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Sample records for partial ischemia model

  1. Chick embryo partial ischemia model: a new approach to study ischemia ex vivo.

    Directory of Open Access Journals (Sweden)

    Syamantak Majumder

    Full Text Available BACKGROUND: Ischemia is a pathophysiological condition due to blockade in blood supply to a specific tissue thus damaging the physiological activity of the tissue. Different in vivo models are presently available to study ischemia in heart and other tissues. However, no ex vivo ischemia model has been available to date for routine ischemia research and for faster screening of anti-ischemia drugs. In the present study, we took the opportunity to develop an ex vivo model of partial ischemia using the vascular bed of 4(th day incubated chick embryo. METHODOLOGY/PRINCIPAL FINDINGS: Ischemia was created in chick embryo by ligating the right vitelline artery using sterile surgical suture. Hypoxia inducible factor- 1 alpha (HIF-1alpha, creatine phospho kinase-MB and reactive oxygen species in animal tissues and cells were measured to confirm ischemia in chick embryo. Additionally, ranolazine, N-acetyl cysteine and trimetazidine were administered as an anti-ischemic drug to validate the present model. Results from the present study depicted that blocking blood flow elevates HIF-1alpha, lipid peroxidation, peroxynitrite level in ischemic vessels while ranolazine administration partially attenuates ischemia driven HIF-1alpha expression. Endothelial cell incubated on ischemic blood vessels elucidated a higher level of HIF-1alpha expression with time while ranolazine treatment reduced HIF-1alpha in ischemic cells. Incubation of caprine heart strip on chick embryo ischemia model depicted an elevated creatine phospho kinase-MB activity under ischemic condition while histology of the treated heart sections evoked edema and disruption of myofibril structures. CONCLUSIONS/SIGNIFICANCE: The present study concluded that chick embryo partial ischemia model can be used as a novel ex vivo model of ischemia. Therefore, the present model can be used parallel with the known in vivo ischemia models in understanding the mechanistic insight of ischemia development and in

  2. Comparison of partial and complete arterial occlusion models for studying intestinal ischemia

    International Nuclear Information System (INIS)

    Parks, D.A.; Grogaard, B.; Granger, D.N.

    1982-01-01

    Mucosal albumin clearance was measured in jejunal segments of dogs under control conditions and following complete or partial arterial occlusion of varying durations (1, 2, 3, or 4 hours). The rate of albumin clearance was estimated from the luminal perfusion rate and the activity of protein bound 125 I in the perfusate and plasma. Partial and total arterial occlusions of 60 minutes to 4 hours' duration produced significant increases in mucosal albumin clearance. The magnitude of the rise in albumin clearance was directly related to the duration of ischemia in both total and partial arterial occlusion models. However, the magnitude of the increase in albumin clearance was significantly greater with total arterial occlusion for any given duration of ischemia. The albumin clearance results obtained in the present study compare favorably with previously reported morphologic changes in the intestinal mucosa produced by both total and partial occlusion of the superior mesenteric artery. The agreement between morphologic and physiologic measurements indicates that mucosal albumin clearance may be a useful tool for studying the pathophysiology of intestinal ischemia

  3. Zero ischemia laparoscopic partial thulium laser nephrectomy.

    LENUS (Irish Health Repository)

    Thomas, Arun Z

    2013-11-01

    Laser technology presents a promising alternative to achieve tumor excision and renal hemostasis with or without hilar occlusion, yet its use in partial nephrectomy has not been significantly evaluated. We prospectively evaluated the thulium:yttrium-aluminum-garnet laser in laparoscopic partial nephrectomy (LPN) in our institution over a 1-year period.

  4. Animal models of cerebral ischemia

    Science.gov (United States)

    Khodanovich, M. Yu.; Kisel, A. A.

    2015-11-01

    Cerebral ischemia remains one of the most frequent causes of death and disability worldwide. Animal models are necessary to understand complex molecular mechanisms of brain damage as well as for the development of new therapies for stroke. This review considers a certain range of animal models of cerebral ischemia, including several types of focal and global ischemia. Since animal models vary in specificity for the human disease which they reproduce, the complexity of surgery, infarct size, reliability of reproduction for statistical analysis, and adequate models need to be chosen according to the aim of a study. The reproduction of a particular animal model needs to be evaluated using appropriate tools, including the behavioral assessment of injury and non-invasive and post-mortem control of brain damage. These problems also have been summarized in the review.

  5. Pathophysiological appraisal of a rat model of total hepatic ischemia with an extracorporeal portosystemic shunt.

    Science.gov (United States)

    Suzuki, S; Nakamura, S; Sakaguchi, T; Mitsuoka, H; Tsuchiya, Y; Kojima, Y; Konno, H; Baba, S

    1998-11-01

    Animal models of total hepatic ischemia (THI) and reperfusion injury are restricted by concomitant splanchnic congestion. This study was performed to determine the requirement suitable for an extracorporeal portosystemic shunt (PSS) to maintain the intestinal integrity in a rat model of THI. Using a polyethylene tube (0.86 or 1 mm i.d.), PSS was placed between the mesenteric and jugular veins. Comparison was done between THI models with or without PSS and a partial ischemia model with hepatectomy of the nonischemic lobes. Well-tolerated hepatic ischemic period, portal pressure after 10 min of hepatic ischemia, portal endotoxin levels at 1 h after reperfusion, histological features of the small bowel just before reperfusion, and local jejunal and ileal blood hemoglobin oxygen saturation index (ISO2) were compared among the models. Animals without PSS poorly tolerated 30 min of THI. Animals receiving THI with PSS or partial hepatic ischemia tolerated a longer ischemic period (60 min) with a significantly higher small bowel ISO2, lower portal pressure and endotoxin levels (P tube as well as partial hepatic ischemia were significantly lower than those after THI with PSS using a 0.86-mm i.d. tube. THI with PSS using a 1-mm i.d. tube was strikingly similar to partial hepatic ischemia in the pathophysiological profile during hepatic ischemia. PSS with a tube 1 mm or more in inner diameter offers pathophysiological advantages in experiments on THI and reperfusion. Copyright 1998 Academic Press.

  6. Borax partially prevents neurologic disability and oxidative stress in experimental spinal cord ischemia/reperfusion injury.

    Science.gov (United States)

    Koc, Emine Rabia; Gökce, Emre Cemal; Sönmez, Mehmet Akif; Namuslu, Mehmet; Gökce, Aysun; Bodur, A Said

    2015-01-01

    The aim of this study is to investigate the potential effects of borax on ischemia/reperfusion injury of the rat spinal cord. Twenty-one Wistar albino rats were divided into 3 groups: sham (no ischemia/reperfusion), ischemia/reperfusion, and borax (ischemia/reperfusion + borax); each group was consist of 7 animals. Infrarenal aortic cross clamp was applied for 30 minutes to generate spinal cord ischemia. Animals were evaluated functionally with the Basso, Beattie, and Bresnahan scoring system and inclined-plane test. The spinal cord tissue samples were harvested to analyze tissue concentrations of nitric oxide, nitric oxide synthase activity, xanthine oxidase activity, total antioxidant capacity, and total oxidant status and to perform histopathological examination. At the 72nd hour after ischemia, the borax group had significantly higher Basso, Beattie, and Bresnahan and inclined-plane scores than those of ischemia/reperfusion group. Histopathological examination of spinal cord tissues in borax group showed that treatment with borax significantly reduced the degree of spinal cord edema, inflammation, and tissue injury disclosed by light microscopy. Xanthine oxidase activity and total oxidant status levels of the ischemia/reperfusion group were significantly higher than those of the sham and borax groups (P borax group were significantly higher than those of the ischemia/reperfusion group (P borax groups in terms of total antioxidant capacity levels (P > .05). The nitric oxide levels and nitric oxide synthase activity of all groups were similar (P > .05). Borax treatment seems to protect the spinal cord against injury in a rat ischemia/reperfusion model and improve neurological outcome. Copyright © 2015 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  7. Unilateral Partial Nephrectomy with Warm Ischemia Results in Acute Hypoxia Inducible Factor 1-Alpha (HIF-1α and Toll-Like Receptor 4 (TLR4 Overexpression in a Porcine Model.

    Directory of Open Access Journals (Sweden)

    Zhiyong Zhang

    Full Text Available Ischemia/reperfusion (I/R during partial nephrectomy (PN contributes to acute kidney injury (AKI, which is inaccurately assessed using existent clinical markers of renal function. We evaluated I/R-related changes in expression in hypoxia inducible factor 1α (HIF-1α and toll-like receptor 4 (TLR4, within kidney tissue and peripheral blood leukocytes (PBL in a porcine model of PN.Three adult pigs each underwent unilateral renal hilar cross clamping for 180 min followed by a 15 min reperfusion. The contralateral kidney served as control. Biopsies of clamped kidneys were obtained at baseline (time 0, every 60 min during the hypoxic phase, and post-reperfusion. Control kidneys were biopsied once at 180 min. Peripheral blood was sampled at time 0, every 30 min during the hypoxic phase, and post-reperfusion. HIF-1α and TLR4 expression in kidney tissue and PBL were analyzed by Western blotting. I/R-related histological changes were assessed.Expression of HIF-1α in clamped kidneys and PBL was below detection level at baseline, rising to detectable levels after 60 min of hypoxia, and continuing to rise throughout the hypoxic and reperfusion phases. Expression of TLR-4 in clamped kidneys followed a similar trend with initial detection after 30-60 min of hypoxia. Control kidneys exhibited no change in HIF-1α or TLR-4 expression. I/R-related histologic changes were minimal, primarily mild tubular dilatation.In a porcine model of PN, HIF-1α and TLR4 exhibited robust, I/R-related increases in expression in kidney tissue and PBL. Further studies investigating these molecules as potential markers of AKI are warranted.

  8. Nonhuman primate models of focal cerebral ischemia

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    Jingjing Fan

    2017-01-01

    Full Text Available Rodents have been widely used in the production of cerebral ischemia models. However, successful therapies have been proven on experimental rodent stroke model, and they have often failed to be effective when tested clinically. Therefore, nonhuman primates were recommended as the ideal alternatives, owing to their similarities with the human cerebrovascular system, brain metabolism, grey to white matter ratio and even their rich behavioral repertoire. The present review is a thorough summary of ten methods that establish nonhuman primate models of focal cerebral ischemia; electrocoagulation, endothelin-1-induced occlusion, microvascular clip occlusion, autologous blood clot embolization, balloon inflation, microcatheter embolization, coil embolization, surgical suture embolization, suture, and photochemical induction methods. This review addresses the advantages and disadvantages of each method, as well as precautions for each model, compared nonhuman primates with rodents, different species of nonhuman primates and different modeling methods. Finally it discusses various factors that need to be considered when modelling and the method of evaluation after modelling. These are critical for understanding their respective strengths and weaknesses and underlie the selection of the optimum model.

  9. Mixed models in cerebral ischemia study

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    Matheus Henrique Dal Molin Ribeiro

    2016-06-01

    Full Text Available The data modeling from longitudinal studies stands out in the current scientific scenario, especially in the areas of health and biological sciences, which induces a correlation between measurements for the same observed unit. Thus, the modeling of the intra-individual dependency is required through the choice of a covariance structure that is able to receive and accommodate the sample variability. However, the lack of methodology for correlated data analysis may result in an increased occurrence of type I or type II errors and underestimate/overestimate the standard errors of the model estimates. In the present study, a Gaussian mixed model was adopted for the variable response latency of an experiment investigating the memory deficits in animals subjected to cerebral ischemia when treated with fish oil (FO. The model parameters estimation was based on maximum likelihood methods. Based on the restricted likelihood ratio test and information criteria, the autoregressive covariance matrix was adopted for errors. The diagnostic analyses for the model were satisfactory, since basic assumptions and results obtained corroborate with biological evidence; that is, the effectiveness of the FO treatment to alleviate the cognitive effects caused by cerebral ischemia was found.

  10. Partially ordered models

    NARCIS (Netherlands)

    Fernandez, R.; Deveaux, V.

    2010-01-01

    We provide a formal definition and study the basic properties of partially ordered chains (POC). These systems were proposed to model textures in image processing and to represent independence relations between random variables in statistics (in the later case they are known as Bayesian networks).

  11. Partially Hidden Markov Models

    DEFF Research Database (Denmark)

    Forchhammer, Søren Otto; Rissanen, Jorma

    1996-01-01

    Partially Hidden Markov Models (PHMM) are introduced. They differ from the ordinary HMM's in that both the transition probabilities of the hidden states and the output probabilities are conditioned on past observations. As an illustration they are applied to black and white image compression where...

  12. Partially composite Higgs models

    DEFF Research Database (Denmark)

    Alanne, Tommi; Buarque Franzosi, Diogo; Frandsen, Mads T.

    2018-01-01

    We study the phenomenology of partially composite-Higgs models where electroweak symmetry breaking is dynamically induced, and the Higgs is a mixture of a composite and an elementary state. The models considered have explicit realizations in terms of gauge-Yukawa theories with new strongly...... interacting fermions coupled to elementary scalars and allow for a very SM-like Higgs state. We study constraints on their parameter spaces from vacuum stability and perturbativity as well as from LHC results and find that requiring vacuum stability up to the compositeness scale already imposes relevant...... constraints. A small part of parameter space around the classically conformal limit is stable up to the Planck scale. This is however already strongly disfavored by LHC results. in different limits, the models realize both (partially) composite-Higgs and (bosonic) technicolor models and a dynamical extension...

  13. CSF transthyretin neuroprotection in a mouse model of brain ischemia

    DEFF Research Database (Denmark)

    Santos, Sofia Duque; Lambertsen, Kate Lykke; Clausen, Bettina Hjelm

    2010-01-01

    Brain injury caused by ischemia is a major cause of human mortality and physical/cognitive disability worldwide. Experimentally, brain ischemia can be induced surgically by permanent middle cerebral artery occlusion. Using this model, we studied the influence of transthyretin in ischemic stroke. ...

  14. The administration of renoprotective agents extends warm ischemia in a rat model.

    Science.gov (United States)

    Cohen, Jacob; Dorai, Thambi; Ding, Cheng; Batinic-Haberle, Ines; Grasso, Michael

    2013-03-01

    Extended warm ischemia time during partial nephrectomy leads to considerable renal injury. Using a rat model of renal ischemia, we examined the ability of a unique renoprotective cocktail to ameliorate warm ischemia-reperfusion injury and extend warm ischemia time. A warm renal ischemia model was developed using Sprague-Dawley rats, clamping the left renal artery for 40, 50, 60, and 70 minutes, followed by 48 hours of reperfusion. An improved renoprotective cocktail referred to as I-GPM (a mixture of specific renoprotective growth factors, porphyrins, and mitochondria-protecting amino acids) was administered -24 hours, 0 hours, and +24 hours after surgery. At 48 hours, both kidneys were harvested and examined with hematoxylin and eosin and periodic acid-Schiff stains for the analysis of renal tubular necrosis. Creatinine, protein, and gene expression levels were also analyzed to evaluate several ischemia-specific and antioxidant response markers. I-GPM treated kidneys showed significant reversal of morphologic changes and a significant reduction in specific ischemic markers lipocalin-2, galectin-3, GRP-78, and HMGB1 compared with ischemic controls. These experiments also showed an upregulation of the stress response protein, heat shock protein (HSP)-70, as well as the phosphorylated active form of the transcription factor, heat shock factor (HSF)-1. In addition, quantitative RT-PCR analyses revealed a robust upregulation of several antioxidant pathway response genes in I-GPM treated animals. By histopathologic and several molecular measures, our unique renoprotective cocktail mitigated ischemia-reperfusion injury. Our cocktail minimized oxidative stress in an ischemic kidney rat model while at the same time protecting the global parenchymal function during extended periods of ischemia.

  15. Anatomic renal artery branch microdissection to facilitate zero-ischemia partial nephrectomy.

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    Ng, Casey K; Gill, Inderbir S; Patil, Mukul B; Hung, Andrew J; Berger, Andre K; de Castro Abreu, Andre Luis; Nakamoto, Masahiko; Eisenberg, Manuel S; Ukimura, Osamu; Thangathurai, Duraiyah; Aron, Monish; Desai, Mihir M

    2012-01-01

    Robot-assisted and laparoscopic partial nephrectomies (PNs) for medial tumors are technically challenging even with the hilum clamped and, until now, were impossible to perform with the hilum unclamped. Evaluate whether targeted vascular microdissection (VMD) of renal artery branches allows zero-ischemia PN to be performed even for challenging medial tumors. A prospective cohort evaluation of 44 patients with renal masses who underwent robot-assisted or laparoscopic zero-ischemia PN either with anatomic VMD (group 1; n=22) or without anatomic VMD (group 2; n=22) performed by a single surgeon from April 2010 to January 2011. Zero-ischemia PN with VMD incorporates four maneuvers: (1) preoperative computed tomographic reconstruction of renal arterial branch anatomy, (2) anatomic dissection of targeted, tumor-specific tertiary or higher-order renal arterial branches, (3) neurosurgical aneurysm microsurgical bulldog clamp(s) for superselective tumor devascularization, and (4) transient, controlled reduction of blood pressure, if necessary. Baseline, perioperative, and postoperative data were collected prospectively. Group 1 tumors were larger (4.3 vs 2.6 cm; p=0.011), were more often hilar (41% vs 9%; p=0.09), were medial (59% and 23%; p=0.017), were closer to the hilum (1.46 vs 3.26 cm; p=0.0002), and had a lower C index score (2.1 vs 3.9; p=0.004) and higher RENAL nephrometry scores (7.7 vs 6.2; p=0.013). Despite greater complexity, no group 1 tumor required hilar clamping, and perioperative outcomes were similar to those of group 2: operating room time (4.7 and 4.1h), median blood loss (200 and 100ml), surgical margins for cancer (all negative), major complications (0% and 9%), and minor complications (18% and 14%). The median serum creatinine level was similar 2 mo postoperatively (1.2 and 1.3mg/dl). The study was limited by the relatively small sample size. Anatomic targeted dissection and superselective control of tumor-specific renal arterial branches facilitate

  16. Superior mesenteric arterial branch occlusion causing partial jejunal ischemia: a case report

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    Van De Winkel Nele

    2012-02-01

    Full Text Available Abstract Introduction Ischemic bowel disease comprises both mesenteric ischemia and colonic ischemia. Mesenteric ischemia can be divided into acute and chronic ischemia. These are two separate entities, each with their specific clinical presentation and diagnostic and therapeutic modalities. However, diagnosis may be difficult due to the vague symptomatology and subtle signs. Case presentation We report the case of a 68-year-old Caucasian woman who presented with abdominal discomfort, anorexia, melena and fever. A physical examination revealed left lower quadrant tenderness and an irregular pulse. Computed tomography of her abdomen as well as computed tomography enterography, enteroscopy, angiography and small bowel enteroclysis demonstrated an ischemic jejunal segment caused by occlusion of a branch of the superior mesenteric artery. The ischemic segment was resected and an end-to-end anastomosis was performed. The diagnosis of segmental small bowel ischemia was confirmed by histopathological study. Conclusion Mesenteric ischemia is a pathology well-known by surgeons, gastroenterologists and radiologists. Acute and chronic mesenteric ischemia are two separate entities with their own specific clinical presentation, radiological signs and therapeutic modalities. We present the case of a patient with symptoms and signs of chronic mesenteric ischemia despite an acute etiology. To the best of our knowledge, this is the first report presenting a case of acute mesenteric ischemia with segmental superior mesenteric artery occlusion.

  17. Memantine mediates neuroprotection via regulating neurovascular unit in a mouse model of focal cerebral ischemia.

    Science.gov (United States)

    Chen, Zheng-Zhen; Yang, Dan-Dan; Zhao, Zhan; Yan, Hui; Ji, Juan; Sun, Xiu-Lan

    2016-04-01

    Memantine is a low-moderate affinity and uncompetitive N-methyl-d-aspartate receptor (NMDAR) antagonist, which is also a potential neuroprotectant in acute ischemic stroke for its particular action profiles. The present study was to reveal the mechanisms involved in the neuroprotection of memantine. We used a mouse model of permanent focal cerebral ischemia via middle cerebral artery occlusion to verify our hypothesis. 2,3,5-Triphenyltetrazolium chloride staining was used to compare infarct size. The amount of astrocytes and the somal volume of the microglia cell body were analyzed by immunohistochemistry and stereological estimates. Western blotting was used to determine the protein expressions. Memantine prevented cerebral ischemia-induced brain infarct and neuronal injury, and reduced oxygen-glucose deprivation-induced cortical neuronal apoptosis. Moreover, memantine reduced the amount of the damaged astrocytes and over activated microglia after 24h of ischemia. In the early phase of ischemia, higher production of MMP-9 was observed, and thereby collagen IV was dramatically disrupted. Meanwhile, the post-synaptic density protein 95(PSD-95) was also severely cleavaged. Memantine decreased MMP-9 secretion, prevented the degradation of collagen IV in mouse brain. PSD-95 cleavage was also inhibited by memantine. These results suggested that memantine exerted neuroprotection effects in acute ischemic brain damage, partially via improving the functions of neurovascular unit. Taking all these findings together, we consider that memantine might be a promising protective agent against ischemic stroke. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Optical fluorescence spectroscopy to detect hepatic necrosis after normothermic ischemia: animal model

    Science.gov (United States)

    Romano, Renan A.; Vollet-Filho, Jose D.; Pratavieira, Sebastião.; Fernandez, Jorge L.; Kurachi, Cristina; Bagnato, Vanderlei S.; Castro-e-Silva, Orlando; Sankarankutty, Ajith K.

    2015-06-01

    Liver transplantation is a well-established treatment for liver failure. However, the success of the transplantation procedure depends on liver graft conditions. The tissue function evaluation during the several transplantation stages is relevant, in particular during the organ harvesting, when a decision is made concerning the viability of the graft. Optical fluorescence spectroscopy is a good option because it is a noninvasive and fast technique. A partial normothermic hepatic ischemia was performed in rat livers, with a vascular occlusion of both median and left lateral lobes, allowing circulation only for the right lateral lobe and the caudate lobe. Fluorescence spectra under excitation at 532 nm (doubled frequency Nd:YAG laser) were collected using a portable spectrometer (USB2000, Ocean Optics, USA). The fluorescence emission was collected before vascular occlusion, after ischemia, and 24 hours after reperfusion. A morphometric histology analysis was performed as the gold standard evaluation - liver samples were analyzed, and the percentage of necrotic tissue was obtained. The results showed that changes in the fluorescence emission after ischemia can be correlated with the amount of necrosis evaluated by a morphometric analysis, the Pearson correlation coefficient of the generated model was 0.90 and the root mean square error was around 20%. In this context, the laser-induced fluorescence spectroscopy technique after normothermic ischemia showed to be a fast and efficient method to differentiate ischemic injury from viable tissues.

  19. Robotic unclamped "minimal-margin" partial nephrectomy: ongoing refinement of the anatomic zero-ischemia concept.

    Science.gov (United States)

    Satkunasivam, Raj; Tsai, Sheaumei; Syan, Sumeet; Bernhard, Jean-Christophe; de Castro Abreu, Andre Luis; Chopra, Sameer; Berger, Andre K; Lee, Dennis; Hung, Andrew J; Cai, Jie; Desai, Mihir M; Gill, Inderbir S

    2015-10-01

    Anatomic partial nephrectomy (PN) techniques aim to decrease or eliminate global renal ischemia. To report the technical feasibility of completely unclamped "minimal-margin" robotic PN. We also illustrate the stepwise evolution of anatomic PN surgery with related outcomes data. This study was a retrospective analysis of 179 contemporary patients undergoing anatomic PN at a tertiary academic institution between October 2009 and February 2013. Consecutive consented patients were grouped into three cohorts: group 1, with superselective clamping and developmental-curve experience (n = 70); group 2, with superselective clamping and mature experience (n = 60); and group 3, which had completely unclamped, minimal-margin PN (n = 49). Patients in groups 1 and 2 underwent superselective tumor-specific devascularization, whereas patients in group 3 underwent completely unclamped minimal-margin PN adjacent to the tumor edge, a technique that takes advantage of the radially oriented intrarenal architecture and anatomy. Primary outcomes assessed the technical feasibility of robotic, completely unclamped, minimal-margin PN; short-term changes in estimated glomerular filtration rate (eGFR); and development of new-onset chronic kidney disease (CKD) stage >3. Secondary outcome measures included perioperative variables, 30-d complications, and histopathologic outcomes. Demographic data were similar among groups. For similarly sized tumors (p = 0.13), percentage of kidney preserved was greater (p = 0.047) and margin width was narrower (p = 0.0004) in group 3. In addition, group 3 had less blood loss (200, 225, and 150ml; p = 0.04), lower transfusion rates (21%, 23%, and 4%; p = 0.008), and shorter hospital stay (p = 0.006), whereas operative time and 30-d complication rates were similar. At 1-mo postoperatively, median percentage reduction in eGFR was similar (7.6%, 0%, and 3.0%; p = 0.53); however, new-onset CKD stage >3 occurred less frequently in group 3 (23%, 10%, and 2%; p = 0

  20. Adaptive Partially Hidden Markov Models

    DEFF Research Database (Denmark)

    Forchhammer, Søren Otto; Rasmussen, Tage

    1996-01-01

    Partially Hidden Markov Models (PHMM) have recently been introduced. The transition and emission probabilities are conditioned on the past. In this report, the PHMM is extended with a multiple token version. The different versions of the PHMM are applied to bi-level image coding....

  1. Partially molten magma ocean model

    International Nuclear Information System (INIS)

    Shirley, D.N.

    1983-01-01

    The properties of the lunar crust and upper mantle can be explained if the outer 300-400 km of the moon was initially only partially molten rather than fully molten. The top of the partially molten region contained about 20% melt and decreased to 0% at 300-400 km depth. Nuclei of anorthositic crust formed over localized bodies of magma segregated from the partial melt, then grew peripherally until they coverd the moon. Throughout most of its growth period the anorthosite crust floated on a layer of magma a few km thick. The thickness of this layer is regulated by the opposing forces of loss of material by fractional crystallization and addition of magma from the partial melt below. Concentrations of Sr, Eu, and Sm in pristine ferroan anorthosites are found to be consistent with this model, as are trends for the ferroan anorthosites and Mg-rich suites on a diagram of An in plagioclase vs. mg in mafics. Clustering of Eu, Sr, and mg values found among pristine ferroan anorthosites are predicted by this model

  2. Mathematical Modeling of Ischemia-Reperfusion Injury and Postconditioning Therapy.

    Science.gov (United States)

    Fong, D; Cummings, L J

    2017-11-01

    Reperfusion (restoration of blood flow) after a period of ischemia (interruption of blood flow) can paradoxically place tissues at risk of further injury: so-called ischemia-reperfusion injury or IR injury. Recent studies have shown that postconditioning (intermittent periods of further ischemia applied during reperfusion) can reduce IR injury. We develop a mathematical model to describe the reperfusion and postconditioning process following an ischemic insult, treating the blood vessel as a two-dimensional channel, lined with a monolayer of endothelial cells that interact (respiration and mechanotransduction) with the blood flow. We investigate how postconditioning affects the total cell density within the endothelial layer, by varying the frequency of the pulsatile flow and the oxygen concentration at the inflow boundary. We find that, in the scenarios we consider, the pulsatile flow should be of high frequency to minimize cellular damage, while oxygen concentration at the inflow boundary should be held constant, or subject to only low-frequency variations, to maximize cell proliferation.

  3. Perinatal Hypoxia and Ischemia in Animal Models of Schizophrenia

    Directory of Open Access Journals (Sweden)

    Dimitri Hefter

    2018-03-01

    Full Text Available Intrauterine or perinatal complications constitute a major risk for psychiatric diseases. Infants who suffered from hypoxia–ischemia (HI are at twofold risk to develop schizophrenia in later life. Several animal models attempt to reproduce these complications to study the yet unknown steps between an insult in early life and outbreak of the disease decades later. However, it is very challenging to find the right type and severity of insult leading to a disease-like phenotype in the animal, but not causing necrosis and focal neurological deficits. By contrast, too mild, repetitive insults may even be protective via conditioning effects. Thus, it is not surprising that animal models of hypoxia lead to mixed results. To achieve clinically translatable findings, better protocols are urgently needed. Therefore, we compare widely used models of hypoxia and HI and propose future directions for the field.

  4. Gaseous hydrogen sulfide protects against myocardial ischemia-reperfusion injury in mice partially independent from hypometabolism.

    Directory of Open Access Journals (Sweden)

    Pauline M Snijder

    Full Text Available BACKGROUND: Ischemia-reperfusion injury (IRI is a major cause of cardiac damage following various pathological processes. Gaseous hydrogen sulfide (H2S is protective during IRI by inducing a hypometabolic state in mice which is associated with anti-apoptotic, anti-inflammatory and antioxidant properties. We investigated whether gaseous H2S administration is protective in cardiac IRI and whether non-hypometabolic concentrations of H2S have similar protective properties. METHODS: Male C57BL/6 mice received a 0, 10, or 100 ppm H2S-N2 mixture starting 30 minutes prior to ischemia until 5 minutes pre-reperfusion. IRI was inflicted by temporary ligation of the left coronary artery for 30 minutes. High-resolution respirometry equipment was used to assess CO2-production and blood pressure was measured using internal transmitters. The effects of H2S were assessed by histological and molecular analysis. RESULTS: Treatment with 100 ppm H2S decreased CO2-production by 72%, blood pressure by 14% and heart rate by 25%, while treatment with 10 ppm H2S had no effects. At day 1 of reperfusion 10 ppm H2S showed no effect on necrosis, while treatment with 100 ppm H2S reduced necrosis by 62% (p<0.05. Seven days post-reperfusion, both 10 ppm (p<0.01 and 100 ppm (p<0.05 H2S showed a reduction in fibrosis compared to IRI animals. Both 10 ppm and 100 ppm H2S reduced granulocyte-influx by 43% (p<0.05 and 60% (p<0.001, respectively. At 7 days post-reperfusion both 10 and 100 ppm H2S reduced expression of fibronectin by 63% (p<0.05 and 67% (p<0.01 and ANP by 84% and 63% (p<0.05, respectively. CONCLUSIONS: Gaseous administration of H2S is protective when administered during a cardiac ischemic insult. Although hypometabolism is restricted to small animals, we now showed that low non-hypometabolic concentrations of H2S also have protective properties in IRI. Since IRI is a frequent cause of myocardial damage during percutaneous coronary intervention and cardiac

  5. Mathematical Modelling of Intraretinal Oxygen Partial Pressure ...

    African Journals Online (AJOL)

    Purpose: The aim of our present work is to develop a simple steady state model for intraretinal oxygen partial pressure distribution and to investigate the effect of various model parameters on the partial pressure distribution under adapted conditions of light and darkness.. Method: A simple eight-layered mathematical model ...

  6. Partially Observed Mixtures of IRT Models: An Extension of the Generalized Partial-Credit Model

    Science.gov (United States)

    Von Davier, Matthias; Yamamoto, Kentaro

    2004-01-01

    The generalized partial-credit model (GPCM) is used frequently in educational testing and in large-scale assessments for analyzing polytomous data. Special cases of the generalized partial-credit model are the partial-credit model--or Rasch model for ordinal data--and the two parameter logistic (2PL) model. This article extends the GPCM to the…

  7. Development of a mouse model of neuropathic pain following photochemically induced ischemia in the sciatic nerve.

    Science.gov (United States)

    Hao, J X; Blakeman, K H; Yu, W; Hultenby, K; Xu, X J; Wiesenfeld-Hallin, Z

    2000-05-01

    A mouse model of neuropathic pain was developed by a photochemically induced ischemic nerve injury in normal male C57/BL6 mice. The ischemia was induced by unilateral irradiation of the sciatic nerve with an argon ion laser after intravenous administration of a photosensitizing dye, erythrosin B. The nerve injury resulted in a significant decrease in withdrawal threshold of the hindpaws to mechanical stimulation with von Frey hairs, as well as increased responsiveness to cold and heat stimulation. The mice, however, did not exhibit overt spontaneous pain-like behaviors. The evoked pain-related behaviors were observed bilaterally, although the ipsilateral changes were greater than on the contralateral side. The extent and time course of the behavioral changes were related to the duration of laser irradiation, with 1-min exposure producing the most consistent effect. Morphological examination at the light microscopic level revealed partial demyelination and axonal degeneration of the large myelinated fibers at the epicenter of the lesion 1 week postirradiation. The extent of the damage was correlated with the duration of irradiation. Injury and loss of unmyelinated fibers were also observed at the electronmicroscopic level. We conclude that an intravascular photochemical reaction leading to ischemia results in graded damage to the sciatic nerve in mice. Moreover, the nerve injury is associated with the development of abnormal pain-related behaviors. Both the behavioral and the morphological changes are correlated with the duration of irradiation. These results establish a mouse model of partial nerve injury with neuropathic pain-like behaviors which may be useful in studies using genetically modified mice. Copyright 2000 Academic Press.

  8. PARP Inhibition Attenuates Histopathological Lesion in Ischemia/Reperfusion Renal Mouse Model after Cold Prolonged Ischemia

    Directory of Open Access Journals (Sweden)

    Raimundo M. G. del Moral

    2013-01-01

    Full Text Available We test the hypothesis that PARP inhibition can decrease acute tubular necrosis (ATN and other renal lesions related to prolonged cold ischemia/reperfusion (IR in kidneys preserved at 4°C in University of Wisconsin (UW solution. Material and Methods. We used 30 male Parp1+/+ wild-type and 15 male Parp10/0 knockout C57BL/6 mice. Fifteen of these wild-type mice were pretreated with 3,4-dihydro-5-[4-(1-piperidinylbutoxyl]-1(2H-isoquinolinone (DPQ at a concentration of 15 mg/kg body weight, used as PARP inhibitor. Subgroups of mice were established (A: IR 45 min/6 h; B: IR + 48 h in UW solution; and C: IR + 48 h in UW solution plus DPQ. We processed samples for morphological, immunohistochemical, ultrastructural, and western-blotting studies. Results. Prolonged cold ischemia time in UW solution increased PARP-1 expression and kidney injury. Preconditioning with PARP inhibitor DPQ plus DPQ supplementation in UW solution decreased PARP-1 nuclear expression in renal tubules and renal damage. Parp10/0 knockout mice were more resistant to IR-induced renal lesion. In conclusion, PARP inhibition attenuates ATN and other IR-related renal lesions in mouse kidneys under prolonged cold storage in UW solution. If confirmed, these data suggest that pharmacological manipulation of PARP activity may have salutary effects in cold-stored organs at transplantation.

  9. Statistical modeling of the mother-baby system in newborn infants with cerebral ischemia

    Directory of Open Access Journals (Sweden)

    A. V. Filonenko

    2014-01-01

    Full Text Available The statistical model could consider the influence of specific maternal psychoemotional and personality factors on a newborn with cerebral ischemia and develop a procedure to prevent negative consequences of postpartum depression in the mother-baby system.

  10. A Model of Ischemia-Induced Neuroblast Activation in the Adult Subventricular Zone

    OpenAIRE

    Vergni, Davide; Castiglione, Filippo; Briani, Maya; Middei, Silvia; Alberdi, Elena; Reymann, Klaus G.; Natalini, Roberto; Volont?, Cinzia; Matute, Carlos; Cavaliere, Fabio

    2009-01-01

    12 p. We have developed a rat brain organotypic culture model, in which tissue slices contain cortex-subventricular zone-striatum regions, to model neuroblast activity in response to in vitro ischemia. Neuroblast activation has been described in terms of two main parameters, proliferation and migration from the subventricular zone into the injured cortex. We observed distinct phases of neuroblast activation as is known to occur after in vivo ischemia. Thus, immediately after oxygen/glucose...

  11. Some Considerations on the Partial Credit Model

    Science.gov (United States)

    Verhelst, N. D.; Verstralen, H. H. F. M.

    2008-01-01

    The Partial Credit Model (PCM) is sometimes interpreted as a model for stepwise solution of polytomously scored items, where the item parameters are interpreted as difficulties of the steps. It is argued that this interpretation is not justified. A model for stepwise solution is discussed. It is shown that the PCM is suited to model sums of binary…

  12. A Model for Partial Kantian Cooperation

    OpenAIRE

    Kordonis, Ioannis

    2016-01-01

    This work presents a game theoretic model to describe game situations in which there is a partial cooperation among the players. Specifically, we assume that the players partially follow Kant's "Categorical Imperative". The model is stated for games with a continuum of players and the basic assumption made is that the participants consider that they belong to virtual groups in which they optimize their actions as if they were bound to follow the same strategy. The relation with the Nash, (Ben...

  13. Impact of warm ischemia time on the change of split renal function after minimally invasive partial nephrectomy in Taiwanese patients

    Directory of Open Access Journals (Sweden)

    Hung-Keng Li

    2015-01-01

    Conclusion: SRF is more sensitive for postoperative follow-up than eGFR. Longer warm ischemia time is associated with poorer postoperative renal function. RPN is a safe and feasible alternative to LPN.

  14. Partial Differential Equations Modeling and Numerical Simulation

    CERN Document Server

    Glowinski, Roland

    2008-01-01

    This book is dedicated to Olivier Pironneau. For more than 250 years partial differential equations have been clearly the most important tool available to mankind in order to understand a large variety of phenomena, natural at first and then those originating from human activity and technological development. Mechanics, physics and their engineering applications were the first to benefit from the impact of partial differential equations on modeling and design, but a little less than a century ago the Schrödinger equation was the key opening the door to the application of partial differential equations to quantum chemistry, for small atomic and molecular systems at first, but then for systems of fast growing complexity. Mathematical modeling methods based on partial differential equations form an important part of contemporary science and are widely used in engineering and scientific applications. In this book several experts in this field present their latest results and discuss trends in the numerical analy...

  15. Organotypic lung culture: A new model for studying ischemia and ex vivo perfusion in lung transplantation.

    Science.gov (United States)

    Baste, Jean-Marc; Gay, Arnaud; Smail, Hassiba; Noël, Romain; Bubenheim, Michael; Begueret, Hugues; Morin, Jean-Paul; Litzler, Pierre-Yves

    2015-01-01

    Donors after cardiac death (DCD) in lung transplantation is considered as a solution for organ shortage. However, it is characterized by warm ischemic period, which could be involved in severe Ischemia-Reperfusion lesion (IR) with early graft dysfunction. We describe a new hybrid model combining in vivo ischemia followed by in vitro reoxygenation using organ-specific culture. A hybrid model using in vivo ischemic period followed by in vitro lung slice reoxygenation was set up in rat to mimic DCD in lung transplantation with in vitro perfusion. Different markers (bioenergetics, oxidant stress assays, and histology) were measured to evaluate the viability of lung tissue after different ischemic times (I-0, I-1, I-2, I-4, I-15 hours) and reoxygenation times (R-0, R-1, R-4, R-24 hours). No differences were found in cell viability, ATP concentrations, extracellular LDH assays or histology, demonstrating extensive viability of up to 4 hours in lung tissue warm ischemia. We found oxidative stress mainly during the ischemic period with no burst at reoxygenation. Cytosolic anti-oxidant system was involved first (I-0,I-1,I-2) followed by mitochondrial anti-oxidant system for extensive ischemia (I-4). Histological features showed differences in this model of ischemia-reoxygenation between bronchial epithelium and lung parenchymal cells, with epithelium regeneration after 2 hours of warm ischemia and 24 hours of perfusion. The results of our hybrid model experiment suggest extensive lung viability of up to 4 hours ischemia. Our model could be an interesting tool to evaluate ex vivo reconditioning techniques after different in vivo lung insults.

  16. Effect of total flavonoids of Radix Ilicis pubescentis on cerebral ischemia reperfusion model

    Directory of Open Access Journals (Sweden)

    Xiaoli Yan

    2017-03-01

    Full Text Available This paper aims to observe the effects of total flavonoids of Radix Ilicis pubescentis on mouse model of cerebral ischemia reperfusion. Mice were orally given different doses of total flavonoids of Radix Ilicis pubescentis 10 d, and were administered once daily. On the tenth day after the administration of 1 h in mice after anesthesia, we used needle to hook the bilateral common carotid artery (CCA for 10 min, with 10 min ischemia reperfusion, 10 min ischemia. Then we restored their blood supply, copy the model of cerebral ischemia reperfusion; We then had all mice reperfused for 24 h, and then took their orbital blood samples and measured blood rheology. We quickly removed the brain, with half of the brain having sagittal incision. Then we fixed the brains and sectioned them to observe the pathological changes of brain cells in the hippocampus and cortex. We also measured the other half sample which was made of brain homogenate of NO, NOS, Na+-K+-, ATP enzyme Mg2+-ATPase and Ca2+-ATPase. Acupuncture needle hook occlusion of bilateral common carotid arteries can successfully establish the model of cerebral ischemia reperfusion. After comparing with the model mice, we concluded that Ilex pubescens flavonoids not only reduce damage to the brain nerve cells in the hippocampus and cortex, but also significantly reduce the content of NO in brain homogenate, the activity of nitric oxide synthase (NOS and increases ATP enzyme activity (P < 0.05, P < 0.01. In this way, cerebral ischemia reperfusion injury is improved. Different dosages of Ilex pubescens flavonoids on mouse cerebral ischemia reperfusion model have good effects.

