or Qt/W (body weight). Fluorescent microspheres (FMS) were used to mark regional blood flows and ventilation for cluster analysis. PVRI acutely increased within minutes and remained high despite some recovery over time. With Tezosentan treatment, the results showed that endothelin-mediated vasoconstriction persisted significantly up to 2 hours and accounted for about 25% of the increase in PVRI while clot obstruction accounted for the remaining 75%. CI remained relatively constant throughout. Tezosentan also affected PVRI indirectly by mitigating the shift of regional blood flow back to the embolized areas over time, possibly by attenuating vasoconstriction in the nonembolized areas. We conclude that following APTE, although the increased PVRI is mostly due to mechanical embolic obstruction, secondary factors such as vasoconstriction and pattern of regional blood flow over time also play important roles. PMID:22558522

  12. Measurement of model coefficients of skin sympathetic vasoconstriction.

    PubMed

    Severens, Natascha M W; van Marken Lichtenbelt, Wouter D; Frijns, Arjan J H; Kingma, Boris R M; de Mol, Bas A J M; van Steenhoven, Anton A

    2010-01-01

    Many researchers have already attempted to model vasoconstriction responses, commonly using the mathematical representation proposed by Stolwijk (1971 NASA Contractor Report CR-1855 (Washington, DC: NASA)). Model makers based the parameter values in this formulation either on estimations or by attributing the difference between their passive models and measurement data fully to thermoregulation. These methods are very sensitive to errors. This study aims to present a reliable method for determining physiological values in the vasoconstriction formulation. An experimental protocol was developed that enabled us to derive the local proportional amplification coefficients of the toe, leg and arm and the transient vasoconstrictor tone. Ten subjects participated in a cooling experiment. During the experiment, core temperature, skin temperature, skin perfusion, forearm blood flow and heart rate variability were measured. The contributions to the normalized amplification coefficient for vasoconstriction of the toe, leg and arm were 84%, 11% and 5%, respectively. Comparison with relative values in the literature showed that the estimated values of Stolwijk and the values mentioned by Tanabe et al (2002 Energy Build. 34 637-46) were comparable with our measured values, but the values of Gordon (1974 The response of a human temperature regulatory system model in the cold PhD Thesis University of California, Santa Barbara) and Fiala et al (2001 Int. J. Biometeorol. 45 143159) differed significantly. With the help of regression analysis a relation was formulated between the error signal of the standardized core temperature and the vasoconstrictor tone. This relation was formulated in a general applicable way, which means that it can be used for situations where vasoconstriction thresholds are shifted, like under anesthesia or during motion sickness. PMID:19940347

  13. Modulation of the LKB1-AMPK Signalling Pathway Underpins Hypoxic Pulmonary Vasoconstriction and Pulmonary Hypertension.

    PubMed

    Evans, A Mark; Lewis, Sophronia A; Ogunbayo, Oluseye A; Moral-Sanz, Javier

    2015-01-01

    Perhaps the defining characteristic of pulmonary arteries is the process of hypoxic pulmonary vasoconstriction (HPV) which, under physiological conditions, supports ventilation-perfusion matching in the lung by diverting blood flow away from oxygen deprived areas of the lung to oxygen rich regions. However, when alveolar hypoxia is more widespread, either at altitude or with disease (e.g., cystic fibrosis), HPV may lead to hypoxic pulmonary hypertension. HPV is driven by the intrinsic response to hypoxia of pulmonary arterial smooth muscle and endothelial cells, which are acutely sensitive to relatively small changes in pO2 and have evolved to monitor oxygen supply and thus address ventilation-perfusion mismatch. There is now a consensus that the inhibition by hypoxia of mitochondrial oxidative phosphorylation represents a key step towards the induction of HPV, but the precise nature of the signalling pathway(s) engaged thereafter remains open to debate. We will consider the role of the AMP-activated protein kinase (AMPK) and liver kinase B1 (LKB1), an upstream kinase through which AMPK is intimately coupled to changes in oxygen supply via mitochondrial metabolism. A growing body of evidence, from our laboratory and others, suggests that modulation of the LKB1-AMPK signalling pathway underpins both hypoxic pulmonary vasoconstriction and the development of pulmonary hypertension. PMID:26303471

  14. Endothelium attenuates ethanol induced vasoconstriction of arteries

    SciTech Connect

    Morley, D.; Bove, A.A.; Walter, J. )

    1990-02-26

    The authors have previously demonstrated that clinically relevant doses of ethanol (ETH) caused significant vasoconstriction of rabbit thoracic aorta. This study examined the role of endothelium in ethanol vasoconstriction. Thoracic aorta was harvested from 3 New Zealand White rabbits after anesthetization with sodium pentobarbital. Twelve aortic 3 mm rings were mounted in organ baths attached to force transducers and recording apparatus. Six of the twelve rings were denuded. Denudation was confirmed by challenge with acetylcholine (10-4 M). Resting tension was set at 10 grams and the rings equilibrated in 37 C Krebs-Heinsleit solution for 2 hours. Then, the response to norepinephrine (NE) was established (10-8 to 10-5 M). After reattaining resting tension, the response to ETH (500-2,500 ug/ml) was recorded. ETH produced significant vasoconstriction in both non-denuded (48{plus minus}7% of NE max) and denuded (58{plus minus}2% of NE max) arteries. Vasoconstriction was significantly higher in the denuded condition. The authors conclude that the predominant ETH action on arteries is based in vascular smooth muscle although endothelium acts to attenuate the ETH induced vasoconstrictor response.

  15. Thyroidectomy Under Regional Anaesthesia: An ORL Perspective

    PubMed Central

    K. B, Prashanth; Mohammed, Shamna J.; Pereira, Nivedeeta J.; Gupta, Srijoy; K. R, Sumanth; K. M, Triveni

    2015-01-01

    Background The use of regional anaesthesia as an effective alternative to general anaesthesia in thyroid surgeries is now being accepted in many parts of the world. In this day of computers and technology, there is an increased awareness among the people of the available options of anaesthesia and the adverse effects of general anaesthesia. They thus have an inclination to avoid general anaesthesia wherever feasible. This study dwells on the use of regional anaesthesia as an alternative tool that can be offered to the patients undergoing thyroidectomy. Aims This study aims at analysing the effectiveness, safety, ease and patient acceptability of performing thyroidectomies under regional anaesthesia. Settings and Design This prospective study was performed at a university – affiliated hospital. Materials and Methods Twenty nine patients who underwent thyroidectomy for benign thyroid diseases under regional anaesthesia were included in this study: 20 patients under deep cervical plexus block and 9 patients under cervical epidural anaesthesia. Statistical analysis used Z-test and validity test. Results In our study, all the 29 patients who underwent thyroidectomy under regional anaesthesia found the anaesthesia effective and were comfortable throughout the procedure. The surgeon too was at ease while performing the surgery. No complications were recorded. Conclusion In our present study, regional anaesthesia (Cervical epidural anaesthesia and Cervical plexus block) has been used safely and effectively in 29 thyroid surgeries. We conclude that although regional anaesthesia has been reserved for high risk thyroidectomies it may be offered as effective alternative to general anaesthesia even in routine thyroid surgeries. PMID:26557548

  16. H2S induces vasoconstriction of rat cerebral arteries via cAMP/adenylyl cyclase pathway.

    PubMed

    Li, Sen; Ping, Na-Na; Cao, Lei; Mi, Yan-Ni; Cao, Yong-Xiao

    2015-12-15

    Hydrogen sulfide (H2S), traditionally known for its toxic effects, is now involved in regulating vascular tone. Here we investigated the vasoconstrictive effect of H2S on cerebral artery and the underlying mechanism. Sodium hydrosulfide (NaHS), a donor of H2S, concentration-dependently induced vasoconstriction on basilar artery, which was enhanced in the presence of isoprenaline, a β-adrenoceptor agonist or forskolin, an adenylyl cyclase activator. Administration of NaHS attenuated the vasorelaxant effects of isoprenaline or forskolin. Meanwhile, the NaHS-induced vasoconstriction was diminished in the presence of 8B-cAMP, an analog of cAMP, but was not affected by Bay K-8644, a selective L-type Ca(2+) channel agonist. These results could be explained by the revised effects of NaHS on isoprenaline-induced cAMP elevation and forskolin-stimulated adenylyl cyclase activity. Additionally, NaHS-induced vasoconstriction was enhanced by removing the endothelium or in the presence of L-NAME, an inhibitor of nitric oxide synthase. L-NAME only partially attenuated the effect of NaHS which was given together with forskolin on the pre-contracted artery. In conclusion, H2S induces vasoconstriction of cerebral artery via, at least in part, cAMP/adenylyl cyclase pathway. PMID:26524654

  17. Reversible cerebral vasoconstriction syndrome: a comprehensive update.

    PubMed

    Mehdi, Ali; Hajj-Ali, Rula A

    2014-09-01

    Reversible cerebral vasoconstriction syndrome (RCVS) is a clinico-radiological syndrome characterized by recurrent thunderclap headache, with or without neurologic symptoms, and reversible vasoconstriction of cerebral arteries. RCVS affects patients in various racial and ethnic groups and in all age groups, although most commonly in the fourth decade of life. Many conditions and exposures have been linked to RCVS, including vasoactive drugs and the peripartum period. Disturbance of the cerebral vascular tone is thought to contribute to the disease's pathophysiology. RCVS generally follows a monophasic course. Associated strokes and cerebral hemorrhages are not uncommon. In this review we will attempt to provide a comprehensive overview of RCVS, with emphasis on the controversies in the field and the newest findings in the reported literature. PMID:25138149

  18. Systems Biology of HBOC-Induced Vasoconstriction

    PubMed Central

    Hai, Chi-Ming

    2011-01-01

    Vasoconstriction is a major adverse effect of HBOCs. The use of a single drug for attenuating HBOC-induced vasoconstriction has been tried with limited success. Since HBOC causes disruptions at multiple levels of organization in the vascular system, a systems approach is helpful to explore avenues to counteract the effects of HBOC at multiple levels by targeting multiple sites in the system. A multi-target approach is especially appropriate for HBOC-induced vasoconstriction, because HBOC disrupts the cascade of amplification by NO-cGMP signaling and protein phosphorylation, ultimately resulting in vasoconstriction. Targeting multiple steps in the cascade may alter the overall gain of amplification, thereby limiting the propagation of disruptive effects through the cascade. As a result, targeting multiple sites may accomplish a relatively high overall efficacy at submaximal drug doses. Identifying targets and doses for developing a multi-target combination HBOC regimen for oxygen therapeutics requires a detailed understanding of the systems biology and phenotypic heterogeneity of the vascular system at multiple layers of organization, which can be accomplished by successive iterations between experimental studies and mathematical modeling at multiple levels of vascular systems and organ systems. Towards this goal, this article addresses the following topics: a) NO-scavenging by HBOC, b) HBOC autoxidation-induced reactive oxygen species generation and endothelial barrier dysfunction, c) NO- cGMP signaling in vascular smooth muscle cells, d) NO and cGMP-dependent regulation of contractile filaments in vascular smooth muscle cells, e) phenotypic heterogeneity of vascular systems, f) systems biology as an approach to developing a multi-target HBOC regimen. PMID:21726185

  19. Triptans and chest symptoms: the role of pulmonary vasoconstriction.

    PubMed

    Dodick, D W

    2004-04-01

    Triptans are effective and well tolerated in the treatment of acute migraine. Chest symptoms are a common adverse effect unrelated to coronary vasoconstriction in most patients. Although the aetiology of chest symptoms remains to be fully defined, pulmonary vasoconstriction is a possible underlying mechanism. Pre-clinical studies of isolated human blood vessels were used to identify the cerebral selectivity of triptans and ascertain if selectivity vs the pulmonary vasculature predicts a lower rate of chest symptoms. Controlled clinical trials and post-marketing surveillance studies were reviewed to document the incidence of chest symptoms after triptan therapy. In clinical trials, the incidence of chest symptoms at usual therapeutic doses ranged from 1 to 4% depending on the triptan and study design, whereas in post-marketing surveillance studies, up to 41% of patients specifically asked about chest symptoms reported them. A comparative clinical trial showed that almotriptan was associated with lower incidence of chest symptoms than sumatriptan (0.3 vs 2.2%). The intrinsic activity of almotriptan, a second-generation triptan, on human pulmonary arteries and veins was lower than that of sumatriptan. Pre-clinical studies of isolated pulmonary blood vessels may predict the clinical likelihood of chest symptoms; however, additional comparisons are needed. PMID:15030540

  20. Progesterone suppressed vasoconstriction in human umbilical vein via reducing calcium entry.

    PubMed

    He, Yun; Gao, Qinqin; Han, Bing; Zhu, Xiaolin; Zhu, Di; Tao, Jianying; Chen, Jie; Xu, Zhice

    2016-04-01

    The aim of this study was to evaluate the actions of progesterone on human umbilical vein (HUV) from normal pregnancies and the possible underlying mechanisms involved. HUV rings were suspended in organ baths and exposed to progesterone followed by phenylephrine (PE) or serotonin (5-HT). Progesterone suppressed PE- or 5-HT-induced vasoconstriction in HUV rings. The inhibitory effect induced by progesterone was not influenced by nitric oxide syntheses inhibitor, prostaglandins syntheses blocker, the integrity of endothelium, selective progesterone receptor or potassium channel antagonists. Further testing showed that progesterone and nifedipine (a blocker for L-type calcium channels) produced similar inhibitory effects on PE-, 5-HT-, Bay-k8644-, KCl-induced vasoconstriction in Krebs solution as well as CaCl2-induced vasoconstriction in Ca(2+)-free Krebs solution. But the inhibitory effect of mibefradil (mibe, a blocker for L-type (CaV1.2) and T-type calcium channels (CaV3.2)) on PE-, 5-HT-induced vasoconstriction was significantly greater than progesterone or nifedipine in Krebs solution. Furthermore, progesterone did not affect the vasoconstriction caused by PE, 5-HT, or caffeine in Ca(2+)-free Krebs solution. In addition, incubation HUV with progesterone did not change CaV1.2 and progesterone receptor (PR) expressions. The results gained demonstrated that progesterone could suppress multiple agonist-induced vasoconstrictions in HUV, mainly due to a reduction of calcium entry through L-type calcium channels, not endothelium-dependent vascular relaxation pathways, potassium channels, or Ca(2+) release from intracellular stores, providing new information important to further understanding the contribution of progesterone in the regulation of the placental-fetal circulation. PMID:26875775

  1. Vasoconstriction induced by salivary gland extracts from ixodid ticks.

    PubMed

    Pekáriková, Danica; Rajská, Petra; Kazimírová, Mária; Pecháňová, Olga; Takáč, Peter; Nuttall, Patricia A

    2015-12-01

    In their quest for blood, most haematophagous parasites secrete vasodilators in their saliva to counter the host haemostatic response of vasoconstriction. Surprisingly, salivary gland extracts from adult female Dermacentor reticulatus and Rhipicephalus appendiculatus ticks induced constriction in a rat femoral artery model; males induced vasoconstriction or vasodilation depending on the time of feeding. Based on comparative HPLC fractionation, the active compounds inducing vasoconstriction do not appear to be prostaglandins (which ticks normally use as vasodilators). Vasoconstriction may be unique to ixodid ticks, helping them control blood flow during their prolonged blood-feeding of up to 10 days or more. PMID:26432295

  2. Hemolysate-mediated renal vasoconstriction and hypersensitization.

    PubMed

    Burke, T J; Falk, S; Conger, J D; Voelkel, N F

    1999-01-01

    The present studies measured vessel diameter, before and after addition of hemolysate, in isolated afferent arterioles (AA) and efferent arterioles (EA) obtained from the rat kidney. Human red blood cells (RBC) were hemolyzed in distilled water and membranes were discarded after centrifugation. Hemolysate added to the bath solution caused vigorous AA and EA contraction and, after washout, hypersensitized the AA and EA to doses of angiotensin II (AII) which would normally only elicit 50% contraction (EC50). Neither the contraction nor the hypersensitization were mimicked by pure human hemoglobin. The vasoconstrictive responses in the AA and EA were accompanied by increased cytosolic-free calcium concentration. Further purification (desalting) of the hemolysate to remove substance of < or = 1000 Da (which include ATP) did not eliminate the vasoconstrictive component from the hemolysate. Finally, cultured rat aortic vascular smooth muscle cells also demonstrated a rapid increase in (Ca2+i) when exposed to hemolysate. This increase in (Ca2+i) was, in part, dependent on Ca2+ influx since it could be attenuated with diltiazem (10(-5) M). In conclusion, hemolysate contains a factor which induces contractions of the isolated rat kidney AA and EA and rapid elevations in (Ca2+i). This factor, from hemolyzed RBC, is not hemoglobin itself. PMID:10048115

  3. Endothelin-mediated vasoconstriction in postischemic newborn intestine.

    PubMed

    Nankervis, C A; Schauer, G M; Miller, C E

    2000-10-01

    We previously suggested that the profound, sustained vasoconstriction noted in 3-day-old swine intestine after a moderate episode of ischemia-reperfusion (I/R) reflects the unmasking of underlying constrictor tone consequent to a loss of endothelium-derived nitric oxide (NO). In this study, we sought to determine whether endothelin-1 (ET-1) was the unmasked constrictor and whether selective loss of endothelial ET(B) receptors, which mediate NO-based vasodilation, participated in the hemodynamic consequences of I/R in newborn intestine. Studies were performed in innervated, autoperfused intestinal loops in 3- and 35-day-old swine. Selective blockade of ET(A) receptors with BQ-610 had no effect on hemodynamics under control conditions; however, when administered before and during I/R, BQ-610 significantly attenuated the post-I/R vasoconstriction and reduction in arteriovenous O(2) difference in the younger group. In 3-day-old intestine, reduction of intestinal O(2) uptake to a level similar to that noted after I/R by lowering tissue temperature had no effect on the response to BQ-610 or ET-1, indicating that the change in response to BQ-610 noted after I/R was not simply consequent to the reduction in tissue O(2) demand. In studies in mesenteric artery rings suspended in myographs, we observed a leftward shift in the dose-response curve for ET-1 after selective blockade of ET(B) receptors with BQ-788 in 3- but not 35-day-old swine. Rings exposed to I/R in vivo behaved in a manner similar to control rings treated with BQ-788 or endothelium-denuded non-I/R rings. PMID:11005754

  4. The cold effects on circulatory inflammation, thrombosis and vasoconstriction in type 2 diabetic patients.

    PubMed

    Cai, Jing; Meng, Xia; Wang, Cuicui; Chen, Renjie; Zhou, Ji; Xu, Xiaohui; Ha, Sandie; Zhao, Zhuohui; Kan, Haidong

    2016-10-15

    Short-term associations between temperature variation and adverse cardiovascular outcomes have been well documented. However, it remains unclear whether these temperature-related cardiovascular effects are reflected in circulating biomarkers. We aimed to examine the associations between ambient temperature and circulating biomarkers of inflammation, coagulation and vasoconstriction. We collected 207 blood samples from a panel of 35 type 2 diabetes mellitus patients. Sixteen biomarkers of inflammation, coagulation and vasoconstriction were repeatedly measured over six follow-ups. The short-term associations between air temperature and these biomarkers were assessed by mixed-effect models with controls of demographic characteristics and main air pollutants. We found significant and acute effects of temperature on circulatory biomarkers occurred as early as 3h after exposure, peaked at 25-48h and lasted until 72h after exposure. For example, a 1°C decrease in the 25-48h average of air temperature was associated with 2.2%-15.1% increases in biomarkers of inflammation, 1.4%-24.5% of coagulation and 8.2% of vasoconstriction. Our results provided significant evidence that a temperature decline results in a response in biomarkers of inflammation, coagulation and vasoconstriction biomarkers, suggesting them to be the potential biologic mechanisms underlying the cardiovascular effects of temperature variation, and may have implications for disease prevention. PMID:27295598

  5. Vibration causes acute vascular injury in a two-step process: vasoconstriction and vacuole disruption.

    PubMed

    Govindaraju, Sandya R; Bain, James Lw; Eddinger, Thomas J; Riley, Danny A

    2008-08-01

    Hand-arm vibration syndrome is a vasospastic and neurodegenerative occupational disease. In the current study, the mechanism of vibration-induced vascular smooth muscle cell (SMC) injury was examined in a rat-tail vibration model. Tails of male Sprague Dawley rats were vibrated continuously for 4 hr at 60 Hz, 49 m/s(2) with or without general anesthesia. Ventral tail arteries were aldehyde fixed and embedded in epoxy resin to enable morphological analysis. Vibration without anesthesia caused vasoconstriction and vacuoles in the SMC. Anesthetizing rats during vibration prevented vasoconstriction and vacuole formation. Exposing tail arteries in situ to 1 mM norepinephrine (NE) for 15 min induced the greatest vasoconstriction and vacuolation. NE induced vacuoles were twice as large as those formed during vibration. When vibrated 4 hr under anesthesia after pretreatment with NE for 15 min, the SMC lacked vacuoles and exhibited a longitudinal banding pattern of dark and light staining. The extracellular matrix was filled with particulates, which were confirmed by electron microscopy to be cellular debris. The present findings demonstrate that vibration-induced vasoconstriction (SMC contraction) requires functioning central nervous system reflexes, and the physical stress of vibration damages the contracted SMC by dislodging and fragmenting SMC vacuoles. PMID:18493932

  6. Hydrogen sulfide mediates hypoxic vasoconstriction through a production of mitochondrial ROS in trout gills.

    PubMed

    Skovgaard, Nini; Olson, Kenneth R

    2012-09-01

    Hypoxic pulmonary vasoconstriction (HPV) is an adaptive response that diverts pulmonary blood flow from poorly ventilated and hypoxic areas of the lung to more well-ventilated parts. This response is important for the local matching of blood perfusion to ventilation and improves pulmonary gas exchange efficiency. HPV is an ancient and highly conserved response, expressed in the respiratory organs of all vertebrates, including lungs of mammals, birds, and reptiles; amphibian skin; and fish gills. The mechanism underlying HPV and how cells sense low Po(2) remains elusive. In perfused trout gills (Oncorhynchus mykiss), acute hypoxia, as well as H(2)S, caused an initial and transient constriction of the vasculature. Inhibition of the enzymes cystathionine-β-synthase and cystathionine-γ-lyase, which blocks H(2)S production, abolished the hypoxic response. Individually blocking the four complexes in the electron transport chain abolished both the hypoxic and the H(2)S-mediated constriction. Glutathione, an antioxidant and scavenger of superoxide, attenuated the vasoconstriction in response to hypoxia and H(2)S. Furthermore, diethyldithiocarbamate, an inhibitor of superoxide dismutase, attenuated the hypoxic and H(2)S constriction. This strongly suggests that H(2)S mediates the hypoxic vasoconstriction in trout gills. H(2)S may stimulate the mitochondrial production of superoxide, which is then converted to hydrogen peroxide (H(2)O(2)). Thus, H(2)O(2) may act as the "downstream" signaling molecule in hypoxic vasoconstriction. PMID:22739350

  7. Inhibition of α-adrenergic vasoconstriction in exercising human thigh muscles

    PubMed Central

    Wray, D Walter; Fadel, Paul J; Smith, Michael L; Raven, Peter; Sander, Mikael

    2004-01-01

    The mechanisms underlying metabolic inhibition of sympathetic responses within exercising skeletal muscle remain incompletely understood. The aim of the present study was to test whether α2-adrenoreceptor-mediated vasoconstriction was more sensitive to metabolic inhibition than α1-vasoconstriction during dynamic knee-extensor exercise. We studied healthy volunteers using two protocols: (1) wide dose ranges of the α-adrenoreceptor agonists phenylephrine (PE, α1 selective) and BHT-933 (BHT, α2 selective) were administered intra-arterially at rest and during 27 W knee-extensor exercise (n = 13); (2) flow-adjusted doses of PE (0.3 μg kg−1 l−1) and BHT (15 μg kg−1 l−1) were administered at rest and during ramped exercise (7 W to 37 W; n= 10). Ultrasound Doppler and thermodilution techniques provided direct measurements of femoral blood flow (FBF). PE (0.8 μg kg−1) and BHT (40 μg kg−1) produced comparable maximal reductions in FBF at rest (−58 ± 6 versus−64 ± 4%). Despite increasing the doses, PE (1.6 μg kg−1 min−1) and BHT (80 μg kg−1 min−1) caused significantly smaller changes in FBF during 27 W exercise (−13 ± 4 versus−3 ± 5%). During ramped exercise, significant vasoconstriction at lower intensities (7 and 17 W) was seen following PE (−16 ± 5 and −16 ± 4%), but not BHT (−2 ± 4 and −4 ± 5%). At the highest intensity (37 W), FBF was not significantly changed by either drug. Collectively, these data demonstrate metabolic inhibition of α-adrenergic vasoconstriction in large postural muscles of healthy humans. Both α1- and α2-adrenoreceptor agonists produce comparable vasoconstriction in the resting leg, and dynamic thigh exercise attenuates α1- and α2-mediated vasoconstriction similarly. However, α2-mediated vasoconstriction appears more sensitive to metabolic inhibition, because α2 is completely inhibited even at low workloads, whereas α1 becomes progressively inhibited with increasing workloads. PMID

  8. Caveolae regulate vasoconstriction of conduit arteries to angiotensin II in hindlimb unweighted rats.

    PubMed

    Wang, Zhongchao; Bai, Yungang; Yu, Jinwen; Liu, Huan; Cheng, Yaoping; Liu, Yonghong; Xie, Xiaoping; Ma, Jin; Bao, Junxiang

    2015-10-15

    Weightlessness induces the functional remodelling of arteries, but the changes to angiotensin II (Ang II)-elicited vasoconstriction and the underlying mechanism have never been reported. Caveolae are invaginations of the cell membrane crucial for the contraction of vascular smooth muscle cells, so we investigated the adaptation of Ang II-elicited vasoconstriction to simulated weightlessness and the role of caveolae in it. The 4 week hindlimb unweighted (HU) rat was used to simulate the effects of weightlessness. Ang II-elicited vasoconstriction was measured by isometric force recording. The morphology of caveolae was examined by transmission electron microscope. The binding of the angiotensin II type 1 receptor (AT1 ) and caveolin-1 (cav-1) was examined by coimmunoprecipitation and Western blot. We found that the maximal developing force (E(max)) of Ang II-elicited vasoconstriction was decreased in abdominal aorta by 30.6%, unchanged in thoracic aorta and increased in carotid artery by 17.9% after HU, while EC50 of the response was increased in all three arteries (P < 0.05). AT1 desensitization upon activation was significantly reduced by HU in all three arteries, as was the number of caveolae (P < 0.05). Furthermore, Ang II promoted the binding of AT1 and cav-1 significantly in control but not HU arteries. Both the number of caveolae and the binding of AT1 and cav-1 in HU arteries were restored by cholesterol pretreatment which also reinstated the change in EC50 as well as the level of AT1 desensitization. These results indicate that modified caveolae in vascular smooth muscle cells could interfere with the binding of AT1 and cav-1 mediating the adaptation of Ang II-elicited vasoconstriction to HU. PMID:26260249

  9. Portuguese wine regions under a changing climate

    NASA Astrophysics Data System (ADS)

    Santos, João A.; Fraga, Helder; Malheiro, Aureliano C.; Moutinho-Pereira, José; Jones, Gregory V.; Pinto, Joaquim G.

    2014-05-01

    Viticulture and wine production are among the most important sectors of the Portuguese economy. However, as grapevines are strongly affected by weather and climate, climate change may represent an important threat to wine production. The current (1950-2000) and future (2041-2070) bioclimatic conditions in Portugal are discussed by analyzing a number of indices suitable for viticultural zoning, including a categorized bioclimatic index. A two-step method of spatial pattern downscaling is applied in order to achieve a very high spatial resolution (of approximately 1 km) throughout Portugal. Future projections are based on an ensemble of 13 climate model transient experiments, forced by the SRES A1B emission scenario. Results for the recent past are in clear agreement with the current distribution of vineyards and of the established Denomination of Origin regions. Furthermore, the typical climatic conditions associated with each grapevine variety that are currently grown in Portugal are assessed. Under future scenarios, nevertheless, the current conditions are projected to change significantly towards a lower bioclimatic diversity. This can be explained by the projected warming and drying in future decades. The resulting changes in varietal suitability and wine characteristics of each region may thereby bring important challenges for the Portuguese winemaking sector. As such, new measures need to be timely implemented to adapt to these climate change projections and to mitigate their likely detrimental impacts on the Portuguese economy. Acknowledgments: this work is supported by European Union Funds (FEDER/COMPETE - Operational Competitiveness Programme) and by national funds (FCT - Portuguese Foundation for Science and Technology) under the project ClimVineSafe (PTDC/AGR-ALI/110877/2009).

  10. Effects of posture on blood flow diversion by hypoxic pulmonary vasoconstriction in dogs

    NASA Technical Reports Server (NTRS)

    Walther, S. M.; Domino, K. B.; Hlastala, M. P.

    1998-01-01

    We used differential excretion of sulphur hexafluoride from the left and right lung to measure blood flow diversion by hypoxic pulmonary vasoconstriction (HPV) in the prone and supine positions in dogs (n = 9). Gas exchange was assessed using the multiple inert gas elimination technique. Blood flow diversion from the hypoxic (3% oxygen) left lung was mean 70.7 (SD 11.2)% in the supine compared with 57.0 (12.1)% in the prone position (P < 0.02). The supine position was associated with increased perfusion to low VA/Q regions (P < 0.05). The increased flow diversion with hypoxia in the supine position was associated with more ventilation to high VA/Q regions (P < 0.05). We conclude that flow diversion by hypoxic pulmonary vasoconstriction is greater in the supine position. This effect could contribute to the variable response in gas exchange with positioning in patients with ARDS.

  11. Cold-induced vasoconstriction may persist long after cooling ends: an evaluation of multiple cryotherapy units

    PubMed Central

    Khoshnevis, Sepideh; Craik, Natalie K.

    2015-01-01

    Purpose Localized cooling is widely used in treating soft tissue injuries by modulating swelling, pain, and inflammation. One of the primary outcomes of localized cooling is vasoconstriction within the underlying skin. It is thought that in some instances, cryotherapy may be causative of tissue necrosis and neuropathy via cold-induced ischaemia leading to nonfreezing cold injury (NFCI). The purpose of this study is to quantify the magnitude and persistence of vasoconstriction associated with cryotherapy. Methods Data are presented from testing with four different FDA approved cryotherapy devices. Blood perfusion and skin temperature were measured at multiple anatomical sites during baseline, active cooling, and passive rewarming periods. Results Local cutaneous blood perfusion was depressed in response to cooling the skin surface with all devices, including the DonJoy (DJO, p = 2.6 × 10−8), Polar Care 300 (PC300, p = 1.1 × 10−3), Polar Care 500 Lite (PC500L, p = 0.010), and DeRoyal T505 (DR505, p = 0.016). During the rewarming period, parasitic heat gain from the underlying tissues and the environment resulted in increased temperatures of the skin and pad for all devices, but blood perfusion did not change significantly, DJO (n.s.), PC300 (n.s.), PC500L (n.s.), and DR505 (n.s.). Conclusions The results demonstrate that cryotherapy can create a deep state of vasoconstriction in the local area of treatment. In the absence of independent stimulation, the condition of reduced blood flow persists long after cooling is stopped and local temperatures have rewarmed towards the normal range, indicating that the maintenance of vasoconstriction is not directly dependent on the continuing existence of a cold state. The depressed blood flow may dispose tissue to NFCI. PMID:24562697

  12. Transmyocardial Revascularization Ameliorates Ischemia by Attenuating Paradoxical Catecholamine-Induced Vasoconstriction

    PubMed Central

    Le, D. Elizabeth; Powers, Eric R.; Bin, Jian-Ping; Leong-Poi, Howard; Goodman, N. Craig; Kaul, Sanjiv

    2007-01-01

    The mechanism by which transmyocardial revascularization (TMR) offers clinical benefit is controversial. We hypothesized that TMR ameliorates ischemia by reversing paradoxical catecholamine-induced vasoconstriction. Chronic ischemic cardiomyopathy was created in 11 dogs by placing ameroid constrictors on the proximal coronary arteries and their major branches. Six weeks later, 35 channels were created percutaneously in the left circumflex artery (LCx) region with the left anterior descending artery (LAD) region serving as control. At rest, wall thickening (WT) and myocardial blood flow (MBF) did not change in the treated region, while they deteriorated in the control bed. Contractile and MBF reserve increased in the treated region but deteriorated in the control region. There was diminished 123I-metaiodobenzylguanidine uptake and significant reduction in noradrenergic nerves in the treated region compared to control region, with corresponding reduction in tissue tyrosine hydroxylase activity. We conclude that the absence of catecholamine-induced reduction in MBF reserve and contractile reserve in the TMR treated region with associated evidence of neuronal injury indicates that the relief of exercise-induced ischemia after TMR is most likely due to reversal of paradoxical catecholamine-induced vasoconstriction. These findings may have implications in selecting patients who would benefit from TMR. PMID:17386383

  13. Hypoxic pulmonary vasoconstriction, carotid body function and erythropoietin production in adult rats perinatally exposed to hyperoxia

    PubMed Central

    Prieto-Lloret, Jesus; Ramirez, Maria; Olea, Elena; Moral-Sanz, Javier; Cogolludo, Angel; Castañeda, Javier; Yubero, Sara; Agapito, Teresa; Gomez-Niño, Angela; Rocher, Asuncion; Rigual, Ricardo; Obeso, Ana; Perez-Vizcaino, Francisco; González, Constancio

    2015-01-01

    Adult mammalians possess three cell systems that are activated by acute bodily hypoxia: pulmonary artery smooth muscle cells (PASMC), carotid body chemoreceptor cells (CBCC) and erythropoietin (EPO)-producing cells. In rats, chronic perinatal hyperoxia causes permanent carotid body (CB) atrophy and functional alterations of surviving CBCC. There are no studies on PASMC or EPO-producing cells. Our aim is to define possible long-lasting functional changes in PASMC or EPO-producing cells (measured as EPO plasma levels) and, further, to analyse CBCC functional alterations. We used 3- to 4-month-old rats born and reared in a normal atmosphere or exposed to perinatal hyperoxia (55–60% O2 for the last 5–6 days of pregnancy and 4 weeks after birth). Perinatal hyperoxia causes an almost complete loss of hypoxic pulmonary vasoconstriction (HPV), which was correlated with lung oxidative status in early postnatal life and prevented by antioxidant supplementation in the diet. O2-sensitivity of K+ currents in the PASMC of hyperoxic animals is normal, indicating that their inhibition is not sufficient to trigger HPV. Perinatal hyperoxia also abrogated responses elicited by hypoxia on catecholamine and cAMP metabolism in the CB. An increase in EPO plasma levels elicited by hypoxia was identical in hyperoxic and control animals, implying a normal functioning of EPO-producing cells. The loss of HPV observed in adult rats and caused by perinatal hyperoxia, comparable to oxygen therapy in premature infants, might represent a previously unrecognized complication of such a medical intervention capable of aggravating medical conditions such as regional pneumonias, atelectases or general anaesthesia in adult life. Key points Adult animals that have been perinatally exposed to oxygen-rich atmospheres (hyperoxia), recalling those used for oxygen therapy in infants, exhibit a loss of hypoxic pulmonary vasoconstriction, whereas vasoconstriction elicited by depolarizing agents is

  14. Effects of endothelin receptor antagonist on cyclosporine-induced vasoconstriction in isolated rat renal arterioles.

    PubMed Central

    Lanese, D M; Conger, J D

    1993-01-01

    Recent evidence suggests that the potent constrictor peptide, endothelin (ET) has a mediating role in cyclosporine A (CsA)-related renal vasoconstriction. However, the nature of the CsA-ET interaction and effect on the renal vasculature is uncertain. The purpose of the present study was twofold: (a) to determine if CsA exposure caused direct local release of ET from the endothelium of the renal microvasculature and (b) to determine if locally generated ET has paracrine effects on the underlying vascular smooth muscle to induce vasoconstriction. Experiments were performed in isolated rat renal arterioles. First it was determined that both afferent arteriole (AA) and efferent arteriole (EA) exhibited concentration-dependent decreases in lumen diameter to increasing molar concentrations of CsA. The AA was more sensitive to the vasoconstrictive effects of CsA than the EA. Next, the blocking effect of a recently synthesized putative ETA receptor antagonist was verified in both the AA and EA, where it was found that the cyclic peptide cyclo D-Asp-L-Pro-D-Val-L-Leu-D-Trp totally inhibited the vasoconstriction observed with ET addition. Finally, the role of locally stimulated ET in CsA-induced vasoconstriction was tested by determining the effect of the ETA receptor antagonist on CsA-induced AA and EA constriction. In the AA the vasoconstrictor effect of 10(-11) M CsA was completely blocked by the ETA receptor antagonist. However, in contrast to AA, 10(-11) M CsA in EA in the presence of the ETA receptor antagonist decreased EA lumen diameter by a mean of 41% from baseline (4.80 +/- 0.75 microns vs 7.80 +/- 0.84 microns, P < 0.05). This change in lumen diameter was similar to that induced by CsA alone. These data suggest that CsA directly constricts renal microvessels. This effect is mediated by ET in the AA but not the EA. PMID:8486781

  15. Effects of mitochondrial inhibitors and uncouplers on hypoxic vasoconstriction in rabbit lungs.

    PubMed

    Weissmann, Norbert; Ebert, Nadine; Ahrens, Marit; Ghofrani, Hossein A; Schermuly, Ralph T; Hänze, Jörg; Fink, Ludger; Rose, Frank; Conzen, Jörg; Seeger, Werner; Grimminger, Friedrich

    2003-12-01

    Hypoxic pulmonary vasoconstriction (HPV) matches lung perfusion to ventilation for optimizing pulmonary gas exchange; however, the underlying mechanism has not yet been fully elucidated. Lung nitric oxide (NO) generation appears to be involved in this process. Recently, mitochondria have been proposed as oxygen sensors, with HPV signaling via a hypoxia-induced increase in the generation of reactive oxygen species derived from mitochondrial complex III and escaping through an anion channel into the cytoplasm. In addition, complex II has been suggested to be specifically involved in hypoxia-dependent generation of reactive oxygen species in the lung. We investigated the effects of several mitochondrial inhibitors and uncouplers on the strength of HPV, and asked for their capacity to mimic HPV during normoxia in isolated buffer-perfused rabbit lungs. Specificity of the agents for HPV was tested by comparison of their effects on non-hypoxia-induced vasoconstriction, elicited by the thromboxane mimetic U46619. Interference with NO metabolism was determined by performing parallel studies with blocked lung NO generation and by measurement of exhaled NO. Rotenone, 3-nitroproprionic acid, and myxothiazol dose-dependently inhibited HPV without being mimics of HPV during normoxia. The inhibitory effect of these agents was only partly specific for HPV by comparison with U46619-induced vasoconstriction. During pre-blocked lung NO synthesis, the selectivity for HPV inhibition was increased for rotenone, but largely lost for myxothiazol. 2-tenoyltrifluoroacetone resulted in an unspecific inhibition of HPV as compared with U46619-induced vasoconstriction. 1-methyl-4-phenylpyridinium iodide and 2-heptyl-4-hydroxyquinoline-N-oxide specifically suppressed HPV and increased normoxic vascular tone. Antimycin A suppressed HPV, an effect being specific in lungs with intact NO synthesis and only partly specific while blocking NO. However, this agent did not mimic HPV during normoxia, as

  16. MODULATION OF HYPOXIC PULMONARY VASOCONSTRICTION BY ERYTHROCYTIC NITRIC OXIDE

    EPA Science Inventory

    Abstract
    American Heart Association 2001

    Modulation of Hypoxic Pulmonary Vasoconstriction by Erythrocytic NO
    McMahon TJ1, Gow AJ1, Huang YCT4, Stamler JS1,2,3
    Departments of Medicine1 and Biochemistry2, and Howard Hughes Medical Institute3,
    Duke University Med...

  17. Phosphodiesterase-5 inhibitors oppose hyperoxic vasoconstriction and accelerate seizure development in rats exposed to hyperbaric oxygen.

    PubMed

    Demchenko, Ivan T; Ruehle, Alex; Allen, Barry W; Vann, Richard D; Piantadosi, Claude A

    2009-04-01

    Oxygen is a potent cerebral vasoconstrictor, but excessive exposure to hyperbaric oxygen (HBO(2)) can reverse this vasoconstriction by stimulating brain nitric oxide (NO) production, which increases cerebral blood flow (CBF)-a predictor of O(2) convulsions. We tested the hypothesis that phosphodiesterase (PDE)-5 blockers, specifically sildenafil and tadalafil, increase CBF in HBO(2) and accelerate seizure development. To estimate changes in cerebrovascular responses to hyperoxia, CBF was measured by hydrogen clearance in anesthetized rats, either control animals or those pretreated with one of these blockers, with the NO inhibitor N(omega)-nitro-l-arginine methyl ester (l-NAME), with the NO donor S-nitroso-N-acetylpenicillamine (SNAP), or with a blocker combined with l-NAME. Animals were exposed to 30% O(2) at 1 atm absolute (ATA) ("air") or to 100% O(2) at 4 or 6 ATA. EEG spikes indicated central nervous system CNS O(2) toxicity. The effects of PDE-5 blockade varied as a positive function of ambient Po(2). In air, CBF did not increase significantly, except after pretreatment with SNAP. However, at 6 ATA O(2), mean values for CBF increased and values for seizure latency decreased, both significantly; pretreatment with l-NAME abolished these effects. Conscious rats treated with sildenafil before HBO(2) were also more susceptible to CNS O(2) toxicity, as demonstrated by significantly shortened convulsive latency. Decreases in regional CBF reflect net vasoconstriction in the brain regions studied, since mean arterial pressures remained constant or increased throughout. Thus PDE-5 blockers oppose the protective vasoconstriction that is the initial response to hyperbaric hyperoxia, decreasing the safety of HBO(2) by hastening onset of CNS O(2) toxicity. PMID:19179645

  18. Reversible Cerebral Vasoconstriction Syndrome Presenting With Visual Field Defects.

    PubMed

    Raven, Meisha L; Ringeisen, Alexander L; McAllister, Angela R; Knoch, Daniel W

    2016-06-01

    A 45-year-old woman with a history of depression and anxiety, treated with selective serotonin reuptake inhibitors (SSRIs), experienced acute, recurrent, and severe bifrontal headaches. Over time, she developed a left homonymous hemianopia and mental status changes. MRA revealed segmental vasoconstriction of cerebral arteries in multiple vascular distributions. She was treated with a calcium-channel blocker and magnesium, and there was resolution of her symptoms and cerebrovascular changes. Her clinical course and neuroimaging findings were consistent with reversible cerebral vasoconstriction syndrome. Although rare, this disorder frequently manifests with visual complaints. Although the prognosis is generally favorable, patients with this syndrome require prompt diagnosis and care directed to avoid complications including stroke, seizure, and subarachnoid hemorrhage. PMID:26807800

  19. Reversible cerebral vasoconstriction syndrome: rare or underrecognized in children?

    PubMed

    Probert, Rebecca; Saunders, Dawn E; Ganesan, Vijeya

    2013-04-01

    Reversible cerebral vasoconstriction syndrome (RCVS) is a clinicoradiological diagnosis comprising 'thunderclap' headaches and reversible segmental vasoconstriction of cerebral arteries, occasionally complicated by ischaemic or haemorrhagic stroke. We report a case of RCVS in a 13-year-old male with severe thunderclap headaches and no focal neurological signs. Brain imaging showed multiple posterior circulation infarcts; cerebral computed tomography, magnetic resonance imaging, and catheter angiography showed multifocal irregularity and narrowing, but in different arterial segments. Laboratory studies did not support a diagnosis of vasculitis. Symptoms resolved over 3 weeks; magnetic resonance angiography 3 months later was normal and remained so after 2 years. We highlight the typical clinical features of RCVS in this case and suggest that the diagnosis should be considered in children with thunderclap headaches or stroke syndromes where headache is a prominent feature, especially if cerebrovascular imaging studies appear to be evolving or discrepant. PMID:23066702

  20. Reversible cerebral vasoconstriction syndrome and nonaneurysmal subarachnoid hemorrhage

    PubMed Central

    Barboza, Miguel A; Maud, Alberto; Rodriguez, Gustavo J

    2014-01-01

    Background Reversible cerebral vasoconstriction syndrome was first described by Call, Fleming, and colleagues. Clinically this entity presents acutely, with severe waxing and waning headaches (“thunderclap”), and occasional fluctuating neurological signs. Case presentation We present four subsequent cases of patients with severe thunderclap headache and brain tomography with evidence of subarachnoid hemorrhage. The brain angiogram showed no aneurysm but intracranial vasculopathy consistent with multiple areas of stenosis and dilatation (angiographic beading) in different territories. Conclusion Neurologists should be aware of Call Fleming syndrome presenting with severe headache and associated convexity subarachnoid hemorrhage. After other diagnoses are excluded, patients can be reassured about favorable prognosis with symptomatic management. Abbreviations RCVS Reversible cerebral vasoconstriction syndrome CT Computed tomography SAH Subarachnoid hemorrhage MR Magnetic resonance CTA Computed tomography angiography MRA Magnetic resonance angiography PMID:25132905

  1. Inhibition of Cerebral Vasoconstriction by Dantrolene and Nimodipine

    PubMed Central

    Salomone, S; Soydan, G; Moskowitz, MA; Sims

    2009-01-01

    Introduction Cerebral vasoconstriction is associated with increased cytosolic Ca2+ concentration in vascular smooth muscle, presumably due to Ca2+ influx and Ca2+ release from intracellular stores. We tested the hypothesis that dantrolene (a blocker of Ca2+-induced Ca2+ release from the ryanodine receptor channel on the sarco-endoplasmic reticulum) would potentiate the action of nimodipine (a voltage-dependent L-type Ca2+ channel blocker, considered standard therapy for SAH) in inhibiting the vasoconstriction of isolated cerebral arteries. Method Sprague-Dawley rat basilar and femoral arteries were analyzed for ryanodine receptor expression by immunofluorescence and PCR. Vasoconstriction of basilar artery ex vivo was measured in a wire myograph while exposed to serotonin (5-HT) or endothelin-1 (ET-1) in the presence or absence of dantrolene (10–100μM) and/or nimodipine (30nM). Femoral artery was examined for comparison. Results Basilar and femoral arteries express only the ryanodine receptor 3 (RyR3) isoform. In both basilar and femoral arteries dantrolene significantly inhibited the constriction to 5-HT, whereas it poorly affected the constriction to ET-1. The inhibitory effect of dantrolene on 5-HT was substantially increased by nimodipine, inducing a 10-fold increase in the 50% effective concentration of 5-HT and a 46% reduction in maximum basilar constriction. In femoral artery, dantrolene modestly affected constriction to phenylephrine and there was no interaction with nimodipine. Conclusion Dantrolene has synergistic effects with nimodipine against 5-HT-induced vasoconstriction in isolated cerebral arteries. Dantrolene-nimodipine interaction will require testing in a pathophysiological model but might provide treatment for reducing SAH-related vasospasm or other 5-HT-related vasospastic syndromes, such as Call-Fleming syndrome. PMID:18923817

  2. Vasoconstriction Seen in Coronary Bypass Grafts During Handgrip in Humans

    PubMed Central

    Momen, Afsana; Gahremanpour, Amir; Mansoor, Ather; Kunselman, Allen; Blaha, Cheryl; Pae, Walter; Leuenberger, Urs A.; Sinoway, Lawrence I.

    2008-01-01

    In animal studies, sympathetically mediated coronary vasoconstriction has been demonstrated during exercise. Human studies examining coronary artery dynamics during exercise are technically difficult to perform. Recently, noninvasive transthoracic Duplex ultrasound studies demonstrated that: 1) patients with left internal mammary artery (LIMA) grafts to the left anterior descending artery can be imaged; and 2) the LIMA blood flow patterns are similar to those seen in normal coronary arteries. Accordingly, subjects with LIMA to the left anterior descending artery were studied during handgrip protocols as blood flow velocity in the LIMA was determined. Beat-by-beat analysis of changes in diastolic coronary blood flow velocity (CBV) was performed in six male clinically stable volunteers (60 ± 2 yrs) during two handgrip protocols. Arterial blood pressure (BP) and heart rate (HR) were also measured and an index of coronary vascular resistance (CVR) was calculated as diastolic BP/CBV). Fatiguing handgrip performed at (40% of maximal voluntary contraction; MVC) followed by circulatory arrest did not evoke an increase in CVR (P = NS). In protocol 2, short bouts of handgrip (15 s) led to increases in CVR (18 ± 3% at 50% MVC and 20 ± 8% at 70% MVC). BP was also increased during handgrip. Our results reveal that in conscious humans, coronary vasoconstriction occurs within 15 s of onset of static handgrip at intensities at or greater than 50% MVC. These responses are likely to be due to sympathetic vasoconstriction of the coronary circulation. PMID:17068218

  3. Classical transient receptor potential channel 6 (TRPC6) is essential for hypoxic pulmonary vasoconstriction and alveolar gas exchange

    PubMed Central

    Weissmann, Norbert; Dietrich, Alexander; Fuchs, Beate; Kalwa, Hermann; Ay, Mahmut; Dumitrascu, Rio; Olschewski, Andrea; Storch, Ursula; Mederos y Schnitzler, Michael; Ghofrani, Hossein Ardeschir; Schermuly, Ralph Theo; Pinkenburg, Olaf; Seeger, Werner; Grimminger, Friedrich; Gudermann, Thomas

    2006-01-01

    Regional alveolar hypoxia causes local vasoconstriction in the lung, shifting blood flow from hypoxic to normoxic areas, thereby maintaining gas exchange. This mechanism is known as hypoxic pulmonary vasoconstriction (HPV). Disturbances in HPV can cause life-threatening hypoxemia whereas chronic hypoxia triggers lung vascular remodeling and pulmonary hypertension. The signaling cascade of this vitally important mechanism is still unresolved. Using transient receptor potential channel 6 (TRPC6)-deficient mice, we show that this channel is a key regulator of acute HPV as this regulatory mechanism was absent in TRPC6−/− mice whereas the pulmonary vasoconstrictor response to the thromboxane mimetic U46619 was unchanged. Accordingly, induction of regional hypoventilation resulted in severe arterial hypoxemia in TRPC6−/− but not in WT mice. This effect was mirrored by a lack of hypoxia-induced cation influx and currents in smooth-muscle cells from precapillary pulmonary arteries (PASMC) of TRPC6−/− mice. In both WT and TRPC6−/− PASMC hypoxia caused diacylglycerol (DAG) accumulation. DAG seems to exert its action via TRPC6, as DAG kinase inhibition provoked a cation influx only in WT but not in TRPC6−/− PASMC. Notably, chronic hypoxia-induced pulmonary hypertension was independent of TRPC6 activity. We conclude that TRPC6 plays a unique and indispensable role in acute hypoxic pulmonary vasoconstriction. Manipulation of TRPC6 function may thus offer a therapeutic strategy for the control of pulmonary hemodynamics and gas exchange. PMID:17142322

  4. Cryotherapy-Induced Persistent Vasoconstriction After Cutaneous Cooling: Hysteresis Between Skin Temperature and Blood Perfusion.

    PubMed

    Khoshnevis, Sepideh; Craik, Natalie K; Matthew Brothers, R; Diller, Kenneth R

    2016-03-01

    The goal of this study was to investigate the persistence of cold-induced vasoconstriction following cessation of active skin-surface cooling. This study demonstrates a hysteresis effect that develops between skin temperature and blood perfusion during the cooling and subsequent rewarming period. An Arctic Ice cryotherapy unit (CTU) was applied to the knee region of six healthy subjects for 60 min of active cooling followed by 120 min of passive rewarming. Multiple laser Doppler flowmetry perfusion probes were used to measure skin blood flow (expressed as cutaneous vascular conductance (CVC)). Skin surface cooling produced a significant reduction in CVC (P < 0.001) that persisted throughout the duration of the rewarming period. In addition, there was a hysteresis effect between CVC and skin temperature during the cooling and subsequent rewarming cycle (P < 0.01). Mixed model regression (MMR) showed a significant difference in the slopes of the CVC-skin temperature curves during cooling and rewarming (P < 0.001). Piecewise regression was used to investigate the temperature thresholds for acceleration of CVC during the cooling and rewarming periods. The two thresholds were shown to be significantly different (P = 0.003). The results show that localized cooling causes significant vasoconstriction that continues beyond the active cooling period despite skin temperatures returning toward baseline values. The significant and persistent reduction in skin perfusion may contribute to nonfreezing cold injury (NFCI) associated with cryotherapy. PMID:26632263

  5. Brain Regions Underlying Word Finding Difficulties in Temporal Lobe Epilepsy

    ERIC Educational Resources Information Center

    Trebuchon-Da Fonseca, Agnes; Guedj, Eric; Alario, F-Xavier; Laguitton, Virginie; Mundler, Olivier; Chauvel, Patrick; Liegeois-Chauvel, Catherine

    2009-01-01

    Word finding difficulties are often reported by epileptic patients with seizures originating from the language dominant cerebral hemisphere, for example, in temporal lobe epilepsy. Evidence regarding the brain regions underlying this deficit comes from studies of peri-operative electro-cortical stimulation, as well as post-surgical performance.…

  6. Astrocyte Contributions to Flow/Pressure-Evoked Parenchymal Arteriole Vasoconstriction

    PubMed Central

    Kim, Ki Jung; Iddings, Jennifer A.; Stern, Javier E.; Blanco, Víctor M.; Croom, Deborah; Kirov, Sergei A.

    2015-01-01

    Basal and activity-dependent cerebral blood flow changes are coordinated by the action of critical processes, including cerebral autoregulation, endothelial-mediated signaling, and neurovascular coupling. The goal of our study was to determine whether astrocytes contribute to the regulation of parenchymal arteriole (PA) tone in response to hemodynamic stimuli (pressure/flow). Cortical PA vascular responses and astrocytic Ca2+ dynamics were measured using an in vitro rat/mouse brain slice model of perfused/pressurized PAs; studies were supplemented with in vivo astrocytic Ca2+ imaging. In vitro, astrocytes responded to PA flow/pressure increases with an increase in intracellular Ca2+. Astrocytic Ca2+ responses were corroborated in vivo, where acute systemic phenylephrine-induced increases in blood pressure evoked a significant increase in astrocytic Ca2+. In vitro, flow/pressure-evoked vasoconstriction was blunted when the astrocytic syncytium was loaded with BAPTA (chelating intracellular Ca2+) and enhanced when high Ca2+ or ATP were introduced to the astrocytic syncytium. Bath application of either the TRPV4 channel blocker HC067047 or purinergic receptor antagonist suramin blunted flow/pressure-evoked vasoconstriction, whereas K+ and 20-HETE signaling blockade showed no effect. Importantly, we found TRPV4 channel expression to be restricted to astrocytes and not the endothelium of PA. We present evidence for a novel role of astrocytes in PA flow/pressure-evoked vasoconstriction. Our data suggest that astrocytic TRPV4 channels are key molecular sensors of hemodynamic stimuli and that a purinergic, glial-derived signal contributes to flow/pressure-induced adjustments in PA tone. Together our results support bidirectional signaling within the neurovascular unit and astrocytes as key modulators of PA tone. PMID:26019339

  7. Neuropeptide Y antagonism reduces reflex cutaneous vasoconstriction in humans.

    PubMed

    Stephens, Dan P; Saad, Adham R; Bennett, Lee Ann T; Kosiba, Wojciech A; Johnson, John M

    2004-09-01

    Previous studies have provided evidence of a non-noradrenergic contributor to reflex cutaneous vasoconstriction in humans but did not identify the transmitter responsible. To test whether neuropeptide Y (NPY) has a role, in two series of experiments we slowly reduced whole body skin temperature (TSK) from 34.5 to 31.7 degrees C. In protocol 1, Ringer solution and the NPY receptor antagonist BIBP-3226 alone were delivered intradermally via microdialysis. In protocol 2, yohimbine plus propranolol (Yoh + Pro), Yoh + Pro in combination with BIBP-3226, and Ringer solution were delivered to antagonize locally the vasomotor effects of NPY and norepinephrine. Blood flow was measured by laser Doppler flowmetry (LDF). Mean arterial blood pressure (MAP) was monitored at the finger (Finapres). In protocol 1, cutaneous vascular conductance (CVC) fell by 45%, to 55.1 +/- 5.6% of baseline at control sites (P < 0.05). At BIBP-3226-treated sites, CVC fell by 34.1% to 65.9 +/- 5.0% (P < 0.05; P < 0.05 between sites). In protocol 2, during body cooling, CVC at control sites fell by 32.6%, to 67.4 +/- 4.3% of baseline; at sites treated with Yoh + Pro, CVC fell by 18.7%, to 81.3 +/- 4.4% of baseline (P < 0.05 vs. baseline; P < 0.05 vs. control) and did not fall significantly at sites treated with BIBP-3226 + Yoh + Pro (P > 0.05; P < 0.05 vs. other sites). After cooling, exogenous norepinephrine induced vasoconstriction at control sites (P < 0.05) but not at sites treated with Yoh + Pro + BIBP-3226 (P > 0.05). These results indicate that NPY participates in sympathetically mediated cutaneous vasoconstriction in humans during whole body cooling. PMID:15165988

  8. Reversible Cerebral Vasoconstriction Syndrome: A Report on Three Cases.

    PubMed

    Roongpiboonsopit, Duangnapa; Kongbunkiat, Kannikar; Phanthumchinda, Kammant

    2016-01-01

    Reversible cerebral vasoconstriction syndrome (RCVS), a recently recognized syndrome, is defined as an intermittent segmental vasospasm of cerebral arteries accompanied by thunderclap headache. The major complications of RCVS include ischemic or hemorrhagic stroke, which may cause morbidity and mortality. It is important to detect RCVS in clinical practice because misdiagnosis may lead to inappropriate treatment. In Thailand, there are only two reported cases of RCVS, which may reflect an underdiagnosis of this syndrome. To raise awareness of RCVS, we reported a case series of three RCVS cases. Two of the presented cases had interesting precipitating factors, and two cases had an unusual delayed clinical course. PMID:27455831

  9. Understanding Hypoxic Drive and the Release of Hypoxic Vasoconstriction.

    PubMed

    Inkrott, Jon C

    2016-01-01

    Understanding the hypoxic drive and release of hypoxic vasoconstriction in the chronic obstructive pulmonary disease population can be somewhat confusing and misunderstood. Furthermore, the hypoxic drive theory is one in which there really is no scientific evidence to support and yet continues to prosper in every aspect of care in regard to the chronic lung patient, from prehospital all the way to intensive care unit and home care therapy. This subject review will hopefully enhance some understanding of what exactly goes on with these patients and the importance of providing oxygen when it is desperately needed. PMID:27393755

  10. Reduced circulating endothelial progenitor cells in reversible cerebral vasoconstriction syndrome

    PubMed Central

    2014-01-01

    Background The pathophysiology of reversible cerebral vasoconstriction syndrome (RCVS) remains elusive. Endothelial dysfunction might play a role, but direct evidence is lacking. This study aimed to explore whether patients with RCVS have a reduced level of circulating circulating endothelial progenitor cells (EPCs) to repair the dysfunctional endothelial vasomotor control. Methods We prospectively recruited 24 patients with RCVS within one month of disease onset and 24 healthy age- and sex-matched controls. Flow cytometry was used to quantify the numbers of circulating EPCs, defined as KDR+CD133+, CD34+CD133+, and CD34+KDR+ double-positive mononuclear cells. The Lindegaard index, an index of vasoconstriction, was calculated by measuring the mean flow velocity of middle cerebral arteries and distal extracranial internal carotid arteries via color-coded sonography on the same day as blood drawing. A Lindegaard index of 2 was chosen as the cutoff value for significant vasoconstriction of middle cerebral arteries based on our previous study. Results Patients with RCVS had a reduced number of CD34+KDR+ cells (0.009 ± 0.006% vs. 0.014 ± 0.010%, p = 0.031) but not KDR+CD133+ cells or CD34+CD133+ EPCs, in comparison with controls. The number of CD34+KDR+ cells was inversely correlated with the Lindegaard index (rs = -0.418, p = 0.047). Of note, compared to controls, patients with a Lindegaard index > 2 (n = 13) had a reduced number of CD34+KDR+ cells (0.007 ± 0.005% vs. 0.014 ± 0.010%, p = 0.010), but those with a Lindegaard index ≤ 2 did not. Conclusions Patients with RCVS had reduced circulating CD34+KDR+ EPCs, which were correlated with the severity of vasoconstriction. Endothelial dysfunction might contribute to the pathogenesis of RCVS. PMID:25466718

  11. The role of Na(+), K(+)-ATPase in the hypoxic vasoconstriction in isolated rat basilar artery.

    PubMed

    Shen, Haitao; Liang, Peng; Qiu, Suhua; Zhang, Bo; Wang, Yongli; Lv, Ping

    2016-06-01

    Hypoxia-induced cerebrovascular dysfunction is a key factor in the occurrence and the development of cerebral ischemia. Na(+), K(+)-ATPase affects the regulation of intracellular Ca(2+) concentration and plays an important role in vascular smooth muscle function. However, the potential role of Na(+), K(+)-ATPase in hypoxia-induced cerebrovascular dysfunction is unknown. In this study, we found that the KCl-induced contraction under hypoxia in rat endothelium-intact basilar arteries is similar to that of denuded arteries, suggesting that hypoxia may cause smooth muscle cell (SMC)-dependent vasoconstriction in the basilar artery. The Na(+), K(+)-ATPase activity of the isolated basilar artery with or without endothelium significantly reduced with prolonged hypoxia. Blocking the Na(+)-Ca(2+) exchanger with Ni(2+) (10(-3)M) or the L-type Ca(2+) channel with nimodipine (10(-8)M) dramatically attenuated KCl-induced contraction under hypoxia. Furthermore, prolonged hypoxia significantly reduced Na(+), K(+)-ATPase activity and increased [Ca(2+)]i in cultured rat basilar artery SMCs. Hypoxia reduced the protein and mRNA expression of the α2 isoform of Na(+), K(+)-ATPase in SMCs in vitro. We used a low concentration of the Na(+), K(+)-ATPase inhibitor ouabain, which possesses a high affinity for the α2 isoform. The contractile response in the rat basilar artery under hypoxia was partly inhibited by ouabain pretreatment. The decreased Na(+), K(+)-ATPase activity in isolated basilar artery and the increased [Ca(2+)]i in SMCs induced by hypoxia were partly inhibited by pretreatment with a low concentration of ouabain. These results suggest that hypoxia may educe Na(+), K(+)-ATPase activity in SMCs through the α2 isoform contributing to vasoconstriction in the rat basilar artery. PMID:26924456

  12. Functional Segregation of Cortical Regions Underlying Speech Timing and Articulation.

    PubMed

    Long, Michael A; Katlowitz, Kalman A; Svirsky, Mario A; Clary, Rachel C; Byun, Tara McAllister; Majaj, Najib; Oya, Hiroyuki; Howard, Matthew A; Greenlee, Jeremy D W

    2016-03-16

    Spoken language is a central part of our everyday lives, but the precise roles that individual cortical regions play in the production of speech are often poorly understood. To address this issue, we focally lowered the temperature of distinct cortical regions in awake neurosurgical patients, and we relate this perturbation to changes in produced speech sequences. Using this method, we confirm that speech is highly lateralized, with the vast majority of behavioral effects seen on the left hemisphere. We then use this approach to demonstrate a clear functional dissociation between nearby cortical speech sites. Focal cooling of pars triangularis/pars opercularis (Broca's region) and the ventral portion of the precentral gyrus (speech motor cortex) resulted in the manipulation of speech timing and articulation, respectively. Our results support a class of models that have proposed distinct processing centers underlying motor sequencing and execution for speech. PMID:26924439

  13. Vasoconstriction in horses caused by endophyte-infected tall fescue seed is detected with Doppler ultrasonography

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The hypotheses that endophyte (Neotyphodium coenophialum)-infected tall fescue (TF) seed causes vasoconstriction in horses in vivo and that ground seed would cause more pronounced vasoconstriction than whole seed were tested. Ten horses each received 1 of 3 treatments: endophyte-free ground (E–G; n ...

  14. Adrenergic vasoconstriction in peripheral nerves of the rabbit

    SciTech Connect

    Selander, D.; Mansson, L.G.; Karlsson, L.; Svanvik, J.

    1985-01-01

    The blood flow in the sciatic nerve of the rabbit was estimated from the wash out of intraneurally injected /sup 133/Xe. To avoid diffusion of the tracer into the surrounding muscular tissue, the nerve was covered by a gas-tight plastic film. Using this technique, the basal blood flow in the sciatic nerve was estimated to 35 ml X min-1 X 100 g-1. It was found that intraarterial norepinephrine and electrical stimulation of the lumbar sympathetic chain strongly reduced the wash out of /sup 133/Xe, which only can be explained by a pronounced reduction of the blood flow in the nerve itself. The blood flow again increased within 4 min of stopping the infusion of norepinephrine or the sympathetic stimulation. The prolonged effect and higher neurotoxicity of local anesthetics containing adrenaline may be explained by an alpha receptor-mediated vasoconstriction of the microvessels of peripheral nerves.

  15. Magnesium for Treatment of Reversible Cerebral Vasoconstriction Syndrome

    PubMed Central

    Mijalski, Christina; Dakay, Katarina; Miller-Patterson, Cameron; Saad, Ali; Silver, Brian

    2015-01-01

    We describe 2 cases of reversible cerebral vasoconstriction syndrome (RCVS) with refractory headache aborted by intravenous magnesium. Case 1 is a 53-year-old woman with subarachnoid hemorrhage due to RCVS presented with refractory headache and persistent vasospasm, despite aggressive treatment with calcium channel blockers (CCBs) and systemic corticosteroids. Subsequently, she experienced dramatic relief of symptoms with intravenous magnesium therapy. She continued oral maintenance therapy and remained symptom free. Case 2 is a 71-year-old female with bilateral temporo-occipital infarcts due to RCVS, presented with refractory headache and persistent vasospasm on transcranial Doppler (TCD), despite aggressive treatment with CCBs. She experienced dramatic relief of symptoms with intravenous magnesium and resolution of vasospasm on TCD. Magnesium may be beneficial for the treatment of refractory headaches in patients with RCVS. Future studies are needed to determine whether it should be considered as a first-line agent. PMID:27366294

  16. Obesity and risk of vascular disease: importance of endothelium-dependent vasoconstriction

    PubMed Central

    Barton, Matthias; Baretella, Oliver; Meyer, Matthias R

    2012-01-01

    Obesity has become a serious global health issue affecting both adults and children. Recent devolopments in world demographics and declining health status of the world's population indicate that the prevalence of obesity will continue to increase in the next decades. As a disease, obesity has deleterious effects on metabolic homeostasis, and affects numerous organ systems including heart, kidney and the vascular system. Thus, obesity is now regarded as an independent risk factor for atherosclerosis-related diseases such as coronary artery disease, myocardial infarction and stroke. In the arterial system, endothelial cells are both the source and target of factors contributing to atherosclerosis. Endothelial vasoactive factors regulate vascular homeostasis under physiological conditions and maintain basal vascular tone. Obesity results in an imbalance between endothelium-derived vasoactive factors favouring vasoconstriction, cell growth and inflammatory activation. Abnormal regulation of these factors due to endothelial cell dysfunction is both a consequence and a cause of vascular disease processes. Finally, because of the similarities of the vascular pathomechanisms activated, obesity can be considered to cause accelerated, ‘premature’ vascular aging. Here, we will review some of the pathomechanisms involved in obesity-related activation of endothelium-dependent vasoconstriction, the clinical relevance of obesity-associated vascular risk, and therapeutic interventions using ‘endothelial therapy’ aiming at maintaining or restoring vascular endothelial health. LINKED ARTICLES This article is part of a themed section on Fat and Vascular Responsiveness. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2012.165.issue-3 PMID:21557734

  17. Continuous detection of cerebral vasodilatation and vasoconstriction using intracranial pulse morphological template matching.

    PubMed

    Asgari, Shadnaz; Gonzalez, Nestor; Subudhi, Andrew W; Hamilton, Robert; Vespa, Paul; Bergsneider, Marvin; Roach, Robert C; Hu, Xiao

    2012-01-01

    Although accurate and continuous assessment of cerebral vasculature status is highly desirable for managing cerebral vascular diseases, no such method exists for current clinical practice. The present work introduces a novel method for real-time detection of cerebral vasodilatation and vasoconstriction using pulse morphological template matching. Templates consisting of morphological metrics of cerebral blood flow velocity (CBFV) pulse, measured at middle cerebral artery using Transcranial Doppler, are obtained by applying a morphological clustering and analysis of intracranial pulse algorithm to the data collected during induced vasodilatation and vasoconstriction in a controlled setting. These templates were then employed to define a vasodilatation index (VDI) and a vasoconstriction index (VCI) for any inquiry data segment as the percentage of the metrics demonstrating a trend consistent with those obtained from the training dataset. The validation of the proposed method on a dataset of CBFV signals of 27 healthy subjects, collected with a similar protocol as that of training dataset, during hyperventilation (and CO₂ rebreathing tests) shows a sensitivity of 92% (and 82%) for detection of vasodilatation (and vasoconstriction) and the specificity of 90% (and 92%), respectively. Moreover, the proposed method of detection of vasodilatation (vasoconstriction) is capable of rejecting all the cases associated with vasoconstriction (vasodilatation) and outperforms other two conventional techniques by at least 7% for vasodilatation and 19% for vasoconstriction. PMID:23226385

  18. Continuous Detection of Cerebral Vasodilatation and Vasoconstriction Using Intracranial Pulse Morphological Template Matching

    PubMed Central

    Asgari, Shadnaz; Gonzalez, Nestor; Subudhi, Andrew W.; Hamilton, Robert; Vespa, Paul; Bergsneider, Marvin; Roach, Robert C.; Hu, Xiao

    2012-01-01

    Although accurate and continuous assessment of cerebral vasculature status is highly desirable for managing cerebral vascular diseases, no such method exists for current clinical practice. The present work introduces a novel method for real-time detection of cerebral vasodilatation and vasoconstriction using pulse morphological template matching. Templates consisting of morphological metrics of cerebral blood flow velocity (CBFV) pulse, measured at middle cerebral artery using Transcranial Doppler, are obtained by applying a morphological clustering and analysis of intracranial pulse algorithm to the data collected during induced vasodilatation and vasoconstriction in a controlled setting. These templates were then employed to define a vasodilatation index (VDI) and a vasoconstriction index (VCI) for any inquiry data segment as the percentage of the metrics demonstrating a trend consistent with those obtained from the training dataset. The validation of the proposed method on a dataset of CBFV signals of 27 healthy subjects, collected with a similar protocol as that of training dataset, during hyperventilation (and CO2 rebreathing tests) shows a sensitivity of 92% (and 82%) for detection of vasodilatation (and vasoconstriction) and the specificity of 90% (and 92%), respectively. Moreover, the proposed method of detection of vasodilatation (vasoconstriction) is capable of rejecting all the cases associated with vasoconstriction (vasodilatation) and outperforms other two conventional techniques by at least 7% for vasodilatation and 19% for vasoconstriction. PMID:23226385

  19. Topical retinoic acid does not alter the vasoconstrictive properties of topical corticosteroids in humans.

    PubMed

    Schmied, C; Saurat, J H

    1991-01-01

    Dermo-epidermal atrophy is one of the main side effects of long-term treatment with topical corticosteroids. Retinoic acid may prevent and even reverse these effects in animals. Extension of this concept to therapy in humans implies that several studies have been performed; among others, it has to be established that treatment with topical retinoic acid does not interfere with the anti-inflammatory action of topical corticosteroids. The present study on the cutaneous vasoconstriction test comprised two different double-blind approaches: (i) vasoconstriction tests with betamethasone dipropionate (Diprolene) and clobetasone butyrate (Emovate) were carried out on skin that had previously been treated for 10 days with retinoic acid 0.01, 0.025 or 0.05% (or excipient); (ii) vasoconstriction tests with a combination of triamcinolone acetonide 0.1% and retinoic acid 0.025% were compared with triamcinolone acetonide 0.1% alone. Pretreatment for 10 days with retinoic acid did not alter the vasoconstriction induced by corticosteroids: no decrease or increase in the vasoconstriction score was observed, whether the skin had been previously treated with retinoic acid or with excipient. The vasoconstriction scores obtained with a combination of retinoic acid and triamcinolone acetonide were identical with those obtained with the steroid alone. This study indicates that retinoic acid does not inhibit the vasoconstriction induced by topical corticosteroids and suggests that the anti-inflammatory effect of the latter should be maintained in association with retinoic acid. PMID:2050230

  20. No protective role for hypoxic pulmonary vasoconstriction in severe hypergravity-induced arterial hypoxemia.

    PubMed

    Karlsson, Lars L; Rohdin, Malin; Nekludov, Michael; Ax, Malin; Petersson, Johan

    2011-09-01

    Supine subjects exposed to hypergravity show a marked arterial desaturation. Previous work from our laboratory has also shown a paradoxical reduction of lung perfusion in dependent lung regions in supine subjects exposed to hypergravity. We reasoned that the increased lung weight during hypergravity caused either direct compression of the blood vessels in the dependent lung tissue or that poor regional ventilation caused reduced perfusion through hypoxic pulmonary vasoconstriction (HPV). The objective of this study was to evaluate the importance of HPV through measurements of arterial oxygenation during exposure to hypergravity with normal and attenuated HPV. A further increased arterial desaturation during hypergravity with attenuated HPV would support the hypothesis that HPV contributes to the paradoxical redistribution of regional perfusion. In a two-phased randomized study we first exposed 12 healthy subjects to 5 G while supine during two single-blinded conditions; control and after 50 mg sildenafil p.o.. In a second phase, 12 supine subjects were exposed to 5 G during three single-blinded conditions; control, after 100 mg sildenafil p.o. and after inhalation of 10 μg iloprost. There was a substantial arterial desaturation by 5-30% units in all subjects with no or only minor differences between conditions. The results speak against HPV as a principal mechanism for the hypergravity-induced reduction of lung perfusion in dependent lung regions in supine humans. PMID:21274557

  1. The effect of PCO2 on hypoxic pulmonary vasoconstriction.

    PubMed

    Noble, W H; Kay, J C; Fisher, J A

    1981-09-01

    Lung areas with a low V/Q ratio cause hypoxaemia. The low alveolar oxygen concentration may cause local hypoxic pulmonary vasoconstriction (HPV) which reduces perfusion, raises the V/Q ratio, and hence reduces the tendency to a low PaO2. By changing PCO2, the HPV response can be altered. We examined this relationship in anaesthetized dogs by using a tracheal divider to separate hypoxic (nitrogen ventilated) from oxygenated (100 per cent oxygen ventilated) lung. Relative perfusion was assessed from total 133Xe exhaled from each lung area after intravenous infusions. When PaCO2 was changed by changing ventilation, we found that an increasing PaCO2 increased HPV and also PaO2. At a PaCO2 of 3.3 kPa, HPV was abolished and PaO2 fell. We also changed PaCO2 by altering PICO2 to one or both lung areas while ventilation remained constant throughout the experiment. Again as PaCO2 increased, HPV and PaCO2 increased. When PaCO2 fell and end tidal carbon dioxide in the hypoxic lung (PETCO2) remained elevated by maintaining PICO2 in the hypoxic lung and removing CO2 from the oxygenated lung) HPV was maintained. Thus it is the alveolar concentration of CO2 in the hypoxic lung which is important in modifying HPV. We conclude that in this model a low PETCO2 (3.3 kPa) in hypoxic lung will reduce HPV, and will result in more severe hypoxaemia. This may have relevance in both anaesthetized and intensive care unit patients when a higher PaO2 may be obtained by increasing hypoxic lung PETCO2. The effect of PETCO2 on PaO2 will be influenced by other variables, but when hypoventilated or hypoxic exist, increasing PETCO2 may reinforce hypoxic pulmonary vasoconstriction and thus may increase PaO2. PMID:6793220

  2. Increased Hepato-Splanchnic Vasoconstriction in Diabetics during Regular Hemodialysis

    PubMed Central

    Ribitsch, Werner; Schneditz, Daniel; Franssen, Casper F. M.; Schilcher, Gernot; Stadlbauer, Vanessa; Horina, Jörg H.; Rosenkranz, Alexander R.

    2015-01-01

    Background and Objectives Ultrafiltration (UF) of excess fluid activates numerous compensatory mechanisms during hemodialysis (HD). The increase of both total peripheral and splanchnic vascular resistance is considered essential in maintaining hemodynamic stability. The aim of this study was to evaluate the extent of UF-induced changes in hepato-splanchnic blood flow and resistance in a group of maintenance HD patients during regular dialysis. Design, Setting, Participants, & Measurements Hepato-splanchnic flow resistance index (RI) and hepato-splanchnic perfusion index (QI) were measured in 12 chronic HD patients using a modified, non-invasive Indocyaningreen (ICG) dilution method. During a midweek dialysis session we determined RI, QI, ICG disappearance rate (kICG), plasma volume (Vp), hematocrit (Hct), mean arterial blood pressure (MAP) and heart rate (HR) at four times in hourly intervals (t1 to t4). Dialysis settings were standardized and all patient studies were done in duplicate. Results In the whole study group mean UF volume was 1.86 ± 0.46 L, Vp dropped from 3.65 ± 0.77L at t1 to 3.40 ± 0.78L at t4, and all patients remained hemodynamically stable. In all patients RI significantly increased from 12.40 ± 4.21 mmHg∙s∙m2/mL at t1 to 14.94 ± 6.36 mmHg∙s∙m2/mL at t4 while QI significantly decreased from 0.61 ± 0.22 at t1 to 0.52 ± 0.20 L/min/m2 at t4, indicating active vasoconstriction. In diabetic subjects, however, RI was significantly larger than in non-diabetics at all time points. QI was lower in diabetic subjects. Conclusions In chronic HD-patients hepato-splanchnic blood flow substantially decreases during moderate UF as a result of an active splanchnic vasoconstriction. Our data indicate that diabetic HD-patients are particularly prone to splanchnic ischemia and might therefore have an increased risk for bacterial translocation, endotoxemia and systemic inflammation. PMID:26713734

  3. Reversible Cerebral Vasoconstriction Syndrome, Part 2: Diagnostic Work-Up, Imaging Evaluation, and Differential Diagnosis.

    PubMed

    Miller, T R; Shivashankar, R; Mossa-Basha, M; Gandhi, D

    2015-09-01

    The diagnostic evaluation of a patient with reversible cerebral vasoconstriction syndrome integrates clinical, laboratory, and radiologic findings. Imaging plays an important role by confirming the presence of cerebral vasoconstriction; monitoring potential complications such as ischemic stroke; and suggesting alternative diagnoses, including CNS vasculitis and aneurysmal subarachnoid hemorrhage. Noninvasive vascular imaging, including transcranial Doppler sonography and MR angiography, has played an increasingly important role in this regard, though conventional angiography remains the criterion standard for the evaluation of cerebral artery vasoconstriction. Newer imaging techniques, including high-resolution vessel wall imaging, may help in the future to better discriminate reversible cerebral vasoconstriction syndrome from primary angiitis of the CNS, an important clinical distinction. PMID:25614476

  4. Tall fescue alkaloids cause vasoconstriction in equine medial palmar artery and vein

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mares grazing endophyte-infected (Neotyphodium coenophialum) tall fescue (Lolium arundinaceum) typically exhibit reproductive dysfunction rather than peripheral vasoconstriction as a primary sign of the fescue toxicosis syndrome. Recent work using Doppler ultrasonography demonstrated that consumptio...

  5. 10 CFR 500.3 - Electric regions-electric region groupings for reliability measurements under the Powerplant and...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Electric regions-electric region groupings for reliability measurements under the Powerplant and Industrial Fuel Use Act of 1978. 500.3 Section 500.3 Energy DEPARTMENT OF ENERGY (CONTINUED) ALTERNATE FUELS DEFINITIONS § 500.3 Electric regions—electric region groupings for reliability measurements under...

