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Sample records for ischemic preconditioning ip

  1. Preconditioning Strategies for Kidney Ischemia Reperfusion Injury: Implications of the “Time-Window” in Remote Ischemic Preconditioning

    PubMed Central

    Yoon, Young Eun; Lee, Kwang Suk; Choi, Kyung Hwa; Kim, Kwang Hyun; Yang, Seung Choul; Han, Woong Kyu

    2015-01-01

    Remote ischemic preconditioning (IP) is a potential renoprotective strategy. However, there has been no demonstrated result in large animals and the role of time window in remote IP remains to be defined. Using a single-kidney porcine model, we evaluated organ protective function of remote IP in renal ischemia reperfusion injury. Fifteen Yorkshire pigs, 20 weeks old and weighing 35–38 kg were used. One week after left nephrectomy, we performed remote IP (clamping right external iliac artery, 2 cycles of 10 minutes) and right renal artery clamping (warm ischemia; 90 minutes). The animals were randomly divided into three groups: control group, warm ischemia without IP; group 1 (remote IP with early window [IP-E]), IP followed by warm ischemia with a 10-minute time window; and group 2 (remote IP with late window [IP-L]), IP followed by warm ischemia after a 24-hour time window. There were no differences in serum creatinine changes between groups. The IP-L group had lower urinary neutrophil gelatinase-associated lipocalin than control and IP-E at 72 hours post-ischemia. At 72 hours post-ischemia, the urinary kidney injury molecule-1 (KIM-1) was lower in the IP-L group than in the control and IP-E groups, and the IP-L group KIM-1 was near pre-ischemic levels, whereas the control and IP-E group KIM-1 levels were rising. Microalbumin also tended to be lower in the IP-L group. Taken together, remote IP showed a significant reduction in renal injury biomarkers from ischemia reperfusion injury. To effectively provide kidney protection, remote IP might require a considerable, rather than short, time window of ischemia. PMID:25879855

  2. Myocardial stunning, hibernation, and ischemic preconditioning.

    PubMed

    Vroom, M B; van Wezel, H B

    1996-10-01

    From the present review, it may be concluded that myocardial ischemia results in far more complicated syndromes than previously realized. Although not all aspects of the issues discussed in this review are currently a clinical reality in the daily practice of cardiovascular anesthesiologists, the understanding and application of these concepts are growing rapidly. Indications for revascularization procedures will be adjusted in patients with evidence of hibernating myocardium. In the future, postoperative myocardial dysfunction may be diminished by the prevention of myocardial stunning, for instance by altering the composition of the cardioplegic solution and other interventions. Finally, additional advances may involve reduction of the extent of perioperative myocardial infarctions by application of ischemic preconditioning. PMID:8910163

  3. Molecular mechanisms of ischemic preconditioning in the kidney.

    PubMed

    Kapitsinou, Pinelopi P; Haase, Volker H

    2015-11-15

    More effective therapeutic strategies for the prevention and treatment of acute kidney injury (AKI) are needed to improve the high morbidity and mortality associated with this frequently encountered clinical condition. Ischemic and/or hypoxic preconditioning attenuates susceptibility to ischemic injury, which results from both oxygen and nutrient deprivation and accounts for most cases of AKI. While multiple signaling pathways have been implicated in renoprotection, this review will focus on oxygen-regulated cellular and molecular responses that enhance the kidney's tolerance to ischemia and promote renal repair. Central mediators of cellular adaptation to hypoxia are hypoxia-inducible factors (HIFs). HIFs play a crucial role in ischemic/hypoxic preconditioning through the reprogramming of cellular energy metabolism, and by coordinating adenosine and nitric oxide signaling with antiapoptotic, oxidative stress, and immune responses. The therapeutic potential of HIF activation for the treatment and prevention of ischemic injuries will be critically examined in this review. PMID:26311114

  4. Comparing various surgical delay methods with ischemic preconditioning in the rat TRAM flap model.

    PubMed

    Cinpolat, Ani; Bektas, Gamze; Coskunfirat, Nesil; Rizvanovic, Zumreta; Coskunfirat, O Koray

    2014-06-01

    Both surgical delay and ischemic preconditioning (IP) have been shown to be effective in improving the survival of flaps. We used a variety of flap delay methods and IP to increase the surviving area of the transverse rectus abdominis musculocutaneous (TRAM) flap in rats, and the results are compared in between. A 6-× 3-cm-sized TRAM flap in 40 Wistar rats was allocated into five groups. Group 1: TRAM flap was elevated from nondominant pedicle, and the flap was sutured to the original bed. Group 2: Left superior deep epigastric vessels (SDEV) were cut; 1 week later, TRAM flap was elevated. Group 3: Only skin incision was done; 1 week later, TRAM flap was elevated. Group 4: Skin incision was done, and the left SDEV were cut; 1 week later, TRAM flap was elevated. Group 5: TRAM flap was elevated; IP was performed using three cycles of 10 minutes of repeated ischemia/reperfusion (I/R) periods, and the flap was sutured to the original bed. The surviving area of the flap was statistically significant between the control and groups 2, 4, and 5 (p < 0.001), and groups 4 and 2 were superior to group 5. Although preconditioning has been intensively studied for the last two decades and partly provided its beneficial effects in I/R injury, we determined the IP increased the surviving area of the TRAM flap but not effective as much as surgical delay method. PMID:24347333

  5. Ischemic preconditioning enhances integrity of coronary endothelial tight junctions

    SciTech Connect

    Li, Zhao; Jin, Zhu-Qiu

    2012-08-31

    Highlights: Black-Right-Pointing-Pointer Cardiac tight junctions are present between coronary endothelial cells. Black-Right-Pointing-Pointer Ischemic preconditioning preserves the structural and functional integrity of tight junctions. Black-Right-Pointing-Pointer Myocardial edema is prevented in hearts subjected to ischemic preconditioning. Black-Right-Pointing-Pointer Ischemic preconditioning enhances translocation of ZO-2 from cytosol to cytoskeleton. -- Abstract: Ischemic preconditioning (IPC) is one of the most effective procedures known to protect hearts against ischemia/reperfusion (IR) injury. Tight junction (TJ) barriers occur between coronary endothelial cells. TJs provide barrier function to maintain the homeostasis of the inner environment of tissues. However, the effect of IPC on the structure and function of cardiac TJs remains unknown. We tested the hypothesis that myocardial IR injury ruptures the structure of TJs and impairs endothelial permeability whereas IPC preserves the structural and functional integrity of TJs in the blood-heart barrier. Langendorff hearts from C57BL/6J mice were prepared and perfused with Krebs-Henseleit buffer. Cardiac function, creatine kinase release, and myocardial edema were measured. Cardiac TJ function was evaluated by measuring Evans blue-conjugated albumin (EBA) content in the extravascular compartment of hearts. Expression and translocation of zonula occludens (ZO)-2 in IR and IPC hearts were detected with Western blot. A subset of hearts was processed for the observation of ultra-structure of cardiac TJs with transmission electron microscopy. There were clear TJs between coronary endothelial cells of mouse hearts. IR caused the collapse of TJs whereas IPC sustained the structure of TJs. IR increased extravascular EBA content in the heart and myocardial edema but decreased the expression of ZO-2 in the cytoskeleton. IPC maintained the structure of TJs. Cardiac EBA content and edema were reduced in IPC hearts. IPC enhanced the translocation of ZO-2 from cytosol to cytoskeleton. In conclusion, TJs occur in normal mouse heart. IPC preserves the integrity of TJ structure and function that are vulnerable to IR injury.

  6. Remote Ischemic Preconditioning for Kidney Protection: GSK3?-Centric Insights Into the Mechanism of Action.

    PubMed

    Liu, Zhangsuo; Gong, Rujun

    2015-11-01

    Preventing acute kidney injury (AKI) in high-risk patients following medical interventions is a paramount challenge for clinical practice. Recent data from animal experiments and clinical trials indicate that remote ischemic preconditioning, represented by limb ischemic preconditioning, confers a protective action on the kidney. Ischemic preconditioning is effective in reducing the risk for AKI following cardiovascular interventions and the use of iodinated radiocontrast media. Nevertheless, the underlying mechanisms for this protective effect are elusive. A protective signal is conveyed from the remote site undergoing ischemic preconditioning, such as the limb, to target organs, such as the kidney, by multiple potential communication pathways, which may involve humoral, neuronal, and systemic mechanisms. Diverse transmitting pathways trigger a variety of signaling cascades, including the reperfusion injury salvage kinase and survivor activating factor enhancement pathways, all of which converge on glycogen synthase kinase 3? (GSK3?). Inhibition of GSK3? subsequent to ischemic preconditioning reinforces the Nrf2-mediated antioxidant defense, diminishes the nuclear factor-?B-dependent proinflammatory response, and exerts prosurvival effects ensuing from the desensitized mitochondria permeability transition. Thus, therapeutic targeting of GSK3? by ischemic preconditioning or by pharmacologic preconditioning with existing US Food and Drug Administration-approved drugs having GSK3?-inhibitory activities might represent a pragmatic and cost-effective adjuvant strategy for kidney protection and prophylaxis against AKI. PMID:26271146

  7. Concepts of hypoxic NO signaling in remote ischemic preconditioning

    PubMed Central

    Totzeck, Matthias; Hendgen-Cotta, Ulrike; Rassaf, Tienush

    2015-01-01

    Acute coronary syndromes remain a leading single cause of death worldwide. Therapeutic strategies to treat cardiomyocyte threatening ischemia/reperfusion injury are urgently needed. Remote ischemic preconditioning (rIPC) applied by brief ischemic episodes to heart-distant organs has been tested in several clinical studies, and the major body of evidence points to beneficial effects of rIPC for patients. The underlying signaling, however, remains incompletely understood. This relates particularly to the mechanism by which the protective signal is transferred from the remote site to the target organ. Many pathways have been forwarded but none can explain the protective effects completely. In light of recent experimental studies, we here outline the current knowledge relating to the generation of the protective signal in the remote organ, the signal transfer to the target organ and the transduction of the transferred signal into cardioprotection. The majority of studies favors a humoral factor that activates cardiomyocyte downstream signaling - receptor-dependent and independently. Cellular targets include deleterious calcium (Ca2+) signaling, reactive oxygen species, mitochondrial function and structure, and cellular apoptosis and necrosis. Following an outline of the existing evidence, we will furthermore characterize the existing knowledge and discuss future perspectives with particular emphasis on the interaction between the recently discovered hypoxic nitrite-nitric oxide signaling in rIPC. This refers to the protective role of nitrite, which can be activated endogenously using rIPC and which then contributes to cardioprotection by rIPC. PMID:26516418

  8. Protective effects of remote ischemic preconditioning in isolated rat hearts

    PubMed Central

    Teng, Xiao; Yuan, Xin; Tang, Yue; Shi, Jingqian

    2015-01-01

    To use Langendorff model to investigate whether remote ischemic preconditioning (RIPC) attenuates post-ischemic mechanical dysfunction on isolated rat heart and to explore possible mechanisms. SD rats were randomly divided into RIPC group, RIPC + norepinephrine (NE) depletion group, RIPC + pertussis toxin (PTX) pretreatment group, ischemia/reperfusion group without treatment (ischemia group) and time control (TC) group. RIPC was achieved through interrupted occlusion of anterior mesenteric artery. Then, Langendorff model was established using routine methods. Heart function was tested; immunohistochemistry and ELISA methods were used to detect various indices related to myocardial injury. Compared with ischemia group in which the hemodynamic parameters deteriorated significantly, heart function recovered to a certain degree among the RIPC, RIPC + NE depletion, and RIPC + PTX groups (P<0.05). More apoptotic nuclei were observed in ischemia group than in the other three groups (P<0.05); more apoptotic nuclei were detected in NE depletion and PTX groups than in RIPC group (P<0.05). While, there was no significant difference between NE depletion and PTX groups. In conclusion, RIPC protection on I/R myocardium extends to the period after hearts are isolated. NE and PTX-sensitive inhibitory G protein might have a role in the protection process. PMID:26550168

  9. Inhalational anesthetics as neuroprotectants or chemical preconditioning agents in ischemic brain

    PubMed Central

    Kitano, Hideto; Kirsch, Jeffrey R; Hurn, Patricia D; Murphy, Stephanie J

    2008-01-01

    This review will focus on inhalational anesthetic neuroprotection during cerebral ischemia and inhalational anesthetic preconditioning before ischemic brain injury. The limitations and challenges of past and current research in this area will be addressed before reviewing experimental and clinical studies evaluating the effects of inhalational anesthetics before and during cerebral ischemia. Mechanisms underlying volatile anesthetic neuroprotection and preconditioning will also be examined. Lastly, future directions for inhalational anesthetics and ischemic brain injury will be briefly discussed. PMID:17047683

  10. Remote ischemic preconditioning delays fatigue development during handgrip exercise.

    PubMed

    Barbosa, T C; Machado, A C; Braz, I D; Fernandes, I A; Vianna, L C; Nobrega, A C L; Silva, B M

    2015-06-01

    Ischemic preconditioning (IPC) of one or two limbs improves performance of exercise that recruits the same limb(s). However, it is unclear whether IPC application to another limb than that in exercise is also effective and which mechanisms are involved. We investigated the effect of remote IPC (RIPC) on muscle fatigue, time to task failure, forearm hemodynamics, and deoxygenation during handgrip exercise. Thirteen men underwent RIPC in the lower limbs or a control intervention (CON), in random order, and then performed a constant load rhythmic handgrip protocol until task failure. Rates of contraction and relaxation (?Force/?Time) were used as indices of fatigue. Brachial artery blood flow and conductance, besides forearm microvascular deoxygenation, were assessed during exercise. RIPC attenuated the slowing of contraction and relaxation throughout exercise (P??0.05). In conclusion, RIPC applied to the lower limbs delayed the development of fatigue during handgrip exercise, prolonged time to task failure, but was not accompanied by changes in forearm hemodynamics and deoxygenation. PMID:24731023

  11. What Happened if Various Kinds of Postconditioning Working on the Preconditioned Ischemic Skin Flaps

    PubMed Central

    Huang, Lin

    2013-01-01

    Objective: Ischemic pre-conditioning and post-conditioning are useful manipulations to reduce the undesirable effects of ischemia-reperfusion skin flap each. But the impact of post-conditioning on the pre-conditioning skin flap is not manifested. Here we investigated the influence of ischemic post-conditioning in a preconditioned axial pattern skin flap model. Method: We used the skin flap in 40 rabbits and divided them into 5 groups randomly. At first we induced the ischemic pre-conditioning of the flap which was applied by 2 periods of 15 minutes of ischemia/15 minutes of reperfusion cycle. Next post-conditioning was performed by 6 cycles of 10 seconds of repeated ischemia/reperfusion periods at different times of just after the reperfusion,5 minutes after the reperfusion,10 minutes after the reperfusion. The animals were allocated into 5 groups: group 1 (Ischemia Group); group 2: (Pre-conditioning Group); group 3: (Pre-conditioning+ Post-conditioning Group); group 4 (Pre-conditioning+ Post-conditioning 5 minutes later Group); group5 (Pre-conditioning+ Post-conditioning 10 minutes later). The neutrophil count was assessed with histologic analysis before the dissection of the skin flap. Flap viability was assessed 1 week after the operation, and surviving flap area was recorded as a percentage of the whole flap area. LSD test was used for statistical analysis among different groups to evaluate the effects of ischemic pre-conditioning against ischemia. Result: Among the varying groups, the neutrophil count varied: Group 1 was50.12±5.91; Group 2, 30.00±2.00, and Group 3, 18.87±3; Group 4, 22.50±1.92; Group 5, 30.12±1.88.The mean± SD surviving areas of the flaps for groups 1, 2, 3, 4 and 5 were 31.76±4.59, 51.26±3.24,82.18±5.28,66.85±3.87 and 51.13±2.90 respectively. Spearman correlation analysis shows an increase relation between neutrophil count and flap survival rate in the different groups (P <0.05). Conclusion: Ischemic post-conditioning has protective effect on ischemic preconditioned skin flaps, but the post-conditioning should be performed within 5 minutes after the end of ischemia. PMID:24147150

  12. Enhanced cell volume regulation: a key mechanism in local and remote ischemic preconditioning.

    PubMed

    Diaz, Roberto J; Harvey, Kordan; Boloorchi, Azadeh; Hossain, Taneya; Hinek, Alina; Backx, Peter H; Wilson, Gregory J

    2014-06-15

    We have previously shown that ischemic preconditioning (IPC) protection against necrosis in whole hearts and in both fresh and cultured cardiomyocytes, as well as the improved regulatory volume decrease to hypoosmotic swelling in cardiomyocytes, is abrogated through Cl(-) channel blockade, pointing to a role for enhanced cell volume regulation in IPC. To further define this cardioprotective mechanism, cultured rabbit ventricular cardiomyocytes were preconditioned either by 10-min simulated ischemia (SI) followed by 10-min simulated reperfusion (SR), by 10-min exposure/10-min washout of remote IPC (rIPC) plasma dialysate (from rabbits subjected to repetitive limb ischemia), or by adenoviral transfection with the constitutively active PKC-? gene. These interventions were done before cardiomyocytes were subjected to either 60- or 75-min SI/60-min SR to assess cell necrosis (by trypan blue staining), 30-min SI to assess ischemic cell swelling, or 30-min hypoosmotic (200 mosM) stress to assess cell volume regulation. Necrosis after SI/SR and both SI- and hypoosmotic stress-induced swelling was reduced in preconditioned cardiomyocytes compared with control cardiomyocytes (neither preconditioned nor transfected). These effects on necrosis and cell swelling were blocked by either Cl(-) channel blockade or dominant negative knockdown of inwardly rectifying K(+) channels with adenoviruses, suggesting that Cl(-) and K(+) movements across the sarcolemma are critical for cell volume regulation and, thereby, cell survival under hypoxic/ischemic conditions. Our results define enhanced cell volume regulation as a key common mechanism of cardioprotection by preconditioning in cardiomyocytes. PMID:24760980

  13. Effect of zinc supplements in the attenuated cardioprotective effect of ischemic preconditioning in hyperlipidemic rat heart.

    PubMed

    Kansal, Sunil Kumar; Jyoti, Uma; Sharma, Samridhi; Kaura, Arun; Deshmukh, Rahul; Goyal, Sandeep

    2015-06-01

    Hyperlipidemia is regarded as independent risk factor in the development of ischemic heart disease, and it can increase the myocardial susceptibility to ischemia-/reperfusion (I/R)-induced injury. Hyperlipidemia attenuates the cardioprotective response of ischemic preconditioning (IPC). The present study investigated the effect of zinc supplements in the attenuated cardioprotective effect of ischemic preconditioning in hyperlipidemic rat hearts. Hyperlipidemia was induced in rat by feeding high-fat diet (HFD) for 6 weeks then the serum lipid profile was observed. In experiment, the isolated Langendorff rat heart preparation was subjected to 4 cycles of ischemic preconditioning (IPC), then 30 min of ischemia followed by 120 min of reperfusion. Myocardial infarct size was elaborated morphologically by triphenyltetrazolium chloride (TTC) staining and biochemically by lactate dehydrogenase (LDH) and creatine kinase-MB (CK-MB) release from coronary effluent and left ventricular collagen content. However, the effect of zinc supplement, i.e., zinc pyrithione (10 ?M) perfused during reperfusion for 120 min, significantly abrogated the attenuated cardioprotective effect of ischemic preconditioning in hyperlipidemic rat heart whereas administration of chelator of this zinc ionophore, i.e., N,N,N',N'-tetrakis(2-pyridylmethyl)ethylene diamine (TPEN; 10 ?M), perfused during reperfusion 2 min before the perfusion of zinc pyrithione abrogated the cardioprotective effect of zinc supplement during experiment in hyperlipidemic rat heart. Thus, the administration of zinc supplements limits the infarct size, LDH, and CK-MB and enhanced the collagen level which suggests that the attenuated cardioprotective effect of IPC in hyperlipidemic rat is due to zinc loss during reperfusion caused by ischemia/reperfusion. PMID:25743572

  14. Decreased effectiveness of ischemic heart preconditioning in the state of chronic inflammation.

    PubMed

    Wojciechowska, M; Zar?bi?ski, M; Pawluczuk, P; Szukiewicz, D

    2015-11-01

    There is growing evidence, that beneficial effects of ischemic heart preconditioning (IPC) may be lost or limited due to diabetes, hyperlipidemia, hypertension, atherosclerosis, heart failure and senility. It is plausible, that these conditions interfere with the biochemical pathways underlying the IPC response, but the detailed explanation is not clear. Pro-inflammatory cytokines (IL-1?, IL-6, TNF-?), monocyte chemotactic protein-1 (MCP-1), histamine and many other agents used in a single dose before prolonged ischemia mimic IPC. However prolonged exposure to preconditioning mimetics leads to tolerance (tachyphylaxis). In the state of such tolerance ischemic preconditioning is no longer protective. Studies suggest that diabetes, hyperlipidemia, hypertension, atherosclerosis, heart failure and older age are accompanied by increased plasma levels of pro-inflammatory cytokines, MCP-1 and other inflammatory mediators. Therefore, we raised the hypothesis, that the reported lack of benefits of IPC in the listed states may be due to tolerance to IPC developed during prolonged exposure of the myocardium to preconditioning mimetics. PMID:26342834

  15. Remote ischemic preconditioning for prevention of high-altitude diseases: fact or fiction?

    PubMed

    Berger, Marc Moritz; Macholz, Franziska; Mairbäurl, Heimo; Bärtsch, Peter

    2015-11-15

    Preconditioning refers to exposure to brief episodes of potentially adverse stimuli and protects against injury during subsequent exposures. This was first described in the heart, where episodes of ischemia/reperfusion render the myocardium resistant to subsequent ischemic injury, which is likely caused by reactive oxygen species (ROS) and proinflammatory processes. Protection of the heart was also found when preconditioning was performed in an organ different from the target, which is called remote ischemic preconditioning (RIPC). The mechanisms causing protection seem to include stimulation of nitric oxide (NO) synthase, increase in antioxidant enzymes, and downregulation of proinflammatory cytokines. These pathways are also thought to play a role in high-altitude diseases: high-altitude pulmonary edema (HAPE) is associated with decreased bioavailability of NO and increased generation of ROS, whereas mechanisms causing acute mountain sickness (AMS) and high-altitude cerebral edema (HACE) seem to involve cytotoxic effects by ROS and inflammation. Based on these apparent similarities between ischemic damage and AMS, HACE, and HAPE, it is reasonable to assume that RIPC might be protective and improve altitude tolerance. In studies addressing high-altitude/hypoxia tolerance, RIPC has been shown to decrease pulmonary arterial systolic pressure in normobaric hypoxia (13% O2) and at high altitude (4,342 m). Our own results indicate that RIPC transiently decreases the severity of AMS at 12% O2. Thus preliminary studies show some benefit, but clearly, further experiments to establish the efficacy and potential mechanism of RIPC are needed. PMID:26089545

  16. Proteomic analysis of the hippocampus in naïve and ischemic-preconditioned rat.

    PubMed

    Nakajima, Takayuki; Hata, Ryusuke; Kondo, Tomohiro; Takenaka, Shigeo

    2015-11-15

    The hippocampus exhibits regional differences in vulnerability to ischemia, wherein pyramidal cells in the CA1 region are vulnerable to ischemia while pyramidal cells in the CA3 region and granule cells in the dentate gyrus (DG) region are relatively ischemia resistant. However, pyramidal cells in the CA1 region reportedly exhibit ischemic tolerance following exposure to a brief non-lethal period of ischemia known as ischemic preconditioning. In this study, we used proteomic analysis to examine the difference in protein expression between naïve rat CA1 and CA3/DG regions, as well as the altered protein expression in the CA1 region after 3min of ischemic preconditioning. Proteomic analysis identified ubiquitin carboxyl-terminal hydrolase isozyme L1 (UCH-L1), glutathione S-transferase ?5 (GST?5), glutamine synthetase (GS), and dynamin-1 as proteins with differential expression levels in naïve CA1 and CA3/DG regions. The difference in expression levels of GST?5 and GS between these two regions was further confirmed by western blot. Our analysis also identified aconitase2, ?-tubulin, protein-l-isoaspartate O-methiltransferase (PIMT), and voltage-dependent anion channel 1 (VDCA1) as proteins with down-regulated expression levels in the CA1 region following 3min ischemic preconditioning. The decrease in the expression of aconitase2 was also confirmed by western blot and immunohistochemical staining. The present results suggest that GST?5 and GS may be associated with ischemia-resistance in the CA3/DG region and that aconitase2 may play a part in the ischemic tolerance in the CA1 region. PMID:26342941

  17. Involvement of adenosine and standardization of aqueous extract of garlic (Allium sativum Linn.) on cardioprotective and cardiodepressant properties in ischemic preconditioning and myocardial ischemia-reperfusion induced cardiac injury

    PubMed Central

    Sharma, Ashish Kumar; Munajjam, Arshee; Vaishnav, Bhawna; Sharma, Richa; Sharma, Ashok; Kishore, Kunal; Sharma, Akash; Sharma, Divya; Kumari, Rita; Tiwari, Ashish; Singh, Santosh Kumar; Gaur, Samir; Jatav, Vijay Singh; Srinivasan, Barthu Parthi; Agarwal, Shyam Sunder

    2012-01-01

    The present study investigated the effect of garlic (Allium sativum Linn.) aqueous extracts on ischemic preconditioning and ischemia-reperfusion induced cardiac injury, as well as adenosine involvement in ischemic preconditioning and garlic extract induced cardioprotection. A model of ischemia-reperfusion injury was established using Langendorff apparatus. Aqueous extract of garlic dose was standardized (0.5%, 0.4%, 0.3%, 0.2%, 0.1%, 0.07%, 0.05%, 0.03%, 0.01%), and the 0.05% dose was found to be the most effective. Higher doses (more than 0.05%) were highly toxic, causing arrhythmia and cardiodepression, whereas the lower doses were ineffective. Garlic exaggerated the cardioprotective effect of ischemic preconditioning. The cardioprotective effect of ischemic preconditioning and garlic cardioprotection was significantly attenuated by theophylline (1,000 µmol/L) and 8-SPT (10 mg/kg, i.p.) and expressed by increased myocardial infarct size, increased LDH level, and reduced nitrite and adenosine levels. These findings suggest that adenosine is involved in the pharmacological and molecular mechanism of garlic induced cardioprotection and mediated by the modulation of nitric oxide. PMID:23554727

  18. Ischemic Preconditioning Mediates Neuroprotection against Ischemia in Mouse Hippocampal CA1 Neurons by Inducing Autophagy

    PubMed Central

    Zhang, Xuebin; Huang, Huiling; Wang, Jin; Wang, Yajing; Tong, Xiaoguang; Wang, Jinhuan; Wu, Jialing

    2015-01-01

    The hippocampal CA1 region is sensitive to hypoxic and ischemic injury but can be protected by ischemic preconditioning (IPC). However, the mechanism through which IPC protects hippocampal CA1 neurons is still under investigation. Additionally, the role of autophagy in determining the fate of hippocampal neurons is unclear. Here, we examined whether IPC induced autophagy to alleviate hippocampal CA1 neuronal death in vitro and in vivo with oxygen glucose deprivation (OGD) and bilateral carotid artery occlusion (BCCAO) models. Survival of hippocampal neurons increased from 51.5% ± 6.3% in the non-IPC group (55 min of OGD) to 77.3% ± 7.9% in the IPC group (15 min of OGD, followed by 55 min of OGD 24 h later). The number of hippocampal CA1 layer neurons increased from 182 ± 26 cells/mm2 in the non-IPC group (20 min of BCCAO) to 278 ± 55 cells/mm2 in the IPC group (1 min × 3 BCCAO, followed by 20 min of BCCAO 24 h later). Akt phosphorylation and microtubule-associated protein light chain 3 (LC3)-II/LC3-I expression were increased in the preconditioning group. Moreover, the protective effects of IPC were abolished only by inhibiting the activity of autophagy, but not by blocking the activation of Akt in vitro. Using in vivo experiments, we found that LC3 expression was upregulated, accompanied by an increase in neuronal survival in hippocampal CA1 neurons in the preconditioning group. The neuroprotective effects of IPC on hippocampal CA1 neurons were completely inhibited by treatment with 3-MA. In contrast, hippocampal CA3 neurons did not show changes in autophagic activity or beneficial effects of IPC. These data suggested that IPC may attenuate ischemic injury in hippocampal CA1 neurons through induction of Akt-independent autophagy. PMID:26325184

  19. Remote ischemic preconditioning and renoprotection: from myth to a novel therapeutic option?

    PubMed

    Gassanov, Natig; Nia, Amir M; Caglayan, Evren; Er, Fikret

    2014-02-01

    There is currently no effective prophylactic regimen available to prevent contrast-induced AKI (CI-AKI), a frequent and life-threatening complication after cardiac catheterization. Therefore, novel treatment strategies are required to decrease CI-AKI incidence and to improve clinical outcomes in these patients. Remote ischemic preconditioning (rIPC), defined as transient brief episodes of ischemia at a remote site before a subsequent prolonged ischemia/reperfusion injury of the target organ, is an adaptational response that protects against ischemic and reperfusion insult. Indeed, several studies demonstrated the tissue-protective effects of rIPC in various target organs, including the kidneys. In this regard, rIPC may offer a novel noninvasive and virtually cost-free treatment strategy for decreasing CI-AKI incidence. This review evaluates the current experimental and clinical evidence for rIPC as a potential renoprotective strategy, and discusses the underlying mechanisms and key areas for future research. PMID:24309187

  20. Indomethacin preconditioning induces ischemic tolerance by modifying zinc availability in the brain.

    PubMed

    Lee, Joo-Yong; Oh, Shin Bi; Hwang, Jung-Jin; Suh, Nayoung; Jo, Dong-Gyu; Kim, Jong S; Koh, Jae-Young

    2015-09-01

    Intracellular zinc overload causes neuronal injury during the course of neurological disorders, whereas mild levels of zinc are beneficial to neurons. Previous reports indicated that non-steroidal anti-inflammatory drugs, including indomethacin and aspirin, can reduce the risk of ischemic stroke. This study found that chronic pretreatment of rats with indomethacin, a non-selective cyclooxygenase inhibitor, provided tolerance to ischemic injuries in an animal model of stroke by eliciting moderate zinc elevation in neurons. Consecutive intraperitoneal injection of indomethacin (3mg/kg/day for 28days) led to modest increases in intraneuronal zinc as well as synaptic zinc content, with no significant stimulation of neuronal death. Furthermore, indomethacin induced the expressions of intracellular zinc homeostatic and neuroprotective proteins, rendering the brain resistant against ischemic damages and improving neurological outcomes. However, administration of a zinc-chelator, N,N,N',N'-tetra(2-picolyl)ethylenediamine (TPEN; 15mg/kg/day), immediately after indomethacin administration eliminated the beneficial actions of the drug. Therefore, indomethacin preconditioning can modulate intracellular zinc availability, contributing to ischemic tolerance in the brain after stroke. PMID:25562658

  1. TARGETED DELETION OF INDUCIBLE HEAT SHOCK PROTEIN 70 ABROGATES THE LATE INFARCT-SPARING EFFECT OF MYOCARDIAL ISCHEMIC PRECONDITIONING

    EPA Science Inventory

    Abstract submitted for 82nd annual meeting of the American Association for Thoracic Surgery, May 4-8, 2002 in Washington D.C.

    Targeted Deletion of Inducible Heat Shock Protein 70 Abrogates the Late Infarct-Sparing Effect of Myocardial Ischemic Preconditioning

    Craig...

  2. Mitogen Activated Protein Kinase Phosphatase-1 (MKP-1) in Retinal Ischemic Preconditioning

    PubMed Central

    Dreixler, John C.; Bratton, Anthony; Du, Eugenie; Shaikh, Afzhal R.; Savoie, Brian; Michael, Alexander; Marcet, Marcus; Roth, Steven

    2011-01-01

    We previously described the phenomenon of retinal ischemic preconditioning (IPC) and we have shown the role of various signaling proteins in the protective pathways, including the mitogen-activated protein kinase p38. In this study we examined the role in IPC of mitogen-activated protein kinase phosphatase-1 (MKP-1), which inactivates p38. Ischemia was produced by elevation of intraocular pressure above systolic arterial blood pressure in adult Wistar rats. Preconditioning was produced by transient retinal ischemia for 5 min, 24 h prior to ischemia. Small interfering RNA (siRNA) to MKP-1 or a control non-silencing siRNA, was injected into the vitreous 6 h prior to IPC. Recovery was assessed by electroretinography (ERG) and histology. The a- and b-waves, and oscillatory potentials (OPs), measured before and 1 week after ischemia, were then normalized relative to pre-ischemic baseline, and corrected for diurnal variation in the normal non-ischemic eye. The P2, or post-photoreceptor component of the ERG (which reflects function of the rod bipolar cells in the inner retina), was derived using the Hood-Birch model. MKP-1 was localized in specific retinal cells using immunohistochemistry; levels of mitogen-activated protein kinases were measured using Western blotting. Injection of siRNA to MKP-1 significantly attenuated the protective effect of IPC as reflected by decreased recovery of the electroretinogram a- and b-waves and the P2 after ischemia. The injection of siRNA to MKP-1 reduced the number of cells in the retinal ganglion cell and outer nuclear layers after IPC and ischemia. Blockade of MKP-1 by siRNA also increased the activation of p38 at 24 h following IPC. MKP-1 siRNA did not alter the levels of phosphorylated jun N-terminal kinase (JNK) or extracellular signal-regulated kinase (ERK) after IPC. The results suggest the involvement of dual-specificity phosphatase MKP-1 in IPC and that MKP-1 is involved in IPC by regulating levels of activated MAPK p38. PMID:21094639

  3. Impact of ischemic preconditioning on ischemia-reperfusion injury of the rat sciatic nerve

    PubMed Central

    Dong, Shuanghai; Cao, Yun; Li, Haoqing; Tian, Jiwei; Yi, Chengqing; Sang, Weilin

    2015-01-01

    The aim of this study was to assess the preventive effects of ischemic preconditioning (IPC) on ischemia-reperfusion (IR) injury in the sciatic nerve of the rat hind limb. This study included two experiments. For Experiment 1, 40 Sprague-Dawley (SD) rats were randomly divided into 4 equal groups that received different IPC treatments prior to IR. Serum concentrations of aspartate aminotransferase (AST), lactate dehydrogenase (LDH), malondialdehyde (MDA), and superoxide dismutase (SOD) were assessed following reperfusion. Furthermore, we tested the electrophysiological response and ultrastructural changes in the ipsilateral sciatic nerve after IR. After determining the best IPC protocol for protection, we performed a second experiment with 30 SD rats randomly divided into 3 equal groups. Each group underwent 1, 2, or 3 IPC cycles before prolonged ischemia and reperfusion. The same analyses as in Experiment 1 were performed. In Experiment 1, the AST, LDH, and MDA concentrations were decreased in all IPC groups compared with the control group. Concentration of these enzymes showed decreases with increasing IPC cycle number in Experiment 2; however, the difference between 2 and 3 cycles of IPC did not reach significance. Conversely, SOD activity increased in the rapid and delayed groups, and with increasing cycles of IPC. The electrophysiological test showed a decrease in amplitude and increase in conduction velocity with increasing IPC cycles. Moreover, ultrastructural damage decreased with increasing IPC cycles. IPC protected against IR injury in the peripheral nerves. This effect was positively correlated with the number of IPC cycles. PMID:26629140

  4. Effect of ischemic preconditioning on P-selectin expression in hepatocytes of rats with cirrhotic ischemia-reperfusion injury

    PubMed Central

    Cheng, Xiang-Dong; Jiang, Xian-Chuan; Liu, Yin-Bing; Peng, Cheng-Hong; Xu, Bin; Peng, Shu-You

    2003-01-01

    AIM: To investigate the effects and mechanisms of ischemic preconditioning (IPC) on the ischemia/reperfusion (I/R) injury of liver cirrhosis in rats and the effect of IPC on P-selectin expression in hepatocytes. METHODS: Forty male SD rats with liver cirrhosis were randomly divided into sham operation group (SO group), ischemia/reperfusion group (I/R group), ischemic preconditioning group (IPC group), L-Arginine preconditioning group (APC group), L-NAME preconditioning group (NPC group), eight rats in each group. Hepatocellular viability was assessed by hepatic adenine nucleotide level and energy charge (EC) determined by HPLC, ALT, AST and LDH in serum measured by auto- biochemical analyzer and bile output. The expression of P-selectin in the liver tissue was analyzed by immunohistochemical technique. Leukocyte count in ischemic hepatic lobe was calculated. RESULTS: At 120 min after reperfusion, the level of ATP and EC in IPC and APC groups was higher than that in I/R group significantly. The increases in AST, ALT and LDH were prevented in IPC and APC groups. The livers produced more bile in IPC group than in I/R group during 120 min after reperfusion (0.101 ± 0.027 vs 0.066 ± 0.027 mL/g liver, P = 0.002). There was a significant difference between APC and I/R groups, (P = 0.001). The leukocyte count in liver tissues significantly increased in I/R group as compared with SO group (P < 0.05). The increase in the leukocyte count was prevented in IPC group. Administration of L-arginine resulted in the same effects as in IPC group. However, inhibition of NO synthesis (NPC group) held back the beneficial effects of preconditioning. Significant promotion of P-selectin expression in hepatocytes in the I/R group was observed compared with the SO group (P < 0.01). IPC or L-arginine attenuated P-selectin expression remarkably (P < 0.01). However, inhibition of NO synthesis enhanced P-selectin expression (P < 0.01). The degree of P-selectin expression was positively correlated with the leukocyte counts infiltrating in liver (r = 0.602, P = 0.000). CONCLUSION: IPC can attenuate the damage induced by I/R in cirrhotic liver and increase the ischemic tolerance of the rats with liver cirrhosis. IPC can abolish I/R induced leukocyte adhesion and infiltration by preventing post-ischemic P-selectin expression in the rats with liver cirrhosis via a NO-initiated pathway. PMID:14562395

  5. Extracellular Adenosine Formation by Ecto-5’-Nucleotidase (CD73) Is No Essential Trigger for Early Phase Ischemic Preconditioning

    PubMed Central

    2015-01-01

    Background Adenosine is a powerful trigger for ischemic preconditioning (IPC). Myocardial ischemia induces intracellular and extracellular ATP degradation to adenosine, which then activates adenosine receptors and elicits cardioprotection. Conventionally extracellular adenosine formation by ecto-5’-nucleotidase (CD73) during ischemia was thought to be negligible compared to the massive intracellular production, but controversial reports in the past demand further evaluation. In this study we evaluated the relevance of ecto-5’-nucleotidase (CD73) for infarct size reduction by ischemic preconditioning in in vitro and in vivo mouse models of myocardial infarction, comparing CD73-/- and wild type (WT) mice. Methods and Results 3x5 minutes of IPC induced equal cardioprotection in isolated saline perfused hearts of wild type (WT) and CD73-/- mice, reducing control infarct sizes after 20 minutes of ischemia and 90 minutes of reperfusion from 46 ± 6.3% (WT) and 56.1 ± 7.6% (CD73-/-) to 26.8 ± 4.7% (WT) and 25.6 ± 4.7% (CD73-/-). Coronary venous adenosine levels measured after IPC stimuli by high-pressure liquid chromatography showed no differences between WT and CD73-/- hearts. Pharmacological preconditioning of WT hearts with adenosine, given at the measured venous concentration, was evenly cardioprotective as conventional IPC. In vivo, 4x5 minutes of IPC reduced control infarct sizes of 45.3 ± 8.9% (WT) and 40.5 ± 8% (CD73-/-) to 26.3 ± 8% (WT) and 22.6 ± 6.6% (CD73-/-) respectively, eliciting again equal cardioprotection. The extent of IPC-induced cardioprotection in male and female mice was identical. Conclusion The infarct size limiting effects of IPC in the mouse heart in vitro and in vivo are not significantly affected by genetic inactivation of CD73. The ecto-5’-nucleotidase derived extracellular formation of adenosine does not contribute substantially to adenosine’s well known cardioprotective effect in early phase ischemic preconditioning. PMID:26261991

  6. Protective effect of ischemic preconditioning on the jejunal graft mucosa injury during cold preservation.

    PubMed

    Jonecova, Zuzana; Toth, Stefan; Maretta, Milan; Ciccocioppo, Rachele; Varga, Jan; Rodrigo, Luis; Kruzliak, Peter

    2015-10-01

    Protection of intestinal graft mucosa during cold preservation is still an unmet need in clinical practice, thus affecting the success of transplantation. The present study investigates the ability of two ischemic preconditioning (IPC) procedures to limit cold preservation injury. Three groups of Sprague-Dawley rats were recruited (n=11 each) as follows: the short IPC (SIPC) performed through 4cycles of mesenteric ischemia of 4min each followed by 10min of reperfusion, the long IPC (LIPC) obtained by 2 ischemic cycles of 12min each followed by 10min of reperfusion, and the control group (C) without IPC. Grafts were then stored in cold histidine-tryptophan-ketoglutarate solution and samples were taken at 0, 3, 6 and 9h lasting preservation. Both IPC groups showed an advanced degree of preservation with delayed development of graft mucosa damage, mainly in the crypt region. At the beginning of preservation, the graft mucosa in both IPC groups showed lower degree of mucosal injury index (MII) by 50% in comparison with C group. Specifically, a significant improvement of MII was observed after 3h of preservation in the LIPC group (p<0.05) in comparison with untreated C grafts. Significant atrophy of the intestinal mucosa in C group was found after 3h of preservation (p<0.01), in SIPC group the progress of atrophy was delayed to 6h (p<0.001), and in LIPC group only moderate decrease in that was found. A parallel increase of laminin expression with the MII rate after 6 and 9h of preservation in comparison with the level at time 0 was observed in all grafts (p<0.001 and p<0.01, respectively). In both IPC groups the apoptotic cell (AC) rate was significantly reduced at the beginning of cold preservation (p<0.05 both). Moreover, in both the SIPC and C groups, the progressive increase in MII rate connected with AC rate decrease was due to a predominance of necrosis. By contrast in the LIPC group, after an increase of nearly 50% in the AC rate at the 3rd hour, its level remained fairly constant during the further 6h of preservation, thus probably preventing necrosis and improving graft viability. PMID:26123930

  7. Accumulation of natural killer cells in ischemic brain tissues and the chemotactic effect of IP-10

    PubMed Central

    2014-01-01

    Background Stroke is accompanied by a distinguished inflammatory reaction that is initiated by the infiltration of immunocytes, expression of cytokines, and other inflammatory mediators. As natural killer cells (NK cells) are a type of cytotoxic lymphocyte critical to the innate immune system, we investigated the mechanism of NK cells-induced brain injuries after cerebral ischemia and the chemotactic effect of IP-10 simultaneously. Methods NK cells infiltration, interferon-gamma (IFN-?) and IP-10 expression were detected by immunohistochemistry, immunofluorescence, PCR and flow cytometry in human and C57/BL6 wild type mouse ischemic brain tissues. The ischemia area was detected via 2,3,5-triphenyltetrazolium chloride staining. CXCR3 mean fluorescence intensity of isolated NK cells was measured by flow cytometry. The neuronal injury made by NK cells was examined via apoptosis experiment. The chemotactic of IP-10 was detected by migration and permeability assays. Results In human ischemic brain tissue, infiltrations of NK cells were observed and reached a peak at 2 to 5 days. In a permanent middle cerebral artery occlusion (pMCAO) model, infiltration of NK cells into the ischemic infarct region reached their highest levels 12 hours after ischemia. IFN-?-positive NK cells and levels of the chemokine IP-10 were also detected within the ischemic region, from 6 hours up to 4 days after pMCAO was performed, and IFN-? levels decreased after NK cells depletion in vivo. Co-culture experiments of neural cells with NK cells also showed that neural necrosis was induced via IFN-?. In parallel experiments with IP-10, the presence of CXCR3 indicates that NK cells were affected by IP-10 via CXCR3, and the effect was dose-dependent. After IP-10 depletion in vivo, NK cells decreased. In migration assays and permeability experiments, disintegration of the blood–brain barrier (BBB) was observed following the addition of NK cells. Moreover, in the presence of IP-10 this injury was aggravated. Conclusions All findings support the hypothesis that NK cells participate in cerebral ischemia and promote neural cells necrosis via IFN-?. Moreover, IP-10 intensifies injury to the BBB by NK cells via CXCR3. PMID:24742325

  8. Impact of ischemic preconditioning on functional sympatholysis during handgrip exercise in humans

    PubMed Central

    Horiuchi, Masahiro; Endo, Junko; Thijssen, Dick H J

    2015-01-01

    Repeated bouts of ischemia followed by reperfusion, known as ischemic preconditioning (IPC), is found to improve exercise performance. As redistribution of blood from the inactive areas to active skeletal muscles during exercise (i.e., functional sympatholysis) is important for exercise performance, we examined the hypothesis that IPC improves functional sympatholysis in healthy, young humans. In a randomized study, 15 healthy young men performed a 10-min resting period, dynamic handgrip exercise at 10% maximal voluntary contraction (MVC), and 25% MVC. This protocol was preceded by IPC (IPC; 4 × 5-min 220-mmHg unilateral occlusion) or a sham intervention (CON; 4 × 5-min 20-mmHg unilateral occlusion). Near-infrared spectroscopy was used to assess changes in oxygenated hemoglobin and myoglobin in skeletal muscle (HbO2 + MbO2) in response to sympathetic activation (via cold pressor test (CPT)) at baseline and during handgrip exercise (at 10% and 25%). In resting conditions, HbO2 + MbO2 significantly decreased during CPT (?11.0 ± 1.0%), which was significantly larger during the IPC-trial (?13.8 ± 1.2%, P = 0.006). During handgrip exercise at 10% MVC, changes in HbO2 + MbO2 in response to the CPT were blunted after IPC (?8.8 ± 1.5%) and CON (?8.3 ± 0.4%, P = 0.593). During handgrip exercise at 25% MVC, HbO2 + MbO2 in response to the CPT increased (2.0 ± 0.4%), whereas this response was significantly larger when preceded by IPC (4.2 ± 0.6%, P = 0.027). Collectively, these results indicate that IPC-induced different vascular changes at rest and during moderate exercise in response to sympathetic activation. This suggests that, in healthy volunteers, exposure to IPC may alter tissue oxygenation during sympathetic stimulation at rest and during exercise. PMID:25713329

  9. Calcium-sensing receptor: a sensor and mediator of ischemic preconditioning in the heart

    PubMed Central

    Murphy, Elizabeth

    2010-01-01

    As a G protein-coupled receptor, the extracellular Ca2+-sensing receptor (CaSR) responds to changes not only in extracellular Ca2+, but also to many other ligands. CaSR has been found to be expressed in the hearts and cardiovascular system. In this study, we confirmed that CaSR is expressed in mouse cardiomyocytes and showed that it is predominantly localized in caveolae. The goal of this study was to investigate whether CaSR plays a cardioprotective role in ischemic preconditioning (IPC). Hearts from C57BL/6J mice (male, 12–16 wk) were perfused in the Langendorff mode and subjected to the following treatments: 1) control perfusion; 2) perfusion with a specific CaSR antagonist, NPS2143; 3) IPC (four cycles of 5 min of global ischemia and 5 min of reperfusion); or 4) perfusion with NPS2143 before and during IPC. Following these treatments, hearts were subjected to 20 min of no-flow global ischemia and 120 min of reperfusion. Compared with control, IPC significantly improved postischemic left ventricular functional recovery and reduced infarct size. Although NPS2143 perfusion alone did not change the hemodynamic function and did not change the extent of postischemic injury, NPS2143 treatment abolished cardioprotection of IPC. Through immunoblot analysis, it was demonstrated that IPC significantly increased the levels of phosphorylated ERK1/2, AKT, and GSK-3?, which were also prevented by NPS2143 treatment. Taken together, the distribution of CaSR in caveolae along with NPS2143-blockade of IPC-induced cardioprotective signaling suggest that the activation of CaSR during IPC is cardioprotective by a process involving caveolae. PMID:20833954

  10. Apolipoprotein A-I Is a Potential Mediator of Remote Ischemic Preconditioning

    PubMed Central

    Hibert, Pierre; Prunier-Mirebeau, Delphine; Beseme, Olivia; Chwastyniak, Maggy; Tamareille, Sophie; Lamon, Delphine; Furber, Alain; Pinet, Florence; Prunier, Fabrice

    2013-01-01

    Background Remote ischemic preconditioning (RIPC) has emerged as an attractive strategy in clinical settings. Despite convincing evidence of the critical role played by circulating humoral mediators, their actual identities remain unknown. In this study, we aimed to identify RIPC-induced humoral mediators using a proteomic approach. Methods and Results Rats were exposed to 10-min limb ischemia followed by 5- (RIPC 5?) or 10-min (RIPC 10?) reperfusion prior to blood sampling. The control group only underwent blood sampling. Plasma samples were analyzed using surface-enhanced laser desorption and ionization - time of flight - mass spectrometry (SELDI-TOF-MS). Three protein peaks were selected for their significant increase in RIPC 10?. They were identified and confirmed as apolipoprotein A-I (ApoA-I). Additional rats were exposed to myocardial ischemia-reperfusion (I/R) and assigned to one of the following groups RIPC+myocardial infarction (MI) (10-min limb ischemia followed by 10-min reperfusion initiated 20 minutes prior to myocardial I/R), ApoA-I+MI (10 mg/kg ApoA-I injection 10 minutes before myocardial I/R), and MI (no further intervention). In comparison with untreated MI rats, RIPC reduced infarct size (52.2±3.7% in RIPC+MI vs. 64.9±2.6% in MI; p<0.05). Similarly, ApoA-I injection decreased infarct size (50.9±3.8%; p<0.05 vs. MI). Conclusions RIPC was associated with a plasmatic increase in ApoA-I. Furthermore, ApoA-I injection before myocardial I/R recapitulated the cardioprotection offered by RIPC in rats. This data suggests that ApoA-I may be a protective blood-borne factor involved in the RIPC mechanism. PMID:24155931

  11. Effects of ischemic preconditioning on maximal constant-load cycling performance.

    PubMed

    Cruz, Rogério Santos de Oliveira; de Aguiar, Rafael Alves; Turnes, Tiago; Pereira, Kayo Leonardo; Caputo, Fabrizio

    2015-11-01

    This study investigated the effects of ischemic preconditioning (IPC) on the ratings of perceived exertion (RPE), surface electromyography, and pulmonary oxygen uptake (V?o2) onset kinetics during cycling until exhaustion at the peak power output attained during an incremental test. A group of 12 recreationally trained cyclists volunteered for this study. After determination of peak power output during an incremental test, they were randomly subjected on different days to a performance protocol preceded by intermittent bilateral cuff pressure inflation to 220 mmHg (IPC) or 20 mmHg (control). To increase data reliability, the performance visits were replicated, also in a random manner. There was an 8.0% improvement in performance after IPC (control: 303 s, IPC 327 s, factor SDs of ×/÷1.13, P = 0.01). This change was followed by a 2.9% increase in peak V?o2 (control: 3.95 l/min, IPC: 4.06 l/min, factor SDs of ×/÷1.15, P = 0.04), owing to a higher amplitude of the slow component of the V?o2 kinetics (control: 0.45 l/min, IPC: 0.63 l/min, factor SDs of ×/÷2.21, P = 0.05). There was also an attenuation in the rate of increase in RPE (P = 0.01) and a progressive increase in the myoelectrical activity of the vastus lateralis muscle (P = 0.04). Furthermore, the changes in peak V?o2 (r = 0.73, P = 0.007) and the amplitude of the slow component (r = 0.79, P = 0.002) largely correlated with performance improvement. These findings provide a link between improved aerobic metabolism and enhanced severe-intensity cycling performance after IPC. Furthermore, the delayed exhaustion after IPC under lower RPE and higher skeletal muscle activation suggest they have a role on the ergogenic effects of IPC on endurance performance. PMID:26359484

  12. Electroacupuncture preconditioning attenuates ischemic brain injury by activation of the adenosine monophosphate-activated protein kinase signaling pathway

    PubMed Central

    Ran, Qiang-qiang; Chen, Huai-long; Liu, Yan-li; Yu, Hai-xia; Shi, Fei; Wang, Ming-shan

    2015-01-01

    Electroacupuncture has therapeutic effects on ischemic brain injury, but its mechanism is still poorly understood. In this study, mice were stimulated by electroacupuncture at the Baihui (GV20) acupoint for 30 minutes at 1 mA and 2/15 Hz for 5 consecutive days. A cerebral ischemia model was established by ligating the bilateral common carotid artery for 15 minutes. At 72 hours after injury, neuronal injury in the mouse hippocampus had lessened, and the number of terminal deoxynucleotide transferase-mediated dUTP nick-end labeling-positive cells reduced after electroacupuncture treatment. Moreover, expression of adenosine monophosphate-activated protein kinase ? (AMPK?) and phosphorylated AMPK? was up-regulated. Intraperitoneal injection of the AMPK antagonist, compound C, suppressed this phenomenon. Our findings suggest that electroacupuncture preconditioning alleviates ischemic brain injury via AMPK activation. PMID:26330828

  13. The endoplasmic reticulum stress inhibitor salubrinal inhibits the activation of autophagy and neuroprotection induced by brain ischemic preconditioning

    PubMed Central

    Gao, Bo; Zhang, Xiang-yang; Han, Rong; Zhang, Tong-tong; Chen, Cheng; Qin, Zheng-hong; Sheng, Rui

    2013-01-01

    Aim: To investigate whether endoplasmic reticulum (ER) stress participates in the neuroprotective effects of ischemic preconditioning (IPC)-induced neuroprotection and autophagy activation in rat brains. Methods: The right middle cerebral artery in SD rats was occluded for 10 min to induce focal cerebral IPC, and was occluded permanently 24 h later to induce permanent focal ischemia (PFI). ER stress inhibitor salubrinal (SAL) was injected via intracerebral ventricle infusion 10 min before the onset of IPC. Infarct volume and motor behavior deficits were examined after the ischemic insult. The protein levels of LC3, p62, HSP70, glucose-regulated protein 78 (GRP 78), p-eIF2? and caspase-12 in the ipsilateral cortex were analyzed using immunoblotting. LC3 expression pattern in the sections of ipsilateral cortex was observed with immunofluorescence. Results: Pretreatment with SAL (150 pmol) abolished the neuroprotective effects of IPC, as evidenced by the significant increases in mortality, infarct volume and motor deficits after PFI. At the molecular levels, pretreatment with SAL (150 pmol) significantly increased p-eIF2? level, and decreased GRP78 level after PFI, suggesting that SAL effectively inhibited ER stress in the cortex. Furthermore, the pretreatment with SAL blocked the IPC-induced upregulation of LC3-II and downregulation of p62 in the cortex, thus inhibiting the activation of autophagy. Moreover,SAL blocked the upregulation of HSP70, but significantly increased the cleaved caspase-12 level, thus promoting ER stress-dependent apoptotic signaling in the cortex. Conclusion: ER stress-induced autophagy might contribute to the neuroprotective effect of brain ischemic preconditioning. PMID:23603983

  14. Ischemic preconditioning protects hippocampal pyramidal neurons from transient ischemic injury via the attenuation of oxidative damage through upregulating heme oxygenase-1.

    PubMed

    Lee, Jae-Chul; Kim, In Hye; Park, Joon Ha; Ahn, Ji Hyeon; Cho, Jeong-Hwi; Cho, Geum-Sil; Tae, Hyun-Jin; Chen, Bai Hui; Yan, Bing Chun; Yoo, Ki-Yeon; Choi, Jung Hoon; Lee, Choong Hyun; Hwang, In Koo; Cho, Jun Hwi; Kwon, Young-Guen; Kim, Young-Myeong; Won, Moo-Ho

    2015-02-01

    Ischemic preconditioning (IPC) provides neuroprotection against subsequent severe ischemic injury by activating specific mechanisms. In this study, we tested the hypothesis that IPC attenuates postischemic neuronal death via heme oxygenase-1 (HO-1). Animals used in this study were randomly assigned to 4 groups; sham-operated group, ischemia-operated group, IPC plus (+) sham-operated group and IPC+ischemia-operated group. IPC was induced by subjecting gerbils to 2min of ischemia followed by 1 day of recovery. A significant loss of neurons was observed in pyramidal neurons of the hippocampal CA1 region (CA1) in the ischemia-operated groups at 5 days postischemia. In the IPC+ischemia-operated groups, CA1 pyramidal neurons were well protected. The level of HO-1 protein and its activity increased significantly in the CA1 of the IPC+sham-operated group, and the level and activity was maintained in all the time after ischemia-reperfusion compared with the ischemia-operated groups. HO-1 immunoreactivity was induced in the CA1 pyramidal neurons in both IPC+sham-operated- and IPC+ischemia-operated groups. We also found that levels or immunoreactivities of superoxide anion, 8-hydroxy-2'-deoxyguanosine and 4-hydroxy-2-nonenal were significantly decreased in the CA1 of both IPC+sham-operated- and IPC+ischemia-operated groups. Whereas, treatment with zinc protoporphyrin IX (a HO-1 inhibitor) into the IPC+ischemia-operated groups did not preserve the IPC-mediated increase of HO-1 and lost beneficial effects of IPC by inhibiting ischemia-induced DNA damage and lipid peroxidation. In brief, IPC protects CA1 pyramidal neurons from ischemic injury by upregulating HO-1, and we suggest that the enhancement of HO-1 expression by IPC may be a legitimate strategy for a therapeutic intervention of cerebral ischemic damage. PMID:25483558

  15. HSP70.1 AND -70.3 ARE REQUIRED FOR LATE-PHASE PROTECTION INDUCED BY ISCHEMIC PRECONDITIONING OF MOUSE HEARTS

    EPA Science Inventory

    Heat-Shock Proteins 70.1 and 70.3 Are Required for Late-phase Protection
    Induced by Ischemic Preconditioning of the Mouse Heart
    Craig R. Hampton 1 , Akira Shimamoto 1 , Christine L. Rothnie 1 , Jeaneatte Griscavage-Ennis 1 ,
    Albert Chong 1 , David J. Dix 2 , Edward D. Ve...

  16. Determinants of the Efficacy of Cardiac Ischemic Preconditioning: A Systematic Review and Meta-Analysis of Animal Studies

    PubMed Central

    Wever, Kimberley E.; Hooijmans, Carlijn R.; Riksen, Niels P.; Sterenborg, Thomas B.; Sena, Emily S.; Ritskes-Hoitinga, Merel; Warlé, Michiel C.

    2015-01-01

    Background Ischemic preconditioning (IPC) of the heart is a protective strategy in which a brief ischemic stimulus immediately before a lethal ischemic episode potently limits infarct size. Although very promising in animal models of myocardial infarction, IPC has not yet been successfully translated to benefit for patients. Objective To appraise all preclinical evidence on IPC for myocardial infarction and identify factors hampering translation. Methods and results Using systematic review and meta-analysis, we identified 503 animal studies reporting infarct size data from 785 comparisons between IPC-treated and control animals. Overall, IPC reduced myocardial infarction by 24.6% [95%CI 23.5, 25.6]. Subgroup analysis showed that IPC efficacy was reduced in comorbid animals and non-rodents. Efficacy was highest in studies using 2–3 IPC cycles applied <45 minutes before myocardial infarction. Local and remote IPC were equally effective. Reporting of study quality indicators was low: randomization, blinding and a sample size calculation were reported in 49%, 11% and 2% of publications, respectively. Conclusions Translation of IPC to the clinical setting may be hampered by the observed differences between the animals used in preclinical IPC studies and the patient population, regarding comorbidity, sex and age. Furthermore, the IPC protocols currently used in clinical trials could be optimized in terms of timing and the number of ischemic cycles applied. In order to inform future clinical trials successfully, future preclinical studies on IPC should aim to maximize both internal and external validity, since poor methodological quality may limit the value of the preclinical evidence. PMID:26580958

  17. Renoprotective Mechanism of Remote Ischemic Preconditioning Based on Transcriptomic Analysis in a Porcine Renal Ischemia Reperfusion Injury Model

    PubMed Central

    Kim, Sook Young; Cho, Young In; Lee, Kwang Suk; Kim, Kwang Hyun; Yang, Seung Choul; Han, Woong Kyu

    2015-01-01

    Ischemic preconditioning (IPC) is a well-known phenomenon in which tissues are exposed to a brief period of ischemia prior to a longer ischemic event. This technique produces tissue tolerance to ischemia reperfusion injury (IRI). Currently, IPC’s mechanism of action is poorly understood. Using a porcine single kidney model, we performed remote IPC with renal IRI and evaluated the IPC mechanism of action. Following left nephrectomy, 15 female Yorkshire pigs were divided into three groups: no IPC and 90 minutes of warm ischemia (control), remote IPC immediately followed by 90 minutes of warm ischemia (rIPCe), and remote IPC with 90 minutes of warm ischemia performed 24 hours later (rIPCl). Differential gene expression analysis was performed using a porcine-specific microarray. The microarray analysis of porcine renal tissues identified 1,053 differentially expressed probes in preconditioned pigs. Among these, 179 genes had altered expression in both the rIPCe and rIPCl groups. The genes were largely related to oxidation reduction, apoptosis, and inflammatory response. In the rIPCl group, an additional 848 genes had altered expression levels. These genes were primarily related to immune response and inflammation, including those coding for cytokines and cytokine receptors and those that play roles in the complement system and coagulation cascade. In the complement system, the membrane attack complex was determined to be sublytic, because it colocalized with phosphorylated extracellular signal-regulated kinase. Furthermore, alpha 2 macroglobulin, tissue plasminogen activator, uterine plasmin trypsin inhibitor, and arginase-1 mRNA levels were elevated in the rIPCl group. These findings indicate that remote IPC produces renoprotective effects through multiple mechanisms, and these effects develop over a long timeframe rather than immediately following IPC. PMID:26489007

  18. Modifications in Rat Plasma Proteome after Remote Ischemic Preconditioning (RIPC) Stimulus: Identification by a SELDI-TOF-MS Approach

    PubMed Central

    Hibert, Pierre; Prunier-Mirebeau, Delphine; Beseme, Olivia; Chwastyniak, Maggy; Tamareille, Sophie

    2014-01-01

    Remote ischemic preconditioning’s (RIPC) ability to render the myocardium resistant to subsequent prolonged ischemia is now clearly established in different species, including humans. Strong evidence suggests that circulating humoral mediators play a key role in signal transduction, but their identities still need to be established. Our study sought to identify potential circulating RIPC mediators using a proteomic approach. Rats were exposed to 10-min limb ischemia followed by 5- (RIPC 5?) or 10-min (RIPC 10?) reperfusion prior to blood sampling. The control group only underwent blood sampling. Plasma samples were isolated for proteomic analysis using surface-enhanced laser desorption and ionization - time of flight - mass spectrometry (SELDI-TOF-MS). A total of seven proteins, including haptoglobin and transthyretin, were detected as up- or down-regulated in response to RIPC. These proteins had previously been identified as associated with organ protection, anti-inflammation, and various cellular and molecular responses to ischemia. In conclusion, this study indicates that RIPC results in significant modulations of plasma proteome. PMID:24454915

  19. AdVEGF-All6A+ Preconditioning of Murine Ischemic Skin Flaps Is Comparable to Surgical Delay

    PubMed Central

    Gersch, Robert P.; Fourman, Mitchell S.; Phillips, Brett T.; Nasser, Ahmed; McClain, Steve A.; Khan, Sami U.; Dagum, Alexander B.

    2015-01-01

    Background: Surgical flap delay is commonly used in preconditioning reconstructive flaps to prevent necrosis. However, staged procedures are not ideal. Pharmacologic up-regulation of angiogenic and arteriogenic factors before flap elevation poses a nonsurgical approach to improve flap survival. Methods: Male Sprague Dawley rats were divided into control (n = 16), surgical delay (Delay), AdNull, AdEgr-1, and AdVEGF (n ? 9/group) groups. Delay rats had a 9 cm × 3 cm cranial based pedicle skin flap incised 10 days prior to elevation. Adenoviral groups received 28 intradermal injections (109 pu/animal total) throughout the distal two thirds of the flap 1 week prior to elevation. At postoperative day (POD) 0 flaps were elevated and silicone sheeting was placed between flap and wound bed. Perfusion analysis in arbitrary perfusion units of the ischemic middle third of the flap using laser Doppler imaging was conducted preoperatively and on POD 0, 3, and 7. Clinical and histopathologic assessments of the skin flaps were performed on POD 7. Results: AdVEGF (50.8 ± 10.9 APU) and AdEgr-1 (39.3 ± 10.6 APU) perfusion levels were significantly higher than controls (16.5 ± 4.2 APU) on POD 7. Delay models were equivalent to controls (25.9 ± 6.8 APU). AdVEGF and Delay animals showed significantly more viable surface area on POD 7 (14.4 ± 1.3 cm2, P < 0.01 and 12.4 ± 1.2 cm2, P < 0.05, respectively) compared with Controls (8.7 ± 0.7 cm2). Conclusions: AdVEGF preconditioning resulted in flap survival comparable to surgical delay. Adenoviral preconditioning maintained perfusion levels postoperatively while surgical delay did not. PMID:26495207

  20. p63 Expression in the Gerbil Hippocampus Following Transient Ischemia and Effect of Ischemic Preconditioning on p63 Expression in the Ischemic Hippocampus.