  17. Testing the generalized partial credit model

    NARCIS (Netherlands)

    Glas, Cornelis A.W.

    1996-01-01

    The partial credit model (PCM) (G.N. Masters, 1982) can be viewed as a generalization of the Rasch model for dichotomous items to the case of polytomous items. In many cases, the PCM is too restrictive to fit the data. Several generalizations of the PCM have been proposed. In this paper, a

  18. Some Considerations on the Partial Credit Model

    OpenAIRE

    H.H.F.M. Verstralen; N.D. Verhelst

    2008-01-01

    The Partial Credit Model (PCM) is sometimes interpreted as a model for stepwise solution of polytomously scored items, where the item parameters are interpreted as di culties of the steps. It is argued that this interpretation is not justi ed. A model for stepwise solution is discussed. It is shown that the PCM is suited to model sums of binary responses which are not supposed to be stochastically independent. As a practical result, a statistical test of sto...

  19. Experimental study of pulmonary thromboembolism ischemia-reperfusion injury in canine model

    International Nuclear Information System (INIS)

    Li Jianjun; Zhai Renyou; Zhang Dongpo; Huang Qiang; Yu Ping; Dai Dingke; Bao Na

    2009-01-01

    Objective: To establish a canine model of pulmonary thromboembolism ischemia- reperfusion injury (PTE IRI) that may be used for imaging study. Methods: Ten male and 10 female healthy mongrel canines with (18.6±0.8) kg/body weight, were used. A Swan-Ganz catheter was introduced into the right internal jugular vein via a preset percutaneous sheath using the Seldinger technique, and then was with further insertion the pulmonary artery. Balloon occlusion of the right inferior lobe pulmonary artery for 4 hours was followed by removing the catheter and ending with 4 hours of reperfusion. CT was performed before ischemia, 4 h after ischemia and 4 h after reperfusion. At last, dogs were killed and the bilateral inferior lung tissues were prepared for the examination by light and electronic microscopy. Results: All canine models were successfully developed pulmonary thromboembolism ischemia-reperfusion injury. The examination of CT, light and electron microscopy consistently indicated the presence of permeability pulmonary edema after reperfusion. Conclusions: A closed-chest canine model in vivo of pulmonary thromboembolism ischemia-reperfusion injury can be established with virtual pathophysiological process in human and be as well as for imaging experimental study. (authors)

  20. Response Styles in the Partial Credit Model

    OpenAIRE

    Tutz, Gerhard; Schauberger, Gunther; Berger, Moritz

    2016-01-01

    In the modelling of ordinal responses in psychological measurement and survey- based research, response styles that represent specific answering patterns of respondents are typically ignored. One consequence is that estimates of item parameters can be poor and considerably biased. The focus here is on the modelling of a tendency to extreme or middle categories. An extension of the Partial Credit Model is proposed that explicitly accounts for this specific response style. In contrast to exi...

  1. Neuroprotective effects of SMADs in a rat model of cerebral ischemia/reperfusion

    Directory of Open Access Journals (Sweden)

    Fang-fang Liu

    2015-01-01

    Full Text Available Previous studies have shown that up-regulation of transforming growth factor β1 results in neuroprotective effects. However, the role of the transforming growth factor β1 downstream molecule, SMAD2/3, following ischemia/reperfusion remains unclear. Here, we investigated the neuroprotective effects of SMAD2/3 by analyzing the relationships between SMAD2/3 expression and cell apoptosis and inflammation in the brain of a rat model of cerebral ischemia/reperfusion. Levels of SMAD2/3 mRNA were up-regulated in the ischemic penumbra 6 hours after cerebral ischemia/reperfusion, reached a peak after 72 hours and were then decreased at 7 days. Phosphorylated SMAD2/3 protein levels at the aforementioned time points were consistent with the mRNA levels. Over-expression of SMAD3 in the brains of the ischemia/reperfusion model rats via delivery of an adeno-associated virus containing the SMAD3 gene could reduce tumor necrosis factor-α and interleukin-1β mRNA levels, down-regulate expression of the pro-apoptotic gene, capase-3, and up-regulate expression of the anti-apoptotic protein, Bcl-2. The SMAD3 protein level was negatively correlated with cell apoptosis. These findings indicate that SMAD3 exhibits neuroprotective effects on the brain after ischemia/reperfusion through anti-inflammatory and anti-apoptotic pathways.

  2. Partial chord diagrams and matrix models

    DEFF Research Database (Denmark)

    Andersen, Jørgen Ellegaard; Fuji, Hiroyuki; Manabe, Masahide

    In this article, the enumeration of partial chord diagrams is discussed via matrix model techniques. In addition to the basic data such as the number of backbones and chords, we also consider the Euler characteristic, the backbone spectrum, the boundary point spectrum, and the boundary length spe...

  3. The influence of stachydrine hydrochloride on the reperfusion model of mice with repetitive cerebral ischemia

    Directory of Open Access Journals (Sweden)

    Mingsan Miao

    2017-03-01

    Full Text Available To study the influence of stachydrine hydrochloride on the inflammatory cytokines and tissue morphology of the re-perfusion model of mice with repetitive cerebral ischemia and probe into the protection mechanism of stachydrine hydrochloride for cerebral ischemia reperfusion impairment. Build a repetitive cerebral ischemia reperfusion model by first blocking the common carotid artery on both sides for 10 min, then resuming perfusion for 10 min and then blocking the common carotid artery on both sides again for 10 min. Before the operation, all the mice in the Nimodipine group, and the big, medium and small stachydrine hydrochloride dose groups were given corresponding gastric perfusion, the mice in the sham operation group and the modeled groups were at the same time given 0.5% sodium carboxymethyl cellulose for gastric perfusion of the same volume. The medicine was fed daily for 7 consecutive days. The model was built 1 h after the last feed and the perfusion continued for 24 h after the operation. Then the death rate of the mice was calculated. The mouse brains were taken out to test the ICAM-1 level and the TNF-α level, and the serum was taken out to test the NSE level and the MPO level. The tissue morphology changes were also observed. All the repetitive cerebral ischemia reperfusion models were successfully duplicated. The stachydrine hydrochloride in all the dose groups significantly reduced the death rates of big and small mice, reduced the level of ICAM-1 and the level of TNF-α in the brain tissues and the NSE level and the MPO level in the serum, significantly alleviating the pathological impairment in the hippocampus. Stachydrine hydrochloride can significantly reduce the death rate of mice, improve the pathological changes in the hippocampus, inhibit inflammatory reactions after ischemia, thus reducing the re-perfusion impairment after cerebral ischemia.

  4. Some Considerations on the Partial Credit Model

    Directory of Open Access Journals (Sweden)

    H.H.F.M. Verstralen

    2008-01-01

    Full Text Available The Partial Credit Model (PCM is sometimes interpreted as a model for stepwise solution of polytomously scored items, where the item parameters are interpreted as di culties of the steps. It is argued that this interpretation is not justi ed. A model for stepwise solution is discussed. It is shown that the PCM is suited to model sums of binary responses which are not supposed to be stochastically independent. As a practical result, a statistical test of stochastic independence in the Rasch model is derived

  5. Neuroprotective effects of riluzole: an electrophysiological and histological analysis in an in vitro model of ischemia.

    Science.gov (United States)

    Siniscalchi, A; Zona, C; Sancesario, G; D'Angelo, E; Zeng, Y C; Mercuri, N B; Bernardi, G

    1999-06-01

    The protective effects of riluzole against the neuronal damage caused by O2 and glucose deprivation (ischemia) was investigated in rat cortical slices by recording electrophysiologically the cortico-cortical field potential and by evaluating histologically the severity of neuronal death. Five minutes of ischemia determined an irreversible depression of the amplitude of the field potential. In addition, this insult caused a clear enhancement of the number of death cells that were specifically colored with trypan blue (a vital colorant which stains altered cells). We found that riluzole, which by itself depressed the synaptic transmission, neuroprotected when perfused 15-20 min before and during ischemia. In fact, due to the treatment with riluzole, the ischemia-induced irreversible depression of the field potential recovered and less cells were stained with trypan blue. These findings demonstrate that riluzole prevents neuronal death in an in vitro model of ischemia and suggest a therapeutic use of this drug in order to reduce the pathophysiological outcomes of stroke.

  6. Imaging of acute mesenteric ischemia using multidetector CT and CT angiography in a porcine model.

    Science.gov (United States)

    Rosow, David E; Sahani, Dushyant; Strobel, Oliver; Kalva, Sanjeeva; Mino-Kenudson, Mari; Holalkere, Nagaraj S; Alsfasser, Guido; Saini, Sanjay; Lee, Susanna I; Mueller, Peter R; Fernández-del Castillo, Carlos; Warshaw, Andrew L; Thayer, Sarah P

    2005-12-01

    Acute mesenteric ischemia, a frequently lethal disease, requires prompt diagnosis and intervention for favorable clinical outcomes. This goal remains elusive due, in part, to lack of a noninvasive and accurate imaging study. Traditional angiography is the diagnostic gold standard but is invasive and costly. Computed tomography (CT) is readily available and noninvasive but has shown variable success in diagnosing this disease. The faster scanning time of multidetector row CT (M.D.CT) greatly facilitates the use of CT angiography (CTA) in the clinical setting. We sought to determine whether M.D.CT-CTA could accurately demonstrate vascular anatomy and capture the earliest stages of mesenteric ischemia in a porcine model. Pigs underwent embolization of branches of the superior mesenteric artery, then imaging by M.D.CT-CTA with three-dimensional reconstruction protocols. After scanning, diseased bowel segments were surgically resected and pathologically examined. Multidetector row CT and CT angiography reliably defined normal and occluded mesenteric vessels in the pig. It detected early changes of ischemia including poor arterial enhancement and venous dilatation, which were seen in all ischemic animals. The radiographic findings--compared with pathologic diagnoses-- predicted ischemia, with a positive predictive value of 92%. These results indicate that M.D.CT-CTA holds great promise for the early detection necessary for successful treatment of acute mesenteric ischemia.

  7. Disruption of the Serotonergic System after Neonatal Hypoxia-Ischemia in a Rodent Model

    Directory of Open Access Journals (Sweden)

    Kathryn M. Buller

    2012-01-01

    Full Text Available Identifying which specific neuronal phenotypes are vulnerable to neonatal hypoxia-ischemia, where in the brain they are damaged, and the mechanisms that produce neuronal losses are critical to determine the anatomical substrates responsible for neurological impairments in hypoxic-ischemic brain-injured neonates. Here we describe our current work investigating how the serotonergic network in the brain is disrupted in a rodent model of preterm hypoxia-ischemia. One week after postnatal day 3 hypoxia-ischemia, losses of serotonergic raphé neurons, reductions in serotonin levels in the brain, and reduced serotonin transporter expression are evident. These changes can be prevented using two anti-inflammatory interventions; the postinsult administration of minocycline or ibuprofen. However, each drug has its own limitations and benefits for use in neonates to stem damage to the serotonergic network after hypoxia-ischemia. By understanding the fundamental mechanisms underpinning hypoxia-ischemia-induced serotonergic damage we will hopefully move closer to developing a successful clinical intervention to treat neonatal brain injury.

  8. Testing the generalized partial credit model

    OpenAIRE

    Glas, Cornelis A.W.

    1996-01-01

    The partial credit model (PCM) (G.N. Masters, 1982) can be viewed as a generalization of the Rasch model for dichotomous items to the case of polytomous items. In many cases, the PCM is too restrictive to fit the data. Several generalizations of the PCM have been proposed. In this paper, a generalization of the PCM (GPCM), a further generalization of the one-parameter logistic model, is discussed. The model is defined and the conditional maximum likelihood procedure for the method is describe...

  9. Curcumin reverses neurochemical, histological and immuno-histochemical alterations in the model of global brain ischemia

    Directory of Open Access Journals (Sweden)

    Glaura Fernandes Teixeira de Alcântara

    2017-01-01

    Full Text Available Curcumin, a curcuminoid from Curcuma longa, presents antioxidant and anti-inflammatory actions and, among pathological changes of cerebral ischemic injury, inflammation is an important one. The objectives were to study the neuroprotective action of curcumin, in a model of global ischemia. Male Wistar rats (sham-operated, ischemic untreated and ischemic treated with curcumin, 25 or 50 mg/kg, p.o. were anesthesized and their carotid arteries occluded, for 30 min. The SO group had the same procedure, except for carotid occlusion. In the 1st protocol, animals were treated 1 h before ischemia and 24 h later; and in the 2nd protocol, treatments began 1 h before ischemia, continuing for 7 days. Twenty four hours after the last administration, animals were euthanized and measurements for striatal monoamines were performed, at the 1st and 7th days after ischemia, as well as histological and immunohistochemical assays in hippocampi. We showed in both protocols, depletions of DA and its metabolites (DOPAC and HVA, in the ischemic group, but these effects were reversed by curcumin. Additionally, a decrease seen in 5-HT contents, 1 day after ischemia, was also reversed by curcumin. This reversion was not seen 7 days later. On the other hand, a decrease observed in NE levels, at the 7th day, was totally reversed by curcumin. Furthermore, curcumin treatments increased neuronal viability and attenuated the immunoreactivity for COX-2 and TNF-alpha, in the hippocampus in both protocols. We showed that curcumin exerts neuroprotective actions, in a model of brain ischemia that are probably related to its anti-inflammatory activity.

  10. Cofilin Inhibition Restores Neuronal Cell Death in Oxygen-Glucose Deprivation Model of Ischemia.

    Science.gov (United States)

    Madineni, Anusha; Alhadidi, Qasim; Shah, Zahoor A

    2016-03-01

    Ischemia is a condition associated with decreased blood supply to the brain, eventually leading to death of neurons. It is associated with a diverse cascade of responses involving both degenerative and regenerative mechanisms. At the cellular level, the changes are initiated prominently in the neuronal cytoskeleton. Cofilin, a cytoskeletal actin severing protein, is known to be involved in the early stages of apoptotic cell death. Evidence supports its intervention in the progression of disease states like Alzheimer's and ischemic kidney disease. In the present study, we have hypothesized the possible involvement of cofilin in ischemia. Using PC12 cells and mouse primary cultures of cortical neurons, we investigated the potential role of cofilin in ischemia in two different in vitro ischemic models: chemical induced oxidative stress and oxygen-glucose deprivation/reperfusion (OGD/R). The expression profile studies demonstrated a decrease in phosphocofilin levels in all models of ischemia, implying stress-induced cofilin activation. Furthermore, calcineurin and slingshot 1L (SSH) phosphatases were found to be the signaling mediators of the cofilin activation. In primary cultures of cortical neurons, cofilin was found to be significantly activated after 1 h of OGD. To delineate the role of activated cofilin in ischemia, we knocked down cofilin by small interfering RNA (siRNA) technique and tested the impact of cofilin silencing on neuronal viability. Cofilin siRNA-treated neurons showed a significant reduction of cofilin levels in all treatment groups (control, OGD, and OGD/R). Additionally, cofilin siRNA-reduced cofilin mitochondrial translocation and caspase 3 cleavage, with a concomitant increase in neuronal viability. These results strongly support the active role of cofilin in ischemia-induced neuronal degeneration and apoptosis. We believe that targeting this protein mediator has a potential for therapeutic intervention in ischemic brain injury and stroke.

  11. Activation of autophagy in a rat model of retinal ischemia following high intraocular pressure.

    Directory of Open Access Journals (Sweden)

    Antonio Piras

    Full Text Available Acute primary open angle glaucoma is an optic neuropathy characterized by the elevation of intraocular pressure, which causes retinal ischemia and neuronal death. Rat ischemia/reperfusion enhances endocytosis of both horseradish peroxidase (HRP or fluorescent dextran into ganglion cell layer (GCL neurons 24 h after the insult. We investigated the activation of autophagy in GCL-neurons following ischemia/reperfusion, using acid phosphatase (AP histochemistry and immunofluorescence against LC3 and LAMP1. Retinal I/R lead to the appearance of AP-positive granules and LAMP1-positive vesicles 12 and 24 h after the insult, and LC3 labelling at 24 h, and induced a consistent retinal neuron death. At 48 h the retina was negative for autophagic markers. In addition, Western Blot analysis revealed an increase of LC3 levels after damage: the increase in the conjugated, LC3-II isoform is suggestive of autophagic activity. Inhibition of autophagy by 3-methyladenine partially prevented death of neurons and reduces apoptotic markers, 24 h post-lesion. The number of neurons in the GCL decreased significantly following I/R (I/R 12.21±1.13 vs controls 19.23±1.12 cells/500 µm; this decrease was partially prevented by 3-methyladenine (17.08±1.42 cells/500 µm, which potently inhibits maturation of autophagosomes. Treatment also prevented the increase in glial fibrillary acid protein immunoreactivity elicited by I/R. Therefore, targeting autophagy could represent a novel and promising treatment for glaucoma and retinal ischemia.

  12. Brain scan in cerebral ischemia. An experimental model in the rat

    International Nuclear Information System (INIS)

    Turner, J.H.

    1975-01-01

    A rapid embolic method for consistent induction of stroke in the rat is described. Brain scans were performed using a micro-pinhole collimator system, and the value of the model for studies in localization of radiopharmaceuticals in cerebral ischemia is demonstrated

  13. Exploiting partial knowledge for efficient model analysis

    OpenAIRE

    Macedo, Nuno; Cunha, Alcino; Pessoa, Eduardo José Dias

    2017-01-01

    The advancement of constraint solvers and model checkers has enabled the effective analysis of high-level formal specification languages. However, these typically handle a specification in an opaque manner, amalgamating all its constraints in a single monolithic verification task, which often proves to be a performance bottleneck. This paper addresses this issue by proposing a solving strategy that exploits user-provided partial knowledge, namely by assigning symbolic bounds to the problem’s ...

  14. Dual AAV therapy ameliorates exercise-induced muscle injury and functional ischemia in murine models of Duchenne muscular dystrophy.

    Science.gov (United States)

    Zhang, Yadong; Yue, Yongping; Li, Liang; Hakim, Chady H; Zhang, Keqing; Thomas, Gail D; Duan, Dongsheng

    2013-09-15

    Neuronal nitric oxide synthase (nNOS) membrane delocalization contributes to the pathogenesis of Duchenne muscular dystrophy (DMD) by promoting functional muscle ischemia and exacerbating muscle injury during exercise. We have previously shown that supra-physiological expression of nNOS-binding mini-dystrophin restores normal blood flow regulation and prevents functional ischemia in transgenic mdx mice, a DMD model. A critical next issue is whether systemic dual adeno-associated virus (AAV) gene therapy can restore nNOS-binding mini-dystrophin expression and mitigate muscle activity-related functional ischemia and injury. Here, we performed systemic gene transfer in mdx and mdx4cv mice using a pair of dual AAV vectors that expressed a 6 kb nNOS-binding mini-dystrophin gene. Vectors were packaged in tyrosine mutant AAV-9 and co-injected (5 × 10(12) viral genome particles/vector/mouse) via the tail vein to 1-month-old dystrophin-null mice. Four months later, we observed 30-50% mini-dystrophin positive myofibers in limb muscles. Treatment ameliorated histopathology, increased muscle force and protected against eccentric contraction-induced injury. Importantly, dual AAV therapy successfully prevented chronic exercise-induced muscle force drop. Doppler hemodynamic assay further showed that therapy attenuated adrenergic vasoconstriction in contracting muscle. Our results suggest that partial transduction can still ameliorate nNOS delocalization-associated functional deficiency. Further evaluation of nNOS binding mini-dystrophin dual AAV vectors is warranted in dystrophic dogs and eventually in human patients.

  15. Coding with partially hidden Markov models

    DEFF Research Database (Denmark)

    Forchhammer, Søren; Rissanen, J.

    1995-01-01

    Partially hidden Markov models (PHMM) are introduced. They are a variation of the hidden Markov models (HMM) combining the power of explicit conditioning on past observations and the power of using hidden states. (P)HMM may be combined with arithmetic coding for lossless data compression. A general...... 2-part coding scheme for given model order but unknown parameters based on PHMM is presented. A forward-backward reestimation of parameters with a redefined backward variable is given for these models and used for estimating the unknown parameters. Proof of convergence of this reestimation is given....... The PHMM structure and the conditions of the convergence proof allows for application of the PHMM to image coding. Relations between the PHMM and hidden Markov models (HMM) are treated. Results of coding bi-level images with the PHMM coding scheme is given. The results indicate that the PHMM can adapt...

  16. Thymoquinone protects end organs from abdominal aorta ischemia/reperfusion injury in a rat model

    Directory of Open Access Journals (Sweden)

    Mehmet Salih Aydin

    2015-02-01

    Full Text Available Introduction: Previous studies have demonstrated that thymoquinone has protective effects against ischemia reperfusion injury to various organs like lungs, kidneys and liver in different experimental models. Objective: We aimed to determine whether thymoquinone has favorable effects on lung, renal, heart tissues and oxidative stress in abdominal aorta ischemia-reperfusion injury. Methods: Thirty rats were divided into three groups as sham (n=10, control (n=10 and thymoquinone (TQ treatment group (n=10. Control and TQ-treatment groups underwent abdominal aorta ischemia for 45 minutes followed by a 120-min period of reperfusion. In the TQ-treatment group, thymoquinone was given 5 minutes. before reperfusion at a dose of 20 mg/kg via an intraperitoneal route. Total antioxidant capacity, total oxidative status (TOS, and oxidative stress index (OSI in blood serum were measured and lung, kidney, and heart tissue histopathology were evaluated with light microscopy. Results: Total oxidative status and oxidative stress index activity in blood samples were statistically higher in the control group compared to the sham and TQ-treatment groups (P<0.001 for TOS and OSI. Control group injury scores were statistically higher compared to sham and TQ-treatment groups (P<0.001 for all comparisons. Conclusion: Thymoquinone administered intraperitoneally was effective in reducing oxidative stress and histopathologic injury in an acute abdominal aorta ischemia-reperfusion rat model.

  17. TECHNIQUE OF EXTRACORPOREAL PARTIAL NEPHRECTOMY IN TERMS OF PHARMACO-COLD ISCHEMIA WITHOUT CROSSING THE URETER WITH RENAL VESSELS ORTHOTOPIC REPLANTATION IN PATIENTS WITH RENAL CELL CARCINOMA

    Directory of Open Access Journals (Sweden)

    Alexander Gritskevitch

    2015-01-01

    Full Text Available Background. The most difficult is to determine medical tactics in patients with renal cell carcinoma (RCC with intraparenchimal and central localization in the single, the only functioning kidney, as well as with a combination of tumor and other illnesses in contralateral kidney. Partial nephrectomy leading to renal replacement therapy results in life-threatening complications and poor prognosis. The priority is to develop organ-preserving treatment: from minimally invasive endoscopic surgery to ex vivo kidney resection. Aim: to develop a technique of extracorporeal partial nephrectomy in terms of pharmaco-cold ischemia without crossing the ureter with renal vessels orthotopic replantation in patients with RCC. Materials and methods. The study included 37 patients with pT1a-T3vN0M0-1G1-3 RCC with intraparenchymal and central tumor location. The average age of the patients was 55.32 ± 13.1 years. The ratio of men and women - 2.7:1. Bilateral renal tumors were observed in 3 (8.1% patients, and the RCC of the single functioning kidney in 6 (16.2% patients. One patient (2.7% was diagnosed RCC of a single kidney with intraluminal invasion (cava-renal form. Results. The mean operation time was 413.97 ± 89.14 minutes. The mean warm ischemia time – 8.39 ± 4.75 minutes. Cold ischemia lasted from 70 to 240 minutes, on the average 151.41 ± 41.29 min. The amount of blood loss made up 729.03 ± 481.4 ml. Perioperative complications were detected in 3 (8.1% patients. In two cases after starting the renal blood flow the kidney was found to be nonviable and had to be removed. And in one case the recurrent prosthetic thrombosis of the renal artery resulted in a renal scarring. Postoperative complications were observed in 18 (48.6% patients. According to Clavien-Dindo classification there were 8 low grade (I-II degree complications (44.4%, 8 other of III degree, and one IV degree complication, and there was one lethal case (V degree. Conclusion

  18. Parameter Estimation of Partial Differential Equation Models.

    Science.gov (United States)

    Xun, Xiaolei; Cao, Jiguo; Mallick, Bani; Carroll, Raymond J; Maity, Arnab

    2013-01-01

    Partial differential equation (PDE) models are commonly used to model complex dynamic systems in applied sciences such as biology and finance. The forms of these PDE models are usually proposed by experts based on their prior knowledge and understanding of the dynamic system. Parameters in PDE models often have interesting scientific interpretations, but their values are often unknown, and need to be estimated from the measurements of the dynamic system in the present of measurement errors. Most PDEs used in practice have no analytic solutions, and can only be solved with numerical methods. Currently, methods for estimating PDE parameters require repeatedly solving PDEs numerically under thousands of candidate parameter values, and thus the computational load is high. In this article, we propose two methods to estimate parameters in PDE models: a parameter cascading method and a Bayesian approach. In both methods, the underlying dynamic process modeled with the PDE model is represented via basis function expansion. For the parameter cascading method, we develop two nested levels of optimization to estimate the PDE parameters. For the Bayesian method, we develop a joint model for data and the PDE, and develop a novel hierarchical model allowing us to employ Markov chain Monte Carlo (MCMC) techniques to make posterior inference. Simulation studies show that the Bayesian method and parameter cascading method are comparable, and both outperform other available methods in terms of estimation accuracy. The two methods are demonstrated by estimating parameters in a PDE model from LIDAR data.

  19. Injectable skeletal muscle matrix hydrogel promotes neovascularization and muscle cell infiltration in a hindlimb ischemia model

    Directory of Open Access Journals (Sweden)

    JA DeQuach

    2012-06-01

    Full Text Available Peripheral artery disease (PAD currently affects approximately 27 million patients in Europe and North America, and if untreated, may progress to the stage of critical limb ischemia (CLI, which has implications for amputation and potential mortality. Unfortunately, few therapies exist for treating the ischemic skeletal muscle in these conditions. Biomaterials have been used to increase cell transplant survival as well as deliver growth factors to treat limb ischemia; however, existing materials do not mimic the native skeletal muscle microenvironment they are intended to treat. Furthermore, no therapies involving biomaterials alone have been examined. The goal of this study was to develop a clinically relevant injectable hydrogel derived from decellularized skeletal muscle extracellular matrix and examine its potential for treating PAD as a stand-alone therapy by studying the material in a rat hindlimb ischemia model. We tested the mitogenic activity of the scaffold’s degradation products using an in vitro assay and measured increased proliferation rates of smooth muscle cells and skeletal myoblasts compared to collagen. In a rat hindlimb ischemia model, the femoral artery was ligated and resected, followed by injection of 150 µL of skeletal muscle matrix or collagen 1 week post-injury. We demonstrate that the skeletal muscle matrix increased arteriole and capillary density, as well as recruited more desmin-positive and MyoD-positive cells compared to collagen. Our results indicate that this tissue-specific injectable hydrogel may be a potential therapy for treating ischemia related to PAD, as well as have potential beneficial effects on restoring muscle mass that is typically lost in CLI.

  20. Partial differential equation models in macroeconomics.

    Science.gov (United States)

    Achdou, Yves; Buera, Francisco J; Lasry, Jean-Michel; Lions, Pierre-Louis; Moll, Benjamin

    2014-11-13

    The purpose of this article is to get mathematicians interested in studying a number of partial differential equations (PDEs) that naturally arise in macroeconomics. These PDEs come from models designed to study some of the most important questions in economics. At the same time, they are highly interesting for mathematicians because their structure is often quite difficult. We present a number of examples of such PDEs, discuss what is known about their properties, and list some open questions for future research. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  1. [Physiological basis of a possible increase in the efficacy of the photo- and magnetotherapy of the visual nerve upon partial atrophy and ischemia].

    Science.gov (United States)

    Shlygin, V V; Tiuliaev, A P; Ioĭleva, E E; Maksimov, G V

    2004-01-01

    An approach to the choice of the parameters of physiotherapeutic and biophysical influence on the visual nerve was proposed. The approach is based on parallel photo- and magnetostimulation of excitable fibers in which the morphological and electrophysiological properties of fibers and some parameters of the pathological processes associated with partial artophy and ischemia are taken into account. A method for correlating the photostimulation by light flashes (intensity 65 mWt at emission wavelength 660 nm) of a portion of the retina with the choice of the parameters of magnetic influence (amplitude 73 mT, duration of the wave front of 40 ms, and frequency of pulse sequence of about 1 Hz) on the visual nerve was developed.

  2. Detection of viable myocardium in canine model with myocardial ischemia and ischemia-reperfusion by 125I-BMIPP: relation to regional blood flow

    International Nuclear Information System (INIS)

    Huang Gang; Zhao Huiyang; Shen Xuedong; Li Qing; Yuan Jimin; Zhu Cuiying

    1999-01-01

    Objective: The effects of BMIPP (β-methyl-iodophenyl pentadecanoic acid) on detecting viable myocardium and the relation between regional blood flow and the uptake of BMIPP were evaluated in canine model of myocardial ischemia and ischemia-reperfusion. Methods: 12 open-chest dogs under anesthesia were divided into two groups. Group I (ischemia group) had left circumflex coronary arterial occlusion for 2 h and group II (ischemia-reperfusion group) was occluded for 1 h and followed by 2 h reperfusion. Myocardial blood flow was measured with 99 Tc m -microspheres. 30 min after intravenous injection of 125 I-BMIPP and 99 Tc m -microspheres, the heart was excised rapidly and stained with Evans blue and NBT. Tissue samples (divided into approximately 1 g) of left ventricle were obtained, weighed and counted for 125 I and 99 Tc m . Regional blood flow and the uptake of BMIPP were expressed as percentages of average values in non-ischemic myocardium (two to three tissue samples) from the normal myocardium. Results: In ischemic myocardium (NBT positive samples), the uptake of BMIPP was relatively higher compared with regional blood flow [(67 +- 23)% vs (42 +- 19)%, P 0.05]. In ischemia-reperfusion group, regional blood flow was increased in ischemic and necrotic tissues, but the uptake of BMIPP was not enhanced with the increasing blood flow. Conclusions: BMIPP uptake seems to provide metabolic information independent of regional blood flow. The mismatching between regional blood flow and BMIPP uptake may indicate myocardial viability in the regions of hypoperfusion and the uptake of BMIPP in ischemic myocardium was related to existence of cellular metabolism

  3. RC-3095, a Selective Gastrin-Releasing Peptide Receptor Antagonist, Does Not Protect the Lungs in an Experimental Model of Lung Ischemia-Reperfusion Injury

    Directory of Open Access Journals (Sweden)

    Vera L. Oliveira-Freitas

    2015-01-01

    Full Text Available RC-3095, a selective GRPR antagonist, has been shown to have anti-inflammatory properties in different models of inflammation. However, its protective effect on lungs submitted to lung ischemia-reperfusion injury has not been addressed before. Then, we administrated RC-3095 intravenously before and after lung reperfusion using an animal model of lung ischemia-reperfusion injury (LIRI by clamping the pulmonary hilum. Twenty Wistar rats were subjected to an experimental model in four groups: SHAM, ischemia-reperfusion (IR, RC-Pre, and RC-Post. The final mean arterial pressure significantly decreased in IR and RC-Pre compared to their values before reperfusion (P<0.001. The RC-Post group showed significant decrease of partial pressure of arterial oxygen at the end of the observation when compared to baseline (P=0.005. Caspase-9 activity was significantly higher in the RC-Post as compared to the other groups (P<0.013. No significant differences were observed in eNOS activity among the groups. The groups RC-Pre and RC-Post did not show any significant decrease in IL-1β (P=0.159 and TNF-α (P=0.260, as compared to IR. The histological score showed no significant differences among the groups. In conclusion, RC-3095 does not demonstrate a protective effect in our LIRI model. Additionally, its use after reperfusion seems to potentiate cell damage, stimulating apoptosis.

  4. Parameter Estimation of Partial Differential Equation Models

    KAUST Repository

    Xun, Xiaolei

    2013-09-01

    Partial differential equation (PDE) models are commonly used to model complex dynamic systems in applied sciences such as biology and finance. The forms of these PDE models are usually proposed by experts based on their prior knowledge and understanding of the dynamic system. Parameters in PDE models often have interesting scientific interpretations, but their values are often unknown and need to be estimated from the measurements of the dynamic system in the presence of measurement errors. Most PDEs used in practice have no analytic solutions, and can only be solved with numerical methods. Currently, methods for estimating PDE parameters require repeatedly solving PDEs numerically under thousands of candidate parameter values, and thus the computational load is high. In this article, we propose two methods to estimate parameters in PDE models: a parameter cascading method and a Bayesian approach. In both methods, the underlying dynamic process modeled with the PDE model is represented via basis function expansion. For the parameter cascading method, we develop two nested levels of optimization to estimate the PDE parameters. For the Bayesian method, we develop a joint model for data and the PDE and develop a novel hierarchical model allowing us to employ Markov chain Monte Carlo (MCMC) techniques to make posterior inference. Simulation studies show that the Bayesian method and parameter cascading method are comparable, and both outperform other available methods in terms of estimation accuracy. The two methods are demonstrated by estimating parameters in a PDE model from long-range infrared light detection and ranging data. Supplementary materials for this article are available online. © 2013 American Statistical Association.

  5. Dragon's blood dropping pills have protective effects on focal cerebral ischemia rats model.

    Science.gov (United States)

    Xin, Nian; Yang, Fang-Ju; Li, Yan; Li, Yu-Juan; Dai, Rong-Ji; Meng, Wei-Wei; Chen, Yan; Deng, Yu-Lin

    2013-12-15

    Dragon's blood is a bright red resin obtained from Dracaena cochinchinensis (Lour.) S.C.Chen (Yunnan, China). As a traditional Chinese medicinal herb, it has great traditional medicinal value and is used for wound healing and to stop bleeding. Its main biological activity comes from phenolic compounds. In this study, phenolic compounds were made into dropping pills and their protective effects were examined by establishing focal cerebral ischemia rats model used method of Middle Cerebral Artery Occlusion (MCAO), and by investigating indexes of neurological scores, infarct volume, cerebral index, cerebral water content and oxidation stress. Compared to model group, high, middle and low groups of Dragon's blood dropping pills could improve the neurological function significantly (ppills had protective effects on focal cerebral ischemia rats. Copyright © 2013 Elsevier GmbH. All rights reserved.

  6. A model of ischemia-induced neuroblast activation in the adult subventricular zone.

    Directory of Open Access Journals (Sweden)

    Davide Vergni

    Full Text Available We have developed a rat brain organotypic culture model, in which tissue slices contain cortex-subventricular zone-striatum regions, to model neuroblast activity in response to in vitro ischemia. Neuroblast activation has been described in terms of two main parameters, proliferation and migration from the subventricular zone into the injured cortex. We observed distinct phases of neuroblast activation as is known to occur after in vivo ischemia. Thus, immediately after oxygen/glucose deprivation (6-24 hours, neuroblasts reduce their proliferative and migratory activity, whereas, at longer time points after the insult (2 to 5 days, they start to proliferate and migrate into the damaged cortex. Antagonism of ionotropic receptors for extracellular ATP during and after the insult unmasks an early activation of neuroblasts in the subventricular zone, which responded with a rapid and intense migration of neuroblasts into the damaged cortex (within 24 hours. The process is further enhanced by elevating the production of the chemoattractant SDf-1alpha and may also be boosted by blocking the activation of microglia. This organotypic model which we have developed is an excellent in vitro system to study neurogenesis after ischemia and other neurodegenerative diseases. Its application has revealed a SOS response to oxygen/glucose deprivation, which is inhibited by unfavorable conditions due to the ischemic environment. Finally, experimental quantifications have allowed us to elaborate a mathematical model to describe neuroblast activation and to develop a computer simulation which should have promising applications for the screening of drug candidates for novel therapies of ischemia-related pathologies.

  7. Protective Effects of Dihydrocaffeic Acid, a Coffee Component Metabolite, on a Focal Cerebral Ischemia Rat Model

    Directory of Open Access Journals (Sweden)

    Kyungjin Lee

    2015-06-01

    Full Text Available We recently reported the protective effects of chlorogenic acid (CGA in a transient middle cerebral artery occlusion (tMCAo rat model. The current study further investigated the protective effects of the metabolites of CGA and dihydrocaffeic acid (DHCA was selected for further study after screening using the same tMCAo rat model. In the current study, tMCAo rats (2 h of MCAo followed by 22 h of reperfusion were injected with various doses of DHCA at 0 and 2 h after onset of ischemia. We assessed brain damage, functional deficits, brain edema, and blood-brain barrier damage at 24 h after ischemia. For investigating the mechanism, in vitro zymography and western blotting analysis were performed to determine the expression and activation of matrix metalloproteinase (MMP-2 and -9. DHCA (3, 10, and 30 mg/kg, i.p. dose-dependently reduced brain infarct volume, behavioral deficits, brain water content, and Evans Blue (EB leakage. DHCA inhibited expression and activation of MMP-2 and MMP-9. Therefore, DHCA might be one of the important metabolites of CGA and of natural products, including coffee, with protective effects on ischemia-induced neuronal damage and brain edema.

  8. Nanoparticle-mediated delivery of pioglitazone enhances therapeutic neovascularization in a murine model of hindlimb ischemia.

    Science.gov (United States)

    Nagahama, Ryoji; Matoba, Tetsuya; Nakano, Kaku; Kim-Mitsuyama, Shokei; Sunagawa, Kenji; Egashira, Kensuke

    2012-10-01

    Critical limb ischemia is a severe form of peripheral artery disease (PAD) for which neither surgical revascularization nor endovascular therapy nor current medicinal therapy has sufficient therapeutic effects. Peroxisome proliferator activated receptor-γ agonists present angiogenic activity in vitro; however, systemic administration of peroxisome proliferator-activated receptor-γ agonists is hampered by its side effects, including heart failure. Here, we demonstrate that the nanoparticle (NP)-mediated delivery of the peroxisome proliferator activated receptor-γ agonist pioglitazone enhances its therapeutic efficacy on ischemia-induced neovascularization in a murine model. In a nondiabetic murine model of hindlimb ischemia, a single intramuscular injection of pioglitazone-incorporated NP (1 µg/kg) into ischemic muscles significantly improved the blood flow recovery in the ischemic limbs, significantly increasing the number of CD31-positive capillaries and α-smooth muscle actin-positive arterioles. The therapeutic effects of pioglitazone-incorporated NP were diminished by the peroxisome proliferator activated receptor-γ antagonist GW9662 and were not observed in endothelial NO synthase-deficient mice. Pioglitazone-incorporated NP induced endothelial NO synthase phosphorylation, as demonstrated by Western blot analysis, as well as expression of multiple angiogenic growth factors in vivo, including vascular endothelial growth factor-A, vascular endothelial growth factor-B, and fibroblast growth factor-1, as demonstrated by real-time polymerase chain reaction. Intramuscular injection of pioglitazone (1 µg/kg) was ineffective, and oral administration necessitated a >500 μg/kg per day dose to produce therapeutic effects equivalent to those of pioglitazone-incorporated NP. NP-mediated drug delivery is a novel modality that may enhance the effectiveness of therapeutic neovascularization, surpassing the effectiveness of current treatments for peripheral artery

  9. Role of inflammatory cells and adenosine in lung ischemia reoxygenation injury using a model of lung donation after cardiac death.

    Science.gov (United States)

    Smail, Hassiba; Baste, Jean-Marc; Gay, Arnaud; Begueret, Hugues; Noël, Romain; Morin, Jean-Paul; Litzler, Pierre-Yves

    2016-04-01

    The objective of this study is to analyze the role of inflammation in the lung ischemia reperfusion (IR) injury and determine the protective role of adenosine in an in vitro lung transplantation model. We used a hybrid model of lung donor after cardiac death, with warm ischemia in corpo of varying duration (2 h, 4 h) followed by in vitro lung slices culture for reoxygenation (1 h, 4 h and 24 h), in the presence or not of lymphocytes and of adenosine. To quantify the inflammatory lesions, we performed TNFα, IL2 assays, and histological analysis. In this model of a nonblood perfused system, the addition of lymphocytes during reoxygenation lead to higher rates of TNFα and IL2 after 4 h than after 2 h of warm ischemia (P < .05). These levels increased with the duration of reoxygenation and were maximum at 24 h (P < .05). In the presence of adenosine TNFα and IL2 decreased. After 2 h of warm ischemia, we observed a significant inflammatory infiltration, alveolar thickening and a necrosis of the bronchiolar cells. After 4 h of warm ischemia, alveolar cells necrosis was associated. This model showed that lymphocytes increased the inflammatory response and the histological lesions after 4 h of warm ischemia and that adenosine could have an anti-inflammatory role with potential reconditioning action when used in the pneumoplegia solution.