  6. Ginsenoside Rg1 attenuates hypoxia and hypercapnia-induced vasoconstriction in isolated rat pulmonary arterial rings by reducing the expression of p38

    PubMed Central

    Zheng, Mengxiao; Zhao, Meiping; Tang, Lanlan; Zhang, Congcong; Song, Longsheng

    2016-01-01

    Background Pulmonary arterial hypertension (PAH) is a fatal disease characterized by increased pulmonary arteriolar resistance. Pulmonary vasoconstriction has been proved to play a significant role in PAH. We previously reported that Panax notoginseng saponins (PNS) might attenuate hypoxia and hypercapnia-induced pulmonary vasoconstriction (HHPV). Methods In the present study, our specific objective was to investigate the role of ginsenoside Rg1, a major component of PNS, in this process and the possible underlying mechanism. The second order pulmonary rings isolated from the Sprague-Dawley rats were treated with different dosage of ginsenoside Rg1 at 8, 40, or 100 mg/L respectively, both before and during the conditions of hypoxia and hypercapnia. Contractile force changes of the rings were detected. Furthermore, SB203580, the selective inhibitor for p38 activation was applied to the rings. Pulmonary arterial smooth muscle cells (PASMCs) were cultured under hypoxic and hypercapnic conditions, and ginsenoside Rg1 was administered to detect the changes induced by p38. Results Under the hypoxic and hypercapnic conditions, we observed a biphasic pulmonary artery contractile response to the second pulmonary artery rings. It is hypothesized that the observed attenuation of vasoconstriction and the production of vasodilation could have been induced by ginsenoside Rg1. This effect was significantly reinforced by SB203580 (P<0.05 or P<0.01). The expression of p38 in the PASMCs under hypoxic and hypercapnic conditions was significantly activated (P<0.05 or P<0.01) and the observed activation was attenuated by ginsenoside Rg1 (P<0.05 or P<0.01). Conclusions Our findings strongly support the significant role of ginsenoside Rg1 in the inhibition of hypoxia and hypercapnia-induced vasoconstriction by the p38 pathway. PMID:27499938

  7. Dexmedetomidine inhibits vasoconstriction via activation of endothelial nitric oxide synthase.

    PubMed

    Nong, Lidan; Ma, Jue; Zhang, Guangyan; Deng, Chunyu; Mao, Songsong; Li, Haifeng; Cui, Jianxiu

    2016-09-01

    Despite the complex vascular effects of dexmedetomidine (DEX), its actions on human pulmonary resistance arteries remain unknown. The present study tested the hypothesis that DEX inhibits vascular tension in human pulmonary arteries through the endothelial nitric oxide synthase (eNOS) mediated production of nitric oxide (NO). Pulmonary artery segments were obtained from 62 patients who underwent lung resection. The direct effects of DEX on human pulmonary artery tension and changes in vascular tension were determined by isometric force measurements recorded on a myograph. Arterial contractions caused by increasing concentrations of serotonin with DEX in the presence or absence of L-NAME (endothelial nitric oxide synthase inhibitor), yohimbine (α2-adrenoceptor antagonist) and indomethacin (cyclooxygenase inhibitor) as antagonists were also measured. DEX had no effect on endothelium-intact pulmonary arteries, whereas at concentrations of 10(-8)~10(-6) mol/L, it elicited contractions in endothelium-denuded pulmonary arteries. DEX (0.3, 1, or 3×10(-9) mmol/L) inhibited serotonin-induced contraction in arteries with intact endothelium in a dose-dependent manner. L-NAME and yohimbine abolished DEX-induced inhibition, whereas indomethacin had no effect. No inhibitory effect was observed in endothelium-denuded pulmonary arteries. DEX-induced inhibition of vasoconstriction in human pulmonary arteries is mediated by NO production induced by the activation of endothelial α2-adrenoceptor and nitric oxide synthase. PMID:27610030

  8. Dexmedetomidine inhibits vasoconstriction via activation of endothelial nitric oxide synthase

    PubMed Central

    Nong, Lidan; Ma, Jue; Zhang, Guangyan; Deng, Chunyu; Mao, Songsong; Li, Haifeng

    2016-01-01

    Despite the complex vascular effects of dexmedetomidine (DEX), its actions on human pulmonary resistance arteries remain unknown. The present study tested the hypothesis that DEX inhibits vascular tension in human pulmonary arteries through the endothelial nitric oxide synthase (eNOS) mediated production of nitric oxide (NO). Pulmonary artery segments were obtained from 62 patients who underwent lung resection. The direct effects of DEX on human pulmonary artery tension and changes in vascular tension were determined by isometric force measurements recorded on a myograph. Arterial contractions caused by increasing concentrations of serotonin with DEX in the presence or absence of L-NAME (endothelial nitric oxide synthase inhibitor), yohimbine (α2-adrenoceptor antagonist) and indomethacin (cyclooxygenase inhibitor) as antagonists were also measured. DEX had no effect on endothelium-intact pulmonary arteries, whereas at concentrations of 10–8~10–6 mol/L, it elicited contractions in endothelium-denuded pulmonary arteries. DEX (0.3, 1, or 3×10–9 mmol/L) inhibited serotonin-induced contraction in arteries with intact endothelium in a dose-dependent manner. L-NAME and yohimbine abolished DEX-induced inhibition, whereas indomethacin had no effect. No inhibitory effect was observed in endothelium-denuded pulmonary arteries. DEX-induced inhibition of vasoconstriction in human pulmonary arteries is mediated by NO production induced by the activation of endothelial α2-adrenoceptor and nitric oxide synthase. PMID:27610030

  9. Splanchnic vasoconstriction in hyperthermic man - Role of falling blood pressure.

    NASA Technical Reports Server (NTRS)

    Rowell, L. B.; Profant, G. R.; Wyss, C.; Detry, J.-M. R.

    1971-01-01

    Results of a study in which six supine resting subjects, wearing water-perfused suits, had body skin temperature controlled at 35 C for 30 min (control period), then rapidly increased to 40.5 C for 43 to 50 min (heating period) in a two-part experiment. In the first part of the experiment arterial mean pressure (MP) in three men was increased back to, or above control levels at the 30 to 35th min of heating by total occlusion of both legs for 8 to 10 min. Splanchnic blood flow (SBF), which had fallen from 1.4 to 0.9 L/min at occlusion, rose only 0.05 L/min during occlusion. Splanchnic vascular resistance (SVR) rose throughout heating and occlusion. In the second part of the experiment (three men) SBF fell despite a spontaneous rise in MP and aortic pulse pressure prior to leg occlusion. Cardiac output (CO) was measured just before, during and after occlusion. Occlusion raised MP 10 to 15 mm Hg and reduced CO only slightly. It is concluded that falling MP or aortic pulse pressure are not major causes of the splanchnic vasoconstriction in response to heating man.

  10. Obstructive apnea during sleep is associated with peripheral vasoconstriction

    NASA Technical Reports Server (NTRS)

    Imadojemu, Virginia A.; Gleeson, Kevin; Gray, Kristen S.; Sinoway, Lawrence I.; Leuenberger, Urs A.

    2002-01-01

    Obstructive apnea during sleep is associated with a substantial transient blood pressure elevation. The mechanism of this pressor response is unclear. In this study we measured muscle sympathetic nerve activity (MSNA), mean arterial pressure (Psa), and mean limb blood velocity as an index of blood flow (MBV, Doppler) and calculated changes in limb vascular resistance during and after apneas during both wakefulness and sleep in patients with the obstructive sleep apnea syndrome. Immediately postapnea during sleep Psa increased significantly compared with the earlier stages of apnea and this was preceded by a rise of MSNA (n = 5). In contrast to blood pressure, MBV remained unchanged. Because resistance = blood pressure/blood flow, limb vascular resistance increased by 29 +/- 8% from late apnea to postapnea (n = 7, p < 0.002). Voluntary breathhold maneuvers during room air exposure evoked similar responses (n = 10). Supplemental oxygen administered via nonrebreather face mask attenuated the MSNA and vasoconstrictor responses to obstructive (n = 2) and voluntary apneas (n = 10). Our data suggest that obstructive apneas in patients with the obstructive apnea syndrome are accompanied by transient limb vasoconstriction. This vasoconstrictor response appears to be, at least in part, mediated by the sympathetic nervous system and may be linked to hypoxia.

  11. FMLP provokes coronary vasoconstriction and myocardial ischemia in rabbits

    SciTech Connect

    Gillespie, M.N.; Booth, D.C.; Friedman, B.J.; Cunningham, M.R.; Jay, M.; De Maria, A.N. )

    1988-03-01

    Recent pathological studies of coronary arteries from humans with suspected coronary spasm have revealed an augmented intramural burden of inflammatory cells. To test the hypothesis than inappropriate activation of inflammatory cells participates in the evolution of coronary vasospasm, the present experiment employed a newly developed coronary arteriographic technique for use in pentobarbital-anesthetized rabbits to evaluate the coronary vasomotor actions of the nonselective inflammatory cell stimulant, N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP). In 10 of 10 animals, selective left intracoronary injection of 200 ng fMLP evoked profound left coronary narrowing accompanied in all cases by ST segment deviation and dysrhythmias. Thallium-201 scintigraphy demonstrated hypoperfusion of the left ventricular free wall and septum supplied by the spastic coronary artery. The fMLP-induced epicardial vasoconstriction, ischemic electrocardiogram (ECG) changes, and thallium perfusion defects were reversed by intravenous nitroglycerin. Neither the right coronary artery nor its distribution were influenced by left coronary injection of fMLP. Additional experiments in isolated, salt solution-perfused rabbit hearts demonstrated that fMLP failed to exert direct coronary vasoconstrictor effects. These observations indicate that the nonselective inflammatory cell stimulant, fMLP, provokes arteriographically demonstrable coronary spasm with attendant myocardial hypoperfusion and ischemic ECG changes in anesthetized rabbits. Such a model may be useful in exploring the dynamic role of inflammatory cells in development of coronary spasm.

  12. Reversible Cerebral Vasoconstriction Syndrome Without Typical Thunderclap Headache.

    PubMed

    Wolff, Valérie; Ducros, Anne

    2016-04-01

    Reversible cerebral vasoconstriction syndrome (RCVS) is characterized by severe headache and diffuse segmental intracranial arterial constriction that resolve within three months. Stroke, which is the major complication of RCVS, can result in persistent neurological disability, and rarely causes death. Diagnosis of RCVS early in the clinical course might improve outcomes. Although recurrent thunderclap headache is the clinical hallmark of RCVS, the absence of such a pattern should not lead to discard the diagnosis. Our literature review shows that RCVS can also manifest as an unspecific headache, such as a single severe headache episode, a mild or a progressive headache. Moreover, a subset of patients with severe RCVS presents without any headache, but frequently with seizures, focal neurological deficits, confusion or coma, in the setting of stroke or posterior reversible encephalopathy syndrome. These patients may be aphasic or in comatose state, explaining their inability to give their own medical history. They may have forgotten the headache they had a few days before more dramatic symptoms, or may have a variant of the classical RCVS. By consequence, an RCVS should be suspected in patients with any unusual headache, whether thunderclap or not, and in patients with cryptogenic stroke or convexity subarachnoid hemorrhage, whether the patient also has headache or not. Diagnosis in such cases relies on the demonstration of reversible multifocal intracranial arterial stenosis and the exclusion of other causes. PMID:27016378

  13. Involvement of endothelin-1 in hypoxic pulmonary vasoconstriction in the lamb.

    PubMed Central

    Wang, Y; Coe, Y; Toyoda, O; Coceani, F

    1995-01-01

    1. Using isolated pulmonary resistance vessels from mature fetal lamb and chronically instrumented lambs (8-17 days old), we have examined whether hypoxic pulmonary vasoconstriction is sustained by activation of a constrictor mechanism or suppression of a dilator mechanism. 2. Hypoxia contracted both arteries and veins in vitro, and the contraction was greater with the former. After removing the endothelium, arteries responded faster to hypoxia, but the magnitude of the response remained unchanged. 3. Hypoxic arteries, unlike normally oxygenated arteries, did not contract with either indomethacin (2.8 microM) or N omega-nitro-L-arginine methyl ester (L-NAME, 100 microM). The same vessels relaxed with sodium nitroprusside (SNP, 0.001-10 microM) but not with bradykinin (0.1-100 nM). 4. Endothelin-1 (ET-1, 0.01-10 nM) contracted isolated arteries and veins under normoxic and hypoxic conditions. In both vessels, the contraction was fast in onset and subsidence, and was inhibited by the ETA receptor antagonist BQ123 (1 microM). The ET-1 precursor, big ET-1 (100 nM), also contracted arteries and veins, but compared with ET-1 its action was slower in development. Big ET-1 contraction, unlike ET-1 contraction, was curtailed by the inhibitor of the ET-1-converting enzyme, phosphoramidon (50 microM). 5. ET-1 (0.1-10 nM) had no effect on isolated arteries precontracted with a thromboxane A2 (TXA2) analogue (ONO-11113) and treated with BQ123 (10 microM). Under the same conditions, ET-1 relaxed the veins. Accordingly, in the absence of BQ123 treatment, the selective ETB receptor agonist IRL-1620 (0.1-100 nM) relaxed the contracted veins but not the arteries. 6. BQ123 (10 microM) inhibited the constriction of isolated arteries and veins to hypoxia. Likewise, in the conscious lamb a bolus of BQ123 (0.4 mg kg-1, injected into the pulmonary artery) curtailed the rise in pulmonary vascular resistance (Rpa) brought about by alveolar hypoxia without changing significantly systemic

  14. Blunted Hypoxic Pulmonary Vasoconstriction in Experimental Neonatal Chronic Lung Disease

    PubMed Central

    Rey-Parra, Gloria Juliana; Archer, Stephen L.; Bland, Richard D.; Albertine, Kurt H.; Carlton, David P.; Cho, Soo-Chul; Kirby, Beth; Haromy, Al; Eaton, Farah; Wu, Xichen; Thébaud, Bernard

    2008-01-01

    Rationale: Neonatal chronic lung disease (CLD), caused by prolonged mechanical ventilation (MV) with O2-rich gas, is the most common cause of long-term hospitalization and recurrent respiratory illness in extremely premature infants. Recurrent episodes of hypoxemia and associated ventilator adjustments often lead to worsening CLD. The mechanism that causes these hypoxemic episodes is unknown. Hypoxic pulmonary vasoconstriction (HPV), which is partially controlled by O2-sensitive voltage-gated potassium (Kv) channels, is an important adaptive response to local hypoxia that helps to match perfusion and ventilation in the lung. Objectives: To test the hypothesis that chronic lung injury (CLI) impairs HPV. Methods: We studied preterm lambs that had MV with O2-rich gas for 3 weeks and newborn rats that breathed 95%-O2 for 2 weeks, both of which resulted in airspace enlargement and pulmonary vascular changes consistent with CLD. Measurements and Main Results: HPV was attenuated in preterm lambs with CLI after 2 weeks of MV and in newborn rats with CLI after 2 weeks of hyperoxia. HPV and constriction to the Kv1.x-specific inhibitor, correolide, were preferentially blunted in excised distal pulmonary arteries (dPAs) from hyperoxic rats, whose dPAs exhibited decreased Kv1.5 and Kv2.1 mRNA and K+ current. Intrapulmonary gene transfer of Kv1.5, encoding the ion channel that is thought to trigger HPV, increased O2-sensitive K+ current in cultured smooth muscle cells from rat dPAs, and restored HPV in hyperoxic rats. Conclusions: Reduced expression/activity of O2-sensitive Kv channels in dPAs contributes to blunted HPV observed in neonatal CLD. PMID:18511704

  15. Hypoxic pulmonary vasoconstriction as a contributor to response in acute pulmonary embolism.

    PubMed

    Burrowes, K S; Clark, A R; Wilsher, M L; Milne, D G; Tawhai, M H

    2014-08-01

    Hypoxic pulmonary vasoconstriction (HPV) is an adaptive response unique to the lung whereby blood flow is diverted away from areas of low alveolar oxygen to improve ventilation-perfusion matching and resultant gas exchange. Some previous experimental studies have suggested that the HPV response to hypoxia is blunted in acute pulmonary embolism (APE), while others have concluded that HPV contributes to elevated pulmonary blood pressures in APE. To understand these contradictory observations, we have used a structure-based computational model of integrated lung function in 10 subjects to study the impact of HPV on pulmonary hemodynamics and gas exchange in the presence of regional arterial occlusion. The integrated model includes an experimentally-derived model for HPV. Its function is validated against measurements of pulmonary vascular resistance in normal subjects at four levels of inspired oxygen. Our results show that the apparently disparate observations of previous studies can be explained within a single model: the model predicts that HPV increases mean pulmonary artery pressure in APE (by 8.2 ± 7.0% in these subjects), and concurrently shows a reduction in response to hypoxia in the subjects who have high levels of occlusion and therefore maximal HPV in normoxia. PMID:24770844

  16. Vasoconstrictive effects of levobupivacaine on the basilar artery in the rabbit

    PubMed Central

    Ergil, Julide; Kertmen, Hayri; Sayın, Murat; Yılmaz, Erdal Reşit; Özkan, Derya; Arıkök, Ata Türker; Kanat, Mehmet Ali; Şekerci, Zeki

    2015-01-01

    Introduction Spinal anesthesia is a widely used technique of the modern practice of anesthesia. Spinal cord ischemia is a rare but catastrophic complication of spinal anesthesia which may be caused by a direct vasoconstrictive effect of the local anesthetic. Although the vasoconstrictive effects of levobupivacaine have been widely studied, the vasoconstrictive effects of this drug on the intradural arteries have never been studied. The aim of this study is to evaluate whether levobupivacaine has vasoconstrictive effects on the basilar artery in rabbits. Material and methods Thirty male New Zealand white rabbits were divided randomly into three groups of ten rabbits each: group 1 (control); group 2 (0.125% levobupivacaine); group 3 (0.25% levobupivacaine). The cisterna magna was punctured as described below, then 1 ml of saline or 0.125% or 0.25% levobupivacaine was injected into the cisterna magna in 10 min by an infusion pump in groups 1, 2 and 3 respectively. All animals were euthanized by perfusion-fixation 30 min after the procedure. The luminal area and the size of the cross-sectional area for each basilar artery were measured. Results Both 0.125% and 0.25% levobupivacaine infusion caused significant vasoconstriction. Vasoconstriction was more significant for the 0.125% concentration. Conclusions The results of this study indicated that both 0.125% and 0.25% concentrations of levobupivacaine caused significant vasoconstriction of the basilar artery when administered into the subarachnoid space. This may constitute proof that subarachnoid administration of levobupivacaine may diminish the spinal cord blood flow, causing ischemia. PMID:26170861

  17. 10 CFR 500.3 - Electric regions-electric region groupings for reliability measurements under the Powerplant and...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Electric regions-electric region groupings for reliability measurements under the Powerplant and Industrial Fuel Use Act of 1978. 500.3 Section 500.3 Energy DEPARTMENT OF... reliability measurements under the Powerplant and Industrial Fuel Use Act of 1978. (a) The following is a...

  18. 10 CFR 500.3 - Electric regions-electric region groupings for reliability measurements under the Powerplant and...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Electric regions-electric region groupings for reliability measurements under the Powerplant and Industrial Fuel Use Act of 1978. 500.3 Section 500.3 Energy DEPARTMENT OF... reliability measurements under the Powerplant and Industrial Fuel Use Act of 1978. (a) The following is a...

  19. 10 CFR 500.3 - Electric regions-electric region groupings for reliability measurements under the Powerplant and...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Electric regions-electric region groupings for reliability measurements under the Powerplant and Industrial Fuel Use Act of 1978. 500.3 Section 500.3 Energy DEPARTMENT OF... reliability measurements under the Powerplant and Industrial Fuel Use Act of 1978. (a) The following is a...

  20. Changes in Soil Temperature Regimes under Regional Climate Change

    NASA Astrophysics Data System (ADS)

    Millar, S. W.

    2013-12-01

    Soil temperatures can provide a smoothed record of regional changes in atmospheric conditions due to soil thermal properties that reduce the annual air and surface temperature amplitude. In areas with seasonal snow cover, however, its insulating effect isolates the soil thermal regime from winter air temperatures. Under changing regional climate patterns, snow cover extent, depth and duration are decreasing. The net effect is thus an expected winter cooling of soil temperature. However, the extent to which this might be mitigated by warmer summer conditions, and changing soil moisture remains to be seen. To examine the relative strength of a cold-season cooling signal versus enhanced summer warming, a network of soil temperature loggers has recorded hourly soil temperatures over the period 2005-2013 within a single watershed experiencing 'lake effect snow'. Elevations range from 168 m to 612 m, on Silurian and Ordovician shale, limestone, and sandstone that have been heavily glaciated. Most of the sites are located on NY Department of Environmental Conservation land in mixed, hardwood and spruce forests. At six sites in varied topographic and land-use setting, two ONSET HOBO Outdoor 4 channel soil temperature loggers are deployed in order to reduce concerns of data reliability and systematic logger drift. Five sites also record air temperature using HOBO Pro Series Temperature loggers at three sites and HOBO Weather Stations at two. Soil temperature data are recorded at hourly intervals at depths of 2-, 5-, 10-, and 25-cm. Several other sites have been operationalized over the 8 year period, but have been tampered with, damaged, stolen, or have failed. These partial records are included to provide greater geographic representation of changing conditions where possible. Data indicate decreasing winter soil temperatures in specific land-use and topographic settings. Only one site, located in a dense spruce plantation, experiences soil freezing within the top 5 cm

  1. Rho kinase-mediated vasoconstriction in rat models of pulmonary hypertension.

    PubMed

    Oka, Masahiko; Homma, Noriyuki; McMurtry, Ivan F

    2008-01-01

    There is current controversy regarding whether vasoconstriction plays a significant role in the elevated pressure of severe, advanced stages of pulmonary hypertension. Results of acute vasodilator testing using conventional vasodilators in such patients suggest there is only a minor contribution of vasoconstriction. However, there is a possibility that these results may underestimate the contribution of vasoconstriction because the most effective vasodilators have not yet been tested. This issue has not been addressed even experimentally, due mainly to a lack of appropriate animal models. A few animal models that mimic the pathology of human severe pulmonary hypertension more closely (i.e., development of occlusive neointimal lesions in small pulmonary arteries/arterioles) have been introduced, including rat models of left lung pneumonectomy plus monocrotaline injection and vascular endothelial growth factor inhibition plus exposure to chronic hypoxia. We have observed that Rho kinase inhibitors, a novel class of potent vasodilators, reduce the high pulmonary artery pressure of these models acutely and markedly, suggesting that vasoconstriction can significantly be involved in pulmonary hypertension with severely remodeled (occluded) pulmonary vessels. This chapter describes methods used for evaluation of the involvement of Rho kinase-mediated vasoconstriction in rat models of pulmonary hypertension. PMID:18374166

  2. Mechanisms of hypoxic pulmonary vasoconstriction and their roles in pulmonary hypertension: new findings for an old problem

    PubMed Central

    Ward, Jeremy P.T.; McMurtry, Ivan F.

    2009-01-01

    Hypoxic pulmonary vasoconstriction (HPV) normally optimises ventilation-perfusion matching in the lung, but leads to pulmonary hypertension under conditions of global hypoxia. The past few years have provided some major advances in our understanding of this complex phenomenon, but significant controversy remains concerning many of the key underlying mechanisms. On balance, recent evidence is most consistent with an elevation in mitochondria-derived reactive oxygen species as a key event for initiation of HPV, with consequent Ca2+ release from intracellular ryanodine-sensitive stores, although the activation pathways and molecular identity of the associated Ca2+ entry pathways remain unclear. Recent studies have also raised our perception of the critical role played by Rho kinase in both sustained HPV and the development of pulmonary hypertension, further promoting Rho kinase and the pathways regulating its activity and expression as important therapeutic targets. PMID:19297247

  3. Under siege: Isolated tributaries are threatened by regionally impaired metacommunities.

    PubMed

    Merriam, Eric R; Petty, J Todd

    2016-08-01

    Pristine streams are often targeted as conservation priorities because of their ability to preserve regional biodiversity. However, isolation within heavily degraded regions likely alters important metapopulation and metacommunity processes (e.g., rescue and mass effects), affecting the ability of in-tact communities to boost regional conditions. To test this hypothesis, we sampled invertebrate communities and physicochemical conditions from 168 streams within the mountaintop removal-valley fill mining region of West Virginia. We used redundancy analysis to first test for significant effects of local (observed physicochemical conditions) and neighborhood (streams within a 5km buffer) degradation on assemblage structure across all taxa and stress tolerance (low, moderate, high) and dispersal (low, high) categories. We then used generalized linear and hurdle models to characterize changes in community metrics and individual taxa, respectively. Local condition consistently explained the majority of variation (partial R(2) up to 5× those of neighborhood condition) in community structure and was the only factor affecting sensitive taxa. Neighborhood condition explained significant variation in moderately tolerant taxa with low dispersal capacity and highly tolerant taxa, regardless of dispersal. Decreased occurrence (Baetis) and abundance (Maccaffertium) of key taxa and corresponding metrics (%E, %EPT) suggest decreased dispersal and associated mass and rescue effects within degraded neighborhoods. Decreased neighborhood conditions also resulted in the proliferation of tolerant taxa (Chironomidae, Chimarra, Hemerodromia). Our results suggest communities within even the most pristine streams are at risk when isolated within heavily impacted regions. Consequently, protection of regional species' pools in heavily impacted regions will require more than simply conserving un-impacted streams. PMID:27101452

  4. The South Florida Environment: A Region Under Stress

    USGS Publications Warehouse

    McPherson, Benjamin F.; Halley, Robert B.

    1996-01-01

    This report provides an overview of the environmental setting in South Florida and serves as review and framework for developing U.S. Geological Survey programs in the region. The report describes the predevelopment and the current (present-day) environmental conditions in South Florida with emphasis on the quantity and quality of water. The geographical area covered is the southern one-half of the State and includes the South Florida National Water-Quality Assessment study area and adjacent coastal waters. This study area covers about 19,500 square miles and is the watershed of the larger regional ecosystem. The regional ecosystem includes the coastal waters between Charlotte Harbor on the Gulf of Mexico and the St. Lucie River on the Atlantic Ocean and the lands that drain into these waters.

  5. Isolation of zooxanthellatoxins, novel vasoconstrictive substances from the zooxanthella Symbiodinium sp.

    PubMed

    Nakamura, H; Asari, T; Ohizumi, Y; Kobayashi, J; Yamasu, T; Murai, A

    1993-04-01

    Isolation of zooxanthellatoxins, novel vasoconstrictive substances from the zooxanthella Symbiodinium sp. Toxicon 31, 371-376, 1993. New polyhydroxypolyenes with potent vasoconstrictive activity, zooxanthellatoxin-A and -B, were isolated from a symbiotic marine alga Symbiodinium sp. These compounds caused sustained contractions of isolated rabbit aorta at concentrations above 7 x 10(-7) M; this effect was abolished in Ca(2+)-free solution or in the presence of verapamil. Both compounds were relatively large molecules (mol. wt about 2900), containing a large number of oxygen atoms and olefinic carbons, thus differing from two other vasoconstrictive marine toxins, palytoxin and maitotoxin, in containing more olefins than palytoxin, and fewer ethereal rings than maitotoxin. PMID:8503128

  6. The reversible cerebral vasoconstriction syndrome in association with venlafaxine and methenamine.

    PubMed

    Davies, G; Wilson, H; Wilhelm, T; Bowler, J

    2013-01-01

    The reversible cerebral vasoconstriction syndrome (RCVS) is characterised by thunderclap headache and multifocal vasoconstriction of cerebral arteries on angiography. It is often drug induced, but it can occur postpartum, and as a result of a number of other precipitants. To make the diagnosis, it is necessary to exclude other causes of severe headache (such as aneurysmal subarachnoid haemorrhage, carotid dissection and primary angiitis of the central nervous system). However, it is also important to show that the vasoconstriction has resolved with repeat angiography at the 3-month stage. Here we report two cases of RCVS in association with venlafaxine and the urinary antiseptic, methenamine. Serotonin-norepinephrine reuptake inhibitors have recently been reported as a possible precipitant, but this is the first report to implicate methenamine. Although RCVS is relatively uncommon, it should be considered in the differential of those presenting with thunderclap headache. PMID:23771970

  7. Hourly and daily evapotranspiration of alfalfa under regional advection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Regional advection often affects the evapotranspiration rates of irrigated crops in the Southern High Plains. In 1998, during a 10-day period (13-22 June) of unusually strong advection, high evapotranspiration (ET) rates for unstressed, irrigated alfalfa (Medicago sativa) were measured with two prec...

  8. Assessment of Vasoconstrictive Capacity of Tall Fescue Alkaloids Using Fescue Naive Lateral Saphenous Veins of Crossbreed Heifer Cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vasoconstriction is one response associated with consumption of toxic endophyte-infected tall fescue. Because it is not known if endophyte-produced alkaloids act alone or collectively, the objective of this study was to begin to examine the vasoconstrictive potentials of D-lysergic acid (LSA), ergov...

  9. Effects of Selected Combinations of Tall Fescue Alkaloids on the Vasoconstrictive Capacity of Fescue-Naive Bovine Lateral Saphenous Veins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vasoconstriction is a response associated with consumption of toxic endophyte-infected tall fescue. It is not known if endophyte-produced alkaloids act alone or collectively in mediating the response. Therefore, objective of this study was to examine the vasoconstrictive potentials of selected ergot...

  10. Role of thromboxane A₂-activated nonselective cation channels in hypoxic pulmonary vasoconstriction of rat.

    PubMed

    Yoo, Hae Young; Park, Su Jung; Seo, Eun-Young; Park, Kyung Sun; Han, Jung-A; Kim, Kyung Soo; Shin, Dong Hoon; Earm, Yung E; Zhang, Yin-Hua; Kim, Sung Joon

    2012-01-01

    Hypoxia-induced pulmonary vasoconstriction (HPV) is critical for matching of ventilation/perfusion in lungs. Although hypoxic inhibition of K(+) channels has been a leading hypothesis for depolarization of pulmonary arterial smooth muscle cells (PASMCs) under hypoxia, pharmacological inhibition of K(+) channels does not induce significant contraction in rat pulmonary arteries. Because a partial contraction by thromboxane A(2) (TXA(2)) is required for induction of HPV, we hypothesize that TXA(2) receptor (TP) stimulation might activate depolarizing nonselective cation channels (NSCs). Consistently, we found that 5-10 nM U46619, a stable agonist for TP, was indispensible for contraction of rat pulmonary arteries by 4-aminopyridine, a blocker of voltage-gated K(+) channel (K(v)). Whole cell voltage clamp with rat PASMC revealed that U46619 induced a NSC current (I(NSC,TXA2)) with weakly outward rectifying current-voltage relation. I(NSC,TXA2) was blocked by ruthenium red (RR), an antagonist of the transient receptor potential vanilloid-related channel (TRPV) subfamily. 2-Aminoethoxydiphenyl borate, an agonist for TRPV1-3, consistently activated NSC channels in PASMCs. In contrast, agonists for TRPV1 (capsaicin), TRPV3 (camphor), or TRPV4 (α-PDD) rarely induced an increase in the membrane conductance of PASMCs. RT-PCR analysis showed the expression of transcripts for TRPV2 and -4 in rat PASMCs. Finally, it was confirmed that pretreatment with RR largely inhibited HPV in the presence of U46619. The pretreatment with agonists for TRPV1 (capsaicin) and TRPV4 (α-PDD) was ineffective as pretone agents for HPV. Taken together, it is suggested that the concerted effects of I(NSC,TXA2) activation and K(v) inhibition under hypoxia induce membrane depolarization sufficient for HPV. TRPV2 is carefully suggested as the TXA(2)-activated NSC in rat PASMC. PMID:21998141

  11. Contracting human skeletal muscle maintains the ability to blunt α1-adrenergic vasoconstriction during KIR channel and Na+/K+-ATPase inhibition

    PubMed Central

    Crecelius, Anne R; Kirby, Brett S; Hearon, Christopher M; Luckasen, Gary J; Larson, Dennis G; Dinenno, Frank A

    2015-01-01

    Sympathetic vasoconstriction in contracting skeletal muscle is blunted relative to that which occurs in resting tissue; however, the mechanisms underlying this ‘functional sympatholysis’ remain unclear in humans. We tested the hypothesis that α1-adrenergic vasoconstriction is augmented during exercise following inhibition of inwardly rectifying potassium (KIR) channels and Na+/K+-ATPase (BaCl2 + ouabain). In young healthy humans, we measured forearm blood flow (Doppler ultrasound) and calculated forearm vascular conductance (FVC) at rest, during steady-state stimulus conditions (pre-phenylephrine), and after 2 min of phenylephrine (PE; an α1-adrenoceptor agonist) infusion via brachial artery catheter in response to two different stimuli: moderate (15% maximal voluntary contraction) rhythmic handgrip exercise or adenosine infusion. In Protocol 1 (n = 11 subjects) a total of six trials were performed in three conditions: control (saline), combined enzymatic inhibition of nitric oxide (NO) and prostaglandin (PG) synthesis (l-NMMA + ketorolac) and combined inhibition of NO, PGs, KIR channels and Na+/K+-ATPase (l-NMMA + ketorolac + BaCl2 + ouabain). In Protocol 2 (n = 6) a total of four trials were performed in two conditions: control (saline), and combined KIR channel and Na+/K+-ATPase inhibition. All trials occurred after local β-adrenoceptor blockade (propranolol). PE-mediated vasoconstriction was calculated (%ΔFVC) in each condition. Contrary to our hypothesis, despite attenuated exercise hyperaemia of ∼30%, inhibition of KIR channels and Na+/K+-ATPase, combined with inhibition of NO and PGs (Protocol 1) or alone (Protocol 2) did not enhance α1-mediated vasoconstriction during exercise (Protocol 1: −27 ± 3%; P = 0.2 vs. control, P = 0.4 vs.l-NMMA + ketorolac; Protocol 2: −21 ± 7%; P = 0.9 vs. control). Thus, contracting human skeletal muscle maintains the ability to blunt α1-adrenergic vasoconstriction during

  12. Effect of cyclosporin A and analogues on cytosolic calcium and vasoconstriction: possible lack of relationship to immunosuppressive activity.

    PubMed Central

    Lo Russo, A.; Passaquin, A. C.; André, P.; Skutella, M.; Rüegg, U. T.

    1996-01-01

    1. The full therapeutic potential of the main immunosuppressive drug, cyclosporin A (CsA), is limited because of its side effects, namely nephrotoxicity and hypertension. Several lines of evidence suggest that the origin of both side effects could be CsA-induced vasoconstriction. However, the underlying molecular mechanisms are not well understood. 2. Diameter measurements of rat isolated mesenteric arteries showed an increase in noradrenaline- and [Arg]8vasopressin-induced vasoconstriction when arteries were pretreated with CsA. 3. Measurements in cultured vascular smooth muscle cells (VSMC) of either cytosolic calcium concentration or of 45Ca2+ efflux showed that CsA potentiated the calcium influx to several vasoconstrictor hormones: [Arg]8vasopressin, angiotensin II, endothelin-1 and 5-hydroxytryptamine. On the other hand, 45Ca2+ efflux in response to thapsigargin, which depletes calcium from intracellular pools, was not potentiated by CsA. 45Ca2+ uptake was not altered by CsA or by any of the analogues tested. 4. Time-course studies in cultured VSMC showed that maximal CsA-induced Ca2+ potentiation occurred after ca. 20 h and this effect was reversed over approximately the next 20 h. 5. To investigate the possible role played by the known intracellular targets of CsA, namely cyclophilin and calcineurin, CsA derivatives with variable potencies with respect to their immunosuppressive activity, were tested on the calcium influx to [Arg]8vasopressin. Derivatives devoid of immunosuppressive activity (cyclosporin H, PSC-833) potentiated calcium signalling, while the potent immunosuppressant, FK520, a close derivative of FK506, and MeVal4CsA, an antagonist of the immunosuppressive effect of CsA did not. The latter compound was unable to reverse the calcium potentiating effect of CsA. 6. Our results show that CsA increases the calcium influx to vasoconstrictor hormones in smooth muscle cells, which presumably increases vasoconstriction. Loading of the intracellular

  13. Regional feedbacks under changing climate and land-use conditions

    NASA Astrophysics Data System (ADS)

    Batlle Bayer, L.; van den Hurk, B. J. J. M.; Strengers, B. J.; van Minnen, J. G.

    2012-04-01

    Ecosystem responses to a changing climate and human-induced climate forcings (e.g. deforestation) might amplify (positive feedback) or dampen (negative feedback) the initial climate response. Feedbacks may include the biogeochemical (e.g. carbon cycle) and biogeophysical feedbacks (e.g. albedo and hydrological cycle). Here, we first review the most important feedbacks and put them into the context of a conceptual framework, including the major processes and interactions between terrestrial ecosystems and climate. We explore potential regional feedbacks in four hot spots with pronounced potential changes in land-use/management and local climate: sub-Saharan Africa (SSA), Europe, the Amazon Basin and South and Southeast Asia. For each region, the relevant human-induced climate forcings and feedbacks were identified based on published literature. When evapotranspiration is limited by a soil water deficit, heat waves in Europe are amplified (positive soil moisture-temperature feedback). Drought events in the Amazon lead to further rainfall reduction when water recycling processes are affected (positive soil moisture-precipitation feedback). In SSA, the adoption of irrigation in the commonly rainfed systems can modulate the negative soil moisture-temperature feedback. In contrast, future water shortage in South and Southeast Asia can turn the negative soil moisture-temperature feedback into a positive one. Further research including advanced modeling strategies is needed to isolate the dominant processes affecting the strength and sign of the feedbacks. In addition, the socio-economic dimension needs to be considered in the ecosystems-climate system to include the essential role of human decisions on land-use and land-cover change (LULCC). In this context, enhanced integration between Earth System (ES) and Integrated Assessment (IA) modeling communities is strongly recommended.

  14. Vasoconstrictive responses of lambs grazing endophyte-infected perennial ryegrass paddocks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The AR6 novel endophyte (Neotyphodium lolii) produces ergovaline that deters against the African black beetle, but also causes vasoconstriction that restricts an animal’s ability to dissipate body heat. An experiment was conducted with 3, 0.10-ha pastures of ‘Extreme’ perennial ryegrass (Lolium per...

  15. Ergovaline-induced vasoconstriction in an isolated bovine lateral saphenous vein bioassay

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ergovaline has been proposed as a toxic component of endophyte-infected tall fescue. As many of the symptoms of fescue toxicosis are a result of compromised circulation, the objective of this study was to examine the vasoconstrictive potentials of ergovaline and a more documented ergopeptine, ergota...

  16. An Extract of Endophyte Infected Tall Fescue Seed Induces Vasoconstriction of Bovine Foregut Vasculature

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An ethanol extract of tall fescue seed was produced to further understand the interactions of toxic compounds that cause fescue toxicosis. We hypothesized that the combination of alkaloids present in the extract would have a greater vasoconstrictive response than individual alkaloids. The objective ...

  17. Conditioned Eyelid Response, Peripheral Vasoconstriction, and Attention in Retarded and Nonretarded Individuals

    ERIC Educational Resources Information Center

    Mosley, James L.; Bakal, Donald A.

    1974-01-01

    A continuous reinforcement, delayed classical eyelid-conditioning paradigm in combination with the peripheral vasomotor response of digital vasoconstriction was employed to examine the hypothesized attention deficit for 10 15-year-old educable mentally retarded and same-age nonretarded Ss. (Author/MC)

  18. Muscle metaboreflex activation during dynamic exercise vasoconstricts ischemic active skeletal muscle.

    PubMed

    Kaur, Jasdeep; Machado, Tiago M; Alvarez, Alberto; Krishnan, Abhinav C; Hanna, Hanna W; Altamimi, Yasir H; Senador, Danielle; Spranger, Marty D; O'Leary, Donal S

    2015-12-15

    Metabolite accumulation due to ischemia of active skeletal muscle stimulates group III/IV chemosensitive afferents eliciting reflex increases in arterial blood pressure and sympathetic activity, termed the muscle metaboreflex. We and others have previously demonstrated sympathetically mediated vasoconstriction of coronary, renal, and forelimb vasculatures with muscle metaboreflex activation (MMA). Whether MMA elicits vasoconstriction of the ischemic muscle from which it originates is unknown. We hypothesized that the vasodilation in active skeletal muscle with imposed ischemia becomes progressively restrained by the increasing sympathetic vasoconstriction during MMA. We activated the metaboreflex during mild dynamic exercise in chronically instrumented canines via graded reductions in hindlimb blood flow (HLBF) before and after α1-adrenergic blockade [prazosin (50 μg/kg)], β-adrenergic blockade [propranolol (2 mg/kg)], and α1 + β-blockade. Hindlimb resistance was calculated as femoral arterial pressure/HLBF. During mild exercise, HLBF must be reduced below a threshold level before the reflex is activated. With initial reductions in HLBF, vasodilation occurred with the imposed ischemia. Once the muscle metaboreflex was elicited, hindlimb resistance increased. This increase in hindlimb resistance was abolished by α1-adrenergic blockade and exacerbated after β-adrenergic blockade. We conclude that metaboreflex activation during submaximal dynamic exercise causes sympathetically mediated α-adrenergic vasoconstriction in ischemic skeletal muscle. This limits the ability of the reflex to improve blood flow to the muscle. PMID:26475591

  19. Endovascular Electrodes for Electrical Stimulation of Blood Vessels for Vasoconstriction - a Finite Element Simulation Study.

    PubMed

    Kezurer, Noa; Farah, Nairouz; Mandel, Yossi

    2016-01-01

    Hemorrhagic shock accounts for 30-40 percent of trauma mortality, as bleeding may sometimes be hard to control. Application of short electrical pulses on blood vessels was recently shown to elicit robust vasoconstriction and reduction of blood loss following vascular injury. In this study we present a novel approach for vasoconstriction based on endovascular application of electrical pulses for situations where access to the vessel is limited. In addition to ease of access, we hypothesize that this novel approach will result in a localized and efficient vasoconstriction. Using computer modeling (COMSOL Multiphysics, Electric Currents Module), we studied the effect of endovascular pulsed electrical treatment on abdominal aorta of pigs, and compared the efficiency of different electrodes configurations on the electric field amplitude, homogeneity and locality when applied on a blood vessel wall. Results reveal that the optimal configuration is the endovascular approach where four electrodes are used, spaced 13 mm apart. Furthermore, computer based temperature investigations (bio-heat model, COMSOL Multiphysics) show that the maximum expected temperature rise is of 1.2 degrees; highlighting the safety of the four endovascular electrodes configuration. These results can aid in planning the application of endovascular pulsed electrical treatment as an efficient and safe vasoconstriction approach. PMID:27534438

  20. Endovascular Electrodes for Electrical Stimulation of Blood Vessels for Vasoconstriction – a Finite Element Simulation Study

    PubMed Central

    Kezurer, Noa; Farah, Nairouz; Mandel, Yossi

    2016-01-01

    Hemorrhagic shock accounts for 30–40 percent of trauma mortality, as bleeding may sometimes be hard to control. Application of short electrical pulses on blood vessels was recently shown to elicit robust vasoconstriction and reduction of blood loss following vascular injury. In this study we present a novel approach for vasoconstriction based on endovascular application of electrical pulses for situations where access to the vessel is limited. In addition to ease of access, we hypothesize that this novel approach will result in a localized and efficient vasoconstriction. Using computer modeling (COMSOL Multiphysics, Electric Currents Module), we studied the effect of endovascular pulsed electrical treatment on abdominal aorta of pigs, and compared the efficiency of different electrodes configurations on the electric field amplitude, homogeneity and locality when applied on a blood vessel wall. Results reveal that the optimal configuration is the endovascular approach where four electrodes are used, spaced 13 mm apart. Furthermore, computer based temperature investigations (bio-heat model, COMSOL Multiphysics) show that the maximum expected temperature rise is of 1.2 degrees; highlighting the safety of the four endovascular electrodes configuration. These results can aid in planning the application of endovascular pulsed electrical treatment as an efficient and safe vasoconstriction approach. PMID:27534438

  1. Concentrated ambient air particles induce vasoconstriction of small pulmonary arteries in rats.

    PubMed Central

    Batalha, Joao R F; Saldiva, Paulo H N; Clarke, Robert W; Coull, Brent A; Stearns, Rebecca C; Lawrence, Joy; Murthy, G G Krishna; Koutrakis, Petros; Godleski, John J

    2002-01-01

    The objective of this study was to determine whether short-term exposures to concentrated ambient particles (CAPs) alter the morphology of small pulmonary arteries in normal rats and rats with chronic bronchitis (CB). Sprague-Dawley male rats were exposed to CAPs, using the Harvard Ambient Particle Concentrator, or to particle-free air (sham) under identical conditions during 3 consecutive days (5 hr/day) in six experimental sets. CB was induced by exposure to 276 +/- 9 ppm of sulfur dioxide (5 hr/day, 5 days/week, 6 weeks). Physicochemical characterization of CAPs included measurements of particle mass, size distribution, and composition. Rats were sacrificed 24 hr after the last CAPs exposure. Histologic slides were prepared from random sections of lung lobes and coded for blinded analysis. The lumen/wall area (L/W) ratio was determined morphometrically on transverse sections of small pulmonary arteries. When all animal data (normal and CB) were analyzed together, the L/W ratios decreased as concentrations of fine particle mass, silicon, lead, sulfate, elemental carbon, and organic carbon increased. In separate univariate analyses of animal data, the association for sulfate was significant only in normal rats, whereas silicon was significantly associated in both CB and normal rats. In multivariate analyses including all particle factors, the association with silicon remained significant. Our results indicate that short-term CAPs exposures (median, 182.75 micro g/m3; range, 73.50-733.00 micro g/m3) can induce vasoconstriction of small pulmonary arteries in normal and CB rats. This effect was correlated with specific particle components and suggests that the pulmonary vasculature might be an important target for ambient air particle toxicity. PMID:12460797

  2. HIF-2α-mediated induction of pulmonary thrombospondin-1 contributes to hypoxia-driven vascular remodelling and vasoconstriction

    PubMed Central

    Labrousse-Arias, David; Castillo-González, Raquel; Rogers, Natasha M.; Torres-Capelli, Mar; Barreira, Bianca; Aragonés, Julián; Cogolludo, Ángel; Isenberg, Jeffrey S.; Calzada, María J.

    2016-01-01

    Aims Hypoxic conditions stimulate pulmonary vasoconstriction and vascular remodelling, both pathognomonic changes in pulmonary arterial hypertension (PAH). The secreted protein thrombospondin-1 (TSP1) is involved in the maintenance of lung homeostasis. New work identified a role for TSP1 in promoting PAH. Nonetheless, it is largely unknown how hypoxia regulates TSP1 in the lung and whether this contributes to pathological events during PAH. Methods and results In cell and animal experiments, we found that hypoxia induces TSP1 in lungs, pulmonary artery smooth muscle cells and endothelial cells, and pulmonary fibroblasts. Using a murine model of constitutive hypoxia, gene silencing, and luciferase reporter experiments, we found that hypoxia-mediated induction of pulmonary TSP1 is a hypoxia-inducible factor (HIF)-2α-dependent process. Additionally, hypoxic tsp1−/− pulmonary fibroblasts and pulmonary artery smooth muscle cell displayed decreased migration compared with wild-type (WT) cells. Furthermore, hypoxia-mediated induction of TSP1 destabilized endothelial cell–cell interactions. This provides genetic evidence that TSP1 contributes to vascular remodelling during PAH. Expanding cell data to whole tissues, we found that, under hypoxia, pulmonary arteries (PAs) from WT mice had significantly decreased sensitivity to acetylcholine (Ach)-stimulated endothelial-dependent vasodilation. In contrast, hypoxic tsp1−/− PAs retained sensitivity to Ach, mediated in part by TSP1 regulation of pulmonary Kv channels. Translating these preclinical studies, we find in the lungs from individuals with end-stage PAH, both TSP1 and HIF-2α protein expression increased in the pulmonary vasculature compared with non-PAH controls. Conclusions These findings demonstrate that HIF-2α is clearly implicated in the TSP1 pulmonary regulation and provide new insights on its contribution to PAH-driven vascular remodelling and vasoconstriction. PMID:26503986

  3. An experimental investigation of dyke injection under regional extensional stress

    NASA Astrophysics Data System (ADS)

    Daniels, K. A.; Menand, T.

    2015-03-01

    Dyke injection is a fundamental process of magma transport in the crust, occurring in all tectonic settings. The effect of extensional stress regimes on dyke injections is particularly important to understanding a wide spectrum of processes including continental rifting and volcanic activity. Yet dyke injection in extensional regimes has been relatively understudied. In addition, the effect of dyke-dyke interaction modifying the surrounding stress field and leading to dyke rotation about the vertical axis has not been addressed. We present the results from 23 laboratory analogue experiments investigating lateral dyke injections in a remote extensional stress field. This study is unique in that it addresses the effect of both extension and dyke-dyke interaction on the lateral propagation and rotation of dykes. The experiments study the interrelationship between successive lateral dyke injections by examining dyke injection thickness, injection spacing, injection orientation, extension, and structural relationship. A relationship between the rotation angle between two successive intrusions and the distance separating them under given extensional stress conditions is established. The rotation angle depends on two dimensionless numbers: the ratio of fluid overpressure of the first injection and remote tensile stress, and the ratio of the spacing between injections and the height of the first intrusion. The experiments show how the stress field is perturbed by an intrusion and how the remote stress field is locally relieved by this intrusion. The results show furthermore that measuring or estimating the rotation angles between successive intrusions within rift zones allows the spatial distribution of these intrusions to be estimated. In the case of the actively spreading Red Sea rift in Afar, Ethiopia, we find that the vast majority of the dykes are predicted to intrude within 10 km of each other and most frequently between 4 and 5 km, in good agreement with independent

  4. Phenylephrine as an alternative to cocaine for nasal vasoconstriction before nasal surgery: A randomised trial

    PubMed Central

    AlHaddad, Sawsan T; Khanna, Ashish K; Mascha, Edward J; Abdelmalak, Basem B

    2013-01-01

    Background: Cocaine is often used topically to provide the profound vasoconstriction required for nasal surgery; however, it has been associated with intraoperative cardiac adverse effects. We compared cocaine with phenylephrine as an alternative to ascertain their relative efficacy as vasoconstrictors in nasal septoplasty. Methods: Adult patients, presenting for elective nasal septoplasty, of American Society of Anaesthesiologists physical status I-III, were randomised to either 0.5% phenylephrine or 4% cocaine. The primary outcome was quality of vasoconstriction on a 5-point scale (1=unacceptable, 5=excellent), rated by the surgeon at the end of the procedure. Results: Twenty-nine patients received phenylephrine and 26 received cocaine. The median rating for quality of the vasoconstriction was 4.0 (good) in both the phenylephrine and cocaine groups (P=0.84). Median blood loss was 50 ml in the phenylephrine group and 62.5 ml in the cocaine group (P=0.49). In secondary analyses, phenylephrine was shown to be non-inferior to cocaine on both quality of vasoconstriction (non-inferiority delta of 1 point, P=0.009) and estimated blood loss (non-inferiority delta of 25 ml, P=0.028). The frequency of ventricular ectopy, ST segment changes or blood pressure changes after nasal packing was not significantly different between the two groups. Conclusion: Phenylephrine in a concentration of 0.5% is not different from 4% cocaine on the quality of vasoconstriction in septoplasty. Given the abuse potential of cocaine and the added administrative burden associated with its handling, phenylephrine might serve as an alternative. PMID:23825816

  5. Regional Air Quality Under Climate Change Using a Nested Global-Regional Modeling System

    NASA Astrophysics Data System (ADS)

    Dawson, J.; Racherla, P.; Lynn, B.; Adams, P.; Pandis, S.

    2006-12-01

    Strong links between climate, particulate matter and ozone make it likely that climate change will have impacts on air quality. This study examines the effects that climate change will have on concentrations of PM2.5 and ozone in the Eastern US. The changes examined are between the present day and the 2050s. This is accomplished by developing the Global-Regional Climate Air Pollution Modeling System (GRE-CAPS). GRE-CAPS couples a general circulation model (GCM) / global chemical transport model (CTM), a regional meteorological model, and a regional chemical transport model. Present and future climates are simulated by the GISS-II' GCM with an embedded gas-phase and aerosol chemistry model. Meteorology generated by the GCM is downscaled to the regional modeling domain using the MM5 regional climate model. The downscaled meteorology is passed to the regional chemical transport model PMCAMx. In addition to the downscaled meteorology, chemical boundary conditions for the regional model are derived from the global model. The coupled model system is evaluated for the present day by comparing model-predicted concentrations of O3 and PM2.5 to measured concentrations during the last decade. This comparison between typical present- day measurements and model predictions is made for three modeled present-day Julys (both PM2.5 and O3) and three modeled Januaries (PM2.5). Future concentrations (using the IPCC A2 scenario) are compared to present-day concentrations. Concentrations in specific sites and statistical distributions of concentrations will be examined.

  6. Aspirate from human stented saphenous vein grafts induces epicardial coronary vasoconstriction and impairs perfusion and left ventricular function in rat bioassay hearts with pharmacologically induced endothelial dysfunction.

    PubMed

    Lieder, Helmut R; Baars, Theodor; Kahlert, Philipp; Kleinbongard, Petra

    2016-08-01

    Stent implantation into aortocoronary saphenous vein grafts (SVG) releases particulate debris and soluble vasoactive mediators, for example, serotonin. We now analyzed effects of the soluble mediators released into the coronary arterial blood during stent implantation on vasomotion of isolated rat epicardial coronary artery segments and on coronary flow and left ventricular developed pressure in isolated perfused rat hearts. Coronary blood was retrieved during percutaneous SVG intervention using a distal occlusion/aspiration protection device in nine symptomatic patients with stable angina pectoris and a flow-limiting SVG stenosis. The blood was separated into particulate debris and plasma. Responses to coronary plasma were determined in isolated rat epicardial coronary arteries and in isolated, constant pressure-perfused rat hearts (±nitric oxide synthase [NOS] inhibition and ±serotonin receptor blockade, respectively). Coronary aspirate plasma taken after stent implantation induced a stronger vasoconstriction of rat epicardial coronary arteries (52 ± 8% of maximal potassium chloride induced vasoconstriction [% KClmax = 100%]) than plasma taken before stent implantation (12 ± 8% of KClmax); NOS inhibition augmented this vasoconstrictor response (to 110 ± 15% and 24 ± 9% of KClmax). Coronary aspirate plasma taken after stent implantation reduced in isolated perfused rat hearts only under NOS inhibition coronary flow by 17 ± 3% and left ventricular developed pressure by 25 ± 4%. Blockade of serotonin receptors abrogated these effects. Coronary aspirate plasma taken after stent implantation induces vasoconstriction in isolated rat epicardial coronary arteries and reduces coronary flow and left ventricular developed pressure in isolated perfused rat hearts with pharmacologically induced endothelial dysfunction. PMID:27482071

  7. Concurrent activation of multiple vasoactive signaling pathways in vasoconstriction caused by tubuloglomerular feedback: a quantitative assessment.

    PubMed

    Schnermann, Jurgen

    2015-01-01

    Tubuloglomerular feedback (TGF) describes the negative relationship between (a) NaCl concentration at the macula densa and (b) glomerular filtration rate or glomerular capillary pressure. TGF-induced vasoconstriction of the afferent arteriole results from the enhanced effect of several vasoconstrictors with an effect size sequence of adenosine = 20-HETE > angiotensin II > thromboxane = superoxide > renal nerves > ATP. TGF-mediated vasoconstriction is limited by the simultaneous release of several vasodilators with an effect size sequence of nitric oxide > carbon monoxide = kinins > adenosine. The sum of the constrictor effects exceeds that of the dilator effects by the magnitude of the TGF response. The validity of the additive model used in this analysis can be tested by determining the effect of combined inhibition of some or all agents contributing to TGF. Multiple independent contributors to TGF are consistent with the variability of TGF and of the factors contributing to TGF resetting. PMID:25668021

  8. Diflucortolone valerate (Nerisona): a comparative vasoconstriction test in artificially induced hyperemia of the skin.

    PubMed

    Reckers, R; Wendt, H

    1980-01-01

    In 20 healthy volunteers of both sexes the vasoconstrictive activity of diflucortolone valerate in two of its commercially available formulations (water-in-oil emulsion and pure fat base) was compared with that of four other substances: fluocinonide; betamethasone-17,21-dipropionate; hydrocortisone-17-butyrate; and clobetasol-17-propionate in corresponding galenical formulations. The visual assessment of vasoconstrictive activity after 10 hours revealed a statistically significant superiority of diflucortolone valerate in its fat base over the corresponding galenical formulations of fluocinonide, clobetasol-17-propionate, and hydrocortisone-17-butyrate. Diflucortolone valerate in a water-in-oil emulsion was statistically better after eight hours than the cream formulations of fluocinonide; clobetasol-17-propionate, and betamethasone-17,21-dipropionate. PMID:7459929

  9. Vasoconstrictive Responses by the Carotid and Auricular Arteries in goats to Ergot Alkaloid Exposure

    NASA Astrophysics Data System (ADS)

    Aiken, Glen; Flythe, Michael

    2014-11-01

    A fungal endophyte (Neotyphodium coenophialum) infects most plants of ‘Kentucky 31’ tall fescue (Lolium arundinaceum) and produces ergot alkaloids that cause persistent constriction of the vascular system in grazing livestock. Consequently, animals undergoing this toxicosis cannot regulate core body temperature and are vulnerable to heat and cold stresses. An experiment was conducted to determine if the caudal and auricular arteries in goats (Capra aegagrus hircus) vasoconstrict in response to ergot alkaloids. Seven, rumen fistulated goats were fed ad libitum orchardgrass (Dactylis glomeratia) hay and ruminally infused with endophtye-free seed (E-) for a 7-day adjustment period. Two periods followed with E- and endophyte-infected (E+) seed being randomly assigned to the 2 goat groups in period 1 and then switching treatments between groups in period 2. Infused E+ and E- seed were in equal proportions to the hay such that concentrations of ergovaline and ergovalanine were 0.80 µg per g dry matter for the E+ treatment. Cross-sections of both arteries were imaged using Doppler ultrasonography on days 0, 2, 4, 6, 8, and 12 in period 1 and on days 0, 1, 2, 3, 6, 7, and 9 in period 2. Differences from average baseline areas were used to determine presence or absence of alkaloid-induced vasoconstriction. Carotid arteries initiated constriction on imaging day 2 in both periods, and auricular arteries initiated constriction on imaging day 2 in period 1 and on day 6 in period 2. Luminal areas of the carotid arteries in E+ goats were 46% less than baseline areas in both periods after vasoconstriction occurred, whereas auricular arteries in E+ goats were 52% less than baseline areas in period 1 and 38% in period 2. Both arteries in E+ goats in period 1 relaxed relative to baseline areas by imaging day 2 after they were switched to the E- treatment. Results indicated that goats can vasoconstrict when exposed to ergot alkaloids that could disrupt their thermoregulation.

  10. Vasoconstrictive responses by the carotid and auricular arteries in goats to ergot alkaloid exposure1

    PubMed Central

    Aiken, Glen E.; Flythe, Michael D.

    2014-01-01

    A fungal endophyte (Neotyphodium coenophialum) infects most plants of “Kentucky 31” tall fescue (Lolium arundinaceum) and produces ergot alkaloids that cause persistent constriction of the vascular system in grazing livestock. Consequently, animals undergoing this toxicosis cannot regulate core body temperature and are vulnerable to heat and cold stresses. An experiment was conducted to determine if the caudal and auricular arteries in goats (Capra aegagrus hircus) vasoconstrict in response to ergot alkaloids. Seven, rumen fistulated goats were fed ad libitum orchardgrass (Dactylis glomeratia) hay and ruminally infused with endophtye-free seed (E−) for a 7-day adjustment period. Two periods followed with E− and endophyte-infected (E+) seed being randomly assigned to the 2 goat groups in period 1 and then switching treatments between groups in period 2. Infused E+ and E− seed were in equal proportions to the hay such that concentrations of ergovaline and ergovalanine were 0.80 μg per g dry matter for the E+ treatment. Cross-sections of both arteries were imaged using Doppler ultrasonography on days 0, 2, 4, 6, 8, and 12 in period 1 and on days 0, 1, 2, 3, 6, 7, and 9 in period 2. Differences from average baseline areas were used to determine presence or absence of alkaloid-induced vasoconstriction. Carotid arteries initiated constriction on imaging day 2 in both periods, and auricular arteries initiated constriction on imaging day 2 in period 1 and on day 6 in period 2. Luminal areas of the carotid arteries in E+ goats were 46% less than baseline areas in both periods after vasoconstriction occurred, whereas auricular arteries in E+ goats were 52% less than baseline areas in period 1 and 38% in period 2. Both arteries in E+ goats in period 1 relaxed relative to baseline areas by imaging day 2 after they were switched to the E− treatment. Results indicated that goats can vasoconstrict when exposed to ergot alkaloids that could disrupt their

  11. Thromboxane-induced renal vasoconstriction is mediated by the ADP-ribosyl cyclase CD38 and superoxide anion

    PubMed Central

    Vogel, Paul A.; Kopple, Tayler E.; Arendshorst, William J.

    2013-01-01

    The present renal hemodynamic study tested the hypothesis that CD38 and superoxide anion (O2·−) participate in the vasoconstriction produced by activation of thromboxane prostanoid (TP) receptors in the mouse kidney. CD38 is the major mammalian ADP-ribosyl cyclase contributing to vasomotor tone through the generation of cADP-ribose, a second messenger that activates ryanodine receptors to release Ca2+ from the sarcoplasmic reticulum in vascular smooth muscle cells. We evaluated whether the stable thromboxane mimetic U-46619 causes less pronounced renal vasoconstriction in CD38-deficient mice and the involvement of O2·− in U-46619-induced renal vasoconstriction. Our results indicate that U-46619 activation of TP receptors causes renal vasoconstriction in part by activating cADP-ribose signaling in renal resistance arterioles. Based on maximal renal blood flow and renal vascular resistance responses to bolus injections of U-46619, CD38 contributes 30–40% of the TP receptor-induced vasoconstriction. We also found that the antioxidant SOD mimetic tempol attenuated the magnitude of vasoconstriction by U-46619 in both groups of mice, suggesting mediation by O2·−. The degree of tempol blockage of U-46619-induced renal vasoconstriction was greater in wild-type mice, attenuating renal vasoconstriction by 40% compared with 30% in CD38-null mice. In other experiments, U-46619 rapidly stimulated O2·− production (dihydroethidium fluorescence) in isolated mouse afferent arterioles, an effect abolished by tempol. These observations provide the first in vivo demonstration of CD38 and O2·− involvement in the vasoconstrictor effects of TP receptor activation in the kidney and in vitro evidence for TP receptor stimulation of O2·− production by the afferent arteriole. PMID:23884143

  12. In vivo imaging reveals an essential role of vasoconstriction in rupture of the ovarian follicle at ovulation.

    PubMed

    Migone, Fernando F; Cowan, Robert G; Williams, Rebecca M; Gorse, Kiersten J; Zipfel, Warren R; Quirk, Susan M

    2016-02-23

    Rupture of the ovarian follicle releases the oocyte at ovulation, a timed event that is critical for fertilization. It is not understood how the protease activity required for rupture is directed with precise timing and localization to the outer surface, or apex, of the follicle. We hypothesized that vasoconstriction at the apex is essential for rupture. The diameter and blood flow of individual vessels and the thickness of the apical follicle wall were examined over time to expected ovulation using intravital multiphoton microscopy. Vasoconstriction of apical vessels occurred within hours preceding follicle rupture in wild-type mice, but vasoconstriction and rupture were absent in Amhr2(cre/+)SmoM2 mice in which follicle vessels lack the normal association with vascular smooth muscle. Vasoconstriction is not simply a response to reduced thickness of the follicle wall; vasoconstriction persisted in wild-type mice when thinning of the follicle wall was prevented by infusion of protease inhibitors into the ovarian bursa. Ovulation was inhibited by preventing the periovulatory rise in the expression of the vasoconstrictor endothelin 2 by follicle cells of wild-type mice. In these mice, infusion of vasoconstrictors (either endothelin 2 or angiotensin 2) into the bursa restored the vasoconstriction of apical vessels and ovulation. Additionally, infusion of endothelin receptor antagonists into the bursa of wild-type mice prevented vasoconstriction and follicle rupture. Processing tissue to allow imaging at increased depth through the follicle and transabdominal ultrasonography in vivo showed that decreased blood flow is restricted to the apex. These results demonstrate that vasoconstriction at the apex of the follicle is essential for ovulation. PMID:26842836

  13. Stereoselective inhibition of thromboxane-induced coronary vasoconstriction by 1,4-dihydropyridine calcium channel antagonists

    SciTech Connect

    Eltze, M.; Boer, R.; Sanders, K.H.; Boss, H.; Ulrich, W.R.; Flockerzi, D. )

    1990-01-01

    The biological activity of the (+)-S- and (-)-R-enantiomers of niguldipine, of the (-)-S- and (+)-R-enantiomers of felodipine and nitrendipine, and of rac-nisoldipine and rac-nimodipine was investigated in vitro and in vivo. Inhibition of coronary vasoconstriction due to the thromboxane A2 (TxA2)-mimetic U-46619 in guinea pig Langendorff hearts, displacement of (+)-({sup 3}H)isradipine from calcium channel binding sites of guinea pig skeletal muscle T-tubule membranes, and blood pressure reduction in spontaneously hypertensive rats were determined. The enantiomers were obtained by stereoselective synthesis. Cross-contamination was less than 0.5% for both S- and R-enantiomers of niguldipine and nitrendipine and less than 1% for those of felodipine. From the doses necessary for a 50% inhibition of coronary vasoconstriction, stereoselectivity ratios for (+)-(S)-/(-)-(R)-niguldipine, (-)-(S)-/(+)-(R)-felodipine, and (-)-(S)-/(+)-(R)-nitrendipine of 28, 13, and 7, respectively, were calculated. The potency ratio rac-nisoldipine/rac-nimodipine was 3.5. Ratios obtained from binding experiments and antihypertensive activity were (+)-(S)-/(-)-(R)-niguldipine = 45 and 35, (-)-(S)-/(+)-(R)-felodipine = 12 and 13, (-)-(S)-/(+)-(R)-nitrendipine = 8 and 8, and rac-nisoldipine/rac-nimodipine = 8 and 7, respectively. Highly significant correlations were found between the in vitro potency of the substances to prevent U-46619-induced coronary vasoconstriction and their affinity for calcium channel binding sites as well as their antihypertensive activity.

  14. Endosomolytic Nano-Polyplex Platform Technology for Cytosolic Peptide Delivery To Inhibit Pathological Vasoconstriction

    PubMed Central

    2016-01-01

    A platform technology has been developed and tested for delivery of intracellular-acting peptides through electrostatically complexed nanoparticles, or nano-polyplexes, formulated from an anionic endosomolytic polymer and cationic therapeutic peptides. This delivery platform has been initially tested and optimized for delivery of two unique vasoactive peptides, a phosphomimetic of heat shock protein 20 and an inhibitor of MAPKAP kinase II, to prevent pathological vasoconstriction (i.e., vasospasm) in human vascular tissue. These peptides inhibit vasoconstriction and promote vasorelaxation by modulating actin dynamics in vascular smooth muscle cells. Formulating these peptides into nano-polyplexes significantly enhances peptide uptake and retention, facilitates cytosolic delivery through a pH-dependent endosomal escape mechanism, and enhances peptide bioactivity in vitro as measured by inhibition of F-actin stress fiber formation. In comparison to treatment with the free peptides, which were endowed with cell-penetrating sequences, the nano-polyplexes significantly increased vasorelaxation, inhibited vasoconstriction, and decreased F-actin formation in the human saphenous vein ex vivo. These results suggest that these formulations have significant potential for treatment of conditions such as cerebral vasospasm following subarachnoid hemorrhage. Furthermore, because many therapeutic peptides include cationic cell-penetrating segments, this simple and modular platform technology may have broad applicability as a cost-effective approach for enhancing the efficacy of cytosolically active peptides. PMID:26004140

  15. Nitric oxide mediates the inhibitory action of platelet-activating factor on angiotensin II-induced renal vasoconstriction, in vivo.

    PubMed

    Handa, R K; Strandhoy, J W

    1996-06-01

    The objective of our study was to determine the mechanism(s) involved in the inhibitory effect of platelet-activating factor on renal vascular reactivity, in vivo. Bolus injections of vasoconstrictor agonists were administered into the renal circulation of pentobarbital anesthetized male Wistar rats at a dose to cause a transient 45 to 50% decrease in renal blood flow. Intrarenal infusion of platelet-activating factor (PAF) at 2.5 ng/min/kg attenuated the vasoconstrictor response to angiotensin II by 66%, a significantly smaller reduction of 35% for norepinephrine-mediated vasoconstriction, 22% for vasopressin-mediated vasoconstriction and no alteration of KCl-mediated vasoconstriction. The preferential inhibitory effect of platelet-activating factor on angiotensin II-mediated renal vasoconstriction was mimicked by the intrarenal infusion of either 0.2 to 5 micrograms/min/kg methacholine (endothelium-dependent vasodilator) or 2 micrograms/min/kg sodium nitroprusside (nitric oxide donor). After inhibition of nitric oxide synthesis with NG-monomethyl-L-arginine, intrarenal infusion of PAF or methacholine reduced angiotensin II-mediated renal vasoconstriction significantly less than that observed in the absence of NG-monomethyl-L-arginine. Therefore, this study provides evidence that the shared ability of platelet-activating factor and methacholine to selectively reduce angiotensin II-mediated renal vasoconstriction involves endothelium-derived nitric oxide. PMID:8667214

  16. Mitigation of Ergot Vasoconstriction by Clover Isoflavones in Goats (Capra hircus)

    PubMed Central

    Aiken, Glen E.; Flythe, Michael D.; Kagan, Isabelle A.; Ji, Huihua; Bush, Lowell P.

    2016-01-01

    Ergot alkaloids produced by a fungal endophyte (Epichloë coenophiala; formerly Neotyphodium coenophialum) that infects tall fescue (Lolium arundinaceum) can induce persistent constriction of the vasculature in ruminants, hindering their capability to thermo-regulate core body temperature. There is evidence that isoflavones produced by legumes can relax the vasculature, which suggests that they could relieve ergot alkaloid-induced vasoconstriction and mitigate the vulnerability to severe heat stress in ruminants that graze tall fescue. To test if isoflavones can relieve alkaloid-induced vasoconstriction, two pen experiments were conducted with rumen-fistulated goats (Capra hircus) to determine with ultrasonograpy if isoflavones can (1) promote vascular compliance by countering alkaloid-induced vasoconstriction and (2) relieve already imposed alkaloid-induced vasoconstriction. Goats were fed ad libitum chopped orchardgrass (Dactylis glomerata)–timothy (Phleum pratense) hay prior to conducting the experiments. Measures of carotid and interosseous luminal areas were obtained pre- (baseline) and post-ruminal infusions in both experiments with goats being fed the hay, and for blood flow rate in the carotid artery in Experiment 2. Responses to infusion treatments were evaluated as proportionate differences from baseline measures. Peak systolic velocity, pulsatility index, and heart rate were measured on the last day on treatment (DOT) in Experiment 1, and on all imaging sessions during Experiment 2. For Experiment 1, rumens were infused with ground toxic fescue seed and isoflavones in Phase A and with only the toxic seed in Phase B. The infusion treatments were switched between phases in Experiment 2, which employed a fescue seed extract having an ergot alkaloid composition equivalent to that of the ground seed used in Experiment 1. During Experiment 1, luminal areas of carotid and interosseous arteries in Phase A did not deviate (P > 0.1) from baselines over 1, 2

  17. Mitigation of Ergot Vasoconstriction by Clover Isoflavones in Goats (Capra hircus).

    PubMed

    Aiken, Glen E; Flythe, Michael D; Kagan, Isabelle A; Ji, Huihua; Bush, Lowell P

    2016-01-01

    Ergot alkaloids produced by a fungal endophyte (Epichloë coenophiala; formerly Neotyphodium coenophialum) that infects tall fescue (Lolium arundinaceum) can induce persistent constriction of the vasculature in ruminants, hindering their capability to thermo-regulate core body temperature. There is evidence that isoflavones produced by legumes can relax the vasculature, which suggests that they could relieve ergot alkaloid-induced vasoconstriction and mitigate the vulnerability to severe heat stress in ruminants that graze tall fescue. To test if isoflavones can relieve alkaloid-induced vasoconstriction, two pen experiments were conducted with rumen-fistulated goats (Capra hircus) to determine with ultrasonograpy if isoflavones can (1) promote vascular compliance by countering alkaloid-induced vasoconstriction and (2) relieve already imposed alkaloid-induced vasoconstriction. Goats were fed ad libitum chopped orchardgrass (Dactylis glomerata)-timothy (Phleum pratense) hay prior to conducting the experiments. Measures of carotid and interosseous luminal areas were obtained pre- (baseline) and post-ruminal infusions in both experiments with goats being fed the hay, and for blood flow rate in the carotid artery in Experiment 2. Responses to infusion treatments were evaluated as proportionate differences from baseline measures. Peak systolic velocity, pulsatility index, and heart rate were measured on the last day on treatment (DOT) in Experiment 1, and on all imaging sessions during Experiment 2. For Experiment 1, rumens were infused with ground toxic fescue seed and isoflavones in Phase A and with only the toxic seed in Phase B. The infusion treatments were switched between phases in Experiment 2, which employed a fescue seed extract having an ergot alkaloid composition equivalent to that of the ground seed used in Experiment 1. During Experiment 1, luminal areas of carotid and interosseous arteries in Phase A did not deviate (P > 0.1) from baselines over 1, 2, 3

  18. Gq-coupled receptors as mechanosensors mediating myogenic vasoconstriction

    PubMed Central

    y Schnitzler, Michael Mederos; Storch, Ursula; Meibers, Simone; Nurwakagari, Pascal; Breit, Andreas; Essin, Kirill; Gollasch, Maik; Gudermann, Thomas

    2008-01-01

    Despite the central physiological function of the myogenic response, the underlying signalling pathways and the identity of mechanosensors in vascular smooth muscle (VSM) are still elusive. In contrast to present thinking, we show that membrane stretch does not primarily gate mechanosensitive transient receptor potential (TRP) ion channels, but leads to agonist-independent activation of Gq/11-coupled receptors, which subsequently signal to TRPC channels in a G protein- and phospholipase C-dependent manner. Mechanically activated receptors adopt an active conformation, allowing for productive G protein coupling and recruitment of β-arrestin. Agonist-independent receptor activation by mechanical stimuli is blocked by specific antagonists and inverse agonists. Increasing the AT1 angiotensin II receptor density in mechanically unresponsive rat aortic A7r5 cells resulted in mechanosensitivity. Myogenic tone of cerebral and renal arteries is profoundly diminished by the inverse angiotensin II AT1 receptor agonist losartan independently of angiotensin II (AII) secretion. This inhibitory effect is enhanced in blood vessels of mice deficient in the regulator of G-protein signalling-2. These findings suggest that Gq/11-coupled receptors function as sensors of membrane stretch in VSM cells. PMID:18987636

  19. Postural hypocapnic hyperventilation is associated with enhanced peripheral vasoconstriction in postural tachycardia syndrome with normal supine blood flow.

    PubMed

    Stewart, Julian M; Medow, Marvin S; Cherniack, Neil S; Natelson, Benjamin H

    2006-08-01

    Previous investigations have demonstrated a subset of postural tachycardia syndrome (POTS) patients characterized by normal peripheral resistance and blood volume while supine but thoracic hypovolemia and splanchnic blood pooling while upright secondary to splanchnic hyperemia. Such "normal-flow" POTS patients often demonstrate hypocapnia during orthostatic stress. We studied 20 POTS patients (14-23 yr of age) and compared them with 10 comparably aged healthy volunteers. We measured changes in heart rate, blood pressure, heart rate and blood pressure variability, arm and leg strain-gauge occlusion plethysmography, respiratory impedance plethysmography calibrated against pneumotachography, end-tidal partial pressure of carbon dioxide (Pet(CO2)), and impedance plethysmographic indexes of blood volume and blood flow within the thoracic, splanchnic, pelvic (upper leg), and lower leg regional circulations while supine and during upright tilt to 70 degrees. Ten POTS patients demonstrated significant hyperventilation and hypocapnia (POTS(HC)) while 10 were normocapnic with minimal increase in postural ventilation, comparable to control. While relative splanchnic hypervolemia and hyperemia occurred in both POTS groups compared with controls, marked enhancement in peripheral vasoconstriction occurred only in POTS(HC) and was related to thoracic blood flow. Variability indexes suggested enhanced sympathetic activation in POTS(HC) compared with other subjects. The data suggest enhanced cardiac and peripheral sympathetic excitation in POTS(HC). PMID:16565300

  20. Exercise training and α1-adrenoreceptor-mediated sympathetic vasoconstriction in resting and contracting skeletal muscle.

    PubMed

    Just, Timothy P; DeLorey, Darren S

    2016-02-01

    Exercise training (ET) increases sympathetic vasoconstrictor responsiveness and enhances contraction-mediated inhibition of sympathetic vasoconstriction (i.e., sympatholysis) through a nitric oxide (NO)-dependent mechanism. Changes in α2-adrenoreceptor vasoconstriction mediate a portion of these training adaptations, however the contribution of other postsynaptic receptors remains to be determined. Therefore, the purpose of this study was to investigate the effect of ET on α1-adrenoreceptor-mediated vasoconstriction in resting and contracting muscle. It was hypothesized that α1-adrenoreceptor-mediated sympatholysis would be enhanced following ET. Male Sprague Dawley rats were randomized to sedentary (S; n = 12) or heavy-intensity treadmill ET (n = 11) groups. Subsequently, rats were anesthetized and instrumented for lumbar sympathetic chain stimulation and measurement of femoral vascular conductance (FVC) at rest and during muscle contraction. The percentage change in FVC in response to sympathetic stimulation was measured in control, α1-adrenoreceptor blockade (Prazosin; 20 μg, IV), and combined α1 and NO synthase (NOS) blockade (l-NAME; 5 mg·kg(-1) IV) conditions. Sympathetic vasoconstrictor responsiveness was increased (P < 0.05) in ET compared to S rats at low, but not high (P > 0.05) stimulation frequencies at rest (S: 2 Hz: -25 ± 4%; 5 Hz: -45 ± 5 %; ET: 2 Hz: -35 ± 7%, 5 Hz: -52 ± 7%), whereas sympathetic vasoconstrictor responsiveness was not different (P > 0.05) between groups during contraction (S: 2 Hz: -11 ± 8%; 5 Hz: -26 ± 11%; ET: 2 Hz: -10 ± 7%, 5 Hz: -27 ± 12%). Prazosin blunted (P < 0.05) vasoconstrictor responsiveness in S and ET rats at rest and during contraction, and abolished group differences in vasoconstrictor responsiveness. Subsequent NOS blockade increased vasoconstrictor responses (P < 0.05) in S at rest and during contraction, whereas in ET vasoconstriction was increased (P < 0

  1. The role of classical transient receptor potential channels in the regulation of hypoxic pulmonary vasoconstriction.

    PubMed

    Fuchs, B; Dietrich, A; Gudermann, T; Kalwa, H; Grimminger, F; Weissmann, N

    2010-01-01

    Hypoxic pulmonary vasoconstriction (HPV) is an essential mechanism of the lung matching blood perfusion to ventilation during local alveolar hypoxia. HPV thus optimizes pulmonary gas exchange. In contrast chronic and generalized hypoxia leads to pulmonary vascular remodeling with subsequent pulmonary hypertension and right heart hypertrophy. Among other non-selective cation channels, the family of classical transient receptor potential channels (TRPC) has been shown to be expressed in pulmonary arterial smooth muscle cells. Among this family, TRPC6 is essential for the regulation of acute HPV in mice. Against this background, in this chapter we give an overview about the TRPC family and their role in HPV. PMID:20204731

  2. Sustained cutaneous vasoconstriction during and following cyrotherapy treatment: Role of oxidative stress and Rho kinase.

    PubMed

    Christmas, Kevin M; Patik, Jordan C; Khoshnevis, Sepideh; Diller, Kenneth R; Brothers, R Matthew

    2016-07-01

    Cryotherapy is a therapeutic technique using ice or cold water applied to the skin to reduce bleeding, inflammation, pain, and swelling following soft tissue trauma and injury. While beneficial, there are some side effects such as pronounced vasoconstriction and tissue ischemia that are sustained for hours post-treatment. This study tested the hypothesis that this vasoconstriction is mediated by 1) the Rho-kinase pathway and/or 2) elevated oxidative stress. 9 subjects were fitted with a commercially available cryotherapy unit with a water perfused bladder on the lateral portion of the right calf. Participants were instrumented with three microdialysis probes underneath the bladder. One site received lactated ringers (control site), one received the Rho-Kinase inhibitor Fasudil, and one received Ascorbic Acid. Skin temperature (Tskin) and cutaneous vascular conductance (CVC) was measured at each site. Subjects had 1°C water perfused through the bladder for 30min, followed by passive rewarming for 90min. Tskin fell from ~34°C to ~18.0°C during active cooling across all sites and this response was similar for all sites (P>0.05 for all comparisons). During passive rewarming Tskin rose to a similar degree in all sites (P>0.05 relative to the end of cooling). %CVC was reduced during active cooling in all sites; however, the magnitude of this response was blunted in the Fasudil site relative to control (P<0.001 for all comparisons) and min 25 and 30 of cooling in the Ascorbic Acid site (P<0.05). During passive rewarming %CVC at the control and Ascorbic Acid sites did not change such that values were similar to the end of cooling (P>0.05 for each comparison). %CVC at the Fasudil site remained elevated during passive rewarming such that values were higher compared to the control and Ascorbic Acid sites throughout the 90min of passive rewarming (P<0.001 main effect of Fasudil). These findings indicate that the Rho-kinase pathway contributes to pronounced vasoconstriction

  3. TNF potentiates PAF-induced pulmonary vasoconstriction in the rat: role of neutrophils and thromboxane A2.

    PubMed

    Chang, S W

    1994-12-01

    Both tumor necrosis factor (TNF) and platelet-activating factor (PAF) are released during sepsis and are important mediators of septic lung injury. I investigated the interactions of TNF and PAF on vasoactive responses in the pulmonary circulation. In isolated rat lungs perfused with a cell- and plasma-free physiological salt solution, PAF (0.01- and 0.1-micrograms boluses) caused transient dose-dependent pulmonary arterial and venous constrictions. In vivo pretreatment of the rats with TNF (0.02 or 0.2 mg/kg i.v.) 1 h before lung isolation increased lung myeloperoxidase activity and markedly enhanced PAF-induced pulmonary vasoconstriction without affecting the pressor responses to angiotensin II or hypoxia. In contrast, pretreatment with lipopolysaccharide (10 mg/kg), which increased lung myeloperoxidase to the same extent as TNF, caused only a modest enhancement of PAF-induced vasoconstriction associated with reduced pressor responses to angiotensin II and hypoxia. Ex vivo perfusion of isolated lungs with TNF for 1 h did not affect PAF vasoconstriction. The TNF-induced potentiation of PAF vasoconstriction was not altered by depletion of circulating neutrophils with vinblastine but was blocked by Dazmegrel, a thromboxane synthase inhibitor. Thus, TNF potentiates PAF-induced pulmonary vasoconstriction by an in vivo mechanism that is neutrophil independent but thromboxane dependent. This TNF-PAF interaction likely contributes to the development of pulmonary hypertension during sepsis. PMID:7896627

  4. 20 CFR 661.290 - Under what circumstances may States require Local Boards to take part in regional planning...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) The State may require Local Boards within a designated region (as defined at 20 CFR 660.300) to: (1) Participate in a regional planning process that results in regional performance measures for workforce investment activities under title I of WIA. Regions that meet or exceed the regional performance measures...

  5. Soil N cycling and phenols accumulation under continuous rice cropping in the Grand Prairie region, Arkansas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil C stocks in the Grand Prairie region of eastern Arkansas have declined under the prevalent two-year rotation of rice (Orzya sativa L.) soybean (Glycine max (L.) Merr.). Continuous rice cropping could promote soil C sequestration, but in previous work continuous rice averaged 19% less grain yiel...

  6. Glucose metabolism in different regions of the rat brain under hypokinetic stress influence

    NASA Technical Reports Server (NTRS)

    Konitzer, K.; Voigt, S.