    PubMed

    Lee, Jae-Chul; Cho, Geum-Sil; Kim, In Hye; Park, Joon Ha; Cho, Jeong-Hwi; Ahn, Ji Hyeon; Bae, Eun Joo; Ahn, Ji Yun; Park, Chan Woo; Cho, Jun Hwi; Kim, Young-Myeong; Won, Moo-Ho; Lee, Hui Young

    2015-05-01

    p63 is a transcription factor of p53 gene family, which are involved in development, differentiation and cell response to stress; however, its roles in ischemic preconditioning (IPC) in the brain are not clear. In the present study, we investigated the effect of IPC on p63 immunoreactivity caused by 5 min of transient cerebral ischemia in gerbils. IPC was induced by subjecting the gerbils to 2 min of transie ischemia 1 day prior to 5 min of transient ischemia. The animals were randomly assigned to four groups (sham-operated-group, ischemia-operated-group, IPC plus (+)-sham-operated-group and IPC + ischemia-operated-group). The number of viable neurons in the stratum pyramidale of the hippocampal CA1 region (CA1) was significantly increased by IPC + ischemia-operated-group compared with that in the ischemia-operated-group 5 days after ischemic insult. We found that strong p63 immunoreactivity was detected in the CA1 pyramidal neurons in the sham-operated-group, and the immunoreactivity was decreased with time after ischemia-reperfusion. In addition, strong p63 immunoreactivity was newly expressed in microglial cells of the CA1 region from 2 days after ischemia-reperfusion. In all the IPC + sham-operated-groups, p63 immunoreactivity in the CA1 pyramidal neurons was similar to that in the sham-operated-group, and the immunoreactivity was well maintained in the IPC + ischemia-operated-groups after cerebral ischemia. In brief, our present findings show that IPC dramatically protected the reduction of p63 immunoreactivity in the pyramidal neurons of the CA1 region after ischemia-reperfusion, and this result suggests that the expression of p63 may be necessary for neurons to survive after transient cerebral ischemia. PMID:25777256

  1. Hypoxia-inducible factor 1 transcriptional activity in endothelial cells is required for acute phase cardioprotection induced by ischemic preconditioning

    PubMed Central

    Sarkar, Kakali; Cai, Zheqing; Gupta, Rigu; Parajuli, Nirmal; Fox-Talbot, Karen; Darshan, Medha S.; Gonzalez, Frank J.; Semenza, Gregg L.

    2012-01-01

    Infarction occurs when myocardial perfusion is interrupted for prolonged periods of time. Short episodes of ischemia and reperfusion protect against tissue injury when the heart is subjected to a subsequent prolonged ischemic episode, a phenomenon known as ischemic preconditioning (IPC). Hypoxia-inducible factor 1 (HIF-1) is a transcription factor that mediates adaptive responses to hypoxia/ischemia and is required for IPC. In this study, we performed a cellular and molecular characterization of the role of HIF-1 in IPC. We analyzed mice with knockout of HIF-1? or HIF-1? in Tie2+ lineage cells, which include bone marrow (BM) and vascular endothelial cells, compared with control littermates. Hearts were subjected to 30 min of ischemia and 120 min of reperfusion, either as ex vivo Langendorff preparations or by in situ occlusion of the left anterior descending artery. The IPC stimulus consisted of two cycles of 5-min ischemia and 5-min reperfusion. Mice lacking HIF-1? or HIF-1? in Tie2+ lineage cells showed complete absence of protection induced by IPC, whereas significant protection was induced by adenosine infusion. Treatment of mice with a HIF-1 inhibitor (digoxin or acriflavine) 4 h before Langendorff perfusion resulted in loss of IPC, as did administration of acriflavine directly into the perfusate immediately before IPC. We conclude that HIF-1 activity in endothelial cells is required for acute IPC. Expression and dimerization of the HIF-1? and HIF-1? subunits is required, suggesting that the heterodimer is functioning as a transcriptional activator, despite the acute nature of the response. PMID:22699503

  2. Hypoxia-inducible factor 1 transcriptional activity in endothelial cells is required for acute phase cardioprotection induced by ischemic preconditioning.

    PubMed

    Sarkar, Kakali; Cai, Zheqing; Gupta, Rigu; Parajuli, Nirmal; Fox-Talbot, Karen; Darshan, Medha S; Gonzalez, Frank J; Semenza, Gregg L

    2012-06-26

    Infarction occurs when myocardial perfusion is interrupted for prolonged periods of time. Short episodes of ischemia and reperfusion protect against tissue injury when the heart is subjected to a subsequent prolonged ischemic episode, a phenomenon known as ischemic preconditioning (IPC). Hypoxia-inducible factor 1 (HIF-1) is a transcription factor that mediates adaptive responses to hypoxia/ischemia and is required for IPC. In this study, we performed a cellular and molecular characterization of the role of HIF-1 in IPC. We analyzed mice with knockout of HIF-1? or HIF-1? in Tie2(+) lineage cells, which include bone marrow (BM) and vascular endothelial cells, compared with control littermates. Hearts were subjected to 30 min of ischemia and 120 min of reperfusion, either as ex vivo Langendorff preparations or by in situ occlusion of the left anterior descending artery. The IPC stimulus consisted of two cycles of 5-min ischemia and 5-min reperfusion. Mice lacking HIF-1? or HIF-1? in Tie2(+) lineage cells showed complete absence of protection induced by IPC, whereas significant protection was induced by adenosine infusion. Treatment of mice with a HIF-1 inhibitor (digoxin or acriflavine) 4 h before Langendorff perfusion resulted in loss of IPC, as did administration of acriflavine directly into the perfusate immediately before IPC. We conclude that HIF-1 activity in endothelial cells is required for acute IPC. Expression and dimerization of the HIF-1? and HIF-1? subunits is required, suggesting that the heterodimer is functioning as a transcriptional activator, despite the acute nature of the response. PMID:22699503

  3. Delayed intranasal delivery of hypoxic-preconditioned bone marrow mesenchymal stem cells enhanced cell homing and therapeutic benefits after ischemic stroke in mice.

    PubMed

    Wei, Ning; Yu, Shan Ping; Gu, Xiaohuan; Taylor, Tammi M; Song, Denise; Liu, Xin-Feng; Wei, Ling

    2013-01-01

    Stem cell transplantation therapy has emerged as a potential treatment for ischemic stroke and other neurodegenerative diseases. Effective delivery of exogenous cells and homing of these cells to the lesion region, however, have been challenging issues that hinder the efficacy and efficiency of cell-based therapy. In the present investigation, we tested a delayed treatment of noninvasive and brain-targeted intranasal delivery of bone marrow mesenchymal stem cells (BMSCs) in a mouse focal cerebral ischemia model. The investigation tested the feasibility and effectiveness of intranasal delivery of BMSCs to the ischemic cortex. Hypoxia preconditioning (HP) of BMSCs was performed before transplantation in order to promote their survival, migration, and homing to the ischemic brain region after intranasal transplantation. Hoechst dye-labeled normoxic- or hypoxic-pretreated BMSCs (1 × 10(6) cells/animal) were delivered intranasally 24 h after stroke. Cells reached the ischemic cortex and deposited outside of vasculatures as early as 1.5 h after administration. HP-treated BMSCs (HP-BMSCs) showed a higher level of expression of proteins associated with migration, including CXC chemokine receptor type 4 (CXCR4), matrix metalloproteinase 2 (MMP-2), and MMP-9. HP-BMSCs exhibited enhanced migratory capacities in vitro and dramatically enhanced homing efficiency to the infarct cortex when compared with normoxic cultured BMSCs (N-BMSCs). Three days after transplantation and 4 days after stroke, both N-BMSCs and HP-BMSCs decreased cell death in the peri-infarct region; significant neuroprotection of reduced infarct volume was seen in mice that received HP-BMSCs. In adhesive removal test of sensorimotor functional assay performed 3 days after transplantation, HP-BMSC-treated mice performed significantly better than N-BMSC- and vehicle-treated animals. These data suggest that delayed intranasal administration of stem cells is feasible in the treatment of stroke and hypoxic preconditioning of transplanted cells, significantly enhances cell's homing to the ischemic region, and optimizes the therapeutic efficacy. PMID:23031629

  4. Remote ischemic preconditioning with a specialized protocol activates the non-neuronal cardiac cholinergic system and increases ATP content in the heart.

    PubMed

    Oikawa, Shino; Mano, Asuka; Takahashi, Rina; Kakinuma, Yoshihiko

    2015-11-01

    Ischemic preconditioning (IPC) renders the targeted organ resistant to prolonged ischemic insults, leading to organoprotection. Among several means to achieve IPC, we reported that remote ischemic preconditioning (RIPC) activates the non-neuronal cardiac cholinergic system (NNCCS) to accelerate de novo ACh synthesis in cardiomyocytes. In the current study, we aimed to optimize a specific protocol to most efficiently activate NNCCS using RIPC. In this study, we elucidated that the protocol with 3min of ischemia repeated three times increased cardiac ChAT expression (139.2±0.4%; P<0.05) as well as ACh (14.2±2.0×10(-8)M; P<0.05) and ATP content (2.13±0.19?mol/g tissue; P<0.05) in the heart. Moreover, in the specific protocol, several characteristic responses against energy starvation and for obtaining adequate energy were observed; therefore, it is suggested that RIPC evokes a robust response by the heart to activate NNCCS through the modification of energy metabolism. PMID:26072685

  5. Monocarboxylate transporter 4 plays a significant role in the neuroprotective mechanism of ischemic preconditioning in transient cerebral ischemia

    PubMed Central

    Hong, Seongkweon; Ahn, Ji Yun; Cho, Geum-Sil; Kim, In Hye; Cho, Jeong Hwi; Ahn, Ji Hyeon; Park, Joon Ha; Won, Moo-Ho; Chen, Bai Hui; Shin, Bich-Na; Tae, Hyun-Jin; Park, Seung Min; Cho, Jun Hwi; Choi, Soo Young; Lee, Jae-Chul

    2015-01-01

    Monocarboxylate transporters (MCTs), which carry monocarboxylates such as lactate across biological membranes, have been associated with cerebral ischemia/reperfusion process. In this study, we studied the effect of ischemic preconditioning (IPC) on MCT4 immunoreactivity after 5 minutes of transient cerebral ischemia in the gerbil. Animals were randomly designated to four groups (sham-operated group, ischemia only group, IPC + sham-operated group and IPC + ischemia group). A serious loss of neuron was found in the stratum pyramidale of the hippocampal CA1 region (CA1), not CA2/3, of the ischemia-only group at 5 days post-ischemia; however, in the IPC + ischemia groups, neurons in the stratum pyramidale of the CA1 were well protected. Weak MCT4 immunoreactivity was found in the stratum pyramidale of the CA1 in the sham-operated group. MCT4 immunoreactivity in the stratum pyramidale began to decrease at 2 days post-ischemia and was hardly detected at 5 days post-ischemia; at this time point, MCT4 immunoreactivity was newly expressed in astrocytes. In the IPC + sham-operated group, MCT4 immunoreactivity in the stratum pyramidale of the CA1 was increased compared with the sham-operated group, and, in the IPC + ischemia group, MCT4 immunoreactivity was also increased in the stratum pyramidale compared with the ischemia only group. Briefly, present findings show that IPC apparently protected CA1 pyramidal neurons and increased or maintained MCT4 expression in the stratum pyramidale of the CA1 after transient cerebral ischemia. Our findings suggest that MCT4 appears to play a significant role in the neuroprotective mechanism of IPC in the gerbil with transient cerebral ischemia.

  6. Effect of Remote Ischemic Preconditioning on Phosphorylated Protein Signaling in Children Undergoing Tetralogy of Fallot Repair: A Randomized Controlled Trial

    PubMed Central

    Pepe, Salvatore; Liaw, Norman Y.; Hepponstall, Michele; Sheeran, Freya L.; Yong, Matthew S.; d'Udekem, Yves; Cheung, Michael M.; Konstantinov, Igor E.

    2013-01-01

    Background Our previous randomized controlled trial demonstrated cardiorespiratory protection by remote ischemic preconditioning (RIPC) in children before cardiac surgery. However, the impact of RIPC on myocardial prosurvival intracellular signaling remains unknown in cyanosis. RIPC may augment phosphorylated protein signaling in myocardium and circulating leukocytes during tetralogy of Fallot (ToF) repair. Methods and Results Children (n=40) undergoing ToF repair were double?blind randomized to RIPC (n=11 boys, 9 girls) or control (sham RIPC: n=9 boys, 11 girls). Blood samples were taken before, immediately after, and 24 hours after cardiopulmonary bypass. Resected right ventricular outflow tract muscle and leukocytes were processed for protein expression and mitochondrial respiration. There was no difference in age (7.1±3.4 versus 7.1±3.4 months), weight (7.7±1.8 versus 7.5±1.9 kg), or bypass or aortic cross?clamp times between the groups (control versus RIPC, mean±SD). No differences were seen between the groups for an increase in the ratio of phosphorylated to total protein for protein kinase B, p38 mitogen activated protein kinase, signal transducer and activator of transcription 3, glycogen synthase kinase 3?, heat shock protein 27, Connexin43, or markers associated with promotion of necrosis (serum cardiac troponin I), apoptosis (Bax, Bcl?2), and autophagy (Parkin, Beclin?1, LC3B). A high proportion of total proteins were in phosphorylated form in control and RIPC myocardium. In leukocytes, mitochondrial respiration and assessed protein levels did not differ between groups. Conclusions In patients with cyanotic heart disease, a high proportion of proteins are in phosphorylated form. RIPC does not further enhance phosphorylated protein signaling in myocardium or circulating leukocytes in children undergoing ToF repair. Clinical Trial Registration URL: (http://www.anzctr.org.au/trial_view.aspx?id=335613. Unique identifier: Australian New Zealand Clinical Trials Registry number ACTRN12610000496011. PMID:23666460

  7. Dynamic Changes in DNA Methylation in Ischemic Tolerance

    PubMed Central

    Meller, Robert; Pearson, Andrea; Simon, Roger P.

    2015-01-01

    Epigenetic mediators of gene expression are hypothesized to regulate transcriptomic responses to preconditioning ischemia and ischemic tolerance. Here, we utilized a methyl-DNA enrichment protocol and sequencing (ChIP-seq) to identify patterns of DNA methylation in an established model of ischemic tolerance in neuronal cultures (oxygen and glucose deprivation: OGD). We observed an overall decrease in global DNA methylation at 4?h following preconditioning ischemia (30?min OGD), harmful ischemia (120?min OGD), and in ischemic tolerant neuronal cultures (30?min OGD, 24?h recovery, 120?min OGD). We detected a smaller cohort of hypermethylated regions following ischemic conditions, which were further analyzed revealing differential chromosomal localization of methylation, and a differential concentration of methylation on genomic regions. Together, these data show that the temporal profiles of DNA methylation with respect to chromatin hyper- and hypo-methylation following various ischemic conditions are highly dynamic, and may reveal novel targets for neuroprotection. PMID:26029158

  8. Remote ischemic preconditioning mitigates myocardial and neurological dysfunction via K(ATP) channel activation in a rat model of hemorrhagic shock.

    PubMed

    Hu, Xianwen; Yang, Zhengfei; Yang, Min; Qian, Jie; Cahoon, Jena; Xu, Jiefeng; Sun, Shijie; Tang, Wanchun

    2014-09-01

    Severe hemorrhagic shock and resuscitation is a state of global body ischemia and reperfusion that causes myocardial and cerebral dysfunction. We investigated whether remote ischemic preconditioning (RIPC) would reduce myocardial and cerebral ischemia and reperfusion injuries after hemorrhagic shock as the result of the K(ATP) channel activation. Twenty-one male rats were randomized into three groups: RIPC, RIPC with K(ATP) channel blocker, and control. Remote ischemic preconditioning was induced by four cycles of 5 min of limb ischemia followed by reperfusion for 5 min. Hemorrhagic shock was induced by removing 50% of the estimated total blood volume during an interval of 1 h. Thirty minutes after the completion of bleeding, the animals were reinfused with shed blood during the ensuing 30 min. The animals were monitored for 2 h and observed for an additional 72 h. Myocardial function was measured by echocardiography, and sublingual microcirculation was measured by a sidestream dark-field imaging device at baseline, 1 h after bleeding, 30 min after the completion of bleeding, 30 min after reinfusion, and hourly intervals thereafter. The survival and neurological function were evaluated at 12, 24, 48, and 72 h after reinfusion. At 2 h after reinfusion, ejection fraction and myocardial performance index were significantly better in the RIPC group than in the control group (P < 0.01). The sublingual microvascular flow index and perfused vessel density were significantly greater after reinfusion in the RIPC group than that in the control group (P < 0.01). The duration of survival was significantly longer, and neurological deficit score was significantly better in the RIPC group than the control animals (P < 0.01). Pretreatment with the K(ATP) channel blocker (glibenclamide) completely abolished the myocardial and cerebral protective effects of RIPC. We demonstrate, for the first time, that after severe hemorrhagic shock and resuscitation, RIPC mitigated myocardial and neurological dysfunction with improved survival by activation of the K(ATP) channel. PMID:25122082

  9. Ischemic preconditioning protects neurons from damage and maintains the immunoreactivity of kynurenic acid in the gerbil hippocampal CA1 region following transient cerebral ischemia

    PubMed Central

    LEE, JAE-CHUL; TAE, HYUN-JIN; CHO, GEUM-SIL; KIM, IN HYE; AHN, JI HYEON; PARK, JOON HA; CHEN, BAI HUI; CHO, JEONG-HWI; SHIN, BICH NA; CHO, JUN HWI; BAE, EUN JOO; PARK, JINSEU; KIM, YOUNG-MYEONG; CHOI, SOO YOUNG; WON, MOO-HO

    2015-01-01

    Pyramidal neurons in region I of hippocampus proper (CA1) are particularly vulnerable to excitotoxic processes following transient forebrain ischemia. Kynurenic acid (KYNA) is a small molecule derived from tryptophan when this amino acid is metabolized through the kynurenine pathway. In the present study, we examined the effects of ischemic preconditioning (IPC) on the immunoreactivity and protein levels of KYNA following 5 min of transient forebrain ischemia in gerbils. The animals were randomly assigned to 4 groups (sham-operated group, ischemia-operated group, IPC + sham-operated group and IPC + ischemia-operated group). IPC was induced by subjecting the gerbils to 2 min of ischemia followed by 1 day of recovery. In the ischemia-operated group, we observed a significant loss of pyramidal neurons in the CA1 stratum pyramidale (SP) at 5 days post-ischemia; however, in the IPC + ischemia-operated group, the pyramidal neurons were well protected. KYNA immunoreactivity in the SP of the ischemia-operated group was significantly altered following ischemia-reperfusion and was very low 5 days following ischemia-reperfusion. In the IPC + ischemia-operated group, however, KYNA immunoreactivity was constitutively detected in the SP of the CA1 region after the ischemic insult. We also found that the alteration pattern of the KYNA protein level in the CA1 region following ischemia was generally similar to the immunohistochemical changes observed. In brief, our findings demonstrated that IPC maintained and even increased KYNA immunoreactivity in the SP of the CA1 region following ischemia-reperfusion. The data from the present study thus indicate that the enhancement of KYNA expression by IPC may be necessary for neuronal survival following transient ischemic injury. PMID:25872573

  10. Ischemic preconditioning protects neurons from damage and maintains the immunoreactivity of kynurenic acid in the gerbil hippocampal CA1 region following transient cerebral ischemia.

    PubMed

    Lee, Jae-Chul; Tae, Hyun-Jin; Cho, Geum-Sil; Kim, In Hye; Ahn, Ji Hyeon; Park, Joon Ha; Chen, Bai Hui; Cho, Jeong-Hwi; Shin, Bich Na; Cho, Jun Hwi; Bae, Eun Joo; Park, Jinseu; Kim, Young-Myeong; Choi, Soo Young; Won, Moo-Ho

    2015-06-01

    Pyramidal neurons in region I of hippocampus proper (CA1) are particularly vulnerable to excitotoxic processes following transient forebrain ischemia. Kynurenic acid (KYNA) is a small molecule derived from tryptophan when this amino acid is metabolized through the kynurenine pathway. In the present study, we examined the effects of ischemic preconditioning (IPC) on the immunoreactivity and protein levels of KYNA following 5 min of transient forebrain ischemia in gerbils. The animals were randomly assigned to 4 groups (sham-operated group, ischemia-operated group, IPC + sham-operated group and IPC + ischemia-operated group). IPC was induced by subjecting the gerbils to 2 min of ischemia followed by 1 day of recovery. In the ischemia-operated group, we observed a significant loss of pyramidal neurons in the CA1 stratum pyramidale (SP) at 5 days post-ischemia; however, in the IPC + ischemia-operated group, the pyramidal neurons were well protected. KYNA immunoreactivity in the SP of the ischemia-operated group was significantly altered following ischemia-reperfusion and was very low 5 days following ischemia-reperfusion. In the IPC + ischemia-operated group, however, KYNA immunoreactivity was constitutively detected in the SP of the CA1 region after the ischemic insult. We also found that the alteration pattern of the KYNA protein level in the CA1 region following ischemia was generally similar to the immunohistochemical changes observed. In brief, our findings demonstrated that IPC maintained and even increased KYNA immunoreactivity in the SP of the CA1 region following ischemia-reperfusion. The data from the present study thus indicate that the enhancement of KYNA expression by IPC may be necessary for neuronal survival following transient ischemic injury. PMID:25872573

  11. Disruption of IP3R2-mediated Ca(2+) signaling pathway in astrocytes ameliorates neuronal death and brain damage while reducing behavioral deficits after focal ischemic stroke.

    PubMed

    Li, Hailong; Xie, Yicheng; Zhang, Nannan; Yu, Yang; Zhang, Qiao; Ding, Shinghua

    2015-12-01

    Inositol trisphosphate receptor (IP3R)-mediated intracellular Ca(2+) increase is the major Ca(2+) signaling pathway in astrocytes in the central nervous system (CNS). Ca(2+) increases in astrocytes have been found to modulate neuronal function through gliotransmitter release. We previously demonstrated that astrocytes exhibit enhanced Ca(2+) signaling in vivo after photothrombosis (PT)-induced ischemia, which is largely due to the activation of G-protein coupled receptors (GPCRs). The aim of this study is to investigate the role of astrocytic IP3R-mediated Ca(2+) signaling in neuronal death, brain damage and behavior outcomes after PT. For this purpose, we conducted experiments using homozygous type 2 IP3R (IP3R2) knockout (KO) mice. Histological and immunostaining studies showed that IP3R2 KO mice were indeed deficient in IP3R2 in astrocytes and exhibited normal brain cytoarchitecture. IP3R2 KO mice also had the same densities of S100?+ astrocytes and NeuN+ neurons in the cortices, and exhibited the same glial fibrillary acidic protein (GFAP) and glial glutamate transporter (GLT-1) levels in the cortices and hippocampi as compared with wild type (WT) mice. Two-photon (2-P) imaging showed that IP3R2 KO mice did not exhibit ATP-induced Ca(2+) waves in vivo in the astrocytic network, which verified the disruption of IP3R-mediated Ca(2+) signaling in astrocytes of these mice. When subject to PT, IP3R2 KO mice had smaller infarction than WT mice in acute and chronic phases of ischemia. IP3R2 KO mice also exhibited less neuronal apoptosis, reactive astrogliosis, and tissue loss than WT mice. Behavioral tests, including cylinder, hanging wire, pole and adhesive tests, showed that IP3R2 KO mice exhibited reduced functional deficits after PT. Collectively, our study demonstrates that disruption of astrocytic Ca(2+) signaling by deleting IP3R2s has beneficial effects on neuronal and brain protection and functional deficits after stroke. These findings reveal a novel non-cell-autonomous neuronal and brain protective function of astrocytes in ischemic stroke, whereby suggest that the astrocytic IP3R2-mediated Ca(2+) signaling pathway might be a promising target for stroke therapy. PMID:26433454

  12. Ischemic preconditioning inhibits expression of Na(+)/H(+) exchanger 1 (NHE1) in the gerbil hippocampal CA1 region after transient forebrain ischemia.

    PubMed

    Lee, Jae-Chul; Cho, Jeong-Hwi; Kim, In Hye; Ahn, Ji Hyeon; Park, Joon Ha; Cho, Geum-Sil; Chen, Bai Hui; Shin, Bich Na; Tae, Hyun-Jin; Park, Seung Min; Ahn, Ji Yun; Kim, Dong Won; Cho, Jun Hwi; Bae, Eun Joo; Yong, Jun-Hwan; Kim, Young-Myeong; Won, Moo-Ho; Lee, Yun Lyul

    2015-04-15

    The participation of Na(+)/H(+) exchanger (NHE) in neuronal damage/death in the hippocampal CA1 region (CA1) induced by transient forebrain ischemia has not been well established, although acidosis may be involved in neuronal damage/death. In the present study, we examined the effect of ischemic preconditioning (IPC) on NHE1 immunoreactivity following a 5min of transient forebrain ischemia in gerbils. The animals used in the study were randomly assigned to four groups (sham-operated-group, ischemia-operated-group, IPC plus (+) sham-operated-group and IPC+ischemia-operated-group). IPC was induced by subjecting animals to 2min of ischemia followed by 1day of recovery. A significant neuronal loss was found in the stratum pyramidale (SP) of the CA1, not the CA2/3, of the ischemia-operated-group at 5days post-ischemia. However, in the IPC+ischemia-operated-group, neurons in the SP of the CA1 were well protected. NHE1 immunoreactivity was not detected in any regions of the CA1-3 of the sham- and IPC+sham-operated-groups. However, the immunoreactivity was apparently expressed in the SP of the CA1-3 after ischemia, and the NHE1immunoreactivity was very weak 5days after ischemia; however, at this point in time, strong NHE1immunoreactivity was found in astrocytes in the CA1. In the CA2/3, NHE1immunoreactivity was slightly changed, although NHE1immunoreactivity was expressed in the SP. In the IPC+ischemia-operated-groups, NHE1 immunoreactivity was also expressed in the SP of the CA1-3; however, the immunoreactivity was more slightly changed than that in the ischemia-operated-groups. In brief, our findings show that IPC dramatically protected CA1 pyramidal neurons and strongly inhibited NHE1 expression in the SP of the CA1 after ischemia-reperfusion. These findings suggest that the inhibition of NHE1 expression may be necessary for neuronal survival from transient ischemic damage. PMID:25783008

  13. Ischemic preconditioning maintains the immunoreactivities of glucokinase and glucokinase regulatory protein in neurons of the gerbil hippocampal CA1 region following transient cerebral ischemia

    PubMed Central

    CHO, YOUNG SHIN; CHO, JUN HWI; SHIN, BICH-NA; CHO, GEUM-SIL; KIM, IN HYE; PARK, JOON HA; AHN, JI HYEON; OHK, TAEK GEUN; CHO, BYUNG-RYUL; KIM, YOUNG-MYEONG; HONG, SEONGKWEON; WON, MOO-HO; LEE, JAE-CHUL

    2015-01-01

    Glucokinase (GK) is involved in the control of blood glucose homeostasis. In the present study, the effect of ischemic preconditioning (IPC) on the immunoreactivities of GK and its regulatory protein (GKRP) following 5 min of transient cerebral ischemia was investigated in gerbils. The gerbils were randomly assigned to four groups (sham-operated group, ischemia-operated group, IPC + sham-operated group and IPC + ischemia-operated group). IPC was induced by subjecting the gerbils to 2 min of ischemia, followed by 1 day of recovery. In the ischemia-operated group, a significant loss of neurons was observed in the stratum pyramidale (SP) of the hippocampal CA1 region (CA1) at 5 days post-ischemia; however, in the IPC+ischemia-operated group, the neurons in the SP were well protected. Following immunohistochemical investigation, the immunoreactivities of GK and GKRP in the neurons of the SP were markedly decreased in the CA1, but not the CA2/3, from 2 days post-ischemia, and were almost undetectable in the SP 5 days post-ischemia. In the IPC + ischemia-operated group, the immunoreactivities of GK and GKRP in the SP of the CA1 were similar to those in the sham-group. In brief, the findings of the present study demonstrated that IPC notably maintained the immunoreactivities of GK and GKRP in the neurons of the SP of CA1 following ischemia-reperfusion. This indicated that GK and GKRP may be necessary for neuron survival against transient cerebral ischemia. PMID:26134272

  14. Ischemic preconditioning maintains the immunoreactivities of glucokinase and glucokinase regulatory protein in neurons of the gerbil hippocampal CA1 region following transient cerebral ischemia.

    PubMed

    Cho, Young Shin; Cho, Jun Hwi; Shin, Bich-Na; Cho, Geum-Sil; Kim, In Hye; Park, Joon Ha; Ahn, Ji Hyeon; Ohk, Taek Geun; Cho, Byung-Ryul; Kim, Young-Myeong; Hong, Seongkweon; Won, Moo-Ho; Lee, Jae-Chul

    2015-10-01

    Glucokinase (GK) is involved in the control of blood glucose homeostasis. In the present study, the effect of ischemic preconditioning (IPC) on the immunoreactivities of GK and its regulatory protein (GKRP) following 5 min of transient cerebral ischemia was investigated in gerbils. The gerbils were randomly assigned to four groups (sham?operated group, ischemia?operated group, IPC + sham?operated group and IPC + ischemia?operated group). IPC was induced by subjecting the gerbils to 2 min of ischemia, followed by 1 day of recovery. In the ischemia?operated group, a significant loss of neurons was observed in the stratum pyramidale (SP) of the hippocampal CA1 region (CA1) at 5 days post?ischemia; however, in the IPC+ischemia?operated group, the neurons in the SP were well protected. Following immunohistochemical investigation, the immunoreactivities of GK and GKRP in the neurons of the SP were markedly decreased in the CA1, but not the CA2/3, from 2 days post?ischemia, and were almost undetectable in the SP 5 days post?ischemia. In the IPC + ischemia?operated group, the immunoreactivities of GK and GKRP in the SP of the CA1 were similar to those in the sham?group. In brief, the findings of the present study demonstrated that IPC notably maintained the immunoreactivities of GK and GKRP in the neurons of the SP of CA1 following ischemia?reperfusion. This indicated that GK and GKRP may be necessary for neuron survival against transient cerebral ischemia. PMID:26134272

  15. Liver ischemia preconditions the heart against ischemia-reperfusion arrhythmias

    PubMed Central

    Noorbakhsh, Mohammad-Foad; Arab, Hossein-Ali; Kazerani, Hamid-Reza

    2015-01-01

    Objective(s): This study aimed to examine the hypothesis that an antiarrhythmic effect might be obtained by ischemic preconditioning of the liver, and also to characterize the potential underlying mechanisms. Materials and Methods: Male Wistar rats were anesthetized by thiopental sodium (50 mg/kg, IP) followed by IV injection of heparin (250 IU). Remote ischemic preconditioning (RIPC) was induced by 3 cycles of 5 min liver ischemia followed by 5 min of reperfusion. The hearts were excised within 5 min after the final cycle of preconditioning and perfused using Langendorff’s system. The isolated perfused hearts were subjected to 30 min global ischemia followed by 90 min reperfusion. The myocardial arrhythmias induced by ischemia- reperfusion (I/R) were determined in accordance with the guidelines of Lambeth Conventions. The potential role of KATP channels on RIPC was assessed by injection of glibenclamide (nonselective KATP blocker) or 5-hydroxydecanoate (mitochondrial KATP blocker) on rats 30 and 15 min before induction of RIPC in the liver, respectively. Results: Hepatic remote preconditioning of the heart significantly (P<0.0001) prevented the incidence of myocardial arrhythmias induced by I/R in the perfused hearts (5.33±1.54 vs. 32.33±6.44,). However, the protective effects of remote preconditioning was significantly (P<0.01) abolished by the KATP blocker, glibenclamide (25.5±4.9 vs. 5.33±1.54,). Conclusion: Hepatic RIPC may prevent the arrhythmias induced by I/R in the isolated perfused hearts via KATP channels. PMID:25810880

  16. Pharmacological Preconditioning by Adenosine A2a Receptor Stimulation: Features of the Protected Liver Cell Phenotype

    PubMed Central

    Alchera, Elisa; Imarisio, Chiara; Mandili, Giorgia; Merlin, Simone; Chandrashekar, Bangalore R.; Novelli, Francesco; Follenzi, Antonia; Carini, Rita

    2015-01-01

    Ischemic preconditioning (IP) of the liver by a brief interruption of the blood flow protects the damage induced by a subsequent ischemia/reperfusion (I/R) preventing parenchymal and nonparenchymal liver cell damage. The discovery of IP has shown the existence of intrinsic systems of cytoprotection whose activation can stave off the progression of irreversible tissue damage. Deciphering the molecular mediators that underlie the cytoprotective effects of preconditioning can pave the way to important therapeutic possibilities. Pharmacological activation of critical mediators of IP would be expected to emulate or even to intensify its salubrious effects. In vitro and in vivo studies have demonstrated the role of the adenosine A2a receptor (A2aR) as a trigger of liver IP. This review will provide insight into the phenotypic changes that underline the resistance to death of liver cells preconditioned by pharmacological activation of A2aR and their implications to develop innovative strategies against liver IR damage. PMID:26539478

  17. Differential expression of microRNAs in ischemic heart disease.

    PubMed

    Song, Minwoo A; Paradis, Alexandra N; Gay, Maresha S; Shin, John; Zhang, Lubo

    2015-02-01

    Recent studies provide evidence that ischemic preconditioning (IP) and ischemia/reperfusion (IR) injury lead to altered expression of microRNAs (miRNAs) that affect the survival and recovery of cardiomyocytes. These endogenous ?22-nucleotide noncoding RNAs negatively regulate gene expression via degradation and translational inhibition of their target mRNAs. miRNAs are involved in differentiation, proliferation, electrical conduction, angiogenesis and apoptosis. These pathways can lead to physiological and pathological adaptations. This review intends to explore several facets of miRNA expression and the underlying mechanisms involved in IR injury, as well as IP as a cardioprotective strategy. In addition, we will investigate miRNA interaction with the renin-angiotensin system and the potential use of miRNAs in developing sensitive biomarkers for cardiovascular disease. PMID:25461956

  18. The Effect of Pre-Condition Cerebella Fastigial Nucleus Electrical Stimulation within and beyond the Time Window of Thrombolytic on Ischemic Stroke in the Rats

    PubMed Central

    Cheng, Pengfei; Bai, Shunjie; Ren, Yifei; Wang, Gong; Chen, Xiuying; Cui, Chun; Zhuang, Yuxiang

    2015-01-01

    Objective To investigate the effect of neurogenic neuroprotection conferred by cerebellar fastigial nucleus stimulation (FNS) and the role of PPAR?- mediated inflammation in a rat model of cerebral ischemia reperfusion. Methods After a continuous 1 hour fastigial nucleus electric stimulation, the male Sprague Dawley (SD) rats were given middle cerebral artery occlusion (MCAO) for 1, 3, 6, 9, 12 and 15 hours undergoing reperfusion with intravenous recombinant tissue plasminogen activator (rt-PA), while the control group received without FNS. After 72h of reperfusion, the neurological deficits, infarct volume and brain edema were evaluated. The brain tissue in ischemic penumbra was determined the myeloperoxidase (MPO) activity by a spectrophotometer and expression of PPAR? was measured by Rt-PCR and Western blotting. Results Our findings showed that FNS group had significantly reduced infarct volume and brain edema, and improved neurological deficits compared with the control group, especially in 6h and 9h reperfusion subgroups(p<0.05). The expression levels of PPAR? increased gradually and the peak may be before and after 9h reperfusion, the 3h, 6h, 9h, 12h and 15h reperfusion subgroups were higher than each control group(p<0.05). The MPO activity of 6h, 12h and 15h reperfusion subgroups were higher than each control group(p<0.05). Conclusions The neuroprotective effects of FNS have been shown to prolong the therapeutic window in cerebral ischemia/reperfusion, which might be related to the PPAR? mediated-inflammation in penumbral region. PMID:26016630

  19. Astrocyte-mediated ischemic tolerance.

    PubMed

    Hirayama, Yuri; Ikeda-Matsuo, Yuri; Notomi, Shoji; Enaida, Hiroshi; Kinouchi, Hiroyuki; Koizumi, Schuichi

    2015-03-01

    Preconditioning (PC) using a preceding sublethal ischemic insult is an attractive strategy for protecting neurons by inducing ischemic tolerance in the brain. Although the underlying molecular mechanisms have been extensively studied, almost all studies have focused on neurons. Here, using a middle cerebral artery occlusion model in mice, we show that astrocytes play an essential role in the induction of brain ischemic tolerance. PC caused activation of glial cells without producing any noticeable brain damage. The spatiotemporal pattern of astrocytic, but not microglial, activation correlated well with that of ischemic tolerance. Interestingly, such activation in astrocytes lasted at least 8 weeks. Importantly, inhibiting astrocytes with fluorocitrate abolished the induction of ischemic tolerance. To investigate the underlying mechanisms, we focused on the P2X7 receptor as a key molecule in astrocyte-mediated ischemic tolerance. P2X7 receptors were dramatically upregulated in activated astrocytes. PC-induced ischemic tolerance was abolished in P2X7 receptor knock-out mice. Moreover, our results suggest that hypoxia-inducible factor-1?, a well known mediator of ischemic tolerance, is involved in P2X7 receptor-mediated ischemic tolerance. Unlike previous reports focusing on neuron-based mechanisms, our results show that astrocytes play indispensable roles in inducing ischemic tolerance, and that upregulation of P2X7 receptors in astrocytes is essential. PMID:25740510

  20. Cardiac sodium/calcium exchanger preconditioning promotes anti-arrhythmic and cardioprotective effects through mitochondrial calcium-activated potassium channel

    PubMed Central

    Zhang, Jian-Ying; Cheng, Kang; Lai, Dong; Kong, Ling-Heng; Shen, Min; Yi, Fu; Liu, Bing; Wu, Feng; Zhou, Jing-Jun

    2015-01-01

    Background: Reverse-mode of the Na+/Ca2+ exchanger (NCX) stimulation provides cardioprotective effects for the ischemic/reperfused heart during ischemic preconditioning (IP). This study was designed to test the hypothesis that pretreatment with an inhibitor of cardiac delayed-rectifying K+ channel (IKr), E4031, increases reverse-mode of NCX activity, and triggers preconditioning against infarct size (IS) and arrhythmias caused by ischemia/reperfusion injury through mitoKCa channels. Materials and methods: In the isolated perfused rat heart, myocardial ischemia/reperfusion injury was created by occlusion of the left anterior descending coronary artery for 30 min followed by 120 min reperfusion. Two cycles of coronary occlusion for 5 min and reperfusion were performed, or pretreatment with E4031 or sevoflurane (Sevo) before the 30 min occlusion with the reversed-mode of NCX inhibitor (KB-R7943) or not. Results: E4031 or Sevo preconditioning not only markedly decreased IS but also reduced arrhythmias, which was significantly blunted by KB-R7943. Furthermore, these effects of E4031 preconditioning on IS and arrhythmias were abolished by inhibition of the mitoKCa channels. Similarly, pretreatment with NS1619, an opener of the mitoKCa channels, for 10 min before occlusion reduced both the infarct size and arrhythmias caused by ischemia/reperfusion. However, these effects weren’t affected by blockade of the NCX with KB-R7943. Conclusion: Taken together, these preliminary results conclude that pretreatment with E4031 reduces infarct size and produces anti-arrhythmic effect via stimulating the reverse-mode NCX, and that the mitoKCa channels mediate the protective effects. PMID:26617732

  1. Myocardial ischemic protection in natural mammalian hibernation.

    PubMed

    Yan, Lin; Kudej, Raymond K; Vatner, Dorothy E; Vatner, Stephen F

    2015-03-01

    Hibernating myocardium is an important clinical syndrome protecting the heart with chronic myocardial ischemia, named for its assumed resemblance to hibernating mammals in winter. However, the effects of myocardial ischemic protection have never been studied in true mammalian hibernation, which is a unique strategy for surviving extreme winter environmental stress. The goal of this investigation was to test the hypothesis that ischemic stress may also be protected in woodchucks as they hibernate in winter. Myocardial infarction was induced by coronary occlusion followed by reperfusion in naturally hibernating woodchucks in winter with and without hibernation and in summer, when not hibernating. The ischemic area at risk was similar among groups. Myocardial infarction was significantly less in woodchucks in winter, whether hibernating or not, compared with summer, and was similar to that resulting after ischemic preconditioning. Whereas several genes were up or downregulated in both hibernating woodchuck and with ischemic preconditioning, one mechanism was unique to hibernation, i.e., activation of cAMP-response element binding protein (CREB). When CREB was upregulated in summer, it induced protection similar to that observed in the woodchuck heart in winter. The cardioprotection in hibernation was also mediated by endothelial nitric oxide synthase, rather than inducible nitric oxide synthase. Thus, the hibernating woodchuck heart is a novel model to study cardioprotection for two major reasons: (1) powerful cardioprotection occurs naturally in winter months in the absence of any preconditioning stimuli, and (2) it resembles ischemic preconditioning, but with novel mechanisms, making this model potentially useful for clinical translation. PMID:25613166

  2. Ischemic Stroke

    MedlinePLUS

    A stroke is a medical emergency. There are two types - ischemic and hemorrhagic. Ischemic stroke is the most common type. It is usually ... are at risk for having a more serious stroke. Symptoms of stroke are Sudden numbness or weakness ...

  3. Effects of ischemia and omeprazole preconditioning on functional recovery of isolated rat heart

    PubMed Central

    Jeremic, Nevena; Petkovic, Anica; Srejovic, Ivan; Zivkovic, Vladimir; Djuric, Dragan; Jakovljevic, Vladimir

    2015-01-01

    Objective The aim of this study was to compare protective effects of ischemic and potential protective effects of pharmacological preconditioning with omeprazole on isolated rat heart subjected to ischemia/reperfusion. Methods The hearts of male Wistar albino rats were excised and perfused on a Langendorff apparatus. In control group (CG) after stabilization period, hearts were subjected to global ischemia (perfusion was totally stopped) for 20 minutes and 30 minutes of reperfusion. Hearts of group II (IPC) were submitted to ischemic preconditioning lasting 5 minutes before 20 minutes of ischemia and 30 minutes of reperfusion. In third group (OPC) hearts first underwent preconditioning lasting 5 minutes with 100?M omeprazole, and then submitted 20 minutes of ischemia and 30 minutes of reperfusion. Results Administration of omeprazole before ischemia induction had protective effect on myocardium function recovery especially regarding to values of systolic left ventricular pressure and dp/dt max. Also our findings are that values of coronary flow did not change between OPC and IPC groups in last point of reperfusion. Conclusion Based on our results it seems that ischemic preconditioning could be used as first window of protection after ischemic injury especially because all investigated parameters showed continuous trend of recovery of myocardial function. On the other hand, preconditioning with omeprazole induced sudden trend of recovery with positive myocardium protection, although less effective than results obtained with ischemic preconditioning not withstand, we must consider that omeprazole may be used in many clinical circumstances where direct coronary clamping for ischemic preconditioning is not possible. PMID:26107460

  4. Mesenchymal stem cells preconditioned with trimetazidine promote neovascularization of hearts under hypoxia/reoxygenation injury

    PubMed Central

    Hu, Xiaowu; Yang, Junjie; Wang, Ying; Zhang, You; Ii, Masaaki; Shen, Zhenya; Hui, Jie

    2015-01-01

    Background: Cell-based angiogenesis is a promising treatment for ischemic diseases; however, survival of implanted cells is impaired by the ischemic microenvironment. In this study, mesenchymal stem cells (MSCs) for cell transplantation were preconditioned with trimetazidine (TMZ). We hypothesized that TMZ enhances the survival rate of MSCs under hypoxic stimuli through up-regulation of HIF1-?. Methods and results: Bone marrow-derived rat mesenchymal stem cells were preconditioned with 10 ?M TMZ for 6 h. TMZ preconditioning of MSCs remarkably increased cell viability and the expression of HIF1-? and Bcl-2, when cells were under hypoxia/reoxygenation (H/R) stimuli. But the protective effects of TMZ were abolished after knocking down of HIF-1?. Three days after implantation of the cells into the peri-ischemic zone of rat myocardial ischemia-reperfusion (I/R) injury model, survival of the TMZ-preconditioned MSCs was high. Furthermore, capillary density and cardiac function were significantly better in the rats implanted with TMZ-preconditioned MSCs 28 days after cell injection. Conclusions: TMZ preconditioning increased the survival rate of MSCs, through up-regulation of HIF1-?, thus contributing to neovascularization and improved cardiac function of rats subjected to myocardial I/R injury.

  5. The evolving concept of physiological ischemia training vs. ischemia preconditioning.

    PubMed

    Ni, Jun; Lu, Hongjian; Lu, Xiao; Jiang, Minghui; Peng, Qingyun; Ren, Caili; Xiang, Jie; Mei, Chengyao; Li, Jianan

    2015-11-01

    Ischemic heart diseases are the leading cause of death with increasing numbers of patients worldwide. Despite advances in revascularization techniques, angiogenic therapies remain highly attractive. Physiological ischemia training, which is first proposed in our laboratory, refers to reversible ischemia training of normal skeletal muscles by using a tourniquet or isometric contraction to cause physiologic ischemia for about 4 weeks for the sake of triggering molecular and cellular mechanisms to promote angiogenesis and formation of collateral vessels and protect remote ischemia areas. Physiological ischemia training therapy augments angiogenesis in the ischemic myocardium by inducing differential expression of proteins involved in energy metabolism, cell migration, protein folding, and generation. It upregulates the expressions of vascular endothelial growth factor, and induces angiogenesis, protects the myocardium when infarction occurs by increasing circulating endothelial progenitor cells and enhancing their migration, which is in accordance with physical training in heart disease rehabilitation. These findings may lead to a new approach of therapeutic angiogenesis for patients with ischemic heart diseases. On the basis of the promising results in animal studies, studies were also conducted in patients with coronary artery disease without any adverse effect in vivo, indicating that physiological ischemia training therapy is a safe, effective and non-invasive angiogenic approach for cardiovascular rehabilitation. Preconditioning is considered to be the most protective intervention against myocardial ischemia-reperfusion injury to date. Physiological ischemia training is different from preconditioning. This review summarizes the preclinical and clinical data of physiological ischemia training and its difference from preconditioning. PMID:26664354

  6. The evolving concept of physiological ischemia training vs. ischemia preconditioning

    PubMed Central

    Ni, Jun; Lu, Hongjian; Lu, Xiao; Jiang, Minghui; Peng, Qingyun; Ren, Caili; Xiang, Jie; Mei, Chengyao; Li, Jianan

    2015-01-01

    Abstract Ischemic heart diseases are the leading cause of death with increasing numbers of patients worldwide. Despite advances in revascularization techniques, angiogenic therapies remain highly attractive. Physiological ischemia training, which is first proposed in our laboratory, refers to reversible ischemia training of normal skeletal muscles by using a tourniquet or isometric contraction to cause physiologic ischemia for about 4 weeks for the sake of triggering molecular and cellular mechanisms to promote angiogenesis and formation of collateral vessels and protect remote ischemia areas. Physiological ischemia training therapy augments angiogenesis in the ischemic myocardium by inducing differential expression of proteins involved in energy metabolism, cell migration, protein folding, and generation. It upregulates the expressions of vascular endothelial growth factor, and induces angiogenesis, protects the myocardium when infarction occurs by increasing circulating endothelial progenitor cells and enhancing their migration, which is in accordance with physical training in heart disease rehabilitation. These findings may lead to a new approach of therapeutic angiogenesis for patients with ischemic heart diseases. On the basis of the promising results in animal studies, studies were also conducted in patients with coronary artery disease without any adverse effect in vivo, indicating that physiological ischemia training therapy is a safe, effective and non-invasive angiogenic approach for cardiovascular rehabilitation. Preconditioning is considered to be the most protective intervention against myocardial ischemia-reperfusion injury to date. Physiological ischemia training is different from preconditioning. This review summarizes the preclinical and clinical data of physiological ischemia training and its difference from preconditioning.

  7. Cardioprotection by remote ischemic conditioning: Mechanisms and clinical evidences

    PubMed Central

    Aimo, Alberto; Borrelli, Chiara; Giannoni, Alberto; Pastormerlo, Luigi Emilio; Barison, Andrea; Mirizzi, Gianluca; Emdin, Michele; Passino, Claudio

    2015-01-01

    In remote ischemic conditioning (RIC), several cycles of ischemia and reperfusion render distant organ and tissues more resistant to the ischemia-reperfusion injury. The intermittent ischemia can be applied before the ischemic insult in the target site (remote ischemic preconditioning), during the ischemic insult (remote ischemic perconditioning) or at the onset of reperfusion (remote ischemic postconditioning). The mechanisms of RIC have not been completely defined yet; however, these mechanisms must be represented by the release of humoral mediators and/or the activation of a neural reflex. RIC has been discovered in the heart, and has been arising great enthusiasm in the cardiovascular field. Its efficacy has been evaluated in many clinical trials, which provided controversial results. Our incomplete comprehension of the mechanisms underlying the RIC could be impairing the design of clinical trials and the interpretation of their results. In the present review we summarize current knowledge about RIC pathophysiology and the data about its cardioprotective efficacy. PMID:26516416

  8. Rapid degradation of Bim by the ubiquitin-proteasome pathway mediates short-term ischemic tolerance in cultured neurons.

    PubMed

    Meller, Robert; Cameron, Jennifer Anastasia; Torrey, Daniel John; Clayton, Corrin Erin; Ordonez, Andrea Nicole; Henshall, David Clifford; Minami, Manabu; Schindler, Clara Kay; Saugstad, Julie Anne; Simon, Roger Pancoast

    2006-03-17

    A previous exposure to a non-harmful ischemic insult (preconditioning) protects the brain against subsequent harmful ischemia (ischemic tolerance). In contrast to delayed gene-mediated ischemic tolerance, little is known about the molecular mechanisms that regulate rapid ischemic tolerance, which occurs within 1 h following preconditioning. Here we have investigated the degradation of the pro-apoptotic Bcl-2 family member Bim as a mechanism of rapid ischemic tolerance. Bim protein levels were reduced 1 h following preconditioning and occurred concurrent with an increase in Bim ubiquitination. Ubiquitinated proteins are degraded by the proteasome, and inhibition of the proteasome with MG132 (a proteasome inhibitor) prevented Bim degradation and blocked rapid ischemic tolerance. Inhibition of p42/p44 mitogen-activated protein kinase activation by U0126 reduced Bim ubiquitination and Bim degradation and blocked rapid ischemic tolerance. Finally, inhibition of Bim expression using antisense oligonucleotides also reduced cell death following ischemic challenge. Our results suggest that following preconditioning ischemia, Bim is rapidly degraded by the ubiquitin-proteasome system, resulting in rapid ischemic tolerance. This suggests that the rapid degradation of cell death-promoting proteins by the ubiquitin-proteasome pathway may represent a novel therapeutic strategy to reduce cell damage following neuropathological insults, e.g. stroke. PMID:16431916

  9. Bradykinin in ischemic conditioning-induced tissue protection: Evidences and possible mechanisms.

    PubMed

    Sharma, Roohani; Randhawa, Puneet Kaur; Singh, Nirmal; Jaggi, Amteshwar Singh

    2015-12-01

    Ischemic conditioning is an intrinsic protective mechanism in which repeated short episodes of reversible ischemia protects the tissue and increases its tolerance against a subsequent longer period of ischemia (index ischemia). Bradykinin is a physiologically and pharmacologically active peptide of the kallikrein-kinin system. Besides the involvement of bradykinin in a variety of physiological and pathological responses such as pain, inflammation and in cardiovascular system as a potent vasodilator, it also acts as an endogenous cytoprotective mediator in the ischemic tissue. Pretreatment with various pharmacological modulators of bradykinin has confirmed the involvement of bradykinin in ischemic conditioning-induced protection. The protective actions of bradykinin in three major paradigms of ischemic conditioning i.e. ischemic preconditioning, ischemic postconditioning and remote ischemic preconditioning involves activation and regulation of various endogenous signaling cascades to render the heart resistant to infarction. In ischemic preconditioning, bradykinin exerts cardioprotective effect via activation of PI3K/Akt/eNOS signaling pathway and regulation of redox state via NO release. The role of bradykinin and its B2 receptors in ischemic-postconditioning induced neuroprotection has been described mainly due to its increased redox signaling cascade and activation of mitochondrial anti-apoptotic pathway. Furthermore, its cardioprotective role during remote ischemic preconditioning has been associated with activation of B2 receptors mediated neurogenic pathway and internalization of B2 receptors along with the formation of signalosomes that activates intracellular cytoprotective transduction pathways. The present review focuses on the potential role of bradykinin in mediating different forms of ischemic conditioning (pre/post/remote)-induced cardioprotection and neuroprotection along with the possible mechanisms. PMID:26499976

  10. Roles of thioredoxin in nitric oxide-dependent preconditioning-induced tolerance against MPTP neurotoxin

    SciTech Connect

    Chiueh, C.C. . E-mail: chiueh@tmu.edu.tw; Andoh, Tsugunobu; Chock, P. Boon

    2005-09-01

    Hormesis, a stress tolerance, can be induced by ischemic preconditioning stress. In addition to preconditioning, it may be induced by other means, such as gas anesthetics. Preconditioning mechanisms, which may be mediated by reprogramming survival genes and proteins, are obscure. A known neurotoxicant, 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), causes less neurotoxicity in the mice that are preconditioned. Pharmacological evidences suggest that the signaling pathway of {center_dot}NO-cGMP-PKG (protein kinase G) may mediate preconditioning phenomenon. We developed a human SH-SY5Y cell model for investigating {sup {center_dot}}NO-mediated signaling pathway, gene regulation, and protein expression following a sublethal preconditioning stress caused by a brief 2-h serum deprivation. Preconditioned human SH-SY5Y cells are more resistant against severe oxidative stress and apoptosis caused by lethal serum deprivation and 1-mehtyl-4-phenylpyridinium (MPP{sup +}). Both sublethal and lethal oxidative stress caused by serum withdrawal increased neuronal nitric oxide synthase (nNOS/NOS1) expression and {sup {center_dot}}NO levels to a similar extent. In addition to free radical scavengers, inhibition of nNOS, guanylyl cyclase, and PKG blocks hormesis induced by preconditioning. S-nitrosothiols and 6-Br-cGMP produce a cytoprotection mimicking the action of preconditioning tolerance. There are two distinct cGMP-mediated survival pathways: (i) the up-regulation of a redox protein thioredoxin (Trx) for elevating mitochondrial levels of antioxidant protein Mn superoxide dismutase (MnSOD) and antiapoptotic protein Bcl-2, and (ii) the activation of mitochondrial ATP-sensitive potassium channels [K(ATP)]. Preconditioning induction of Trx increased tolerance against MPP{sup +}, which was blocked by Trx mRNA antisense oligonucleotide and Trx reductase inhibitor. It is concluded that Trx plays a pivotal role in {sup {center_dot}}NO-dependent preconditioning hormesis against MPTP/MPP{sup +}.

  11. Thrombin Preconditioning in Surgical Brain Injury in Rats.

    PubMed

    Benggon, Michael; Chen, Hank; Applegate, Richard L; Zhang, John

    2016-01-01

    The surgical brain injury model replicates neurosurgical brain parenchymal damage. Postsurgical brain edema correlates with postoperative neurological dysfunction. Intranasal administration is a proven method of delivering therapies to brain tissue. Thrombin preconditioning decreased brain edema and improved neurological outcomes in models of ischemic brain injury. We hypothesized thrombin preconditioning in surgical brain injury may improve postoperative brain edema and neurological outcomes. Adult male Sprague-Dawley rats (n?=?78) weighing 285-355 g were randomly assigned to sham or pre-injury treatment: one-time pretreatment 1 day prior, one-time pretreatment 5 days prior, and daily preconditioning for 5 days prior. Treatment arms were divided into vehicle or thrombin therapies, and subdivided into intranasal (thrombin 5 units/50 ?L 0.9 % saline) or intracerebral ventricular (thrombin 0.1 unit/10 ?L 0.9 % saline) administration. Blinded observers performed neurological testing 24 h after brain injury followed immediately by measurement of brain water content. There was a significant difference in ipsilateral brain water content and neurological outcomes between all treatment groups and the sham group. However, there was no change in brain water content or neurological outcomes between thrombin- and vehicle-treated animals. Thrombin preconditioning did not significantly improve brain edema or neurological function in surgical brain injury in rats. PMID:26463965

  12. Systemic chemokine levels, coronary heart disease, and ischemic stroke events

    PubMed Central

    Canouï-Poitrine, F.; Luc, G.; Mallat, Z.; Machez, E.; Bingham, A.; Ferrieres, J.; Ruidavets, J.-B.; Montaye, M.; Yarnell, J.; Haas, B.; Arveiler, D.; Morange, P.; Kee, F.; Evans, A.; Amouyel, P.; Ducimetiere, P.

    2011-01-01

    Objectives: To quantify the association between systemic levels of the chemokine regulated on activation normal T-cell expressed and secreted (RANTES/CCL5), interferon-?-inducible protein-10 (IP-10/CXCL10), monocyte chemoattractant protein-1 (MCP-1/CCL2), and eotaxin-1 (CCL11) with future coronary heart disease (CHD) and ischemic stroke events and to assess their usefulness for CHD and ischemic stroke risk prediction in the PRIME Study. Methods: After 10 years of follow-up of 9,771 men, 2 nested case-control studies were built including 621 first CHD events and 1,242 matched controls and 95 first ischemic stroke events and 190 matched controls. Standardized hazard ratios (HRs) for each log-transformed chemokine were estimated by conditional logistic regression. Results: None of the 4 chemokines were independent predictors of CHD, either with respect to stable angina or to acute coronary syndrome. Conversely, RANTES (HR = 1.70; 95% confidence interval [CI] 1.05–2.74), IP-10 (HR = 1.53; 95% CI 1.06–2.20), and eotaxin-1 (HR = 1.59; 95% CI 1.02–2.46), but not MCP-1 (HR = 0.99; 95% CI 0.68–1.46), were associated with ischemic stroke independently of traditional cardiovascular risk factors, hs-CRP, and fibrinogen. When the first 3 chemokines were included in the same multivariate model, RANTES and IP-10 remained predictive of ischemic stroke. Their addition to a traditional risk factor model predicting ischemic stroke substantially improved the C-statistic from 0.6756 to 0.7425 (p = 0.004). Conclusions: In asymptomatic men, higher systemic levels of RANTES and IP-10 are independent predictors of ischemic stroke but not of CHD events. RANTES and IP-10 may improve the accuracy of ischemic stroke risk prediction over traditional risk factors. PMID:21849651

  13. Preconditioning Provides Neuroprotection in Models of CNS Disease: Paradigms and Clinical Significance

    PubMed Central

    Stetler, R. Anne; Leak, Rehana K.; Gan, Yu; Li, Peiying; Hu, Xiaoming; Jing, Zheng; Chen, Jun; Zigmond, Michael J.; Gao, Yanqin

    2014-01-01

    Preconditioning is a phenomenon in which brief episodes of a sublethal insult induce robust protection against subsequent lethal injuries. Preconditioning has been observed in multiple organisms and can occur in the brain as well as other tissues. Extensive animal studies suggest that the brain can be preconditioned to resist acute injuries, such as ischemic stroke, neonatal hypoxia/ischemia, trauma, and agents that are used in models of neurodegenerative diseases, such as Parkinson’s disease and Alzheimer’s disease. Effective preconditioning stimuli are numerous and diverse, ranging from transient ischemia, hypoxia, hyperbaric oxygen, hypothermia and hyperthermia, to exposure to neurotoxins and pharmacological agents. The phenomenon of “cross-tolerance,” in which a sublethal stress protects against a different type of injury, suggests that different preconditioning stimuli may confer protection against a wide range of injuries. Research conducted over the past few decades indicates that brain preconditioning is complex, involving multiple effectors such as metabolic inhibition, activation of extra- and intracellular defense mechanisms, a shift in the neuronal excitatory/inhibitory balance, and reduction in inflammatory sequelae. An improved understanding of brain preconditioning should help us identify innovative therapeutic strategies that prevent or at least reduce neuronal damage in susceptible patients. In this review, we focus on the experimental evidence of preconditioning in the brain and systematically survey the models used to develop paradigms for neuroprotection, and then discuss the clinical potential of brain preconditioning. In a subsequent components of this two-part series, we will discuss the cellular and molecular events that are likely to underlie these phenomena. PMID:24389580

  14. STAT transcription in the ischemic heart

    PubMed Central

    Knight, Richard A.; Scarabelli, Tiziano M.; Stephanou, Anastasis

    2012-01-01

    All seven STAT proteins are expressed in the heart, and in this review we will focus on their contribution to cardiac physiology and to ischemic heart disease and its consequences. A substantial literature has focused on the roles of STAT1 and STAT3 in ischemic heart disease, where, at least in the acute phase, they appear to have a yin-yang relationship. STAT1 contributes to the loss of irreplaceable cardiac myocytes both by increasing apoptosis and by reducing cardioprotective autophagy. In contrast, STAT3 is cardioprotective, since STAT3-deficient mice have larger infarcts following ischemic injury, and a number of cardioprotective agents have been shown to act, at least partly, through STAT3 activation. STAT3 is also absolutely required for preconditioning—a process where periods of brief ischemia protect against a subsequent or previous prolonged ischemic episode. Prolonged activation of STAT3, however, is strongly implicated in the post-infarction remodeling of the heart which leads to heart failure, where, possibly together with STAT5, it augments activation of the renin-angiotensin system. PMID:24058759

  15. Role of Circulating Immune Cells in Stroke and Preconditioning-Induced Protection.

    PubMed

    Gesuete, Raffaella; Stevens, Susan L; Stenzel-Poore, Mary P

    2016-01-01

    Stroke activates an inflammatory response that results in the infiltration of peripheral immune cells into the ischemic area, contributing to exacerbation of tissue damage. However, evidence indicates that inflammatory cell infiltration can also promote neuroprotection through regulatory immune cells that mitigate injury. These immune regulatory cells may also be important mediators of neuroprotection associated with preconditioning, a phenomenon whereby small exposure to a potential harmful stimulus is able to induce protection against a subsequent ischemic event. The elucidation of mechanisms that allow these immune cells to confer neuroprotection is critical to developing new therapeutic strategies against acute stroke. In the present review, we discuss the dual role of peripheral immune cells in stroke-related brain injury and neuroprotection. Furthermore, we report new data from our laboratory that supports the important role of peripheral cells and their interaction with the brain endothelium for the establishment of the protective phenotype in preconditioning. PMID:26463920

  16. Adenosine A1 receptor activation modulates N-methyl-d-aspartate (NMDA) preconditioning phenotype in the brain.

    PubMed

    Constantino, Leandra C; Pamplona, Fabrício A; Matheus, Filipe C; Ludka, Fabiana K; Gomez-Soler, Maricel; Ciruela, Francisco; Boeck, Carina R; Prediger, Rui D; Tasca, Carla I

    2015-04-01

    N-methyl-d-aspartate (NMDA) preconditioning is induced by subtoxic doses of NMDA and it promotes a transient state of resistance against subsequent lethal insults. Interestingly, this mechanism of neuroprotection depends on adenosine A1 receptors (A1R), since blockade of A1R precludes this phenomenon. In this study we evaluated the consequences of NMDA preconditioning on the hippocampal A1R biology (i.e. expression, binding properties and functionality). Accordingly, we measured A1R expression in NMDA preconditioned mice (75mg/kg, i.p.; 24h) and showed that neither the total amount of receptor, nor the A1R levels in the synaptic fraction was altered. In addition, the A1R binding affinity to the antagonist [(3)H] DPCPX was slightly increased in total membrane extracts of hippocampus from preconditioned mice. Next, we evaluated the impact of NMDA preconditioning on A1R functioning by measuring the A1R-mediated regulation of glutamate uptake into hippocampal slices and on behavioral responses in the open field and hot plate tests. NMDA preconditioning increased glutamate uptake into hippocampal slices without altering the expression of glutamate transporter GLT-1. Interestingly, NMDA preconditioning also induced antinociception in the hot plate test and both effects were reversed by post-activation of A1R with the agonist CCPA (0.2mg/kg, i.p.). NMDA preconditioning or A1R modulation did not alter locomotor activity in the open field. Overall, the results described herein provide new evidence that post-activation of A1R modulates NMDA preconditioning-mediated responses, pointing to the importance of the cross-talk between glutamatergic and adenosinergic systems to neuroprotection. PMID:25557798

  17. Orderings for conjugate gradient preconditionings

    NASA Technical Reports Server (NTRS)

    Ortega, James M.

    1991-01-01

    The effect of orderings on the rate of convergence of the conjugate gradient method with SSOR or incomplete Cholesky preconditioning is examined. Some results also are presented that help to explain why red/black ordering gives an inferior rate of convergence.