  10. Sulforaphane exerts neuroprotective effects via suppression of the inflammatory response in a rat model of focal cerebral ischemia

    OpenAIRE

    Ma, Li-Li; Xing, Guo-Ping; Yu, Yin; Liang, Hui; Yu, Tian-Xia; Zheng, Wei-Hong; Lai, Tian-Bao

    2015-01-01

    Inflammatory damage plays an important role in cerebral ischemic pathogenesis and may represent a promising target for treatment. Sulforaphane exerts protective effects in a rat model of focal cerebral ischemia/reperfusion injury by alleviating brain edema. However, the possible mechanisms of sulforaphane after cerebral ischemia/reperfusion injury have not been fully elucidated. Therefore, in the present study, we investigated the effect of sulforaphane on inflammatory reaction and the potent...

  11. Partial Orders and Fully Abstract Models for Concurrency

    DEFF Research Database (Denmark)

    Engberg, Uffe Henrik

    1990-01-01

    In this thesis sets of labelled partial orders are employed as fundamental mathematical entities for modelling nondeterministic and concurrent processes thereby obtaining so-called noninterleaving semantics. Based on different closures of sets of labelled partial orders, simple algebraic language...

  12. The effect of ozone and naringin on intestinal ischemia/reperfusion injury in an experimental model.

    Science.gov (United States)

    Isik, Arda; Peker, Kemal; Gursul, Cebrail; Sayar, Ilyas; Firat, Deniz; Yilmaz, Ismayil; Demiryilmaz, Ismail

    2015-09-01

    The aim of the study was to evaulate the effect of ozone and naringin on the intestine after intestinal ischemia-reperfusion(II/R) injury. Thirty five rats divided into 5 groups of 7 animals: control, II/R, ozone, naringin and naringin + ozone. Only laparotomy and exploration of the superior mesenteric artery (SMA) were done in control group. In the experimental groups, SAM was occluded for 1 h and reperfused for 1 h. 15 min after ischemia, ozone (25 μg/ml, 0.5 mg/kg), naringin (80 mg/kg) and naringin + ozone(80 mg/kg + 25 μg/ml, 0.5 mg/kg) were infused intraperitoneally to each groups. Ileum tissues were harvested to determine intestinal mucosal injury and oxidative stress markers. For SMA occlusion, different than literature, silk suture binding was used. Oxidative stress markers were significantly low in experimental groups compared with II/R group (p < 0.05). Histopathologically, the injury score was significantly low at experimental groups compared with II/R group (p < 0.05). The lowest injury score was encountered at naringine + ozone group. Ozone alone or combined with naringin has a protective effect for mesenteric ischemia. Instead of using instruments such as clamps in the II/R rat model, silk binding may be used safely. Copyright © 2015 IJS Publishing Group Limited. Published by Elsevier Ltd. All rights reserved.

  13. Omega-3 Fatty Acids: Possible Neuroprotective Mechanisms in the Model of Global Ischemia in Rats

    Directory of Open Access Journals (Sweden)

    Maria Elizabeth Pereira Nobre

    2016-01-01

    Full Text Available Background. Omega-3 (ω3 administration was shown to protect against hypoxic-ischemic injury. The objectives were to study the neuroprotective effects of ω3, in a model of global ischemia. Methods. Male Wistar rats were subjected to carotid occlusion (30 min, followed by reperfusion. The groups were SO, untreated ischemic and ischemic treated rats with ω3 (5 and 10 mg/kg, 7 days. The SO and untreated ischemic animals were orally treated with 1% cremophor and, 1 h after the last administration, they were behaviorally tested and euthanized for neurochemical (DA, DOPAC, and NE determinations, histological (Fluoro jade staining, and immunohistochemical (TNF-alpha, COX-2 and iNOS evaluations. The data were analyzed by ANOVA and Newman-Keuls as the post hoc test. Results. Ischemia increased the locomotor activity and rearing behavior that were partly reversed by ω3. Ischemia decreased striatal DA and DOPAC contents and increased NE contents, effects reversed by ω3. This drug protected hippocampal neuron degeneration, as observed by Fluoro-Jade staining, and the increased immunostainings for TNF-alpha, COX-2, and iNOS were partly or totally blocked by ω3. Conclusion. This study showed a neuroprotective effect of ω3, in great part due to its anti-inflammatory properties, stimulating translational studies focusing on its use in clinic for stroke managing.

  14. Thymoquinone protects end organs from abdominal aorta ischemia/reperfusion injury in a rat model.

    Science.gov (United States)

    Aydin, Mehmet Salih; Kocarslan, Aydemir; Kocarslan, Sezen; Kucuk, Ahmet; Eser, İrfan; Sezen, Hatice; Buyukfirat, Evren; Hazar, Abdussemet

    2015-01-01

    Previous studies have demonstrated that thymoquinone has protective effects against ischemia reperfusion injury to various organs like lungs, kidneys and liver in different experimental models. We aimed to determine whether thymoquinone has favorable effects on lung, renal, heart tissues and oxidative stress in abdominal aorta ischemia-reperfusion injury. Thirty rats were divided into three groups as sham (n=10), control (n=10) and thymoquinone (TQ) treatment group (n=10). Control and TQ-treatment groups underwent abdominal aorta ischemia for 45 minutes followed by a 120-min period of reperfusion. In the TQ-treatment group, thymoquinone was given 5 minutes. before reperfusion at a dose of 20 mg/kg via an intraperitoneal route. Total antioxidant capacity, total oxidative status (TOS), and oxidative stress index (OSI) in blood serum were measured and lung, kidney, and heart tissue histopathology were evaluated with light microscopy. Total oxidative status and oxidative stress index activity in blood samples were statistically higher in the control group compared to the sham and TQ-treatment groups (POSI). Control group injury scores were statistically higher compared to sham and TQ-treatment groups (Pmodel.

  15. Sulforaphane exerts neuroprotective effects via suppression of the inflammatory response in a rat model of focal cerebral ischemia.

    Science.gov (United States)

    Ma, Li-Li; Xing, Guo-Ping; Yu, Yin; Liang, Hui; Yu, Tian-Xia; Zheng, Wei-Hong; Lai, Tian-Bao

    2015-01-01

    Inflammatory damage plays an important role in cerebral ischemic pathogenesis and may represent a promising target for treatment. Sulforaphane exerts protective effects in a rat model of focal cerebral ischemia/reperfusion injury by alleviating brain edema. However, the possible mechanisms of sulforaphane after cerebral ischemia/reperfusion injury have not been fully elucidated. Therefore, in the present study, we investigated the effect of sulforaphane on inflammatory reaction and the potential molecular mechanisms in cerebral ischemia rats. We found that sulforaphane significantly attenuated the blood-brain barrier (BBB) disruption; decreased the levels of pro-inflammatory cytokines tumor necrosis factor (TNF)-α and interleukin (IL)-1β; reduced the nitric oxide (NO) levels and inducible nitric oxide synthase (iNOS) activity; inhibited the expression of iNOS and cyclooxygenase-2 (COX-2). In addition, sulforaphane inhibits the expression of p-NF-κB p65 after focal cerebral ischemia-reperfusion injury. Taken together, our results suggest that sulforaphane suppresses the inflammatory response via inhibiting the NF-κB signaling pathway in a rat model of focal cerebral ischemia, and sulforaphane may be a potential therapeutic agent for the treatment of cerebral ischemia injury.

  16. Mathematical Modelling of Intraretinal Oxygen Partial Pressure

    African Journals Online (AJOL)

    Erah

    oxygen availability) is required for retinal oxidative metabolism. .... retina was described using Hill's equation and Fick's law. ... ganglion cell / nerve fiber layer and the superficial ..... parameter values producing the best. Figure 2: Partial ...

  17. Rat model hindlimb ischemia induced via embolization with polyvinyl alcohol and N butyl cyanoacrylate

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Cheong Il; Kim, Hyo Cheol; Song, Yong Sub; Cho, Hye Rim; Lee, Kyoung Bun; Jae, Hwan June; Chung, Jin Wook [Seoul National University Hospital, Seoul (Korea, Republic of)

    2013-12-15

    To investigate the feasibility of a rat model on hindlimb ischemia induced by embolization from the administration of polyvinyl alcohol (PVA) particles or N-butyl cyanoacrylate (NBCA). Unilateral hindlimb ischemia was induced by embolization with NBCA (n = 4), PVA (n = 4) or surgical excision (n = 4) in a total of 12 Sprague-Dawley rats. On days 0, 7 and 14, the time-of-flight magnetic resonance angiography (TOF-MRA) and enhanced MRI were obtained as scheduled by using a 3T-MR scanner. The clinical ischemic index, volume change and degree of muscle necrosis observed on the enhanced MRI in the ischemic hindlimb were being compared among three groups using the analysis of variance. Vascular patency on TOF-MRA was evaluated and correlated with angiographic findings when using an inter-rater agreement test. There was a technical success rate of 100% for both the embolization and surgery groups. The clinical ischemic index did not significantly differ. On day 7, the ratios of the muscular infarctions were 0.436, 0.173 and 0 at thigh levels and 0.503, 0.337 and 0 at calf levels for the NBCA, PVA and surgery groups, respectively. In addition, the embolization group presented increased volume and then decreased volume on days 7 and 14, respectively. The surgery group presented a gradual volume decrease. Good correlation was shown between the TOF-MRA and angiographic findings (kappa value of 0.795). The examined hindlimb ischemia model using embolization with NBCA and PVA particles in rats is a feasible model for further research, and muscle necrosis was evident as compared with the surgical model.

  18. Unilateral Renal Ischemia-Reperfusion as a Robust Model for Acute to Chronic Kidney Injury in Mice.

    Directory of Open Access Journals (Sweden)

    Nathalie Le Clef

    Full Text Available Acute kidney injury (AKI is an underestimated, yet important risk factor for development of chronic kidney disease (CKD. Even after initial total recovery of renal function, some patients develop progressive and persistent deterioration of renal function and these patients are more likely to progress to end-stage renal disease (ESRD. Animal models are indispensable for unravelling the mechanisms underlying this progression towards CKD and ESRD and for the development of new therapeutic strategies in its prevention or treatment. Ischemia (i.e. hypoperfusion after surgery, bleeding, dehydration, shock, or sepsis is a major aetiology in human AKI, yet unilateral ischemia-reperfusion is a rarely used animal model for research on CKD and fibrosis. Here, we demonstrate in C57Bl/6J mice, by both histology and gene expression, that unilateral ischemia-reperfusion without contralateral nephrectomy is a very robust model to study the progression from acute renal injury to long-term tubulo-interstitial fibrosis, i.e. the histopathological hallmark of CKD. Furthermore, we report that the extent of renal fibrosis, in terms of Col I, TGFβ, CCN2 and CCN3 expression and collagen I immunostaining, increases with increasing body temperature during ischemia and ischemia-time. Thus, varying these two main determinants of ischemic injury allows tuning the extent of the long-term fibrotic outcome in this model. Finally, in order to cover the whole practical finesse of ischemia-reperfusion and allow model and data transfer, we provide a referenced overview on crucial technical issues (incl. anaesthesia, analgesia, and pre- and post-operative care with the specific aim of putting starters in the right direction of implementing ischemia in their research and stimulate them, as well as the community, to have a critical view on ischemic literature data.

  19. Cellular infiltrates and injury evaluation in a rat model of warm pulmonary ischemia-reperfusion

    NARCIS (Netherlands)

    Van Putte, BP; Kesecioglu, J; Hendriks, JMH; Persy, VP; van Marck, E; Van Schil, PEY; De Broe, ME

    Introduction Beside lung transplantation, cardiopulmonary bypass, isolated lung perfusion and sleeve resection result in serious pulmonary ischemia - reperfusion injury, clinically known as acute respiratory distress syndrome. Very little is known about cells infiltrating the lung during ischemia -

  20. Omega-3 Fatty Acids: Possible Neuroprotective Mechanisms in the Model of Global Ischemia in Rats

    OpenAIRE

    Nobre, Maria Elizabeth Pereira; Correia, Alyne Oliveira; Mendon?a, Francisco Nilson Maciel; Uchoa, Luiz Ricardo Ara?jo; Vasconcelos, Jessica Tamara Nunes; de Ara?jo, Carlos Ney Alencar; Brito, Gerly Anne de Castro; Siqueira, Rafaelly Maria Pinheiro; Cerqueira, Gilberto dos Santos; Neves, Kelly Rose Tavares; Arida, Ricardo M?rio; Viana, Glauce Socorro de Barros

    2016-01-01

    Background. Omega-3 (ω3) administration was shown to protect against hypoxic-ischemic injury. The objectives were to study the neuroprotective effects of ω3, in a model of global ischemia. Methods. Male Wistar rats were subjected to carotid occlusion (30 min), followed by reperfusion. The groups were SO, untreated ischemic and ischemic treated rats with ω3 (5 and 10 mg/kg, 7 days). The SO and untreated ischemic animals were orally treated with 1% cremophor and, 1 h after the last administrati...

  1. MR perfusion/diffusion-weighted imaging of acute ischemia in an animal model with PET correlation

    International Nuclear Information System (INIS)

    Pickens, D.R.; Dawson, R.C.; Votaw, J.R.; Lorenz, C.H.; Holburn, G.E.; Price, R.R.

    1990-01-01

    This paper evaluates acute cerebral ischemia in an animal model with MR perfusion/diffusion-sensitive pulse sequences and to compare the results with PET regional cerebral blood flow (rCBF) measurements. An embolizing agent was injected into the proximal middle cerebral artery (MCA) of a dog, and this was followed by DSA. Next, the animal was imaged in a 1.5-T MR system with perfusion/diffusion-sensitive spin-echo pulse sequence. Then, PET imaging was performed with H 2 O 15 at corresponding levels of the brain

  2. A Generalized Partial Credit Model: Application of an EM Algorithm.

    Science.gov (United States)

    Muraki, Eiji

    1992-01-01

    The partial credit model with a varying slope parameter is developed and called the generalized partial credit model (GPCM). Analysis results for simulated data by this and other polytomous item-response models demonstrate that the rating formulation of the GPCM is adaptable to the analysis of polytomous item responses. (SLD)

  3. Accelerated oxygen-induced retinopathy is a reliable model of ischemia-induced retinal neovascularization.

    Science.gov (United States)

    Villacampa, Pilar; Menger, Katja E; Abelleira, Laura; Ribeiro, Joana; Duran, Yanai; Smith, Alexander J; Ali, Robin R; Luhmann, Ulrich F; Bainbridge, James W B

    2017-01-01

    Retinal ischemia and pathological angiogenesis cause severe impairment of sight. Oxygen-induced retinopathy (OIR) in young mice is widely used as a model to investigate the underlying pathological mechanisms and develop therapeutic interventions. We compared directly the conventional OIR model (exposure to 75% O2 from postnatal day (P) 7 to P12) with an alternative, accelerated version (85% O2 from P8 to P11). We found that accelerated OIR induces similar pre-retinal neovascularization but greater retinal vascular regression that recovers more rapidly. The extent of retinal gliosis is similar but neuroretinal function, as measured by electroretinography, is better maintained in the accelerated model. We found no systemic or maternal morbidity in either model. Accelerated OIR offers a safe, reliable and more rapid alternative model in which pre-retinal neovascularization is similar but retinal vascular regression is greater.

  4. [Identification of early irreversible damage area in a rat model of cerebral ischemia and reperfusion].

    Science.gov (United States)

    Liu, S; Guo, Y

    2000-02-01

    To observe the early neuron ischemic damage in focal cerebral ischemia/reperfusion with histostaining methods of argyrophil III (AG III), Toludine blue(TB), and H&E, and to make out the 'separating line' between the areas of reversible and irreversible early ischemic damage. Forty-two male Wistar rats were randomly divided into the following groups: pseudo-surgical, blank-control, O2R0(occluded for 2 hours and reperfused for 0 hour), O2R0.5, O2R2, O2R4, O2R24. There were 6 rats in each group. Rats in experimental groups were suffered focal cerebral ischemia/reperfusion through a nylon suture method. After a special processor for tissue manage, the brain were coronal sectioned and stained with H&E, TB, and AG III. The area where dark neurons dwell in (ischemic core) were calculated with image analysis system. The success rate of ischemic model for this experiment is 90%. After being stained with argyrophil III method, normal neurons appear yellow or pale brown, which is hardly distinguished from the pale brown background. The ischemic neuron stained black, and has collapsed body and "corkscrew-like" axon or dentries, which were broken to some extent. The neuropil in the dark neurons dwelt area appears gray or pale black, which is apparently different from the pale brown neighborhood area. The distribution of dark neurons in cortex varies according to different layers, and has a character of columnar form. The dark neurons present as early as 2 hours ischemia without reperfusion with AG III method. AG III stain could selectively display early ischemic neurons, the area dwelt by dark neurons represent early ischemic core. Dark neuron is possibly the irreversibly damaged neuron. Identification of dark neurons could be helpful in the discrimination between early ischemic center and penumbra.

  5. Autofluorescence dynamics during reperfusion following long-term renal ischemia in a rat model

    Energy Technology Data Exchange (ETDEWEB)

    Raman, R N; Pivetti, C D; Matthews, D L; Troppmann, C; Demos, S G

    2008-02-08

    Optical properties of near-surface kidney tissue were monitored in order to assess response during reperfusion to long (20 minutes) versus prolonged (150 minutes) ischemia in an in vivo rat model. Specifically, autofluorescence images of the exposed surfaces of both the normal and the ischemic kidneys were acquired during both injury and reperfusion alternately under 355 nm and 266 nm excitations. The temporal profile of the emission of the injured kidney during the reperfusion phase under 355 nm excitation was normalized to that under 266 nm as a means to account for changes in tissue optical properties independent of ischemia as well as changes in the illumination/collection geometrical parameters in future clinical implementation of this technique using a hand-held probe. The scattered excitation light signal was also evaluated as a reference signal and found to be inadequate. Characteristic time constants were extracted using fit to a relaxation model and found to have larger mean values following 150 minutes of injury. The mean values were then compared with the outcome of a chronic survival study where the control kidney had been removed. Rat kidneys exhibiting longer time constants were much more likely to fail. This may lead to a method to assess kidney viability and predict its ability to recover in the initial period following transplantation or resuscitation.

  6. Evaluation of hypoxic tissue dynamics with 18F-FMISO PET in a rat model of permanent cerebral ischemia.

    Science.gov (United States)

    Rojas, Santiago; Herance, José Raul; Abad, Sergio; Jiménez, Xavier; Pareto, Deborah; Ruiz, Alba; Torrent, Èlia; Figueiras, Francisca P; Popota, Foteini; Fernández-Soriano, Francisco J; Planas, Anna M; Gispert, Juan D

    2011-06-01

    [¹⁸F]Fluoromisonidazole (¹⁸F-FMISO) is a nitroimidazole derivative that has been proposed as a positron emission tomography (PET) radiotracer to detect hypoxic tissue in vivo. This compound accumulates in hypoxic but viable tissue and may be a good candidate for evaluating the ischemic penumbra. We evaluated the time course of ¹⁸F-FMISO uptake using PET in a rat model of permanent cerebral ischemia and the correlation with histological changes. Rats (n = 14) were subjected to permanent ischemia by intraluminal occlusion of the middle cerebral artery in order to assess by PET the uptake of ¹⁸F-FMISO at various times over 24 h following ischemia. The PET results were compared to histological changes with Nissl and 2,3,5 triphenyltetrazolium chloride staining. Elevated uptake of ¹⁸F-FMISO was detected in the infarcted area up to 8 h after occlusion but was no longer detected at 24 h, a time point coincident with pan necrosis of the tissue. Our findings suggest that salvageable tissue persists for up to 8 h in this rat model of brain ischemia. We propose ¹⁸F-FMISO PET as a tool for evaluating the ischemic penumbra after cerebral ischemia.

  7. Acute retinal ischemia caused by controlled low ocular perfusion pressure in a porcine model. Electrophysiological and histological characterisation

    DEFF Research Database (Denmark)

    Kyhn, Maria Voss; Warfvinge, Karin; Scherfig, Erik

    2009-01-01

    The purpose of this study was to establish, and characterize a porcine model of acute, controlled retinal ischemia. The controlled retinal ischemia was produced by clamping the ocular perfusion pressure (OPP) in the left eye to 5 mm Hg for 2 h. The OPP was defined as mean arterial blood pressure...... of the amplitudes obtained in the experimental, left eye, and the control, right eye. Quantitative histology was performed to measure the survival of ganglion cells, amacrine cells and horizontal cells 2-6 weeks after the ischemic insult. An OPP of 5 mm Hg for 2h induced significant reductions in the amplitudes...... the ischemic insult. This model seems to be suitable for investigations of therapeutic initiatives in diseases involving acute retinal ischemia....

  8. Effects of the Rabdosia rubescens total flavonoids on focal cerebral ischemia reperfusion model in rats

    Directory of Open Access Journals (Sweden)

    Mingsan Miao

    2017-05-01

    Full Text Available The effect of the Rabdosia rubescens total flavonoids on focal cerebral ischemia reperfusion model in rats was observed. The model group, nimodipine group, cerebral collateral group, and large, medium and small dose group of the Rabdosia rubescens total flavonoids were administered with corresponding drugs but sham operation group and model group were administered the same volume of 0.5%CMC, 1 times a day, continuous administration of 7 d. After 1 h at 7 d to medicine, left incision in the middle of the neck of rats after anesthesia, we can firstly expose and isolate the left common carotid artery (CCA, and then expose external carotid artery (ECA and internal carotid artery (ICA. The common carotid artery and the external carotid artery are ligated. Then internal carotid artery with arterial clamp is temporarily clipped. Besides, cut the incision of 0.2 mm from 5 cm of the bifurcation of the common carotid artery. A thread Line bolt is inserted with more than 18–20 mm from bifurcation of CCA into the internal carotid artery until there is resistance. Then the entrance of the middle cerebral artery is blocked and internal carotid artery is ligated (the blank group only exposed the left blood vessel without Plugging wire. Finally it is gently pulled out the plug line after 2 h. Results: Compared with the model mice, Rabdosia rubescens total flavonoids can significantly relieve the injury of brain in hippocampus and cortex nerve cells; experimental rat focal cerebral ischemia was to improve again perfusion model of nerve function defect score mortality; significantly reduce brain homogenate NOS activity and no content, MDA, IL-1, TNF-a, ICAM-1 content; increase in brain homogenate SOD and ATPase activity (P < 0.05, P < 0.01; and reduce the serum S-100β protein content. Each dose group of the Rabdosia rubescens total flavonoids has a better Improvement effect on focal cerebral ischemia reperfusion model in rats.

  9. Sildenafil citrate protects skeletal muscle of ischemia-reperfusion injury: immunohistochemical study in rat model

    Directory of Open Access Journals (Sweden)

    Dinani Matoso Fialho de Oliveira Armstrong

    2013-04-01

    Full Text Available PURPOSE: To investigate the effect of sildenafil citrate (SC on skeletal muscle ischemia-reperfusion (IR injury in rats. METHODS: Adult male Wistar rats were randomized into three groups: vehicle-treated control (CTG, sildenafil citrate-treated (SCG, and sham group (SG. CTG and SCG had femoral artery occluded for 6 hours. Saline or 1 mg/kg of SC was given 5.5 hours after occlusion. SG had a similar procedure without artery occlusion. Soleus muscle samples were acquired 4 or 24h after the reperfusion. Immunohistochemistry caspase-3 analysis was used to estimate apoptosis using the apoptotic ratio (computed as positive/negative cells. Wilcoxon rank-sum or Kruskal-Wallis tests were used to assess differences among groups. RESULTS: Eighteen animals were included in the 4h reperfusion groups and 21 animals in the 24h reperfusion groups. The mean apoptotic ratio was 0.18±0.1 for the total cohort; 0.14±0.06 for the 4h reperfusion groups and 0.19±0.08 for the 24h groups (p<0.05. The SCG had lower caspase-3 ratio compared to the control groups at the 24h reperfusion time point (p<0.05. CONCLUSION: Sildenafil citrate administration after the onset of the ischemic injury reduces IR-induced cellular damage in skeletal muscle in this rat hindlimb ischemia model.

  10. Effects of CDP-choline on neurologic deficits and cerebral glucose metabolism in a rat model of cerebral ischemia

    Energy Technology Data Exchange (ETDEWEB)

    Kakihana, M.; Fukuda, N.; Suno, M.; Nagaoka, A.

    1988-02-01

    The effects of cytidine 5'-diphosphocholine (CDP-choline) on neurologic deficits and cerebral glucose metabolism were studied in a rat model of transient cerebral ischemia. Cerebral ischemia was induced by occluding both common carotid arteries for 20 or 30 minutes 24 hours after the vertebral arteries were permanently occluded by electrocautery. CDP-choline was administered intraperitoneally twice daily for 4 days after reestablishing carotid blood flow. CDP-choline at two dosages (50 and 250 mg/kg) shortened the time required for recovery of spontaneous motor activity in a dose-related manner; recovery time was measured early after reperfusion. Neurologic signs were observed for 10 days. High-dose CDP-choline improved neurologic signs in the rats within 20-30 minutes of ischemia. When cerebral glucose metabolism was assessed on Day 4, increases in the levels of glucose and pyruvate were accompanied by decreases in the synthesis of labeled acetylcholine from uniformly labeled (/sup 14/C)glucose measured in the cerebral cortex of rats with 30 minutes of ischemia. High-dose CDP-choline also attenuated changes in these variables. CDP-(1,2-/sup 14/C)choline injected intravenously 10 minutes after reperfusion was used for membrane lipid biosynthesis. These results indicate that CDP-choline has beneficial effects on brain dysfunction induced by cerebral ischemia, which may be due in part to the restorative effects of CDP-choline on disturbed cerebral glucose metabolism, probably by stimulating phospholipid biosynthesis.

  11. Effects of CDP-choline on neurologic deficits and cerebral glucose metabolism in a rat model of cerebral ischemia

    International Nuclear Information System (INIS)

    Kakihana, M.; Fukuda, N.; Suno, M.; Nagaoka, A.

    1988-01-01

    The effects of cytidine 5'-diphosphocholine (CDP-choline) on neurologic deficits and cerebral glucose metabolism were studied in a rat model of transient cerebral ischemia. Cerebral ischemia was induced by occluding both common carotid arteries for 20 or 30 minutes 24 hours after the vertebral arteries were permanently occluded by electrocautery. CDP-choline was administered intraperitoneally twice daily for 4 days after reestablishing carotid blood flow. CDP-choline at two dosages (50 and 250 mg/kg) shortened the time required for recovery of spontaneous motor activity in a dose-related manner; recovery time was measured early after reperfusion. Neurologic signs were observed for 10 days. High-dose CDP-choline improved neurologic signs in the rats within 20-30 minutes of ischemia. When cerebral glucose metabolism was assessed on Day 4, increases in the levels of glucose and pyruvate were accompanied by decreases in the synthesis of labeled acetylcholine from uniformly labeled [ 14 C]glucose measured in the cerebral cortex of rats with 30 minutes of ischemia. High-dose CDP-choline also attenuated changes in these variables. CDP-[1,2- 14 C]choline injected intravenously 10 minutes after reperfusion was used for membrane lipid biosynthesis. These results indicate that CDP-choline has beneficial effects on brain dysfunction induced by cerebral ischemia, which may be due in part to the restorative effects of CDP-choline on disturbed cerebral glucose metabolism, probably by stimulating phospholipid biosynthesis

  12. pO2 and regional blood flow in a rabbit model of limb ischemia.

    Science.gov (United States)

    Grinberg, Oleg Y; Hou, Huagang; Grinberg, Stalina A; Moodie, Karen L; Demidenko, Eugene; Friedman, Bruce J; Post, Mark J; Swartz, Harold M

    2004-06-01

    Oxygen tension (pO2) in muscles and regional blood flow were measured in a rabbit model of limb ischemia. pO2 was measured repetitively by EPR oximetry with EMS char in four different muscle groups in the same animals. Blood flow in the same muscles at several time points was measured using microspheres. A linear mixed effects model was developed to analyze the data on pO2 and blood flow. The results suggest that while under normal conditions pO2 in muscles does not depend significantly on blood flow, immediately after arterial occlusion pO2 correlates linearly with blood flow. Within two weeks of occlusion the pO2 is recovered to 45% of baseline. This study demonstrates, for the first time, the applicability of EPR oximetry in animals larger than rodents.

  13. Teaching Modeling with Partial Differential Equations: Several Successful Approaches

    Science.gov (United States)

    Myers, Joseph; Trubatch, David; Winkel, Brian

    2008-01-01

    We discuss the introduction and teaching of partial differential equations (heat and wave equations) via modeling physical phenomena, using a new approach that encompasses constructing difference equations and implementing these in a spreadsheet, numerically solving the partial differential equations using the numerical differential equation…

  14. Influence of acidosis and hypoxia on liver ischemia and reperfusion injury in an in vivo rat model

    NARCIS (Netherlands)

    Heijnen, Bob H. M.; Elkhaloufi, Yasser; Straatsburg, Irene H.; van Gulik, Thomas M.

    2002-01-01

    The contribution of acidosis to the development of reperfusion injury is controversial. In this study, we examined the effects of respiratory acidosis and hypoxia in a frequently used in vivo liver ischemia and reperfusion (I/R) injury rat model. Rats were anesthetized with intraperitoneal

  15. EFFECTS OF EARLY ANGIOTENSIN-CONVERTING ENZYME-INHIBITION IN A PIG MODEL OF MYOCARDIAL-ISCHEMIA AND REPERFUSION

    NARCIS (Netherlands)

    VANWIJNGAARDEN, J; TOBE, TJM; WEERSINK, EGL; BEL, KJ; DEGRAEFF, PA; DELANGEN, CDJ; VANGILST, WH; WESSELING, H

    In a blind, randomized study, the effects of perindopril, a nonsulfhydryl-containing angiotensin-converting enzyme (ACE) inhibitor, were compared with those of placebo in a closed-chest pig model of myocardial infraction. In anesthetized pigs, my ocardinal ischemia and reperfusion were induced by

  16. Positron emission tomography imaging of angiogenesis in a murine hindlimb ischemia model with 64Cu-labeled TRC105.

    Science.gov (United States)

    Orbay, Hakan; Zhang, Yin; Hong, Hao; Hacker, Timothy A; Valdovinos, Hector F; Zagzebski, James A; Theuer, Charles P; Barnhart, Todd E; Cai, Weibo

    2013-07-01

    The goal of this study was to assess ischemia-induced angiogenesis with (64)Cu-NOTA-TRC105 positron emission tomography (PET) in a murine hindlimb ischemia model of peripheral artery disease (PAD). CD105 binding affinity/specificity of NOTA-conjugated TRC105 (an anti-CD105 antibody) was evaluated by flow cytometry, which exhibited no difference from unconjugated TRC105. BALB/c mice were anesthetized, and the right femoral artery was ligated to induce hindlimb ischemia, with the left hindlimb serving as an internal control. Laser Doppler imaging showed that perfusion in the ischemic hindlimb plummeted to ∼ 20% of the normal level after surgery and gradually recovered to near normal level on day 24. Ischemia-induced angiogenesis was noninvasively monitored and quantified with (64)Cu-NOTA-TRC105 PET on postoperative days 1, 3, 10, 17, and 24. (64)Cu-NOTA-TRC105 uptake in the ischemic hindlimb increased significantly from the control level of 1.6 ± 0.2 %ID/g to 14.1 ± 1.9 %ID/g at day 3 (n = 3) and gradually decreased with time (3.4 ± 1.9 %ID/g at day 24), which correlated well with biodistribution studies performed on days 3 and 24. Blocking studies confirmed the CD105 specificity of tracer uptake in the ischemic hindlimb. Increased CD105 expression on days 3 and 10 following ischemia was confirmed by histology and reverse transcription polymerase chain reaction (RT-PCR). This is the first report of PET imaging of CD105 expression during ischemia-induced angiogenesis. (64)Cu-NOTA-TRC105 PET may play multiple roles in future PAD-related research and improve PAD patient management by identifying the optimal timing of treatment and monitoring the efficacy of therapy.

  17. Neuroprotective intervention after hypoxia-ischemia may change intracerebral metabolic measures in a newborn piglet model

    DEFF Research Database (Denmark)

    Andelius, Ted Carl; Bøgh, Nikolaj; Pedersen, Mette Vestergaard

    Introduction Hypoxic-Ischemic Neonatal Encephalopathy (HIE) is a major contributor to neurological impairment and death in children. Due to the similarity with the human brain, newborn piglets are often used in studies of new treatments for HIE. Cell death after hypoxia ischemia (HI) occurs...... measured intracranial pressure (ICP), flow, temperature, and oxygen tension. By microdialysis we measured lactate, glucose, glycerol, and pyruvate. A NIRS-probe was placed on the right side of the head and aEEG electrodes were placed on each side. After 24 hours of stabilisation, HI was induced for 45....... Lactate/pyruvate ratio and ICP showed a parabolic pattern in the HI piglet. Conclusion We present a novel take on an already well-established animal model for HIE. We expect to provide basic knowledge of how interventions may affect intracerebral metabolic measures, pressure and gas...

  18. Partial differential equation models in the socio-economic sciences

    KAUST Repository

    Burger, Martin; Caffarelli, Luis; Markowich, Peter A.

    2014-01-01

    Mathematical models based on partial differential equations (PDEs) have become an integral part of quantitative analysis in most branches of science and engineering, recently expanding also towards biomedicine and socio-economic sciences

  19. Standards and pitfalls of focal ischemia models in spontaneously hypertensive rats: With a systematic review of recent articles

    Directory of Open Access Journals (Sweden)

    Yao Hiroshi

    2012-07-01

    Full Text Available Abstract We reviewed the early development of various focal ischemia models in spontaneously hypertensive rats (SHR, and summarized recent reports on this topic. Among 6 focal ischemia models established in divergent substrains of SHR, distal middle cerebral artery occlusion is the most frequently used and relevant method of focal ischemia in the light of penumbra concept. We performed an online PubMed search (2001–2010, and identified 118 original articles with focal ischemia in SHR. Physiological parameters such as age, body weight, and even blood pressure were often neglected in the literature: the information regarding the physiological parameters of SHR is critical, and should be provided within the methodology section of all articles related to stroke models in SHR. Although the quality of recent studies on neuroprotective strategy is improving, the mechanisms underlying the protection should be more clearly recognized so as to facilitate the translation from animal studies to human stroke. To overcome the genetic heterogeneity in substrains of SHR, new approaches, such as a huge repository of genetic markers in rat strains and the congenic strategy, are currently in progress.

  20. Experimental chronic kidney disease attenuates ischemia-reperfusion injury in an ex vivo rat lung model.

    Directory of Open Access Journals (Sweden)

    Chung-Kan Peng

    Full Text Available Lung ischemia reperfusion injury (LIRI is one of important complications following lung transplant and cardiopulmonary bypass. Although patients on hemodialysis are still excluded as lung transplant donors because of the possible effects of renal failure on the lungs, increased organ demand has led us to evaluate the influence of chronic kidney disease (CKD on LIRI. A CKD model was induced by feeding Sprague-Dawley rats an adenine-rich (0.75% diet for 2, 4 and 6 weeks, and an isolated rat lung in situ model was used to evaluate ischemia reperfusion (IR-induced acute lung injury. The clinicopathological parameters of LIRI, including pulmonary edema, lipid peroxidation, histopathological changes, immunohistochemistry changes, chemokine CXCL1, inducible nitric oxide synthase (iNOS, proinflammatory and anti-inflammatory cytokines, heat shock protein expression, and nuclear factor-κB (NF-κB activation were determined. Our results indicated that adenine-fed rats developed CKD as characterized by increased blood urea nitrogen and creatinine levels and the deposition of crystals in the renal tubules and interstitium. IR induced a significant increase in the pulmonary arterial pressure, lung edema, lung injury scores, the expression of CXCL1 mRNA, iNOS level, and protein concentration of the bronchial alveolar lavage fluid (BALF. The tumor necrosis factor-α levels in the BALF and perfusate; the interleukin-10 level in the perfusate; and the malondialdehyde levels in the lung tissue and perfusate were also significantly increased by LIRI. Counterintuitively, adenine-induced CKD significantly attenuated the severity of lung injury induced by IR. CKD rats exhibited increased heat shock protein 70 expression and decreased activation of NF-κB signaling. In conclusion, adenine-induced CKD attenuated LIRI by inhibiting the NF-κB pathway.

  1. Mathematical Modelling of Intraretinal Oxygen Partial Pressure

    African Journals Online (AJOL)

    Erah

    The system of non-linear differential equations was solved numerically using Runge-kutta. Nystroms method. ... artery occlusion. Keywords: Mathematical modeling, Intraretinal oxygen pressure, Retinal capillaries, Oxygen ..... Mass transfer,.

  2. Neuroprotective effect of p-coumaric acid in rat model of embolic cerebral ischemia

    Directory of Open Access Journals (Sweden)

    Mustafa Guven

    2015-04-01

    Conclusion:Our results showed that p-coumaric acid is a neuroprotective agent on account of its strong anti-oxidant and anti-apoptotic features. Moreover, p-coumaric acid decreased the focal ischemia. Extra effort should be made to introduce p-coumaric acid as a promising therapeutic agent to be utilized for treatment of human cerebral ischemia in the future.

  3. Placental Growth Factor Reduces Blood Pressure in a Uteroplacental Ischemia Model of Preeclampsia in Nonhuman Primates.

    Science.gov (United States)

    Makris, Angela; Yeung, Kristen R; Lim, Shirlene M; Sunderland, Neroli; Heffernan, Scott; Thompson, John F; Iliopoulos, Jim; Killingsworth, Murray C; Yong, Jim; Xu, Bei; Ogle, Robert F; Thadhani, Ravi; Karumanchi, S Ananth; Hennessy, Annemarie

    2016-06-01

    An imbalance in the angiogenesis axis during pregnancy manifests as clinical preeclampsia because of endothelial dysfunction. Circulating soluble fms-like tyrosine kinase 1 (sFLT-1) increases and placental growth factor (PlGF) reduces before and during disease. We investigated the clinical and biochemical effects of replenishing the reduced circulating PlGF with recombinant human PlGF (rhPlGF) and thus restoring the angiogenic balance. Hypertensive proteinuria was induced in a nonhuman primate (Papio hamadryas) by uterine artery ligation at 136 days gestation (of a 182-day pregnancy). Two weeks after uteroplacental ischemia, rhPlGF (rhPlGF, n=3) or normal saline (control, n=4) was administered by subcutaneous injection (100 μg/kg per day) for 5 days. Blood pressure was monitored by intra-arterial radiotelemetry and sFLT-1 and PlGF by ELISA. Uteroplacental ischemia resulted in experimental preeclampsia evidenced by increased blood pressure, proteinuria, and endotheliosis on renal biopsy and elevated sFLT-1. PlGF significantly reduced after uteroplacental ischemia. rhPlGF reduced systolic blood pressure in the treated group (-5.2±0.8 mm Hg; from 132.6±6.6 mm Hg to 124.1±7.6 mm Hg) compared with an increase in systolic blood pressure in controls (6.5±3 mm Hg; from 131.3±1.5 mm Hg to 138.6±1.5 mm Hg). Proteinuria reduced in the treated group (-72.7±55.7 mg/mmol) but increased in the control group. Circulating levels of total sFLT-1 were not affected by the administration of PlGF; however, a reduction in placental sFLT-1 mRNA expression was demonstrated. There was no significant difference between the weights or lengths of the neonates in the rhPlGF or control group; however, this study was not designed to assess fetal safety or outcomes. Increasing circulating PlGF by the administration of rhPlGF improves clinical parameters in a primate animal model of experimental preeclampsia. © 2016 American Heart Association, Inc.

  4. Melatonin attenuates lung injury in a hind limb ischemia–reperfusion rat model

    Directory of Open Access Journals (Sweden)

    Hamed Takhtfooladi

    2015-01-01

    Full Text Available Objective: This study evaluated the protective antioxidant effect of melatonin on lung injury as a remote organ after skeletal muscle ischemia–reperfusion in rats. Methods: Thirty male Wistar rats were allocated randomly into three experimental groups: operated with no ischemia (Sham group, ischemia–reperfusion group and ischemia–reperfusion + melatonin group. Hind limb ischemia was induced by clamping the femoral artery. After 2 h ischemia, the clamp was removed and the animal underwent 24 h reperfusion. Rats in the ischemia–reperfusion + melatonin group received melatonin (10 mg/kg i.v., immediately before the clamp was removed. At the end of the trial, animals were euthanized and the lungs were removed for water content determination, histopathological and biochemical studies. Results: In the ischemia–reperfusion + melatonin group, tissues showed less intense histological abnormalities such as neutrophilic infiltration, intra-alveolar hemorrhage and edema compared with the ischemia–reperfusion group. Histopathologically, there was a significant difference (P < 0.05 between the two groups. The lung water content in the ischemia–reperfusion + melatonin group was significantly lower than the ischemia–reperfusion group (P < 0.05. Lung tissue myeloperoxidase (MPO activity and nitric oxide (NO level were significantly (P < 0.05 increased by ischemia–reperfusion. The increase in these parameters was reduced by melatonin.Comparing the ischemia–reperfusion + melatonin group with the sham group, no significant increase in all analyzed aspects of the research was observed. Conclusions: These findings suggest that melatonin has preventive effects in lung tissue injury after transient femoral artery occlusion. Keywords: Melatonin, Ischemia–reperfusion, Lung remote injury, Histopathology, Myeloperoxidase, Nitric oxide

  5. Partially natural Two Higgs Doublet Models

    Energy Technology Data Exchange (ETDEWEB)

    Draper, Patrick [Department of Physics, University of California,Broida Hall, Santa Barbara, CA 93106 (United States); Haber, Howard E. [Santa Cruz Institute for Particle Physics, University of California,1156 High Street, Santa Cruz, CA 95064 (United States); Kavli Institute for Theoretical Physics, University of California,Kohn Hall, Santa Barbara, CA 93106 (United States); Ruderman, Joshua T. [Center for Cosmology and Particle Physics, Department of Physics, New York University,4 Washington Pl. New York, NY 10003 (United States)

    2016-06-21

    It is possible that the electroweak scale is low due to the fine-tuning of microscopic parameters, which can result from selection effects. The experimental discovery of new light fundamental scalars other than the Standard Model Higgs boson would seem to disfavor this possibility, since generically such states imply parametrically worse fine-tuning with no compelling connection to selection effects. We discuss counterexamples where the Higgs boson is light because of fine-tuning, and a second scalar doublet is light because a discrete symmetry relates its mass to the mass of the Standard Model Higgs boson. Our examples require new vectorlike fermions at the electroweak scale, and the models possess a rich electroweak vacuum structure. The mechanism that we discuss does not protect a small CP-odd Higgs mass in split or high-scale supersymmetry-breaking scenarios of the MSSM due to an incompatibility between the discrete symmetries and holomorphy.