    1980-01-01

    Glucose metabolism in rats kept under long term hypokinetic stress was studied in 7 brain regions. Determination was made of the regional levels of glucose, lactate, glutamate, glutamine, aspartate, gamma-aminobutyrate and the incorporation of C-14 from plasma glucose into these metabolites, in glycogen and protein. From the content and activity data the regional glucose flux was approximated quantitatively. Under normal conditions the activity gradient cortex and frontal pole cerebellum, thalamus and mesencephalon, hypothalamus and pons and medulla is identical with that of the regional blood supply (measured with I131 serum albumin as the blood marker). Within the first days of immobilization a functional hypoxia occurred in all brain regions and the utilization of cycle amino acids for protein synthesis was strongly diminished. After the first week of stress the capillary volumes of all regions increased, aerobic glucose metabolism was enhanced (factors 1.3 - 2.0) and the incorporation of glucose C-14 via cycle amino acids into protein was considerably potentiated. The metabolic parameters normalized between the 7th and 11th week of stress. Blood supply and metabolic rate increased most in the hypothalamus.

  7. Hypoxic pulmonary vasoconstriction in the absence of pretone: essential role for intracellular Ca2+ release

    PubMed Central

    Connolly, Michelle J; Prieto-Lloret, Jesus; Becker, Silke; Ward, Jeremy P T; Aaronson, Philip I

    2013-01-01

    Hypoxic pulmonary vasoconstriction (HPV) maintains blood oxygenation during acute hypoxia but contributes to pulmonary hypertension during chronic hypoxia. The mechanisms of HPV remain controversial, in part because HPV is usually studied in the presence of agonist-induced preconstriction (‘pretone’). This potentiates HPV but may obscure and distort its underlying mechanisms. We therefore carried out an extensive assessment of proposed mechanisms contributing to HPV in isolated intrapulmonary arteries (IPAs) in the absence of pretone by using a conventional small vessel myograph. Hypoxia elicited a biphasic constriction consisting of a small transient (phase 1) superimposed upon a sustained (phase 2) component. Neither phase was affected by the L-type Ca2+ channel antagonists diltiazem (10 and 30 μm) or nifedipine (3 μm). Application of the store-operated Ca2+ entry (SOCE) blockers BTP2 (10 μm) or SKF96365 (50 μm) attenuated phase 2 but not phase 1, whereas a lengthy (30 min) incubation in Ca2+-free physiological saline solution similarly reduced phase 2 but abolished phase 1. No further effect of inhibition of HPV was observed if the sarco/endoplasmic reticulum Ca2+-ATPase inhibitor cyclopiazonic acid (30 μm) was also applied during the 30 min incubation in Ca2+-free physiological saline solution. Pretreatment with 10 μm ryanodine and 15 mm caffeine abolished both phases, whereas treatment with 100 μm ryanodine attenuated both phases. The two-pore channel blocker NED-19 (1 μm) and the nicotinic acid adenine dinucleotide phosphate (NAADP) antagonist BZ194 (200 μm) had no effect on either phase of HPV. The lysosomal Ca2+-depleting agent concanamycin (1 μm) enhanced HPV if applied during hypoxia, but had no effect on HPV during a subsequent hypoxic challenge. The cyclic ADP ribose antagonist 8-bromo-cyclic ADP ribose (30 μm) had no effect on either phase of HPV. Neither the Ca2+-sensing receptor (CaSR) blocker NPS2390 (0.1 and 10 μm) nor FK506 (10

  8. Mechanisms and modifiers of reflex induced cutaneous vasodilation and vasoconstriction in humans

    PubMed Central

    2010-01-01

    Human skin blood flow responses to body heating and cooling are essential to the normal processes of physiological thermoregulation. Large increases in skin blood flow provide the necessary augmentation of convective heat loss during environmental heat exposure and/or exercise, just as reflex cutaneous vasoconstriction is key to preventing excessive heat dissipation during cold exposure. In humans, reflex sympathetic innervation of the cutaneous circulation has two branches: a sympathetic noradrenergic vasoconstrictor system, and a non-noradrenergic active vasodilator system. Noradrenergic vasoconstrictor nerves are tonically active in normothermic environments and increase their activity during cold exposure, releasing both norepinephrine and cotransmitters (including neuropeptide Y) to decrease skin blood flow. The active vasodilator system in human skin does not exhibit resting tone and is only activated during increases in body temperature, such as those brought about by heat exposure or exercise. Active cutaneous vasodilation occurs via cholinergic nerve cotransmission and has been shown to include potential roles for nitric oxide, vasoactive intestinal peptide, prostaglandins, and substance P (and/or neurokinin-1 receptors). It has proven both interesting and challenging that no one substance has been identified as the sole mediator of active cutaneous vasodilation. The processes of reflex cutaneous vasodilation and vasoconstriction are both modified by acute factors, such as exercise and hydration, and more long-term factors, such as aging, reproductive hormones, and disease. This review will highlight some of the recent findings in these areas, as well as interesting areas of ongoing and future work. PMID:20448028

  9. Sympathetic nerve stimulation induces local endothelial Ca2+ signals to oppose vasoconstriction of mouse mesenteric arteries

    PubMed Central

    Nausch, Lydia W. M.; Bonev, Adrian D.; Heppner, Thomas J.; Tallini, Yvonne; Kotlikoff, Michael I.

    2012-01-01

    It is generally accepted that the endothelium regulates vascular tone independent of the activity of the sympathetic nervous system. Here, we tested the hypothesis that the activation of sympathetic nerves engages the endothelium to oppose vasoconstriction. Local inositol 1,4,5-trisphosphate (IP3)-mediated Ca2+ signals (“pulsars”) in or near endothelial projections to vascular smooth muscle (VSM) were measured in an en face mouse mesenteric artery preparation. Electrical field stimulation of sympathetic nerves induced an increase in endothelial cell (EC) Ca2+ pulsars, recruiting new pulsar sites without affecting activity at existing sites. This increase in Ca2+ pulsars was blocked by bath application of the α-adrenergic receptor antagonist prazosin or by TTX but was unaffected by directly picospritzing the α-adrenergic receptor agonist phenylephrine onto the vascular endothelium, indicating that nerve-derived norepinephrine acted through α-adrenergic receptors on smooth muscle cells. Moreover, EC Ca2+ signaling was not blocked by inhibitors of purinergic receptors, ryanodine receptors, or voltage-dependent Ca2+ channels, suggesting a role for IP3, rather than Ca2+, in VSM-to-endothelium communication. Block of intermediate-conductance Ca2+-sensitive K+ channels, which have been shown to colocalize with IP3 receptors in endothelial projections to VSM, enhanced nerve-evoked constriction. Collectively, our results support the concept of a transcellular negative feedback module whereby sympathetic nerve stimulation elevates EC Ca2+ signals to oppose vasoconstriction. PMID:22140050

  10. Bone scintigraphy in acute renal failure with severe loin pain and patchy renal vasoconstriction.

    PubMed

    Han, J S; Kim, Y G; Kim, S; Lee, M C; Lee, J S; Kim, S H

    1991-01-01

    To evaluate the patterns of renal images and the diagnostic value as a screening test of the whole-body bone and renal scintigraphy with technetium-99m-methylene diphosphonate (99mTc-MDP) or -pyrophosphate (99mTc-PYP), we performed bone scintigraphy in 6 patients with acute renal failure (ARF) with severe loin pain and patchy renal vasoconstriction on postcontrast renal computed tomography (CT). All 6 patients were young and previously healthy but experienced severe loin pain after track events. Five took analgesics. Postcontrast renal CT showed patchy low-density areas or diffuse enhancement immediately after radiocontrast injection and then patchy wedge-shaped enhancement 24 or 48 h later, which subsequently disappeared 72 h later. On the whole-body bone scintigrams with 99mTc-MDP or 99mTc-PYP before obtaining renal CT, there was no increased uptake of isotope in the soft tissue, and multiple patchy increased accumulations of the isotope in the kidney were observed in 5 patients. In 2 patients, renal scintigraphies with technetium-99m-dimercaptosuccinate showed photon-deficient areas in the same areas of patchy isotope accumulation in the whole-body bone scintigraphies. Whole-body image and renal scintigraphy with bone-seeking agents may be useful as a screening test and in the search for the theoretical evidence of ARF with severe loin pain and patchy renal vasoconstriction. PMID:1835520

  11. [Vasoconstriction is required for edema of contralateral lung after reperfusion injury of one lung].

    PubMed

    Pezzulo, Alejandro; Castro, Ignacio; Trejo, Humberto; Urich, Daniela; Caraballo, Juan; Gutiérrez, Jeydith; Cano, Camilo; Sánchez de León, Roberto

    2010-03-01

    Ischemia-reperfusion (IR) lung injury is a significant cause of morbidity and mortality in certain clinical scenarios that include transplantation, thromboendarterectomy and reexpansion injury of the lung. Edema of the contralateral lung after IR injury of one lung has been reported and this study was aimed to clarify the pathophysiology of this phenomenon. One-lung ischemia/hypoxia followed by reperfusion with either blood or an acellular plasma substitute was achieved in an isolated rabbit lung model by hilum clamping. After reperfusion, we studied the isolated effects of vasoconstriction and inflammation on contralateral lung injury by using papaverine or hydrocortisone as vasodilator and anti-inflammatory, respectively. We observed that IR of one lung induces edema of the contralateral lung. Absence of leukocytes and platelets in the perfusate or use of hydrocortisone completely inhibits IR injury. Moreover, papaverine suppresses edema of the contralateral, but not that of the reperfused lung. We concluded that IR of one lung produces edema in the contralateral lung that requires vasoconstriction of the latter. PMID:20815156

  12. Alcohol lowers the vasoconstriction threshold in humans without affecting core cooling rate during mild cold exposure.

    PubMed

    Johnston, C E; Bristow, G K; Elias, D A; Giesbrecht, G G

    1996-01-01

    Elevated blood alcohol levels are often seen in hypothermia and hyperthermia related deaths, leading to the belief that alcohol renders humans poikilothermic. We examined the core temperature (Tco) thresholds for sweating, vasoconstriction and shivering as well as core cooling rates of seven subjects immersed in 28 degrees C water. On two separate days, subjects exercised on an underwater cycle ergometer to elevate Tco above the sweating threshold. They then rested and cooled until they shivered vigorously. Subjects drank orange juice (7 ml.kg-1) prior to immersion during the control trial and 1 ml.kg-1 absolute ethanol, added to orange juice in a 1:6 ratio, during the alcohol trial. Mean blood alcohol concentration (breath analysis) was 0.097 +/- 0.010 g% at the start of cooling and 0.077 +/- 0.008 g% at the end of the cooling period. Alcohol lowered the vasoconstriction threshold by 0.32 +/- 0.2 degrees C and elevated finger tip blood flow, but had no effect on thresholds for sweating and shivering or core cooling rate. Considering these minor effects it is unlikely that moderate alcohol consumption predisposes individuals to hypothermia or hyperthermia via impaired thermoregulation, but rather likely due to behavioral factors. PMID:8897037

  13. Successful Corticosteroid Treatment of Refractory Spontaneous Vasoconstriction of Extracranial Internal Carotid and Coronary Arteries

    PubMed Central

    Saito, Kozue; Kajimoto, Katsufumi; Nagatsuka, Kazuyuki

    2016-01-01

    Introduction: Spontaneous vasoconstriction of the extracranial internal carotid artery (SVEICA) is a rare cause of cerebral infarction. Most patients with SVEICA suffer recurrent attacks of vasoconstriction. The standard treatment for this condition has not been established and its long-term prognosis is unclear. Case Report: A 25-year-old man with a history of refractory vasospasm angina presented with transient alternating hemiplegia in both the right and left side. Serial carotid ultrasonography examinations showed severe transient stenosis or occlusion of cervical internal carotid arteries on 1 or both sides, with and without neurological symptoms. This condition resolved completely within 1 day to 1 week. The patient did not present any other risk factors for atherosclerosis and was diagnosed with SVEICA. The treatment with calcium antagonists and nitrates did not prevent the attacks. Administration of a corticosteroid substantially reduced the vasospasm attacks. Conclusions: SVEICA is intractable and difficult to diagnose. It has been reported that SVEICA sometimes complicates coronary artery disease, as observed in this case. The present case demonstrated the effectiveness of corticosteroid treatment against this disease. Serial ultrasonography examinations helped us to diagnose and follow-up the vasospasm attacks. PMID:27348139

  14. Unexpected High Incidence of Coronary Vasoconstriction in the Reduction of Microvascular Injury Using Sonolysis (ROMIUS) Trial.

    PubMed

    Roos, Sebastiaan T; Juffermans, Lynda J M; van Royen, Niels; van Rossum, Albert C; Xie, Feng; Appelman, Yolande; Porter, Thomas R; Kamp, Otto

    2016-08-01

    High-mechanical-index ultrasound and intravenous microbubbles might prove beneficial in treating microvascular obstruction caused by microthrombi after primary percutaneous coronary intervention for ST-segment elevation myocardial infarction (STEMI). Experiments in animals have revealed that longer-pulse-duration ultrasound is associated with an improvement in microvascular recovery. This trial tested long-pulse-duration, high-mechanical-index ultrasound in STEMI patients. Non-randomly assigned, non-blinded patients were included in this phase 2 trial. The primary endpoint was any side effect possibly related to the ultrasound treatment. The study was aborted after six patients were included; three patients experienced coronary vasoconstriction of the culprit artery, unresponsive to nitroglycerin. Therefore, coronary artery diameter was measured in five pigs. Coronary artery diameters distal to the injury site decreased after application of ultrasound, after balloon injury plus thrombus injection (from 1.89 ± 0.24 mm before to 1.78 ± 0.17 after ultrasound, p = 0.05). Long-pulse-duration ultrasound might cause coronary vasoconstriction distal to the culprit vessel location. PMID:27160847

  15. Dramatic Intracerebral Hemorrhagic Presentations of Reversible Cerebral Vasoconstriction Syndrome: Three Cases and a Literature Review

    PubMed Central

    Stary, Joel M.; Wang, Bonnie H.; Moon, Seong-Jin; Wang, Huan

    2014-01-01

    Reversible cerebral vasoconstriction syndrome (RCVS) refers to a number of disorders characterized by severe and sudden-onset (“thunderclap”) headaches and angiographic features of reversible, segmental, multifocal vasoconstriction of cerebral arteries. Although RCVS generally resolves without significant sequelae, a rare and possibly underrecognized hemorrhagic presentation has a worse potential course. We report three cases of hemorrhagic RCVS and review the literature. Three females (42, 54, and 33 years old, resp.) presented with severe headache, neurological deficits, and dramatic intracerebral hemorrhage (ICH). Patient 1 presented comatose with a 9 × 4 × 6.6 cm left deep intraparenchymal hemorrhage (IPH) and 1 cm midline shift. She underwent emergent surgical intervention. Patient 2 had a 3.3 × 1.5 cm left superior frontal IPH that enlarged to 4 × 2.5 cm within 12 hours with worsening headache and neurological deficits. She was successfully managed nonoperatively. Patient 3, after uncomplicated pregnancy and delivery, presented with a 1.5 cm left superior parietal IPH on postpartum day 7. Two days later, she acutely developed right hemiplegia. Repeat CT demonstrated a new 3.3 × 1.7 cm left frontal IPH. She was also successfully managed nonoperatively. Many diverse conditions are grouped within the category of RCVS. Dramatic ICH remains a rare and possibly underrecognized presenting feature. Prompt diagnosis and management are essential for obtaining the best outcome. PMID:24707417

  16. Reversible cerebral vasoconstriction syndrome associated with fingolimod treatment in relapsing-remitting multiple sclerosis three months after childbirth.

    PubMed

    Kraemer, Markus; Weber, Ralph; Herold, Michèle; Berlit, Peter

    2015-10-01

    Reversible cerebral vasoconstriction syndrome (RCVS) is characterized by acute thunderclap headache, evidence of vasoconstriction in conventional angiography or magnetic resonance angiography and reversibility of these phenomena within 12 weeks. Some triggering factors, for example drugs such as selective serotonin reuptake inhibitors, sumatriptan, tacrolimus, cyclophosphamide and cocaine, or states such as pregnancy, puerperium or migraine have been described. We describe the case of a 29-year-old woman with RCVS associated with fingolimod three months after childbirth. This case represents the first report of RCVS in fingolimod treatment. PMID:26283695

  17. Rheological regional properties of brain tissue studied under cyclic creep/ recovery shear stresses

    NASA Astrophysics Data System (ADS)

    Boudjema, F.; Lounis, M.; Khelidj, B.; Bessai, N.

    2015-04-01

    The rheological properties of brain tissue were studied by repeated creep-recovery shear tests under static conditions for different regions. Corpus callosum CC, Thalamus Th and Corona radiata CR. Non-linear viscoelastic model was also proposed to characterize the transient/steady states of shear creep results. From the creep-recovery data it was obvious that the brain tissues show high regional anisotropy. However. the both samples exhibit fluid viscoelastic properties in the first shear stress cycle of 100 Pa, while this behaviour evolutes to solid viscoelastic with cyclic effect.

  18. Modeling of Intrinsic Josephson Junctions in High Temperature Superconductors under External Radiation in the Breakpoint Region

    NASA Astrophysics Data System (ADS)

    Shukrinov, Yu. M.; Rahmonov, I. R.; Plecenik, A.; Streltsova, O. I.; Zuev, M. I.; Ososkov, G. A.

    2016-02-01

    The current-voltage (IV) characteristics of the intrinsic Josephson junctions in high temperature superconductors under external electromagnetic radiation are calculated numerically in the parametric resonance region. We discuss a numerical method for calculation of the Shapiro step width on the amplitude of radiation. In order to accelerate computations we used parallelization by task parameter via Simple Linux Utility for Resource Management (SLURM) arrays and tested it in the case of a single junction. An analysis of the junction transitions between rotating and oscillating states in the branching region of IV-characteristics is presented.

  19. Thermal Stability Analysis under Embankment with Asphalt Pavement and Cement Pavement in Permafrost Regions

    PubMed Central

    Jinping, Li; Xiaojuan, Quan

    2013-01-01

    The permafrost degradation is the fundamental cause generating embankment diseases and pavement diseases in permafrost region while the permafrost degradation is related with temperature. Based on the field monitoring results of ground temperature along G214 Highway in high temperature permafrost regions, both the ground temperatures in superficial layer and the annual average temperatures under the embankment were discussed, respectively, for concrete pavements and asphalt pavements. The maximum depth of temperature field under the embankment for concrete pavements and asphalt pavements was also studied by using the finite element method. The results of numerical analysis indicate that there were remarkable seasonal differences of the ground temperatures in superficial layer between asphalt pavement and concrete pavement. The maximum influencing depth of temperature field under the permafrost embankment for every pavement was under the depth of 8 m. The thawed cores under both embankments have close relation with the maximum thawed depth, the embankment height, and the service time. The effective measurements will be proposed to keep the thermal stabilities of highway embankment by the results. PMID:24027444

  20. Regional temperature and precipitation changes under high-end (≥4°C) global warming.

    PubMed

    Sanderson, M G; Hemming, D L; Betts, R A

    2011-01-13

    Climate models vary widely in their projections of both global mean temperature rise and regional climate changes, but are there any systematic differences in regional changes associated with different levels of global climate sensitivity? This paper examines model projections of climate change over the twenty-first century from the Intergovernmental Panel on Climate Change Fourth Assessment Report which used the A2 scenario from the IPCC Special Report on Emissions Scenarios, assessing whether different regional responses can be seen in models categorized as 'high-end' (those projecting 4°C or more by the end of the twenty-first century relative to the preindustrial). It also identifies regions where the largest climate changes are projected under high-end warming. The mean spatial patterns of change, normalized against the global rate of warming, are generally similar in high-end and 'non-high-end' simulations. The exception is the higher latitudes, where land areas warm relatively faster in boreal summer in high-end models, but sea ice areas show varying differences in boreal winter. Many continental interiors warm approximately twice as fast as the global average, with this being particularly accentuated in boreal summer, and the winter-time Arctic Ocean temperatures rise more than three times faster than the global average. Large temperature increases and precipitation decreases are projected in some of the regions that currently experience water resource pressures, including Mediterranean fringe regions, indicating enhanced pressure on water resources in these areas. PMID:21115514

  1. Hypoxic pulmonary vasoconstriction in isolated rat pulmonary arteries is not inhibited by antagonists of H2 S-synthesizing pathways.

    PubMed

    Prieto-Lloret, Jesus; Shaifta, Yasin; Ward, Jeremy P T; Aaronson, Philip I

    2015-01-15

    An increase in the H2 S (hydrogen sulphide, hereafter sulphide) concentration in pulmonary artery smooth muscle cells (PASMCs) has been proposed to mediate hypoxic pulmonary vasoconstriction (HPV). We evaluated this hypothesis in isolated rat intrapulmonary arteries (IPAs) by examining the effects of the sulphide precursor cysteine and sulphide-synthesis blockers on HPV and also on normoxic pulmonary vasoconstriction (NPV) stimulated by prostaglandin F2α (PGF2α ) and by the drug LY83583, which causes contraction in IPAs by increasing cellular reactive oxygen species levels. Experiments with several blockers of cystathionine γ-lyase (CSE), the enzyme responsible for sulphide synthesis in the vasculature, demonstrated that propargylglycine (PAG, 1 mm) had little or no effect on the NPV caused by PGF2α or LY83583. Conversely, other CSE antagonists tested, aminooxyacetic acid (AOAA, 100 μm), β-cyanoalanine (BCA, 500 μm) and hydroxylamine (HA, 100 μm), altered the NPV to PGF2α (BCA increased, HA inhibited) and/or LY83583 (BCA increased, AOAA and HA inhibited). Preincubating IPAs in physiological saline solution (PSS) containing 1 mm cysteine increased the amplitude of the NPV to PGF2(α) by ∼50%, and had a similar effect on HPV elicited by hypoxic challenge with 0% O2 . The enhancement of both responses by cysteine was abolished by pretreatment with 1 mm PAG. Measurements carried out with an amperometric electrode demonstrated that incubation with 1 mm cysteine under anoxic conditions (to minimize sulphide oxidation) greatly potentiated the release of sulphide from pieces of rat liver and that this release was strongly antagonized by PAG, indicating that at this concentration PAG could enter cells intact and antagonize CSE. PAG at 1 mm had no effect on HPV recorded in control PSS, or in PSS supplemented with physiological concentrations of cysteine (10 μm), cystine (50 μm) and glutamate (100 μm) in order to prevent the possible depletion of intracellular

  2. Hypoxic pulmonary vasoconstriction in isolated rat pulmonary arteries is not inhibited by antagonists of H2S-synthesizing pathways

    PubMed Central

    Prieto-Lloret, Jesus; Shaifta, Yasin; Ward, Jeremy P T; Aaronson, Philip I

    2015-01-01

    An increase in the H2S (hydrogen sulphide, hereafter sulphide) concentration in pulmonary artery smooth muscle cells (PASMCs) has been proposed to mediate hypoxic pulmonary vasoconstriction (HPV). We evaluated this hypothesis in isolated rat intrapulmonary arteries (IPAs) by examining the effects of the sulphide precursor cysteine and sulphide-synthesis blockers on HPV and also on normoxic pulmonary vasoconstriction (NPV) stimulated by prostaglandin F2α (PGF2α) and by the drug LY83583, which causes contraction in IPAs by increasing cellular reactive oxygen species levels. Experiments with several blockers of cystathionine γ-lyase (CSE), the enzyme responsible for sulphide synthesis in the vasculature, demonstrated that propargylglycine (PAG, 1 mm) had little or no effect on the NPV caused by PGF2α or LY83583. Conversely, other CSE antagonists tested, aminooxyacetic acid (AOAA, 100 μm), β-cyanoalanine (BCA, 500 μm) and hydroxylamine (HA, 100 μm), altered the NPV to PGF2α (BCA increased, HA inhibited) and/or LY83583 (BCA increased, AOAA and HA inhibited). Preincubating IPAs in physiological saline solution (PSS) containing 1 mm cysteine increased the amplitude of the NPV to PGF2α by ∼50%, and had a similar effect on HPV elicited by hypoxic challenge with 0% O2. The enhancement of both responses by cysteine was abolished by pretreatment with 1 mm PAG. Measurements carried out with an amperometric electrode demonstrated that incubation with 1 mm cysteine under anoxic conditions (to minimize sulphide oxidation) greatly potentiated the release of sulphide from pieces of rat liver and that this release was strongly antagonized by PAG, indicating that at this concentration PAG could enter cells intact and antagonize CSE. PAG at 1 mm had no effect on HPV recorded in control PSS, or in PSS supplemented with physiological concentrations of cysteine (10 μm), cystine (50 μm) and glutamate (100 μm) in order to prevent the possible depletion of

  3. Carotid endarterectomy under regional analgesia:a retrospective study (1988-1999).

    PubMed

    Singh, S M; Rajmohan, T; Juneja, R; Mehta, Y; Trehan, N

    2001-01-01

    The procedure of carotid endarterectomy is more or less standardized. Controversies persist on many technical issues, one of which is general versus regional anaesthesia. We retrospectively evaluated the influence of regional analgesia on perioperative complications, the hospital stay and the perioperative mortality after carotid endarterectomy in 53 patients. All the patients in the study received deep cervical block regional anaesthesia (Winne's technique) for carotid endarterectomy. Indications for surgery included transient ischaemic haemodynamically significant stenosis. Shunt was used in 7 cases (13.2%). General anaesthesia was supplemented in 2 patients (3.8%). There was no perioperative mortality. Permanent non-fatal neurologic deficit occurred in 1 patient (1.9%) and temporary neurologic Deficit occurred in 1 patient (1.9%). The mean ICU stay was 1.85 (+/-0.82) days and the hospital stay was 5.2 (+/-1.14) days. On the basis of our data we believe that under regional anaesthesia carotid endarterectomy can be performed with acceptable complications and that regional anaesthetic technique is safe and well tolerated by the patients. PMID:17851155

  4. Vasoconstrictive responses of the testicular and caudal arteries in bulls exposed to ergot alkaloids from tall fescue

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Color Doppler ultasonography was used to evaluate vasoconstrictive responses of the testicular artery in yearling bulls to ergot alkaloids. Ergot alkaloid-induced constriction of the testicular artery could disrupt thermoregulation of the testes and reduce bull fertility. Luminal areas of the test...

  5. Reversible cerebral vasoconstriction syndrome with multivessel cervical artery dissections and a double aortic arch.

    PubMed

    Nouh, Amre; Ruland, Sean; Schneck, Michael J; Pasquale, David; Biller, José

    2014-02-01

    Reversible cerebral vasoconstriction syndrome (RCVS) has been associated with exposure to vasoactive substances and few reports with cervical arterial dissections (CADs). We evaluated a 32-year-old woman with history of depression, migraines without aura, and cannabis use who presented with a thunderclap headache unresponsive to triptans. She was found to have bilateral occipital infarcts, bilateral extracranial vertebral artery dissections, bilateral internal carotid artery dissecting aneurysms, and extensive distal multifocal segmental narrowing of the anterior and posterior intracranial circulation with a "sausage on a string-like appearance" suggestive of RCVS. Subsequently, she was found to have a distal thrombus of the basilar artery, was anticoagulated, and discharged home with no residual deficits. We highlight the potential association of CADs and RCVS. The association of RCVS and a double aortic arch has not been previously reported. PMID:24103665

  6. Changes in capillary filling do not influence inspiratory-induced vasoconstrictive episodes

    NASA Astrophysics Data System (ADS)

    Rauh, Robert; Ochsmann, Elke; Kessler, Manfred; Mueck-Weymann, Michael

    2007-05-01

    Deep inspiration leads to sympathetically mediated vasoconstriction at the fingertip. This so-called inspiratory gasp response (IGR) is usually assessed by laser Doppler fluxmetry (LDF) and provides interesting information on the activity of the sympathetic nervous system. In this study we investigated if simple maneuvers which affect microcirculation have an effect on the IGR. For this we detected IGR with LDF in rest, after elevation of the arm to lower capillary filling, after venous congestion to increase capillary filling, and after heating up in warm water to induce vasodilation. Capillary filling was monitored with the Erlangen Microlightguide Spectrophotometer (EMPHO) by determination of the relative hemoglobin concentration. We found that IGR was not affected by microcirculatory starting conditions. Therefore, we conclude that diagnostic results of the IGR are not influenced by different capillary filling levels.

  7. Vasoconstriction by Electrical Stimulation: New Approach to Control of Non-Compressible Hemorrhage

    PubMed Central

    Mandel, Yossi; Manivanh, Richard; Dalal, Roopa; Huie, Phil; Wang, Jenny; Brinton, Mark; Palanker, Daniel

    2013-01-01

    Non-compressible hemorrhage is the most common preventable cause of death on battlefield and in civilian traumatic injuries. We report the use of microsecond pulses of electric current to induce rapid constriction in femoral and mesenteric arteries and veins in rats. Electrically-induced vasoconstriction could be induced in seconds while blood vessels dilated back to their original size within minutes after stimulation. At higher settings, a blood clotting formed, leading to complete and permanent occlusion of the vessels. The latter regime dramatically decreased the bleeding rate in the injured femoral and mesenteric arteries, with a complete hemorrhage arrest achieved within seconds. The average blood loss from the treated femoral artery during the first minute after injury was about 7 times less than that of a non-treated control. This new treatment modality offers a promising approach to non-damaging control of bleeding during surgery, and to efficient hemorrhage arrest in trauma patients. PMID:23828130

  8. Effects of task difficulty and invested mental effort on peripheral vasoconstriction.

    PubMed

    Iani, Cristina; Gopher, Daniel; Lavie, Peretz

    2004-09-01

    We ran two experiments to investigate whether peripheral arterial tone reflects changes in mental effort. Finger pulse wave amplitude, interpulse interval, and pulse variability in the mid- and high-frequency bands were recorded by means of a newly developed finger plethysmograph during both rest and cognitive performance. Using a modified version of the Sternberg memory task, we selectively manipulated either the difficulty of the task (Experiment 1) or the subjects' level of engagement in the task (Experiment 2). We found a significant difference in finger pulse wave amplitude between rest and task periods, suggesting that the measure reflects changes in sympathetic activity due to task engagement. In addition, our results suggest that reduced pulse wave amplitude, signaling vasoconstriction, occurs when subjects are investing effort. PMID:15318885

  9. Protein kinases in vascular smooth muscle tone--role in the pulmonary vasculature and hypoxic pulmonary vasoconstriction.

    PubMed

    Ward, Jeremy P T; Knock, Greg A; Snetkov, Vladimir A; Aaronson, Philip I

    2004-12-01

    Hypoxic pulmonary vasoconstriction (HPV) is an adaptive mechanism that in the normal animal diverts blood away from poorly ventilated areas of the lung, thereby maintaining optimal ventilation-perfusion matching. In global hypoxia however, such as in respiratory disease or at altitude, it causes detrimental increases in pulmonary vascular resistance and pulmonary artery (PA) pressure. The precise intracellular pathways and mechanisms underlying HPV remain unclear, although it is now recognised that both an elevation in smooth muscle intracellular [Ca2+] and a concomitant increase in Ca2+ sensitivity are involved. Several key intracellular protein kinases have been proposed as components of the signal transduction pathways leading to development of HPV, specifically Rho kinase, non-receptor tyrosine kinases (NRTK), p38 mitogen activated protein (MAP) kinase, and protein kinase C (PKC). All of these have been implicated to a greater or lesser extent in pathways leading to Ca2+ sensitisation, and in some cases regulation of intracellular [Ca2+] as well. In this article, we review the role of these key protein kinases in the regulation of vascular smooth muscle (VSM) constriction, applying what is known in the systemic circulation to the pulmonary circulation and HPV. We conclude that the strongest evidence for direct involvement of protein kinases in the mechanisms of HPV concerns a central role for Rho kinase in Ca2+ sensitisation, and a potential role for Src-family kinases in both modulation of Ca2+ entry via capacitative Ca2+ entry (CCE) and activation of Rho kinase, though others are likely to have indirect or modulatory influences. In addition, we speculate that Src family kinases may provide a central interface between the proposed hypoxia-induced generation of reactive oxygen species by mitochondria and both the elevation in intracellular [Ca2+] and Rho kinase mediated Ca2+ sensitisation. PMID:15556675

  10. Periodic, profound peripheral vasoconstriction--a new marker of obstructive sleep apnea.

    PubMed

    Schnall, R P; Shlitner, A; Sheffy, J; Kedar, R; Lavie, P

    1999-11-01

    We report a novel approach to the determination of sleep apnea based on measuring the peripheral circulatory responses in a primary condition of disordered breathing. The apparatus is a finger plethysmograph coupled to a constant volume, variable pressure, pneumatic system. The plethysmograph's tip (measurement site) is composed of two parallel opposing longitudinal half thimbles, which is attached to a contiguous annular cuff. Each compartment consists of an internal membrane surrounded by an outer rigid wall. These provide a uniform pressure field and impart a two-point locking action preventing axial and longitudinal motion of the finger. Subdiastolic pressure is applied to prevent venous pooling, engorgement, and stasis, to inhibit retrograde venous shock wave propagation and partially unload arterial wall tension. The annular cuff extends the effective boundary of the pressure field beyond the measuring site. In 42 patients with Obstructive Sleep Apnea Syndrome (OSAS) profound, transient vasoconstriction and tachycardia usually of a periodic nature, were clearly seen with each apneic event, possibly related to transient arousal. Good agreement was found between standard total apnea-hypopnea scoring, 129.5+/-22.4 (Mean +/- SEM), and transient vasoconstriction and tachycardia events, 121.2+/-19.4 (R = .92, p<.0001). We conclude that the finger tip exemplifies the scope of peripheral vascular responsiveness due to its high density of alpha sympathetic innervation, and its high degree of blood flow rate lability. Given that elevated peripheral resistance and tightly linked transient heart rate elevation is a consistent part of the hemodynamic response to arousal and OSAS, we believe that pulsatile finger blood flow patterns can be clearly diagnostic of OSAS and other sleep-disordered breathing conditions. PMID:10566912

  11. The clinical and radiological spectrum of reversible cerebral vasoconstriction syndrome. A prospective series of 67 patients.

    PubMed

    Ducros, Anne; Boukobza, Monique; Porcher, Raphaël; Sarov, Mariana; Valade, Dominique; Bousser, Marie-Germaine

    2007-12-01

    Reversible cerebral vasoconstriction syndrome (RCVS) is characterized by the association of severe headaches with or without additional neurological symptoms and a 'string and beads' appearance on cerebral arteries, which resolves spontaneously in 1-3 months. We present the clinical, neuroimaging and outcome data of 67 consecutive patients prospectively diagnosed over 3 years in our institution with an angiographically confirmed RCVS. There were 43 females and 24 males with a mean age of 42 years (19-70). RCVS was spontaneous in 37% of patients and secondary in the 63% others, to postpartum in 5 and to exposure to various vasoactive substances in 37, mainly cannabis, selective serotonin-recapture inhibitors and nasal decongestants. The main pattern of presentation (94% of patients) was multiple thunderclap headaches recurring over a mean period of 1 week. In 51 patients (76%), headaches resumed the clinical presentation. Various complications were observed, with different time courses. Cortical subarachnoid haemorrhage (cSAH) (22%), intracerebral haemorrhage (6%), seizures (3%) and reversible posterior leukoencephalopathy (9%) were early complications, occurring mainly within the first week. Ischaemic events, including TIAs (16%) and cerebral infarction (4%), occurred significantly later than haemorrhagic events, mainly during the second week. Significant sex differences were observed: women were older, had more frequent single-drug exposure and a higher rate of stroke and cSAH. Sixty-one patients were treated by nimodipine: 36% had recurrent headaches, 7% TIAs and one multiple infarcts. The different time courses of thunderclap headaches, vasoconstriction and strokes suggest that the responsible vasospastic disorder starts distally and progresses towards medium sized and large arteries. No relapse was observed during the 16 +/- 12.4 months of follow-up. Our data suggest that RCVS is more frequent than previously thought, is more often secondary particularly to

  12. Natural variation in non-coding regions underlying phenotypic diversity in budding yeast

    PubMed Central

    Salinas, Francisco; de Boer, Carl G.; Abarca, Valentina; García, Verónica; Cuevas, Mara; Araos, Sebastian; Larrondo, Luis F.; Martínez, Claudio; Cubillos, Francisco A.

    2016-01-01

    Linkage mapping studies in model organisms have typically focused their efforts in polymorphisms within coding regions, ignoring those within regulatory regions that may contribute to gene expression variation. In this context, differences in transcript abundance are frequently proposed as a source of phenotypic diversity between individuals, however, until now, little molecular evidence has been provided. Here, we examined Allele Specific Expression (ASE) in six F1 hybrids from Saccharomyces cerevisiae derived from crosses between representative strains of the four main lineages described in yeast. ASE varied between crosses with levels ranging between 28% and 60%. Part of the variation in expression levels could be explained by differences in transcription factors binding to polymorphic cis-regulations and to differences in trans-activation depending on the allelic form of the TF. Analysis on highly expressed alleles on each background suggested ASN1 as a candidate transcript underlying nitrogen consumption differences between two strains. Further promoter allele swap analysis under fermentation conditions confirmed that coding and non-coding regions explained aspartic and glutamic acid consumption differences, likely due to a polymorphism affecting Uga3 binding. Together, we provide a new catalogue of variants to bridge the gap between genotype and phenotype. PMID:26898953

  13. Natural variation in non-coding regions underlying phenotypic diversity in budding yeast.

    PubMed

    Salinas, Francisco; de Boer, Carl G; Abarca, Valentina; García, Verónica; Cuevas, Mara; Araos, Sebastian; Larrondo, Luis F; Martínez, Claudio; Cubillos, Francisco A

    2016-01-01

    Linkage mapping studies in model organisms have typically focused their efforts in polymorphisms within coding regions, ignoring those within regulatory regions that may contribute to gene expression variation. In this context, differences in transcript abundance are frequently proposed as a source of phenotypic diversity between individuals, however, until now, little molecular evidence has been provided. Here, we examined Allele Specific Expression (ASE) in six F1 hybrids from Saccharomyces cerevisiae derived from crosses between representative strains of the four main lineages described in yeast. ASE varied between crosses with levels ranging between 28% and 60%. Part of the variation in expression levels could be explained by differences in transcription factors binding to polymorphic cis-regulations and to differences in trans-activation depending on the allelic form of the TF. Analysis on highly expressed alleles on each background suggested ASN1 as a candidate transcript underlying nitrogen consumption differences between two strains. Further promoter allele swap analysis under fermentation conditions confirmed that coding and non-coding regions explained aspartic and glutamic acid consumption differences, likely due to a polymorphism affecting Uga3 binding. Together, we provide a new catalogue of variants to bridge the gap between genotype and phenotype. PMID:26898953

  14. Beyond optimality: Multistakeholder robustness tradeoffs for regional water portfolio planning under deep uncertainty

    NASA Astrophysics Data System (ADS)

    Herman, Jonathan D.; Zeff, Harrison B.; Reed, Patrick M.; Characklis, Gregory W.

    2014-10-01

    While optimality is a foundational mathematical concept in water resources planning and management, "optimal" solutions may be vulnerable to failure if deeply uncertain future conditions deviate from those assumed during optimization. These vulnerabilities may produce severely asymmetric impacts across a region, making it vital to evaluate the robustness of management strategies as well as their impacts for regional stakeholders. In this study, we contribute a multistakeholder many-objective robust decision making (MORDM) framework that blends many-objective search and uncertainty analysis tools to discover key tradeoffs between water supply alternatives and their robustness to deep uncertainties (e.g., population pressures, climate change, and financial risks). The proposed framework is demonstrated for four interconnected water utilities representing major stakeholders in the "Research Triangle" region of North Carolina, U.S. The utilities supply well over one million customers and have the ability to collectively manage drought via transfer agreements and shared infrastructure. We show that water portfolios for this region that compose optimal tradeoffs (i.e., Pareto-approximate solutions) under expected future conditions may suffer significantly degraded performance with only modest changes in deeply uncertain hydrologic and economic factors. We then use the Patient Rule Induction Method (PRIM) to identify which uncertain factors drive the individual and collective vulnerabilities for the four cooperating utilities. Our framework identifies key stakeholder dependencies and robustness tradeoffs associated with cooperative regional planning, which are critical to understanding the tensions between individual versus regional water supply goals. Cooperative demand management was found to be the key factor controlling the robustness of regional water supply planning, dominating other hydroclimatic and economic uncertainties through the 2025 planning horizon. Results

  15. Region-Based Association Test for Familial Data under Functional Linear Models.

    PubMed

    Svishcheva, Gulnara R; Belonogova, Nadezhda M; Axenovich, Tatiana I

    2015-01-01

    Region-based association analysis is a more powerful tool for gene mapping than testing of individual genetic variants, particularly for rare genetic variants. The most powerful methods for regional mapping are based on the functional data analysis approach, which assumes that the regional genome of an individual may be considered as a continuous stochastic function that contains information about both linkage and linkage disequilibrium. Here, we extend this powerful approach, earlier applied only to independent samples, to the samples of related individuals. To this end, we additionally include a random polygene effects in functional linear model used for testing association between quantitative traits and multiple genetic variants in the region. We compare the statistical power of different methods using Genetic Analysis Workshop 17 mini-exome family data and a wide range of simulation scenarios. Our method increases the power of regional association analysis of quantitative traits compared with burden-based and kernel-based methods for the majority of the scenarios. In addition, we estimate the statistical power of our method using regions with small number of genetic variants, and show that our method retains its advantage over burden-based and kernel-based methods in this case as well. The new method is implemented as the R-function 'famFLM' using two types of basis functions: the B-spline and Fourier bases. We compare the properties of the new method using models that differ from each other in the type of their function basis. The models based on the Fourier basis functions have an advantage in terms of speed and power over the models that use the B-spline basis functions and those that combine B-spline and Fourier basis functions. The 'famFLM' function is distributed under GPLv3 license and is freely available at http://mga.bionet.nsc.ru/soft/famFLM/. PMID:26111046

  16. Statistical modelling of grapevine yield in the Port Wine region under present and future climate conditions

    NASA Astrophysics Data System (ADS)

    Santos, João A.; Malheiro, Aureliano C.; Karremann, Melanie K.; Pinto, Joaquim G.

    2011-03-01

    The impact of projected climate change on wine production was analysed for the Demarcated Region of Douro, Portugal. A statistical grapevine yield model (GYM) was developed using climate parameters as predictors. Statistically significant correlations were identified between annual yield and monthly mean temperatures and monthly precipitation totals during the growing cycle. These atmospheric factors control grapevine yield in the region, with the GYM explaining 50.4% of the total variance in the yield time series in recent decades. Anomalously high March rainfall (during budburst, shoot and inflorescence development) favours yield, as well as anomalously high temperatures and low precipitation amounts in May and June (May: flowering and June: berry development). The GYM was applied to a regional climate model output, which was shown to realistically reproduce the GYM predictors. Finally, using ensemble simulations under the A1B emission scenario, projections for GYM-derived yield in the Douro Region, and for the whole of the twenty-first century, were analysed. A slight upward trend in yield is projected to occur until about 2050, followed by a steep and continuous increase until the end of the twenty-first century, when yield is projected to be about 800 kg/ha above current values. While this estimate is based on meteorological parameters alone, changes due to elevated CO2 may further enhance this effect. In spite of the associated uncertainties, it can be stated that projected climate change may significantly benefit wine yield in the Douro Valley.

  17. Application of colour magnification technique for revealing skin microcirculation changes under regional anaesthetic input

    NASA Astrophysics Data System (ADS)

    Rubins, Uldis; Spigulis, Janis; Miscuks, Aleksejs

    2013-11-01

    In this work the colour magnification technique was applied for monitoring of palm skin microcirculation changes under peripheral (Plexus Brachialis with axiliary access) Regional Anaesthesia (RA). During the RA procedure 20 minute video of patient's forearm was taken at steady light conditions. Video content was processed offline by custom developed Matlab software with build-in colour magnification algorithm that performs temporal filtering of video sequence near-heartbeat frequency, spatial decomposition of video and amplification of pulsatile signal in every pixel of skin image. Using this method, we are able to visualize the subcutaneous microcirculation changes in high spatial resolution. The results showed different blood pulse amplitude dynamics over the skin regions of palm and forearm during the RA. The colour magnification technique could be used for real-time monitoring of RA effect.

  18. Early rehabilitation after anterior cruciate ligament reconstruction under regional analgesia: a case report.

    PubMed

    Al-Nasser, Bassam; Palacios, Jean Luc; Lapasset, Lionel; Hattée, Bernard; Leroy, Frédéric

    2004-02-01

    Patients undergoing major knee surgery may experience postoperative pain, which could be exacerbated by early postoperative continuous passive motion or active mobilization. This pain may result in poor functional recovery. Use of regional analgesia techniques to achieve more consistent pain relief and to facilitate rapid rehabilitation can play an important role in optimizing postoperative outcome after anterior cruciate ligament repair (ACLR). This case study concerns a 20-year-old male soldier, otherwise healthy, who underwent ACLR. We inserted a catheter in the fascia iliaca compartment and performed postoperative analgesia with low-concentration ropivacaine by using an elastomeric pump. The patient started early rehabilitation under fascia iliaca compartment analgesia. We discuss the case and the influence of regional analgesia techniques on postoperative and clinical outcomes. PMID:14966725

  19. Regional crop productivity and greenhouse gas emissions from Swiss soils under organic farming

    NASA Astrophysics Data System (ADS)

    Lee, Juhwan; Necpalova, Magdalena; Six, Johan

    2016-04-01

    There is worldwide concern about the increase in atmospheric greenhouse gases (GHG) and their impact on climate change and food security. As a sustainable alternative, organic cropping in various forms has been promoted to minimize the environmental impacts of conventional practices. However, relatively little is known about the potential to reduce GHG emissions while maintaining crop productivity through the large-scale adoption of organic practices. Therefore, we simulated and compared regional crop production, soil organic carbon status, and net soil GHG emissions under organic and conventional practices. Grid-level (2.2 km by 2.2 km) simulation was performed using previously validated DailyDayCent by considering typical crop rotations. Regional model estimates are presented and discussed specifically with the focus on Swiss organic and conventional cropping systems, which differ by type and intensity of manuring, tillage, and cover crop.

  20. [Stunting and emaciation in children under 5 in distinct regions and strata in Mexico].

    PubMed

    Rivera-Dommarco, J; González-Cossío, T; Flores, M; Hernández-Avila, M; Lezana, M A; Sepúlveda-Amor, J

    1995-01-01

    Data from a National Nutrition Survey conducted in 1988 in a probability sample of 13,236 households and 17,426 children under five, representative at the national level and for four regions (North, Center, South, and Mexico City), were analyzed. Risks for wasting and stunting and odds ratios were obtained by region, by district according to proportion of indigenous population and by level of urbanization, by level of education of both parents, by gender, and by various combinations of the former strata. A high risk of stunting and a low risk of wasting were found. The risk of stunting is greater in predominantly indigenous and rural districts, in the South and Center, and in families of mothers with low education and poor housing conditions. The results can be used for food and nutrition policy planning and for targeting nutrition intervention programs. PMID:7618120

  1. The Future of Food: Regional Adaptation Strategies for Optimizing Grain Yields Under Climate Change

    NASA Astrophysics Data System (ADS)

    Nicholas, K. A.; Chhetri, N.; Girvetz, E. H.; McCarthy, H. R.; Twine, T. E.; Ummenhofer, C. C.

    2010-12-01

    Current projections of crop yields under climate change generally neglect to account for the potential for farmer adaptation to counteract environmental drivers of yield decreases, but such adaptation will be increasingly important for food security. We used a process-based crop model (Agro-IBIS) and a suite of climate projections based on multiple IPCC AR4 models under three greenhouse gas emission scenarios to project climate change impacts to yield of maize in Free State, South Africa, and Iowa, USA, and of wheat in Victoria, Australia, and Punjab, India. We found, for example in Iowa, that projected substantial increases in temperatures and slight decreases in precipitation result in a compressed growing period, with peak productivity occurring in mid-May rather than mid-July and yield decreasing by up to 40% below current levels by the end of the century. We then used this information to identify regionally-specific adaptation strategies by examining climate-limiting factors on the timing of harvest and quantity of yields in each location, and the current growing practices and resource availability. These adaptation strategies were developed with the intention of replicating current yields at current timing (for example, by selecting longer-ripening cultivars) and also to optimize yields under the new climate regime (for example, by double-cropping a maize/soy rotation in the same growing season). All in all, this research shows that promising adaptation options exist in each region, and highlight the need for sophisticated and regionally-sensitive adaptation strategies to sustain and increase food production in the 21st century.

  2. Critical regions of heat transfer during the nucleate boiling of oxygen under conditions of reduced gravity

    NASA Astrophysics Data System (ADS)

    Kirichenko, Iu. A.; Gladchenko, G. M.; Rusanov, K. V.

    1984-11-01

    Heat transfer during the nucleate boiling of liquid oxygen under conditions of simulated microgravity is investigated experimentally over a wide range of pressures (600-70,000 Pa) and relative accelerations (0.01-1). The objective of the study is to verify some of the existing models for the critical region of heat transfer. Formulas are obtained yielding different acceleration dependences of the critical density of the heat flux for high and low pressures, which is consistent with experimental data on oxygen boiling.

  3. A sharp Moho step under the Central and Eastern Betics, Western Mediterranean region.

    NASA Astrophysics Data System (ADS)

    de Lis Mancilla, Flor; Heit, Benjamin; Morales, Jose; Heit, Xiaohui; Molina-Aguilera, Antonio; Stich, Daniel

    2015-04-01

    We map the lithospheric structure under the central and eastern Betics (western Mediterranean region) interpreting P-receiver functions obtained from two dense seismic profiles (HIRE and Transcorbe profiles of ~120 km and 160 km of length, respectively). The goal is to study the lithospheric structure and its variations between the different geological domains, from the Alboran domain in the south (metamorphic rocks), the External zones (sedimentary rocks) and the Variscan terrains of the Iberian Massif in the north. One of the profiles (HIRE), North-South oriented, crosses the Sierra Nevada Mountains, one of the prominent features in the Western Mediterranean tectonic region with the highest topography of the Iberia peninsula (~3400 m). The spacing between stations, around 2km, allows mapping with high accuracy of the variations of the crustal structure. We observe a sharp Moho step of ~15 km under the Internal zones of the Alboran domain coinciding the thinner crust with the highest topography along the profile. This agrees with the prior hypothesis about the lack of crustal root underneath Sierra Nevada Mountains and opens a question about the source of the dynamic compensation of its topography. Previous studies showed that the Iberian crust understrust the Alboran domain under its contact with the External zones observing the presence of slab-type feature of Iberian lithosphere at the western Betics while tearing and delamination of this Iberian slab is proposed at eastern Betics. We observe that the Iberian crust undertrust the Alboran domain and terminate sharply under the contact between the Alpujarride and the Nevado-Filabre complexes (Alboran domain).

  4. Dahl SS rats demonstrate enhanced aortic perivascular adipose tissue-mediated buffering of vasoconstriction through activation of NOS in the endothelium.

    PubMed

    Spradley, Frank T; Ho, Dao H; Pollock, Jennifer S

    2016-02-01

    Perivascular adipose tissue (PVAT) mediates buffering of vasoconstriction through activation of endothelium-derived factors. We hypothesized that the PVAT of Dahl salt-sensitive (Dahl SS) rats has reduced ability to buffer vasoconstriction. Vascular reactivity experiments were performed on aortic rings with PVAT intact (+PVAT) or removed (-PVAT), and endothelium intact (+ENDO) or removed (-ENDO) from Dahl SS rats and control SS.13(BN) rats (Dahl SS rats that have had chromosome 13 completely replaced with that of the Brown Norway rat, rendering this strain insensitive to high-salt or high-fat diet-induced hypertension). Endothelial dysfunction, assessed by ACh-mediated vasorelaxation, was confirmed in aortic rings of Dahl SS rats. The +PVAT+ENDO aortic rings had indistinguishable phenylephrine-induced vasoconstriction between genotypes. In both strains, removal of PVAT significantly enhanced vasoconstriction. Dahl SS rat -PVAT+ENDO aortic rings displayed exaggerated vasoconstriction to phenylephrine vs. SS.13(BN) rats, indicating that PVAT-mediated buffering of vasoconstriction was greater in Dahl SS rats. Removal of both the ENDO and PVAT restored vasoconstriction in both strains. The nitric oxide synthase (NOS) inhibitor, N(ω)-nitro-L-arginine methyl ester (L-NAME), produced a similar effect as that seen with -ENDO. These data indicate that the function of the PVAT to activate endothelium-derived NOS is enhanced in Dahl SS compared with SS.13(BN) rats and, most likely, occurs through a pathway that is distinct from ACh-mediated activation of NOS. PVAT weight and total PVAT leptin levels were greater in Dahl SS rats. Leptin induced a significantly decreased vasoconstriction in -PVAT+ENDO aortic rings from Dahl SS rats, but not SS.13(BN) rats. In contrast to our initial hypothesis, PVAT in Dahl SS rats buffers vasoconstriction by activating endothelial NOS via mechanisms that may include the involvement of leptin. Thus, the PVAT serves a vasoprotective role in

  5. Regional modelling of nitrate leaching from Swiss organic and conventional cropping systems under climate change

    NASA Astrophysics Data System (ADS)

    Calitri, Francesca; Necpalova, Magdalena; Lee, Juhwan; Zaccone, Claudio; Spiess, Ernst; Herrera, Juan; Six, Johan

    2016-04-01

    Organic cropping systems have been promoted as a sustainable alternative to minimize the environmental impacts of conventional practices. Relatively little is known about the potential to reduce NO3-N leaching through the large-scale adoption of organic practices. Moreover, the potential to mitigate NO3-N leaching and thus the N pollution under future climate change through organic farming remain unknown and highly uncertain. Here, we compared regional NO3-N leaching from organic and conventional cropping systems in Switzerland using a terrestrial biogeochemical process-based model DayCent. The objectives of this study are 1) to calibrate and evaluate the model for NO3-N leaching measured under various management practices from three experiments at two sites in Switzerland; 2) to estimate regional NO3-N leaching patterns and their spatial uncertainty in conventional and organic cropping systems (with and without cover crops) for future climate change scenario A1B; 3) to explore the sensitivity of NO3-N leaching to changes in soil and climate variables; and 4) to assess the nitrogen use efficiency for conventional and organic cropping systems with and without cover crops under climate change. The data for model calibration/evaluation were derived from field experiments conducted in Liebefeld (canton Bern) and Eschikon (canton Zürich). These experiments evaluated effects of various cover crops and N fertilizer inputs on NO3-N leaching. The preliminary results suggest that the model was able to explain 50 to 83% of the inter-annual variability in the measured soil drainage (RMSE from 12.32 to 16.89 cm y-1). The annual NO3-N leaching was also simulated satisfactory (RMSE = 3.94 to 6.38 g N m-2 y-1), although the model had difficulty to reproduce the inter-annual variability in the NO3-N leaching losses correctly (R2 = 0.11 to 0.35). Future climate datasets (2010-2099) from the 10 regional climate models (RCM) were used in the simulations. Regional NO3-N leaching

  6. Global and regional temperature metrics under a two-basket approach

    NASA Astrophysics Data System (ADS)

    Tanaka, Katsumasa; Cherubini, Francesco

    2015-04-01

    Climate and environmental policies and assessments including the Life Cycle Assessments (LCA) commonly employ a single basket approach, in which emissions of non-CO2 components are aggregated into their CO2 equivalents through emission metrics. Such metrics entail various assumptions, which can give rise to a large difference in metric values particularly for near-term climate forcers (NTCFs) (e.g., Tanaka et al., 2013). The difficulties in equating emissions of CO2 and NTCFs led to a proposal of a two-basket approach, which allows emission conversions among species with comparable atmospheric lifetimes (e.g., Cherubini et al., 2014). Here we explore the feasibility of a two-basket approach in the context of LCA. We extract from a LCA database several representative energy-related emissions occurring at four different locations of the world and calculate their effects on the global and regional radiative forcing and temperature change. Such results are also used to derive emission metrics such as the Global Warming Potential (GWP), Global Temperature change Potential (GTP), and Regional Temperature change Potential (RTP) and we test the performance of the metrics under a two-basket framework. Computations are performed by the Aggregated Carbon Cycle, Atmospheric Chemistry, and Climate model (ACC2) (Tanaka et al., 2013) combined with results shown in Collins et al. (2013). References Cherubini, F., T. Gasser, R. M. Bright, P. Ciais and A, H. Stromman. (2014) Linearity between temperature peak and bioenergy CO2 emission rates. Nature Climate Change, 4, 983-987. Collins, W. J., M. M. Fry, H. Yu, J. S. Fuglestvedt, D. T. Shindell and J. J. West. (2013) Global and regional temperature-change potentials for near-term climate forcers. Atmospheric Chemistry and Physics, 13, 2471-2485. Tanaka, K., D. J. A. Johansson, B. C. O'Neill, and J. S. Fuglestvedt (2013) Emission metrics under the 2°C climate stabilization target. Climatic Change, 117, 933-941.

  7. Assessment of production risks for winter wheat in different German regions under climate change conditions

    NASA Astrophysics Data System (ADS)

    Kersebaum, K. C.; Gandorfer, M.; Wegehenkel, M.

    2012-04-01

    The study shows climate change impacts on wheat production in selected regions across Germany. To estimate yield and economic effects the agro-ecosystem model HERMES was used. The model performed runs using 2 different releases of the model WETTREG providing statistically downscaled climate change scenarios for the weather station network of the German Weather Service. Simulations were done using intersected GIS information on soil types and land use identifying the most relevant sites for wheat production. The production risks for wheat yields at the middle of this century were compared to a reference of the present climate. The irrigation demand was determined by the model using an automatic irrigation mode. Production risks with and without irrigation were assessed and the economic feasibility to reduce production risks by irrigation was evaluated. Costs and benefits were compared. Additionally, environmental effects, e.g. groundwater recharge and nitrogen emissions were assessed for irrigated and rain fed systems. Results show that positive and negative effects of climate change occur within most regions depending on the site conditions. Water holding capacity and groundwater distance were the most important factors which determined the vulnerability of sites. Under climate change condition in the middle of the next century we can expect especially at sites with low water holding capacity decreasing average gross margins, higher production risks and a reduced nitrogen use efficiency under rainfed conditions. Irrigation seems to be profitable and risk reducing at those sites, provided that water for irrigation is available. Additionally, the use of irrigation can also increase nitrogen use efficiency which reduced emissions by leaching. Despite the site conditions results depend strongly on the used regional climate scenario and the model approach to consider the effect of elevated CO2 in the atmosphere.

  8. Cyclones and extreme windstorm events over Europe under climate change: Global and regional climate model diagnostics

    NASA Astrophysics Data System (ADS)

    Leckebusch, G. C.; Ulbrich, U.

    2003-04-01

    More than any changes of the climate system mean state conditions, the development of extreme events may influence social, economic and legal aspects of our society. This linkage results from the impact of extreme climate events (natural hazards) on environmental systems which again are directly linked to human activities. Prominent examples from the recent past are the record breaking rainfall amounts of August 2002 in central Europe which produced widespread floodings or the wind storm Lothar of December 1999. Within the MICE (Modelling the Impact of Climate Extremes) project framework an assessment of the impact of changes in extremes will be done. The investigation is carried out for several different impact categories as agriculture, energy use and property damage. Focus is laid on the diagnostics of GCM and RCM simulations under different climate change scenarios. In this study we concentrate on extreme windstorms and their relationship to cyclone activity in the global HADCM3 as well as in the regional HADRM3 model under two climate change scenarios (SRESA2a, B2a). In order to identify cyclones we used an objective algorithm from Murry and Simmonds which was widely tested under several different conditions. A slight increase in the occurrence of systems is identified above northern parts of central Europe for both scenarios. For more severe systems (core pressure < 990 hPa) we find an increase for western Europe. Strong wind events can be defined via different percentile values of the windspeed (e.g. above the 95 percentile). By this means the relationship between strong wind events and cyclones is also investigated. For several regions (e.g. Germany, France, Spain) a shift to more deep cyclones connected with an increasing number of strong wind events is found.

  9. Hindlimb unweighting does not alter vasoconstrictor responsiveness and nitric oxide-mediated inhibition of sympathetic vasoconstriction

    PubMed Central

    Just, Timothy P; Jendzjowsky, Nicholas G; DeLorey, Darren S

    2015-01-01

    Abstract We tested the hypothesis that physical inactivity would increase sympathetic vasoconstrictor responsiveness and diminish NO-mediated inhibition of sympathetic vasoconstriction in resting and contracting skeletal muscle. Sprague–Dawley rats (n = 33) were randomly assigned to sedentary time control (S) or hindlimb unweighted (HU) groups for 21 days. Following the intervention, rats were anaesthetized and instrumented for measurement of arterial blood pressure and femoral artery blood flow and stimulation of the lumbar sympathetic chain. The percentage change of femoral vascular conductance (%FVC) in response to sympathetic chain stimulation delivered at 2 and 5 Hz was determined at rest and during triceps surae muscle contraction before (control) and after NO synthase blockade with l-NAME (5 mg kg i.v.). Sympathetic vasoconstrictor responsiveness was not different (P > 0.05) in S and HU rats at rest (S, 2 Hz, −26 ± 8% and 5 Hz, −46 ± 12%; and HU, 2 Hz, −29 ± 9% and 5 Hz, −51 ± 10%) and during contraction (S, 2 Hz, −10 ± 7% and 5 Hz, −23 ± 11%; and HU, 2 Hz, −9 ± 5% and 5 Hz, −22 ± 7%). Nitric oxide synthase blockade caused a similar increase (P > 0.05) in sympathetic vasoconstrictor responsiveness in HU and S rats at rest (S, 2 Hz, −41 ± 7% and 5 Hz, −58 ± 8%; and HU, 2 Hz, −43 ± 6% and 5 Hz, −63 ± 8%) and during muscle contraction (S, 2 Hz, −15 ± 6% and 5 Hz, −31 ± 11%; and HU, 2 Hz, −12 ± 5% and 5 Hz, −29 ± 8%). Skeletal muscle NO synthase expression and ACh-mediated vasodilatation were also not different between HU and S rats. These data suggest that HU does not alter sympathetic vasoconstrictor responsiveness and NO-mediated inhibition of sympathetic vasoconstriction in resting and contracting skeletal muscle. Key points Physical inactivity increases the risk of cardiovascular disease and may alter sympathetic nervous system control of vascular

  10. A sharp Moho step under Central and Eastern Betics, Western Mediterranean region

    NASA Astrophysics Data System (ADS)

    de Lis Mancilla, Flor; Aguilera-Molina, Antonio; Heit, Benjamin; Morales, Jose; Yuan, Xiaohui; Stich, Daniel; Martin, Rosa

    2016-04-01

    Previous geophysical studies in the northern limit of the western Mediterranean region have showed that the Iberian crust understrusts the Alboran domain under its contact with the External zones. They observe the presence of slab-type feature of Iberian lithosphere at the western Betics and interpret tearing and delamination of this Iberian slab at central and eastern Betics. To map the variations of the lithospheric structure between the different geological domains under central and eastern Betics, we deploy two dense seismic profiles (~120 and ~160 km length). The spacing between stations, around 2-3 km, allows mapping with high accuracy variations of the crustal structure. By interpreting P-receiver functions, we observe sharp Moho steps of ~15-17 km underneath the Internal zones (Alboran domain) at both profiles. The images suggest that the Iberian crust undertrusts the more deformed Alboran crust and terminates sharply under the contact between the Alpujarride and the Nevado-Filabre complexes (Alboran domain). The thickness of the Iberian crust near the edge, ~17 km, and its position along the contact suggest that the breaking of the Iberian slab occurs in the transitional crust of the Iberian Paleomargin.

  11. Oscillatory dynamics of vasoconstriction and vasodilation identified by time-localized phase coherence

    NASA Astrophysics Data System (ADS)

    Sheppard, L. W.; Vuksanović, V.; McClintock, P. V. E.; Stefanovska, A.

    2011-06-01

    We apply wavelet-based time-localized phase coherence to investigate the relationship between blood flow and skin temperature, and between blood flow and instantaneous heart rate (IHR), during vasoconstriction and vasodilation provoked by local cooling or heating of the skin. A temperature-controlled metal plate (≈10 cm2) placed on the volar side of the left arm was used to provide the heating and cooling. Beneath the plate, the blood flow was measured by laser Doppler flowmetry and the adjacent skin temperature by a thermistor. Two 1 h datasets were collected from each of the ten subjects. In each case a 30 min basal recording was followed by a step change in plate temperature, to either 24 °C or 42 °C. The IHR was derived from simultaneously recorded ECG. We confirm the changes in the energy and frequency of blood flow oscillations during cooling and heating reported earlier. That is, during cooling, there was a significant decrease in the average frequency of myogenic blood flow oscillations (p < 0.05) and the myogenic spectral peak became more prominent. During heating, there was a significant (p < 0.05) general increase in spectral energy, associated with vasodilation, except in the myogenic interval. Weak phase coherence between temperature and blood flow was observed for unperturbed skin, but it increased in all frequency intervals as a result of heating. It was not significantly affected by cooling. We also show that significant (p < 0.05) phase coherence exists between blood flow and IHR in the respiratory and myogenic frequency intervals. Cooling did not affect this phase coherence in any of the frequency intervals, whereas heating enhanced the phase coherence in the respiratory and myogenic intervals. This can be explained by the reduction in vascular resistance produced by heating, a process where myogenic mechanisms play a key role. We conclude that the mechanisms of vasodilation and vasoconstriction, in response to temperature change, are

  12. Oscillatory dynamics of vasoconstriction and vasodilation identified by time-localized phase coherence.

    PubMed

    Sheppard, L W; Vuksanović, V; McClintock, P V E; Stefanovska, A

    2011-06-21

    We apply wavelet-based time-localized phase coherence to investigate the relationship between blood flow and skin temperature, and between blood flow and instantaneous heart rate (IHR), during vasoconstriction and vasodilation provoked by local cooling or heating of the skin. A temperature-controlled metal plate (approximately 10 cm2) placed on the volar side of the left arm was used to provide the heating and cooling. Beneath the plate, the blood flow was measured by laser Doppler flowmetry and the adjacent skin temperature by a thermistor. Two 1 h datasets were collected from each of the ten subjects. In each case a 30 min basal recording was followed by a step change in plate temperature, to either 24 °C or 42 °C. The IHR was derived from simultaneously recorded ECG. We confirm the changes in the energy and frequency of blood flow oscillations during cooling and heating reported earlier. That is, during cooling, there was a significant decrease in the average frequency of myogenic blood flow oscillations (p < 0.05) and the myogenic spectral peak became more prominent. During heating, there was a significant (p < 0.05) general increase in spectral energy, associated with vasodilation, except in the myogenic interval. Weak phase coherence between temperature and blood flow was observed for unperturbed skin, but it increased in all frequency intervals as a result of heating. It was not significantly affected by cooling. We also show that significant (p < 0.05) phase coherence exists between blood flow and IHR in the respiratory and myogenic frequency intervals. Cooling did not affect this phase coherence in any of the frequency intervals, whereas heating enhanced the phase coherence in the respiratory and myogenic intervals. This can be explained by the reduction in vascular resistance produced by heating, a process where myogenic mechanisms play a key role. We conclude that the mechanisms of vasodilation and vasoconstriction, in response to temperature change

  13. Assessing Regional Scale Variability in Extreme Value Statistics Under Altered Climate Scenarios

    SciTech Connect

    Brunsell, Nathaniel; Mechem, David; Ma, Chunsheng

    2015-02-20

    validity of an innovative multi–resolution information theory approach, and the ability of the RCM modeling framework to represent the low-frequency modulation of extreme climate events. Once the skill of the modeling and analysis methodology has been established, we will apply the same approach for the AR5 (IPCC Fifth Assessment Report) climate change scenarios in order to assess how climate extremes and the the influence of lowfrequency variability on climate extremes might vary under changing climate. The research specifically addresses the DOE focus area 2. Simulation of climate extremes under a changing climate. Specific results will include (1) a better understanding of the spatial and temporal structure of extreme events, (2) a thorough quantification of how extreme values are impacted by low-frequency climate teleconnections, (3) increased knowledge of current regional climate models ability to ascertain these influences, and (4) a detailed examination of the how the distribution of extreme events are likely to change under different climate change scenarios. In addition, this research will assess the ability of the innovative wavelet information theory approach to characterize extreme events. Any and all of these results will greatly enhance society’s ability to understand and mitigate the regional ramifications of future global climate change.

  14. Winter climate changes over East Asian region under RCP scenarios using East Asian winter monsoon indices

    NASA Astrophysics Data System (ADS)

    Hong, Ja-Young; Ahn, Joong-Bae; Jhun, Jong-Ghap

    2016-03-01

    The changes in the winter climatology and variability of the East Asian winter monsoon (EAWM) for the late 21st century (2070-2099) under the Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios are projected in terms of EAWM indices (EAWMIs). Firstly, the capability of the climate models participating in the Coupled Model Intercomparison Project phase 5 (CMIP5) in simulating the boreal winter climatology and the interannual variability of the EAWM for the late 20th century (1971-2000) is examined. Nine of twenty-three climate models are selected based on the pattern correlations with observation and a multi-model ensemble is applied to the nine model data. Three of twelve EAWMIs that show the most significant temporal correlations between the observation and CMIP5 surface air temperatures are utilized. The ensemble CMIP5 is capable of reproducing the overall features of the EAWM in spite of some biases in the region. The negative correlations between the EAWMIs and boreal winter temperature are well reproduced and 3-5 years of the major interannual variation observed in this region are also well simulated according to power spectral analyses of the simulated indices. The fields regressed onto the indices that resemble the composite strong winter monsoon pattern are simulated more or less weakly in CMIP5 compared to the observation. However, the regressed fields of sea level pressure, surface air temperature, 500-hPa geopotential height, and 300-hPa zonal wind are well established with pattern correlations above 0.83 between CMIP5 and observation data. The differences between RCPs and Historical indicate strong warming, which increases with latitude, ranging from 1 to 5 °C under RCP4.5 and from 3 to 7 °C under RCP8.5 in the East Asian region. The anomalous southerly winds generally become stronger, implying weaker EAWMs in both scenarios. These features are also identified with fields regressed onto the indices in RCPs. The future projections reveal

  15. Coastal erosion impacts under climate change scenarios at the regional scale in the North Adriatic Sea

    NASA Astrophysics Data System (ADS)

    Critto, A.; Gallina, V.; Torresan, S.; Rizzi, J.; Zabeo, A.; Carniel, S.; Sclavo, M.; Marcomini, A.

    2012-04-01

    Global climate change is likely to pose additional pressures on coastal ecosystems by accelerating sea level rise, storms, flooding and erosion. Specifically, coastal erosion is an issue of major concern for estuarine and deltaic coastal areas and ecosystems and it is expected to increase in size and magnitude due to climate change forcing. Accordingly, the use of climate change scenarios in the assessment of coastal erosion risks could improve the development of sustainable adaptation strategies. In order to analyze the potential consequences of climate change on coastal erosion processes and evaluate the related impacts on coastal receptors (i.e. beaches, river mouths, wetlands and protected areas), a Regional Risk Assessment (RRA) methodology was developed and applied to the North Adriatic coast (Italy). Climate induced hazards were analyzed by means of regional hydrodynamic models that provide information about the main coastal erosion stressors (i.e. increases in mean sea-level, changes in wave height and variations in the extent of sediments deposition at the sea bottom) under climate change scenarios (i.e. regional climate projections). Site-specific environmental and socio-economic indicators (e.g. vegetation cover, geomorphology, sediment budget, protection level, population density and wetland extension) and hazard metrics were aggregated in the RRA methodology in order to develop exposure, susceptibility, risk and damage maps that identify and prioritize hot-spot areas and vulnerable targets at the regional scale. Future seasonal exposure maps of coastal erosion at the regional scale depict a worse situation in winter and autumn for the future period 2070-2100 and highlight hot-spot exposure areas surrounding the Po River Delta. Moreover, risk maps highlighted that the receptors (i.e. exposure units) at higher risk to coastal erosion are beaches, wetlands and river mouths with relevant percentages of the territory characterized by higher risk scores

  16. Jael syndrome: removal of a knife blade impacted in the maxillofacial region under local anaesthesia

    PubMed Central

    Dominguete, Paulo Roberto; Matos, Bruno Figueiredo; Meyer, Tufi Neder; Oliveira, Lucinei Roberto

    2013-01-01

    The presence of retained foreign bodies in the maxillofacial region as a consequence of penetrating injuries from knives is poorly documented in the scientific literature. This manuscript reports the case of a 30-year-old Caucasian with a knife blade lodged in the maxillofacial skeleton. Following clinical and radiographic exams, it was determined that the object had penetrated through the left nostril and nasal septum, in the direction of the right maxillary sinus, and remained impacted without causing injury to important anatomical structures. After systemic assessment and determination of the exact location of the knife blade, the object was removed in an outpatient setting under local anaesthesia. This manuscript aims to report a rare case of a transfacial penetrating injury involving a knife blade that was removed in an outpatient setting while also discussing the proper conduct and treatment options for similar cases in the context of a brief literature review. PMID:23580680

  17. Volume thermal expansivity for lower mantle region of earth under adiabatic condition

    NASA Astrophysics Data System (ADS)

    Sharma, S. K.

    2013-06-01

    A reciprocal equation for the volume dependence of Anderson-Grüneisen parameter has been proposed. This equation has been found to fit the seismic data for the lower mantle region of the Earth. We have developed a new expression for predicting the values of density (volume) dependence of volume thermal expansivity under adiabatic conditions based on the reciprocal equation for the volume dependence of Anderson-Grüneisen parameter. It is found that our relationship fits well the seismic data on volume thermal expansivity for lower mantle corresponding to a wide range of pressures (0-135.75 GPa). These equations thus proposed are found to be consistent with the thermodynamic constraints.

  18. Folic Acid Improves Acetylcholine-induced Vasoconstriction of Coronary Vessels Isolated from hyperhomocysteinemic mice: An Implication to Coronary Vasospasm*

    PubMed Central

    Qipshidze, Natia; Metreveli, Naira; Lominadze, David; Tyagi, Suresh C.

    2011-01-01

    Human atherosclerotic coronary vessels elicited vasoconstriction to acetylcholine (Ach) and revealed a phenomenon of vasospasm. Homocysteine (Hcy) levels are elevated in the atherosclerotic plaque tissue, suggesting its pathological role in endothelial damage in atherosclerotic diseases. Accordingly, we examined the role hyperhomocysteinemia (HHcy) in coronary endothelial dysfunction, vessel wall thickness, lumen narrowing, leading to acute/chronic coronary vasospasm. The therapeutic potential and mechanisms of folic acid using hyperhomocysteinemic cystathionine beta synthase heterozygote (CBS-/+) and wild type (CBS+/+) mice were addressed. The CBS-/+ and CBS+/+ mice were treated with or without a Hcy lowering agent folic acid (FA) in drinking water (0.03 g/L) for 4 weeks. The isolated mouse septum coronary artery was cannulated and pressurized at 60 mmHg. The wall thickness and lumen diameters were measured by Ion-Optic. The vessels were treated with Ach (10-8-10-5 M) and, for comparison, with nonendothelial vasodilator sodium nitroprusside (10-5 M).The endothelium-impaired arteries from CBC-/+ mice constricted in response to Ach and this vasoconstriction was mitigated with FA supplementation. The level of endothelial nitric oxide synthase (eNOS) was lower in coronary artery in CBS-/+ than of CBS+/+ mice. Treatment with FA increased the levels of Ach-induced NO generation in the coronary artery of CBS-/+ mice. The results suggest that Ach induced coronary vasoconstriction in CBS-/+ mice and this vasoconstriction was ameliorated by folic acid treatment. The mechanisms for the impairment of vascular function and therapeutic effects of folic acid may be related to the regulation of eNOS expression, NO availability and tissue homocysteine. PMID:21792928

  19. Tetramethylpyrazine, a Chinese drug, blocks coronary vasoconstriction by endothelin-1 and decreases plasma endothelin-1 levels in experimental animals.

    PubMed

    Zeng, Z; Zhu, W; Zhou, X; Jin, Z; Liu, H; Chen, X; Pan, J; Demura, H; Naruse, M; Shi, Y

    1998-01-01

    The purpose of this study was to investigate effects of tetramethylpyrazine (TMP), a Chinese plant-derived medicine, on coronary vasoconstriction and related electrocardiographic and histologic changes caused by endothelin-1 (ET-1), and on plasma ET-1 levels. ET-1 (75 pmol) was administered into the left coronary artery (LCA) in anesthetized closed-chest dogs with and without prior infusion of TMP (80 mg/kg). Coronary arterial diameter (CAD) was determined by coronary arteriography (CAG). Blood pressure and electrocardiogram (ECG) were monitored continuously. Histologic damage in tissues was ascertained microscopically. Plasma ET-1 and 6-keto-PGF1 levels were determined by RIA 90 min after i.v. injection of TMP (25 mg/kg; n = 5) in rabbits. Intracoronary injection of ET-1 resulted in a significant vasoconstriction of the entire vascular bed of the LCA, with a decrease in CAD of 35.9 +/- 5.7% (n = 5; p < 0.01) and ischemic changes on ECG and in tissues of endocardium, myocardium, coronary endothelial cells, and capillary vessels. Pretreatment with TMP produced a significant increase in CAD by 38.5 +/- 7.8% (n = 5; p < 0.01) and greatly suppressed the vasoconstriction produced by ET-1. The myocardial tissue damage estimated from the ratio of ischemic area for the entire area after ET-1 injection (35.6%) was completely abolished by TMP (0.6%). In addition, TMP injection induced a significant decrease in plasma ET-1 levels and an increase in 6-keto-PGF1 levels in rabbits. The Chinese medicine TMP could be a useful therapeutic agent in ischemic heart disease by suppressing coronary vasoconstriction and ischemic changes in the tissues produced by ET-1. PMID:9595468

  20. Endothelial dysfunction enhances vasoconstriction due to scavenging of nitric oxide by a hemoglobin-based oxygen carrier

    PubMed Central

    Yu, Binglan; Shahid, Mohd; Egorina, Elena M.; Sovershaev, Mikhail A.; Raher, Michael J.; Lei, Chong; Wu, Mei X.; Bloch, Kenneth D.; Zapol, Warren M.