  18. Diazoxide preconditioning of endothelial progenitor cells improves their ability to repair the infarcted myocardium.

    PubMed

    Mehmood, Azra; Ali, Muhammad; Khan, Shaheen N; Riazuddin, Sheikh

    2015-11-01

    Reduced survival and homing of the transplanted cells in the oxidative stressed ischemic environment limits the potential outcome of cell therapies for myocardial ischemia. Diazoxide (DZ), a highly selective mitochondrial ATP sensitive K(+) channel opener, is known to improve the survival and therapeutic ability of mesenchymal stem cells and skeletal myoblasts for the repair of heart failure. The current study explored the effect of DZ preconditioning in improving the ability of endothelial progenitor cells (EPCs) to counteract, in vitro oxidative stress, and to repair the infarcted myocardium. The EPCs were preconditioned by 30?min incubation with 200??M DZ followed by exposure to 200??M hydrogen peroxide (H2 O2 ) for 2?h. Non-preconditioned EPCs with and without exposure to H2 O2 were used as control. DZ preconditioning of EPCs resulted in significantly reduced cell injury as shown by reduced lactate dehydrogenase release and expression of annexin V-PE in comparison to untreated EPCs. Furthermore, DZ preconditioned EPCs exhibited upregulated expression of prosurvival genes (VEGF, SDF-1?, PCNA, and Bcl2 ), improved chemokines release (VEGF, IGF, and SDF-1?), viability, Akt phosphorylation and tube formation. In vivo experiments involved transplantation of DZ preconditioned and untreated EPCs in the left ventricle after permanent ligation of left anterior descending coronary artery in rats. The results demonstrated that DZ EPCs transplanted group showed significant reduction in infarct size along with robust cell proliferation, angiogenesis and improvement in cardiac function. The current study demonstrates that DZ preconditioning enhances EPCs survival under oxidative stress in vitro and their ability to treat myocardial infarction. PMID:26032287

  19. Lipopolysaccharide preconditioning prevents acceleration of kindling epileptogenesis induced by traumatic brain injury.

    PubMed

    Eslami, Mansoureh; Sayyah, Mohammad; Soleimani, Mansoureh; Alizadeh, Leila; Hadjighassem, Mahmoudreza

    2015-12-15

    10-20% of symptomatic epilepsies are post-traumatic. We examined effect of LPS preconditioning on epileptogenesis after controlled cortical impact (CCI). LPS (0.01, 0.1 and 0.5mg/kg) was injected i.p. to rats 5days before induction of CCI to parieto-temporal cortex. Kindling started 24h after CCI by i.p. injection of 30mg/kg of pentylenetetrazole every other day until manifestation of 3 consecutive generalized seizures. CCI injury accelerated the rate of kindled seizures acquisition. LPS (0.1 and 0.5mg/kg) prevented the acceleration of kindling. LPS preconditioning significantly decreased IL-1? and TNF-? over-expression and the number of damaged neurons in the hippocampus of traumatic rats. PMID:26616884

  20. PVM and IP multicast

    SciTech Connect

    Dunigan, T.H.; Hall, K.A.

    1996-12-01

    This report describes a 1994 demonstration implementation of PVM that uses IP multicast. PVM`s one-to-many unicast implementation of its pvm{_}mcast() function is replaced with reliable IP multicast. Performance of PVM using IP multicast over local and wide-area networks is measured and compared with the original unicast implementation. Current limitations of IP multicast are noted.

  1. Sevoflurane Preconditioning Confers Neuroprotection via Anti-apoptosis Effects.

    PubMed

    Wang, Hailian; Shi, Hong; Yu, Qiong; Chen, Jun; Zhang, Feng; Gao, Yanqin

    2016-01-01

    Neuroprotection against cerebral ischemia afforded by volatile anesthetic preconditioning (APC) has been demonstrated both in vivo and in vitro, yet the underlying mechanism is poorly understood. We previously reported that repeated sevoflurane APC reduced infarct size in rats after focal ischemia. In this study, we investigated whether inhibition of apoptotic signaling cascades contributes to sevoflurane APC-induced neuroprotection. Male Sprague-Dawley rats were exposed to ambient air or 2.4 % sevoflurane for 30 min per day for 4 consecutive days and then subjected to occlusion of the middle cerebral artery (MCAO) for 60 min at 24 h after the last sevoflurane intervention. APC with sevoflurane markedly decreased apoptotic cell death in rat brains, which was accompanied by decreased caspase-3 cleavage and cytochrome c release. The apoptotic suppression was associated with increased ratios of anti-apoptotic Bcl-2 family proteins over pro-apoptotic proteins and with decreased activation of JNK and p53 pathways. Thus, our data suggest that suppression of apoptotic cell death contributes to the neuroprotection against ischemic brain injury conferred by sevoflurane preconditioning. PMID:26463923

  2. The natural olive constituent oleuropein induces nutritional cardioprotection in normal and cholesterol-fed rabbits: comparison with preconditioning.

    PubMed

    Andreadou, Ioanna; Benaki, Dimitra; Efentakis, Panagiotis; Bibli, Sofia-Iris; Milioni, Alkistis-Ioanna; Papachristodoulou, Anastasia; Zoga, Anastasia; Skaltsounis, Alexios-Leandros; Mikros, Emmanuel; Iliodromitis, Efstathios K

    2015-06-01

    Ischemic preconditioning, which is mediated by cell signaling molecules, protects the heart from ischemia-reperfusion injury by limiting the infarct size. Oleuropein, the main polyphenolic constituent of olives, reduced the infarct size in normal and cholesterol-fed rabbits when it was administered at a nutritional dose. The aim of the present study was to compare the effects of oleuropein and preconditioning in terms of the cell signaling and metabolism pathways underlying myocardial protection. Rabbits were randomly divided into six groups: the control group received 5?% dextrose for six weeks, the preconditioning group was subjected to two cycles of preconditioning with 5?min ischemia/10?min reperfusion, the O6 group was treated with oleuropein for six weeks, the Chol group was fed a cholesterol-enriched diet and 5?% dextrose for six weeks, and the CholO6 and CholO3 groups were treated with cholesterol and oleuropein for six and three weeks, respectively; oleuropein was dissolved in 5?% dextrose solution and was administered orally at a dose of 20?mg?×?kg(-1)?×?day(-1). All animals were subsequently subjected to 30?min myocardial ischemia followed by 10?min of reperfusion. At that time, myocardial biopsies were taken from the ischemic areas for the assessment of oxidative and nitrosative stress biomarkers (malondialdehyde and nitrotyrosine), and determination of phosphorylation of signaling molecules involved in the mechanism of preconditioning (PI3K, Akt, eNOS, AMPK, STAT3). The tissue extracts NMR metabolic profile was recorded and further analyzed by multivariate statistics. Oxidative biomarkers were significantly reduced in the O6, CholO6, and CholO3 groups compared to the control, preconditioning, and Chol groups. Considering the underlying signaling cascade, the phosphorylation of PI3K, Akt, eNOS, AMPK, and STAT-3 was significantly higher in the preconditioning and all oleuropein-treated groups compared to the control and Chol groups. The NMR-based metabonomic study, performed through the analysis of spectroscopic data, depicted differences in the metabolome of the various groups with significant alterations in purine metabolism. In conclusion, the addition of oleuropein to a normal or hypercholesterolemic diet results in a preconditioning-like intracellular effect, eliminating the deleterious consequences of ischemia and hypercholesterolemia, followed by a decrease of oxidative stress biomarkers. This effect is exerted through inducing preconditioning-involved signaling transduction. Nutritional preconditioning may support the low cardiovascular morbidity and mortality associated with the consumption of olive products. PMID:25473920

  3. Laparoscopic ischemic conditioning of the stomach prior to esophagectomy.

    PubMed

    Yetasook, A K; Leung, D; Howington, J A; Talamonti, M S; Zhao, J; Carbray, J M; Ujiki, M B

    2013-07-01

    Several complications after esophagectomy with gastric pull-up are associated with ischemia within the gastric conduit. The aim of this study is to assess the feasibility of laparoscopic ischemic preconditioning of the stomach prior to thoracotomy, esophagectomy, and gastric pull-up with an intrathoracic anastomosis. A retrospective review of 24 consecutive patients between October 2008 and July 2011 with esophageal adenocarcinoma (stage I-III) undergoing laparoscopic gastric ischemic conditioning prior to esophagectomy was conducted. Conditioning included laparoscopic ligation of the left and short gastric arteries, celiac node dissection, and jejunostomy tube placement. Formal resection and reconstruction was then performed 4-10 days later. Of the 24 patients, 88% received neoadjuvant chemotherapy/radiation therapy. Twenty-three of the 24 patients underwent successful laparoscopic ischemic conditioning and subsequent esophagectomy. Total mean number of lymph nodes harvested was 21.8 (±8.0), and a mean of 5.3 (±2.4) celiac lymph nodes identified. There were no conversions to an open procedure. Length of stay was 3.8 (±4.8) days with a median length of stay of 2 (1-24) days. Three patients experienced anastomotic leak, six patients experience delayed gastric emptying, and two patients developed anastomotic stricture. There were no surgical site infections. R0 resection was achieved in all patients who underwent laparoscopic ischemic conditioning followed by esophagectomy. Laparoscopic ischemic conditioning of the gastric conduit has been shown to be feasible and safe. PMID:22816598

  4. Cerebrospinal fluid from rats given hypoxic preconditioning protects neurons from oxygen-glucose deprivation-induced injury

    PubMed Central

    Zhang, Yan-bo; Guo, Zheng-dong; Li, Mei-yi; Li, Si-jie; Niu, Jing-zhong; Yang, Ming-feng; Ji, Xun-ming; Lv, Guo-wei

    2015-01-01

    Hypoxic preconditioning activates endogenous mechanisms that protect against cerebral ischemic and hypoxic injury. To better understand these protective mechanisms, adult rats were housed in a hypoxic environment (8% O2/92% N2) for 3 hours, and then in a normal oxygen environment for 12 hours. Their cerebrospinal fluid was obtained to culture cortical neurons from newborn rats for 1 day, and then the neurons were exposed to oxygen-glucose deprivation for 1.5 hours. The cerebrospinal fluid from rats subjected to hypoxic preconditioning reduced oxygen-glucose deprivation-induced injury, increased survival rate, upregulated Bcl-2 expression and downregulated Bax expression in the cultured cortical neurons, compared with control. These results indicate that cerebrospinal fluid from rats given hypoxic preconditioning protects against oxygen-glucose deprivation-induced injury by affecting apoptosis-related protein expression in neurons from newborn rats. PMID:26604909

  5. Management of Preconditioned Calves and Impacts of Preconditioning.

    PubMed

    Hilton, W Mark

    2015-07-01

    When studying the practice of preconditioning (PC) calves, many factors need to be examined to determine if cow-calf producers should make this investment. Factors such as average daily gain, feed efficiency, available labor, length of the PC period, genetics, and marketing options must be analyzed. The health sales price advantage is an additional benefit in producing and selling PC calves but not the sole determinant of PC's financially feasibility. Studies show that a substantial advantage of PC is the selling of additional pounds at a cost of gain well below the marginal return of producing those additional pounds. PMID:26139187

  6. Preconditioning’ with Low Dose Lipopolysaccharide Aggravates the Organ Injury / Dysfunction Caused by Hemorrhagic Shock in Rats

    PubMed Central

    Sordi, Regina; Chiazza, Fausto; Patel, Nimesh S. A.; Doyle, Rachel A.; Collino, Massimo; Thiemermann, Christoph

    2015-01-01

    Methods Male rats were ‘pretreated’ with phosphate-buffered saline (PBS; i.p.) or LPS (1 mg/kg; i.p.) 24 h prior to HS. Mean arterial pressure (MAP) was maintained at 30 ± 2 mmHg for 90 min or until 25% of the shed blood had to be re-injected to sustain MAP. This was followed by resuscitation with the remaining shed blood. Four hours after resuscitation, parameters of organ dysfunction and systemic inflammation were assessed. Results HS resulted in renal dysfunction, and liver and muscular injury. At a first glance, LPS preconditioning attenuated organ dysfunction. However, we discovered that HS-rats that had been preconditioned with LPS (a) were not able to sustain a MAP at 30 mmHg for more than 50 min and (b) the volume of blood withdrawn in these animals was significantly less than in the PBS-control group. This effect was associated with an enhanced formation of the nitric oxide (NO) derived from inducible NO synthase (iNOS). Thus, a further control group in which all animals were resuscitated after 50 min of hemorrhage was performed. Then, LPS preconditioning aggravated both circulatory failure and organ dysfunction. Most notably, HS-rats pretreated with LPS exhibited a dramatic increase in NF-?B activation and pro-inflammatory cytokines. Conclusion In conclusion, LPS preconditioning predisposed animals to an earlier vascular decompensation, which may be mediated by an excess of NO production secondary to induction of iNOS and activation of NF-?B. Moreover, LPS preconditioning increased the formation of pro-inflammatory cytokines, which is likely to have contributed to the observed aggravation of organ injury/dysfunction caused by HS. PMID:25830444

  7. Whole-Genome Chromatin IP Sequencing (ChIP-Seq)

    E-print Network

    Kopp, Artyom

    ILLUMINA® SEQUENCING Whole-Genome Chromatin IP Sequencing (ChIP-Seq) Illumina ChIP-Seq combines-associated proteins. Illumina ChIP-Seq technology precisely and cost-effectively maps global binding sites. The powerful Illumina Whole-Genome Chromatin IP Sequencing (ChIP-Seq) application allows researchers to easily

  8. Activation of inositol 1,4,5-trisphosphate receptors during preconditioning low-frequency stimulation suppresses subsequent induction of long-term potentiation in hippocampal CA1 neurons.

    PubMed

    Yamazaki, Y; Fujii, S; Goto, J-I; Fujiwara, H; Mikoshiba, K

    2015-12-17

    We investigated the role of inositol 1,4,5-trisphosphate receptors (IP3Rs) activated during preconditioning low-frequency stimulation (LFS) in the subsequent high-frequency stimulation (HFS)-induced induction of long-term potentiation (LTP) in CA1 neurons in hippocampal slices from mature guinea pigs. Induction of LTP in the field excitatory postsynaptic potential (EPSP) or the population spike (PS) by delivery of HFS (a tetanus of 100 pulses at 100Hz) to the Schaffer collateral-commissural pathway to CA1 neuron synapses was suppressed when the CA1 synapses were preconditioned by LFS of 1000 pulses at 1Hz. This effect was inhibited when the preconditioning LFS was applied in the presence of an N-methyl-d-aspartate receptors (NMDARs) antagonist, a metabotropic glutamate receptor (mGluR) antagonist, IP3R antagonist, a calmodulin-dependent kinase II inhibitor or a calcineurin inhibitor. Furthermore, blockade of group I mGluRs immediately before the delivery of HFS blocked the inhibitory effect of the preconditioning LFS on subsequent induction of LTP by HFS. These results suggest that, in hippocampal CA1 neuron synapses, co-activation of NMDARs and IP3Rs during a preconditioning LFS results in both phosphorylation and dephosphorylation events that lead to prolonged activation of group I mGluRs that is responsible for the failure of LTP induction. PMID:26500182

  9. Vaginal LPS changed gene transcriptional regulation response to ischemic reperfusion and increased vulnerability of fetal brain hemorrhage.

    PubMed

    Dong, Yupeng; Kimura, Yoshitaka; Ito, Takuya; Velayo, Clarissa; Sato, Takafumi; Sugibayashi, Rika; Funamoto, Kiyoe; Hitomi, Kudo; Iida, Keita; Endo, Miyuki; Sato, Naoaki; Yaegashi, Nobuo

    2015-12-01

    During pregnancy, both ischemic reperfusion and bacterial agent LPS are known risk factors for fetal brain damage. However, there is a lack of evidence to explain whether vaginal LPS affects the fetus response to ischemic reperfusion. Here we reported that there was more than 2 folds higher vulnerability of fetal brain hemorrhage response to ischemic reperfusion when mother mouse was treated with vaginal LPS. As our previously reported, ischemic reperfusion induces P53-dependent fetal brain damage was based on a molecular mechanism: the transcriptional pattern was changed from HIF-1alpha-dependent to P53-dependent immediately. In the present work, only with vaginal LPS precondition, phosphorylation of activated transcriptional factor (ATF) 2 at Thr71 appeared in response to ischemic reperfusion. Moreover, this phosphorylation was completely blocked by pre-treatment with a P53 inhibitor, pifithrin-?. We concluded that vaginal LPS precondition trigged the p53-dependent phosphorylation of ATF2 in response to ischemic reperfusion, which played an important role of increasing vulnerability to hemorrhage in fetus. PMID:26523514

  10. Preconditioning in H(div) and Applications

    E-print Network

    the eigenvalues of Jh by (Jh), since the spectral condition number (Jh) := max |(Jh)| min |(Jh)| of the operator Jh is O(h-2 ), we will clearly need to precondition any standard iterative scheme if we want

  11. 40 CFR 1065.518 - Engine preconditioning.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Specified Duty Cycles § 1065.518 Engine preconditioning. (a) This section applies for engines where measured emissions are affected by prior operation, such as with a diesel engine that relies on urea-based...

  12. Role of MicroRNAs in innate neuroprotection mechanisms due to preconditioning of the brain

    PubMed Central

    Jimenez-Mateos, Eva M.

    2015-01-01

    Insults to the brain that are sub-threshold for damage activate endogenous protective pathways, which can temporarily protect the brain against a subsequent harmful episode. This mechanism has been named as tolerance and its protective effects have been shown in experimental models of ischemia and epilepsy. The preconditioning-stimulus can be a short period of ischemia or mild seizures induced by low doses of convulsant drugs. Gene-array profiling has shown that both ischemic and epileptic tolerance feature large-scale gene down-regulation but the mechanism are unknown. MicroRNAs are a class of small non-coding RNAs of ~20–22 nucleotides length which regulate gene expression at a post-transcriptional level via mRNA degradation or inhibition of protein translation. MicroRNAs have been shown to be regulated after non-harmful and harmful stimuli in the brain and to contribute to neuroprotective mechanisms. This review focuses on the role of microRNAs in the development of tolerance following ischemic or epileptic preconditioning. PMID:25954143

  13. The Protective Effect of Remote Renal Preconditioning Against Hippocampal Ischemia Reperfusion Injury: Role of KATP Channels.

    PubMed

    Mehrjerdi, Fatemeh Zare; Aboutaleb, Nahid; Pazoki-Toroudi, Hamidreza; Soleimani, Mansoureh; Ajami, Marjan; Khaksari, Mehdi; Safari, Fatemeh; Habibey, Rouhollah

    2015-12-01

    Remote ischemic preconditioning (RIPC), which consists of several brief ischemia/reperfusion applied at the remote site of lethal ischemia reperfusion, can, through activating different mechanisms, increase the ability of the body's endogenous protection against prolonged ischemia/reperfusion. Recent studies have shown that RIPC has neuroprotective effects, but its mechanisms are not well elucidated. The present study aimed to determine whether activation of KATP channels in remote renal preconditioning decreases hippocampus damage induced by global cerebral ischemia. RIPC was induced by ischemia of the left renal artery (IPC); 24 h later, global cerebral ischemia reperfusion (IR) was induced by common carotid arteries occlusion. 5hydroxydecanoate (5HD) and glibenclamide (Gli) were injected before of IPC. The levels of malondialdehyde (MDA) and catalase (CAT) activity were assessed in hippocampus. Terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) was assessed to detect apoptotic cells in hippocampus. RIPC inhibited apoptosis by decreasing positive TUNEL cells (P?ischemic hippocampus (P?

  14. Platelet-derived microvesicles are involved in cardio-protective effects of remote preconditioning

    PubMed Central

    Ma, Fang; Liu, Hengchao; Shen, Yong; Zhang, Yingjie; Pan, Shaojun

    2015-01-01

    The ischemia-protective mechanism of remote precondition has been a mystery for a long time. Little was known about details of the inter-organ cardio-protective. Microvesicles, also known as microparticles (MPs), are small membrane-vesicles budding from the plasma membrane of cell. Recent studies have indicated MPs to be an important messenger in various biological processes. Our research mainly examined the hypothesis that remote ischemic conditioning can attenuate heart infarction in a rat after they were subjected to 30 min ischemia and 180 min reperfusion (I/R) by MPs. MPs were extracted from three groups of rat: 1) healthy rats, 2) healthy rats that underwent hindlimb ischemia-reperfusion preconditioning (RIPC) immediately, 3) healthy rats that underwent RIPC in 6 hours. Isolated MPs were transfused into rats that had undergone I/R without RIPC. The transfusion of MPs from rats that underwent RIPC immediately resulted in an increase in platelet-derived MPs in blood and reduction in infarction size, confirmed by 2-3-5-triphenyltetrazolium chloride staining. We further observed the contractile function in hearts after they were subjected to different treatments. However, no significant difference was observed in transfusion of MPs from rats that underwent RIPC in 6 hours. RIPC induces an increase in MPs, and platelet-derived MPs may confer at least part of the remote protective effect against cardiac ischemic-reperfusion injury. PMID:26617796

  15. Lrg participates in lipopolysaccharide preconditioning-induced brain ischemia injury via TLR4 signaling pathway.

    PubMed

    Gong, Gu; Bai, Shurong; Wu, Wei; Hu, Ling; Liu, Yinghai; Niu, Jie; Dai, Xuemei; Yin, Liang; Wang, Xiaowu

    2014-09-01

    Lipopolysaccharide (LPS) preconditioning is a powerful neuroprotective phenomenon by which an injurious stimulus renders the brain resistant to a subsequent damaging ischemic insult. The LPS response gene (Lrg) is a recently identified gene in human dental pulp cells treated with LPS. However, the role and mechanism of Lrg in brain ischemia injury have not yet been demonstrated. Here, we sought to determine whether Lrg participates in LPS preconditioning-induced brain ischemia injury. The Lrg protein accumulates in brain tissue after middle cerebral artery occlusion (MCAO). Furthermore, knockdown of Lrg by small interfering RNA (siRNA) significantly increased the infarct size of brain injury. In addition, we investigated the mechanism of Lrg in brain ischemia injury. Lrg-siRNA could regulate inflammatory cytokine expression. Moreover, interleukin-1 receptor-associated kinase 1 (IRAK-1) and nuclear factor Kappa B (NF-?B) p65 protein levels were significantly increased by Lrg-siRNA in mice after MCAO. Conversely, interferon regulatory factor 3 (IRF3) protein level was decreased by Lrg-siRNA. Taken together, these results suggest that Lrg regulates the expression of inflammatory cytokines in LPS preconditioning-induced brain ischemia injury via the toll-like receptor 4 (TLR4) signaling pathway. Lrg may therefore serve as a novel therapeutic target for brain ischemia injury. PMID:24526448

  16. Ischemic Nerve Block.

    ERIC Educational Resources Information Center

    Williams, Ian D.

    This experiment investigated the capability for movement and muscle spindle function at successive stages during the development of ischemic nerve block (INB) by pressure cuff. Two male subjects were observed under six randomly ordered conditions. The duration of index finger oscillation to exhaustion, paced at 1.2Hz., was observed on separate…

  17. Possible role of thromboxane A2 in remote hind limb preconditioning-induced cardioprotection.

    PubMed

    Sharma, Roohani; Randhawa, Puneet Kaur; Singh, Nirmal; Jaggi, Amteshwar Singh

    2016-01-01

    Remote hind limb preconditioning (RIPC) is a protective strategy in which short episodes of ischemia and reperfusion in a remote organ (hind limb) protects the target organ (heart) against sustained ischemic reperfusion injury. The present study was designed to investigate the possible role of thromboxane A2 in RIPC-induced cardioprotection in rats. Remote hind limb preconditioning was performed by four episodes of 5 min of inflation and 5 min of deflation of pressure cuff. Occlusion of the hind limb with blood pressure cuff is most feasible, non-invasive, clinically relevant, and safe method for inducing RIPC. Isolated rat hearts were perfused on Langendorff apparatus and were subjected to global ischemia for 30 min followed by 120-min reperfusion. The levels of lactate dehydrogenase (LDH) and creatine kinase (CK) were measured in coronary effluent to assess the degree of myocardial injury. The extent of myocardial infarct size along with the functional parameters including left ventricular developed pressure (LVDP), dp/dtmax, and dp/dtmin were also measured. Ozagrel (thromboxane synthase inhibitor) and seratrodast (thromboxane A2 receptor antagonist) were employed as pharmacological modulators of thromboxane A2. Remote hind limb preconditioning significantly attenuated ischemia/reperfusion-induced myocardial injury and produced cardioprotective effects. However, administration of ozagrel and seratrodast completely abolished the cardioprotective effects of RIPC suggesting the key role of thromboxane A2 in RIPC-induced cardioprotection. It may be concluded that brief episodes of preconditioning ischemia and reperfusion activates the thromboxane synthase enzyme that produces thromboxane A2, which may elicit cardioprotection either involving humoral or neurogenic pathway. PMID:26531833

  18. Support graph preconditioning for elliptic finite element problems 

    E-print Network

    Wang, Meiqiu

    2009-05-15

    A relatively new preconditioning technique called support graph preconditioning has many merits over the traditional incomplete factorization based methods. A major limitation of this technique is that it is applicable to ...

  19. Effect of Bradykinin Postconditioning on Ischemic and Toxic Brain Damage.

    PubMed

    Lalkovi?ová, Mária; Bonová, Petra; Burda, Jozef; Danielisová, Viera

    2015-08-01

    Brain damage caused by ischemia or toxic agents leads in selectively vulnerable regions to apoptosis-like delayed neuronal death and can result in irreversible damage. Selectively vulnerable neurons of the CA1 area of hippocampus are particularly sensitive to ischemic damage. We investigated the effects of bradykinin (BR) postconditioning on cerebral ischemic and toxic injury. Transient forebrain ischemia was induced by four-vessel occlusion for 10 min and toxic injury was induced by trimethyltin (TMT, 8 µg/kg i.p.). BR as a postconditioner at a dose of 150 µg/kg was applied intraperitoneally 48 h after ischemia or TMT intoxication. Experimental animals were divided into groups according to the length of survival (short-3 and 7 days, and long-28 days survival) and according to the applied ischemic or toxic injury. Glutamate concentration was lowered in both CA1 and dentate gyrus areas of hippocampus after the application of BR postconditioning in both ischemic and toxic brain damage. The number of degenerated neurons in the hippocampal CA1 region was significantly lower in BR-treated ischemic and toxic groups compared to vehicle group. The behavioral test used in our experiments confirms also the memory improvement in conditioned animals. The rats' ability to form spatial maps and learn was preserved, which is visible from our Barnes maze results. By using the methods of delayed postconditioning is possible to stimulate the endogenous protective mechanisms of the organism and induce the neuroprotective effect. In this study we demonstrated that BR postconditioning, if applied before the onset of irreversible neurodegenerative changes, induced neuroprotection against ischemic or toxic injury. PMID:26216051

  20. CISCO IP 7902 FONCTIONS TLPHONIQUES

    E-print Network

    Charette, André

    CISCO IP 7902 FONCTIONS TÉLÉPHONIQUES FONCTIONS DE BASE FAIRE UN APPEL Soulever le combiné et participants. Mettre un terme à une conférence Raccrocher le combiné. . Cisco_IP_7902_FR_CM%207.0_2009324[1].doc 1 de 2 #12;CISCO IP 7902 FONCTIONS TÉLÉPHONIQUES Cisco_IP_7902_FR_CM%207.0_2009324[1].doc 2 de 2

  1. 40 CFR 1065.518 - Engine preconditioning.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., such as with a diesel engine that relies on urea-based selective catalytic reduction. Note that § 1065... cycle specified in 40 CFR 1039.505(b)(1), the second half of the cycle consists of modes three through... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Engine preconditioning....

  2. Revealing Preconditions for Trustful Collaboration in CSCL

    ERIC Educational Resources Information Center

    Gerdes, Anne

    2010-01-01

    This paper analyses preconditions for trust in virtual learning environments. The concept of trust is discussed with reference to cases reporting trust in cyberspace and through a philosophical clarification holding that trust in the form of self-surrender is a common characteristic of all human co-existence. In virtual learning environments,…

  3. Ozone-Oxidative Preconditioning Prevents Doxorubicin-induced Cardiotoxicity in Sprague-Dawley Rats

    PubMed Central

    Delgado-Roche, Livan; Hernández-Matos, Yanet; Medina, Emilio A.; Morejón, Dalia Á.; González, Maité R.; Martínez-Sánchez, Gregorio

    2014-01-01

    Objectives: Induced dilated cardiomyopathy is the main limitation of the anti-cancer drug doxorubicin, which causes oxidative stress and cardiomyocyte death. As ozone therapy can activate the antioxidant systems, this study aimed to investigate the therapeutic efficacy of ozone-oxidative preconditioning against doxorubicin-induced cardiotoxicity. Methods: The study was carried out from September 2013 to January 2014. Sprague-Dawley rats were randomly distributed in the following treatment groups: Group 1 were treated with 2 mg/kg intraperitoneal (i.p.) of doxorubicin twice a week for 50 days; Group 2 were treated with 0.3 mg of ozone/oxygen mixture at 50 ?g/mL of ozone per 6 mL of oxygen by rectal insufflation and then treated with doxorubicin; Group 3 were treated as Group 2 but only with the oxygen, and Group 4 were treated with oxygen first, and then with sodium chloride i.p. as the control group. Results: The results showed that ozone therapy preserved left ventricle morphology which was accompanied by a reduction of serum pro-brain natriuretic peptide levels. The cardioprotective effects of ozone-oxidative preconditioning were associated with a significant increase (P <0.05) of antioxidant enzymes activities and a reduction of lipid and protein oxidation (P <0.05). Conclusion: Ozone-oxidative preconditioning prevents doxorubicin-induced dilated cardiomyopathy through an increase of antioxidant enzymes and a reduction of oxidised macromolecules. This establishes the background for future studies to determine if ozone therapy can be used as a complementary treatment for attenuating doxorubicin-induced cardiotoxicity in cancer patients. PMID:25097769

  4. Non-Coding RNAs as Potential Neuroprotectants against Ischemic Brain Injury

    PubMed Central

    Kaur, Prameet; Liu, Fujia; Tan, Jun Rong; Lim, Kai Ying; Sepramaniam, Sugunavathi; Karolina, Dwi Setyowati; Armugam, Arunmozhiarasi; Jeyaseelan, Kandiah

    2013-01-01

    Over the past decade, scientific discoveries have highlighted new roles for a unique class of non-coding RNAs. Transcribed from the genome, these non-coding RNAs have been implicated in determining the biological complexity seen in mammals by acting as transcriptional and translational regulators. Non-coding RNAs, which can be sub-classified into long non-coding RNAs, microRNAs, PIWI-interacting RNAs and several others, are widely expressed in the nervous system with roles in neurogenesis, development and maintenance of the neuronal phenotype. Perturbations of these non-coding transcripts have been observed in ischemic preconditioning as well as ischemic brain injury with characterization of the mechanisms by which they confer toxicity. Their dysregulation may also confer pathogenic conditions in neurovascular diseases. A better understanding of their expression patterns and functions has uncovered the potential use of these riboregulators as neuroprotectants to antagonize the detrimental molecular events taking place upon ischemic-reperfusion injury. In this review, we discuss the various roles of non-coding RNAs in brain development and their mechanisms of gene regulation in relation to ischemic brain injury. We will also address the future directions and open questions for identifying promising non-coding RNAs that could eventually serve as potential neuroprotectants against ischemic brain injury. PMID:24961318

  5. Protein redox modification as a cellular defense mechanism against tissue ischemic injury.

    PubMed

    Yan, Liang-Jun

    2014-01-01

    Protein oxidative or redox modifications induced by reactive oxygen species (ROS) or reactive nitrogen species (RNS) not only can impair protein function, but also can regulate and expand protein function under a variety of stressful conditions. Protein oxidative modifications can generally be classified into two categories: irreversible oxidation and reversible oxidation. While irreversible oxidation usually leads to protein aggregation and degradation, reversible oxidation that usually occurs on protein cysteine residues can often serve as an "on and off" switch that regulates protein function and redox signaling pathways upon stress challenges. In the context of ischemic tolerance, including preconditioning and postconditioning, increasing evidence has indicated that reversible cysteine redox modifications such as S-sulfonation, S-nitrosylation, S-glutathionylation, and disulfide bond formation can serve as a cellular defense mechanism against tissue ischemic injury. In this review, I highlight evidence of cysteine redox modifications as protective measures in ischemic injury, demonstrating that protein redox modifications can serve as a therapeutic target for attenuating tissue ischemic injury. Prospectively, more oxidatively modified proteins will need to be identified that can play protective roles in tissue ischemic injury, in particular, when the oxidative modifications of such identified proteins can be enhanced by pharmacological agents or drugs that are available or to be developed. PMID:24883175

  6. Income Protection (IP) Insurance 

    E-print Network

    Stokes, Kenneth; Barnaby, G. A. Art; Waller, Mark L.; Outlaw, Joe

    1999-06-09

    stream_source_info pdf_1084.pdf.txt stream_content_type text/plain stream_size 7536 Content-Encoding ISO-8859-1 stream_name pdf_1084.pdf.txt Content-Type text/plain; charset=ISO-8859-1 Income Protection (IP) Insurance... Kenneth Stokes, G.A. ?Art? Barnaby, Mark Waller and Joe Outlaw* The Income Protection (IP) program insures the producer against lost income from reductions in yield or price. This policy pays when the harvested and appraised production to count, multiplied...

  7. A critical review of mechanisms regulating remote preconditioning-induced brain protection.

    PubMed

    Meller, Robert; Simon, Roger P

    2015-11-15

    Remote preconditioning (rPC) is the phenomenon whereby brief organ ischemia evokes an endogenous response such that a different (remote) organ is protected against subsequent, normally injurious ischemia. Experiments show rPC to be effective at evoking cardioprotection against ischemic heart injury and, more recently, neuroprotection against brain ischemia. Such is the enthusiasm for rPC that human studies have been initiated. Clinical trials suggest rPC to be safe (phase II trial) and effective in reducing stroke incidence in a population with high stroke risk. However, despite the therapeutic potential of rPC, there is a large gap in knowledge regarding the effector mechanisms of rPC and how it might be orchestrated to improve outcome after stroke. Here we provide a critical review of mechanisms that are directly attributable to rPC-induced neuroprotection in preclinical trials of rPC. PMID:25953834

  8. Preserving Symmetry in Preconditioned Krylov Subspace Methods

    NASA Technical Reports Server (NTRS)

    Chan, Tony F.; Chow, E.; Saad, Y.; Yeung, M. C.

    1996-01-01

    We consider the problem of solving a linear system Ax = b when A is nearly symmetric and when the system is preconditioned by a symmetric positive definite matrix M. In the symmetric case, one can recover symmetry by using M-inner products in the conjugate gradient (CG) algorithm. This idea can also be used in the nonsymmetric case, and near symmetry can be preserved similarly. Like CG, the new algorithms are mathematically equivalent to split preconditioning, but do not require M to be factored. Better robustness in a specific sense can also be observed. When combined with truncated versions of iterative methods, tests show that this is more effective than the common practice of forfeiting near-symmetry altogether.

  9. Regeneration through autologous hypoxia preconditioned plasma

    PubMed Central

    Hadjipanayi, Ektoras; Schilling, Arndt F

    2014-01-01

    Cellular hypoxic preconditioning is being employed to obtain complex, yet physiological, secretomes rich is angiogenic factors. We previously proposed exposing peripheral blood cells (PBCs) to hypoxic stress stimulation, and demonstrated that controlled release of PBC-derived factor mixtures induces directional microvessel growth in vitro. Hypoxia therefore provides a useful tool for enhancing the angiogenic potential of blood plasma, by generating compositions based on PBCs' natural responses to a wound-like microenvironment. Here, we discuss various methods for preparing and delivering Hypoxia Preconditioned Plasma (HPP), i.e., plasma derived after extracorporeal conditioning of anticoagulated blood under physiological temperature and hypoxia. Special emphasis is given to those approaches that will likely facilitate the clinical translation of HPP-based therapies. We finally draw a comparison between HPP and other, currently available blood-based products, and present the case that its arrival paves the way for developing next-generation autologous therapies toward angiogenesis-supported tissue repair and regeneration. PMID:24831225

  10. M-step preconditioned conjugate gradient methods

    NASA Technical Reports Server (NTRS)

    Adams, L.

    1983-01-01

    Preconditioned conjugate gradient methods for solving sparse symmetric and positive finite systems of linear equations are described. Necessary and sufficient conditions are given for when these preconditioners can be used and an analysis of their effectiveness is given. Efficient computer implementations of these methods are discussed and results on the CYBER 203 and the Finite Element Machine under construction at NASA Langley Research Center are included.

  11. On polynomial preconditioning for indefinite Hermitian matrices

    NASA Technical Reports Server (NTRS)

    Freund, Roland W.

    1989-01-01

    The minimal residual method is studied combined with polynomial preconditioning for solving large linear systems (Ax = b) with indefinite Hermitian coefficient matrices (A). The standard approach for choosing the polynomial preconditioners leads to preconditioned systems which are positive definite. Here, a different strategy is studied which leaves the preconditioned coefficient matrix indefinite. More precisely, the polynomial preconditioner is designed to cluster the positive, resp. negative eigenvalues of A around 1, resp. around some negative constant. In particular, it is shown that such indefinite polynomial preconditioners can be obtained as the optimal solutions of a certain two parameter family of Chebyshev approximation problems. Some basic results are established for these approximation problems and a Remez type algorithm is sketched for their numerical solution. The problem of selecting the parameters such that the resulting indefinite polynomial preconditioners speeds up the convergence of minimal residual method optimally is also addressed. An approach is proposed based on the concept of asymptotic convergence factors. Finally, some numerical examples of indefinite polynomial preconditioners are given.

  12. Effects of morphine and sufentanil preconditioning against myocardial ischemic-reperfusion injury in rabbits

    PubMed Central

    Wang, Xiu-Hong; Zeng, Jian-Feng; Lin, Chao; Chen, Shi-Biao

    2015-01-01

    Objective: This study aims to explore the treatment method of myocardial ischemia-reperfusion injury. Methods: Myocardial Ischemia-reperfusion rabbit model was established in this study. They were divided into four groups: sham operation (S) group, IRI control (I/R) group and IRI with morphine (MF) group and sufentanil (SF). Myocardial infarct size was compared with HE staining method. TUNEL assay was used to detect cell apoptosis. Results: Myocardial infarct size of control group and morphine and sufetanil group was 36.0±3.6, 23.0±1.2 and 27.1±2.3, respectively. There were significant differences between them (P < 0.01). Apoptotic index of I/R, MF and SF groups was 26.9±2.2, 12.5±2.3, 15.8±2.0, with statistical significance (P < 0.05). The concentration of CK-MB in serum: there were no significant differences of CK-MB between each group at baseline. The concentration of CK-MB after reperfusion were higher than that of baseline, except for group S (P < 0.05); Compared with group S, after reperfusion, the CK-MB of other three groups were higher (P < 0.05); The concentration of CK-MB in group MF and SF were lower than group I/R (P < 0.05); In contrast to group MF, the concentration of CK-MB after reperfusion was higher in group SF (P < 0.05). Conclusion: Morphine and sufentanil can specifically protect the myocardial function. PMID:26629064

  13. CXCL10/IP-10

    PubMed Central

    Gotsch, Francesca; Romero, Roberto; Friel, Lara; Kusanovic, Juan Pedro; Espinoza, Jimmy; Erez, Offer; Than, Nandor Gabor; Mittal, Pooja; Edwin, Samuel; Yoon, Bo Hyun; Kim, Chong Jai; Mazaki-Tovi, Shali; Chaiworapongsa, Tinnakorn; Hassan, Sonia S.

    2008-01-01

    OBJECTIVE Interferon (IFN)-? inducible protein, CXCL10/IP-10, is a member of the CXC chemokine family with pro-inflammatory and anti-angiogenic properties. This chemokine has been proposed to be a key link between inflammation and angiogenesis. The aim of this study was to determine whether preeclampsia and delivery of a small for gestational age (SGA) neonate are associated with changes in maternal serum concentration of CXCL10/IP-10. STUDY DESIGN This cross-sectional study included patients in the following groups: (1) non pregnant women (N=49); (2) women with normal pregnancies (N=89); (3) patients with preeclampsia (N=100); and (4) patients who delivered an SGA neonate (N=78). SGA was defined as birth weight below the 10th percentile. Maternal serum concentrations of CXCL10/IP-10 were measured by sensitive immunoassay. Non-parametric statistics were used for analysis. RESULTS (1) Patients with normal pregnancies had a significantly higher median serum concentration of CXCL10/IP-10 than non-pregnant women (median: 116.1 pg/mL, range: 40.7-1314.3 vs. median: 90.3 pg/mL, range: 49.2-214.7, respectively; p=0.002); (2) no significant correlation was found between maternal serum concentration of CXCL10/IP-10 and gestational age (between 19 and 38 weeks); (3) there were no differences in median serum CXCL10/IP-10 concentrations between patients who delivered an SGA neonate and those with normal pregnancies (median: 122.4 pg/mL, range: 37.3-693.5 vs. median: 116.1 pg/mL, range: 40.7-1314.3, respectively; p>0.05); (4) patients with preeclampsia had a higher median serum concentration of CXCL10/IP-10 than normal pregnant women (median: 156.4 pg/mL, range: 47.4-645.9 vs. median: 116.1 pg/mL, range: 40.7-1314.3, respectively; p<0.05); (5) patients with preeclampsia had a higher median concentration of CXCL10/IP-10 than those who delivered an SGA neonate (median: 156.4 pg/mL, range: 47.4-645.9 vs. median: 122.4 pg/mL, range: 37.3-693.5, respectively; p<0.05). CONCLUSIONS Patients with preeclampsia have significantly higher serum concentrations of CXCL10/IP-10 than both normal pregnant women and mothers who have SGA neonates. These results are likely to reflect an anti-angiogenic state as well as an enhanced systemic inflammatory response in patients with preeclampsia. Alternatively, since preeclampsia and SGA share several mechanisms of disease, it is possible that a higher concentration of this chemokine may contribute to the clinical presentation of preeclampsia in patients with a similar intrauterine insult. PMID:17943641

  14. Advanced Networking Voice over IP

    E-print Network

    Lo Cigno, Renato Antonio

    goal is ­ "How to find SIP services" · The preferred solution is DNS based: the answer tells the IP services #12;5 Renato.LoCigno@dit.unitn.it Advanced Networking ­ VoIP - 2 13 How to find SIP services1 Advanced Networking Voice over IP & Other Multimedia Protocols Some SIP Advanced Topics Renato Lo

  15. Advanced Networking Voice over IP

    E-print Network

    Lo Cigno, Renato Antonio

    goal is ­ "How to find SIP services" · The preferred solution is DNS based: the answer tells the IP services #12;Renato.LoCigno@dit.unitn.it Advanced Networking ­ VoIP - 2 13 How to find SIP servicesAdvanced Networking Voice over IP & Other Multimedia Protocols Some SIP Advanced Topics Renato Lo

  16. Preconditioning and the limit to the incompressible flow equations

    NASA Technical Reports Server (NTRS)

    Turkel, E.; Fiterman, A.; Vanleer, B.

    1993-01-01

    The use of preconditioning methods to accelerate the convergence to a steady state for both the incompressible and compressible fluid dynamic equations are considered. The relation between them for both the continuous problem and the finite difference approximation is also considered. The analysis relies on the inviscid equations. The preconditioning consists of a matrix multiplying the time derivatives. Hence, the steady state of the preconditioned system is the same as the steady state of the original system. For finite difference methods the preconditioning can change and improve the steady state solutions. An application to flow around an airfoil is presented.

  17. Forbidding Preconditions and Ordered Abstraction Hierarchies Eugene Fink \\Lambda

    E-print Network

    Fink, Eugene

    Forbidding Preconditions and Ordered Abstraction Hierarchies Eugene Fink \\Lambda School of Computer Science Carnegie Mellon University Pittsbugrh, PA 15213 eugene@cs.cmu.edu Qiang Yang \\Lambda Department

  18. Approximate polynomial preconditioning applied to biharmonic equations on vector supercomputers

    NASA Technical Reports Server (NTRS)

    Wong, Yau Shu; Jiang, Hong

    1987-01-01

    Applying a finite difference approximation to a biharmonic equation results in a very ill-conditioned system of equations. This paper examines the conjugate gradient method used in conjunction with the generalized and approximate polynomial preconditionings for solving such linear systems. An approximate polynomial preconditioning is introduced, and is shown to be more efficient than the generalized polynomial preconditionings. This new technique provides a simple but effective preconditioning polynomial, which is based on another coefficient matrix rather than the original matrix operator as commonly used.

  19. Effect of atropine and gammahydroxybutyrate on ischemically induced changes in the level of radioactivity in (/sup 3/H)inositol phosphates in gerbil brain in vivo

    SciTech Connect

    Wikiel, H.; Halat, G.; Strosznajder, J.

    1988-05-01

    Brain ischemia in gerbils was induced by ligation of both common carotid arteries for 1 min or 10 min. Sham-operated animals served as controls. Intracerebral injection of (3H)inositol into gerbil brain 16 hr before ischemic insult resulted in equilibration of the label between inositol lipids and water-soluble inositol phosphate. A short ischemic period (1 min) resulted in a statistically significant increase in the radioactivity of inositol triphosphate (IP3) and inositol monophosphate (IP), by about 48% and 79%, respectively, with little change in that of the intermediate inositol biphosphate (IP2), which increased by about 16%. When the ischemic period was prolonged (10 min), an increase in the radioactivity of inositol monophosphate exclusively, by about 84%, was observed. The level of radioactivity in inositol phosphates IP2 and IP3 decreased by about 50%, probably as a consequence of phosphatase activation by the ischemic insult. The agonist of the cholinergic receptor, carbachol, injected intracerebrally (40 micrograms per animal) increased accumulation of radioactivity in all inositol phosphates. The level of radioactivity in IP3, IP2, and IP was elevated by about 40, 23, and 147%, respectively. The muscarinic cholinergic antagonist, atropine, injected intraperitoneally in doses of 100 mg/kg body wt. depressed phosphoinositide metabolism in control animals. The level of radioactivity in water-soluble inositol metabolites in the brain of animals pretreated with atropine was evidently about 32% lower than in untreated animals. Pretreatment with atropine decreased the radioactivity of all inositol phosphates in the brain of animals subjected to 1-min ischemia and the radioactivity of IP in the case of 10-min brain ischemia.

  20. Hypoxic Preconditioning Differentially Affects GABAergic and Glutamatergic Neuronal Cells in the Injured Cerebellum of the Neonatal Rat

    PubMed Central

    Patterson, Sean I.; Muñoz, Estela M.; Seltzer, Alicia M.

    2014-01-01

    In this study we examined cerebellar alterations in a neonatal rat model of hypoxic-ischemic brain injury with or without hypoxic preconditioning (Pc). Between postnatal days 7 and 15, the cerebellum is still undergoing intense cellular proliferation, differentiation and migration, dendritogenesis and synaptogenesis. The expression of glutamate decarboxylase 1 (GAD67) and the differentiation factor NeuroD1 were examined as markers of Purkinje and granule cells, respectively. We applied quantitative immunohistochemistry to sagittal cerebellar slices, and Western blot analysis of whole cerebella obtained from control (C) rats and rats submitted to Pc, hypoxia-ischemia (L) and a combination of both treatments (PcL). We found that either hypoxia-ischemia or Pc perturbed the granule cells in the posterior lobes, affecting their migration and final placement in the internal granular layer. These effects were partially attenuated when the Pc was delivered prior to the hypoxia-ischemia. Interestingly, whole nuclear NeuroD1 levels in Pc animals were comparable to those in the C rats. However, a subset of Purkinje cells that were severely affected by the hypoxic-ischemic insult—showing signs of neuronal distress at the levels of the nucleus, cytoplasm and dendritic arborization—were not protected by Pc. A monoclonal antibody specific for GAD67 revealed a three-band pattern in cytoplasmic extracts from whole P15 cerebella. A ?110 kDa band, interpreted as a potential homodimer of a truncated form of GAD67, was reduced in Pc and L groups while its levels were close to the control animals in PcL rats. Additionally we demonstrated differential glial responses depending on the treatment, including astrogliosis in hypoxiated cerebella and a selective effect of hypoxia-ischemia on the vimentin-immunolabeled intermediate filaments of the Bergmann glia. Thus, while both glutamatergic and GABAergic cerebellar neurons are compromised by the hypoxic-ischemic insult, the former are protected by a preconditioning hypoxia while the latter are not. PMID:25032984

  1. Preconditioning cortical lesions reduce the incidence of peri-infarct depolarizations during focal ischemia in the Spontaneously Hypertensive Rat: interaction with prior anesthesia and the impact of hyperglycemia.

    PubMed

    Zhao, Liang; Nowak, Thaddeus S

    2015-07-01

    The relationship between peri-infarct depolarizations (PIDs) and infarction was investigated in a model of preconditioning by cortical freeze lesions (cryogenic lesions, CL) in the Spontaneously Hypertensive Rat. Small (< 5 mm(3)) lesions produced 24 hours before permanent focal ischemia were protective, without impacting baseline cerebral blood flow (CBF) and metabolism. Prior CL reduced infarct volume, associated with improved penumbral CBF as previously showed for ischemic preconditioning. The brief initial procedure avoided sham effects on infarct volume after subsequent occlusion under brief anesthesia. However, under prolonged isoflurane anesthesia for perfusion monitoring both sham and CL rats showed reduced PID incidence relative to naive animals. This anesthesia effect could be eliminated by using ?-chloralose during perfusion imaging. As an additional methodological concern, blood glucose was frequently elevated at the time of the second surgery, reflecting buprenorphine-induced pica and other undefined mechanisms. Even modest hyperglycemia (>10 mmol/L) reduced PID incidence. In normoglycemic animals CL preconditioning reduced PID number by 50%, demonstrating associated effects on PID incidence, penumbral perfusion, and infarct progression. Hyperglycemia suppressed PIDs without affecting the relationship between CBF and infarction. This suggests that the primary effect of preconditioning is to improve penumbral perfusion, which in turn impacts PID incidence and infarct size. PMID:25757750

  2. Rational modulation of the innate immune system for neuroprotection in ischemic stroke

    PubMed Central

    Amantea, Diana; Micieli, Giuseppe; Tassorelli, Cristina; Cuartero, María I.; Ballesteros, Iván; Certo, Michelangelo; Moro, María A.; Lizasoain, Ignacio; Bagetta, Giacinto

    2015-01-01

    The innate immune system plays a dualistic role in the evolution of ischemic brain damage and has also been implicated in ischemic tolerance produced by different conditioning stimuli. Early after ischemia, perivascular astrocytes release cytokines and activate metalloproteases (MMPs) that contribute to blood–brain barrier (BBB) disruption and vasogenic oedema; whereas at later stages, they provide extracellular glutamate uptake, BBB regeneration and neurotrophic factors release. Similarly, early activation of microglia contributes to ischemic brain injury via the production of inflammatory cytokines, including tumor necrosis factor (TNF) and interleukin (IL)-1, reactive oxygen and nitrogen species and proteases. Nevertheless, microglia also contributes to the resolution of inflammation, by releasing IL-10 and tumor growth factor (TGF)-?, and to the late reparative processes by phagocytic activity and growth factors production. Indeed, after ischemia, microglia/macrophages differentiate toward several phenotypes: the M1 pro-inflammatory phenotype is classically activated via toll-like receptors or interferon-?, whereas M2 phenotypes are alternatively activated by regulatory mediators, such as ILs 4, 10, 13, or TGF-?. Thus, immune cells exert a dualistic role on the evolution of ischemic brain damage, since the classic phenotypes promote injury, whereas alternatively activated M2 macrophages or N2 neutrophils prompt tissue remodeling and repair. Moreover, a subdued activation of the immune system has been involved in ischemic tolerance, since different preconditioning stimuli act via modulation of inflammatory mediators, including toll-like receptors and cytokine signaling pathways. This further underscores that the immuno-modulatory approach for the treatment of ischemic stroke should be aimed at blocking the detrimental effects, while promoting the beneficial responses of the immune reaction. PMID:25972779

  3. H(curl) Auxiliary Mesh Preconditioning

    SciTech Connect

    Kolev, T V; Pasciak, J E; Vassilevski, P S

    2006-08-31

    This paper analyzes a two-level preconditioning scheme for H(curl) bilinear forms. The scheme utilizes an auxiliary problem on a related mesh that is more amenable for constructing optimal order multigrid methods. More specifically, we analyze the case when the auxiliary mesh only approximately covers the original domain. The latter assumption is important since it allows for easy construction of nested multilevel spaces on regular auxiliary meshes. Numerical experiments in both two and three space dimensions illustrate the optimal performance of the method.

  4. 40 CFR 86.132-00 - Vehicle preconditioning.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Vehicle preconditioning. 86.132-00 Section 86.132-00 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... manufacturer has concerns about fuel effects on adaptive memory systems, a manufacturer may precondition a...

  5. [STRESS AND INFARCT LIMITING EFFECTS OF EARLY HYPOXIC PRECONDITIONING].

    PubMed

    Lishmanov, Yu B; Maslov, L N; Sementsov, A S; Naryzhnaya, N V; Tsibulnikov, S Yu

    2015-09-01

    It was established that early hypoxic preconditioning is an adaptive state different from eustress and distress. Hypoxic preconditioning has the cross effects, increasing the tolerance of the heart to ischemia-reperfusion and providing antiulcerogenic effect during immobilization stress. PMID:26672158

  6. A preconditioned formulation of the Cauchy-Riemann equations

    NASA Technical Reports Server (NTRS)

    Phillips, T. N.

    1983-01-01

    A preconditioning of the Cauchy-Riemann equations which results in a second-order system is described. This system is shown to have a unique solution if the boundary conditions are chosen carefully. This choice of boundary condition enables the solution of the first-order system to be retrieved. A numerical solution of the preconditioned equations is obtained by the multigrid method.

  7. Modeling oxygen requirements in ischemic cardiomyocytes

    E-print Network

    McDougal, Anthony Drew

    2015-01-01

    Ischemic heart disease remains a leading cause of death globally and in the US. The most common ischemic event is a heart attack, where one or more arteries are obstructed and the cardiac muscle is deprived of oxygen. ...

  8. Involvement of SIRT1 in hypoxic down-regulation of c-Myc and ?-catenin and hypoxic preconditioning effect of polyphenols

    SciTech Connect

    Hong, Kyung-Soo; Research Center for Ischemic Tissue regeneration, Pusan National University School of Medicine, Yangsan ; Park, Jun-Ik; Kim, Mi-Ju; Kim, Hak-Bong; Lee, Jae-Won; Research Center for Ischemic Tissue regeneration, Pusan National University School of Medicine, Yangsan ; Dao, Trong Tuan; Oh, Won Keun; Kang, Chi-Dug; Kim, Sun-Hee; Research Center for Ischemic Tissue regeneration, Pusan National University School of Medicine, Yangsan

    2012-03-01

    SIRT1 has been found to function as a Class III deacetylase that affects the acetylation status of histones and other important cellular nonhistone proteins involved in various cellular pathways including stress responses and apoptosis. In this study, we investigated the role of SIRT1 signaling in the hypoxic down-regulations of c-Myc and ?-catenin and hypoxic preconditioning effect of the red wine polyphenols such as piceatannol, myricetin, quercetin and resveratrol. We found that the expression of SIRT1 was significantly increased in hypoxia-exposed or hypoxic preconditioned HepG2 cells, which was closely associated with the up-regulation of HIF-1? and down-regulation of c-Myc and ?-catenin expression via deacetylation of these proteins. In addition, blockade of SIRT1 activation using siRNA or amurensin G, a new potent SIRT1 inhibitor, abolished hypoxia-induced HIF-1? expression but increased c-Myc and ?-catenin expression. SIRT1 was also found to stabilize HIF-1? protein and destabilize c-Myc, ?-catenin and PHD2 under hypoxia. We also found that myricetin, quercetin, piceatannol and resveratrol up-regulated HIF-1? and down-regulated c-Myc, PHD2 and ?-catenin expressions via SIRT1 activation, in a manner that mimics hypoxic preconditioning. This study provides new insights of the molecular mechanisms of hypoxic preconditioning and suggests that polyphenolic SIRT1 activators could be used to mimic hypoxic/ischemic preconditioning. -- Graphical abstract: Polyphenols mimicked hypoxic preconditioning by up-regulating HIF-1? and SIRT1 and down-regulating c-Myc, PHD2, and ?-catenin. HepG2 cells were pretreated with the indicated doses of myricetin (MYR; A), quercetin (QUR; B), or piceatannol (PIC; C) for 4 h and then exposed to hypoxia for 4 h. Levels of HIF-1?, SIRT1, c-Myc, ?-catenin, and PHD2 were determined by western blot analysis. The data are representative of three individual experiments. Highlights: ? SIRT1 expression is increased in hypoxia-exposed or hypoxic preconditioned cells. ? SIRT1 deacetylates c-Myc and ?-catenin ? HIF-1? is up-regulated by down-regulation of c-Myc and ?-catenin expression. ? Polyphenolic SIRT1 activators mimics hypoxic preconditioning.

  9. Ischemic and postischemic conditioning of the myocardium in clinical practice: challenges, expectations and obstacles.

    PubMed

    Iliodromitis, Efstathios K; Andreadou, Ioanna; Iliodromitis, Konstantinos; Dagres, Nikolaos

    2014-01-01

    Conditioning refers to endogenous mechanisms rendering the myocardium more tolerant against reperfusion injury. Application of brief ischemia-reperfusion cycles prior to the index ischemia has a beneficial effect and limits the infarct size. This is called preconditioning and is mainly mediated by activation of adenosine, bradykinin, opioid and other receptors, with subsequent activation of intracellular mediators leading to mitochondrial protection. A clinical equivalent of preconditioning is preinfarction angina. Benefits for the ischemic and reperfused myocardium are also provided by repetitive short-lived cycles of ischemia-reperfusion applied after the index ischemia. This is termed postconditioning, shares a common pathway with preconditioning, and is more useful and relevant in clinical practice. Finally, benefits are also derived from remote conditioning, i.e. ischemia applied in a remote vascular territory parallel with or immediately after the index myocardial ischemia. Several pharmacological interventions may interfere with these mechanisms leading to enhanced protection of the myocardium and limitation of the infarct size. Despite the huge interest and the great body of evidence that verify the effectiveness of conditioning, clinical application has remained limited due to controversies over the appropriate intervention protocol, but also interference of medication, comorbidities and other factors that may enhance or blur the protective effect. PMID:25227478

  10. Ischemic penumbra in acute stroke: Demonstration by PET with fluorine-18 fluoromisonidazole

    SciTech Connect

    Yeh, S.H.; Liu, R.S.; Hu, H.H.

    1994-05-01

    Ischemic penumbra (IP) in acute stroke has gained clinical interest since tissue functions may be recovered if perfusion can be reestablished. However, such therapeutic intervention is {open_quotes}blind{close_quotes} since clinical examination can not distinguish IP from developing infarction. In vivo demonstration of IP may have significance for stroke patient management. This study was a preliminary evaluation of detecting IP in vivo by F-18 fluoromisonidazole ([F-18]-FMISO), a hypoxic imaging agent. Static PET imaging was performed after IV injection of 370 MBq of [F-18]-FMISO at 20 and 120 min. Tomograms were reconstructed and evaluated visually in correlation with CT or MR scans. In acute stroke, patients (pts) were called back for the second PET study one month after the initial study. CT was used for confirming infarction. In 6 pts with acute cerebral infarction, three of them had intense [F-18]-FMISO retention in the penumbra surrounding the central, eclipse-like zone of absent radio-activity (infarction) at 2 hr in the acute state, and the penumbra disappeared in association with increased area of infarction on CT in one case in the chronic state. In five pts with chronic infarction, all had no penumbra of [F-18]-FMISO retention. In summary, our preliminary results demonstrate the feasibility of using [F-18]-FMISO PET to detect ischemic penumbra in vivo.

  11. Myocardial Hypertrophic Preconditioning Attenuates Cardiomyocyte Hypertrophy and Slows Progression to Heart Failure Through Upregulation of S100A8/A9

    PubMed Central

    Wei, Xuan; Wu, Bing; Zhao, Jing; Zeng, Zhi; Xuan, Wanling; Cao, Shiping; Huang, Xiaobo; Asakura, Masanori; Xu, Dingli; Bin, Jianping; Kitakaze, Masafumi

    2015-01-01

    Background— Transient preceding brief ischemia provides potent cardioprotection against subsequent long ischemia, termed ischemic preconditioning. Here, we hypothesized that transient short-term hypertrophic stimulation would induce the expression of hypertrophy regression genes and render the heart resistant to subsequent hypertrophic stress, and slow the progression to heart failure, as well. Methods and Results— Cardiomyocyte hypertrophy was induced in mice by either transverse aortic constriction or an infusion of phenylephrine, and in neonatal rat ventricular cardiomyocytes by norepinephrine exposures. In the preconditioning groups, hypertrophic stimulation was provided for 1 to 7 days and then withdrawn for several days by either aortic debanding or discontinuing phenylephrine or norepinephrine treatment, followed by subsequent reexposure to the hypertrophic stimulus for the same period as in the control group. One or 6 weeks after transverse aortic constriction, the heart weight/body weight ratio was lower in the preconditioning group than in the control group, whereas the lung weight/body weight ratio was significantly decreased 6 weeks after transverse aortic constriction. Similar results were obtained in mice receiving phenylephrine infusion and neonatal rat ventricular cardiomyocytes stimulated with norepinephrine. Both mRNA and protein expression of S100A8 and S100A9 showed significant upregulation after the removal of hypertrophic stimulation and persisted for 6 weeks in response to reimposition of transverse aortic constriction. The treatment with recombinant S100A8/A9 inhibited norepinephrine-induced myocyte hypertrophy and reduced the expression of calcineurin and NFATc3, but the silencing of S100A8/A9 prevented such changes. Conclusions— Preconditioning with prohypertrophic factors exerts an antihypertrophic effect and slows the progression of heart failure, indicating the existence of the phenomenon for hypertrophic preconditioning. PMID:25820336

  12. Intravenous transplantation of mesenchymal stem cells preconditioned with early phase stroke serum: current evidence and study protocol for a randomized trial

    PubMed Central

    2013-01-01

    Background Recovery after a major stroke is usually limited, but cell therapy for patients with fixed neurologic deficits is emerging. Several recent clinical trials have investigated mesenchymal stem cell (MSC) therapy for patients with ischemic stroke. We previously reported the results of a controlled trial on the application of autologous MSCs in patients with ischemic stroke with a long-term follow-up of up to 5 years (the 'STem cell Application Researches and Trials In NeuroloGy’ (STARTING) study). The results from this pilot trial are challenging, but also raise important issues. In addition, there have been recent efforts to improve the safety and efficacy of MSC therapy for stroke. Methods and design The clinical and preclinical background and the STARTING-2 study protocol are provided. The trial is a prospective, randomized, open-label, blinded-endpoint (PROBE) clinical trial. Both acute and chronic stroke patients will be selected based on clinical and radiological features and followed for 3 months after MSC treatment. The subjects will be randomized into one of two groups: (A) a MSC group (n = 40) or (B) a control group (n = 20). Autologous MSCs will be intravenously administered after ex vivo culture expansion with autologous ischemic serum obtained as early as possible, to enhance the therapeutic efficacy (ischemic preconditioning). Objective outcome measurements will be performed using multimodal MRI and detailed functional assessments by blinded observers. Discussion This trial is the first to evaluate the efficacy of MSCs in patients with ischemic stroke. The results may provide better evidence for the effectiveness of MSC therapy in patients with ischemic stroke. Trial registration This trial was registered with ClinicalTrials.gov, number NCT01716481. PMID:24083670

  13. Hypobaric Preconditioning Modifies Group I mGluRs Signaling in Brain Cortex.

    PubMed

    Semenov, Dmitry G; Belyakov, Alexandr V; Glushchenko, Tatjana S; Samoilov, Mikhail O; Salinska, Elzbieta; Lazarewicz, Jerzy W

    2015-11-01

    The study assessed involvement of Ca(2+) signaling mediated by the metabotropic glutamate receptors mGluR1/5 in brain tolerance induced by hypoxic preconditioning. Acute slices of rat piriform cortex were tested 1 day after exposure of adult rats to mild hypobaric hypoxia for 2 h at a pressure of 480 hPa once a day for three consecutive days. We detected 44.1 ± 11.6 % suppression of in vitro anoxia-induced increases of intracellular Ca(2+) levels and a fivefold increase in Ca(2+) transients evoked by selective mGluR1/5 agonist, DHPG. Western blot analysis of cortical homogenates demonstrated a 11 ± 4 % decrease in mGluR1 immunoreactivity (IR), and in the nuclei-enriched fraction a 12 ± 3 % increase in IR of phospholipase C?1 (PLC?1), which is a major mediator of mGluR1/5 signaling. Immunocytochemical analysis of the cortex revealed increase in the mGluR1/5 and PLC?1 IR in perikarya, and a decrease in IR of the neuronal inositol trisphosphate receptors (IP3Rs). We suggest that enhanced expression of mGluR5 and PLC?1 and potentiation of Ca(2+) signaling may represent pro-survival upregulation of Ca(2+)-dependent genomic processes, while decrease in mGluR1 and IP3R IR may be attributed to a feedback mechanism preventing excessive intracellular Ca(2+) release. PMID:26318863

  14. Remote ischaemic preconditioning for coronary artery bypass grafting

    PubMed Central

    Benstoem, Carina; Stoppe, Christian; Liakopoulos, Oliver J; Meybohm, Patrick; Clayton, Tim C; Yellon, Derek M; Hausenloy, Derek J; Goetzenich, Andreas

    2015-01-01

    This is the protocol for a review and there is no abstract. The objectives are as follows: To assess the benefits and harms of remote ischaemic preconditioning in patients undergoing coronary artery bypass grafting, with or without valve surgery.