  6. Mesenteric Ischemia

    Directory of Open Access Journals (Sweden)

    Shannon Toohey

    2016-07-01

    Full Text Available Audience: This simulation session is appropriate for emergency medicine residents at any level or medical students. Introduction: Mesenteric ischemia is a rare, but serious cause of abdominal pain. Practitioners must recognize the diagnosis quickly. The clinical course rapidly advances from bowel ischemia to infarction, sepsis, and frequently death. Mesenteric ischemia accounts for approximately 1% of all ED cases of abdominal pain in the elderly, but the mortality is as high as 93%. Objectives: At the end of this simulation session, the learner will: 1 Recognize signs and symptoms of mesenteric ischemia; 2 order appropriately imaging and labs in the workup of an elderly patient with abdominal pain; 3 manage a patient with mesenteric ischemia, a rare, but serious cause of abdominal pain in the elderly; 4 discuss anchoring bias, specifically related to patients referred to the ED with an established diagnosis by outside specialists. Methods: This educational session is a high-fidelity simulation.

  7. Allogeneic amniotic membrane-derived mesenchymal stromal cell transplantation in a porcine model of chronic myocardial ischemia

    Directory of Open Access Journals (Sweden)

    Kimura M

    2012-01-01

    Full Text Available Introduction. Amniotic membrane contains a multipotential stem cell population and is expected to possess the machinery to regulate immunological reactions. We investigated the safety and efficacy of allogeneic amniotic membrane-derived mesenchymal stromal cell (AMSC transplantation in a porcine model of chronic myocardial ischemia as a preclinical trial. Methods. Porcine AMSCs were isolated from amniotic membranes obtained by cesarean section just before delivery and were cultured to increase their numbers before transplantation. Chronic myocardial ischemia was induced by implantation of an ameroid constrictor around the left circumflex coronary artery. Four weeks after ischemia induction, nine swine were assigned to undergo either allogeneic AMSC transplantation or normal saline injection. Functional analysis was performed by echocardiography, and histological examinations were carried out by immunohistochemistry 4 weeks after AMSC transplantation. Results. Echocardiography demonstrated that left ventricular ejection fraction was significantly improved and left ventricular dilatation was well attenuated 4 weeks after AMSC transplantation. Histological assessment showed a significant reduction in percentage of fibrosis in the AMSC transplantation group. Injected allogeneic green fluorescent protein (GFP-expressing AMSCs were identified in the immunocompetent host heart without the use of any immunosuppressants 4 weeks after transplantation. Immunohistochemistry revealed that GFP colocalized with cardiac troponin T and cardiac troponin I. Conclusions. We have demonstrated that allogeneic AMSC transplantation produced histological and functional improvement in the impaired myocardium in a porcine model of chronic myocardial ischemia. The transplanted allogeneic AMSCs survived without the use of any immunosuppressants and gained cardiac phenotype through either their transdifferentiation or cell fusion.

  8. Extracellular Matrix Hydrogel Promotes Tissue Remodeling, Arteriogenesis, and Perfusion in a Rat Hindlimb Ischemia Model

    Directory of Open Access Journals (Sweden)

    Jessica L. Ungerleider, BS

    2016-01-01

    Full Text Available Although surgical and endovascular revascularization can be performed in peripheral arterial disease (PAD, 40% of patients with critical limb ischemia do not have a revascularization option. This study examines the efficacy and mechanisms of action of acellular extracellular matrix-based hydrogels as a potential novel therapy for treating PAD. We tested the efficacy of using a tissue-specific injectable hydrogel derived from decellularized porcine skeletal muscle (SKM and compared this to a new human umbilical cord-derived matrix (hUC hydrogel, which could have greater potential for tissue regeneration because of the younger age of the tissue source. In a rodent hindlimb ischemia model, both hydrogels were injected 1-week post-surgery and perfusion was regularly monitored with laser speckle contrast analysis to 35 days post-injection. There were significant improvements in hindlimb tissue perfusion and perfusion kinetics with both biomaterials. Histologic analysis indicated that the injected hydrogels were biocompatible, and resulted in arteriogenesis, rather than angiogenesis, as well as improved recruitment of skeletal muscle progenitors. Skeletal muscle fiber morphology analysis indicated that the muscle treated with the tissue-specific SKM hydrogel more closely matched healthy tissue morphology. Whole transcriptome analysis indicated that the SKM hydrogel caused a shift in the inflammatory response, decreased cell death, and increased blood vessel and muscle development. These results show the efficacy of an injectable ECM hydrogel alone as a potential therapy for treating patients with PAD. Our results indicate that the SKM hydrogel improved functional outcomes through stimulation of arteriogenesis and muscle progenitor cell recruitment.

  9. Evaluation of adenosine preconditioning with 99mTc-His10-annexin V in a porcine model of myocardium ischemia and reperfusion injury: preliminary study

    International Nuclear Information System (INIS)

    Ye Fei; Fang Wei; Wang Feng; Hua Zichun; Wang Zizheng; Yang Xiang

    2011-01-01

    Purpose: The goal of this study was to evaluate the feasibility of 99m Tc-His 10 -annexin V for the detection of acute myocardial cell death and to assess the effect of adenosine preconditioning in a porcine model of myocardium ischemia and reperfusion injury (RI). Materials and Methods: 99m Tc-His 10 -annexin V was prepared by one-step direct labeling, and RCP and radiostability were tested. The binding of 99m Tc-His 10 -annexin V to apoptosis was validated in vitro using camptothecin-induced Jurkat cells. In vivo biodistribution was determined in mice by the dissection method. Ischemia of 20-30 min was induced by balloon occlusion of the epicardial coronary artery of the porcine model (n=14). Adenosine was infused intravenously in six pigs before coronary occlusion. 99m Tc-His 10 -annexin V (n=12) was injected intravenously at 1 h after reperfusion. SPECT/CT was acquired at 3 h postinjection. Myocardial perfusion imaging (MPI) with 99m Tc-MIBI was also performed 1 day after His 10 -annexin V imaging. Cardiac tissues were analyzed postmortem using hematoxylin-and-eosin and TUNEL staining. Caspase-3 activity was measured to confirm the presence of apoptosis. Results: 99m Tc-His 10 -annexin V had a RCP >98% and high stability 2 h after radiolabeling; it could bind to apoptotic cells with high affinity. Biodistribution of 99m Tc-His 10 -annexin V showed a predominant uptake in the kidney and relatively low uptake in the myocardium, liver and gastrointestinal tract; rapid clearance from blood and kidney was observed. In the untreated group, intense uptake of His 10 -annexin V was visualized in the defect which was shown in MPI, whereas in the adenosine group a mild uptake of 99m Tc-His 10 -annexin was found in the risk area which showed no defects in the 99m Tc-MIBI image. TUNEL staining and activated caspase-3 confirmed the ongoing apoptosis in RI. Adenosine preconditioning significantly diminished the level of apoptosis. Uptake of His 10 -annexin V in RI correlated

  10. Variance Function Partially Linear Single-Index Models1.

    Science.gov (United States)

    Lian, Heng; Liang, Hua; Carroll, Raymond J

    2015-01-01

    We consider heteroscedastic regression models where the mean function is a partially linear single index model and the variance function depends upon a generalized partially linear single index model. We do not insist that the variance function depend only upon the mean function, as happens in the classical generalized partially linear single index model. We develop efficient and practical estimation methods for the variance function and for the mean function. Asymptotic theory for the parametric and nonparametric parts of the model is developed. Simulations illustrate the results. An empirical example involving ozone levels is used to further illustrate the results, and is shown to be a case where the variance function does not depend upon the mean function.

  11. Curcumin and dexmedetomidine prevents oxidative stress and renal injury in hind limb ischemia/reperfusion injury in a rat model.

    Science.gov (United States)

    Karahan, M A; Yalcin, S; Aydogan, H; Büyükfirat, E; Kücük, A; Kocarslan, S; Yüce, H H; Taskın, A; Aksoy, N

    2016-06-01

    Curcumin and dexmedetomidine have been shown to have protective effects in ischemia-reperfusion injury on various organs. However, their protective effects on kidney tissue against ischemia-reperfusion injury remain unclear. We aimed to determine whether curcumin or dexmedetomidine prevents renal tissue from injury that was induced by hind limb ischemia-reperfusion in rats. Fifty rats were divided into five groups: sham, control, curcumin (CUR) group (200 mg/kg curcumin, n = 10), dexmedetomidine (DEX) group (25 μg/kg dexmedetomidine, n = 10), and curcumin-dexmedetomidine (CUR-DEX) group (200 mg/kg curcumin and 25 μg/kg dexmedetomidine). Curcumin and dexmedetomidine were administered intraperitoneally immediately after the end of 4 h ischemia, just 5 min before reperfusion. The extremity re-perfused for 2 h and then blood samples were taken and total antioxidant capacity (TAC), total oxidative status (TOS) levels, and oxidative stress index (OSI) were measured, and renal tissue samples were histopathologically examined. The TAC activity levels in blood samples were significantly lower in the control than the other groups (p OSI were found to be significantly increased in the control group compared to others groups (p model.

  12. Protective effect of active perfusion in porcine models of acute myocardial ischemia

    Science.gov (United States)

    Feng, Zanxiang; Mao, Zhifu; Dong, Shengjun; Liu, Baohui

    2016-01-01

    Mortality rates associated with off-pump coronary artery bypass (CAB) are relatively high, as the majority of patients requiring CAB are at a high risk for cardiac events. The present study aimed to establish porcine models of acute myocardial ischemia, and evaluate the protective role of shunt and active perfusion. A total of 30 pigs were randomly assigned to five groups, as follows: i) Sham (control); ii) A1 (shunt; stenosis rate, 55%); iii) A2 (shunt; stenosis rate, 75%); iv) B1 (active perfusion; stenosis rate, 55%); and v) B2 (active perfusion; stenosis rate, 75%) groups. Aortic pressure (P0), left anterior descending coronary pressure (P1), and coronary effective perfusion pressure (P1/P0) were measured. The expression levels of tumor necrosis factor-α (TNF-α), cardiac troponin (cTnI), creatine kinase-myocardial band (CK-MB), interleukin (IL)-6, IL-10, B-cell lymphoma 2 (Bcl-2), and caspase-3 were detected using enzyme-linked immunosorbent assay or western blotting. The myocardial apoptosis rate was determined using the terminal deoxynucleotidyl transferase dUTP nick end labeling assay. Ischemia models with stenosis rates of 55 and 75% were successfully constructed following suturing of the descending artery. Compared with the control, the 55 and 75% stenosis groups demonstrated significantly decreased P1/P0, increased expression levels of TNF-α, cTnI, CK-MB, IL-6, IL-10 and caspase-3, an increased rate of myocardial apoptosis, and a decreased expression level of anti-apoptotic protein, Bcl-2. At 30 min following successful establishment of the model (ST segment elevation to 1 mm), group B demonstrated significantly increased P1/P0, decreased expression levels of TNF-α, cTnI, CK-MB, IL-6, IL-10 and caspase-3, a decreased rate of myocardial apoptosis, and an increased expression level of anti-apoptotic protein, Bcl-2. Furthermore, the current study indicated that active perfusion was more efficacious in maintaining myocardial perfusion and alleviating

  13. Study and optimization of the partial discharges in capacitor model ...

    African Journals Online (AJOL)

    Page 1 ... experiments methodology for the study of such processes, in view of their modeling and optimization. The obtained result is a mathematical model capable to identify the parameters and the interactions between .... 5mn; the next landing is situated in 200 V over the voltage of partial discharges appearance and.

  14. Latent Partially Ordered Classification Models and Normal Mixtures

    Science.gov (United States)

    Tatsuoka, Curtis; Varadi, Ferenc; Jaeger, Judith

    2013-01-01

    Latent partially ordered sets (posets) can be employed in modeling cognitive functioning, such as in the analysis of neuropsychological (NP) and educational test data. Posets are cognitively diagnostic in the sense that classification states in these models are associated with detailed profiles of cognitive functioning. These profiles allow for…

  15. Fitting and Testing Conditional Multinormal Partial Credit Models

    Science.gov (United States)

    Hessen, David J.

    2012-01-01

    A multinormal partial credit model for factor analysis of polytomously scored items with ordered response categories is derived using an extension of the Dutch Identity (Holland in "Psychometrika" 55:5-18, 1990). In the model, latent variables are assumed to have a multivariate normal distribution conditional on unweighted sums of item…

  16. Understanding Rasch Measurement: Partial Credit Model and Pivot Anchoring.

    Science.gov (United States)

    Bode, Rita K.

    2001-01-01

    Describes the Rasch measurement partial credit model, what it is, how it differs from other Rasch models, and when and how to use it. Also describes the calibration of instruments with increasingly complex items. Explains pivot anchoring and illustrates its use and describes the effect of pivot anchoring on step calibrations, item hierarchy, and…

  17. Partial-Order Reduction for GPU Model Checking

    NARCIS (Netherlands)

    Neele, T.; Wijs, A.; Bosnacki, D.; van de Pol, Jan Cornelis; Artho, C; Legay, A.; Peled, D.

    2016-01-01

    Model checking using GPUs has seen increased popularity over the last years. Because GPUs have a limited amount of memory, only small to medium-sized systems can be verified. For on-the-fly explicit-state model checking, we improve memory efficiency by applying partial-order reduction. We propose

  18. Neuroprotective effect of curcumin on spinal cord in rabbit model with ischemia/reperfusion.

    Science.gov (United States)

    Liu, Zhi-Qiang; Xing, Shan-Shan; Zhang, Wei

    2013-03-01

    Ischemic/reperfusion (I/R) injury of the spinal cord is a serious complication that can result from thoracoabdominal aortic surgery. To investigate the neuroprotective effect of curcumin against I/R injury in a rabbit model. A total of 36 rabbits were randomly divided into three groups: sham, I/R, and curcumin-treated group. Rabbits were subject to 30-min aortic occlusion to induce transient spinal cord ischemia. Neurological function was observed after reperfusion and spinal cord segment (L3-L5) was collected for histopathological evaluation. Malondialdehyde (MDA) and total superoxide dismutase (SOD) activity were also assayed. Rabbits in I/R group were induced to paraplegia. While after 48-hour treatment, compared with I/R group, curcumin significantly improved neurological function, reduced cell apoptosis and MDA levels as well as increased SOD activity (P curcumin, at least in an animal model, can attenuate transient spinal cord ischemic injury potentially via reducing oxidative damage, which may provide a novel approach in the treatment of spinal cord ischemic injury.

  19. Cerebrospinal Fluid Metabolomics After Natural Product Treatment in an Experimental Model of Cerebral Ischemia.

    Science.gov (United States)

    Huan, Tao; Xian, Jia Wen; Leung, Wing Nang; Li, Liang; Chan, Chun Wai

    2016-11-01

    Cerebrospinal fluid (CSF) is an important biofluid for diagnosis of and research on neurological diseases. However, in-depth metabolomic profiling of CSF remains an analytical challenge due to the small volume of samples, particularly in small animal models. In this work, we report the application of a high-performance chemical isotope labeling (CIL) liquid chromatography-mass spectrometry (LC-MS) workflow for CSF metabolomics in Gastrodia elata and Uncaria rhynchophylla water extract (GUW)-treated experimental cerebral ischemia model of rat. The GUW is a commonly used Traditional Chinese Medicine (TCM) for hypertension and brain disease. This study investigated the amine- and phenol-containing biomarkers in the CSF metabolome. After GUW treatment for 7 days, the neurological deficit score was significantly improved with infarct volume reduction, while the integrity of brain histological structure was preserved. Over 1957 metabolites were quantified in CSF by dansylation LC-MS. The analysis of this comprehensive list of metabolites suggests that metabolites associated with oxidative stress, inflammatory response, and excitotoxicity change during GUW-induced alleviation of ischemic injury. This work is significant in that (1) it shows CIL LC-MS can be used for in-depth profiling of the CSF metabolome in experimental ischemic stroke and (2) identifies several potential molecular targets (that might mediate the central nervous system) and associate with pharmacodynamic effects of some frequently used TCMs.

  20. Use of hypoxia imaging agent 99mTc-HL91 in rat cerebral ischemia models

    International Nuclear Information System (INIS)

    Zhou Ying; Qu Wanying; Li Meng; Chen Fang; Yao Zhiming; Zhu Ming; Zhu Lin

    1999-01-01

    Objective: To explore the possibility of diagnosis for cerebrovascular disease by a novel synthetic hypoxia agent 99m Tc-HL91 used in rat cerebral ischemia models. Methods: Pharmacological experiments of 99m Tc-HL91 were carried out including common properties, radiochemical purity, stability in vitro, anomalous toxicity test and biodistribution in mice. Fifteen cerebral ischemic rat models were established and received 99m Tc-HL91 scintigraphy. Results: 1) HL91 kits were labelled with 99m Tc easily and showed high radiochemical purity and stability. 2) Rapid clearance in blood, heart and lungs and high activity in liver, kidneys and intestines were observed. Relatively low uptake in brain was identified. 3) The radioactivity in ischemic brain tissue increased significantly at 4h postinjection in both rat images and isolated brain images. 4) The radioactivity ratios of lesion to normal brain tissue by drawing ROIs in isolated brain planar images were 0.98 +- 0.06, 0.99 +- 0.05, 1.29 +- 0.03, 1.56 +- 0.14 and 1.66 +- 0.06 at 1,2,4,8 and 12 h postinjection, respectively. There were significant differences among all groups except for 1 h and 2 h, 8 h and 12 h postinjection (P 99m Tc-HL91 in the hypoxic, ischemic brain tissue have been proved. It is appropriate to perform imaging at 4 h postinjection

  1. Effect of global cardiac ischemia on human ventricular fibrillation: insights from a multi-scale mechanistic model of the human heart.

    Directory of Open Access Journals (Sweden)

    Ivan V Kazbanov

    2014-11-01

    Full Text Available Acute regional ischemia in the heart can lead to cardiac arrhythmias such as ventricular fibrillation (VF, which in turn compromise cardiac output and result in secondary global cardiac ischemia. The secondary ischemia may influence the underlying arrhythmia mechanism. A recent clinical study documents the effect of global cardiac ischaemia on the mechanisms of VF. During 150 seconds of global ischemia the dominant frequency of activation decreased, while after reperfusion it increased rapidly. At the same time the complexity of epicardial excitation, measured as the number of epicardical phase singularity points, remained approximately constant during ischemia. Here we perform numerical studies based on these clinical data and propose explanations for the observed dynamics of the period and complexity of activation patterns. In particular, we study the effects on ischemia in pseudo-1D and 2D cardiac tissue models as well as in an anatomically accurate model of human heart ventricles. We demonstrate that the fall of dominant frequency in VF during secondary ischemia can be explained by an increase in extracellular potassium, while the increase during reperfusion is consistent with washout of potassium and continued activation of the ATP-dependent potassium channels. We also suggest that memory effects are responsible for the observed complexity dynamics. In addition, we present unpublished clinical results of individual patient recordings and propose a way of estimating extracellular potassium and activation of ATP-dependent potassium channels from these measurements.

  2. Niosomes of Ascorbic Acid and α-Tocopherol in the Cerebral Ischemia-Reperfusion Model in Male Rats

    OpenAIRE

    Varshosaz, Jaleh; Taymouri, Somayeh; Pardakhty, Abbas; Asadi-Shekaari, Majid; Babaee, Abodolreza

    2014-01-01

    The objective of the present study was to prepare a stable iv injectable formulation of ascorbic acid and α-tocopherol in preventing the cerebral ischemia. Different niosomal formulations were prepared by Span and Tween mixed with cholesterol. The physicochemical characteristics of niosomal formulations were evaluated in vitro. For in vivo evaluation, the rats were made ischemic by middle cerebral artery occlusion model for 30 min and the selected formulation was used for determining its neur...

  3. DIGE proteome analysis reveals suitability of ischemic cardiac in vitro model for studying cellular response to acute ischemia and regeneration.

    Directory of Open Access Journals (Sweden)

    Sina Haas

    Full Text Available Proteomic analysis of myocardial tissue from patient population is suited to yield insights into cellular and molecular mechanisms taking place in cardiovascular diseases. However, it has been limited by small sized biopsies and complicated by high variances between patients. Therefore, there is a high demand for suitable model systems with the capability to simulate ischemic and cardiotoxic effects in vitro, under defined conditions. In this context, we established an in vitro ischemia/reperfusion cardiac disease model based on the contractile HL-1 cell line. To identify pathways involved in the cellular alterations induced by ischemia and thereby defining disease-specific biomarkers and potential target structures for new drug candidates we used fluorescence 2D-difference gel electrophoresis. By comparing spot density changes in ischemic and reperfusion samples we detected several protein spots that were differentially abundant. Using MALDI-TOF/TOF-MS and ESI-MS the proteins were identified and subsequently grouped by functionality. Most prominent were changes in apoptosis signalling, cell structure and energy-metabolism. Alterations were confirmed by analysis of human biopsies from patients with ischemic cardiomyopathy.With the establishment of our in vitro disease model for ischemia injury target identification via proteomic research becomes independent from rare human material and will create new possibilities in cardiac research.

  4. DSA-guided embolization in establishing different canine spinal cord ischemia models and relevant diffusion-weighted imaging study

    International Nuclear Information System (INIS)

    Zhang Jingsong; Sun Lijun; Huan Yi; He Hongde; Zhang Xuexin; Zhao Haitao; Zhang Jing; Zhang Xijing

    2006-01-01

    Objective: To evaluate DSA-guided embolization in establishing different spinal cord ischemia models of canine and relevant diffusion-weighted imaging (DWI) application. Methods: Nine canines were randomly divided into three groups with different matching of lipiodol and diatrizoate meglumine which were injected into bilateral intercostal arteries at 9-11 level guided by DSA monitor. Then observe the changes of motor function and pathologic findings, especially perform routine MRI and DWI by a 1.5 T MR system. Results: Except one case, 8 embolization models were established successfully. Among three groups, slight-group got slight injury and muscle power was about 3-5 grade and range of injury was about two vertebra distance; medium-group presented obvious paraplegia and muscle power was 0-1 grade and range of injury was between 3-4 vertebra distance; severe-group showed greater severity and larger range of injury. All lesions presented high signals at routine MRI and DWI. Conclusion: Using different matching of lipiodol and diatrizoate meglumine can establish different spinal cord ischemia models of canine by DSA- guided embolization and DWI can be performed successfully by 1.5 T MR system, which may be a good method for advanced study of spinal cord ischemia. (authors)

  5. Optimized Model of Cerebral Ischemia In situ for the Long-Lasting Assessment of Hippocampal Cell Death

    Directory of Open Access Journals (Sweden)

    Oksana Rybachuk

    2017-07-01

    Full Text Available Among all the brain, the hippocampus is the most susceptible region to ischemic lesion, with the highest vulnerability of CA1 pyramidal neurons to ischemic damage. This damage may cause either prompt neuronal death (within hours or with a delayed appearance (over days, providing a window for applying potential therapies to reduce or prevent ischemic impairments. However, the time course when ischemic damage turns to neuronal death strictly depends on experimental modeling of cerebral ischemia and, up to now, studies were predominantly focused on a short time-window—from hours to up to a few days post-lesion. Using different schemes of oxygen-glucose deprivation (OGD, the conditions taking place upon cerebral ischemia, we optimized a model of mimicking ischemic conditions in organotypical hippocampal slices for the long-lasting assessment of CA1 neuronal death (at least 3 weeks. By combining morphology and electrophysiology, we show that prolonged (30-min duration OGD results in a massive neuronal death and overwhelmed astrogliosis within a week post-OGD whereas OGD of a shorter duration (10-min triggered programmed CA1 neuronal death with a significant delay—within 2 weeks—accompanied with drastically impaired CA1 neuron functions. Our results provide a rationale toward optimized modeling of cerebral ischemia for reliable examination of potential treatments for brain neuroprotection, neuro-regeneration, or testing neuroprotective compounds in situ.

  6. Neuroprotective Effect of Xueshuantong for Injection (Lyophilized in Transient and Permanent Rat Cerebral Ischemia Model

    Directory of Open Access Journals (Sweden)

    Xumei Wang

    2015-01-01

    Full Text Available Xueshuantong for Injection (Lyophilized (XST, a Chinese Materia Medica standardized product extracted from Panax notoginseng (Burk., is used extensively for the treatment of cerebrovascular diseases such as acutely cerebral infarction clinically in China. In the present study, we evaluated the acute and extended protective effects of XST in different rat cerebral ischemic model and explored its effect on peroxiredoxin (Prx 6-toll-like receptor (TLR 4 signaling pathway. We found that XST treatment for 3 days could significantly inhibit transient middle cerebral artery occlusion (MCAO induced infarct volume and swelling percent and regulate the mRNA expression of interleukin-1β (IL-1β, IL-17, IL-23p19, tumor necrosis factor-α (TNFα, and inducible nitric oxide synthase (iNOS in brain. Further study demonstrated that treatment with XST suppressed the protein expression of peroxiredoxin (Prx 6-toll-like receptor (TLR 4 and phosphorylation level of p38 and upregulated the phosphorylation level of STAT3. In permanent MCAO rats, XST could reduce the infarct volume and swelling percent. Moreover, our results revealed that XST treatment could increase the rats’ weight and improve a batch of functional outcomes. In conclusion, the present data suggested that XST could protect against ischemia injury in transient and permanent MCAO rats, which might be related to Prx6-TLR4 pathway.

  7. Bumetanide augments the neuroprotective efficacy of phenobarbital plus hypothermia in a neonatal hypoxia-ischemia model

    Science.gov (United States)

    Liu, YiQing; Shangguan, Yu; Barks, John D.E.; Silverstein, Faye S.

    2014-01-01

    The NaKCl cotransporter NKCC1 facilitates intraneuronal chloride accumulation in the developing brain. Bumetanide, a clinically available diuretic, inhibits this chloride transporter, and augments the antiepileptic effects of phenobarbital in neonatal rodents. In a neonatal cerebral hypoxia-ischemia (HI) model, elicited by right carotid ligation, followed by 90 min 8% O2 exposure in 7-day-old(P7) rats, phenobarbital(PB) increases the neuroprotective efficacy of hypothermia. We evaluated whether bumetanide influenced the neuroprotective efficacy of combination treatment with PB and hypothermia(HT). P7 rats underwent HI lesioning; 15 min later, all received PB (30 mg/kg). 10 min later, half received bumetanide (10 mg/kg, PB-HT+BUM) and half received saline (PB-HT+SAL). One hour after HI, all were cooled (30°C, 3h). Contralateral forepaw sensorimotor function and brain damage were evaluated 1 to 4 weeks later. Forepaw functional measures were close to normal in the PB-HT+BUM group, while deficits persisted in PB-HT+SAL controls; there were corresponding reductions in right cerebral hemisphere damage (at P35, % damage: PB-HT+BUM, 21±16 versus 38±20 in controls). These results provide evidence that NKCC1 inhibition amplifies phenobarbital bioactivity in the immature brain, and suggest that co-administration of phenobarbital and bumetanide may represent a clinically feasible therapy to augment the neuroprotective efficacy of therapeutic hypothermia in asphyxiated neonates. PMID:22398701

  8. Centrifuge modeling of LNAPL transport in partially saturated sand

    NARCIS (Netherlands)

    Esposito, G.; Allersma, H.G.B.; Selvadurai, A.P.S.

    1999-01-01

    Model tests were performed at the Geotechnical Centrifuge Facility of Delft University of Technology, The Netherlands, to examine the mechanics of light nonaqueous phase liquid (LNAPL) movement in a partially saturated porous granular medium. The experiment simulated a 2D spill of LNAPL in an

  9. Detecting Math Anxiety with a Mixture Partial Credit Model

    Science.gov (United States)

    Ölmez, Ibrahim Burak; Cohen, Allan S.

    2017-01-01

    The purpose of this study was to investigate a new methodology for detection of differences in middle grades students' math anxiety. A mixture partial credit model analysis revealed two distinct latent classes based on homogeneities in response patterns within each latent class. Students in Class 1 had less anxiety about apprehension of math…

  10. Cardiac Imaging Using Clinical 1.5 T MRI Scanners in a Murine Ischemia/Reperfusion Model

    Directory of Open Access Journals (Sweden)

    Jakob G. J. Voelkl

    2011-01-01

    Full Text Available To perform cardiac imaging in mice without having to invest in expensive dedicated equipment, we adapted a clinical 1.5 Tesla (T magnetic resonance imaging (MRI scanner for use in a murine ischemia/reperfusion model. Phase-sensitive inversion recovery (PSIR sequence facilitated the determination of infarct sizes in vivo by late gadolinium enhancement. Results were compared to histological infarct areas in mice after ischemia/reperfusion procedure with a good correlation (=0.807, <.001. In addition, fractional area change (FAC was assessed with single slice cine MRI and was matched to infarct size (=−0.837 and fractional shortening (FS measured with echocardiography (=0.860; both <.001. Here, we demonstrate the use of clinical 1.5 MRI scanners as a feasible method for basic phenotyping in mice. These widely available scanners are capable of investigating in vivo infarct dimensions as well as assessment of cardiac functional parameters in mice with reasonable throughput.

  11. Neuroprotective effect of safranal, an active ingredient of Crocus sativus , in a rat model of transient cerebral ischemia

    Directory of Open Access Journals (Sweden)

    Hamid R. Sadeghnia

    2017-09-01

    Full Text Available Safranal is a monoterpene aldehyde found in saffron (Crocus sativus L. petals. It has been previously reported that safranal has a wide range of activities such as antioxidant and anti-inflammatory effects. In this study, we examined the effect of safranal on brain injuries in a transient model of focal cerebral ischemia. Transient focal cerebral ischemia was induced by middle cerebral artery occlusion for 30 min, followed by 24 h of reperfusion. Safranal in the doses of 72.5 and 145 mg/kg was administered intraperitoneally at 0, 3, and 6 h after reperfusion. Neurobehavioral deficit, infarct volume, hippocampal cell loss and markers of oxidative stress including thiobarbituric acid reactive substances (TBARS, total sulfhydryl (SH content, and antioxidant capacity (using FRAP assay were also assessed. The focal cerebral ischemia induced a significant increase in the neurological score, infarct volume and neuronal cell loss in the ipsilateral hippocampal CA1 and CA3 subfields (p < 0.001 and also oxidative stress markers (p < 0.01. Following safranal administration, the total SH content and antioxidant capacity significantly increased, while marked decreases were observed in the neurological score, infarct volume and hippocampal cell loss, as well as TBARS level. This study concluded that safranal had protective effects on ischemic reperfusion injury in the rat model of stroke. Such effects of safranal may have been exerted mainly by suppressing the production of free radicals and increasing antioxidant activity.

  12. Development of a modified model of spinal cord ischemia injury by selective ligation of lumbar arteries in rabbits.

    Science.gov (United States)

    Xiao, W; Wen, J; Huang, Y-C; Yu, B-S

    2017-11-01

    Experimental study. The aim of this study is to develop a modified model of spinal cord ischemia in rabbits. Shenzhen Key Laboratory of Spine Surgery, Shenzhen, China. In total, 20 New Zealand rabbits were divided into the following four groups according to the level of ligation of bilateral lumbar arteries: (1) group A, sham group, no ligation, n=5; (2) group B, ligation of bilateral lumbar arteries at three levels (L2-L4, n=5); (3) group C, ligation of bilateral lumbar arteries at four levels (L2-L5, n=5); and (4) group D, ligation of bilateral lumbar arteries at five levels (L1-L5, n=5). The latency of motor-evoked potentials was measured intraoperatively and the modified Tarlov grades were scored, followed by a histological observation of spinal cord, on the seventh day after surgery. All 10 rabbits in Group A and Group B were electrophysiologically, neurologically and histologically normal. In Group C, moderate spinal cord ischemia injury was found in three of five rabbits: they had prolonged latency of motor-evoked potentials and neuronal karyopyknosis in the anterior horn of spinal cord, and the average Tarlov score was 4.2±0.8. In Group D, severe spinal cord ischemia injury was recorded in all the five rabbits: the latency of motor-evoked potential prolonged in one rabbit, whereas the waveform disappeared in four rabbits; loss of neurons and vacuolation of gray matter were seen in spinal cord sections, and the average Tarlov score was 0.6±0.9. Selective ligation of lumbar arteries was a modified method to induce feasible and reproducible model of spinal cord ischemia in rabbits.

  13. Treatment with a nitric oxide-donating NSAID alleviates functional muscle ischemia in the mouse model of Duchenne muscular dystrophy.

    Science.gov (United States)

    Thomas, Gail D; Ye, Jianfeng; De Nardi, Claudio; Monopoli, Angela; Ongini, Ennio; Victor, Ronald G

    2012-01-01

    In patients with Duchenne muscular dystrophy (DMD) and the standard mdx mouse model of DMD, dystrophin deficiency causes loss of neuronal nitric oxide synthase (nNOSμ) from the sarcolemma, producing functional ischemia when the muscles are exercised. We asked if functional muscle ischemia would be eliminated and normal blood flow regulation restored by treatment with an exogenous nitric oxide (NO)-donating drug. Beginning at 8 weeks of age, mdx mice were fed a standard diet supplemented with 1% soybean oil alone or in combination with a low (15 mg/kg) or high (45 mg/kg) dose of HCT 1026, a NO-donating nonsteroidal anti-inflammatory agent which has previously been shown to slow disease progression in the mdx model. After 1 month of treatment, vasoconstrictor responses to intra-arterial norepinephrine (NE) were compared in resting and contracting hindlimbs. In untreated mdx mice, the usual effect of muscle contraction to attenuate NE-mediated vasoconstriction was impaired, resulting in functional ischemia: NE evoked similar decreases in femoral blood flow velocity and femoral vascular conductance (FVC) in the contracting compared to resting hindlimbs (ΔFVC contraction/ΔFVC rest=0.88 ± 0.03). NE-induced functional ischemia was unaffected by low dose HCT 1026 (ΔFVC ratio=0.92 ± 0.04; P>0.05 vs untreated), but was alleviated by the high dose of the drug (ΔFVC ratio=0.22 ± 0.03; Ptreatment up to 3 months. The effect of the NO-donating drug HCT 1026 to normalize blood flow regulation in contracting mdx mouse hindlimb muscles suggests a putative novel treatment for DMD. Further translational research is warranted.

  14. Optimal Designs for the Generalized Partial Credit Model

    OpenAIRE

    Bürkner, Paul-Christian; Schwabe, Rainer; Holling, Heinz

    2018-01-01

    Analyzing ordinal data becomes increasingly important in psychology, especially in the context of item response theory. The generalized partial credit model (GPCM) is probably the most widely used ordinal model and finds application in many large scale educational assessment studies such as PISA. In the present paper, optimal test designs are investigated for estimating persons' abilities with the GPCM for calibrated tests when item parameters are known from previous studies. We will derive t...

  15. Evaluation of potassium-43 scintillation images during early myocardial ischemia in an animal model

    International Nuclear Information System (INIS)

    Haider, B.; Oldewurtel, H.A.; Moschos, C.B.; Regan, T.J.

    1976-01-01

    To assess the validity of myocardial imaging with potassium-43 ( 43 K) early after the onset of ischemia, the left anterior descending artery was occluded with a balloon tip catheter in 32 intact anesthetized dogs. /sup 99m/Technetium ventriculograms localized the left ventricle. 43 K was administered intravenously and serial images were obtained in four views using an Anger camera with a pinhole collimator. The heart was arrested after 60 minutes and removed for imaging and tissue counts to ascertain extracardiac and geometric factors. In normals (group 1) left ventricular images were relatively homogeneous, except for the thin walled apex, both in vivo and in the isolated heart. Equilibration with 43 K prior to ischemia (group 2) gave similar images to group 1, associated with a small reduction in tissue counts after one hour of ischemia. Group 3 was infused with 43 K after initiation of ischemia. Despite a reduction of 43 K counts in the ischemic area to less than one-fourth of the nonischemic site (P < 0.001), demonstration of a ''cold area'' in vivo was inconstant, occurring in only 34 percent of studies. Lead shielding did not improve accuracy. In the isolated heart the ability to detect the cold area was improved to 73 percent. However, when the left ventricle was incised and spread flat, so that low and high activity areas were contiguous rather than superimposed, a widespread area of ischemia was present without exception in the anterior wall. Use of a rectilinear scanner in seven animals failed to improve diagnostic yield; areas of reduced radioactivity were seen at the apex in normals by both techniques. Thus, while detection of low flow areas in the isolated heart is feasible by isotopic imaging early after the onset of ischemia, both extracardiac and geometric factors can contribute to qualitative and quantitative errors in vivo

  16. Does Omegaven have beneficial effects on a rat model of ovarian ischemia/reperfusion?

    Science.gov (United States)

    Gungor, Ayse N Cakir; Turkon, Hakan; Albayrak, Aynur; Ovali, Mehmet; Islimye, Mine; Gencer, Meryem; Hacivelioglu, Servet; Cevizci, Sibel; Cesur, Ismet; Cosar, Emine

    2014-10-01

    The beneficial effects of omega-3 fatty acids on an intestinal ischemia/reperfusion (I/R) model was shown previously. Therefore, we aimed to examine the potential beneficial effects of parenteral omega-3 fatty acids, a safe and inexpensive product, on a rat model of ovarian I/R. A group of 39 rats was divided into six groups. Group 1 (Sham Group; n=6) underwent two laparotomies with a 3-h interval and their ovaries were removed 3h later. Group 2 (torsion-detorsion Group; n=7) had their ovaries torsioned clockwise and fixed at 720°; 3h later a detorsion operation was done and after another 3h, their ovaries were removed. Group 3 (n=7) and Group 4 (n=7) received the same treatment as Group 2; however, half an hour prior to detorsion, these rats received Omegaven at 1mL/kg and 5mL/kg, respectively. Group 5 (n=6) and Group 6 (n=6) received the same treatment as Group 1; however, half an hour prior to the second laparotomy, these rats received Omegaven at 1mL/kg and 5mL/kg, respectively. One ovary from each rat was evaluated histologically by hematoxylin and eosin (H&E) staining and the other ovary was homogenized and evaluated for total oxidant status (TOS), total antioxidant status (TAS) and oxidative stress index (OSI). While we failed to show any significant relationship among groups in oxidative parameters, there was a significant worsening in the torsion-detorsion group in histological evaluation. High Omegaven doses, but not low doses, improved tissue injury scores of torsioned and detorsioned ovaries to the levels observed in the control group. Omegaven improves the detrimental effects of ovarian I/R when used in sufficient doses. Its effects and dose adjustment on women with ovarian torsion must be investigated by further studies. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  17. Intraperitoneal curcumin decreased lung, renal and heart injury in abdominal aorta ischemia/reperfusion model in rat.