    2010-01-01

    Background At present, there is no safe and effective hemoglobin-based oxygen carrier (HBOC) to substitute for red blood cell transfusion. It is uncertain whether a deficiency of endothelial nitric oxide bioavailability (endothelial dysfunction) prevents or augments the HBOC-induced vasoconstriction. Methods Hemodynamic effects of infusion of PolyHeme (1.08 g hemoglobin/kg, Northfield Laboratories, Evanston, IL) or murine tetrameric hemoglobin (0.48 g hemoglobin/kg) were determined in awake healthy lambs, awake mice and anesthetized mice. In vitro, a cumulative dose-tension response was obtained by sequential addition of PolyHeme or tetrameric hemoglobin to phenylephrine-precontracted murine aortic rings. Results Infusion of PolyHeme did not cause systemic hypertension in awake lambs, but produced acute systemic and pulmonary vasoconstriction. Infusion of PolyHeme did not cause systemic hypertension in healthy wild-type mice, but induced severe systemic vasoconstriction in mice with endothelial dysfunction (either db/db mice or high-fat fed wild-type mice for 4–6 weeks). The db/db mice were more sensitive to systemic vasoconstriction than wild-type mice after the infusion of either tetrameric hemoglobin or PolyHeme. Murine aortic ring studies confirmed that db/db mice have an impaired response to an endothelial-dependent vasodilator and an enhanced vasoconstrictor response to a HBOC. Conclusions Reduction of low molecular weight hemoglobin concentrations to less than 1% is insufficient to abrogate the vasoconstrictor effects of HBOC infusion in healthy awake sheep or in mice with reduced vascular nitric oxide levels associated with endothelial dysfunction. These findings suggest that testing HBOCs in animals with endothelial dysfunction can provide a more sensitive indication of their potential vasoconstrictor effects. PMID:20179495

  1. Demographically-Based Evaluation of Genomic Regions under Selection in Domestic Dogs.

    PubMed

    Freedman, Adam H; Schweizer, Rena M; Ortega-Del Vecchyo, Diego; Han, Eunjung; Davis, Brian W; Gronau, Ilan; Silva, Pedro M; Galaverni, Marco; Fan, Zhenxin; Marx, Peter; Lorente-Galdos, Belen; Ramirez, Oscar; Hormozdiari, Farhad; Alkan, Can; Vilà, Carles; Squire, Kevin; Geffen, Eli; Kusak, Josip; Boyko, Adam R; Parker, Heidi G; Lee, Clarence; Tadigotla, Vasisht; Siepel, Adam; Bustamante, Carlos D; Harkins, Timothy T; Nelson, Stanley F; Marques-Bonet, Tomas; Ostrander, Elaine A; Wayne, Robert K; Novembre, John

    2016-03-01

    Controlling for background demographic effects is important for accurately identifying loci that have recently undergone positive selection. To date, the effects of demography have not yet been explicitly considered when identifying loci under selection during dog domestication. To investigate positive selection on the dog lineage early in the domestication, we examined patterns of polymorphism in six canid genomes that were previously used to infer a demographic model of dog domestication. Using an inferred demographic model, we computed false discovery rates (FDR) and identified 349 outlier regions consistent with positive selection at a low FDR. The signals in the top 100 regions were frequently centered on candidate genes related to brain function and behavior, including LHFPL3, CADM2, GRIK3, SH3GL2, MBP, PDE7B, NTAN1, and GLRA1. These regions contained significant enrichments in behavioral ontology categories. The 3rd top hit, CCRN4L, plays a major role in lipid metabolism, that is supported by additional metabolism related candidates revealed in our scan, including SCP2D1 and PDXC1. Comparing our method to an empirical outlier approach that does not directly account for demography, we found only modest overlaps between the two methods, with 60% of empirical outliers having no overlap with our demography-based outlier detection approach. Demography-aware approaches have lower-rates of false discovery. Our top candidates for selection, in addition to expanding the set of neurobehavioral candidate genes, include genes related to lipid metabolism, suggesting a dietary target of selection that was important during the period when proto-dogs hunted and fed alongside hunter-gatherers. PMID:26943675

  2. Demographically-Based Evaluation of Genomic Regions under Selection in Domestic Dogs

    PubMed Central

    Freedman, Adam H.; Schweizer, Rena M.; Ortega-Del Vecchyo, Diego; Han, Eunjung; Davis, Brian W.; Gronau, Ilan; Silva, Pedro M.; Galaverni, Marco; Fan, Zhenxin; Marx, Peter; Lorente-Galdos, Belen; Ramirez, Oscar; Hormozdiari, Farhad; Alkan, Can; Vilà, Carles; Squire, Kevin; Geffen, Eli; Kusak, Josip; Boyko, Adam R.; Parker, Heidi G.; Lee, Clarence; Tadigotla, Vasisht; Siepel, Adam; Bustamante, Carlos D.; Harkins, Timothy T.; Nelson, Stanley F.; Marques-Bonet, Tomas; Ostrander, Elaine A.; Wayne, Robert K.; Novembre, John

    2016-01-01

    Controlling for background demographic effects is important for accurately identifying loci that have recently undergone positive selection. To date, the effects of demography have not yet been explicitly considered when identifying loci under selection during dog domestication. To investigate positive selection on the dog lineage early in the domestication, we examined patterns of polymorphism in six canid genomes that were previously used to infer a demographic model of dog domestication. Using an inferred demographic model, we computed false discovery rates (FDR) and identified 349 outlier regions consistent with positive selection at a low FDR. The signals in the top 100 regions were frequently centered on candidate genes related to brain function and behavior, including LHFPL3, CADM2, GRIK3, SH3GL2, MBP, PDE7B, NTAN1, and GLRA1. These regions contained significant enrichments in behavioral ontology categories. The 3rd top hit, CCRN4L, plays a major role in lipid metabolism, that is supported by additional metabolism related candidates revealed in our scan, including SCP2D1 and PDXC1. Comparing our method to an empirical outlier approach that does not directly account for demography, we found only modest overlaps between the two methods, with 60% of empirical outliers having no overlap with our demography-based outlier detection approach. Demography-aware approaches have lower-rates of false discovery. Our top candidates for selection, in addition to expanding the set of neurobehavioral candidate genes, include genes related to lipid metabolism, suggesting a dietary target of selection that was important during the period when proto-dogs hunted and fed alongside hunter-gatherers. PMID:26943675

  3. Organochlorine pesticides in soils under different land usage in the Taihu Lake region, China.

    PubMed

    Wang, Fang; Jiang, Xin; Bian, Yong-Rong; Yao, Fen-Xia; Gao, Hong-Jian; Yu, Gui-Fen; Munch, Jean Charles; Schroll, Reiner

    2007-01-01

    A field study was conducted in the Taihu Lake region, China in 2004 to reveal the organochlorine pesticide concentrations in soils after the ban of these substances in the year 1983. Thirteen organochlorine pesticides (OCPs) were analyzed in soils from paddy field, tree land and fallow land. Total organochlorine pesticide residues were higher in agricultural soils than in uncultivated fallow land soils. Among all the pesticides, sigmaDDX (DDD, DDE and DDT) had the highest concentration for all the soil samples, ranging from 3.10 ng/g to 166.55 ng/g with a mean value of 57.04 ng/g and followed by sigmaHCH, ranging from 0.73 ng/g to 60.97 ng/g with a mean value of 24.06 ng/g. Dieldrin, endrin, HCB and alpha-endosulfan were also found in soils with less than 15 ng/g. Ratios of p,p'-(DDD+DDE)/DDT in soils under three land usages were: paddy field > tree land > fallow land, indicating that land usage influenced the degradation of DDT in soils. Ratios of p,p'-(DDD+DDE)/DDT > 1, showing aged residues of DDTs in soils of the Taihu Lake region. The results were discussed with data from a former study that showed very low actual concentrations of HCH and DDT in soils in the Taihu Lake region, but according to the chemical half-lives and their concentrations in soils in 1980s, the concentration of DDT in soils seemed to be underestimated. In any case our data show that the ban on the use of HCH and DDT resulted in a tremendous reduction of these pesticide residues in soils, but there are still high amounts of pesticide residues in soils, which need more remediation processes. PMID:17915688

  4. Diagnosing RCVS Without the CV: The Evolution of Reversible Cerebral Vasoconstriction Syndrome.

    PubMed

    Jacoby, Nuri; Kaunzner, Ulrike; Dinkin, Marc; Safdieh, Joseph

    2016-07-01

    This is a case of a 52-year-old man with a past medical history of 2 episodes of coital thunderclap headaches as well as recent cocaine, marijuana, and pseudoephedrine use, who presented with sudden, sharp, posterior headache associated with photophobia and phonophobia. His initial magnetic resonance imaging (MRI) of the brain, magnetic resonance angiography (MRA) of the head, and magnetic resonance venography (MRV) of the head were all normal as well as a normal lumbar puncture. Given the multiple risk factors for reversible cerebral vasoconstriction syndrome (RCVS), the patient was treated for suspected RCVS, despite the normal imaging. Repeat MRI brain 3 days after hospital admission demonstrated confluent white matter T2 hyperintensities most prominent in the occipital lobes, typical of posterior reversible encephalopathy syndrome (PRES). Repeat MRA of the head 1 day after discharge and 4 days after the abnormal MRI brain showed multisegment narrowing of multiple arteries. This case demonstrates that RCVS may present with PRES on MRI brain and also exemplifies the need to treat suspected RCVS even if imaging is normal, as abnormalities in both the MRI and the MRA may be delayed. PMID:27366300

  5. The effects of oxygen induced pulmonary vasoconstriction on bedside measurement of pulmonary gas exchange.

    PubMed

    Weinreich, Ulla M; Thomsen, Lars P; Rees, Stephen E; Rasmussen, Bodil S

    2016-04-01

    In patients with respiratory failure measurements of pulmonary gas exchange are of importance. The bedside automatic lung parameter estimator (ALPE) of pulmonary gas exchange is based on changes in inspired oxygen (FiO2) assuming that these changes do not affect pulmonary circulation. This assumption is investigated in this study. Forty-two out of 65 patients undergoing coronary artery bypass grafting (CABG) had measurements of mean pulmonary arterial pressure (MPAP), cardiac output and pulmonary capillary wedge pressure thus enabling the calculation of pulmonary vascular resistance (PVR) at each FiO2 level. The research version of ALPE was used and FiO2 was step-wise reduced a median of 0.20 and ultimately returned towards baseline values, allowing 6-8 min' steady state period at each of 4-6 levels before recording the oxygen saturation (SpO2). FiO2 reduction led to median decrease in SpO2 from 99 to 92 %, an increase in MPAP of 4 mmHg and an increase in PVR of 36 dyn s cm(-5). Changes were immediately reversed on returning FiO2 towards baseline. In this study changes in MPAP and PVR are small and immediately reversible consistent with small changes in pulmonary gas exchange. This indicates that mild deoxygenation induced pulmonary vasoconstriction does not have significant influences on the ALPE parameters in patients after CABG. PMID:25962614

  6. Experimental Gestational Diabetes Mellitus Induces Blunted Vasoconstriction and Functional Changes in the Rat Aorta

    PubMed Central

    Tufiño, Cecilia; Villanueva-López, Cleva; Ibarra-Barajas, Maximiliano; Bracho-Valdés, Ismael; Bobadilla-Lugo, Rosa Amalia

    2014-01-01

    Diabetic conditions increase vascular reactivity to angiotensin II in several studies but there are scarce reports on cardiovascular effects of hypercaloric diet (HD) induced gestational diabetes mellitus (GDM), so the objective of this work was to determine the effects of HD induced GDM on vascular responses. Angiotensin II as well as phenylephrine induced vascular contraction was tested in isolated aorta rings with and without endothelium from rats fed for 7 weeks (4 before and 3 weeks during pregnancy) with standard (SD) or hypercaloric (HD) diet. Also, protein expression of AT1R, AT2R, COX-1, COX-2, NOS-1, and NOS-3 and plasma glucose, insulin, and angiotensin II levels were measured. GDM impaired vasoconstrictor response (P < 0.05 versus SD) in intact (e+) but not in endothelium-free (e−) vessels. Losartan reduced GDM but not SD e− vasoconstriction (P < 0.01 versus SD). AT1R, AT2R, and COX-1 and COX-2 protein expression were significantly increased in GDM vessels (P < 0.05 versus SD). Results suggest an increased participation of endothelium vasodilator mediators, probably prostaglandins, as well as of AT2 vasodilator receptors as a compensatory mechanism for vasoconstrictor changes generated by experimental GDM. Considering the short term of rat pregnancy findings can reflect early stage GDM adaptations. PMID:25610861

  7. Cyclooxygenase blockade (COB) attenuates ethanol-induced pulmonary vasoconstriction in perfused rat lungs

    SciTech Connect

    Drummond, W.H.; Lyles, D. )

    1990-02-26

    Ethanol causes pulmonary vasoconstriction and vascular leak by obscure mechanisms. In lambs, COB with indomethacin (Indo) or meclofenamate (Meclo) block ethanol's circulatory effects. To test for these effects in rats, in-situ, ventilated, Krebs-Henselheit perfused (constant flow) lungs were studied in 6 groups: ethanol (ETOH) and perfusate controls; ETOH/Meclo, 0.5 and 1 mg/kg, IV; ETOH/Indo, 0.5 and 1 mg/kg, IV, given 30 minutes before study. They measured mean pulmonary arterial pressure (PAP), peak inspiratory pressure (PIP) and edema, indexed by reservoir weight change (RW), then by tracheal froth ( death'). ETOH doses (0.5, 1.3 and 2.2gm) were infused into the perfusate (60 ml). Data were analyzed by ANOVA and X{sup 2}; n = 9 in each group. PAP differed by treatment, by drug/dose, and by dose/treatment interactions; PIP, RW change, and death' were attenuated. Data show that COB lessens the vascular and edema effects of moderate dose ETOH, which larger ETOH doses override.

  8. Modelling Sub-canopy Shortwave Under Needle-Leaf Forests in Mountain Regions

    NASA Astrophysics Data System (ADS)

    Ellis, C.; Pomeroy, J. W.

    2006-12-01

    Snowmelt is one of the most important hydrological events in mountain regions, responsible for soil moisture recharge, vegetation growth, and ecosystem productivity. Mountain snowmelt is also of tremendous importance to the downstream water resource of many North American regions, from where over 80% of river- flows may originate. As mountain regions are covered largely by needle-leaf forests, turbulent energy exchanges are suppressed and snowmelt is driven primarily by shortwave irradiance energy transmitted to the sub-canopy Thus, effective prediction of the timing and magnitude of mountain snowmelt runoff for the purposes reservoir operation, land-use planning, and flood forecasting require accurate estimation of shortwave irradiance transmission through sloping forest-cover. This paper outlines and evaluates a physically-based model requiring minimal calibration designed to estimate shortwave irradiance transmission through needle-leaf forest cover with respect to surface orientation. Transmission was estimated using forest-survey data to calculate the fractions of forest occupied by non-transmitting trunks, partially-transmitting crowns and fully-transmitting gaps with respect to both above-canopy diffuse and beam irradiance. Simulations were conducted for continuous and uniform lodgepole pine forests on level and north-facing slopes and a discontinuous, non-uniform forest on a southeast-facing slope during snowmelt at the Marmot Creek Research Basin, Alberta, Canada. Mean observed daily transmissivity values were 0.09 at the north-facing forest, 0.21 at the level forest and 0.36 at the southeast-facing forest. Modelled and observed results indicate that sub-canopy shortwave irradiance snowmelt energy exhibited greatest variation with change in sky condition and forest-cover density under south-facing forests and the least variation under north-facing forests. This suggests the timing and rate of snowmelt may vary more for south-facing forests than for forests

  9. Molecular mapping of genomic regions underlying barley yellow dwarf tolerance in cultivated oat (Avena sativa L.).

    PubMed

    Zhu, S; Kolb, F L; Kaeppler, H F

    2003-05-01

    Barley yellow dwarf (BYD) is one of the most important viral diseases in small grains, including oat (Avena sativa L.). Breeding for BYD tolerance is an effective and efficient means to control the disease. Characterization of major sources of tolerance, and identification of marker and the trait associations, will directly benefit breeding for BYD tolerance. Genomic regions underlying BYD tolerance were mapped and characterized in an oat population consisting of 152 recombinant inbred lines from the cross of 'Ogle' (tolerant)/MAM17-5 (sensitive). Tolerance was evaluated in replicated field trials across 2 years under artificial inoculation with viruliferous aphids harboring BYD virus isolate PAV-IL. Composite interval mapping was used for quantitative trait loci (QTLs) analysis with a framework map consisting of 272 molecular markers. Four QTLs, BYDq1, BYDq2, BYDq3 and BYDq4, for BYD tolerance were identified on linkage groups OM1, 5, 7 and 24, respectively. All but BYDq2 were consistently detected across both years. Significant epistasis was found between some QTLs. The final model including the epistatic effect explained 50.3 to 58.2% of the total phenotypic variation for BYD tolerance. Some QTLs for BYD tolerance were closely linked to QTLs for plant height and days to heading. Potential problems with QTL mapping for BYD tolerance have been discussed. The identified association of markers and tolerance should be useful to pyramid favorable alleles for BYD tolerance into individual oat lines. PMID:12748782

  10. Study of aerosol radiative properties under different relative humidity conditions in the thermal infrared region

    NASA Astrophysics Data System (ADS)

    Kuo, C. P.; Yang, P.; Nasiri, S. L.; Liu, X.

    2014-12-01

    In the aerosol transport process, the optical properties of aerosol particles can vary due to humidification or mixing with other kinds of aerosols. Previous studies have shown mixing dust with other types of aerosol tends to make the aerosol more spectrally absorptive, but the degree of impact of relative humidity (RH) along the transport path is not clear. To investigate this effect, we conduct a numerical study to estimate the radiative sensitivity of aerosols under various relative humidity conditions. Specifically, the OPAC (Optical Properties of Aerosols and Clouds) database is used, which provides the optical properties (i.e., the extinction, scattering and absorption coefficient, single-scattering albedo, asymmetry factor and phase function) of ten types of aerosols under various relative humidity conditions. Lookup tables (LUTs) of the bidirectional reflectivity, transmissivity and effective emissivity will be computed for the ten aerosol types for input to the high-spectral-resolution radiative transfer model (HRTM). Using these LUTs, the HTRM can calculate top-of-atmospheric brightness temperatures, which we can use to determine the degree of radiative sensitivity in the infrared spectral region. Furthermore, comparisons between simulations and MODIS observations will be presented.

  11. 5'-Untranslated region of heat shock protein 70 mRNA drives translation under hypertonic conditions.

    PubMed

    Rocchi, Laura; Alfieri, Roberta R; Petronini, Pier Giorgio; Montanaro, Lorenzo; Brigotti, Maurizio

    2013-02-01

    In mammalian cells, adaptation to hypertonic conditions leads to the activation of an array of early (cell shrinkage, regulatory volume increase) and late (accumulation of compatible osmolytes) responses and increased level of HSPs (heat shock proteins). Protein synthesis is strongly inhibited few minutes after the hypertonic challenge as demonstrated in whole cells and as reproduced under controlled conditions in cell-free systems. Different mechanisms known to mediate the accumulation of HSP70, such as mRNA transcription and stabilization, require fully active protein synthesis. We show that the 5'-untranslated region of HSP70 messenger drives a hypertonicity-resistant translation (up to 0.425 osmol/kg of water), whereas cap-dependent protein synthesis is almost totally blocked under the same conditions. The results, obtained in cell-free systems and in whole cells, might help to explain why HSP70 is accumulated in cells when total protein synthesis is impaired. We also observed that translation initiated by viral IRES (from Cricket paralysis virus) is highly efficient in cells exposed to hyperosmolarity, suggesting that the resistance to hypertonic conditions is a more general feature of cap-independent translation. The described mechanism may also play a role in the control of translation of other messengers encoding for proteins involved in the adaptation to hypertonicity. PMID:23291172

  12. Regional Flood Frequency Analysis using Support Vector Regression under historical and future climate

    NASA Astrophysics Data System (ADS)

    Gizaw, Mesgana Seyoum; Gan, Thian Yew

    2016-07-01

    Regional Flood Frequency Analysis (RFFA) is a statistical method widely used to estimate flood quantiles of catchments with limited streamflow data. In addition, to estimate the flood quantile of ungauged sites, there could be only a limited number of stations with complete dataset are available from hydrologically similar, surrounding catchments. Besides traditional regression based RFFA methods, recent applications of machine learning algorithms such as the artificial neural network (ANN) have shown encouraging results in regional flood quantile estimations. Another novel machine learning technique that is becoming widely applicable in the hydrologic community is the Support Vector Regression (SVR). In this study, an RFFA model based on SVR was developed to estimate regional flood quantiles for two study areas, one with 26 catchments located in southeastern British Columbia (BC) and another with 23 catchments located in southern Ontario (ON), Canada. The SVR-RFFA model for both study sites was developed from 13 sets of physiographic and climatic predictors for the historical period. The Ef (Nash Sutcliffe coefficient) and R2 of the SVR-RFFA model was about 0.7 when estimating flood quantiles of 10, 25, 50 and 100 year return periods which indicate satisfactory model performance in both study areas. In addition, the SVR-RFFA model also performed well based on other goodness-of-fit statistics such as BIAS (mean bias) and BIASr (relative BIAS). If the amount of data available for training RFFA models is limited, the SVR-RFFA model was found to perform better than an ANN based RFFA model, and with significantly lower median CV (coefficient of variation) of the estimated flood quantiles. The SVR-RFFA model was then used to project changes in flood quantiles over the two study areas under the impact of climate change using the RCP4.5 and RCP8.5 climate projections of five Coupled Model Intercomparison Project (CMIP5) GCMs (Global Climate Models) for the 2041

  13. 20 CFR 661.290 - Under what circumstances may States require Local Boards to take part in regional planning...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... activities? (a) The State may require Local Boards within a designated region (as defined at 20 CFR 660.300... 20 Employees' Benefits 4 2014-04-01 2014-04-01 false Under what circumstances may States require Local Boards to take part in regional planning activities? 661.290 Section 661.290 Employees'...

  14. Role of neuronal nitric oxide in the inhibition of sympathetic vasoconstriction in resting and contracting skeletal muscle of healthy rats.

    PubMed

    Jendzjowsky, Nicholas G; DeLorey, Darren S

    2013-07-01

    Isoform-specific nitric oxide (NO) synthase (NOS) contributions to NO-mediated inhibition of sympathetic vasoconstriction in resting and contracting skeletal muscle are incompletely understood. The purpose of the present study was to investigate the role of neuronal NOS (nNOS) in the inhibition of sympathetic vasoconstriction in resting and contracting skeletal muscle of healthy rats. We hypothesized that acute pharmacological inhibition of nNOS would augment sympathetic vasoconstriction in resting and contracting skeletal muscle, demonstrating that nNOS is primarily responsible for NO-mediated inhibition of sympathetic vasoconstriction. Sprague-Dawley rats (n = 13) were anesthetized and instrumented with an indwelling brachial artery catheter, femoral artery flow probe, and lumbar sympathetic chain stimulating electrodes. Triceps surae muscles were stimulated to contract rhythmically at 60% of maximal contractile force. In series 1 (n = 9), the percent change in femoral vascular conductance (%FVC) in response to sympathetic stimulations delivered at 2 and 5 Hz was determined at rest and during muscle contraction before and after selective nNOS blockade with S-methyl-l-thiocitrulline (SMTC, 0.6 mg/kg iv) and subsequent nonselective NOS blockade with N(ω)-nitro-l-arginine methyl ester (l-NAME, 5 mg/kg iv). In series 2 (n = 4), l-NAME was injected first, and then SMTC was injected to determine if the effect of l-NAME on constrictor responses was influenced by selective nNOS inhibition. Sympathetic stimulation decreased FVC at rest (-25 ± 7 and -44 ± 8%FVC at 2 and 5 Hz, respectively) and during contraction (-7 ± 3 and -19 ± 5%FVC at 2 and 5 Hz, respectively). The decrease in FVC in response to sympathetic stimulation was greater in the presence of SMTC at rest (-32 ± 6 and -49 ± 8%FVC at 2 and 5 Hz, respectively) and during contraction (-21 ± 4 and -28 ± 4%FVC at 2 and 5 Hz, respectively). l-NAME further increased (P < 0.05) the sympathetic vasoconstrictor

  15. Quantifying the economic competitiveness of cellulosic biofuel pathways under uncertainty and regional sensitivity

    NASA Astrophysics Data System (ADS)

    Brown, Tristan R.

    cellulosic biofuel pathways being commercialized in eight different U.S. states under price uncertainty, utilization of pathway-specific costs of capital, and region-specific economic factors. 10-year probabilities of default in excess of 60% are calculated for all eight location scenarios considered, with default probabilities in excess of 98% calculated for seven of the eight. Negative mean 20-year NPVs are calculated for seven of the eight location scenarios.

  16. Influence of ecohydrologic feedbacks from simulated crop growth on integrated regional hydrologic simulations under climate scenarios

    NASA Astrophysics Data System (ADS)

    van Walsum, P. E. V.; Supit, I.

    2012-06-01

    Hydrologic climate change modelling is hampered by climate-dependent model parameterizations. To reduce this dependency, we extended the regional hydrologic modelling framework SIMGRO to host a two-way coupling between the soil moisture model MetaSWAP and the crop growth simulation model WOFOST, accounting for ecohydrologic feedbacks in terms of radiation fraction that reaches the soil, crop coefficient, interception fraction of rainfall, interception storage capacity, and root zone depth. Except for the last, these feedbacks are dependent on the leaf area index (LAI). The influence of regional groundwater on crop growth is included via a coupling to MODFLOW. Two versions of the MetaSWAP-WOFOST coupling were set up: one with exogenous vegetation parameters, the "static" model, and one with endogenous crop growth simulation, the "dynamic" model. Parameterization of the static and dynamic models ensured that for the current climate the simulated long-term averages of actual evapotranspiration are the same for both models. Simulations were made for two climate scenarios and two crops: grass and potato. In the dynamic model, higher temperatures in a warm year under the current climate resulted in accelerated crop development, and in the case of potato a shorter growing season, thus partly avoiding the late summer heat. The static model has a higher potential transpiration; depending on the available soil moisture, this translates to a higher actual transpiration. This difference between static and dynamic models is enlarged by climate change in combination with higher CO2 concentrations. Including the dynamic crop simulation gives for potato (and other annual arable land crops) systematically higher effects on the predicted recharge change due to climate change. Crop yields from soils with poor water retention capacities strongly depend on capillary rise if moisture supply from other sources is limited. Thus, including a crop simulation model in an integrated

  17. New mechanism under International Flood Initiative toward robustness for flood management in the Asia Pacific region

    NASA Astrophysics Data System (ADS)

    Murase, M.; Yoshitani, J.; Takeuchi, K.; Koike, T.

    2015-12-01

    Climate change is likely to result in increases in the frequency or intensity of extreme weather events. It is imperative that a good understanding is developed of how climate change affects the events that are reflected in hydrological extremes such as floods and how practitioners in water resources management deal with them. Since there is still major uncertainty as to how the impact of climate change affect actual water resources management, it is important to build robustness into management schemes and communities. Flood management under such variety of uncertainty favors the flexible and adaptive implementation both in top-down and bottom-up approaches. The former uses projections of global or spatially downscaled models to drive resource models and project resource impacts. The latter utilizes policy or planning tools to identify what changes in climate would be most threatening to their long-range operations. Especially for the bottom-up approaches, it is essential to identify the gap between what should be done and what has not been achieved for disaster risks. Indicators or index are appropriate tools to measure such gaps, but they are still in progress to cover the whole world. The International Flood Initiative (IFI), initiated in January 2005 by UNESCO and WMO in close cooperation with UNU and ISDR, IAHS and IAHR, has promoted an integrated approach to flood management to take advantage of floods and use of flood plains while reducing the social, environmental and economic risks. Its secretariat is located in ICHARM. The initiative objective is to support national platforms to practice evidence-based disaster risk reduction through mobilizing scientific and research networks at national, regional and international levels. The initiative is now preparing for a new mechanism to facilitate the integrated approach for flood management on the ground regionally in the Asia Pacific (IFI-AP) through monitoring, assessment and capacity building.

  18. Groundwater Modeling in Coastal Arid Regions Under the Influence of Marine Saltwater Intrusion

    NASA Astrophysics Data System (ADS)

    Walther, Marc; Kolditz, Olaf; Grundmann, Jens; Liedl, Rudolf

    2010-05-01

    The optimization of an aquifer's "safe yield", especially within agriculturally used regions, is one of the fundamental tasks for nowaday's groundwater management. Due to the limited water ressources in arid regions, conflict of interests arise that need to be evaluated using scenario analysis and multicriterial optimization approaches. In the context of the government-financed research project "International Water Research Alliance Saxony" (IWAS), the groundwater quality for near-coastal, agriculturally used areas is investigated under the influence of marine saltwater intrusion. Within the near-coastal areas of the study region, i.e. the Batinah plains of Northern Oman, an increasing agricultural development could be observed during the recent decades. Simultaneously, a constant lowering of the groundwater table was registered, which is primarily due to the uncontrolled and unsupervised mining of the aquifers for the local agricultural irrigation. Intensively decreased groundwater levels, however, cause an inversion of the hydraulic gradient which is naturally aligned towards the coast. This, in turn,leads to an intrusion of marine saltwater flowing inland, endangering the productivity of farms near the coast. Utilizing the modeling software package OpenGeoSys, which has been developed and constantly enhanced by the Department of Environmental Informatics at the Helmholtz Centre for Environmental Research Leipzig (UFZ; Kolditz et al., 2008), a three-dimensional, density-dependent model including groundwater flow and mass transport is currently being built up. The model, comprehending three selected coastal wadis of interest, shall be used to investigate different management scenarios. The main focus of the groundwater modelling are the optimization of well positions and pumping schemes as well as the coupling with a surface runoff model, which is also used for the determination of the groundwater recharge due to wadi runoff downstream of retention dams. Based on

  19. Long tails in regional surface temperature probability distributions with implications for extremes under global warming

    NASA Astrophysics Data System (ADS)

    Ruff, Tyler W.; Neelin, J. David

    2012-02-01

    Prior work has shown that probability distributions of column water vapor and several passive tropospheric chemical tracers exhibit longer-than-Gaussian (approximately exponential) tails. The tracer-advection prototypes explaining the formation of these long-tailed distributions motivate exploration of observed surface temperature distributions for non-Gaussian tails. Stations with long records in various climate regimes in National Climatic Data Center Global Surface Summary of Day observations are used to examine tail characteristics for daily average, maximum and minimum surface temperature probability distributions. Each is examined for departures from a Gaussian fit to the core (here approximated as the portion of the distribution exceeding 30% of the maximum). While the core conforms to Gaussian for most distributions, roughly half the cases exhibit non-Gaussian tails in both winter and summer seasons. Most of these are asymmetric, with a long, roughly exponential, tail on only one side. The shape of the tail has substantial implications for potential changes in extreme event occurrences under global warming. Here the change in the probability of exceeding a given threshold temperature is quantified in the simplest case of a shift in the present-day observed distribution. Surface temperature distributions with long tails have a much smaller change in threshold exceedances (smaller increases for high-side and smaller decreases for low-side exceedances relative to exceedances in current climate) under a given warming than do near-Gaussian distributions. This implies that models used to estimate changes in extreme event occurrences due to global warming should be verified regionally for accuracy of simulations of probability distribution tails.

  20. The production of vasoconstriction-induced residual NO modulates perfusion pressure in rat mesenteric vascular bed.

    PubMed

    Seçilmiş, M A; Özü, Ö Y; Kıroğlu, O E; Şingirik, E; Büyükafşar, K

    2014-11-01

    In the presence of nitric oxide synthase (NOS) inhibitors, the contribution of residual NO to endothelium-dependent relaxation induced by chemical agonists acetylcholine and bradykinin has been documented in resistance vessels. However, the contribution of residual NO to the vasodilatation in response to pressure and fluid shear stress is not well understood. In this study, to demonstrate the activity of residual NO, we applied a NO scavenger, hydroxocobalamin (HCX), on the phenylephrine-induced increase in perfusion pressure in the presence of NOS inhibitors, Nω-nitro-L-arginine (L-NA) or Nω-nitro-L-arginine methyl ester (L-NAME) in the rat perfused mesenteric bed. The perfusion pressure was increased by phenylephrine (1-2 µM), an α1-adrenoceptor agonist. This increase was augmented by the addition of L-NA or L-NAME. In the presence of any NOS inhibitors, the application of hydroxocobalamin (100 µM) further increased the perfusion pressure. The removal of endothelium by saponin (50 mg/L) and the use of a non-selective protein kinase inhibitor, staurosporine (5 nM), and a tyrosine kinase inhibitor, erbstatin A (30 µM), but not a calmodulin inhibitor, calmidazolium (0.5 µM), inhibited the additional pressor responses induced by L-NA or L-NAME and a combination of either of them with hydroxocobalamine. These findings show that there could be a NOS inhibitor-resistant residual NO production in response to pressure in the rat mesenteric vascular bed. This residual NO production may be associated with the activation of tyrosine kinase and protein kinases, but not calmodulin. Finally, this pressure-induced residual NO exerts a modulatory role against vasoconstriction induced by phenylephrine. PMID:24534887

  1. Leptin augments coronary vasoconstriction and smooth muscle proliferation via a Rho-kinase-dependent pathway.

    PubMed

    Noblet, Jillian N; Goodwill, Adam G; Sassoon, Daniel J; Kiel, Alexander M; Tune, Johnathan D

    2016-05-01

    Leptin has been implicated as a key upstream mediator of pathways associated with coronary vascular dysfunction and disease. The purpose of this investigation was to test the hypothesis that leptin modifies the coronary artery proteome and promotes increases in coronary smooth muscle contraction and proliferation via influences on Rho kinase signaling. Global proteomic assessment of coronary arteries from lean swine cultured with obese concentrations of leptin (30 ng/mL) for 3 days revealed significant alterations in the coronary artery proteome (68 proteins) and identified an association between leptin treatment and calcium signaling/contraction (four proteins) and cellular growth and proliferation (35 proteins). Isometric tension studies demonstrated that both acute (30 min) and chronic (3 days, serum-free media) exposure to obese concentrations of leptin potentiated depolarization-induced contraction of coronary arteries. Inhibition of Rho kinase significantly reduced leptin-mediated increases in coronary artery contractions. The effects of leptin on the functional expression of Rho kinase were time-dependent, as acute treatment increased Rho kinase activity while chronic (3 day) exposure was associated with increases in Rho kinase protein abundance. Proliferation assays following chronic leptin administration (8 day, serum-containing media) demonstrated that leptin augmented coronary vascular smooth muscle proliferation and increased Rho kinase activity. Inhibition of Rho kinase significantly reduced these effects of leptin. Taken together, these findings demonstrate that leptin promotes increases in coronary vasoconstriction and smooth muscle proliferation and indicate that these phenotypic effects are associated with alterations in the coronary artery proteome and dynamic effects on the Rho kinase pathway. PMID:26975316

  2. Optimization of isolated perfused/ventilated mouse lung to study hypoxic pulmonary vasoconstriction

    PubMed Central

    Yoo, Hae Young; Zeifman, Amy; Ko, Eun A.; Smith, Kimberly A.; Chen, Jiwang; Machado, Roberto F.; Zhao, You-Yang; Minshall, Richard D.; Yuan, Jason X.-J.

    2013-01-01

    Hypoxic pulmonary vasoconstriction (HPV) is a compensatory physiological mechanism in the lung that optimizes the matching of ventilation to perfusion and thereby maximizes gas exchange. Historically, HPV has been primarily studied in isolated perfused/ventilated lungs; however, the results of these studies have varied greatly due to different experimental conditions and species. Therefore, in the present study, we utilized the mouse isolated perfused/ventilated lung model for investigation of the role of extracellular Ca2+ and caveolin-1 and endothelial nitric oxide synthase expression on HPV. We also compared HPV using different perfusate solutions: Physiological salt solution (PSS) with albumin, Ficoll, rat blood, fetal bovine serum (FBS), or Dulbecco's Modified Eagle Medium (DMEM). After stabilization of the pulmonary arterial pressure (PAP), hypoxic (1% O2) and normoxic (21% O2) gases were applied via a ventilator in five-minute intervals to measure HPV. The addition of albumin or Ficoll with PSS did not induce persistent and strong HPV with or without a pretone agent. DMEM with the inclusion of FBS in the perfusate induced strong HPV in the first hypoxic challenge, but the HPV was neither persistent nor repetitive. PSS with rat blood only induced a small increase in HPV amplitude. Persistent and repetitive HPV occurred with PSS with 20% FBS as perfusate. HPV was significantly decreased by the removal of extracellular Ca2+ along with addition of 1 mM EGTA to chelate residual Ca2+ and voltage-dependent Ca2+ channel blocker (nifedipine 1 μM). PAP was also reactive to contractile stimulation by high K+ depolarization and U46619 (a stable analogue of thromboxane A2). In summary, optimal conditions for measuring HPV were established in the isolated perfused/ventilated mouse lung. Using this method, we further confirmed that HPV is dependent on Ca2+ influx. PMID:24015341

  3. The tripeptide ZAMI-420 inhibits thromboxane-induced gastric vasoconstriction and ischaemia.

    PubMed

    Moroni, D; Gervasi, G B; Patella, P; Visentin, L; Maselli, M A; Bergamaschi, M

    1983-01-01

    The tripeptide ZAMI-420 has been shown by Gervasi et al. (4) to be able to prevent experimentally-induced gastric damage, possibly by interfering with the synthesis and the action of thromboxane A2 (TXA2), a potent vasoconstrictor and platelet aggregator. Further studies on a canine stomach wedge preparation, supplied with a fixed flow of 10 ml/min-1 of arterial blood from the same dog have been designed to investigate this hypothesis. Bolus injection of arachidonic acid (AA) through a 30-sec incubation coil that allows the production of TXA2 resulted in a dose-related increase in resistance to flow in the stomach wedge vasculature and blanching of the gastric mucosa. This was progressively inhibited by ZAMI-420 perfused through the delay coil. Similar results were obtained with 1-benzylimidazole (BI). ZAMI-420, but not BI, produced a partial inhibition of TXA2-induced vasoconstriction when infused close to the stomach. Investigations of the antagonistic action of ZAMI-420 on the pharmacological effect of the formed TXA2 were carried out using strips of celiac and mesenteric artery from rabbits and gastric artery from dogs. Preincubation of these vascular preparations with ZAMI-420 led to progressive inhibition of the contraction induced either by the stable endoperoxide U-46619 or by CaCl2. Whittle et al. (3) reported that TXA2 may be involved in the pathogenesis of ulcerative disorders of the stomach; if so, both the inhibition of the synthesis and the antagonism of TXA2-induced effects could be of value in the prevention of experimentally-induced gastric disorders. PMID:6654624

  4. Angiotensin II type I receptor blockade attenuates reflex cutaneous vasoconstriction in aged but not young skin.

    PubMed

    Lang, James A; Kolb, Kelsey E

    2015-05-15

    Stimulation of angiotensin II type I receptors (AT1R) elicits vasoconstriction (VC) that may be occurring through the activation of a pathogenic vascular pathway such as Rho kinase (ROCK). We hypothesize that reflex cutaneous VC to whole body cooling (mean skin temperature = 30.5°C) in older humans relies in part on AT1R activation, which may explain greater ROCK activity attendant with aging. Two microdialysis (MD) fibers were placed in the forearm skin of 10 young (Y; 24 ± 1 yr) and 10 older (O; 70 ± 2 yr) individuals for infusion of 1) lactated Ringer's solution (switched to fasudil, a ROCK antagonist, after cooling); and 2) AT1R blockade with losartan. Laser Doppler flux (LDF) was measured over each MD site and cutaneous vascular conductance (CVC) was calculated (CVC = LDF/mean arterial pressure) and expressed as percent change from baseline (%ΔCVCBASELINE). In older individuals the VC response to whole body cooling was blunted (Y = -34 ± 2, O = -17 ± 3%ΔCVC) and was further attenuated at the losartan site (Y = -34 ± 3, O = -9 ± 3%ΔCVC; P < 0.05). The VC response to an exogenous 10-μM dose of angiotensin II (Y = -27 ± 3, O = -42 ± 5%ΔCVC) was completely blocked in sites pretreated with losartan or with fasudil. These data suggest that AT1R activation contributes to the reflex VC response in aged but not young skin. Furthermore, the angiotensin II component of the VC response appears to occur primarily through a ROCK-mediated mechanism. PMID:25770238

  5. Heme oxygenase-1 induction modulates hypoxic pulmonary vasoconstriction through upregulation of ecSOD.

    PubMed

    Ahmad, Mansoor; Zhao, Xiangmin; Kelly, Melissa R; Kandhi, Sharath; Perez, Oscar; Abraham, Nader G; Wolin, Michael S

    2009-10-01

    Endothelium-denuded bovine pulmonary arteries (BPA) contract to hypoxia through a mechanism potentially involving removing a superoxide-derived hydrogen peroxide-mediated relaxation. BPA organ cultured for 24 h with 0.1 mM cobalt chloride (CoCl(2)) to increase the expression and activity of heme oxygenase-1 (HO-1) is accompanied by a decrease in 5 microM lucigenin-detectable superoxide and an increase in horseradish peroxidase-luminol detectable peroxide levels. Force development to KCl in BPA was not affected by increases in HO-1, but the hypoxic pulmonary vasoconstriction (HPV) response was decreased. Organ culture with a HO-1 inhibitor (10 microM chromium mesoporphyrin) reversed the effects of HO-1 on HPV and peroxide. Treatment of HO-1-induced BPA with extracellular catalase resulted in reversal of the attenuation of HPV without affecting the force development to KCl. Increasing intracellular peroxide scavenging with 0.1 mM ebselen increased force development to KCl and partially reversed the decrease in HPV seen on induction of HO-1. HO-1 induction increases extracellular (ec) superoxide dismutase (SOD) expression without changing Cu,Zn-SOD and Mn-SOD levels. HO-1-induced BPA rings treated with the copper chelator 10 mM diethyldithiocarbamate to inactivate ecSOD and Cu,Zn-SOD showed increased superoxide and decreased peroxide to levels equal to non-HO-1-induced rings, whereas the addition of SOD to freshly isolated BPA rings attenuated HPV similar to HO-1 induction with CoCl(2). Therefore, HO-1 induction in BPA increases ecSOD expression associated with enhanced generation of peroxide in amounts that may not be adequately removed during hypoxia, leading to an attenuation of HPV. PMID:19666846

  6. Idiopathic Pulmonary Arterial Hypertension: An Avian Model for Plexogenic Arteriopathy and Serotonergic Vasoconstriction

    PubMed Central

    Wideman, Robert F.; Hamal, Krishna R.

    2011-01-01

    Idiopathic pulmonary arterial hypertension (IPAH) is a disease of unknown cause that is characterized by elevated pulmonary arterial pressure and pulmonary vascular resistance attributable to vasoconstriction and vascular remodeling of small pulmonary arteries. Vascular remodeling includes hypertrophy and hyperplasia of smooth muscle (medial hypertrophy) accompanied in up to 80% of the cases by the formation of occlusive plexiform lesions (plexogenic arteriopathy). Patients tend to be unresponsive to vasodilator therapy and have a poor prognosis for survival when plexogenic arteriopathy progressively obstructs their pulmonary arteries. Research is needed to understand and treat plexogenic arteriopathy, but advances have been hindered by the absence of spontaneously developing lesions in existing laboratory animal models. Young domestic fowl bred for meat production (broiler chickens, broilers) spontaneously develop IPAH accompanied by semi-occlusive endothelial proliferation that progresses into fully developed plexiform lesions. Plexiform lesions develop in both females and male broilers, and lesion incidences (lung sections with lesions/lung sections examined) averaged approximately 40% in 8 to 52 week old birds. Plexiform lesions formed distal to branch points in muscular interparabronchial pulmonary arteries, and were associated with perivascular mononuclear cell infiltrates. Serotonin (5-hydroxytryptamine, 5-HT) is a potent vasoconstrictor and mitogen known to stimulate vascular endothelial and smooth muscle cell proliferation. Serotonin has been directly linked to the pathogenesis of IPAH in humans, including IPAH linked to serotonergic anorexigens that trigger the formation of plexiform lesions indistinguishable from those observed in primary IPAH triggered by other causes. Serotonin also plays a major role in the susceptibility of broilers to IPAH. This avian model of spontaneous IPAH constitutes a new animal model for biomedical research focused on the

  7. Infrared imaging to quantify the effects of nicotine-induced vasoconstriction in humans

    NASA Astrophysics Data System (ADS)

    Brunner, Siegfried; Kargel, Christian

    2009-05-01

    Smoking is the most significant source of preventable morbidity and premature mortality worldwide (WHO-2008). One of the many effects of nicotine is vasoconstriction which is triggered by the autonomic nervous system. The constriction of blood vessels e.g. of the skin's vascular bed is responsible for a decrease of the supply with oxygen and nutrients and a lowering of the skin temperature. We used infrared imaging to quantify temperature decreases caused by cigarette smoking in the extremities of smokers and also monitored heart rate as well as blood pressure. The results - including thermograms showing "temporary amputations" of the fingertips due to a significant temperature drop - can help increase the awareness of the dangers of smoking and the success of withdrawal programs. Surprisingly, in our control persons (3 brave non-smoking volunteers who smoked a cigarette) we also found temperature increases suggesting that vasodilation (widening of blood vessels) was provoked by cigarettes. To verify this unexpected finding and eliminate effects from the 4000 chemical compounds in the smoke, we repeated the experiment following a stringent protocol ruling out physiological and psychological influences with 9 habitual smokers and 17 nonsmokers who all chew gums with 2 mg of nicotine. Task-optimized digital image processing techniques (target detection, image-registration and -segmentation) were applied to the acquired infrared image sequences to automatically yield temperature plots of the fingers and palm. In this paper we present the results of our study in detail and show that smokers and non-smokers respond differently to the administration of nicotine.

  8. Notch Activation of Ca(2+) Signaling in the Development of Hypoxic Pulmonary Vasoconstriction and Pulmonary Hypertension.

    PubMed

    Smith, Kimberly A; Voiriot, Guillaume; Tang, Haiyang; Fraidenburg, Dustin R; Song, Shanshan; Yamamura, Hisao; Yamamura, Aya; Guo, Qiang; Wan, Jun; Pohl, Nicole M; Tauseef, Mohammad; Bodmer, Rolf; Ocorr, Karen; Thistlethwaite, Patricia A; Haddad, Gabriel G; Powell, Frank L; Makino, Ayako; Mehta, Dolly; Yuan, Jason X-J

    2015-09-01

    Hypoxic pulmonary vasoconstriction (HPV) is an important physiological response that optimizes the ventilation/perfusion ratio. Chronic hypoxia causes vascular remodeling, which is central to the pathogenesis of hypoxia-induced pulmonary hypertension (HPH). We have previously shown that Notch3 is up-regulated in HPH and that activation of Notch signaling enhances store-operated Ca(2+) entry (SOCE), an important mechanism that contributes to pulmonary arterial smooth muscle cell (PASMC) proliferation and contraction. Here, we investigate the role of Notch signaling in HPV and hypoxia-induced enhancement of SOCE. We examined SOCE in human PASMCs exposed to hypoxia and pulmonary arterial pressure in mice using the isolated perfused/ventilated lung method. Wild-type and canonical transient receptor potential (TRPC) 6(-/-) mice were exposed to chronic hypoxia to induce HPH. Inhibition of Notch signaling with a γ-secretase inhibitor attenuates hypoxia-enhanced SOCE in PASMCs and hypoxia-induced increase in pulmonary arterial pressure. Our results demonstrate that hypoxia activates Notch signaling and up-regulates TRPC6 channels. Additionally, treatment with a Notch ligand can mimic hypoxic responses. Finally, inhibition of TRPC6, either pharmacologically or genetically, attenuates HPV, hypoxia-enhanced SOCE, and the development of HPH. These results demonstrate that hypoxia-induced activation of Notch signaling mediates HPV and the development of HPH via functional activation and up-regulation of TRPC6 channels. Understanding the molecular mechanisms that regulate cytosolic free Ca(2+) concentration and PASMC proliferation is critical to elucidation of the pathogenesis of HPH. Targeting Notch regulation of TRPC6 will be beneficial in the development of novel therapies for pulmonary hypertension associated with hypoxia. PMID:25569851

  9. Macro-to-micro cortical vascular imaging underlies regional differences in ischemic brain.

    PubMed

    Dziennis, Suzan; Qin, Jia; Shi, Lei; Wang, Ruikang K

    2015-01-01

    The ability to non-invasively monitor and quantify hemodynamic responses down to the capillary level is important for improved diagnosis, treatment and management of neurovascular disorders, including stroke. We developed an integrated multi-functional imaging system, in which synchronized dual wavelength laser speckle contrast imaging (DWLS) was used as a guiding tool for optical microangiography (OMAG) to test whether detailed vascular responses to experimental stroke in male mice can be evaluated with wide range sensitivity from arteries and veins down to the capillary level. DWLS enabled rapid identification of cerebral blood flow (CBF), prediction of infarct area and hemoglobin oxygenation over the whole mouse brain and was used to guide the OMAG system to hone in on depth information regarding blood volume, blood flow velocity and direction, vascular architecture, vessel diameter and capillary density pertaining to defined regions of CBF in response to ischemia. OMAG-DWLS is a novel imaging platform technology to simultaneously evaluate multiple vascular responses to ischemic injury, which can be useful in improving our understanding of vascular responses under pathologic and physiological conditions, and ultimately facilitating clinical diagnosis, monitoring and therapeutic interventions of neurovascular diseases. PMID:25941797

  10. Horse impoundments under Control of Horses legislation in the Munster region of Ireland: factors affecting euthanasia.

    PubMed

    Cullinane, M; O'Sullivan, E; Collins, D M; Byrne, A W; More, S J

    2015-01-24

    Recently, considerable international attention has been paid to the problem of unwanted horses. In Ireland, stray horses, particularly in urban areas, are a further problem. The Control of Horses Act 1996 was enacted in response to an ongoing problem of uncontrolled horses in public places. As yet, no research work has been conducted focusing on stray horses in Ireland. This paper describes horses impounded under the Act in the Munster region of Ireland during 2005-2012 and the factors influencing decisions regarding their disposal. A logistic regression model was developed to investigate factors influencing the probability that a horse was euthanised during impoundment. In total, 3625 seizure events were recorded, most towards the end of the study period. Predictors for euthanasia during 2010-2012 included seizure location, sex, age, colour, body condition score and year. This study highlights the problem of stray horses in Ireland, particularly in urban areas. There is a need for rigorous enforcement of newly enacted horse identification legislation, allowing a fully integrated traceability system. More is required to manage the long-established societal problems of stray horses in urban settings, with a uniform approach by all Local Authorities being long overdue. PMID:25376504

  11. Macro-to-micro cortical vascular imaging underlies regional differences in ischemic brain

    NASA Astrophysics Data System (ADS)

    Dziennis, Suzan; Qin, Jia; Shi, Lei; Wang, Ruikang K.

    2015-05-01

    The ability to non-invasively monitor and quantify hemodynamic responses down to the capillary level is important for improved diagnosis, treatment and management of neurovascular disorders, including stroke. We developed an integrated multi-functional imaging system, in which synchronized dual wavelength laser speckle contrast imaging (DWLS) was used as a guiding tool for optical microangiography (OMAG) to test whether detailed vascular responses to experimental stroke in male mice can be evaluated with wide range sensitivity from arteries and veins down to the capillary level. DWLS enabled rapid identification of cerebral blood flow (CBF), prediction of infarct area and hemoglobin oxygenation over the whole mouse brain and was used to guide the OMAG system to hone in on depth information regarding blood volume, blood flow velocity and direction, vascular architecture, vessel diameter and capillary density pertaining to defined regions of CBF in response to ischemia. OMAG-DWLS is a novel imaging platform technology to simultaneously evaluate multiple vascular responses to ischemic injury, which can be useful in improving our understanding of vascular responses under pathologic and physiological conditions, and ultimately facilitating clinical diagnosis, monitoring and therapeutic interventions of neurovascular diseases.

  12. Large-scale climate patterns and precipitation in an arid endorheic region: linkage and underlying mechanism

    NASA Astrophysics Data System (ADS)

    Shi, Pengfei; Yang, Tao; Zhang, Ke; Tang, Qiuhong; Yu, Zhongbo; Zhou, Xudong

    2016-04-01

    The interactions between a range of large-scale climate oscillations and their quantitative links with precipitation are basic prerequisites to understand the hydrologic cycle. Restricted by the current limited knowledge on underlying mechanisms, statistical methods (e.g. correlation methods) are often used rather than a physical-based model. However, available correlation methods generally fail to explain the interactions among a wide range of climate oscillations and associated effects on the water cycle. This study presents a new probabilistic analysis approach by means of a state-of-the-art Copula-based joint probability distribution to characterize the aggregated behaviors for large-scale climate patterns and their connections to precipitation. We applied this method to identify the complex connections between climate patterns (westerly circulation (WEC), El Niño-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO)) and seasonal precipitation over a typical endorheic region, the Tarim River Basin in central Asia. Results show that the interactions among multiple climate oscillations are non-uniform in most seasons and phases. Certain joint extreme phases can significantly trigger extremes (flood and drought) owing to the amplification effect among climate oscillations. We further find that the connection is mainly due to the complex effects of climatic and topographical factors.

  13. [Decomposition of herbaceous species in reservoir riparian region of Three Gorges Reservoir under flooding condition].

    PubMed

    Yuan, Qing-Ye; Xie, Zong-Qiang; Yang, Lin-Sen; Xiong, Gao-Ming; Li, Zhao-Jia; Fan, Da-Yong

    2014-08-01

    A total of 10 annuals and perennials of herbaceous species were investigated in reservoir riparian region of Three Gorges Reservoir. The correlations between the plants' nutrient release rate and the substrate composition and structural matter were studied under flooding condition. The decomposition rates of different species differed substantially, with the maximum of Alternanthera philoxeroides (decomposition rate constant k = 0.0228 d(-1)) and the minimum of Microstegium vimineum (k = 0.0029 d(-1)). There was no significant difference in k between annuals and perennials. There was no significant difference in nitrogen and phosphorus contents between annuals and perennials. Paspalum paspaloides and Bidens pilosa released more nutrients into the water than the other species. A. philoxeroides had a higher potential to release nitrogen while it had little effect on water phosphorus compared with the other species. Total N, P contents in the water were negatively correlated with the plants' decomposition rate, initial C content, C:N ratio, lignin:N ratio, and positively correlated with initial contents of K, Ca and N in plants. PMID:25509072

  14. Macro-to-micro cortical vascular imaging underlies regional differences in ischemic brain

    PubMed Central

    Dziennis, Suzan; Qin, Jia; Shi, Lei; Wang, Ruikang K.

    2015-01-01

    The ability to non-invasively monitor and quantify hemodynamic responses down to the capillary level is important for improved diagnosis, treatment and management of neurovascular disorders, including stroke. We developed an integrated multi-functional imaging system, in which synchronized dual wavelength laser speckle contrast imaging (DWLS) was used as a guiding tool for optical microangiography (OMAG) to test whether detailed vascular responses to experimental stroke in male mice can be evaluated with wide range sensitivity from arteries and veins down to the capillary level. DWLS enabled rapid identification of cerebral blood flow (CBF), prediction of infarct area and hemoglobin oxygenation over the whole mouse brain and was used to guide the OMAG system to hone in on depth information regarding blood volume, blood flow velocity and direction, vascular architecture, vessel diameter and capillary density pertaining to defined regions of CBF in response to ischemia. OMAG-DWLS is a novel imaging platform technology to simultaneously evaluate multiple vascular responses to ischemic injury, which can be useful in improving our understanding of vascular responses under pathologic and physiological conditions, and ultimately facilitating clinical diagnosis, monitoring and therapeutic interventions of neurovascular diseases. PMID:25941797

  15. 7 CFR 1486.103 - Are regional projects possible under the program?

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... consideration provided such projects target qualifying emerging markets in the specified region. CCC may consider activities which target qualified emerging markets in a specific region, but are conducted in a non-emerging market because of its importance as a central location and ease of access to that region....

  16. [Concentration distribution of metal elements in atmospheric aerosol under different weather conditions in Qingdao Coastal Region].

    PubMed

    Chen, Xiao-Jing; Qi, Jian-Hua; Liu, Ning; Zhang, Xiang-Yu; Shen, Heng-Qing; Liu, Ming-Xu

    2014-10-01

    To know the influence of different weather conditions on the concentration of metal elements in aerosols in the coastal region, total suspended particles (TSP) samples were collected from April to May 2012, and August 2012 to March 2013 in the Qingdao coastal region, and common trace metals were analyzed by using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). The results showed that Al, Ca, Fe, Na, K and Mg were the dominant metal elements in TSP, and the sum of the six elements accounted for 94.2% of the sum of all metals. TSP and metal elements had significant monthly variations, Fe, Al, K, Ca, Mg, Zn, Ba, Mn, Ti, Sr and Li had the highest concentration in November and January, while Be, Sc, Co, Ni and Cr showed the highest value in January. Na had the highest concentration in August, November and February, and the lowest in December. Pb had the highest concentration in January and February, and the lowest in August and December. Enrichment factors indicated that Be, Co, Al, Ca, Fe, K, Mg, Mn, Sr and Ti were mainly affected by natural sources; Li, Cr, Ni, Zn, Ba and Na were affected by natural sources and part of anthropogenic sources; Pb was mainly from anthropogenic sources. Different weather conditions had great impact on TSP and metal elements concentrations, all the measured metals had the highest concentrations in smog except Ti. Compared with the sunny day, the concentration of atmospheric particulate Ti decreased, while the other elements increased by 1 to 4 times in smog. Li, Be, Cr, Ni, Al, Fe, Mg and Mn had little variation in concentration in foggy day, and the concentration of Pb and Na increased considerably. The concentration of Co, Ca and Ti reduced obviously in fog. Except for Cr, Co and Ti, the other elements increased by 1 to 3 times in haze. Most of the elements had the minimal enrichment factors in sunny day, while the other had the maximal enrichment factor in

  17. A Fast Radiative Transfer Parameterization Under Cloudy Condition in Solar Spectral Region

    NASA Astrophysics Data System (ADS)

    Yang, Q.; Liu, X.; Yang, P.; Wang, C.

    2014-12-01

    The Climate Absolute Radiance and Refractivity Observatory (CLARREO) system, which is proposed and developed by NASA, will directly measure the Earth's thermal infrared spectrum (IR), the spectrum of solar radiation reflected by the Earth and its atmosphere (RS), and radio occultation (RO). IR, RS, and RO measurements provide information on the most critical but least understood climate forcings, responses, and feedbacks associated with the vertical distribution of atmospheric temperature and water vapor, broadband reflected and emitted radiative fluxes, cloud properties, surface albedo, and surface skin temperature. To perform Observing System Simulation Experiments (OSSE) for long term climate observations, accurate and fast radiative transfer models are needed. The principal component-based radiative transfer model (PCRTM) is one of the efforts devoted to the development of fast radiative transfer models for simulating radiances and reflecatance observed by various hyperspectral instruments. Retrieval algorithm based on PCRTM forward model has been developed for AIRS, NAST, IASI, and CrIS. It is very fast and very accurate relative to the training radiative transfer model. In this work, we are extending PCRTM to UV-VIS-near IR spectral region. To implement faster cloudy radiative transfer calculations, we carefully investigated the radiative transfer process under cloud condition. The cloud bidirectional reflectance was parameterized based on off-line 36-stream multiple scattering calculations while few other lookup tables were generated to describe the effective transmittance and reflectance of the cloud-clear-sky coupling system in solar spectral region. The bidirectional reflectance or the irradiance measured by satellite may be calculated using a simple fast radiative transfer model providing the type of cloud (ice or water), optical depth of the cloud, optical depth of both atmospheric trace gases above and below clouds, particle size of the cloud, as well

  18. Assimilation of hyperspectral infrared sounder radiances under cloudy skies in a regional NWP model

    NASA Astrophysics Data System (ADS)

    Wang, Pei

    Satellite measurements are an important source of global observations in support of numerical weather prediction (NWP). The assimilation of satellite radiances under clear skies has greatly improved NWP forecast scores. Since most of the data assimilation models are used for the clear radiances assimilation, an important step for satellite radiances assimilation is the clear location detection. Good clear detection could effectively remove the cloud contamination and keep the clear observations for assimilation. In this dissertation, a new detection method uses collocated high spatial resolution imager data onboard the same platform as the satellite sounders to help IR sounders subpixel cloud detection, such as the Atmospheric Infrared Sounder (AIRS) and Moderate Resolution Imaging Spectroradiometer (MODIS), the Crosstrack Infrared Sounder (CrIS) and Visible Infrared Imaging Radiometer Suite (VIIRS). The MODIS cloud mask provides a level of confidence for the observed skies to help AIRS Field-of-View (FOVs) cloud detection. By reducing the cloud contamination, a cold bias in the temperature field and a wet bias in the moisture field are corrected for the atmospheric analysis fields. These less cloud affected analysis fields further improve hurricane track and intensity forecast. The availability of satellite observations that can be assimilated in the model is limited if only the clear radiances are assimilation. An effective way to use the thermodynamic information under partially cloudy regions is to assimilate the "cloud-cleared" radiances (CCRs); CCRs are also called clear equivalent radiances. Because the CCRs are the equivalent clear radiances from the partially cloudy FOVs, they can be directly assimilated into the current data assimilation models without modifications. The AIRS CCRs are assimilated and compared with the AIRS using stand-alone cloud detection and collocated cloud detection. The assimilation of AIRS cloud-cleared radiances directly affects

  19. Seismic images under the Beijing region inferred from P and PmP data

    NASA Astrophysics Data System (ADS)

    Lei, Jianshe; Xie, Furen; Lan, Congxin; Xing, Chengqi; Ma, Shizhen

    2008-07-01

    In this study a new tomographic method is applied to over 1500 high-quality PmP (Moho reflected wave) travel-time data as well as over 38,500 high-quality first P-wave arrivals to determine a detailed 3D crustal velocity structure under Beijing and adjacent areas. Results of detailed resolution analyses show that the PmP data can significantly improve the resolution of the model in the middle and lower crust. After the PmP data are included in the tomographic inversion, our new model not only displays the tectonic feature appeared in the previous studies, but also reveals some new features. The Zhangjiakou-Bohai Sea fault zone (Zhang-Bo zone) is imaged as prominent and continuous low-velocity (low-V) anomalies in the shallower crust, while in the middle and lower crust it shows intermittent low-V anomalies extending down to the uppermost mantle. Furthermore, the pattern of low-V anomalies is different along the Zhang-Bo zone from the southeast to the northwest, indicating that there exist large differences in the dynamic evolution of Taihangshan and Yanshan uplifts and North China depression basin. Prominent low-V anomalies are visible under the source area of the 4 July 2006 Wen-An earthquake (M 5.1), suggesting that the occurrence of the Wen-An earthquake is possibly related to the effect of the crustal fluids probably caused by the upwelling of the hot and wet asthenospheric materials due to the deep dehydration of the stagnant Pacific slab in the mantle transition zone. The fluids in the lower crust may cause the weakening of the seismogenic layer in the upper and middle crust and thus contribute to the initiation of the Wen-An earthquake. This is somewhat similar to the cause of the 1695 Sanhe-Pinggu earthquake and the 1976 Tangshan earthquake in the region, as well as the 1995 Kobe earthquake in Japan and the 2001 Bhuj earthquake in India.

  20. Evidences of Attenuation Zones Under Vesuvius Volcano By Local and Regional Seismicity

    NASA Astrophysics Data System (ADS)

    Cubellis, E.; Marturano, A.

    corresponding to the vesuvian area testifying the presence of a probable shallow large structure characterized by ductile beahaviour . The quality factor, obtained from local seismicity, and the extension of the circular attenuation zone, observed by regional earthquake, caracterise the attenu- ation source under Vesuvius volcano.

  1. Investigation of Regional Drivers for Discharge Variability in the Blue Nile Basin under Climate Change Conditions

    NASA Astrophysics Data System (ADS)

    Tecklenburg, J.; Hattermann, F. F.; Liersch, S.

    2012-04-01

    A discharge time series is the result of complex and interacting processes. Important for the runoff variability are catchment characteristics like the basin size and shape, gradient of altitude and exposition as well as micro- and macroclimatic conditions. The discharge dynamic of the Blue Nile is predominantly controlled by the monsoon variability. Due to the steep gradients in the Ethiopian highlands, the surface flow component represents the main fraction of the total discharge. The composition of discharge and the resulting time response of river runoff is further a function of subsurface retention and surface roughness. Thus, the soil surface characteristics and thereby the land use are main factors controlling formation of local water availability in the Upper Blue Nile basin. During the last 30 years the continual transformation of forest and grassland to cropland reduced the total forest area of Ethiopia to 2.5 % with respect to the total area. Regarding the discharge formation process, land cover change supports generation of surface flow because of degradation of the surface roughness with two mainly negative effects: more surface runoff and less vegetation cover leads to erosion and degradation of soils. On the other hand, the water available for plants (soil moisture) may be reduced by a decreasing infiltration rate. Both effects have consequences for agricultural production and lead to an increasing demand for irrigation. Thus, the combination of the processes may accelerate the negative environmental response which makes the system highly vulnerable and sensitive to changes in driving forces. This study aims at analyzing the correlation of possible regional drivers with the inter-seasonal and inter-annual variability of subcatchment discharge generation. The study will be carried out applying the eco-hydrological model SWIM (Soil and Water Integrated Model) driven by observed and scenario climate data. Based on satellite image information the effect

  2. Pollen flow of wheat under natural conditions in the Huanghuai River Wheat Region, China.

    PubMed

    Sun, Ai-Qing; Zhang, Chun-Qing; Wu, Cheng-Lai; Gao, Qing-Rong

    2015-01-01

    The transgenic pollen spread is the main pathway of transgenic plant gene flow. The maximum distance of pollen dispersal (horizontal), the spatial dynamics of pollen movement (vertical), and the patterns of pollen dispersal are important considerations in biosafety assessments of genetically modified crops. To evaluate wheat (Triticum aestivum) pollen dispersal, we measured the pollen suspension velocity and analyzed pollen dispersal patterns under natural conditions in the Huanghuai River wheat-growing region in 2009. The pollen suspension velocity was 0.3-0.4 m/s. The highest pollen densities were detected in the north, northwest, and south of the pollen source. Pollen was dispersed over distances greater than 245 m in the northwest and northeast directions. At the pollen source center, pollen density decreased with increasing vertical height. In the north of the pollen source, the pollen density from 65 m to 225 m showed a wave-mode decrease with increasing height. The horizontal transport of pollen over longer distances fitted polynomial equations. In the north, the pollen density was highest at 45 m from the pollen source, and decreased with increasing distance. In the northwest, the pollen density showed a double-peak trend. In the northeast, pollen density was highest from 45 m to 125 m from the source. Wind speeds greater than the pollen suspension velocity and the duration of continuous gusts were the main factors affecting pollen dispersal. This information will be useful for determining the spatial isolation distances for hybrid seed production and for the commercial production of transgenic wheat. PMID:25658025

  3. Bias correction methods for regional climate model simulations considering the distributional parametric uncertainty underlying the observations

    NASA Astrophysics Data System (ADS)

    Kim, Kue Bum; Kwon, Hyun-Han; Han, Dawei

    2015-11-01

    In this paper, we present a comparative study of bias correction methods for regional climate model simulations considering the distributional parametric uncertainty underlying the observations/models. In traditional bias correction schemes, the statistics of the simulated model outputs are adjusted to those of the observation data. However, the model output and the observation data are only one case (i.e., realization) out of many possibilities, rather than being sampled from the entire population of a certain distribution due to internal climate variability. This issue has not been considered in the bias correction schemes of the existing climate change studies. Here, three approaches are employed to explore this issue, with the intention of providing a practical tool for bias correction of daily rainfall for use in hydrologic models ((1) conventional method, (2) non-informative Bayesian method, and (3) informative Bayesian method using a Weather Generator (WG) data). The results show some plausible uncertainty ranges of precipitation after correcting for the bias of RCM precipitation. The informative Bayesian approach shows a narrower uncertainty range by approximately 25-45% than the non-informative Bayesian method after bias correction for the baseline period. This indicates that the prior distribution derived from WG may assist in reducing the uncertainty associated with parameters. The implications of our results are of great importance in hydrological impact assessments of climate change because they are related to actions for mitigation and adaptation to climate change. Since this is a proof of concept study that mainly illustrates the logic of the analysis for uncertainty-based bias correction, future research exploring the impacts of uncertainty on climate impact assessments and how to utilize uncertainty while planning mitigation and adaptation strategies is still needed.

  4. Effect of renal sympathetic nerve on adrenergically and angiotensin II-induced renal vasoconstriction in normal Wistar-Kyoto rats

    PubMed Central

    2011-01-01

    Background This study examined the effect of renal sympathetic innervation on adrenergically and angiotensin II (Ang II)-induced renal vasoconstriction in Wistar-Kyoto (WKY) rats. Methods Forty-eight WKY rats were treated with either losartan (10 mg/kg/day p.o.) or carvedilol (5 mg/kg/day p.o.) or a combination of them (10 mg/kg/day + 5 mg/kg/day p.o.) for 7 days. On day 8, the rats were anaesthetized, and renal vasoconstrictor experiments were carried out. A group of rats was subjected to acute unilateral renal denervation during the acute study. Changes in the renal vasoconstrictor responses were determined in terms of reductions in renal blood flow caused by Ang II, noradrenaline (NA), and methoxamine (ME). Results In normal animals, losartan decreased (P < 0.05) the renal vasoconstrictor response to Ang II but not to NA or ME. Carvedilol treatment, however, blunted (P < 0.05) the renal vasoconstrictor responses to Ang II and adrenergic agonists. Combination of losartan and carvedilol blunted (P < 0.05) the renal vasoconstrictor response to Ang II but augmented the responses to NA and ME (all P < 0.05). Interestingly, when denervated rats were treated with the same combination, there was a reduction (P < 0.05) in the renal vasoconstrictor responses to Ang II and adrenergic agonists. Conclusions Data suggest that the renal sympathetic nerve contributes to adrenergic agonist-mediated renal vasoconstrictions in normal rats. The data further indicate an interactive relationship between renin-angiotensin and sympathetic nervous systems in modulating adrenergically and Ang II-induced renal vasoconstriction in WKY rats. PMID:21047287

  5. NCX 4016, a nitric oxide-releasing aspirin, modulates adrenergic vasoconstriction in the perfused rat tail artery

    PubMed Central

    Rossoni, Giuseppe; Manfredi, Barbara; Soldato, Piero Del; Berti, Ferruccio

    2002-01-01

    The ability of the nitric oxide (NO)-releasing aspirin, NCX 4016, to control vasoconstrictor responses induced by electrical field stimulation (TNS) or by exogenous norepinephrine (NE) was investigated in perfused rat tail artery with intact endothelium. NCX 4016 (25, 50 and 100 μM) dose-dependently antagonized the vasoconstriction caused by TNS (from 0.5 to 64 Hz) and by NE (from 0.01 to 10 μM). The vasorelaxant activity of NCX 4016 (100 μM) in NE-precontracted arteries was concomitant with a marked increase of tissue cyclic GMP (4.9 fold, P<0.001) and was significantly antagonized by the inhibitors of soluble guanylate cyclase, methylene blue and 1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one. The effect of NCX 4016 was endothelium NO-independent since, in preparations perfused with NG-monomethyl-L-arginine (10 μM), this compound prevented the rise in basal perfusion pressure and reversed the accentuation of vasoconstrictor responses caused by NO synthase inhibition. Aspirin-moiety released by NCX 4016 inhibited the 6-keto-PGF1α formation without interfering with the vasorelaxant activity of NCX 4016, while aspirin (100 μM) was devoid of any activity against vasoconstriction induced by both TNS and NE in perfused rat tail artery. NCX 4016 moderated adrenergic vasoconstriction in perfused rat tail arteries by a direct donation of NO without involving the relaxant factors such as PGI2 and NO from endothelial cells. The results obtained with NCX 4016 in perfused rat tail artery bears some therapeutical potential in conditions associated with vascular smooth muscle hyperreactivity to adrenergic stimulation. PMID:12208780

  6. Reversible cerebral vasoconstriction syndromes and primary angiitis of the central nervous system: clinical, imaging, and angiographic comparison.

    PubMed

    Singhal, Aneesh B; Topcuoglu, Mehmet A; Fok, Joshua W; Kursun, Oguzhan; Nogueira, Raul G; Frosch, Matthew P; Caviness, Verne S

    2016-06-01

    Reversible cerebral vasoconstriction syndromes (RCVS) and primary angiitis of the central nervous system (PACNS) are invariably considered in the differential diagnosis of new cerebral arteriopathies. However, prompt and accurate diagnosis remains challenging. Here we compared the features of 159 RCVS to 47 PACNS patients and developed criteria for prompt bedside diagnosis. Recurrent thunderclap headache (TCH), and single TCH combined with either normal neuroimaging, border zone infarcts, or vasogenic edema, have 100% positive predictive value for diagnosing RCVS or RCVS-spectrum disorders. In patients without TCH and positive angiography, neuroimaging can discriminate RCVS (no lesion) from PACNS (deep/brainstem infarcts). Ann Neurol 2016;79:882-894. PMID:27043703

  7. 6-Gingerol alleviates exaggerated vasoconstriction in diabetic rat aorta through direct vasodilation and nitric oxide generation.

    PubMed

    Ghareib, Salah A; El-Bassossy, Hany M; Elberry, Ahmed A; Azhar, Ahmad; Watson, Malcolm L; Banjar, Zainy Mohammed

    2015-01-01

    The aim of the present study is to investigate the effect and potential mechanism of action of 6-gingerol on alterations of vascular reactivity in the isolated aorta from diabetic rats. Male Wistar rats were divided into two experimental groups, control and diabetics. Diabetes was induced by a single intraperitoneal injection of streptozotocin (50 mg kg(-1)), and the rats were left for 10 weeks to develop vascular complications. The effect of in vitro incubation with 6-gingerol (0.3-3 μM) on the vasoconstrictor response of the isolated diabetic aortae to phenylephrine and the vasodilator response to acetylcholine was examined. Effect of 6-gingerol was also examined on aortae incubated with methylglyoxal as an advanced glycation end product (AGE). To investigate the mechanism of action of 6-gingerol, the nitric oxide synthase inhibitor Nω-nitro-l-arginine methyl ester hydrochloride (100 μM), guanylate cyclase inhibitor methylene blue (5 μM), calcium-activated potassium channel blocker tetraethylammonium chloride (10 mM), and cyclooxygenase inhibitor indomethacin (5 μM) were added 30 minutes before assessing the direct vasorelaxant effect of 6-gingerol. Moreover, in vitro effects of 6-gingerol on NO release and the effect of 6-gingerol on AGE production were examined. Results showed that incubation of aortae with 6-gingerol (0.3-10 μM) alleviated the exaggerated vasoconstriction of diabetic aortae to phenylephrine in a concentration-dependent manner with no significant effect on the impaired relaxatory response to acetylcholine. Similar results were seen in the aortae exposed to methylglyoxal. In addition, 6-gingerol induced a direct vasodilation effect that was significantly inhibited by Nω-nitro-l-arginine methyl ester hydrochloride and methylene blue. Furthermore, 6-gingerol stimulated aortic NO generation but had no effect on AGE formation. In conclusion, 6-gingerol ameliorates enhanced vascular contraction in diabetic aortae, which may be partially

  8. Direct vasoconstriction as a possible cause for amphotericin B-induced nephrotoxicity in rats.

    PubMed Central

    Sawaya, B P; Weihprecht, H; Campbell, W R; Lorenz, J N; Webb, R C; Briggs, J P; Schnermann, J

    1991-01-01

    In anesthetized rats we tested the hypothesis that amphotericin B (AmB) reduces glomerular filtration rate (GFR) by activating the tubuloglomerular feedback (TGF) mechanism. Infusion of 1 mg/kg AmB over 50 min was followed by a reduction in kidney GFR (from 0.47 +/- 0.03 to 0.39 +/- 0.02 ml/min per 100 g body wt during the second hour after infusion; P less than 0.05) and by an increase in urine flow and urinary chloride excretion. Single-nephron GFR (SNGFR) measured in proximal (TGF interrupted) or distal tubules (TGF intact) decreased to a similar degree from 33.4 +/- 1.8 and 30.6 +/- 1.2 nl/min in the control period to 19.7 +/- 1.9 and 21.2 +/- 1.6 nl/min during the second hour after AmB infusion (P less than 0.05). Distal chloride concentrations and TGF responses to changes in loop of Henle flow rate were not significantly altered by AmB. AmB at 10(-5) M reduced the diameter of isolated perfused afferent arterioles from rabbit kidneys. In isometrically contracting rings of rabbit aorta and renal artery in vitro AmB produced endothelium-independent constriction, with half-maximal contraction (EC50) being achieved by 1.8 x 10(-6) and 2.6 x 10(-6) M in intact vessels and 1.3 x 10(-6) and 1.7 x 10(-6) M in endothelium-denuded vessels respectively. Tension development did not occur in Ca-free media or in the presence of Ca channel blockers. Pretreatment with ouabain or Bay K 8644 potentiated the effect of AmB. The vasoconstrictive effect of AmB was counteracted by aminophylline and atrial natriuretic peptide. We conclude that the AmB-induced reduction in GFR is not caused by TGF activation and that AmB has a direct vasoconstrictor effect that is probably initiated by depolarization-induced opening of Ca channels. This effect may be an important component of the nephrotoxic actions of AmB. Images PMID:1710234

  9. Under-Ice Science in the Polar Regions with Autonomous Underwater Vehicles

    NASA Astrophysics Data System (ADS)

    Kunz, C.; Murphy, C.; Singh, H.; Das, S. B.; Jackson, R. H.; Kukulya, A.; Littlefield, R.; Maksym, T. L.; Plueddemann, A. J.; Sohn, R. A.; Straneo, F.; Wilkinson, J.

    2012-12-01

    Developments in autonomous underwater vehicle (AUV) technology over the last decade have enabled scientists to study areas of the ocean at high latitude that were previously unapproachable. In particular, advances in acoustic communications, robotic autonomy and navigation, and compact sensor technology allow AUVs to work in close proximity to sea ice, glacial fronts, and the sea floor under multi-year pack ice. We describe the technology that enabled several expeditions to both polar regions that have used Seabed-class AUVs as the primary platform for making scientific measurements. We also describe current and upcoming missions using the smaller Seabed-100 and REMUS-100 AUVs for shallow-water work near glacial fronts. Several problems must be solved in order to successfully use robots under ice. Acoustic communications must be robust enough for operators on the surface to inform the AUV of changing conditions so that the vehicle can safely return to open water on the surface - during the AGAVE and IceBell expeditions, we experienced sea ice drift rates of tens of centimeters per second, and moving ice floes that constrained the availability of open water. AUV navigation must be flexible enough for the robot to switch reference frames during a mission depending on the conditions and on the scientific objective. During a single deployment during the IceBell expedition, it was typical for the robot to switch from ship-relative (using acoustic transponders), to ice-relative (using a doppler velocity log), to ice-relative (using a distinct set of acoustic transponders), and back again; an AUV may also need to navigate relative to the sea floor (as during the AGAVE expedition). Making ice-relative measurements also requires taking ice floe rotation into account, and on-board navigation relative to a rotating frame may be necessary. Finally, specialized scenarios such as when navigating near a glacial front require navigation relative to vertical, rather than horizontal

  10. Modeling for regional ecosystem sustainable development under uncertainty--A case study of Dongying, China.

    PubMed

    Zhang, K; Li, Y P; Huang, G H; You, L; Jin, S W

    2015-11-15

    In this study, a superiority-inferiority two-stage stochastic programming (STSP) method is developed for planning regional ecosystem sustainable development. STSP can tackle uncertainties expressed as fuzzy sets and probability distributions; it can be used to analyze various policy scenarios that are associated with different levels of economic penalties when the promised targets are violated. STSP is applied to a real case of planning regional ecosystem sustainable development in the City of Dongying, where ecosystem services valuation approaches are incorporated within the optimization process. Regional ecosystem can provide direct and indirect services and intangible benefits to local economy. Land trading mechanism is introduced for planning the regional ecosystem's sustainable development, where wetlands are buyers who would protect regional ecosystem components and self-organization and maintain its integrity. Results of regional ecosystem activities, land use patterns, and land trading schemes have been obtained. Results reveal that, although large-scale reclamation projects can bring benefits to the local economy development, they can also bring with negative effects to the coastal ecosystem; among all industry activities oil field is the major contributor with a large number of pollutant discharges into local ecosystem. Results also show that uncertainty has an important role in successfully launching such a land trading program and trading scheme can provide more effective manner to sustain the regional ecosystem. The findings can help decision makers to realize the sustainable development of ecological resources in the process of rapid industrialization, as well as the integration of economic and ecological benefits. PMID:26179784

  11. Constraints to Hamari sheep farming under range conditions in Darfur and Kordofan Regions of Western Sudan.

    PubMed

    Tirab, Ahmed Berima; Chimonyo, Michael

    2016-08-01

    The study was conducted to identify the major production constraints of Hamari sheep in Darfur and Kordofan Regions of Western Sudan. A structured questionnaire was administered to 128 farmers in Darfur and Kordofan. Feed shortages, prevalence of diseases and parasites, and predation were more severe in Darfur than Kordofan (P < 0.05). Thefts were ranked higher by farmers using the sedentary system compared to those using semi-nomadic system (P < 0.05). Water shortage was ranked higher by farmers with small flocks, large flocks, semi-nomadic and sedentary husbandry system in Kordofan than their counterparts in Darfur Region (P < 0.05). Farmers practising semi-nomadic husbandry system and sedentary system in Darfur region ranked diseases, parasites and predation higher than those practising semi-nomadic and sedentary system in Kordofan region (P < 0.05). Feed shortage was ranked higher as a challenge by farmers practising semi-nomadic system in Darfur Region than those practising semi-nomadic system in Kordofan Region (P < 0.05). It can be concluded that the severity of challenges facing Hamari sheep producers vary with flock size, region and production system used. PMID:27126220

  12. Regional seismic variations in the inner core under the North Pacific

    NASA Astrophysics Data System (ADS)

    Irving, J. C. E.; Deuss, A.

    2015-12-01

    An asymmetry between a nearly isotropic, faster `eastern' hemisphere and an anisotropic, slower `western' hemisphere in Earth's inner core has been revealed by previous seismic studies. However, it remains unclear if division of the inner core into just two hemispheres is too simplistic. Here, we carry out regional-scale tomography using a new body wave data set to study the hemisphere boundary region beneath the northern and central Pacific Ocean and North America. If anisotropy is not considered, then a hemispherical pattern seems to be present in the study region, though the hemisphere boundary appears to be irregular. However, once the presence of anisotropy is permitted we find that this region cannot be simply separated into an anisotropic western hemisphere and an isotropic eastern hemisphere; instead the strength of the anisotropy varies regionally. The global hemispherical pattern is not observed here, instead the strongest anisotropy is observed in the centre and south west of the study region. Some of the strongest anisotropy appears to be in the `eastern' inner core, while part of the inner core assumed to be in the western hemisphere shows weaker anisotropy. Thus, this part of the inner core displays complex variations in anisotropy which differ from a simple hemispherical division. We suggest that a long-lived global heterogeneity, such as uneven heat flow through the core-mantle boundary over a period of hundreds of millions of years, may be responsible for the observed pattern of inner core anisotropy.

  13. 40 CFR 51.916 - What are the requirements for an Ozone Transport Region under the 8-hour NAAQS?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 2 2010-07-01 2010-07-01 false What are the requirements for an Ozone... IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient Air Quality Standard § 51.916 What are the requirements for an Ozone Transport Region under the 8-hour NAAQS? (a) In...

  14. 40 CFR 51.916 - What are the requirements for an Ozone Transport Region under the 8-hour NAAQS?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient Air Quality Standard § 51.916 What are the requirements for an Ozone Transport Region under the 8-hour NAAQS? (a) In General... 40 Protection of Environment 2 2012-07-01 2012-07-01 false What are the requirements for an...

  15. 40 CFR 51.916 - What are the requirements for an Ozone Transport Region under the 8-hour NAAQS?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient Air Quality Standard § 51.916 What are the requirements for an Ozone Transport Region under the 8-hour NAAQS? (a) In General... 40 Protection of Environment 2 2013-07-01 2013-07-01 false What are the requirements for an...

  16. 40 CFR 51.916 - What are the requirements for an Ozone Transport Region under the 8-hour NAAQS?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient Air Quality Standard § 51.916 What are the requirements for an Ozone Transport Region under the 8-hour NAAQS? (a) In General... 40 Protection of Environment 2 2014-07-01 2014-07-01 false What are the requirements for an...

  17. 40 CFR 51.916 - What are the requirements for an Ozone Transport Region under the 8-hour NAAQS?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient Air Quality Standard § 51.916 What are the requirements for an Ozone Transport Region under the 8-hour NAAQS? (a) In General... 40 Protection of Environment 2 2011-07-01 2011-07-01 false What are the requirements for an...

  18. Land Claims and Native Manpower. Staffing Regional and Village Corporations under Alaska Native Claims Settlement Act of 1971.

    ERIC Educational Resources Information Center

    Kleinfeld, Judith; And Others

    An exploratory examination of the professional, technical, and clerical manpower needs of Alaskan regional and village corporations established under the Native Land Claims Settlement Act, this report recognized that critical staffing needs can only be met by carefully designed educational and training programs. The staffing demand analyses were,…

  19. Nitric oxide (NO) inhibits antigen-stimulated increases in vasoconstriction and glycogenolysis in perfused livers derived from sensitized rats

    SciTech Connect

    Hines, K.L.; Bates, J.N.; Fisher, R.A. )

    1991-03-11

    Recent studies in the authors laboratory demonstrated that infusion of antigen into perfused livers from sensitized rats produces increases in hepatic portal pressure, increases in hepatic glucose output and decreases in hepatic oxygen consumption. In the present study, effects of NO on these hepatic responses to antigen challenge were investigated. Infusion of NO into perfused livers from sensitized rats attenuated ovalbumin induced increases in hepatic portal pressure and glucose output approximately 85% and 90%, respectively, and abolished ovalbumin-induced decreases in hepatic oxygen consumption. The duration of ovalbumin-stimulated increases in hepatic portal pressure was reduced nearly 90% by NO. Similarly, infusion of NO into perfused livers from sensitized rats inhibited increases in hepatic portal pressure and glucose output in response to platelet-activating factor (PAF) nearly 80 and 90%, respectively. In contrast, NO inhibited completely hepatic vasoconstriction in response to phenylephrine without altering glycogenolytic responses to this {alpha}-adrenergic agonist. These results provide evidence for regulatory effects of NO on hemodynamic and glycogenolytic responses to antigen in perfused livers from sensitized rats. These observations support previous findings which suggest that hepatic responses to sensitizing antigen may be mediated by PAF or other autacoid mediators which stimulate glycogenolysis in liver by indirect mechanisms involving hepatic vasoconstriction.