  15. Preconditioning methods for improved convergence rates in iterative reconstructions

    SciTech Connect

    Clinthorne, N.H.; Chiao, Pingchun; Rogers, W.L. . Div. of Nuclear Medicine); Pan, T.S. . Dept. of Nuclear Medicine); Stamos, J.A. . Dept. of Nuclear Engineering)

    1993-03-01

    Because of the characteristics of the tomographic inversion problem, iterative reconstruction techniques often suffer from poor convergence rates--especially at high spatial frequencies. By using preconditioning methods, the convergence properties of most iterative methods can be greatly enhanced without changing their ultimate solution. To increase reconstruction speed, the authors have applied spatially-invariant preconditioning filters that can be designed using the tomographic system response and implemented using 2-D frequency-domain filtering techniques. In a sample application, the authors performed reconstructions from noiseless, simulated projection data, using preconditioned and conventional steepest-descent algorithms. The preconditioned methods demonstrated residuals that were up to a factor of 30 lower than the unassisted algorithms at the same iteration. Applications of these methods to regularized reconstructions from projection data containing Poisson noise showed similar, although not as dramatic, behavior.

  16. 40 CFR 1065.516 - Sample system decontamination and preconditioning.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...PROCEDURES Performing an Emission Test Over Specified Duty Cycles § 1065.516 Sample system decontamination and preconditioning...measure hydrocarbon and PM emissions by sampling purified air or nitrogen. (3) When calculating zero emission levels, apply...

  17. Preconditioning Outside Air: Cooling Loads from Building Ventilation 

    E-print Network

    Kosar, D.

    1998-01-01

    of the standard. To mitigate or nullify these additional weather loads, outdoor air preconditioning technologies are being promoted in combination with conventional HVAC operations downstream as a means to deliver the required fresh air and control humidity...

  18. PRECONDITIONING FOR THE MIXED FORMULATION OF LINEAR PLANE A Dissertation

    E-print Network

    Wang, Yanqiu

    as to style and content by: Joseph E. Pasciak (Chair of Committee) James H. Bramble (Member) Raytcho Lazarov thank Dr. James H. Bramble for his inspiring lectures on finite element methods and preconditioning

  19. A SUBSPACE PRECONDITIONING ALGORITHM FOR EIGENVECTOR/EIGENVALUE COMPUTATION

    E-print Network

    Pasciak, Joseph

    A SUBSPACE PRECONDITIONING ALGORITHM FOR EIGENVECTOR/EIGENVALUE COMPUTATION James H. Bramble, Cornell University. Typeset by A M S­T E X 1 #12; 2 BRAMBLE, ET. AL. We consider the case where the first

  20. Effective matrix-free preconditioning for the augmented immersed ...

    E-print Network

    2015-09-05

    Sep 5, 2015 ... The immersed interface method can then be applied conveniently with a fast. Poisson solver .... Thus, the preconditioning cost is negligible as compared with the matrix- ...... and an external forcing term, respectively. There is a ...

  1. Sevoflurane Preconditioning Reduces Intestinal Ischemia-Reperfusion Injury: Role of Protein Kinase C and Mitochondrial ATP-Sensitive Potassium Channel

    PubMed Central

    Shen, Zhiwen; Miao, Liping; Zhang, Kun; Wang, Fei; Li, Yujuan

    2015-01-01

    Ischemic preconditioning (IPC) has been considered to be a potential therapy to reduce ischemia-reperfusion injury (IRI) since the 1980s. Our previous study indicated that sevoflurane preconditioning (SPC) also reduced intestinal IRI in rats. However, whether the protective effect of SPC is similar to IPC and the mechanisms of SPC are unclear. Thus, we compared the efficacy of SPC and IPC against intestinal IRI and the role of protein kinase C (PKC) and mitochondrial ATP-sensitive potassium channel (mKATP) in SPC. A rat model of intestinal IRI was used in this study. The superior mesenteric artery (SMA) was clamped for 60 min followed by 120 min of reperfusion. Rats with IPC underwent three cycles of SMA occlusion for 5 min and reperfusion for 5 min before intestinal ischemia. Rats with SPC inhaled sevoflurane at 0.5 minimum alveolar concentration (MAC) for 30 min before the intestinal ischemic insult. Additionally, the PKC inhibitor Chelerythrine (CHE) or mKATP inhibitor 5-Hydroxydecanoic (5-HD) was injected intraperitoneally before sevoflurane inhalation. Both SPC and IPC ameliorated intestinal IRI-induced histopathological changes, decreased Chiu’s scores, reduced terminal deoxyribonucleotide transferase-mediated dUTP nick end labeling (TUNEL) positive cells in the epithelium, and inhibited the expression of malondialdehyde (MDA) and tumor necrosis factor-? (TNF-?). These protective effects of SPC were similar to those of IPC. Pretreatment with PKC or mKATP inhibitor abolished SPC—induced protective effects by increasing Chiu’s scores, down-regulated the expression of Bcl-2 and activated caspase-3. Our results suggest that pretreatment with 0.5 MAC sevoflurane is as effective as IPC against intestinal IRI. The activation of PKC and mKATP may be involved in the protective mechanisms of SPC. PMID:26505750

  2. Sevoflurane Preconditioning Reduces Intestinal Ischemia-Reperfusion Injury: Role of Protein Kinase C and Mitochondrial ATP-Sensitive Potassium Channel.

    PubMed

    Liu, Chuiliang; Liu, Yanhui; Shen, Zhiwen; Miao, Liping; Zhang, Kun; Wang, Fei; Li, Yujuan

    2015-01-01

    Ischemic preconditioning (IPC) has been considered to be a potential therapy to reduce ischemia-reperfusion injury (IRI) since the 1980s. Our previous study indicated that sevoflurane preconditioning (SPC) also reduced intestinal IRI in rats. However, whether the protective effect of SPC is similar to IPC and the mechanisms of SPC are unclear. Thus, we compared the efficacy of SPC and IPC against intestinal IRI and the role of protein kinase C (PKC) and mitochondrial ATP-sensitive potassium channel (mKATP) in SPC. A rat model of intestinal IRI was used in this study. The superior mesenteric artery (SMA) was clamped for 60 min followed by 120 min of reperfusion. Rats with IPC underwent three cycles of SMA occlusion for 5 min and reperfusion for 5 min before intestinal ischemia. Rats with SPC inhaled sevoflurane at 0.5 minimum alveolar concentration (MAC) for 30 min before the intestinal ischemic insult. Additionally, the PKC inhibitor Chelerythrine (CHE) or mKATP inhibitor 5-Hydroxydecanoic (5-HD) was injected intraperitoneally before sevoflurane inhalation. Both SPC and IPC ameliorated intestinal IRI-induced histopathological changes, decreased Chiu's scores, reduced terminal deoxyribonucleotide transferase-mediated dUTP nick end labeling (TUNEL) positive cells in the epithelium, and inhibited the expression of malondialdehyde (MDA) and tumor necrosis factor-? (TNF-?). These protective effects of SPC were similar to those of IPC. Pretreatment with PKC or mKATP inhibitor abolished SPC-induced protective effects by increasing Chiu's scores, down-regulated the expression of Bcl-2 and activated caspase-3. Our results suggest that pretreatment with 0.5 MAC sevoflurane is as effective as IPC against intestinal IRI. The activation of PKC and mKATP may be involved in the protective mechanisms of SPC. PMID:26505750

  3. Ischemic conditioning-induced endogenous brain protection: Applications pre-, per- or post-stroke.

    PubMed

    Wang, Yuechun; Reis, Cesar; Applegate, Richard; Stier, Gary; Martin, Robert; Zhang, John H

    2015-10-01

    In the area of brain injury and neurodegenerative diseases, a plethora of experimental and clinical evidence strongly indicates the promise of therapeutically exploiting the endogenous adaptive system at various levels like triggers, mediators and the end-effectors to stimulate and mobilize intrinsic protective capacities against brain injuries. It is believed that ischemic pre-conditioning and post-conditioning are actually the strongest known interventions to stimulate the innate neuroprotective mechanism to prevent or reverse neurodegenerative diseases including stroke and traumatic brain injury. Recently, studies showed the effectiveness of ischemic per-conditioning in some organs. Therefore the term ischemic conditioning, including all interventions applied pre-, per- and post-ischemia, which spans therapeutic windows in 3 time periods, has recently been broadly accepted by scientific communities. In addition, it is extensively acknowledged that ischemia-mediated protection not only affects the neurons but also all the components of the neurovascular network (consisting of neurons, glial cells, vascular endothelial cells, pericytes, smooth muscle cells, and venule/veins). The concept of cerebroprotection has been widely used in place of neuroprotection. Intensive studies on the cellular signaling pathways involved in ischemic conditioning have improved the mechanistic understanding of tolerance to cerebral ischemia. This has added impetus to exploration for potential pharmacologic mimetics, which could possibly induce and maximize inherent protective capacities. However, most of these studies were performed in rodents, and the efficacy of these mimetics remains to be evaluated in human patients. Several classical signaling pathways involving apoptosis, inflammation, or oxidation have been elaborated in the past decades. Newly characterized mechanisms are emerging with the advances in biotechnology and conceptual renewal. In this review we are going to focus on those recently reported methodological and mechanistic discoveries in the realm of ischemic conditioning. Due to the varied time differences of ischemic conditioning in different animal models and clinical trials, it is important to define optimal timing to achieve the best conditioning induced neuroprotection. This brings not only an opportunity in the treatment of stroke, but challenges as well, as data is just becoming available and the procedures are not yet optimized. The purpose of this review is to shed light on exploiting these ischemic conditioning modalities to protect the cerebrovascular system against diverse injuries and neurodegenerative disorders. PMID:25900056

  4. Running TCP/IP over ATM Networks.

    ERIC Educational Resources Information Center

    Witt, Michael

    1995-01-01

    Discusses Internet protocol (IP) and subnets and describes how IP may operate over asynchronous transfer mode (ATM). Topics include TCP (transmission control protocol), ATM cells and adaptation layers, a basic architectural model for IP over ATM, address resolution, mapping IP to a subnet technology, and connection management strategy. (LRW)

  5. Fetal asphyctic preconditioning alters the transcriptional response to perinatal asphyxia

    PubMed Central

    2014-01-01

    Background Genomic reprogramming is thought to be, at least in part, responsible for the protective effect of brain preconditioning. Unraveling mechanisms of this endogenous neuroprotection, activated by preconditioning, is an important step towards new clinical strategies for treating asphyctic neonates. Therefore, we investigated whole-genome transcriptional changes in the brain of rats which underwent perinatal asphyxia (PA), and rats where PA was preceded by fetal asphyctic preconditioning (FAPA). Offspring were sacrificed 6 h and 96 h after birth, and whole-genome transcription was investigated using the Affymetrix Gene1.0ST chip. Microarray data were analyzed with the Bioconductor Limma package. In addition to univariate analysis, we performed Gene Set Enrichment Analysis (GSEA) in order to derive results with maximum biological relevance. Results We observed minimal, 25% or less, overlap of differentially regulated transcripts across different experimental groups which leads us to conclude that the transcriptional phenotype of these groups is largely unique. In both the PA and FAPA group we observe an upregulation of transcripts involved in cellular stress. Contrastingly, transcripts with a function in the cell nucleus were mostly downregulated in PA animals, while we see considerable upregulation in the FAPA group. Furthermore, we observed that histone deacetylases (HDACs) are exclusively regulated in FAPA animals. Conclusions This study is the first to investigate whole-genome transcription in the neonatal brain after PA alone, and after perinatal asphyxia preceded by preconditioning (FAPA). We describe several genes/pathways, such as ubiquitination and proteolysis, which were not previously linked to preconditioning-induced neuroprotection. Furthermore, we observed that the majority of upregulated genes in preconditioned animals have a function in the cell nucleus, including several epigenetic players such as HDACs, which suggests that epigenetic mechanisms are likely to play a role in preconditioning-induced neuroprotection. PMID:24885038

  6. Hyperbaric oxygen preconditioning attenuates hyperglycemia-enhanced hemorrhagic transformation by inhibiting matrix metalloproteinases in focal cerebral ischemia in rats.

    PubMed

    Soejima, Yoshiteru; Hu, Qin; Krafft, Paul R; Fujii, Mutsumi; Tang, Jiping; Zhang, John H

    2013-09-01

    Hyperglycemia dramatically aggravates brain infarct and hemorrhagic transformation (HT) after ischemic stroke. Oxidative stress and matrix metalloproteinases (MMPs) play an important role in the pathophysiology of HT. Hyperbaric oxygen preconditioning (HBO-PC) has been proved to decrease oxidative stress and has been demonstrated to be neuroprotective in experimental stroke models. The present study determined whether HBO-PC would ameliorate HT by a pre-ischemic increase of reactive oxygen species (ROS) generation, and a suppression of MMP-2 and MMP-9 in hyperglycemic middle cerebral artery occlusion (MCAO) rats. Rats were pretreated with HBO (100% O?, 2.5 atmosphere absolutes) 1 h daily for 5 days before MCAO. Acute hyperglycemia was induced by an injection of 50% dextrose. Neurological deficits, infarction volume and hemorrhagic volume were assessed 24 h and 7 days after ischemia. ROS scavenger n-acetyl cysteine (NAC), hypoxia-inducible factor-1? (HIF-1?), inhibitor 2-methoxyestradiol (2ME2) and activator cobalt chloride (CoCl?), and MMP inhibitor SB-3CT were administrated for mechanism study. The activity of MMP-2 and MMP-9, and the expression HIF-1? were measured. HBO-PC improved neurological deficits, and reduced hemorrhagic volume; the expression of HIF-1? was significantly decreased, and the activity of MMP-2 and MMP-9 was reduced by HBO-PC compared with vehicle group. Our results suggested that HBO-PC attenuated HT via decreasing HIF-1? and its downstream MMP-2 and MMP-9 in hyperglycemic MCAO rats. PMID:23537951

  7. Interaction of risk factors, comorbidities, and comedications with ischemia/reperfusion injury and cardioprotection by preconditioning, postconditioning, and remote conditioning.

    PubMed

    Ferdinandy, Péter; Hausenloy, Derek J; Heusch, Gerd; Baxter, Gary F; Schulz, Rainer

    2014-10-01

    Pre-, post-, and remote conditioning of the myocardium are well described adaptive responses that markedly enhance the ability of the heart to withstand a prolonged ischemia/reperfusion insult and provide therapeutic paradigms for cardioprotection. Nevertheless, more than 25 years after the discovery of ischemic preconditioning, we still do not have established cardioprotective drugs on the market. Most experimental studies on cardioprotection are still undertaken in animal models, in which ischemia/reperfusion is imposed in the absence of cardiovascular risk factors. However, ischemic heart disease in humans is a complex disorder caused by, or associated with, cardiovascular risk factors and comorbidities, including hypertension, hyperlipidemia, diabetes, insulin resistance, heart failure, altered coronary circulation, and aging. These risk factors induce fundamental alterations in cellular signaling cascades that affect the development of ischemia/reperfusion injury per se and responses to cardioprotective interventions. Moreover, some of the medications used to treat these risk factors, including statins, nitrates, and antidiabetic drugs, may impact cardioprotection by modifying cellular signaling. The aim of this article is to review the recent evidence that cardiovascular risk factors and their medication may modify the response to cardioprotective interventions. We emphasize the critical need to take into account the presence of cardiovascular risk factors and concomitant medications when designing preclinical studies for the identification and validation of cardioprotective drug targets and clinical studies. This will hopefully maximize the success rate of developing rational approaches to effective cardioprotective therapies for the majority of patients with multiple risk factors. PMID:25261534

  8. Transplantation of hypoxia preconditioned bone marrow mesenchymal stem cells enhances angiogenesis and neurogenesis after cerebral ischemia in rats

    E-print Network

    Hayar, Abdallah

    Transplantation of hypoxia preconditioned bone marrow mesenchymal stem cells enhances angiogenesis online 9 March 2012 Keywords: Hypoxic preconditioning Bone marrow mesenchymal stem cell Transplantation that hypoxic preconditioning of bone marrow mesenchymal stem cells (BMSCs) could not only enhance

  9. Nanoparticle Pre-Conditioning for Enhanced Thermal Therapies in Cancer

    PubMed Central

    Shenoi, Mithun M.; Shah, Neha B.; Griffin, Robert J.; Vercellotti, Gregory M.; Bischof, John C.

    2011-01-01

    Nanoparticles show tremendous promise in the safe and effective delivery of molecular adjuvants to enhance local cancer therapy. One important form of local cancer treatment that suffers from local recurrence and distant metastases is thermal therapy. Here we review a new concept involving the use of nanoparticle delivered adjuvants to “pre-condition” or alter the vascular and immunological biology of the tumor to enhance its susceptibility to thermal therapy. To this end, a number of opportunities to combine nanoparticles with vascular and immunologically active agents are reviewed. One specific example of pre-conditioning involves a gold nanoparticle tagged with a vascular targeting agent (i.e. TNF-?). This nanoparticle embodiment demonstrates pre-conditioning through a dramatic reduction in tumor blood flow and induction of vascular damage which recruits a strong and sustained inflammatory infiltrate in the tumor. The ability of this nanoparticle pre-conditioning to enhance subsequent heat or cold thermal therapy in a variety of tumor models is reviewed. Finally, the potential for future clinical imaging to judge the extent of pre-conditioning and thus the optimal timing and extent of combinatorial thermal therapy is discussed. PMID:21542691

  10. Implementation of Preconditioned Dual-Time Procedures in OVERFLOW

    NASA Technical Reports Server (NTRS)

    Pandya, Shishir A.; Venkateswaran, Sankaran; Pulliam, Thomas H.; Kwak, Dochan (Technical Monitor)

    2003-01-01

    Preconditioning methods have become the method of choice for the solution of flowfields involving the simultaneous presence of low Mach and transonic regions. It is well known that these methods are important for insuring accurate numerical discretization as well as convergence efficiency over various operating conditions such as low Mach number, low Reynolds number and high Strouhal numbers. For unsteady problems, the preconditioning is introduced within a dual-time framework wherein the physical time-derivatives are used to march the unsteady equations and the preconditioned time-derivatives are used for purposes of numerical discretization and iterative solution. In this paper, we describe the implementation of the preconditioned dual-time methodology in the OVERFLOW code. To demonstrate the performance of the method, we employ both simple and practical unsteady flowfields, including vortex propagation in a low Mach number flow, flowfield of an impulsively started plate (Stokes' first problem) arid a cylindrical jet in a low Mach number crossflow with ground effect. All the results demonstrate that the preconditioning algorithm is responsible for improvements to both numerical accuracy and convergence efficiency and, thereby, enables low Mach number unsteady computations to be performed at a fraction of the cost of traditional time-marching methods.

  11. Operator-Based Preconditioning of Stiff Hyperbolic Systems

    SciTech Connect

    Reynolds, Daniel R.; Samtaney, Ravi; Woodward, Carol S.

    2009-02-09

    We introduce an operator-based scheme for preconditioning stiff components encoun- tered in implicit methods for hyperbolic systems of partial differential equations posed on regular grids. The method is based on a directional splitting of the implicit operator, followed by a char- acteristic decomposition of the resulting directional parts. This approach allows for solution to any number of characteristic components, from the entire system to only the fastest, stiffness-inducing waves. We apply the preconditioning method to stiff hyperbolic systems arising in magnetohydro- dynamics and gas dynamics. We then present numerical results showing that this preconditioning scheme works well on problems where the underlying stiffness results from the interaction of fast transient waves with slowly-evolving dynamics, scales well to large problem sizes and numbers of processors, and allows for additional customization based on the specific problems under study.

  12. Liquid hydrogen turbopump rapid start program. [thermal preconditioning using coatings

    NASA Technical Reports Server (NTRS)

    Wong, G. S.

    1973-01-01

    This program was to analyze, test, and evaluate methods of achieving rapid-start of a liquid hydrogen feed system (inlet duct and turbopump) using a minimum of thermal preconditioning time and propellant. The program was divided into four tasks. Task 1 includes analytical studies of the testing conducted in the other three tasks. Task 2 describes the results from laboratory testing of coating samples and the successful adherence of a KX-635 coating to the internal surfaces of the feed system tested in Task 4. Task 3 presents results of testing an uncoated feed system. Tank pressure was varied to determine the effect of flowrate on preconditioning. The discharge volume and the discharge pressure which initiates opening of the discharge valve were varied to determine the effect on deadhead (no through-flow) start transients. Task 4 describes results of testing a similar, internally coated feed system and illustrates the savings in preconditioning time and propellant resulting from the coatings.

  13. On adaptive weighted polynomial preconditioning for Hermitian positive definite matrices

    NASA Technical Reports Server (NTRS)

    Fischer, Bernd; Freund, Roland W.

    1992-01-01

    The conjugate gradient algorithm for solving Hermitian positive definite linear systems is usually combined with preconditioning in order to speed up convergence. In recent years, there has been a revival of polynomial preconditioning, motivated by the attractive features of the method on modern architectures. Standard techniques for choosing the preconditioning polynomial are based only on bounds for the extreme eigenvalues. Here a different approach is proposed, which aims at adapting the preconditioner to the eigenvalue distribution of the coefficient matrix. The technique is based on the observation that good estimates for the eigenvalue distribution can be derived after only a few steps of the Lanczos process. This information is then used to construct a weight function for a suitable Chebyshev approximation problem. The solution of this problem yields the polynomial preconditioner. In particular, we investigate the use of Bernstein-Szego weights.

  14. 40 CFR 85.2219 - Idle test with loaded preconditioning-EPA 91.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 2013-07-01 2013-07-01 false Idle test with loaded preconditioning-EPA 91. 85.2219...Emission Control System Performance Warranty Short Tests § 85.2219 Idle test with loaded preconditioning—EPA 91. (a)...

  15. 40 CFR 92.125 - Pre-test procedures and preconditioning.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Pre-test procedures and preconditioning. 92.125 Section...POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Test Procedures § 92.125 Pre-test procedures and preconditioning. (a)...

  16. 40 CFR 85.2218 - Preconditioned idle test-EPA 91.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 2012-07-01 false Preconditioned idle test-EPA 91. 85.2218 Section 85.2218 ...Emission Control System Performance Warranty Short Tests § 85.2218 Preconditioned idle test—EPA 91. (a) General requirements...

  17. 40 CFR 86.153-98 - Vehicle and canister preconditioning; refueling test.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...and canister preconditioning; refueling test. 86.153-98 Section 86.153-98...Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.153-98 Vehicle and canister preconditioning; refueling test. (a) Vehicle and canister...

  18. 40 CFR 85.2219 - Idle test with loaded preconditioning-EPA 91.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 2011-07-01 2011-07-01 false Idle test with loaded preconditioning-EPA 91. 85.2219...Emission Control System Performance Warranty Short Tests § 85.2219 Idle test with loaded preconditioning—EPA 91. (a)...

  19. 40 CFR 86.153-98 - Vehicle and canister preconditioning; refueling test.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...and canister preconditioning; refueling test. 86.153-98 Section 86.153-98...Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.153-98 Vehicle and canister preconditioning; refueling test. (a) Vehicle and canister...

  20. 40 CFR 85.2219 - Idle test with loaded preconditioning-EPA 91.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 2010-07-01 2010-07-01 false Idle test with loaded preconditioning-EPA 91. 85.2219...Emission Control System Performance Warranty Short Tests § 85.2219 Idle test with loaded preconditioning—EPA 91. (a)...

  1. 40 CFR 85.2218 - Preconditioned idle test-EPA 91.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 2011-07-01 false Preconditioned idle test-EPA 91. 85.2218 Section 85.2218 ...Emission Control System Performance Warranty Short Tests § 85.2218 Preconditioned idle test—EPA 91. (a) General requirements...

  2. 40 CFR 86.153-98 - Vehicle and canister preconditioning; refueling test.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...and canister preconditioning; refueling test. 86.153-98 Section 86.153-98...Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.153-98 Vehicle and canister preconditioning; refueling test. (a) Vehicle and canister...

  3. 40 CFR 85.2219 - Idle test with loaded preconditioning-EPA 91.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 2012-07-01 2012-07-01 false Idle test with loaded preconditioning-EPA 91. 85.2219...Emission Control System Performance Warranty Short Tests § 85.2219 Idle test with loaded preconditioning—EPA 91. (a)...

  4. 40 CFR 86.153-98 - Vehicle and canister preconditioning; refueling test.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...and canister preconditioning; refueling test. 86.153-98 Section 86.153-98...Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.153-98 Vehicle and canister preconditioning; refueling test. (a) Vehicle and canister...

  5. 40 CFR 85.2218 - Preconditioned idle test-EPA 91.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 2010-07-01 false Preconditioned idle test-EPA 91. 85.2218 Section 85.2218 ...Emission Control System Performance Warranty Short Tests § 85.2218 Preconditioned idle test—EPA 91. (a) General requirements...

  6. 40 CFR 86.153-98 - Vehicle and canister preconditioning; refueling test.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...and canister preconditioning; refueling test. 86.153-98 Section 86.153-98...Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.153-98 Vehicle and canister preconditioning; refueling test. (a) Vehicle and canister...

  7. 40 CFR 85.2218 - Preconditioned idle test-EPA 91.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 2013-07-01 false Preconditioned idle test-EPA 91. 85.2218 Section 85.2218 ...Emission Control System Performance Warranty Short Tests § 85.2218 Preconditioned idle test—EPA 91. (a) General requirements...

  8. Scalable Preconditioned Eigenvalue Solver in Hypre Merico Argentati and Andrew Knyazev (speaker)

    E-print Network

    Knyazev, Andrew

    Scalable Preconditioned Eigenvalue Solver in Hypre Merico Argentati and Andrew Knyazev (speaker of a symmetric matrix using preconditioning directly, without using the shift-and-invert scheme and inner

  9. 40 CFR 1065.590 - PM sampling media (e.g., filters) preconditioning and tare weighing.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... false PM sampling media (e.g., filters) preconditioning and tare weighing...590 PM sampling media (e.g., filters) preconditioning and tare weighing...to prepare PM sampling media (e.g., filters) and equipment for PM...

  10. Fourier analysis of finite element preconditioned collocation schemes

    NASA Technical Reports Server (NTRS)

    Deville, Michel O.; Mund, Ernest H.

    1990-01-01

    The spectrum of the iteration operator of some finite element preconditioned Fourier collocation schemes is investigated. The first part of the paper analyses one-dimensional elliptic and hyperbolic model problems and the advection-diffusion equation. Analytical expressions of the eigenvalues are obtained with use of symbolic computation. The second part of the paper considers the set of one-dimensional differential equations resulting from Fourier analysis (in the tranverse direction) of the 2-D Stokes problem. All results agree with previous conclusions on the numerical efficiency of finite element preconditioning schemes.

  11. A subspace preconditioning algorithm for eigenvector/eigenvalue computation

    SciTech Connect

    Bramble, J.H.; Knyazev, A.V.; Pasciak, J.E.

    1996-12-31

    We consider the problem of computing a modest number of the smallest eigenvalues along with orthogonal bases for the corresponding eigen-spaces of a symmetric positive definite matrix. In our applications, the dimension of a matrix is large and the cost of its inverting is prohibitive. In this paper, we shall develop an effective parallelizable technique for computing these eigenvalues and eigenvectors utilizing subspace iteration and preconditioning. Estimates will be provided which show that the preconditioned method converges linearly and uniformly in the matrix dimension when used with a uniform preconditioner under the assumption that the approximating subspace is close enough to the span of desired eigenvectors.

  12. Thermal Preconditioning and Heat-Shock Protein 72 Preserve Synaptic Transmission during Thermal Stress

    E-print Network

    Robertson, Meldrum

    Thermal Preconditioning and Heat-Shock Protein 72 Preserve Synaptic Transmission during Thermal, exposing the mammalian CNS to nonle- thal heat stress (i.e., thermal preconditioning) increases levels that generates respiratory rhythm (the pre- Bo¨ tzinger complex), we show that thermal preconditioning has

  13. 40 CFR 86.153-98 - Vehicle and canister preconditioning; refueling test.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Vehicle and canister preconditioning... New Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.153-98 Vehicle and canister preconditioning; refueling test. (a) Vehicle and canister preconditioning. Vehicles and vapor storage...

  14. 40 CFR 86.153-98 - Vehicle and canister preconditioning; refueling test.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Vehicle and canister preconditioning... New Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.153-98 Vehicle and canister preconditioning; refueling test. (a) Vehicle and canister preconditioning. Vehicles and vapor storage...

  15. 40 CFR 86.153-98 - Vehicle and canister preconditioning; refueling test.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 19 2012-07-01 2012-07-01 false Vehicle and canister preconditioning... New Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.153-98 Vehicle and canister preconditioning; refueling test. (a) Vehicle and canister preconditioning. Vehicles and vapor storage...

  16. Continuously Connected With Mobile IP

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Cisco Systems developed Cisco Mobile Networks, making IP devices mobile. With this innovation, a Cisco router and its connected IP devices can roam across network boundaries and connection types. Because a mobile user is able to keep the same IP address while roaming, a live IP connection can be maintained without interruption. Glenn Research Center jointly tested the technology with Cisco, and is working to use it on low-earth-orbiting research craft. With Cisco's Mobile Networks functionality now available in Cisco IOS Software release 12.2(4)T, the commercial advantages and benefits are numerous. The technology can be applied to public safety, military/homeland security, emergency management services, railroad and shipping systems, and the automotive industry. It will allow ambulances, police, firemen, and the U.S. Coast Guard to stay connected to their networks while on the move. In the wireless battlefield, the technology will provide rapid infrastructure deployment for U.S. national defense. Airline, train, and cruise passengers utilizing Cisco Mobile Networks can fly all around the world with a continuous Internet connection. Cisco IOS(R) Software is a registered trademark of Cisco Systems.

  17. Advanced Networking Voice over IP

    E-print Network

    Lo Cigno, Renato Antonio

    by the original monopoly system The structure was tailored and optimized for voice transport Local ExchangeIP: Intro/H.323 11 "A" Compression Law ( ) ( ) ( ) ( ) + + + = AX A X X A A Y ln1 ln1 sgn ln1 law A -1

  18. Erythropoietin: Powerful Protection of Ischemic and Post-Ischemic Brain

    PubMed Central

    Nguyen, Anh Q.; Cherry, Brandon H.; Scott, Gary F.; Ryou, Myoung-Gwi; Mallet, Robert T.

    2015-01-01

    Ischemic brain injury inflicted by stroke and cardiac arrest ranks among the leading causes of death and long-term disability in the United States. The brain consumes large amounts of metabolic substrates and oxygen to sustain its energy requirements. Consequently, the brain is exquisitely sensitive to interruptions in its blood supply, and suffers irreversible damage after 10–15 minutes of severe ischemia. Effective treatments to protect the brain from stroke and cardiac arrest have proven elusive, due to the complexities of the injury cascades ignited by ischemia and reperfusion. Although recombinant tissue plasminogen activator and therapeutic hypothermia have proven efficacious for stroke and cardiac arrest, respectively, these treatments are constrained by narrow therapeutic windows, potentially detrimental side effects and the limited availability of hypothermia equipment. Mounting evidence demonstrates the cytokine hormone erythropoietin (EPO) to be a powerful neuroprotective agent and a potential adjuvant to established therapies. Classically, EPO originating primarily in the kidneys promotes erythrocyte production by suppressing apoptosis of proerythroid progenitors in bone marrow. However, the brain is capable of producing EPO, and EPO’s membrane receptors and signaling components also are expressed in neurons and astrocytes. EPO activates signaling cascades that increase the brain’s resistance to ischemia-reperfusion stress by stabilizing mitochondrial membranes, limiting formation of reactive oxygen and nitrogen intermediates, and suppressing pro-inflammatory cytokine production and neutrophil infiltration. Collectively, these mechanisms preserve functional brain tissue and, thus, improve neurocognitive recovery from brain ischemia. This article reviews the mechanisms mediating EPO-induced brain protection, critiques the clinical utility of exogenous EPO to preserve brain threatened by ischemic stroke and cardiac arrest, and discusses the prospects for induction of EPO production within the brain by the intermediary metabolite, pyruvate. PMID:24595981

  19. Characteristics of Misclassified CT Perfusion Ischemic Core in Patients with Acute Ischemic Stroke

    PubMed Central

    Geuskens, Ralph R. E. G.; Borst, Jordi; Lucas, Marit; Boers, A. M. Merel; Berkhemer, Olvert A.; Roos, Yvo B. W. E. M.; van Walderveen, Marianne A. A.; Jenniskens, Sjoerd F. M.; van Zwam, Wim H.; Dippel, Diederik W. J.; Majoie, Charles B. L. M.; Marquering, Henk A.

    2015-01-01

    Background CT perfusion (CTP) is used to estimate the extent of ischemic core and penumbra in patients with acute ischemic stroke. CTP reliability, however, is limited. This study aims to identify regions misclassified as ischemic core on CTP, using infarct on follow-up noncontrast CT. We aim to assess differences in volumetric and perfusion characteristics in these regions compared to areas that ended up as infarct on follow-up. Materials and Methods This study included 35 patients with >100 mm brain coverage CTP. CTP processing was performed using Philips software (IntelliSpace 7.0). Final infarct was automatically segmented on follow-up noncontrast CT and used as reference. CTP and follow-up noncontrast CT image data were registered. This allowed classification of ischemic lesion agreement (core on CTP: rMTT?145%, aCBV<2.0 ml/100g and infarct on follow-up noncontrast CT) and misclassified ischemic core (core on CTP, not identified on follow-up noncontrast CT) regions. False discovery ratio (FDR), defined as misclassified ischemic core volume divided by total CTP ischemic core volume, was calculated. Absolute and relative CTP parameters (CBV, CBF, and MTT) were calculated for both misclassified CTP ischemic core and ischemic lesion agreement regions and compared using paired rank-sum tests. Results Median total CTP ischemic core volume was 49.7ml (IQR:29.9ml-132ml); median misclassified ischemic core volume was 30.4ml (IQR:20.9ml-77.0ml). Median FDR between patients was 62% (IQR:49%-80%). Median relative mean transit time was 243% (IQR:198%-289%) and 342% (IQR:249%-432%) for misclassified and ischemic lesion agreement regions, respectively. Median absolute cerebral blood volume was 1.59 (IQR:1.43–1.79) ml/100g (P<0.01) and 1.38 (IQR:1.15–1.49) ml/100g (P<0.01) for misclassified ischemic core and ischemic lesion agreement, respectively. All CTP parameter values differed significantly. Conclusion For all patients a considerable region of the CTP ischemic core is misclassified. CTP parameters significantly differed between ischemic lesion agreement and misclassified CTP ischemic core, suggesting that CTP analysis may benefit from revisions. PMID:26536226

  20. Finding Chemical Reaction Paths with a Multilevel Preconditioning Seyit Kale,,

    E-print Network

    Dinner, Aaron

    Finding Chemical Reaction Paths with a Multilevel Preconditioning Protocol Seyit Kale,, Olaseni for chemical reactions can be computationally costly owing to the level of quantum- chemical theory needed for the reaction path iteratively. These methods have yielded important insights in quantum chemical contexts9

  1. 33 CFR 183.220 - Preconditioning for tests.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of More Than 2 Horsepower General § 183.220 Preconditioning for tests. A boat must meet the... boat. (b) The boat must be loaded with a quantity of weight that, when submerged, is equal to the...

  2. 40 CFR 1065.516 - Sample system decontamination and preconditioning.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Sample system decontamination and preconditioning. 1065.516 Section 1065.516 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Performing an Emission Test Over Specified Duty Cycles § 1065.516 Sample...

  3. Effect of Hypoxic Preconditioning on Stress Reaction in Rats.

    PubMed

    Naryzhnaya, N V; Maslov, L N; Vychuzhanova, E A; Sementsov, A S; Podoksyonov, Yu K; Portnichenko, A G; Lishmanov, Yu B

    2015-08-01

    In rats, immobilization stress (24 h) induced involution of the thymus and spleen, adrenal hypertrophy, and pronounced elevation (by 67%) of serum cortisol in comparison with intact animals; the mean number of stomach ulcers in rats subjected to stress was 6.9. Hypoxic preconditioning consisting of 6 sessions of 10-min hypoxia (8% O2) followed by 10-min reoxygenation with atmospheric air induced adrenal hypertrophy and spleen involution, but did not change blood cortisol level; no stomach ulcers were found in preconditioned rats. In rats subjected to both hypoxic preconditioning and immobilization, the weights of the thymus, adrenal glands, and spleen, as well as cortisol level did not differ from the corresponding parameters in rats subjected to immobilization stress alone. The number of stomach ulcers in experimental rats was 1.5-fold lower than in the stress-control ones. Thus, hypoxic preconditioning exerts a pronounced preventive anti-ulcer effect during immobilization, but it does not affect other indices of the stress reaction. PMID:26385407

  4. Behavioral/Systems/Cognitive Octopamine Mediates Thermal Preconditioning of the

    E-print Network

    Robertson, Meldrum

    with a high (45°C) and prolonged (3 h) exposure to heat followed by a 1 h recovery [heat shock treatment (HS generation. However, OA treatment by bath applications (10 4 M OA) or by injections into the hemocoel (2 g/10 l OA) mimicked heat shock preconditioning and improved the thermotolerance of the motor pattern

  5. 40 CFR 86.132-00 - Vehicle preconditioning.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...highway, US06 or SC03 test cycles. (ii) [Reserved] (iii) If a manufacturer has concerns about fuel effects on adaptive memory systems, a manufacturer may precondition a test vehicle on test fuel and the US06 cycle. Upon request from a...

  6. PRECONDITIONED ITERATIVE METHODS FOR SOLVING LINEAR LEAST SQUARES PROBLEMS

    E-print Network

    Tùma, Miroslav

    ´IN, JOS´E MAS AND MIROSLAV T°UMA Abstract. New preconditioning strategies for solving m × n overdetermined´arenskou vez´i 2, 182 07 Prague 8, Czech Republic, (tuma@cs.cas.cz). 1 #12;equations and a factorization

  7. 40 CFR 86.132-00 - Vehicle preconditioning.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 19 2013-07-01 2013-07-01 false Vehicle preconditioning. 86.132-00 Section 86.132-00 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1977 and Later Model Year New...

  8. 40 CFR 86.132-00 - Vehicle preconditioning.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Emission Regulations for 1977 and Later Model Year New Light-Duty Vehicles and New Light-Duty Trucks and New Otto-Cycle Complete Heavy-Duty...subsequent test shall begin with the preconditioning drive specified in § 86.132-96(c)(1). The...

  9. On preconditioning strategies for geotechnics C.E. Augarde

    E-print Network

    Augarde, Charles

    On preconditioning strategies for geotechnics C.E. Augarde School of Engineering, University in geotechnics is overwhelmingly dominated by the use of finite element (FE) methods. They have proved" to model the majority of geotechnical problems, although this was a decision based on the capabilities

  10. Preconditioned Multigrid Simulation of an Axisymmetric Laminar Diffusion Flame \\Lambda

    E-print Network

    Zhang, Jun

    the growth of the Krylov iterations. Key words ­ laminar diffusion flame, vorticity­velocity formulationPreconditioned Multigrid Simulation of an Axisymmetric Laminar Diffusion Flame \\Lambda Samir Karaa of an elliptic flame sheet problem. By selecting the generalized minimum residual method as the linear smoother

  11. PRECONDITIONING BY APPROXIMATE SCHUR COMPLEMENTS ON HIERARCHICAL GRIDS

    E-print Network

    PRECONDITIONING BY APPROXIMATE SCHUR COMPLEMENTS ON HIERARCHICAL GRIDS C. BRAND AND J. KRAUS], [8] and [5]. A specific ordering of the unknowns, introduced by Brand [4], improved the asymptotic and Eijkhout investigated in their work [1] also W­cycles realized by employment of second order matrix

  12. Numerical simulation of cavitating flows based on preconditioning technique

    NASA Astrophysics Data System (ADS)

    Goncalvès, E.

    2013-10-01

    A preconditioned numerical method for gas-liquid two-phase flows is applied to solve cavitating flow. The mass transfer between phases is modelled through a void ratio transport equation. Two-dimensional turbulent Venturi flows are computed. Comparisons with a 3-equation model and experimental data are provided and discussed.

  13. 40 CFR 86.132-00 - Vehicle preconditioning.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Vehicle preconditioning. 86.132-00 Section 86.132-00 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1977 and Later Model Year New...

  14. Universitat Regensburg Preconditioning for Allen-Cahn variational

    E-print Network

    Blank, Luise - Naturwissenschaftliche Fakultät I

    -local constraints Luise Blank, Lavinia Sarbu and Martin Stoll Preprint Nr. 11/2010 #12;PRECONDITIONING FOR ALLEN-CAHN VARIATIONAL INEQUALITIES WITH NON-LOCAL CONSTRAINTS LUISE BLANK§, LAVINIA SARBUAND MARTIN STOLL Abstract. AMS subject classifications. Primary 65F10, 65N22, 65F50 Secondary 76D07 Key words. PDE

  15. 40 CFR 86.232-94 - Vehicle preconditioning.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.232-94 ...fuel fill. The test fuel shall be at a temperature less than or equal to 60 °F. For...certification testing, precondition vehicles at temperatures above 20 °F (?7 °C) and with...

  16. 40 CFR 86.232-94 - Vehicle preconditioning.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.232-94 ...fuel fill. The test fuel shall be at a temperature less than or equal to 60 °F. For...certification testing, precondition vehicles at temperatures above 20 °F (?7 °C) and with...

  17. 40 CFR 86.232-94 - Vehicle preconditioning.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.232-94 ...fuel fill. The test fuel shall be at a temperature less than or equal to 60 °F. For...certification testing, precondition vehicles at temperatures above 20 °F (?7 °C) and with...

  18. 40 CFR 86.232-94 - Vehicle preconditioning.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.232-94 ...fuel fill. The test fuel shall be at a temperature less than or equal to 60 °F. For...certification testing, precondition vehicles at temperatures above 20 °F (?7 °C) and with...

  19. AN INVERSE FREE PRECONDITIONED KRYLOV SUBSPACE METHOD FOR

    E-print Network

    Kentucky, University of

    AN INVERSE FREE PRECONDITIONED KRYLOV SUBSPACE METHOD FOR SYMMETRIC GENERALIZED EIGENVALUE PROBLEMS Gene H. Golub #3; Qiang Ye y ABSTRACT In this paper, we present an inverse free Krylov subspace method, Stanford University, Stanford, CA 94305. E-mail : golub@sccm.stanford.edu. Research supported in part

  20. VoIP in a Campus Environment

    ERIC Educational Resources Information Center

    Young, Dan

    2005-01-01

    Internet Protocol (IP) Telephony, or voice-over IP (VoIP), has proved to be a wise decision for many organizations. This technology crosses the boundaries of public and private networks, enterprise and residential markets, voice and data technologies, as well as local and long-distance services. The convergence of voice and data into a single,…

  1. CISCO IP 7941-7961 FONCTIONS TLPHONIQUES

    E-print Network

    Charette, André

    CISCO IP 7941-7961 FONCTIONS TÉLÉPHONIQUES FONCTIONS DE BASE BOUTON DE LIGNE (DESCRIPTION DES raccrocher pour effectuer le transfert de l'appel. Cisco_IP_7941_7961_Fr_CUCM_V7.0_20090320[1].doc 1 de 7 #12;CISCO IP 7941-7961 FONCTIONS TÉLÉPHONIQUES APPEL CONFÉRENCE Vous pouvez établir un appel conférence

  2. Cisco IP 7935/7936 FONCTIONS TLPHONIQUES

    E-print Network

    Charette, André

    Cisco IP 7935/7936 FONCTIONS TÉLÉPHONIQUES Légende des touches de fonctions 1 Modèle de l surbrillance dans le menu. 6 Touches interactives Permet de sélectionner les touches interactives. #12;Cisco IP la sonnerie et le contraste. #12;Cisco IP 7935/7936 FONCTIONS TÉLÉPHONIQUES Légende des touches

  3. CISCO IP 7905-7912 FONCTIONS TLPHONIQUES

    E-print Network

    Charette, André

    CISCO IP 7905-7912 FONCTIONS TÉLÉPHONIQUES FONCTIONS DE BASE FAIRE UN APPEL · Soulever le combiné numéros erronés. Cisco_IP_7905_7912_Fr_CUCM_V7.0_20090320[1].doc 1 de 6 #12;CISCO IP 7905-7912 FONCTIONS

  4. CISCO IP 7940-7960 FONCTIONS TLPHONIQUES

    E-print Network

    Charette, André

    CISCO IP 7940-7960 FONCTIONS TÉLÉPHONIQUES FONCTIONS DE BASE FAIRE UN APPEL · Soulever le combiné navigation; · appuyer sur la touche Joindre (tous les intervenants seront en communication). Cisco_IP_7940_7960_Fr_CUCM_V7.0_20090320[1].doc 1 de 7 #12;CISCO IP 7940-7960 FONCTIONS TÉLÉPHONIQUES APPEL CONFÉRENCE

  5. CISCO IP 7906/7911 FONCTIONS TLPHONIQUES

    E-print Network

    Charette, André

    CISCO IP 7906/7911 FONCTIONS TÉLÉPHONIQUES FONCTIONS DE BASE FAIRE UN APPEL · Soulever le combiné sur la touche Cisco_IP_7906_7911_Fr_CUCM_V7.0_20090320[1].doc 1 de 6 #12;CISCO IP 7906/7911 FONCTIONS TÉLÉPHONIQUES CONFÉRENCE LISTE Lorsque vous êtes en appel

  6. A UML-Based Approach for Heterogeneous IP Integration Abstract -With increasing availability of predefined IP

    E-print Network

    Wong, Weng Fai

    proposed. Among these, the Open Core Protocol (OCP) by OCP-IP [13] has gained wide industrial acceptance. Today, many IPs are OCP-compliant. However, for existing non OCP compliant IP cores, it is expensiveA UML-Based Approach for Heterogeneous IP Integration Abstract - With increasing availability

  7. Endovascular Therapy for Ischemic Stroke

    PubMed Central

    Appireddy, Ramana M R; Demchuk, Andrew M; Goyal, Mayank; Menon, Bijoy K; Eesa, Muneer; Choi, Philip

    2015-01-01

    The utility of intravenous tissue plasminogen activator (IV t-PA) in improving the clinical outcomes after acute ischemic stroke has been well demonstrated in past clinical trials. Though multiple initial small series of endovascular stroke therapy had shown good outcomes as compared to IV t-PA, a similar beneficial effect had not been translated in multiple randomized clinical trials of endovascular stroke therapy. Over the same time, there have been parallel advances in imaging technology and better understanding and utility of the imaging in therapy of acute stroke. In this review, we will discuss the evolution of endovascular stroke therapy followed by a discussion of the key factors that have to be considered during endovascular stroke therapy and directions for future endovascular stroke trials. PMID:25628731

  8. In-Hospital Ischemic Stroke

    PubMed Central

    2015-01-01

    Between 2.2% and 17% of all strokes have symptom onset during hospitalization in a patient originally admitted for another diagnosis or procedure. These in-hospital strokes represent a unique population with different risk factors, more mimics, and substantially worsened outcomes compared to community-onset strokes. The fact that these strokes manifest during the acute care hospitalization, in patients with higher rates of thrombolytic contraindications, creates distinct challenges for treatment. However, the best evidence suggests benefit to treating appropriately selected in-hospital ischemic strokes with thrombolysis. Evidence points toward a “quality gap” for in-hospital stroke with longer in-hospital delays to evaluation and treatment, lower rates of evaluation for etiology, and decreased adherence to consensus quality process measures of care. This quality gap for in-hospital stroke represents a focused opportunity for quality improvement. PMID:26288675

  9. [Pathophysiology of ischemic cardiac pain.].

    PubMed

    Münzel, T; Bassenge, E

    1988-09-01

    Cardiac pain is a conscious experience that can be explored only indirectly with experimental approaches. The exact machanisms eliciting cardiac pain still remain obscure. The afferent fibres running in the cardiac sympathetic nerves are regarded as the essential pathway for the transmission of cardiac pain. Atria and ventricle are abundantly supplied with sympathetic sensory innervation. In the spinal cord, impulses transmitted by the sympathetic pathway converge with impulses from somatic thoracic structures onto the same ascending spinothalamic neuron which probably explains the mechanism of referred pain (=projection of pain to another organ). Two hypotheses have been put forward to explain the peripheral mechanism for nociception. The intensity mechanism assumes that pain results from an excessive stimulation of receptive structures normally stimulated at lower levels whereas a specific sensation is considered to result from an excitation of a well defined nociceptive apparatus. Ventricular sympathetic afferent fibres whether myelinated or unmyelinated, always possess some mechanosensitivity and respond to normal chemical and mechanical stimuli, thus displaying properties of polymodal receptors. Afferent vagal fibres may contribute to the mechanisms of cardiac nociception by modulating the threshold and characteristics of pain. Experimental studies identified three main mechanisms, which may be responsible for eliciting cardiac pain during ischemic periods in humans: a) nonphysiological motion of the ischemic left ventricular wall (bulging) and an excitation of mechanical receptors by passive stretching. b) The excitation of free sensory nerve endings by chemicals such as bradykinin, PGE(2), adenosin, histamin or potassium. c) A combination of a and b: algogenic chemicals may sensitize mechanical receptors and therefore lower their threshold for nociception. PMID:18415323

  10. Ischemic post-conditioning to counteract intestinal ischemia/reperfusion injury

    PubMed Central

    Guan, Yan-Fang; Pritts, Timothy A; Montrose, Marshall H

    2010-01-01

    Intestinal ischemia is a severe disorder with a variety of causes. Reperfusion is a common occurrence during treatment of acute intestinal ischemia but the injury resulting from ischemia/reperfusion (IR) may lead to even more serious complications from intestinal atrophy to multiple organ failure and death. The susceptibility of the intestine to IR-induced injury (IRI) appears from various experimental studies and clinical settings such as cardiac and major vascular surgery and organ transplantation. Whereas oxygen free radicals, activation of leukocytes, failure of microvascular perfusion, cellular acidosis and disturbance of intracellular homeostasis have been implicated as important factors in the pathogenesis of intestinal IRI, the mechanisms underlying this disorder are not well known. To date, increasing attention is being paid in animal studies to potential pre- and post-ischemia treatments that protect against intestinal IRI such as drug interference with IR-induced apoptosis and inflammation processes and ischemic pre-conditioning. However, better insight is needed into the molecular and cellular events associated with reperfusion-induced damage to develop effective clinical protection protocols to combat this disorder. In this respect, the use of ischemic post-conditioning in combination with experimentally prolonged acidosis blocking deleterious reperfusion actions may turn out to have particular clinical relevance. PMID:21607154

  11. Standardization efforts in IP telephony

    NASA Astrophysics Data System (ADS)

    Sengodan, Senthil; Bansal, Raj

    1999-11-01

    The recent interest in IP telephony has led to a tremendous increase of standardization activities in the area. The three main standards bodies in the area of IP telephony are the International Telecommunication Union's (ITU-T) Study Group (SG) 16, the Internet Engineering Task Force (IETF) and the European Telecommunication Standards Institute's (ETSI) TIPHON project. In addition, forums such as the International Multimedia Teleconferencing Consortium (IMTC), the Intelligent Network Forum (INF), the International Softswitch Consortium (ISC), the Electronic Computer Telephony Forum (ECTF), and the MIT's Internet Telephony Consortium (ITC) are looking into various other aspects that aim at the growth of this industry. This paper describes the main tasks (completed and in progress) undertaken by these organizations. In describing such work, an overview of the underlying technology is also provided.

  12. Mobile-ip Aeronautical Network Simulation Study

    NASA Technical Reports Server (NTRS)

    Ivancic, William D.; Tran, Diepchi T.

    2001-01-01

    NASA is interested in applying mobile Internet protocol (mobile-ip) technologies to its space and aeronautics programs. In particular, mobile-ip will play a major role in the Advanced Aeronautic Transportation Technology (AATT), the Weather Information Communication (WINCOMM), and the Small Aircraft Transportation System (SATS) aeronautics programs. This report presents the results of a simulation study of mobile-ip for an aeronautical network. The study was performed to determine the performance of the transmission control protocol (TCP) in a mobile-ip environment and to gain an understanding of how long delays, handoffs, and noisy channels affect mobile-ip performance.

  13. Protection of Ischemic Postconditioning against Neuronal Apoptosis Induced by Transient Focal Ischemia Is Associated with Attenuation of NF-?B/p65 Activation

    PubMed Central

    Liang, Jianmin; Luan, Yongxin; Lu, Bin; Zhang, Hongbo; Luo, Yi-nan; Ge, Pengfei

    2014-01-01

    Background and Purpose Accumulating evidences have demonstrated that nuclear factor ?B/p65 plays a protective role in the protection of ischemic preconditioning and detrimental role in lethal ischemia-induced programmed cell death including apoptosis and autophagic death. However, its role in the protection of ischemic postconditioning is still unclear. Methods Rat MCAO model was used to produce transient focal ischemia. The procedure of ischemic postconditioning consisted of three cycles of 30 seconds reperfusion/reocclusion of MCA. The volume of cerebral infarction was measured by TTC staining and neuronal apoptosis was detected by TUNEL staining. Western blotting was used to analyze the changes in protein levels of Caspase-3, NF-?B/p65, phosphor- NF-?B/p65, I?B?, phosphor- I?B?, Noxa, Bim and Bax between rats treated with and without ischemic postconditioning. Laser scanning confocal microscopy was used to examine the distribution of NF-?B/p65 and Noxa. Results Ischemic postconditioning made transient focal ischemia-induced infarct volume decrease obviously from 38.6%±5.8% to 23.5%±4.3%, and apoptosis rate reduce significantly from 46.5%±6.2 to 29.6%±5.3% at reperfusion 24 h following 2 h focal cerebral ischemia. Western blotting analysis showed that ischemic postconditioning suppressed markedly the reduction of NF-?B/p65 in cytoplasm, but elevated its content in nucleus either at reperfusion 6 h or 24 h. Moreover, the decrease of I?B? and the increase of phosphorylated I?B? and phosphorylated NF-?B/p65 at indicated reperfusion time were reversed by ischemic postconditioning. Correspondingly, proapoptotic proteins Caspase-3, cleaved Caspase-3, Noxa, Bim and Bax were all mitigated significantly by ischemic postconditioning. Confocal microscopy revealed that ischemic postconditioning not only attenuated ischemia-induced translocation of NF-?B/p65 from neuronal cytoplasm to nucleus, but also inhibited the abnormal expression of proapoptotic protein Noxa within neurons. Conclusions We demonstrated in this study that the protection of ischemic postconditioning on neuronal apoptosis caused by transient focal ischemia is associated with attenuation of the activation of NF-?B/p65 in neurons. PMID:24800741

  14. OSI and TCP/IP

    NASA Technical Reports Server (NTRS)

    Randolph, Lynwood P.

    1994-01-01

    The Open Systems Interconnection Transmission Control Protocol/Internet Protocol (OSI TCP/IP) and the Government Open Systems Interconnection Profile (GOSIP) are compared and described in terms of Federal internetworking. The organization and functions of the Federal Internetworking Requirements Panel (FIRP) are discussed and the panel's conclusions and recommendations with respect to the standards and implementation of the National Information Infrastructure (NII) are presented.

  15. Advanced Networking Voice over IP

    E-print Network

    Lo Cigno, Renato Antonio

    Advanced Networking ­ VoIP 8 #12;locigno@disi.unitn.it "A" Compression Law ( ) ( ) ( ) ( ) + + + = AX A X X A A Y ln1 ln1 sgn ln1 law A -1 -0.5 0 0.5 1 -1 -0.5 0 0.5 1 11 1 is still biased by the original monopoly system The structure was tailored and optimized for voice

  16. Advanced Networking Voice over IP

    E-print Network

    Lo Cigno, Renato Antonio

    are not uniform across coutries. Architecture is still biased by the original monopoly system The structure Renato.LoCigno@disi.unitn.it Advanced Networking ­ VoIP - 1 11 "A" Compression Law ( ) ( ) ( ) ( ) + + + = AX A X X A A Y ln1 ln1 sgn ln1 law A -1 -0.5 0 0.5 1 -1 -0.5 0 0.5 1 11 1

  17. Advanced Networking Voice over IP

    E-print Network

    Lo Cigno, Renato Antonio

    by the original monopoly system The structure was tailored and optimized for voice transport Local Exchange #12;Renato.LoCigno@disi.unitn.it Advanced Networking ­ VoIP: Intro/H.323 11 "A" Compression Law ( ) ( ) ( ) ( ) + + + = AX A X X A A Y ln1 ln1 sgn ln1 law A -1 -0.5 0 0.5 1 -1 -0.5 0 0.5 1 11 1

  18. Neuroprotective Mechanisms of Taurine against Ischemic Stroke

    PubMed Central

    Menzie, Janet; Prentice, Howard; Wu, Jang-Yen

    2013-01-01

    Ischemic stroke exhibits a multiplicity of pathophysiological mechanisms. To address the diverse pathophysiological mechanisms observed in ischemic stroke investigators seek to find therapeutic strategies that are multifaceted in their action by either investigating multipotential compounds or by using a combination of compounds. Taurine, an endogenous amino acid, exhibits a plethora of physiological functions. It exhibits antioxidative properties, stabilizes membrane, functions as an osmoregulator, modulates ionic movements, reduces the level of pro-inflammators, regulates intracellular calcium concentration; all of which contributes to its neuroprotective effect. Data are accumulating that show the neuroprotective mechanisms of taurine against stroke pathophysiology. In this review, we describe the neuroprotective mechanisms employed by taurine against ischemic stroke and its use in clinical trial for ischemic stroke. PMID:24961429

  19. IP Profiling via Service Cluster Membership Vectors

    SciTech Connect

    Bartoletti, A

    2009-02-23

    This study investigates the feasibility of establishing and maintaining a system of compact IP behavioral profiles as a robust means of computer anomaly definition and detection. These profiles are based upon the degree to which a system's (IP's) network traffic is distributed among stable characteristic clusters derived of the aggregate session traffic generated by each of the major network services. In short, an IP's profile represents its degree of membership in these derived service clusters. The goal is to quantify and rank behaviors that are outside of the statistical norm for the services in question, or present significant deviation from profile for individual client IPs. Herein, we establish stable clusters for accessible features of common session traffic, migrate these clusters over time, define IP behavior profiles with respect to these clusters, migrate individual IP profiles over time, and demonstrate the detection of IP behavioral changes in terms of deviation from profile.

  20. Torsades de Pointes due to ischemic stroke.

    PubMed

    Ocak, Tarik; Duran, Arif; Tekelioglu, Umit Yasar; Erdem, Alim; Dagistan, Emine

    2013-08-01

    Cardiac and cerebrovascular illnesses are among the leading causes of mortality and morbidity today. Thromboembolic cases, which are the result of cardiac arrhythmia, are one of the important causes of cerebral stroke. However, various abnormalities, especially ST-T wave changes on electrocardiography can be seen in patients who do not have any heart disease history but had ischemic cerebral stroke. In this study, we have presented an interesting case of Torsades de Pointes due to ischemic cerebral stroke. PMID:23892870

  1. Angiotensinogen polymorphism and ischemic stroke risk

    PubMed Central

    Bao, Huan; Hao, Jun-Jie; Yang, Yu-Mei; Xu, Xia-Hong; Wang, Yue; Zuo, Lian; Lu, Jing; Zhang, Jing; Zhang, Yue; Xu, Si-Yi; Wang, Xuan; Li, Ying; Li, Gang

    2015-01-01

    The angiotensinogen M235T polymorphism was associated with ischemic stroke risk. However, the results were controversial. Thus, a meta-analysis was conducted. NCBI, Medline, Web of Science and Embase databases were systematically searched. Summary odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were estimated using random-effects models. There was a significant association between angiotensinogen M235T polymorphism and ischemic stroke risk (OR = 1.69; 95% CI, 1.35-2.11; P < 0.001). In the stratified analysis by ethnicity, we found that this polymorphism was significantly associated with ischemic stroke in Asian (OR = 1.85; 95% CI, 1.45-2.35; P < 0.001). In the age subgroup, we found that angiotensinogen M235T polymorphism could increase both early-onset ischemic stroke risk (OR = 1.88; 95% CI, 1.33-2.43; P < 0.001) and late-onset ischemic stroke risk (OR = 1.20; 95% CI, 1.01-1.39; P = 0.04). This meta-analysis suggested that angiotensinogen M235T polymorphism was associated with ischemic stroke. PMID:26550208

  2. Ischemic stroke associated with immune thrombocytopenia.

    PubMed

    Zhao, HongMei; Lian, YaJun; Zhang, HaiFeng; Xie, NanChang; Gao, YanLun; Wang, ZhongYue; Zhang, Yi

    2015-08-01

    The objective of this study was to review all cases in literature in which the clinical manifestations of ischemic stroke and immune thrombocytopenia (ITP) were presented in the same patient including a new case of our own and discuss the possible mechanism and management of this syndrome. We reviewed 12 reports in which 18 cases were diagnosed as ischemic stroke and ITP. The clinical manifestations and ischemic lesion patterns of the 18 cases and our new case were analyzed in detail to elucidate the characteristics and management of this kind of syndrome. Of all the cases, 8 females and 10 males, 10 of them were Koreans; 3 were Americans; 3 were Japanese; 1 was British and 1 was Australian. The age of eight patients was no more than 50 years old. Most of them had a low platelet count. CT and/or MRI of brain were seen in all tested cases. Prognosis of ischemic stroke was good in 18 of the 19 patients. Although extremely rare, ischemic stroke and ITP may present in the same patient with variant characteristics. This paradoxical mechanism and management of ischemic stroke associated with ITP requires further investigation. PMID:25381164

  3. First Experimental Demonstration of IP-client-to-IP-client Video Streaming Application over an All-Optical Label-

    E-print Network

    Yoo, S. J. Ben

    First Experimental Demonstration of IP-client-to-IP-client Video Streaming Application over an All knowledge, successful transmission and switching of video streaming traffic from an IP-client to an IP-client format clients or client networks. Seamless and ubiquitous IP client-to-IP client connections

  4. Hypoxic preconditioning and cell death from oxygen/glucose deprivation co-opt a subset of the unfolded protein response in hippocampal neurons.

    PubMed

    Bickler, P E; Clark, J P; Gabatto, P; Brosnan, H

    2015-12-01

    The state of protein folding in the endoplasmic reticulum (ER), via the unfolded protein response (UPR), regulates a pro- or anti-apoptotic cell fate. Hypoxic preconditioning (HPC) is a potent anti-apoptotic stimulus, wherein ischemic neural injury is averted by a non-damaging exposure to hypoxia. We tested if UPR modulation contributes to the pro-survival/anti-apoptotic phenotype in neurons preconditioned with hypoxia, using organotypic cultures of rat hippocampus as a model system. Pharmacologic induction of the UPR with tunicamycin increased mRNA of 79 of 84 UPR genes and replicated the pro-survival phenotype of HPC, whereas only small numbers of the same mRNAs were upregulated at 0, 6 and 24h after HPC. During the first 24h after HPC, protein signals in all 3 UPR pathways increased at various times: increased ATF4, phosphorylation of eif2? and IRE1, cleavage of xbb1 mRNA and cleavage of ATF6. Pharmacologic inhibition of ATF6 and IRE1 blocked HPC. Ischemia-like conditions (oxygen/glucose deprivation, OGD) caused extensive neuron cell damage and involved some of the same UPR protein signals as HPC. In distinction to HPC and tunicamycin, OGD caused widespread suppression of UPR genes: 55 of 84 UPR gene mRNAs were numerically downregulated. We conclude that although HPC and ischemic cell death in hippocampal neurons involve protein-based signaling in all 3 UPR pathways, these processes co-opt only a subset of the genomic response elicited by agents known to cause protein misfolding, possibly because of persistent transcription/translation arrest induced by hypoxia and especially OGD. PMID:26404874

  5. Sulforaphane preconditioning of the Nrf2/HO-1 defense pathway protects the cerebral vasculature against blood-brain barrier disruption and neurological deficits in stroke.

    PubMed

    Alfieri, Alessio; Srivastava, Salil; Siow, Richard C M; Cash, Diana; Modo, Michel; Duchen, Michael R; Fraser, Paul A; Williams, Steven C R; Mann, Giovanni E

    2013-12-01

    Disruption of the blood-brain barrier (BBB) and cerebral edema are the major pathogenic mechanisms leading to neurological dysfunction and death after ischemic stroke. The brain protects itself against infarction via activation of endogenous antioxidant defense mechanisms, and we here report the first evidence that sulforaphane-mediated preactivation of nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream target heme oxygenase-1 (HO-1) in the cerebral vasculature protects the brain against stroke. To induce ischemic stroke, Sprague-Dawley rats were subjected to 70 min middle cerebral artery occlusion (MCAo) followed by 4, 24, or 72 h reperfusion. Nrf2 and HO-1 protein expression was upregulated in cerebral microvessels of peri-infarct regions after 4-72 h, with HO-1 preferentially associated with perivascular astrocytes rather than the cerebrovascular endothelium. In naïve rats, treatment with sulforaphane increased Nrf2 expression in cerebral microvessels after 24h. Upregulation of Nrf2 by sulforaphane treatment prior to transient MCAo (1h) was associated with increased HO-1 expression in perivascular astrocytes in peri-infarct regions and cerebral endothelium in the infarct core. BBB disruption, lesion progression, as analyzed by MRI, and neurological deficits were reduced by sulforaphane pretreatment. As sulforaphane pretreatment led to a moderate increase in peroxynitrite generation, we suggest that hormetic preconditioning underlies sulforaphane-mediated protection against stroke. In conclusion, we propose that pharmacological or dietary interventions aimed to precondition the brain via activation of the Nrf2 defense pathway in the cerebral microvasculature provide a novel therapeutic approach for preventing BBB breakdown and neurological dysfunction in stroke. PMID:24017972

  6. Shape reanalysis and sensitivities utilizing preconditioned iterative boundary solvers

    NASA Technical Reports Server (NTRS)

    Guru Prasad, K.; Kane, J. H.