    Science.gov (United States)

    Aydin, Mehmet Salih; Caliskan, Ahmet; Kocarslan, Aydemir; Kocarslan, Sezen; Yildiz, Ali; Günay, Samil; Savik, Emin; Hazar, Abdussemet; Yalcin, Funda

    2014-01-01

    Previous studies have demonstrated that curcumin (CUR) has protective effects against ischemia reperfusion injury to various organs. We aimed to determine whether CUR has favorable effects on tissues and oxidative stress in abdominal aorta ischemia-reperfusion injury. Thirty rats were divided into three groups as sham, control and treatment (CUR) group. Control and CUR groups underwent abdominal aorta ischemia for 60 min followed by a 120 min period of reperfusion. In the CUR group, CUR was given 5 min before reperfusion at a dose of 200 mg/kg via an intraperitoneal route. Total antioxidant capacity (TAC), total oxidative status (TOS), and oxidative stress index (OSI) in blood serum were measured, and lung, renal and heart tissue histopathology were evaluated with light microscopy. TOS and OSI activity in blood samples were statistically decreased in sham and CUR groups compared to the control group (p OSI). Renal, lung, heart injury scores of sham and CUR groups were statistically decreased compared to control group (p model. Copyright © 2014 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

  18. Relations between CT perfusion parameters and degree of hepatic ischemia reperfusion injury in a rabbit model

    International Nuclear Information System (INIS)

    Guo Chengwei; Shen Sandi; Yi Xianlin; Zhang Zhonglin; Liu Zaiyi; Liang Changhong

    2011-01-01

    Objective: To observe the changes of hepatic CT perfusion parameters and their correlation with serum aspartate transaminase (AST), alanine transaminase (ALT) and alkaline phosphatase (ALP) in a rabbit hepatic ischemia reperfusion injury (IRI) model. Methods: Hepatic IRI was produced in rabbits by inducing left liver lobe ischemia (60 min) followed by 6 h, 12 h and 24 h reperfusion (6 rabbits were used for each reperfusion interval). Additional 6 rabbits were served as sham-operated controls. All the rabbits were scanned with a dynamic iCT protocol. Blood samples were taken from the superior mesenteric vein to measure the levels of serum amylase (ALT, AST, and ALP) in various groups, and liver samples were taken for histological examinations after scanning. One-way analysis of variance (ANOVA) was used to determine differences between groups. The correlations of CT perfusion parameters with serum levels were analyzed using Pearson correlation coefficient. Results: Heterogeneity of CT perfusion patterns appeared in the 6 h groups, which presented as low enhanced area [(25.1±9.3) ml · min -1 · 100 mg -1 ]. In reduced perfusion regions of IRI group, HAP of 12 h IRI group [(19.5± 13.6) ml · min -1 · 100 mg -1 ], 24 h IRI group (8.0±2.7) ml · min -1 · 100 mg -1 ], HPP of 6 h IRI group [(10.8±5.5) ml · min -1 · 100 mg -1 ], 12 h IRI group [(14.4±5.2) ml · min -1 · 100 mg -1 ] , 24 h IRI group [(7.8±3.3) ml · min -1 · 100 mg -1 ] and TLP of 6 h IRI group [(35.9±14.0) ml · min -1 · 100 mg -1 ], 12 h IRI group [(33.9±16.1) ml · min -1 · 100 mg -1 ], 24 h IRI group [(16.0± 5.5) ml · min -1 · 100 mg -1 ] were lower than those of sham group [HAP (21.2±10.5) ml · min -1 · 100 mg -1 , HPP (63.5±24.0) ml · min -1 · 100 mg -1 , TLP (81.4±24.8) ml · min -1 · 100 mg -1 ] (F=8.376, 25.950, 16.925, P<0.01). However, HPI of 6 h IRI group [(65.9±3.9)%], 12 h IRI group [(54.2±16.7)%], and 24 h IRI group [(48.9±10.0)%] were higher compared to sham

  19. Aging aggravates long-term renal ischemia-reperfusion injury in a rat model.

    Science.gov (United States)

    Xu, Xianlin; Fan, Min; He, Xiaozhou; Liu, Jipu; Qin, Jiandi; Ye, Jianan

    2014-03-01

    Ischemia-reperfusion injury (IRI) has been considered as the major cause of acute kidney injury and can result in poor long-term graft function. Functional recovery after IRI is impaired in the elderly. In the present study, we aimed to compare kidney morphology, function, oxidative stress, inflammation, and development of renal fibrosis in young and aged rats after renal IRI. Rat models of warm renal IRI were established by clamping left pedicles for 45 min after right nephrectomy, then the clamp was removed, and kidneys were reperfused for up to 12 wk. Biochemical and histologic renal damage were assessed at 12 wk after reperfusion. The immunohistochemical staining of monocyte macrophage antigen-1 (ED-1) and transforming growth factor beta 1 (TGF-β1) and messenger RNA level of TGF-β1 in the kidney were analyzed. Renal IRI caused significant increases of malondialdehyde and 8-hydroxydeoxyguanosine levels and a decrease of superoxide dismutase activity in young and aged IRI rats; however, these changes were more obvious in the aged rats. IRI resulted in severe inflammation and tubulointerstitial fibrosis with decreased creatinine (Cr) clearance and increased histologic damage in aged rats compared with young rats. Moreover, we measured the ratio of Cr clearance between young and aged IRI rats. It demonstrated that aged IRI rats did have poor Cr clearance compared with the young IRI rats. ED-1 and TGF-β1 expression levels in the kidney were significantly higher in aged rats than in young rats after IRI. Aged rats are more susceptible to IRI-induced renal failure, which may associate with the increased oxidative stress, increased histologic damage, and increased inflammation and tubulointerstitial fibrosis. Targeting oxidative stress and inflammatory response should improve the kidney recovery after IRI. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Estimating varying coefficients for partial differential equation models.

    Science.gov (United States)

    Zhang, Xinyu; Cao, Jiguo; Carroll, Raymond J

    2017-09-01

    Partial differential equations (PDEs) are used to model complex dynamical systems in multiple dimensions, and their parameters often have important scientific interpretations. In some applications, PDE parameters are not constant but can change depending on the values of covariates, a feature that we call varying coefficients. We propose a parameter cascading method to estimate varying coefficients in PDE models from noisy data. Our estimates of the varying coefficients are shown to be consistent and asymptotically normally distributed. The performance of our method is evaluated by a simulation study and by an empirical study estimating three varying coefficients in a PDE model arising from LIDAR data. © 2017, The International Biometric Society.

  1. Anatomic partial nephrectomy: technique evolution.

    Science.gov (United States)

    Azhar, Raed A; Metcalfe, Charles; Gill, Inderbir S

    2015-03-01

    Partial nephrectomy provides equivalent long-term oncologic and superior functional outcomes as radical nephrectomy for T1a renal masses. Herein, we review the various vascular clamping techniques employed during minimally invasive partial nephrectomy, describe the evolution of our partial nephrectomy technique and provide an update on contemporary thinking about the impact of ischemia on renal function. Recently, partial nephrectomy surgical technique has shifted away from main artery clamping and towards minimizing/eliminating global renal ischemia during partial nephrectomy. Supported by high-fidelity three-dimensional imaging, novel anatomic-based partial nephrectomy techniques have recently been developed, wherein partial nephrectomy can now be performed with segmental, minimal or zero global ischemia to the renal remnant. Sequential innovations have included early unclamping, segmental clamping, super-selective clamping and now culminating in anatomic zero-ischemia surgery. By eliminating 'under-the-gun' time pressure of ischemia for the surgeon, these techniques allow an unhurried, tightly contoured tumour excision with point-specific sutured haemostasis. Recent data indicate that zero-ischemia partial nephrectomy may provide better functional outcomes by minimizing/eliminating global ischemia and preserving greater vascularized kidney volume. Contemporary partial nephrectomy includes a spectrum of surgical techniques ranging from conventional-clamped to novel zero-ischemia approaches. Technique selection should be tailored to each individual case on the basis of tumour characteristics, surgical feasibility, surgeon experience, patient demographics and baseline renal function.

  2. Dynamic myocardial perfusion in a porcine balloon-induced ischemia model using a prototype spectral detector CT

    Science.gov (United States)

    Fahmi, Rachid; Eck, Brendan L.; Fares, Anas; Levi, Jacob; Wu, Hao; Vembar, Mani; Dhanantwari, Amar; Bezerra, Hiram G.; Wilson, David L.

    2015-03-01

    Myocardial CT perfusion (CTP) imaging is an application that should greatly benefit from spectral CT through the significant reduction of beam hardening (BH) artifacts using mono-energetic (monoE) image reconstructions. We used a prototype spectral detector CT (SDCT) scanner (Philips Healthcare) and developed advanced processing tools (registration, segmentation, and deconvolution-based flow estimation) for quantitative myocardial CTP in a porcine ischemia model with different degrees of coronary occlusion using a balloon catheter. The occlusion severity was adjusted with fractional flow reserve (FFR) measurements. The SDCT scanner is a single source, dual-layer detector system, which allows simultaneous acquisitions of low and high energy projections, hence enabling accurate projection-based material decomposition and effective reduction of BH-artifacts. In addition, the SDCT scanner eliminates partial scan artifacts with fast (0.27s), full gantry rotation acquisitions. We acquired CTP data under different hemodynamic conditions and reconstructed conventional 120kVp images and projection-based monoenergetic (monoE) images for energies ranging from 55keV-to-120keV. We computed and compared myocardial blood flow (MBF) between different reconstructions. With balloon completely deflated (FFR=1), we compared the mean attenuation in a myocardial region of interest before iodine arrival and at peak iodine enhancement in the left ventricle (LV), and we found that monoE images at 70keV effectively minimized the difference in attenuation, due to BH, to less than 1 HU compared to 14 HU with conventional 120kVp images. Flow maps under baseline condition (FFR=1) were more uniform throughout the myocardial wall at 70keV, whereas with 120kVp data about 12% reduction in blood flow was noticed on BH-hypoattenuated areas compared to other myocardial regions. We compared MBF maps at different keVs under an ischemic condition (FFR < 0.7), and we found that flow

  3. Effects of Scrambling trumpet Creeper flavone on transient cerebral ischemia model (TIA) in rats.

    Science.gov (United States)

    Miao, Mingsan; Zhang, Xu; Zhang, Fan; Wang, Can; Fang, Xiaoyan; Bai, Ming; Xu, Cuishan; Teng, Leshang

    2018-03-01

    To investigate the effects of Scrambling Trumpet Creeper flavone on neurological function score, brain tissue lesion and related biochemical indexes in rat TIA model. Methods: TIA model was induced by tail vein injection of t-butanol (t-BHP). The rats in each administration group were given large, medium and low dose of Scrambling Trumpet Creeper flavone 0.1% CMC suspension, nimodipine and Yangxueqingnao particles group 0.1% CMC suspension, model group and blank group fed the same volume 0.1% CMC. Once a day, continuous administration of 7d. On the 3rd and 6th day after administration, t-BHP was injected into the tail vein, and then placed in a sealed 1 L jar. After 10 min of hypoxia, the neurological function score (NDS) was performed. After the first 2 days of TIA administration, the hem rheology was measured immediately after 1 h of administration, and blood rheology was measured immediately after the administration of blood, blood clotting, hematocrit, hematocrit and whole blood viscosity. After HE is staining to observe the pathological changes of hippocampus and cortex in the left-brain tissue. (LDH) and adenosine triphosphate (ATP) were measured. The right brain tissue of the cerebral cortex was observed. The expression of lactate (LD), lactate dehydrogenase (LDH) Fibroblast growth factor (FGF) and insulin growth factor (IGF) were detected by immunohistochemistry. Compared with the blank group, the coagulation time of the model rats was significantly shortened. The red blood cell deformation index was significantly decreased. Erythrocyte sedimentation rate, hematocrit, plasma viscosity, whole blood viscosity, erythrocyte rigidity index and blood sedimentation equation K value were significantly increased; LD content increased significantly, and LDH, ATP enzyme activity decreased significantly. The positive expression of FGF and IGF in the cortical area had a trend of increasing. The Scrambling Trumpet Creeper flavone significantly improved the

  4. Effects of Scrambling trumpet Creeper flavone on transient cerebral ischemia model (TIA in rats

    Directory of Open Access Journals (Sweden)

    Mingsan Miao

    2018-03-01

    Full Text Available To investigate the effects of Scrambling Trumpet Creeper flavone on neurological function score, brain tissue lesion and related biochemical indexes in rat TIA model. Methods: TIA model was induced by tail vein injection of t-butanol (t-BHP. The rats in each administration group were given large, medium and low dose of Scrambling Trumpet Creeper flavone 0.1% CMC suspension, nimodipine and Yangxueqingnao particles group 0.1% CMC suspension, model group and blank group fed the same volume 0.1% CMC. Once a day, continuous administration of 7d. On the 3rd and 6th day after administration, t-BHP was injected into the tail vein, and then placed in a sealed 1 L jar. After 10 min of hypoxia, the neurological function score (NDS was performed. After the first 2 days of TIA administration, the hem rheology was measured immediately after 1 h of administration, and blood rheology was measured immediately after the administration of blood, blood clotting, hematocrit, hematocrit and whole blood viscosity. After HE is staining to observe the pathological changes of hippocampus and cortex in the left-brain tissue. (LDH and adenosine triphosphate (ATP were measured. The right brain tissue of the cerebral cortex was observed. The expression of lactate (LD, lactate dehydrogenase (LDH Fibroblast growth factor (FGF and insulin growth factor (IGF were detected by immunohistochemistry. Results: Compared with the blank group, the coagulation time of the model rats was significantly shortened. The red blood cell deformation index was significantly decreased. Erythrocyte sedimentation rate, hematocrit, plasma viscosity, whole blood viscosity, erythrocyte rigidity index and blood sedimentation equation K value were significantly increased; LD content increased significantly, and LDH, ATP enzyme activity decreased significantly. The positive expression of FGF and IGF in the cortical area had a trend of increasing. Conclusion: The Scrambling Trumpet Creeper flavone

  5. Protective Effects of Sodium (±-5-Bromo-2-(α-Hydroxypentyl Benzoate in a Rodent Model of Global Cerebral Ischemia

    Directory of Open Access Journals (Sweden)

    Yuan Gao

    2017-09-01

    Full Text Available The aim of the current study was to explore the protective effects of sodium (±-5-bromo-2-(α-hydroxypentyl benzoate (brand name: brozopine, BZP in a rat model of global cerebral ischemia. The rat model was established using a modified Winocur’s method; close postoperative observation was conducted at all times. Neurological function was detected through prehensile traction and beam-walking test. BZP reduced mortality and prolonged the survival time of rats with global cerebral ischemia, within 24 h. There was a decreased survival rate (60% in the Model group, while the survival rate of the BZP (3 and 12 mg/kg remarkably increased the survival rate (to 80 and 90%, respectively, in a dose-dependent manner. Compared with the Model group (survival time: 18.50 h, the administration of BZP (0.75, 3, and 12 mg/kg prolonged the survival time (to 20.38, 21.85, and 23.90 h, respectively, particularly in BZP 12 mg/kg group (P < 0.05. Additionally, the BZP (12 mg/kg group exhibited an improvement in their motor function (P < 0.05. The BZP groups (0.75, 3, and 12 mg/kg displayed significantly reduced necrosis and the percentage of apoptotic cells (P < 0.05 and P < 0.01, respectively. Compared with Model group, BZP (0.75, 3, and 12 mg/kg increased the NeuN optical density values (P < 0.01. Rats with global ischemia had a high expression of Cyt-c, caspase-3, and the Bax/Bcl-2 ratio compared with sham group (P < 0.01. BZP (0.75, 3, and 12 mg/kg, however, reduced the expression of Cyt-c, caspase-3, and the Bax/Bcl-2 ratio, in a dose-dependent manner (P < 0.01. There was low expression of p-Akt and PI3K in Model group, compared with the sham group (P < 0.01. Meanwhile, BZP (0.75, 3, and 12 mg/kg increased the expression of p-Akt and PI3K in a dose-dependent manner (P < 0.01. We also found the expression of Cyt-c, caspase-3, Bax/Bcl-2 ratio, PI3K, p-Akt, and comprehensive score were directly related. In conclusion, BZP had therapeutic potential and prevented

  6. Neurotherapeutic activity of the recombinant heat shock protein Hsp70 in a model of focal cerebral ischemia in rats

    Directory of Open Access Journals (Sweden)

    Shevtsov MA

    2014-05-01

    Full Text Available Maxim A Shevtsov,1,2 Boris P Nikolaev,3 Ludmila Y Yakovleva,3 Anatolii V Dobrodumov,4 Anastasiy S Dayneko,5 Alexey A Shmonin,5,6 Timur D Vlasov,5 Elena V Melnikova,5 Alexander D Vilisov,4,5 Irina V Guzhova,1 Alexander M Ischenko,3 Anastasiya L Mikhrina,7 Oleg V Galibin,5 Igor V Yakovenko,2 Boris A Margulis1 1Institute of Cytology of the Russian Academy of Sciences (RAS, St Petersburg, Russia; 2AL Polenov Russian Research Scientific Institute of Neurosurgery, St Petersburg, Russia; 3Research Institute of Highly Pure Biopreparations, St Petersburg, Russia; 4Institute of Macromolecular Compounds of the Russian Academy of Sciences (RAS, St Petersburg, Russia; 5First St Petersburg IP Pavlov State Medical University, St Petersburg, Russia; 6Federal Almazov Medical Research Centre, St Petersburg, Russia; 7IM Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences (RAS, St Petersburg, Russia Abstract: Recombinant 70 kDa heat shock protein (Hsp70 is an antiapoptotic protein that has a cell protective activity in stress stimuli and thus could be a useful therapeutic agent in the management of patients with acute ischemic stroke. The neuroprotective and neurotherapeutic activity of recombinant Hsp70 was explored in a model of experimental stroke in rats. Ischemia was produced by the occlusion of the middle cerebral artery for 45 minutes. To assess its neuroprotective capacity, Hsp70, at various concentrations, was intravenously injected 20 minutes prior to ischemia. Forty-eight hours after ischemia, rats were sacrificed and brain tissue sections were stained with 2% triphenyl tetrazolium chloride. Preliminary treatment with Hsp70 significantly reduced the ischemic zone (optimal response at 2.5 mg/kg. To assess Hsp70’s neurotherapeutic activity, we intravenously administered Hsp70 via the tail vein 2 hours after reperfusion (2 hours and 45 minutes after ischemia. Rats were then kept alive for 72 hours. The

  7. Emulating facial biomechanics using multivariate partial least squares surrogate models.

    Science.gov (United States)

    Wu, Tim; Martens, Harald; Hunter, Peter; Mithraratne, Kumar

    2014-11-01

    A detailed biomechanical model of the human face driven by a network of muscles is a useful tool in relating the muscle activities to facial deformations. However, lengthy computational times often hinder its applications in practical settings. The objective of this study is to replace precise but computationally demanding biomechanical model by a much faster multivariate meta-model (surrogate model), such that a significant speedup (to real-time interactive speed) can be achieved. Using a multilevel fractional factorial design, the parameter space of the biomechanical system was probed from a set of sample points chosen to satisfy maximal rank optimality and volume filling. The input-output relationship at these sampled points was then statistically emulated using linear and nonlinear, cross-validated, partial least squares regression models. It was demonstrated that these surrogate models can mimic facial biomechanics efficiently and reliably in real-time. Copyright © 2014 John Wiley & Sons, Ltd.

  8. semPLS: Structural Equation Modeling Using Partial Least Squares

    Directory of Open Access Journals (Sweden)

    Armin Monecke

    2012-05-01

    Full Text Available Structural equation models (SEM are very popular in many disciplines. The partial least squares (PLS approach to SEM offers an alternative to covariance-based SEM, which is especially suited for situations when data is not normally distributed. PLS path modelling is referred to as soft-modeling-technique with minimum demands regarding mea- surement scales, sample sizes and residual distributions. The semPLS package provides the capability to estimate PLS path models within the R programming environment. Different setups for the estimation of factor scores can be used. Furthermore it contains modular methods for computation of bootstrap confidence intervals, model parameters and several quality indices. Various plot functions help to evaluate the model. The well known mobile phone dataset from marketing research is used to demonstrate the features of the package.

  9. Dynamic CT myocardial perfusion imaging: detection of ischemia in a porcine model with FFR verification

    Science.gov (United States)

    Fahmi, Rachid; Eck, Brendan L.; Vembar, Mani; Bezerra, Hiram G.; Wilson, David L.

    2014-03-01

    Dynamic cardiac CT perfusion (CTP) is a high resolution, non-invasive technique for assessing myocardial blood ow (MBF), which in concert with coronary CT angiography enable CT to provide a unique, comprehensive, fast analysis of both coronary anatomy and functional ow. We assessed perfusion in a porcine model with and without coronary occlusion. To induce occlusion, each animal underwent left anterior descending (LAD) stent implantation and angioplasty balloon insertion. Normal ow condition was obtained with balloon completely de ated. Partial occlusion was induced by balloon in ation against the stent with FFR used to assess the extent of occlusion. Prospective ECG-triggered partial scan images were acquired at end systole (45% R-R) using a multi-detector CT (MDCT) scanner. Images were reconstructed using FBP and a hybrid iterative reconstruction (iDose4, Philips Healthcare). Processing included: beam hardening (BH) correction, registration of image volumes using 3D cubic B-spline normalized mutual-information, and spatio-temporal bilateral ltering to reduce partial scan artifacts and noise variation. Absolute blood ow was calculated with a deconvolutionbased approach using singular value decomposition (SVD). Arterial input function was estimated from the left ventricle (LV) cavity. Regions of interest (ROIs) were identi ed in healthy and ischemic myocardium and compared in normal and occluded conditions. Under-perfusion was detected in the correct LAD territory and ow reduction agreed well with FFR measurements. Flow was reduced, on average, in LAD territories by 54%.

  10. Hidden physics models: Machine learning of nonlinear partial differential equations

    Science.gov (United States)

    Raissi, Maziar; Karniadakis, George Em

    2018-03-01

    While there is currently a lot of enthusiasm about "big data", useful data is usually "small" and expensive to acquire. In this paper, we present a new paradigm of learning partial differential equations from small data. In particular, we introduce hidden physics models, which are essentially data-efficient learning machines capable of leveraging the underlying laws of physics, expressed by time dependent and nonlinear partial differential equations, to extract patterns from high-dimensional data generated from experiments. The proposed methodology may be applied to the problem of learning, system identification, or data-driven discovery of partial differential equations. Our framework relies on Gaussian processes, a powerful tool for probabilistic inference over functions, that enables us to strike a balance between model complexity and data fitting. The effectiveness of the proposed approach is demonstrated through a variety of canonical problems, spanning a number of scientific domains, including the Navier-Stokes, Schrödinger, Kuramoto-Sivashinsky, and time dependent linear fractional equations. The methodology provides a promising new direction for harnessing the long-standing developments of classical methods in applied mathematics and mathematical physics to design learning machines with the ability to operate in complex domains without requiring large quantities of data.

  11. A Metabolite-Sensitive, Thermodynamically Constrained Model of Cardiac Cross-Bridge Cycling: Implications for Force Development during Ischemia

    KAUST Repository

    Tran, Kenneth; Smith, Nicolas P.; Loiselle, Denis S.; Crampin, Edmund J.

    2010-01-01

    We present a metabolically regulated model of cardiac active force generation with which we investigate the effects of ischemia on maximum force production. Our model, based on a model of cross-bridge kinetics that was developed by others, reproduces many of the observed effects of MgATP, MgADP, Pi, and H(+) on force development while retaining the force/length/Ca(2+) properties of the original model. We introduce three new parameters to account for the competitive binding of H(+) to the Ca(2+) binding site on troponin C and the binding of MgADP within the cross-bridge cycle. These parameters, along with the Pi and H(+) regulatory steps within the cross-bridge cycle, were constrained using data from the literature and validated using a range of metabolic and sinusoidal length perturbation protocols. The placement of the MgADP binding step between two strongly-bound and force-generating states leads to the emergence of an unexpected effect on the force-MgADP curve, where the trend of the relationship (positive or negative) depends on the concentrations of the other metabolites and [H(+)]. The model is used to investigate the sensitivity of maximum force production to changes in metabolite concentrations during the development of ischemia.

  12. Melt migration modeling in partially molten upper mantle

    Science.gov (United States)

    Ghods, Abdolreza

    The objective of this thesis is to investigate the importance of melt migration in shaping major characteristics of geological features associated with the partial melting of the upper mantle, such as sea-floor spreading, continental flood basalts and rifting. The partial melting produces permeable partially molten rocks and a buoyant low viscosity melt. Melt migrates through the partially molten rocks, and transfers mass and heat. Due to its much faster velocity and appreciable buoyancy, melt migration has the potential to modify dynamics of the upwelling partially molten plumes. I develop a 2-D, two-phase flow model and apply it to investigate effects of melt migration on the dynamics and melt generation of upwelling mantle plumes and focusing of melt migration beneath mid-ocean ridges. Melt migration changes distribution of the melt-retention buoyancy force and therefore affects the dynamics of the upwelling plume. This is investigated by modeling a plume with a constant initial melt of 10% where no further melting is considered. Melt migration polarizes melt-retention buoyancy force into high and low melt fraction regions at the top and bottom portions of the plume and therefore results in formation of a more slender and faster upwelling plume. Allowing the plume to melt as it ascends through the upper mantle also produces a slender and faster plume. It is shown that melt produced by decompressional melting of the plume migrates to the upper horizons of the plume, increases the upwelling velocity and thus, the volume of melt generated by the plume. Melt migration produces a plume which lacks the mushroom shape observed for the plume models without melt migration. Melt migration forms a high melt fraction layer beneath the sloping base of the impermeable oceanic lithosphere. Using realistic conditions of melting, freezing and melt extraction, I examine whether the high melt fraction layer is able to focus melt from a wide partial melting zone to a narrow region

  13. Optimal Retail Price Model for Partial Consignment to Multiple Retailers

    Directory of Open Access Journals (Sweden)

    Po-Yu Chen

    2017-01-01

    Full Text Available This paper investigates the product pricing decision-making problem under a consignment stock policy in a two-level supply chain composed of one supplier and multiple retailers. The effects of the supplier’s wholesale prices and its partial inventory cost absorption of the retail prices of retailers with different market shares are investigated. In the partial product consignment model this paper proposes, the seller and the retailers each absorb part of the inventory costs. This model also provides general solutions for the complete product consignment and the traditional policy that adopts no product consignment. In other words, both the complete consignment and nonconsignment models are extensions of the proposed model (i.e., special cases. Research results indicated that the optimal retail price must be between 1/2 (50% and 2/3 (66.67% times the upper limit of the gross profit. This study also explored the results and influence of parameter variations on optimal retail price in the model.

  14. Detection of vascular cell adhesion molecule-1 expression with USPIO-enhanced molecular MRI in a mouse model of cerebral ischemia

    International Nuclear Information System (INIS)

    Frechou, M.; Beray-Berthat, V.; Plotkine, M.; Marchand-Leroux, C.; Margaill, I.; Raynaud, J.S.; Gombert, F.; Lancelot, E.; Ballet, S.; Robert, P.; Louin, G.; Meriaux, S.

    2013-01-01

    Vascular damage plays a critical role after stroke, leading notably to edema, hemorrhages and stroke recurrence. Tools to characterize the vascular lesion are thus a real medical need. In this context, the specific nano-particular contrast agent P03011, an USPIO (ultra-small superparamagnetic iron oxide) conjugated to a peptide that targets VCAM-1 (vascular cell adhesion molecule-1), was developed to detect this major component of the vascular inflammatory response. This study aimed to make the proof of concept of the capacity of this targeted USPIO to detect VCAM-1 with MRI after cerebral ischemia in mouse. The time course of VCAM-1 expression was first examined by immunohistochemistry in our model of cerebral ischemia-reperfusion. Secondly, P03011 or non-targeted USPIO P03007 were injected 5 h after ischemia (100 mmol iron kg -1 ; i.v.) and in vivo and ex vivo MRI were performed 24 h after ischemia onset. Double labeling immunofluorescence was then performed on brain slices in order to detect both USPIO and VCAM-1. VCAM-1 expression was significantly up-regulated 24 h after ischemia in our model. In animals receiving P03011, both in vivo and ex vivo MRI performed 24 h after ischemia onset showed hypointense foci which could correspond to iron particles. Histological analysis showed a co-localization of the targeted USPIO and VCAM-1. This study demonstrates that VCAM-1 detection is possible with the USPIO P03011 in a model of cerebral ischemia. This kind of contrast agent could be an interesting clinical tool to characterize ischemic lesions in terms of vascular damage. (authors)

  15. Imaging of Acute Mesenteric Ischemia Using Multidetector CT and CT Angiography in a Porcine Model

    OpenAIRE

    Rosow, David E.; Sahani, Dushyant; Strobel, Oliver; Kalva, Sanjeeva; Mino-Kenudson, Mari; Holalkere, Nagaraj S.; Alsfasser, Guido; Saini, Sanjay; Lee, Susanna I.; Mueller, Peter R.; Castillo, Carlos Fernández-del; Warshaw, Andrew L.; Thayer, Sarah P.

    2005-01-01

    Acute mesenteric ischemia, a frequently lethal disease, requires prompt diagnosis and intervention for favorable clinical outcomes. This goal remains elusive due, in part, to lack of a noninvasive and accurate imaging study. Traditional angiography is the diagnostic gold standard but is invasive and costly. Computed tomography (CT) is readily available and noninvasive but has shown variable success in diagnosing this disease. The faster scanning time of multidetector row CT (M.D.CT) greatly f...

  16. Mechanisms of angiogenesis in a Curculigoside A-treated rat model of cerebral ischemia and reperfusion injury

    International Nuclear Information System (INIS)

    Zhu, Haibo; He, Jie; Ye, Liang; Lin, Fei; Hou, Jian; Zhong, Yan; Jiang, Wanglin

    2015-01-01

    Curculigoside A has shown protective effects against rat cortical neuron damage in vivo. However, the molecular mechanisms through which Curculigoside A affords this protection are unclear. In the present study, we sought to elucidate the mechanisms of angiogenesis in rat aortic endothelial cells (RAEC), rat aortic smooth muscle cells (RASMC) as well as a rat model of cerebral ischemia and reperfusion injury following treatment with Curculigoside A. We examined the role of Curculigoside A on RAEC and RASMC proliferation, migration, and tube formation in vitro and in a cerebral ischemia and reperfusion injury rat model. We used the recombinant Dickkopf (DKK)-1 protein, a Wnt/β-catenin inhibitor, and the recombinant WIF-1 protein, a Wnt5a antagonist to determine mechanisms. In addition, we measured leakage of the blood–brain barrier (BBB) and tested for angiogenesis associated proteins. Our data suggest that Curculigoside A induces angiogenesis in vitro by increasing proliferation, migration and tube formation in RAEC and RASMC. The increase in Curculigoside A-induced proliferation and tube formation was counteracted by DKK-1 and WIF-1. Curculigoside A increased expression of VEGF, p-VEGFR, p-CREB, Egr-3, VCAM-1, Ang1 and Tie2 while prohibiting BBB leakage in cerebral ischemia and reperfusion injured rats. However, Cyclosporine A, a CREB inhibitor, reduced the expression of p-CREB, Egr-3, VCAM-1, Ang1 and Tie2. These data suggest that Curculigoside A induces cell proliferation and angiogenesis through the Wnt5a/β-catenin and VEGF/CREB/Egr-3/VCAM-1 signaling axis and promotes maturation and stability of new blood vessels via increasing Ang1 and Tie-2 expression. - Highlights: • Curculigoside A induces cell proliferation through Wnt5a/β-catenin pathway. • Curculigoside A induces angiogenesis via VEGF/CREB/Egr-3/VCAM-1 signaling axis. • Curculigoside A promotes blood vessel maturation via Ang1/Tie2 pathway.

  17. In Vivo MR Imaging of Magnetically Labeled Mesenchymal Stem Cells in a Rat Model of Renal Ischemia

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Sung Il [Konkuk University Medical Center, Seoul (Korea, Republic of); Kim, Seung Hyup [Seoul National University Medical Research Center, Seoul (Korea, Republic of); Kim, Hyo Cheol; Chung, Se Young; Moon, Woo Kyung; Kim, Hoe Suk [Seoul National University Hospital, Seoul (Korea, Republic of); Choi, Jong Sun [Dongguk University International Hospital, Goyang (Korea, Republic of); Moon, Min Hoan [Cheil General Hospital and Women' s Healthcare Center, Seoul (Korea, Republic of); Son, Kyu Ri; Sung, Chang Kyu [Seoul National University Boramae Hospital, Seoul (Korea, Republic of)

    2009-06-15

    This study was designed to evaluate in vivo MR imaging for the depiction of intraarterially injected superparamagnetic iron oxide (SPIO)-labeled mesenchymal stem cells (MSCs) in an experimental rat model of renal ischemia. Left renal ischemia was induced in 12 male Sprague- Dawley rats by use of the catheter lodging method. In vivo MR signal intensity variations depicted on T2*-weighted sequences were evaluated in both the left and right kidneys prior to injection (n = 2), two hours (n = 4), 15 hours (n = 2), 30 hours (n = 2) and 72 hours (n = 2) after injection of SPIO-labeled MSCs in both kidneys. Signal intensity variations were correlated with the number of Prussian blue stain-positive cells as visualized in histological specimens. In an in vivo study, it was determined that there was a significant difference in signal intensity variation for both the left and right cortex (40.8 {+-} 4.12 and 26.4 {+-} 7.92, respectively) and for both the left and right medulla (23.2 {+-} 3.32 and 15.2 {+-} 3.31, respectively) until two hours after injection (p < 0.05). In addition, signal intensity variation in the left renal cortex was well correlated with the number of Prussian blue stain-positive cells per high power field (r = 0.98, p < 0.05). Intraarterial injected SPIO-labeled MSCs in an experimental rat model of renal ischemia can be detected with the use of in vivo MR imaging immediately after injection.

  18. Effects of Acute Systemic Hypoxia and Hypercapnia on Brain Damage in a Rat Model of Hypoxia-Ischemia.

    Directory of Open Access Journals (Sweden)

    Wanchao Yang

    Full Text Available Therapeutic hypercapnia has the potential for neuroprotection after global cerebral ischemia. Here we further investigated the effects of different degrees of acute systemic hypoxia in combination with hypercapnia on brain damage in a rat model of hypoxia and ischemia. Adult wistar rats underwent unilateral common carotid artery (CCA ligation for 60 min followed by ventilation with normoxic or systemic hypoxic gas containing 11%O2,13%O2,15%O2 and 18%O2 (targeted to PaO2 30-39 mmHg, 40-49 mmHg, 50-59 mmHg, and 60-69 mmHg, respectively or systemic hypoxic gas containing 8% carbon dioxide (targeted to PaCO2 60-80 mmHg for 180 min. The mean artery pressure (MAP, blood gas, and cerebral blood flow (CBF were evaluated. The cortical vascular permeability and brain edema were examined. The ipsilateral cortex damage and the percentage of hippocampal apoptotic neurons were evaluated by Nissl staining and terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate-biotin nick end labeling (TUNEL assay as well as flow cytometry, respectively. Immunofluorescence and western blotting were performed to determine aquaporin-4 (AQP4 expression. In rats treated with severe hypoxia (PaO2 50 mmHg, hypercapnia protected against these pathophysiological changes. Moreover, hypercapnia treatment significantly reduced brain damage in the ischemic ipsilateral cortex and decreased the percentage of apoptotic neurons in the hippocampus after the CCA ligated rats were exposed to mild or moderate hypoxemia (PaO2 > 50 mmHg; especially under mild hypoxemia (PaO2 > 60 mmHg, hypercapnia significantly attenuated the expression of AQP4 protein with brain edema (p < 0.05. Hypercapnia exerts beneficial effects under mild to moderate hypoxemia and augments detrimental effects under severe hypoxemia on brain damage in a rat model of hypoxia-ischemia.

  19. Mechanisms of angiogenesis in a Curculigoside A-treated rat model of cerebral ischemia and reperfusion injury

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Haibo [School of Public Health and Management, Binzhou Medical University, Yantai (China); Institute of Toxicology, Binzhou Medical University, Yantai (China); He, Jie [State Key Laboratory of Long-acting Targeting Drug Delivery Technologies (Luye Pharma Group Ltd.), Yantai 264003 (China); Ye, Liang [School of Public Health and Management, Binzhou Medical University, Yantai (China); Institute of Toxicology, Binzhou Medical University, Yantai (China); Lin, Fei; Hou, Jian; Zhong, Yan [State Key Laboratory of Long-acting Targeting Drug Delivery Technologies (Luye Pharma Group Ltd.), Yantai 264003 (China); Jiang, Wanglin, E-mail: jwl518@163.com [School of Pharmaceutical Sciences, Institute of Materia Medica, Binzhou Medical University, Yantai (China)

    2015-11-01

    Curculigoside A has shown protective effects against rat cortical neuron damage in vivo. However, the molecular mechanisms through which Curculigoside A affords this protection are unclear. In the present study, we sought to elucidate the mechanisms of angiogenesis in rat aortic endothelial cells (RAEC), rat aortic smooth muscle cells (RASMC) as well as a rat model of cerebral ischemia and reperfusion injury following treatment with Curculigoside A. We examined the role of Curculigoside A on RAEC and RASMC proliferation, migration, and tube formation in vitro and in a cerebral ischemia and reperfusion injury rat model. We used the recombinant Dickkopf (DKK)-1 protein, a Wnt/β-catenin inhibitor, and the recombinant WIF-1 protein, a Wnt5a antagonist to determine mechanisms. In addition, we measured leakage of the blood–brain barrier (BBB) and tested for angiogenesis associated proteins. Our data suggest that Curculigoside A induces angiogenesis in vitro by increasing proliferation, migration and tube formation in RAEC and RASMC. The increase in Curculigoside A-induced proliferation and tube formation was counteracted by DKK-1 and WIF-1. Curculigoside A increased expression of VEGF, p-VEGFR, p-CREB, Egr-3, VCAM-1, Ang1 and Tie2 while prohibiting BBB leakage in cerebral ischemia and reperfusion injured rats. However, Cyclosporine A, a CREB inhibitor, reduced the expression of p-CREB, Egr-3, VCAM-1, Ang1 and Tie2. These data suggest that Curculigoside A induces cell proliferation and angiogenesis through the Wnt5a/β-catenin and VEGF/CREB/Egr-3/VCAM-1 signaling axis and promotes maturation and stability of new blood vessels via increasing Ang1 and Tie-2 expression. - Highlights: • Curculigoside A induces cell proliferation through Wnt5a/β-catenin pathway. • Curculigoside A induces angiogenesis via VEGF/CREB/Egr-3/VCAM-1 signaling axis. • Curculigoside A promotes blood vessel maturation via Ang1/Tie2 pathway.

  20. Mechanisms of Hyperhomocysteinemia Induced Skeletal Muscle Myopathy after Ischemia in the CBS−/+ Mouse Model

    Directory of Open Access Journals (Sweden)

    Sudhakar Veeranki

    2015-01-01

    Full Text Available Although hyperhomocysteinemia (HHcy elicits lower than normal body weights and skeletal muscle weakness, the mechanisms remain unclear. Despite the fact that HHcy-mediated enhancement in ROS and consequent damage to regulators of different cellular processes is relatively well established in other organs, the nature of such events is unknown in skeletal muscles. Previously, we reported that HHcy attenuation of PGC-1α and HIF-1α levels enhanced the likelihood of muscle atrophy and declined function after ischemia. In the current study, we examined muscle levels of homocysteine (Hcy metabolizing enzymes, anti-oxidant capacity and focused on protein modifications that might compromise PGC-1α function during ischemic angiogenesis. Although skeletal muscles express the key enzyme (MTHFR that participates in re-methylation of Hcy into methionine, lack of trans-sulfuration enzymes (CBS and CSE make skeletal muscles more susceptible to the HHcy-induced myopathy. Our study indicates that elevated Hcy levels in the CBS−/+ mouse skeletal muscles caused diminished anti-oxidant capacity and contributed to enhanced total protein as well as PGC-1α specific nitrotyrosylation after ischemia. Furthermore, in the presence of NO donor SNP, either homocysteine (Hcy or its cyclized version, Hcy thiolactone, not only increased PGC-1α specific protein nitrotyrosylation but also reduced its association with PPARγ in C2C12 cells. Altogether these results suggest that HHcy exerts its myopathic effects via reduction of the PGC-1/PPARγ axis after ischemia.

  1. Unilateral Renal Ischemia as a Model of Acute Kidney Injury and Renal Fibrosis in Cats.

    Science.gov (United States)

    Schmiedt, C W; Brainard, B M; Hinson, W; Brown, S A; Brown, C A

    2016-01-01

    The objectives of this study were to define the acute and chronic effects of 1-hour unilateral in vivo renal ischemia on renal function and histology in cats. Twenty-one adult purpose-bred research cats were anesthetized, and 1 kidney underwent renal artery and vein occlusion for 1 hour. Serum creatinine and urea concentrations, urine protein:creatinine ratio, urine-specific gravity, glomerular filtration rate, hematocrit, platelet concentration and function, and white blood cell count were measured at baseline and variable time points after ischemia. Renal histopathology was evaluated on days 3, 6, 12, 21, 42, and 70 postischemia; changes in smooth muscle actin and interstitial collagen were examined. Following ischemia, whole animal glomerular filtration rate was significantly reduced (57% of baseline on day 6; P < .05). At the early time points, the ischemic kidneys exhibited severe acute epithelial necrosis accompanied by evidence of regeneration of tubules predominantly within the corticomedullary junction. At later periods, postischemic kidneys had evidence of tubular atrophy and interstitial inflammation with significantly more smooth muscle actin and interstitial collagen staining and interstitial fibrosis when compared with the contralateral control kidneys. This study characterizes the course of ischemic acute kidney injury in cats and demonstrates that ischemic acute kidney injury triggers chronic fibrosis, interstitial inflammation, and tubular atrophy in feline kidneys. These late changes are typical of those observed in cats with naturally occurring chronic kidney disease. © The Author(s) 2015.