  20. Modulation of pain in pediatric sickle cell disease: understanding the balance between endothelin mediated vasoconstriction and apelin mediated vasodilation

    PubMed Central

    Smith, Terika P.; Schlenz, Alyssa M.; Schatz, Jeffrey C.; Maitra, Rangan; Sweitzer, Sarah M.

    2014-01-01

    Children with sickle cell disease (SCD) have painful vaso-occlusive episodes (VOE), which often reoccur across the individual's lifespan. Vaso-constrictive and vaso-dilatory molecules have been hypothesized to play a role in VOEs. Endothelin-1 (ET-1) is a potent vasoconstrictor that is released during VOEs and is correlated with pain history. Apelin is a vaso-dilatory peptide that also has a modulatory role in pain processing. We hypothesize that the ratio between vaso-dilatory and vaso-constrictive tone in children with SCD may be a marker of pain sensitization and vaso-occlusion. Plasma endothelin and apelin levels were measured in 47 children with SCD. Procedural and baseline pain were assessed via child- and caregiver-reports and observational distress. Pain history was assessed using retrospective chart review. Plasma apelin was related to age, with decreased levels in older children. The ratio between apelin and ET-1 was negatively correlated to observational baseline pain. The ratio between apelin and Big ET was negatively correlated to caregiver ratings of baseline pain and positively correlated to history of VOEs, which is possibly due to hydroxyurea treatment. These results suggest that an imbalance in the apelin and endothelin systems may contribute to an increasing number of VOEs and baseline pain in children with SCD. PMID:25486928

  1. Enhanced Endothelin-1 Mediated Vasoconstriction of the Ophthalmic Artery May Exacerbate Retinal Damage after Transient Global Cerebral Ischemia in Rat

    PubMed Central

    Blixt, Frank W.; Johansson, Sara Ellinor; Johnson, Leif; Haanes, Kristian Agmund; Warfvinge, Karin; Edvinsson, Lars

    2016-01-01

    Cerebral vasculature is often the target of stroke studies. However, the vasculature supplying the eye might also be affected by ischemia. The aim of the present study was to investigate if the transient global cerebral ischemia (GCI) enhances vascular effect of endothelin-1 (ET-1) and 5-hydroxytryptamine/serotonin (5-HT) on the ophthalmic artery in rats, leading to delayed retinal damage. This was preformed using myography on the ophthalmic artery, coupled with immunohistochemistry and electroretinogram (ERG) to assess the ischemic consequences on the retina. Results showed a significant increase of ET-1 mediated vasoconstriction at 48 hours post ischemia. The retina did not exhibit any morphological changes throughout the study. However, we found an increase of GFAP and vimentin expression at 72 hours and 7 days after ischemia, indicating Müller cell mediated gliosis. ERG revealed significantly decreased function at 72 hours, but recovered almost completely after 7 days. In conclusion, we propose that the increased contractile response via ET-1 receptors in the ophthalmic artery after 48 hours may elicit negative retinal consequences due to a second ischemic period. This may exacerbate retinal damage after ischemia as illustrated by the decreased retinal function and Müller cell activation. The ophthalmic artery and ET-1 mediated vasoconstriction may be a valid and novel therapeutic target after longer periods of ischemic insults. PMID:27322388

  2. Regional and cardiac haemodynamic effects of NG-nitro-L-arginine methyl ester in conscious, Long Evans rats.

    PubMed Central

    Gardiner, S. M.; Compton, A. M.; Kemp, P. A.; Bennett, T.

    1990-01-01

    1. Regional haemodynamic responses to i.v. bolus doses (0.1-10.0 mg kg-1) of NG-nitro-L-arginine methyl ester (L-NAME) were measured in conscious, Long Evans rats (n = 8) chronically instrumented with renal, mesenteric and hindquarters pulsed Doppler flow probes and intravascular catheters. 2. L-NAME caused dose-dependent pressor effects associated with renal, mesenteric and hindquarters vasoconstrictions. The mesenteric vascular bed showed earlier onset with more rapid, and greater, maximum vasoconstrictions than the renal or hindquarters vascular beds; however, the hindquarters vasoconstriction was more persistent. D-NAME was without significant effects (n = 2). 3. Primed infusion of L-arginine (100 mg kg-1 bolus followed by 100 mg kg-1 h-1 infusion), starting 10 min after an i.v. bolus injection of L-NAME (10 mg kg-1), caused significant reversal of the pressor responses, and renal and mesenteric vasoconstrictions, but not of the hindquarters vasoconstriction. Primed infusions of L-arginine (100 mg kg-1, 100 mg kg-1 h-1) starting 5 min after L-NAME (1 mg kg-1) additionally caused some reversal of the hindquarters vasoconstriction, but this effect was transient. 4. Primed infusion of L-arginine (100 mg kg-1, 100 mg kg-1 h-1) starting 30 min before i.v. bolus injection of L-NAME (10 mg kg-1) caused significant attenuation of the pressor effects and the renal and mesenteric vasoconstrictions but not of the hindquarters vasoconstriction.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2076481

  3. Region-confined restoration method for motion-blurred star image of the star sensor under dynamic conditions.

    PubMed

    Ma, Liheng; Bernelli-Zazzera, Franco; Jiang, Guangwen; Wang, Xingshu; Huang, Zongsheng; Qin, Shiqiao

    2016-06-10

    Under dynamic conditions, the centroiding accuracy of the motion-blurred star image decreases and the number of identified stars reduces, which leads to the degradation of the attitude accuracy of the star sensor. To improve the attitude accuracy, a region-confined restoration method, which concentrates on the noise removal and signal to noise ratio (SNR) improvement of the motion-blurred star images, is proposed for the star sensor under dynamic conditions. A multi-seed-region growing technique with the kinematic recursive model for star image motion is given to find the star image regions and to remove the noise. Subsequently, a restoration strategy is employed in the extracted regions, taking the time consumption and SNR improvement into consideration simultaneously. Simulation results indicate that the region-confined restoration method is effective in removing noise and improving the centroiding accuracy. The identification rate and the average number of identified stars in the experiments verify the advantages of the region-confined restoration method. PMID:27409019

  4. Sensitivity of soil moisture initialization for decadal predictions under different regional climatic conditions in Europe

    NASA Astrophysics Data System (ADS)

    Khodayar, S.; Sehlinger, A.; Feldmann, H.; Kottmeier, C.

    2015-12-01

    The impact of soil initialization is investigated through perturbation simulations with the regional climate model COSMO-CLM. The focus of the investigation is to assess the sensitivity of simulated extreme periods, dry and wet, to soil moisture initialization in different climatic regions over Europe and to establish the necessary spin up time within the framework of decadal predictions for these regions. Sensitivity experiments consisted of a reference simulation from 1968 to 1999 and 5 simulations from 1972 to 1983. The Effective Drought Index (EDI) is used to select and quantify drought status in the reference run to establish the simulation time period for the sensitivity experiments. Different soil initialization procedures are investigated. The sensitivity of the decadal predictions to soil moisture initial conditions is investigated through the analysis of water cycle components' (WCC) variability. In an episodic time scale the local effects of soil moisture on the boundary-layer and the propagated effects on the large-scale dynamics are analysed. The results show: (a) COSMO-CLM reproduces the observed features of the drought index. (b) Soil moisture initialization exerts a relevant impact on WCC, e.g., precipitation distribution and intensity. (c) Regional characteristics strongly impact the response of the WCC. Precipitation and evapotranspiration deviations are larger for humid regions. (d) The initial soil conditions (wet/dry), the regional characteristics (humid/dry) and the annual period (wet/dry) play a key role in the time that soil needs to restore quasi-equilibrium and the impact on the atmospheric conditions. Humid areas, and for all regions, a humid initialization, exhibit shorter spin up times, also soil reacts more sensitive when initialised during dry periods. (e) The initial soil perturbation may markedly modify atmospheric pressure field, wind circulation systems and atmospheric water vapour distribution affecting atmospheric stability

  5. Regional dynamics of forest canopy change and underlying causal processes in the contiguous U.S.

    NASA Astrophysics Data System (ADS)

    Schleeweis, Karen; Goward, Samuel N.; Huang, Chengquan; Masek, Jeffrey G.; Moisen, Gretchen; Kennedy, Robert E.; Thomas, Nancy E.

    2013-07-01

    history of forest change processes is written into forest age and distribution and affects earth systems at many scales. No one data set has been able to capture the full forest disturbance and land use record through time, so in this study, we combined multiple lines of evidence to examine trends, for six US regions, in forest area affected by harvest, fire, wind, insects, and forest conversion to urban/surburban use. We built an integrated geodatabase for the contiguous U.S. (CONUS) with data spanning the nation and decades, from remote sensing observations of forest canopy dynamics, geospatial data sets on disturbance and conversion, and statistical inventories, to evaluate relationships between canopy change observations and casual processes at multiple scales. Results show the variability of major change processes through regions across decades. Harvest affected more forest area than any other major change processes in the North East, North Central, Southeast, and South central regions. In the Pacific Coast and Intermountain West, more forest area was affected by harvest than forest fires. Canopy change rates at regional scales confounded the trends of individual forest change processes, showing the importance of landscape scale data. Local spikes in observed canopy change rates were attributed to wind and fire events, as well as volatile harvest regimes. This study improves the geographic model of forest change processes by updating regional trends for major disturbance and conversion processes and combining data on the dynamics of fire, wind, insects, harvest, and conversion into one integrated geodatabase for the CONUS.

  6. Enhanced soil moisture drying in transitional regions under a warming climate

    NASA Astrophysics Data System (ADS)

    Cheng, Shanjun; Huang, Jianping

    2016-03-01

    We analyzed global trends of soil moisture for the period 1948-2010 using the Global Land Data Assimilation System data set. Soil moisture was dominated by negative trends, with pronounced drying over East Asia and the Sahel. Spatial analysis according to climatic region revealed that the most obvious drying occurred over transitional regions between dry and wet climates. The noticeable drying first took place in the humid transitional regions and extended to the dry transitional regions, beginning in the 1980s. The variability of soil moisture was notably related to the changes in precipitation and temperature, but with different roles. For the global average, precipitation had a dominant effect on the variability of soil moisture at interannual to decadal time scales, but temperature was the main cause of the long-term trend of soil moisture on the whole. The enhanced soil drying in the transitional regions was primarily caused by global warming, which is illustrated by regression analysis and the land surface model.

  7. Kinematic mapping reveals different spatial distributions of center of pressure high-speed regions under somatosensory loss.

    PubMed

    Portela, Fellipe M; Ferreira, Arthur S

    2014-01-01

    The spatial distribution of center-of-pressure speed during postural tasks and its changes due to somatosensory constraint (temporary ischemic hypoxia on ankle/feet) were investigated in young, healthy subjects (n = 13). A single high-speed region in the central region of the statokinesigram was observed during postural tasks with full sensory information. A significant increase in the quantity of high-speed regions was observed during ischemia and somatosensory constraint, whereas a significant increase in the quantity of high-speed regions localized more distant to the center of center-of-pressure area occurred under somatosensory constraints, suggesting a redirection of center-of-pressure trajectory to adjust the position of the center of mass with respect to the egocentric reference of balance. PMID:24945569

  8. Hi-C Observations of an Active Region Corona, and Investigation of the Underlying Magnetic Structure

    NASA Technical Reports Server (NTRS)

    Tiwari, Sanjiv K.; Alexander, Caroline E.; Winebarger, Amy R.; Moore, Ronald L.

    2014-01-01

    Hi-C: first observational evidence of field line braiding in the AR corona; NLFFF extrapolations support. Flux emergence and/or cancellation in the coronal braided region generate large stresses and tension in the coronal field loops which is released as heat in the corona. The field in these sub-regions are highly sheared and have apparent high speed plasma flows, therefore, the contribution from shearing flows to power the coronal and transition region heating can not be ruled out! The spatial resolution of Hi-­C is five times better than AIA. The cadence of Hi-C is 2.5 - 6 times better than AIA. The 193 Å was selected because of the strong emission line of Fe XII (peak formation temperature of 1.5 MK). Hi-­C collected data for 345 s @ 5.4 s cadence. The Hi-C target region was NOAA AR 11520; 11 July 2012, 18:51-18:57 UT. NLFFF extrapolation confirms the braided structure, and free magnetic energy estimates in the given volume.

  9. New England Colleges under Stress: Presidential Voices from the Region's Smaller Colleges

    ERIC Educational Resources Information Center

    Halfond, Jay A.; Stokes, Peter

    2013-01-01

    Shifting demography, rising operating expenses, plummeting state and federal support, intensified competition, broken financial models… these are just a few of the complex challenges facing New England higher education institutions. Given these tensions, who would be surprised if college presidents in the region weren't occasionally plagued by…

  10. 40 CFR Appendix Y to Part 51 - Guidelines for BART Determinations Under the Regional Haze Rule

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... regional haze rule is found in this part at 40 CFR 51.300 through 51.309. These regulations require, in 40 CFR 51.308(e), that certain types of existing stationary sources of air pollutants install best... CFR 81.401 through 81.437, and you can find a map of the Class I areas at the following Internet...

  11. 40 CFR Appendix Y to Part 51 - Guidelines for BART Determinations Under the Regional Haze Rule

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... regional haze rule is found in this part at 40 CFR 51.300 through 51.309. These regulations require, in 40 CFR 51.308(e), that certain types of existing stationary sources of air pollutants install best... CFR 81.401 through 81.437, and you can find a map of the Class I areas at the following Internet...

  12. 40 CFR Appendix Y to Part 51 - Guidelines for BART Determinations Under the Regional Haze Rule

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... regional haze rule is found in this part at 40 CFR 51.300 through 51.309. These regulations require, in 40 CFR 51.308(e), that certain types of existing stationary sources of air pollutants install best... CFR 81.401 through 81.437, and you can find a map of the Class I areas at the following Internet...

  13. 40 CFR Appendix Y to Part 51 - Guidelines for BART Determinations Under the Regional Haze Rule

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... regional haze rule is found in this part at 40 CFR 51.300 through 51.309. These regulations require, in 40 CFR 51.308(e), that certain types of existing stationary sources of air pollutants install best... CFR 81.401 through 81.437, and you can find a map of the Class I areas at the following Internet...

  14. Windblown soil crust formation under light rainfall in a semiarid region

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many soils in arid and semi-arid regions of the world are affected by crusting, the process of forming a compact layer or thin mantle of consolidated material at the soil surface. Our objective was to evaluate the effect of rainfall quantity on crust formation of five soil types prominent in the Col...

  15. 40 CFR Appendix Y to Part 51 - Guidelines for BART Determinations Under the Regional Haze Rule

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... regional haze rule is found in this part at 40 CFR 51.300 through 51.309. These regulations require, in 40 CFR 51.308(e), that certain types of existing stationary sources of air pollutants install best... CFR 81.401 through 81.437, and you can find a map of the Class I areas at the following Internet...

  16. Biomass Studies in Monsoon Regions Under the Coordinated Enhanced Observing Period (CEOP)

    NASA Technical Reports Server (NTRS)

    Lau, William K. M.

    2003-01-01

    CEOP is an international program sponsored by the World Climate Research Project (WCRP) aiming at an integrated approach towards better understanding and prediction of the global water cycle. I will discuss the scientific rationale and approach that underpin the program, especially with regard to the important implications on variability of climate and rainfall in monsoon regions around the world.

  17. Response to selection under controlled environment versus natural selection in diverse regions across Canada

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Red clover is a widely adaptable and productive forage legume species found in most temperate regions of the world. To date, specific selection techniques for identifying genotypes with superior persistence have not been successful in improving the general adaptation and the long-term persistence o...

  18. Progeny of Osmia lignaria from distinct regions differ in developmental phenology and survival under a common thermal regime.

    PubMed

    Pitts-Singer, Theresa L; Cane, James H; Trostle, Glen

    2014-08-01

    Many insects, including some bees, have extensive subcontinental distributions that can differ in climatic conditions. Within and beyond these distributions, humans intentionally transport beneficial insects, including bees, to non-natal geographic locations. Insects also are experiencing unprecedented climatic change in their resident localities. For solitary bees, we know very little about the adaptive plasticity and geographic variation in developmental physiology that accommodates the different climates experienced within distributional ranges. Osmia lignaria Say (Hymenoptera: Megachilidae) is a widely distributed North American spring-emerging bee being developed as a managed pollinator for tree fruit crops, including almonds. We examined the development and survival of O. lignaria progeny that were descended from populations sourced from southern California, western Washington, and northern Utah, and then were reared together under an hourly and weekly temperature regime simulating those of a California almond-growing region. We found that developmental physiologies of Washington and Utah progeny were generally similar. However, California progeny developed slower, were more metabolically active, and survived better under California conditions than did populations native to regions at higher latitudes. Regardless of geographic origin, cocooned adults managed under prescribed thermal regimes emerged faster and lived longer after wintering. Progeny of parents from different regions exhibited some acclimatory plasticity in developmental phenologies to a novel climatic regime, but overall their responses reflected their geographic origins. This outcome is consistent with their developmental phenologies being largely heritable adaptations to regional climates. PMID:24879969

  19. Real-time optical diagnosis of the rat brain exposed to a laser-induced shock wave: observation of spreading depolarization, vasoconstriction and hypoxemia-oligemia.

    PubMed

    Sato, Shunichi; Kawauchi, Satoko; Okuda, Wataru; Nishidate, Izumi; Nawashiro, Hiroshi; Tsumatori, Gentaro

    2014-01-01

    Despite many efforts, the pathophysiology and mechanism of blast-induced traumatic brain injury (bTBI) have not yet been elucidated, partially due to the difficulty of real-time diagnosis and extremely complex factors determining the outcome. In this study, we topically applied a laser-induced shock wave (LISW) to the rat brain through the skull, for which real-time measurements of optical diffuse reflectance and electroencephalogram (EEG) were performed. Even under conditions showing no clear changes in systemic physiological parameters, the brain showed a drastic light scattering change accompanied by EEG suppression, which indicated the occurrence of spreading depression, long-lasting hypoxemia and signal change indicating mitochondrial energy impairment. Under the standard LISW conditions examined, hemorrhage and contusion were not apparent in the cortex. To investigate events associated with spreading depression, measurement of direct current (DC) potential, light scattering imaging and stereomicroscopic observation of blood vessels were also conducted for the brain. After LISW application, we observed a distinct negative shift in the DC potential, which temporally coincided with the transit of a light scattering wave, showing the occurrence of spreading depolarization and concomitant change in light scattering. Blood vessels in the brain surface initially showed vasodilatation for 3-4 min, which was followed by long-lasting vasoconstriction, corresponding to hypoxemia. Computer simulation based on the inverse Monte Carlo method showed that hemoglobin oxygen saturation declined to as low as ∼35% in the long-term hypoxemic phase. Overall, we found that topical application of a shock wave to the brain caused spreading depolarization/depression and prolonged severe hypoxemia-oligemia, which might lead to pathological conditions in the brain. Although further study is needed, our findings suggest that spreading depolarization/depression is one of the key events

  20. Real-Time Optical Diagnosis of the Rat Brain Exposed to a Laser-Induced Shock Wave: Observation of Spreading Depolarization, Vasoconstriction and Hypoxemia-Oligemia

    PubMed Central

    Sato, Shunichi; Kawauchi, Satoko; Okuda, Wataru; Nishidate, Izumi; Nawashiro, Hiroshi; Tsumatori, Gentaro

    2014-01-01

    Despite many efforts, the pathophysiology and mechanism of blast-induced traumatic brain injury (bTBI) have not yet been elucidated, partially due to the difficulty of real-time diagnosis and extremely complex factors determining the outcome. In this study, we topically applied a laser-induced shock wave (LISW) to the rat brain through the skull, for which real-time measurements of optical diffuse reflectance and electroencephalogram (EEG) were performed. Even under conditions showing no clear changes in systemic physiological parameters, the brain showed a drastic light scattering change accompanied by EEG suppression, which indicated the occurrence of spreading depression, long-lasting hypoxemia and signal change indicating mitochondrial energy impairment. Under the standard LISW conditions examined, hemorrhage and contusion were not apparent in the cortex. To investigate events associated with spreading depression, measurement of direct current (DC) potential, light scattering imaging and stereomicroscopic observation of blood vessels were also conducted for the brain. After LISW application, we observed a distinct negative shift in the DC potential, which temporally coincided with the transit of a light scattering wave, showing the occurrence of spreading depolarization and concomitant change in light scattering. Blood vessels in the brain surface initially showed vasodilatation for 3–4 min, which was followed by long-lasting vasoconstriction, corresponding to hypoxemia. Computer simulation based on the inverse Monte Carlo method showed that hemoglobin oxygen saturation declined to as low as ∼35% in the long-term hypoxemic phase. Overall, we found that topical application of a shock wave to the brain caused spreading depolarization/depression and prolonged severe hypoxemia-oligemia, which might lead to pathological conditions in the brain. Although further study is needed, our findings suggest that spreading depolarization/depression is one of the key

  1. Regional Climate and Streamflow Projections in North America Under IPCC CMIP5 Scenarios

    NASA Astrophysics Data System (ADS)

    Chang, H. I.; Castro, C. L.; Troch, P. A. A.; Mukherjee, R.

    2014-12-01

    The Colorado River system is the predominant source of water supply for the Southwest U.S. and is already fully allocated, making the region's environmental and economic health particularly sensitive to annual and multi-year streamflow variability. Observed streamflow declines in the Colorado Basin in recent years are likely due to synergistic combination of anthropogenic global warming and natural climate variability, which are creating an overall warmer and more extreme climate. IPCC assessment reports have projected warmer and drier conditions in arid to semi-arid regions (e.g. Solomon et al. 2007). The NAM-related precipitation contributes to substantial Colorado streamflows. Recent climate change studies for the Southwest U.S. region project a dire future, with chronic drought, and substantially reduced Colorado River flows. These regional effects reflect the general observation that climate is being more extreme globally, with areas climatologically favored to be wet getting wetter and areas favored to be dry getting drier (Wang et al. 2012). Multi-scale downscaling modeling experiments are designed using recent IPCC AR5 global climate projections, which incorporate regional climate and hydrologic modeling components. The Weather Research and Forecasting model (WRF) has been selected as the main regional modeling tool; the Variable Infiltration Capacity model (VIC) will be used to generate streamflow projections for the Colorado River Basin. The WRF domain is set up to follow the CORDEX-North America guideline with 25km grid spacing, and VIC model is individually calibrated for upper and lower Colorado River basins in 1/8° resolution. The multi-scale climate and hydrology study aims to characterize how the combination of climate change and natural climate variability is changing cool and warm season precipitation. Further, to preserve the downscaled RCM sensitivity and maintain a reasonable climatology mean based on observed record, a new bias correction

  2. Vertical gradients in the zonal wind observed in the equatorial F-region under postsunset conditions

    NASA Astrophysics Data System (ADS)

    Kiene, A.; Larsen, M. F.; Kudeki, E.

    2014-12-01

    In the early evening sector of the F region near the geomagnetic equator, an eastward pressure gradient as the sun sets reorients the neutral flow toward the east, typically occurring within one hour of local sunset. Very few vertically-resolved measurements of this effect exist. We present recent in-situ chemical tracer results from the EVEX campaign, as well as results from the earlier Guara campaign, that show strong vertical shear in the zonal wind during sunset hours in the F region, up to a 150 m/s westward shift over 60 km altitude. Eastward F-region neutral winds near the geomagnetic equator drive vertical Pedersen currents at sunset that, in turn, drive the prereversal enhancement (PRE) of the eastward electric field in the equatorial F-region that is thought to be a primary driver of equatorial spread-F. Studies of the neutral winds relating to the PRE have been primarily focused on the winds observed from ground-based interferometry and from satellite accelerometer data, techniques which generally lack vertical resolution. We show that eastward winds at one altitude are not necessarily accompanied by eastward winds at higher altitudes, i.e., that the forces that drive the neutral wind are not constant with altitude at sunset. At sunset, solar heating varies significantly with altitude, decreasing at lower altitudes first, which would create a thermal pressure gradient with a similar vertical profile to that observed in the neutral winds. We discuss the magnitude of this effect as well as other factors that could contribute to the observed vertical gradients. We then apply these effects to typical ionospheric conditions at the time of the experiments and examine the resulting neutral forcing in relation to the observed wind profiles.

  3. Agricultural pests under future climate conditions: downscaling of regional climate scenarios with a stochastic weather generator

    NASA Astrophysics Data System (ADS)

    Hirschi, M.; Stöckli, S.; Dubrovsky, M.; Spirig, C.; Rotach, M. W.; Calanca, P.; Samietz, J.

    2010-09-01

    As a consequence of current and projected climate change in temperate regions of Europe, agricultural pests and diseases are expected to occur more frequently and possibly to extend to previously unaffected regions. Given their economic and ecological relevance, detailed forecasting tools for various pests have been developed, which model the infestation depending on actual weather conditions. Assessing the future risk of pest-related damages therefore requires future weather data at high temporal and spatial resolution. In particular, pest forecast models are often not based on screen temperature and precipitation alone (i.e., the most generally projected climate variables), but might require input variables such as soil temperature, in-canopy net radiation or leaf wetness. Here, we use a stochastic weather and a re-sampling procedure for producing site-specific hourly weather data from regional climate change scenarios for 2050 in Switzerland. The climate change scenarios were derived from multi-model projections and provide probabilistic information on future regional changes in temperature and precipitation. Hourly temperature, precipitation and radiation data were produced by first generating daily weather data for these climate scenarios and then using a nearest neighbor re-sampling approach for creating realistic diurnal cycles. These hourly weather time series were then used for modeling important phases in the lifecycle of codling moth, the major insect pest in apple orchards worldwide. First results indicate a shift in the occurrence and duration of phases relevant for pest disease control for projected as compared to current climate (e.g. the flight of the codling moth starts about ten days earlier in future climate), continuing an already observed trend towards more favorable conditions for this insect during the last 20 years.

  4. Regional modeling of large wildfires under current and potential future climates in Colorado and Wyoming, USA

    USGS Publications Warehouse

    West, Amanda; Kumar, Sunil; Jarnevich, Catherine S.

    2016-01-01

    Regional analysis of large wildfire potential given climate change scenarios is crucial to understanding areas most at risk in the future, yet wildfire models are not often developed and tested at this spatial scale. We fit three historical climate suitability models for large wildfires (i.e. ≥ 400 ha) in Colorado andWyoming using topography and decadal climate averages corresponding to wildfire occurrence at the same temporal scale. The historical models classified points of known large wildfire occurrence with high accuracies. Using a novel approach in wildfire modeling, we applied the historical models to independent climate and wildfire datasets, and the resulting sensitivities were 0.75, 0.81, and 0.83 for Maxent, Generalized Linear, and Multivariate Adaptive Regression Splines, respectively. We projected the historic models into future climate space using data from 15 global circulation models and two representative concentration pathway scenarios. Maps from these geospatial analyses can be used to evaluate the changing spatial distribution of climate suitability of large wildfires in these states. April relative humidity was the most important covariate in all models, providing insight to the climate space of large wildfires in this region. These methods incorporate monthly and seasonal climate averages at a spatial resolution relevant to land management (i.e. 1 km2) and provide a tool that can be modified for other regions of North America, or adapted for other parts of the world.

  5. Regional to global changes in drought and implications for future changes under global warming

    NASA Astrophysics Data System (ADS)

    Sheffield, J.; Wood, E. F.; Kam, J.

    2012-12-01

    Drought can have large impacts on multiple sectors, including agriculture, water resources, ecosystems, transport, industry and tourism. In extreme cases, regional drought can lead to food insecurity and famine, and in intensive agricultural regions, extend to global economic impacts in a connected world. Recent droughts globally have been severe and costly but whether they are becoming more frequent and severe, and the attribution of this, is a key question. Observational evidence at large scales, such as satellite remote sensing are often subject to short-term records and inhomogeneities, and ground based data are sparse in many regions. Reliance on model output is also subject to error and simplifications in the model physics that can, for example, amplify the impact of global warming on drought. This presentation will show the observational and model evidence for changes in drought, with a focus on the interplay between precipitation and atmospheric evaporative demand and its impact on the terrestrial water cycle and drought. We discuss the fidelity of climate models to reproduce our best estimates of drought variability and its drivers historically, and the implications of this on uncertainties in future projections of drought from CMIP5 models, and how this has changed since CMIP3.

  6. A fluorescence XAFS measurement instrument in the soft x-ray region toward observation under operando conditions

    SciTech Connect

    Honda, M. Baba, Y.; Shimoyama, I.; Sekiguchi, T.

    2015-03-15

    X-ray absorption fine structure (XAFS) measurements are widely used for the analysis of electronic structure. Generally, XAFS in the soft X-ray region is measured under vacuum, but chemical structures under vacuum are typically different from those under operando conditions, where chemical species exhibit their function. Here, we developed an XAFS measurement instrument, as a step toward operando fluorescent, which yields XAFS measurement using synchrotron radiation in the soft X-ray region. We applied this method to analyze the local electronic structure of the sulfur atoms in L-cysteine in different pH solutions. In water at pH 7, the hydrogen atom does not dissociate from the thiol (-SH) group in L-cysteine, which forms a structure surrounded by and interacting with water molecules. The XAFS spectrum of L-cysteine in solution was altered by changing the pH. At pH 9, the hydrogen atom dissociated and a thiolate anion was formed. Although the -SH group was oxidized to SO{sub 4}{sup 2−} when L-cysteine was adsorbed on a metal surface and dried, no oxidation was observed in solution. This may be because the water molecules were densely packed and protected the -SH group from oxidation. Our results show that this instrument aimed toward operando fluorescence XAFS measurements in the soft X-ray region is useful for structural analysis of sulfur atoms in organic molecules in air and in solution. The instrument will be applied to the structural analysis of materials containing elements that have absorption edges in soft X-ray region, such as phosphorus and alkali metals (potassium and cesium). It will be also particularly useful for the analysis of samples that are difficult to handle under vacuum and materials that have specific functions in solution.

  7. A fluorescence XAFS measurement instrument in the soft X-ray region toward observation under operando conditions.

    PubMed

    Honda, M; Baba, Y; Shimoyama, I; Sekiguchi, T

    2015-03-01

    X-ray absorption fine structure (XAFS) measurements are widely used for the analysis of electronic structure. Generally, XAFS in the soft X-ray region is measured under vacuum, but chemical structures under vacuum are typically different from those under operando conditions, where chemical species exhibit their function. Here, we developed an XAFS measurement instrument, as a step toward operando fluorescent, which yields XAFS measurement using synchrotron radiation in the soft X-ray region. We applied this method to analyze the local electronic structure of the sulfur atoms in L-cysteine in different pH solutions. In water at pH 7, the hydrogen atom does not dissociate from the thiol (-SH) group in L-cysteine, which forms a structure surrounded by and interacting with water molecules. The XAFS spectrum of L-cysteine in solution was altered by changing the pH. At pH 9, the hydrogen atom dissociated and a thiolate anion was formed. Although the -SH group was oxidized to SO4 (2-) when L-cysteine was adsorbed on a metal surface and dried, no oxidation was observed in solution. This may be because the water molecules were densely packed and protected the -SH group from oxidation. Our results show that this instrument aimed toward operando fluorescence XAFS measurements in the soft X-ray region is useful for structural analysis of sulfur atoms in organic molecules in air and in solution. The instrument will be applied to the structural analysis of materials containing elements that have absorption edges in soft X-ray region, such as phosphorus and alkali metals (potassium and cesium). It will be also particularly useful for the analysis of samples that are difficult to handle under vacuum and materials that have specific functions in solution. PMID:25832271

  8. A fluorescence XAFS measurement instrument in the soft x-ray region toward observation under operando conditions

    NASA Astrophysics Data System (ADS)

    Honda, M.; Baba, Y.; Shimoyama, I.; Sekiguchi, T.

    2015-03-01

    X-ray absorption fine structure (XAFS) measurements are widely used for the analysis of electronic structure. Generally, XAFS in the soft X-ray region is measured under vacuum, but chemical structures under vacuum are typically different from those under operando conditions, where chemical species exhibit their function. Here, we developed an XAFS measurement instrument, as a step toward operando fluorescent, which yields XAFS measurement using synchrotron radiation in the soft X-ray region. We applied this method to analyze the local electronic structure of the sulfur atoms in L-cysteine in different pH solutions. In water at pH 7, the hydrogen atom does not dissociate from the thiol (-SH) group in L-cysteine, which forms a structure surrounded by and interacting with water molecules. The XAFS spectrum of L-cysteine in solution was altered by changing the pH. At pH 9, the hydrogen atom dissociated and a thiolate anion was formed. Although the -SH group was oxidized to SO42- when L-cysteine was adsorbed on a metal surface and dried, no oxidation was observed in solution. This may be because the water molecules were densely packed and protected the -SH group from oxidation. Our results show that this instrument aimed toward operando fluorescence XAFS measurements in the soft X-ray region is useful for structural analysis of sulfur atoms in organic molecules in air and in solution. The instrument will be applied to the structural analysis of materials containing elements that have absorption edges in soft X-ray region, such as phosphorus and alkali metals (potassium and cesium). It will be also particularly useful for the analysis of samples that are difficult to handle under vacuum and materials that have specific functions in solution.

  9. Deriving plasma densities in tenuous plasma regions, with the spacecraft potential under active control

    NASA Astrophysics Data System (ADS)

    Andriopoulou, M.; Nakamura, R.; Torkar, K.; Baumjohann, W.; Hoelzl, B.

    2015-11-01

    Variations of the floating potential on spacecraft are often used to derive plasma densities, complementing the plasma instrument measurements. All spacecraft of the Cluster mission are equipped with Active Spacecraft POtential Control (ASPOC) instruments that control the spacecraft potential. Although the ASPOC operation increases the accuracy of electric field and plasma measurements, it prevents a direct use of the spacecraft potential variations to derive plasma densities. In this work we develop a new reconstruction method of uncontrolled spacecraft potential from controlled spacecraft potential data and a derived photoelectron curve, using multispacecraft observations. We assume that the same curve governs the plasma environment for the spacecraft with ASPOC on and off. The current work focuses on reconstructions in the magnetotail region. The period that was more extensively studied was the one from August to October 2003, when the spacecraft were close to each other, while results from the periods of August-October 2001, 2002, and 2004, when the Cluster spacecraft had their apogee in the magnetotail region, are also presented. In this way, we investigate how the photoelectron curve varies at different time intervals and also how the reconstruction results are modified when the distance between the spacecraft is increasing. Finally, by using the reconstructed results, we proceed by estimating the plasma densities and we discuss the uncertainties of such estimations. While, on average, spacecraft potential measurements are successfully reconstructed, plasma and solar activity variations on short timescales seem to affect the reconstructions, requiring in some cases more detailed analysis in order to achieve results with higher accuracy. Moreover, there are some limitations while deriving results in very tenuous plasma regions due to increased uncertainties in some of the scientific measurements used there. The results and the methods developed for this work

  10. Soil functioning in an agroextractivist system in the Eastern Amazon region under family farming management

    NASA Astrophysics Data System (ADS)

    Fernanda Simões da Silva, Laura; Nascimento Delgado Oliveira, Mariana; de Pierri Castilho, Selene Cristina; Cooper, Miguel

    2014-05-01

    Family farming has been identified as a major modifier of Amazonian vegetation cover. These small establishments have had problems with the availability of water resources, soil quality and, consequently, low crop production. Amazonian soils studies have generated data that make up a database about the changing soil conditions as a result of the land use modifications. The objective of this research is to understand the soil degradation processes that occur on two toposequences, under native forest and pasture, in a family farming establishment. The study area is located in the Piranheira Praialta Agroextrativist Settlement Project in the county of Nova Ipixuna, Pará, Brazil. Two toposequences were chosen, one under native forest and the other under pasture. Pits were opened in different landscape positions (upslope, midslope and downslope) for soil morphological, micromorphological and physical characterization. Samples were taken for soil particle distribution, bulk density, particle density, hydraulic conductivity and image analysis. The soils were classified according to World Reference Base (WRB-FAO, 2006) as Plinthic Acrisol Clayic, Haplic Cambisols Dystric Skeletic and Haplic Plinthosol Clayic Dystric. The results show that all the studied profiles presented higher contents of sand in the surface horizons and an increase in clay in the subsurface horizons. This indicates heterogeneity of the particle soil distribution in the soil profiles along the different landscape positions. Higher bulk density values are found in the surface horizons due to the sandy texture of these horizons. Under forest, soil bulk density varies from 1,260 to 1,580 Mg m3, and under pasture bulk densities were higher varying from 1,270 to 1,710 Mg m3. Soil particle density results obtained in both land use systems were very similar in all horizons varying from 2,580 to 2,630 Mg m3 under forest and from 2,580 to 2,670 under pasture. Image analysis results showed a significant decrease

  11. An inexact stochastic-fuzzy jointed chance-constrained programming for regional energy system management under uncertainty

    NASA Astrophysics Data System (ADS)

    Liu, Zhengping; Huang, Guohe; Li, Wei

    2015-06-01

    Environmental problems associated with socio-economic development have been a growing concern facing many regional and/or national authorities. However, effective planning may encounter difficulties since uncertainties existing in a number of impact factors and pollution-related processes are often not well acknowledged and reflected. Combining chance-constrained programming and fuzzy credibility-constrained programming with interval parameters and stochastic programming, this study advances an inexact stochastic-fuzzy jointed chance-constrained programming method for planning regional economic and environmental systems under multiple uncertainties presented as intervals, fuzzy sets and probability distributions. The developed method has been applied to a case of long-term energy management system with multiple energy resources and three communities. Emissions of sulphur dioxide and nitrogen oxides are controlled and capacity expansion is scheduled. The results can help to identify desired alternatives for planning regional development strategies, where compromised schemes are provided under an integrated consideration of economic efficiency and environmental protection under multiple uncertainties.

  12. Agricultural water supply/demand changes under projected future climate change in the arid region of northwestern China

    NASA Astrophysics Data System (ADS)

    Guo, Ying; Shen, Yanjun

    2016-09-01

    The water resources in the arid region of northwestern China, which are impacted by climate change, tend to be more unstable, and the environment and ecosystems will suffer from severe water shortage. In this paper, potential future climate trends were predicted based on CMIP5 simulations in this region. The water availability and agricultural water demand under future climate change scenarios were estimated. Impacted by increases in temperature, the irrigation water demand will increase by 4.27-6.15 billion m3 in this region over the next 60 years, compared to the demand of 32.75 billion m3 during 1971-2000. However, the annual runoff will only increase by 4.8-8.5 billion m3, which is equivalent to or even less than the increased irrigation water demand. In fact, the increased demand for industrial, domestic and ecological water were not considered here. Thus, the water supply/demand contradiction will result in more severe water shortages in the future. According to a comparison with simulated irrigation water demand under three adaptation strategy scenarios, we should take effective measures such as improving the efficiency of irrigation water utilization, reducing crop planting areas and adjusting crop planting structures to alleviate the impacts of future climate changes and human activities on the water supply and water use in this region.

  13. Heparin inhibits Angiotensin II-induced vasoconstriction on isolated mouse mesenteric resistance arteries through Rho-A- and PKA-dependent pathways

    PubMed Central

    Xie-Zukauskas, Hui; Das, Jharna; Short, Billie Lou; Gutkind, J. Silvio; Ray, Patricio E.

    2013-01-01

    Heparin is commonly used to treat intravascular thrombosis in children undergoing extracorporeal membrane oxygenation or cardiopulmonary bypass. These clinical circumstances are associated with elevated plasma levels of angiotensin II (Ang II). However, the mechanisms by which heparin modulates vascular reactivity of Ang II remain unclear. We hypothesized that heparin may offset Ang II-induced vasoconstriction on mesenteric resistances arteries through modulating the Rho-A/Rho kinase pathway. Vascular contractility was studied using pressurized, resistance-sized mesenteric arteries from mice. Rho-A activation was measured by pull-down assay, and myosin light chain or PKA phosphorylation by immunoblotting. We found that heparin significantly attenuated vasoconstriction induced by Ang II but not that by KCl. The combined effect of Ang II with heparin was almost abolished by a specific Rho kinase inhibitor Y27632. Ang II stimulated Rho-A activation and myosin light chain phosphorylation, both responses were antagonized by heparin. Moreover, the inhibitory effect of heparin on Ang II-induced vasoconstriction was reversed by Rp-cAMPS (cAMP-dependent PKA inhibitor), blunted by ODQ (soluble guanylate cyclase inhibitor), and mimicked by a cell-permeable cGMP analogue, 8-Br-cGMP, but not by a cAMP analogue. PKC and Src kinase were not involved. We conclude that heparin inhibits Ang II-induced vasoconstriction through Rho-A/Rho kinase- and cGMP/PKA-dependent pathways. PMID:23268358

  14. Systems-Based Analyses of Brain Regions Functionally Impacted in Parkinson's Disease Reveals Underlying Causal Mechanisms

    PubMed Central

    Emig-Agius, Dorothea; Bessarabova, Marina; Ivliev, Alexander E.; Schüle, Birgit; Alexander, Jeff; Wallace, William; Halliday, Glenda M.; Langston, J. William; Braxton, Scott; Yednock, Ted; Shaler, Thomas; Johnston, Jennifer A.

    2014-01-01

    Detailed analysis of disease-affected tissue provides insight into molecular mechanisms contributing to pathogenesis. Substantia nigra, striatum, and cortex are functionally connected with increasing degrees of alpha-synuclein pathology in Parkinson's disease. We undertook functional and causal pathway analysis of gene expression and proteomic alterations in these three regions, and the data revealed pathways that correlated with disease progression. In addition, microarray and RNAseq experiments revealed previously unidentified causal changes related to oligodendrocyte function and synaptic vesicle release, and these and other changes were reflected across all brain regions. Importantly, subsets of these changes were replicated in Parkinson's disease blood; suggesting peripheral tissue may provide important avenues for understanding and measuring disease status and progression. Proteomic assessment revealed alterations in mitochondria and vesicular transport proteins that preceded gene expression changes indicating defects in translation and/or protein turnover. Our combined approach of proteomics, RNAseq and microarray analyses provides a comprehensive view of the molecular changes that accompany functional loss and alpha-synuclein pathology in Parkinson's disease, and may be instrumental to understand, diagnose and follow Parkinson's disease progression. PMID:25170892

  15. Assimilation of thermodynamic information from advanced infrared sounders under partially cloudy skies for regional NWP

    NASA Astrophysics Data System (ADS)

    Wang, Pei; Li, Jun; Goldberg, Mitchell D.; Schmit, Timothy J.; Lim, Agnes H. N.; Li, Zhenglong; Han, Hyojin; Li, Jinlong; Ackerman, Steve A.

    2015-06-01

    Generally, only clear-infrared spectral radiances (not affected by clouds) are assimilated in weather analysis systems. This is due to difficulties in modeling cloudy radiances as well as in observing their vertical structure from space. To take full advantage of the thermodynamic information in advanced infrared (IR) sounder observations requires assimilating radiances from cloud-contaminated regions. An optimal imager/sounder cloud-clearing technique has been developed by the Cooperative Institute for Meteorological Satellite Studies at the University of Wisconsin-Madison. This technique can be used to retrieve clear column radiances through combining collocated multiband imager IR clear radiances and the sounder cloudy radiances; no background information is needed in this method. The imager/sounder cloud-clearing technique is similar to that of the microwave/IR cloud clearing in the derivation of the clear-sky equivalent radiances. However, it retains the original IR sounder resolution, which is critical for regional numerical weather prediction applications. In this study, we have investigated the assimilation of cloud-cleared IR sounder radiances using Atmospheric Infrared Sounder (AIRS)/Moderate Resolution Imaging Spectroradiometer for three hurricanes, Sandy (2012), Irene (2011), and Ike (2008). Results show that assimilating additional cloud-cleared AIRS radiances reduces the 48 and 72 h temperature forecast root-mean-square error by 0.1-0.3 K between 300 and 850 hPa. Substantial improvement in reducing track forecasts errors in the range of 10 km to 50 km was achieved.

  16. Effect of PDE5 inhibition on the modulation of sympathetic α-adrenergic vasoconstriction in contracting skeletal muscle of young and older recreationally active humans.

    PubMed

    Nyberg, Michael; Piil, Peter; Egelund, Jon; Sprague, Randy S; Mortensen, Stefan P; Hellsten, Ylva

    2015-12-01

    Aging is associated with an altered regulation of blood flow to contracting skeletal muscle; however, the precise mechanisms remain unclear. We recently demonstrated that inhibition of cGMP-binding phosphodiesterase 5 (PDE5) increased blood flow to contracting skeletal muscle of older but not young human subjects. Here we examined whether this effect of PDE5 inhibition was related to an improved ability to blunt α-adrenergic vasoconstriction (functional sympatholysis) and/or improved efficacy of local vasodilator pathways. A group of young (23 ± 1 yr) and a group of older (72 ± 1 yr) male subjects performed knee-extensor exercise in a control setting and following intake of the highly selective PDE5 inhibitor sildenafil. During both conditions, exercise was performed without and with arterial tyramine infusion to evoke endogenous norepinephrine release and consequently stimulation of α1- and α2-adrenergic receptors. The level of the sympatholytic compound ATP was measured in venous plasma by use of the microdialysis technique. Sildenafil increased (P < 0.05) vascular conductance during exercise in the older group, but tyramine infusion reduced (P < 0.05) this effect by 38 ± 9%. Similarly, tyramine reduced (P < 0.05) the vasodilation induced by arterial infusion of a nitric oxide (NO) donor by 54 ± 9% in the older group, and this effect was not altered by sildenafil. Venous plasma [ATP] did not change with PDE5 inhibition in the older subjects during exercise. Collectively, PDE5 inhibition in older humans was not associated with an improved ability for functional sympatholysis. An improved efficacy of the NO system may be one mechanism underlying the effect of PDE5 inhibition on exercise hyperemia in aging. PMID:26432842

  17. Quinidine, but Not Eicosanoid Antagonists or Dexamethasone, Protect the Gut from Platelet Activating Factor-Induced Vasoconstriction, Edema and Paralysis

    PubMed Central

    Lautenschläger, Ingmar; Frerichs, Inéz; Dombrowsky, Heike; Sarau, Jürgen; Goldmann, Torsten; Zitta, Karina; Albrecht, Martin; Weiler, Norbert; Uhlig, Stefan

    2015-01-01

    Intestinal circulatory disturbances, atony, edema and swelling are of great clinical relevance, but the related mechanisms and possible therapeutic options are poorly characterized, in part because of the difficulties to comprehensively analyze these conditions. To overcome these limitations we have developed a model of the isolated perfused rat small intestine where all of these symptoms can be studied simultaneously. Here we used this model to study the role of eicosanoids, steroids and quinidine in platelet-activating factor (PAF)-induced intestinal disorders. A vascular bolus of PAF (0.5 nmol) triggered release of thromboxane and peptidoleukotrienes into the vascular bed (peak concentration 35 nM and 0.8 nM) and reproduced all symptoms of intestinal failure: mesenteric vasoconstriction, translocation of fluid and macromolecules from the vasculature to the lumen and lymphatics, intestinal edema formation, loss of intestinal peristalsis and decreased galactose uptake. All effects of PAF were abolished by the PAF-receptor antagonist ABT491 (2.5 μM). The COX and LOX inhibitors ASA and AA861 (500 μM, 10 μM) did not exhibit barrier-protective effects and the eicosanoid antagonists SQ29548 and MK571 (10 μM, each) only moderately attenuated the loss of vascular fluid, the redistribution to the lumen and the transfer of FITC dextran to the lumen. The steroid dexamethasone (10 μM) showed no barrier-protective properties and failed to prevent edema formation. Quinidine (100 μM) inhibited the increase in arterial pressure, stabilized all the intestinal barriers, and reduced lymph production and the transfer of FITC dextran to the lymph. While quinidine by itself reduced peristalsis, it also obviated paralysis, preserved intestinal functions and prevented edema formation. We conclude that quinidine exerts multiple protective effects against vasoconstriction, edema formation and paralysis in the intestine. The therapeutic use of quinidine for intestinal ailments

  18. Quinidine, but not eicosanoid antagonists or dexamethasone, protect the gut from platelet activating factor-induced vasoconstriction, edema and paralysis.

    PubMed

    Lautenschläger, Ingmar; Frerichs, Inéz; Dombrowsky, Heike; Sarau, Jürgen; Goldmann, Torsten; Zitta, Karina; Albrecht, Martin; Weiler, Norbert; Uhlig, Stefan

    2015-01-01

    Intestinal circulatory disturbances, atony, edema and swelling are of great clinical relevance, but the related mechanisms and possible therapeutic options are poorly characterized, in part because of the difficulties to comprehensively analyze these conditions. To overcome these limitations we have developed a model of the isolated perfused rat small intestine where all of these symptoms can be studied simultaneously. Here we used this model to study the role of eicosanoids, steroids and quinidine in platelet-activating factor (PAF)-induced intestinal disorders. A vascular bolus of PAF (0.5 nmol) triggered release of thromboxane and peptidoleukotrienes into the vascular bed (peak concentration 35 nM and 0.8 nM) and reproduced all symptoms of intestinal failure: mesenteric vasoconstriction, translocation of fluid and macromolecules from the vasculature to the lumen and lymphatics, intestinal edema formation, loss of intestinal peristalsis and decreased galactose uptake. All effects of PAF were abolished by the PAF-receptor antagonist ABT491 (2.5 μM). The COX and LOX inhibitors ASA and AA861 (500 μM, 10 μM) did not exhibit barrier-protective effects and the eicosanoid antagonists SQ29548 and MK571 (10 μM, each) only moderately attenuated the loss of vascular fluid, the redistribution to the lumen and the transfer of FITC dextran to the lumen. The steroid dexamethasone (10 μM) showed no barrier-protective properties and failed to prevent edema formation. Quinidine (100 μM) inhibited the increase in arterial pressure, stabilized all the intestinal barriers, and reduced lymph production and the transfer of FITC dextran to the lymph. While quinidine by itself reduced peristalsis, it also obviated paralysis, preserved intestinal functions and prevented edema formation. We conclude that quinidine exerts multiple protective effects against vasoconstriction, edema formation and paralysis in the intestine. The therapeutic use of quinidine for intestinal ailments

  19. Direct sGC Activation Bypasses NO Scavenging Reactions of Intravascular Free Oxy-Hemoglobin and Limits Vasoconstriction

    PubMed Central

    Tabima, D. Marcela; Specht, Patricia A.C.; Tejero, Jesús; Champion, Hunter C.; Kim-Shapiro, Daniel B.; Baust, Jeff; Mik, Egbert G.; Hildesheim, Mariana; Stasch, Johannes-Peter; Becker, Eva-Maria; Truebel, Hubert

    2013-01-01

    Abstract Aims: Hemoglobin-based oxygen carriers (HBOC) provide a potential alternative to red blood cell (RBC) transfusion. Their clinical application has been limited by adverse effects, in large part thought to be mediated by the intravascular scavenging of the vasodilator nitric oxide (NO) by cell-free plasma oxy-hemoglobin. Free hemoglobin may also cause endothelial dysfunction and platelet activation in hemolytic diseases and after transfusion of aged stored RBCs. The new soluble guanylate cyclase (sGC) stimulator Bay 41-8543 and sGC activator Bay 60-2770 directly modulate sGC, independent of NO bioavailability, providing a potential therapeutic mechanism to bypass hemoglobin-mediated NO inactivation. Results: Infusions of human hemoglobin solutions and the HBOC Oxyglobin into rats produced a severe hypertensive response, even at low plasma heme concentrations approaching 10 μM. These reactions were only observed for ferrous oxy-hemoglobin and not analogs that do not rapidly scavenge NO. Infusions of L-NG-Nitroarginine methyl ester (L-NAME), a competitive NO synthase inhibitor, after hemoglobin infusion did not produce additive vasoconstriction, suggesting that vasoconstriction is related to scavenging of vascular NO. Open-chest hemodynamic studies confirmed that hypertension occurred secondary to direct effects on increasing vascular resistance, with limited negative cardiac inotropic effects. Intravascular hemoglobin reduced the vasodilatory potency of sodium nitroprusside (SNP) and sildenafil, but had no effect on vasodilatation by direct NO-independent activation of sGC by BAY 41-8543 and BAY 60-2770. Innovation and Conclusion: These data suggest that both sGC stimulators and sGC activators could be used to restore cyclic guanosine monophosphate-dependent vasodilation in conditions where cell-free plasma hemoglobin is sufficient to inhibit endogenous NO signaling. Antioxid. Redox Signal. 19, 2232–2243. PMID:23697678

  20. [Prediction and simulation of urban area expansion in Pearl River Delta Region under the RCPs climate scenarios].

    PubMed

    Jiang, Oun-ou; Deng, Xiang-zheng; Ke, Xin-li; Zhao, Chun-hong; Zhang, Wei

    2014-12-01

    The sizes and number of cities in China are increasing rapidly and complicated changes of urban land use system have occurred as the social economy develops rapidly. This study took the urban agglomeration of Pearl River Delta Region as the study area to explore the driving mechanism of dynamic changes of urban area in the urbanization process under the joint influence of natural environment and social economic conditions. Then the CA (cellular automata) model was used to predict and simulate the urban area changes until 2030 under the designed scenarios of planning and RCPs (representative concentration pathways). The results indicated that urbanization was mainly driven by the non-agricultural population growth and social-economic development, and the transportation had played a fundamental role in the whole process, while the areas with high elevation or steep slope restricted the urbanization. Besides, the urban area would keep an expanding trend regardless of the scenarios, however, the expanding speed would slow down with different inflection points under different scenarios. The urban expansion speed increased in the sequence of the planning scenario, MESSAGE scenario and AIM scenario, and that under the MESSAGE climate scenario was more consistent with the current urban development trend. In addition, the urban expansion would mainly concentrate in regions with the relatively high urbanization level, e.g., Guangzhou, Dongguan, Foshan, Shenzhen, Zhanjiang and Chaoshan. PMID:25876417

  1. Adult activity and temperature preference drives region-wide damselfly (Zygoptera) distributions under a warming climate

    PubMed Central

    Corser, Jeffrey D.; White, Erin L.; Schlesinger, Matthew D.

    2015-01-01

    We analysed a recently completed statewide odonate Atlas using multivariate linear models. Within a phylogenetically explicit framework, we developed a suite of data-derived traits to assess the mechanistic distributional drivers of 59 species of damselflies in New York State (NYS). We found that length of the flight season (adult breeding activity period) mediated by thermal preference drives regional distributions at broad (105 km2) scales. Species that had longer adult flight periods, in conjunction with longer growing seasons, had significantly wider distributions. These intrinsic traits shape species' responses to changing climates and the mechanisms behind such range shifts are fitness-based metapopulation processes that adjust phenology to the prevailing habitat and climate regime through a photoperiod filter. PMID:25878048

  2. European air pollution in 2050, a regional air quality and climate perspective under CMIP5 scenarios

    NASA Astrophysics Data System (ADS)

    Colette, A.; Bessagnet, B.; Vautard, R.; Szopa, S.; Rao, S.; Schucht, S.; Klimont, Z.; Holland, M.; Menut, L.; Meleux, F.; Rouïl, L.

    2013-12-01

    Air pollution and climate change are closely related. They share both driving geophysical processes and mitigation strategies. Increased temperature, changes in weather regimes and precipitation patterns will alter the formation of pollution episodes. At the same time curbing greenhouse gases emission will also induce indirect co-benefits for air pollutant emissions. As a consequence, understanding the long-term efficiency of air pollution mitigation strategies requires the integrated implementation of comprehensive geophysical and economical models. Coupling air pollution and climate models for long term projections raise a number of scientific and technical issues. Global scale circulation outputs must be downscaled in order to provide high resolution three dimensional meteorological fields at high temporal frequency to the chemistry transport model. The computational cost of the air quality model is comparable to the cost of the regional climate model. So that the computing demand and storage call for an efficient design of a complex modelling suite. Moreover the cost of the project prohibits the implementation of large ensemble of model, thereby raising concerns on the treatment of uncertainty analyses of the projections. We present an integrated assessment of future air quality that relies on up-to-date emission scenarios and full-frame geophysical models of climate and atmospheric chemistry which are themselves embedded in monetised economical models to propose a cost-benefit assessment. Emissions: For long lived trace species, we use the Representative Concentrations Pathways (RCP) produced for the Fifth Assessment Report (AR5) of IPCC whereas regional air quality modelling is based on the updated emissions scenarios produced in the framework of the Global Energy Assessment (GEA) that offer an explicit representation of air quality policies. Climate and chemistry models: We use the latest sources of recent coordinated model intercomparison projects, each

  3. Use of wetlands under USEPA's (Environmental Protection Agency's) Region 5 Clean Lakes Program. Master's thesis

    SciTech Connect

    Landers, J.C.

    1989-05-01

    The EPA's Region V Clean Lakes Program uses several wetlands for controlling degradation of publicly owned, freshwater lakes. The study seeks to determine if the objectives of the Clean Lakes Program are being met by this use of wetlands, and if appropriate institutional arrangements and management techniques are being implemented to manage the wetlands. Conclusions regarding Revion V's use and management of wetlands include: wetland projects are not being monitored adequately for effectiveness and potential negative impacts on ecosystems; other mechanisms which may help to protect wetlands are being employed; management of most wetland projects is decentralized appropriately; most of the wetland projects provide for adequate short-term mass balance studies, prior sedimentation, plant species diversity, water level, retention time, uniform flow of water, and upland pollutant management; and existing evidence suggests that the Clean Lakes wetland projects are instrumental in meeting Program goals and objectives. Based on these conclusions several recommendations for improving wetlands management are reviewed.

  4. Hi-C Observations of an Active Region Corona, and Investigation of the Underlying Magnetic Structure

    NASA Technical Reports Server (NTRS)

    Tiwari, S. K.; Alexander, C. E.; Winebarger, A.; Moore, R. L.

    2014-01-01

    The solar corona is much hotter (>=10(exp 6) K) than its surface (approx 6000 K), puzzling astrophysicists for several decades. Active region (AR) corona is again hotter than the quiet Sun (QS) corona by a factor of 4-10. The most widely accepted mechanism that could heat the active region corona is the energy release by current dissipation via reconnection of braided magnetic field structure, first proposed by E. N. Parker three decades ago. The first observational evidence for this mechanism has only recently been presented by Cirtain et al. by using High-resolution Coronal Imager (Hi-C) observations of an AR corona at a spatial resolution of 0.2 arcsec, which is required to resolve the coronal loops, and was not available before the rocket flight of Hi-C in July 2012. The Hi-C project is led by NASA/MSFC. In the case of the QS, work done by convection/granulation on the inter-granular feet of the coronal field lines translates into the heat observed in the corona. In the case of the AR, as here, there could be flux emergence, cancellation/submergence, or shear flows generating large stress and tension in coronal field loops which is released as heat in the corona. We are currently investigating the changes taking place in photospheric feet of the magnetic field involved with brightenings in the Hi-C AR corona. For this purpose, we are also using SDO/AIA data of +/- 2 hours around the 5 minutes Hi-C flight. In the present talk, I will first summarize some of the results of the Hi-C observations and then present some results from our recent analysis on what photospheric processes feed the magnetic energy that dissipates into heat in coronal loops.

  5. Impacts of mountains on black carbon aerosol under different synoptic meteorology conditions in the Guanzhong region, China

    NASA Astrophysics Data System (ADS)

    Zhao, Shuyu; Tie, Xuexi; Cao, Junji; Zhang, Qiang

    2015-10-01

    The Xi'an City and the surrounding area (the Guan-Zhong-GZ region) in western China have been suffering severe air pollutions during wintertime in recent years. In-situ black carbon (BC) measurement combined with a regional dynamical and chemical model (WRF-Chem model) is used to investigate the formation of a haze episode occurred from Jan. 3rd to Jan. 13th 2013. The results show that the measured BC concentrations exhibit a large day-to-day variability. The impacts of synoptic weather systems, local meteorological parameters and mountain effect on the BC variability are studied. Because the GZ region is surrounded by two major mountains, the Loess Plateau in the north and the Qinling Mountains in the south, especially the peak of the Qinling Mountains higher than 3000 m, we particularly analyze the effects of the Qinling Mountains on the BC pollution. The analysis shows that the BC pollution in Xi'an City and the GZ region is strongly affected by the synoptic weather systems, local meteorological winds and the Qinling Mountains. Under a typical northeast wind condition, winds are blocked by the Qinling Mountains, and BC particles are trapped at the foothill of the mountains, resulting in high BC concentrations in the city of Xi'an. Under a typical east wind condition, BC particles are transported along a river valley and the foothill of the Qinling Mountains. In this case, the mountain-river valley plays a role to accelerate the east wind, resulting in a reduction of the BC pollution. Under a typical calm wind condition, the BC particles are less diffused from their source region, and there is a mountain breeze from the Qinling Mountains to the city of Xi'an, and BC particles accumulate in the city, especially in the north side of the city. This study illustrates that while locating between complicated terrain conditions, such as the GZ region, the mountains play very important roles for the formation of hazes in the region.

  6. Comparison of 3 coupled models in the North Sea region under todays and future climate conditions

    NASA Astrophysics Data System (ADS)

    Klein, Birgit; Bülow, Katharina; Dieterich, Christian; Heinrich, Hartmut; Hüttl-Kabus, Sabine; Mayer, Bernhard; Meier, Markus; Mikolajewicz, Uwe; Narayan, Nikesh; Pohlmann, Thomas; Rosenhagen, Gudrun; Sein, Dmitry; Su, Jian

    2014-05-01

    Most of the common global climate models (coupled ocean/atmosphere ocean models) have too large spatial scales to be suitable in the North Sea area. Therefore either high-resolution global models have to be run or dynamical downscaling of the model-output has to be employed using regional models. Regionalized climate change simulations for the North and Baltic Sea are carried out with coupled ocean atmosphere models in the framework of the research program KLIWAS. The numerical simulations are performed by the Max-Planck Institute for Meteorology (MPI), the Swedish Meteorological and Hydrological Institute (SMHI) and the Institute of Oceanography (IfM Hamburg). Output from the models is analyzed jointly with the Federal Maritime service (BSH) and the German weather service (DWD/SWA). Temperature and sea level evolution in all three models is much more similar than the predicted salinity changes. The spatial patterns of the salinity fields in the North Sea are the result of a complex balance of fresh water input from the rivers, discharge of low salinity waters from the Baltic, inflow of high salinity waters from the Atlantic and input from the atmosphere. The hindcast simulations for this parameter are similar at the basin scale in all three models but are showing different patterns at smaller scales. All models are predicting a salinity decrease towards the end of the 21 century (2070-2099) to (1970-1999), independent of these differences, but it is much more pronounced in the runs of MPIOM/REMO and NEMO/RCA compared to HAMSOM/REMO. All models agree on the fact of a major freshening of the Baltic Outflow, while the magnitude of the freshening and the affected area in the North Sea are represented differently. The models are showing a temperature increase in the order of 2 °C at the end of the 21 century. The areas affected by Atlantic inflow are showing smaller temperature increases due to the lesser warming in the Atlantic. The annual cycle is slightly perturbed

  7. Influence of feedbacks from simulated crop growth on integrated regional hydrologic simulations under climate scenarios

    NASA Astrophysics Data System (ADS)

    van Walsum, P. E. V.

    2011-11-01

    Climate change impact modelling of hydrologic responses is hampered by climate-dependent model parameterizations. Reducing this dependency was one of the goals of extending the regional hydrologic modelling system SIMGRO with a two-way coupling to the crop growth simulation model WOFOST. The coupling includes feedbacks to the hydrologic model in terms of the root zone depth, soil cover, leaf area index, interception storage capacity, crop height and crop factor. For investigating whether such feedbacks lead to significantly different simulation results, two versions of the model coupling were set up for a test region: one with exogenous vegetation parameters, the "static" model, and one with endogenous simulation of the crop growth, the "dynamic" model WOFOST. The used parameterization methods of the static/dynamic vegetation models ensure that for the current climate the simulated long-term average of the actual evapotranspiration is the same for both models. Simulations were made for two climate scenarios. Owing to the higher temperatures in combination with a higher CO2-concentration of the atmosphere, a forward time shift of the crop development is simulated in the dynamic model; the used arable land crop, potatoes, also shows a shortening of the growing season. For this crop, a significant reduction of the potential transpiration is simulated compared to the static model, in the example by 15% in a warm, dry year. In consequence, the simulated crop water stress (the unit minus the relative transpiration) is lower when the dynamic model is used; also the simulated increase of crop water stress due to climate change is lower; in the example, the simulated increase is 15 percentage points less (of 55) than when a static model is used. The static/dynamic models also simulate different absolute values of the transpiration. The difference is most pronounced for potatoes at locations with ample moisture supply; this supply can either come from storage release of a

  8. OBSERVATION OF A NON-RADIAL PENUMBRA IN A FLUX EMERGING REGION UNDER CHROMOSPHERIC CANOPY FIELDS

    SciTech Connect

    Lim, Eun-Kyung; Yurchyshyn, Vasyl; Goode, Philip; Cho, Kyung-Suk

    2013-05-20

    The presence of a penumbra is one of the main properties of a mature sunspot, but its formation mechanism has been elusive due to a lack of observations that fully cover the formation process. Utilizing the New Solar Telescope at the Big Bear Solar Observatory, we observed the formation of a partial penumbra for about 7 hr simultaneously at the photospheric (TiO; 7057 A) and the chromospheric (H{alpha} - 1 A) spectral lines with high spatial and temporal resolution. From this uninterrupted, long observing sequence, we found that the formation of the observed penumbra was closely associated with flux emergence under the pre-existing chromospheric canopy fields. Based on this finding, we suggest a possible scenario for penumbra formation in which a penumbra forms when the emerging flux is constrained from continuing to emerge, but rather is trapped at the photospheric level by the overlying chromospheric canopy fields.

  9. Pulling the rug out from under California: Seismic images of the Mendocino Triple Junction Region

    NASA Astrophysics Data System (ADS)

    Mendocino Working Group; Trehu, Anne M.

    The active tectonic regime of northwestern California changes abruptly from transform motion to subduction at the Mendocino Triple Junction. Northward migration of the triple junction has been a major factor in the tectonic history of the continental margin of California since the Oligocene and continues at present. Understanding the effects of triple junction migration on the structure of the crust and upper mantle in this region is therefore necessary for reconstructing the geologic evolution of the continental margin of California and accurately assessing seismic hazards associated with the San Andreas fault system and the Cascadia subduction zone. In 1993 and 1994 a network of large-aperture seismic profiles was collected to image the crustal and upper-mantle structure beneath northern California and the adjacent continental margin. The data include approximately 650 km of onshore seismic refraction/reflection data, 2000 km of off-shore multichannel seismic (MCS) reflection data, and simultaneous onshore and offshore recording of the MCS airgun source to yield large-aperture data. Scientists from more than 12 institutions were involved in data acquisition.

  10. Regional allocation of biomass to U.S. energy demands under a portfolio of policy scenarios.

    PubMed

    Mullins, Kimberley A; Venkatesh, Aranya; Nagengast, Amy L; Kocoloski, Matt

    2014-01-01

    The potential for widespread use of domestically available energy resources, in conjunction with climate change concerns, suggest that biomass may be an essential component of U.S. energy systems in the near future. Cellulosic biomass in particular is anticipated to be used in increasing quantities because of policy efforts, such as federal renewable fuel standards and state renewable portfolio standards. Unfortunately, these independently designed biomass policies do not account for the fact that cellulosic biomass can equally be used for different, competing energy demands. An integrated assessment of multiple feedstocks, energy demands, and system costs is critical for making optimal decisions about a unified biomass energy strategy. This study develops a spatially explicit, best-use framework to optimally allocate cellulosic biomass feedstocks to energy demands in transportation, electricity, and residential heating sectors, while minimizing total system costs and tracking greenhouse gas emissions. Comparing biomass usage across three climate policy scenarios suggests that biomass used for space heating is a low cost emissions reduction option, while biomass for liquid fuel or for electricity becomes attractive only as emissions reduction targets or carbon prices increase. Regardless of the policy approach, study results make a strong case for national and regional coordination in policy design and compliance pathways. PMID:24512511

  11. IASI-derived Surface Temperature Under Dusty Conditions: Application to the West Africa Region.

    NASA Astrophysics Data System (ADS)

    Mechri, Rihab; Capelle, Virginie; Chedin, Alain

    2016-04-01

    Giving access to energy and water budgets, Surface Temperature (ST) is considered as a key variable for a wide range of applications in particular for meteorology and climatology. An accurate knowledge of this variable should significantly improve the monitoring of numerous atmospheric and surface processes as well as their interactions. Even-though satellite sensors bring ST global fields at different spatial and temporal scales, the accuracy of these products is still questionable especially over land or for complex atmospheric conditions (presence of clouds, of aerosols, etc.). At LMD, the ST is determined through the simultaneous "Look-up-Table" inversion of satellite METOP/IASI radiances in terms of Aerosol Optical Depth (AOD), dust layer mean altitude and surface temperature . The main aim of this work is to validate IASI ST product and to analyze its spatial and temporal variability, in particular in the presence of dust aerosols. This approach has been first applied to the West Africa region. The accuracy of this ST product will be assessed in terms of bias and standard deviation against ST products from ECMWF forecast, from other satellite products (MODIS AQUA/TERRA, AATSR,…) and from in-situ measurements for different periods ranging from July 2007 to today according to the availability of these validation data.

  12. Winter Photochemistry Underlying High Ozone in an Oil and Gas Producing Region

    NASA Astrophysics Data System (ADS)

    Brown, S. S.; Edwards, P. M.; Roberts, J. M.; Ahmadov, R.; Banta, R. M.; De Gouw, J. A.; Dube, W. P.; Field, R. A.; Gilman, J.; Graus, M.; Helmig, D.; Koss, A.; Langford, A. O.; Lefer, B. L.; Lerner, B. M.; McKeen, S. A.; Li, S. M.; Murphy, S. M.; Parrish, D. D.; Senff, C. J.; Stutz, J.; Thompson, C. R.; Trainer, M.; Veres, P. R.; Warneke, C.; Wild, R. J.; Young, C.; Yuan, B.; Zamora, R. J.; Washenfelder, R. A.

    2014-12-01

    Ozone formation during wintertime in oil and gas producing basins of the Rocky Mountain West now accounts for some of the highest ozone pollutant concentrations observed in the U.S. These events are scientifically challenging, occurring only during cold, snow covered periods when meteorological inversions concentrate pollutants near the surface, but when incident solar actinic flux that initiates photochemical reactions is at or near its minimum. A near-explicit chemical model that incorporates detailed measurements obtained during three successive winter field studies in the Uintah Basin, Utah, accurately reproduces the observed buildup of ozone and other photochemically generated species. It also identifies the sources of free radicals that drive this unusual photochemistry, and quantifies their relative contributions. Although sharing the same basic atmospheric chemistry, winter ozone formation differs from its summertime, urban counterpart in its dependence upon the relative concentrations of volatile organic compounds (VOCs) and nitrogen oxide (NOx) precursors. Observed NO­­x mixing ratios in the Uintah basin are lower than is typical of urban areas, while VOC levels are significantly larger. These extreme VOC concentrations allow for nearly optimal efficiency of ozone production from the available NO­x. This analysis will inform the design of mitigation strategies and provide insight into the response of winter ozone to primary air pollutants in other regions, particularly those where oil and gas development is contemplated.

  13. Regional aspect of highly water-stressed population estimated by world water resources under SRES scenarios

    NASA Astrophysics Data System (ADS)

    Kiguchi, M.; Shen, Y.; Kanae, S.; Oki, T.

    2008-12-01

    Global and regional populations lived in highly water-stressed basin for a function of the temperature were estimated using the socio-economical data and the outputs of GCMs. In global, the highly water-stressed population in scenario A2 rapidly increased when the anomaly of temperature is exceeding to about +1.5 deg.. In the case of the scenario A1b, the gradient of increase of highly water-stressed population was less than that in the case of the scenario A2. When the value of temperature anomaly was exceeding to about + 1.5 deg., the gradient of increase of highly water-stressed population became loose. On the other hand, the highly water-stressed population in the scenario B1 decreased when the temperature anomaly was exceeding to about +1.2 deg.. According to the estimation of the highly water-stressed population when the effect of climate change was ignored (that is, runoff was not changed), the highly water-stressed population was almost same. This result implied that it is strongly contributed by not the climate change but the socio- economical factors (ex; an irrigated area, increase of industrial water use, increase of population itself). Parry et al. (2001) pointed out that the influence on the water risk by the climate change is serious when the anomaly of temperature is exceeding to +2 deg.. However, our assessment disagrees with their assignment. When the highly water-stressed population assessment is estimated within the social elements (ex., the increase of irrigation demand, industrial demand, and population itself), the climate change is not so effective. Part of this study was financially supported by the Global Environment Research Fund, "S-4" and "S-5", from the Japanese Ministry of the Environment.

  14. Responses of Two Invasive Plants Under Various Microclimate Conditions in the Seoul Metropolitan Region

    NASA Astrophysics Data System (ADS)

    Song, Uhram; Mun, Saeromi; Ho, Chang-Hoi; Lee, Eun Ju

    2012-06-01

    The possible consequences of global warming on plant communities and ecosystems have wide-ranging ramifications. We examined how environmental change affects plant growth as a function of the variations in the microclimate along an urban-suburban climate gradient for two allergy-inducing, invasive plants, Humulus japonicus and Ambrosia artemisiifolia var. elatior. The environmental factors and plant growth responses were measured at two urban sites (Gangbuk and Seongbuk) and two suburban sites (Goyang and Incheon) around Seoul, South Korea. The mean temperatures and CO2 concentrations differed significantly between the urban (14.8 °C and 439 ppm CO2) and suburban (13.0 °C and 427 ppm CO2) sites. The soil moisture and nitrogen contents of the suburban sites were higher than those at the urban sites, especially for the Goyang site. The two invasive plants showed significantly higher biomasses and nitrogen contents at the two urban sites. We conducted experiments in a greenhouse to confirm the responses of the plants to increased temperatures, and we found consistently higher growth rates under conditions of higher temperatures. Because we controlled the other factors, the better performance of the two invasive plants appears to be primarily attributable to their responses to temperature. Our study demonstrates that even small temperature changes in the environment can confer significant competitive advantages to invasive species. As habitats become urbanized and warmer, these invasive plants should be able to displace native species, which will adversely affect people living in these areas.

  15. Responses of two invasive plants under various microclimate conditions in the Seoul metropolitan region.

    PubMed

    Song, Uhram; Mun, Saeromi; Ho, Chang-Hoi; Lee, Eun Ju

    2012-06-01

    The possible consequences of global warming on plant communities and ecosystems have wide-ranging ramifications. We examined how environmental change affects plant growth as a function of the variations in the microclimate along an urban-suburban climate gradient for two allergy-inducing, invasive plants, Humulus japonicus and Ambrosia artemisiifolia var. elatior. The environmental factors and plant growth responses were measured at two urban sites (Gangbuk and Seongbuk) and two suburban sites (Goyang and Incheon) around Seoul, South Korea. The mean temperatures and CO(2) concentrations differed significantly between the urban (14.8 °C and 439 ppm CO(2)) and suburban (13.0 °C and 427 ppm CO(2)) sites. The soil moisture and nitrogen contents of the suburban sites were higher than those at the urban sites, especially for the Goyang site. The two invasive plants showed significantly higher biomasses and nitrogen contents at the two urban sites. We conducted experiments in a greenhouse to confirm the responses of the plants to increased temperatures, and we found consistently higher growth rates under conditions of higher temperatures. Because we controlled the other factors, the better performance of the two invasive plants appears to be primarily attributable to their responses to temperature. Our study demonstrates that even small temperature changes in the environment can confer significant competitive advantages to invasive species. As habitats become urbanized and warmer, these invasive plants should be able to displace native species, which will adversely affect people living in these areas. PMID:22484518

  16. Dynamics of Floodwater Infiltration and Groundwater Recharge Under Ephemeral Channels in Arid Regions

    NASA Astrophysics Data System (ADS)

    Tatarsky, B.; Dahan, O.; Enzel, Y.

    2007-05-01

    Shallow alluvial aquifers underneath ephemeral streams are often the only reliable source of water that can sustain human habitation in arid environments (e.g. Arava Valley, Israel; Rio Andarax, Spain; Kuiseb River, Namibia). The main source of replenishment of these alluvial aquifers is recharge from floodwater infiltration. Accordingly, effective management of surface water and groundwater in arid regions requires a better understanding of the processes controlling floodwater infiltration and recharge of alluvial aquifers. This study focuses on understanding the dynamic process of floodwater infiltration from ephemeral channels while implementing innovative methods specifically designed to quantify the recharge fluxes. The monitoring system provides real-time continuous measurements of the hydraulic conditions in all three domains involved in the recharge process: (a) the flood, (b) water-content variations along the unsaturated profile, (c) the groundwater response to the recharge event. Water-content variations along the unsaturated profile were monitored using flexible TDR (FTDR) probes installed along slanted boreholes underneath the stream channel. Water levels and salinity of both the flood and the groundwater were measured simultaneously. Two study sites were selected for this work: the Buffels River, South Africa and the Kuiseb River, Namibia. The monitoring stations installed at those sites recorded several flood events during 2005/2006. Data collected during this period revealed the dynamic process in which floodwater percolates through the vadose zone and recharges the groundwater. Each flood initiated an infiltration event expressed by wetting of the vadose zone and a rise in the water table. The sequential wetting of the vadose zone allowed direct calculations of the wetting-front propagation velocities and percolation fluxes from land surface down to the groundwater. With the arrival of the wetting front to the water table, groundwater began to rise

  17. Landscape pattern and transition under natural and anthropogenic disturbance in an arid region of northwestern China

    NASA Astrophysics Data System (ADS)

    Zhang, Yu; Wang, Tianwei; Cai, Chongfa; Li, Chongguang; Liu, Yaojun; Bao, Yuze; Guan, Wuhong

    2016-02-01

    There is a pressing need to determine the relationships between driving variables and landscape transformations. Human activities shape landscapes and turn them into complex assemblages of highly diverse structures. Other factors, including climate and topography, also play significant roles in landscape transitions, and identifying the interactions among the variables is critical to environmental management. This study analyzed the configurations and spatial-temporal processes of landscape changes from 1998 to 2011 under different anthropogenic disturbances, identified the main variables that determine the landscape patterns and transitions, and quantified the relationships between pairs of driver sets. Landsat images of Baicheng and Tekes from 1998, 2006 and 2011 were used to classify landscapes by supervised classification. Redundancy analysis (RDA) and variation partitioning were performed to identify the main driving forces and to quantify the unique, shared, and total explained variation of the sets of variables. The results indicate that the proportions of otherwise identical landscapes in Baicheng and Tekes were very different. The area of the grassland in Tekes was much larger than that of the cropland; however, the differences between the grassland and cropland in Baicheng were not as pronounced. Much of the grassland in Tekes was located in an area that was near residents, whereas most of the grassland in Baicheng was far from residents. The slope, elevation, annual precipitation, annual temperature, and distance to the nearest resident were strong driving forces influencing the patterns and transitions of the landscapes. The results of the variation partitioning indicated complex interrelationships among all of the pairs of driver sets. All of the variable sets had significant explanatory roles, most of which had both unique and shared variations with the others. The results of this study can assist policy makers and planners in implementing sustainable

  18. Nitrate behaviors in unsaturated zone under farmlands with different fertilization log at Kumamoto region, Japan.

    NASA Astrophysics Data System (ADS)

    Okumura, Azusa; Hosono, Takahiro; Shimada, Jun

    2016-04-01

    Excessive application of fertilizer and manure in agricultural activities often caused an increase of nitrate concentration in groundwater. The study area, Kumamoto is also facing this type of problem. Previous studies using nitrogen-oxygen isotope ratios in nitrate, it was shown that accumulation of chemical fertilizer is the major factor of nitrate contamination in the Kumamoto region. However, once it loaded nitrogen component may change its form and isotopic composition during downwards transportation into the aquifer. Especially, in the study area where the groundwater is recharged through a thick unsaturated zone, and therefore, it is important to elucidate the phenomenon happened in the soil zone of this area. However, it has not been. To clarify the behavior of nitrogen and the change of nitrate concentration in the unsaturated zone, we analyzed the nitrogen-oxygen isotope ratios of the extracted soil water of the unsaturated zone soils, sampled in the farmland having different fertilization logs. In addition, we attempted to verify the origin of groundwater contamination by comparing with previous results. The plateaus-like topography of the study area is consists of the pyroclastic flow deposits. Land use is mainly farmland and this area is a major source of nitrogen load and transport route into the aquifer. Nitrate concentration in groundwater at terraces recharge area has been reported about 40 mg/L. Drilling survey carried out in the unsaturated zone soil on 4 farmlands with the different land use logs in such terraces. Drilling point KO and KTO were treated by both slurry and chemical fertilizers, on the other hand, point M1 and M2 were fertilized by only chemical fertilizers. The drilling depth was up to 14-15 m, and soil samples were kept on evacuated condition after sectioning into 10 cm interval. The soil water was extracted using a centrifuge machine. The extracted soil water was measured for the nitrogen-oxygen isotope ratios in nitrate and

  19. Correlation of the ionisation response at selected points of IC sensitive regions with SEE sensitivity parameters under pulsed laser irradiation

    SciTech Connect

    Gordienko, A V; Mavritskii, O B; Egorov, A N; Pechenkin, A A; Savchenkov, D V

    2014-12-31

    The statistics of the ionisation response amplitude measured at selected points and their surroundings within sensitive regions of integrated circuits (ICs) under focused femtosecond laser irradiation is obtained for samples chosen from large batches of two types of ICs. A correlation between these data and the results of full-chip scanning is found for each type. The criteria for express validation of IC single-event effect (SEE) hardness based on ionisation response measurements at selected points are discussed. (laser applications and other topics in quantum electronics)

  20. [Spatial variability of surface soil moisture content in depression area of karst region under moist and arid conditions].