    1992-01-01

    The computational advantages associated with the utilization of preconditined iterative equation solvers are quantified for the reanalysis of perturbed shapes using continuum structural boundary element analysis (BEA). Both single- and multi-zone three-dimensional problems are examined. Significant reductions in computer time are obtained by making use of previously computed solution vectors and preconditioners in subsequent analyses. The effectiveness of this technique is demonstrated for the computation of shape response sensitivities required in shape optimization. Computer times and accuracies achieved using the preconditioned iterative solvers are compared with those obtained via direct solvers and implicit differentiation of the boundary integral equations. It is concluded that this approach employing preconditioned iterative equation solvers in reanalysis and sensitivity analysis can be competitive with if not superior to those involving direct solvers.

  7. Exercise and Cardiac Preconditioning Against Ischemia Reperfusion Injury

    PubMed Central

    Quindry, John C; Hamilton, Karyn L

    2013-01-01

    Cardiovascular disease (CVD), including ischemia reperfusion (IR) injury, remains a major cause of morbidity and mortality in industrialized nations. Ongoing research is aimed at uncovering therapeutic interventions against IR injury. Regular exercise participation is recognized as an important lifestyle intervention in the prevention and treatment of CVD and IR injury. More recent understanding reveals that moderate intensity aerobic exercise is also an important experimental model for understanding the cellular mechanisms of cardioprotection against IR injury. An important discovery in this regard was the observation that one-to-several days of exercise will attenuate IR injury. This phenomenon has been observed in young and old hearts of both sexes. Due to the short time course of exercise induced protection, IR injury prevention must be mediated by acute biochemical alterations within the myocardium. Research over the last decade reveals that redundant mechanisms account for exercise induced cardioprotection against IR. While much is now known about exercise preconditioning against IR injury, many questions remain. Perhaps most pressing, is what mechanisms mediate cardioprotection in aged hearts and what sex-dependent differences exist. Given that that exercise preconditioning is a polygenic effect, it is likely that multiple mediators of exercise induced cardioprotection have yet to be uncovered. Also unknown, is whether post translational modifications due to exercise are responsible for IR injury prevention. This review will provide an overview the major mechanisms of IR injury and exercise preconditioning. The discussion highlights many promising avenues for further research and describes how exercise preconditioning may continue to be an important scientific paradigm in the translation of cardioprotection research to the clinic. PMID:23909636

  8. Parallel Domain Decomposition Preconditioning for Computational Fluid Dynamics

    NASA Technical Reports Server (NTRS)

    Barth, Timothy J.; Chan, Tony F.; Tang, Wei-Pai; Kutler, Paul (Technical Monitor)

    1998-01-01

    This viewgraph presentation gives an overview of the parallel domain decomposition preconditioning for computational fluid dynamics. Details are given on some difficult fluid flow problems, stabilized spatial discretizations, and Newton's method for solving the discretized flow equations. Schur complement domain decomposition is described through basic formulation, simplifying strategies (including iterative subdomain and Schur complement solves, matrix element dropping, localized Schur complement computation, and supersparse computations), and performance evaluation.

  9. Preconditioned solenoidal basis method for incompressible fluid flows 

    E-print Network

    Wang, Xue

    2006-04-12

    and content by: Vivek Sarin (Chair of Committee) Andreas Klappenecker (Member) Hamn-Ching Chen (Member) Valerie E. Taylor (Head of Department) December 2004 Major Subject: Computer Science iii ABSTRACT Preconditioned Solenoidal Basis Method for Incompressible... of this research and thesis. This thesis would not have been completed without his help. I would also like to thank my committee members Dr. Hamn-Ching Chen and Dr. Andreas Klappenecker for their help, support and valuable suggestions. A special thank...

  10. Novel cardioprotective strategy combining three different preconditioning methods to prevent ischemia/reperfusion injury in aged hearts in an improved rabbit model

    PubMed Central

    YE, JIAN-XI; CHEN, DAO-ZHONG

    2015-01-01

    The use of ischemic preconditioning (IPC) to protect the myocardium is usually not effective in elderly patients. The aim of the present study was to design new methods to achieve enhanced myocardial protection, based on the differential role of endogenous adenosine (ADO) and ADO receptors (ARs) in the effects of IPC on young and old animals. An improved New Zealand white rabbit model of ischemia/reperfusion was established based on the Langendorff model. Adult or elderly rabbit hearts, with or without exposure to IPC, were used in order to assess the roles of ADO and ARs in the different effects of IPC. Different protective methods were designed based on a combination of endogenous and exogenous interventions. Cardiac function, as well as biochemical, histopathological and apoptotic indices, were measured in the different intervention groups. The improved Langendorff model was stable, reliable and suitable for the undertaking of the experiments. The ADO levels in the aged rabbit hearts pre- and post-IPC were lower than those in the adult hearts, indicating that ADO levels may be an endogenous factor influencing IPC. A new protection strategy combining ADO-enhanced IPC, A1AR agonist 2-chloro-N(6)-cyclopentyladenosine preconditioning and cold crystalloid cardioplegia had a significant protective effect in aged hearts. The results of the present study suggested that endogenous ADO enhancement, A1AR agonist preconditioning and exogenous treatment yield an additive effect in aged rabbit hearts. The simultaneous application of these three types of intervention provided the most effective myocardial protection in the improved aged rabbit heart model. PMID:26622489

  11. Nitroxyl exacerbates ischemic cerebral injury and oxidative neurotoxicity.

    PubMed

    Choe, Chi-un; Lewerenz, Jan; Fischer, Gerry; Uliasz, Tracy F; Espey, Michael Graham; Hummel, Friedhelm C; King, Stephen Bruce; Schwedhelm, Edzard; Böger, Rainer H; Gerloff, Christian; Hewett, Sandra J; Magnus, Tim; Donzelli, Sonia

    2009-09-01

    Nitroxyl (HNO) donor compounds function as potent vasorelaxants, improve myocardial contractility and reduce ischemia-reperfusion injury in the cardiovascular system. With respect to the nervous system, HNO donors have been shown to attenuate NMDA receptor activity and neuronal injury, suggesting that its production may be protective against cerebral ischemic damage. Hence, we studied the effect of the classical HNO-donor, Angeli's salt (AS), on a cerebral ischemia/reperfusion injury in a mouse model of experimental stroke and on related in vitro paradigms of neurotoxicity. I.p. injection of AS (40 mumol/kg) in mice prior to middle cerebral artery occlusion exacerbated cortical infarct size and worsened the persistent neurological deficit. AS not only decreased systolic blood pressure, but also induced systemic oxidative stress in vivo indicated by increased isoprostane levels in urine and serum. In vitro, neuronal damage induced by oxygen-glucose-deprivation of mature neuronal cultures was exacerbated by AS, although there was no direct effect on glutamate excitotoxicity. Finally, AS exacerbated oxidative glutamate toxicity - that is, cell death propagated via oxidative stress in immature neurons devoid of ionotropic glutamate receptors. Taken together, our data indicate that HNO might worsen cerebral ischemia-reperfusion injury by increasing oxidative stress and decreasing brain perfusion at concentrations shown to be cardioprotective in vivo. PMID:19619135

  12. Islet preconditioning via multimodal microfluidic modulation of intermittent hypoxia.

    PubMed

    Lo, Joe F; Wang, Yong; Blake, Alexander; Yu, Gene; Harvat, Tricia A; Jeon, Hyojin; Oberholzer, Jose; Eddington, David T

    2012-02-21

    Simultaneous stimulation of ex vivo pancreatic islets with dynamic oxygen and glucose is a critical technique for studying how hypoxia alters glucose-stimulated response, especially in transplant environments. Standard techniques using a hypoxic chamber cannot provide both oxygen and glucose modulations, while monitoring stimulus-secretion coupling factors in real-time. Using novel microfluidic device with integrated glucose and oxygen modulations, we quantified hypoxic impairment of islet response by calcium influx, mitochondrial potentials, and insulin secretion. Glucose-induced calcium response magnitude and phase were suppressed by hypoxia, while mitochondrial hyperpolarization and insulin secretion decreased in coordination. More importantly, hypoxic response was improved by preconditioning islets to intermittent hypoxia (IH, 1 min/1 min 5-21% cycling for 1 h), translating to improved insulin secretion. Moreover, blocking mitochondrial K(ATP) channels removed preconditioning benefits of IH, similar to mechanisms in preconditioned cardiomyocytes. Additionally, the multimodal device can be applied to a variety of dynamic oxygen-metabolic studies in other ex vivo tissues. PMID:22296179

  13. Preconditioning the bidomain model with almost linear complexity

    NASA Astrophysics Data System (ADS)

    Pierre, Charles

    2012-01-01

    The bidomain model is widely used in electro-cardiology to simulate spreading of excitation in the myocardium and electrocardiograms. It consists of a system of two parabolic reaction diffusion equations coupled with an ODE system. Its discretisation displays an ill-conditioned system matrix to be inverted at each time step: simulations based on the bidomain model therefore are associated with high computational costs. In this paper we propose a preconditioning for the bidomain model either for an isolated heart or in an extended framework including a coupling with the surrounding tissues (the torso). The preconditioning is based on a formulation of the discrete problem that is shown to be symmetric positive semi-definite. A block LU decomposition of the system together with a heuristic approximation (referred to as the monodomain approximation) are the key ingredients for the preconditioning definition. Numerical results are provided for two test cases: a 2D test case on a realistic slice of the thorax based on a segmented heart medical image geometry, a 3D test case involving a small cubic slab of tissue with orthotropic anisotropy. The analysis of the resulting computational cost (both in terms of CPU time and of iteration number) shows an almost linear complexity with the problem size, i.e. of type nlog ?( n) (for some constant ?) which is optimal complexity for such problems.

  14. Analysis of Handoff Mechanisms in Mobile IP

    NASA Astrophysics Data System (ADS)

    Jayaraj, Maria Nadine Simonel; Issac, Biju; Haldar, Manas Kumar

    2011-06-01

    One of the most important challenges in mobile Internet Protocol (IP) is to provide service for a mobile node to maintain its connectivity to network when it moves from one domain to another. IP is responsible for routing packets across network. The first major version of IP is the Internet Protocol version 4 (IPv4). It is one of the dominant protocols relevant to wireless network. Later a newer version of IP called the IPv6 was proposed. Mobile IPv6 is mainly introduced for the purpose of mobility. Mobility management enables network to locate roaming nodes in order to deliver packets and maintain connections with them when moving into new domains. Handoff occurs when a mobile node moves from one network to another. It is a key factor of mobility because a mobile node can trigger several handoffs during a session. This paper briefly explains on mobile IP and its handoff issues, along with the drawbacks of mobile IP.

  15. Dual antiplatelet therapy after noncardioembolic ischemic stroke or transient ischemic attack: pros and cons.

    PubMed

    Hong, Keun-Sik

    2014-07-01

    Dual antiplatelet therapy simultaneously blocks different platelet activation pathways and might thus be more potent at inhibiting platelet activation and more effective at reducing major ischemic vascular events compared to antiplatelet monotherapy. Aspirin plus clopidogrel dual therapy is now the standard therapy for patients with acute coronary syndrome and for those undergoing percutaneous coronary intervention. However, dual antiplatelet therapy carries an increased risk of bleeding. Patients with ischemic stroke or transient ischemic attack (TIA) are generally older and likely to have a fragile cerebrovascular bed, which further increases the risk of systemic major bleeding events and intracranial hemorrhage. Clinical trials and meta-analyses suggest that in comparison to antiplatelet monotherapy, dual antiplatelet therapy initiated early after noncardioembolic ischemic stroke or TIA further reduces the rate of recurrent stroke and major vascular events without significantly increasing the rate of major bleeding events. In contrast, studies of long-term therapy in patients with noncardioembolic ischemic stroke or TIA have yielded inconsistent data regarding the benefit of dual antiplatelet therapy over monotherapy. However, the harm associated with major bleeding events, including intracranial hemorrhage, which is generally more disabling and more fatal than ischemic stroke, is likely to increase with dual antiplatelet therapy. Physicians should carefully assess the benefits and risks of dual antiplatelet therapy versus antiplatelet monotherapy when managing patients with ischemic stroke or TIA. PMID:25045370

  16. Population Genetics of Spruce Bark Beetle Ips typographus (Col., Scolytidae) and Related Ips Species1

    E-print Network

    Population Genetics of Spruce Bark Beetle Ips typographus (Col., Scolytidae) and Related Ips different species is the spruce bark beetle Ips amitinus. This relationship could be also demon- strated, in Europe, each of 1 An abbreviated version of this paper was presented at the Bark Beetle Genetic Workshop

  17. Spectroscopic monitoring of kidney tissue ischemic injury

    NASA Astrophysics Data System (ADS)

    Fitzgerald, Jason T.; Michalopoulou, Andromachi P.; Troppmann, Christoph; Demos, Stavros G.

    2004-07-01

    Noninvasive evaluation of tissue viability of donor kidneys used for transplantation is an issue that current technology is not able to address. In this work, we explore optical spectroscopy for its potential to assess the degree of ischemic damage in kidney tissue. We hypothesized that ischemic damage to kidney tissue will give rise to changes in its optical properties which in turn may be used to asses the degree of tissue injury. The experimental results demonstrate that the autofluorescence intensity of the injured kidney is decreasing as a function of time exposed to ischemic injury. Changes were also observed in the NIR light scattering intensities most probably arising from changes due to injury and death of the tissue.

  18. Spectroscopic Monitoring of Kidney Tissue Ischemic Injury

    SciTech Connect

    Demos, S G; Fitzgerald, J T; Michalopoulou, A P; Troppmann, C

    2004-03-11

    Noninvasive evaluation of tissue viability of donor kidneys used for transplantation is an issue that current technology is not able to address. In this work, we explore optical spectroscopy for its potential to assess the degree of ischemic damage in kidney tissue. We hypothesized that ischemic damage to kidney tissue will give rise to changes in its optical properties which in turn may be used to asses the degree of tissue injury. The experimental results demonstrate that the autofluorescence intensity of the injured kidney is decreasing as a function of time exposed to ischemic injury. Changes were also observed in the NIR light scattering intensities most probably arising from changes due to injury and death of the tissue.

  19. Infection in the ischemic lower extremity.

    PubMed

    Fry, D E; Marek, J M; Langsfeld, M

    1998-06-01

    Infections in the lower extremity of the patient with ischemia can cover a broad spectrum of different diseases. An understanding of the particular pathophysiologic circumstances in the ischemic extremity can be of great value in understanding the natural history of the disease and the potential complications that may occur. Optimizing blood flow to the extremity by using revascularization techniques is important for any patient with an ischemic lower extremity complicated by infection or ulceration. Infections in the ischemic lower extremity require local débridement and systemic antibiotics. For severe infections, such as necrotizing fasciitis or the fetid foot, more extensive local débridement and even amputation may be required. Fundamentals of managing prosthetic graft infection require removing the infected prosthesis, local wound débridement, and systemic antibiotics while attempting to preserve viability of the lower extremity using autogenous graft reconstruction. PMID:9673657

  20. Drug Delivery to the Ischemic Brain

    PubMed Central

    Thompson, Brandon J.; Ronaldson, Patrick T.

    2014-01-01

    Cerebral ischemia occurs when blood flow to the brain is insufficient to meet metabolic demand. This can result from cerebral artery occlusion that interrupts blood flow, limits CNS supply of oxygen and glucose, and causes an infarction/ischemic stroke. Ischemia initiates a cascade of molecular events inneurons and cerebrovascular endothelial cells including energy depletion, dissipation of ion gradients, calcium overload, excitotoxicity, oxidative stress, and accumulation of ions and fluid. Blood-brain barrier (BBB) disruption is associated with cerebral ischemia and leads to vasogenic edema, a primary cause of stroke-associated mortality. To date, only a single drug has received US Food and Drug Administration (FDA) approval for acute ischemic stroke treatment, recombinant tissue plasminogen activator (rt-PA). While rt-PA therapy restores perfusion to ischemic brain, considerable tissue damage occurs when cerebral blood flow is re-established. Therefore, there is a critical need for novel therapeutic approaches that can “rescue” salvageable brain tissue and/or protect BBB integrity during ischemic stroke. One class of drugs that may enable neural cell rescue following cerebral ischemia/reperfusion injury is the HMG-CoA reductase inhibitors (i.e., statins). Understanding potential CNS drug delivery pathways for statins is critical to their utility in ischemic stroke. Here, we review molecular pathways associated with cerebral ischemia and novel approaches for delivering drugs to treat ischemic disease. Specifically, we discuss utility of endogenous BBB drug uptake transporters such as organic anion transporting polypeptides (OATPs/Oatps) and nanotechnology-based carriers for optimization of CNS drug delivery. Overall, this chapter highlights state-of-the-art technologies that may improve pharmacotherapy of cerebral ischemia. PMID:25307217

  1. Drug delivery to the ischemic brain.

    PubMed

    Thompson, Brandon J; Ronaldson, Patrick T

    2014-01-01

    Cerebral ischemia occurs when blood flow to the brain is insufficient to meet metabolic demand. This can result from cerebral artery occlusion that interrupts blood flow, limits CNS supply of oxygen and glucose, and causes an infarction/ischemic stroke. Ischemia initiates a cascade of molecular events in neurons and cerebrovascular endothelial cells including energy depletion, dissipation of ion gradients, calcium overload, excitotoxicity, oxidative stress, and accumulation of ions and fluid. Blood-brain barrier (BBB) disruption is associated with cerebral ischemia and leads to vasogenic edema, a primary cause of stroke-associated mortality. To date, only a single drug has received US Food and Drug Administration (FDA) approval for acute ischemic stroke treatment, recombinant tissue plasminogen activator (rt-PA). While rt-PA therapy restores perfusion to ischemic brain, considerable tissue damage occurs when cerebral blood flow is reestablished. Therefore, there is a critical need for novel therapeutic approaches that can "rescue" salvageable brain tissue and/or protect BBB integrity during ischemic stroke. One class of drugs that may enable neural cell rescue following cerebral ischemia/reperfusion injury is the HMG-CoA reductase inhibitors (i.e., statins). Understanding potential CNS drug delivery pathways for statins is critical to their utility in ischemic stroke. Here, we review molecular pathways associated with cerebral ischemia and novel approaches for delivering drugs to treat ischemic disease. Specifically, we discuss utility of endogenous BBB drug uptake transporters such as organic anion transporting polypeptides and nanotechnology-based carriers for optimization of CNS drug delivery. Overall, this chapter highlights state-of-the-art technologies that may improve pharmacotherapy of cerebral ischemia. PMID:25307217

  2. Empirical Tests of Anonymous Voice Over IP Marc Liberatoreb,

    E-print Network

    Wright , Matthew

    for extending onion-routing style anonymity protocols for supporting anonymous VoIP (aVoIP) traffic show that aVoIP could be developed in an onion routing system with reasonable performance guarantees Proxy Proxy Contact Anonymous Voice over IP (aVoIP) Initiator Proxy Proxy Proxy The Onion Router (Tor

  3. Preconditioning with glycyrrhizic, ferulic, paeoniflorin, cinnamic prevents rat hearts from ischemia/reperfusion injury via endothelial nitric oxide pathway

    PubMed Central

    Qian, Guo-Qiang; Ding, Jingjing; Zhang, Xiaozhao; Yin, Xiaofeng; Gao, Yuqin; Zhao, Guo-Ping

    2015-01-01

    Objective: The objective was to investigate the endothelial nitric oxide synthase (eNOS/NO) pathway is involved or not in the protective effects of glycyrrhizic, ferulic, paeoniflorin, cinnamic (GFPC) in myocardial ischemia-reperfusion injury Sprague-Dawley rats. Materials and Methods: Ischemia-reperfusion (I/R) model was made by ligating the left anterior descending branch of the coronary artery for 30 min and releasing for 120 min, then the left ventricular apical was fixed and sliced, morphological changes of myocardial microvascular endothelial cell (MMVEC) was observed by electron microscopy, apoptosis index of MMVEC was observed by means of TUNEL, serum NO was tested by methods of nitrate reduction, lactate dehydrogenase (LDH), creatine kinase MB (CK-MB) was detected by automatic biochemical analyzer; Phosphorylated eNOS (PeNOS) and inducible NOS (iNOS) protein were measured by means of western blot. Results: In positive product control group, the serum levels of NO, LDH, CK-MB significantly increased (P < 0.05); MMVEC apoptosis was significantly decreased (P < 0.05); incidence of area at risk decreased significantly (P < 0.05); PeNOS protein increased (P < 0.05); iNOS protein decreased significantly (P < 0.05). Conclusion: Ischemic preconditioning of GFPC from GFPC plays a protective role in I/R heart through regulating the eNOS/NO signal pathway by increasing the PeNOS protein expression and decreasing the expression of iNOS protein. PMID:25829767

  4. Flow Augmentation in Acute Ischemic Stroke.

    PubMed

    Yadollahikhales, Golnaz; Borhani-Haghighi, Afshin; Torabi-Nami, Mohammad; Edgell, Randall; Cruz-Flores, Salvador

    2016-01-01

    There is an urgent need for additional therapeutic options for acute ischemic stroke considering the major pitfalls of the options available. Herein, we briefly review the role of cerebral blood flow, collaterals, vasoreactivity, and reperfusion injury in acute ischemic stroke. Then, we reviewed pharmacological and interventional measures such as volume expansion and induced hypertension, intra-aortic balloon counterpulsation, partial aortic occlusion, extracranial-intracranial carotid bypass surgery, sphenopalatine ganglion stimulation, and transcranial laser therapy with regard to their effects on flow augmentation and neuroprotection. PMID:25475112

  5. RESEARCH & INNOVATION OFFICE EASY ACCESS IP

    E-print Network

    University of Technology, Sydney

    IP AT UTS UTS is dedicated to the discovery and dissemination of knowledge and to delivering impact doing business with us has become even easier. University technology is often at a very early stage impact. Universities have limited resources to develop IP to a stage of significant commercial value

  6. RESEARCH & INNOVATION OFFICE EASY ACCESS IP

    E-print Network

    University of Technology, Sydney

    transfer benefits Easy Access IP brings, this new approach will also help cement us as an institution of Bristol to promote new ways of sharing intellectual property (IP) and adopt new approaches to make it easier for universities and industry to work together. The University of New South Wales (UNSW

  7. IPS Observations at Miyun Station, BAO

    NASA Astrophysics Data System (ADS)

    Wu, J.; Zhang, X.; Zheng, Y.

    IPS observations have recently begun at Miyun Station, Beijing Astronomical Observatory. This paper briefly describes the radio telescope at Miyun Station, discusses the observation and the data reduction procedures, and presents the preliminary results of observations on IPS source 3C48.

  8. VoIP to the Rescue

    ERIC Educational Resources Information Center

    Milner, Jacob

    2005-01-01

    Voice over Internet Protocol (VoIP) is everywhere. The technology lets users make and receive phone calls over the Internet, transporting voice traffic alongside data traffic such as instant messages (IMs) and e-mail. While the number of consumer customers using VoIP increases every week, the technology is finding its way into K-12 education as…

  9. Approaches for Resolving Dynamic IP Addressing.

    ERIC Educational Resources Information Center

    Foo, Schubert; Hui, Siu Cheung; Yip, See Wai; He, Yulan

    1997-01-01

    A problem with dynamic Internet protocol (IP) addressing arises when the Internet connection is through an Internet provider since the IP address is allocated only at connection time. This article examines a number of online and offline methods for resolving the problem. Suggests dynamic domain name system (DNS) and directory service look-up are…

  10. Space Network IP Services (SNIS): An Architecture for Supporting Low Earth Orbiting IP Satellite Missions

    NASA Technical Reports Server (NTRS)

    Israel, David J.

    2005-01-01

    The NASA Space Network (SN) supports a variety of missions using the Tracking and Data Relay Satellite System (TDRSS), which includes ground stations in White Sands, New Mexico and Guam. A Space Network IP Services (SNIS) architecture is being developed to support future users with requirements for end-to-end Internet Protocol (IP) communications. This architecture will support all IP protocols, including Mobile IP, over TDRSS Single Access, Multiple Access, and Demand Access Radio Frequency (RF) links. This paper will describe this architecture and how it can enable Low Earth Orbiting IP satellite missions.

  11. 77 FR 33227 - Assessment Questionnaire-IP Sector Specific Agency Risk Self Assessment Tool (IP-SSARSAT)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-05

    ... SECURITY Assessment Questionnaire--IP Sector Specific Agency Risk Self Assessment Tool (IP-SSARSAT) AGENCY...--Assessment Questionnaire--IP Sector Specific Agency Risk Self Assessment Tool (IP-SSARSAT). DHS previously... Specific Agency Risk Self Assessment Tool (IP-SSARSAT). OMB Number: 1670-NEW. Frequency: On...

  12. DEMOMSTRATION OF IP CLIENT-TO-IP CLIENT PACKET TRANSPORT OVER AN OPTICAL LABEL-SWITCHING NETWORK

    E-print Network

    Yoo, S. J. Ben

    DEMOMSTRATION OF IP CLIENT-TO-IP CLIENT PACKET TRANSPORT OVER AN OPTICAL LABEL-SWITCHING NETWORK and routing of traffic from IP client-to-IP client through a multi-hop optical label-switching network. Edge routers generate optical labels and achieve interconnection between IP clients across the network

  13. Achieving quality of service in IP networks

    NASA Astrophysics Data System (ADS)

    Hays, Tim

    2001-07-01

    The Internet Protocol (IP) has served global networks well, providing a standardized method to transmit data among many disparate systems. But IP is designed for simplicity, and only enables a `best effort' service that can be subject to delays and loss of data. For data networks, this is an acceptable trade-off. In the emerging world of convergence, driven by new applications such as video streaming and IP telephony, minimizing latency and packet loss as well as jitter can be critical. Simply increasing the size of the IP network `pipe' to meet those demands is not always sufficient. In this environment, vendors and standards bodies are endeavoring to create technologies and techniques to enable IP to improve the quality of service it can provide, while retaining the characteristics that has enabled it to become the dominant networking protocol.

  14. SN2009ip at Very Late Times

    NASA Astrophysics Data System (ADS)

    Bigley, Andrew Christopher; Graham, Melissa Lynn

    2016-01-01

    The 2012 eruption of SN 2009ip resembled a Type IIn supernovae, dominated by emission from interaction of the ejecta with circumstellar material, but the question remains: was the 2012 outburst of SN 2009ip truly the terminal explosion of a massive star? We present time series photometric and spectroscopic data for the transient SN2009ip from 260 to 1026 days after the peak of its 2012 outburst. These data were collected at the Las Cumbres Observatory Global Telescope Network and Keck Observatory. We will show that SN 2009ip continues to decline linearly in brightness at very late epochs, analyze the evolution in flux and asymmetry of the Balmer emission lines, and investigate the geometry of the circumstellar material from the progenitor star system and the true nature of SN 2009ip.

  15. Weighted graph based ordering techniques for preconditioned conjugate gradient methods

    NASA Technical Reports Server (NTRS)

    Clift, Simon S.; Tang, Wei-Pai

    1994-01-01

    We describe the basis of a matrix ordering heuristic for improving the incomplete factorization used in preconditioned conjugate gradient techniques applied to anisotropic PDE's. Several new matrix ordering techniques, derived from well-known algorithms in combinatorial graph theory, which attempt to implement this heuristic, are described. These ordering techniques are tested against a number of matrices arising from linear anisotropic PDE's, and compared with other matrix ordering techniques. A variation of RCM is shown to generally improve the quality of incomplete factorization preconditioners.

  16. Preconditioning methods for ideal and multiphase fluid flows

    NASA Astrophysics Data System (ADS)

    Gupta, Ashish

    The objective of this study is to develop a preconditioning method for ideal and multiphase multispecies compressible fluid flow solver using homogeneous equilibrium mixture model. The mathematical model for fluid flow going through phase change uses density and temperature in the formulation, where the density represents the multiphase mixture density. The change of phase of the fluid is then explicitly determined using the equation of state of the fluid, which only requires temperature and mixture density. The method developed is based on a finite-volume framework in which the numerical fluxes are computed using Roe's approximate Riemann solver and the modified Harten, Lax and Van-leer scheme (HLLC). All speed Roe and HLLC flux based schemes have been developed either by using preconditioning or by directly modifying dissipation to reduce the effect of acoustic speed in its numerical dissipation when Mach number decreases. Preconditioning proposed by Briley, Taylor and Whitfield, Eriksson and Turkel are studied in this research, where as low dissipation schemes proposed by Rieper and Thornber, Mosedale, Drikakis, Youngs and Williams are also considered. Various preconditioners are evaluated in terms of development, performance, accuracy and limitations in simulations at various Mach numbers. A generalized preconditioner is derived which possesses well conditioned eigensystem for multiphase multispecies flow simulations. Validation and verification of the solution procedure are carried out on several small model problems with comparison to experimental, theoretical, and other numerical results. Preconditioning methods are evaluated using three basic geometries; 1) bump in a channel 2) flow over a NACA0012 airfoil and 3) flow over a cylinder, which are then compared with theoretical and numerical results. Multiphase capabilities of the solver are evaluated in cryogenic and non-cryogenic conditions. For cryogenic conditions the solver is evaluated by predicting cavitation on two basic geometries for which experimental data are available, that is, flow over simple foil and a quarter caliber hydrofoil in a tunnel using liquid nitrogen as a fluid. For non-cryogenic conditions, water near boiling conditions is used to predict cavitation on two simple geometries, that is, flow over simple foil in a tunnel and flow over a one caliber ogive. Cavitation predictions in both cryogenic and non-cryogenic cases are shows to agree well with available experimental data.

  17. Systemic corticosteroids in nonarteritic ischemic optic neuropathy

    PubMed Central

    Al-Zubidi, Nagham; Zhang, Jason; Spitze, Arielle; Lee, Andrew G

    2014-01-01

    Nonarteritic ischemic optic neuropathy (NAION) is one of the most prevalent optic nerve disorders seen in ophthalmic practice. The role of corticosteroid therapy in NAION remains a highly controversial area of debate in ophthalmology. This brief review will provide an overview of the current clinical evidence on this topic as well as some comment on the medical debate. PMID:25449939

  18. Cerebrovascular ischemic events in wind instrument players.

    PubMed

    Evers, S; Altenmüller, E; Ringelstein, E B

    2000-09-26

    Two cases of ischemic stroke due to carotid artery dissection occurring during wind instrument playing, probably caused by increased intrathoracic and subsequent intrapharyngeal pressure, are presented. A review of the literature revealed three similar patients with other types of cerebrovascular events, such as paradoxical cerebral embolism due to a patent foramen ovale and spinal epidural hematoma during trumpet playing. PMID:10994010

  19. Gene Therapy For Ischemic Heart Disease

    PubMed Central

    Lavu, Madhav; Gundewar, Susheel; Lefer, David J.

    2010-01-01

    Current pharmacologic therapy for ischemic heart disease suffers multiple limitations such as compliance issues and side effects of medications. Revascularization procedures often end with need for repeat procedures. Patients remain symptomatic despite maximal medical therapy. Gene therapy offers an attractive alternative to current pharmacologic therapies and may be beneficial in refractory disease. Gene therapy with isoforms of growth factors such as VEGF, FGF and HGF induces angiogenesis, decreases apoptosis and leads to protection in the ischemic heart. Stem cell therapy augmented with gene therapy used for myogenesis has proven to be beneficial in numerous animal models of myocardial ischemia. Gene therapy coding for antioxidants, eNOS, HSP, mitogen-activated protein kinase and numerous other anti apoptotic proteins have demonstrated significant cardioprotection in animal models. Clinical trials have demonstrated safety in humans apart from symptomatic and objective improvements in cardiac function. Current research efforts are aimed at refining various gene transfection techniques and regulation of gene expression in vivo in the heart and circulation to improve clinical outcomes in patients that suffer from ischemic heart disease. In this review article we will attempt to summarize the current state of both preclinical and clinical studies of gene therapy to combat myocardial ischemic disease. PMID:20600100

  20. Mobilization of Endogenous Bone Marrow Derived Endothelial Progenitor Cells and Therapeutic Potential of Parathyroid Hormone after Ischemic Stroke in Mice

    PubMed Central

    Wang, Li-Li; Chen, Dongdong; Lee, Jinhwan; Gu, Xiaohuan; Alaaeddine, Ghina; Li, Jimei; Wei, Ling; Yu, Shan Ping

    2014-01-01

    Stroke is a major neurovascular disorder threatening human life and health. Very limited clinical treatments are currently available for stroke patients. Stem cell transplantation has shown promising potential as a regenerative treatment after ischemic stroke. The present investigation explores a new concept of mobilizing endogenous stem cells/progenitor cells from the bone marrow using a parathyroid hormone (PTH) therapy after ischemic stroke in adult mice. PTH 1-34 (80 µg/kg, i.p.) was administered 1 hour after focal ischemia and then daily for 6 consecutive days. After 6 days of PTH treatment, there was a significant increase in bone marrow derived CD-34/Fetal liver kinase-1 (Flk-1) positive endothelial progenitor cells (EPCs) in the peripheral blood. PTH treatment significantly increased the expression of trophic/regenerative factors including VEGF, SDF-1, BDNF and Tie-1 in the brain peri-infarct region. Angiogenesis, assessed by co-labeled Glut-1 and BrdU vessels, was significantly increased in PTH-treated ischemic brain compared to vehicle controls. PTH treatment also promoted neuroblast migration from the subventricular zone (SVZ) and increased the number of newly formed neurons in the peri-infarct cortex. PTH-treated mice showed significantly better sensorimotor functional recovery compared to stroke controls. Our data suggests that PTH therapy improves endogenous repair mechanisms after ischemic stroke with functional benefits. Mobilizing endogenous bone marrow-derived stem cells/progenitor cells using PTH and other mobilizers appears an effective and feasible regenerative treatment after ischemic stroke. PMID:24503654

  1. 40 CFR 85.2220 - Preconditioned two speed idle test-EPA 91.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Preconditioned two speed idle test-EPA 91. 85.2220 Section 85.2220...Emission Control System Performance Warranty Short Tests § 85.2220 Preconditioned two speed idle test—EPA 91. (a) General requirements...

  2. 40 CFR 85.2220 - Preconditioned two speed idle test-EPA 91.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Preconditioned two speed idle test-EPA 91. 85.2220 Section 85.2220...Emission Control System Performance Warranty Short Tests § 85.2220 Preconditioned two speed idle test—EPA 91. (a) General requirements...

  3. 40 CFR 85.2220 - Preconditioned two speed idle test-EPA 91.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false Preconditioned two speed idle test-EPA 91. 85.2220 Section 85.2220...Emission Control System Performance Warranty Short Tests § 85.2220 Preconditioned two speed idle test—EPA 91. (a) General requirements...

  4. 40 CFR 85.2220 - Preconditioned two speed idle test-EPA 91.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Preconditioned two speed idle test-EPA 91. 85.2220 Section 85.2220...Emission Control System Performance Warranty Short Tests § 85.2220 Preconditioned two speed idle test—EPA 91. (a) General requirements...

  5. 40 CFR 1065.590 - PM sampling media (e.g., filters) preconditioning and tare weighing.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 2012-07-01 false PM sampling media (e.g., filters) preconditioning and...Duty Cycles § 1065.590 PM sampling media (e.g., filters) preconditioning and...the following steps to prepare PM sampling media (e.g., filters) and equipment...

  6. 40 CFR 1065.590 - PM sampling media (e.g., filters) preconditioning and tare weighing.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 2011-07-01 false PM sampling media (e.g., filters) preconditioning and...Duty Cycles § 1065.590 PM sampling media (e.g., filters) preconditioning and...the following steps to prepare PM sampling media (e.g., filters) and equipment...

  7. 40 CFR 1065.590 - PM sampling media (e.g., filters) preconditioning and tare weighing.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 2013-07-01 false PM sampling media (e.g., filters) preconditioning and...Duty Cycles § 1065.590 PM sampling media (e.g., filters) preconditioning and...the following steps to prepare PM sampling media (e.g., filters) and equipment...

  8. 40 CFR 1065.590 - PM sampling media (e.g., filters) preconditioning and tare weighing.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 2014-07-01 false PM sampling media (e.g., filters) preconditioning and...Duty Cycles § 1065.590 PM sampling media (e.g., filters) preconditioning and...the following steps to prepare PM sampling media (e.g., filters) and equipment...

  9. 40 CFR 85.2220 - Preconditioned two speed idle test-EPA 91.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Preconditioned two speed idle test-EPA... Warranty Short Tests § 85.2220 Preconditioned two speed idle test—EPA 91. (a) General requirements—(1...-speed mode followed immediately by a first-chance idle mode. (ii) The second-chance test as...

  10. Waveform Preconditioning for Clutter Rejection in Multipath for Sparse Distributed Apertures

    E-print Network

    Yazici, Birsen

    Waveform Preconditioning for Clutter Rejection in Multipath for Sparse Distributed Apertures T preconditioning, distributed aperture, sparse aperture, waveform design, imaging. 1. INTRODUCTION In this paper we transmission. The work applies to systems with an arbitrary number of transmit- and receive-antenna elements

  11. Sensory Preconditioning in Newborn Rabbits: From Common to Distinct Odor Memories

    ERIC Educational Resources Information Center

    Coureaud, Gerard; Tourat, Audrey; Ferreira, Guillaume

    2013-01-01

    This study evaluated whether olfactory preconditioning is functional in newborn rabbits and based on joined or independent memory of odorants. First, after exposure to odorants A+B, the conditioning of A led to high responsiveness to odorant B. Second, responsiveness to B persisted after amnesia of A. Third, preconditioning was also functional…

  12. Sound preconditioning therapy inhibits ototoxic hearing loss in mice.

    PubMed

    Roy, Soumen; Ryals, Matthew M; Van den Bruele, Astrid Botty; Fitzgerald, Tracy S; Cunningham, Lisa L

    2013-11-01

    Therapeutic drugs with ototoxic side effects cause significant hearing loss for thousands of patients annually. Two major classes of ototoxic drugs are cisplatin and the aminoglycoside antibiotics, both of which are toxic to mechanosensory hair cells, the receptor cells of the inner ear. A critical need exists for therapies that protect the inner ear without inhibiting the therapeutic efficacy of these drugs. The induction of heat shock proteins (HSPs) inhibits both aminoglycoside- and cisplatin-induced hair cell death and hearing loss. We hypothesized that exposure to sound that is titrated to stress the inner ear without causing permanent damage would induce HSPs in the cochlea and inhibit ototoxic drug–induced hearing loss. We developed a sound exposure protocol that induces HSPs without causing permanent hearing loss. We used this protocol in conjunction with a newly developed mouse model of cisplatin ototoxicity and found that preconditioning mouse inner ears with sound has a robust protective effect against cisplatin-induced hearing loss and hair cell death. Sound therapy also provided protection against aminoglycoside-induced hearing loss. These data indicate that sound preconditioning protects against both classes of ototoxic drugs, and they suggest that sound therapy holds promise for preventing hearing loss in patients receiving these drugs. PMID:24216513

  13. AIF depletion provides neuroprotection through a preconditioning effect.

    PubMed

    Öxler, Eva-Maria; Dolga, Amalia; Culmsee, C

    2012-10-01

    Previous studies established a major role for apoptosis inducing factor (AIF) in neuronal cell death after acute brain injury. For example, AIF translocation from mitochondria to the nucleus determined delayed neuronal death, whereas reduced AIF expression provided neuroprotective effects in models of cerebral ischemia or brain trauma. The question remains, however, why reduced AIF levels are sufficient to mediate neuroprotection, since only very little AIF translocation to the nucleus is required for induction of cell death. Thus, the present study addresses the question, whether AIF gene silencing affects intrinsic death pathways upstream of nuclear translocation at the level of the mitochondria. Using MTT assays and real-time cell impedance measurements we confirmed the protective effect of AIF siRNA against glutamate toxicity in immortalized mouse hippocampal HT-22 neurons. Further, AIF siRNA prevented glutamate-induced mitochondrial fragmentation and loss of mitochondrial membrane potential. The protection of mitochondrial integrity was associated with preserved ATP levels, attenuated increases in lipid peroxidation and reduced complex I expression levels. Notably, low concentrations of the complex I inhibitor rotenone (20 nM), provided similar protective effects against glutamate toxicity at the mitochondrial level. These results expose a preconditioning effect as a mechanism for neuroprotection mediated by AIF depletion. In particular, they point out an association between mitochondrial complex I and AIF, which regulate each other's stability in mitochondria. Overall, these findings postulate that AIF depletion mediates a preconditioning effect protecting neuronal cells from subsequent glutamate toxicity through reduced levels of complex I protein. PMID:22865232

  14. IPS guidestar selection for stellar mode (ASTRO)

    NASA Technical Reports Server (NTRS)

    Mullins, Larry; Wooten, Lewis

    1988-01-01

    This report describes how guide stars are selected for the Optical Sensor Package (OSP) for the Instrument Pointing System (IPS) when it is operating in the stellar mode on the ASTRO missions. It also describes how the objective loads are written and how the various roll angles are related; i.e., the celestial roll or position angle, the objective load roll angles, and the IPS gimbal angles. There is a brief description of how the IPS operates and its various modes of operation; i.e., IDOP, IDIN, and OSPCAL.

  15. Scalable architecture for VoIP privacy

    NASA Astrophysics Data System (ADS)

    Medvinsky, Alexander

    2001-07-01

    An access network for Voice over IP (VoIP) clients (e.g. DOCSIS-based HFC network) often provides a privacy service. However, such a privacy service is limited only to that access network. When VoIP packets are carried over an open IP network or over a network with some connections to the Internet, it is desirable to provide an end-to-end privacy service where each VoIP packet is encrypted at the source and decrypted at the terminating endpoint. Clearly, public key encryption cannot be applied to each voice packet; the performance would be unacceptable regardless of the choice of a public key algorithm. The only alternative is for the two VoIP endpoints to negotiate a shared symmetric key. Since VoIP connections are established only for duration of a phone call, the end-to-end key negotiation needs to occur during each call setup. And it should not noticeably delay the call setup phase. In order to provide end-to-end privacy, it is not sufficient to encrypt all messages between the two endpoints. It is important that the two endpoints authenticate each other - validate each other's identity. Without authentication an adversary might trick two VoIP clients to negotiate keys with her and then sit in the middle of their conversation and record each VoIP packet, before forwarding it to the intended destination. However, direct authentication of the two VoIP endpoints is not always possible in telephony networks - in particular when caller ID blocking services are enabled. To support such anonymity services, it may be sufficient to authenticate not the identity of the caller but the fact that it is a valid subscriber and that all subsequent signaling and voice traffic will be coming from the same source. The PacketCable specifications provide an example of a VoIP architecture with end-to-end privacy that meets the above stated criteria. This paper describes the PacketCable end-to-end privacy approach and suggests additional mechanisms that may be used to further strengthen VoIP privacy under the PacketCable architecture.

  16. Low diffusion E-CUSP scheme with high order WENO scheme for preconditioned Navier-Stokes equations

    E-print Network

    Zha, Gecheng

    Low diffusion E-CUSP scheme with high order WENO scheme for preconditioned Navier-Stokes equations-Seidel relaxation scheme for time integration, the LDE scheme with high-order WENO reconstruction is used is to develop a preconditioned low diffusion E-CUSP scheme with high order WENO scheme for preconditioned Navier

  17. pGlu-serpinin protects the normotensive and hypertensive heart from ischemic injury.

    PubMed

    Pasqua, T; Tota, B; Penna, C; Corti, A; Cerra, M C; Loh, Y P; Angelone, T

    2015-12-01

    Serpinin peptides derive from proteolytic cleavage of Chromogranin-A at C-terminus. Serpinin and the more potent pyroglutaminated-serpinin (pGlu-Serp) are positive cardiac ?-adrenergic-like modulators, acting through ?1-AR/AC/cAMP/PKA pathway. Because in some conditions this pathway and/or other pro-survival pathways, activated by other Chromogranin-A fragments, may cross-talk and may be protective, here we explored whether pGlu-Serp cardioprotects against ischemia/reperfusion injury under normotensive and hypertensive conditions. In the latter condition, cardioprotection is often blunted because of the limitations on pro-survival Reperfusion Injury Salvage Kinases (RISK) pathway activation. The effects of pGlu-Serp were evaluated on infarct size (IS) and cardiac function by using the isolated and Langendorff perfused heart of normotensive (Wistar Kyoto, WKY) and spontaneously hypertensive (SHR) rats exposed to ischemic pre-conditioning (PreC) and post-conditioning (PostC). In both WKY and SHR rat, pGlu-Serp induced mild cardioprotection in both PreC and PostC. pGlu-Serp administered at the reperfusion (Serp-PostC) significantly reduced IS, being more protective in SHR than in WKY. Conversely, left ventricular developed pressure (LVDevP) post-ischemic recovery was greater in WKY than in SHR. pGlu-Serp-PostC reduced contracture in both strains. Co-infusion with specific RISK inhibitors (PI3K/Akt, MitoKATP channels and PKC) blocked the pGlu-Serp-PostC protective effects. To show direct effect on cardiomyocytes, we pre-treated H9c2 cells with pGlu-Serp, which were thus protected against hypoxia/reoxygenation. These results suggest pGlu-Serp as a potential modulatory agent implicated in the protective processes that can limit infarct size and overcome the hypertension-induced failure of PostC. PMID:26400960

  18. Involvement of alpha-calcitonin gene-related peptide in monophosphoryl lipid A-induced delayed preconditioning in rat hearts.

    PubMed

    Peng, Jun; Lu, Rong; Deng, Han Wu; Li, Yuan Jian

    2002-02-01

    Recent study has shown that monophosphoryl lipid A-induced delayed preconditioning enhanced preservation with cardioplegia and that the protective effects of monophosphoryl lipid A were related to stimulation of calcitonin gene-related peptide (CGRP) release. The purpose of the present study was to explore whether the elevated release of CGRP induced by monophosphoryl lipid A is secondary to stimulation of CGRP synthesis via the nitric oxide (NO) pathway and to characterize the isoform of CGRP. Sprague-Dawley rats were pretreated with monophosphoryl lipid A 24 h before the experiment, and then the left main coronary artery of rat hearts was subjected to 1 h occlusion followed by 3 h reperfusion. Infarct size, plasma creatine kinase activity, the plasma level of CGRP, and the expression of CGRP isoforms (alpha- and beta-CGRP) mRNA in lumbar dorsal root ganglia were measured. Pretreatment with monophosphoryl lipid A (500 microg/kg, i.p.) significantly reduced infarct size and creatine kinase release. Monophosphoryl lipid A caused a significant increase in the expression of alpha-CGRP mRNA, but not of beta-CGRP mRNA, concomitantly with an increase in plasma concentrations of CGRP, and the increased level of CGRP expression happened before stimulation of CGRP release. The effect of monophosphoryl lipid A was completely abolished by pretreatment with L-nitroarginine methyl ester (L-NAME, 10 mg/kg, i.p.), an inhibitor of NO synthase or capsaicin (50 mg/kg, s.c.), which selectively depletes transmitters in capsaicin-sensitive sensory nerves. The results suggest that the delayed cardioprotection afforded by monophosphoryl lipid A involves the synthesis and release of CGRP via the NO pathway, and that the protection is mainly mediated by the alpha-CGRP isoform. PMID:11834251

  19. In vivo detection of the effects of preconditioning on LNCaP tumors by a TNF-? nanoparticle construct using MRI.

    PubMed

    Iltis, Isabelle; Choi, Jeunghwan; Vollmers, Manda; Shenoi, Mithun; Bischof, John; Metzger, Gregory J

    2014-09-01

    The outcome of systemic and local therapies (e.g. chemotherapy, radiotherapy, surgery, focal ablation) for prostate cancer can be significantly improved by using tumor-specific adjuvants prior to treatment ("preconditioning"). We propose to use dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) to monitor the in vivo response of a mouse model of prostate cancer treated with a vascular disruptive agent, TNF-?, delivered on a gold nanoparticle (NP-TNF). Six male nude mice bearing 4-5 week old LNCaP tumors were scanned at 9.4 T. DCE-MRI was performed two days before and 4-5 h after treatment with NP-TNF. An intraperitoneal (i.p.) bolus of gadolinium-DTPA (Gd) was administered and contrast enhancement was measured for 90 min. Concentration-time curves of Gd were calculated and the area under the Gd curve (AUGC) was determined pre- and post-treatment. NP-TNF treatment caused an increase in contrast uptake in tumors. Interestingly, the early concentration (10 min post Gd bolus i.p.) was similar in both untreated and treated conditions; however, 90 min after injection, [Gd] was 3.4 times higher than before treatment. AUGC doubled from (11 ± 6) [Gd] × min before treatment to (22 ± 9) [Gd] × min after treatment. An increase in signal enhancement was also observed in the muscle but to a lesser degree. We also evaluated the kinetics of intravenous Gd administration in mice bearing a jugular vein catheter to mimic the delivery method used in clinical trials. The overall treatment effects were independent of the delivery pathway of the contrast agent. In conclusion, we show that DCE-MRI is suitable to detect changes associated with a vascular disruptive agent in a mouse model of prostate cancer. The ability to characterize the effects of nanoparticle therapy in vivo with non-destructive methods is important, as such compounds, in combination with treatment strategies, are progressing towards clinical trials. PMID:24980267

  20. Towards more power efficient IP lookup engines 

    E-print Network

    Ahmad, Seraj

    2007-04-25

    The IP lookup in internet routers requires implementation of the longest prefix match algorithm. The software or hardware implementations of routing trie based approaches require several memory accesses in order to perform ...

  1. De novo ChIP-seq analysis

    E-print Network

    He, Xin

    Methods for the analysis of chromatin immunoprecipitation sequencing (ChIP-seq) data start by aligning the short reads to a reference genome. While often successful, they are not appropriate for cases where a reference ...

  2. On the development of Voice over IP 

    E-print Network

    Yang, Xu

    2009-05-15

    Internet Protocol (VoIP) security and proposed an Internet draft on secure retargeting and response identity. The draft provides a simple and comprehensive solution to the response identity, call recipient identity and intermediate server retargeting...

  3. IP routing lookup: hardware and software approach 

    E-print Network

    Chakaravarthy, Ravikumar V.

    2005-08-29

    The work presented in this thesis is motivated by the dual goal of developing a scalable and efficient approach for IP lookup using both hardware and software approach. The work involved designing algorithms and techniques to increase the capacity...

  4. Protection of retinal function by sulforaphane following retinal ischemic injury.

    PubMed

    Ambrecht, Lindsay A; Perlman, Jay I; McDonnell, James F; Zhai, Yougang; Qiao, Liang; Bu, Ping

    2015-09-01

    Sulforaphane, a precursor of glucosinolate in cruciferous vegetables such as broccoli and cauliflower, has been shown to protect brain ischemic injury. In this study, we examined the effect of systemic administration of sulforaphane on retinal ischemic reperfusion injury. Intraocular pressure was elevated in two groups of C57BL/6 mice (n = 8 per group) for 45 min to induce retinal ischemic reperfusion injury. Following retinal ischemic reperfusion injury, vehicle (1% DMSO saline) or sulforaphane (25 mg/kg/day) was administered intraperitoneally daily for 5 days. Scotopic electroretinography (ERG) was used to quantify retinal function prior to and one-week after retinal ischemic insult. Retinal morphology was examined one week after ischemic insult. Following ischemic reperfusion injury, ERG a- and b-wave amplitudes were significantly reduced in the control mice. Sulforaphane treatment significantly attenuated ischemic-induced loss of retinal function as compared to vehicle treated mice. In vehicle treated mice, ischemic reperfusion injury produced marked thinning of the inner retinal layers, but the thinning of the inner retinal layers appeared significantly less with sulforaphane treatment. Thus, sulforaphane may be beneficial in the treatment of retinal disorders with ischemic reperfusion injury. PMID:26142954

  5. A mathematical model of ischemic cutaneous wounds

    PubMed Central

    Xue, Chuan; Friedman, Avner; Sen, Chandan K.

    2009-01-01

    Chronic wounds represent a major public health problem affecting 6.5 million people in the United States. Ischemia, primarily caused by peripheral artery diseases, represents a major complicating factor in cutaneous wound healing. In this work, we sought to develop a mathematical model of ischemic dermal wounds. The model consists of a coupled system of partial differential equations in the partially healed region, with the wound boundary as a free boundary. The extracellular matrix (ECM) is assumed to be viscoelastic, and the free boundary moves with the velocity of the ECM at the boundary. The model equations involve the concentration of oxygen, PDGF and VEGF, the densities of macrophages, fibroblasts, capillary tips and sprouts, and the density and velocity of the ECM. Simulations of the model demonstrate how ischemic conditions may limit macrophage recruitment to the wound-site and impair wound closure. The results are in general agreement with experimental findings. PMID:19805373

  6. Recent Advances in Childhood Arterial Ischemic Stroke

    PubMed Central

    Fullerton, Heather J.

    2010-01-01

    Although many underlying diseases have been reported in the setting of childhood arterial ischemic stroke, emerging research demonstrates that non-atherosclerotic intracerebral arteriopathies in otherwise healthy children are prevalent. Minor infections may play a role in arteriopathies that have no other apparent underlying cause. Although stroke in childhood differs in many aspects from adult stroke, few systematic studies specific to pediatrics are available to inform stroke management. Treatment trials of pediatric stroke are required to determine the best strategies for acute treatment and secondary stroke prevention. The high cost of pediatric stroke to children, families, and society demands further study of its risk factors, management, and outcomes. This review focuses on the recent findings in childhood arterial ischemic stroke. PMID:20473592

  7. Student IP Policy Findings and Recommendations of the

    E-print Network

    Frey, H. Christopher

    Student IP Policy Findings and Recommendations of the College of Engineering ad hoc IP Policy concerns raised by COE Executive Committee concerning IP produced by UG students in the pursuit and UNC IP policy Research the policies and practices of selected peers Membership Tom Miller, chair; Dick

  8. New Directions for FPGA IP Core Watermarking and Identification

    E-print Network

    Teich, Jürgen

    New Directions for FPGA IP Core Watermarking and Identification Daniel Ziener, J¨urgen Teich, we present an overview of new watermarking and identification techniques for FPGA IP cores. Unlike characteristics of the IP core, e.g., lookup table con- tents for FPGA IP cores. With these techniques, the author

  9. Hardware IP Protection during Evaluation Using Embedded Sequential Trojan

    E-print Network

    Bhunia, Swarup

    (IP) cores is an important step in an IP-based system-on-chip (SoC) design flow. From the perspective Property (IP) cores has become a pervasive practice in the industry to realize bug-free complex SoCs under aggressive time-to- market target [1]. These IP cores usually come in the form of synthesizable Register

  10. Increasing pipelined IP core utilization in Process Networks using Exploration

    E-print Network

    Kienhuis, Bart

    Increasing pipelined IP core utilization in Process Networks using Exploration Claudiu Zissulescu, using IP cores to imple- ment the data-path of the applications. A particular characteristic of IP cores in the final hardware implementation of a PN, espe- cially if the IP cores are deeply

  11. Antioxidant Enzyme Gene Transfer for Ischemic Diseases

    PubMed Central

    Wu, Jian; Hecker, James G.; Chiamvimonvat, Nipavan

    2009-01-01

    The balance of redox is pivotal for normal function and integrity of tissues. Ischemic insults occur as results of a variety of conditions, leading to an accumulation of reactive oxygen species (ROS) and an imbalanced redox status in the tissues. The oxidant stress may activate signaling mechanisms provoking more toxic events, and eventually cause tissue damage. Therefore, treatments with antioxidants, free radical scavengers and their mimetics, as well as gene transfer approaches to overexpress antioxidant genes represent potential therapeutic options to correct the redox imbalance. Among them, antioxidant gene transfer may enhance the production of antioxidant scavengers, and has been employed to experimentally prevent or treat ischemic injury in cardiovascular, pulmonary, hepatic, intestinal, central nervous or other systems in animal models. With improvements in vector systems and delivery approaches, innovative antioxidant gene therapy has conferred better outcomes for myocardial infarction, reduced restenosis after coronary angioplasty, improved the quality and function of liver grafts, as well as outcome of intestinal and cerebral ischemic attacks. However, it is crucial to be mindful that like other therapeutic armentarium, the efficacy of antioxidant gene transfer requires extensive preclinical investigation before it can be used in patients, and that it may have unanticipated short- or long-term adverse effects. Thus, it is critical to balance between the therapeutic benefits and potential risks, to develop disease-specific antioxidant gene transfer strategies, to deliver the therapy with an optimal time window and in a safe manner. This review attempts to provide the rationale, the most effective approaches and the potential hurdles of available antioxidant gene transfer approaches for ischemic injury in various organs, as well as the possible directions of future preclinical and clinical investigations of this highly promising therapeutic modality. PMID:19233238

  12. Ischemic colitis in an endurance runner.

    PubMed

    Grames, Chase; Berry-Cabán, Cristóbal S

    2012-01-01

    A 20-year-old female running the Marine Corps Marathon developed diarrhea at mile 12. After finishing the race she noted that she was covered in bloody stool. A local emergency department suspected ischemic colitis. After discharge, her primary care physician instructed her to discontinue the use of all nonsteroidal anti-inflammatory drugs. Her symptoms resolved and she returned to running without any complications. This paper describes the pathophysiology, diagnostic approach, and management options. PMID:23091744

  13. The Effect of Hypoxic Preconditioning on Induced Schwann Cells under Hypoxic Conditions

    PubMed Central

    Chen, Ou; Wu, Miaomiao; Jiang, Liangfu

    2015-01-01

    Object Our objective was to explore the protective effects of hypoxic preconditioning on induced Schwann cells exposed to an environment with low concentrations of oxygen. It has been observed that hypoxic preconditioning of induced Schwann cells can promote axonal regeneration under low oxygen conditions. Method Rat bone marrow mesenchymal stem cells (MSCs) were differentiated into Schwann cells and divided into a normal oxygen control group, a hypoxia-preconditioning group and a hypoxia group. The ultrastructure of each of these groups of cells was observed by electron microscopy. In addition, flow cytometry was used to measure changes in mitochondrial membrane potential. Annexin V-FITC/PI staining was used to detect apoptosis, and Western blots were used to detect the expression of Bcl-2/Bax. Fluorescence microscopic observations of axonal growth in NG-108 cells under hypoxic conditions were also performed. Results The hypoxia-preconditioning group maintained mitochondrial cell membrane and crista integrity, and these cells exhibited less edema than the hypoxia group. In addition, the cells in the hypoxia-preconditioning group were found to be in early stages of apoptosis, whereas cells from the hypoxia group were in the later stages of apoptosis. The hypoxia-preconditioning group also had higher levels of Bcl-2/Bax expression and longer NG-108 cell axons than were observed in the hypoxia group. Conclusion Hypoxic preconditioning can improve the physiological state of Schwann cells in a severe hypoxia environment and improve the ability to promote neurite outgrowth. PMID:26509259

  14. [Ischemic stroke in the young adult].

    PubMed

    Calvet, D

    2016-01-01

    Ischemic stroke is not rare in young adults since one in ten stroke patients are less than 50years old. This incidence increased over the past last years, mainly due to the rise in the prevalence of traditional vascular risk factors in this sub-group of age but also of illegal drug use. Even though both survival and functional outcome of young stroke patients are better than those observed in older patients, socio-economic and quality of life consequences make this disease a main objective in terms of primary and secondary prevention. Identifying the cause of ischemic stroke in young adults is of major importance to prevent stroke recurrence. However, given the wide variety of potential underlying causes, the etiologic work-up of stroke in young adults requires a different approach from that in the elderly. In this context, a sequential diagnostic work-up is needed in order to optimize the yield of diagnostic tests, to reduce their cost and risks for the patient. Arterial dissection is the most frequent cause of stroke in young adults but other less frequent causes are numerous. Despite a comprehensive work-up, about one third of cases remains unexplained leading to the diagnosis of cryptogenic ischemic stroke. PMID:26361979

  15. The goldilocks dilemma in acute ischemic stroke.

    PubMed

    Tansy, Aaron P; Liebeskind, David S

    2013-01-01

    Despite the advent of and exciting advances in novel endovascular therapies, t-PA remains the only proven treatment for acute ischemic stroke to date. Although a variety of reasons likely underlie why past trials of endovascular strategies have been unsuccessful, we address in this perspective piece one critical unknown for which a solution is undoubtedly necessary if future ones are to meet with success: determination and selection of patients that are "just right" for endovascular treatments, or the Goldilocks dilemma. Key clinical criteria highlighted in past trials may help provide a solution to this critical problem. However, for them to do so, we propose that they must be applied in service of a model that accounts for the nuanced, dynamic nature of acute ischemic stroke better than the prevailing "time is brain" model. We provide and examine three clinical cases to illustrate this proposal towards solving the Goldilocks dilemma and advancing treatment in acute ischemic stroke. Further, we address our field's ongoing challenge and mission in the meantime to best care for the "not-so-right" patients, by far the majority of the affected stroke population. PMID:24155740

  16. Neurovascular remodeling in the aged ischemic brain.

    PubMed

    Hermann, Dirk M; Buga, Ana-Maria; Popa-Wagner, Aurel

    2015-08-01

    Restorative strategies after stroke are focused on the remodeling of cerebral endothelial cells and brain parenchymal cells. The latter, i.e., neurons, neural precursor cells and glial cells, synergistically interact with endothelial cells in the ischemic brain, providing a neurovascular unit whose components can be used as target for stroke therapies. Following focal cerebral ischemia, brain capillary cells are enabled to sprout. Neural precursor cells proliferate and migrate along cerebral microvessels to the ischemic lesion. Glial cells promote the restoration of functional microvessels and at the same time control the buildup of the extracellular matrix, creating a favorable environment to neuronal plasticity both in the ischemic and contralesional brain hemiphere. Until now, a large majority of studies have been performed in young, otherwise healthy animals. Recent behavioral, histochemical and molecular biological studies have shown that restorative brain responses differ between young and old animals, and that they are also modulated by age-related vascular risk factors, i.e., atherosclerosis, diabetes and hyperlipidemia. We claim that age aspects should more carefully be taken into consideration in translational proof-of-concept studies. PMID:24378703

  17. The sulfated polysaccharide fucoidan rescues senescence of endothelial colony-forming cells for ischemic repair.

    PubMed

    Lee, Jun Hee; Lee, Sang Hun; Choi, Sung Hyun; Asahara, Takayuki; Kwon, Sang-Mo

    2015-06-01

    The efficacy of cell therapy using endothelial colony-forming cells (ECFCs) in the treatment of ischemia is limited by the replicative senescence of isolated ECFCs in vitro. Such senescence must therefore be overcome in order for such cell therapies to be clinically applicable. This study aimed to investigate the potential of sulfated polysaccharide fucoidan to rescue ECFCs from cellular senescence and to improve in vivo vascular repair by ECFCs. Fucoidan-preconditioning of senescent ECFCs was shown by flow cytometry to restore the expression of functional ECFC surface markers (CD34, c-Kit, VEGFR2, and CXCR4) and stimulate the in vitro tube formation capacity of ECFCs. Fucoidan also promoted the expression of cell cycle-associated proteins (cyclin E, Cdk2, cyclin D1, and Cdk4) in senescent ECFCs, significantly reversed cellular senescence, and increased the proliferation of ECFCs via the FAK, Akt, and ERK signaling pathways. Fucoidan was found to enhance the survival, proliferation, incorporation, and endothelial differentiation of senescent ECFCs transplanted in ischemic tissues in a murine hind limb ischemia model. Moreover, ECFC-induced functional recovery and limb salvage were markedly improved by fucoidan pretreatment of ECFCs. To our knowledge, the findings of our study are the first to demonstrate that fucoidan enhances the neovasculogenic potential of ECFCs by rescuing them from replicative cellular senescence. Pretreatment of ECFCs with fucoidan may thus provide a novel strategy for the application of senescent stem cells to therapeutic neovascularization. PMID:25693733

  18. A frequency dependent preconditioned wavelet method for atmospheric tomography

    NASA Astrophysics Data System (ADS)

    Yudytskiy, Mykhaylo; Helin, Tapio; Ramlau, Ronny

    2013-12-01

    Atmospheric tomography, i.e. the reconstruction of the turbulence in the atmosphere, is a main task for the adaptive optics systems of the next generation telescopes. For extremely large telescopes, such as the European Extremely Large Telescope, this problem becomes overly complex and an efficient algorithm is needed to reduce numerical costs. Recently, a conjugate gradient method based on wavelet parametrization of turbulence layers was introduced [5]. An iterative algorithm can only be numerically efficient when the number of iterations required for a sufficient reconstruction is low. A way to achieve this is to design an efficient preconditioner. In this paper we propose a new frequency-dependent preconditioner for the wavelet method. In the context of a multi conjugate adaptive optics (MCAO) system simulated on the official end-to-end simulation tool OCTOPUS of the European Southern Observatory we demonstrate robustness and speed of the preconditioned algorithm. We show that three iterations are sufficient for a good reconstruction.