  2. Variable Ventilation Improved Respiratory System Mechanics and Ameliorated Pulmonary Damage in a Rat Model of Lung Ischemia-Reperfusion.

    Science.gov (United States)

    Soluri-Martins, André; Moraes, Lillian; Santos, Raquel S; Santos, Cintia L; Huhle, Robert; Capelozzi, Vera L; Pelosi, Paolo; Silva, Pedro L; de Abreu, Marcelo Gama; Rocco, Patricia R M

    2017-01-01

    Lung ischemia-reperfusion injury remains a major complication after lung transplantation. Variable ventilation (VV) has been shown to improve respiratory function and reduce pulmonary histological damage compared to protective volume-controlled ventilation (VCV) in different models of lung injury induced by endotoxin, surfactant depletion by saline lavage, and hydrochloric acid. However, no study has compared the biological impact of VV vs. VCV in lung ischemia-reperfusion injury, which has a complex pathophysiology different from that of other experimental models. Thirty-six animals were randomly assigned to one of two groups: (1) ischemia-reperfusion (IR), in which the left pulmonary hilum was completely occluded and released after 30 min; and (2) Sham, in which animals underwent the same surgical manipulation but without hilar clamping. Immediately after surgery, the left (IR-injured) and right (contralateral) lungs from 6 animals per group were removed, and served as non-ventilated group (NV) for molecular biology analysis. IR and Sham groups were further randomized to one of two ventilation strategies: VCV ( n = 6/group) [tidal volume (V T ) = 6 mL/kg, positive end-expiratory pressure (PEEP) = 2 cmH 2 O, fraction of inspired oxygen (FiO 2 ) = 0.4]; or VV, which was applied on a breath-to-breath basis as a sequence of randomly generated V T values ( n = 1200; mean V T = 6 mL/kg), with a 30% coefficient of variation. After 5 min of ventilation and at the end of a 2-h period (Final), respiratory system mechanics and arterial blood gases were measured. At Final, lungs were removed for histological and molecular biology analyses. Respiratory system elastance and alveolar collapse were lower in VCV than VV (mean ± SD, VCV 3.6 ± 1.3 cmH 2 0/ml and 2.0 ± 0.8 cmH 2 0/ml, p = 0.005; median [interquartile range], VCV 20.4% [7.9-33.1] and VV 5.4% [3.1-8.8], p = 0.04, respectively). In left lungs of IR animals, VCV increased the expression of interleukin-6 and

  3. Variable Ventilation Improved Respiratory System Mechanics and Ameliorated Pulmonary Damage in a Rat Model of Lung Ischemia-Reperfusion

    Directory of Open Access Journals (Sweden)

    Patricia R. M. Rocco

    2017-05-01

    Full Text Available Lung ischemia-reperfusion injury remains a major complication after lung transplantation. Variable ventilation (VV has been shown to improve respiratory function and reduce pulmonary histological damage compared to protective volume-controlled ventilation (VCV in different models of lung injury induced by endotoxin, surfactant depletion by saline lavage, and hydrochloric acid. However, no study has compared the biological impact of VV vs. VCV in lung ischemia-reperfusion injury, which has a complex pathophysiology different from that of other experimental models. Thirty-six animals were randomly assigned to one of two groups: (1 ischemia-reperfusion (IR, in which the left pulmonary hilum was completely occluded and released after 30 min; and (2 Sham, in which animals underwent the same surgical manipulation but without hilar clamping. Immediately after surgery, the left (IR-injured and right (contralateral lungs from 6 animals per group were removed, and served as non-ventilated group (NV for molecular biology analysis. IR and Sham groups were further randomized to one of two ventilation strategies: VCV (n = 6/group [tidal volume (VT = 6 mL/kg, positive end-expiratory pressure (PEEP = 2 cmH2O, fraction of inspired oxygen (FiO2 = 0.4]; or VV, which was applied on a breath-to-breath basis as a sequence of randomly generated VT values (n = 1200; mean VT = 6 mL/kg, with a 30% coefficient of variation. After 5 min of ventilation and at the end of a 2-h period (Final, respiratory system mechanics and arterial blood gases were measured. At Final, lungs were removed for histological and molecular biology analyses. Respiratory system elastance and alveolar collapse were lower in VCV than VV (mean ± SD, VCV 3.6 ± 1.3 cmH20/ml and 2.0 ± 0.8 cmH20/ml, p = 0.005; median [interquartile range], VCV 20.4% [7.9–33.1] and VV 5.4% [3.1–8.8], p = 0.04, respectively. In left lungs of IR animals, VCV increased the expression of interleukin-6 and intercellular

  4. Bayesian Plackett-Luce Mixture Models for Partially Ranked Data.

    Science.gov (United States)

    Mollica, Cristina; Tardella, Luca

    2017-06-01

    The elicitation of an ordinal judgment on multiple alternatives is often required in many psychological and behavioral experiments to investigate preference/choice orientation of a specific population. The Plackett-Luce model is one of the most popular and frequently applied parametric distributions to analyze rankings of a finite set of items. The present work introduces a Bayesian finite mixture of Plackett-Luce models to account for unobserved sample heterogeneity of partially ranked data. We describe an efficient way to incorporate the latent group structure in the data augmentation approach and the derivation of existing maximum likelihood procedures as special instances of the proposed Bayesian method. Inference can be conducted with the combination of the Expectation-Maximization algorithm for maximum a posteriori estimation and the Gibbs sampling iterative procedure. We additionally investigate several Bayesian criteria for selecting the optimal mixture configuration and describe diagnostic tools for assessing the fitness of ranking distributions conditionally and unconditionally on the number of ranked items. The utility of the novel Bayesian parametric Plackett-Luce mixture for characterizing sample heterogeneity is illustrated with several applications to simulated and real preference ranked data. We compare our method with the frequentist approach and a Bayesian nonparametric mixture model both assuming the Plackett-Luce model as a mixture component. Our analysis on real datasets reveals the importance of an accurate diagnostic check for an appropriate in-depth understanding of the heterogenous nature of the partial ranking data.

  5. Acute administration of n-3 rich triglyceride emulsions provides cardioprotection in murine models after ischemia-reperfusion.

    Science.gov (United States)

    Zirpoli, Hylde; Abdillahi, Mariane; Quadri, Nosirudeen; Ananthakrishnan, Radha; Wang, Lingjie; Rosario, Rosa; Zhu, Zhengbin; Deckelbaum, Richard J; Ramasamy, Ravichandran

    2015-01-01

    Dietary n-3 fatty acids (FAs) may reduce cardiovascular disease risk. We questioned whether acute administration of n-3 rich triglyceride (TG) emulsions could preserve cardiac function and decrease injury after ischemia/reperfusion (I/R) insult. We used two different experimental models: in vivo, C57BL/6 mice were exposed to acute occlusion of the left anterior descending coronary artery (LAD), and ex-vivo, C57BL/6 murine hearts were perfused using Langendorff technique (LT). In the LAD model, mice treated with n-3 TG emulsion (1.5 g/kg body weight), immediately after ischemia and 1 h later during reperfusion, significantly reduced infarct size and maintained cardiac function (plevels, as a marker of injury, were significantly reduced by n-3 TG emulsion. To investigate the mechanisms by which n-3 FAs protects hearts from I/R injury, we investigated changes in key pathways linked to cardioprotection. In the ex-vivo model, we showed that n-3 FAs increased phosphorylation of AKT and GSK3β proteins (plevel and reduced an autophagy marker, Beclin-1 (pGSK3β inhibitor plus n-3 TG significantly inhibited LDH release. We conclude that acute n-3 TG injection during reperfusion provides cardioprotection. This may prove to be a novel acute adjunctive reperfusion therapy after treating patients with myocardial infarction.

  6. Microscopy of bacterial translocation during small bowel obstruction and ischemia in vivo – a new animal model

    Directory of Open Access Journals (Sweden)

    Hafner Mathias

    2002-08-01

    Full Text Available Abstract Background Existing animal models provide only indirect information about the pathogenesis of infections caused by indigenous gastrointestinal microflora and the kinetics of bacterial translocation. The aim of this study was to develop a novel animal model to assess bacterial translocation and intestinal barrier function in vivo. Methods In anaesthetized male Wistar rats, 0.5 ml of a suspension of green fluorescent protein-transfected E. coli was administered by intraluminal injection in a model of small bowel obstruction. Animals were randomly subjected to non-ischemic or ischemic bowel obstruction. Ischemia was induced by selective clamping of the terminal mesenteric vessels feeding the obstructed bowel loop. Time intervals necessary for translocation of E. coli into the submucosal stroma and the muscularis propria was assessed using intravital microscopy. Results Bacterial translocation into the submucosa and muscularis propria took a mean of 36 ± 8 min and 80 ± 10 min, respectively, in small bowel obstruction. Intestinal ischemia significantly accelerated bacterial translocation into the submucosa (11 ± 5 min, p E. coli were visible in frozen sections of small bowel, mesentery, liver and spleen taken two hours after E. coli administration. Conclusions Intravital microscopy of fluorescent bacteria is a novel approach to study bacterial translocation in vivo. We have applied this technique to define minimal bacterial transit time as a functional parameter of intestinal barrier function.

  7. Evaluation of adenosine preconditioning with {sup 99m}Tc-His{sub 10}-annexin V in a porcine model of myocardium ischemia and reperfusion injury: preliminary study

    Energy Technology Data Exchange (ETDEWEB)

    Ye Fei [Department of Cardiology, Nanjing First Hospital Affiliated to Nanjing Medical University, 68 Changle Road, Nanjing 210006 (China); Fang Wei [Cardiovascular Institute and Fuwai Hospital, No. 167 Bei-Li-Shi-Lu, Beijing 100037 (China); Wang Feng, E-mail: fengwang1972cn@gmail.co [Department of Nuclear Medicine, Nanjing First Hospital Affiliated to Nanjing Medical University, 68 Changle Road, Nanjing 210006 (China); State Key Laboratory of Pharmaceutical Biotechnology, Department of Biochemistry, College of Life Sciences, Nanjing University, 22 Hankou Road, Nanjing 210093 (China); Hua Zichun [State Key Laboratory of Pharmaceutical Biotechnology, Department of Biochemistry, College of Life Sciences, Nanjing University, 22 Hankou Road, Nanjing 210093 (China); Wang Zizheng [Department of Nuclear Medicine, Nanjing First Hospital Affiliated to Nanjing Medical University, 68 Changle Road, Nanjing 210006 (China); Yang Xiang [State Key Laboratory of Pharmaceutical Biotechnology, Department of Biochemistry, College of Life Sciences, Nanjing University, 22 Hankou Road, Nanjing 210093 (China)

    2011-05-15

    Purpose: The goal of this study was to evaluate the feasibility of {sup 99m}Tc-His{sub 10}-annexin V for the detection of acute myocardial cell death and to assess the effect of adenosine preconditioning in a porcine model of myocardium ischemia and reperfusion injury (RI). Materials and Methods: {sup 99m}Tc-His{sub 10}-annexin V was prepared by one-step direct labeling, and RCP and radiostability were tested. The binding of {sup 99m}Tc-His{sub 10}-annexin V to apoptosis was validated in vitro using camptothecin-induced Jurkat cells. In vivo biodistribution was determined in mice by the dissection method. Ischemia of 20-30 min was induced by balloon occlusion of the epicardial coronary artery of the porcine model (n=14). Adenosine was infused intravenously in six pigs before coronary occlusion. {sup 99m}Tc-His{sub 10}-annexin V (n=12) was injected intravenously at 1 h after reperfusion. SPECT/CT was acquired at 3 h postinjection. Myocardial perfusion imaging (MPI) with {sup 99m}Tc-MIBI was also performed 1 day after His{sub 10}-annexin V imaging. Cardiac tissues were analyzed postmortem using hematoxylin-and-eosin and TUNEL staining. Caspase-3 activity was measured to confirm the presence of apoptosis. Results: {sup 99m}Tc-His{sub 10}-annexin V had a RCP >98% and high stability 2 h after radiolabeling; it could bind to apoptotic cells with high affinity. Biodistribution of {sup 99m}Tc-His{sub 10}-annexin V showed a predominant uptake in the kidney and relatively low uptake in the myocardium, liver and gastrointestinal tract; rapid clearance from blood and kidney was observed. In the untreated group, intense uptake of His{sub 10}-annexin V was visualized in the defect which was shown in MPI, whereas in the adenosine group a mild uptake of {sup 99m}Tc-His{sub 10}-annexin was found in the risk area which showed no defects in the {sup 99m}Tc-MIBI image. TUNEL staining and activated caspase-3 confirmed the ongoing apoptosis in RI. Adenosine preconditioning significantly

  8. Noninvasive Multimodal Imaging to Predict Recovery of Locomotion after Extended Limb Ischemia.

    Directory of Open Access Journals (Sweden)

    Jason S Radowsky

    Full Text Available Acute limb ischemia is a common cause of morbidity and mortality following trauma both in civilian centers and in combat related injuries. Rapid determination of tissue viability and surgical restoration of blood flow are desirable, but not always possible. We sought to characterize the response to increasing periods of hind limb ischemia in a porcine model such that we could define a period of critical ischemia (the point after which irreversible neuromuscular injury occurs, evaluate non-invasive methods for characterizing that ischemia, and establish a model by which we could predict whether or not the animal's locomotion would return to baselines levels post-operatively. Ischemia was induced by either application of a pneumatic tourniquet or vessel occlusion (performed by clamping the proximal iliac artery and vein at the level of the inguinal ligament. The limb was monitored for the duration of the procedure with both 3-charge coupled device (3CCD and infrared (IR imaging for tissue oxygenation and perfusion, respectively. The experimental arms of this model are effective at inducing histologically evident muscle injury with some evidence of expected secondary organ damage, particularly in animals with longer ischemia times. Noninvasive imaging data shows excellent correlation with post-operative functional outcomes, validating its use as a non-invasive means of viability assessment, and directly monitors post-occlusive reactive hyperemia. A classification model, based on partial-least squares discriminant analysis (PLSDA of imaging variables only, successfully classified animals as "returned to normal locomotion" or "did not return to normal locomotion" with 87.5% sensitivity and 66.7% specificity after cross-validation. PLSDA models generated from non-imaging data were not as accurate (AUC of 0.53 compared the PLSDA model generated from only imaging data (AUC of 0.76. With some modification, this limb ischemia model could also serve as a

  9. Modeling of chromosome intermingling by partially overlapping uniform random polygons.

    Science.gov (United States)

    Blackstone, T; Scharein, R; Borgo, B; Varela, R; Diao, Y; Arsuaga, J

    2011-03-01

    During the early phase of the cell cycle the eukaryotic genome is organized into chromosome territories. The geometry of the interface between any two chromosomes remains a matter of debate and may have important functional consequences. The Interchromosomal Network model (introduced by Branco and Pombo) proposes that territories intermingle along their periphery. In order to partially quantify this concept we here investigate the probability that two chromosomes form an unsplittable link. We use the uniform random polygon as a crude model for chromosome territories and we model the interchromosomal network as the common spatial region of two overlapping uniform random polygons. This simple model allows us to derive some rigorous mathematical results as well as to perform computer simulations easily. We find that the probability that one uniform random polygon of length n that partially overlaps a fixed polygon is bounded below by 1 − O(1/√n). We use numerical simulations to estimate the dependence of the linking probability of two uniform random polygons (of lengths n and m, respectively) on the amount of overlapping. The degree of overlapping is parametrized by a parameter [Formula: see text] such that [Formula: see text] indicates no overlapping and [Formula: see text] indicates total overlapping. We propose that this dependence relation may be modeled as f (ε, m, n) = [Formula: see text]. Numerical evidence shows that this model works well when [Formula: see text] is relatively large (ε ≥ 0.5). We then use these results to model the data published by Branco and Pombo and observe that for the amount of overlapping observed experimentally the URPs have a non-zero probability of forming an unsplittable link.

  10. Estimation and variable selection for generalized additive partial linear models

    KAUST Repository

    Wang, Li

    2011-08-01

    We study generalized additive partial linear models, proposing the use of polynomial spline smoothing for estimation of nonparametric functions, and deriving quasi-likelihood based estimators for the linear parameters. We establish asymptotic normality for the estimators of the parametric components. The procedure avoids solving large systems of equations as in kernel-based procedures and thus results in gains in computational simplicity. We further develop a class of variable selection procedures for the linear parameters by employing a nonconcave penalized quasi-likelihood, which is shown to have an asymptotic oracle property. Monte Carlo simulations and an empirical example are presented for illustration. © Institute of Mathematical Statistics, 2011.

  11. Partial differential equation models in the socio-economic sciences.

    Science.gov (United States)

    Burger, Martin; Caffarelli, Luis; Markowich, Peter A

    2014-11-13

    Mathematical models based on partial differential equations (PDEs) have become an integral part of quantitative analysis in most branches of science and engineering, recently expanding also towards biomedicine and socio-economic sciences. The application of PDEs in the latter is a promising field, but widely quite open and leading to a variety of novel mathematical challenges. In this introductory article of the Theme Issue, we will provide an overview of the field and its recent boosting topics. Moreover, we will put the contributions to the Theme Issue in an appropriate perspective. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

  12. Partial differential equation models in the socio-economic sciences

    KAUST Repository

    Burger, Martin

    2014-10-06

    Mathematical models based on partial differential equations (PDEs) have become an integral part of quantitative analysis in most branches of science and engineering, recently expanding also towards biomedicine and socio-economic sciences. The application of PDEs in the latter is a promising field, but widely quite open and leading to a variety of novel mathematical challenges. In this introductory article of the Theme Issue, we will provide an overview of the field and its recent boosting topics. Moreover, we will put the contributions to the Theme Issue in an appropriate perspective.

  13. A Model Fit Statistic for Generalized Partial Credit Model

    Science.gov (United States)

    Liang, Tie; Wells, Craig S.

    2009-01-01

    Investigating the fit of a parametric model is an important part of the measurement process when implementing item response theory (IRT), but research examining it is limited. A general nonparametric approach for detecting model misfit, introduced by J. Douglas and A. S. Cohen (2001), has exhibited promising results for the two-parameter logistic…

  14. [The effect of portal blood stasis on lung and renal injury induced by hepatic ischemia reperfusion in a rabbit model].

    Science.gov (United States)

    Wang, Ye; Yang, Jia-mei; Hou, Yuan-kai; Li, Dian-qi; Hu, Ming-hua; Liu, Peng

    2008-04-15

    To investigate the effect and mechanism of portal blood stasis on lung and renal injury induced by hepatic ischemia reperfusion. A rabbit hepatic ischemia reperfusion injury model was established by hepatic portal occlusion and in situ hypothermic irrigation for 30 min. Twenty-four New Zealand white rabbits were employed and randomly divided into 3 groups equally by different dosage of portal blood stasis removal: group A5 (5 ml blood removal), group A10 (10 ml blood removal),and group B (no blood removal). Eight rabbits were served as controls with no hepatic portal occlusion and hypothermic irrigation. After reperfusion 4 h serum endotoxin content, tumor necrosis factor-alpha (TNF-alpha), urea nitrogen (BUN), and creatinine (Cr) were examined respectively, meantime lung and kidney tissues were sampled to determine the content of malondialdehyde (MDA), superoxide dismutase (SOD), the pathology, and wet to dry weight ratio, broncho-alveolar lavage fluid protein content in lung tissues. Removing portal blood stasis ameliorated lung and renal injury as shown by decreasing the level of serum endotoxin, TNF-alpha, BUN, Cr, wet to dry weight ratio, broncho-alveolar lavage fluid protein content, MDA, SOD. TNF-alpha, Cr, broncho-alveolar lavage fluid protein content in lung tissues and MDA in kidney tissue in group A5 were significantly reduced compared with those in group B (P portal blood stasis before the resume of splanchnic circulation may ameliorate the lung and renal injury induced by hepatic ischemia reperfusion. The possible mechanism may be that portal blood stasis removal reduces endotoxin absorption, and further decreases production of serum TNF-alpha.

  15. Nepeta Dschuparensis Bornm Extract Moderates COX-2 and IL-1β Proteins in a Rat Model of Cerebral Ischemia

    Directory of Open Access Journals (Sweden)

    Alireza Mousavi Nia

    2017-03-01

    Full Text Available Background: Nepeta dschuparensis Bornm (NP is used as a medicinal herb in Iran. In traditional medicine, this herb is extensively employed for curing ailments such as cardiovascular diseases. NP has antioxidant and anti-inflammatory properties. This project examined the effects of the NP extract on cyclooxygenase-2 (COX-2 and interleukin-1β (IL-1β protein levels and its efficacy in neuroprotection in a cerebral ischemia-reperfusion model. Methods: Twenty-six male rats were randomly divided into 3 groups: 1 sham (n=6: no middle cerebral artery occlusion (MCAO procedure, 2 control (n=10: MCAO procedure and treatment with normal saline, and 3 NP extract (n=10: MCAO procedure and treatment with the NP extract (20 mg/kg, i.p. at the beginning of reperfusion. To examine the injury caused by cerebral ischemia, we measured motor coordination and the infarct area using the rotarod test and triphenyl tetrazolium chloride staining, respectively. IL-1β and COX-2 protein levels, as inflammatory markers, were measured by immunoblotting assay. The statistical analyses were performed using SPSS, version 16, and the data are expressed as means±SEMs. Statistical difference was evaluated using the one-way ANOVA, followed by the post hoc LSD test (P<0.01. Results: Treatment with the NP extract significantly diminished the infarct volume and alleviated the motor coordination disorder induced by cerebral ischemia. The NP extract administration significantly attenuated the increase in IL-1β and COX-2 protein levels too (P<0.01. Conclusion: The beneficial effects of the NP extract are related to its ability to decrease the levels of IL-1β and COX-2.

  16. Consistent Partial Least Squares Path Modeling via Regularization.

    Science.gov (United States)

    Jung, Sunho; Park, JaeHong

    2018-01-01

    Partial least squares (PLS) path modeling is a component-based structural equation modeling that has been adopted in social and psychological research due to its data-analytic capability and flexibility. A recent methodological advance is consistent PLS (PLSc), designed to produce consistent estimates of path coefficients in structural models involving common factors. In practice, however, PLSc may frequently encounter multicollinearity in part because it takes a strategy of estimating path coefficients based on consistent correlations among independent latent variables. PLSc has yet no remedy for this multicollinearity problem, which can cause loss of statistical power and accuracy in parameter estimation. Thus, a ridge type of regularization is incorporated into PLSc, creating a new technique called regularized PLSc. A comprehensive simulation study is conducted to evaluate the performance of regularized PLSc as compared to its non-regularized counterpart in terms of power and accuracy. The results show that our regularized PLSc is recommended for use when serious multicollinearity is present.

  17. OUTLIER DETECTION IN PARTIAL ERRORS-IN-VARIABLES MODEL

    Directory of Open Access Journals (Sweden)

    JUN ZHAO

    Full Text Available The weighed total least square (WTLS estimate is very sensitive to the outliers in the partial EIV model. A new procedure for detecting outliers based on the data-snooping is presented in this paper. Firstly, a two-step iterated method of computing the WTLS estimates for the partial EIV model based on the standard LS theory is proposed. Secondly, the corresponding w-test statistics are constructed to detect outliers while the observations and coefficient matrix are contaminated with outliers, and a specific algorithm for detecting outliers is suggested. When the variance factor is unknown, it may be estimated by the least median squares (LMS method. At last, the simulated data and real data about two-dimensional affine transformation are analyzed. The numerical results show that the new test procedure is able to judge that the outliers locate in x component, y component or both components in coordinates while the observations and coefficient matrix are contaminated with outliers

  18. Human Umbilical Cord-Derived Mesenchymal Stromal Cells Improve Left Ventricular Function, Perfusion, and Remodeling in a Porcine Model of Chronic Myocardial Ischemia

    Science.gov (United States)

    Liu, Chuan-Bin; Huang, He; Sun, Ping; Ma, Shi-Ze; Liu, An-Heng; Xue, Jian; Fu, Jin-Hui; Liang, Yu-Qian; Liu, Bing; Wu, Dong-Ying

    2016-01-01

    Stem cell therapy has emerged as a new strategy for treatment of ischemic heart disease. Although umbilical cord-derived mesenchymal stromal cells (UC-MSCs) have been used preferentially in the acute ischemia model, data for the chronic ischemia model are lacking. In this study, we investigated the effect of UC-MSCs originated from Wharton’s jelly in the treatment of chronic myocardial ischemia in a porcine model induced by ameroid constrictor. Four weeks after ameroid constrictor placement, the surviving animals were divided randomly into two groups to undergo saline injection (n = 6) or UC-MSC transplantation (n = 6) through the left main coronary artery. Two additional intravenous administrations of UC-MSCs were performed in the following 2 weeks to enhance therapeutic effect. Cardiac function and perfusion were examined just before and at 4 weeks after intracoronary transplantation. The results showed that pigs with UC-MSC transplantation exhibited significantly greater left ventricular ejection fraction compared with control animals (61.3% ± 1.3% vs. 50.3% ± 2.0%, p UC-MSC treatment improves left ventricular function, perfusion, and remodeling in a porcine model with chronic myocardial ischemia. Significance Ischemic heart disease is the leading cause of death worldwide. Many patients with chronic myocardial ischemia are not suitable for surgery and have no effective drug treatment; they are called “no-option” patients. This study finds that umbilical cord-derived mesenchymal stromal cells transplanted by intracoronary delivery combined with two intravenous administrations was safe and could significantly improve left ventricular function, perfusion, and remodeling in a large-animal model of chronic myocardial ischemia, which provides a new choice for the no-option patients. In addition, this study used clinical-grade mesenchymal stem cells with delivery and assessment methods commonly used clinically to facilitate further clinical transformation. PMID

  19. Neuroactive steroid treatment in the model of focal cerebra ischemia in immature brain

    Czech Academy of Sciences Publication Activity Database

    Valeš, Karel; Uttl, L.; Vondráková, Kateřina; Druga, Rastislav; Kletečková, Lenka; Mikoška, M.; Syslová, K.; Kačer, P.; Stuchlík, Aleš; Vyklický ml., Ladislav; Kudová, Eva; Chodounská, Hana; Tsenov, Grygoriy

    2016-01-01

    Roč. 19, Suppl 1 (2016), s. 22-23 ISSN 1461-1457. [CINP World Congress of Neuropsychopharmacology /30./. 03.07.2016-05.07.2016, Seoul] R&D Projects: GA ČR(CZ) GBP304/12/G069; GA ČR(CZ) GA14-20613S; GA ČR(CZ) GAP303/12/1464; GA TA ČR(CZ) TE01020028 Institutional support: RVO:61388963 ; RVO:67985823 Keywords : neuroactive steroids * focal cerebral ischemia Subject RIV: CC - Organic Chemistry; FH - Neurology (FGU-C)

  20. Optimization Method of Fusing Model Tree into Partial Least Squares

    Directory of Open Access Journals (Sweden)

    Yu Fang

    2017-01-01

    Full Text Available Partial Least Square (PLS can’t adapt to the characteristics of the data of many fields due to its own features multiple independent variables, multi-dependent variables and non-linear. However, Model Tree (MT has a good adaptability to nonlinear function, which is made up of many multiple linear segments. Based on this, a new method combining PLS and MT to analysis and predict the data is proposed, which build MT through the main ingredient and the explanatory variables(the dependent variable extracted from PLS, and extract residual information constantly to build Model Tree until well-pleased accuracy condition is satisfied. Using the data of the maxingshigan decoction of the monarch drug to treat the asthma or cough and two sample sets in the UCI Machine Learning Repository, the experimental results show that, the ability of explanation and predicting get improved in the new method.

  1. Modeling tree crown dynamics with 3D partial differential equations.

    Science.gov (United States)

    Beyer, Robert; Letort, Véronique; Cournède, Paul-Henry

    2014-01-01

    We characterize a tree's spatial foliage distribution by the local leaf area density. Considering this spatially continuous variable allows to describe the spatiotemporal evolution of the tree crown by means of 3D partial differential equations. These offer a framework to rigorously take locally and adaptively acting effects into account, notably the growth toward light. Biomass production through photosynthesis and the allocation to foliage and wood are readily included in this model framework. The system of equations stands out due to its inherent dynamic property of self-organization and spontaneous adaptation, generating complex behavior from even only a few parameters. The density-based approach yields spatially structured tree crowns without relying on detailed geometry. We present the methodological fundamentals of such a modeling approach and discuss further prospects and applications.

  2. An XFEM Model for Hydraulic Fracturing in Partially Saturated Rocks

    Directory of Open Access Journals (Sweden)

    Salimzadeh Saeed

    2016-01-01

    Full Text Available Hydraulic fracturing is a complex multi-physics phenomenon. Numerous analytical and numerical models of hydraulic fracturing processes have been proposed. Analytical solutions commonly are able to model the growth of a single hydraulic fracture into an initially intact, homogeneous rock mass. Numerical models are able to analyse complex problems such as multiple hydraulic fractures and fracturing in heterogeneous media. However, majority of available models are restricted to single-phase flow through fracture and permeable porous rock. This is not compatible with actual field conditions where the injected fluid does not have similar properties as the host fluid. In this study we present a fully coupled hydro-poroelastic model which incorporates two fluids i.e. fracturing fluid and host fluid. Flow through fracture is defined based on lubrication assumption, while flow through matrix is defined as Darcy flow. The fracture discontinuity in the mechanical model is captured using eXtended Finite Element Method (XFEM while the fracture propagation criterion is defined through cohesive fracture model. The discontinuous matrix fluid velocity across fracture is modelled using leak-off loading which couples fracture flow and matrix flow. The proposed model has been discretised using standard Galerkin method, implemented in Matlab and verified against several published solutions. Multiple hydraulic fracturing simulations are performed to show the model robustness and to illustrate how problem parameters such as injection rate and rock permeability affect the hydraulic fracturing variables i.e. injection pressure, fracture aperture and fracture length. The results show the impact of partial saturation on leak-off and the fact that single-phase models may underestimate the leak-off.

  3. Uptake and distribution of a labeled fatty acid in a canine model of ischemia with and without reperfusion

    International Nuclear Information System (INIS)

    Devous, M.D. Sr.

    1985-01-01

    The relationship between regional myocardial blood flow (RMBF) and the regional distribution of 15-(4-iodophenyl)-9-methyl pentadecanoic acid (9-MPDA) was studied in a canine model of myocardial ischemia with and without reperfusion. Group 1 dogs received 135 min of left anterior descending coronary artery (LAD) occlusion; Group 2 dogs received 90 min of LAD occlusion and 45 min of reflow; and Group 3 dogs received 90 min of LAD occlusion and 3.5 hr of reperfusion. All animals received 9-MPDA 15 min prior to sacrifice, and tracer microspheres prior to occlusion, 5 and 80 min after occlusion, 15 min after reperfusion, and 15 min before the end of reperfusion. In Group 1 (permanent ischemia), 9-MPDA distribution was closely correlated with RMBF both 5 and 80 min after occlusion. In Group 2, 9-MPDA uptake was most closely correlated with reperfusion RMBF rather than ischemic RMBF. However, in 1 animal with good reperfusion, 9-MPDA uptake was reduced and was correlated with ischemic blood flow measured 5 min after occlusion. In Group 3, 9-MPDA uptake was correlated with RMBF measured during the ischemic period and not with reperfusion RMBF. It appears that 9-MPDA uptake is determined by RMBF when flow is limited, or early in reperfusion. With prolonged reperfusion, 9-MPDA uptake is significantly reduced in the ischemic zone in the presence of normal flow. This finding implies that the uptake of this fatty acid during reperfusion is related to myocardial damage (myocardial metabolism?) and not to RMBF

  4. Kaempferol Attenuates Myocardial Ischemic Injury via Inhibition of MAPK Signaling Pathway in Experimental Model of Myocardial Ischemia-Reperfusion Injury

    Science.gov (United States)

    Suchal, Kapil; Malik, Salma; Gamad, Nanda; Malhotra, Rajiv Kumar; Goyal, Sameer N.; Chaudhary, Uma; Bhatia, Jagriti; Ojha, Shreesh; Arya, Dharamvir Singh

    2016-01-01

    Kaempferol (KMP), a dietary flavonoid, has antioxidant, anti-inflammatory, and antiapoptotic effects. Hence, we investigated the effect of KMP in ischemia-reperfusion (IR) model of myocardial injury in rats. We studied male albino Wistar rats that were divided into sham, IR-control, KMP-20 + IR, and KMP 20 per se groups. KMP (20 mg/kg; i.p.) was administered daily to rats for the period of 15 days, and, on the 15th day, ischemia was produced by one-stage ligation of left anterior descending coronary artery for 45 min followed by reperfusion for 60 min. After completion of surgery, rats were sacrificed; heart was removed and processed for biochemical, morphological, and molecular studies. KMP pretreatment significantly ameliorated IR injury by maintaining cardiac function, normalizing oxidative stress, and preserving morphological alterations. Furthermore, there was a decrease in the level of inflammatory markers (TNF-α, IL-6, and NFκB), inhibition of active JNK and p38 proteins, and activation of ERK1/ERK2, a prosurvival kinase. Additionally, it also attenuated apoptosis by reducing the expression of proapoptotic proteins (Bax and Caspase-3), TUNEL positive cells, and increased level of antiapoptotic proteins (Bcl-2). In conclusion, KMP protected against IR injury by attenuating inflammation and apoptosis through the modulation of MAPK pathway. PMID:27087891

  5. Kaempferol Attenuates Myocardial Ischemic Injury via Inhibition of MAPK Signaling Pathway in Experimental Model of Myocardial Ischemia-Reperfusion Injury

    Directory of Open Access Journals (Sweden)

    Kapil Suchal

    2016-01-01

    Full Text Available Kaempferol (KMP, a dietary flavonoid, has antioxidant, anti-inflammatory, and antiapoptotic effects. Hence, we investigated the effect of KMP in ischemia-reperfusion (IR model of myocardial injury in rats. We studied male albino Wistar rats that were divided into sham, IR-control, KMP-20 + IR, and KMP 20 per se groups. KMP (20 mg/kg; i.p. was administered daily to rats for the period of 15 days, and, on the 15th day, ischemia was produced by one-stage ligation of left anterior descending coronary artery for 45 min followed by reperfusion for 60 min. After completion of surgery, rats were sacrificed; heart was removed and processed for biochemical, morphological, and molecular studies. KMP pretreatment significantly ameliorated IR injury by maintaining cardiac function, normalizing oxidative stress, and preserving morphological alterations. Furthermore, there was a decrease in the level of inflammatory markers (TNF-α, IL-6, and NFκB, inhibition of active JNK and p38 proteins, and activation of ERK1/ERK2, a prosurvival kinase. Additionally, it also attenuated apoptosis by reducing the expression of proapoptotic proteins (Bax and Caspase-3, TUNEL positive cells, and increased level of antiapoptotic proteins (Bcl-2. In conclusion, KMP protected against IR injury by attenuating inflammation and apoptosis through the modulation of MAPK pathway.

  6. Thrombin effectuates therapeutic arteriogenesis in the rabbit hindlimb ischemia model: A quantitative analysis by computerized in vivo imaging

    International Nuclear Information System (INIS)

    Kagadis, George C.; Karnabatidis, Dimitrios; Katsanos, Konstantinos; Diamantopoulos, Athanassios; Samaras, Nikolaos; Maroulis, John; Siablis, Dimitrios; Nikiforidis, George C.

    2006-01-01

    We report on an experimental mammalian controlled study that documents arteriogenic capacity of thrombin and utilizes computerized algorithms to quantify the newly formed vessels. Hindlimb ischemia was surgically invoked in 10 New Zealand white rabbits. After quiescence of endogenous angiogenesis heterologous bovine thrombin was intramuscularly injected (1500 units) in one hindlimb per rabbit (Group T). Contralateral limbs were infused with normal saline (Group C). Digital subtraction angiography (DSA) of both limbs was performed after thrombin infusion by selective cannulation of the abdominal aorta and digital images were post-processed with computerized algorithms in order to enhance newly formed vessels. Total vessel area and total vessel length were quantified. In vivo functional evaluation included measurements of blood flow volume at the level of the external iliac artery by Doppler ultrasonography both at baseline and at 20 days after thrombin infusion. Total vessel area and length (in pixels) were 14,713+/-1023 and 5466+/-1327 in group T versus 12,015+/-2557 and 4598+/-1269 in group C (p=0.0062 and 0.1526, respectively). Blood flow volumes (ml/min) at baseline and at 20 days after thrombin infusion were 25.87+/-11.09 and 38.06+/-11.72 in group T versus 26.57+/-11.19 and 20.35+/-7.20 in group C (p=0.8898 and 0.0007, respectively). Intramuscular thrombin effectuates an arteriogenic response in the rabbit hindlimb ischemia model. Computerized algorithms may enable accurate quantification of the neovascularization outcome

  7. Niosomes of Ascorbic Acid and α-Tocopherol in the Cerebral Ischemia-Reperfusion Model in Male Rats

    Directory of Open Access Journals (Sweden)

    Jaleh Varshosaz

    2014-01-01

    Full Text Available The objective of the present study was to prepare a stable iv injectable formulation of ascorbic acid and α-tocopherol in preventing the cerebral ischemia. Different niosomal formulations were prepared by Span and Tween mixed with cholesterol. The physicochemical characteristics of niosomal formulations were evaluated in vitro. For in vivo evaluation, the rats were made ischemic by middle cerebral artery occlusion model for 30 min and the selected formulation was used for determining its neuroprotective effect against cerebral ischemia. Neuronal damage was evaluated by optical microscopy and transmission electron microscopy. The encapsulation efficiency of ascorbic acid was increased to more than 84% by remote loading method. The cholesterol content of the niosomes, the hydrophilicity potential of the encapsulated compounds, and the preparation method of niosomes were the main factors affecting the mean volume diameter of the prepared vesicles. High physical stability of the niosomes prepared from Span 40 and Span 60 was demonstrated due to negligible size change of vesicles during 6 months storage at 4–8°C. In vivo studies showed that ST60/Chol 35 : 35 : 30 niosomes had more neuroprotective effects against cerebral ischemic injuries in male rats than free ascorbic acid.

  8. Niosomes of ascorbic acid and α-tocopherol in the cerebral ischemia-reperfusion model in male rats.

    Science.gov (United States)

    Varshosaz, Jaleh; Taymouri, Somayeh; Pardakhty, Abbas; Asadi-Shekaari, Majid; Babaee, Abodolreza

    2014-01-01

    The objective of the present study was to prepare a stable iv injectable formulation of ascorbic acid and α-tocopherol in preventing the cerebral ischemia. Different niosomal formulations were prepared by Span and Tween mixed with cholesterol. The physicochemical characteristics of niosomal formulations were evaluated in vitro. For in vivo evaluation, the rats were made ischemic by middle cerebral artery occlusion model for 30 min and the selected formulation was used for determining its neuroprotective effect against cerebral ischemia. Neuronal damage was evaluated by optical microscopy and transmission electron microscopy. The encapsulation efficiency of ascorbic acid was increased to more than 84% by remote loading method. The cholesterol content of the niosomes, the hydrophilicity potential of the encapsulated compounds, and the preparation method of niosomes were the main factors affecting the mean volume diameter of the prepared vesicles. High physical stability of the niosomes prepared from Span 40 and Span 60 was demonstrated due to negligible size change of vesicles during 6 months storage at 4-8(°)C. In vivo studies showed that ST60/Chol 35 : 35 : 30 niosomes had more neuroprotective effects against cerebral ischemic injuries in male rats than free ascorbic acid.

  9. Curcumin induces therapeutic angiogenesis in a diabetic mouse hindlimb ischemia model via modulating the function of endothelial progenitor cells.

    Science.gov (United States)

    You, Jinzhi; Sun, Jiacheng; Ma, Teng; Yang, Ziying; Wang, Xu; Zhang, Zhiwei; Li, Jingjing; Wang, Longgang; Ii, Masaaki; Yang, Junjie; Shen, Zhenya

    2017-08-03

    Neovascularization is impaired in diabetes mellitus, which leads to the development of peripheral arterial disease and is mainly attributed to the dysfunction of endothelial progenitor cells (EPCs). Previous studies proved the promotional effect of curcumin on neovascularization in wound healing of diabetes. Thus, we hypothesize that curcumin could promote neovascularization at sites of hindlimb ischemia in diabetes and might take effect via modulating the function of EPCs. Streptozotocin-induced type 1 diabetic mice and nondiabetic mice both received unilateral hindlimb ischemic surgery. Curcumin was then administrated to the mice by lavage for 14 days consecutively. Laser Doppler perfusion imaging was conducted to demonstrate the blood flow reperfusion. Capillary density was measured in the ischemic gastrocnemius muscle. In addition, angiogenesis, migration, proliferation abilities, and senescence were determined in EPCs isolated from diabetic and nondiabetic mice. Quantitative PCR was then used to determine the mRNA expression of vascular endothelial growth factor (VEGF) and angiopoetin-1 (Ang-1) in EPCs. Curcumin application to type 1 diabetic mice significantly improved blood reperfusion and increased the capillary density in ischemic hindlimbs. The in-vitro study also revealed that the angiogenesis, migration, and proliferation abilities of EPCs and the number of senescent EPCs were reversed by curcumin application. Quantitative PCR confirmed the overexpression of VEGF-A and Ang-1 in EPCs after curcumin treatment. Curcumin could enhance neovascularization via promoting the function of EPCs in a diabetic mouse hindlimb ischemia model.