    PubMed

    Zhang, Jiguang; Chen, Hongsong; Su, Yirong; Wu, Jinshui; Zhang, Wei

    2006-12-01

    By the methods of geostatistics, this paper studied the spatial structure and distribution pattern of surface soil (0 - 5 and 5 - 10 cm) moisture content in the depression area of karst region in northwest Guangxi under moist and arid conditions in the forepart of dry season. The results showed that in test area, surface soil moisture content had obvious spatial heterogeneity and anisotropy, presenting a significantly different plaque distribution pattern. Under moist condition, surface soil moisture content had a medium or stronger spatial relativity, with a range of about 33.15 and 15.75 m, respectively, and an obvious trend effect in 0 - 5 cm soil layer. Under arid condition, the spatial relativity was strong, and the spatial scale of resembling plaque had somewhat decrease, with the smallest range being 8.22 m. The moisture content under arid condition had a higher spatial variability, and thus, the sampling strategy should be based on the mean soil moisture content. The significant difference in the spatial variability and distribution pattern of surface soil moisture in test area was mainly due to the effects of physiognomy, soil mean moisture (precipitation), and topography. PMID:17330464

  1. Spatiotemporal analysis of temperature trends under climate change in the source region of the Yellow River, China

    NASA Astrophysics Data System (ADS)

    Wang, Yuli; Wang, Xuan; Li, Chunhui; Wu, Feifei; Yang, Zhifeng

    2015-01-01

    Under global climate change, the change in temperature has greatly affected the hydrological processes and water resource security in the source region of the Yellow River, which is located in the Qinghai-Tibet Plateau and serves as a major source of domestic and agricultural water supply in the watershed. Multiple spatiotemporal analysis methods, including the S-mode empirical orthogonal function analysis, the inverse distance weighted interpolation, the weighted moving average method, and the Mann-Kendall test method were used to comprehensively analyze the temperatures of 14 meteorological stations at yearly and seasonal scales from 1961 to 2010. The results indicated that (1) general trends of temperature change have been rising, with an especially significant warming trend since the late 1990s; (2) in the last five decades, temperature trends in the study area underwent three stages, namely a cool stage (approximately 1961-1980), a fluctuating stage (approximately 1981-1997), and a warm stage (approximately 1998-2010); and (3) due to the combined effects of monsoons and geographic features, the source region could be divided into three zones according to the annual temperature variations: a low-value zone centered on Henan station in the northeastern edge; a high-value zone situated in the central, southern, and western area; and a transitional zone between the two zones mentioned above. This study is helpful for understanding temperature trends under climate change and can provide a basis for ecological protection.

  2. Winter N2O emission rate and its production rate in soil underlying the snowpack in a subboreal region, Japan

    NASA Astrophysics Data System (ADS)

    Kim, Yongwon; Tanaka, Noriyuki

    2002-10-01

    Concentrations of N2O and 222Rn were observed in the snowpack and the soil from the subboreal region of Japan during the winter of 1996 to 1997. These observations were made to validate 222Rn as a proxy for temporal variation of N2O diffusivity within a snowpack having many ice lenses in order to estimate N2O emission through the snowpack to the atmosphere, to make a better evaluation of soil N2O production rate underlying the snowpack using 222Rn mixing rate in soil, and to clarify the factors influencing N2O flux and the production rate in subboreal ecosystems. Using a one-dimensional vertical diffusion model under a nonsteady state condition, N2O flux markedly increased from 0.0034 to 18 μg N/m2/d with snow depth of an average of 4.1 ± 4.4 μg N/m2/d (1σ). The wide range of low N2O flux results from the surface soil freezing in early winter and the existence of multilayered ice lenses within the snowpack throughout the winter. When the 222Rn mixing rate varied from 4.0 cm/d to 16 cm/d, the soil N2O production rate underlying the snowpack significantly increased -3.4 to 48 mg N/m3/h with an average of 22 ± 15 mg N/m3/h (1σ). The soil temperature had a remarkably positive correlation with snow depth (R = 0.85). Therefore it can be concluded that the deeper snow cover does not prevent but does promote the production of N2O in soil and its emission to the atmosphere in the subboreal region of Japan. Although we estimated some N2O flux through the snowpack during the winter, based on the results presented here and published elsewhere, the winter regional N2O emission rate through the snowpack is estimated to be 0.07 Tg N/season, which corresponds to 30% of the annual N2O emission in the boreal ecosystem in the Northern Hemisphere. This unambiguously suggests that further data on the winter N2O fluxes are needed to assess the contribution of natural soils to the regional N2O budget and to evaluate impacts of the seasonality of the N2O emission rate on

  3. Acute presentation of gestational diabetes insipidus with pre-eclampsia complicated by cerebral vasoconstriction: a case report and review of the published work.

    PubMed

    Mor, Amir; Fuchs, Yael; Zafra, Kathleen; Haberman, Shoshana; Tal, Reshef

    2015-08-01

    Gestational diabetes insipidus (GDI) is a rare, self-limited complication of pregnancy. As it is related to excess placental vasopressinase enzyme activity, which is metabolized in the liver, GDI is more common in pregnancies complicated by conditions associated with liver dysfunction. We present a case of a 41-year-old woman at 38 weeks' gestation who presented with pre-eclampsia with severe features, including impaired liver function and renal insufficiency. Following cesarean section she was diagnosed with GDI, which was further complicated by cerebral vasoconstriction as demonstrated by magnetic resonance angiography. This case raises the possibility that cerebral vasoconstriction may be related to the cause of GDI. A high index of suspicion of GDI should be maintained in patients who present with typical signs and symptoms, especially in the setting of pregnancy complications associated with liver dysfunction. PMID:25832854

  4. Pulmonary Instillation of Multi-Walled Carbon Nanotubes Promotes Coronary Vasoconstriction and Exacerbates Injury in Isolated Hearts

    PubMed Central

    Thompson, Leslie C.; Frasier, Chad R.; Sloan, Ruben C.; Mann, Erin E.; Harrison, Benjamin S.; Brown, Jared M.; Brown, David A.; Wingard, Christopher J.

    2014-01-01

    The growing use of multi-walled carbon nanotubes (MWCNTs) across industry has increased human exposures. We tested the hypothesis that pulmonary instillation of MWCNT would exacerbate cardiac ischemia/reperfusion (I/R) injury. One day following intratracheal instillation of 1, 10, or 100 μg MWCNT in Sprague-Dawley rats, we used a Langendorff isolated heart model to examine cardiac I/R injury. In the 100 μg MWCNT group we report increased premature ventricular contractions at baseline and increased myocardial infarction. This was associated with increased endothelin-1 (ET-1) release and depression of coronary flow during early reperfusion. We also tested if isolated coronary vascular responses were affected by MWCNT instillation and found trends for enhanced coronary tone, which were dependent on ET-1, cyclooxygenase, thromboxane, and Rho-kinase. We conclude that instillation of MWCNT promoted cardiac injury by depressing coronary flow, invoking vasoconstrictive mechanisms involving ET-1, cyclooxygenase, thromboxane, and Rho-kinase. PMID:23102262

  5. The mechanism of increased renal susceptibility to toxic substances in the elderly. Part I. The role of increased vasoconstriction.

    PubMed

    Jerkić, M; Vojvodić, S; López-Novoa, J M

    2001-01-01

    The mechanisms of increased susceptibility to nephrotoxins in aging are complex and incompletely understood. It is very important to try to increase our knowledge of them because adults become increasingly vulnerable to nephrotoxic substances, as they grow older. In addition, the percentage of elderly people will increase markedly in the near future, at least in the developed countries. Drugs such as diuretics, laxatives, NSAIDs, aminoglycosides and other nephrotoxic antibiotics, and converting enzyme inhibitors are used a lot by aging people and can produce severe renal problems. Beside drugs, the clinical use of radiocontrast agents also rises in older patients. It seems that the main mechanism of the increased renal susceptibility to toxic substances in the elderly is a disbalance between vasoconstrictor and vasodilator factors (in favor of vasoconstrictor ones). Increased propensity to vasoconstriction (to Ang II, ET and PAF), as well as increased levels of oxidatively modified biomolecules in the elderly, may enhance susceptibility of old kidney to toxic substances. In addition, all mechanisms that influence both mesangial and fibroblast cell proliferation and over-production of extracellular matrix might also be involved in the processes that make the old kidney prone to drug-induced chronic toxic injury. PMID:11989542

  6. Chronic hypoxia upregulates pulmonary arterial ASIC1: a novel mechanism of enhanced store-operated Ca2+ entry and receptor-dependent vasoconstriction.

    PubMed

    Jernigan, Nikki L; Herbert, Lindsay M; Walker, Benjimen R; Resta, Thomas C

    2012-03-15

    Acid-sensing ion channel 1 (ASIC1) is a newly characterized contributor to store-operated Ca(2+) entry (SOCE) in pulmonary vascular smooth muscle (VSM). Since SOCE is implicated in elevated basal VSM intracellular Ca(2+) concentration ([Ca(2+)](i)) and augmented vasoconstriction in chronic hypoxia (CH)-induced pulmonary hypertension, we hypothesized that ASIC1 contributes to these responses. To test this hypothesis, we examined effects of the specific pharmacologic ASIC1a inhibitor, psalmotoxin 1 (PcTX1), on vasoconstrictor and vessel wall [Ca(2+)](i) responses to UTP and KCl (depolarizing stimulus) in fura-2-loaded, pressurized small pulmonary arteries from control and CH (4 wk at 0.5 atm) Wistar rats. PcTX1 had no effect on basal vessel wall [Ca(2+)](i), but attenuated vasoconstriction and increases in vessel wall [Ca(2+)](i) to UTP in arteries from control and CH rats; normalizing responses between groups. In contrast, responses to the depolarizing stimulus, KCl, were unaffected by CH exposure or PcTX1. Upon examining potential Ca(2+) influx mechanisms, we found that PcTX1 prevented augmented SOCE following CH. Exposure to CH resulted in a significant increase in pulmonary arterial ASIC1 protein. This study supports a novel role of ASIC1 in elevated receptor-stimulated vasoconstriction following CH which is likely mediated through increased ASIC1 expression and SOCE. PMID:22205392

  7. [Effects of the PAF antagonist WEB 2086 on hypoxia and angiotensin II-induced pulmonary vasoconstriction in the isolated perfused rat lung].

    PubMed

    Kempfert, C; Brandt, R; Siewert, B; Kanowski, U; Oddoy, A

    1991-10-01

    Using isolated blood-perfused lung preparations of rats, we tested the influence of the PAF antagonist WEB 2086 on vasoconstriction triggered by hypoxia or angiotensin II (A II). If a constant flow was pre-set, changes in the prepulmonarily measured pressure were directly related to the changes of resistance in the pulmonary flow. WEB 2086 reduced the hypoxically conditioned vasoconstriction (HPV) when using blood as perfusion medium, the effect being dependent on the dose (ED50 = 127.3 +/- 21.1 mg/l). HPV was lowered on the average by 82% if the full pharmacologic dose of 800 mg/l WEB 2086 was added to the perfusate. The A II response was weakened to a lesser degree (by 45%). If plasma was used as perfusate, the pressure increase in response to hypoxic stimulation or A II was less marked. However, the relative effect of the PAF antagonist was analogous (attenuation by 83% or 53%, respectively). In chronically hypoxic animals (3 weeks at 10% O2) the relative pressure drop in the lesser circulation after application of WEB 2086 (400 mg/l; HPV; blood as perfusate) was definitely more pronounced (p less than 0.001). The fact that WEB partly antagonises the pulmonary vasoconstriction triggered both by alveolar hypoxy and by angiotensin II, seems to indicate that in both constrictive stimuli PAF participates in the complex mediator mechanism or that WEB 2086 exercises a non-specific vasodilatory effect on the pulmonary flow. PMID:1758848

  8. Regional climate modeling of heat stress, frost, and water stress events in the agricultural region of Southwest Western Australia under the current climate and future climate scenarios.

    NASA Astrophysics Data System (ADS)

    Kala, Jatin; Lyons, Tom J.; Abbs, Deborah J.; Foster, Ian J.

    2010-05-01

    Heat stress, frost, and water stress events have significant impacts on grain quality and production within the agricultural region (wheat-belt) of Southwest Western Australia (SWWA) (Cramb, 2000) and understanding how the frequency and intensity of these events will change in the future is crucial for management purposes. Hence, the Regional Atmospheric Modeling System (Pielke et al, 1992) (RAMS Version 6.0) is used to simulate the past 10 years of the climate of SWWA at a 20 km grid resolution by down-scaling the 6-hourly 1.0 by 1.0 degree National Center for Environmental Prediction Final Analyses from December 1999 to Present. Daily minimum and maximum temperatures, as well as daily rainfall are validated against observations. Simulations of future climate are carried out by down-scaling the Commonwealth Scientific and Industrial Research Organization (CSIRO) Mark 3.5 General Circulation Model (Gordon et al, 2002) for 10 years (2046-2055) under the SRES A2 scenario using the Cubic Conformal Atmospheric Model (CCAM) (McGregor and Dix, 2008). The 6-hourly CCAM output is then downscaled to a 20 km resolution using RAMS. Changes in extreme events are discussed within the context of the continued viability of agriculture in SWWA. Cramb, J. (2000) Climate in relation to agriculture in south-western Australia. In: The Wheat Book (Eds W. K. Anderson and J. R. Garlinge). Bulletin 4443. Department of Agriculture, Western Australia. Gordon, H. B., Rotstayn, L. D., McGregor, J. L., Dix, M. R., Kowalczyk, E. A., O'Farrell, S. P., Waterman, L. J., Hirst, A. C., Wilson, S. G., Collier, M. A., Watterson, I. G., and Elliott, T. I. (2002). The CSIRO Mk3 Climate System Model [Electronic publication]. Aspendale: CSIRO Atmospheric Research. (CSIRO Atmospheric Research technical paper; no. 60). 130 p McGregor, J. L., and Dix, M. R., (2008) An updated description of the conformal-cubic atmospheric model. High Resolution Simulation of the Atmosphere and Ocean, Hamilton, K. and Ohfuchi

  9. Moisture Flux Convergence in Regional and Global Climate Models: Implications for Droughts in the Southwestern United States Under Climate Change

    SciTech Connect

    Gao, Yanhong; Leung, Lai-Yung R.; Salathe, E.; Dominguez, Francina; Nijssen, Bart; Lettenmaier, D. P.

    2012-05-10

    The water cycle of the southwestern United States (SW) is dominated by winter storms that maintain a positive annual net precipitation. Analysis of the control and future climate from four pairs of regional and global climate models (RCMs and GCMs) shows that the RCMs simulate a higher fraction of transient eddy moisture fluxes because the hydrodynamic instabilities associated with flow over complex terrain are better resolved. Under global warming, this enables the RCMs to capture the response of transient eddies to increased atmospheric stability that allows more moisture to converge on the windward side of the mountains by blocking. As a result, RCMs simulate enhanced transient eddy moisture convergence in the SW compared to GCMs, although both robustly simulate drying due to enhanced moisture divergence by the divergent mean flow in a warmer climate. This enhanced convergence leads to reduced susceptibility to hydrological change in the RCMs compared to GCMs.

  10. Flood risk under future climate in data sparse regions: Linking extreme value models and flood generating processes

    NASA Astrophysics Data System (ADS)

    Tramblay, Yves; Amoussou, Ernest; Dorigo, Wouter; Mahé, Gil

    2014-11-01

    For many areas in the world, there is a need for future projections of flood risk in order to improve the possible mitigation actions. However, such an exercise is often made difficult in data-sparse regions, where the limited access to hydrometric data does not allow calibrating hydrological models in a robust way under non-stationary conditions. In this study we present an approach to estimate possible changes in flood risks, which incorporates flood generating processes into statistical models for extreme values. This approach is illustrated for a West African catchment, the Mono River (12,900 km2), with discharge, precipitation and temperature data available between 1988 and 2010 and where the dominant flood generating process is soil saturation. A soil moisture accounting (SMA) model, calibrated against a merged surface soil moisture microwave satellite dataset, is used to estimate the annual maximum soil saturation level that is related to the location parameter of a generalized extreme value model of annual maximum discharge. With such a model, it is possible to estimate the changes in flood quantiles from the changes in the annual maximum soil saturation level. An ensemble of regional climate models from the ENSEMBLES-AMMA project are then considered to estimate the potential future changes in soil saturation and subsequently the changes in flood risks for the period 2028-2050. A sensitivity analysis of the non-stationary flood quantiles has shown that with the projected changes on precipitation (-2%) and temperature (+1.22°) under the scenario A1B, the projected flood quantiles would stay in the range of the observed variability during 1988-2010. The proposed approach, relying on low data requirements, could be useful to estimate the projected changes in flood risks for other data-sparse catchments where the dominant flood-generating process is soil saturation.

  11. Downscaling Precipitation and Temperature Under Climate Change Over Semi-Arid Regions of Southwestern United States of America.

    NASA Astrophysics Data System (ADS)

    Shrestha, Bijaya Prakash

    Two different space-time models are developed to estimate downscaled precipitation and temperature under the rm 2 times CO_2 scenario of climate change over semi-arid regions of southwestern USA, represented by Arizona and New-Mexico (upper Rio-Grande river basin). Local precipitation and temperature are assumed to be dependent upon two effects: the first one, a global effect, is captured by atmospheric circulation pattern (CP) types and the other, a local effect, is reflected by spatially averaged daily pressure heights of the 500 hPa pressure field (h) within the region. CP classification is performed for the 500 hPa pressure fields of observed data and that obtained from the output of the Max Plank Institute (MPI) general circulation (GCM) model T21 for the rm 1times CO_2 and rm 2 times CO_2 scenarios. The evolution of CP types for different scenarios are modeled by a Markov process. Daily precipitation and temperature conditioned on a CP type are modeled by multivariate autoregressive processes. The daily precipitation probability is linked to h through a parametric regression and daily precipitation amount is modeled by a gamma distribution. The daily temperature is modeled by a two sided normal distribution whose parameters are estimated conditioned on fitted values of h. Models are validated using split sampling. Simulations are performed to generate a series of daily rainfall and temperature (maximum and minimum) both in Arizona and New Mexico stations. Statistical properties of model outputs and statistical significance tests are carried out for current conditions and under climate change using rm 2 times CO_2 scenarios. The results show that precipitation and temperature are increasing significantly with the increase in CO _2 content. Increases in temperature are more prominent in spring and fall. However the actual amounts of increase in precipitation and temperature depend both on the season and station location.

  12. Efficient generation of region-specific forebrain neurons from human pluripotent stem cells under highly defined condition

    PubMed Central

    Yuan, Fang; Fang, Kai-Heng; Cao, Shi-Ying; Qu, Zhuang-Yin; Li, Qi; Krencik, Robert; Xu, Min; Bhattacharyya, Anita; Su, Yu-Wen; Zhu, Dong-Ya; Liu, Yan

    2015-01-01

    Human pluripotent stem cells (hPSCs) have potential to differentiate to unlimited number of neural cells, which provide powerful tools for neural regeneration. To date, most reported protocols were established with an animal feeder system. However, cells derived on this system are inappropriate for the translation to clinical applications because of the introduction of xenogenetic factors. In this study, we provided an optimized paradigm to generate region-specific forebrain neurons from hPSCs under a defined system. We assessed five conditions and found that a vitronectin-coated substrate was the most efficient method to differentiate hPSCs to neurons and astrocytes. More importantly, by applying different doses of purmorphamine, a small-molecule agonist of sonic hedgehog signaling, hPSCs were differentiated to different region-specific forebrain neuron subtypes, including glutamatergic neurons, striatal medium spiny neurons, and GABA interneurons. Our study offers a highly defined system without exogenetic factors to produce human neurons and astrocytes for translational medical studies, including cell therapy and stem cell-based drug discovery. PMID:26670131

  13. Elastic wave velocities of Fe-bearing ringwoodite under pressure and temperature conditions of the mantle transition region

    NASA Astrophysics Data System (ADS)

    Higo, Y.; Inoue, T.; Irifune, T.; Li, B.; Liebermann, R. C.

    2005-12-01

    Ringwoodite (high pressure polymorph of olivine) is considered to be the most abundant mineral at depths between 520km and 660km in the mantle transition region, and it is important to accurately determine the elastic wave velocities in order to discuss the mineralogy and composition of the mantle transition region. In this study, We have developed ultrasonic interferometry conjunction with in situ X-radiation techniques (X-ray diffraction and X-radiography) in a DIA-type cubic anvil high-pressure apparatus, in order to obtain high-quality elastic wave velocity data under the conditions of the mantle transition region and measured the elastic wave velocity of iron-bearing ringwoodite under high temperature and high pressure. The specimen was hot-pressed at 19GPa and 1473K in a 3000-ton high pressure apparatus (ORANGE-3000: GRC at ehime university). High-pressure ultrasonic experiments were performed using Kawai-type high-pressure apparatus SPEED-1500 at BL04B1. The unit cell constants of pressure marker (NaCl, Au) and sample (ringwoodite) were measured for estimation of pressure and sample length. Also, X-radiography was used in this study for direct measurement of sample length at high pressure and high temperature. The ultrasonic signals were generated and received by a LiNbO3 transducer (10° Y-cut), which can produce both longitudinal and shear waves at the same time. The waveforms were very clear and the each echoes both P-wave and S-wave were identifiable at high temperature and high pressure. P-wave and S-wave velocities increasing with increasing pressure. And P-wave and S-wave velocities decrease with increasing temperature. Especially, S-wave velocity has large temperature dependence, which velocity (at 18 GPa, 1673 K) slower than those of ambient condition. The results of our high-pressure experiment, including the elastic moduli and their pressure dependence, effect of iron on the elastic moduli, as well as their implication for the mantle transition

  14. Methicillin Resistant Staphylococcus Aureus Biofilm Formation Over A Separated Flow Region Under Steady And Pulsatile Flow Conditions

    NASA Astrophysics Data System (ADS)

    Salek, M. Mehdi; Martinuzzi, Robert

    2012-02-01

    Several researchers have observed that the formation, morphology and susceptibility of bacterial biofilms are affected by the local hydrodynamic condition and, in particular, shear stresses acting on the fluid-biofilm interface. A backwards facing step (BFS) experimental model has been widely utilized as an in vitro model to examine and characterize the effect of flow separation and recirculation zones comparable to those present within various medical devices as well as those observed in vivo. The specific geometry of BFS covers a vide range of flow features observed in physiological or environmental conditions. The hypothesis of this study is that the flow behavior and structures can effectively contribute to the transport and attachment of cells and affecting the morphology of adhered colonies as well as suspended structures (i.e. biofilm streamers). Hence, the formation of the recirculation region occurring within a backward facing step (BFS) under steady and pulsatile conditions as well as three-dimensional flow structures arising close to the side walls are investigated to correlate to biofilms behavior. This hypothesis is investigated using a backward facing step incorporated into a flow cell under steady and pulsatile flow regimes to study the growth of methicillin resistant Staphylococcus aureus (MRSA) UC18 as the study microorganism.

  15. [Nitrogen Losses Under the Action of Different Land Use Types of Small Catchment in Three Gorges Region].

    PubMed

    Chen, Cheng-long; Gao, Ming; Ni, Jiu-pai; Xie, De-ti; Deng, Hua

    2016-05-15

    As an independent water-collecting area, small catchment is the source of non-point source pollution in Three Gorges Region. Choosing 3 kinds of the most representative land-use types and using them to lay monitoring points of overland runoff within the small catchment of Wangjiagou in Fuling of Three Gorges Region, the author used the samples of surface runoff collected through the twelve natural rainfalls from May to December to analyze the feature of spatial-temporal change of Nitrogen's losses concentrations under the influence of different land use types and the hillslopes and small catchments composed by those land use types, revealing the relation between different land-use types and Nitrogen's losses of small catchments in Three Gorges Region. The result showed: the average losses concentration of TN showed the biggest difference for different land use types during the period of spring crops, and the average value of dry land was 1. 61 times and 6.73 times of the values of interplanting field of mulberry and paddy field, respectively; the change of the losses concentration of TN was most conspicuous in the 3 periods of paddy field. The main element was NO₃⁻-N, and the relation between TN and NO₃⁻-N showed a significant linear correlation. TN's and NO₃⁻-N's losses concentrations were significantly and positively correlated with the area ratio of corn and mustard, but got a significant negative correlation with the area ratio of paddy and mulberry; NH₄⁺-N's losses concentrations got a significant positive correlation with the area ratio of mustard. Among all the hillslopes composed by different land use types, TN's average losses concentration of surface runoff of the hillslope composed by interplantating field of mulberry and paddy land during the three periods was the lowest, and the values were 2.55, 11.52, 8.58 mg · L⁻¹, respectively; the hillslope of rotation plough land of corn and mustard had the maximum value, and the values were

  16. Factors affecting summer maize yield under climate change in Shandong Province in the Huanghuaihai Region of China

    NASA Astrophysics Data System (ADS)

    Chen, Guoqing; Liu, Hongjun; Zhang, Jiwang; Liu, Peng; Dong, Shuting

    2012-07-01

    Clarification of influencing factors (cultivar planted, cultivation management, climatic conditions) affecting yields of summer maize ( Zea mays L.) would provide valuable information for increasing yields further under variable climatic conditions. Here, we report actual maize yields in the Huanghuaihai region over the past 50 years (1957-2007), simulated yields of major varieties in different years (Baimaya in the 1950s, Zhengdan-2 in the 1970s, Yedan-13 in the 1990s, and Zhengdan-958 in the 2000s), and factors that influence yield. The results show that, although each variety change has played a critical role in increasing maize yields, the contribution of variety to yield increase has decreased steadily over the past 50 years (42.6%-44.3% from the 1950s to the 1970s, 34.4%-47.2% from the 1970s to the 1990s, and 21.0%-37.6% from the 1990s to the 2000s). The impact of climatic conditions on maize yield has exhibited an increasing trend (0.67%-22.5% from the 1950s to the 1970s, 2.6%-27.0% from the 1970s to the 1990s, and 9.1%-51.1% from the 1990s to the 2000s); however, interannual differences can be large, especially if there were large changes in temperature and rainfall. Among climatic factors, rainfall had a greater positive influence than light and temperature on yield increase. Cultivation measures could change the contribution rates of variety and climatic conditions. Overall, unless there is a major breakthrough in variety, improving cultivation measures will remain important for increasing future summer maize yields in the Huanghuaihai region.

  17. A formula for human average whole-body SARwb under diffuse fields exposure in the GHz region

    NASA Astrophysics Data System (ADS)

    Bamba, A.; Joseph, W.; Vermeeren, G.; Thielens, A.; Tanghe, E.; Martens, L.

    2014-12-01

    A simple formula to determine the human average whole-body SAR (SARwb) under realistic propagation conditions is proposed in the GHz region, i.e. from 1.45 GHz to 5.8 GHz. The methodology is based on simulations of ellipsoidal human body models. Only the exposure (incident power densities) and the human mass are needed to apply the formula. Diffuse scattered illumination is addressed for the first time and the possible presence of a Line-of-Sight (LOS) component is addressed as well. As validation, the formula is applied to calculate the average whole-body SARwb in 3D heterogeneous phantoms, i.e. the virtual family (34 year-old male, 26 year-old female, 11 year-old girl, and 6 year-old boy) and the results are compared with numerical ones—using the Finite-Difference Time-Domain (FDTD) method—at 3 GHz. For the LOS exposure, the average relative error varies from 28% to 12% (resp. 14-12%) for the vertical polarization (resp. horizontal polarization), depending on the heteregeneous phantom. Regarding the diffuse illumination, relative errors of -39.40%, -11.70%, 10.70%, and 10.60% are obtained for the 6 year-old boy, 11 year-old girl, 26 year-old female, and 34 year-old male, respectively. The proposed formula estimates well (especially for adults) the SARwb induced by diffuse illumination in realistic conditions. In general, the correctness of the formula improves when the human mass increases. Keeping the uncertainties of the FDTD simulations in mind, the proposed formula might be important for the dosimetry community to assess rapidly and accurately the human absorption of electromagnetic radiation caused by diffuse fields in the GHz region. Finally, we show the applicability of the proposed formula to personal dosimetry for epidemiological research.

  18. Ipsilateral shoulder pain after thoracic surgery procedures under general and regional anesthesia – a retrospective observational study

    PubMed Central

    Misiołek, Hanna; Karpe, Jacek; Marcinkowski, Adrian; Jastrzębska, Aleksandra; Szelka, Anna; Czarnożycka, Adrianna; Długaszek, Michał

    2014-01-01

    Background Ipsilateral shoulder pain (ISP) is a common complication of mixed etiology after thoracic surgery (its prevalence is estimated in the literature at between 42% and 97%). It is severe and resistant to treatment (patients complain of pain despite effective epidural analgesia at the surgical site). Aim of the study The aim of this retrospective, observational study was to evaluate the prevalence of ISP in patients operated on in our facility and to determine the risk factors for ISP development. Material and methods 68 patients after thoracotomy or videothoracoscopy (video-assisted thoracic surgery – VATS) conducted under general and regional anesthesia were enrolled in the study and divided into two groups: group I without ISP and group II with postoperative ISP. We recorded age, sex, BMI, duration of surgery, type of surgery, type of regional anesthesia, and, in patients with epidural anesthesia, level of catheter placement. Results Statistically significant differences between the groups were obtained for BMI (24.67 and 27.68, respectively; p = 0.049), type of surgery (24% for thoracotomy and 0% for VATS, p = 0.026), and level of epidural catheter placement (4.35% for catheters placed at the level of Th5 or higher and 40.47% for catheters placed below Th5; p = 0.003). Conclusions The prevalence of ISP in our medical center amounts to 24% of thoracotomy patients. The fact that the difference in ISP prevalence was significantly related to the level of epidural catheter placement is consistent with the theory that ISP is related to phrenic nerve innervation. Moreover, epidural catheter placement is a modifiable factor, which can be used to reduce the prevalence of post-thoracotomy ISP. PMID:26336393

  19. Large field-of-view and depth-specific cortical microvascular imaging underlies regional differences in ischemic brain

    NASA Astrophysics Data System (ADS)

    Qin, Jia; Shi, Lei; Dziennis, Suzan; Wang, Ruikang K.

    2014-02-01

    Ability to non-invasively monitor and quantify of blood flow, blood vessel morphology, oxygenation and tissue morphology is important for improved diagnosis, treatment and management of various neurovascular disorders, e.g., stroke. Currently, no imaging technique is available that can satisfactorily extract these parameters from in vivo microcirculatory tissue beds, with large field of view and sufficient resolution at defined depth without any harm to the tissue. In order for more effective therapeutics, we need to determine the area of brain that is damaged but not yet dead after focal ischemia. Here we develop an integrated multi-functional imaging system, in which SDW-LSCI (synchronized dual wavelength laser speckle imaging) is used as a guiding tool for OMAG (optical microangiography) to investigate the fine detail of tissue hemodynamics, such as vessel flow, profile, and flow direction. We determine the utility of the integrated system for serial monitoring afore mentioned parameters in experimental stroke, middle cerebral artery occlusion (MCAO) in mice. For 90 min MCAO, onsite and 24 hours following reperfusion, we use SDW-LSCI to determine distinct flow and oxygenation variations for differentiation of the infarction, peri-infarct, reduced flow and contralateral regions. The blood volumes are quantifiable and distinct in afore mentioned regions. We also demonstrate the behaviors of flow and flow direction in the arterials connected to MCA play important role in the time course of MCAO. These achievements may improve our understanding of vascular involvement under pathologic and physiological conditions, and ultimately facilitate clinical diagnosis, monitoring and therapeutic interventions of neurovascular diseases, such as ischemic stroke.

  20. Refinement of motion correction strategies for lower-cost CT for under-resourced regions of the world

    NASA Astrophysics Data System (ADS)

    Wells, Jered R.; Segars, W. Paul; Kigongo, Christopher J. N.; Dobbins, James T., III

    2011-03-01

    This paper describes a recently developed post-acquisition motion correction strategy for application to lower-cost computed tomography (LCCT) for under-resourced regions of the world. Increased awareness regarding global health and its challenges has encouraged the development of more affordable healthcare options for underserved people worldwide. In regions such as sub-Saharan Africa, intermediate level medical facilities may serve millions with inadequate or antiquated equipment due to financial limitations. In response, the authors have proposed a LCCT design which utilizes a standard chest x-ray examination room with a digital flat panel detector (FPD). The patient rotates on a motorized stage between the fixed cone-beam source and FPD, and images are reconstructed using a Feldkamp algorithm for cone-beam scanning. One of the most important proofs-of-concept in determining the feasibility of this system is the successful correction of undesirable motion. A 3D motion correction algorithm was developed in order to correct for potential patient motion, stage instabilities and detector misalignments which can all lead to motion artifacts in reconstructed images. Motion will be monitored by the radiographic position of fiducial markers to correct for rigid body motion in three dimensions. Based on simulation studies, projection images corrupted by motion were re-registered with average errors of 0.080 mm, 0.32 mm and 0.050 mm in the horizontal, vertical and depth dimensions, respectively. The overall absence of motion artifacts in motion-corrected reconstructions indicates that reasonable amounts of motion may be corrected using this novel technique without significant loss of image quality.

  1. Proteins Encoded in Genomic Regions Associated with Immune-Mediated Disease Physically Interact and Suggest Underlying Biology

    PubMed Central

    Rossin, Elizabeth J.; Lage, Kasper; Raychaudhuri, Soumya; Xavier, Ramnik J.; Tatar, Diana; Benita, Yair

    2011-01-01

    Genome-wide association studies (GWAS) have defined over 150 genomic regions unequivocally containing variation predisposing to immune-mediated disease. Inferring disease biology from these observations, however, hinges on our ability to discover the molecular processes being perturbed by these risk variants. It has previously been observed that different genes harboring causal mutations for the same Mendelian disease often physically interact. We sought to evaluate the degree to which this is true of genes within strongly associated loci in complex disease. Using sets of loci defined in rheumatoid arthritis (RA) and Crohn's disease (CD) GWAS, we build protein–protein interaction (PPI) networks for genes within associated loci and find abundant physical interactions between protein products of associated genes. We apply multiple permutation approaches to show that these networks are more densely connected than chance expectation. To confirm biological relevance, we show that the components of the networks tend to be expressed in similar tissues relevant to the phenotypes in question, suggesting the network indicates common underlying processes perturbed by risk loci. Furthermore, we show that the RA and CD networks have predictive power by demonstrating that proteins in these networks, not encoded in the confirmed list of disease associated loci, are significantly enriched for association to the phenotypes in question in extended GWAS analysis. Finally, we test our method in 3 non-immune traits to assess its applicability to complex traits in general. We find that genes in loci associated to height and lipid levels assemble into significantly connected networks but did not detect excess connectivity among Type 2 Diabetes (T2D) loci beyond chance. Taken together, our results constitute evidence that, for many of the complex diseases studied here, common genetic associations implicate regions encoding proteins that physically interact in a preferential manner, in

  2. The effects of benzofury (5-APB) on the dopamine transporter and 5-HT2-dependent vasoconstriction in the rat.

    PubMed

    Dawson, Patrick; Opacka-Juffry, Jolanta; Moffatt, James D; Daniju, Yusuf; Dutta, Neelakshi; Ramsey, John; Davidson, Colin

    2014-01-01

    5-APB, commonly marketed as 'benzofury' is a new psychoactive substance and erstwhile 'legal high' which has been implicated in 10 recent drug-related deaths in the UK. This drug was available on the internet and in 'head shops' and was one of the most commonly sold legal highs up until its recent UK temporary ban (UK Home Office). Despite its prominence, very little is known about its pharmacology. This study was undertaken to examine the pharmacology of 5-APB in vitro. We hypothesised that 5-APB would activate the dopamine and 5-HT systems which may underlie its putative stimulant and hallucinogenic effects. Autoradiographic studies showed that 5-APB displaced both [(125)I] RTI-121 and [(3)H] ketanserin from rat brain tissue suggesting affinity at the dopamine transporter and 5-HT2 receptor sites respectively. Voltammetric studies in rat accumbens brain slices revealed that 5-APB slowed dopamine reuptake, and at high concentrations caused reverse transport of dopamine. 5-APB also caused vasoconstriction of rat aorta, an effect antagonised by the 5-HT2A receptor antagonist ketanserin, and caused contraction of rat stomach fundus, which was reversed by the 5-HT2B receptor antagonist RS-127445. These data show that 5-APB interacts with the dopamine transporter and is an agonist at the 5-HT2A and 5-HT2B receptors in the rat. Thus 5-APB's pharmacology is consistent with it having both stimulant and hallucinogenic properties. In addition, 5-APB's activity at the 5-HT2B receptor may cause cardiotoxicity. PMID:24012617

  3. Contribution of adenosine to the depression of sympathetically evoked vasoconstriction induced by systemic hypoxia in the rat

    PubMed Central

    Coney, Andrew M; Marshall, Janice M

    2003-01-01

    Previous studies have shown that systemic hypoxia evokes vasodilatation in skeletal muscle that is mediated mainly by adenosine acting on A1 receptors, and that the vasoconstrictor effects of sympathetic nerve activity are depressed during hypoxia. The aim of the present study was to investigate the role of adenosine in this depression. In anaesthetised rats, increases in femoral vascular resistance (FVR) evoked by stimulation of the lumbar sympathetic chain with bursts of impulses at 40 or 20 Hz were greater than those evoked by continuous stimulation at 2 Hz with the same number of impulses (120) over 1 min. All of these responses were substantially reduced by infusion of adenosine or by graded systemic hypoxia (breathing 12, 10 or 8 % O2), increases in FVR evoked by continuous stimulation at 2 Hz being most vulnerable. Blockade of A1 receptors ameliorated the depression caused by adenosine infusion of the increase in FVR evoked by 2 Hz only and did not ameliorate the depression caused by 8 % O2 of increases in FVR evoked by any pattern of sympathetic stimulation. A2A receptor blockade accentuated hypoxia-induced depression of the increase in FVR evoked by burst stimulation at 40 Hz, but had no other effect. Neither A1 nor A2A receptor blockade affected the depression caused by hypoxia (8 % O2) of the FVR increase evoked by noradrenaline infusion. These results indicate that endogenously released adenosine is not responsible for the depression of sympathetically evoked muscle vasoconstriction caused by systemic hypoxia; adenosine may exert a presynaptic facilitatory influence on the vasoconstrictor responses evoked by bursts at high frequency. PMID:12702736

  4. Diabetic state, high plasma insulin and angiotensin II combine to augment endothelin-1-induced vasoconstriction via ETA receptors and ERK

    PubMed Central

    Kobayashi, T; Nogami, T; Taguchi, K; Matsumoto, T; Kamata, K

    2008-01-01

    Background and purpose: Mechanisms associated with the enhanced contractile response to endothelin-1 in hyperinsulinaemic diabetes have been examined using the rat aorta. Functions for angiotensin II, endothelin-1 receptor expression and extracellular signal-regulated kinase (ERK) have been investigated. Experimental approach: Streptozotocin-induced diabetic rats were infused with angiotensin II or, following insulin treatment, were treated with losartan, an angiotensin II receptor antagonist. Contractions of aortic strips with or without endothelium, in response to endothelin-1 and angiotensin II, were examined in vitro. Aortic ETA receptors and ERK/MEK expression were measured by western blotting. Key results: Insulin-treated diabetic rats exhibited increases in plasma insulin, angiotensin II and endothelin-1. The systolic blood pressure and endothelin-1-induced contractile responses in aortae in vitro were enhanced in insulin-treated diabetic rats and blunted by chronic losartan administration. LY294002 (phosphatidylinositol 3-kinase inhibitor) and/or PD98059 (MEK inhibitor) diminished the enhanced contractile response to endothelin-1 in aortae from insulin-treated diabetic rats. ETA and ETB receptors, ERK-1/2 and MEK-1/2 protein expression and endothelin-1-stimulated ERK phosphorylation were all increased in aortae from insulin-treated diabetic rats. Such increases were blunted by chronic losartan administration. Endothelin-1-induced contraction was significantly higher in aortae from angiotensin II-infused diabetic rats. angiotensin II-infusion increased ERK phosphorylation, but the expression of endothelin receptors and ERK/MEK proteins remained unchanged. Conclusions and implications: These results suggest that the combination of high plasma angiotensin II and insulin with a diabetic state induced enhancement of endothelin-1-induced vasoconstriction, ETA receptor expression and ERK expression/activity in the aorta. Losartan improved both the diabetes

  5. Reflex vasoconstriction in aged human skin increasingly relies on Rho kinase-dependent mechanisms during whole body cooling

    PubMed Central

    Jennings, John D.; Holowatz, Lacy A.; Kenney, W. Larry

    2009-01-01

    Primary human aging may be associated with augmented Rho kinase (ROCK)-mediated contraction of vascular smooth muscle and ROCK-mediated inhibition of nitric oxide synthase (NOS). We hypothesized that the contribution of ROCK to reflex vasoconstriction (VC) is greater in aged skin. Cutaneous VC was elicited by 1) whole body cooling [mean skin temperature (Tsk) = 30.5°C] and 2) local norepinephrine (NE) infusion (1 × 10−6 M). Four microdialysis fibers were placed in the forearm skin of eight young (Y) and eight older (O) subjects for infusion of 1) Ringer solution (control), 2) 3 mM fasudil (ROCK inhibition), 3) 20 mM NG-nitro-l-arginine methyl ester (NOS inhibition), and 4) both ROCK + NOS inhibitors. Red cell flux was measured by laser-Doppler flowmetry over each site. Cutaneous vascular conductance (CVC) was calculated as flux/mean arterial pressure and normalized to baseline CVC (%ΔCVCbaseline). VC was reduced at the control site in O during cooling (Y, −34 ± 3; and O, −18 ± 3%ΔCVCbaseline; P < 0.001) and NE infusion (Y, −53 ± 4, and O, −41 ± 9%ΔCVCbaseline; P = 0.006). Fasudil attenuated VC in both age groups during mild cooling; however, this reduction remained only in O but not in Y skin during moderate cooling (Y, −30 ± 5; and O, −7 ± 1%ΔCVCbaseline; P = 0.016) and was not altered by NOS inhibition. Fasudil blunted NE-mediated VC in both age groups (Y, −23 ± 4; and O, −7 ± 3%ΔCVCbaseline; P < 0.01). Cumulatively, these data indicate that reflex VC is more reliant on ROCK in aged skin such that approximately half of the total VC response to whole body cooling is ROCK dependent. PMID:19717729

  6. Aldosterone alters the participation of endothelial factors in noradrenaline vasoconstriction differently in resistance arteries from normotensive and hypertensive rats.

    PubMed

    Xavier, Fabiano E; Blanco-Rivero, Javier; Avendaño, María Soledad; Sastre, Esther; Yela, Rubén; Velázquez, Kyra; Salaíces, Mercedes; Balfagón, Gloria

    2011-03-11

    This study analyzed the effect of aldosterone (0.05mg/kg per day, 3 weeks) on vasoconstriction induced by noradrenaline in mesenteric resistance arteries from WKY rats and SHR. Contraction to noradrenaline was measured in mesenteric resistance arteries from untreated and aldosterone-treatedrats from both strains. Participation of nitric oxide (NO), superoxide anions, thromboxane A(2) (TxA(2)) and prostacyclin in this response was determined. 6-keto-prostaglandin (PG)F1alpha and thromboxane B(2) (TxB(2)) releases were determined by enzyme immunoassay. NO and superoxide anion release were also determined by fluorescence and chemiluminiscence, respectively. Aldosterone did not modify noradrenaline-induced contraction in either strain. In mesenteric resistance arteries from both aldosterone-treated groups, endothelium removal or preincubation with NO synthesis inhibitor L-NAME increased the noradrenaline-induced contraction, while incubation with the superoxide anion scavenger tempol decreased it. Preincubation with either the COX-1/2 or COX-2 inhibitor (indomethacin and NS-398, respectively) decreased the noradrenaline contraction in aldosterone-treated animals, while this response was not modified by COX-1 inhibitor SC-560. TxA(2) synthesis inhibitor (furegrelate), or TxA2 receptor antagonist (SQ 29 548) also decreased the noradrenaline contraction in aldosterone-treated animals. In untreated SHR, but not WKY rats, this response was increased by L-NAME, and reduced by tempol, indomethacin, NS-398 or SQ 29 548. Aldosterone treatment did not modify NO or TxB(2) release, but it did increase superoxide anion and 6-keto-PGF(1alpha) release in mesenteric resistance arteries from both strains. In conclusion, chronic aldosterone treatment reduces smooth muscle contraction to alpha-adrenergic stimuli, producing a new balance in the release of endothelium-derived prostanoids and NO. PMID:21262224

  7. Hemoglobin α / eNOS Coupling at Myoendothelial Junctions is Required for Nitric Oxide Scavenging During Vasoconstriction

    PubMed Central

    Straub, Adam C.; Butcher, Joshua T.; Billaud, Marie; Mutchler, Stephanie M.; Artamonov, Mykhaylo V.; Nguyen, Anh T.; Johnson, Tyler; Best, Angela K.; Miller, Megan P.; Palmer, Lisa A.; Columbus, Linda; Somlyo, Avril V.; Le, Thu H.; Isakson, Brant E.

    2014-01-01

    Objective Hb α and eNOS form a macromolecular complex at myoendothelial junctions; the functional role of this interaction remains undefined. To test if coupling of eNOS and Hb α regulates NO signaling, vascular reactivity and blood pressure using a mimetic peptide of Hb α to disrupt this interaction. Approach and Results In silico modeling of Hb α and eNOS identified a conserved sequence of interaction. By mutating portions of Hb α, we identified a specific sequence that binds eNOS. A mimetic peptide of the Hb α sequence (Hb α X) was generated to disrupt this complex. Utilizing in vitro binding assays with purified Hb α and eNOS and ex vivo proximity ligation assays on resistance arteries, we have demonstrated that Hb α X significantly decreased interaction between eNOS and Hb α. FITC-labeling of Hb α X revealed localization to holes in the internal elastic lamina (i.e., myoendothelial junctions). To test the functional effects of Hb α X, we measured cGMP and vascular reactivity. Our results reveal augmented cGMP production and altered vasoconstriction with Hb α X. To test the in vivo effects of these peptides on blood pressure, normotensive and hypertensive mice were injected with Hb α X which caused a significant decrease in blood pressure; injection of Hb α X into eNOS−/− mice had no effect. Conclusion These results identify a novel sequence on Hb α that is important for Hb α / eNOS complex formation and is critical for nitric oxide signaling at myoendothelial junctions. PMID:25278292

  8. Water Resources Sustainability in Northwest Mexico: Analysis of Regional Infrastructure Plans under Historical and Climate Change Scenarios

    NASA Astrophysics Data System (ADS)

    Che, D.; Robles-Morua, A.; Mayer, A. S.; Vivoni, E. R.

    2012-12-01

    The arid state of Sonora, Mexico, has embarked on a large water infrastructure project to provide additional water supply and improved sanitation to the growing capital of Hermosillo. The main component of the Sonora SI project involves an interbasin transfer from rural to urban water users that has generated conflicts over water among different social sectors. Through interactions with regional stakeholders from agricultural and water management agencies, we ascertained the need for a long-term assessment of the water resources of one of the system components, the Sonora River Basin (SRB). A semi-distributed, daily watershed model that includes current and proposed reservoir infrastructure was applied to the SRB. This simulation framework allowed us to explore alternative scenarios of water supply from the SRB to Hermosillo under historical (1980-2010) and future (2031-2040) periods that include the impact of climate change. We compared three precipitation forcing scenarios for the historical period: (1) a network of ground observations from Mexican water agencies; (2) gridded fields from the North America Land Data Assimilation System (NLDAS) at 12 km resolution; and (3) gridded fields from the Weather Research and Forecasting (WRF) model at 10 km resolution. These were compared to daily historical observations at two stream gauging stations and two reservoirs to generate confidence in the simulation tools. We then tested the impact of climate change through the use of the A2 emissions scenario and HadCM3 boundary forcing on the WRF simulations of a future period. Our analysis is focused on the combined impact of existing and proposed reservoir infrastructure at two new sites on the water supply management in the SRB under historical and future climate conditions. We also explore the impact of climate variability and change on the bimodal precipitation pattern from winter frontal storms and the summertime North American monsoon and its consequences on water

  9. Comparative study of irrigation water use and groundwater recharge under various irrigation schemes in an agricultural region, central Taiwan

    NASA Astrophysics Data System (ADS)

    Chen, Shih-Kai; Jang, Cheng-Shin; Tsai, Cheng-Bin

    2016-04-01

    The risk of rice production has increased notably due to climate change in Taiwan. To respond to growing agricultural water shortage without affecting normal food production in the future, the application of water-saving irrigation will be a substantial resolution. However, the adoption of water-saving irrigation may result in the reducing of groundwater recharge because continuous flooding in the paddy fields could be regarded as an important source for groundwater recharge. The aim of this study was to evaluate the irrigation water-saving benefit and groundwater recharge deficit when adopting the System of Rice Intensification, known as SRI methodology, in the Choushui River alluvial fan (the largest groundwater pumping and the most important rice-cropping region in central Taiwan). The three-dimensional finite element groundwater model, FEMWATER, was applied to simulate the infiltration process and groundwater recharge under SRI methodology and traditional irrigation schemes including continuous irrigation, and rotational irrigation in two rice-crop periods with hydro-climatic data of 2013. The irrigation water use was then calculated by water balance. The results showed that groundwater recharge amount of SRI methodology was slightly lower than those of traditional irrigation schemes, reduced 3.6% and 1.6% in the first crop period, and reduced 3.2% and 1.6% in the second crop period, compared with continuous irrigation and rotational irrigation, respectively. However, the SRI methodology achieved notably water-saving benefit compared to the disadvantage of reducing the groundwater recharge amount. The field irrigation requirement amount of SRI methodology was significantly lower than those of traditional irrigation schemes, saving 37% and 20% of irrigation water in the first crop period, and saving 53% and 35% in the second crop period, compared with continuous irrigation and rotational irrigation, respectively. Therefore, the amount of groundwater pumping for

  10. A Framework Predicting Water Availability in a Rapidly Growing, Semi-Arid Region under Future Climate Change

    NASA Astrophysics Data System (ADS)

    Han, B.; Benner, S. G.; Glenn, N. F.; Lindquist, E.; Dahal, K. R.; Bolte, J.; Vache, K. B.; Flores, A. N.

    2014-12-01

    Climate change can lead to dramatic variations in hydrologic regime, affecting both surface water and groundwater supply. This effect is most significant in populated semi-arid regions where water availability are highly sensitive to climate-induced outcomes. However, predicting water availability at regional scales, while resolving some of the key internal variability and structure in semi-arid regions is difficult due to the highly non-linearity relationship between rainfall and runoff. In this study, we describe the development of a modeling framework to evaluate future water availability that captures elements of the coupled response of the biophysical system to climate change and human systems. The framework is built under the Envision multi-agent simulation tool, characterizing the spatial patterns of water demand in the semi-arid Treasure Valley area of Southwest Idaho - a rapidly developing socio-ecological system where urban growth is displacing agricultural production. The semi-conceptual HBV model, a population growth and allocation model (Target), a vegetation state and transition model (SSTM), and a statistically based fire disturbance model (SpatialAllocator) are integrated to simulate hydrology, population and land use. Six alternative scenarios are composed by combining two climate change scenarios (RCP4.5 and RCP8.5) with three population growth and allocation scenarios (Status Quo, Managed Growth, and Unconstrained Growth). Five-year calibration and validation performances are assessed with Nash-Sutcliffe efficiency. Irrigation activities are simulated using local water rights. Results show that in all scenarios, annual mean stream flow decreases as the projected rainfall increases because the projected warmer climate also enhances water losses to evapotranspiration. Seasonal maximum stream flow tends to occur earlier than in current conditions due to the earlier peak of snow melting. The aridity index and water deficit generally increase in the

  11. Runoff, nitrogen (N) and phosphorus (P) losses from purple slope cropland soil under rating fertilization in Three Gorges Region.

    PubMed

    Bouraima, Abdel-Kabirou; He, Binghui; Tian, Taiqiang

    2016-03-01

    Soil erosion along with soil particles and nutrients losses is detrimental to crop production. We carried out a 5-year (2010 to 2014) study to characterize the soil erosion and nitrogen and phosphorus losses caused by rainfall under different fertilizer application levels in order to provide a theoretical evidence for the agricultural production and coordinate land management to improve ecological environment. The experiment took place under rotation cropping, winter wheat-summer maize, on a 15° slope purple soil in Chongqing (China) within the Three Gorges Region (TGR). Four treatments, control (CK) without fertilizer, combined manure with chemical fertilizer (T1), chemical fertilization (T2), and chemical fertilizer with increasing fertilization (T3), were designed on experimental runoff plots for a long-term observation aiming to study their effects on soil erosion and nutrients losses. The results showed that fertilization reduced surface runoff and nutrient losses as compared to CK. T1, T2, and T3, compared to CK, reduced runoff volume by 35.7, 29.6, and 16.8 %, respectively and sediment yield by 40.5, 20.9, and 49.6 %, respectively. Regression analysis results indicated that there were significant relationships between soil loss and runoff volume in all treatments. The combined manure with chemical fertilizer (T1) treatment highly reduced total nitrogen and total phosphorus losses by 41.2 and 33.33 %, respectively as compared with CK. Through this 5-year experiment, we can conclude that, on the sloping purple soil, the combined application of manure with fertilizer is beneficial for controlling runoff sediments losses and preventing soil erosion. PMID:26517994

  12. Vasodilator responses and endothelin-dependent vasoconstriction in metabolically healthy obesity and the metabolic syndrome.

    PubMed

    Schinzari, Francesca; Iantorno, Micaela; Campia, Umberto; Mores, Nadia; Rovella, Valentina; Tesauro, Manfredi; Di Daniele, Nicola; Cardillo, Carmine

    2015-11-01

    Patients with metabolically healthy obesity (MHO) do not present the cluster of metabolic abnormalities that define the metabolic syndrome (MetS). Whether MHO is associated with lower impairment of vasoreactivity than the MetS is unknown. For this purpose, forearm blood flow (FBF) responses were measured by strain-gauge plethysmography during the intra-arterial infusion of acetylcholine (ACh), sodium nitroprusside (SNP), and/or the selective endothelin type A (ETA) receptor blocker BQ-123 in 119 obese individuals with MHO (n = 34) or with the MetS (n = 85) and in healthy lean controls (n = 56). ACh and SNP caused a significant vasodilation in both obese and lean participants (all P < 0.001). However, the response to both agents was significantly lower in the obese than in the control group (both P < 0.001). Among the obese participants, the reactivity to ACh was higher in MHO than in MetS patients, whereas the responsiveness to SNP was equally impaired in both groups (P = 0.45). Infusion of BQ-123 significantly increased FBF in obese patients (P < 0001), but not in the lean participants; hence, FBF following ETA receptor blockade was higher in both obese groups than in controls (both P < 0.001). FBF response to BQ-123 was significantly higher in patients with the MetS than in those with MHO (P = 0.007). In conclusion, patients with MHO have abnormal vascular reactivity, although their endothelial dysfunction is less pronounced than in patients with the MetS. These findings indicate that obesity is associated with vascular damage independent of those metabolic abnormalities underlying the MetS. PMID:26374766

  13. Investigating Downscaling Methods and Evaluating Climate Models for Use in Estimating Regional Water Resources in Mountainous Regions under Changing Climatic Conditions

    NASA Technical Reports Server (NTRS)

    Frei, Allan; Nolin, Anne W.; Serreze, Mark C.; Armstrong, Richard L.; McGinnis, David L.; Robinson, David A.

    2004-01-01

    The purpose of this three-year study is to develop and evaluate techniques to estimate the range of potential hydrological impacts of climate change in mountainous areas. Three main objectives are set out in the proposal. (1) To develop and evaluate transfer functions to link tropospheric circulation to regional snowfall. (2) To evaluate a suite of General Circulation Models (GCMs) for use in estimating synoptic scale circulation and the resultant regional snowfall. And (3) to estimate the range of potential hydrological impacts of changing climate in the two case study areas: the Upper Colorado River basin, and the Catskill Mountains of southeastern New York State. Both regions provide water to large populations.

  14. Lipoxygenase and cyclo-oxygenase products in the control of regional kidney blood flow in rabbits.

    PubMed

    Oliver, Jeremy J; Eppel, Gabriela A; Rajapakse, Niwanthi W; Evans, Roger G

    2003-11-01

    1. The aim of the present study was to examine the roles of cyclo-oxygenase (COX)- and lipoxygenase (LOX)-dependent arachidonate signalling cascades in the control of regional kidney blood flow. 2. In pentobarbitone-anaesthetized rabbits treated with NG-nitro-l-arginine and glyceryl trinitrate to 'clamp' nitric oxide, we determined the effects of ibuprofen (a COX inhibitor) and esculetin (a LOX inhibitor) on resting systemic and renal haemodynamics and responses to renal arterial infusions of vasoconstrictors. 3. Ibuprofen increased mean arterial pressure (14 +/- 5%) and reduced medullary laser Doppler flux (MLDF; 26 +/- 6%) when administered with esculetin. A similar pattern of responses was observed when ibuprofen was given alone, although the reduction in MLDF was not statistically significant. Esculetin tended to increase renal blood flow (RBF; 16 +/- 7%) and MLDF (28 +/- 13%) when given alone, but not when combined with ibuprofen. 4. After vehicle, renal arterial infusions of noradrenaline, angiotensin II and endothelin-1 reduced RBF and cortical laser Doppler flux (CLDF), but not MLDF. In contrast, renal arterial [Phe2,Ile3,Orn8]-vasopressin reduced MLDF but not RBF or CLDF. Ibuprofen alone did not significantly affect these responses. Esculetin, when given alone, but not when combined with ibuprofen, enhanced noradrenaline-induced renal vasoconstriction. In contrast, esculetin did not significantly affect responses to [Phe2,Ile3,Orn8]-vasopressin, angiotensin II or endothelin-1. 5. We conclude that COX products contribute to the maintenance of arterial pressure and renal medullary perfusion under 'nitric oxide clamp' conditions, but not to renal haemodynamic responses to the vasoconstrictors we tested. Lipoxygenase products may blunt noradrenaline-induced vasoconstriction, but our observations may, instead, reflect LOX-independent effects of esculetin. PMID:14678242

  15. Identifying and Addressing Infrastructure Vulnerabilities Under Climate Change in Data-Scarce Regions: the Role of Conservation

    NASA Astrophysics Data System (ADS)

    Shortridge, J.; Guikema, S.

    2015-12-01

    Climate change is expected to have dramatic impacts on built infrastructure, particularly in the water resources sector where infrastructure tends to have long lifespans and performance is highly sensitive to climate conditions. However, adapting to water resources infrastructure to climate change is challenging due to the considerable uncertainty surrounding projections of future hydrologic conditions. This has prompted the development of a number of approaches aimed at supporting planning under "deep-uncertainty" which cannot be represented probabilistically. One such method is robust decision making (RDM), which uses simulation models to assess how systems perform over a wide range of future scenarios and identify vulnerable scenarios where system performance is unacceptable. With the Lake Tana basin in Ethiopia as a case study, we use an RDM analysis to assess the vulnerability of planned irrigation infrastructure to climate change and environmental uncertainties related to data limitations. We find that planned infrastructure is vulnerable not only to climate change, but also to poorly characterized environmental conditions today. This suggests areas for research that could provide important insights into the long-term sustainability and effectiveness of the planned projects. Additionally, we evaluate the degree to which methods such as irrigation efficiency and upstream land conservation can improve the long-term performance of the proposed infrastructure. In doing so, we demonstrate how robust decision frameworks can provide decision support in data-scarce regions where more complex modeling and analysis may be impractical.

  16. Regional networks underlying interhemispheric connectivity: an EEG and DTI study in healthy ageing and amnestic mild cognitive impairment.

    PubMed

    Teipel, Stefan J; Pogarell, Oliver; Meindl, Thomas; Dietrich, Olaf; Sydykova, Djyldyz; Hunklinger, Ulrike; Georgii, Bea; Mulert, Christoph; Reiser, Maximilian F; Möller, Hans-Jürgen; Hampel, Harald

    2009-07-01

    Interhemispheric coherence derived from electroencephalogram (EEG) recordings is a measure of functional interhemispheric connectivity. Diffusion tensor imaging (DTI) determines the integrity of subcortical fiber tracts. We studied the pattern of subcortical fiber tracts underlying interhemispheric coherence and its alteration in 16 subjects with amnestic mild cognitive impairment (MCI), an at risk syndrome for Alzheimer's disease, and 20 cognitively healthy elderly control subjects using resting state EEG and high resolution DTI at 3 T. We used a multivariate network approach based on principal component analysis to determine effects of coherence on the regional pattern of diffusivity. Temporo-parietal coherence in the alpha band was significantly correlated with diffusivity in predominantly posterior white matter tracts including posterior corpus callosum, parietal, temporal and occipital lobe white matter, thalamus, midbrain, pons, and cerebellum, both in MCI subjects and controls (P < 0.05). In MCI subjects, frontal coherence in the alpha band was significantly correlated with a predominately frontal pattern of diffusivity including fiber tracts of the anterior corpus callosum, frontal lobe white matter, thalamus, pons, and cerebellum (P < 0.05). The study provides a methodology to access specific networks of subcortical fiber tracts subserving the maintenance of interhemispheric resting state coherence in the human brain. PMID:18781594

  17. Combined X-ray and Ultrasonic Measurements Under P-T Conditions of the Mantle Transition Region

    NASA Astrophysics Data System (ADS)

    Irifune, T.; Higo, Y.; Inoue, T.; Funakoshi, K.; Li, B.

    2005-12-01

    We have developed techniques to perform simultaneous in situ X-ray and ultrasonic measurements of polycrystalline high-pressure phases at pressures to 19 GPa and temperatures to 1400C, using a combination of synchrotron radiation and a large-volume multianvil apparatus at SPring-8. High-resolution CCD image of the sample yielded precise determination of the sample length under high pressure and temperature, while the ultrasonic travel time was simultaneously measured by a pulse echo overlapping using the transfer function method developed by Li et al. (2004). The pressure and temperature were independently evaluated by means of the unit-cell volume measurements of the pressure marker and of the thermocouple e.m.f., respectively. The first attempt on (Mg0.9Fe0.1)2SiO4 ringwoodite in this method was highly successful, and we have also been conducting precise P-V-T-Vp-Vs measurements on a polycrystalline majorite sample with the O`pyrolite minus olivineO_L composition. By combining the elastic velocity data on these two major high-pressure phases, we can tightly constrain the chemical composition and constitution of the mantle transition region. We also expect substantial extension of the pressure range in these measurements toward the lower mantle regime can be made either using smaller cell assembly or using harder anvil materials, such as sintered polycrystalline bodies of cBN or diamond.

  18. Direct radiative effects of sea salt for the Mediterranean region under conditions of low to moderate wind speeds

    NASA Astrophysics Data System (ADS)

    Lundgren, K.; Vogel, B.; Vogel, H.; Kottmeier, Ch.

    2013-02-01

    ABSTRACT This study deals with the direct radiative effect of sea salt on the regional scale, within both the shortwave and longwave ranges. The COSMO-ART model system has been extended and applied for a large part of Europe and adjacent waters within this investigation. For the radiation calculations, we determined the sea salt optical properties based on Mie calculations, giving the optical properties for the three sea salt modes and eight spectral intervals. The simulated sea salt aerosol optical depth is found to show strong dependence on the 10 m wind speed under cloud-free conditions. This relation is best represented by a power law fit and compares well with satellite observations. For clear-sky conditions, the simulated sea salt direct radiative effects on the shortwave and longwave radiative budgets are approximately of the same order of magnitude, but with opposite signs. This causes the net radiative effect to approach zero, which leads to a low impact on the temperature for this area.

  19. 20 CFR 661.290 - Under what circumstances may States require Local Boards to take part in regional planning...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Local Boards to take part in regional planning activities? 661.290 Section 661.290 Employees' Benefits... what circumstances may States require Local Boards to take part in regional planning activities? (a) The State may require Local Boards within a designated region (as defined at 20 CFR 660.300) to:...

  20. Method and apparatus for directing ions and other charged particles generated at near atmospheric pressures into a region under vacuum

    DOEpatents

    Smith, Richard D.; Shaffer, Scott A.

    2000-01-01

    A method and apparatus for focusing dispersed charged particles. More specifically, a series of elements within a region maintained at a pressure between 10.sup.-1 millibar and 1 bar, each having successively larger apertures forming an ion funnel, wherein RF voltages are applied to the elements so that the RF voltage on any element has phase, amplitude and frequency necessary to define a confinement zone for charged particles of appropriate charge and mass in the interior of the ion funnel, wherein the confinement zone has an acceptance region and an emmitance region and where the acceptance region area is larger than the emmitance region area.

  1. Bleomycin-induced lung injury in rats selectively abolishes hypoxic pulmonary vasoconstriction: evidence against a role for platelet-activating factor.

    PubMed

    McCormack, D G; Crawley, D E; Barnes, P J; Evans, T W

    1992-03-01

    1. The role of platelet-activating factor in the attenuated hypoxic pulmonary vasoconstriction associated with lung injury was evaluated using specific platelet-activating factor antagonists and an isolated perfused lung preparation. 2. Intratracheal bleomycin was administered to rats to produce acute lung injury. Animals received intratracheal saline (control), intratracheal bleomycin or the platelet-activating factor antagonists BN 52021, WEB 2170 or WEB 2086 before and after bleomycin treatment. Forty-eight hours after intratracheal administration of bleomycin or saline the animals were killed. 3. The increases in pulmonary artery pressure during two periods of hypoxic ventilation and in response to 0.2 microgram of angiotensin II were measured. Acetylcholine-induced vasodilatation after pre-constriction with prostaglandin F2 alpha was also measured. To quantify lung injury, the wet/dry ratio of lung weight was determined. 4. Bleomycin treatment attenuated the first and second hypoxic pressor responses by 93% and 77%, respectively, but not the pressor response to angiotensin II nor the vasodilator response to acetylcholine. BN 52021 plus bleomycin augmented the first hypoxic pressor response compared with bleomycin treatment alone, but the structurally unrelated platelet-activating factor antagonists WEB 2170 and WEB 2086 had no significant effect on the bleomycin-induced attenuation of hypoxic pulmonary vasoconstriction. None of the platelet-activating factor antagonists blocked the increase in the wet/dry lung weight ratio induced by bleomycin. 5. Bleomycin-induced lung injury selectively attenuates hypoxic pulmonary vasoconstriction, an effect that does not appear to be mediated by platelet-activating factor. The mechanism remains to be elucidated, but may involve destruction of the hypoxic 'sensor' within the respiratory tract. PMID:1372199

  2. The Effects of High Level Magnesium Dialysis/Substitution Fluid on Magnesium Homeostasis under Regional Citrate Anticoagulation in Critically Ill

    PubMed Central

    Los, Ferdinand; Brodska, Helena

    2016-01-01

    Background The requirements for magnesium (Mg) supplementation increase under regional citrate anticoagulation (RCA) because citrate acts by chelation of bivalent cations within the blood circuit. The level of magnesium in commercially available fluids for continuous renal replacement therapy (CRRT) may not be sufficient to prevent hypomagnesemia. Methods Patients (n = 45) on CRRT (2,000 ml/h, blood flow (Qb) 100 ml/min) with RCA modality (4% trisodium citrate) using calcium free fluid with 0.75 mmol/l of Mg with additional magnesium substitution were observed after switch to the calcium-free fluid with magnesium concentration of 1.50 mmol/l (n = 42) and no extra magnesium replenishment. All patients had renal indications for CRRT, were treated with the same devices, filters and the same postfilter ionized calcium endpoint (<0.4 mmol/l) of prefilter citrate dosage. Under the high level Mg fluid the Qb, dosages of citrate and CRRT were consequently escalated in 9h steps to test various settings. Results Median balance of Mg was -0.91 (-1.18 to -0.53) mmol/h with Mg 0.75 mmol/l and 0.2 (0.06–0.35) mmol/h when fluid with Mg 1.50 mmol/l was used. It was close to zero (0.02 (-0.12–0.18) mmol/h) with higher blood flow and dosage of citrate, increased again to 0.15 (-0.11–0.25) mmol/h with 3,000 ml/h of high magnesium containing fluid (p<0.001). The arterial levels of Mg were mildly increased after the change for high level magnesium containing fluid (p<0.01). Conclusions Compared to ordinary dialysis fluid the mildly hypermagnesemic fluid provided even balances and adequate levels within ordinary configurations of CRRT with RCA and without a need for extra magnesium replenishment. Trial Registration ClinicalTrials.gov Identifier: NCT01361581 PMID:27391902

  3. Weather Types, temperature and relief relationship in the Iberian Peninsula: A regional adiabatic processes under directional weather types

    NASA Astrophysics Data System (ADS)

    Peña Angulo, Dhais; Trigo, Ricardo; Cortesi, Nicola; Gonzalez-Hidalgo, Jose Carlos

    2016-04-01

    We have analyzed at monthly scale the spatial distribution of Pearson correlation between monthly mean of maximum (Tmax) and minimum (Tmin) temperatures with weather types (WTs) in the Iberian Peninsula (IP), represent them in a high spatial resolution grid (10km x 10km) from MOTEDAS dataset (Gonzalez-Hidalgo et al., 2015a). The WT classification was that developed by Jenkinson and Collison, adapted to the Iberian Peninsula by Trigo and DaCamara, using Sea Level Pressure data from NCAR/NCEP Reanalysis dataset (period 1951-2010). The spatial distribution of Pearson correlations shows a clear zonal gradient in Tmax under the zonal advection produced in westerly (W) and easterly (E) flows, with negative correlation in the coastland where the air mass come from but positive correlation to the inland areas. The same is true under North-West (NW), North-East (NE), South-West (SW) and South-East (SE) WTs. These spatial gradients are coherent with the spatial distribution of the main mountain chain and offer an example of regional adiabatic phenomena that affect the entire IP (Peña-Angulo et al., 2015b). These spatial gradients have not been observed in Tmin. We suggest that Tmin values are less sensitive to changes in Sea Level Pressure and more related to local factors. These directional WT present a monthly frequency over 10 days and could be a valuable tool for downscaling processes. González-Hidalgo J.C., Peña-Angulo D., Brunetti M., Cortesi, C. (2015a): MOTEDAS: a new monthly temperature database for mainland Spain and the trend in temperature (1951-2010). International Journal of Climatology 31, 715-731. DOI: 10.1002/joc.4298 Peña-Angulo, D., Trigo, R., Cortesi, C., González-Hidalgo, J.C. (2015b): The influence of weather types on the monthly average maximum and minimum temperatures in the Iberian Peninsula. Submitted to Hydrology and Earth System Sciences.

  4. Application of a parameter-estimation technique to modeling the regional aquifer underlying the eastern Snake River plain, Idaho

    USGS Publications Warehouse

    Garabedian, Stephen P.

    1986-01-01

    A nonlinear, least-squares regression technique for the estimation of ground-water flow model parameters was applied to the regional aquifer underlying the eastern Snake River Plain, Idaho. The technique uses a computer program to simulate two-dimensional, steady-state ground-water flow. Hydrologic data for the 1980 water year were used to calculate recharge rates, boundary fluxes, and spring discharges. Ground-water use was estimated from irrigated land maps and crop consumptive-use figures. These estimates of ground-water withdrawal, recharge rates, and boundary flux, along with leakance, were used as known values in the model calibration of transmissivity. Leakance values were adjusted between regression solutions by comparing model-calculated to measured spring discharges. In other simulations, recharge and leakance also were calibrated as prior-information regression parameters, which limits the variation of these parameters using a normalized standard error of estimate. Results from a best-fit model indicate a wide areal range in transmissivity from about 0.05 to 44 feet squared per second and in leakance from about 2.2x10 -9 to 6.0 x 10 -8 feet per second per foot. Along with parameter values, model statistics also were calculated, including the coefficient of correlation between calculated and observed head (0.996), the standard error of the estimates for head (40 feet), and the parameter coefficients of variation (about 10-40 percent). Additional boundary flux was added in some areas during calibration to achieve proper fit to ground-water flow directions. Model fit improved significantly when areas that violated model assumptions were removed. It also improved slightly when y-direction (northwest-southeast) transmissivity values were larger than x-direction (northeast-southwest) transmissivity values. The model was most sensitive to changes in recharge, and in some areas, to changes in transmissivity, particularly near the spring discharge area from

  5. Fluvial basin history in the northeastern Mediterranean region underlies dispersal and speciation patterns in the genus Dugesia (Platyhelminthes, Tricladida, Dugesiidae).

    PubMed

    Solà, Eduard; Sluys, Ronald; Gritzalis, Konstantinos; Riutort, Marta

    2013-03-01

    In this study we analyzed the phylogenetic relationships of eastern Mediterranean freshwater planarians of the genus Dugesia, estimated divergence times for the various clades, and correlated their phylogeographic patterns with geological and paleoclimatic events, in order to discover which evolutionary processes have shaped the present-day distribution of these animals. Specimens were collected from freshwater courses and lakes in continental and insular Greece. Genetic divergences and phylogenetic relationships were inferred by using the mitochondrial gene subunit I of cytochrome oxidase (COI) and the nuclear ribosomal internal transcribed spacer-1 (ITS-1) from 74 newly collected individuals from Greece. Divergence time estimates were obtained under a Bayesian framework, using the COI sequences. Two alternative geological dates for the isolation of Crete from the mainland were tested as calibration points. A clear phylogeographic pattern was present for Dugesia lineages in the Eastern Mediterranean. Morphological data, combined with information on genetic divergences, revealed that eight out of the nine known species were represented in the samples, while additional new, and still undescribed species were detected. Divergence time analyses suggested that Dugesia species became isolated in Crete after the first geological isolation of the island, and that their present distribution in the Eastern Mediterranean has been shaped mainly by vicariant events but also by dispersal. During the Messinian salinity crisis these freshwater planarians apparently were not able to cross the sea barrier between Crete and the mainland, while they probably did disperse between islands in the Aegean Sea. Their dependence on freshwater to survive suggests the presence of contiguous freshwater bodies in those regions. Our results also suggest a major extinction of freshwater planarians on the Peloponnese at the end of the Pliocene, while about 2Mya ago, when the current Mediterranean

  6. Reducing regional vulnerabilities and multi-city robustness conflicts using many-objective optimization under deep uncertainty

    NASA Astrophysics Data System (ADS)

    Reed, Patrick; Trindade, Bernardo; Jonathan, Herman; Harrison, Zeff; Gregory, Characklis

    2016-04-01

    Emerging water scarcity concerns in southeastern US are associated with several deeply uncertain factors, including rapid population growth, limited coordination across adjacent municipalities and the increasing risks for sustained regional droughts. Managing these uncertainties will require that regional water utilities identify regionally coordinated, scarcity-mitigating strategies that trigger the appropriate actions needed to avoid water shortages and financial instabilities. This research focuses on the Research Triangle area of North Carolina, seeking to engage the water utilities within Raleigh, Durham, Cary and Chapel Hill in cooperative and robust regional water portfolio planning. Prior analysis of this region through the year 2025 has identified significant regional vulnerabilities to volumetric shortfalls and financial losses. Moreover, efforts to maximize the individual robustness of any of the mentioned utilities also have the potential to strongly degrade the robustness of the others. This research advances a multi-stakeholder Many-Objective Robust Decision Making (MORDM) framework to better account for deeply uncertain factors when identifying cooperative management strategies. Results show that the sampling of deeply uncertain factors in the computational search phase of MORDM can aid in the discovery of management actions that substantially improve the robustness of individual utilities as well as the overall region to water scarcity. Cooperative water transfers, financial risk mitigation tools, and coordinated regional demand management must be explored jointly to decrease robustness conflicts between the utilities. The insights from this work have general merit for regions where adjacent municipalities can benefit from cooperative regional water portfolio planning.

  7. Reducing regional vulnerabilities and multi-city robustness conflicts using many-objective optimization under deep uncertainty

    NASA Astrophysics Data System (ADS)

    Trindade, B. C.; Reed, P. M.; Herman, J. D.; Zeff, H. B.; Characklis, G. W.

    2015-12-01

    Emerging water scarcity concerns in southeastern US are associated with several deeply uncertain factors, including rapid population growth, limited coordination across adjacent municipalities and the increasing risks for sustained regional droughts. Managing these uncertainties will require that regional water utilities identify regionally coordinated, scarcity-mitigating strategies that trigger the appropriate actions needed to avoid water shortages and financial instabilities. This research focuses on the Research Triangle area of North Carolina, seeking to engage the water utilities within Raleigh, Durham, Cary and Chapel Hill in cooperative and robust regional water portfolio planning. Prior analysis of this region through the year 2025 has identified significant regional vulnerabilities to volumetric shortfalls and financial losses. Moreover, efforts to maximize the individual robustness of any of the mentioned utilities also have the potential to strongly degrade the robustness of the others. This research advances a multi-stakeholder Many-Objective Robust Decision Making (MORDM) framework to better account for deeply uncertain factors when identifying cooperative management strategies. Results show that the sampling of deeply uncertain factors in the computational search phase of MORDM can aid in the discovery of management actions that substantially improve the robustness of individual utilities as well as of the overall region to water scarcity. Cooperative water transfers, financial risk mitigation tools, and coordinated regional demand management should be explored jointly to decrease robustness conflicts between the utilities. The insights from this work have general merit for regions where adjacent municipalities can benefit from cooperative regional water portfolio planning.

  8. Wide quantum critical region of valence fluctuations: Origin of robust quantum criticality in quasicrystal Yb15Al34Au51 under pressure

    NASA Astrophysics Data System (ADS)

    Watanabe, Shinji; Miyake, Kazumasa

    2015-03-01

    The mechanism of the emergence of robust quantum criticality in the heavy- electron quasicrystal YR15Al34Au51 is analyzed theoretically. By constructing a minimal model for the quasicrystal and its crystalline approximant, which contain concentric shell structures with Yb and Al-Au clusters, we show that a set of quantum critical points of the first-order valence transition of Yb appears as spots in the ground-state phase diagram. Their critical regions overlap each other, giving rise to a wide quantum critical region. This well explains the robust criticality observed in YR15Al34Au51 under pressure, and predicts the emergence of the common criticality in the crystalline approximant under pressure. The wider critical region in the quasicrystal than that in the crystalline approximant in the T-P phase diagram and the field-induced valence-crossover "region" in the T-H phase diagram are predicted to appear.

  9. The impact of increased mean airway pressure on contrast-enhanced MRI measurement of regional cerebral blood flow (rCBF), regional cerebral blood volume (rCBV), regional mean transit time (rMTT), and regional cerebrovascular resistance (rCVR) in human volunteers.

    PubMed

    Kolbitsch, C; Lorenz, I H; Hörmann, C; Schocke, M; Kremser, C; Zschiegner, F; Felber, S; Benzer, A

    2000-11-01

    Contrast-enhanced magnetic resonance imaging (MRI) measurement of cerebral perfusion is a diagnostic procedure increasingly gaining access to clinical practice not only in spontaneously breathing patients but also in mechanically ventilated patients. Effects of increased mean airway pressure on cerebral perfusion are entirely possible. Therefore, the present study used continuous positive airway pressure (CPAP) (12 cm H2O) to study the effects of increased mean airway pressure on cerebral perfusion in volunteers. CPAP significantly reduced regional cerebral blood flow (rCBF) and regional cerebral blood volume (rCBV) but increased regional mean transit time (rMTT) and regional cerebrovascular resistance (rCVR). Active vasoconstriction (e.g., arterial) and/or passive compression of capillary and/or venous vessel areas are the most likely underlying mechanisms. The number of interhemispheric differences in rCBF, rCBV, rMTT, and rCVR found at baseline rose when mean airway pressure was increased. These results, although obtained in volunteers, should be taken into consideration for the interpretation of contrast-enhanced MRI perfusion measurements in mechanically ventilated patients with an increased positive airway pressure. PMID:11098799

  10. Trends of abiotic damage in forest ecosystems in Germany at regional scale under SRES A1B, B1

    NASA Astrophysics Data System (ADS)

    Panferov, O.; Doering, C.; Sogachev, A.; Merklein, J.; Ahrends, B.

    2009-09-01

    Current climate projections indicate that the ongoing climate change may cause an increase of frequency of weather extremes (Leckebusch et al., 2008), which can result in wide area abiotic and consequent biotic damage events (e.g. drought and following insect attacks) within forest ecosystems. The type and degree of damage depends not only on the strength of a primary driving force itself (e.g. wind speed) but also on complex interactions between combinations of effecting agents with above- and belowground forest structure characteristics. The present study investigates the projected trends of abiotic risks factors and their combinations on coniferous and deciduous forests during the 21st Century under conditions of SRES scenarios A1B and B1. The downscaling of ECHAM5-MPIOM by the regional climate model (CLM) to the spatial resolution of 0.2° x 0.2° with daily time-steps is used for the analysis of future climate extremes and their combinations. With these input data the small-scale modeling with coupled process based sub-models (Jansen et al., 2008) was carried out for Solling region, (Central Germany) calculating the water and energy balance of spruce and beech forest ecosystems on cambisols and podzols with BROOK90 (Federer et al. 2003) and wind loading on trees with 3D ABL model SCADIS (Panferov and Sogachev, 2008). The risks of drought or wind damage for a certain forest stand result from combinations of soil water characteristics, static and gust wind loads, which in turn depend on current above- and belowground tree structure and on soil texture. The actual soil water content and forest structure depends on climate-soil-vegetation interactions in previous years. Therefore, differences of microclimatological conditions in the remaining stand after changes in forest structure are taken into account. Model outputs are aggregated to 30-years periods and compared to "present” conditions of 1971-2000. The results demonstrate an increment of abiotic risks

  11. Effects of nitric oxide (NO) on platelet-activating factor (PAF)- and. alpha. -adrenergic-stimulated vasoconstriction and glycogenolysis in the perfused rat liver

    SciTech Connect

    Moy, J.A.; Bates, J.N.; Fisher, R.A. )

    1991-03-11

    Effects of NO on hemodynamic and glycogenolytic responses to platelet-activating factor (PAF) and phenylephrine were investigated in perfused livers derived from fed rats. Infusion of NO into perfused livers inhibited PAF-induced increases in hepatic glucose output and portal pressure approximately 90% and 85%, respectively, and abolished effects of PAF on hepatic oxygen consumption. NO attenuated PAF-stimulated increases in glucose output and portal pressure, the latter indicative of hepatic vasoconstriction, with a similar dose-dependence with an IC{sub 50} of approximately 8 {mu}M. In contrast to its effects on PAF-induced responses in the perfused liver, NO inhibited increases in hepatic portal pressure in response to phenylephrine approximately 75% without altering phenylephrine-stimulated glucose output and oxygen consumption. Similarly, infusion of NO into perfused livers inhibited significantly increases in hepatic portal pressure but not increases in glucose output in response to a submaximal concentration of phenylephrine. Like NO, sodium nitroprusside significantly inhibited hemodynamic but not glycogenolytic responses to phenylephrine in perfused livers. However, PAF-stimulated alterations in hepatic portal pressure, glucose output and oxygen consumption were unaffected by infusion of sodium nitroprusside into perfused livers. These results provide the first evidence for regulatory effects of NO in the perfused liver and support the contention that PAF, unlike phenylephrine, stimulates glycogenolysis by mechanisms secondary to hepatic vasoconstriction. These observations raise the intriguing possibility that NO may act in liver to regulate hemodynamic responses to vasoactive mediators.