  19. Entanglement as precondition for secure quantum key distribution

    E-print Network

    Marcos Curty; Maciej Lewenstein; Norbert Lütkenhaus

    2003-07-21

    We demonstrate that a necessary precondition for unconditionally secure quantum key distribution is that sender and receiver can use the available measurement results to prove the presence of entanglement in a quantum state that is effectively distributed between them. One can thus systematically search for entanglement using the class of entanglement witness operators that can be constructed from the observed data. We apply such analysis to two well-known quantum key distribution protocols, namely the 4-state protocol and the 6-state protocol. As a special case, we show that, for some asymmetric error patterns, the presence of entanglement can be proven even for error rates above 25% (4-state protocol) and 33% (6-state protocol).

  20. Two New Gradient Precondition Schemes for Full Waveform Inversion

    E-print Network

    Huang, Guanghui; Ren, Haoran

    2014-01-01

    We propose two preconditioned gradient direction for full waveform inversion (FWI). The first one is using time integral wavefields. The Least square problem is formulated as the time integral residual wavefields, which can partially resolve the effect of high-passed filter in the traditional gradient formula; the convergence rate is greatly accelerated. The other one is localized offset Hessian inspired by the generalized imaging condition, which provides another redundancy in the Hessian. We compare the traditional conjugate gradient scaled by the shot illumination and localized offset Hessian (actually, only diagonal part is considered here), and contrast their performance for waveform inversion. The results demonstrate the localized offset Hessian (diagonal part) can provide much more information in the subsurface, and is preferred to the layer-strip inversion.

  1. Preconditioned Mixed Spectral Element Methods for Elasticity and Stokes Problems

    NASA Technical Reports Server (NTRS)

    Pavarino, Luca F.

    1996-01-01

    Preconditioned iterative methods for the indefinite systems obtained by discretizing the linear elasticity and Stokes problems with mixed spectral elements in three dimensions are introduced and analyzed. The resulting stiffness matrices have the structure of saddle point problems with a penalty term, which is associated with the Poisson ratio for elasticity problems or with stabilization techniques for Stokes problems. The main results of this paper show that the convergence rate of the resulting algorithms is independent of the penalty parameter, the number of spectral elements Nu and mildly dependent on the spectral degree eta via the inf-sup constant. The preconditioners proposed for the whole indefinite system are block-diagonal and block-triangular. Numerical experiments presented in the final section show that these algorithms are a practical and efficient strategy for the iterative solution of the indefinite problems arising from mixed spectral element discretizations of elliptic systems.

  2. Exercise and Cyclic Light Preconditioning Protect Against Light-Induced Retinal Degeneration and Evoke Similar Gene Expression Patterns.

    PubMed

    Chrenek, Micah A; Sellers, Jana T; Lawson, Eric C; Cunha, Priscila P; Johnson, Jessica L; Girardot, Preston E; Kendall, Cristina; Han, Moon K; Hanif, Adam; Ciavatta, Vincent T; Gogniat, Marissa A; Nickerson, John M; Pardue, Machelle T; Boatright, Jeffrey H

    2016-01-01

    To compare patterns of gene expression following preconditioning cyclic light rearing versus preconditioning aerobic exercise. BALB/C mice were preconditioned either by rearing in 800 lx 12:12 h cyclic light for 8 days or by running on treadmills for 9 days, exposed to toxic levels of light to cause light-induced retinal degeneration (LIRD), then sacrificed and retinal tissue harvested. Subsets of mice were maintained for an additional 2 weeks and for assessment of retinal function by electroretinogram (ERG). Both preconditioning protocols partially but significantly preserved retinal function and morphology and induced similar leukemia inhibitory factor (LIF) gene expression pattern. The data demonstrate that exercise preconditioning and cyclic light preconditioning protect photoreceptors against LIRD and evoke a similar pattern of retinal LIF gene expression. It may be that similar stress response pathways mediate the protection provided by the two preconditioning modalities. PMID:26427444

  3. A Novel Therapy to Attenuate Acute Kidney Injury and Ischemic Allograft Damage after Allogenic Kidney Transplantation in Mice

    PubMed Central

    Gueler, Faikah; Shushakova, Nelli; Mengel, Michael; Hueper, Katja; Chen, Rongjun; Liu, Xiaokun; Park, Joon-Keun; Haller, Hermann

    2015-01-01

    Ischemia followed by reperfusion contributes to the initial damage to allografts after kidney transplantation (ktx). In this study we tested the hypothesis that a tetrapeptide EA-230 (AQGV), might improve survival and attenuate loss of kidney function in a mouse model of renal ischemia/reperfusion injury (IRI) and ischemia-induced delayed graft function after allogenic kidney transplantation. IRI was induced in male C57Bl/6N mice by transient bilateral renal pedicle clamping for 35 min. Treatment with EA-230 (20–50mg/kg twice daily i.p. for four consecutive days) was initiated 24 hours after IRI when acute kidney injury (AKI) was already established. The treatment resulted in markedly improved survival in a dose dependent manner. Acute tubular injury two days after IRI was diminished and tubular epithelial cell proliferation was significantly enhanced by EA-230 treatment. Furthermore, CTGF up-regulation, a marker of post-ischemic fibrosis, at four weeks after IRI was significantly less in EA-230 treated renal tissue. To learn more about these effects, we measured renal blood flow (RBF) and glomerular filtration rate (GFR) at 28 hours after IRI. EA-230 improved both GFR and RBF significantly. Next, EA-230 treatment was tested in a model of ischemia-induced delayed graft function after allogenic kidney transplantation. The recipients were treated with EA-230 (50 mg/kg) twice daily i.p. which improved renal function and allograft survival by attenuating ischemic allograft damage. In conclusion, EA-230 is a novel and promising therapeutic agent for treating acute kidney injury and preventing IRI-induced post-transplant ischemic allograft injury. Its beneficial effect is associated with improved renal perfusion after IRI and enhanced regeneration of tubular epithelial cells. PMID:25617900

  4. 76 FR 81955 - Assessment Questionnaire-IP Sector Specific Agency Risk Self Assessment Tool (IP-SSARSAT)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-29

    ... From the Federal Register Online via the Government Printing Office DEPARTMENT OF HOMELAND SECURITY Assessment Questionnaire--IP Sector Specific Agency Risk Self Assessment Tool (IP-SSARSAT) AGENCY...: Assessment Questionnaire--IP Sector Specific Agency Risk Self Assessment Tool (IP-SSARSAT). OMB Number:...

  5. Eigenmode Analysis of Boundary Conditions for One-Dimensional Preconditioned Euler Equations

    NASA Technical Reports Server (NTRS)

    Darmofal, David L.

    1998-01-01

    An analysis of the effect of local preconditioning on boundary conditions for the subsonic, one-dimensional Euler equations is presented. Decay rates for the eigenmodes of the initial boundary value problem are determined for different boundary conditions. Riemann invariant boundary conditions based on the unpreconditioned Euler equations are shown to be reflective with preconditioning, and, at low Mach numbers, disturbances do not decay. Other boundary conditions are investigated which are non-reflective with preconditioning and numerical results are presented confirming the analysis.

  6. Mouse-induced pluripotent stem cells generated under hypoxic conditions in the absence of viral infection and oncogenic factors and used for ischemic stroke therapy.

    PubMed

    Liu, Shih-Ping; Fu, Ru-Huei; Wu, Dong-Chuan; Hsu, Chien-Yu; Chang, Cheng-Hsuan; Lee, Wei; Lee, Yu-Da; Liu, Chia Hui; Chien, Ying-Jiun; Lin, Shinn-Zong; Shyu, Woei-Cherng

    2014-02-15

    Induced pluripotent stem (iPS) cells are considered as having the greatest potential for use in cell-based therapies. However, at least two hurdles remain: integrating viral transgenes and introducing the c-Myc and Klf4 oncogenes. In a previous study, fibroblasts were incapable of generating iPS cells in the absence of both oncogenes and viral infection. For the present study, we tested our hypothesis that iPS cells can be generated without oncogenes and viral infection under hypoxic conditions and used for cell therapies. By avoiding oncogenic factors and virus integration, this strategy would decrease the potential for cancer formation. According to our observations, the repeated transfection of two expression plasmids (Oct4 and Sox2) into mouse embryonic fibroblasts (MEFs) and combined hypoxic condition resulted in the generation of a novel iPS cell. At 6 h post-transfection, MEFs were subjected to hypoxic conditions (3% O2) for 24 h; this procedure was repeated four times. The resulting MEFs were seeded on feeder cells on day 9; iPS cell clones were observed 12 days post-seeding and designated as iPS-OSH. Data for cell morphology, stem cell marker staining, gene expression profiles, and embryonic body, teratoma, and chimeric mouse formation indicated iPS-OSH pluripotent capability. Neural precursor cells differentiated from iPS-OSH cells were used to treat an ischemic stroke mouse model; results from a behavior analysis indicate that the therapeutic group surpassed the control group. Further, iPS-OSH-derived neural precursor cells differentiated into neurons and astrocytes in mouse stroke brains. In conclusion, we generated a novel iPS-OSH in the absence of viral infection and oncogenic factors and could use it for ischemic stroke therapy. PMID:24266622

  7. Regulation of IP 3 Receptors by IP 3 and Ca 2+

    NASA Astrophysics Data System (ADS)

    Taylor, Colin W.; Swatton, Jane E.

    Inositol 1,4,5-trisphosphate ( IP 3) receptors are intracellular Ca 2+ channels that mediate release of Ca 2+ from intracellular stores. The channels are oligomeric assemblies of four subunits, each of which has an N-terminal IP 3-binding domain and each of which contributes to formation of the Ca 2+ channel. In mammals, three different genes encode IP 3 receptors subunits and the type 1 receptor (and perhaps the type 2 receptor) is also expressed as splice variants. Further diversity arises from assembly of the receptor in hetero- and homo-tetrameric channels. The subtypes differ in their expression and regulation, but they share the key property of being regulated by both IP3 and cytosolic Ca 2+. All three mammalian IP 3 subtypes, and probably also the IP 3 receptors expressed in invertebrates, are biphasically regulated by cytosolic Ca2+, although the underlying mechanisms appear to differ between subtypes. The interactions between IP 3 and Ca 2+ in controlling IP 3 receptor gating, and the physiological significance of such regulation will be reviewed.

  8. Artificial muscle technology applied towards treating ischemic mitral regurgitation caused by left ventricular remodeling

    E-print Network

    Sabourin, Nicaulas A. (Nicaulas Alexandre), 1978-

    2004-01-01

    Ischemic Mitral Regurgitation (MR) affects a large portion of patients suffering from ischemic heart disease. Significant MR develops in one quarter to one third of patients who suffer from ischemic heart disease and doubles ...

  9. Abdominal Surgical Incision Induces Remote Preconditioning of Trauma (RPCT) via Activation of Bradykinin Receptors (BK2R) and the Cytochrome P450 Epoxygenase Pathway in Canine Hearts

    PubMed Central

    Gross, Garrett J.; Baker, John E.; Moore, Jeannine; Falck, John R.; Nithipatikom, Kasem

    2012-01-01

    Recently, a novel observation was made in which nonischemic trauma at a site remote from the heart produced by a transverse abdominal incision resulted in a marked reduction of infarct size (IS) in the mouse heart via activation of sensory nerve fibers in the skin and subsequent activation of bradykinin 2 receptors (BK2R). This phenomenon was termed remote preconditioning of trauma (RPCT). Since RPCT may have potential clinical implications we attempted to confirm these findings in a large animal model, the dog. The epoxyeicosatrienoic acids (EETs) have also recently been shown to be antinociceptive and have been shown to mimic ischemic preconditioning (IPC) and postconditioning (POC) in dogs, therefore, we tested the role of the EETs in RPCT. Anesthetized adult mongrel dogs of either sex were subjected to 60 min of left anterior descending (LAD) coronary artery occlusion followed by 3 h of reperfusion. In all groups except the controls (no slit), a transverse slit (9 cm) was applied to the abdominal wall of the dog being careful to only slit the skin. Subsequently, 15 min after the slit the heart was subjected to the ischemia/reperfusion protocol. In the control dogs, the IS as a percent of the area at risk (AAR) was 22.5 ± 2.4%, whereas in the dogs subjected to the slit alone the IS/AAR was reduced to 9.2 ± 1.2% (*P<0.01). The BR2R blocker, HOE 140 (50 ug/kg, iv) given 10 min prior to the slit, completely abolished the protective effects of RCPT as did pretreatment with 14,15-EEZE, a putative EET receptor blocker or pretreatment with the selective EET synthesis inhibitor, MSPPOH. These results suggest that BK and the EETs share cardioprotective properties in a large animal model of RPCT. PMID:21786213

  10. Analysis of a Lipid/Polymer Membrane for Bitterness Sensing with a Preconditioning Process.

    PubMed

    Yatabe, Rui; Noda, Junpei; Tahara, Yusuke; Naito, Yoshinobu; Ikezaki, Hidekazu; Toko, Kiyoshi

    2015-01-01

    It is possible to evaluate the taste of foods or medicines using a taste sensor. The taste sensor converts information on taste into an electrical signal using several lipid/polymer membranes. A lipid/polymer membrane for bitterness sensing can evaluate aftertaste after immersion in monosodium glutamate (MSG), which is called "preconditioning". However, we have not yet analyzed the change in the surface structure of the membrane as a result of preconditioning. Thus, we analyzed the change in the surface by performing contact angle and surface zeta potential measurements, Fourier transform infrared spectroscopy (FTIR), X-ray photon spectroscopy (XPS) and gas cluster ion beam time-of-flight secondary ion mass spectrometry (GCIB-TOF-SIMS). After preconditioning, the concentrations of MSG and tetradodecylammonium bromide (TDAB), contained in the lipid membrane were found to be higher in the surface region than in the bulk region. The effect of preconditioning was revealed by the above analysis methods. PMID:26404301

  11. Analysis of a Lipid/Polymer Membrane for Bitterness Sensing with a Preconditioning Process

    PubMed Central

    Yatabe, Rui; Noda, Junpei; Tahara, Yusuke; Naito, Yoshinobu; Ikezaki, Hidekazu; Toko, Kiyoshi

    2015-01-01

    It is possible to evaluate the taste of foods or medicines using a taste sensor. The taste sensor converts information on taste into an electrical signal using several lipid/polymer membranes. A lipid/polymer membrane for bitterness sensing can evaluate aftertaste after immersion in monosodium glutamate (MSG), which is called “preconditioning”. However, we have not yet analyzed the change in the surface structure of the membrane as a result of preconditioning. Thus, we analyzed the change in the surface by performing contact angle and surface zeta potential measurements, Fourier transform infrared spectroscopy (FTIR), X-ray photon spectroscopy (XPS) and gas cluster ion beam time-of-flight secondary ion mass spectrometry (GCIB-TOF-SIMS). After preconditioning, the concentrations of MSG and tetradodecylammonium bromide (TDAB), contained in the lipid membrane were found to be higher in the surface region than in the bulk region. The effect of preconditioning was revealed by the above analysis methods. PMID:26404301

  12. Hybrid preconditioning for iterative diagonalization of ill-conditioned generalized eigenvalue problems in electronic structure calculations

    SciTech Connect

    Cai, Yunfeng; Department of Computer Science, University of California, Davis 95616 ; Bai, Zhaojun; Pask, John E.; Sukumar, N.

    2013-12-15

    The iterative diagonalization of a sequence of large ill-conditioned generalized eigenvalue problems is a computational bottleneck in quantum mechanical methods employing a nonorthogonal basis for ab initio electronic structure calculations. We propose a hybrid preconditioning scheme to effectively combine global and locally accelerated preconditioners for rapid iterative diagonalization of such eigenvalue problems. In partition-of-unity finite-element (PUFE) pseudopotential density-functional calculations, employing a nonorthogonal basis, we show that the hybrid preconditioned block steepest descent method is a cost-effective eigensolver, outperforming current state-of-the-art global preconditioning schemes, and comparably efficient for the ill-conditioned generalized eigenvalue problems produced by PUFE as the locally optimal block preconditioned conjugate-gradient method for the well-conditioned standard eigenvalue problems produced by planewave methods.

  13. Preconditioning for Numerical Simulation of Low Mach Number Three-Dimensional Viscous Turbomachinery Flows

    NASA Technical Reports Server (NTRS)

    Tweedt, Daniel L.; Chima, Rodrick V.; Turkel, Eli

    1997-01-01

    A preconditioning scheme has been implemented into a three-dimensional viscous computational fluid dynamics code for turbomachine blade rows. The preconditioning allows the code, originally developed for simulating compressible flow fields, to be applied to nearly-incompressible, low Mach number flows. A brief description is given of the compressible Navier-Stokes equations for a rotating coordinate system, along with the preconditioning method employed. Details about the conservative formulation of artificial dissipation are provided, and different artificial dissipation schemes are discussed and compared. The preconditioned code was applied to a well-documented case involving the NASA large low-speed centrifugal compressor for which detailed experimental data are available for comparison. Performance and flow field data are compared for the near-design operating point of the compressor, with generally good agreement between computation and experiment. Further, significant differences between computational results for the different numerical implementations, revealing different levels of solution accuracy, are discussed.

  14. A survey of IP over ATM architectures

    SciTech Connect

    Chen, H.; Tsang, R.; Brandt, J.; Hutchins, J.

    1997-07-01

    Over the past decade, the Internet has burgeoned into a worldwide information highway consisting of approximately 5 million hosts on over 45,000 interconnected networks. This unprecedented growth, together with the introduction of multimedia workstations, has spurred the development of innovative applications that require high speed, low latency, and real-time transport. Today`s Internet can neither scale in its bandwidth nor guarantee the Quality of Services (QoS) necessary to meet these performance requirements. Many network researchers propose to use the Asynchronous Transfer Mode (ATM) technology as the underlying infrastructure for the next generation of workgroup, campus, and enterprise IP networks. Since ATM is significantly different from today`s legacy network technologies, efficient implementation of IP over ATM is especially challenging. This tutorial paper covers several existing proposals that integrate IP over ATM.

  15. Space-Based Voice over IP Networks

    NASA Technical Reports Server (NTRS)

    Nguyen, Sam P.; Okino, Clayton; Walsh, William; Clare, Loren

    2007-01-01

    In human space exploration missions (e.g. a return to the Moon and for future missions to Mars), there will be a need to provide voice communications services. In this work we focus on the performance of Voice over IP (VoIP) techniques applied to space networks, where long range latencies, simplex links, and significant bit error rates occur. Link layer and network layer overhead issues are examined. Finally, we provide some discussion on issues related to voice conferencing in the space network environment.

  16. Direct distance measurements to SN 2009ip

    NASA Astrophysics Data System (ADS)

    Potashov, M.; Blinnikov, S.; Baklanov, P.; Dolgov, A.

    2013-04-01

    We demonstrate the applicability of our new method (the Dense Shell Method or DSM) for the determination of astronomical distances by calculating the distance to SN 2009ip. The distance to this supernova has been accurately determined in the standard approach via the cosmic distance ladder and has been found to be 20.4 Mpc. Our direct method, assuming the most reasonable parameter values, gives a very close result, namely ?20.1 ± 0.8 (68 per cent CL) Mpc to SN 2009ip.

  17. De novo ChIP-seq analysis.

    PubMed

    He, Xin; Cicek, A Ercument; Wang, Yuhao; Schulz, Marcel H; Le, Hai-Son; Bar-Joseph, Ziv

    2015-01-01

    Methods for the analysis of chromatin immunoprecipitation sequencing (ChIP-seq) data start by aligning the short reads to a reference genome. While often successful, they are not appropriate for cases where a reference genome is not available. Here we develop methods for de novo analysis of ChIP-seq data. Our methods combine de novo assembly with statistical tests enabling motif discovery without the use of a reference genome. We validate the performance of our method using human and mouse data. Analysis of fly data indicates that our method outperforms alignment based methods that utilize closely related species. PMID:26400819

  18. Atorvastatin preconditioning improves the forward blood flow in the no-reflow rats.

    PubMed

    Shao, Liang; Zhang, Yong; Ma, Aiqun; Zhang, Ping; Wu, Dayin; Li, Wenzhu; Wang, Jue; Liu, Kun; Wang, Zhaohui

    2014-02-01

    Atorvastatin is not only an antilipemic but also used as an anti-inflammatory medicine in heart disease. Our working hypothesis was that atorvastatin preconditioning could improve the forward blood flow in the no-reflow rats associated with inflammation. We investigated that two doses of atorvastatin preconditioning (20 and 5 mg/kg/day) could alleviate deterioration of early cardiac diastolic function in rats with inflammation detected by echocardiography and haemodynamics. This benefit was obtained from the effect of atorvastatin preconditioning on improving forward blood flow and preserving the infarct cardiomyocytes, which was estimated by Thioflavin S and TTC staining in rats with myocardial ischemia/reperfusion. Subsequently, the improving of forward blood flow was ascribed to reduction of microthrombus in microvascular and myocardial fibrosis observed by MSB and Masson's trichrome staining with atorvastatin preconditioning. Ultimately, we found that atorvastatin preconditioning could reduce inflammation factor, such as tumor necrosis factor-? and fibrinogen-like protein 2, both in myocardial and in mononuclear cells, which probably attribute to microcirculation dysfunction in no-reflow rats detected by immunohistochemistry staining, western blot, and ELISA detection, respectively. In conclusion, atorvastatin preconditioning could alleviate deterioration of early cardiac diastolic function and improve the forward blood flow in the no-reflow rats attributing to reduction of TNF-? and fgl-2 expression. PMID:22985249

  19. Convergence Acceleration of the Navier-Stokes Equations Through Time-Derivative Preconditioning

    NASA Technical Reports Server (NTRS)

    Merkle, Charles L.; Venkateswaran, Sankaran; Deshpande, Manish

    1996-01-01

    Chorin's method of artificial compressibility is extended to both compressible and incompressible fluids by using physical arguments to define artificial fluid properties that make up a local preconditioning matrix. In particular, perturbation expansions are used to provide appropriate temporal derivatives for the equations of motion at both low speeds and low Reynolds numbers. These limiting forms are then combined into a single function that smoothly merges into the physical time derivatives at high speeds so that the equations are left unchanged at transonic, high Reynolds number conditions. The effectiveness of the resulting preconditioning procedures for the Navier-Stokes equations is demonstrated for a wide speed and Reynolds number ranges by means of stability results and computational solutions. Nevertheless, the preconditioned equations sometimes fail to provide a solution for applications for which the non-preconditioned equations converge. Often this is because the reduced dissipation in the preconditioned equations results in an unsteady solution while the more dissipative non-preconditioned equations result in a steady state. Problems of this type represent a computational challenge; it is important to distinguish between non-convergence of algorithms, and the non-existence of steady state solutions.

  20. Enhanced nucleotide excision repair capacity in lung cancer cells by preconditioning with DNA-damaging agents

    PubMed Central

    Choi, Ji Ye; Park, Jeong-Min; Yi, Joo Mi; Leem, Sun-Hee; Kang, Tae-Hong

    2015-01-01

    The capacity of tumor cells for nucleotide excision repair (NER) is a major determinant of the efficacy of and resistance to DNA-damaging chemotherapeutics, such as cisplatin. Here, we demonstrate that using lesion-specific monoclonal antibodies, NER capacity is enhanced in human lung cancer cells after preconditioning with DNA-damaging agents. Preconditioning of cells with a nonlethal dose of UV radiation facilitated the kinetics of subsequent cisplatin repair and vice versa. Dual-incision assay confirmed that the enhanced NER capacity was sustained for 2 days. Checkpoint activation by ATR kinase and expression of NER factors were not altered significantly by the preconditioning, whereas association of XPA, the rate-limiting factor in NER, with chromatin was accelerated. In preconditioned cells, SIRT1 expression was increased, and this resulted in a decrease in acetylated XPA. Inhibition of SIRT1 abrogated the preconditioning-induced predominant XPA binding to DNA lesions. Taking these data together, we conclude that upregulated NER capacity in preconditioned lung cancer cells is caused partly by an increased level of SIRT1, which modulates XPA sensitivity to DNA damage. This study provides some insights into the molecular mechanism of chemoresistance through acquisition of enhanced DNA repair capacity in cancer cells. PMID:26317794

  1. Effects of Thermal Preconditioning on Tissue Susceptibility to Histotripsy.

    PubMed

    Vlaisavljevich, Eli; Xu, Zhen; Arvidson, Alexa; Jin, Lifang; Roberts, William; Cain, Charles

    2015-11-01

    Histotripsy is a non-invasive ablation method that mechanically fractionates tissue by controlling acoustic cavitation. Previous work has revealed that tissue mechanical properties play a significant role in the histotripsy process, with stiffer tissues being more resistant to histotripsy-induced tissue damage. In this study, we propose a thermal pretreatment strategy to precondition tissues before histotripsy. We hypothesize that a thermal pretreatment can be used to alter tissue stiffness by modulating collagen composition, thus changing tissue susceptibility to histotripsy. More specifically, we hypothesize that tissues will soften and become more susceptible to histotripsy when preheated at ?60°C because of collagen denaturation, but that tissues will rapidly stiffen and become less susceptible to histotripsy when preheated at ?90°C because of collagen contraction. To test this hypothesis, a controlled temperature water bath was used to heat various ex vivo bovine tissues (tongue, artery, liver, kidney medulla, tendon and urethra). After heating, the Young's modulus of each tissue sample was measured using a tissue elastometer, and changes in tissue composition (i.e., collagen structure/density) were analyzed histologically. The susceptibility of tissues to histotripsy was investigated by treating the samples using a 750-kHz histotripsy transducer. Results revealed a decrease in stiffness and an increase in susceptibility to histotripsy for tissues (except urethra) preheated to 58°C. In contrast, preheating to 90°C increased tissue stiffness and reduced susceptibility to histotripsy for all tissues except tendon, which was significantly softened due to collagen hydrolysis into gelatin. On the basis of these results, a final set of experiments were conducted to determine the feasibility of using high-intensity focused ultrasound to provide the thermal pretreatment. Overall, the results of this study indicate the initial feasibility of a thermal pretreatment strategy to precondition tissue mechanical properties and alter tissue susceptibility to histotripsy. Future work will aim to optimize this thermal pretreatment strategy to determine if this approach is practical for specific clinical applications in vivo without causing unwanted damage to surrounding or overlying tissue. PMID:26318560

  2. Development of New IP Cores for Spacecraft Avionics

    NASA Astrophysics Data System (ADS)

    Isomaki, Marko; Ekergarn, Jonas; Hjorth, Magnus; Wessman, Nils-Johan; Habinc, Sandi

    2010-08-01

    The GRLIB IP library is an integrated set of reusable IP cores, designed for system-on-chip (SOC) development. The IP cores are centered around a common on-chip bus, and use a coherent method for simulation and synthesis. The library is vendor independent, with support for different CAD tools and target technologies. The success of any IP core library is highly dependent on the constantly increasing number of IP cores and the improvement of existing IP cores. This paper will cover both these aspects, presenting some new developments as well as some improvements of existing items.

  3. Changes of resting cerebral activities in subacute ischemic stroke patients

    PubMed Central

    Wu, Ping; Zeng, Fang; Li, Yong-xin; Yu, Bai-li; Qiu, Li-hua; Qin, Wei; Li, Ji; Zhou, Yu-mei; Liang, Fan-rong

    2015-01-01

    This study aimed to detect the difference in resting cerebral activities between ischemic stroke patients and healthy participants, define the abnormal site, and provide new evidence for pathological mechanisms, clinical diagnosis, prognosis prediction and efficacy evaluation of ischemic stroke. At present, the majority of functional magnetic resonance imaging studies focus on the motor dysfunction and the acute stage of ischemic stroke. This study recruited 15 right-handed ischemic stroke patients at subacute stage (15 days to 11.5 weeks) and 15 age-matched healthy participants. A resting-state functional magnetic resonance imaging scan was performed on each subject to detect cerebral activity. Regional homogeneity analysis was used to investigate the difference in cerebral activities between ischemic stroke patients and healthy participants. The results showed that the ischemic stroke patients had lower regional homogeneity in anterior cingulate and left cerebrum and higher regional homogeneity in cerebellum, left precuneus and left frontal lobe, compared with healthy participants. The experimental findings demonstrate that the areas in which regional homogeneity was different between ischemic stroke patients and healthy participants are in the cerebellum, left precuneus, left triangle inferior frontal gyrus, left inferior temporal gyrus and anterior cingulate. These locations, related to the motor, sensory and emotion areas, are likely potential targets for the neural regeneration of subacute ischemic stroke patients. PMID:26109950

  4. Operational Space Weather Products at IPS

    NASA Astrophysics Data System (ADS)

    Neudegg, D.; Steward, G.; Marshall, R.; Terkildsen, M.; Kennewell, J.; Patterson, G.; Panwar, R.

    2008-12-01

    IPS Radio and Space Services operates an extensive network (IPSNET) of monitoring stations and observatories within the Australasian and Antarctic regions to gather information on the space environment. This includes ionosondes, magnetometers, GPS-ISM, oblique HF sounding, riometers, and solar radio and optical telescopes. IPS exchanges this information with similar organisations world-wide. The Regional Warning Centre (RWC) is the Australian Space Forecast Centre (ASFC) and it utilizes this data to provide products and services to support customer operations. A wide range of customers use IPS services including; defence force and emergency services using HF radio communications and surveillance systems, organisations involved in geophysical exploration and pipeline cathodic protection, GPS users in aviation. Subscriptions to the alerts, warnings, forecasts and reports regarding the solar, geophysical and ionospheric conditions are distributed by email and Special Message Service (SMS). IPS also develops and markets widely used PC software prediction tools for HF radio skywave and surface wave (ASAPS/GWPS) and provides consultancy services for system planning.

  5. EQuIP-ped for Success

    ERIC Educational Resources Information Center

    Ewing, Molly

    2015-01-01

    The Educators Evaluating the Quality of Instructional Products (EQuIP) Rubric for science is a new tool for science educators that provides criteria by which to examine the alignment and overall quality of lessons and units with respect to the "Next Generation Science Standards" ("NGSS"). The rubric criteria are divided into…

  6. Is VoIP Worth It?

    ERIC Educational Resources Information Center

    Schaffhauser, Dian

    2008-01-01

    School districts have by and large had great results implementing VoIP, which has become the conduit for delivering expanded functionality, achieving greater internal control, and gaining freedom from onerous monthly phone bills. But demonstrating a financial return on what is a substantial investment can be an elusive effort. The goal of…

  7. Universal IP Multicast Delivery # Beichuan Zhang

    E-print Network

    California at Los Angeles, University of

    lowers the deployment barrier of multicast technology by moving multicast functionality from routers islands to achieve ubiquitous multicast delivery. We intend UM to be a general framework that can work ``islands.'' The design of UM takes full advantage of deployed IP multi­ cast where available and utilizes

  8. Universal IP Multicast Delivery Beichuan Zhang

    E-print Network

    Zhang, Beichuan

    lowers the deployment barrier of multicast technology by moving multicast functionality from routers islands to achieve ubiquitous multicast delivery. We intend UM to be a general framework that can work "islands." The design of UM takes full advantage of deployed IP multi- cast where available and utilizes

  9. How To: Be VoIP-Savvy

    ERIC Educational Resources Information Center

    Branzburg, Jeffrey

    2005-01-01

    Cablevision, Comcast, Verizon, and many other high-speed broadband Internet providers are now also offering telephone services through "Voice over Internet Protocol" (VoIP). This technology sends ordinary telephone calls over the Internet rather than over telephone lines. While impractical without the use of a broadband Internet connection, with…

  10. Call progress time measurement in IP telephony

    NASA Astrophysics Data System (ADS)

    Khasnabish, Bhumip

    1999-11-01

    Usually a voice call is established through multiple stages in IP telephony. In the first stage, a phone number is dialed to reach a near-end or call-originating IP-telephony gateway. The next stages involve user identification through delivering an m-digit user-id to the authentication and/or billing server, and then user authentication by using an n- digit PIN. After that, the caller is allowed (last stage dial tone is provided) to dial a destination phone number provided that authentication is successful. In this paper, we present a very flexible method for measuring call progress time in IP telephony. The proposed technique can be used to measure the system response time at every stage. It is flexible, so that it can be easily modified to include new `tone' or a set of tones, or `voice begin' can be used in every stage to detect the system's response. The proposed method has been implemented using scripts written in Hammer visual basic language for testing with a few commercially available IP telephony gateways.

  11. Cerenkov luminescence tomography based on preconditioning orthogonal matching pursuit

    NASA Astrophysics Data System (ADS)

    Liu, Haixiao; Hu, Zhenhua; Wang, Kun; Tian, Jie; Yang, Xin

    2015-03-01

    Cerenkov luminescence imaging (CLI) is a novel optical imaging method and has been proved to be a potential substitute of the traditional radionuclide imaging such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT). This imaging method inherits the high sensitivity of nuclear medicine and low cost of optical molecular imaging. To obtain the depth information of the radioactive isotope, Cerenkov luminescence tomography (CLT) is established and the 3D distribution of the isotope is reconstructed. However, because of the strong absorption and scatter, the reconstruction of the CLT sources is always converted to an ill-posed linear system which is hard to be solved. In this work, the sparse nature of the light source was taken into account and the preconditioning orthogonal matching pursuit (POMP) method was established to effectively reduce the ill-posedness and obtain better reconstruction accuracy. To prove the accuracy and speed of this algorithm, a heterogeneous numerical phantom experiment and an in vivo mouse experiment were conducted. Both the simulation result and the mouse experiment showed that our reconstruction method can provide more accurate reconstruction result compared with the traditional Tikhonov regularization method and the ordinary orthogonal matching pursuit (OMP) method. Our reconstruction method will provide technical support for the biological application for Cerenkov luminescence.

  12. Preconditioning Doses of NMDA Promote Neuroprotection by Enhancing Neuronal Excitability

    PubMed Central

    Soriano, Francesc X.; Papadia, Sofia; Hofmann, Frank; Hardingham, Neil R.; Bading, Hilmar; Hardingham, Giles E.

    2008-01-01

    Neuroprotection can be induced by low doses of NMDA, which activate both synaptic and extrasynaptic NMDA receptors. This is in apparent contradiction with our recent findings that extrasynaptic NMDA receptor signaling exerts a dominant inhibitory effect on prosurvival signaling from synaptic NMDA receptors. Here we report that exposure to low preconditioning doses of NMDA results in preferential activation of synaptic NMDA receptors because of a dramatic increase in action potential firing. Both acute and long-lasting phases of neuroprotection in the face of apoptotic or excitotoxic insults are dependent on this firing enhancement. Key mediators of synaptic NMDA receptor-dependent neuroprotection, phosphatidylinositol 3 kinase-Akt (PI3 kinase-Akt) signaling to Forkhead box subgroup O (FOXO) export and glycogen synthase kinase 3? (GSK3?) inhibition and cAMP response element-binding protein-dependent (CREB-dependent) activation of brain-derived neurotrophic factor (BDNF), can be induced only by low doses of NMDA via this action potential-dependent route. In contrast, NMDA doses on the other side of the toxicity threshold do not favor synaptic NMDA receptor activation because they strongly suppress firing rates below baseline. The classic bell-shaped curve depicting neuronal fate in response to NMDA dose can be viewed as the net effect of two antagonizing (synaptic vs extrasynaptic) curves: via increased firing the synaptic signaling dominates at low doses, whereas firing becomes suppressed and extrasynaptic signaling dominates as the toxicity threshold is crossed. PMID:16641230

  13. Meclizine Preconditioning Protects the Kidney Against Ischemia–Reperfusion Injury

    PubMed Central

    Kishi, Seiji; Campanholle, Gabriela; Gohil, Vishal M.; Perocchi, Fabiana; Brooks, Craig R.; Morizane, Ryuji; Sabbisetti, Venkata; Ichimura, Takaharu; Mootha, Vamsi K.; Bonventre, Joseph V.

    2015-01-01

    Global or local ischemia contributes to the pathogenesis of acute kidney injury (AKI). Currently there are no specific therapies to prevent AKI. Potentiation of glycolytic metabolism and attenuation of mitochondrial respiration may decrease cell injury and reduce reactive oxygen species generation from the mitochondria. Meclizine, an over-the-counter anti-nausea and -dizziness drug, was identified in a ‘nutrient-sensitized’ chemical screen. Pretreatment with 100 mg/kg of meclizine, 17 h prior to ischemia protected mice from IRI. Serum creatinine levels at 24 h after IRI were 0.13 ± 0.06 mg/dl (sham, n = 3), 1.59 ± 0.10 mg/dl (vehicle, n = 8) and 0.89 ± 0.11 mg/dl (meclizine, n = 8). Kidney injury was significantly decreased in meclizine treated mice compared with vehicle group (p < 0.001). Protection was also seen when meclizine was administered 24 h prior to ischemia. Meclizine reduced inflammation, mitochondrial oxygen consumption, oxidative stress, mitochondrial fragmentation, and tubular injury. Meclizine preconditioned kidney tubular epithelial cells, exposed to blockade of glycolytic and oxidative metabolism with 2-deoxyglucose and NaCN, had reduced LDH and cytochrome c release. Meclizine upregulated glycolysis in glucose-containing media and reduced cellular ATP levels in galactose-containing media. Meclizine inhibited the Kennedy pathway and caused rapid accumulation of phosphoethanolamine. Phosphoethanolamine recapitulated meclizine-induced protection both in vitro and in vivo. PMID:26501107

  14. Meclizine Preconditioning Protects the Kidney Against Ischemia-Reperfusion Injury.

    PubMed

    Kishi, Seiji; Campanholle, Gabriela; Gohil, Vishal M; Perocchi, Fabiana; Brooks, Craig R; Morizane, Ryuji; Sabbisetti, Venkata; Ichimura, Takaharu; Mootha, Vamsi K; Bonventre, Joseph V

    2015-09-01

    Global or local ischemia contributes to the pathogenesis of acute kidney injury (AKI). Currently there are no specific therapies to prevent AKI. Potentiation of glycolytic metabolism and attenuation of mitochondrial respiration may decrease cell injury and reduce reactive oxygen species generation from the mitochondria. Meclizine, an over-the-counter anti-nausea and -dizziness drug, was identified in a 'nutrient-sensitized' chemical screen. Pretreatment with 100 mg/kg of meclizine, 17 h prior to ischemia protected mice from IRI. Serum creatinine levels at 24 h after IRI were 0.13 ± 0.06 mg/dl (sham, n = 3), 1.59 ± 0.10 mg/dl (vehicle, n = 8) and 0.89 ± 0.11 mg/dl (meclizine, n = 8). Kidney injury was significantly decreased in meclizine treated mice compared with vehicle group (p < 0.001). Protection was also seen when meclizine was administered 24 h prior to ischemia. Meclizine reduced inflammation, mitochondrial oxygen consumption, oxidative stress, mitochondrial fragmentation, and tubular injury. Meclizine preconditioned kidney tubular epithelial cells, exposed to blockade of glycolytic and oxidative metabolism with 2-deoxyglucose and NaCN, had reduced LDH and cytochrome c release. Meclizine upregulated glycolysis in glucose-containing media and reduced cellular ATP levels in galactose-containing media. Meclizine inhibited the Kennedy pathway and caused rapid accumulation of phosphoethanolamine. Phosphoethanolamine recapitulated meclizine-induced protection both in vitro and in vivo. PMID:26501107

  15. Cyclooxygenase inhibition in ischemic brain injury

    E-print Network

    Eduardo Candelario-Jalil; Bernd L. Fiebich

    2008-07-09

    Neuroinflammation is one of the key pathological events involved in the progression of brain damage caused by cerebral ischemia. Metabolism of arachidonic acid through cyclooxygenase (COX) enzymes is known to be actively involved in the neuroinflammatory events leading to neuronal death after ischemia. Two isoforms of COX, termed COX-1 and COX-2, have been identified. Unlike COX-1, COX-2 expression is dramatically induced by ischemia and appears to be an effector of tissue damage. This review article will focus specifically on the involvement of COX isozymes in brain ischemia. We will discuss issues related to the biochemistry and selective pharmacological inhibition of COX enzymes, and further refer to their expression in the brain under normal conditions and following excitotoxicity and ischemic cerebral injury. We will review present knowledge of the relative contribution of each COX isoform to the brain ischemic pathology, based on data from investigations utilizing selective COX-1/COX-2 inhibitors and genetic knockout mouse models. The mechanisms of neurotoxicity associated with increased COX activity after ischemia will also be examined. Finally, we will provide a critical evaluation of the therapeutic potential of COX inhibitors in cerebral ischemia and discuss new targets downstream of COX with potential neuroprotective ability.

  16. Women and Ischemic Heart Disease: Evolving Knowledge

    PubMed Central

    Shaw, Leslee J.; Bugiardini, Raffaelle; Merz, C. Noel Bairey

    2009-01-01

    Evolving knowledge regarding sex differences in coronary heart disease (CHD) is emerging. Given the lower burden of obstructive coronary artery disease (CAD) and preserved systolic function in women contrasted by higher rates of myocardial ischemia and near-term mortality compared to men, we propose the term ischemic heart disease (IHD) as appropriate for this discussion specific to women, rather than CAD or CHD. This paradoxical difference where women have lower rates of anatomical CAD but more symptoms, ischemia, and outcomes appear linked to coronary reactivity which includes microvascular dysfunction. Novel risk factors can improve the Framingham risk score, including inflammatory markers and reproductive hormones, as well as noninvasive imaging and functional capacity measurements. Risk for women with obstructive CAD is elevated compared to men, yet women are less likely to receive guideline-indicated therapies. In the setting of non-ST elevation acute myocardial infarction, interventional strategies are equally effective in biomarker positive women and men, while conservative management is indicated for biomarker negative women. For women with evidence of ischemia but no obstructive CAD, anti-anginal and anti-ischemic therapies can improve symptoms, endothelial function, and quality of life; however trials evaluating adverse outcomes are needed. We hypothesize that women experience more adverse outcomes compared to men because obstructive CAD remains the current focus of therapeutic strategies. Continued research is indicated to devise therapeutic regimens to improve symptom burden and reduce risk in women with IHD. PMID:19833255

  17. Metabolic Prosthesis for Oxygenation of Ischemic Tissue

    SciTech Connect

    Greenbaum, Elias

    2009-01-01

    This communication discloses new ideas and preliminary results on the development of a "metabolic prosthesis" for local oxygenation of ischemic tissue under physiological neutral conditions. We report for the first time the selective electrolysis of physiological saline by repetitively pulsed charge-limited electrolysis for the production of oxygen and suppression of free chlorine. For example, using 800 A amplitude current pulses and <200 sec pulse durations, we demonstrated prompt oxygen production and delayed chlorine production at the surface of a shiny 0.85 mm diameter spherical platinum electrode. The data, interpreted in terms of the ionic structure of the electric double layer, suggest a strategy for in situ production of metabolic oxygen via a new class of "smart" prosthetic implants for dealing with ischemic disease such as diabetic retinopathy. We also present data indicating that drift of the local pH of the oxygenated environment can be held constant using a feedback-controlled three electrode electrolysis system that chooses anode and cathode pair based on pH data provided by local microsensors. The work is discussed in the context of diabetic retinopathy since surgical techniques for multielectrode prosthetic implants aimed at retinal degenerative diseases have been developed.

  18. Complement in the Homeostatic and Ischemic Brain

    PubMed Central

    Alawieh, Ali; Elvington, Andrew; Tomlinson, Stephen

    2015-01-01

    The complement system is a component of the immune system involved in both recognition and response to pathogens, and it is implicated in an increasing number of homeostatic and disease processes. It is well documented that reperfusion of ischemic tissue results in complement activation and an inflammatory response that causes post-reperfusion injury. This occurs following cerebral ischemia and reperfusion and triggers secondary damage that extends beyond the initial infarcted area, an outcome that has rationalized the use of complement inhibitors as candidate therapeutics after stroke. In the central nervous system, however, recent studies have revealed that complement also has essential roles in synaptic pruning, neurogenesis, and neuronal migration. In the context of recovery after stroke, these apparent divergent functions of complement may account for findings that the protective effect of complement inhibition in the acute phase after stroke is not always maintained in the subacute and chronic phases. The development of effective stroke therapies based on modulation of the complement system will require a detailed understanding of complement-dependent processes in both early neurodegenerative events and delayed neuro-reparatory processes. Here, we review the role of complement in normal brain physiology, the events initiating complement activation after cerebral ischemia-reperfusion injury, and the contribution of complement to both injury and recovery. We also discuss how the design of future experiments may better characterize the dual role of complement in recovery after ischemic stroke. PMID:26322048

  19. Using VoIP to compete.

    PubMed

    Werbach, Kevin

    2005-09-01

    Internet telephony, or VoIP, is rapidly replacing the conventional kind. This year, for the first time, U.S. companies bought more new Internet-phone connections than standard lines. The major driver behind this change is cost. But VoIP isn't just a new technology for making old-fashioned calls cheaper, says consultant Kevin Werbach. It is fundamentally changing how companies use voice communications. What makes VoIP so powerful is that it turns voice into digital data packets that can be stored, copied, combined with other data, and distributed to virtually any device that connects to the Internet. And it makes it simple to provide all the functionality of a corporate phone-call features, directories, security-to anyone anywhere there's broadband access. That fosters new kinds of businesses such as virtual call centers, where widely dispersed agents work at all hours from their homes. The most successful early adopters, says Werbach, will focus more on achieving business objectives than on saving money. They will also consider how to push VoIP capabilities out to the extended organization, making use of everyone as a resource. Deployment may be incremental, but companies should be thinking about where VoIP could take them. Executives should ask what they could do if, on demand, they could bring all their employees, customers, suppliers, and partners together in a virtual room, with shared access to every modern communications and computing channel. They should take a fresh look at their business processes to find points at which richer and more customizable communications could eliminate bottlenecks and enhance quality. The important dividing line won't be between those who deploy Vol P and those who don't, or even between early adopters and laggards. It will be between those who see Vol P as just a new way to do the same old things and those who use itto rethink their entire businesses. PMID:16171218

  20. Integrated IP telephony gateway and its stochastic petri net model

    NASA Astrophysics Data System (ADS)

    Huang, Yongfeng; Li, Xing

    2001-10-01

    With rapid development of computer network and a wide application of Internet, IP telephony has been realized. Currently, one of the most important research areas of IP telephony system is to develop the IP telephony gateway. In this paper, a new idea of design on an Integrated IP Telephony Gateway is proposed, and the hardware of Integrated IP Telephony is discussed in detail. The software architecture of the Integrated IP telephone gateway is studied, and this paper focus on the voice compression module and SPOX schedule module. In addition, Stochastic Petri Net Model of an Integrated IP Telephony Gateway is set up, and its performance analyzed through the Stochastic Petri Net model. Array of Petri Net Model is computed, and educes the mathematical relationship of CPU efficiency and structure parameters of the IP telephony gateway.

  1. Secure Voice over IP conferencing with decentralized group encryption

    E-print Network

    Kannan, Steven (Steven K.)

    2007-01-01

    This thesis addresses the development of an end-to-end secure Voice over IP (VoIP) conference system. We are particularly interested in challenges associated with deploying such a system in ad-hoc networks containing low ...

  2. Modeling and assessing secure Voice over IP performance

    E-print Network

    Zue, Cory L

    2005-01-01

    Voice over Internet Protocol (VoIP) systems enable efficient communications over data networks, but security of VoIP and the impact of that security on communications quality has not been quantitatively modeled. A ...

  3. IP- -: A Reduced Internet Protocol for Optical Packet Networking

    NASA Astrophysics Data System (ADS)

    Ohta, Masataka; Fujikawa, Kenji

    IP- - is proposed as an Internet Protocol suitable for optical packet networking. As optical routers require much faster control than electric ones and lack of optical buffers other than those by fiber delay lines requires fixed time control, Internet Protocols must be at least as simple as IPv4 and much simpler than IPv6. IP- - also addresses issues of IP address space exhaustion and IP routing table explosion.

  4. Flexible Deterministic Packet Marking: An IP Traceback System to Find

    E-print Network

    Guo, Minyi

    Flexible Deterministic Packet Marking: An IP Traceback System to Find the Real Source of Attacks--Internet Protocol (IP) traceback is the enabling technology to control Internet crime. In this paper, we present a novel and practical IP traceback system called Flexible Deterministic Packet Marking (FDPM) which

  5. Towards a global IP anycast service Paper 110, 14 Pages

    E-print Network

    Sirer, Emin Gun

    1 Towards a global IP anycast service Paper 110, 14 Pages Abstract IP anycast, with its innate ability to find nearby resources in a robust and efficient fashion, has long been considered an important means of service discovery. The growth of P2P ap- plications presents appealing new uses for IP anycast

  6. Mobile IP howto. Linux Red Hat 7.3

    E-print Network

    Schwefel, Hans-Peter

    Mobile IP howto. Linux Red Hat 7.3 Mobile IP software has been retrieved from Helsinki.8.1.tar.gz Checking and setting up Red Hat 7.3 The mobile IP software is developed to/on Linux Red Hat in the linux kernel directory and in the menu; most of them you can find under ì Networking optionsî

  7. Resolving IP Aliases with Prespecified Timestamps Justine Sherry

    E-print Network

    Anderson, Tom

    this issue by identi- fying some IP aliases, these techniques, even in combination, find only a subsetResolving IP Aliases with Prespecified Timestamps Justine Sherry Ethan Katz-Bassett Mary Pimenova for purposes including troubleshooting and modeling. However, tools such as traceroute return IP ad- dresses

  8. Covert Channels in SIP for VoIP Signalling

    NASA Astrophysics Data System (ADS)

    Mazurczyk, Wojciech; Szczypiorski, Krzysztof

    In this paper, we evaluate available steganographic techniques for SIP (Session Initiation Protocol) that can be used for creating covert channels during signaling phase of VoIP (Voice over IP) call. Apart from characterizing existing steganographic methods we provide new insights by introducing new techniques. We also estimate amount of data that can be transferred in signalling messages for typical IP telephony call.

  9. IP ROUTING ISSUES IN SATELLITE CONSTELLATION NETWORKS A. CLERGET,2

    E-print Network

    Wood, Lloyd

    1 IP ROUTING ISSUES IN SATELLITE CONSTELLATION NETWORKS L. WOOD,*1 A. CLERGET,2 I. ANDRIKOPOULOS,1 broadband satellite constellation networks, currently under development, will be required to transport IP traffic. A case can be made for implementing IP routing directly within the constellation network

  10. Teaching IP Core Development: An Example Aleksandar Milenkovic, David Fatzer

    E-print Network

    Milenkovi, Aleksandar

    Teaching IP Core Development: An Example Aleksandar Milenkovic, David Fatzer Electrical-on-a-chip (SoC) have led to the wide utilization of reusable intellectual property (IP) cores. Educators and use of IP cores, and to offer them a system perspective including both hardware and software. One way

  11. Controlling IP Spoofing Through Inter-Domain Packet Filters

    E-print Network

    Yuan, Xin

    -based attacks [10], and TCP SYN flood attacks [11], use IP spoofing and require the ability to forge sourceS) attack is a serious threat to the legitimate use of the Internet. Prevention mechanisms are thwarted by the ability of attackers to forge, or spoof, the source addresses in IP packets. By employing IP spoofing

  12. CISCO IP 7905/7906 / 7912 FONCTIONS TLPHONIQUES

    E-print Network

    Meunier, Michel

    CISCO IP 7905/7906 / 7912 FONCTIONS TÉLÉPHONIQUES FONCTIONS DE BASE Documentation Cisco_IP_7905'initiateur peut se retirer sans interrompre l'appel mais aucun autre participant ne pourra s'y ajouter. #12;CISCO à plusieurs personnes de se joindre à un appel conférence en cours. Documentation Cisco_IP_7905

  13. Detecting VoIP Floods Using the Hellinger Distance

    E-print Network

    Wang, Haining

    Detecting VoIP Floods Using the Hellinger Distance Hemant Sengar, Student Member, IEEE, Haining running over the TCP/IP suite, it is susceptible to flooding attacks. If flooded, as a time. Because multiple protocols are involved in a VoIP service and most of them are susceptible to flooding

  14. Is opium addiction a risk factor for ischemic heart disease and ischemic stroke?

    PubMed Central

    Rezvani, Mohammad Reza; Ghandehari, Kavian

    2012-01-01

    Background: The main source of studies about effects of opium consumption on heart and brain attacks originates from Iran Therefore the aim of the present study was to assess opium addiction as a probable influencing factor for ischemic heart disease and ischemic stroke. Materials and Methods: A cross-sectional study was carried out in two Cardiology and Neurology clinics in Eastern Iran in 2011. Diagnosis of Ischemic Heart Disease (IHD) and Ischemic Stroke (IS) was made by Cardiologist and Stroke Neurologist respectively. The influence of gender, hypertension, diabetes, hyperlipidemia, cigarette smoking, oral and inhaled opium consumption on distribution of IHD and IS were evaluated. Results: Five hundred fifty eight patients (307 females, 251 males) with mean age 56.2 years enrolled the study. On adjusted odds ratios of our whole 558 patients, only hypertension and diabetes had a significant influence on occurrence of IHD; (P = 0.000 and P = 0.000) respectively. Oral and inhaled routes of opium addiction did not have a significant effect on occurrence of IHD; [OR = 1.172, 95% CI = 0.624–2.203, P = 0.621] and [OR = 1.820, 95% CI = 0.811–4.085, P = 0.147] respectively. Hypertension and diabetes were significant risk factors of IS in our 558 patients at multivariate analysis; (P = 0.000, P = 0.020). Oral opium addiction was as significant protective factor of IS in our study group; OR = 0.211, 95% CI = 0.079–0.564, P = 0.002, while inhaled opium addiction did not have a significant effect on occurrence of IS in our patients at; OR = 1.760, 95% CI = 0.760–4.076, P = 0.187. Conclusion: Oral opium consumption is a protective factor of IS but not IHD. Inhaled opium addiction does not have a significant influence on occurrence of IS and IHD. PMID:23825997

  15. Optimization of OSPF Routing in IP Networks

    NASA Astrophysics Data System (ADS)

    Bley, Andreas; Fortz, Bernard; Gourdin, Eric; Holmberg, Kaj; Klopfenstein, Olivier; Pióro, Micha?; Tomaszewski, Artur; Ümit, Hakan

    The Internet is a huge world-wide packet switching network comprised of more than 13,000 distinct subnetworks, referred to as Autonomous Systems (ASs) autonomous system AS . They all rely on the Internet Protocol (IP) internet protocol IP for transport of packets across the network. And most of them use shortest path routing protocols shortest path routing!protocols , such as OSPF or IS-IS, to control the routing of IP packets routing!of IP packets within an AS. The idea of the routing is extremely simple — every packet is forwarded on IP links along the shortest route between its source and destination nodes of the AS. The AS network administrator can manage the routing of packets in the AS by supplying the so-called administrative weights of IP links, which specify the link lengths that are used by the routing protocols for their shortest path computations. The main advantage of the shortest path routing policy is its simplicity, allowing for little administrative overhead. From the network engineering perspective, however, shortest path routing can pose problems in achieving satisfactory traffic handling efficiency. As all routing paths depend on the same routing metric routing!metric , it is not possible to configure the routing paths for the communication demands between different pairs of nodes explicitly or individually; the routing can be controlled only indirectly and only as a whole by modifying the routing metric. Thus, one of the main tasks when planning such networks is to find administrative link weights that induce a globally efficient traffic routing traffic!routing configuration of an AS. It turns out that this task leads to very difficult mathematical optimization problems. In this chapter, we discuss and describe exact integer programming models and solution approaches as well as practically efficient smart heuristics for such shortest path routing problems shortest path routing!problems .

  16. In vivo detection of the effects of preconditioning on LNCaP tumors by a TNF-? nanoparticle construct using MRI

    PubMed Central

    Iltis, Isabelle; Choi, Jeunghwan; Vollmers, Manda; Shenoi, Mithun; Bischof, John; Metzger, Gregory J.

    2014-01-01

    The outcome of systemic and local therapies (e.g., chemotherapy, radiotherapy, surgery, focal ablation) for prostate cancer can be significantly improved by using tumor-specific adjuvants prior to treatment (“preconditioning”). We propose to use dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) to monitor the in vivo response of a mouse model of prostate cancer treated with a vascular disruptive agent, TNF-?, delivered on a gold nanoparticle (NP-TNF). Six male nude mice bearing 4–5 weeks old LNCaP tumors were scanned at 9.4T. DCE-MRI was performed two days before and 4–5 hours after treatment with NP-TNF. An intraperitoneal bolus of Gadolinium-DTPA (Gd) was administered and contrast enhancement was measured for 90 minutes. Concentration time curves of Gd were calculated and the area under the Gd curve (AUGC) was determined pre and post treatment. NP-TNF treatment caused an increase in contrast uptake in tumors. Interestingly, the early concentration (10 minutes post Gd bolus i.p.) was similar in both untreated and treated conditions; however, 90 minutes after injection, [Gd] was 3.4 times higher after treatment compared to before. AUGC doubled from 11 ± 6 [Gd] × min before treatment to 22 ± 9 [Gd] × min after treatment. An increase in signal enhancement was also observed in the muscle but to a lesser degree. We also evaluated the kinetics of intravenous gadolinium administration in mice bearing a jugular vein catheter to mimic the delivery method used in clinical trials. The overall treatment effects were independent of the delivery pathway of the contrast agent. In conclusion, we show that DCE-MRI is suitable to detect changes associated with a vascular disruptive agent in a mouse model of prostate cancer. The ability to characterize the effects of nanoparticle therapy in vivo with non-destructive methods is important as such compounds, in combination with treatment strategies, progress towards clinical trials. PMID:24980267

  17. Glaciations in response to climate variations preconditioned by evolving topography.

    PubMed

    Pedersen, Vivi Kathrine; Egholm, David Lundbek

    2013-01-10

    Landscapes modified by glacial erosion show a distinct distribution of surface area with elevation (hypsometry). In particular, the height of these regions is influenced by climatic gradients controlling the altitude where glacial and periglacial processes are the most active, and as a result, surface area is focused just below the snowline altitude. Yet the effect of this distinct glacial hypsometric signature on glacial extent and therefore on continued glacial erosion has not previously been examined. Here we show how this topographic configuration influences the climatic sensitivity of Alpine glaciers, and how the development of a glacial hypsometric distribution influences the intensity of glaciations on timescales of more than a few glacial cycles. We find that the relationship between variations in climate and the resulting variation in areal extent of glaciation changes drastically with the degree of glacial modification in the landscape. First, in landscapes with novel glaciations, a nearly linear relationship between climate and glacial area exists. Second, in previously glaciated landscapes with extensive area at a similar elevation, highly nonlinear and rapid glacial expansions occur with minimal climate forcing, once the snowline reaches the hypsometric maximum. Our results also show that erosion associated with glaciations before the mid-Pleistocene transition at around 950,000 years ago probably preconditioned the landscape--producing glacial landforms and hypsometric maxima--such that ongoing cooling led to a significant change in glacial extent and erosion, resulting in more extensive glaciations and valley deepening in the late Pleistocene epoch. We thus provide a mechanism that explains previous observations from exposure dating and low-temperature thermochronology in the European Alps, and suggest that there is a strong topographic control on the most recent Quaternary period glaciations. PMID:23302860

  18. Super-low Dose Endotoxin Pre-conditioning Exacerbates Sepsis Mortality

    PubMed Central

    Chen, Keqiang; Geng, Shuo; Yuan, Ruoxi; Diao, Na; Upchurch, Zachary; Li, Liwu

    2015-01-01

    Sepsis mortality varies dramatically in individuals of variable immune conditions, with poorly defined mechanisms. This phenomenon complements the hypothesis that innate immunity may adopt rudimentary memory, as demonstrated in vitro with endotoxin priming and tolerance in cultured monocytes. However, previous in vivo studies only examined the protective effect of endotoxin tolerance in the context of sepsis. In sharp contrast, we report herein that pre-conditioning with super-low or low dose endotoxin lipopolysaccharide (LPS) cause strikingly opposite survival outcomes. Mice pre-conditioned with super-low dose LPS experienced severe tissue damage, inflammation, increased bacterial load in circulation, and elevated mortality when they were subjected to cecal-ligation and puncture (CLP). This is in contrast to the well-reported protective phenomenon with CLP mice pre-conditioned with low dose LPS. Mechanistically, we demonstrated that super-low and low dose LPS differentially modulate the formation of neutrophil extracellular trap (NET) in neutrophils. Instead of increased ERK activation and NET formation in neutrophils pre-conditioned with low dose LPS, we observed significantly reduced ERK activation and compromised NET generation in neutrophils pre-conditioned with super-low dose LPS. Collectively, our findings reveal a mechanism potentially responsible for the dynamic programming of innate immunity in vivo as it relates to sepsis risks. PMID:26029736

  19. Neuroprotective Strategies after Neonatal Hypoxic Ischemic Encephalopathy.

    PubMed

    Dixon, Brandon J; Reis, Cesar; Ho, Wing Mann; Tang, Jiping; Zhang, John H

    2015-01-01

    Neonatal hypoxic ischemic encephalopathy (HIE) is a devastating disease that primarily causes neuronal and white matter injury and is among the leading cause of death among infants. Currently there are no well-established treatments; thus, it is important to understand the pathophysiology of the disease and elucidate complications that are creating a gap between basic science and clinical translation. In the development of neuroprotective strategies and translation of experimental results in HIE, there are many limitations and challenges to master based on an appropriate study design, drug delivery properties, dosage, and use in neonates. We will identify understudied targets after HIE, as well as neuroprotective molecules that bring hope to future treatments such as melatonin, topiramate, xenon, interferon-beta, stem cell transplantation. This review will also discuss some of the most recent trials being conducted in the clinical setting and evaluate what directions are needed in the future. PMID:26389893

  20. [Intravenous thrombolysis in ischemic stroke: Therapeutic perspectives].

    PubMed

    Paris, C; Derex, L

    2015-12-01

    New therapeutic strategies are under evaluation to improve the treatment of acute ischemic stroke (AIS). Approaches combining intravenous (IV) thrombolysis with recombinant tissue plasminogen activator (rt-PA) and antithrombotic agents are currently evaluated. The combination of IV rt-PA and aspirin showed a high rate of intracranial hemorrhage whereas the association of rt-PA and eptifibatide seems more promising. The results of recent studies evaluating the administration of eptifibatide or argatroban in conjunction with conventional IV thrombolysis with rt-PA are expected to clarify the safety and efficacy of these treatments. More fibrin-specific plasminogen activators, tenecteplase and desmoteplase, are also investigated. These fibrinolytic agents showed a favorable safety profile but their efficacy in AIS remains uncertain. While phase III studies, DIAS-3 and DIAS-4, evaluating IV desmoteplase up to nine hours after stroke onset did not meet the primary endpoint, the results of studies comparing IV tenecteplase and IV rt-PA are expected. PMID:26563662

  1. Hypoxic-ischemic leukoencephalopathy in man.

    PubMed

    Ginsberg, M D; Hedley-Whyte, E T; Richardson, E P

    1976-01-01

    Three cases of hypoxic-ischemic leukoencephalopathy were studied. In two patients, the neurologic disorder followed drug overdosage; in the third, the apparent precipitating event was a postoperative myocardial infarction complicated by circulatory insufficiency. All patients were deeply unresponsive, with varying reflex patterns. In all three cases, the brain showed extensive symmetrical necrotic lesions of the central white matter, with minimal damage to gray matter structures. The lesions in case 3 showed, in addition, vascular necrosis and ring hemorrhages. Common to all cases was a prolonged period of hypoxemia, hypotension, and elevated venous pressure. Acidosis occurred in two. These observations and analysis of previous reports of similar cases suggest that leukoencephalopathy tends to occur when the hypoxemia is prolonged and is associated with periods of hypotension and metabolic imbalance. PMID:1247396

  2. Targeting Neovascularization in Ischemic Retinopathy: Recent Advances

    PubMed Central

    Al-Shabrawey, Mohamed; Elsherbiny, Mohamed; Nussbaum, Julian; Othman, Amira; Megyerdi, Sylvia; Tawfik, Amany

    2014-01-01

    Pathological retinal neovascularization (RNV) is a common micro-vascular complication in several retinal diseases including retinopathy of prematurity, diabetic retinopathy, age-related macular degeneration and central vein occlusion. The current therapeutic modalities of RNV are invasive and although they may slow or halt the progression of the disease they are unlikely to restore normal acuity. Therefore, there is an urgent need to develop treatment modalities, which are less invasive and therefore associated with fewer procedural complications and systemic side effects. This review article summarizes our understanding of the pathophysiology and current treatment of RNV in ischemic retinopathies; lists potential therapeutic targets; and provides a framework for the development of future treatment modalities. PMID:25598837

  3. Hypothermia for newborns with hypoxic ischemic encephalopathy

    PubMed Central

    Peliowski-Davidovich, Abraham

    2012-01-01

    Hypoxic ischemic encephalopathy (HIE) remains a significant cause of mortality and long-term disability in late preterm and term infants. Mild therapeutic hypothermia to a rectal temperature of 34±0.5°C initiated as soon as possible within the first 6 h of life decreases mortality and severe long-term neurodevelopmental disabilities in infants with moderate HIE who are ?36 weeks’ gestational age. There are minimal side effects, and the incidence of disability in survivors is not increased. Infants with severe encephalopathy are less likely to benefit from treatment. Cooling may be achieved by either total body or selective head cooling. As cooling is now considered a standard of care, infants ?36 weeks’ gestational age who are depressed at birth should be assessed to determine whether they meet the criteria for cooling. There is currently no evidence that therapeutic hypothermia offers any benefit to infants <36 weeks’ gestational age. PMID:23277757

  4. Neuroprotective Strategies after Neonatal Hypoxic Ischemic Encephalopathy

    PubMed Central

    Dixon, Brandon J.; Reis, Cesar; Ho, Wing Mann; Tang, Jiping; Zhang, John H.