  10. The chemical energy unit partial oxidation reactor operation simulation modeling

    Science.gov (United States)

    Mrakin, A. N.; Selivanov, A. A.; Batrakov, P. A.; Sotnikov, D. G.

    2018-01-01

    The chemical energy unit scheme for synthesis gas, electric and heat energy production which is possible to be used both for the chemical industry on-site facilities and under field conditions is represented in the paper. The partial oxidation reactor gasification process mathematical model is described and reaction products composition and temperature determining algorithm flow diagram is shown. The developed software product verification showed good convergence of the experimental values and calculations according to the other programmes: the temperature determining relative discrepancy amounted from 4 to 5 %, while the absolute composition discrepancy ranged from 1 to 3%. The synthesis gas composition was found out practically not to depend on the supplied into the partial oxidation reactor (POR) water vapour enthalpy and compressor air pressure increase ratio. Moreover, air consumption coefficient α increase from 0.7 to 0.9 was found out to decrease synthesis gas target components (carbon and hydrogen oxides) specific yield by nearly 2 times and synthesis gas target components required ratio was revealed to be seen in the water vapour specific consumption area (from 5 to 6 kg/kg of fuel).

  11. Acute administration of n-3 rich triglyceride emulsions provides cardioprotection in murine models after ischemia-reperfusion.

    Directory of Open Access Journals (Sweden)

    Hylde Zirpoli

    Full Text Available Dietary n-3 fatty acids (FAs may reduce cardiovascular disease risk. We questioned whether acute administration of n-3 rich triglyceride (TG emulsions could preserve cardiac function and decrease injury after ischemia/reperfusion (I/R insult. We used two different experimental models: in vivo, C57BL/6 mice were exposed to acute occlusion of the left anterior descending coronary artery (LAD, and ex-vivo, C57BL/6 murine hearts were perfused using Langendorff technique (LT. In the LAD model, mice treated with n-3 TG emulsion (1.5 g/kg body weight, immediately after ischemia and 1 h later during reperfusion, significantly reduced infarct size and maintained cardiac function (p<0.05. In the LT model, administration of n-3 TG emulsion (300 mg TG/100 ml during reperfusion significantly improved functional recovery (p<0.05. In both models, lactate dehydrogenase (LDH levels, as a marker of injury, were significantly reduced by n-3 TG emulsion. To investigate the mechanisms by which n-3 FAs protects hearts from I/R injury, we investigated changes in key pathways linked to cardioprotection. In the ex-vivo model, we showed that n-3 FAs increased phosphorylation of AKT and GSK3β proteins (p<0.05. Acute n-3 TG emulsion treatment also increased Bcl-2 protein level and reduced an autophagy marker, Beclin-1 (p<0.05. Additionally, cardioprotection by n-3 TG emulsion was linked to changes in PPARγ protein expression (p<0.05. Rosiglitazone and p-AKT inhibitor counteracted the positive effect of n-3 TG; GSK3β inhibitor plus n-3 TG significantly inhibited LDH release. We conclude that acute n-3 TG injection during reperfusion provides cardioprotection. This may prove to be a novel acute adjunctive reperfusion therapy after treating patients with myocardial infarction.

  12. A porcine ex vivo lung perfusion model with maximal argon exposure to attenuate ischemia-reperfusion injury

    Directory of Open Access Journals (Sweden)

    An Martens

    2017-01-01

    Full Text Available Argon (Ar is a noble gas with known organoprotective effects in rodents and in vitro models. In a previous study we failed to find a postconditioning effect of Ar during ex vivo lung perfusion (EVLP on warm-ischemic injury in a porcine model. In this study, we further investigated a prolonged exposure to Ar to decrease cold ischemia-reperfusion injury after lung transplantation in a porcine model with EVLP assessment. Domestic pigs (n = 6/group were pre-conditioned for 6 hours with 21% O 2 and 79% N 2 (CONTR or 79% Ar (ARG. Subsequently, lungs were cold flushed and stored inflated on ice for 18 hours inflated with the same gas mixtures. Next, lungs were perfused for 4 hours on EVLP (acellular while ventilated with 12% O 2 and 88% N 2 (CONTR group or 88% Ar (ARG group. The perfusate was saturated with the same gas mixture but with the addition of CO 2 to an end-tidal CO 2 of 35-45 mmHg. The saturated perfusate was drained and lungs were perfused with whole blood for an additional 2 hours on EVLP. Evaluation at the end of EVLP did not show significant effects on physiologic parameters by prolonged exposure to Ar. Also wet-to-dry weight ratio did not improve in the ARG group. Although in other organ systems protective effects of Ar have been shown, we did not detect beneficial effects of a high concentration of Ar on cold pulmonary ischemia-reperfusion injury in a porcine lung model after prolonged exposure to Ar in this porcine model with EVLP assessment.

  13. The effects of deformation, ischemia, and reperfusion on the development of muscle damage during prolonged loading.

    Science.gov (United States)

    Loerakker, S; Manders, E; Strijkers, G J; Nicolay, K; Baaijens, F P T; Bader, D L; Oomens, C W J

    2011-10-01

    Deep tissue injury (DTI) is a severe form of pressure ulcer where tissue damage starts in deep tissues underneath intact skin. In the present study, the contributions of deformation, ischemia, and reperfusion to skeletal muscle damage development were examined in a rat model during a 6-h period. Magnetic resonance imaging (MRI) was used to study perfusion (contrast-enhanced MRI) and tissue integrity (T2-weighted MRI). The levels of tissue deformation were estimated using finite element models. Complete ischemia caused a gradual homogeneous increase in T2 (∼20% during the 6-h period). The effect of reperfusion on T2 was highly variable, depending on the anatomical location. In experiments involving deformation, inevitably associated with partial ischemia, a variable T2 increase (17-66% during the 6-h period) was observed reflecting the significant variation in deformation (with two-dimensional strain energies of 0.60-1.51 J/mm) and ischemia (50.8-99.8% of the leg) between experiments. These results imply that deformation, ischemia, and reperfusion all contribute to the damage process during prolonged loading, although their importance varies with time. The critical deformation threshold and period of ischemia that cause muscle damage will certainly vary between individuals. These variations are related to intrinsic factors, such as pathological state, which partly explain the individual susceptibility to the development of DTI and highlight the need for regular assessments of individual subjects.

  14. Partial differential equations in action from modelling to theory

    CERN Document Server

    Salsa, Sandro

    2016-01-01

    The book is intended as an advanced undergraduate or first-year graduate course for students from various disciplines, including applied mathematics, physics and engineering. It has evolved from courses offered on partial differential equations (PDEs) over the last several years at the Politecnico di Milano. These courses had a twofold purpose: on the one hand, to teach students to appreciate the interplay between theory and modeling in problems arising in the applied sciences, and on the other to provide them with a solid theoretical background in numerical methods, such as finite elements. Accordingly, this textbook is divided into two parts. The first part, chapters 2 to 5, is more elementary in nature and focuses on developing and studying basic problems from the macro-areas of diffusion, propagation and transport, waves and vibrations. In turn the second part, chapters 6 to 11, concentrates on the development of Hilbert spaces methods for the variational formulation and the analysis of (mainly) linear bo...

  15. Risk and Management Control: A Partial Least Square Modelling Approach

    DEFF Research Database (Denmark)

    Nielsen, Steen; Pontoppidan, Iens Christian

    Risk and economic theory goes many year back (e.g. to Keynes & Knight 1921) and risk/uncertainty belong to one of the explanations for the existence of the firm (Coarse, 1937). The present financial crisis going on in the past years have re-accentuated risk and the need of coherence...... and interrelations between risk and areas within management accounting. The idea is that management accounting should be able to conduct a valid feed forward but also predictions for decision making including risk. This study reports the test of a theoretical model using partial least squares (PLS) on survey data...... and a external attitude dimension. The results have important implications for both management control research and for the management control systems design for the way accountants consider the element of risk in their different tasks, both operational and strategic. Specifically, it seems that different risk...

  16. Optimal difference-based estimation for partially linear models

    KAUST Repository

    Zhou, Yuejin; Cheng, Yebin; Dai, Wenlin; Tong, Tiejun

    2017-01-01

    Difference-based methods have attracted increasing attention for analyzing partially linear models in the recent literature. In this paper, we first propose to solve the optimal sequence selection problem in difference-based estimation for the linear component. To achieve the goal, a family of new sequences and a cross-validation method for selecting the adaptive sequence are proposed. We demonstrate that the existing sequences are only extreme cases in the proposed family. Secondly, we propose a new estimator for the residual variance by fitting a linear regression method to some difference-based estimators. Our proposed estimator achieves the asymptotic optimal rate of mean squared error. Simulation studies also demonstrate that our proposed estimator performs better than the existing estimator, especially when the sample size is small and the nonparametric function is rough.

  17. Partial differential equations in action from modelling to theory

    CERN Document Server

    Salsa, Sandro

    2015-01-01

    The book is intended as an advanced undergraduate or first-year graduate course for students from various disciplines, including applied mathematics, physics and engineering. It has evolved from courses offered on partial differential equations (PDEs) over the last several years at the Politecnico di Milano. These courses had a twofold purpose: on the one hand, to teach students to appreciate the interplay between theory and modeling in problems arising in the applied sciences, and on the other to provide them with a solid theoretical background in numerical methods, such as finite elements. Accordingly, this textbook is divided into two parts. The first part, chapters 2 to 5, is more elementary in nature and focuses on developing and studying basic problems from the macro-areas of diffusion, propagation and transport, waves and vibrations. In turn the second part, chapters 6 to 11, concentrates on the development of Hilbert spaces methods for the variational formulation and the analysis of (mainly) linear bo...

  18. Optimal difference-based estimation for partially linear models

    KAUST Repository

    Zhou, Yuejin

    2017-12-16

    Difference-based methods have attracted increasing attention for analyzing partially linear models in the recent literature. In this paper, we first propose to solve the optimal sequence selection problem in difference-based estimation for the linear component. To achieve the goal, a family of new sequences and a cross-validation method for selecting the adaptive sequence are proposed. We demonstrate that the existing sequences are only extreme cases in the proposed family. Secondly, we propose a new estimator for the residual variance by fitting a linear regression method to some difference-based estimators. Our proposed estimator achieves the asymptotic optimal rate of mean squared error. Simulation studies also demonstrate that our proposed estimator performs better than the existing estimator, especially when the sample size is small and the nonparametric function is rough.

  19. PERMINTAAN BERAS DI PROVINSI JAMBI (Penerapan Partial Adjustment Model

    Directory of Open Access Journals (Sweden)

    Wasi Riyanto

    2013-07-01

    Full Text Available The purpose of this study is to determine the effect of price of rice, flour prices, population, income of population and demand of rice for a year earlier on rice demand, demand rice elasticity and rice demand prediction in Jambi Province. This study uses secondary data, including time series data for 22 years from 1988 until 2009. The study used some variables, consist of rice demand (Qdt, the price of rice (Hb, the price of wheat flour (Hg, population (Jp, the income of the population (PDRB and demand for rice the previous year (Qdt-1. The make of this study are multiple regression and dynamic analysis a Partial Adjustment Model, where the demand for rice is the dependent variable and the price of rice, flour prices, population, income population and demand of rice last year was the independent variable. Partial Adjustment Model analysis results showed that the effect of changes in prices of rice and flour are not significant to changes in demand for rice. The population and demand of rice the previous year has positive and significant impact on demand for rice, while revenues have negative and significant population of rice demand. Variable price of rice, earning population and the price of flour is inelastic the demand of rice, because rice is not a normal good but as a necessity so that there is no substitution of goods (replacement of rice with other commodities in Jambi Province. Based on the analysis, it is recommended to the government to be able to control the rate of population increase given the variable number of people as one of the factors that affect demand for rice.It is expected that the government also began to socialize in a lifestyle of non-rice food consumption to control the increasing amount of demand for rice. Last suggestion, the government developed a diversification of staple foods other than rice.

  20. Consistent Partial Least Squares Path Modeling via Regularization

    Directory of Open Access Journals (Sweden)

    Sunho Jung

    2018-02-01

    Full Text Available Partial least squares (PLS path modeling is a component-based structural equation modeling that has been adopted in social and psychological research due to its data-analytic capability and flexibility. A recent methodological advance is consistent PLS (PLSc, designed to produce consistent estimates of path coefficients in structural models involving common factors. In practice, however, PLSc may frequently encounter multicollinearity in part because it takes a strategy of estimating path coefficients based on consistent correlations among independent latent variables. PLSc has yet no remedy for this multicollinearity problem, which can cause loss of statistical power and accuracy in parameter estimation. Thus, a ridge type of regularization is incorporated into PLSc, creating a new technique called regularized PLSc. A comprehensive simulation study is conducted to evaluate the performance of regularized PLSc as compared to its non-regularized counterpart in terms of power and accuracy. The results show that our regularized PLSc is recommended for use when serious multicollinearity is present.

  1. Testing Danegaptide Effects on Kidney Function after Ischemia/Reperfusion Injury in a New Porcine Two Week Model.

    Directory of Open Access Journals (Sweden)

    Chris Amdisen

    Full Text Available Ischemia/reperfusion injury (I/R-I is a leading cause of acute kidney injury (AKI and is associated with increased mortality. Danegaptide is a selective modifier of the gap junction protein connexion 43. It has cytoprotective as well as anti-arrhythmic properties and has been shown to reduce the size of myocardial infarct in pigs. The aim of this study was to investigate the ischemia-protective effect of Danegaptide in a porcine renal I/R-I model with two weeks follow up.Unilateral renal I/R-I was induced in pigs by clamping the left renal artery over a two hour period. The model allowed examination of renal blood flow by magnetic resonance imaging (MRI and the measurement of single kidney GFR two weeks after injury. Eleven animals were randomized to Danegaptide-infusion while nine animals received placebo. Kidney histology and urinary neutrophil gelatinase-associated lipocalin (NGAL excretion were included as markers of AKI.Unilateral kidney I/R-I resulted in an immediate ~50% GFR reduction, associated with a four-fold increase in urinary NGAL-excretion. Fourteen days after I/R-I, the total GFR was ~75% of baseline with a significantly lower GFR in the injured left kidney compared to the right kidney. No differences in GFR were observed between the treated and non-treated animals immediately after I/R-I or at Day 14. Furthermore, no differences were observed in the urinary excretion of NGAL, renal blood flow or other markers of renal function.As expected this porcine renal I/R-I model was associated with reduced GFR two weeks after injury. Danegaptide did not improve renal function after I/R-I.

  2. Astrocytic gap junctional networks suppress cellular damage in an in vitro model of ischemia

    Energy Technology Data Exchange (ETDEWEB)

    Shinotsuka, Takanori; Yasui, Masato; Nuriya, Mutsuo, E-mail: mnuriya@z2.keio.jp

    2014-02-07

    Highlights: • Astrocytes exhibit characteristic changes in [Ca{sup 2+}]{sub i} under OGD. • Astrocytic [Ca{sup 2+}]{sub i} increase is synchronized with a neuronal anoxic depolarization. • Gap junctional couplings protect neurons as well as astrocytes during OGD. - Abstract: Astrocytes play pivotal roles in both the physiology and the pathophysiology of the brain. They communicate with each other via extracellular messengers as well as through gap junctions, which may exacerbate or protect against pathological processes in the brain. However, their roles during the acute phase of ischemia and the underlying cellular mechanisms remain largely unknown. To address this issue, we imaged changes in the intracellular calcium concentration ([Ca{sup 2+}]{sub i}) in astrocytes in mouse cortical slices under oxygen/glucose deprivation (OGD) condition using two-photon microscopy. Under OGD, astrocytes showed [Ca{sup 2+}]{sub i} oscillations followed by larger and sustained [Ca{sup 2+}]{sub i} increases. While the pharmacological blockades of astrocytic receptors for glutamate and ATP had no effect, the inhibitions of gap junctional intercellular coupling between astrocytes significantly advanced the onset of the sustained [Ca{sup 2+}]{sub i} increase after OGD exposure. Interestingly, the simultaneous recording of the neuronal membrane potential revealed that the onset of the sustained [Ca{sup 2+}]{sub i} increase in astrocytes was synchronized with the appearance of neuronal anoxic depolarization. Furthermore, the blockade of gap junctional coupling resulted in a concurrent faster appearance of neuronal depolarizations, which remain synchronized with the sustained [Ca{sup 2+}]{sub i} increase in astrocytes. These results indicate that astrocytes delay the appearance of the pathological responses of astrocytes and neurons through their gap junction-mediated intercellular network under OGD. Thus, astrocytic gap junctional networks provide protection against tissue damage

  3. Astrocytic gap junctional networks suppress cellular damage in an in vitro model of ischemia

    International Nuclear Information System (INIS)

    Shinotsuka, Takanori; Yasui, Masato; Nuriya, Mutsuo

    2014-01-01

    Highlights: • Astrocytes exhibit characteristic changes in [Ca 2+ ] i under OGD. • Astrocytic [Ca 2+ ] i increase is synchronized with a neuronal anoxic depolarization. • Gap junctional couplings protect neurons as well as astrocytes during OGD. - Abstract: Astrocytes play pivotal roles in both the physiology and the pathophysiology of the brain. They communicate with each other via extracellular messengers as well as through gap junctions, which may exacerbate or protect against pathological processes in the brain. However, their roles during the acute phase of ischemia and the underlying cellular mechanisms remain largely unknown. To address this issue, we imaged changes in the intracellular calcium concentration ([Ca 2+ ] i ) in astrocytes in mouse cortical slices under oxygen/glucose deprivation (OGD) condition using two-photon microscopy. Under OGD, astrocytes showed [Ca 2+ ] i oscillations followed by larger and sustained [Ca 2+ ] i increases. While the pharmacological blockades of astrocytic receptors for glutamate and ATP had no effect, the inhibitions of gap junctional intercellular coupling between astrocytes significantly advanced the onset of the sustained [Ca 2+ ] i increase after OGD exposure. Interestingly, the simultaneous recording of the neuronal membrane potential revealed that the onset of the sustained [Ca 2+ ] i increase in astrocytes was synchronized with the appearance of neuronal anoxic depolarization. Furthermore, the blockade of gap junctional coupling resulted in a concurrent faster appearance of neuronal depolarizations, which remain synchronized with the sustained [Ca 2+ ] i increase in astrocytes. These results indicate that astrocytes delay the appearance of the pathological responses of astrocytes and neurons through their gap junction-mediated intercellular network under OGD. Thus, astrocytic gap junctional networks provide protection against tissue damage during the acute phase of ischemia

  4. Modeling of termokinetic oscillations at partial oxidation of methane

    Science.gov (United States)

    Arutyunov, A. V.; Belyaev, A. A.; Inovenkov, I. N.; Nefedov, V. V.

    2017-12-01

    Partial oxidation of natural gas at moderate temperatures below 1500 K has significant interest for a number of industrial applications. But such processes can proceed at different unstable regimes including oscillating modes. Nonlinear phenomena at partial oxidation of methane were observed at different conditions. The investigation of the complex nonlinear system of equations that describes this process is a real method to insure its stability at industrial conditions and, at the same time, is an effective tool for its further enhancement. Numerical analysis of methane oxidation kinetics in the continuous stirred-tank reactor, with the use of detailed kinetic model has shown the possibility of the appearance of oscillating modes in the appropriate range of reaction parameters that characterize the composition, pressure, reagents flow, thermophysical features of the system, and geometry of the reactor. The appearance of oscillating modes is connected both with the reaction kinetics, heat release and sink and reagents introduction and removing. At that, oscillations appear only at a limited range of parameters, but can be accompanied by significant change in the yield of products. We have determined the range of initial temperature and pressure at which oscillations can be observed, if all other parameters remained fixed. The boundaries of existence of oscillations on the phase plane were calculated. It was shown that depending on the position inside the oscillation region the oscillations have different frequency and amplitude. It was reviled the role of heat exchange with the environment: at the absence of heat exchange the oscillating modes are impossible. In the vicinity of the boundary of phase range, where oscillations exist, significant change of concentration of some products were observed, for example, that of CO2, which in this case one of the principal products is. At that, insignificant increase in pressure not only change the character of CO2 behaving

  5. Surgical treatment of cerebral ischemia by means of diode laser: first experimental results and comparison with theoretical model

    Science.gov (United States)

    Signorelli, C. D.; Giaquinta, A.; Iofrida, G.; Donato, G.; Signorelli, Fr.; Bellecci, C.; Lo Feudo, T.; Gaudio, P.; Gelfusa, M.

    2007-07-01

    In the present paper feasibility and potential advantages of using diode laser for surgical treatment of cerebral ischemia and intracranial aneurysms will be evaluated. At this purpose non linear mathematical model was developed and experimentally validated to investigate the effects of the changes in tissue physical properties, in terms of operating time, tensile strength and tissue damage during medical laser application. The numerical simulations have been carried on by a finite-elements based software package (FEMLAB). In vitro results of human saphenous veins of inferior limbs (n=55) after 799 nm diode laser soldering, combined with an indocyanine green-enhanced, will be presented. The simulations results and their comparison with experimental measurements will be reported.

  6. Intracoronary infusion of Wharton’ jelly derived mesenchymal stem cells in the treatment of chronic ischemia cardiomyopathy in porcine model

    Directory of Open Access Journals (Sweden)

    Ning-kun ZHANG

    2015-11-01

    Full Text Available Objective To investigate the safety and efficacy of transplantation of allogeneic Wharton' jelly-derived mesenchymal stem cells (WJMSCs in a porcine model of chronic ischemia cardiomyopathy. Methods Cardiomyopathy models (CIMP were reproduced in 25 minipigs out of 29 by left anterior descending coronary artery balloon occlusion, and the 4 remains served as sham group. The left ventricular ejection fraction (LVEF was detected by echocardiography, and the value ≤45% was defined as successful modeling. Of that 25 minipigs, 5 died, 3 failed of modeling and 17 remains were successfully modelled. The dose safety experiment of WJMSCs transplantation was firstly performed in 3 successful models and 3 failed models. Three doses were teste d in turn at 6×106, 1×107 and 2×107 with 1 successful and 1 failed model for each dose, and TIMI 3 was considered safety dosage. The remainder 14 CIMP models were randomly assigned to transplantation group and control group (7 each, and given 2×107 WJMSCs intracoronary infusion or equal amounts of normal saline respectively. Echocardiography, histopathology and immunofluorescence tests were performed 8 weeks after WJMSCs transplantation. Results LVEF increased by 11.6% (P<0.01 and the left ventricular end systolic volume decreased by 4.1ml (P<0.05 in CIMP models 8 weeks after WJMSCs transplantation, while in control group the ventricular function further deteriorated (LVEF decreased from 42.8% to 35.9%, P<0.01 and the left ventricular further expanded [left ventricular end diastolic volume (LVEDV increased from 42.8±1.2ml to 46.7±1.3ml (P<0.05]. Histopathological assessment showed that the ventricular wall in the infarction area was significantly thickening and the vascular density in the border zone was obviously increased in transplantation group. Immunofluorescence test revealed that the injected Myc-WJMSCs survived in the immunocompetent host heart, and colocalized with cardiac troponin T, α-actin and

  7. Groundwater flow modelling of an abandoned partially open repository

    Energy Technology Data Exchange (ETDEWEB)

    Bockgaard, Niclas (Golder Associates AB (Sweden))

    2010-12-15

    As a part of the license application, according to the nuclear activities act, for a final repository for spent nuclear fuel at Forsmark, the Swedish Nuclear Fuel and Waste Management Company (SKB) has undertaken a series of groundwater flow modelling studies. These represent time periods with different hydraulic conditions and the simulations carried out contribute to the overall evaluation of the repository design and long-term radiological safety. The modelling study presented here serves as an input for analyses of so-called future human actions that may affect the repository. The objective of the work was to investigate the hydraulic influence of an abandoned partially open repository. The intention was to illustrate a pessimistic scenario of the effect of open tunnels in comparison to the reference closure of the repository. The effects of open tunnels were studied for two situations with different boundary conditions: A 'temperate' case with present-day boundary conditions and a generic future 'glacial' case with an ice sheet covering the repository. The results were summarized in the form of analyses of flow in and out from open tunnels, the effect on hydraulic head and flow in the surrounding rock volume, and transport performance measures of flow paths from the repository to surface

  8. Groundwater flow modelling of an abandoned partially open repository

    International Nuclear Information System (INIS)

    Bockgaard, Niclas

    2010-12-01

    As a part of the license application, according to the nuclear activities act, for a final repository for spent nuclear fuel at Forsmark, the Swedish Nuclear Fuel and Waste Management Company (SKB) has undertaken a series of groundwater flow modelling studies. These represent time periods with different hydraulic conditions and the simulations carried out contribute to the overall evaluation of the repository design and long-term radiological safety. The modelling study presented here serves as an input for analyses of so-called future human actions that may affect the repository. The objective of the work was to investigate the hydraulic influence of an abandoned partially open repository. The intention was to illustrate a pessimistic scenario of the effect of open tunnels in comparison to the reference closure of the repository. The effects of open tunnels were studied for two situations with different boundary conditions: A 'temperate' case with present-day boundary conditions and a generic future 'glacial' case with an ice sheet covering the repository. The results were summarized in the form of analyses of flow in and out from open tunnels, the effect on hydraulic head and flow in the surrounding rock volume, and transport performance measures of flow paths from the repository to surface

  9. Application of Stochastic Partial Differential Equations to Reservoir Property Modelling

    KAUST Repository

    Potsepaev, R.

    2010-09-06

    Existing algorithms of geostatistics for stochastic modelling of reservoir parameters require a mapping (the \\'uvt-transform\\') into the parametric space and reconstruction of a stratigraphic co-ordinate system. The parametric space can be considered to represent a pre-deformed and pre-faulted depositional environment. Existing approximations of this mapping in many cases cause significant distortions to the correlation distances. In this work we propose a coordinate free approach for modelling stochastic textures through the application of stochastic partial differential equations. By avoiding the construction of a uvt-transform and stratigraphic coordinates, one can generate realizations directly in the physical space in the presence of deformations and faults. In particular the solution of the modified Helmholtz equation driven by Gaussian white noise is a zero mean Gaussian stationary random field with exponential correlation function (in 3-D). This equation can be used to generate realizations in parametric space. In order to sample in physical space we introduce a stochastic elliptic PDE with tensor coefficients, where the tensor is related to correlation anisotropy and its variation is physical space.

  10. Is Chronic Curcumin Supplementation Neuroprotective Against Ischemia for Antioxidant Activity, Neurological Deficit, or Neuronal Apoptosis in an Experimental Stroke Model?

    Science.gov (United States)

    Altinay, Serdar; Cabalar, Murat; Isler, Cihan; Yildirim, Funda; Celik, Duygu S; Zengi, Oguzhan; Tas, Abdurrahim; Gulcubuk, Ahmet

    2017-01-01

    To investigate the neuroprotective effect of chronic curcumin supplementation on the rat forebrain prior to ischemia and reperfusion. Forebrain ischemia was induced by bilateral common carotid artery occlusion for 1/2 hour, followed by reperfusion for 72 hours. Older rats were divided into five groups: Group I received 300 mg/kg oral curcumin for 21 days before ischemia and 300 mg/kg intraperitoneal curcumin after ischemia; Group II received 300 mg/kg intraperitoneal curcumin after ischemia; Group III received 300 mg/kg oral curcumin for 21 days before ischemia; Group IV had only ischemia; Group V was the sham-operated group. The forebrain was rapidly dissected for biochemical parameter assessment and histopathological examination. In forebrain tissue, enzyme activities of superoxide dismutase, glutathione peroxidase, and catalase were significantly higher in Group I than Groups II or III (p curcumin-treated groups compared with the ischemic group. We also found a marked reduction in apoptotic index after 72 hours in the groups receiving curcumin. Significantly more TUNEL-positive cells were observed in the ischemic group compared to those treated with curcumin. We demonstrated the neuroprotective effect of chronic curcumin supplement on biochemical parameters, neurological scores and apoptosis following ischemia and reperfusion injury in rats.

  11. Permintaan Beras di Provinsi Jambi (Penerapan Partial Adjustment Model

    Directory of Open Access Journals (Sweden)

    Wasi Riyanto

    2013-07-01

    Full Text Available The purpose of this study is to determine the effect of price of rice, flour prices, population, income of population and demand of rice for a year earlier on rice demand, demand rice elasticity and rice demand prediction in Jambi Province. This study uses secondary data, including time series data for 22 years from 1988 until 2009. The study used some variables, consist of rice demand (Qdt, the price of rice (Hb, the price of wheat flour (Hg, population (Jp, the income of the population (PDRB and demand for rice the previous year (Qdt-1. The make of this study are multiple regression and dynamic analysis  a Partial Adjustment Model, where the demand for rice is the dependent variable and the price of rice, flour prices, population, income population and demand of rice last year was the independent variable. Partial Adjustment Model analysis results showed that the effect of changes in prices of rice  and flour are not significant  to  changes in demand for rice. The population and demand of rice the previous year has positive and significant impact on demand for rice, while revenues have negative and significant population of rice demand. Variable price of rice, earning population and the price of flour is inelastic the demand of rice, because rice is not a normal good but as a necessity so that there is no substitution of goods (replacement of rice with other commodities in Jambi Province. Based on the analysis, it is recommended to the government to be able to control the rate of population increase given the variable number of people as one of the factors that affect demand for rice.It is expected that the  government also began  to  socialize  in a lifestyle  of  non-rice food consumption to control the increasing amount of demand for rice. Last suggestion, the government developed a diversification of staple foods other than rice. Keywords: Demand, Rice, Income Population

  12. Erythropoietin inhibits HIF-1α expression via upregulation of PHD-2 transcription and translation in an in-vitro model of hypoxia ischemia

    Science.gov (United States)

    Souvenir, Rhonda; Flores, Jerry J.; Ostrowski, Robert P.; Manaenko, Anatol; Duris, Kamil; Tang, Jiping

    2014-01-01

    Hypoxia inducible factor (HIF)-1α is the central transcriptional factor for the regulation of oxygen-associated genes in response to hypoxia. Erythropoietin (EPO), a hematopoietic growth factor, increases oxygen availability during hypoxia/ischemia and is associated with neuroprotection following hypoxia ischemia in laboratory models of stroke. However, EPO has failed to translate in a clinical setting. Thus it is critical to elucidate the key players in EPO-induced neuroprotection. Our preliminary studies have shown that EPO, as a downstream gene of hypoxia inducible factor (HIF), inhibits HIF-1α in a dose-dependent manner in an in-vitro model of hypoxia ischemia. This study is designed to elucidate the primary mediator of EPO-induced HIF-1α inhibition and subsequent cell survival/neuroprotection. Oxygen and glucose deprivation (OGD) of nerve growth factor (NGF) differentiated rat pheochromocytoma (PC-12) cells were used to model hypoxia ischemia in an in vitro environment. The profile of HIF-1α, HIF-2α and PHD-2 expression, HIF-1α and prolyl hydroxylase (PHD-2) mRNA levels, MMP-9 and cell death was evaluated in the presence and absence of either EPO or PHD-2 inhibitor during OGD. Our findings showed that EPO treatment resulted in an increase in PHD-2 transcription and translation, inhibition of HIF-1α expression, reactive oxygen species (ROS) formation and matrix metalloproteinase (MMP)-9 activity, resulting in increased cell survival after OGD. We also observed that EPO-induced cell survival/neuroprotection was reversed by siRNA silencing of PHD-2. This led to the conclusion that PHD-2 is a key mediator of EPO-induced HIF-1α inhibition and subsequent neuroprotection in an in vitro model of hypoxia ischemia. PMID:24323731

  13. Erythropoietin inhibits HIF-1α expression via upregulation of PHD-2 transcription and translation in an in vitro model of hypoxia-ischemia.

    Science.gov (United States)

    Souvenir, Rhonda; Flores, Jerry J; Ostrowski, Robert P; Manaenko, Anatol; Duris, Kamil; Tang, Jiping

    2014-02-01

    Hypoxia inducible factor (HIF)-1α is the central transcriptional factor for the regulation of oxygen-associated genes in response to hypoxia. Erythropoietin (EPO), a hematopoietic growth factor, increases oxygen availability during hypoxia/ischemia and is associated with neuroprotection following hypoxia-ischemia in laboratory models of stroke. However, EPO has failed to translate in a clinical setting. Thus, it is critical to elucidate the key players in EPO-induced neuroprotection. Our preliminary studies have shown that EPO, as a downstream gene of HIF, inhibits HIF-1α in a dose-dependent manner in an in vitro model of hypoxia-ischemia. This study is designed to elucidate the primary mediator of EPO-induced HIF-1α inhibition and subsequent cell survival/neuroprotection. Oxygen and glucose deprivation (OGD) of nerve growth factor-differentiated rat pheochromocytoma (PC-12) cells were used to model hypoxia-ischemia in an in vitro environment. The profile of HIF-1α, HIF-2α and prolyl hydroxylase domain 2 (PHD-2) expression; HIF-1α and prolyl hydroxylase (PHD-2) mRNA levels; matrix metalloproteinase (MMP)-9; and cell death was evaluated in the presence and absence of either EPO or PHD-2 inhibitor during OGD. Our findings showed that EPO treatment resulted in an increase in PHD-2 transcription and translation, inhibition of HIF-1α expression, reactive oxygen species formation, and MMP-9 activity, resulting in increased cell survival after OGD. We also observed that EPO-induced cell survival/neuroprotection was reversed by siRNA silencing of PHD-2. This led to the conclusion that PHD-2 is a key mediator of EPO-induced HIF-1α inhibition and subsequent neuroprotection in an in vitro model of hypoxia-ischemia.

  14. Magnetic resonance spectroscopy and imaging in cerebral ischemia

    International Nuclear Information System (INIS)

    Rijen, P.C. van.

    1991-01-01

    In-vivo proton and phosphorus magnetic resonance spectroscopy was used to detect changes in cerebral metabolism during ischemia and other types of metabolic stress. Magnetic resonance imaging was performed in an animal model to observe morphological alterations during focal cerebral ischemia. Spectroscopy was performed in animal models with global ischemia, in volunteers during hyperventilation and pharmaco-logically altered cerebral perfusion, and in patients with acute and prolonged focal cerebral ischemia. (author). 396 refs.; 44 figs.; 14 tabs

  15. Treatment with the C5a receptor antagonist ADC-1004 reduces myocardial infarction in a porcine ischemia-reperfusion model

    Directory of Open Access Journals (Sweden)

    Arheden Håkan

    2010-09-01

    Full Text Available Abstract Background Polymorphonuclear neutrophils, stimulated by the activated complement factor C5a, have been implicated in cardiac ischemia/reperfusion injury. ADC-1004 is a competitive C5a receptor antagonist that has been shown to inhibit complement related neutrophil activation. ADC-1004 shields the neutrophils from C5a activation before they enter the reperfused area, which could be a mechanistic advantage compared to previous C5a directed reperfusion therapies. We investigated if treatment with ADC-1004, according to a clinically applicable protocol, would reduce infarct size and microvascular obstruction in a large animal myocardial infarct model. Methods In anesthetized pigs (42-53 kg, a percutaneous coronary intervention balloon was inflated in the left anterior descending artery for 40 minutes, followed by 4 hours of reperfusion. Twenty minutes after balloon inflation the pigs were randomized to an intravenous bolus administration of ADC-1004 (175 mg, n = 8 or saline (9 mg/ml, n = 8. Area at risk (AAR was evaluated by ex vivo SPECT. Infarct size and microvascular obstruction were evaluated by ex vivo MRI. The observers were blinded to the treatment at randomization and analysis. Results ADC-1004 treatment reduced infarct size by 21% (ADC-1004: 58.3 ± 3.4 vs control: 74.1 ± 2.9%AAR, p = 0.007. Microvascular obstruction was similar between the groups (ADC-1004: 2.2 ± 1.2 vs control: 5.3 ± 2.5%AAR, p = 0.23. The mean plasma concentration of ADC-1004 was 83 ± 8 nM at sacrifice. There were no significant differences between the groups with respect to heart rate, mean arterial pressure, cardiac output and blood-gas data. Conclusions ADC-1004 treatment reduces myocardial ischemia-reperfusion injury and represents a novel treatment strategy of myocardial infarct with potential clinical applicability.

  16. Dll4-Notch signaling determines the formation of native arterial collateral networks and arterial function in mouse ischemia models.

    Science.gov (United States)

    Cristofaro, Brunella; Shi, Yu; Faria, Marcella; Suchting, Steven; Leroyer, Aurelie S; Trindade, Alexandre; Duarte, Antonio; Zovein, Ann C; Iruela-Arispe, M Luisa; Nih, Lina R; Kubis, Nathalie; Henrion, Daniel; Loufrani, Laurent; Todiras, Mihail; Schleifenbaum, Johanna; Gollasch, Maik; Zhuang, Zhen W; Simons, Michael; Eichmann, Anne; le Noble, Ferdinand

    2013-04-01

    Arteriogenesis requires growth of pre-existing arteriolar collateral networks and determines clinical outcome in arterial occlusive diseases. Factors responsible for the development of arteriolar collateral networks are poorly understood. The Notch ligand Delta-like 4 (Dll4) promotes arterial differentiation and restricts vessel branching. We hypothesized that Dll4 may act as a genetic determinant of collateral arterial networks and functional recovery in stroke and hind limb ischemia models in mice. Genetic loss- and gain-of-function approaches in mice showed that Dll4-Notch signaling restricts pial collateral artery formation by modulating arterial branching morphogenesis during embryogenesis. Adult Dll4(+/-) mice showed increased pial collateral numbers, but stroke volume upon middle cerebral artery occlusion was not reduced compared with wild-type littermates. Likewise, Dll4(+/-) mice showed reduced blood flow conductance after femoral artery occlusion, and, despite markedly increased angiogenesis, tissue ischemia was more severe. In peripheral arteries, loss of Dll4 adversely affected excitation-contraction coupling in arterial smooth muscle in response to vasopressor agents and arterial vessel wall adaption in response to increases in blood flow, collectively contributing to reduced flow reserve. We conclude that Dll4-Notch signaling modulates native collateral formation by acting on vascular branching morphogenesis during embryogenesis. Dll4 furthermore affects tissue perfusion by acting on arterial function and structure. Loss of Dll4 stimulates collateral formation and angiogenesis, but in the context of ischemic diseases such beneficial effects are overruled by adverse functional changes, demonstrating that ischemic recovery is not solely determined by collateral number but rather by vessel functionality.

  17. Dll4-Notch signaling determines the formation of native arterial collateral networks and arterial function in mouse ischemia models

    Science.gov (United States)

    Cristofaro, Brunella; Shi, Yu; Faria, Marcella; Suchting, Steven; Leroyer, Aurelie S.; Trindade, Alexandre; Duarte, Antonio; Zovein, Ann C.; Iruela-Arispe, M. Luisa; Nih, Lina R.; Kubis, Nathalie; Henrion, Daniel; Loufrani, Laurent; Todiras, Mihail; Schleifenbaum, Johanna; Gollasch, Maik; Zhuang, Zhen W.; Simons, Michael; Eichmann, Anne; le Noble, Ferdinand

    2013-01-01

    Arteriogenesis requires growth of pre-existing arteriolar collateral networks and determines clinical outcome in arterial occlusive diseases. Factors responsible for the development of arteriolar collateral networks are poorly understood. The Notch ligand Delta-like 4 (Dll4) promotes arterial differentiation and restricts vessel branching. We hypothesized that Dll4 may act as a genetic determinant of collateral arterial networks and functional recovery in stroke and hind limb ischemia models in mice. Genetic loss- and gain-of-function approaches in mice showed that Dll4-Notch signaling restricts pial collateral artery formation by modulating arterial branching morphogenesis during embryogenesis. Adult Dll4+/- mice showed increased pial collateral numbers, but stroke volume upon middle cerebral artery occlusion was not reduced compared with wild-type littermates. Likewise, Dll4+/- mice showed reduced blood flow conductance after femoral artery occlusion, and, despite markedly increased angiogenesis, tissue ischemia was more severe. In peripheral arteries, loss of Dll4 adversely affected excitation-contraction coupling in arterial smooth muscle in response to vasopressor agents and arterial vessel wall adaption in response to increases in blood flow, collectively contributing to reduced flow reserve. We conclude that Dll4-Notch signaling modulates native collateral formation by acting on vascular branching morphogenesis during embryogenesis. Dll4 furthermore affects tissue perfusion by acting on arterial function and structure. Loss of Dll4 stimulates collateral formation and angiogenesis, but in the context of ischemic diseases such beneficial effects are overruled by adverse functional changes, demonstrating that ischemic recovery is not solely determined by collateral number but rather by vessel functionality. PMID:23533173

  18. Microstrip natural wave spectrum mathematical model using partial inversion method

    International Nuclear Information System (INIS)

    Pogarsky, S.A.; Litvinenko, L.N.; Prosvirnin, S.L.