  12. Global models of ant diversity suggest regions where new discoveries are most likely are under disproportionate deforestation threat

    PubMed Central

    Guénard, Benoit; Weiser, Michael D.; Dunn, Robert R.

    2012-01-01

    Most of the described and probably undescribed species on Earth are insects. Global models of species diversity rarely focus on insects and none attempt to address unknown, undescribed diversity. We assembled a database representing about 13,000 records for ant generic distribution from over 350 regions that cover much of the globe. Based on two models of diversity and endemicity, we identified regions where our knowledge of ant diversity is most limited, regions we have called “hotspots of discovery.” A priori, such regions might be expected to be remote and untouched. Instead, we found that the hotspots of discovery are also the regions in which biodiversity is the most threatened by habitat destruction. Our results not only highlight the immediate need for conservation of the remaining natural habitats in these regions, but also the extent to which, by focusing on well-known groups such as vertebrates, we may fail to conserve the far greater diversity of the smaller species yet to be found. PMID:22529355

  13. Global models of ant diversity suggest regions where new discoveries are most likely are under disproportionate deforestation threat.

    PubMed

    Guénard, Benoit; Weiser, Michael D; Dunn, Robert R

    2012-05-01

    Most of the described and probably undescribed species on Earth are insects. Global models of species diversity rarely focus on insects and none attempt to address unknown, undescribed diversity. We assembled a database representing about 13,000 records for ant generic distribution from over 350 regions that cover much of the globe. Based on two models of diversity and endemicity, we identified regions where our knowledge of ant diversity is most limited, regions we have called "hotspots of discovery." A priori, such regions might be expected to be remote and untouched. Instead, we found that the hotspots of discovery are also the regions in which biodiversity is the most threatened by habitat destruction. Our results not only highlight the immediate need for conservation of the remaining natural habitats in these regions, but also the extent to which, by focusing on well-known groups such as vertebrates, we may fail to conserve the far greater diversity of the smaller species yet to be found. PMID:22529355

  14. How well can change diagnose the effects of coupling of the Regional Atmosphere on ET of an Irrigated Surface Under Extreme Advection of Heat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The role of imported heat and saturation deficit versus available energy on the energy balance of a cotton field is investigated in a semi-arid region under a range of conditions, including extreme horizontal advection of heat. Using eddy covariance measurements of water vapor fluxes, a modified Pen...

  15. Distinct preference for spatial frequency content in ventral stream regions underlying the recognition of scenes, faces, bodies and other objects.

    PubMed

    Canário, Nádia; Jorge, Lília; Loureiro Silva, M F; Alberto Soares, Mário; Castelo-Branco, Miguel

    2016-07-01

    The ventral visual pathway receives both inputs from parvocellular and magnocellular pathways, and combines information from distinct high and low spatial frequency channels (HSF and LSF). Using a random effects region of interest general linear model approach (n=21), we aimed to compare the selectivity to different spatial frequency channels in eight key areas involved in visual object recognition: FFA, OFA, and STS, for face processing; FBA, and EBA as body selective regions; (dorsal and ventral) LOC for object perception; PPA for processing information of places and VWFA as a region which responds to written verbal material. We found that face and body selective regions had significantly higher response to LSF, suggesting an important contribution of holistic processing favoring LSF channels, while other object responsive regions had a higher response to HSF, suggesting a more important role for detailed component processing. Both FBA and VWFA failed to reveal a preference to SF content. These findings apply in general to the preferred category, with the notable exception of PPA, which revealed a higher response to HSF for all categories of stimuli. Our results suggest that areas along the ventral stream have distinct spatial frequency preferences that seem to reflect both the nature of visual objects being processed, their position in the visual hierarchy, task demands and the relevance of holistic versus detailed processing. PMID:27180002

  16. Understanding recharge elasticity through large-scale simulations of Europe's karst regions under varying climatic boundary conditions

    NASA Astrophysics Data System (ADS)

    Hartmann, Andreas; Gleeson, Tom; Wagener, Thorsten

    2014-05-01

    Karst develops through the dissolution of carbonate rock. Karst groundwater in Europe is a major source of fresh water contributing up to half of the total drinking water supply in some countries. Climate model projections suggest that in the next 100 years, European karst regions will experience a strong increase in temperature and a serious decrease of precipitation - especially in the Mediterranean region. To be prepared, policy-makers need quantitative and reliable estimates of potential changes to karst water resources. This study presents an attempt to quantify karst water resources over the whole Mediterranean. This is done by quantifying large-scale karst recharge with a newly developed hydrologic model that considers the strong heterogeneities of recharge processes that evolve from carbonate rock dissolution. The model is driven by long-term gridded data from the European Climate Assessment & Dataset project (ECA&D). Soil moisture and evapotranspiration measurements that are available across Europe's carbonate rock regions are used for model evaluation. To assess the climatic sensitivity of recharge, we define the recharge elasticity as ratio of normalized changes of annual recharge to precipitation between years. Using large-scale simulations of the recharge model we can explore the spatial and temporal variability of the recharge elasticity among the Mediterranean's karst regions and understand the impact climatic change.

  17. The Role of Structural Elements of the 5'-Terminal Region of p53 mRNA in Translation under Stress Conditions Assayed by the Antisense Oligonucleotide Approach

    PubMed Central

    Swiatkowska, Agata; Zydowicz, Paulina; Gorska, Agnieszka; Suchacka, Julia; Dutkiewicz, Mariola; Ciesiołka, Jerzy

    2015-01-01

    The p53 protein is one of the major factors responsible for cell cycle regulation and stress response. In the 5’-terminal region of p53 mRNA, an IRES element has been found which takes part in the translational regulation of p53 expression. Two characteristic hairpin motifs are present in this mRNA region: G56-C169, with the first AUG codon, and U180-A218, which interacts with the Hdm2 protein (human homolog of mouse double minute 2 protein). 2′-OMe modified antisense oligomers hybridizing to the 5'-terminal region of p53 mRNA were applied to assess the role of these structural elements in translation initiation under conditions of cellular stress. Structural changes in the RNA target occurring upon oligomers’ binding were monitored by the Pb2+-induced cleavage method. The impact of antisense oligomers on the synthesis of two proteins, the full-length p53 and its isoform Δ40p53, was analysed in HT-29, MCF-7 and HepG2 cells, under normal conditions and under stress, as well as in vitro conditions. The results revealed that the hairpin U180-A218 and adjacent single-stranded region A219-A228 were predominantly responsible for high efficacy of IRES-mediated translation in the presence of stress factors. These motifs play a role of cis-acting elements which are able to modulate IRES activity, likely via interactions with protein factors. PMID:26513723

  18. Regional Approach for Linking Ecosystem Services and Livelihood Strategies Under Climate Change of Pastoral Communities in the Mongolian Steppe Ecosystem

    NASA Astrophysics Data System (ADS)

    Ojima, D. S.; Galvin, K.; Togtohyn, C.

    2012-12-01

    Dramatic changes due to climate and land use dynamics in the Mongolian Plateau affecting ecosystem services and agro-pastoral systems in Mongolia. Recently, market forces and development strategies are affecting land and water resources of the pastoral communities which are being further stressed due to climatic changes. Evaluation of pastoral systems, where humans depend on livestock and grassland ecosystem services, have demonstrated the vulnerability of the social-ecological system to climate change. Current social-ecological changes in ecosystem services are affecting land productivity and carrying capacity, land-atmosphere interactions, water resources, and livelihood strategies. The general trend involves greater intensification of resource exploitation at the expense of traditional patterns of extensive range utilization. Thus we expect climate-land use-land cover relationships to be crucially modified by the social-economic forces. The analysis incorporates information about the social-economic transitions taking place in the region which affect land-use, food security, and ecosystem dynamics. The region of study extends from the Mongolian plateau in Mongolia. Our research indicate that sustainability of pastoral systems in the region needs to integrate the impact of climate change on ecosystem services with socio-economic changes shaping the livelihood strategies of pastoral systems in the region. Adaptation strategies which incorporate integrated analysis of landscape management and livelihood strategies provides a framework which links ecosystem services to critical resource assets. Analysis of the available livelihood assets provides insights to the adaptive capacity of various agents in a region or in a community. Sustainable development pathways which enable the development of these adaptive capacity elements will lead to more effective adaptive management strategies for pastoral land use and herder's living standards. Pastoralists will have the

  19. Renal vasoconstriction by vasopressin V1a receptors is modulated by nitric oxide, prostanoids, and superoxide but not the ADP ribosyl cyclase CD38

    PubMed Central

    Kopple, Tayler E.; Arendshorst, William J.

    2014-01-01

    Renal blood flow (RBF) responses to arginine vasopressin (AVP) were tested in anesthetized wild-type (WT) and CD38−/− mice that lack the major calcium-mobilizing second messenger cyclic ADP ribose. AVP (3–25 ng) injected intravenously produced dose-dependent decreases in RBF, reaching a maximum of 25 ± 2% below basal RBF in WT and 27 ± 2% in CD38−/− mice with 25 ng of AVP. Renal vascular resistance (RVR) increased 75 ± 6% and 78 ± 6% in WT and CD38−/− mice. Inhibition of nitric oxide (NO) synthase with nitro-l-arginine methyl ester (l-NAME) increased the maximum RVR response to AVP to 308 ± 76% in WT and 388 ± 81% in CD38−/− (P < 0.001 for both). Cyclooxygenase inhibition with indomethacin increased the maximum RVR response to 125 ± 15% in WT and 120 ± 14% in CD38−/− mice (P < 0.001, <0.05). Superoxide suppression with tempol inhibited the maximum RVR response to AVP by 38% in both strains (P < 0.005) but was ineffective when administered after l-NAME. The rate of RBF recovery (relaxation) after AVP was slowed by l-NAME and indomethacin (P < 0.001, <0.005) but was unchanged by tempol. All vascular responses to AVP were abolished by an AVP V1a receptor antagonist. A V2 receptor agonist or antagonist had no effect on AVP-induced renal vasoconstriction. Taken together, the results indicate that renal vasoconstriction by AVP in the mouse is strongly buffered by vasodilatory actions of NO and prostanoids. The vasoconstriction depends on V1a receptor activation without involvement of CD38 or concomitant vasodilatation by V2 receptors. The role of superoxide is to enhance the contractile response to AVP, most likely by reducing the availability of NO rather than directly stimulating intracellular contraction signaling pathways. PMID:24623148

  20. The air quality and regional climate effects of widespread solar power generation under a changing regulatory environment

    NASA Astrophysics Data System (ADS)

    Millstein, D.; Zhai, P.; Menon, S.

    2011-12-01

    Over the past decade significant reductions of NOx and SOx emissions from coal burning power plants in the U.S. have been achieved due to regulatory action and substitution of new generation towards natural gas and wind power. Low natural gas prices, ever decreasing solar generation costs, and proposed regulatory changes, such as to the Cross State Air Pollution Rule, promise further long-run coal power plant emission reductions. Reduced power plant emissions have the potential to affect ozone and particulate air quality and influence regional climate through aerosol cloud interactions and visibility effects. Here we investigate, on a national scale, the effects on future (~2030) air quality and regional climate of power plant emission regulations in contrast to and combination with policies designed to aggressively promote solar electricity generation. A sophisticated, economic and engineering based, hourly power generation dispatch model is developed to explore the integration of significant solar generation resources (>10% on an energy basis) at various regions across the county, providing detailed estimates of substitution of solar generation for fossil fuel generation resources. Future air pollutant emissions from all sectors of the economy are scaled based on the U.S. Environmental Protection Agency's National Emission Inventory to account for activity changes based on population and economic projections derived from county level U.S. Census data and the Energy Information Administration's Annual Energy Outlook. Further adjustments are made for technological and regulatory changes applicable within various sectors, for example, emission intensity adjustments to on-road diesel trucking due to exhaust treatment and improved engine design. The future year 2030 is selected for the emissions scenarios to allow for the development of significant solar generation resources. A regional climate and air quality model (Weather Research and Forecasting, WRF model) is

  1. Interannual variability of regional evapotranspiration under precipitation extremes: A case study of the Youngsan River basin in Korea

    NASA Astrophysics Data System (ADS)

    Song, Youngkeun; Ryu, Youngryel; Jeon, Soohyun

    2014-11-01

    Understanding basin-scale evapotranspiration (ET) is an important issue for the management of regional water resources, especially with the recent trend of intensified precipitation (P). This study assessed the spatial and temporal variations of regional ET in response to P extremes, for various types of land-cover across the Youngsan River basin in Korea. The spatial distribution of monthly P and ET from 2001 to 2009 were estimated using rainfall records from 40 weather stations located across the basin and a satellite-derived, process-based ET model Breathing Earth System Simulator (BESS) (Ryu et al., 2011), respectively. The study periods were focused on the recent years with abnormally large, small and normal P, which were identified from anomalies in the z-sores of long-term (1973-2011) rainfall records. The variation of regional ET was assessed in terms of: (1) the controlling factors, using the statistics of related meteorological and geographical data, (2) a water-energy balance, using Budyko's framework, and (3) the water balance of four selected watersheds in the region, using the partitioning of annual P into ET and riverflow discharge (Q). The total annual ET of this region decreased in abnormally large-P year and increased in small-P year, because the ET in July to August (which accounts for more than 36% of annual ET) was limited by the available energy rather than available water due to the summer monsoon. In terms of land cover types, forests showed larger interannual variability in ET than paddy fields or cropland, with the differences in ET between large and small-P years being 108 and 82 mm yr-1, respectively. The sensitivity of annual ET to P extremes was significantly related to the leaf area index (LAI), rather than soil properties, topography, or specific land-cover type (p < 0.05, generalized linear model). However, the interannual variations of ET were not large (15-18%) compared to those of annual P (51-62%) and Q (108-232%) during 2002

  2. Underlying synovial sarcoma in a patient with a history of complex regional pain syndrome: a case report.

    PubMed

    Bernard, Joshua; Johnston, Leslie; Brennan, Todd

    2013-01-01

    Synovial sarcoma, although commonly found in the lower extremities, is considered a rare neoplasm. One of the distinguishing features of a synovial sarcoma is its initial benign features that can later turn into a more aggressive lesion. Because of the subtle early features, synovial sarcoma can be mistaken for other pathologic entities that present with clinical signs of erythema, warmth, edema, and pain. We present a patient who was originally diagnosed with complex regional pain syndrome. That diagnosis and subsequent treatment of complex regional pain syndrome likely delayed the appropriate evaluation, which led to a 9-month lag in the proper diagnosis. After magnetic resonance imaging and biopsy were performed, synovial sarcoma was diagnosed. The patient was referred to an orthopedic oncologist, who performed a transtibial amputation and chemotherapy. Although rare, neoplasm should always be considered in the differential diagnosis of a clinical presentation of a painful erythematous and edematous mass. PMID:23158107

  3. Integration of Earth System Models and Workflow Management under iRODS for the Northeast Regional Earth System Modeling Project

    NASA Astrophysics Data System (ADS)

    Lengyel, F.; Yang, P.; Rosenzweig, B.; Vorosmarty, C. J.

    2012-12-01

    The Northeast Regional Earth System Model (NE-RESM, NSF Award #1049181) integrates weather research and forecasting models, terrestrial and aquatic ecosystem models, a water balance/transport model, and mesoscale and energy systems input-out economic models developed by interdisciplinary research team from academia and government with expertise in physics, biogeochemistry, engineering, energy, economics, and policy. NE-RESM is intended to forecast the implications of planning decisions on the region's environment, ecosystem services, energy systems and economy through the 21st century. Integration of model components and the development of cyberinfrastructure for interacting with the system is facilitated with the integrated Rule Oriented Data System (iRODS), a distributed data grid that provides archival storage with metadata facilities and a rule-based workflow engine for automating and auditing scientific workflows.

  4. GPS slant total electron content accuracy using the single layer model under different geomagnetic regions and ionospheric conditions

    NASA Astrophysics Data System (ADS)

    Brunini, C.; Azpilicueta, F.

    2010-05-01

    The use of observations from the Global Positioning System (GPS) has significantly impacted the study of the ionosphere. As it is widely known, dual-frequency GPS observations can provide very precise estimation of the slant Total Electron Content (sTEC—the linear integral of the electron density along a ray-path) and that the precision level is bounded by the carrier-phase noise and multi-path effects on both frequencies. Despite its precision, GPS sTEC estimations can be systematically affected by errors in the estimation of the satellites and receivers by Inter-Frequency Biases (IFB) that are simultaneously determined with the sTEC. Thus, the ultimate accuracy of the GPS sTEC estimation is determined by the errors with which the IFBs are estimated. This contribution attempts to assess the accuracy of IFBs estimation techniques based on the single layer model for different ionospheric regions (low, mid and high magnetic latitude); different seasons (summer and winter solstices and spring and autumn equinoxes); different solar activity levels (high and low); and different geomagnetic conditions (quiet and very disturbed). The followed strategy relies upon the generation of a synthetic data set free of IFB, multi-path, measurement noise and of any other error source. Therefore, when a data set with such properties is used as the input of the IFB estimation algorithms, any deviation from zero on the estimated IFBs should be taken as indications of the errors introduced by the estimation technique. The truthfulness of this assessment work is warranted by the fact that the synthetic data sets resemble, as realistically as possible, the different conditions that may happen in the real ionosphere. The results of this work show that during the high solar activity period the accuracy for the estimated sTEC is approximately of ±10 TECu for the low geomagnetic region and of ±2.2 TECu for the mid-latitude. During low solar activity the accuracy can be assumed to be in

  5. Microbial contamination of vegetable crop and soil profile in arid regions under controlled application of domestic wastewater

    PubMed Central

    Balkhair, Khaled S.

    2015-01-01

    Increasing lack of potable water in arid countries leads to the use of treated wastewater for crop production. However, the use of inappropriate irrigation practices could result in a serious contamination risk to plants, soils, and groundwater with sewage water. This research was initiated in view to the increasing danger of vegetable crops and groundwater contamination with pathogenic bacteria due to wastewater land application. The research was designed to study: (1) the effect of treated wastewater irrigation on the yield and microbial contamination of the radish plant under field conditions; (2) contamination of the agricultural soil profile with fecal coliform bacteria. Effluent from a domestic wastewater treatment plant (100%) in Jeddah city, Saudi Arabia, was diluted to 80% and 40% with the groundwater of the experimental site constituting three different water qualities plus groundwater as control. Radish plant was grown in two consecutive seasons under two drip irrigation systems and four irrigation water qualities. Upon harvesting, plant weight per ha, total bacterial, fecal coliform, fecal streptococci were detected per 100 g of dry matter and compared with the control. The soil profile was also sampled at an equal distance of 3 cm from soil surface for fecal coliform detection. The results indicated that the yield increased significantly under the subsurface irrigation system and the control water quality compared to surface irrigation system and other water qualities. There was a considerable drop in the count of all bacteria species under the subsurface irrigation system compared to surface irrigation. The bacterial count/g of the plant shoot system increased as the percentage of wastewater in the irrigation water increased. Most of the fecal coliform bacteria were deposited in the first few centimeters below the column inlet and the profile exponentially decreased with increasing depth. PMID:26858571

  6. Microbial contamination of vegetable crop and soil profile in arid regions under controlled application of domestic wastewater.

    PubMed

    Balkhair, Khaled S

    2016-01-01

    Increasing lack of potable water in arid countries leads to the use of treated wastewater for crop production. However, the use of inappropriate irrigation practices could result in a serious contamination risk to plants, soils, and groundwater with sewage water. This research was initiated in view to the increasing danger of vegetable crops and groundwater contamination with pathogenic bacteria due to wastewater land application. The research was designed to study: (1) the effect of treated wastewater irrigation on the yield and microbial contamination of the radish plant under field conditions; (2) contamination of the agricultural soil profile with fecal coliform bacteria. Effluent from a domestic wastewater treatment plant (100%) in Jeddah city, Saudi Arabia, was diluted to 80% and 40% with the groundwater of the experimental site constituting three different water qualities plus groundwater as control. Radish plant was grown in two consecutive seasons under two drip irrigation systems and four irrigation water qualities. Upon harvesting, plant weight per ha, total bacterial, fecal coliform, fecal streptococci were detected per 100 g of dry matter and compared with the control. The soil profile was also sampled at an equal distance of 3 cm from soil surface for fecal coliform detection. The results indicated that the yield increased significantly under the subsurface irrigation system and the control water quality compared to surface irrigation system and other water qualities. There was a considerable drop in the count of all bacteria species under the subsurface irrigation system compared to surface irrigation. The bacterial count/g of the plant shoot system increased as the percentage of wastewater in the irrigation water increased. Most of the fecal coliform bacteria were deposited in the first few centimeters below the column inlet and the profile exponentially decreased with increasing depth. PMID:26858571

  7. Will ice flow in land-terminating regions of the Greenland ice sheet accelerate under future climate warming?

    NASA Astrophysics Data System (ADS)

    Doyle, S. H.; Hubbard, A.

    2015-12-01

    Recent observations and modelling studies investigating the dynamic response of land-terminating regions of the Greenland ice sheet to a warmer climate remain at best unreconciled and at worst equivocal and contradictory. Some studies suggest that ice flow will be regulated over annual time scales by the development of efficient subglacial drainage. Others suggest that such self-regulation processes may not be effective at higher elevations and that the recent and projected expansion of supraglacial lakes further into the ice sheet interior has lead to increased ice flow at high elevations. On the other hand, the observation that rapid in situ supraglacial lake drainage events may be triggered by precursory basal motion have led to the argument that, by inference, such lake drainage in the interior may be impossible, or at least hindered, by reduced strain rates and lack of surface crevasses in these regions. The response of the Greenland ice sheet to a warmer, wetter climate, in which late summer and autumnal cyclonic weather events drive widespread melt, rainfall and transient accelerations may also need to be accounted for in assessments of future Greenland ice mass loss if predicted changes in Greenland's climate are realised. This talk will critically assess recent insights gained into this topic, attempt to resolve some of them, and suggest directions for future research.

  8. Agricultural production and groundwater depletion under climate variability in India - Results from a regional scale crop modeling approach

    NASA Astrophysics Data System (ADS)

    Siegfried, T. U.; Sobolowski, S.; Fishman, R.; Vasquez, V.; Raj, P.; Narula, K. K.; Modi, V.; Lall, U.

    2009-12-01

    In India, recent declines in national food security may point to systemic deficiencies of agricultural production. Over the past decade and in the face of declining public investments in irrigation projects, the growth of production has increasingly become reliant on the allocation of large volumes of groundwater in an unsustainable manner. As a result, shallow as well as deep fossil groundwater resources are increasingly depleted and the buffer that mitigates negative impacts on production in case of Monsoonal dry-spells / drought conditions is lost. In the face of future climate and food supply uncertainty, it is vital that the connections between climate variability, unsustainable irrigation practices and their impacts on regional scale agricultural production be quantified and better understood. In our analysis, we focus on rice production in the Telengana region in Andhra Pradesh, which is characterized by a semi-arid tropical climate that is driven by the bimodal seasonality of the south-western monsoon. Traditionally, agricultural production of rice was constrained by precipitation variations during the wet season (Kharif). However, the advent of inexpensive pump technology in the 1970's, coupled with governmentally subsidized electricity has allowed year-round rice production. Thus, the Monsoon rains must not only drive wet season production but must also sufficiently recharge groundwater in order to support dry season production. Observed Production time series are characterized by non-stationarity and heteroscedasticity. Using a subset of eight districts, a non-linear Gaussian Process regression model is developed and yearly crop production is modeled at the district level over 48 years. We show that interannual climate variations, in the form of the monsoon rains, play a significant role in determining the area of land set aside for dry season planting and thus affect total yearly production. The results suggest that a non-linear Bayesian regression

  9. Future agricultural water demand under climate change: regional variability and uncertainties arising from CMIP5 climate projections

    NASA Astrophysics Data System (ADS)

    Schewe, J.; Wada, Y.; Wisser, D.

    2012-12-01

    The agricultural sector (irrigation and livestock) uses by far the largest amount of water among all sectors and is responsible for 70% of the global water withdrawal. At a country scale, irrigation water withdrawal often exceeds 90% of the total water used in many of emerging and developing countries such as India, Pakistan, Iran and Mexico, sustaining much of food production and the livelihood of millions of people. The livestock sector generally accounts less than 1-2% of total water withdrawal, yet exceeds 10-30% of the total water used in many of the African countries. Future agricultural water demand is, however, subject to large uncertainties due to anticipated climate change, i.e. warming temperature and changing precipitation variability, in various regions of the world. Here, we use a global hydrological and water resources model to quantify the impact of climate change on regional irrigation and livestock water demand, and the resulting uncertainties arsing from newly available CMIP5 climate projections obtained through Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP; http://www.isi-mip.org/). Irrigation water requirement per unit crop area is estimated by simulating daily soil water balance with crop-related data. Livestock water demand is calculated by combining livestock densities with their drinking water requirements that is a function of air temperature. The results of the ensemble mean show that global irrigation and livestock water demand increased by ~6% and ~12% by 2050 respectively primarily due to higher evaporative demand as a result of increased temperature. At a regional scale, agricultural water demand decreased over some parts of Europe (e.g., Italy, Germany) and Southeast Asia (e.g., the Philippines, Malaysia), but increased over South Asia, the U.S., the Middle East and Africa. However, the projections are highly uncertain over many parts of the world. The results of the ensemble projections in agricultural water demand

  10. Stable Carbon Isotope Discrimination Is under Genetic Control in the C4 Species Maize with Several Genomic Regions Influencing Trait Expression1[W

    PubMed Central

    Gresset, Sebastian; Westermeier, Peter; Rademacher, Svenja; Ouzunova, Milena; Presterl, Thomas; Westhoff, Peter; Schön, Chris-Carolin

    2014-01-01

    In plants with C4 photosynthesis, physiological mechanisms underlying variation in stable carbon isotope discrimination (Δ13C) are largely unknown, and genetic components influencing Δ13C have not been described. We analyzed a maize (Zea mays) introgression library derived from two elite parents to investigate whether Δ13C is under genetic control in this C4 species. High-density genotyping with the Illumina MaizeSNP50 Bead Chip was used for a detailed structural characterization of 89 introgression lines. Phenotypic analyses were conducted in the field and in the greenhouse for kernel Δ13C as well as plant developmental and photosynthesis-related traits. Highly heritable significant genetic variation for Δ13C was detected under field and greenhouse conditions. For several introgression library lines, Δ13C values consistently differed from the recurrent parent within and across the two phenotyping platforms. Δ13C was significantly associated with 22 out of 164 analyzed genomic regions, indicating a complex genetic architecture of Δ13C. The five genomic regions with the largest effects were located on chromosomes 1, 2, 6, 7, and 9 and explained 55% of the phenotypic variation for Δ13C. Plant development stage had no effect on Δ13C expression, as phenotypic as well as genotypic correlations between Δ13C, flowering time, and plant height were not significant. To our knowledge, this is the first study demonstrating Δ13C to be under polygenic control in the C4 species maize. PMID:24280436

  11. Income level and regional policies, underlying factors associated with unwarranted variations in conservative breast cancer surgery in Spain

    PubMed Central

    2011-01-01

    Background Geographical variations in medical practice are expected to be small when the evidence about the effectiveness and safety of a particular technology is abundant. This would be the case of the prescription of conservative surgery in breast cancer patients. In these cases, when variation is larger than expected by need, socioeconomic factors have been argued as an explanation. Objectives: Using an ecologic design, our study aims at describing the variability in the use of surgical conservative versus non-conservative treatment. Additionally, it seeks to establish whether the socioeconomic status of the healthcare area influences the use of one or the other technique. Methods 81,868 mastectomies performed between 2002 and 2006 in 180 healthcare areas were studied. Standardized utilization rates of breast cancer conservative (CS) and non-conservative (NCS) procedures were estimated as well as the variation among areas, using small area statistics. Concentration curves and dominance tests were estimated to determine the impact of income and instruction levels in the healthcare area on surgery rates. Multilevel analyses were performed to determine the influence of regional policies. Results Variation in the use of CS was massive (4-fold factor between the highest and the lowest rate) and larger than in the case of NCS (2-fold), whichever the age group. Healthcare areas with higher economic and instruction levels showed highest rates of CS, regardless of the age group, while areas with lower economic and educational levels yielded higher rates of NCS interventions. Living in a particular Autonomous Community (AC), explained a substantial part of the CS residual variance (up to a 60.5% in women 50 to 70). Conclusion The place where a woman lives -income level and regional policies- explain the unexpectedly high variation found in utilization rates of conservative breast cancer surgery. PMID:21504577

  12. Crop identification for the delineation of irrigated regions under scarce data conditions: a new approach based on chaos theory

    NASA Astrophysics Data System (ADS)

    Mangiarotti, S.; Muddu, S.; Sharma, A. K.; Corgne, S.; Ruiz, L.; Hubert-Moy, L.

    2015-12-01

    Groundwater is one of the main water reservoirs used for irrigation in regions of scarce water resources. For this reason, crop irrigation is expected to have a direct influence on this reservoir. To understand the time evolution of the groundwater table and its storage changes, it is important to delineate irrigated crops, whose evaporative demand is relatively higher. Such delineation may be performed based on classical classification approaches using optical remote sensing. However, it remains a difficult problem in regions where plots do not exceed a few hectares and exhibit a very heterogeneous pattern with multiple crops. This difficulty is emphasized in South India where two or three months of cloudy conditions during the monsoon period can hide crop growth during the year. An alternative approach is introduced here that takes advantage of such scarce signal. Ten different crops are considered in the present study. A bank of crop models is first established based on the global modeling technique [1]. These models are then tested using original time series (from which models were obtained) in order to evaluate the information that can be deduced from these models in an inverse approach. The approach is then tested on an independent data set and is finally applied to a large ensemble of 10,000 time series of plot data extracted from the Berambadi catchment (AMBHAS site) part of the Kabini River basin CZO, South India. Results show that despite the important two-month gap in satellite observations in the visible band, interpolated vegetation index remains an interesting indicator for identification of crops in South India. [1] S. Mangiarotti, R. Coudret, L. Drapeau, & L. Jarlan, Polynomial search and global modeling: Two algorithms for modeling chaos, Phys. Rev. E, 86(4), 046205 (2012).

  13. Carbon sequestration and Jerusalem artichoke biomass under nitrogen applications in coastal saline zone in the northern region of Jiangsu, China.

    PubMed

    Niu, Li; Manxia, Chen; Xiumei, Gao; Xiaohua, Long; Hongbo, Shao; Zhaopu, Liu; Zed, Rengel

    2016-10-15

    Agriculture is an important source of greenhouse gases, but can also be a significant sink. Nitrogen fertilization is effective in increasing agricultural production and carbon storage. We explored the effects of different rates of nitrogen fertilization on biomass, carbon density, and carbon sequestration in fields under the cultivation of Jerusalem artichoke as well as in soil in a coastal saline zone for two years. Five nitrogen fertilization rates were tested (in guream(-2)): 4 (N1), 8 (N2), 12 (N3), 16 (N4), and 0 (control, CK). The biomass of different organs of Jerusalem artichoke during the growth cycle was significantly higher in N2 than the other treatments. Under different nitrogen treatments, carbon density in organs of Jerusalem artichoke ranged from 336 to 419gCkg(-1). Carbon sequestration in Jerusalem artichoke was higher in treatments with nitrogen fertilization compared to the CK treatment. The highest carbon sequestration was found in the N2 treatment. Soil carbon content was higher in the 0-10cm than 10-20cm layer, with nitrogen fertilization increasing carbon content in both soil layers. The highest soil carbon sequestration was measured in the N2 treatment. Carbon sequestration in both soil and Jerusalem artichoke residue was increased by nitrogen fertilization depending on the rates in the coastal saline zone studied. PMID:27317133

  14. QTL mapping in white spruce: gene maps and genomic regions underlying adaptive traits across pedigrees, years and environments

    PubMed Central

    2011-01-01

    Background The genomic architecture of bud phenology and height growth remains poorly known in most forest trees. In non model species, QTL studies have shown limited application because most often QTL data could not be validated from one experiment to another. The aim of our study was to overcome this limitation by basing QTL detection on the construction of genetic maps highly-enriched in gene markers, and by assessing QTLs across pedigrees, years, and environments. Results Four saturated individual linkage maps representing two unrelated mapping populations of 260 and 500 clonally replicated progeny were assembled from 471 to 570 markers, including from 283 to 451 gene SNPs obtained using a multiplexed genotyping assay. Thence, a composite linkage map was assembled with 836 gene markers. For individual linkage maps, a total of 33 distinct quantitative trait loci (QTLs) were observed for bud flush, 52 for bud set, and 52 for height growth. For the composite map, the corresponding numbers of QTL clusters were 11, 13, and 10. About 20% of QTLs were replicated between the two mapping populations and nearly 50% revealed spatial and/or temporal stability. Three to four occurrences of overlapping QTLs between characters were noted, indicating regions with potential pleiotropic effects. Moreover, some of the genes involved in the QTLs were also underlined by recent genome scans or expression profile studies. Overall, the proportion of phenotypic variance explained by each QTL ranged from 3.0 to 16.4% for bud flush, from 2.7 to 22.2% for bud set, and from 2.5 to 10.5% for height growth. Up to 70% of the total character variance could be accounted for by QTLs for bud flush or bud set, and up to 59% for height growth. Conclusions This study provides a basic understanding of the genomic architecture related to bud flush, bud set, and height growth in a conifer species, and a useful indicator to compare with Angiosperms. It will serve as a basic reference to functional and

  15. Formation, Excitation and Destruction of CH+ under the Influence of Water and Irradiation in Star Forming Regions

    NASA Astrophysics Data System (ADS)

    Benz, Arnold O.; Simon, Bruderer; van Dishoeck, Ewine

    2015-08-01

    Simple ionized hydrides were observed for the first time with Herschel/HIFI towards young star-forming objects of low to high mass. Of particular interest is CH+, a fundamental precursor molecule for carbon hydrides. Gaseous H2O reduces the abundance of C and C+, the starting products of CH+. The abundances of H2O and CH+ cannot be enhanced at the same place. Strong irradiation by FUV or X-rays reduces H2O, and CH+ gets more abundant. Thus CH+ signals high irradiation, but low H2O abundance.CH+ was observed to be enhanced in most objects to an abundance of typically 10-10 relative to hydrogen. This suggests an internal source of irradiation. The observed ratio of CH+/OH+ is consistent with irradiation by far UV as expected from chemical modelling. For low-mass objects the required FUV flux is between 1 - 200 times the ISRF at the location of the molecules. If the FUV flux originates at the central protostar, an FUV luminosity up to 1.5 Lsun is required. The UV flux in two high-mass objects is 30 and 90 times the ISRF using absorption lines, and of the order of 500 ISRF using emission lines. It is smaller than the unattenuated flux expected from the central object(s). The observed CH+/OH+ ratio, and other ratios such as OH+/H2O+ and CH+/C+, can only be modelled for low molecular hydrogen densities.The targeted lines of CH+, OH+, H2O+, and C+ are detected mostly in blue-shifted absorption. They are proposed to origin in FUV irradiated cavity walls that are shocked by the disk wind. The shock region is turbulent, broadening the lines to some 1 - 12 km/s. It is driven by the outward motion of the wind to blue shifts of 0 to -10 km/s. The blue-shifted H2O emission line (Kristensen et al. 2013) may be related but not coincident with the CH+ emitting region.

  16. Diversity between shell-like and beam-like regions for a cantilever cylindrical shell under follower forces

    NASA Astrophysics Data System (ADS)

    Torki, Mohammad Ebrahim; Kazemi, Mohammad Taghi; Mahmoudkhani, Saied

    2012-12-01

    The effect of length and thickness on dynamic stability analysis of cantilever cylindrical shells under follower forces is addressed. Beck's, Leipholz's, and Hauger's problems were solved for cylindrical shells with different length-to-radius and thicknesses-to-radius ratios using the Galerkin method. First-order shear theory was used, and rotary inertias were considered in deriving the differential equations. Critical circumferential and longitudinal mode numbers and loads were evaluated for each case. Diagrams containing nondimensional load parameters vs. length and thickness parameters were plotted for each problem. For some shells with small length-to-radius ratios, flutter occurred in high longitudinal mode numbers where the first-order shear theory may not suffice to accurately evaluate the deformations. However, for long and moderately thick shells, there are ranges in which the shell can be analyzed using the simplified equivalent beam model.

  17. Research on critical groundwater level under the threshold value of land subsidence in the typical region of Beijing

    NASA Astrophysics Data System (ADS)

    Jiang, Y.; Liu, J.-R.; Luo, Y.; Yang, Y.; Tian, F.; Lei, K.-C.

    2015-11-01

    Groundwater in Beijing has been excessively exploited in a long time, causing the groundwater level continued to declining and land subsidence areas expanding, which restrained the economic and social sustainable development. Long years of study show good time-space corresponding relationship between groundwater level and land subsidence. To providing scientific basis for the following land subsidence prevention and treatment, quantitative research between groundwater level and settlement is necessary. Multi-linear regression models are set up by long series factual monitoring data about layered water table and settlement in the Tianzhu monitoring station. The results show that: layered settlement is closely related to water table, water level variation and amplitude, especially the water table. Finally, according to the threshold value in the land subsidence prevention and control plan of China (45, 30, 25 mm), the minimum allowable layered water level in this region while settlement achieving the threshold value is calculated between -18.448 and -10.082 m. The results provide a reasonable and operable control target of groundwater level for rational adjustment of groundwater exploited horizon in the future.

  18. Circadian and homeostatic modulation of functional connectivity and regional cerebral blood flow in humans under normal entrained conditions

    PubMed Central

    Hodkinson, Duncan J; O'Daly, Owen; Zunszain, Patricia A; Pariante, Carmine M; Lazurenko, Vitaly; Zelaya, Fernando O; Howard, Matthew A; Williams, Steven C R

    2014-01-01

    Diurnal rhythms have been observed in human behaviors as diverse as sleep, olfaction, and learning. Despite its potential impact, time of day is rarely considered when brain responses are studied by neuroimaging techniques. To address this issue, we explicitly examined the effects of circadian and homeostatic regulation on functional connectivity (FC) and regional cerebral blood flow (rCBF) in healthy human volunteers, using whole-brain resting-state functional magnetic resonance imaging (rs-fMRI) and arterial spin labeling (ASL). In common with many circadian studies, we collected salivary cortisol to represent the normal circadian activity and functioning of the hypothalamic–pituitary–adrenal (HPA) axis. Intriguingly, the changes in FC and rCBF we observed indicated fundamental decreases in the functional integration of the default mode network (DMN) moving from morning to afternoon. Within the anterior cingulate cortex (ACC), our results indicate that morning cortisol levels are negatively correlated with rCBF. We hypothesize that the homeostatic mechanisms of the HPA axis has a role in modulating the functional integrity of the DMN (specifically, the ACC), and for the purposes of using fMRI as a tool to measure changes in disease processes or in response to treatment, we demonstrate that time of the day is important when interpreting resting-state data. PMID:24938404

  19. Correlation between Focal Nodular Low Signal Changes in Hoffa's Fat Pad Adjacent to Anterior Femoral Cartilage and Focal Cartilage Defect Underlying This Region and Its Possible Implication

    PubMed Central

    Ng, Wuey Min

    2016-01-01

    Purpose. This study investigates the association between focal nodular mass with low signal in Hoffa's fat pad adjacent to anterior femoral cartilage of the knee (FNMHF) and focal cartilage abnormality in this region. Method. The magnetic resonance fast imaging employing steady-state acquisition sequence (MR FIESTA) sagittal and axial images of the B1 and C1 region (described later) of 148 patients were independently evaluated by two reviewers and categorized into four categories: normal, FNMHF with underlying focal cartilage abnormality, FNMHF with normal cartilage, and cartilage abnormality with no FNMHF. Results. There was a significant association (p = 0.00) between FNMHF and immediate adjacent focal cartilage abnormality with high interobserver agreement. The absence of focal nodular lesions next to the anterior femoral cartilage has a very high negative predictive value for chondral injury (97.8%). Synovial biopsy of focal nodular lesion done during arthroscopy revealed some fibrocollagenous tissue and no inflammatory cells. Conclusion. We postulate that the FNMHF adjacent to the cartilage defects is a form of normal healing response to the cartilage damage. One patient with FHMHF and underlying cartilage abnormality was rescanned six months later. In this patient, the FNMHF disappeared and normal cartilage was observed in the adjacent region which may support this theory. PMID:27213085

  20. Human brain mapping under increasing cognitive complexity using regional cerebral blood flow measurements and positron emission tomography.

    PubMed

    Law, Ian

    2007-11-01

    Measurement of the regional cerebral blood flow (rCBF) is an important parameter in the evaluation of cerebral function. With positron emission tomography (PET) rCBF has predominantly been quantified using the short-lived radiotracer oxygen-15 labelled water (H 2 15 O) and an adaptation of the Kety one-tissue compartment autoradiographic model. The values attained in putative grey matter, however, are systematically underestimated because of the limited scanner resolution. For this reason we applied a dynamic kinetic two-tissue compartment model including a fast and a slow flow component each with a perfusable tissue fraction. In the fast component rCBF was 2-2.5 times greater than grey matter values using traditional autoradiography in both human and monkey. Visual stimulation in human gave a corrected rCBF increase of approximately 40%. Visual stimulation was also used to indirectly validate carbon-10 labelled carbondioxide ( 10 CO 2 ), a new very short-lived rCBF PET tracer with a half-life of only 19.3 seconds. This allowed an increase in the number of independent PET scans per subject from 12-14 using H 2 15 O to 64 using 10 CO 2 . The experiment demonstrated a maximal activation response in the visual cortex at a 10-15 Hz stimulation frequency. The use of the rCBF PET mapping technique is illustrated by studies of the organization of language and the oculomotor system. With respect to the former, we found confirmation of neuropsychological evidence of the involvement of the left supramarginal/angular gyrus in reading in Japanese of a phonologically based script system, Kana, and of the left posterior inferior temporal gyrus in reading of a morphogram based script system, Kanji. Concerning the organization of the oculomotor system we found overlapping areas in fronto-parietal cortex involved in maintaining visual fixation, and performing visually guided and imagined eye movements. These data show that overt eye movements are not a prerequisite of the

  1. Land cover and land use changes in the oil and gas regions of Northwestern Siberia under changing climatic conditions

    NASA Astrophysics Data System (ADS)

    Yu, Qin; Epstein, Howard E.; Engstrom, Ryan; Shiklomanov, Nikolay; Strelestskiy, Dmitry

    2015-12-01

    Northwestern Siberia has been undergoing a range of land cover and land use changes associated with climate change, animal husbandry and development of mineral resources, particularly oil and gas. The changes caused by climate and oil/gas development Southeast of the city of Nadym were investigated using multi-temporal and multi-spatial remotely sensed images. Comparison between high spatial resolution imagery acquired in 1968 and 2006 indicates that 8.9% of the study area experienced an increase in vegetation cover (e.g. establishment of new saplings, extent of vegetated cover) in response to climate warming while 10.8% of the area showed a decrease in vegetation cover due to oil and gas development and logging activities. Waterlogging along linear structures and vehicle tracks was found near the oil and gas development site, while in natural landscapes the drying of thermokarst lakes is evident due to warming caused permafrost degradation. A Landsat time series dataset was used to document the spatial and temporal dynamics of these ecosystems in response to climate change and disturbances. The impacts of land use on surface vegetation, radiative, and hydrological properties were evaluated using Landsat image-derived biophysical indices. The spatial and temporal analyses suggest that the direct impacts associated with infrastructure development were mostly within 100 m distance from the disturbance source. While these impacts are rather localized they persist for decades despite partial recovery of vegetation after the initial disturbance and can have significant implications for changes in permafrost dynamics and surface energy budgets at landscape and regional scales.

  2. Soil erosion under climate change in Great Britain: long-term simulations using high-resolution regional models

    NASA Astrophysics Data System (ADS)

    Ciampalini, Rossano; Kendon, Elizabeth; Constantine, José Antonio; Schindewolf, Marcus; Hall, Ian

    2016-04-01

    Twenty-first century climate change simulations for Great Britain reveal an increase in heavy precipitation that may lead to widespread soil loss and reduced soil carbon stores by increasing the likelihood of surface runoff. We find the quality and resolution of the simulated rainfall used to drive soil loss variation can widely influence the results. Hourly high definition rainfall simulations from a 1.5km resolution regional climate model are used to examine the soil erosion response in two UK catchments. The catchments have different sensitivity to soil erosion. "Rother" in West Sussex, England, reports some of the most erosive events that have been observed during the last 50 years in the UK. "Conwy" in North Wales, is resilient to soil erosion because of the abundant natural vegetation cover and very limited agricultural practises. We modelled with Erosion3D to check variations in soil erosion as influenced by climate variations for the periods 1996-2009 and 2086-2099. Our results indicate the Rother catchment is the most erosive, while the Conwy catchment is confirmed as the more resilient to soil erosion. The values of the reference-base period are consistent with the values of those locally observed in the previous decades. A soil erosion comparison for the two periods shows an increasing of sediment production (off-site erosion) for the end of the century at about 27% in the Rother catchment and about 50% for the Conwy catchment. The results, thanks to high-definition rainfall predictions, throw some light on the effect of climatic change effects in Great Britain.

  3. [Dynamics of regional ecological frangibility under natural hazard stress: a case study in Qingping Town of Sichuan Province, Southwest China].

    PubMed

    Liu, Bin-Tao; Tao, He-Ping; Liu, Shao-Quan; Yu, Hui; Kong, Bo

    2012-01-01

    By using the aerial remote sensing images after May 12, 2008 (the date of catastrophic Wenchuan Earthquake) and the unmanned aircraft vehicle remote sensing images after August 13, 2010 (the date of extraordinary debris flow), and in combining with the land use map (1:10000), topographic map (1:50000), and collected field investigation data of Qingping Town, Mianzhu City of Sichuan Province in 2006, this paper analyzed and evaluated the ecological frangibility of the Town. In the Town, the slightly, lightly, moderately, heavily, and extremely fragile ecological zones after the extraordinary debris flow occupied 1.9%, 7.9%, 18.7%, 23.0%, and 48.5%, respectively, with the area of heavily and extremely fragile ecological zones accounting for 71.5% of the total, being 238.45 km2, i. e., the ecological environment was overall very fragile. Under the impact of the two natural hazards, the ecological frangibility degree of the Town increased obviously. As compared with that before the Earthquake, the area of heavily and extremely fragile ecological zones after the Earthquake increased by 12.4%, and the area of extremely fragile ecological zone was 1.67 times larger. The dynamic evolution of the ecological frangibility of the Town was mainly manifested in the conversion of heavily fragile ecological zone into extremely fragile ecological zone. Complex terrain was the key factor of the ecological frangibility of the Town. PMID:22489499

  4. Time-Course Analysis of Brain Regional Expression Network Responses to Chronic Intermittent Ethanol and Withdrawal: Implications for Mechanisms Underlying Excessive Ethanol Consumption

    PubMed Central

    Smith, Maren L.; Lopez, Marcelo F.; Archer, Kellie J.; Wolen, Aaron R.; Becker, Howard C.; Miles, Michael F.

    2016-01-01

    Long lasting abusive consumption, dependence, and withdrawal are characteristic features of alcohol use disorders (AUD). Mechanistically, persistent changes in gene expression are hypothesized to contribute to brain adaptations leading to ethanol toxicity and AUD. We employed repeated chronic intermittent ethanol (CIE) exposure by vapor chamber as a mouse model to simulate the cycles of ethanol exposure and withdrawal commonly seen with AUD. This model has been shown to induce progressive ethanol consumption in rodents. Brain CIE-responsive expression networks were identified by microarray analysis across five regions of the mesolimbic dopamine system and extended amygdala with tissue harvested from 0-hours to 7-days following CIE. Weighted Gene Correlated Network Analysis (WGCNA) was used to identify gene networks over-represented for CIE-induced temporal expression changes across brain regions. Differential gene expression analysis showed that long-lasting gene regulation occurred 7-days after the final cycle of ethanol exposure only in prefrontal cortex (PFC) and hippocampus. Across all brain regions, however, ethanol-responsive expression changes occurred mainly within the first 8-hours after removal from ethanol. Bioinformatics analysis showed that neuroinflammatory responses were seen across multiple brain regions at early time-points, whereas co-expression modules related to neuroplasticity, chromatin remodeling, and neurodevelopment were seen at later time-points and in specific brain regions (PFC or HPC). In PFC a module containing Bdnf was identified as highly CIE responsive in a biphasic manner, with peak changes at 0 hours and 5 days following CIE, suggesting a possible role in mechanisms underlying long-term molecular and behavioral response to CIE. Bioinformatics analysis of this network and several other modules identified Let-7 family microRNAs as potential regulators of gene expression changes induced by CIE. Our results suggest a complex temporal

  5. Time-Course Analysis of Brain Regional Expression Network Responses to Chronic Intermittent Ethanol and Withdrawal: Implications for Mechanisms Underlying Excessive Ethanol Consumption.

    PubMed

    Smith, Maren L; Lopez, Marcelo F; Archer, Kellie J; Wolen, Aaron R; Becker, Howard C; Miles, Michael F

    2016-01-01

    Long lasting abusive consumption, dependence, and withdrawal are characteristic features of alcohol use disorders (AUD). Mechanistically, persistent changes in gene expression are hypothesized to contribute to brain adaptations leading to ethanol toxicity and AUD. We employed repeated chronic intermittent ethanol (CIE) exposure by vapor chamber as a mouse model to simulate the cycles of ethanol exposure and withdrawal commonly seen with AUD. This model has been shown to induce progressive ethanol consumption in rodents. Brain CIE-responsive expression networks were identified by microarray analysis across five regions of the mesolimbic dopamine system and extended amygdala with tissue harvested from 0-hours to 7-days following CIE. Weighted Gene Correlated Network Analysis (WGCNA) was used to identify gene networks over-represented for CIE-induced temporal expression changes across brain regions. Differential gene expression analysis showed that long-lasting gene regulation occurred 7-days after the final cycle of ethanol exposure only in prefrontal cortex (PFC) and hippocampus. Across all brain regions, however, ethanol-responsive expression changes occurred mainly within the first 8-hours after removal from ethanol. Bioinformatics analysis showed that neuroinflammatory responses were seen across multiple brain regions at early time-points, whereas co-expression modules related to neuroplasticity, chromatin remodeling, and neurodevelopment were seen at later time-points and in specific brain regions (PFC or HPC). In PFC a module containing Bdnf was identified as highly CIE responsive in a biphasic manner, with peak changes at 0 hours and 5 days following CIE, suggesting a possible role in mechanisms underlying long-term molecular and behavioral response to CIE. Bioinformatics analysis of this network and several other modules identified Let-7 family microRNAs as potential regulators of gene expression changes induced by CIE. Our results suggest a complex temporal

  6. Role of atmospheric heating over the South China Sea and western Pacific regions in modulating Asian summer climate under the global warming background

    NASA Astrophysics Data System (ADS)

    He, Bian; Yang, Song; Li, Zhenning

    2016-05-01

    The response of monsoon precipitation to global warming, which is one of the most significant climate change signals at the earth's surface, exhibits very distinct regional features, especially over the South China Sea (SCS) and adjacent regions in boreal summer. To understand the possible atmospheric dynamics in these specific regions under the global warming background, changes in atmospheric heating and their possible influences on Asian summer climate are investigated by both observational diagnosis and numerical simulations. Results indicate that heating in the middle troposphere has intensified in the SCS and western Pacific regions in boreal summer, accompanied by increased precipitation, cloud cover, and lower-tropospheric convergence and decreased sea level pressure. Sensitivity experiments show that middle and upper tropospheric heating causes an east-west feedback pattern between SCS and western Pacific and continental South Asia, which strengthens the South Asian High in the upper troposphere and moist convergence in the lower troposphere, consequently forcing a descending motion and adiabatic warming over continental South Asia. When air-sea interaction is considered, the simulation results are overall more similar to observations, and in particular the bias of precipitation over the Indian Ocean simulated by AGCMs has been reduced. The result highlights the important role of air-sea interaction in understanding the changes in Asian climate.

  7. Short-term effects of fertility management under organic farming in Mediterranean region on soil properties and tomato production

    NASA Astrophysics Data System (ADS)

    Cavoski, Ivana; Chami, Ziad Al; Jarrar, Mohammad; Dumontet, Stefano; Mondelli, Donato

    2014-05-01

    In organic farming, plant production depends almost exclusively on nutrient deriving from the decomposition of exogenous organic matter in soil which is able to provide significant quantities of several important nutrients for the plant growth. However, in the soil the timing and amount of mineralization often does not coincide with crop nutritional need, making in-season fertilization necessary. The Regulation (EC) No 889/2008 on organic farming standards recognizes these needs and allows the use of a limited range fertilizers and soil conditioners (inputs) in order to meet nutritional needs of the plants and to achieve short term economically viable yield. Short-term open field experiment was conducted at the Mediterranean Agronomic Institute of Bari (MAIB) located in Apulia region (Southern Italy) in order study the effects of different fertilization scenarios based on equilibrated nutritional requirement on tomato (Lycopersicon esculentum Mill, cv. San Marzano) production efficiency and soil chemical properties. In soil dressing phase, three months before planting, biochar (BCH), organic fertilizers (OF), combined treatment (BCH+OF), cattle manure and vineyard wood compost (MVC), dairy wastes industry and vineyard wood compost (DVC) and unamended soil as control (CON) were established. In the pre-crop phase, organic and/or mineral fertilizers were incorporated into the previous treatments except CON and BCH in order to achieve balanced N, P and K application rates for tomato plants. Different fertilization scenarios significantly increased the yields over CON and BCH treatments, maintaining fruits quality. In short period of time, most of the soil parameters remained invariable, only available phosphorus significantly increased in the treatments which received organic fertilizers maybe due to the slight reduction in soil pH. However, such results are not surprising, if we consider the quantity of amendments and fertilizers applied in the experiment, as well as

  8. Assessment of carbon pools in two soils from the Campania region (Southwest, Italy) under different forest types

    NASA Astrophysics Data System (ADS)

    Álvarez-Romero, Marta; Papa, Stefania; Lozano-García, Beatriz; Parras-Alcántara, Luis; González-Pérez, José A.; Jordán, Antonio; Zavala, Lorena M.; González-Vila, Francisco J.; Coppola, Elio

    2014-05-01

    Soil is the largest carbon reservoir of terrestrial ecosystems, this reservoir is not inert, but it is constantly in a dynamic phase of accumulation an depletion. After the addition, in the soil, of organic residues of different origin and nature, two processes can occur in charge of SOM (Soil Organic Matter) during the pedogenesis: mineralization and humification. The accumulation of SOM in soil is controlled by the balance between carbon inputs and losses through mineralization and/or leaching. In particular the humification process leads to the formation of organic compounds (in some cases even complex organo-mineral) chemically stable able to distribute itself in the soil second rules of site-specific pedogenesis. The transport process along the profile can take very different forms which may extend in the formation of Bh horizons of accumulation in depth also strongly cemented (so-called ortstein). The transport process along the profile occurs for the occurrence of certain conditions such as deposition of high amounts of organic residues on the top of the profile, high porosity of the soil for the presence of coarse solid fractions (coarse sands or skeleton) that determinate a strong infiltrating capacity of the circulating waters, extreme temperatures can slow or stop the process of mineralization and/or humification in one intermediate step of the degradation process releasing organic metabolites with high or medium solubility and high loads of percolating water related to intense rainfall. The nature of the forest cover influence the quantity and quality of the organic materials deposited with marked differences between coniferous and deciduous especially in relation to resistance to degradation and production of intermediate metabolites. Two soils from Campania region located in Monte Santa Croce (Caserta, Italy) with andic properties, different forest cover (pine and chestnut) and that meets the requirements of the place and pedological formation

  9. Overheating risk assessment of naturally ventilated classroom under the influence of climate change in hot and humid region

    NASA Astrophysics Data System (ADS)

    Huang, Kuo-Tsang

    2013-04-01

    Natural ventilation (NV) is considered one of the passive building strategies used for reducing cooling energy demand. The utilization of nature wind for cooling down indoor thermal environment to reach thermal comfort requires knowledge of adequately positioning the building fenestrations, designing inlet-outlet related opening ratios, planning unobstructed cross ventilation paths, and, the most important, assessing the utilization feasibility base on local climatic variables. Furthermore, factors that influence the indoor thermal condition include building envelope heat gain, indoor air velocity, indoor heat gain (e.g. heat discharges from occupant's body, lighting fixture, electrical appliances), and outdoor climate. Among the above, the indoor thermal performance of NV building is significantly dependent to outdoor climate conditions. In hot and humid Taiwan, under college school classrooms are usually operated in natural ventilation mode and are more vulnerable to climate change in regard to maintain indoor thermal comfort. As climate changes in progress, NV classrooms would expect to encounter more events of overheating in the near future, which result in more severe heat stress, and would risk the utilization of natural ventilation. To evaluate the overheating risk under the influence of recent climate change, an actual top floor elementary school classroom with 30 students located at north Taiwan was modeled. Long-term local hourly meteorological data were gathered and further constructed into EnergyPlus Weather Files (EPWs) format for building thermal dynamic simulation to discuss the indoor thermal environmental variation during the period of 1998 to 2012 by retrospective simulation. As indoor thermal environment is an overall condition resulting from a series combination of various factors, sub-hourly building simulation tool, EnergyPlus, coupled with the above fifteen years' EPWs was adopted to predict hourly indoor parameters of mean radiant

  10. Contribution of the aquitard to the regional groundwater hydrochemistry of the underlying confined aquifer in the Pearl River Delta, China.

    PubMed

    Wang, Ya; Jiao, Jiu Jimmy; Cherry, John A; Lee, Chun Ming

    2013-09-01

    Aquitards are capable of generating and preserving large amounts of chemicals. The release of the chemicals from the aquitards poses a potential contamination risk to groundwater that may be used as a drinking water source. This work aimed to identify the contribution of hydrogeochemical processes in the aquitards to groundwater hydrochemistry in the underlying confined basal aquifer by studying the coastal Quaternary aquifer-aquitard system of the Pearl River Delta, China. The system was submerged by paleo-seawater in the early Holocene and mainly receives infiltration of precipitation at present, as indicated by investigations on stable isotopes (δ(2)H, δ(18)O), water chemistry (SO4(2-) and Cl(-)) and salinity. Significant correlations between total dissolved solids in the basal aquifer and the thickness of the overlying aquitard further suggested the contribution of the aquitard to the groundwater hydrochemistry in the aquifer. Significant correlations between the chloride concentrations in aquitard porewater and that in groundwater in the aquifer, and between the thickness of the aquitard and the chloride concentrations in groundwater indicated the strong influence of the aquitard on the chloride in the aquifer. This is probably because the low-permeability aquitard is capable of preserving the paleo-seawater in the aquifer and releasing the salinity from the aquitard down to the aquifer via downward flow or diffusion. Isotopic and geochemical studies revealed that the aquitard is also responsible for generating and preserving large amounts of naturally occurring ammonium. Analysis between the concentrations of ammonium in groundwater in the basal aquifer and the total available ammonium in aquitard sediments suggested that the former is significantly controlled by the latter. PMID:23770547

  11. Response of nitrogen and potassium fertigation to "Waris" almond (Prunus dulcis) under northwestern Himalayan Region of India.

    PubMed

    Kumar, Dinesh; Ahmed, N

    2014-01-01

    A field experiment was conducted on almond (Prunus dulcis) to study the effect of N&K fertigation on growth, yields and leaf nutrient status over two seasons (2011 and 2012) in Srinagar, Jammu and Kashmir, India. There were six treatments, namely, T1--100% recommended dose of fertilizers as soil application, T2--100% RDF through fertigations, T3--75% RDF through fertigation, T4--75% RDF through fertigation (split application), T5--50% RDF through fertigation and T6--50% RDF through fertigation (split application) with three replications under randomized block design. The results indicated that the maximum tree height (3.21 m and 3.56 m), nut weight (2.73 g and 1.94 g), nut yield (2.41 kg/tree and 5.98 kg/tree; 2.67 t/ha and 6.64 t/ha), and leaf nutrient content (2.34 and 2.38% N; 0.14 and 0.17% P; 1.37 and 1.41% K) were recorded in T4 treatment, whereas the highest TCSA of main trunk, primary, secondary, and tertiary branches (72.67 and 90.28 cm(2); 16.75 and 24.26 cm(2); 3.83 and 7.49 cm(2); 0.47 and 1.23 cm(2)), canopy volume (7.15 and 8.11 m(3)), and fruit number (990 and 3083/tree) were recorded in T2 in almond variety Waris. PMID:24587708

  12. Sediment sources of Yan'gou watershed in the Loess Hilly region China under a certain rainstorm event.

    PubMed

    Xu, Xue-Xuan; Ju, Tong-Jun; Zheng, Shi-Qing

    2013-01-01

    At present the large scale vegetation restoration and intensive oil exploiting had brought huge influence on local environment in Yan'an region. the sediment yield data form series experiment plots and hydrological monitoring station in the Yan'an watershed after one rainfall event on July 2, 2005, which included sediment from different land uses (crop-land plot, vegetation plots, hard road surface) and 3 types roads(mountain-road brunches, mountain-road, and mountain-transport way) has been analyzed. Results showed that the erosion intensity of the 3 type roads was respectively 500 t/km(2), 3163 t/km(2), and 13500 t/km(2). The sediment from cropland and grass, shrub land was within 6-184 t/km(2). It stated that sediment from road area which only covered 1% of total area accounted for 42.3% of the total sediment yield, far beyond that from other uses of land. Sediment from grass-land and shrub-land, which covered 70.5% of watershed area, shared 26.7% of the total sediment. The further analysis showed that the 41.2% of total sediment could be detained by re-vegetation. On the contrary, that road constructing brought heavy sediment which offset the benefit of vegetation restore by 58.4%. the suggestion were to adjust our strategy from slope management to the road erosion mitigation Many studies have confirmed it is an important measure to return the steep slope farming land to green, and to restore vegetation in line with local conditions to prevent soil erosion in the Loess Plateau [1, 2]. To implement the measure in western region, the researches on "Grain for Green", returning farmland to forest and grassland, has become popular [3, 4]. Many scholars studied the effects of farming land and trees and grass land on soil water storage [2, 5]. Tang Keli stated that the slope land for farming was the main source of the sediment in Yellow river, and the maximum gradient slope for farming land use was 25° [6]. Many authorities not only pointed out that a far

  13. Air-quality in the mid-21st century for the city of Paris under two climate scenarios; from regional to local scale

    NASA Astrophysics Data System (ADS)

    Markakis, K.; Valari, M.; Colette, A.; Sanchez, O.; Perrussel, O.; Honore, C.; Vautard, R.; Klimont, Z.; Rao, S.

    2014-01-01

    Ozone and PM2.5 concentrations over the city of Paris are modeled with the CHIMERE air-quality model at 4 km × 4 km horizontal resolution for two future emission scenarios. High-resolution (1 km × 1 km) emission projection until 2020 for the greater Paris region is developed by local experts (AIRPARIF) and is further extended to year 2050 based on regional scale emission projections developed by the Global Energy Assessment. Model evaluation is performed based on a 10 yr control simulation. Ozone is in very good agreement with measurements while PM2.5 is underestimated by 20% over the urban area mainly due to a large wet bias in wintertime precipitation. A significant increase of maximum ozone relative to present time levels over Paris is modeled under the "business as usual" scenario (+7 ppb) while a more optimistic mitigation scenario leads to moderate ozone decrease (-3.5 ppb) in year 2050. These results are substantially different to previous regional scale projections where 2050 ozone is found to decrease under both future scenarios. A sensitivity analysis showed that this difference is due to the fact that ozone formation over Paris at the current, urban scale study, is driven by VOC-limited chemistry, whereas at the regional scale ozone formation occurs under NOx-sensitive conditions. This explains why the sharp NOx reductions implemented in the future scenarios have a different effect on ozone projections at different scales. In rural areas projections at both scales yield similar results showing that the longer time-scale processes of emission transport and ozone formation are less sensitive to model resolution. PM2.5 concentrations decrease by 78% and 89% under "business as usual" and "mitigation" scenarios respectively compared to present time period. The reduction is much more prominent over the urban part of the domain due to the effective reductions of road transport and residential emissions resulting in the smoothing of the large urban increment

  14. Air quality in the mid-21st century for the city of Paris under two climate scenarios; from the regional to local scale

    NASA Astrophysics Data System (ADS)

    Markakis, K.; Valari, M.; Colette, A.; Sanchez, O.; Perrussel, O.; Honore, C.; Vautard, R.; Klimont, Z.; Rao, S.

    2014-07-01

    Ozone and PM2.5 concentrations over the city of Paris are modeled with the CHIMERE air-quality model at 4 km × 4 km horizontal resolution for two future emission scenarios. A high-resolution (1 km × 1 km) emission projection until 2020 for the greater Paris region is developed by local experts (AIRPARIF) and is further extended to year 2050 based on regional-scale emission projections developed by the Global Energy Assessment. Model evaluation is performed based on a 10-year control simulation. Ozone is in very good agreement with measurements while PM2.5 is underestimated by 20% over the urban area mainly due to a large wet bias in wintertime precipitation. A significant increase of maximum ozone relative to present-day levels over Paris is modeled under the "business-as-usual" scenario (+7 ppb) while a more optimistic "mitigation" scenario leads to a moderate ozone decrease (-3.5 ppb) in year 2050. These results are substantially different to previous regional-scale projections where 2050 ozone is found to decrease under both future scenarios. A sensitivity analysis showed that this difference is due to the fact that ozone formation over Paris at the current urban-scale study is driven by volatile organic compound (VOC)-limited chemistry, whereas at the regional-scale ozone formation occurs under NOx-sensitive conditions. This explains why the sharp NOx reductions implemented in the future scenarios have a different effect on ozone projections at different scales. In rural areas, projections at both scales yield similar results showing that the longer timescale processes of emission transport and ozone formation are less sensitive to model resolution. PM2.5 concentrations decrease by 78% and 89% under business-as-usual and mitigation scenarios, respectively, compared to the present-day period. The reduction is much more prominent over the urban part of the domain due to the effective reductions of road transport and residential emissions resulting in the

  15. Evolutionary and Structural Features of the C2, V3 and C3 Envelope Regions Underlying the Differences in HIV-1 and HIV-2 Biology and Infection

    PubMed Central

    Bártolo, Inês; Marcelino, José Maria; Família, Carlos; Quintas, Alexandre; Taveira, Nuno

    2011-01-01

    Background Unlike in HIV-1 infection, the majority of HIV-2 patients produce broadly reactive neutralizing antibodies, control viral replication and survive as elite controllers. The identification of the molecular, structural and evolutionary footprints underlying these very distinct immunological and clinical outcomes may lead to the development of new strategies for the prevention and treatment of HIV infection. Methodology/Principal Findings We performed a side-by-side molecular, evolutionary and structural comparison of the C2, V3 and C3 envelope regions from HIV-1 and HIV-2. These regions contain major antigenic targets and are important for receptor binding. In HIV-2, these regions also have immune modulatory properties. We found that these regions are significantly more variable in HIV-1 than in HIV-2. Within each virus, C3 is the most entropic region followed by either C2 (HIV-2) or V3 (HIV-1). The C3 region is well exposed in the HIV-2 envelope and is under strong diversifying selection suggesting that, like in HIV-1, it may harbour neutralizing epitopes. Notably, however, extreme diversification of C2 and C3 seems to be deleterious for HIV-2 and prevent its transmission. Computer modelling simulations showed that in HIV-2 the V3 loop is much less exposed than C2 and C3 and has a retractile conformation due to a physical interaction with both C2 and C3. The concealed and conserved nature of V3 in the HIV-2 is consistent with its lack of immunodominancy in vivo and with its role in preventing immune activation. In contrast, HIV-1 had an extended and accessible V3 loop that is consistent with its immunodominant and neutralizing nature. Conclusions/Significance We identify significant structural and functional constrains to the diversification and evolution of C2, V3 and C3 in the HIV-2 envelope but not in HIV-1. These studies highlight fundamental differences in the biology and infection of HIV-1 and HIV-2 and in their mode of interaction with the human

  16. Cardiovascular responses to retigabine in conscious rats – under normotensive and hypertensive conditions

    PubMed Central

    Fretwell, L V; Woolard, J

    2013-01-01

    Background and Purpose Retigabine is a recently approved antiepileptic agent which activates Kv7.2–7.5 potassium channels. It is emerging that these channels have an important role in vascular regulation, but the vascular effects of retigabine in the conscious state are unknown. Hence, in the present study we assessed the regional haemodynamic responses to retigabine in conscious rats. Experimental Approach Male Sprague Dawley rats were chronically instrumented with pulsed Doppler flow probes to measure regional haemodynamic responses to retigabine under control conditions and during acute hypertension induced by infusion of angiotensin II and arginine vasopressin. Further experiments were performed, using the β-adrenoceptor antagonists CGP 20712A, ICI 118551 and propranolol, to elucidate the roles of β-adrenoceptors in the responses to retigabine in vivo and in vitro. Key Results Under normotensive conditions, retigabine induced dose-dependent hypotension and hindquarters vasodilatation, with small, transient renal and mesenteric vasodilatations. In the acutely hypertensive state, the renal and mesenteric, but not hindquarters, vasodilatations were enhanced. The response of the hindquarters vascular bed to retigabine was mediated, in part, by β2-adrenoceptors. However, in vitro experiments confirmed that retigabine did not act as a β-adrenoceptor agonist. Conclusions and Implications We demonstrated that retigabine causes regionally specific vasodilatations, which are different under normotensive and hypertensive conditions, and are, in part, mediated by β2-adrenoceptors in some vascular beds but not in others. These results broadly support previous findings and further indicate that Kv7 channels are a potential therapeutic target for the treatment of vascular diseases associated with inappropriate vasoconstriction. PMID:23581476

  17. The Unstructured N-terminal Region of Arabidopsis Group 4 Late Embryogenesis Abundant (LEA) Proteins Is Required for Folding and for Chaperone-like Activity under Water Deficit.

    PubMed

    Cuevas-Velazquez, Cesar L; Saab-Rincón, Gloria; Reyes, José Luis; Covarrubias, Alejandra A

    2016-05-13

    Late embryogenesis abundant (LEA) proteins are a conserved group of proteins widely distributed in the plant kingdom that participate in the tolerance to water deficit of different plant species. In silico analyses indicate that most LEA proteins are structurally disordered. The structural plasticity of these proteins opens the question of whether water deficit modulates their conformation and whether these possible changes are related to their function. In this work, we characterized the secondary structure of Arabidopsis group 4 LEA proteins. We found that they are disordered in aqueous solution, with high intrinsic potential to fold into α-helix. We demonstrate that complete dehydration is not required for these proteins to sample ordered structures because milder water deficit and macromolecular crowding induce high α-helix levels in vitro, suggesting that prevalent conditions under water deficit modulate their conformation. We also show that the N-terminal region, conserved across all group 4 LEA proteins, is necessary and sufficient for conformational transitions and that their protective function is confined to this region, suggesting that folding into α-helix is required for chaperone-like activity under water limitation. We propose that these proteins can exist as different conformers, favoring functional diversity, a moonlighting property arising from their structural dynamics. PMID:27006402

  18. Effects of summer heat stress on physiological variables, ovulation and progesterone secretion in Pelibuey ewes under natural outdoor conditions in an arid region.

    PubMed

    Macías-Cruz, Ulises; Gastélum, Miguel A; Álvarez, Francisco D; Correa, Abelardo; Díaz, Raúl; Meza-Herrera, César A; Mellado, Miguel; Avendaño-Reyes, Leonel

    2016-03-01

    Ten non-lactating multiparous Pelibuey breed ewes were housed in a corral to evaluate the effects of summer thermal stress on physiologic variables, estrous behavior, ovulation and corpus luteum functionality under natural conditions of an arid region. In summer and autumn, daily estrous detection with a ram fitted with an apron and blood sample collections were performed during two natural estrous cycles. An environment of heat stress was detected in summer and thermoneutral in autumn. Rectal temperature and respiratory frequency were greater (P < 0.01) in summer than in autumn during the morning and afternoon. Season did not affect (P > 0.05) live weight, body condition, length of estrous cycle or percentage of ewes in estrous and ovulating. Compared with autumn, serum progesterone concentrations in summer decreased (P < 0.05) between days 8 and 14 of the estrous cycle. It is concluded that under outdoor conditions of arid regions, while estrous and ovulatory activities of Pelibuey ewes were not affected by summer thermal stress, the corpus luteum functionality was decreased. PMID:26304696

  19. Markovian characteristics of dry spells over the Iberian Peninsula under present and future conditions using ESCENA ensemble of regional climate models

    NASA Astrophysics Data System (ADS)

    López-Franca, Noelia; Sánchez, Enrique; Losada, Teresa; Domínguez, Marta; Romera, Raquel; Gaertner, Miguel Ángel

    2015-08-01

    The study analyses the annual structure of dry spells over the Iberian Peninsula through a second markov chain model based on the persistence concept under present and future conditions. The persistence of dryness can be considered as an indicator of drought, being useful for early warning drought systems. It can be studied as an isolated factor, here we focus the analysis on the probability of dry spells occurrence at each grid point of the domain by means of a two-state second order of Markov Chain model. Previous studies using this model along twentieth century observational data obtained successful results in the dry spells characterisation over several regions. First, the application of this theoretical model on three observational datasets over the domain, confirms the second order of markov chain characteristics of the observed dry spells. Then, the observational climate (1989-2007) EraInterim-forced regional climate model simulations from Spanish ESCENA project are successfully compared with those observational datasets results. Then, the study of climate change projections on the markovian behaviour is studied through the ECHAM5r2 global climate model and the regional models under present (1970-2000) and future (2021-2050) climate conditions. They indicate that the markovian characteristics of dry spells are kept in the future over the domain except some points in the South East coast. A decrease of the probability of occurrence of short dry spells (1-7 days) is obtained, while the longest dry spells (>12 days) are increased. These results are coherent with the analysis of the annual average of dry spells length.

  20. Cerebral vasoconstriction reactions and plasma levels of ETBR, ET-1, and eNOS in patients with chronic high altitude disease

    PubMed Central

    Wu, Shizheng; Hao, Guisheng; Zhang, Shukun; Jiang, Dongmei; Wuren, Tana; Luo, Junming

    2016-01-01

    The aim of the present study was to examine cerebral vasoconstriction in patients with chronic high altitude disease [cerebrovascular reactivity (CVR)], and to evaluate differences in alterations of brain vascular contractile reactivity of chronic mountain sickness (CMS) patients and healthy controls. Alterations of endothelin (ET) and its receptor, as well as endothelial nitric oxide synthase (eNOS) levels in the plasma were examined to determine the cerebral reservation capacities in CMS patients. Transcranial Doppler ultrasound and carbon dioxide analysis methods were used to detect the CVR variances. At the same time, enzyme-linked immunosorbent assay approaches were utilized to detect the ET and ET B receptor and the eNOS levels in serum of the CMS patients and healthy controls. CVR and CVRI levels in CMS patients were lower than those of the healthy control subjects and the difference was statistically significant (P<0.05). By contrast, eNOS and ET-1 levels were not statistically significant for CMS and healthy controls (P>0.05). However, the ET receptor concentration level was higher in CMS than the healthy controls. Thus, ET-1 may not be a direct etiological variation but may play compensatory roles in CMS patients. The results of the study may provide scientific clues for the prevention and treatment of CMS with higher blood coagulation states of cerebral infarction in patients with chronic high altitude disease. PMID:27485004

  1. Cerebral vasoconstriction reactions and plasma levels of ETBR, ET-1, and eNOS in patients with chronic high altitude disease.

    PubMed

    Wu, Shizheng; Hao, Guisheng; Zhang, Shukun; Jiang, Dongmei; Wuren, Tana; Luo, Junming

    2016-09-01

    The aim of the present study was to examine cerebral vasoconstriction in patients with chronic high altitude disease [cerebrovascular reactivity (CVR)], and to evaluate differences in alterations of brain vascular contractile reactivity of chronic mountain sickness (CMS) patients and healthy controls. Alterations of endothelin (ET) and its receptor, as well as endothelial nitric oxide synthase (eNOS) levels in the plasma were examined to determine the cerebral reservation capacities in CMS patients. Transcranial Doppler ultrasound and carbon dioxide analysis methods were used to detect the CVR variances. At the same time, enzyme‑linked immunosorbent assay approaches were utilized to detect the ET and ET B receptor and the eNOS levels in serum of the CMS patients and healthy controls. CVR and CVRI levels in CMS patients were lower than those of the healthy control subjects and the difference was statistically significant (P<0.05). By contrast, eNOS and ET‑1 levels were not statistically significant for CMS and healthy controls (P>0.05). However, the ET receptor concentration level was higher in CMS than the healthy controls. Thus, ET‑1 may not be a direct etiological variation but may play compensatory roles in CMS patients. The results of the study may provide scientific clues for the prevention and treatment of CMS with higher blood coagulation states of cerebral infarction in patients with chronic high altitude disease. PMID:27485004

  2. Bituminous substances and polycyclic aromatic hydrocarbons in soils under lenses of oil and oil products in underground karst cavities (Polaznenskii Peninsula, Perm region)

    NASA Astrophysics Data System (ADS)

    Pikovskiy, Yu. I.; Smirnova, M. A.; Kovach, R. G.; Puzanova, T. A.; Khlynina, A. V.; Khlynina, N. I.

    2016-03-01

    Bituminous substances and polycyclic aromatic hydrocarbons in soils under karst rocks have been studied for revealing fluxes of oil and oil products in karst cavities near the earth's surface (with the Polaznenskii Peninsula in Perm region as an example). It has been found that the hydrocarbon fluxes from underground oil lenses to the surface can be directly detected from the nonspecific organic components of soils and the composition of free gases circulating in soils. Changes in the soil-geochemical parameters indicative of the presence of an underground oil lens have been revealed. It has been shown that the hydrocarbon fluxes from underground oil lenses to the surface can be mapped from nonspecific organic soil components: composition and amount of bituminous substances, polycyclic aromatic hydrocarbons, and gaseous hydrocarbons.

  3. Prevalence of enteropathogens in stools of rural Maasai children under five years of age in the Maasailand region of the Kenyan Rift Valley.

    PubMed

    Joyce, T; McGuigan, K G; Elmore-Meegan, M; Conroy, R M

    1996-01-01

    Stool samples were collected during August 1994 from seventy rural Maasai children under the age of five years who were living in the Maasailand region of the Kenyan Rift Valley. Microbiological analysis was carried out on these samples to identify which intestinal pathogens were present among the infant population of the Maasai. Of the samples studied 54% were pathogen positive. The most common pathogen isolated was Giardia lamblia which was detected in 31% of the samples. Other pathogens that were detected include: Entamoeba histolytica (23%), Enteropathogenic Escherichia coli (13%), Strongyloides stercoralis (4%), Blastocystis hominis (3%) and Cryptosporidium sp (3%). Although all samples were screened for Campylobacter and rotavirus, neither pathogen was detected. Water samples were taken from all the water sources in the study area and analysed microbiologically. Results showed that all the sources were contaminated with the faecal E. coli whose populations ranged from 14 CFU/100 ml to greater than 1800 CFU/100ml. PMID:8625866

  4. Extinction of the HPV18 upstream regulatory region in cervical carcinoma cells after fusion with non-tumorigenic human keratinocytes under non-selective conditions.

    PubMed Central

    Rösl, F; Achtstätter, T; Bauknecht, T; Hutter, K J; Futterman, G; zur Hausen, H

    1991-01-01

    'Universal fuser' clones of a human papillomavirus type 16 positive cervical carcinoma cell line (SiHa) were established to study the effect of a non-tumorigenic fusion partner on the regulation of a stably integrated chloramphenicol acetyltransferase (CAT) gene controlled by the HPV18 upstream regulatory region under non-selective conditions. The CAT expressing cells were fused with both non-tumorigenic, spontaneously immortalized human keratinocytes (HaCaT) and non-modified SiHa cells. The resulting hybrids were characterized by restriction enzyme fragment length polymorphism analysis and flow cytometry. While the non-selectable, HPV18-driven indicator gene is constitutively expressed in SiHa cells, the CAT activity is extinguished in SiHa x HaCaT cells, but still present in SiHa x SiHa hybrids. Examination of the cytokeratin expression pattern reveals that the keratinocyte phenotype seems not only to be dominant in terms of the extinction of the HPV18 regulatory region but also by the conservation of most of the differentiation markers of the non-tumorigenic fusion partner. Cycloheximide treatment and intracellular competition experiments using the transient COS7 fusion-amplification technique are accompanied by the reactivation of the marker gene in previously CAT- SiHa x HaCaT hybrids. These data strongly suggest that trans-acting negative regulatory factors derived from the non-malignant human keratinocytes are responsible for the extinction phenomenon. Images PMID:1709093

  5. An adaptive approach to invasive plant management on U.S. Fish and Wildlife Service-owned native prairies in the Prairie Pothole Region: decision support under uncertainity

    USGS Publications Warehouse

    Gannon, Jill J.; Moore, Clinton T.; Shaffer, Terry L.; Flanders-Wanner, Bridgette

    2011-01-01

    Much of the native prairie managed by the U.S. Fish and Wildlife Service (Service) in the Prairie Pothole Region (PPR) is extensively invaded by the introduced cool-season grasses smooth brome (Bromus inermis) and Kentucky bluegrass (Poa pratensis). The central challenge to managers is selecting appropriate management actions in the face of biological and environmental uncertainties. We describe the technical components of a USGS management project, and explain how the components integrate and inform each other, how data feedback from individual cooperators serves to reduce uncertainty across the whole region, and how a successful adaptive management project is coordinated and maintained on a large scale. In partnership with the Service, the U.S. Geological Survey is developing an adaptive decision support framework to assist managers in selecting management actions under uncertainty and maximizing learning from management outcomes. The framework is built around practical constraints faced by refuge managers and includes identification of the management objective and strategies, analysis of uncertainty and construction of competing decision models, monitoring, and mechanisms for model feedback and decision selection. Nineteen Service field stations, spanning four states of the PPR, are participating in the project. They share a common management objective, available management strategies, and biological uncertainties. While the scope is broad, the project interfaces with individual land managers who provide refuge-specific information and receive updated decision guidance that incorporates understanding gained from the collective experience of all cooperators.