    2015-01-01

    Neonatal hypoxic ischemic encephalopathy (HIE) is a devastating disease that primarily causes neuronal and white matter injury and is among the leading cause of death among infants. Currently there are no well-established treatments; thus, it is important to understand the pathophysiology of the disease and elucidate complications that are creating a gap between basic science and clinical translation. In the development of neuroprotective strategies and translation of experimental results in HIE, there are many limitations and challenges to master based on an appropriate study design, drug delivery properties, dosage, and use in neonates. We will identify understudied targets after HIE, as well as neuroprotective molecules that bring hope to future treatments such as melatonin, topiramate, xenon, interferon-beta, stem cell transplantation. This review will also discuss some of the most recent trials being conducted in the clinical setting and evaluate what directions are needed in the future. PMID:26389893

  5. Curbing Inflammation in the Ischemic Heart Disease

    PubMed Central

    Evora, Paulo Roberto B.; Nather, Julio; Tubino, Paulo Victor; Albuquerque, Agnes Afrodite S.; Celotto, Andrea Carla; Rodrigues, Alfredo J.

    2013-01-01

    A modern concept considers acute coronary syndrome as an autoinflammatory disorder. From the onset to the healing stage, an endless inflammation has been presented with complex, multiple cross-talk mechanisms at the molecular, cellular, and organ levels. Inflammatory response following acute myocardial infarction has been well documented since the 1940s and 1950s, including increased erythrocyte sedimentation rate, the C-reactive protein analysis, and the determination of serum complement. It is surprising to note, based on a wide literature overview including the following 30 years (decades of 1960, 1970, and 1980), that the inflammatory acute myocardium infarction lost its focus, virtually disappearing from the literature reports. The reversal of this historical process occurs in the 1990s with the explosion of studies involving cytokines. Considering the importance of inflammation in the pathophysiology of ischemic heart disease, the aim of this paper is to present a conceptual overview in order to explore the possibility of curbing this inflammatory process. PMID:23819098

  6. Use of nitrates in ischemic heart disease.

    PubMed

    Giuseppe, Cocco; Paul, Jerie; Hans-Ulrich, Iselin

    2015-01-01

    Short-acting nitrates are beneficial in acute myocardial ischemia. However, many unresolved questions remain about the use of long-acting nitrates in stable ischemic heart disease. The use of long-acting nitrates is weakened by the development of endothelial dysfunction and tolerance. Also, we currently ignore whether lower doses of transdermal nitroglycerin would be better than those presently used. Multivariate analysis data from large nonrandomized studies suggested that long-acting nitrates increase the incidence of acute coronary syndromes, while data from another multivariate study indicate that they have positive effects. Because of methodological differences and open questions, the two studies cannot be compared. A study in Japanese patients with vasospastic angina has shown that, when compared with calcium antagonists, long-acting nitrates do not improve long-term prognosis and that the risk for cardiac adverse events increases with the combined therapy. We have many unanswered questions. PMID:26027641

  7. Green Space and Mortality Following Ischemic Stroke

    PubMed Central

    Wilker, Elissa H.; Wu, Chih-Da; McNeely, Eileen; Mostofsky, Elizabeth; Spengler, John; Wellenius, Gregory A.; Mittleman, Murray A.

    2014-01-01

    Background Residential proximity to green space has been associated with physical and mental health benefits, but whether green space is associated with post-stroke survival has not been studied. Methods Patients ?21 years of age admitted to the Beth Israel Deaconess Medical Center (BIDMC) between 1999 and 2008 with acute ischemic stroke were identified. Demographics, presenting symptoms, medical history and imaging results were abstracted from medical records at the time of hospitalization for stroke onset. Addresses were linked to average Normalized Difference Vegetation Index, distance to roadways with more than 10,000 cars/day, and US census block group. Deaths were identified through June 2012 using the Social Security Death Index. Results There were 929 deaths among 1,645 patients with complete data (median follow up: 5 years). In multivariable Cox models adjusted for indicators of medical history, demographic and socioeconomic factors, the hazard ratio for patients living in locations in the highest quartile of green space compared to the lowest quartile was 0.78 (95% Confidence Interval: 0.63 to 0.97) (p-trend=0.009). This association remained statistically significant after adjustment for residential proximity to a high traffic road. Conclusions Residential proximity to green space is associated with higher survival rates after ischemic stroke in multivariable adjusted models. Further work is necessary to elucidate the underlying mechanisms for this association, and to better understand the exposure-response relationships and susceptibility factors that may contribute to higher mortality in low green space areas. PMID:24906067

  8. +TIPs: SxIPping along microtubule ends

    PubMed Central

    Kumar, Praveen; Wittmann, Torsten

    2012-01-01

    +TIPs are a heterogeneous class of proteins that specifically bind to growing microtubule ends. Because dynamic microtubules are essential for many intracellular processes, +TIPs likely play important roles in regulating microtubule dynamics and microtubule interactions with other intracellular structures. End-binding proteins (EBs) recognize a structural cap at growing microtubule ends, and have emerged as central adaptors that mediate microtubule plus-end-tracking of potentially all other +TIPs. The majority of these +TIPs bind EBs through a short hydrophobic SxIP sequence motif and surrounding electrostatic interactions. These recent discoveries have resulted in a rapid expansion of the number of possible +TIPs. In this review, we outline our current understanding of the molecular mechanism of plus-end-tracking and provide an overview of SxIP-recruited +TIPs. PMID:22748381

  9. IP3 signalling regulates exogenous RNAi in Caenorhabditis elegans

    PubMed Central

    Lopez, Marie; Christov, Christo P; Sequedo, María Dolores; Herzog, Mareike; Herlihy, Anna E; Bodak, Maxime; Gatsi, Roxani; Baylis, Howard A.

    2014-01-01

    RNA interference (RNAi) is a widespread and widely exploited phenomenon. Here we show that changing inositol 1,4,5-trisphosphate (IP3) signalling alters RNAi sensitivity in C. elegans. Reducing IP3 signalling enhances sensitivity to RNAi in a broad range of genes and tissues. Conversely up-regulating IP3 signalling decreases sensitivity. Tissue specific rescue experiments suggest IP3 functions in the intestine. We also exploit IP3 signalling mutants to further enhance the sensitivity of RNAi hypersensitive strains. These results demonstrate that a conserved cell signalling pathways can modify RNAi responses, implying that RNAi responses may be influenced by an animal’s physiology or environment. PMID:25608529

  10. Technology Transfer Center | Sample IP Management Plans

    Cancer.gov

    This page provides general guidance for preparation of IP Management Plans and lists various sample plans that can be used by extramural funding applicants to prepare intellectual property management plans when required by program announcements that cite this website as a resource. These sample plans are provided to assist applicants in preparing the intellectual property management plans in their partnerships with industry in order to meet certain programmatic objectives and goals of particular funding announcements.

  11. Chromatin Immunoprecipitation (ChIP) Required Solutions

    E-print Network

    de Lange, Titia

    Chromatin Immunoprecipitation (ChIP) Required Solutions 10x PBS 80 g NaCl 2 g KCl 17.4 g Na2HPO4.7H-HCl pH 7.0 1 M NaPi pH 7.2 In 2.3 liters (orange capped roller bottle filled to shoulder). 308 g Na2HPO4

  12. Source identification of the Arctic sea ice proxy IP25.

    PubMed

    Brown, T A; Belt, S T; Tatarek, A; Mundy, C J

    2014-01-01

    Analysis of the organic geochemical biomarker IP25 in marine sediments is an established method for carrying out palaeo sea ice reconstructions for the Arctic. Such reconstructions cover timescales from decades back to the early Pleistocene, and are critical for understanding past climate conditions on Earth and for informing climate prediction models. Key attributes of IP25 include its strict association with Arctic sea ice together with its ubiquity and stability in underlying marine sediments; however, the sources of IP25 have remained undetermined. Here we report the identification of IP25 in three (or four) relatively minor (<5%) sea ice diatoms isolated from mixed assemblages collected from the Canadian Arctic. In contrast, IP25 was absent in the dominant taxa. Chemical and taxonomical investigations suggest that the IP25-containing taxa represent the majority of producers and are distributed pan-Arctic, thus establishing the widespread applicability of the IP25 proxy for palaeo Arctic sea ice reconstruction. PMID:24939562

  13. IP address management : augmenting Sandia's capabilities through open source tools.

    SciTech Connect

    Nayar, R. Daniel

    2005-08-01

    Internet Protocol (IP) address management is an increasingly growing concern at Sandia National Laboratories (SNL) and the networking community as a whole. The current state of the available IP addresses indicates that they are nearly exhausted. Currently SNL doesn't have the justification to obtain more IP address space from Internet Assigned Numbers Authority (IANA). There must exist a local entity to manage and allocate IP assignments efficiently. Ongoing efforts at Sandia have been in the form of a multifunctional database application notably known as Network Information System (NWIS). NWIS is a database responsible for a multitude of network administrative services including IP address management. This study will explore the feasibility of augmenting NWIS's IP management capabilities utilizing open source tools. Modifications of existing capabilities to better allocate available IP address space are studied.

  14. Cell Reprogramming, IPS Limitations, and Overcoming Strategies in Dental Bioengineering

    PubMed Central

    Ibarretxe, Gaskon; Alvarez, Antonia; Cañavate, Maria-Luz; Hilario, Enrique; Aurrekoetxea, Maitane; Unda, Fernando

    2012-01-01

    The procurement of induced pluripotent stem cells, or IPS cells, from adult differentiated animal cells has the potential to revolutionize future medicine, where reprogrammed IPS cells may be used to repair disease-affected tissues on demand. The potential of IPS cell technology is tremendous, but it will be essential to improve the methodologies for IPS cell generation and to precisely evaluate each clone and subclone of IPS cells for their safety and efficacy. Additionally, the current state of knowledge on IPS cells advises that research on their regenerative properties is carried out in appropriate tissue and organ systems that permit a safe assessment of the long-term behavior of these reprogrammed cells. In the present paper, we discuss the mechanisms of cell reprogramming, current technical limitations of IPS cells for their use in human tissue engineering, and possibilities to overcome them in the particular case of dental regeneration. PMID:22690226

  15. Peri-operative anaesthetic myocardial preconditioning and protection – cellular mechanisms and clinical relevance in cardiac anaesthesia

    PubMed Central

    Kunst, G; Klein, A A

    2015-01-01

    Preconditioning has been shown to reduce myocardial damage caused by ischaemia–reperfusion injury peri-operatively. Volatile anaesthetic agents have the potential to provide myocardial protection by anaesthetic preconditioning and, in addition, they also mediate renal and cerebral protection. A number of proof-of-concept trials have confirmed that the experimental evidence can be translated into clinical practice with regard to postoperative markers of myocardial injury; however, this effect has not been ubiquitous. The clinical trials published to date have also been too small to investigate clinical outcome and mortality. Data from recent meta-analyses in cardiac anaesthesia are also not conclusive regarding intra-operative volatile anaesthesia. These inconclusive clinical results have led to great variability currently in the type of anaesthetic agent used during cardiac surgery. This review summarises experimentally proposed mechanisms of anaesthetic preconditioning, and assesses randomised controlled clinical trials in cardiac anaesthesia that have been aimed at translating experimental results into the clinical setting. PMID:25764404

  16. Efficient Multi-Stage Time Marching for Viscous Flows via Local Preconditioning

    NASA Technical Reports Server (NTRS)

    Kleb, William L.; Wood, William A.; vanLeer, Bram

    1999-01-01

    A new method has been developed to accelerate the convergence of explicit time-marching, laminar, Navier-Stokes codes through the combination of local preconditioning and multi-stage time marching optimization. Local preconditioning is a technique to modify the time-dependent equations so that all information moves or decays at nearly the same rate, thus relieving the stiffness for a system of equations. Multi-stage time marching can be optimized by modifying its coefficients to account for the presence of viscous terms, allowing larger time steps. We show it is possible to optimize the time marching scheme for a wide range of cell Reynolds numbers for the scalar advection-diffusion equation, and local preconditioning allows this optimization to be applied to the Navier-Stokes equations. Convergence acceleration of the new method is demonstrated through numerical experiments with circular advection and laminar boundary-layer flow over a flat plate.

  17. Preconditioning for the Navier-Stokes equations with finite-rate chemistry

    NASA Technical Reports Server (NTRS)

    Godfrey, Andrew G.; Walters, Robert W.; Van Leer, Bram

    1993-01-01

    The preconditioning procedure for generalized finite-rate chemistry and the proper preconditioning for the one-dimensional Navier-Stokes equations are presented. Eigenvalue stiffness is resolved and convergence-rate acceleration is demonstrated over the entire Mach-number range from the incompressible to the hypersonic. Specific benefits are realized at low and transonic flow speeds. The extended preconditioning matrix accounts for thermal and chemical non-equilibrium and its implementation is explained for both explicit and implicit time marching. The effect of higher-order spatial accuracy and various flux splittings is investigated. Numerical analysis reveals the possible theoretical improvements from using proconditioning at all Mach numbers. Numerical results confirm the expectations from the numerical analysis. Representative test cases include flows with previously troublesome embedded high-condition-number regions.

  18. Novel Genes Critical for Hypoxic Preconditioning in Zebrafish Are Regulators of Insulin and Glucose Metabolism

    PubMed Central

    Manchenkov, Tania; Pasillas, Martina P.; Haddad, Gabriel G.; Imam, Farhad B.

    2015-01-01

    Severe hypoxia is a common cause of major brain, heart, and kidney injury in adults, children, and newborns. However, mild hypoxia can be protective against later, more severe hypoxia exposure via “hypoxic preconditioning,” a phenomenon that is not yet fully understood. Accordingly, we have established and optimized an embryonic zebrafish model to study hypoxic preconditioning. Using a functional genomic approach, we used this zebrafish model to identify and validate five novel hypoxia-protective genes, including irs2, crtc3, and camk2g2, which have been previously implicated in metabolic regulation. These results extend our understanding of the mechanisms of hypoxic preconditioning and affirm the discovery potential of this novel vertebrate hypoxic stress model. PMID:25840431

  19. Wide-field fluorescence molecular tomography with compressive sensing based preconditioning

    PubMed Central

    Yao, Ruoyang; Pian, Qi; Intes, Xavier

    2015-01-01

    Wide-field optical tomography based on structured light illumination and detection strategies enables efficient tomographic imaging of large tissues at very fast acquisition speeds. However, the optical inverse problem based on such instrumental approach is still ill-conditioned. Herein, we investigate the benefit of employing compressive sensing-based preconditioning to wide-field structured illumination and detection approaches. We assess the performances of Fluorescence Molecular Tomography (FMT) when using such preconditioning methods both in silico and with experimental data. Additionally, we demonstrate that such methodology could be used to select the subset of patterns that provides optimal reconstruction performances. Lastly, we compare preconditioning data collected using a normal base that offers good experimental SNR against that directly acquired with optimal designed base. An experimental phantom study is provided to validate the proposed technique. PMID:26713202

  20. Sexual dimorphism in ischemic stroke: lessons from the laboratory

    PubMed Central

    Manwani, Bharti; McCullough, Louise D

    2011-01-01

    Ischemic stroke is emerging as a major health problem for elderly women. Women have lower stroke incidence than men until an advanced age, when the epidemiology of ischemic stroke shifts and incidence rises dramatically in women. Experimental models of rodent stroke have replicated this clinical epidemiology, with exacerbated injury in older compared with young female rodents Many of the detrimental effects of aging on ischemic stroke outcome in females can be replicated by ovariectomy, suggesting that hormones such as estrogen play a neuroprotective role. However, emerging data suggest that the molecular mechanisms leading to ischemic cell death differ in the two sexes, and these effects may be independent of circulating hormone levels. This article highlights recent clinical and experimental literature on sex differences in stroke outcomes and mechanisms. PMID:21612353

  1. The Migraine-Ischemic Stroke Relation in Young Adults

    PubMed Central

    Pezzini, Alessandro; Del Zotto, Elisabetta; Giossi, Alessia; Volonghi, Irene; Costa, Paolo; Dalla Volta, Giorgio; Padovani, Alessandro

    2011-01-01

    In spite of the strong epidemiologic evidence linking migraine and ischemic stroke in young adults, the mechanisms explaining this association remain poorly understood. The observation that stroke occurs more frequently during the interictal phase of migraine prompts to speculation that an indirect relation between the two diseases might exist. In this regard, four major issues might be considered which may be summarized as follows: (1) the migraine-ischemic stroke relation is influenced by specific risk factors such as patent foramen ovale or endothelial dysfunction and more frequent in particular conditions like spontaneous cervical artery dissection; (2) migraine is associated with an increased prevalence of cardiovascular risk factors; (3) the link is caused by migraine-specific drugs; (4) migraine and ischemic vascular events are linked via a genetic component. In the present paper, we will review epidemiological studies, discuss potential mechanisms of migraine-induced stroke and comorbid ischemic stroke, and pose new research questions. PMID:21197470

  2. Therapeutically Targeting Neuroinflammation and Microglia after Acute Ischemic Stroke

    PubMed Central

    Lee, Sang-Rae; Choi, Sung S.; Chang, Kyu-Tae

    2014-01-01

    Inflammation has a pivotal role in the pathogenesis of ischemic stroke, and recent studies posit that inflammation acts as a double-edged sword, not only detrimentally augmenting secondary injury, but also potentially promoting recovery. An initial event of inflammation in ischemic stroke is the activation of microglia, leading to production of both pro- and anti-inflammatory mediators acting through multiple receptor signaling pathways. In this review, we discuss the role of microglial mediators in acute ischemic stroke and elaborate on preclinical and clinical studies focused on microglia in stroke models. Understanding how microglia can lead to both pro- and anti-inflammatory responses may be essential to implement therapeutic strategies using immunomodulatory interventions in ischemic stroke. PMID:25089266

  3. Relationship between adiponectin receptor 1 gene polymorphisms and ischemic stroke

    PubMed Central

    Han, Qian; Shu, Zunhua; Liang, Xuemei; Mi, Rui; Yang, Lei; Li, Peng

    2015-01-01

    Objective: Previous study suggested adiponectin receptor 2 (ADIPOR2) genetic polymorphisms were associated with the risk of ischemic stroke. However, the relation between adiponectin receptor 1 (ADIPOR1) gene polymorphism and stroke remains unclear. Methods: In the present study, we utilized the polymerase chain reaction-sequencing method to detect rs2275737 and s1342387 genotypes of ADIPOR1 gene in 300 cases of ischemic stroke patients and 300 age- and sex- matched healthy controls. Results: For rs2275737, we found A allele carriers have increased risk to ischemic stroke (OR=2.570, 95% CI: 1.999-3.305); also, we found rs1342387 A allele was associated with the risk for stroke (OR=1.351, 95% CI: 1.074-1.699). After adjusted for confounders such as hypertension, diabetes, and smoking, we found the association remains significant. Conclusion: ADIPOR1 genetic polymorphism may increase the risk of ischemic stroke.

  4. A robust locally preconditioned semi-coarsening multigrid algorithm for the 2-D Navier-Stokes equations 

    E-print Network

    Cain, Michael D

    1999-01-01

    preconditioning for an upwind discrimination of the Navier-stokes equations. A block Jacobi iterative scheme is used because of its high frequency error mode damping ability. At low Mach numbers, the performance of a flux preconditioned is investigated. The flux...

  5. Trans Fat, Aspirin, and Ischemic Stroke in Postmenopausal Women

    PubMed Central

    Yaemsiri, Sirin; Sen, Souvik; Tinker, Lesley; Rosamond, Wayne; Wassertheil-Smoller, Sylvia; He, Ka

    2012-01-01

    Objective To examine the associations between dietary fat intake and ischemic stroke among postmenopausal women. Methods We conducted a prospective cohort study of 87,025 generally healthy postmenopausal women (age 50–79 years) enrolled in the Women’s Health Initiative Observational Study. Repeated and validated dietary assessments were done using a self-administered food frequency questionnaire. We used Cox proportional hazards models to estimate hazard ratios (HR) of ischemic stroke based on quintiles of the cumulative average of fat intake. Results We documented 1,049 incident cases of ischemic stroke over 663,041 person-years of follow-up. Women in the highest quintile of trans fat intake had a significantly higher incidence of ischemic stroke (HR 1.39, 95% confidence interval [CI] 1.08–1.79, P-trend = 0.048) compared with women in the lowest quintile, while controlling for multiple covariates. The observed association was modified by aspirin use (P-interaction=0.02). The HR was 1.66 (95% CI 1.21–2.36, P-trend<0.01) among baseline non-aspirin users (n=67,288) and 0.95 (95% CI 0.60–1.48, P-trend=0.43) among aspirin users (n=19,736). No significant associations were found between intakes of saturated, monounsaturated, or polyunsaturated fat and ischemic stroke or any ischemic stroke subtypes. Interpretation In this large cohort of postmenopausal women, higher intake of trans fat was associated with incident ischemic stroke independent of major lifestyle/dietary factors. Aspirin use may attenuate the potential adverse effect of trans fat intake on ischemic stroke. PMID:22383309

  6. Preconditioning electromyographic data for an upper extremity model using neural networks

    NASA Technical Reports Server (NTRS)

    Roberson, D. J.; Fernjallah, M.; Barr, R. E.; Gonzalez, R. V.

    1994-01-01

    A back propagation neural network has been employed to precondition the electromyographic signal (EMG) that drives a computational model of the human upper extremity. This model is used to determine the complex relationship between EMG and muscle activation, and generates an optimal muscle activation scheme that simulates the actual activation. While the experimental and model predicted results of the ballistic muscle movement are very similar, the activation function between the start and the finish is not. This neural network preconditions the signal in an attempt to more closely model the actual activation function over the entire course of the muscle movement.

  7. Solving nonlinear heat conduction problems with multigrid preconditioned Newton-Krylov methods

    SciTech Connect

    Rider, W.J.; Knoll, D.A.

    1997-09-01

    Our objective is to investigate the utility of employing multigrid preconditioned Newton-Krylov methods for solving initial value problems. Multigrid based method promise better performance from the linear scaling associated with them. Our model problem is nonlinear heat conduction which can model idealized Marshak waves. Here we will investigate the efficiency of using a linear multigrid method to precondition a Krylov subspace method. In effect we will show that a fixed point nonlinear iterative method provides an effective preconditioner for the nonlinear problem.

  8. Propulsion-related flowfields using the preconditioned Navier-Stokes equations

    NASA Technical Reports Server (NTRS)

    Venkateswaran, S.; Weiss, J. M.; Merkle, C. L.; Choi, Y.-H.

    1992-01-01

    A previous time-derivative preconditioning procedure for solving the Navier-Stokes is extended to the chemical species equations. The scheme is implemented using both the implicit ADI and the explicit Runge-Kutta algorithms. A new definition for time-step is proposed to enable grid-independent convergence. Several examples of both reacting and non-reacting propulsion-related flowfields are considered. In all cases, convergence that is superior to conventional methods is demonstrated. Accuracy is verified using the example of a backward facing step. These results demonstrate that preconditioning can enhance the capability of density-based methods over a wide range of Mach and Reynolds numbers.

  9. Preconditioning for the Navier-Stokes equations with finite-rate chemistry

    NASA Technical Reports Server (NTRS)

    Godfrey, Andrew G.

    1993-01-01

    The extension of Van Leer's preconditioning procedure to generalized finite-rate chemistry is discussed. Application to viscous flow is begun with the proper preconditioning matrix for the one-dimensional Navier-Stokes equations. Eigenvalue stiffness is resolved and convergence-rate acceleration is demonstrated over the entire Mach-number range from nearly stagnant flow to hypersonic. Specific benefits are realized at the low and transonic flow speeds typical of complete propulsion-system simulations. The extended preconditioning matrix necessarily accounts for both thermal and chemical nonequilibrium. Numerical analysis reveals the possible theoretical improvements from using a preconditioner for all Mach number regimes. Numerical results confirm the expectations from the numerical analysis. Representative test cases include flows with previously troublesome embedded high-condition-number areas. Van Leer, Lee, and Roe recently developed an optimal, analytic preconditioning technique to reduce eigenvalue stiffness over the full Mach-number range. By multiplying the flux-balance residual with the preconditioning matrix, the acoustic wave speeds are scaled so that all waves propagate at the same rate, an essential property to eliminate inherent eigenvalue stiffness. This session discusses a synthesis of the thermochemical nonequilibrium flux-splitting developed by Grossman and Cinnella and the characteristic wave preconditioning of Van Leer into a powerful tool for implicitly solving two and three-dimensional flows with generalized finite-rate chemistry. For finite-rate chemistry, the state vector of unknowns is variable in length. Therefore, the preconditioning matrix extended to generalized finite-rate chemistry must accommodate a flexible system of moving waves. Fortunately, no new kind of wave appears in the system. The only existing waves are entropy and vorticity waves, which move with the fluid, and acoustic waves, which propagate in Mach number dependent directions. The nonequilibrium vibrational energies and species densities in the unknown state vector act strictly as convective waves. The essential concept for extending the preconditioning to generalized chemistry models is determining the differential variables which symmetrize the flux Jacobians. The extension is then straight-forward. This algorithm research effort will be released in a future version of the production level computational code coined the General Aerodynamic Simulation Program (GASP), developed by Walters, Slack, and McGrory.

  10. Demonstrating a Realistic IP Mission Prototype

    NASA Technical Reports Server (NTRS)

    Rash, James; Ferrer, Arturo B.; Goodman, Nancy; Ghazi-Tehrani, Samira; Polk, Joe; Johnson, Lorin; Menke, Greg; Miller, Bill; Criscuolo, Ed; Hogie, Keith

    2003-01-01

    Flight software and hardware and realistic space communications environments were elements of recent demonstrations of the Internet Protocol (IP) mission concept in the lab. The Operating Missions as Nodes on the Internet (OMNI) Project and the Flight Software Branch at NASA/GSFC collaborated to build the prototype of a representative space mission that employed unmodified off-the-shelf Internet protocols and technologies for end-to-end communications between the spacecraft/instruments and the ground system/users. The realistic elements used in the prototype included an RF communications link simulator and components of the TRIANA mission flight software and ground support system. A web-enabled camera connected to the spacecraft computer via an Ethernet LAN represented an on-board instrument creating image data. In addition to the protocols at the link layer (HDLC), transport layer (UDP, TCP), and network (IP) layer, a reliable file delivery protocol (MDP) at the application layer enabled reliable data delivery both to and from the spacecraft. The standard Network Time Protocol (NTP) performed on-board clock synchronization with a ground time standard. The demonstrations of the prototype mission illustrated some of the advantages of using Internet standards and technologies for space missions, but also helped identify issues that must be addressed. These issues include applicability to embedded real-time systems on flight-qualified hardware, range of applicability of TCP, and liability for and maintenance of commercial off-the-shelf (COTS) products. The NASA Earth Science Technology Office (ESTO) funded the collaboration to build and demonstrate the prototype IP mission.

  11. [Primary and secondary prevention of ischemic stroke].

    PubMed

    Awada, Adnan

    2011-01-01

    Primary prevention is aimed at reducing the risk of stroke in asymptomatic people. The most effective prevention is through control of modifiable risk factors. Adequate blood pressure reduction, cessation of cigarette smoking and use of antithrombotic therapy in atrial fibrillation are the most effective measures. Carotid endarterectomy may be useful in selected patients. Although very useful for health in general, tight control of diabetes and hypercholesterolemia, physical exercise and alimentary diet did not show a major influence for primary stroke prevention. Aspirin seems to be not very effective for primary stroke prevention, whereas some ACE inhibitors (e.g. ramipril), ARBs (e.g. losartan) or statins, may have a preventive role beyond their antihypertensive or hypocholesterolemic properties. Secondary stroke prevention is aimed at reducing the risk of recurrence after a first stroke or transient ischemic attack. Acting on risk factors is probably as effective as in primary prevention. Carotid endarterectomy for symptomatic stenoses > 70% and anticoagulation in patients with atrial fibrillation are by far the most effective measures. Antiplatelet therapy (aspirin, ticlopidine, clopidogrel and long acting dipyridamole-aspirine association) reduces significantly stroke recurrence. Most recent data suggest also that perindopril, eprosartan and some statins are beneficial against stroke recurrence even in normotensive and normocholesterolemic patients. PMID:22746010

  12. Human Data Supporting Glyburide in Ischemic Stroke.

    PubMed

    Sheth, Kevin N; Simard, J Marc; Elm, Jordan; Kronenberg, Golo; Kunte, Hagen; Kimberly, W Taylor

    2016-01-01

    The SUR1-TRPM4 channel is a critical determinant of edema and hemorrhagic transformation after focal ischemia. Blockade of this channel by the small molecule glyburide results in improved survival and neurological outcome in multiple preclinical models of ischemic stroke. A robust, compelling body of evidence suggests that an intravenous formulation of glyburide, RP-1127, can prevent swelling and improve outcome in patients with stroke. Retrospective studies of diabetic stroke patients show improved outcomes in patients who are continued on sulfonylureas after stroke onset. An early phase II study using magnetic resonance imaging and plasma biomarkers supports the conclusion that RP-1127 may decrease swelling and hemorrhagic transformation. Finally, the ongoing phase II RP-1127 development program has demonstrated continued safety as well as feasibility of enrollment and tolerability of the intervention. Continued efforts to complete the ongoing phase II study and definitive efficacy studies are needed to bring a candidate pharmacotherapy to a population of severe stroke patients that currently have no alternative. PMID:26463916

  13. Stem Cell Therapy for Ischemic Heart Disease

    PubMed Central

    Jameel, Mohammad Nurulqadr

    2010-01-01

    Abstract Stem cell transplantation has emerged as a novel treatment option for ischemic heart disease. Different cell types have been utilized and the recent development of induced pluripotent stem cells has generated tremendous excitement in the regenerative field. Bone marrow-derived multipotent progenitor cell transplantation in preclinical large animal models of postinfarction left ventricular remodeling has demonstrated long-term functional and bioenergetic improvement. These beneficial effects are observed despite no significant engraftment of bone marrow cells in the myocardium and even lower differentiation of these cells into cardiomyocytes. It is thought to be related to the paracrine effect of these stem cells, which secrete factors that lead to long-term gene expression changes in the host myocardium, thereby promoting neovascularization, inhibiting apoptosis, and stimulating resident cardiac progenitor cells. Future studies are warranted to examine the changes in the recipient myocardium after stem cell transplantation and to investigate the signaling pathways involved in these effects. Antioxid. Redox Signal. 13, 1879–1897. PMID:20687781

  14. Data considerations in ischemic stroke trials.

    PubMed

    Liebeskind, David S; Feldmann, Edward

    2014-05-01

    Data drive the analyses of any ischemic stroke trial, culminating in the main results and potential next steps. The distinct purpose of a given trial, advancing a novel treatment or examining routine clinical practice, determines the nature of essential data elements. Information gathering for an effective trial depends on ample data, adequate infrastructure, and properly planned statistical analyses. This review highlights the fact that successful future trials will require appropriate expertise that extends far beyond these basic considerations in order to move from identification of basic risk factors that are associated with outcomes to knowledge of pathophysiology and causation of outcomes. Efficient and productive data collection by local and central sites must be complemented by expert core lab adjudications. Source data archiving, including complete DICOM imaging datasets or biological specimens, are needed to maximize the potential for study interpretation and financial investment. Standard terminology, such as common data elements and definitions, enhance study comparisons. Screening logs attest to generalizability of a study. Real-time data transmission and core lab evaluation will be critical to guide adaptive trial design. Despite the overwhelming focus on the intervention in a particular treatment trial, individual pathophysiology must be considered. Understanding individual subject characteristics is a tenet of the coming era of precision stroke care, where the course of a given patient and eventual outcome is paramount. This will require a new approach to data collection in clinical trials. PMID:24641718

  15. Drug Treatment of Acute Ischemic Stroke

    PubMed Central

    Bansal, Sameer; Sangha, Kiranpal S.; Khatri, Pooja

    2013-01-01

    Acute ischemic stroke (AIS) is the fourth leading cause of death and the leading cause of adult disability in the USA. AIS most commonly occurs when a blood vessel is obstructed leading to irreversible brain injury and subsequent focal neurologic deficits. Drug treatment of AIS involves intravenous thrombolysis with alteplase (recombinant tissue plasminogen activator [rtPA]). Intravenous alteplase promotes thrombolysis by hydrolyzing plasminogen to form the proteolytic enzyme plasmin. Plasmin targets the blood clot with limited systemic thrombolytic effects. Alteplase must be administered within a short time window to appropriate patients to optimize its therapeutic efficacy. Recent trials have shown this time window may be extended from 3 to 4.5 hours in select patients. Other acute supportive interventions for AIS include maintaining normoglycemia, euthermia and treating severe hypertension. Urgent anticoagulation for AIS has generally not shown benefits that exceed the hemorrhage risks in the acute setting. Urgent antiplatelet use for AIS has limited benefits and should only promptly be initiated if alteplase was not administered, or after 24 hours if alteplase was administered. The majority of AIS patients do not receive thrombolytic therapy due to late arrival to emergency departments and currently there is a paucity of acute interventions for them. Ongoing clinical trials may lead to further medical breakthroughs to limit the damage inflicted by this devastating disease. PMID:23381911

  16. Persistent Ischemic Stroke Disparities despite Declining Incidence in Mexican Americans

    PubMed Central

    Morgenstern, Lewis B.; Smith, Melinda A.; Sanchez, Brisa N.; Brown, Devin L.; Zahuranec, Darin B.; Garcia, Nelda; Kerber, Kevin A.; Skolarus, Lesli E.; Meurer, William J.; Burke, James F.; Adelman, Eric E.; Baek, Jonggyu; Lisabeth, Lynda D.

    2015-01-01

    Objective To determine trends in ischemic stroke incidence among Mexican Americans and non-Hispanic whites. Methods We performed population-based stroke surveillance from January 1, 2000 to December 31, 2010 in Corpus Christi, Texas. Ischemic stroke patients 45 years and older were ascertained from potential sources, and charts were abstracted. Neurologists validated cases based on source documentation blinded to ethnicity and age. Crude and age-, sex-, and ethnicity-adjusted annual incidence was calculated for first ever completed ischemic stroke. Poisson regression models were used to calculate adjusted ischemic stroke rates, rate ratios, and trends. Results There were 2,604 ischemic strokes in Mexican Americans and 2,042 in non-Hispanic whites. The rate ratios (Mexican American:non-Hispanic white) were 1.94 (95% confidence interval [CI] = 1.67–2.25), 1.50 (95% CI = 1.35– 1.67), and 1.00 (95% CI = 0.90–1.11) among those aged 45 to 59, 60 to 74, and 75 years and older, respectively, and 1.34 (95% CI = 1.23–1.46) when adjusted for age. Ischemic stroke incidence declined during the study period by 35.9% (95% CI = 25.9–44.5). The decline was limited to those aged ?60 years, and happened in both ethnic groups similarly (p > 0.10), implying that the disparities seen in the 45- to 74-year age group persist unabated. Interpretation Ischemic stroke incidence rates have declined dramatically in the past decade in both ethnic groups for those aged ?60 years. However, the disparity between Mexican American and non-Hispanic white stroke rates persists in those <75 years of age. Although the decline in stroke is encouraging, additional prevention efforts targeting young Mexican Americans are warranted. PMID:23868398

  17. An M-step preconditioned conjugate gradient method for parallel computation

    NASA Technical Reports Server (NTRS)

    Adams, L.

    1983-01-01

    This paper describes a preconditioned conjugate gradient method that can be effectively implemented on both vector machines and parallel arrays to solve sparse symmetric and positive definite systems of linear equations. The implementation on the CYBER 203/205 and on the Finite Element Machine is discussed and results obtained using the method on these machines are given.

  18. Professors' and Trainees' Perceptions of Educational Quality as Related to Preconditions of Deep Learning in "Musikdidaktik"

    ERIC Educational Resources Information Center

    Ferm, Cecilia; Johansen, Geir

    2008-01-01

    Interview-based case studies, involving two institutions, four professors and 11 music teacher trainees were conducted in order to investigate the preconditions for deep learning in the subject of higher music education called "musikdidaktik". Analysis was based on the "didaktiktriangle" which is a theoretical model that…

  19. Progress Toward a Stabilization and Preconditioning Protocol for Polycrystalline Thin-Film Photovoltaic Modules

    SciTech Connect

    del Cueto, J. A.; Deline, C. A.; Rummel, S. R.; Anderberg, A.

    2010-08-01

    Cadmium telluride (CdTe) and copper indium gallium diselenide (CIGS) thin-film photovoltaic (PV) modules can exhibit substantial variation in measured performance depending on prior exposure history. This study examines the metastable performance changes in these PV modules with the goal of establishing standard preconditioning or stabilization exposure procedures to mitigate measured variations prior to current-voltage (IV) measurements.

  20. An anisotropic preconditioning for the Wilson fermion matrix on the lattice

    SciTech Connect

    Balint Joo, Robert G. Edwards, Michael J. Peardon

    2010-01-01

    A preconditioning for the Wilson fermion matrix on the lattice is defined which is particularly suited to the case when the temporal lattice spacing is much smaller than the spatial one. Details on the implementation of the scheme are given. The method is tested in numerical studies of QCD on anisotropic lattices.

  1. 40 CFR 92.125 - Pre-test procedures and preconditioning.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... required. Couple the engine to the dynamometer or locomotive alternator/generator. (4) Start cooling system... test is aborted, the converter must pass the efficiency check described in § 92.121 prior to starting... preconditioning. 92.125 Section 92.125 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)...

  2. 40 CFR 92.125 - Pre-test procedures and preconditioning.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... required. Couple the engine to the dynamometer or locomotive alternator/generator. (4) Start cooling system... test is aborted, the converter must pass the efficiency check described in § 92.121 prior to starting... preconditioning. 92.125 Section 92.125 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)...

  3. Evaluation of High-intensity and Low-intensity Preconditioning Systems 

    E-print Network

    Orsak, Andrew Nathan

    2012-02-14

    Steer calves n = 345 (year 1 n = 183; 253 ± 35 kg, year 2 n = 162; 241 ± 36 kg initial BW) were used to evaluate 56-d preconditioning systems in each of two years. Angus- and Charolais-sired calves out of crossbred dams ...

  4. Dynamic Inference of Likely Data Preconditions over Predicates by Tree Learning

    E-print Network

    Chauduri, Swarat

    Sankaranarayanan NEC Laboratories America. srirams@nec-labs.com Swarat Chaudhuri Penn. State University swarat@cse.psu.edu Franjo Ivanci´c NEC Laboratories America. ivancic@nec-labs.com Aarti Gupta NEC Laboratories America. agupta@nec-labs.com ABSTRACT We present a technique to infer likely data preconditions for procedures

  5. 40 CFR 86.153-98 - Vehicle and canister preconditioning; refueling test.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 19 2014-07-01 2014-07-01 false Vehicle and canister preconditioning; refueling test. 86.153-98 Section 86.153-98 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1977 and...

  6. 40 CFR 1065.590 - PM sampling media (e.g., filters) preconditioning and tare weighing.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false PM sampling media (e.g., filters... Specified Duty Cycles § 1065.590 PM sampling media (e.g., filters) preconditioning and tare weighing. Before an emission test, take the following steps to prepare PM sampling media (e.g., filters) and...

  7. 40 CFR 1065.590 - PM sampling media (e.g., filters) preconditioning and tare weighing.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false PM sampling media (e.g., filters... Specified Duty Cycles § 1065.590 PM sampling media (e.g., filters) preconditioning and tare weighing. Before an emission test, take the following steps to prepare PM sampling media (e.g., filters) and...

  8. 40 CFR 1065.590 - PM sampling media (e.g., filters) preconditioning and tare weighing.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false PM sampling media (e.g., filters... Specified Duty Cycles § 1065.590 PM sampling media (e.g., filters) preconditioning and tare weighing. Before an emission test, take the following steps to prepare PM sampling media (e.g., filters) and...

  9. 40 CFR 1065.590 - PM sampling media (e.g., filters) preconditioning and tare weighing.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 33 2011-07-01 2011-07-01 false PM sampling media (e.g., filters... Specified Duty Cycles § 1065.590 PM sampling media (e.g., filters) preconditioning and tare weighing. Before an emission test, take the following steps to prepare PM sampling media (e.g., filters) and...

  10. 40 CFR 1065.590 - PM sampling media (e.g., filters) preconditioning and tare weighing.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false PM sampling media (e.g., filters... Specified Duty Cycles § 1065.590 PM sampling media (e.g., filters) preconditioning and tare weighing. Before an emission test, take the following steps to prepare PM sampling media (e.g., filters) and...

  11. 40 CFR 85.2218 - Preconditioned idle test-EPA 91.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 19 2012-07-01 2012-07-01 false Preconditioned idle test-EPA 91. 85.2218 Section 85.2218 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM MOBILE SOURCES Emission Control System Performance Warranty...

  12. 40 CFR 85.2219 - Idle test with loaded preconditioning-EPA 91.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 19 2012-07-01 2012-07-01 false Idle test with loaded preconditioning-EPA 91. 85.2219 Section 85.2219 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM MOBILE SOURCES Emission Control...

  13. 40 CFR 85.2220 - Preconditioned two speed idle test-EPA 91.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 19 2012-07-01 2012-07-01 false Preconditioned two speed idle test-EPA 91. 85.2220 Section 85.2220 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM MOBILE SOURCES Emission Control System...

  14. The Role of Macrophage Migration Inhibitory Factor in Anesthetic-Induced Myocardial Preconditioning

    PubMed Central

    Rossaint, Rolf; Bleilevens, Christian; Dollo, Florian; Siry, Laura; Rajabi-Alampour, Setareh; Beckers, Christian; Soppert, Josefin; Lue, Hongqi; Rex, Steffen; Bernhagen, Jürgen; Stoppe, Christian

    2014-01-01

    Introduction Anesthetic-induced preconditioning (AIP) is known to elicit cardioprotective effects that are mediated at least in part by activation of the kinases AMPK and PKC? as well as by inhibition of JNK. Recent data demonstrated that the pleiotropic cytokine macrophage migration inhibitory factor (MIF) provides cardioprotection through activation and/or inhibition of kinases that are also known to mediate effects of AIP. Therefore, we hypothesized that MIF could play a key role in the AIP response. Methods Cardiomyocytes were isolated from rats and subjected to isoflurane preconditioning (4 h; 1.5 vol. %). Subsequently, MIF secretion and alterations in the activation levels of protective kinases were compared to a control group that was exposed to ambient air conditions. MIF secretion was quantified by ELISA and AIP-induced activation of protein kinases was assessed by Western blotting of cardiomyocyte lysates after isoflurane treatment. Results In cardiomyocytes, preconditioning with isoflurane resulted in a significantly elevated secretion of MIF that followed a biphasic behavior (30 min vs. baseline: p?=?0.020; 24 h vs. baseline p?=?0.000). Moreover, quantitative polymerase chain reaction demonstrated a significant increase in MIF mRNA expression 8 h after AIP. Of note, activation of AMPK and PKC? coincided with the observed peaks in MIF secretion and differed significantly from baseline. Conclusions These results suggest that the pleiotropic mediator MIF is involved in anesthetic-induced preconditioning of cardiomyocytes through stimulation of the protective kinases AMPK and PKC?. PMID:24667295

  15. WAVEFORM PRECONDITIONING FOR CLUTTER REJECTION IN MULTIPATH FOR SPARSE DISTRIBUTED APERTURES

    E-print Network

    Yazici, Birsen

    WAVEFORM PRECONDITIONING FOR CLUTTER REJECTION IN MULTIPATH FOR SPARSE DISTRIBUTED APERTURES T that is shaped in a desired manner. In our ing, distributed aperture, sparse aperture, waveform design, case to the Wefruaeteposin ofadraafom n waveforms beforetransmi ssi. then work pies topsysthe arbitrary distribution

  16. NLR-TR-2008-282 Multigrid acceleration of a preconditioned Krylov

    E-print Network

    Vuik, Kees

    sparse systems Iterative methods Algebraic multigrid Preconditioning Problem area Radar cross section report Unclassi ed Date June 2008 Knowledge area(s) Numerical Mathematics Descriptor(s) Radar RCS Large prediction methods are used to analyze the radar signature of military plat- forms when the radar signature

  17. Parallel Multistep Successive Sparse Approximate Inverse Preconditioning Strategies of General Sparse Matrices \\Lambda

    E-print Network

    a large sparse linear sytem Ax = b; (1) where A is a nonsingular general matrix of order n. A sparse approximate inverse preconditioning technique is first to find a sparse matrix M which is a good approximation of the original matrix. Thus, instead of computing a costly high ac­ curacy sparse approximate inverse

  18. Analysis of Off-Board Powered Thermal Preconditioning in Electric Drive Vehicles: Preprint

    SciTech Connect

    Barnitt, R. A.; Brooker, A. D.; Ramroth, L.; Rugh , J.; Smith, K. A.

    2010-12-01

    Following a hot or cold thermal soak, vehicle climate control systems (air conditioning or heat) are required to quickly attain a cabin temperature comfortable to the vehicle occupants. In a plug-in hybrid electric or electric vehicle (PEV) equipped with electric climate control systems, the traction battery is the sole on-board power source. Depleting the battery for immediate climate control results in reduced charge-depleting (CD) range and additional battery wear. PEV cabin and battery thermal preconditioning using off-board power supplied by the grid or a building can mitigate the impacts of climate control. This analysis shows that climate control loads can reduce CD range up to 35%. However, cabin thermal preconditioning can increase CD range up to 19% when compared to no thermal preconditioning. In addition, this analysis shows that while battery capacity loss over time is driven by ambient temperature rather than climate control loads, concurrent battery thermal preconditioning can reduce capacity loss up to 7% by reducing pack temperature in a high ambient temperature scenario.

  19. PRECONDITIONING FOR THE p-VERSION BOUNDARY ELEMENT METHOD IN THREE DIMENSIONS WITH

    E-print Network

    Guo, Benqi

    parti- tion with triangular elements is one of the most popular choices in practice, and an analysis decompositions have been developed and applied widely for the finite element methods. For boundary elementPRECONDITIONING FOR THE p-VERSION BOUNDARY ELEMENT METHOD IN THREE DIMENSIONS WITH TRIANGULAR

  20. Preconditioned iterative methods for nonselfadjoint or indefinite elliptic boundary value problems

    SciTech Connect

    Bramble, J.H.; Pasciak, J.E.

    1984-01-01

    We consider a Galerkin-Finite Element approximation to a general linear elliptic boundary value problem which may be nonselfadjoint or indefinite. We show how to precondition the equations so that the resulting systems of linear algebraic equations lead to iteration procedures whose iterative convergence rates are independent of the number of unknowns in the solution.

  1. C. Canuto, P. Gervasio, A. Quarteroni Finite-Element Preconditioning of G-NI Spectral Methods

    E-print Network

    Ceragioli, Francesca

    C. Canuto, P. Gervasio, A. Quarteroni Finite-Element Preconditioning of G-NI Spectral Methods ABSTRACT Several old and new finite-element preconditioners for nodal-based spectral discretiza- tions, Quarteroni, Zang 2006), as well as that of more general spectral-element methods in which the preconditioners

  2. TWOLEVEL DOMAIN DECOMPOSITION PRECONDITIONING FOR THE pVERSION FINITE ELEMENT METHOD

    E-print Network

    Mandel, Jan

    TWO­LEVEL DOMAIN DECOMPOSITION PRECONDITIONING FOR THE p­VERSION FINITE ELEMENT METHOD IN THREE stiffness matrices only. The method is applied to the p­version finite element method for three to the p­version finite element method for the elasticity problem, which yields a natural, discretization

  3. Does intraperitoneal medical ozone preconditioning and treatment ameliorate the methotrexate induced nephrotoxicity in rats?

    PubMed Central

    Aslaner, Arif; Çak?r, Tu?rul; Çelik, Betül; Do?an, U?ur; Mayir, Burhan; Akyüz, Cebrail; Polat, Cemal; Ba?türk, Ahmet; Soyer, Vural; Koç, Süleyman; ?ehirli, Ahmet Özer

    2015-01-01

    Methotrexate is a chemotherapeutic agent used for many cancer treatments. It leads to toxicity with its oxidative injury. The purpose of our study is investigating the medical ozone preconditioning and treatment has any effect on the methotrexate-induced kidneys by activating antioxidant enzymes in rats. Eighteen rats were divided into three equal groups; control, Mtx without and with medical ozone. Nephrotoxicity was performed with a single dose of 20 mg/kg Mtx intraperitoneally at the fifteenth day of experiment on groups 2 and 3. Medical ozone preconditioning was performed at a dose of 25 mcg/ml (5 ml) intraperitoneally everyday in the group 3 and treated with medical ozone for five more days while group 2 was received only 5 ml of saline everyday for twenty days. All rats were sacrificed at the end of third week and the blood and kidney tissue samples were obtained to measure the levels of TNF-?, IL-1?, malondialdehyde, glutathione and myeloperoxidase. Kidney injury score was evaluated histolopatologically. Medical ozone preconditioning and treatment ameliorated the biochemical parameters and kidney injury induced by Mtx. There was significant increase in tissue MDA, MPO activity, TNF-? and IL-1? (P<0.05) and significant decrease in tissue GSH and histopathology (P<0.05) after Mtx administration. The preconditioning and treatment with medical ozone ameliorated the nephrotoxicity induced by Mtx in rats by activating antioxidant enzymes and prevented renal tissue. PMID:26550330

  4. Hypoxic preconditioning decreases nuclear factor ?B activity via Disrupted in Schizophrenia-1.

    PubMed

    Liu, Jia-Ren; Liu, Qian; Khoury, Joseph; Li, Yue-Jin; Han, Xiao-Hui; Li, Jing; Ibla, Juan C

    2016-01-01

    Nuclear factor ?B is a key mediator of inflammation during conditions of hypoxia. Here, we used models of hypoxic pre-conditioning as mechanism to decrease nuclear factor ?B activity induced by hypoxia. Our initial studies suggested that Disrupted in Schizophrenia-1 may be induced by hypoxic pre-conditioning and possibly involved in the regulation of nuclear factor ?B. In this study we used Disrupted in Schizophrenia-1 exogenous over-expression and knock-down to determine its effect on ataxia telangiectasia mutated - nuclear factor ?B activation cascade. Our results demonstrated that hypoxic pre-conditioning significantly increased the expression of Disrupted in Schizophrenia-1 at mRNA and protein levels both in vitro and in vivo. Over-expression of Disrupted in Schizophrenia-1 significantly attenuated the hypoxia-mediated ataxia telangiectasia mutated phosphorylation and prevented its cytoplasm translocation where it functions to activate nuclear factor ?B. We further determined that Disrupted in Schizophrenia-1 activated the protein phosphatase 2A, preventing the phosphorylation of ataxia telangiectasia mutated serine-1981, the main regulatory site of ataxia telangiectasia mutated activity. Cellular levels of Disrupted in Schizophrenia-1 protein significantly decreased nuclear factor ?B activation profiles and pro-inflammatory gene expression. Taken together, these results demonstrate that hypoxic pre-conditioning decreases the activation of nuclear factor ?B through the transcriptional induction of Disrupted in Schizophrenia-1. PMID:26615762

  5. Resistivitet-och IP-mtningar vid sp Hard

    E-print Network

    1 Resistivitet- och IP- mätningar vid �spö Hard Rock Laboratory Erik Fennvik Examensarbeten i universitet 2015 #12;2 #12;3 Resistivitet- och IP-mätningar vid �spö Hard Rock Laboratory Kandidatarbete Erik-mätningar vid �spö Hard Rock Laboratory ERIK FENNVIK Fennvik, E., 2015: Resistivitet­ och IP-mätningar vid �spö

  6. Using IPS Magnetic Modeling to Determine Bz

    NASA Astrophysics Data System (ADS)

    Jackson, B. V.; Yu, H. S.; Hick, P. P.; Buffington, A.; Mejia-Ambriz, J. C.; Bisi, M. M.; Tokumaru, M.

    2014-12-01

    Interplanetary scintillation (IPS) observations enable remote determinations of velocity and density in the inner heliosphere while also providing forecasts of these quantities. Using the global velocities inferred from IPS, and through convection upward of magnetic fields perpendicular to a source surface produced by the Current-Sheet Source Surface (CSSS) modified potential model (Zhao and Hoeksema, J. Geophys. Res., 100, 19, 1995), global long-duration radial and tangential heliospheric field components can also be determined. In order to better include short-term transient effects and derive a value for the field normal to these components (Bn) during periods where CMEs, are present, we have tested an extension to our current 3D vector-field analysis. This extension adds closed fields from below the source surface to the CSSS model values, and when traced outward from the sub-Earth point, three magnetic field components are present. These are compared to in-situ magnetic fields measured near Earth for several periods throughout the current solar cycle from the minimum between Solar Cycle 23 and 24 up until the present. We find a significant positive correlation when using this extension to current analyses including that of the Bn field for the test cases analyzed thus far.

  7. Live Video and IP-TV

    NASA Astrophysics Data System (ADS)

    Merani, Maria Luisa; Saladino, Daniela

    This Chapter aims at providing a comprehensive insight into the most recent advances in the field of P2P architectures for video broadcasting, focusing on live video streaming P2P live video streaming . After introducing a classification of P2P video solutions, the first part of the Chapter provides an overview of the most interesting P2P IP-TV P2P IP-TV systems currently available over the Internet. It also concentrates on the process of data diffusion within the P2P overlay and complements this view with some measurements that highlight the most salient features of P2P architectures. The second part of the Chapter completes the view, bringing up the modeling efforts to capture the main characteristics and limits of P2P streaming systems, both analytically and numerically. The Chapter is closed by a pristine look at some challenging, open questions, with a specific emphasis on the adoption of network coding in P2P streaming solutions.

  8. Sustained signalling by PTH modulates IP3 accumulation and IP3 receptors through cyclic AMP junctions

    PubMed Central

    Meena, Abha; Tovey, Stephen C.; Taylor, Colin W.

    2015-01-01

    ABSTRACT Parathyroid hormone (PTH) stimulates adenylyl cyclase through type 1 PTH receptors (PTH1R) and potentiates the Ca2+ signals evoked by carbachol, which stimulates formation of inositol 1,4,5-trisphosphate (IP3). We confirmed that in HEK cells expressing PTH1R, acute stimulation with PTH(1-34) potentiated carbachol-evoked Ca2+ release. This was mediated by locally delivered cyclic AMP (cAMP), but unaffected by inhibition of protein kinase A (PKA), exchange proteins activated by cAMP, cAMP phosphodiesterases (PDEs) or substantial inhibition of adenylyl cyclase. Sustained stimulation with PTH(1-34) causes internalization of PTH1R–adenylyl cyclase signalling complexes, but the consequences for delivery of cAMP to IP3R within cAMP signalling junctions are unknown. Here, we show that sustained stimulation with PTH(1-34) or with PTH analogues that do not evoke receptor internalization reduced the potentiated Ca2+ signals and attenuated carbachol-evoked increases in cytosolic IP3. Similar results were obtained after sustained stimulation with NKH477 to directly activate adenylyl cyclase, or with the membrane-permeant analogue of cAMP, 8-Br-cAMP. These responses were independent of PKA and unaffected by substantial inhibition of adenylyl cyclase. During prolonged stimulation with PTH(1-34), hyperactive cAMP signalling junctions, within which cAMP is delivered directly and at saturating concentrations to its targets, mediate sensitization of IP3R and a more slowly developing inhibition of IP3 accumulation. PMID:25431134

  9. Distinct iPS Cells Show Different Cardiac Differentiation Efficiency

    PubMed Central

    Yuasa, Shinsuke; Egashira, Toru; Seki, Tomohisa; Hashimoto, Hisayuki; Shimoji, Kenichiro; Kageyama, Toshimi; Tanaka, Tomofumi; Hattori, Fumiyuki; Murata, Mitsushige; Kimura, Kensuke; Fukuda, Keiichi

    2013-01-01

    Patient-specific induced pluripotent stem (iPS) cells can be generated by introducing transcription factors that are highly expressed in embryonic stem (ES) cells into somatic cells. This opens up new possibilities for cell transplantation-based regenerative medicine by overcoming the ethical issues and immunological problems associated with ES cells. Despite the development of various methods for the generation of iPS cells that have resulted in increased efficiency, safety, and general versatility, it remains unknown which types of iPS cells are suitable for clinical use. Therefore, the aims of the present study were to assess (1) the differentiation potential, time course, and efficiency of different types of iPS cell lines to differentiate into cardiomyocytes in vitro and (2) the properties of the iPS cell-derived cardiomyocytes. We found that high-quality iPS cells exhibited better cardiomyocyte differentiation in terms of the time course and efficiency of differentiation than low-quality iPS cells, which hardly ever differentiated into cardiomyocytes. Because of the different properties of the various iPS cell lines such as cardiac differentiation efficiency and potential safety hazards, newly established iPS cell lines must be characterized prior to their use in cardiac regenerative medicine. PMID:24367382

  10. Risk of Ischemic Stroke in Patients With Gastric Cancer

    PubMed Central

    Kuan, Ai-Seon; Chen, San-Chi; Yeh, Chiu-Mei; Hung, Man-Hsin; Hung, Yi-Ping; Chen, Tzeng-Ji; Liu, Chia-Jen

    2015-01-01

    Abstract Improvements in therapeutic modalities have prolonged the survival of gastric cancer patients. Comorbidities such as thromboembolic events that emerge as a result of disease complexities and/or treatments received have not been considered. The objectives of this study are to examine the relationship between gastric cancer and ischemic stroke, and to determine predictive risk factors. A nationwide population-based cohort study was conducted using data from the Taiwan National Health Insurance database. A total of 45,060 gastric cancer patients and non-cancer counterparts without antecedent stroke were recruited. Hazard ratios (HRs) and the cumulative incidence of ischemic stroke were calculated, and risk factors for ischemic stroke were assessed. Gastric cancer patients were associated with higher risk of ischemic stroke (HR 1.11, 95% confidence interval [CI] 1.03–1.19, P?=?0.007), especially in participants younger than 65 years (HR 1.61, 95% CI 1.39–1.86, P?ischemic stroke in gastric cancer patients included age, hypertension, atrial fibrillation, dyslipidemia, and having received major surgery for gastric cancer. Our findings suggest the importance of stroke surveillance and prevention strategies in high-risk patients. Having received major surgery for gastric cancer is a significant risk factor in these patients. PMID:26376378

  11. Potential microRNA biomarkers for acute ischemic stroke.

    PubMed

    Zeng, Ye; Liu, Jing-Xia; Yan, Zhi-Ping; Yao, Xing-Hong; Liu, Xiao-Heng

    2015-12-01

    Acute ischemic stroke is a significant cause of high morbidity and mortality in the aging population globally. However, current therapeutic strategies for acute ischemic stroke are limited. Atherosclerotic plaque is considered an independent risk factor for acute ischemic stroke. To identify biomarkers for carotid atheromatous plaque, bioinformatics analysis of the gene microarray data of plaque and intact tissue from individuals was performed. Differentially expressed genes (DEGs) were identified using the Multtest and Limma packages of R language, including 56 downregulated and 69 upregulated DEGs. Enriched microRNA (miRNA or miR) DEGs networks were generated using WebGestalt software and the STRING databases, and the miRNAs were validated using serum from acute ischemic stroke patients with reverse transcription quantitative PCR (RT?qPCR). Four confirmed differentially expressed miRNAs (miR?9, ?22, ?23 and ?125) were associated with 28 upregulated DEGs, and 7 miRNAs (miR?9, ?30, ?33, ?124, ?181, ?218 and ?330) were associated with 25 downregulated DEGs. Gene ontology (GO) function suggested that the confirmed miRNA?targeted DEGs predominately associated with signal transduction, the circulatory system, biological adhesion, striated muscle contraction, wound healing and the immune system. The confirmed miRNA?targeted genes identified serve as potential therapeutic targets for acute ischemic stroke. PMID:26459744

  12. Lessons Learned in the Design and Use of IP1 / IP2 Flexible Packaging - 13621

    SciTech Connect

    Sanchez, Mike; Reeves, Wendall; Smart, Bill

    2013-07-01

    For many years in the USA, Low Level Radioactive Waste (LLW), contaminated soils and construction debris, have been transported, interim stored, and disposed of, using IP1 / IP2 metal containers. The performance of these containers has been more than adequate, with few safety occurrences. The containers are used under the regulatory oversight of the US Department of Transportation (DOT), 49 Code of Federal Regulations (CFR). In the late 90's the introduction of flexible packaging for the transport, storage, and disposal of low level contaminated soils and construction debris was introduced. The development of flexible packaging came out of a need for a more cost effective package, for the large volumes of waste generated by the decommissioning of many of the US Department of Energy (DOE) legacy sites across the US. Flexible packaging had to be designed to handle a wide array of waste streams, including soil, gravel, construction debris, and fine particulate dust migration. The design also had to meet all of the IP1 requirements under 49CFR 173.410, and be robust enough to pass the IP2 testing 49 CFR 173.465 required for many LLW shipments. Tens of thousands of flexible packages have been safely deployed and used across the US nuclear industry as well as for hazardous non-radioactive applications, with no recorded release of radioactive materials. To ensure that flexible packages are designed properly, the manufacturer must use lessons learned over the years, and the tests performed to provide evidence that these packages are suitable for transporting low level radioactive wastes. The design and testing of flexible packaging for LLW, VLLW and other hazardous waste streams must be as strict and stringent as the design and testing of metal containers. The design should take into consideration the materials being loaded into the package, and should incorporate the right materials, and manufacturing methods, to provide a quality, safe product. Flexible packaging can be shown to meet the criteria for safe and fit for purpose packaging, by meeting the US DOT regulations, and the IAEA Standards for IP-1 and IP-2 including leak tightness. (authors)

  13. A Measurement-based Deployment Proposal for IP Anycast Hitesh Ballani

    E-print Network

    Ratnasamy, Sylvia

    evaluation of the behavior of IP Anycast under fail- ure. We find that: (1) IP Anycast, if deployed in an adA Measurement-based Deployment Proposal for IP Anycast Hitesh Ballani Cornell University Ithaca, NY infrastructure services, the performance of IP(v4) Anycast and its interaction with IP routing practices

  14. A Measurement-based Deployment Proposal for IP Anycast Hitesh Ballani, Paul Francis, Sylvia Ratnasamy

    E-print Network

    Francis, Paul

    and the first evaluation of the behavior of IP Anycast under failure. We find that: (1) IP Anycast, if deployed1 A Measurement-based Deployment Proposal for IP Anycast Hitesh Ballani, Paul Francis, Sylvia use in critical infrastructure services, the performance of IP(v4) Anycast and its interaction with IP

  15. REPORT PREPARED FOR THE WELSH ASSEMBLY GOVERNMENT IP CRIME & E CRIME

    E-print Network

    Harman, Neal.A.

    1 REPORT PREPARED FOR THE WELSH ASSEMBLY GOVERNMENT ON IP CRIME & E CRIME Presented by IP Wales. IP CRIME page 23 5. E COMMERCE LAW page 30 6. E CRIME page 38 7. RELEVANCE FOR WELSH SMEs page 45 8. CONCLUSION page 49 APPENDICES (Supplied under separate cover) IP CRIME (a) UK Counter Offensive an IP Crime

  16. Specifications for End to End IP Rate Control (Version 1.0)

    E-print Network

    New South Wales, University of

    Probe MessageIP Data Packet Core Routers Edge Router IP Network #12;4 2 IP host The primary role of IPSpecifications for End to End IP Rate Control (Version 1.0) Abdul Aziz Mustafa, Mahbub Hassan exists in the IP-based networks. In a recent paper [1], we proposed a network-level flow control

  17. Analysis of a Mathematical Model of Ischemic Cutaneous wounds

    E-print Network

    Friedman, Avner; Xue, Chuan

    2009-01-01

    Chronic wounds represent a major public health problem affecting 6.5 million people in the United States. Ischemia represents a serious complicating factor in wound healing. In this paper we analyze a recently developed mathematical model of ischemic dermal wounds. The model consists of a coupled system of partial differential equations in the partially healed region, with the wound boundary as a free boundary. The extracellular matrix (ECM) is assumed to be viscoelastic, and the free boundary moves with the velocity of the ECM at the boundary of the open wound. The model equations involve the concentrations of oxygen, cytokines, and the densities of several types of cells. The ischemic level is represented by a parameter which appears in the boundary conditions, 0 <= gamma < 1; gamma near 1 corresponds to extreme ischemia and gamma = 0 corresponds to normal non-ischemic conditions. We establish global existence and uniqueness of the free boundary problem and study the dependence of the free boundary on...

  18. Telemetry and Communication IP Video Player

    NASA Technical Reports Server (NTRS)

    OFarrell, Zachary L.

    2011-01-01

    Aegis Video Player is the name of the video over IP system for the Telemetry and Communications group of the Launch Services Program. Aegis' purpose is to display video streamed over a network connection to be viewed during launches. To accomplish this task, a VLC ActiveX plug-in was used in C# to provide the basic capabilities of video streaming. The program was then customized to be used during launches. The VLC plug-in can be configured programmatically to display a single stream, but for this project multiple streams needed to be accessed. To accomplish this, an easy to use, informative menu system was added to the program to enable users to quickly switch between videos. Other features were added to make the player more useful, such as watching multiple videos and watching a video in full screen.

  19. Mmp-9 inhibition: a therapeutic strategy in ischemic stroke.

    PubMed

    Chaturvedi, Mayank; Kaczmarek, Leszek

    2014-02-01

    Ischemic stroke is a leading cause of disability worldwide. In cerebral ischemia there is an enhanced expression of matrix metallo-proteinase-9 (MMP-9), which has been associated with various complications including excitotoxicity, neuronal damage, apoptosis, blood-brain barrier (BBB) opening leading to cerebral edema, and hemorrhagic transformation. Moreover, the tissue plasminogen activator (tPA), which is the only US-FDA approved treatment of ischemic stroke, has a brief 3 to 4 h time window and it has been proposed that detrimental effects of tPA beyond the 3 h since the onset of stroke are derived from its ability to activate MMP-9 that in turn contributes to the breakdown of BBB. Therefore, the available literature suggests that MMP-9 inhibition can be of therapeutic importance in ischemic stroke. Hence, combination therapies of MMP-9 inhibitor along with tPA can be beneficial in ischemic stroke. In this review we will discuss the current status of various strategies which have shown neuroprotection and extension of thrombolytic window by directly or indirectly inhibiting MMP-9 activity. In the introductory part of the review, we briefly provide an overview on ischemic stroke, commonly used models of ischemic stroke and a role of MMP-9 in ischemia. In next part, the literature is organized as various approaches which have proven neuroprotective effects through direct or indirect decrease in MMP-9 activity, namely, using biotherapeutics, involving MMP-9 gene inhibition using viral vectors; using endogenous inhibitor of MMP-9, repurposing of old drugs such as minocycline, new chemical entities like DP-b99, and finally other approaches like therapeutic hypothermia. PMID:24026771

  20. Vitamin D status, hypertension and ischemic stroke: a clinical perspective.

    PubMed

    Majumdar, V; Prabhakar, P; Kulkarni, G B; Christopher, R

    2015-11-01

    The relationship between vitamin D deficiency and stroke was cross-sectionally evaluated in the high-risk Asian Indian population. Age- and gender-matched, 239 ischemic stroke patients and 241 control subjects were recruited. Vitamin D status was estimated by measuring serum 25-hydroxyvitamin D (25(OH)D) levels. After multivariate adjustment for a range of potential covariates in a logistic regression model, an inverse association was found between serum 25(OH)D concentration and risk of ischemic stroke: subjects with severely low 25(OH)D levels (?9.33?ng?ml(-1)) were found to be at 3.13-fold (95% confidence interval (CI), (1.22-8.07)) increased risk of ischemic stroke as compared with those with high levels. Adjustment for systolic blood pressure levels was found to abrogate this association (odds ratio (OR)=2.00, 95% CI=0.61-6.50). On stratification, a pronounced association was found between low 25(OH)D and risk of ischemic stroke in hypertensives, OR=13.54, 95% CI=1.94-94.43 as compared with no association in non-hypertensives, (Pinteraction=0.04). We conclude that high blood pressure partly explains the association between 25(OH)D levels and ischemic stroke. Presence of hypertension amply aggravates the risk of ischemic stroke associated with low vitamin D levels. Meticulous management of hypertension, regular monitoring of serum 25(OH)D levels and treatment of severe vitamin D deficiency, particularly in hypertensive subjects, could help in effective prevention of stroke. PMID:25810064

  1. Characterizing Human Effort in Wireless Voice Over IP

    E-print Network

    New South Wales, University of

    ;Abstract Skype Voice Over IP (VoIP) traces from an experimental WiFi network were analyzed to detect for calls that are going to face premature ending by simply monitoring the number of times the user has put telephone (PSTN) networks. If there are link quality issues, for example a link experiencing interference

  2. Provisioning IP Backbone Networks to Support Latency Sensitive Traffic

    E-print Network

    Tobagi, Fouad

    collected from the Sprint IP network. We then develop a procedure which uses this model to find the amountProvisioning IP Backbone Networks to Support Latency Sensitive Traffic Chuck Fraleigh and Fouad this procedure to the Sprint network, we find that satisfying end-to-end delay requirements as low as 3 ms

  3. IR4IP Tutorial IPI Confex, March 2009

    E-print Network

    Roelleke, Thomas

    IR4IP Tutorial IPI Confex, March 2009 Erik Graf and Thomas Roelleke 1 / 18 Introduction IPI Confex, March 2009 Thomas Roelleke Queen Mary University of London 2 / 18 Outline 1 Structure of IR4IP Tutorial 2 Topics, Issues, and "Problems" in IR 3 Foundations 4 Historical Notes 5 Web or Enterprise Search

  4. Identifying and Tracking Suspicious Activities through IP Gray Space Analysis

    E-print Network

    Zhang, Zhi-Li

    the address blocks of such networks. Using one-month traffic data collected in a large campus network, we have to extract the IP gray space in our campus network. Subsequently, we analyze the behavioral patterns Security Keywords IP Gray Space, profiling, network traffic analysis, entropy, anomaly detection 1

  5. iPS cells: mapping the policy issues.

    PubMed

    Zarzeczny, Amy; Scott, Christopher; Hyun, Insoo; Bennett, Jami; Chandler, Jennifer; Chargé, Sophie; Heine, Heather; Isasi, Rosario; Kato, Kazuto; Lovell-Badge, Robin; McNagny, Kelly; Pei, Duanqing; Rossant, Janet; Surani, Azim; Taylor, Patrick L; Ogbogu, Ubaka; Caulfield, Timothy

    2009-12-11

    Given the explosion of research on induced pluripotent stem (iPS) cells, it is timely to consider the various ethical, legal, and social issues engaged by this fast-moving field. Here, we review issues associated with the procurement, basic research, and clinical translation of iPS cells. PMID:20005794

  6. VoIP Deployment Committee Version 1.6

    E-print Network

    Texas at Austin, University of

    to VoIP was endorsed by SITAB in March of 2012: · Acquire a new standards-based Enterprise Class VoIP telephone system ($2m in ITS Capital Budget). · Distribute operational and cost responsibilities for the telephone system between units and ITS; completing the transition by 2016. · Manage the transition: 1

  7. IP core design of template matching algorithm in image processing

    NASA Astrophysics Data System (ADS)

    Zhu, Quanqing; Zou, Xuecheng; Dong, Zhenzhong; Huang, Feng; Shen, Xubang

    2001-09-01

    This paper presents the design and implementation of template matching IP cores for image processing. Enhanced Moment Preserving Pattern Matching (MPPM) algorithm of template matching was adopted for efficient hardware implementation. The cores were coded in Verilog HDL for modularity and portability. The IP cores were validated in a XC4052XL FPGA and XESS XS40 prototyping board.

  8. Enabling Secure IP Telephony in Enterprise Networks BRENNEN EMERICK REYNOLDS

    E-print Network

    Yoo, S. J. Ben

    Enabling Secure IP Telephony in Enterprise Networks By BRENNEN EMERICK REYNOLDS B.S. (University OF CALIFORNIA DAVIS Approved: Committee in charge 2002 ­i­ #12;Enabling Secure IP Telephony in Enterprise Telephony Over Converged Networks 7 2.1 Converged Network Architecture

  9. Quick Start Guide Cisco Small Business Pro IP Phone

    E-print Network

    Cerveny, Vlastislav

    phone to create a wireless connection between the phone and the network. See the WBP54G documentationQuick Start Guide Cisco Small Business Pro IP Phone Models SPA501G, SPA502G, SPA504G, SPA508G, and SPA509G Package Contents · IP Telephone · Phone Stand · RJ-45 Ethernet Cable · Quick Start Guide

  10. Security Challenges in the IP-based Internet of Things

    E-print Network

    Security Challenges in the IP-based Internet of Things Tobias Heer , Oscar Garcia-Morchon , Ren of standard IP security protocols. Keywords: Security, Internet of Things, IETF 1 Introduction The Internet.garcia,sye.loong.keoh,sandeep.kumar}@philips.com Abstract. A direct interpretation of the term Internet of Things refers to the use of standard Internet

  11. The IPS Compiler: Optimizations, Variants and Concrete Efficiency

    E-print Network

    International Association for Cryptologic Research (IACR)

    The IPS Compiler: Optimizations, Variants and Concrete Efficiency Yehuda Lindell Eli Oxman Benny in the presence of covert adversaries. Finally, we analyze the IPS compiler from a concrete efficiency perspective. Keywords: secure computation, malicious, semi-honest and covert adversaries, asymptotic and concrete

  12. Maintaining high-quality IP audio services in lossy IP network environments

    NASA Astrophysics Data System (ADS)

    Barton, Robert J., III; Chodura, Hartmut

    2000-07-01

    In this paper we present our research activities in the area of digital audio processing and transmission. Today's available teleconference audio solutions are lacking in flexibility, robustness and fidelity. There was a need for enhancing the quality of audio for IP-based applications to guarantee optimal services under varying conditions. Multiple tests and user evaluations have shown that a reliable audio communication toolkit is essential for any teleconference application. This paper summarizes our research activities and gives an overview of developed applications. In a first step the parameters, which influence the audio quality, were evaluated. All of these parameters have to be optimized in order to result into the best achievable quality. Therefore it was necessary to enhance existing schemes or develop new methods. Applications were developed for Internet-Telephony, broadcast of live music and spatial audio for Virtual Reality environments. This paper describes these applications and issues of delivering high quality digital audio services over lossy IP networks.

  13. Personalized approach to primary and secondary prevention of ischemic stroke

    PubMed Central

    2014-01-01

    Primary and secondary prevention of ischemic stroke represents a significant part of stroke management and health care. Although there are official guidelines concerning stroke management, new knowledge are introduced to them with a slight delay. This article provides an overview of current information on primary and secondary prevention of ischemic stroke. It summarizes information especially in the field of cardioembolic stroke, the use of new anticoagulants and the management of carotid stenosis based on the results of recent clinical studies. The optimal approach in stroke management is to follow these recommendations, to know new strategies and to apply an individual personalized approach in our clinical decisions. PMID:24949113

  14. Factoring in Factor VIII With Acute Ischemic Stroke.

    PubMed

    Siegler, James E; Samai, Alyana; Albright, Karen C; Boehme, Amelia K; Martin-Schild, Sheryl

    2015-10-01

    There is growing research interest into the etiologies of cryptogenic stroke, in particular as it relates to hypercoagulable states. An elevation in serum levels of the procoagulant factor VIII is recognized as one such culprit of occult cerebral infarctions. It is the objective of the present review to summarize the molecular role of factor VIII in thrombogenesis and its clinical use in the diagnosis and prognosis of acute ischemic stroke. We also discuss the utility of screening for serum factor VIII levels among patients at risk for, or those who have experienced, ischemic stroke. PMID:25669199

  15. [Dynamics of ischemic skeletal soleus muscle contraction in rats].

    PubMed

    Khoma, O M; Zavodovs'ky?, D A; Nozdrenko, D N; Dolhopolov, O V; Miroshnychenko, M S; Motuziuk, O P

    2014-01-01

    The processes of change in the rate of generation of power response of artificially ischemic muscle using frequency modulated electrical efferent stimulation were investigated. A strain-gauge technique for registration of contraction process was used. Ischemia was induced by ligating main blood vessels of lower extremity. It is shown that ischemia causes a decrease in muscle performance and reduces maximum frequency of the stimulus signal, which leads to the titanic contraction level. It is shown that the lowering of ischemic muscle strength and reduction of the time that needed to establish a steady state depended on the time of discharge segment in stimulation pattern. PMID:24809172

  16. Audio CAPTCHA for SIP-Based VoIP

    NASA Astrophysics Data System (ADS)

    Soupionis, Yannis; Tountas, George; Gritzalis, Dimitris

    Voice over IP (VoIP) introduces new ways of communication, while utilizing existing data networks to provide inexpensive voice communications worldwide as a promising alternative to the traditional PSTN telephony. SPam over Internet Telephony (SPIT) is one potential source of future annoyance in VoIP. A common way to launch a SPIT attack is the use of an automated procedure (bot), which generates calls and produces audio advertisements. In this paper, our goal is to design appropriate CAPTCHA to fight such bots. We focus on and develop audio CAPTCHA, as the audio format is more suitable for VoIP environments and we implement it in a SIP-based VoIP environment. Furthermore, we suggest and evaluate the specific attributes that audio CAPTCHA should incorporate in order to be effective, and test it against an open source bot implementation.

  17. Defining bacterial regulons using ChIP-seq.

    PubMed

    Myers, Kevin S; Park, Dan M; Beauchene, Nicole A; Kiley, Patricia J

    2015-09-15

    Chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) is a powerful method that identifies protein-DNA binding sites in vivo. Recent studies have illustrated the value of ChIP-seq in studying transcription factor binding in various bacterial species under a variety of growth conditions. These results show that in addition to identifying binding sites, correlation of ChIP-seq data with expression data can reveal important information about bacterial regulons and regulatory networks. In this chapter, we provide an overview of the current state of knowledge about ChIP-seq methodology in bacteria, from sample preparation to raw data analysis. We also describe visualization and various bioinformatic analyses of processed ChIP-seq data. PMID:26032817

  18. A highly efficient and effective motif discovery method for ChIP-seq/ChIP-chip data using positional information

    E-print Network

    Serfling, Robert

    the other hand, modeling and discovery of DNA motifs from a set of DNA sequences have been a major research to discover DNA motifs. Using positional preference for DNA motif discovery was most recently revisitedA highly efficient and effective motif discovery method for ChIP-seq/ChIP-chip data using

  19. Preconditioning Human Mesenchymal Stem Cells with a Low Concentration of BMP2 Stimulates Proliferation and Osteogenic Differentiation In Vitro

    PubMed Central

    Baatrup, Anette; Foldager, Casper Bindzus; Bünger, Cody

    2014-01-01

    Abstract Clinical trials using bone morphogenetic protein-2 (BMP2) for bone reconstruction have shown promising results. However, the relatively high concentration needed to be effective raises concerns for efficacy and safety. The aim of this study was to investigate the osteogenic effect of an alternative treatment strategy in which human bone marrow–derived mesenchymal stem cells (hMSCs) are preconditioned with low concentrations of BMP2 for a short time in vitro. hMSCs in suspension were stimulated for 15?min with 10 and 20?ng/mL of BMP2. After the BMP2 was removed, the cells were seeded and cultured in osteogenic medium. The effects of preconditioning were analyzed with regard to proliferation and expression of osteogenic markers at both gene and protein level. The results were compared to those from cultures with continuous BMP2 stimulation. A significant increase in proliferation was seen with both precondition and continuous stimulation with BMP2, with no difference between the treatments. Preconditioning with BMP2 significantly increased gene expression of RUNX2, COLI, ALP, and OC, and protein levels of COLI and ALP. This was not found with continuous stimulation. The role of preconditioning with BMP2 in osteogenesis was validated by findings of increased gene expression of SMAD1 and an increase in dual phosphorylation of ser 463 and ser 465 in the SMAD 1/5/8 pathway. We concluded that preconditioning hMSCs with BMP2 stimulates osteogenesis: proliferation with matrix secretion and matrix maturation of hMSCs. This implies that preconditioning with BMP2 might be more effective at inducing proliferation and osteogenic differentiation of hMSCs than continuous stimulation. Preconditioning with BMP2 could benefit the clinical application of BMP2 since side effects from high-dose treatments could be avoided. PMID:25469313

  20. On linearization and preconditioning for radiation diffusion coupled to material thermal conduction equations

    SciTech Connect

    Feng, Tao; Graduate School of China Academy Engineering Physics, Beijing 100083 ; An, Hengbin; Yu, Xijun; Li, Qin; Zhang, Rongpei

    2013-03-01

    Jacobian-free Newton–Krylov (JFNK) method is an effective algorithm for solving large scale nonlinear equations. One of the most important advantages of JFNK method is that there is no necessity to form and store the Jacobian matrix of the nonlinear system when JFNK method is employed. However, an approximation of the Jacobian is needed for the purpose of preconditioning. In this paper, JFNK method is employed to solve a class of non-equilibrium radiation diffusion coupled to material thermal conduction equations, and two preconditioners are designed by linearizing the equations in two methods. Numerical results show that the two preconditioning methods can improve the convergence behavior and efficiency of JFNK method.

  1. Parallelization of the preconditioned IDR solver for modern multicore computer systems

    NASA Astrophysics Data System (ADS)

    Bessonov, O. A.; Fedoseyev, A. I.

    2012-10-01

    This paper present the analysis, parallelization and optimization approach for the large sparse matrix solver CNSPACK for modern multicore microprocessors. CNSPACK is an advanced solver successfully used for coupled solution of stiff problems arising in multiphysics applications such as CFD, semiconductor transport, kinetic and quantum problems. It employs iterative IDR algorithm with ILU preconditioning (user chosen ILU preconditioning order). CNSPACK has been successfully used during last decade for solving problems in several application areas, including fluid dynamics and semiconductor device simulation. However, there was a dramatic change in processor architectures and computer system organization in recent years. Due to this, performance criteria and methods have been revisited, together with involving the parallelization of the solver and preconditioner using Open MP environment. Results of the successful implementation for efficient parallelization are presented for the most advances computer system (Intel Core i7-9xx or two-processor Xeon 55xx/56xx).

  2. The North Pacific High and wintertime pre-conditioning of California current productivity

    NASA Astrophysics Data System (ADS)

    Schroeder, Isaac D.; Black, Bryan A.; Sydeman, William J.; Bograd, Steven J.; Hazen, Elliott L.; Santora, Jarrod A.; Wells, Brian K.

    2013-02-01

    Abstract Variations in large-scale atmospheric forcing influence upwelling dynamics and ecosystem productivity in the California Current System (CCS). In this paper, we characterize interannual variability of the North Pacific High over 40 years and investigate how variation in its amplitude and position affect upwelling and biology. We develop a winter upwelling "<span class="hlt">pre-conditioning</span>" index and demonstrate its utility to understanding biological processes. Variation in the winter NPH can be well described by its areal extent and maximum pressure, which in turn is predictive of winter upwelling. Our winter <span class="hlt">pre-conditioning</span> index explained 64% of the variation in biological responses (fish and seabirds). Understanding characteristics of the NPH in winter is therefore critical to predicting biological responses in the CCS.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/989166','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/989166"><span id="translatedtitle">Microglial ablation and lipopolysaccharide <span class="hlt">preconditioning</span> affects pilocarpine-induced seizures in mice</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Mirrione, M.M.; Mirrione, M.M.; Konomosa, D.K.; Ioradanis, G.; Dewey, S.L.; Agzzid, A.; Heppnerd, F.L.; Tsirka, St.E.</p> <p>2010-04-01</p> <p>Activated microglia have been associated with neurodegeneration in patients and in animal models of Temporal Lobe Epilepsy (TLE), however their precise functions as neurotoxic or neuroprotective is a topic of significant investigation. To explore this, we examined the effects of pilocarpine-induced seizures in transgenic mice where microglia/macrophages were conditionally ablated. We found that unilateral ablation of microglia from the dorsal hippocampus did not alter acute seizure sensitivity. However, when this procedure was coupled with lipopolysaccharide (LPS) <span class="hlt">preconditioning</span> (1 mg/kg given 24 h prior to acute seizure), we observed a significant pro-convulsant phenomenon. This effect was associated with lower metabolic activation in the ipsilateral hippocampus during acute seizures, and could be attributed to activity in the mossy fiber pathway. These findings reveal that <span class="hlt">preconditioning</span> with LPS 24 h prior to seizure induction may have a protective effect which is abolished by unilateral hippocampal microglia/macrophage ablation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5458149','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5458149"><span id="translatedtitle"><span class="hlt">Preconditioning</span> technique for indefinite systems resulting from mixed approximations of elliptic problems</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bramble, J.H.; Pasciak, J.E.</p> <p>1988-01-01</p> <p>This paper provides a <span class="hlt">preconditioned</span> iterative technique for the solution of saddle point problems. These problems typically arise in the numerical approximation of partial differential equations by Lagrange multiplier techniques and/or mixed methods. The saddle point problem is reformulated as a symmetric positive definite system, which is then solved by conjugate gradient iteration. Applications to the equations of elasticity and Stokes are discussed and the results of numerical experiments are given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4532962','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4532962"><span id="translatedtitle">Effects of Remifentanil <span class="hlt">Preconditioning</span> on Osteoblasts under Hypoxia-Reoxygenation Condition</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Baik, Seung-Wan; Park, Bong-Soo; Kim, Yong-Ho; Kim, Yong-Deok; Kim, Cheul-Hong; Yoon, Ji-Young; Yoon, Ji-Uk</p> <p>2015-01-01</p> <p>Background: Ischemia-reperfusion of bone occurs in a variety of clinical conditions, such as orthopedic arthroplasty, plastic gnathoplasty, spinal surgery, and amputation. Usually, cellular models of hypoxia-reoxygenation reflect in vivo models of ischemia-reperfusion. With respect to hypoxia-reoxygenation conditions, the effects of remifentanil on osteogenesis have received little attention. Therefore, we investigated the effects of remifentanil on the proliferation and differentiation of osteoblasts during hypoxic-reoxygenation. Methods: After remifentanil (0.1, 1 ng/mL) <span class="hlt">preconditioning</span> for 2 hours, human osteoblasts were cultured under 1% oxygen tension for 24 hours. Thereafter, the cells were reoxygenated for 12 hours at 37 °C. The naloxone groups were treated with naloxone for 30 minutes before remifentanil treatment. We measured cell viability via MTT assay. Osteoblast maturation was determined by assay of bone nodular mineralization. Quantitative PCR and western blot methods were used to determine BMP-2, osteocalcin, Akt, type I collagen, osterix, TGF-?1, HIF-1?, and RUNX2 expression levels. Results: Osteoblast viability and bone nodular mineralization by osteoblasts is recovered by remifentanil <span class="hlt">preconditioning</span> from hypoxia-reoxygenation insult. During hypoxic-reoxygenation condition, remifentanil <span class="hlt">preconditioning</span> induced the expression of BMP-2, osteocalcin, Akt, type I collagen, osterix, TGF-?1, HIF-1?, and RUNX2 in osteoblasts. Conclusions: Under hypoxia-reoxygenation conditions, remifentanil <span class="hlt">preconditioning</span> enhanced the cell viability and maturation of osteoblasts, and stimulated the expression of proteins associated with osteoblast proliferation and differentiation of the osteoblast. Our results suggest that remifentanil may help in the treatment of bone stress injuries. PMID:26283875</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25982835','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25982835"><span id="translatedtitle">Reactive astrocytes and therapeutic potential in focal <span class="hlt">ischemic</span> stroke.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Choudhury, Gourav Roy; Ding, Shinghua</p> <p>2016-01-01</p> <p>Astrocytes are specialized and the most abundant cell type in the central nervous system (CNS). They play important roles in the physiology of the brain. Astrocytes are also critically involved in many CNS disorders including focal <span class="hlt">ischemic</span> stroke, the leading cause of brain injury and death in patients. One of the prominent pathological features of a focal <span class="hlt">ischemic</span> stroke is reactive astrogliosis and glial scar formation. Reactive astrogliosis is accompanied with changes in morphology, proliferation, and gene expression in the reactive astrocytes. This study provides an overview of the most recent advances in astrocytic Ca(2+) signaling, spatial, and temporal dynamics of the morphology and proliferation of reactive astrocytes as well as signaling pathways involved in the reactive astrogliosis after <span class="hlt">ischemic</span> stroke based on results from experimental studies performed in various animal models. This review also discusses the therapeutic potential of reactive astrocytes in focal <span class="hlt">ischemic</span> stroke. As reactive astrocytes exhibit high plasticity, we suggest that modulation of local reactive astrocytes is a promising strategy for cell-based stroke therapy. PMID:25982835</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Myocardial+AND+infarction&pg=4&id=ED251707','ERIC'); return false;" href="http://eric.ed.gov/?q=Myocardial+AND+infarction&pg=4&id=ED251707"><span id="translatedtitle">Medications Used in the Treatment of <span class="hlt">Ischemic</span> Heart Disease.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Plummer, Nancy; Michael, Nancy, Ed.</p> <p></p> <p>This module on medications used in the treatment of <span class="hlt">ischemic</span> heart disease is intended for use in inservice or continuing education programs for persons who administer medications in long-term care facilities. Instructor information, including teaching suggestions, and a listing of recommended audiovisual materials and their sources appear first.…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/197837','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/197837"><span id="translatedtitle"><span class="hlt">Preconditioned</span> gradient methods for sparse linear systems for very `large structural` problems</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Abu-Shumays, I.K.; Hutula, D.N.; Haan, J.J.; Myers, G.T.</p> <p>1995-12-01</p> <p>This paper deals with background and practical experience with <span class="hlt">preconditioned</span> gradient methods for sparse linear systems for `very large` structural problems. The conjugate gradient method with diagonal <span class="hlt">preconditioning</span> (CG/D) is demonstrated to substantially increase the size of structural problems that can be analyzed, significantly reduce computer storage requirements, and cut computing cost; thus allowing for much more detailed modeling and increased engineering efficiency. For one case for a structural system with 396,087 unknowns, the conjugate gradient method with diagonal <span class="hlt">preconditioning</span> is demonstrated to be a factor of sixty faster than the direct method. For certain problems, however, the number of iterations required by the CG/D method is excessive and improved methods are needed. A stand-alone iterative solver research computer program was developed to evaluate the merits of various matrix preconditioners. A matrix preconditoner based on a shifted incomplete Cholesky factorization algorithm was demonstrated to be superior to other choices. The stand-alone program incorporates an effective data management strategy which utilizes disk and solid state auxiliary computer storage devices to make it possible to efficiently solve excessively large structural problems on state-of-the-art vector and parallel computers. The background of gradient methods, algorithms for their implementation, and practical experience in their applications to structural problems are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4612942','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4612942"><span id="translatedtitle">The protective effect of intraperitoneal medical ozone <span class="hlt">preconditioning</span> and treatment on hepatotoxicity induced by methotrexate</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Aslaner, Arif; Çak?r, Tu?rul; Çelik, Betül; Do?an, U?ur; Akyüz, Cebrail; Ba?türk, Ahmet; Polat, Cemal; Gündüz, Umut; Mayir, Burhan; ?ehirli, Ahmet Özer</p> <p>2015-01-01</p> <p>The aim of this study is to determine the effects of medical ozone <span class="hlt">preconditioning</span> and treatment on the methotrexate acute induced hepatotoxicity in rats that has not reports elsewhere. Eighteen rats were randomly assigned into three equal groups; control, Mtx and Mtx with ozone. Hepatotoxicity was performed with a single dose of 20 mg/kg Mtx to group 2 and group 3 at the fifteenth day. The medical ozone <span class="hlt">preconditioning</span> was administered intraperitonealy in group 3 for fifteen days and more five days after inducing Mtx. The other rats of the group 1 and 2 received saline injection. At the twentyfirst day the blood and the liver tissue samples were obtained to measure the levels of liver enzymes ALT and AST, proinflamatory cytokines TNF-?, IL-1?, malondialdehyde, glutathione and myeloperoxidase. And the histolopatological examination was evaluated for injury score. In our study Mtx administration caused a significant increase on the liver enzymes ALT and AST, the tissue MDA and MPO activity and significant decrease in the tissue GSH. Moreover the both pro-inflammatory cytokines were significantly increased in the Mtx group. Medical ozone <span class="hlt">preconditioning</span> and treatment reversed all these biochemical parameters and histopathological changes of the hepatotoxicity induced by Mtx. We conclude that medical ozone ameliorates Mtx induced hepatotoxicity in rats. PMID:26550257</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25419789','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25419789"><span id="translatedtitle">Voluntary Exercise <span class="hlt">Preconditioning</span> Activates Multiple Antiapoptotic Mechanisms and Improves Neurological Recovery after Experimental Traumatic Brain Injury.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhao, Zaorui; Sabirzhanov, Boris; Wu, Junfang; Faden, Alan I; Stoica, Bogdan A</p> <p>2015-09-01</p> <p>Physical activity can attenuate neuronal loss, reduce neuroinflammation, and facilitate recovery after brain injury. However, little is known about the mechanisms of exercise-induced neuroprotection after traumatic brain injury (TBI) or its modulation of post-traumatic neuronal cell death. Voluntary exercise, using a running wheel, was conducted for 4 weeks immediately preceding (<span class="hlt">preconditioning</span>) moderate-level controlled cortical impact (CCI), a well-established experimental TBI model in mice. Compared to nonexercised controls, exercise <span class="hlt">preconditioning</span> (pre-exercise) improved recovery of sensorimotor performance in the beam walk task, as well as cognitive/affective functions in the Morris water maze, novel object recognition, and tail-suspension tests. Further, pre-exercise reduced lesion size, attenuated neuronal loss in the hippocampus, cortex, and thalamus, and decreased microglial activation in the cortex. In addition, exercise <span class="hlt">preconditioning</span> activated the brain-derived neurotrophic factor pathway before trauma and amplified the injury-dependent increase in heat shock protein 70 expression, thus attenuating key apoptotic pathways. The latter include reduction in CCI-induced up-regulation of proapoptotic B-cell lymphoma 2 (Bcl-2)-homology 3-only Bcl-2 family molecules (Bid, Puma), decreased mitochondria permeabilization with attenuated release of cytochrome c and apoptosis-inducing factor (AIF), reduced AIF translocation to the nucleus, and attenuated caspase activation. Given these neuroprotective actions, voluntary physical exercise may serve to limit the consequences of TBI. PMID:25419789</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SPIE.9067E..1ZY','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SPIE.9067E..1ZY"><span id="translatedtitle">Completeness set proof of <span class="hlt">precondition</span> and post-condition types of activity in any EPM</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yu, Qian; Li, Tong; Liu, JinZhuo; Zhang, Xuan; Yu, Yong</p> <p>2013-12-01</p> <p>Software evolution process model (EPM) is created in terms of a formal evolution process meta-model (EPMM) and semi-formal approach to modeling based on EPMM [1]. In order to better manage and control the software evolution process and make the best of existing software technology, the method to transform any EPM to its execution model based logic programming has been proposed. Completeness of conversion depends on completeness of the rules, that is, all the expressions of the original model are found the correspondence in the target model. Since transformation rules are proposed based on <span class="hlt">precondition</span> or post-condition types of activities in anyone EPM, this need to prove that activity type set in anyone EPM is completeness set. To this end, the <span class="hlt">precondition</span> and post-condition of activities in EPM are classified based on analyzing all expressions in EPMs and the semantics of the activity execution. Type completeness set of activity's <span class="hlt">precondition</span> and its post-condition is presented. Lastly we prove that the activity type set in anyone EPM is completeness set by mathematical induction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4267453','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4267453"><span id="translatedtitle"><span class="hlt">Pre-Conditioning</span> with Low-Level Laser (Light) Therapy: Light Before the Storm</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Agrawal, Tanupriya; Gupta, Gaurav K.; Rai, Vikrant; Carroll, James D.; Hamblin, Michael R.</p> <p>2014-01-01</p> <p><span class="hlt">Pre-conditioning</span> by ischemia, hyperthermia, hypothermia, hyperbaric oxygen (and numerous other modalities) is a rapidly growing area of investigation that is used in pathological conditions where tissue damage may be expected. The damage caused by surgery, heart attack, or stroke can be mitigated by pre-treating the local or distant tissue with low levels of a stress-inducing stimulus, that can induce a protective response against subsequent major damage. Low-level laser (light) therapy (LLLT) has been used for nearly 50 years to enhance tissue healing and to relieve pain, inflammation and swelling. The photons are absorbed in cytochrome(c) oxidase (unit four in the mitochondrial respiratory chain), and this enzyme activation increases electron transport, respiration, oxygen consumption and ATP production. A complex signaling cascade is initiated leading to activation of transcription factors and up- and down-regulation of numerous genes. Recently it has become apparent that LLLT can also be effective if delivered to normal cells or tissue before the actual insult or trauma, in a <span class="hlt">pre-conditioning</span> mode. Muscles are protected, nerves feel less pain, and LLLT can protect against a subsequent heart attack. These examples point the way to wider use of LLLT as a <span class="hlt">pre-conditioning</span> modality to prevent pain and increase healing after surgical/medical procedures and possibly to increase athletic performance. PMID:25552961</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19950020275','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19950020275"><span id="translatedtitle">A decentralized software bus based on <span class="hlt">IP</span> multicas ting</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Callahan, John R.; Montgomery, Todd</p> <p>1995-01-01</p> <p>We describe decentralized reconfigurable implementation of a conference management system based on the low-level Internet Protocol (<span class="hlt">IP</span>) multicasting protocol. <span class="hlt">IP</span> multicasting allows low-cost, world-wide, two-way transmission of data between large numbers of conferencing participants through the Multicasting Backbone (MBone). Each conference is structured as a software bus -- a messaging system that provides a run-time interconnection model that acts as a separate agent (i.e., the bus) for routing, queuing, and delivering messages between distributed programs. Unlike the client-server interconnection model, the software bus model provides a level of indirection that enhances the flexibility and reconfigurability of a distributed system. Current software bus implementations like POLYLITH, however, rely on a centralized bus process and point-to-point protocols (i.e., TCP/<span class="hlt">IP</span>) to route, queue, and deliver messages. We implement a software bus called the MULTIBUS that relies on a separate process only for routing and uses a reliable <span class="hlt">IP</span> multicasting protocol for delivery of messages. The use of multicasting means that interconnections are independent of <span class="hlt">IP</span> machine addresses. This approach allows reconfiguration of bus participants during system execution without notifying other participants of new <span class="hlt">IP</span> addresses. The use of <span class="hlt">IP</span> multicasting also permits an economy of scale in the number of participants. We describe the MULITIBUS protocol elements and show how our implementation performs better than centralized bus implementations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006SPIE.6357E..3RZ','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006SPIE.6357E..3RZ"><span id="translatedtitle">Method of video capture port design for <span class="hlt">IP</span> camera</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Li; Ruan, Shuangchen; Zhang, Min; Liu, Chengxiang</p> <p>2006-11-01</p> <p>The <span class="hlt">IP</span> surveillance market is growing significantly and is receiving global attention now. <span class="hlt">IP</span> camera is the heart of this new surveillance system. As the key component of <span class="hlt">IP</span> camera, video capture port contributes greatly to camera's cost. CCD image sensors are employed in most <span class="hlt">IP</span> camera for its excellent performance and maturity in the market. In fact, new types of CMOS image sensors have become possible recent years due to CMOS technology improvements. This paper presents a design of an <span class="hlt">IP</span> camera's video capture port using CMOS image sensor based on embedded environment. Also contained is a brief introduction to the hardware design including the interface and PCB layout. The paper also provides information on setup of important registers, functions usage and debug tips. The design was tested on an <span class="hlt">IP</span> camera which has been on market for three years. The results show that using CMOS image sensor can achieve good image and save cost. Therefore, it is well suited for the surveillance field where image resolution is not the focus. The method can easily be extended to any other <span class="hlt">IP</span> camera design with little change both in hardware and software.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ASPC..495..111M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ASPC..495..111M"><span id="translatedtitle">Reviewing Ch<span class="hlt">IPS</span>, The Chandra Imaging and Plotting System</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miller, J.; Burke, D. J.; Evans, I. N.; Evans, J. D.; McLaughlin, W.</p> <p>2015-09-01</p> <p>The Chandra Imaging and Plotting System (Ch<span class="hlt">IPS</span>) is a 2D plotting system designed to allow users to easily create, manipulate, and produce publication quality visualizations. Ch<span class="hlt">IPS</span> has a simple but very powerful interactive interface that allows users to dynamically modify the contents and layout of their plots quickly and efficiently, with the results of any changes being immediately visible. Ch<span class="hlt">IPS</span> allows users to construct their plots fully interactively, and then save the final plot commands as a Python script. This bypasses the need to iteratively edit and rerun the script when developing the plot. Features such as undo and redo commands allow users to easily step backwards and forwards through previous commands, while the ability so save Ch<span class="hlt">IPS</span> sessions in a platform-independent state file allows the session to be restored at any time, even on another machine. Because Ch<span class="hlt">IPS</span> offers a Python interface, users can analyze their data using the broad array of modules offered in Python, and visualize the information in Ch<span class="hlt">IPS</span> at the same time. In this paper we explore the design decisions behind the development of Ch<span class="hlt">IPS</span> and some of the lessons learned along the way.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25249628','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25249628"><span id="translatedtitle">MACE: model based analysis of Ch<span class="hlt">IP</span>-exo.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Liguo; Chen, Junsheng; Wang, Chen; Uusküla-Reimand, Liis; Chen, Kaifu; Medina-Rivera, Alejandra; Young, Edwin J; Zimmermann, Michael T; Yan, Huihuang; Sun, Zhifu; Zhang, Yuji; Wu, Stephen T; Huang, Haojie; Wilson, Michael D; Kocher, Jean-Pierre A; Li, Wei</p> <p>2014-11-10</p> <p>Understanding the role of a given transcription factor (TF) in regulating gene expression requires precise mapping of its binding sites in the genome. Chromatin immunoprecipitation-exo, an emerging technique using ? exonuclease to digest TF unbound DNA after Ch<span class="hlt">IP</span>, is designed to reveal transcription factor binding site (TFBS) boundaries with near-single nucleotide resolution. Although Ch<span class="hlt">IP</span>-exo promises deeper insights into transcription regulation, no dedicated bioinformatics tool exists to leverage its advantages. Most Ch<span class="hlt">IP</span>-seq and Ch<span class="hlt">IP</span>-chip analytic methods are not tailored for Ch<span class="hlt">IP</span>-exo, and thus cannot take full advantage of high-resolution Ch<span class="hlt">IP</span>-exo data. Here we describe a novel analysis framework, termed MACE (model-based analysis of Ch<span class="hlt">IP</span>-exo) dedicated to Ch<span class="hlt">IP</span>-exo data analysis. The MACE workflow consists of four steps: (i) sequencing data normalization and bias correction; (ii) signal consolidation and noise reduction; (iii) single-nucleotide resolution border peak detection using the Chebyshev Inequality and (iv) border matching using the Gale-Shapley stable matching algorithm. When applied to published human CTCF, yeast Reb1 and our own mouse ONECUT1/HNF6 Ch<span class="hlt">IP</span>-exo data, MACE is able to define TFBSs with high sensitivity, specificity and spatial resolution, as evidenced by multiple criteria including motif enrichment, sequence conservation, direct sequence pileup, nucleosome positioning and open chromatin states. In addition, we show that the fundamental advance of MACE is the identification of two boundaries of a TFBS with high resolution, whereas other methods only report a single location of the same event. The two boundaries help elucidate the in vivo binding structure of a given TF, e.g. whether the TF may bind as dimers or in a complex with other co-factors. PMID:25249628</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4227761','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4227761"><span id="translatedtitle">MACE: model based analysis of Ch<span class="hlt">IP</span>-exo</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wang, Liguo; Chen, Junsheng; Wang, Chen; Uusküla-Reimand, Liis; Chen, Kaifu; Medina-Rivera, Alejandra; Young, Edwin J.; Zimmermann, Michael T.; Yan, Huihuang; Sun, Zhifu; Zhang, Yuji; Wu, Stephen T.; Huang, Haojie; Wilson, Michael D.; Kocher, Jean-Pierre A.; Li, Wei</p> <p>2014-01-01</p> <p>Understanding the role of a given transcription factor (TF) in regulating gene expression requires precise mapping of its binding sites in the genome. Chromatin immunoprecipitation-exo, an emerging technique using ? exonuclease to digest TF unbound DNA after Ch<span class="hlt">IP</span>, is designed to reveal transcription factor binding site (TFBS) boundaries with near-single nucleotide resolution. Although Ch<span class="hlt">IP</span>-exo promises deeper insights into transcription regulation, no dedicated bioinformatics tool exists to leverage its advantages. Most Ch<span class="hlt">IP</span>-seq and Ch<span class="hlt">IP</span>-chip analytic methods are not tailored for Ch<span class="hlt">IP</span>-exo, and thus cannot take full advantage of high-resolution Ch<span class="hlt">IP</span>-exo data. Here we describe a novel analysis framework, termed MACE (model-based analysis of Ch<span class="hlt">IP</span>-exo) dedicated to Ch<span class="hlt">IP</span>-exo data analysis. The MACE workflow consists of four steps: (i) sequencing data normalization and bias correction; (ii) signal consolidation and noise reduction; (iii) single-nucleotide resolution border peak detection using the Chebyshev Inequality and (iv) border matching using the Gale-Shapley stable matching algorithm. When applied to published human CTCF, yeast Reb1 and our own mouse ONECUT1/HNF6 Ch<span class="hlt">IP</span>-exo data, MACE is able to define TFBSs with high sensitivity, specificity and spatial resolution, as evidenced by multiple criteria including motif enrichment, sequence conservation, direct sequence pileup, nucleosome positioning and open chromatin states. In addition, we show that the fundamental advance of MACE is the identification of two boundaries of a TFBS with high resolution, whereas other methods only report a single location of the same event. The two boundaries help elucidate the in vivo binding structure of a given TF, e.g. whether the TF may bind as dimers or in a complex with other co-factors. PMID:25249628</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4635746','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4635746"><span id="translatedtitle"><span class="hlt">Ischemic</span> Stroke in Young Adults and Preexisting Psychiatric Disorders</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Chiu, Yu-Chuan; Bai, Ya-Mei; Su, Tung-Ping; Chen, Tzeng-Ji; Chen, Mu-Hong</p> <p>2015-01-01</p> <p>Abstract Previous studies showed that psychiatric disorders such as major depression, bipolar disorders, and alcohol misuse are associated with an increased risk of <span class="hlt">ischemic</span> stroke. However, the link between psychiatric disorders and stroke in the young population is rarely investigated. Using the Taiwan National Health Insurance Research Database, 2063 young adults aged between 18 and 45 years with <span class="hlt">ischemic</span> stroke and 8252 age- and sex-matched controls were enrolled in our study between 1998 and 2011. Participants who had preexisting psychiatric disorders were identified. After adjusting for preexisting physical disorders and demographic data, patients with <span class="hlt">ischemic</span> stroke had an increased risk of having preexisting psychiatric disorders, including bipolar disorder (odds ratio [OR]: 2.23, 95% confidence interval [CI]: 1.06?4.67), unipolar depression (OR: 2.15, 95% CI: 1.62?2.86), anxiety disorders (OR: 2.63, 95% CI: 1.87?3.69), and alcohol use disorders (OR: 2.86, 95% CI: 1.79?4.57). Young <span class="hlt">ischemic</span> stroke (age ?30 years) was related to the risk of preexisting unipolar depression (OR: 1.49, 95% CI: 1.05?2.11), anxiety disorders (OR: 1.99, 95% CI: 1.33?2.97), and alcohol use disorders (OR: 2.54, 95% CI: 1.55?4.14); very young stroke (age <30 years) was only associated with the risk of preexisting unipolar depression (OR: 4.15, 95% CI: 1.47?11.72). Patients who had experienced <span class="hlt">ischemic</span> stroke at age younger than 45 years had a higher risk of having pre-existing bipolar disorder, unipolar depression, anxiety disorders, and alcohol use disorders than those who did not after adjusting for demographic data and stroke-related medical comorbidities. PMID:26402806</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22054514','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22054514"><span id="translatedtitle">Increased Risk of <span class="hlt">Ischemic</span> Stroke in Young Nasopharyngeal Carcinoma Patients</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lee, Ching-Chih; Su, Yu-Chieh; Ho, Hsu-Chueh; Hung, Shih-Kai; Lee, Moon-Sing; Chiou, Wen-Yen; Chou, Pesus; Huang, Yung-Sung</p> <p>2011-12-01</p> <p>Purpose: Radiation/chemoradiotherapy-induced carotid stenosis and cerebrovascular events in patients with nasopharyngeal carcinoma (NPC) can cause severe disability and even death. This study aimed to estimate the risk of <span class="hlt">ischemic</span> stroke in this patient population over more than 10 years of follow-up. Methods and Materials: The study cohorts consisted of all patients hospitalized with a principal diagnosis of NPC (n = 1094), whereas patients hospitalized for an appendectomy during 1997 and 1998 (n = 4376) acted as the control group and surrogate for the general population. Cox proportional hazard model was performed as a means of comparing the stroke-free survival rate between the two cohorts after adjusting for possible confounding and risk factors. Results: Of the 292 patients with <span class="hlt">ischemic</span> strokes, 62 (5.7%) were from the NPC cohort and 230 (5.3%) were from the control group. NPC patients ages 35-54 had a 1.66 times (95% CI, 1.16-2.86; p = 0.009) higher risk of <span class="hlt">ischemic</span> stroke after adjusting for patient characteristics, comorbidities, geographic region, urbanization level of residence, and socioeconomic status. There was no statistical difference in <span class="hlt">ischemic</span> stroke risk between the NPC patients and appendectomy patients ages 55-64 years (hazard ratio = 0.87; 95% CI, 0.56-1.33; p = 0.524) after adjusting for other factors. Conclusions: Young NPC patients carry a higher risk for <span class="hlt">ischemic</span> stroke than the general population. Besides regular examinations of carotid duplex, different irradiation strategies or using new technique of radiotherapy, such as intensity modulated radiation therapy or volumetric modulated arc therapy, should be considered in young NPC patients.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20010047618','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20010047618"><span id="translatedtitle">Application of Mobile-<span class="hlt">ip</span> to Space and Aeronautical Networks</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Leung, Kent; Shell, Dan; Ivancic, William D.; Stewart, David H.; Bell, Terry L.; Kachmar, Brian A.</p> <p>2001-01-01</p> <p>The National Aeronautics and Space Administration (NASA) is interested in applying mobile Internet protocol (mobile-<span class="hlt">ip</span>) technologies to its space and aeronautics programs. In particular, mobile-<span class="hlt">ip</span> will play a major role in the Advanced Aeronautic Transportation Technology (AAT-F), the Weather Information Communication (WINCOMM), and the Small Aircraft Transportation System (SATS) aeronautics programs. This paper describes mobile-<span class="hlt">ip</span> and mobile routers--in particular, the features, capabilities, and initial performance of the mobile router are presented. The application of mobile-router technology to NASA's space and aeronautics programs is also discussed.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19840017012&hterms=first+mover&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dfirst%2Bmover','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19840017012&hterms=first+mover&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dfirst%2Bmover"><span id="translatedtitle">Actuator development for the Instrument Pointing System (<span class="hlt">IPS</span>)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Suttner, K.</p> <p>1984-01-01</p> <p>The mechanisms of the instrument pointing system (<span class="hlt">IPS</span>) are described. Particular emphasis is placed on the actuators which are necessary for operating the <span class="hlt">IPS</span>. The actuators are described as follows: (1) two linear actuators that clamp the gimbals down during ascent and descent; (2) two linear actuators that attach the payload to the <span class="hlt">IPS</span> during the mission, and release it into the payload clamps; (3) one rotational actuator that opens and closes the payload clamps; and (4) three identical drive units that represent the three orthogonal gimbal axes and are the prime movers for pointing. Design features, manufacturing problems, test performance, and results are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20040081293&hterms=find+ip&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dfind%2Bip','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20040081293&hterms=find+ip&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dfind%2Bip"><span id="translatedtitle">Handbook for Using <span class="hlt">IP</span> Protocols for Space Missions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hogie, Keith; Criscuolo, Ed; Parise, Ron</p> <p>2004-01-01</p> <p>This presentation will provide a summary of a handbook developed at GSFC last year that contains concepts and guidelines for using Internet protocols for space missions. It will include topics on: Lessons learned from current Space <span class="hlt">IP</span> mission. General architectural issues related to use of <span class="hlt">IP</span> in space. Operational scenarios for common space data transfer applications. Security issues. A general review of protocols applicable for use with <span class="hlt">IP</span> in space. The presentation will also pose questions on what sort of information would be useful in future versions of the document.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009IEITE..92.1232I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009IEITE..92.1232I"><span id="translatedtitle">Multi-Core/Multi-<span class="hlt">IP</span> Technology for Embedded Applications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Irie, Naohiko; Hattori, Toshihiro</p> <p></p> <p>SoC has driven the evolution of embedded systems or consumer electronics. Multi-core/multi-<span class="hlt">IP</span> is the key technology to integrate many functions on a SoC for future embedded applications. In this paper, the transition of SoC and its required functions for cellular phones as an example is described. And the state-of-the-art multi-core technology of homogeneous type and heterogeneous type are shown. When many cores and <span class="hlt">IPs</span> are integrated on a chip, collaboration between cores and <span class="hlt">IPs</span> becomes important to meet requirement. To realize it, “MPSoC Platform” concept and elementary technology for this platform is described.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/2054299','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/2054299"><span id="translatedtitle"><span class="hlt">I.P</span>. Pavlov as a youth.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Windholz, G</p> <p>1991-01-01</p> <p>Ivan P. Pavlov's youthful relations with parents and siblings, formal education, and social activities in Riazan' are described. The Pavlovs, a highly achievement-oriented family descending from a lowly serf, improved their social status by serving the Russian Orthodox Church. Pavlov, the son of a priest, studied in the 1860s at the Riazan' Ecclesiastic Seminary for priesthood. The turbulent 1860s' decade was a period of social and political reforms. Western ideas and science were introduced to Russia. The ambitious and idealistic <span class="hlt">I.P</span>. Pavlov was influenced by popular essays written by the journalist D.I. Pisarev, the works of the German physiologist J. Moleschott, the English writer G.H. Lewes, the German zoologist C. Vogt and the physiologist M.I. Sechenov. Losing his religious faith, Pavlov abandoned the traditional goal of becoming a priest, and, convinced that science was a road to truth and progress, left Riazan' to study natural science at the University of St. Petersburg. PMID:2054299</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2596672','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2596672"><span id="translatedtitle">An integrated system CisGenome for analyzing Ch<span class="hlt">IP</span>-chip and Ch<span class="hlt">IP</span>-seq data</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ji, Hongkai; Jiang, Hui; Ma, Wenxiu; Johnson, David S.; Myers, Richard M.; Wong, Wing H.</p> <p>2008-01-01</p> <p>CisGenome is a software system for analyzing genome-wide chromatin immunoprecipitation (Ch<span class="hlt">IP</span>) data. It is designed to meet all basic needs of Ch<span class="hlt">IP</span> data analyses, including visualization, data normalization, peak detection, false discovery rate (FDR) computation, gene-peak association, and sequence and motif analysis. In addition to implementing previously published Ch<span class="hlt">IP</span>-chip analysis methods, the software contains new statistical methods designed specifically for Ch<span class="hlt">IP</span>-seq data. CisGenome has a modular design so that it supports interactive analyses through a graphic user interface as well as customized batch-mode computation for advanced data mining. A built-in browser allows visualization of array images, signals, gene structure, conservation, and DNA sequence and motif information. We illustrate the use of these tools by a comparative analysis of Ch<span class="hlt">IP</span>-chip and Ch<span class="hlt">IP</span>-seq data for the transcription factor NRSF/REST, a study of Ch<span class="hlt">IP</span>-seq analysis without negative control sample, and an analysis of a novel motif in Nanog- and Sox2-binding regions. PMID:18978777</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4590236','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4590236"><span id="translatedtitle">Exercise <span class="hlt">preconditioning</span> exhibits neuroprotective effects on hippocampal CA1 neuronal damage after cerebral ischemia</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Shamsaei, Nabi; Khaksari, Mehdi; Erfani, Sohaila; Rajabi, Hamid; Aboutaleb, Nahid</p> <p>2015-01-01</p> <p>Recent evidence has suggested the neuroprotective effects of physical exercise on cerebral <span class="hlt">ischemic</span> injury. However, the role of physical exercise in cerebral ischemia-induced hippocampal damage remains controversial. The aim of the present study was to evaluate the effects of pre-ischemia treadmill training on hippocampal CA1 neuronal damage after cerebral ischemia. Male adult rats were randomly divided into control, ischemia and exercise + ischemia groups. In the exercise + ischemia group, rats were subjected to running on a treadmill in a designated time schedule (5 days per week for 4 weeks). Then rats underwent cerebral ischemia induction through occlusion of common carotids followed by reperfusion. At 4 days after cerebral ischemia, rat learning and memory abilities were evaluated using passive avoidance memory test and rat hippocampal neuronal damage was detected using Nissl and TUNEL staining. Pre-<span class="hlt">ischemic</span> exercise significantly reduced the number of TUNEL-positive cells and necrotic cell death in the hippocampal CA1 region as compared to the ischemia group. Moreover, pre-<span class="hlt">ischemic</span> exercise significantly prevented ischemia-induced memory dysfunction. Pre-<span class="hlt">ischemic</span> exercise mighct prevent memory deficits after cerebral ischemia through rescuing hippocampal CA1 neurons from ischemia-induced degeneration. PMID:26487851</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4599476','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4599476"><span id="translatedtitle">Long-Term Antiplatelet Mono- and Dual Therapies After <span class="hlt">Ischemic</span> Stroke or Transient <span class="hlt">Ischemic</span> Attack: Network Meta-Analysis</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Xie, Wuxiang; Zheng, Fanfan; Zhong, Baoliang; Song, Xiaoyu</p> <p>2015-01-01</p> <p>Background The latest guidelines do not make clear recommendations on the selection of antiplatelet therapies for long-term secondary prevention of stroke. We aimed to integrate the available evidence to create hierarchies of the comparative efficacy and safety of long-term antiplatelet therapies after <span class="hlt">ischemic</span> stroke or transient <span class="hlt">ischemic</span> attack. Methods and Results We performed a network meta-analysis of randomized controlled trials to compare 11 antiplatelet therapies in patients with <span class="hlt">ischemic</span> stroke or transient <span class="hlt">ischemic</span> attack. In December 2014, we searched Medline, Embase, and the Cochrane Library database for trials. The search identified 24 randomized controlled trials including a total of 85 667 patients with antiplatelet treatments for at least 1 year. Cilostazol significantly reduced stroke recurrence in comparison with aspirin (odds ratio 0.66, 95% credible interval 0.44 to 0.92) and dipyridamole (odds ratio 0.57, 95% credible interval 0.34 to 0.95), respectively. Cilostazol also significantly reduced intracranial hemorrhage compared with aspirin, clopidogrel, terutroban, ticlopidine, aspirin plus clopidogrel, and aspirin plus dipyridamole. Aspirin plus clopidogrel could not significantly reduce stroke recurrence compared with monotherapies but caused significantly more major bleeding than all monotherapies except terutroban. The pooled estimates did not change materially in the sensitivity analyses of the primary efficacy outcome. Conclusions Long-term monotherapy was a better choice than long-term dual therapy, and cilostazol had the best risk–benefit profile for long-term secondary prevention after stroke or transient <span class="hlt">ischemic</span> attack. More randomized controlled trials in non–East Asian patients are needed to determine whether long-term use of cilostazol is the best option for the prevention of recurrent stroke. PMID:26304937</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://oaktrust.library.tamu.edu//handle/1969.1/5741','EPRINT'); return false;" href="http://oaktrust.library.tamu.edu//handle/1969.1/5741"><span id="translatedtitle">Rate-adaptive H.264 for TCP/<span class="hlt">IP</span> networks </span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Kota, Praveen</p> <p>2007-09-17</p> <p>While there has always been a tremendous demand for streaming video over TCP/<span class="hlt">IP</span> networks, the nature of the application still presents some challenging issues. These applications that transmit multimedia data over best-effort networks like...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://oaktrust.library.tamu.edu//handle/1969.1/ETD-TAMU-1998-THESIS-M64','EPRINT'); return false;" href="http://oaktrust.library.tamu.edu//handle/1969.1/ETD-TAMU-1998-THESIS-M64"><span id="translatedtitle">Performance comparison of native ATM vs <span class="hlt">IP</span> over ATM </span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Mohammed, Shajiuddin Asif</p> <p>1998-01-01</p> <p>engineers through its high bandwidth and multi traffic support. The robustness of the Internet Protocol (115 contributed to massive increase in Internet hosts globally. <span class="hlt">IP</span> is a connectionless protocol as opposed to ATM, ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ensc.sfu.ca/fas-info/ensc/people/faculty/ljilja/cnl/presentations/modupe/TMP_Lisbon/TMP_lisbon.pdf','EPRINT'); return false;" href="http://www.ensc.sfu.ca/fas-info/ensc/people/faculty/ljilja/cnl/presentations/modupe/TMP_Lisbon/TMP_lisbon.pdf"><span id="translatedtitle">Improving TCP performance in mobile satellite <span class="hlt">IP</span> communications</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Trajkovic, Ljiljana</p> <p></p> <p>: random BER is negligible The Internet: has witnessed tremendous growth in wireless <span class="hlt">IP</span> communications HTTP concerns: unlicensed operators/users interfere with existing systems hack into existing systems license</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70021135','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70021135"><span id="translatedtitle">Photometric studies of ? Scuti stars. I. <span class="hlt">IP</span> Virginis</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Joner, Michael D.; Hintz, Eric G.; Collier, Matthew W.</p> <p>1998-01-01</p> <p>We report 15 new times of maximum light for the ? Scuti star <span class="hlt">IP</span> Virginis (formerly known as SA 106?1024). An analysis of all times of maximum light indicates that <span class="hlt">IP</span> Vir has been decreasing in period at a constant rate of ? days day?1. Evidence is also presented that <span class="hlt">IP</span> Vir is a double?mode variable with a period ratio of . This period ratio predicts a [Fe/H] value of ?0.3. From photometric (uvby?) observations, we find a foreground reddening of .008 mag and a metallicity of [Fe/H] = +0.05. It is shown that [Fe/H] = ?0.3 is most likely the correct value. Intrinsic ? and c1?values, plotted in a model atmosphere grid, indicate a mean effective temperature, K, and a mean surface gravity, . All of these physical parameters support Landolt's initial conclusion that <span class="hlt">IP</span> Vir is an ordinary ? Sct star.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010IEITC..93.2188Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010IEITC..93.2188Y"><span id="translatedtitle">Identifying <span class="hlt">IP</span> Blocks with Spamming Bots by Spatial Distribution</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yun, Sangki; Kim, Byungseung; Bahk, Saewoong; Kim, Hyogon</p> <p></p> <p>In this letter, we develop a behavioral metric with which spamming botnets can be quickly identified with respect to their residing <span class="hlt">IP</span> blocks. Our method aims at line-speed operation without deep inspection, so only TCP/<span class="hlt">IP</span> header fields of the passing packets are examined. However, the proposed metric yields a high-quality receiver operating characteristics (ROC), with high detection rates and low false positive rates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24483317','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24483317"><span id="translatedtitle">[<span class="hlt">IPS</span> an ethical paradigm for biomedical research].</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gámez Escalona, José Antonio</p> <p>2013-01-01</p> <p>One of the greatest advances in molecular and cell biology was the discovery of the Induced Pluripotent Stem cells (<span class="hlt">iPS</span>) in mice, by Shinya Yamanka and his team in 2006. The possibility that these cells can be generated also in humans opens up unexpected ways of development for biomedicine. Its main contribution is the creation of a strong protocol that takes into account three major advances in biology such as; nuclear transfer techniques, the discovery of transcription factors associated with pluripotency and the isolation of mouse embryonic stem cells. A protocol that can be easily replicated in other laboratories to have the oportunity to design tests that allow modeling of many incurable diseases, drug testing for human cells or explore the possibilities of autologous transplants of tissues or organs. Yamanaka ethical motivation to find an alternative to embryonic stem cells (ES) and prevent the destruction of embryos produced by In Vitro Fertilization techniques (IVF), has proved to be a research model, in which the intuition of the ethical principles and its application in advanced biotechnology projects, has meant the opening of a whole new way of understanding the biology of embryonic development. It is clear that development, biologically understood (puede ser también ?treated?; tratado), is not a one-way street. The possibilities to deepen into the foundations of molecular biology and genetics, along with the expectations of its clinical applications have earned Yamanka the Nobel Prize in Medicine 2012, along with another great scholar Sir John Gurdon, discoverer of nuclear transfer techniques. PMID:24483317</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999SPIE.3528..393S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999SPIE.3528..393S"><span id="translatedtitle"><span class="hlt">IP</span> voice over ATM satellite: experimental results over satellite channels</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Saraf, Koroush A.; Butts, Norman P.</p> <p>1999-01-01</p> <p><span class="hlt">IP</span> telephony, a new technology to provide voice communication over traditional data networks, has the potential to revolutionize telephone communication within the modern enterprise. This innovation uses packetization techniques to carry voice conversations over <span class="hlt">IP</span> networks. This packet switched technology promises new integrated services, and lower cost long-distance communication compared to traditional circuit switched telephone networks. Future satellites will need to carry <span class="hlt">IP</span> traffic efficiently in order to stay competitive in servicing the global data- networking and global telephony infrastructure. However, the effects of Voice over <span class="hlt">IP</span> over switched satellite channels have not been investigated in detail. To fully understand the effects of satellite channels on Voice over <span class="hlt">IP</span> quality; several experiments were conducted at Lockheed Martin Telecommunications' Satellite Integration Lab. The result of those experiments along with suggested improvements for voice communication over satellite are presented in this document. First, a detailed introduction of <span class="hlt">IP</span> telephony as a suitable technology for voice communication over future satellites is presented. This is followed by procedures for the experiments, along with results and strategies. In conclusion we hope that these capability demonstrations will alleviate any uncertainty regarding the applicability of this technology to satellite networks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://dspace.mit.edu/handle/1721.1/59018','EPRINT'); return false;" href="http://dspace.mit.edu/handle/1721.1/59018"><span id="translatedtitle">Analysis of the mouse embryonic stem cell regulatory networks obtained by Ch<span class="hlt">IP</span>-chip and Ch<span class="hlt">IP</span>-PET</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Mathur, Divya</p> <p></p> <p>Background: Genome-wide approaches have begun to reveal the transcriptional networks responsible for pluripotency in embryonic stem (ES) cells. Chromatin Immunoprecipitation (Ch<span class="hlt">IP</span>) followed either by hybridization to a ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://nms.lcs.mit.edu/~mythili/research/imc05.ps','EPRINT'); return false;" href="http://nms.lcs.mit.edu/~mythili/research/imc05.ps"><span id="translatedtitle">Geographic Locality of <span class="hlt">IP</span> Prefixes Michael J. Freedman Mythili Vutukuru, Nick Feamster, Hari Balakrishnan</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p></p> <p></p> <p>and their implications on Internet routing. We find that (1) <span class="hlt">IP</span> prefixes may be too coarse­ grained for expressing of understanding the geographic prop­ erties of <span class="hlt">IP</span> prefixes, this paper makes three findings. First, an <span class="hlt">IP</span> prefix that as­ sume that hosts within an <span class="hlt">IP</span> prefix are topologically close. As expected, we find that ``shorter</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://nms.lcs.mit.edu/~mythili/research/imc05.pdf','EPRINT'); return false;" href="http://nms.lcs.mit.edu/~mythili/research/imc05.pdf"><span id="translatedtitle">Geographic Locality of <span class="hlt">IP</span> Prefixes Michael J. Freedman Mythili Vutukuru, Nick Feamster, Hari Balakrishnan</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p></p> <p></p> <p>and their implications on Internet routing. We find that (1) <span class="hlt">IP</span> prefixes may be too coarse- grained for expressing of understanding the geographic prop- erties of <span class="hlt">IP</span> prefixes, this paper makes three findings. First, an <span class="hlt">IP</span> prefix that as- sume that hosts within an <span class="hlt">IP</span> prefix are topologically close. As expected, we find that "shorter</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www-ee.eng.hawaii.edu/~sasaki/Papers/allerton02-sasakib.PDF','EPRINT'); return false;" href="http://www-ee.eng.hawaii.edu/~sasaki/Papers/allerton02-sasakib.PDF"><span id="translatedtitle">Survivable <span class="hlt">IP</span> Over WDM: An Efficient Mathematical Programming Problem Formulation1</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Sasaki, Galen H.</p> <p></p> <p>problem [2]. Given an <span class="hlt">IP</span> network topology, find routes for the corresponding lightpaths so that the IPSurvivable <span class="hlt">IP</span> Over WDM: An Efficient Mathematical Programming Problem Formulation1 1 To appear of laying out a survivable <span class="hlt">IP</span> network over a WDM network is considered. The links of the <span class="hlt">IP</span> network</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://halcyon.usc.edu/~pk/prasannawebsite/papers/2013/RangeTree_HPSR2013.pdf','EPRINT'); return false;" href="http://halcyon.usc.edu/~pk/prasannawebsite/papers/2013/RangeTree_HPSR2013.pdf"><span id="translatedtitle">Architecture and Performance Models for Scalable <span class="hlt">IP</span> Lookup Engines on FPGA*</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Hwang, Kai</p> <p></p> <p>Architecture and Performance Models for Scalable <span class="hlt">IP</span> Lookup Engines on FPGA* Yi-Hua E. Yang Xilinx on FPGA. A general BRTree-based <span class="hlt">IP</span> lookup solution features one or more linear pipelines with a large distribution. Index Terms--IPv4, IPv6, <span class="hlt">IP</span> lookup, FPGA I. INTRODUCTION Designing a scalable <span class="hlt">IP</span> lookup engine</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ru6.cti.gr/ru6-old/publications/6385853.pdf','EPRINT'); return false;" href="http://ru6.cti.gr/ru6-old/publications/6385853.pdf"><span id="translatedtitle">A Managed Bandwidth Service for <span class="hlt">IP</span> Networks C. Bouras C. Chantzi V. Kapoulas A. Sevasti</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p></p> <p></p> <p>of ATM switches at the core of service provider networks. Some of the largest <span class="hlt">IP</span> networks are based removed from the core of most <span class="hlt">IP</span> networks and replaced with core <span class="hlt">IP</span> routers. The reason is speedA Managed Bandwidth Service for <span class="hlt">IP</span> Networks C. Bouras C. Chantzi V. Kapoulas A. 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