  6. Infection of Vascular Endothelial Cells with Human Cytomegalovirus under Fluid Shear Stress Reveals Preferential Entry and Spread of Virus in Flow Conditions Simulating Atheroprone Regions of the Artery

    PubMed Central

    DuRose, Jenny B.; Li, Julie; Chien, Shu

    2012-01-01

    Atherosclerosis is a major pathogenic factor in cardiovascular diseases, which are the leading cause of mortality in developed countries. While risk factors for atherosclerosis tend to be systemic, the distribution of atherosclerotic plaques within the vasculature is preferentially located at branch points and curves where blood flow is disturbed and shear stress is low. It is now widely accepted that hemodynamic factors can modulate endothelial gene expression and function and influence the pathophysiological changes associated with atherosclerosis. Human cytomegalovirus (HCMV), a ubiquitous pathogen, has long been proposed as a risk factor for atherosclerosis. To date, the role of HCMV in atherogenesis has been explored only in static conditions, and it is not known how HCMV infection is influenced by the physiological context of flow. In this study, we utilized a parallel-plate flow system to simulate the effects of shear stresses in different regions of the vasculature in vitro. We found that endothelial cells cultured under low shear stress, which simulates the flow condition of atheroprone regions in vivo, are more permissive to HCMV infection than cells experiencing high shear stress or static conditions. Cells exposed to low shear stress show increased entry of HCMV compared to cells exposed to high shear stress or static conditions. Viral structural gene expression, viral titers, and viral spread are also enhanced in endothelial cells exposed to low shear stress. These results suggest that hemodynamic factors modulate HCMV infection of endothelial cells, thus providing new insights into the induction/acceleration of atherosclerosis by HCMV. PMID:23055562

  7. Geoinformational modelling of the land use of Polesye and Opolje landscapes in Bryansk region (Russia) under conditions of 137Cs radionuclides contamination

    NASA Astrophysics Data System (ADS)

    Nenko, Christina; Linnik, Vitaliy; Volkova, Nadezhda

    2015-04-01

    Significant part of Russian Federation was contaminated by 137Cs radionuclides due to Chernobyl disaster in 1986. South-western part of Bryansk region has suffered the most. Study area (the central part of Bryansk region, Polesye and high plains landscapes) is situated outside the officially specified zone of contamination with contamination levels under 1 Ci / km2. Nevertheless, such contamination levels (which are 20 times greater than levels of global fallout) require particular attention as it may contain a threat of the land use and the health of population, living within the territory. Radioactive contamination within the model area was formed as a result of a "dry" deposition from the atmosphere. Consequently, the initial contamination of soil by isotopes 137Cs, unlike the western part of the Bryansk region, was spread relatively equally. The main part of 137Cs (up to 90%) in natural landscapes is contained in the top 5 cm of soil, which itself creates danger of biogeochemical migration from soil to plants. In agricultural landscapes under cultivation 137Cs is uniformly spread within a 20 cm layer of soil and can also come from soil to plants grown in the fields. The area of radioactive contamination that was formed during the period of deposition (late April - early May 1986), is exposed to the processes of secondary redistribution. It is influenced by several factors as topography, vegetation type, proportion of arable soils, soil humidity, soil texture etc. In the presented study there was evaluated the impact of these factors on the secondary redistribution of 137Cs. Sustainable development of agricultural production in the contaminated territories requires managing a number of measures to reduce radiation risks to the population. Regarding this point the greatest threat may be represented by milk production, as well as picking berries and mushrooms. Planning of the sustainable use of the territory requires an evaluation of contamination levels within

  8. Tracing The Origin Of Methane And Water On Mars: Mapping Regions Of Active Release At Ultra-high Spatial Resolution Using Keck And VLT Under AO Control.

    NASA Astrophysics Data System (ADS)

    Mumma, Michael J.; Villanueva, G. L.; Campbell, R.; Lyke, J.; Conrad, A.; Encrenaz, T.; Hartogh, P.; Kauefl, U.; Novak, R. E.; Tokunaga, A.

    2009-09-01

    Strong release of methane from active regions on Mars has been reported in northern summer (1) and southern spring (2). The spatial resolution of these measurements was about 500 km, sufficient to reveal discrete active regions. Regions of methane release appear mainly over ancient terrain (Noachian/Hesperian) known to have a rich hydration history, and often marked by fossae or other scarps. However, higher resolution is needed to test whether methane release is confined to a small number of narrowly defined vents or is widely distributed over the 500 km footprint. If narrowly confined, the plume should have correspondingly higher local density, enhancing spectral searches for water, methane, their isotopologues, and other trace gases that could reveal aspects of methane generation and depth of release. Ground-based telescopes equipped with both adaptive optics (AO) and high dispersion infrared spectrometers have delivered much higher spatial resolution on planetary bodies, but until now have not been applied to Mars. We acquired images and spectra of Mars under AO control at infrared wavelengths, using Keck-2 and ESO-VLT. In June 2009, we acquired test images with NIRC2/Keck-2 using AO in the natural guide star mode and achieved 0.12” FWHM resolution at 3.0 µm wavelength (Mars diameter was 4.7"). Diffraction-limited performance (0.06” at 3 µm) is expected during follow-up observations in September 2009. We observed Mars with UT1 under AO control (MACAO) in August and September 2009, and acquired spectra with CRIRES. We expect to achieve spatial resolution approaching 40 km in November-December 2009, representing a reduction in area by nearly a factor of 100 compared with earlier non-AO searches. Preliminary results will be presented. This work was funded by NASA grants 08-PAST08-0034 (Planetary Astronomy) and 08-PATM080-0031 (Planetary Atmospheres). 1. Mumma, Villanueva, Novak et al., Science 323, 1041 (2009) 2. Villanueva, Mumma, Novak, (in prep) 2009.

  9. A Regional-Scale Evaluation on Environmental Stability Conditions for Convective Rain under Climate Change from Super-High-Resolution GCM Simulations

    NASA Astrophysics Data System (ADS)

    Takemi, T.; Nomura, S.; Oku, Y.; Ishikawa, H.

    2011-12-01

    Understanding and forecasting of convective rain due to intense thunderstorms, which develop under conditions both with and without significant synoptic-scale and/or mesoscale forcings, are critical in dealing with disaster prevention/mitigation and developing urban planning appropriate for disaster management. Thunderstorms rapidly develop even during the daytimes of fair weather conditions without any external forcings, and sometimes become strong enough to induce local-scale meteorological disasters such as torrential rain, flush flooding, high winds, and tornadoes/gusts. With the growing interests in climate change, future changes in the behavior of such convectively generated extreme events have gained scientific and societal interests. This study conducted the regional-scale evaluations on the environmental stability conditions for convective rain that develops under synoptically undisturbed, summertime conditions by using the outputs of super-high-resolution AGCM simulations, at a 20-km resolution, for the present, the near-future, and the future climates under global warming with IPCC A1B emission scenario. The GCM, MRI-AGCM3.2S, was developed by Meteorological Research Institute of Japan Meteorological Agency under the KAKUSHIN program funded by the Ministry of Education, Culture, Sports, Science, and Technology of Japan. The climate simulation outputs that were used in this study corresponded to three 25-year periods: 1980-2004 for the present climate; 2020-2044 for the near-future climate; and 2075-2099 for the future climate. The Kanto Plain that includes the Tokyo metropolitan area was chosen as the study area, since the Tokyo metropolitan area is one of the largest metropolises in the world and is vulnerable to extreme weather events. Therefore, one of the purposes of this study was to examine how regional-scale evaluations are performed from the super-high-resolution GCM outputs. After verifying the usefulness of the GCM present-climate outputs with

  10. Cinnamyl alcohol attenuates vasoconstriction by activation of K+ channels via NO-cGMP-protein kinase G pathway and inhibition of Rho-kinase

    PubMed Central

    Kang, Yun Hwan; Yang, In Jun; Morgan, Kathleen G.

    2012-01-01

    Cinnamyl alcohol (CAL) is known as an antipyretic, and a recent study showed its vasodilatory activity without explaining the mechanism. Here we demonstrate the vasodilatory effect and the mechanism of action of CAL in rat thoracic aorta. The change of tension in aortic strips treated with CAL was measured in an organ bath system. In addition, vascular strips or human umbilical vein endothelial cells (HUVECs) were used for biochemical experiments such as Western blot and nitrite and cyclic guanosine monophosphate (cGMP) measurements. CAL attenuated the vasoconstriction of phenylephrine (PE, 1 µM)-precontracted aortic strips in an endothelium-dependent manner. CAL-induced vasorelaxation was inhibited by pretreatment with NG-nitro-L-arginine methyl ester (L-NAME; 10-4 M), methylene blue (MB; 10-5 M) and 1 H-[1,2,4]-oxadiazolole-[4,3-a] quinoxalin-10one, (ODQ; 10-6 or 10-7 M) in the endothelium-intact aortic strips. Atrial natriuretic peptide (ANP; 10-8 or 10-9 M) did not affect the vasodilatory effect of CAL. The phosphorylation of endothelial nitric oxide synthase (eNOS) and generation of nitric oxide (NO) were stimulated by CAL treatment in HUVECs and inhibited by treatment with L-NAME. In addition, cGMP and PKG1 activation in aortic strips treated with CAL were also significantly inhibited by L-NAME. Furthermore, CAL relaxed Rho-kinase activator calpeptin-precontracted aortic strips, and the vasodilatory effect of CAL was inhibited by the ATP-sensitive K+ channel inhibitor glibenclamide (Gli; 10-5 M) and the voltage-dependent K+ channel inhibitor 4-aminopyridine (4-AP; 2 × 10-4 M). These results suggest that CAL induces vasorelaxation by activating K+ channels via the NO-cGMP-PKG pathway and the inhibition of Rho-kinase. PMID:23178275

  11. Pulmonary Macrophages Attenuate Hypoxic Pulmonary Vasoconstriction via β3AR/iNOS Pathway in Rats Exposed to Chronic Intermittent Hypoxia

    PubMed Central

    Nagai, Hisashi; Kuwahira, Ichiro; Schwenke, Daryl O.; Tsuchimochi, Hirotsugu; Nara, Akina; Ogura, Sayoko; Sonobe, Takashi; Inagaki, Tadakatsu; Fujii, Yutaka; Yamaguchi, Rutsuko; Wingenfeld, Lisa; Umetani, Keiji; Shimosawa, Tatsuo; Yoshida, Ken-ichi; Uemura, Koichi; Pearson, James T.; Shirai, Mikiyasu

    2015-01-01

    Chronic intermittent hypoxia (IH) induces activation of the sympathoadrenal system, which plays a pivotal role in attenuating hypoxic pulmonary vasoconstriction (HPV) via central β1-adrenergic receptors (AR) (brain) and peripheral β2AR (pulmonary arteries). Prolonged hypercatecholemia has been shown to upregulate β3AR. However, the relationship between IH and β3AR in the modification of HPV is unknown. It has been observed that chronic stimulation of β3AR upregulates inducible nitric oxide synthase (iNOS) in cardiomyocytes and that IH exposure causes expression of iNOS in RAW264.7 macrophages. iNOS has been shown to have the ability to dilate pulmonary vessels. Hence, we hypothesized that chronic IH activates β3AR/iNOS signaling in pulmonary macrophages, leading to the promotion of NO secretion and attenuated HPV. Sprague-Dawley rats were exposed to IH (3-min periods of 4–21% O2) for 8 h/d for 6 weeks. The urinary catecholamine concentrations of IH rats were high compared with those of controls, indicating activation of the sympathoadrenal system following chronic IH. Interestingly, chronic IH induced the migration of circulating monocytes into the lungs and the predominant increase in the number of pro-inflammatory pulmonary macrophages. In these macrophages, both β3AR and iNOS were upregulated and stimulation of the β3AR/iNOS pathway in vitro caused them to promote NO secretion. Furthermore, in vivo synchrotron radiation microangiography showed that HPV was significantly attenuated in IH rats and the attenuated HPV was fully restored by blockade of β3AR/iNOS pathway or depletion of pulmonary macrophages. These results suggest that circulating monocyte-derived pulmonary macrophages attenuate HPV via activation of β3AR/iNOS signaling in chronic IH. PMID:26132492

  12. Dipetalodipin, a Novel Multifunctional Salivary Lipocalin That Inhibits Platelet Aggregation, Vasoconstriction, and Angiogenesis through Unique Binding Specificity for TXA2, PGF2α, and 15(S)-HETE*

    PubMed Central

    Assumpção, Teresa C. F.; Alvarenga, Patricia H.; Ribeiro, José M. C.; Andersen, John F.; Francischetti, Ivo M. B.

    2010-01-01

    Dipetalodipin (DPTL) is an 18 kDa protein cloned from salivary glands of the triatomine Dipetalogaster maxima. DPTL belongs to the lipocalin superfamily and has strong sequence similarity to pallidipin, a salivary inhibitor of collagen-induced platelet aggregation. DPTL expressed in Escherichia coli was found to inhibit platelet aggregation by collagen, U-46619, or arachidonic acid without affecting aggregation induced by ADP, convulxin, PMA, and ristocetin. An assay based on incubation of DPTL with small molecules (e.g. prostanoids, leukotrienes, lipids, biogenic amines) followed by chromatography, mass spectrometry, and isothermal titration calorimetry showed that DPTL binds with high affinity to carbocyclic TXA2, TXA2 mimetic (U-46619), TXB2, PGH2 mimetic (U-51605), PGD2, PGJ2, and PGF2α. It also interacts with 15(S)-HETE, being the first lipocalin described to date to bind to a derivative of 15-lipoxygenase. Binding was not observed to other prostaglandins (e.g. PGE1, PGE2, 8-iso-PGF2α, prostacyclin), leukotrienes (e.g,. LTB4, LTC4, LTD4, LTE4), HETEs (e.g. 5(S)-HETE, 12(S)-HETE, 20-HETE), lipids (e.g. arachidonic acid, PAF), and biogenic amines (e.g. ADP, serotonin, epinephrine, norepinephrine, histamine). Consistent with its binding specificity, DPTL prevents contraction of rat uterus stimulated by PGF2α and induces relaxation of aorta previously contracted with U-46619. Moreover, it inhibits angiogenesis mediated by 15(S)-HETE and did not enhance inhibition of collagen-induced platelet aggregation by SQ29548 (TXA2 antagonist) and indomethacin. A 3-D model for DPTL and pallidipin is presented that indicates the presence of a conserved Arg39 and Gln135 in the binding pocket of both lipocalins. Results suggest that DPTL blocks platelet aggregation, vasoconstriction, and angiogenesis through binding to distinct eicosanoids involved in inflammation. PMID:20889972

  13. Fine-Scale Mapping by Spatial Risk Distribution Modeling for Regional Malaria Endemicity and Its Implications under the Low-to-Moderate Transmission Setting in Western Cambodia

    PubMed Central

    Okami, Suguru; Kohtake, Naohiko

    2016-01-01

    The disease burden of malaria has decreased as malaria elimination efforts progress. The mapping approach that uses spatial risk distribution modeling needs some adjustment and reinvestigation in accordance with situational changes. Here we applied a mathematical modeling approach for standardized morbidity ratio (SMR) calculated by annual parasite incidence using routinely aggregated surveillance reports, environmental data such as remote sensing data, and non-environmental anthropogenic data to create fine-scale spatial risk distribution maps of western Cambodia. Furthermore, we incorporated a combination of containment status indicators into the model to demonstrate spatial heterogeneities of the relationship between containment status and risks. The explanatory model was fitted to estimate the SMR of each area (adjusted Pearson correlation coefficient R2 = 0.774; Akaike information criterion AIC = 149.423). A Bayesian modeling framework was applied to estimate the uncertainty of the model and cross-scale predictions. Fine-scale maps were created by the spatial interpolation of estimated SMRs at each village. Compared with geocoded case data, corresponding predicted values showed conformity [Spearman’s rank correlation r = 0.662 in the inverse distance weighed interpolation and 0.645 in ordinal kriging (95% confidence intervals of 0.414–0.827 and 0.368–0.813, respectively), Welch’s t-test; Not significant]. The proposed approach successfully explained regional malaria risks and fine-scale risk maps were created under low-to-moderate malaria transmission settings where reinvestigations of existing risk modeling approaches were needed. Moreover, different representations of simulated outcomes of containment status indicators for respective areas provided useful insights for tailored interventional planning, considering regional malaria endemicity. PMID:27415623

  14. Abundant local interactions in the 4p16.1 region suggest functional mechanisms underlying SLC2A9 associations with human serum uric acid.

    PubMed

    Wei, Wen-Hua; Guo, Yunfei; Kindt, Alida S D; Merriman, Tony R; Semple, Colin A; Wang, Kai; Haley, Chris S

    2014-10-01

    Human serum uric acid concentration (SUA) is a complex trait. A recent meta-analysis of multiple genome-wide association studies (GWAS) identified 28 loci associated with SUA jointly explaining only 7.7% of the SUA variance, with 3.4% explained by two major loci (SLC2A9 and ABCG2). Here we examined whether gene-gene interactions had any roles in regulating SUA using two large GWAS cohorts included in the meta-analysis [the Atherosclerosis Risk in Communities study cohort (ARIC) and the Framingham Heart Study cohort (FHS)]. We found abundant genome-wide significant local interactions in ARIC in the 4p16.1 region located mostly in an intergenic area near SLC2A9 that were not driven by linkage disequilibrium and were replicated in FHS. Taking the forward selection approach, we constructed a model of five SNPs with marginal effects and three epistatic SNP pairs in ARIC-three marginal SNPs were located within SLC2A9 and the remaining SNPs were all located in the nearby intergenic area. The full model explained 1.5% more SUA variance than that explained by the lead SNP alone, but only 0.3% was contributed by the marginal and epistatic effects of the SNPs in the intergenic area. Functional analysis revealed strong evidence that the epistatically interacting SNPs in the intergenic area were unusually enriched at enhancers active in ENCODE hepatic (HepG2, P = 4.7E-05) and precursor red blood (K562, P = 5.0E-06) cells, putatively regulating transcription of WDR1 and SLC2A9. These results suggest that exploring epistatic interactions is valuable in uncovering the complex functional mechanisms underlying the 4p16.1 region. PMID:24821702

  15. Effects of Revegetation on Soil Organic Carbon Storage and Erosion-Induced Carbon Loss under Extreme Rainstorms in the Hill and Gully Region of the Loess Plateau

    PubMed Central

    Li, Yujin; Jiao, Juying; Wang, Zhijie; Cao, Binting; Wei, Yanhong; Hu, Shu

    2016-01-01

    Background: The Loess Plateau, an ecologically vulnerable region, has long been suffering from serious soil erosion. Revegetation has been implemented to control soil erosion and improve ecosystems in the Loess Plateau region through a series of ecological recovery programs. However, the increasing atmospheric CO2 as a result of human intervention is affecting the climate by global warming, resulting in the greater frequency and intensity of extreme weather events, such as storms that may weaken the effectiveness of revegetation and cause severe soil erosion. Most research to date has evaluated the effectiveness of revegetation on soil properties and soil erosion of different land use or vegetation types. Here, we study the effect of revegetation on soil organic carbon (SOC) storage and erosion-induced carbon loss related to different plant communities, particularly under extreme rainstorm events. Materials and methods: The erosion-pin method was used to quantify soil erosion, and soil samples were taken at soil depths of 0–5 cm, 5–10 cm and 10–20 cm to determine the SOC content for 13 typical hillside revegetation communities in the year of 2013, which had the highest rainfall with broad range, long duration and high intensity since 1945, in the Yanhe watershed. Results and discussion: The SOC concentrations of all plant communities increased with soil depth when compared with slope cropland, and significant increases (p < 0.05) were observed for most shrub and forest communities, particularly for natural ones. Taking the natural secondary forest community as reference (i.e., soil loss and SOC loss were both 1.0), the relative soil loss and SOC loss of the other 12 plant communities in 2013 ranged from 1.5 to 9.4 and 0.30 to 1.73, respectively. Natural shrub and forest communities showed greater resistance to rainstorm erosion than grassland communities. The natural grassland communities with lower SOC content produced lower SOC loss even with higher soil

  16. SU-F-BRD-16: Under Dose Regions Recalculated by Monte Carlo Cannot Predict the Local Failure for NSCLC Patients Treated with SBRT

    SciTech Connect

    Liu, H; Cherian, S; Stephans, K; Videtic, G; Qi, P; Xia, P; Zhuang, T

    2014-06-15

    Purpose: To investigate whether Monte Carlo (MC) recalculated dose distributions can predict the geometric location of the recurrence for nonsmall cell lung cancer (NSCLC) patients treated with stereotactic body radiotherapy (SBRT). Methods: Thirty NSCLC patients with local recurrence were retrospectively selected for this study. The recurred gross target volumes (rGTV) were delineated on the follow-up CT/PET images and then rigidly transferred via imaging fusion to the original planning CTs. Failure pattern was defined according to the overlap between the rGTV and planning GTV (pGTV) as: (a) in-field failure (≥80%), (b) marginal failure (20%–80%), and (c) out-of-field failure (≤20%). All clinical plans were calculated initially with pencil beam (PB) with or without heterogeneity correction dependent of protocols. These plans were recalculated with MC with heterogeneity correction. Because of non-uniform dose distributions in the rGTVs, the rGTVs were further divided into four regions: inside the pGTV (GTVin), inside the PTV (PTVin), outside the pGTV (GTVout), and outside the PTV (PTVout). The mean doses to these regions were reported and analyzed separately. Results: Among 30 patients, 10 patients had infield recurrences, 15 marginal and 5 out-of-field failures. With MC calculations, D95 and D99 of the PTV were reduced by (10.6 ± 7.4)% and (11.7 ± 7.9)%. The average MC calculated mean doses of GTVin, GTVout, PTVin and PTVout were 48.2 ± 5.3 Gy, 48.2 ± 5.5 Gy, 46.3 ± 6.2 Gy and 46.6 ± 5.6 Gy, respectively. No significant dose differences between GTVin and GTVout (p=0.65), PTVin and PTVout (p=0.19) were observed, using the paired students t-test. Conclusion: Although the PB calculations underestimated the tumor target doses, the geometric location of the recurrence did not correlate with the mean doses of subsections of the recurrent GTV. Under dose regions recalculated by MC cannot predict the local failure for NSCLC patients treated with SBRT.

  17. A critical assessment of oral care protocols for patients under radiation therapy in the regional University Hospital Network of Madrid (Spain)

    PubMed Central

    Lanzós, Isabel; Lanzós, Eduardo; Sanz, Mariano

    2015-01-01

    Background This research was aimed to critically evaluate, under the light of the available scientific evidence, the oral care protocols recommended by different hospitals in head and neck cancer (HNC) patients under radiation therapy. Material and Methods A questionnaire requesting all the relevant information for the oral care of these patients was sent to the 9 University Hospitals in Madrid. The answers were categorized and analyzed. In addition, an electronic search was conducted to identify the most relevant papers (systematic reviews [SR] and randomized clinical trials [RCTs]) assessing oral care protocols for patients treated for HNC with radiation therapy. Results Eight out of nine centers answered the questionnaire and the retrieved information was tabulated and compared. These recommendations were analyzed by a computerized search on MEDLINE and the Cochrane Oral Health Collaboration Database. The results of the analysis clearly shown a great heterogeneity, in terms of oral health care protocols, regarding the management of irradiated patients (for HNC) within the Hospitals of Madrid region. In addition, some of the recommendations lack solid scientific support. Conclusions The present survey revealed that the recommendations provided by the different hospitals were clearly different. The available evidence, supported by SR and RCTs, suggested the need of an oral assessment before cancer treatment, in order to prevent and treat dental pathologies and avoiding potential complications; during cancer treatment, it is relevant monitoring the patient in order to decrease the severity of the side effects, and to avoid any tooth extraction or surgery and special attention should be paid to mucositis, xerostomia and candidiasis; after cancer treatment, the following are relevant aspects: the risk of osteoradionecrosis, trismus, caries and the risks associated to dental implants. Key words:Head and neck cancer, supportive care in cancer, radiotherapy

  18. Segregation of anterior temporal regions critical for retrieving names of unique and non-unique entities reflects underlying long-range connectivity.

    PubMed

    Mehta, Sonya; Inoue, Kayo; Rudrauf, David; Damasio, Hanna; Tranel, Daniel; Grabowski, Thomas

    2016-02-01

    Lesion-deficit studies support the hypothesis that the left anterior temporal lobe (ATL) plays a critical role in retrieving names of concrete entities. They further suggest that different regions of the left ATL process different conceptual categories. Here we test the specificity of these relationships and whether the anatomical segregation is related to the underlying organization of white matter connections. We reanalyzed data from a previous lesion study of naming and recognition across five categories of concrete entities. In voxelwise logistic regressions of lesion-deficit associations, we formally incorporated measures of disconnection of long-range association fiber tracts (FTs) and covaried for recognition and non-category-specific naming deficits. We also performed fiber tractwise analyses to assess whether damage to specific FTs was preferentially associated with category-selective naming deficits. Damage to the basolateral ATL was associated with naming deficits for both unique (famous faces) and non-unique entities, whereas the damage to the temporal pole was associated with naming deficits for unique entities only. This segregation pattern remained after accounting for comorbid recognition deficits or naming deficits in other categories. The tractwise analyses showed that damage to the uncinate fasciculus (UNC) was associated with naming impairments for unique entities, while damage to the inferior longitudinal fasciculus (ILF) was associated with naming impairments for non-unique entities. Covarying for FT transection in voxelwise analyses rendered the cortical association for unique entities more focal. These results are consistent with the partial segregation of brain system support for name retrieval of unique and non-unique entities at both the level of cortical components and underlying white matter fiber bundles. Our study reconciles theoretic accounts of the functional organization of the left ATL by revealing both category-related processing

  19. Diffusion of hydrogen interstitials in the near-surface region of Pd(111) under the influence of surface coverage and external static electric fields

    NASA Astrophysics Data System (ADS)

    Blanco-Rey, M.; Tremblay, J. C.

    2015-04-01

    Past scanning tunneling microscopy (STM) experiments of H manipulation on Pd(111), at low temperature, have shown that it is possible to induce diffusion of surface species as well as of those deeply buried under the surface. Several questions remain open regarding the role of subsurface site occupancies. In the present work, the interaction potential of H atoms with Pd(111) under various H coverage conditions is determined by means of density functional theory calculations in order to provide an answer to two of these questions: (i) whether subsurface sites are the final locations for the H impurities that attempt to emerge from bulk regions, and (ii) whether penetration of the surface is a competing route of on-surface diffusion during depletion of surface H on densely covered Pd(111). We find that a high H coverage has the effect of blocking resurfacing of H atoms travelling from below, which would otherwise reach the surface fcc sites, but it hardly alters deeper diffusion energy barriers. Penetration is unlikely and restricted to high occupancies of hcp hollows. In agreement with experiments, the Pd lattice expands vertically as a consequence of H atoms being blocked at subsurface sites, and surface H enhances this expansion. STM tip effects are included in the calculations self-consistently as an external static electric field. The main contribution to the induced surface electric dipoles originates from the Pd substrate polarisability. We find that the electric field has a non-negligible effect on the H-Pd potential in the vicinity of the topmost Pd atomic layer, yet typical STM intensities of 1-2 VÅ-1 are insufficient to invert the stabilities of the surface and subsurface equilibrium sites.

  20. Diffusion of hydrogen interstitials in the near-surface region of Pd(111) under the influence of surface coverage and external static electric fields

    SciTech Connect

    Blanco-Rey, M.; Tremblay, J. C.

    2015-04-21

    Past scanning tunneling microscopy (STM) experiments of H manipulation on Pd(111), at low temperature, have shown that it is possible to induce diffusion of surface species as well as of those deeply buried under the surface. Several questions remain open regarding the role of subsurface site occupancies. In the present work, the interaction potential of H atoms with Pd(111) under various H coverage conditions is determined by means of density functional theory calculations in order to provide an answer to two of these questions: (i) whether subsurface sites are the final locations for the H impurities that attempt to emerge from bulk regions, and (ii) whether penetration of the surface is a competing route of on-surface diffusion during depletion of surface H on densely covered Pd(111). We find that a high H coverage has the effect of blocking resurfacing of H atoms travelling from below, which would otherwise reach the surface fcc sites, but it hardly alters deeper diffusion energy barriers. Penetration is unlikely and restricted to high occupancies of hcp hollows. In agreement with experiments, the Pd lattice expands vertically as a consequence of H atoms being blocked at subsurface sites, and surface H enhances this expansion. STM tip effects are included in the calculations self-consistently as an external static electric field. The main contribution to the induced surface electric dipoles originates from the Pd substrate polarisability. We find that the electric field has a non-negligible effect on the H-Pd potential in the vicinity of the topmost Pd atomic layer, yet typical STM intensities of 1-2 VÅ{sup −1} are insufficient to invert the stabilities of the surface and subsurface equilibrium sites.

  1. GOCE observations and geophysical constraints to better understand the lithosphere and geodynamical processes under the Paraná-Etendeka region: preliminary results of PERLA project

    NASA Astrophysics Data System (ADS)

    Mariani, Patrizia; Braitenberg, Carla

    2014-05-01

    In the light of the considerable progress made by the modern geodetic satellite mission GOCE, one of the challenges of the European Space Agency (ESA) is to improve knowledge of physical properties and geodynamic processes of the lithosphere and the Earth deep interior, and their relationship to Earth-surface changes. In this context we propose a study that aims to understand the two pieces of lithosphere underlying the Paraná-Etendeka conjugate margins (Brazil, and Angola-Namibia). It is essential to collect the geological and geophysical information about the thickness and the density of sedimentary layers, crustal thickness and mantle inhomogeneities. Our methodology integrates the geophysical database with the GOCE data, product of the innovative gravity satellite mission, that was concluded November 2013. Crustal thickness was obtained from all available seismological datasets. The density-depth relation of the shallow layers is modeled by geophysical data collected from literature and from the on-shore and off-shore drilling programs. Several compaction laws are used to estimate the density of each layer. This information is necessary to reduce the observations considering the gravity effect of all intracrustal known layers, to resolve the deep crustal structures (e.g. Moho and intracrustal bodies). A positive gravity anomaly is expected due to the magmatic activity of the Paraná-Etendeka province. The smaller-scale and shallow gravity anomaly should be due to the occurrence of the volcanic activity close to the alkaline-carbonatite complexes, while the large-scale anomaly is expected from the underplating of a wide denser body at the depth of the crustal mantle boundary. In the present work some preliminary results of the inversion of the residual gravity anomaly in terms of densities in the middle and shallow lithosphere under the Paraná-Etendeka region will be presented and interpreted.

  2. Identification of Extreme Events Under Climate Change Conditions Over Europe and The Northwest-atlantic Region: Spatial Patterns and Time Series Characteristics

    NASA Astrophysics Data System (ADS)

    Leckebusch, G.; Ulbrich, U.; Speth, P.

    In the context of climate change and the resulting possible impacts on socio-economic conditions for human activities it seems that due to a changed occurrence of extreme events more severe consequences have to be expected than from changes in the mean climate. These extreme events like floods, excessive heats and droughts or windstorms possess impacts on human social and economic life in different categories such as forestry, agriculture, energy use, tourism and the reinsurance business. Reinsurances are affected by nearly 70% of all insured damages over Europe in the case of wind- storms. Especially the December 1999 French windstorms caused damages about 10 billion. A new EU-founded project (MICE = Modelling the Impact of Climate Ex- tremes) will focus on these impacts caused by changed occurrences of extreme events over Europe. Based upon the output of general circulation models as well as regional climate models, investigations are carried out with regard to time series characteristics as well as the spatial patterns of extremes under climate changed conditions. After the definition of specific thresholds for climate extremes, in this talk we will focus on the results of the analysis for the different data sets (HadCM3 and CGCMII GCM's and RCM's, re-analyses, observations) with regard to windstorm events. At first the results of model outputs are validated against re-analyses and observations. Especially a comparison of the stormtrack (2.5 to 8 day bandpass filtered 500 hPa geopotential height), cyclone track, cyclone frequency and intensity is presented. Highly relevant to damages is the extreme wind near the ground level, so the 10 m wind speed will be investigated additionally. of special interest to possible impacts is the changed spatial occurrence of windspeed maxima under 2xCO2-induced climate change.

  3. Impact of climate change on soil thermal and moisture regimes in Serbia: An analysis with data from regional climate simulations under SRES-A1B.

    PubMed

    Mihailović, D T; Drešković, N; Arsenić, I; Ćirić, V; Djurdjević, V; Mimić, G; Pap, I; Balaž, I

    2016-11-15

    We considered temporal and spatial variations to the thermal and moisture regimes of the most common RSGs (Reference Soil Groups) in Serbia under the A1B scenario for the 2021-2050 and 2071-2100 periods, with respect to the 1961-1990 period. We utilized dynamically downscaled global climate simulations from the ECHAM5 model using the coupled regional climate model EBU-POM (Eta Belgrade University-Princeton Ocean Model). We analysed the soil temperature and moisture time series using simple statistics and a Kolmogorov complexity (KC) analysis. The corresponding metrics were calculated for 150 sites. In the future, warmer and drier regimes can be expected for all RSGs in Serbia. The calculated soil temperature and moisture variations include increases in the mean annual soil temperature (up to 3.8°C) and decreases in the mean annual soil moisture (up to 11.3%). Based on the KC values, the soils in Serbia are classified with respect to climate change impacts as (1) less sensitive (Vertisols, Umbrisols and Dystric Cambisols) or (2) more sensitive (Chernozems, Eutric Cambisols and Planosols). PMID:27473773

  4. The microbial biomass in paleosols buried under kurgans and in recent soils in the steppe zone of the Lower Volga region

    NASA Astrophysics Data System (ADS)

    Kashirskaya, N. N.; Khomutova, T. E.; Demkina, T. S.; Demkin, V. A.

    2009-05-01

    The total microbial biomass (TMB) was assessed in the chestnut and light chestnut soils and in the paleosols under burial mounds (steppe kurgans) in the Lower Volga region on the basis of data on the organic carbon content in the extracted microbial fraction supplemented with the data on the extraction completeness as a conversion coefficient. The completeness of the microbial fraction extraction was determined by direct counting of the microbial cells and colony-forming units (on plates with soil agar). The total microbial biomass varied from 400 to 6600 μg of C/soil. Its values in the buried soils were 3-5 times lower than those in the surface soils. The TMB distribution in the buried chestnut soil profile was close to that in its modern analogue (with the minimum in the B1 horizon). In the buried light chestnut paleosols, the TMB values usually increased down the profile; in the recent light chestnut soils, the maximum TMB values were found in the uppermost horizon.

  5. Air quality co-benefits and costs under state, regional, or national cooperation to regulate CO2 from existing power plants

    NASA Astrophysics Data System (ADS)

    Saari, R.; Selin, N. E.

    2015-12-01

    We examine the effect of state, regional, and national cooperation on the costs and air quality co-benefits of a policy to limit the carbon intensity of existing electricity generation. Electricity generation is a significant source of both greenhouse gases and air pollutant emissions that harm human health. Previous studies have shown that air quality co-benefits can be substantial compared to the costs of limiting carbon emissions in the energy system. The EPA's proposed Clean Power Plan seeks to impose carbon intensity limits for each state, but allows states to cooperate in order to meet combined limits. We explore how such cooperation might produce trade-offs between lower costs, widespread pollution reductions, and local reductions. We employ a new state-level model of the US energy system and economy to examine the costs and emissions as states reduce demand or deploy cleaner generation. We use an advanced air quality impacts modeling system, including SMOKE, CAMx, and BenMAP, to estimate health-related air quality co-benefits and compare these to costs under different levels of cooperation. We draw conclusions about the potential impacts of cooperation on economic welfare at various scales.

  6. Regions of the bread wheat D genome associated with variation in key photosynthesis traits and shoot biomass under both well watered and water deficient conditions.

    PubMed

    Osipova, Svetlana; Permyakov, Alexey; Permyakova, Marina; Pshenichnikova, Tatyana; Verkhoturov, Vasiliy; Rudikovsky, Alexandr; Rudikovskaya, Elena; Shishparenok, Alexandr; Doroshkov, Alexey; Börner, Andreas

    2016-05-01

    A quantitative trait locus (QTL) approach was taken to reveal the genetic basis in wheat of traits associated with photosynthesis during a period of exposure to water deficit stress. The performance, with respect to shoot biomass, gas exchange and chlorophyll fluorescence, leaf pigment content and the activity of various ascorbate-glutathione cycle enzymes and catalase, of a set of 80 wheat lines, each containing a single chromosomal segment introgressed from the bread wheat D genome progenitor Aegilops tauschii, was monitored in plants exposed to various water regimes. Four of the seven D genome chromosomes (1D, 2D, 5D, and 7D) carried clusters of both major (LOD >3.0) and minor (LOD between 2.0 and 3.0) QTL. A major QTL underlying the activity of glutathione reductase was located on chromosome 2D, and another, controlling the activity of ascorbate peroxidase, on chromosome 7D. A region of chromosome 2D defined by the microsatellite locus Xgwm539 and a second on chromosome 7D flanked by the marker loci Xgwm1242 and Xgwm44 harbored a number of QTL associated with the water deficit stress response. PMID:26374127

  7. Determination of complex optical indices in the 80-140nm VUV wavelength region from reflectivity measurements under normal incidence: application to ZnSe

    NASA Astrophysics Data System (ADS)

    Bridou, F.; Cuniot-Ponsard, M.; Desvignes, J. M.

    2005-09-01

    The observation of hot plasmas in the interstellar medium requires efficient mirrors in the 80-120 nm wavelength range. Contrary to that of most metals, the high reflectivity of pure aluminum is maintained close to 80% in this range. Unfortunately, it is drastically reduced to values lower than 10% by the strongly absorbing thin alumina layer which spontaneously forms upon air contact. We report here the results obtained with a capper layer of ZnSe. The optical indices given for this material by Palik's tables lead to predict a resulting high reflectivity, provided the layer prevents oxidization of underlying Al. The measured reflectivity does not agree with theory. The reasons for this inconsistency are examined. It is shown that complex indices of ZnSe in the wavelength region between 80 and 140 nm can be extracted. from the reflectivity measurements obtained with different ZnSe thicknesses on Al. The imaginary part of the index is then found to differ strongly from Palik's tables value.

  8. Control of experimental Triatoma infestans populations: effect of pour-on cypermethrin applied to chickens under natural conditions in the Argentinean Chaco region.

    PubMed

    Amelotti, I; Catalá, S S; Gorla, D E

    2014-06-01

    Among peridomestic structures, chicken coops are sites of major importance for the domestic ecology of Triatoma infestans (Hemiptera: Reduviidae). The aim of this study was to evaluate in an experimental context the effects of a cypermethrin pour-on formulation applied to chickens on blood intake, moulting and mortality in T. infestans, under the natural climatic conditions of a region endemic for Chagas' disease. Experimental chicken huts were made of bricks and covered with plastic mosquito nets. Ninety fourth-instar nymphs were maintained in each hut. The study used a completely random design in which chickens in the experimental group were treated with a cypermethrin pour-on formulation. Five replicates (= huts) of the experimental and control groups were conducted. The number of live T. infestans, blood intake and moults to fifth-instar stage were recorded at 1, 5, 20, 35 and 45 days after the application of cypermethrin. Cumulative mortality was higher in nymphs exposed to treated chickens (> 71%) than in control nymphs (< 50%) (P < 0.01). Blood intake and moulting rate were lower in nymphs fed on treated chickens than in control nymphs (P < 0.05). Pour-on cypermethrin was able to cause significant mortality, although it did not eliminate the experimental population of T. infestans. PMID:24191962

  9. Development of ground vegetation under exotic tree plantations on restored coal mine spoil land in a dry tropical region of India.

    PubMed

    Dutta, Raman Kumar; Agrawal, Madhoolika

    2005-10-01

    Restoration of mine spoil is a prime need for coal industry. The study of ground cover vegetation provides essential information about the species diversity and their successional trends during the restoration. The present study was conducted to analyze the structure and biomass accumulation of ground vegetation developing in different plantation stands of an opencast coal mine spoil in a dry tropical region. Different plantation stands showed variations in species diversities. Exotic herbs were more dominant in comparison to native herbs. Pennisetum pedicillatum, an exotic herb showed maximum Importance Value Index in most of the plantation stands. Total number of species varied between 12-18 in different plantation stands. Speces richness and evenness increased with increasing age of the plantations. Variations in total biomass accumulation of ground vegetation were also significant among different plantations. These results suggest that reforestation programme with exotic species on coal mine spoil has been successful in colonization of ground vegetation under different plantations. Gravellia pteridifolia plantations showed most successful ground cover among different plantation stands. PMID:16459550

  10. Regional evaluation of the hydrogeologic framework, hydraulic properties, and chemical characteristics of the intermediate aquifer system underlying southern west-central Florida

    USGS Publications Warehouse

    Knochenmus, Lari A.

    2006-01-01

    underlying Upper Floridan aquifer. In parts of the study area, particularly in southwestern Hillsborough County and southeastern De Soto and Charlotte Counties, Zone 3 likely is contiguous with and part of the Upper Floridan aquifer. Transmissivity of the intermediate aquifer system ranges over five orders of magnitude from about 1 to more than 40,000 feet squared per day (ft2/d), but rarely exceeds 10,000 ft2/d. The overall transmissivity of the intermediate aquifer system is substantially lower (2 to 3 orders of magnitude) than the underlying Upper Floridan aquifer. Transmissivity varies vertically among the zones within the intermediate aquifer system; Zone 2 has the lowest median transmissivity (700 ft2/d), Zone 1 has a moderate median transmissivity (2,250 ft2/d), and Zone 3 has the highest median transmissivity (3,400 ft2/d). Additionally, the transmissivity varies geographically (from site to site) within a zone. Specifically, a region of relatively low transmissivity (<100 ft2/d) throughout the vertical extent of the intermediate aquifer system is present in the central part of the study area. This low transmissivity region is encompassed by a larger region of moderately low transmissivity (<1,000 ft2/d) that covers a large part of the study area. Clay beds and fine-grained carbonates form the confining units between the water-bearing zones and are characterized by low leakance. Leakance through the intermediate aquifer system confining units ranges over 4 orders of magnitude from 4.2x10-7 to 6.0x10-3 feet per day per foot [(ft/d)/ft]. Despite the large range, the geometric mean and median leakances of individual confining units are within the same order of magnitude, 10-5 (ft/d)/ft, which is 2 orders of magnitude less than the median leakance of the semiconfining unit within the Upper Floridan aquifer. Major ion concentrations in water from the intermediate aquifer system, and throughout the ground-water flow system, generally increase with depth. T

  11. A 4-year sediment trap record of alkenones from the filamentous upwelling region off Cape Blanc, NW Africa and a comparison with distributions in underlying sediments

    NASA Astrophysics Data System (ADS)

    Müller, Peter J.; Fischer, Gerhard

    2001-08-01

    We analysed long-chain alkenones in sinking particles and surface sediments from the filamentous upwelling region off Cape Blanc, NW Africa, to evaluate the transfer of surface water signals into the geological record. Our study is based on time-series sediment trap records from 730 m (1990-1991) to 2195-3562 m depth (1988-1991). Alkenone fluxes showed considerable interannual variations and no consistent seasonality. The average flux of C 37 and C 38 alkenones to the deep traps was 1.9 μg m -2 d -1 from March 1988 to October 1990 and sevenfold higher in the subsequent year. Alkenone fluxes to the shallower traps were on average twice as high and showed similar temporal variations. The alkenone unsaturation indices UK' 37, UK38Me and UK38Et closely mirrored the seasonal variations in sea-surface temperature (weekly Reynolds SST). Time lags of 10-48 days between the SST and unsaturation maxima suggest particle sinking rates of about 80 and 280 m d -1 for the periods of low and high alkenone fluxes, respectively. The average flux-weighted UK' 37 temperature for the 4-year time series of the deeper traps was 22.1°C, in perfect agreement with the mean weekly SST for the same period. This and the comparison with seasonal temperature variations in the upper 100 m of the water column suggests that UK' 37 records principally the yearly average of the mixed-layer temperature in this region. A comparison between the average annual alkenone fluxes to the lower traps (2400 μg m -2 yr -1) and into the underlying sediments (4 μg m -2 yr -1) suggests that only about 0.2% of the alkenones reaching the deep ocean became preserved in the sediments. The flux-weighted alkenone concentrations also decreased considerably, from 2466 μg gC -1 in the water column to 62 μg gC -1 in the surface sediments. Such a low degree of alkenone preservation is typical for slowly accumulating oxygenated sediments. Despite these dramatic diagenetic alkenone losses, the UK' 37 ratio was not

  12. β2-Adrenergic Receptor-Dependent Attenuation of Hypoxic Pulmonary Vasoconstriction Prevents Progression of Pulmonary Arterial Hypertension in Intermittent Hypoxic Rats

    PubMed Central

    Nagai, Hisashi; Kuwahira, Ichiro; Schwenke, Daryl O.; Tsuchimochi, Hirotsugu; Nara, Akina; Inagaki, Tadakatsu; Ogura, Sayoko; Fujii, Yutaka; Umetani, Keiji; Shimosawa, Tatsuo; Yoshida, Ken-ichi; Pearson, James T.; Uemura, Koichi; Shirai, Mikiyasu

    2014-01-01

    In sleep apnea syndrome (SAS), intermittent hypoxia (IH) induces repeated episodes of hypoxic pulmonary vasoconstriction (HPV) during sleep, which presumably contribute to pulmonary arterial hypertension (PAH). However, the prevalence of PAH was low and severity is mostly mild in SAS patients, and mild or no right ventricular hypertrophy (RVH) was reported in IH-exposed animals. The question then arises as to why PAH is not a universal finding in SAS if repeated hypoxia of sufficient duration causes cycling HPV. In the present study, rats underwent IH at a rate of 3 min cycles of 4–21% O2 for 8 h/d for 6w. Assessment of diameter changes in small pulmonary arteries in response to acute hypoxia and drugs were performed using synchrotron radiation microangiography on anesthetized rats. In IH-rats, neither PAH nor RVH was observed and HPV was strongly reversed. Nadolol (a hydrophilic β1, 2-blocker) augmented the attenuated HPV to almost the same level as that in N-rats, but atenolol (a hydrophilic β1-blocker) had no effect on the HPV in IH. These β-blockers had almost no effect on the HPV in N-rats. Chronic administration of nadolol during 6 weeks of IH exposure induced PAH and RVH in IH-rats, but did not in N-rats. Meanwhile, atenolol had no effect on morphometric and hemodynamic changes in N and IH-rats. Protein expression of the β1-adrenergic receptor (AR) was down-regulated while that of β2AR was preserved in pulmonary arteries of IH-rats. Phosphorylation of p85 (chief component of phosphoinositide 3-kinase (PI3K)), protein kinase B (Akt), and endothelial nitric oxide synthase (eNOS) were abrogated by chronic administration of nadolol in the lung tissue of IH-rats. We conclude that IH-derived activation of β2AR in the pulmonary arteries attenuates the HPV, thereby preventing progression of IH-induced PAH. This protective effect may depend on the β2AR-Gi mediated PI3K/Akt/eNOS signaling pathway. PMID:25350545

  13. Involvement of gap junctions between smooth muscle cells in sustained hypoxic pulmonary vasoconstriction development: a potential role for 15-HETE and 20-HETE.

    PubMed

    Kizub, Igor V; Lakhkar, Anand; Dhagia, Vidhi; Joshi, Sachindra R; Jiang, Houli; Wolin, Michael S; Falck, John R; Koduru, Sreenivasulu Reddy; Errabelli, Ramu; Jacobs, Elizabeth R; Schwartzman, Michal L; Gupte, Sachin A

    2016-04-15

    In response to hypoxia, the pulmonary artery normally constricts to maintain optimal ventilation-perfusion matching in the lung, but chronic hypoxia leads to the development of pulmonary hypertension. The mechanisms of sustained hypoxic pulmonary vasoconstriction (HPV) remain unclear. The aim of this study was to determine the role of gap junctions (GJs) between smooth muscle cells (SMCs) in the sustained HPV development and involvement of arachidonic acid (AA) metabolites in GJ-mediated signaling. Vascular tone was measured in bovine intrapulmonary arteries (BIPAs) using isometric force measurement technique. Expression of contractile proteins was determined by Western blot. AA metabolites in the bath fluid were analyzed by mass spectrometry. Prolonged hypoxia elicited endothelium-independent sustained HPV in BIPAs. Inhibition of GJs by 18β-glycyrrhetinic acid (18β-GA) and heptanol, nonspecific blockers, and Gap-27, a specific blocker, decreased HPV in deendothelized BIPAs. The sustained HPV was not dependent on Ca(2+) entry but decreased by removal of Ca(2+) and by Rho-kinase inhibition with Y-27632. Furthermore, inhibition of GJs decreased smooth muscle myosin heavy chain (SM-MHC) expression and myosin light chain phosphorylation in BIPAs. Interestingly, inhibition of 15- and 20-hydroxyeicosatetraenoic acid (HETE) synthesis decreased HPV in deendothelized BIPAs. 15-HETE- and 20-HETE-stimulated constriction of BIPAs was inhibited by 18β-GA and Gap-27. Application of 15-HETE and 20-HETE to BIPAs increased SM-MHC expression, which was also suppressed by 18β-GA and by inhibitors of lipoxygenase and cytochrome P450 monooxygenases. More interestingly, 15,20-dihydroxyeicosatetraenoic acid and 20-OH-prostaglandin E2, novel derivatives of 20-HETE, were detected in tissue bath fluid and synthesis of these derivatives was almost completely abolished by 18β-GA. Taken together, our novel findings show that GJs between SMCs are involved in the sustained HPV in BIPAs, and

  14. Using stable water isotopes to delineate dominant flow path along hillslopes under varying land uses in a tropical mountain region of South Ecuador

    NASA Astrophysics Data System (ADS)

    Windhorst, David; Timbe, Edison; Kraft, Philipp; Frede, Hans-Georg; Breuer, Lutz

    2013-04-01

    Knowing the dominant flow paths within a hydrological system is challenging and crucial to assess the relevant discharge generating processes and the fate of water and solutes in the system. However especially the interpretation of those path ways seems controversy within our study area of the Rio San Francisco in the outskirts of the Amazon basin in a tropical mountainous region of South Ecuador. E.g. the recorded flashiness of the hydrograph contravenes the long mean residence time and hydrogeochemical signature of the event water marking it as old water. Even though theories exist which could reveal these contradictions (e.g. the concept of transmissivity feedback which could be used to explain the rapid mobilization of old water) proof is currently missing to support those concepts. To further study the fate of the water and water pound solutes we installed along two hillslopes (length about 500m each and decline 230m under forest and 157m under pasture) three wick samplers collecting weekly bulk samples of soil water in 10, 25, 40 cm depths for 2 years. The isotopic signature (δ18O and δ2H) of the soil water as well as the incoming rainfall was analyzed using an isotope laser spectrometer (Picarro). We propose the usage of stable water isotopes as conservative tracers to validate a 2D setup of the Catchment Modeling Framework (CMF) simulating the water flow and fate of solutes along the hillslopes. The usage of conservative tracers, such as δ18O and δ2H, to validate hydrological models, bears the advantage that not only the amount of transported solute needs to be correctly simulated but also the concentration of the modeled tracer needs to be correctly accounted for. Model structures derived by such a tracer driven calibration procedure thereby are more likely to represent the actual nature of the hydrological system. Results proving the suitability of the model setup to reproduce the collected isotope data will be shown and the discharge generating

  15. Forecasting carbon budget under climate change and CO 2 fertilization for subtropical region in China using integrated biosphere simulator (IBIS) model

    USGS Publications Warehouse

    Zhu, Q.; Jiang, H.; Liu, J.; Peng, C.; Fang, X.; Yu, S.; Zhou, G.; Wei, X.; Ju, W.

    2011-01-01

    The regional carbon budget of the climatic transition zone may be very sensitive to climate change and increasing atmospheric CO 2 concentrations. This study simulated the carbon cycles under these changes using process-based ecosystem models. The Integrated Biosphere Simulator (IBIS), a Dynamic Global Vegetation Model (DGVM), was used to evaluate the impacts of climate change and CO 2 fertilization on net primary production (NPP), net ecosystem production (NEP), and the vegetation structure of terrestrial ecosystems in Zhejiang province (area 101,800 km 2, mainly covered by subtropical evergreen forest and warm-temperate evergreen broadleaf forest) which is located in the subtropical climate area of China. Two general circulation models (HADCM3 and CGCM3) representing four IPCC climate change scenarios (HC3AA, HC3GG, CGCM-sresa2, and CGCM-sresb1) were used as climate inputs for IBIS. Results show that simulated historical biomass and NPP are consistent with field and other modelled data, which makes the analysis of future carbon budget reliable. The results indicate that NPP over the entire Zhejiang province was about 55 Mt C yr -1 during the last half of the 21 st century. An NPP increase of about 24 Mt C by the end of the 21 st century was estimated with the combined effects of increasing CO 2 and climate change. A slight NPP increase of about 5 Mt C was estimated under the climate change alone scenario. Forests in Zhejiang are currently acting as a carbon sink with an average NEP of about 2.5 Mt C yr -1. NEP will increase to about 5 Mt C yr -1 by the end of the 21 st century with the increasing atmospheric CO 2 concentration and climate change. However, climate change alone will reduce the forest carbon sequestration of Zhejiang's forests. Future climate warming will substantially change the vegetation cover types; warm-temperate evergreen broadleaf forest will be gradually substituted by subtropical evergreen forest. An increasing CO 2 concentration will have

  16. Forecasting carbon budget under climate change and CO2 fertilization for subtropical region in China using integrated biosphere simulator (IBIS) model

    USGS Publications Warehouse

    Zhu, Q.; Jiang, H.; Liu, J.; Peng, C.; Fang, X.; Yu, S.; Zhou, G.; Wei, X.; Ju, W.

    2011-01-01

    The regional carbon budget of the climatic transition zone may be very sensitive to climate change and increasing atmospheric CO2 concentrations. This study simulated the carbon cycles under these changes using process-based ecosystem models. The Integrated Biosphere Simulator (IBIS), a Dynamic Global Vegetation Model (DGVM), was used to evaluate the impacts of climate change and CO2 fertilization on net primary production (NPP), net ecosystem production (NEP), and the vegetation structure of terrestrial ecosystems in Zhejiang province (area 101,800 km2, mainly covered by subtropical evergreen forest and warm-temperate evergreen broadleaf forest) which is located in the subtropical climate area of China. Two general circulation models (HADCM3 and CGCM3) representing four IPCC climate change scenarios (HC3AA, HC3GG, CGCM-sresa2, and CGCM-sresb1) were used as climate inputs for IBIS. Results show that simulated historical biomass and NPP are consistent with field and other modelled data, which makes the analysis of future carbon budget reliable. The results indicate that NPP over the entire Zhejiang province was about 55 Mt C yr-1 during the last half of the 21st century. An NPP increase of about 24 Mt C by the end of the 21st century was estimated with the combined effects of increasing CO2 and climate change. A slight NPP increase of about 5 Mt C was estimated under the climate change alone scenario. Forests in Zhejiang are currently acting as a carbon sink with an average NEP of about 2.5 Mt C yr-1. NEP will increase to about 5 Mt C yr-1 by the end of the 21st century with the increasing atmospheric CO2 concentration and climate change. However, climate change alone will reduce the forest carbon sequestration of Zhejiang's forests. Future climate warming will substantially change the vegetation cover types; warm-temperate evergreen broadleaf forest will be gradually substituted by subtropical evergreen forest. An increasing CO2 concentration will have little

  17. Dynamics of soil available phosphorus and its impact factors under simulated climate change in typical farmland of Taihu Lake region, China.

    PubMed

    Yu, Kaihao; Chen, Xiaomin; Pan, Genxing; Zhang, Xuhui; Chen, Can

    2016-02-01

    Global climate change affects the availability of soil nutrients, thereby influencing crop productivity. This research was conducted to investigate the effects of elevated CO2, elevated temperature, and the interaction of the elevated CO2 and temperature on the soil available phosphorus (P) of a paddy-wheat rotation in the Taihu Lake region, China. Winter wheat (Triticum aestivum L.) was cultivated during the study period from 2011 to 2014 at two CO2 levels (350 μL•L(-1) ambient and 500 μL•L(-1) elevated by 150 μL•L(-1)) and two temperatures (ambient and 2 °C above the ambient). Soil available P content increased at the first season and decreased at the last season during the three wheat growing seasons. Soil available P content showed seasonal variation, whereas dynamic changes were not significant within each growing season. Soil available P content had no obvious trends under different treatments. But for the elevated temperature, CO2, and their combination treatments, soil available P content decreased in a long time period. During the period of wheat ripening stage, significant positive correlations were found between soil available P content and saturated hydraulic conductivity (Ks) and organic matter, but significant negative correlations with soil clay content and pH value; the correlation coefficients were 0.9400 (p < 0.01), 0.9942 (p < 0.01), -0.9383 (p < 0.01), and -0.6403 (p < 0.05), respectively. Therefore, Ks, organic matter, soil clay, and pH were the major impact factors on soil available P content. These results can provide a basis for predicting the trend of soil available P variation, as well as guidance for managing the soil nutrients and best fertilization practices in the future climate change scenario. PMID:26769701

  18. TRS-PCR profiling for discrimination of Escherichia coli strains isolated from children with diarrhea under 5 years of age in Lodz region, Poland.

    PubMed

    Kubiak-Szeligowska, Anna B; Bartnicka, Milena; Jarych, Dariusz; Majchrzak, Marta

    2016-09-01

    Escherichia coli is one of the most frequently isolated gram-negative pathogens in cases of foodborne diseases and hospital infections. What is more, diarrheal diseases, including these associated with pathogenic E. coli strains, are leading causes of morbidity and mortality worldwide, especially among children. Improvements of the management of diarrheal diseases caused by these bacteria are in the spotlight of the World Health Organization. Therefore, there is still a need to develop new methods or improve ones that are commonly used to characterize and distinguish E. coli strains more precisely. In this work, TRS-based PCRs were effectively used for discrimination of 123 E. coli strains isolated from children with diarrhea in the Lodz region (Poland). The composite TRS-PCR approach, based on similarity comparisons of GTG-PCR and CGG-PCR fingerprints, enabled us to distinguish strains with very good efficacy. This was confirmed by the high diversity index (0.991) and high reproducibility of the band patterns obtained (95.0 %). These results showed the great variation in strains that may cause infections in children under 38 months. However, the stains were grouped in three separate clusters, which were different in terms of their phylogenetic affiliation and virulence factor repertoire. The obtained results support and are consistent with the need of public health surveillance for searching new and fast assays as far as children's health is concerned. TRS-PCR profiling is an effective tool for genotyping of E. coli strains isolated from children with diarrhea. PMID:27389591

  19. The Effect of Improved Water Supply on Diarrhea Prevalence of Children under Five in the Volta Region of Ghana: A Cluster-Randomized Controlled Trial

    PubMed Central

    Cha, Seungman; Kang, Douk; Tuffuor, Benedict; Lee, Gyuhong; Cho, Jungmyung; Chung, Jihye; Kim, Myongjin; Lee, Hoonsang; Lee, Jaeeun; Oh, Chunghyeon

    2015-01-01

    Although a number of studies have been conducted to explore the effect of water quality improvement, the majority of them have focused mainly on point-of-use water treatment, and the studies investigating the effect of improved water supply have been based on observational or inadequately randomized trials. We report the results of a matched cluster randomized trial investigating the effect of improved water supply on diarrheal prevalence of children under five living in rural areas of the Volta Region in Ghana. We compared the diarrheal prevalence of 305 children in 10 communities of intervention with 302 children in 10 matched communities with no intervention (October 2012 to February 2014). A modified Poisson regression was used to estimate the prevalence ratio. An intention-to-treat analysis was undertaken. The crude prevalence ratio of diarrhea in the intervention compared with the control communities was 0.85 (95% CI 0.74–0.97) for Krachi West, 0.96 (0.87–1.05) for Krachi East, and 0.91 (0.83–0.98) for both districts. Sanitation was adjusted for in the model to remove the bias due to residual imbalance since it was not balanced even after randomization. The adjusted prevalence ratio was 0.82 (95% CI 0.71–0.96) for Krachi West, 0.95 (0.86–1.04) for Krachi East, and 0.89 (0.82–0.97) for both districts. This study provides a basis for a better approach to water quality interventions. PMID:26404337

  20. Paeonol Protects Rat Heart by Improving Regional Blood Perfusion during No-Reflow.

    PubMed

    Ma, Lina; Chuang, Chia-Chen; Weng, Weiliang; Zhao, Le; Zheng, Yongqiu; Zhang, Jinyan; Zuo, Li

    2016-01-01

    No-reflow phenomenon, defined as inadequate perfusion of myocardium without evident artery obstruction, occurs at a high incidence after coronary revascularization. The mechanisms underlying no-reflow is only partially understood. It is commonly caused by the swelling of endothelial cells, neutrophil accumulation, and vasoconstriction, which are all related to acute inflammation. Persistent no-reflow can lead to hospitalization and mortality. However, an effective preventive intervention has not yet been established. We have previously found that paeonol, an active extraction from the root of Paeonia suffruticosa, can benefit the heart function by inhibiting tissue damage after ischemia, reducing inflammation, and inducing vasodilatation. To further investigate the potential cardioprotective action of paeonol on no-reflow, healthy male Wistar rats were randomly divided into four groups: sham, ischemia-reperfusion (I/R) injury (left anterior descending coronary artery was ligated for 4 h followed by reperfusion for 8 h), and I/R injury pretreated with paeonol at two different doses. Real-time myocardial contrast echocardiography was used to monitor regional blood perfusion and cardiac functions. Our data indicated that paeonol treatment significantly reduces myocardial infarct area and no-reflow area (n = 8; p < 0.05). Regional myocardial perfusion (A·β) and cardiac functions such as ejection fraction, stroke volume, and fractional shortening were elevated by paeonol (n = 8; p < 0.05). Paeonol also lowered the serum levels of lactate dehydrogenase, creatine kinase, cardiac troponin T, and C-reactive protein, as indices of myocardial injury. Paeonol exerts beneficial effects on attenuating I/R-associated no-reflow injuries, and may be considered as a potential preventive treatment for cardiac diseases or post-coronary revascularization in which no-reflow often occurs. PMID:27493631

  1. Paeonol Protects Rat Heart by Improving Regional Blood Perfusion during No-Reflow

    PubMed Central

    Ma, Lina; Chuang, Chia-Chen; Weng, Weiliang; Zhao, Le; Zheng, Yongqiu; Zhang, Jinyan; Zuo, Li

    2016-01-01

    No-reflow phenomenon, defined as inadequate perfusion of myocardium without evident artery obstruction, occurs at a high incidence after coronary revascularization. The mechanisms underlying no-reflow is only partially understood. It is commonly caused by the swelling of endothelial cells, neutrophil accumulation, and vasoconstriction, which are all related to acute inflammation. Persistent no-reflow can lead to hospitalization and mortality. However, an effective preventive intervention has not yet been established. We have previously found that paeonol, an active extraction from the root of Paeonia suffruticosa, can benefit the heart function by inhibiting tissue damage after ischemia, reducing inflammation, and inducing vasodilatation. To further investigate the potential cardioprotective action of paeonol on no-reflow, healthy male Wistar rats were randomly divided into four groups: sham, ischemia-reperfusion (I/R) injury (left anterior descending coronary artery was ligated for 4 h followed by reperfusion for 8 h), and I/R injury pretreated with paeonol at two different doses. Real-time myocardial contrast echocardiography was used to monitor regional blood perfusion and cardiac functions. Our data indicated that paeonol treatment significantly reduces myocardial infarct area and no-reflow area (n = 8; p < 0.05). Regional myocardial perfusion (A·β) and cardiac functions such as ejection fraction, stroke volume, and fractional shortening were elevated by paeonol (n = 8; p < 0.05). Paeonol also lowered the serum levels of lactate dehydrogenase, creatine kinase, cardiac troponin T, and C-reactive protein, as indices of myocardial injury. Paeonol exerts beneficial effects on attenuating I/R-associated no-reflow injuries, and may be considered as a potential preventive treatment for cardiac diseases or post-coronary revascularization in which no-reflow often occurs. PMID:27493631

  2. Efficient Production of Bacillus thuringiensis Cry1AMod Toxins under Regulation of cry3Aa Promoter and Single Cysteine Mutations in the Protoxin Region

    PubMed Central

    García-Gómez, Blanca I.; Sánchez, Jorge; Martínez de Castro, Diana L.; Ibarra, Jorge E.; Bravo, Alejandra

    2013-01-01

    Bacillus thuringiensis Cry1AbMod toxins are engineered versions of Cry1Ab that lack the amino-terminal end, including domain I helix α-1 and part of helix α-2. This deletion improves oligomerization of these toxins in solution in the absence of cadherin receptor and counters resistance to Cry1A toxins in different lepidopteran insects, suggesting that oligomerization plays a major role in their toxicity. However, Cry1AbMod toxins are toxic to Escherichia coli cells, since the cry1A promoter that drives its expression in B. thuringiensis has readthrough expression activity in E. coli, making difficult the construction of these CryMod toxins. In this work, we show that Cry1AbMod and Cry1AcMod toxins can be cloned efficiently under regulation of the cry3A promoter region to drive its expression in B. thuringiensis without expression in E. coli cells. However, p3A-Cry1Ab(c)Mod construction promotes the formation of Cry1AMod crystals in B. thuringiensis cells that were not soluble at pH 10.5 and showed no toxicity to Plutella xylostella larvae. Cysteine residues in the protoxin carboxyl-terminal end of Cry1A toxins have been shown to be involved in disulfide bond formation, which is important for crystallization. Six individual cysteine substitutions for serine residues were constructed in the carboxyl-terminal protoxin end of the p3A-Cry1AbMod construct and one in the carboxyl-terminal protoxin end of p3A-Cry1AcMod. Interestingly, p3A-Cry1AbMod C654S and C729S and p3A-Cry1AcMod C730S recover crystal solubility at pH 10.5 and toxicity to P. xylostella. These results show that combining the cry3A promoter expression system with single cysteine mutations is a useful system for efficient expression of Cry1AMod toxins in B. thuringiensis. PMID:24014526

  3. Regionalization of the axial skeleton in the ‘ambush predator’ guild – are there developmental rules underlying body shape evolution in ray-finned fishes?

    PubMed Central

    2013-01-01

    Background A long, slender body plan characterized by an elongate antorbital region and posterior displacement of the unpaired fins has evolved multiple times within ray-finned fishes, and is associated with ambush predation. The axial skeleton of ray-finned fishes is divided into abdominal and caudal regions, considered to be evolutionary modules. In this study, we test whether the convergent evolution of the ambush predator body plan is associated with predictable, regional changes in the axial skeleton, specifically whether the abdominal region is preferentially lengthened relative to the caudal region through the addition of vertebrae. We test this hypothesis in seven clades showing convergent evolution of this body plan, examining abdominal and caudal vertebral counts in over 300 living and fossil species. In four of these clades, we also examined the relationship between the fineness ratio and vertebral regionalization using phylogenetic independent contrasts. Results We report that in five of the clades surveyed, Lepisosteidae, Esocidae, Belonidae, Sphyraenidae and Fistulariidae, vertebrae are added preferentially to the abdominal region. In Lepisosteidae, Esocidae, and Belonidae, increasing abdominal vertebral count was also significantly related to increasing fineness ratio, a measure of elongation. Two clades did not preferentially add abdominal vertebrae: Saurichthyidae and Aulostomidae. Both of these groups show the development of a novel caudal region anterior to the insertion of the anal fin, morphologically differentiated from more posterior caudal vertebrae. Conclusions The preferential addition of abdominal vertebrae in fishes with an elongate body shape is consistent with the existence of a conservative positioning module formed by the boundary between the abdominal and caudal vertebral regions and the anterior insertion of the anal fin. Dissociation of this module is possible, although less probable than changes in the independently evolving

  4. Environmental Response and Genomic Regions Correlated with Rice Root Growth and Yield under Drought in the OryzaSNP Panel across Multiple Study Systems.

    PubMed

    Wade, Len J; Bartolome, Violeta; Mauleon, Ramil; Vasant, Vivek Deshmuck; Prabakar, Sumeet Mankar; Chelliah, Muthukumar; Kameoka, Emi; Nagendra, K; Reddy, K R Kamalnath; Varma, C Mohan Kumar; Patil, Kalmeshwar Gouda; Shrestha, Roshi; Al-Shugeairy, Zaniab; Al-Ogaidi, Faez; Munasinghe, Mayuri; Gowda, Veeresh; Semon, Mande; Suralta, Roel R; Shenoy, Vinay; Vadez, Vincent; Serraj, Rachid; Shashidhar, H E; Yamauchi, Akira; Babu, Ranganathan Chandra; Price, Adam; McNally, Kenneth L; Henry, Amelia

    2015-01-01

    The rapid progress in rice genotyping must be matched by advances in phenotyping. A better understanding of genetic variation in rice for drought response, root traits, and practical methods for studying them are needed. In this study, the OryzaSNP set (20 diverse genotypes that have been genotyped for SNP markers) was phenotyped in a range of field and container studies to study the diversity of rice root growth and response to drought. Of the root traits measured across more than 20 root experiments, root dry weight showed the most stable genotypic performance across studies. The environment (E) component had the strongest effect on yield and root traits. We identified genomic regions correlated with root dry weight, percent deep roots, maximum root depth, and grain yield based on a correlation analysis with the phenotypes and aus, indica, or japonica introgression regions using the SNP data. Two genomic regions were identified as hot spots in which root traits and grain yield were co-located; on chromosome 1 (39.7-40.7 Mb) and on chromosome 8 (20.3-21.9 Mb). Across experiments, the soil type/ growth medium showed more correlations with plant growth than the container dimensions. Although the correlations among studies and genetic co-location of root traits from a range of study systems points to their potential utility to represent responses in field studies, the best correlations were observed when the two setups had some similar properties. Due to the co-location of the identified genomic regions (from introgression block analysis) with QTL for a number of previously reported root and drought traits, these regions are good candidates for detailed characterization to contribute to understanding rice improvement for response to drought. This study also highlights the utility of characterizing a small set of 20 genotypes for root growth, drought response, and related genomic regions. PMID:25909711

  5. Environmental Response and Genomic Regions Correlated with Rice Root Growth and Yield under Drought in the OryzaSNP Panel across Multiple Study Systems

    PubMed Central

    Wade, Len J.; Bartolome, Violeta; Mauleon, Ramil; Vasant, Vivek Deshmuck; Prabakar, Sumeet Mankar; Chelliah, Muthukumar; Kameoka, Emi; Nagendra, K.; Reddy, K. R. Kamalnath; Varma, C. Mohan Kumar; Patil, Kalmeshwar Gouda; Shrestha, Roshi; Al-Shugeairy, Zaniab; Al-Ogaidi, Faez; Munasinghe, Mayuri; Gowda, Veeresh; Semon, Mande; Suralta, Roel R.; Shenoy, Vinay; Vadez, Vincent; Serraj, Rachid; Shashidhar, H. E.; Yamauchi, Akira; Babu, Ranganathan Chandra; Price, Adam; McNally, Kenneth L.; Henry, Amelia

    2015-01-01

    The rapid progress in rice genotyping must be matched by advances in phenotyping. A better understanding of genetic variation in rice for drought response, root traits, and practical methods for studying them are needed. In this study, the OryzaSNP set (20 diverse genotypes that have been genotyped for SNP markers) was phenotyped in a range of field and container studies to study the diversity of rice root growth and response to drought. Of the root traits measured across more than 20 root experiments, root dry weight showed the most stable genotypic performance across studies. The environment (E) component had the strongest effect on yield and root traits. We identified genomic regions correlated with root dry weight, percent deep roots, maximum root depth, and grain yield based on a correlation analysis with the phenotypes and aus, indica, or japonica introgression regions using the SNP data. Two genomic regions were identified as hot spots in which root traits and grain yield were co-located; on chromosome 1 (39.7–40.7 Mb) and on chromosome 8 (20.3–21.9 Mb). Across experiments, the soil type/ growth medium showed more correlations with plant growth than the container dimensions. Although the correlations among studies and genetic co-location of root traits from a range of study systems points to their potential utility to represent responses in field studies, the best correlations were observed when the two setups had some similar properties. Due to the co-location of the identified genomic regions (from introgression block analysis) with QTL for a number of previously reported root and drought traits, these regions are good candidates for detailed characterization to contribute to understanding rice improvement for response to drought. This study also highlights the utility of characterizing a small set of 20 genotypes for root growth, drought response, and related genomic regions. PMID:25909711

  6. Policy Statement on Future Competitions for Regional Educational Laboratories and Educational Research and Development Centers under Section 405(f) of the General Education Provisions Act.

    ERIC Educational Resources Information Center

    National Inst. of Education (ED), Washington, DC.

    A National Institute of Education (NIE) policy statement is presented regarding competition for future funding of regional educational laboratories and research and development (R&D) centers with appropriations available for Section 405(f) of the General Education Provisions Act (GEPA). Attention is also directed to continuing eligibility of the…

  7. Comparative Study of Vocational Education and Training Systems: National Vocational Education and Training Systems across Three Regions under Pressure of Change. Review of Research.

    ERIC Educational Resources Information Center

    Keating, J.; Medrich, E.; Volkoff, V.; Perry, J.

    A study to compare vocational education and training (VET) systems examined nine countries across these three large geographical regions: Europe, East Asia, and the Americas. It explored variables that most define and influence characteristics, behavior, and apparent success of VET systems and the impact of change. The nine systems were chosen on…

  8. Trypanosoma cruzi Lineages Detected in Congenitally Infected Infants and Triatoma infestans from the Same Disease-Endemic Region under Entomologic Surveillance in Paraguay

    PubMed Central

    del Puerto, Florencia; Sánchez, Zunilda; Nara, Eva; Meza, Graciela; Paredes, Berta; Ferreira, Elizabeth; Russomando, Graciela

    2010-01-01

    Trypanosoma cruzi II is associated with Chagas disease in the southern part of South America. We analyzed T. cruzi variants in field-collected triatomines and congenitally infected infants living in the same disease-endemic region in Paraguay. Results of polymerase chain reactions for T. cruzi kinetoplast DNA and satellite DNA were positive in 83 triatomine feces samples and 58 infant blood samples. However, lineages were detected in 33 and 38 samples, respectively. Trypanosoma cruzi genotypes were determined in 56 (97%) blood samples after hybridization by using specific probes. The Tc I genotype was not detected. The prevalent sublineage was Tc IId in triatomines (27 of 33) and infant blood (36 of 58) as assessed by amplification of the 24Sα ribosomal RNA and the mini-exon region genes. The Tc IIc genotype was detected in 20 infant blood samples and in 1 triatomine. This study shows T. cruzi II is the predominant lineage circulating in triatomines and humans in endemic areas of eastern region of Paraguay. PMID:20207861

  9. Global, regional, and national levels of neonatal, infant, and under-5 mortality during 1990–2013: a systematic analysis for the Global Burden of Disease Study 2013

    PubMed Central

    Wang, Haidong; Liddell, Chelsea A; Coates, Matthew M; Mooney, Meghan D; Levitz, Carly E; Schumacher, Austin E; Apfel, Henry; Iannarone, Marissa; Phillips, Bryan; Lofgren, Katherine T; Sandar, Logan; Dorrington, Rob E; Rakovac, Ivo; Jacobs, Troy A; Liang, Xiaofeng; Zhou, Maigeng; Zhu, Jun; Yang, Gonghuan; Wang, Yanping; Liu, Shiwei; Li, Yichong; Ozgoren, Ayse Abbasoglu; Abera, Semaw Ferede; Abubakar, Ibrahim; Achoki, Tom; Adelekan, Ademola; Ademi, Zanfina; Alemu, Zewdie Aderaw; Allen, Peter J; AlMazroa, Mohammad AbdulAziz; Alvarez, Elena; Amankwaa, Adansi A; Amare, Azmeraw T; Ammar, Walid; Anwari, Palwasha; Cunningham, Solveig Argeseanu; Asad, Majed Masoud; Assadi, Reza; Banerjee, Amitava; Basu, Sanjay; Bedi, Neeraj; Bekele, Tolesa; Bell, Michelle L; Bhutta, Zulfiqar; Blore, Jed; Basara, Berrak Bora; Boufous, Soufiane; Breitborde, Nicholas; Bruce, Nigel G; Bui, Linh Ngoc; Carapetis, Jonathan R; Cárdenas, Rosario; Carpenter, David O; Caso, Valeria; Castro, Ruben Estanislao; Catalá-Lopéz, Ferrán; Cavlin, Alanur; Che, Xuan; Chiang, Peggy Pei-Chia; Chowdhury, Rajiv; Christophi, Costas A; Chuang, Ting-Wu; Cirillo, Massimo; Leite, Iuri da Costa; Courville, Karen J; Dandona, Lalit; Dandona, Rakhi; Davis, Adrian; Dayama, Anand; Deribe, Kebede; Dharmaratne, Samath D; Dherani, Mukesh K; Dilmen, Uğur; Ding, Eric L; Edmond, Karen M; Ermakov, Sergei Petrovich; Farzadfar, Farshad; Fereshtehnejad, Seyed-Mohammad; Fijabi, Daniel Obadare; Foigt, Nataliya; Forouzanfar, Mohammad H; Garcia, Ana C; Geleijnse, Johanna M; Gessner, Bradford D; Goginashvili, Ketevan; Gona, Philimon; Goto, Atsushi; Gouda, Hebe N; Green, Mark A; Greenwell, Karen Fern; Gugnani, Harish Chander; Gupta, Rahul; Hamadeh, Randah Ribhi; Hammami, Mouhanad; Harb, Hilda L; Hay, Simon; Hedayati, Mohammad T; Hosgood, H Dean; Hoy, Damian G; Idrisov, Bulat T; Islami, Farhad; Ismayilova, Samaya; Jha, Vivekanand; Jiang, Guohong; Jonas, Jost B; Juel, Knud; Kabagambe, Edmond Kato; Kazi, Dhruv S; Kengne, Andre Pascal; Kereselidze, Maia; Khader, Yousef Saleh; Khalifa, Shams Eldin Ali Hassan; Khang, Young-Ho; Kim, Daniel; Kinfu, Yohannes; Kinge, Jonas M; Kokubo, Yoshihiro; Kosen, Soewarta; Defo, Barthelemy Kuate; Kumar, G Anil; Kumar, Kaushalendra; Kumar, Ravi B; Lai, Taavi; Lan, Qing; Larsson, Anders; Lee, Jong-Tae; Leinsalu, Mall; Lim, Stephen S; Lipshultz, Steven E; Logroscino, Giancarlo; Lotufo, Paulo A; Lunevicius, Raimundas; Lyons, Ronan Anthony; Ma, Stefan; Mahdi, Abbas Ali; Marzan, Melvin Barrientos; Mashal, Mohammad Taufiq; Mazorodze, Tasara T; McGrath, John J; Memish, Ziad A; Mendoza, Walter; Mensah, George A; Meretoja, Atte; Miller, Ted R; Mills, Edward J; Mohammad, Karzan Abdulmuhsin; Mokdad, Ali H; Monasta, Lorenzo; Montico, Marcella; Moore, Ami R; Moschandreas, Joanna; Msemburi, William T; Mueller, Ulrich O; Muszynska, Magdalena M; Naghavi, Mohsen; Naidoo, Kovin S; Narayan, KM Venkat; Nejjari, Chakib; Ng, Marie; Ngirabega, Jean de Dieu; Nieuwenhuijsen, Mark J; Nyakarahuka, Luke; Ohkubo, Takayoshi; Omer, Saad B; Caicedo, Angel J Paternina; Wyk, Victoria Pillay-van; Pope, Dan; Prabhakaran, Dorairaj; Rahman, Sajjad UR; Rana, Saleem M; Reilly, Robert Quentin; Rojas-Rueda, David; Ronfani, Luca; Rushton, Lesley; Saeedi, Mohammad Yahya; Salomon, Joshua; Sampson, Uchechukwu; Santos, Itamar S; Sawhney, Monika; Schmidt, Jürgen C; Nazarova, Marina Shakh; She, Jun; Sheikhbahaei, Sara; Shibuya, Kenji; Shin, Hwashin Hyun; Shishani, Kawkab; Shiue, Ivy; Sigfusdottir, Inga Dora; Singh, Jasvinder A; Skirbekk, Vegard; Sliwa, Karen; Soshnikov, Sergey S; Sposato, Luciano A; Stathopoulou, Vasiliki Kalliopi; Stroumpoulis, Konstantinos; Tabb, Karen M; Talongwa, Roberto Tchio; Teixeira, Carolina Maria; Terkawi, Abdullah Sulieman; Thomson, Alan J; Lyman, Andrew L Thorne; Toyoshima, Hideaki; Dimbuene, Zacharie Tsala; Uwaliraye, Parfait; Uzun, Selen Begüm; Vasankari, Tommi J; Vasconcelos, Ana Maria Nogales; Vlassov, Vasiliy Victorovich; Vollset, Stein Emil; Vos, Theo; Waller, Stephen; Wan, Xia; Weichenthal, Scott; Weiderpass, Elisabete; Weintraub, Robert G; Westerman, Ronny; Wilkinson, James D; Williams, Hywel C; Yang, Yang C; Yentur, Gokalp Kadri; Yip, Paul; Yonemoto, Naohiro; Younis, Mustafa; Yu, Chuanhua; Jin, Kim Yun; Zaki, Maysaa El Sayed; Zhu, Shankuan; Lopez, Alan D; Murray, Christopher J L

    2014-01-01

    Summary Background Remarkable financial and political efforts have been focused on the reduction of child mortality during the past few decades. Timely measurements of levels and trends in under-5 mortality are important to assess progress towards the Millennium Development Goal 4 (MDG 4) target of reduction of child mortality by two thirds from 1990 to 2015, and to identify models of success. Methods We generated updated estimates of child mortality in early neonatal (age 0–6 days), late neonatal (7–28 days), postneonatal (29–364 days), childhood (1–4 years), and under-5 (0–4 years) age groups for 188 countries from 1970 to 2013, with more than 29 000 survey, census, vital registration, and sample registration datapoints. We used Gaussian process regression with adjustments for bias and non-sampling error to synthesise the data for under-5 mortality for each country, and a separate model to estimate mortality for more detailed age groups. We used explanatory mixed effects regression models to assess the association between under-5 mortality and income per person, maternal education, HIV child death rates, secular shifts, and other factors. To quantify the contribution of these different factors and birth numbers to the change in numbers of deaths in under-5 age groups from 1990 to 2013, we used Shapley decomposition. We used estimated rates of change between 2000 and 2013 to construct under-5 mortality rate scenarios out to 2030. Findings We