    1995-01-01

    It is generally agreed that both microstrip lines itself and different discontinuities based on microstrips are the most difficult problem for accurate electrodynamic analysis. Over the last years much has been published about principles and accurate (or full wave) methods of microstrip lines investigations. The growing interest for this problem may be explained by the microstrip application in the millimeter-wave range for purpose of realizing interconnects and a variety of passive components. At these higher operating rating frequencies accurate component modeling becomes more critical. A creation, examination and experimental verification of the accurate method for planar electrodynamical structures natural wave spectrum investigations are the objects of this manuscript. The moment method with partial inversion operator method using may be considered as a basical way for solving this problem. This method is outlook for accurate analysis of different planar discontinuities in microstrip: such as step discontinuities, microstrip turns, Y- and X-junctions and etc., substrate space steps dielectric constants and other anisotropy types

  19. Quantitative cardiac phosphoproteomics profiling during ischemia-reperfusion in an immature swine model

    Energy Technology Data Exchange (ETDEWEB)

    Ledee, Dolena R.; Kang, Min A.; Kajimoto, Masaki; Purvine, Samuel O.; Brewer, Heather M.; Pasa Tolic, Ljiljana; Portman, Michael A.

    2017-07-01

    Ischemia-reperfusion (I/R) results in altered metabolic and molecular responses, and phosphorylation is one of the most noted regulatory mechanisms mediating signaling mechanisms during physiological stresses. To expand our knowledge of the potential phosphoproteomic changes in the myocardium during I/R, we used Isobaric Tags for Relative and Absolute Quantitation-based analyses in left ventricular samples obtained from porcine hearts under control or I/R conditions. The data are available via ProteomeXchange with identifier PXD006066. We identified 1,896 phosphopeptides within left ventricular control and I/R porcine samples. Significant differential phosphorylation between control and I/R groups was discovered in 111 phosphopeptides from 86 proteins. Analysis of the phosphopeptides using Motif-x identified five motifs: (..R..S..), (..SP..), (..S.S..), (..S…S..), and (..S.T..). Semiquantitative immunoblots confirmed site location and directional changes in phosphorylation for phospholamban and pyruvate dehydrogenase E1, two proteins known to be altered by I/R and identified by this study. Novel phosphorylation sites associated with I/R were also identified. Functional characterization of the phosphopeptides identified by our methodology could expand our understanding of the signaling mechanisms involved during I/R damage in the heart as well as identify new areas to target therapeutic strategies.

  20. Study of αB-Crystallin Expression in Gerbil BCAO Model of Transient Global Cerebral Ischemia

    Directory of Open Access Journals (Sweden)

    Ting Li

    2012-01-01

    Full Text Available αB-crystallin (α-BC, the fifth member of mammalian small heat shock protein family (HspB5, is known to be expressed in many tissues and has a distinctive interaction with cytoskeleton components. In this study, we investigated that α-BC and microtubule-associated protein-2 (MAP-2, a neuron-specific cytoskeleton protein, were coexpressed in neurons of Gerbil cortex, while in subcortex Gerbil brains, we found that several MAP-2-negative glia cells also express α-BC. When subjected to 10-minute bilateral carotid artery occlusion (BCAO, an increment was observed in α-BC-positive cells after 6-hour reperfusion and peaked at around 7 days after. In the same circumstances, the number and the staining concentration of MAP-2 positive neurons significantly decreased immediately after 6-hour reperfusion, followed by a slow recovery, which is consistent with the increase of α-BC. Our results suggested that α-BC plays an important role in brain ischemia, providing the early protection of neurons by giving intracellular supports through the maintenance of cytoskeleton and extracellular supports through the protection of glia cells.

  1. Antioxidant and antiapoptotic effects of erdosteine in a rat model of ovarian ischemia-reperfusion injury

    Directory of Open Access Journals (Sweden)

    Vedat Ugurel

    2017-01-01

    Full Text Available Objective(s: To evaluate the protective effect of erdosteine, an antiapoptotic and antioxidant agent, on torsion–detorsion evoked histopathological changes in experimental ovarian ischemia-reperfusion (IR injury. Materials and Methods: Eighteen female Wistar albino rats were used in control, IR, and IR+Edosteine (IR-E groups, (n=6 in each. The IR-E group received the erdosteine for seven days before the induction of torsion/retorsion, (10 mg/kg/days. The IR and IR-E groups were exposed to right unilateral adnexal torsion for 3 hr. Three hours later, re-laparotomy was performed, and the right ovaries were surgically excised. Oxidant and antioxidants levels were determined in serum. The ovarian tissue samples were received and fixed with 10% neutral buffered formalin. The sections were stained with H&E, anti-PCNA, and TUNEL. Results: The IR group were showed severe acute inflammation, polynuclear leukocytes and macrophages, stromal oedema and haemorrhage. Treatment with erdosteine in rats significantly retained degenerative changes in the ovaryPCNA (+ cell numbers were significantly decreased in the IR and IR-E groups unlike the control group. However, its numbers were significantly increased in the IR-E group unlike the IR group. TUNEL (+ cell numbers were significantly increased in the IR group unlike the control and the IR-E groups. In erdosteine treated group, TUNEL (+ cells were detected significantly less than the IR group (P

  2. Effect of 2-aminoethoxydiphenyl borate on ischemia-reperfusion injury in a rat ovary model.

    Science.gov (United States)

    Taskin, Mine Islimye; Hismiogullari, Adnan Adil; Yay, Arzu; Adali, Ertan; Gungor, Aysenur Cakir; Korkmaz, Gozde Ozge; Inceboz, Umit

    2014-07-01

    The aim of this study is to evaluate the effects of 2-aminoethoxydiphenyl borate (2-APB) as an antioxidant and analyze biochemical and histopathologic changes in experimental ischemia-reperfusion (I/R) injury in rat ovaries. Thirty female rats were utilized to create four groups. Group 1: I/R and 2-APB (2mg/kg); Group 2: I/R and 2-APB (4mg/kg); Group 3: I/R; Group 4: sham operation. Ovarian tissue and serum malondialdehyde, nitric oxide (NO) levels; ovarian tissue and serum total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI) were determined. In ovarian tissue samples histopathologic examination, immunoflourescence staining by TUNEL method was studied. Tissue TOS, serum TOS, and OSI levels were elevated in I/R group. After treatment with 2-APB, tissue and serum TOS levels and OSI levels were markedly decreased. There was a significant difference in terms of tissue and serum NO levels between the sham group and I/R group. Elevation in tissue NO and serum NO levels were decreased after treatment with 2-APB. TUNEL-positive cell number gradually decreased with dose of 2-APB in groups 1 and 2. Conservative treatment with 2-APB is beneficial for mitigation of I/R injury, and the ovarian protective effect of 2-APB appears to be mediated through its antiapopitotic and antioxidative effects. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  3. Study and optimization of the partial discharges in capacitor model ...

    African Journals Online (AJOL)

    The initial potential as well as the temperature are known to influence the partial discharge ... The development of electrostatic industry has ... the liquid impregnation. One of the ..... the Surface of Corona charged Uniforms layers of HIPS.

  4. The effect of melatonin on bacterial translocation following ischemia/reperfusion injury in a rat model of superior mesenteric artery occlusion.

    Science.gov (United States)

    Ozban, Murat; Aydin, Cagatay; Cevahir, Nural; Yenisey, Cigdem; Birsen, Onur; Gumrukcu, Gulistan; Aydin, Berrin; Berber, Ibrahim

    2015-03-08

    Acute mesenteric ischemia is a life-threatening vascular emergency resulting in tissue destruction due to ischemia-reperfusion injury. Melatonin, the primary hormone of the pineal gland, is a powerful scavenger of reactive oxygen species (ROS), including the hydroxyl and peroxyl radicals, as well as singlet oxygen, and nitric oxide. In this study, we aimed to investigate whether melatonin prevents harmful effects of superior mesenteric ischemia-reperfusion on intestinal tissues in rats. Rats were randomly divided into three groups, each having 10 animals. In group I, the superior mesenteric artery (SMA) was isolated but not occluded. In group II and group III, the SMA was occluded immediately distal to the aorta for 60 minutes. After that, the clamp was removed and the reperfusion period began. In group III, 30 minutes before the start of reperfusion, 10 mg/kg melatonin was administered intraperitonally. All animals were sacrified 24 hours after reperfusion. Tissue samples were collected to evaluate the I/R-induced intestinal injury and bacterial translocation (BT). There was a statistically significant increase in myeloperoxidase activity, malondialdehyde levels and in the incidence of bacterial translocation in group II, along with a decrease in glutathione levels. These investigated parameters were found to be normalized in melatonin treated animals (group III). We conclude that melatonin prevents bacterial translocation while precluding the harmful effects of ischemia/reperfusion injury on intestinal tissues in a rat model of superior mesenteric artery occlusion.

  5. Reactor modeling and process analysis for partial oxidation of natural gas

    NARCIS (Netherlands)

    Albrecht, B.A.

    2004-01-01

    This thesis analyses a novel process of partial oxidation of natural gas and develops a numerical tool for the partial oxidation reactor modeling. The proposed process generates syngas in an integrated plant of a partial oxidation reactor, a syngas turbine and an air separation unit. This is called

  6. Stochastic Modeling and Generation of Partially Polarized or Partially Coherent Electromagnetic Waves

    Science.gov (United States)

    Davis, Brynmor; Kim, Edward; Piepmeier, Jeffrey; Hildebrand, Peter H. (Technical Monitor)

    2001-01-01

    Many new Earth remote-sensing instruments are embracing both the advantages and added complexity that result from interferometric or fully polarimetric operation. To increase instrument understanding and functionality a model of the signals these instruments measure is presented. A stochastic model is used as it recognizes the non-deterministic nature of any real-world measurements while also providing a tractable mathematical framework. A stationary, Gaussian-distributed model structure is proposed. Temporal and spectral correlation measures provide a statistical description of the physical properties of coherence and polarization-state. From this relationship the model is mathematically defined. The model is shown to be unique for any set of physical parameters. A method of realizing the model (necessary for applications such as synthetic calibration-signal generation) is given and computer simulation results are presented. The signals are constructed using the output of a multi-input multi-output linear filter system, driven with white noise.

  7. Bayesian inference for partially identified models exploring the limits of limited data

    CERN Document Server

    Gustafson, Paul

    2015-01-01

    Introduction Identification What Is against Us? What Is for Us? Some Simple Examples of Partially Identified ModelsThe Road Ahead The Structure of Inference in Partially Identified Models Bayesian Inference The Structure of Posterior Distributions in PIMs Computational Strategies Strength of Bayesian Updating, Revisited Posterior MomentsCredible Intervals Evaluating the Worth of Inference Partial Identification versus Model Misspecification The Siren Call of Identification Comp

  8. Experimental models of brain ischemia: a review of techniques, magnetic resonance imaging and investigational cell-based therapies

    Directory of Open Access Journals (Sweden)

    Alessandra eCanazza

    2014-02-01

    Full Text Available Stroke continues to be a significant cause of death and disability worldwide. Although major advances have been made in the past decades in prevention, treatment and rehabilitation, enormous challenges remain in the way of translating new therapeutic approaches from bench to bedside. Thrombolysis, while routinely used for ischemic stroke, is only a viable option within a narrow time window. Recently, progress in stem cell biology has opened up avenues to therapeutic strategies aimed at supporting and replacing neural cells in infarcted areas. Realistic experimental animal models are crucial to understand the mechanisms of neuronal survival following ischemic brain injury and to develop therapeutic interventions. Current studies on experimental stroke therapies evaluate the efficiency of neuroprotective agents and cell-based approaches using primarily rodent models of permanent or transient focal cerebral ischemia. In parallel, advancements in imaging techniques permit better mapping of the spatial-temporal evolution of the lesioned cortex and its functional responses. This review provides a condensed conceptual review of the state of the art of this field, from models and magnetic resonance imaging techniques through to stem cell therapies.

  9. Human adipose-derived stem cell spheroid treated with photobiomodulation irradiation accelerates tissue regeneration in mouse model of skin flap ischemia.

    Science.gov (United States)

    Park, In-Su; Chung, Phil-Sang; Ahn, Jin Chul; Leproux, Anais

    2017-11-01

    Skin flap grafting is a form of transplantation widely used in plastic surgery. However, ischemia/reperfusion injury is the main factor which reduces the survival rate of flaps following grafting. We investigated whether photobiomodulation (PBM) precondition prior to human adipose-derived stromal cell (hASC) spheroid (PBM-spheroid) transplantation improved skin tissue functional recovery by the stimulation of angiogenesis and tissue regeneration in skin flap of mice. The LED had an emission wavelength peaked at 660 ± 20 nm (6 J/cm 2 , 10 mW/cm 2 ). The expression of angiogenic growth factors in PBM-spheroid hASCs was much greater than that of not-PBM-treated spheroid or monolayer-cultured hASCs. From immunochemical staining analysis, the hASCs of PBM-spheroid were CD31 + , KDR + , and CD34 + , whereas monolayer-cultured hASCs were negative for these markers. To evaluate the therapeutic effect of hASC PBM-spheroid in vivo, PBS, monolayer-cultured hASCs, and not-PBM-spheroid were transplanted into a skin flap model. The animals were observed for 14 days. The PBM-spheroid hASCs transplanted into the skin flap ischemia differentiated into endothelial cells and remained differentiated. Transplantation of PBM-spheroid hASCs into the skin flap ischemia significantly elevated the density of vascular formations through angiogenic factors released by the skin flap ischemia and enhanced tissue regeneration at the lesion site. Consistent with these results, the transplantation of PBM-spheroid hASCs significantly improved functional recovery compared with PBS, monolayer-cultured hASCs, and not-PBM-spheroid treatment. These findings suggest that transplantation of PBM-spheroid hASCs may be an effective stem cell therapy for the treatment of skin flap ischemia.

  10. Reduced PBR/TSPO Expression After Minocycline Treatment in a Rat Model of Focal Cerebral Ischemia: A PET Study Using [18F]DPA-714

    International Nuclear Information System (INIS)

    Martin, A.; Boisgard, R.; Tavitian, B.; Kassiou, M.; Dolle, F.

    2011-01-01

    Background: Many new candidate pharmaceuticals designed to improve recovery after stroke have been proposed recently, but there are still too few molecular imaging methods capable to assess their efficacy. A hallmark of the inflammatory reaction that follows focal cerebral ischemia is overexpression of the mitochondrial peripheral benzodiazepine receptor/18 kDa translocator protein (PBR/TSPO) in the monocytic lineage and astrocytes. This overexpression can be imaged with positron emission tomography (PET) using PBR/TSPO-selective radioligands such as [ 18 F]DPA-714. Purpose: Here, we tested whether PET with [ 18 F]DPA-714 would evidence the effect of minocycline, a broad spectrum antibiotic presently tested as neuro-protective agent after stroke, on the inflammatory reaction induced in an experimental model of stroke. Procedures: Ten rats were subjected to a 2-h transient middle cerebral artery occlusion with reperfusion. Minocycline or saline was intravenously administrated 1 h after reperfusion and daily during the following 6 days. PET studies were performed using [ 18 F]DPA-714 at 7 days after cerebral ischemia. Results: In vivo PET imaging showed a significant decrease in [ 18 F]DPA-714 uptake at 7 days after cerebral ischemia in rats treated with minocycline with respect to saline-treated animals. Minocycline treatment had no effect on the size of the infarcted area. Conclusion: Minocycline administered daily during 7 days after ischemia decreases [ 18 F]DPA- 714 binding, suggesting that the drug exerts an anti-inflammatory activity. [ 18 F]DPA-714 PET is a useful bio-marker to study novel anti-inflammatory strategies in experimental cerebral ischemia. (authors)

  11. Cardiac function improved by sarcoplasmic reticulum Ca2+-ATPase overexpression in a heart failure model induced by chronic myocardial ischemia

    Directory of Open Access Journals (Sweden)

    Wei XIN

    2011-04-01

    Full Text Available Objective Chronic myocardial ischemia(CMI has become an important cause of heart failure(HF.The aim of present study was to examine the effects of Sarco-endoplasmic reticulum calcium ATPase(SERCA2a gene transfer in HF model in large animal induced by CMI.Methods HF was reproduced in minipigs by ligating the initial segment of proximal left anterior descending(LAD coronary artery with an ameroid constrictor to produce progressive vessel occlusion and ischemia.After confirmation of myocardial perfusion defect and cardiac function impairment by SPECT and echocardiography in the model,animals were divided into 4 groups: HF group;HF+enhanced green fluorescent protein(EGFP group;HF+SERCA2a group;and sham operation group as control.rAAV1-EGFP and rAAV1-SERCA2a(1×1012 vg for each animal were directly and intramyocardially injected to the animals of HF+EGFP and HF+SERCA2a groups.Sixty days after the gene transfer,the expression of SERCA2a at the protein level was examined by Western blotting and immunohistochemistry,the changes in cardiac function were determined by echocardiographic and hemodynamic analysis,and the changes in serum inflammatory and neuro-hormonal factors(including BNP,TNF-a,IL-6,ET-1 and Ang II were determined by radioimmunoassay.Results Sixty days after gene transfer,LVEF,Ev/Av and ±dp/dtmax increased significantly(P < 0.05,along with an increase of SERCA2a protein expression in the ischemic myocardium(PP < 0.05,accompanied by a significant decrease of inflammatory and neural-hormonal factors(PP < 0.05 in HF+SERCA2a group as compared with HF/HF+EGFP group.Conclusions Overexpression of SERCA2a may significantly improve the cardiac function of the ischemic myocardium of HF model induced by CMI and reverse the activation of neural-hormonal factors,implying that it has a potential therapeutic significance in CMI related heart failure.

  12. An Introduction to the Partial Credit Model for Developing Nursing Assessments.

    Science.gov (United States)

    Fox, Christine

    1999-01-01

    Demonstrates how the partial credit model, a variation of the Rasch Measurement Model, can be used to develop performance-based assessments for nursing education. Applies the model using the Practical Knowledge Inventory for Nurses. (SK)

  13. Transplanted Dental Pulp Stem Cells Migrate to Injured Area and Express Neural Markers in a Rat Model of Cerebral Ischemia.

    Science.gov (United States)

    Zhang, Xuemei; Zhou, Yinglian; Li, Hulun; Wang, Rui; Yang, Dan; Li, Bing; Cao, Xiaofang; Fu, Jin

    2018-01-01

    Ischemic stroke is a major cause of disability and mortality worldwide, while effective restorative treatments are limited at present. Stem cell transplantation holds therapeutic potential for ischemic vascular diseases and may provide an opportunity for neural regeneration. Dental pulp stem cells (DPSCs) origin from neural crest and have neuro-ectodermal features including proliferation and multilineage differentiation potentials. The rat model of middle cerebral artery occlusion (MCAO) was used to evaluate whether intravenous administration of DPSCs can reduce infarct size and to estimate the migration and trans-differentiation into neuron-like cells in focal cerebral ischemia models. Brain tissues were collected at 4 weeks following cell transplantation and analyzed with immunofluorescence, immunohistochemistry and real-time polymerase chain reaction (RT-PCR) methods. Intravenously administration of rat-derived DPSCs were found to migrate into the boundary of ischemic areas and expressed neural specific markers, reducing infarct volume and cerebral edema. These results suggest that DPSCs treatment may serve as a potential therapy for clinical stroke patients in the future. © 2018 The Author(s). Published by S. Karger AG, Basel.

  14. Early small-bowel ischemia: dual-energy CT improves conspicuity compared with conventional CT in a swine model.

    Science.gov (United States)

    Potretzke, Theodora A; Brace, Christopher L; Lubner, Meghan G; Sampson, Lisa A; Willey, Bridgett J; Lee, Fred T

    2015-04-01

    To compare dual-energy computed tomography (CT) with conventional CT for the detection of small-bowel ischemia in an experimental animal model. The study was approved by the animal care and use committee and was performed in accordance with the Guide for Care and Use of Laboratory Animals issued by the National Research Council. Ischemic bowel segments (n = 8) were created in swine (n = 4) by means of surgical occlusion of distal mesenteric arteries and veins. Contrast material-enhanced dual-energy CT and conventional single-energy CT (120 kVp) sequences were performed during the portal venous phase with a single-source fast-switching dual-energy CT scanner. Attenuation values and contrast-to-noise ratios of ischemic and perfused segments on iodine material-density, monospectral dual-energy CT (51 keV, 65 keV, and 70 keV), and conventional 120-kVp CT images were compared. Linear mixed-effects models were used for comparisons. The attenuation difference between ischemic and perfused segments was significantly greater on dual-energy 51-keV CT images than on conventional 120-kVp CT images (mean difference, 91.7 HU vs 47.6 HU; P conventional CT by increasing attenuation differences between ischemic and perfused segments on low-kiloelectron volt and iodine material density images. © RSNA, 2014.

  15. In vitro and in vivo models of cerebral ischemia show discrepancy in therapeutic effects of M2 macrophages.

    Directory of Open Access Journals (Sweden)

    Virginie Desestret

    Full Text Available THE INFLAMMATORY RESPONSE FOLLOWING ISCHEMIC STROKE IS DOMINATED BY INNATE IMMUNE CELLS: resident microglia and blood-derived macrophages. The ambivalent role of these cells in stroke outcome might be explained in part by the acquisition of distinct functional phenotypes: classically (M1 and alternatively activated (M2 macrophages. To shed light on the crosstalk between hypoxic neurons and macrophages, an in vitro model was set up in which bone marrow-derived macrophages were co-cultured with hippocampal slices subjected to oxygen and glucose deprivation. The results showed that macrophages provided potent protection against neuron cell loss through a paracrine mechanism, and that they expressed M2-type alternative polarization. These findings raised the possibility of using bone marrow-derived M2 macrophages in cellular therapy for stroke. Therefore, 2 million M2 macrophages (or vehicle were intravenously administered during the subacute stage of ischemia (D4 in a model of transient middle cerebral artery occlusion. Functional neuroscores and magnetic resonance imaging endpoints (infarct volumes, blood-brain barrier integrity, phagocytic activity assessed by iron oxide uptake were longitudinally monitored for 2 weeks. This cell-based treatment did not significantly improve any outcome measure compared with vehicle, suggesting that this strategy is not relevant to stroke therapy.

  16. Study and optimization of the partial discharges in capacitor model ...

    African Journals Online (AJOL)

    that the main cause of failure of these devices is the appearance of partial discharges initiated on edges of armatures. These devices can quickly slam if discharges occur continuously during the liquid impregnation. One of the criteria for selecting impregnating liquids is the behavior of gas bubbles when discharges occur.

  17. Partial delegation in a model of currency crisis

    OpenAIRE

    Boinet, V

    2002-01-01

    Stressing the inßuence of expected devaluation on currency crises, this paper shows that, in a Þxed exchange-rate system with an escape clause, partial delegation of exchange-rate policy to an inßation-averse central banker reduces the probability of crisis.

  18. Partial-factor Energy Efficiency Model of Indonesia

    OpenAIRE

    Nugroho Fathul; Syaifudin Noor

    2018-01-01

    This study employs the partial-factor energy efficiency to reveal the relationships between energy efficiency and the consumption of both, the renewable energy and non-renewable energy in Indonesia. The findings confirm that consumption of non-renewable energy will increase the inefficiency in energy consumption. On the other side, the use of renewable energy will increase the energy efficiency in Indonesia. As the result, the Government of Indonesia may address this issue by providing more s...

  19. Pretreatment with Fish Oil-Based Lipid Emulsion Modulates Muscle Leukocyte Chemotaxis in Murine Model of Sublethal Lower Limb Ischemia

    Directory of Open Access Journals (Sweden)

    Yao-Ming Shih

    2017-01-01

    Full Text Available This study investigated the effects of a fish oil- (FO- based lipid emulsion on muscle leukocyte chemotaxis and inflammatory responses in a murine model of limb ischemia-reperfusion (IR injury. Mice were assigned randomly to 1 sham (sham group, 2 ischemic groups, and 2 IR groups. The sham group did not undergo the ischemic procedure. The mice assigned to the ischemic or IR groups were pretreated intraperitoneally with either saline or FO-based lipid emulsion for 3 consecutive days. The IR procedure was induced by applying a 4.5 oz orthodontic rubber band to the left thigh above the greater trochanter for 120 min and then cutting the band to allow reperfusion. The ischemic groups were sacrificed immediately while the IR groups were sacrificed 24 h after reperfusion. Blood, IR-injured gastrocnemius, and lung tissues were collected for analysis. The results showed that FO pretreatment suppressed the local and systemic expression of several IR-induced proinflammatory mediators. Also, the FO-pretreated group had lower blood Ly6ChiCCR2hi monocyte percentage and muscle M1/M2 ratio than the saline group at 24 h after reperfusion. These findings suggest that FO pretreatment may have a protective role in limb IR injury by modulating the expression of proinflammatory mediators and regulating the polarization of macrophage.

  20. L-carnitine pretreatment protects slow-twitch skeletal muscles in a rat model of ischemia-reperfusion injury.

    Science.gov (United States)

    Demirel, Mert; Kaya, Burak; Cerkez, Cem; Ertunc, Mert; Sara, Yildirim

    2013-10-01

    Ischemia-reperfusion (I/R) injury negatively affects the outcome of surgical interventions for amputated or severely traumatized extremities. This study aimed to evaluate the protective role of l-carnitine on the contractile properties of fast-twitch (extensor digitorum longus [EDL]) and slow-twitch (soleus [SOL]) skeletal muscles following I/R-induced injury in a rat model. Rats were divided into 4 groups (1) saline pretreatment, (2) l-carnitine pretreatment, (3) saline pretreatment and I/R, and (4) l-carnitine pretreatment and I/R. Twitch and tetanic contractions in the EDL and SOL muscles in each group were recorded. Additionally, a fatigue protocol was performed in these muscles. Twitch and tetanic contraction amplitudes were lower in the EDL and SOL muscles in which I/R was induced (P contraction amplitude in the SOL muscles following I/R (P muscles. l-Carnitine pretreatment did not alter the fatigue response in any of the muscles.

  1. Anti-inflammatory and antioxidant effects of infliximab in a rat model of intestinal ischemia/reperfusion injury.

    Science.gov (United States)

    Pergel, Ahmet; Kanter, Mehmet; Yucel, Ahmet Fikret; Aydin, Ibrahim; Erboga, Mustafa; Guzel, Ahmet

    2012-11-01

    The aim of this study was to investigate the possible protective effects of infliximab on oxidative stress, cell proliferation and apoptosis in the rat intestinal mucosa after ischemia/reperfusion (I/R). A total of 30 male Wistar albino rats were divided into three groups: sham, I/R and I/R+ infliximab; each group comprised 10 animals. Sham group animals underwent laparotomy without I/R injury. I/R groups after undergoing laparotomy, 1 hour of superior mesenteric artery ligation occurred, which was followed by 1 hour of reperfusion. In the infliximab group, 3 days before I/R, infliximab (3 mg/kg) was administered intravenously. All animals were killed at the end of reperfusion and intestinal tissues samples were obtained for biochemical and histopathological investigation in all groups. To date, no biochemical and histopathological changes have been reported regarding intestinal I/R injury in rats due to infliximab treatment. Infliximab treatment significantly decreased the elevated tissue malondialdehyde levels and increased reduced superoxide dismutase and glutathione peroxidase enzyme activities in intestinal tissues samples. I/R caused severe histopathological injury including mucosal erosions, inflammatory cell infiltration, necrosis, hemorrhage, and villous congestion. Infliximab treatment significantly attenuated the severity of intestinal I/R injury, inhibiting I/R-induced apoptosis, and cell proliferation. Because of its anti-inflammatory and antioxidant effects, infliximab pretreatment may have protective effects on the experimental intestinal I/R model of rats.

  2. Adenovirus-mediated E2-EPF UCP gene transfer prevents autoamputation in a mouse model of hindlimb ischemia.

    Science.gov (United States)

    Lim, Jung Hwa; Shin, Hyo Jung; Park, Kyeong-Su; Lee, Chan Hee; Jung, Cho-Rok; Im, Dong-Soo

    2012-04-01

    E2-EPF ubiquitin carrier protein (UCP) stabilizes hypoxia-inducible factor-1α (HIF-1α) inducing ischemic vascular responses. Here, we investigated the effect of UCP gene transfer on therapeutic angiogenesis. Adenovirus-encoded UCP (Ad-F-UCP) increased the expression of vascular endothelial growth factor (VEGF) and fibroblast growth factor-2 (FGF-2) in cells and mice. Conditioned media from UCP-overexpressing cells promoted proliferation, tubule formation, and invasion of human umbilical-vascular-endothelial cells (HUVECs), and vascularization in chorioallantoic membrane (CAM) assay. Ad-F-UCP increased the vessel density in the Martigel plug assay, and generated copious vessel-like structures in the explanted muscle. The UCP effect on angiogenesis was dependent on VEGF and FGF-2. In mouse hindlimb ischemia model (N = 30/group), autoamputation (limb loss) occurred in 87% and 68% of the mice with saline and Ad encoding β-galactosidase (Ad-LacZ), respectively, whereas only 23% of the mice injected with Ad-F-UCP showed autoamputation after 21 days of treatment. Ad-F-UCP increased protein levels of HIF-1α, platelet-endothelial cell adhesion molecule-1 (PECAM-1), smooth muscle cell actin (SMA) in the ischemic muscle, and augmented blood vessels doubly positive for PECAM-1 and SMA. Consequently, UCP gene transfer prevented muscle degeneration and autoamputation of ischemic limb. The results suggest that E2-EPF UCP may be a target for therapeutic angiogenesis.

  3. Stepwise Analysis of Differential Item Functioning Based on Multiple-Group Partial Credit Model.

    Science.gov (United States)

    Muraki, Eiji

    1999-01-01

    Extended an Item Response Theory (IRT) method for detection of differential item functioning to the partial credit model and applied the method to simulated data using a stepwise procedure. Then applied the stepwise DIF analysis based on the multiple-group partial credit model to writing trend data from the National Assessment of Educational…

  4. An Extension of the Partial Credit Model with an Application to the Measurement of Change.

    Science.gov (United States)

    Fischer, Gerhard H.; Ponocny, Ivo

    1994-01-01

    An extension to the partial credit model, the linear partial credit model, is considered under the assumption of a certain linear decomposition of the item x category parameters into basic parameters. A conditional maximum likelihood algorithm for estimating basic parameters is presented and illustrated with simulation and an empirical study. (SLD)

  5. Preliminary evaluation of [1-11C]octanoate as a PET tracer for studying cerebral ischemia. A PET study in rat and canine models of focal cerebral ischemia

    International Nuclear Information System (INIS)

    Kuge, Yuji; Kawashima, Hidefumi; Hashimoto, Tadatoshi

    2000-01-01

    Octanoate is taken up into the brain and is converted in astrocytes to glutamine through the tricarboxylic acid (TCA) cycle after β-oxidation. We speculate that [1- 11 C]octanoate may be used as a tracer for astroglial functions and/or fatty acid metabolism in the brain and may be useful for studying cerebral ischemia. In the present study we investigated brain distribution of [1- 11 C]octanoate and compared it with cerebral blood flow (CBF) by using rat and canine models of middle cerebral artery (MCA) occlusion and a high resolution PET. In rats brain distribution of [ 15 O]H 2 O measured 1-2 h and 5-6 h after insult was compared with that of [1- 11 C]octanoate measured 3-4 h after insult. Radioactivity ratios of lesioned to normal hemispheres determined with [ 15 O]H 2 O were lower than those determined with [1- 11 C]octanoate. These results were confirmed by a study on a canine model of MCA-occlusion. Twenty-four hours after insult, CBF decreased in the MCA-territory of the occluded hemisphere, whereas normal or higher accumulation of [1- 11 C]octanoate was observed in the ischemic regions. The uptake of [1- 11 C]octanoate-derived radioactivity therefore increased relative to CBF in the ischemic regions, indicating that [1- 11 C]octanoate provides functional information different from CBF. In conclusion, we found that [1- 11 C]octanoate is a potential radiopharmaceutical for studying the pathophysiology of cerebral ischemia. (author)

  6. Mathematical Modeling of Early Cellular Innate and Adaptive Immune Responses to Ischemia/Reperfusion Injury and Solid Organ Allotransplantation

    Science.gov (United States)

    Day, Judy D.; Metes, Diana M.; Vodovotz, Yoram

    2015-01-01

    A mathematical model of the early inflammatory response in transplantation is formulated with ordinary differential equations. We first consider the inflammatory events associated only with the initial surgical procedure and the subsequent ischemia/reperfusion (I/R) events that cause tissue damage to the host as well as the donor graft. These events release damage-associated molecular pattern molecules (DAMPs), thereby initiating an acute inflammatory response. In simulations of this model, resolution of inflammation depends on the severity of the tissue damage caused by these events and the patient’s (co)-morbidities. We augment a portion of a previously published mathematical model of acute inflammation with the inflammatory effects of T cells in the absence of antigenic allograft mismatch (but with DAMP release proportional to the degree of graft damage prior to transplant). Finally, we include the antigenic mismatch of the graft, which leads to the stimulation of potent memory T cell responses, leading to further DAMP release from the graft and concomitant increase in allograft damage. Regulatory mechanisms are also included at the final stage. Our simulations suggest that surgical injury and I/R-induced graft damage can be well-tolerated by the recipient when each is present alone, but that their combination (along with antigenic mismatch) may lead to acute rejection, as seen clinically in a subset of patients. An emergent phenomenon from our simulations is that low-level DAMP release can tolerize the recipient to a mismatched allograft, whereas different restimulation regimens resulted in an exaggerated rejection response, in agreement with published studies. We suggest that mechanistic mathematical models might serve as an adjunct for patient- or sub-group-specific predictions, simulated clinical studies, and rational design of immunosuppression. PMID:26441988

  7. Stanniocalcin-1 Protects a Mouse Model from Renal Ischemia-Reperfusion Injury by Affecting ROS-Mediated Multiple Signaling Pathways.

    Science.gov (United States)

    Liu, Dajun; Shang, Huiping; Liu, Ying

    2016-07-12

    Stanniocalcin-1 (STC-1) protects against renal ischemia-reperfusion injury (RIRI). However, the molecular mechanisms remain widely unknown. STC-1 inhibits reactive oxygen species (ROS), whereas most ROS-mediated pathways are associated with ischemic injury. Therefore, to explore the mechanism, the effects of STC-1 on ROS-medicated pathways were studied. Non-traumatic vascular clamps were used to establish RIRI mouse models. The serum levels of STC-1, interleukin-6 (IL-6), interferon (IFN) γ, P53, and capase-3 were measured by ELISA kits. Superoxide dismutase (SOD) and malondialdehyde (MDA) were measured by fluorescence spectrofluorometer. All these molecules changed significantly in a RIRI model mouse when compared with those in a sham control. Kidney cells were isolated from sham and model mice. STC-1 was overexpressed or knockout in these kidney cells. The molecules in ROS-medicated pathways were measured by real-time quantitative PCR and Western blot. The results showed that STC-1 is an effective ROS scavenger. The serum levels of STC-1, MDA and SOD activity were increased while the serum levels of IL-6, iIFN-γ, P53, and capase-3 were decreased in a model group when compared with a sham control (p ROS-mediated molecules. Therefore, STC-1 maybe improve anti-inflammation, anti-oxidant and anti-apoptosis activities by affecting ROS-mediated pathways, especially the phospho-modifications of the respective proteins, resulting in the increase of SOD and reduce of capase-3, p53, IL-6 and IFN-γ.

  8. The effects of Mucuna pruriens extract on histopathological and biochemical features in the rat model of ischemia.

    Science.gov (United States)

    Nayak, Vanishri S; Kumar, Nitesh; D'Souza, Antony S; Nayak, Sunil S; Cheruku, Sri P; Pai, K Sreedhara Ranganath

    2017-12-13

    Stroke is considered to be one of the most important causes of death worldwide. Global ischemia causes widespread brain injury and infarctions in various regions of the brain. Oxidative stress can be considered an important factor in the development of tissue damage, which is caused because of arterial occlusion with subsequent reperfusion. Kapikacchu or Mucuna pruriens, commonly known as velvet bean, is well known for its aphrodisiac activities. It is also used in the treatment of snakebites, depressive neurosis, and Parkinson's disease. Although this plant has different pharmacological actions, its neuroprotective activity has received minimal attention. Thus, this study was carried out with the aim of evaluating the neuroprotective action of M. pruriens in bilateral carotid artery occlusion-induced global cerebral ischemia in Wistar rats. The carotid arteries of both sides were occluded for 30 min and reperfused to induce global cerebral ischemia. The methanolic plant extract was administered to the study animals for 10 days. The brains of the Wistar rats were isolated by decapitation and observed for histopathological and biochemical changes. Cerebral ischemia resulted in significant neurological damage in the brains of the rats that were not treated by M. pruriens. The group subjected to treatment by the M. pruriens extract showed significant protection against brain damage compared with the negative control group, which indicates the therapeutic potential of this plant in ischemia.

  9. Partial Portal Vein Arterialization Attenuates Acute Bile Duct Injury Induced by Hepatic Dearterialization in a Rat Model.

    Science.gov (United States)

    Jiang, Jun; Wei, Jishu; Wu, Junli; Gao, Wentao; Li, Qiang; Jiang, Kuirong; Miao, Yi

    2016-01-01

    Hepatic infarcts or abscesses occur after hepatic artery interruption. We explored the mechanisms of hepatic deprivation-induced acute liver injury and determine whether partial portal vein arterialization attenuated this injury in rats. Male Sprague-Dawley rats underwent either complete hepatic arterial deprivation or partial portal vein arterialization, or both. Hepatic ischemia was evaluated using biochemical analysis, light microscopy, and transmission electron microscopy. Hepatic ATP levels, the expression of hypoxia- and inflammation-associated genes and proteins, and the expression of bile transporter genes were assessed. Complete dearterialization of the liver induced acute liver injury, as evidenced by the histological changes, significantly increased serum biochemical markers, decreased ATP content, increased expression of hypoxia- and inflammation-associated genes and proteins, and decreased expression of bile transporter genes. These detrimental changes were extenuated but not fully reversed by partial portal vein arterialization, which also attenuated ductular reaction and fibrosis in completely dearterialized rat livers. Collectively, complete hepatic deprivation causes severe liver injury, including bile infarcts and biloma formation. Partial portal vein arterialization seems to protect against acute ischemia-hypoxia-induced liver injury.

  10. Partial Portal Vein Arterialization Attenuates Acute Bile Duct Injury Induced by Hepatic Dearterialization in a Rat Model

    Directory of Open Access Journals (Sweden)

    Jun Jiang

    2016-01-01

    Full Text Available Hepatic infarcts or abscesses occur after hepatic artery interruption. We explored the mechanisms of hepatic deprivation-induced acute liver injury and determine whether partial portal vein arterialization attenuated this injury in rats. Male Sprague-Dawley rats underwent either complete hepatic arterial deprivation or partial portal vein arterialization, or both. Hepatic ischemia was evaluated using biochemical analysis, light microscopy, and transmission electron microscopy. Hepatic ATP levels, the expression of hypoxia- and inflammation-associated genes and proteins, and the expression of bile transporter genes were assessed. Complete dearterialization of the liver induced acute liver injury, as evidenced by the histological changes, significantly increased serum biochemical markers, decreased ATP content, increased expression of hypoxia- and inflammation-associated genes and proteins, and decreased expression of bile transporter genes. These detrimental changes were extenuated but not fully reversed by partial portal vein arterialization, which also attenuated ductular reaction and fibrosis in completely dearterialized rat livers. Collectively, complete hepatic deprivation causes severe liver injury, including bile infarcts and biloma formation. Partial portal vein arterialization seems to protect against acute ischemia-hypoxia-induced liver injury.

  11. Efficient semiparametric estimation in generalized partially linear additive models for longitudinal/clustered data

    KAUST Repository

    Cheng, Guang; Zhou, Lan; Huang, Jianhua Z.

    2014-01-01

    We consider efficient estimation of the Euclidean parameters in a generalized partially linear additive models for longitudinal/clustered data when multiple covariates need to be modeled nonparametrically, and propose an estimation procedure based

  12. Evaluation of kidney repair capacity using 99mTc-DMSA in ischemia/reperfusion injury models.

    Science.gov (United States)

    Kwak, Wonjung; Jang, Hee-Seong; Belay, Takele; Kim, Jinu; Ha, Yeong Su; Lee, Sang Woo; Ahn, Byeong-Cheol; Lee, Jaetae; Park, Kwon Moo; Yoo, Jeongsoo

    2011-03-04

    Quantitative (99m)Tc-DMSA renal uptake was studied in different renal ischemia/reperfusion (I/R) mice models for the assessment of renal repair capacity. Mice models of nephrectomy, uni- and bi-lateral I/R together with sham-operated mice were established. At 1h, 1d, 4d, 1, 2 and 3 wk after I/R, (99m)Tc-DMSA (27.7 ± 1.3 MBq) was injected via tail vein and after 3h post-injection, the mice were scanned for 30 min with pinhole equipped gamma camera. Higher uptake of (99m)Tc-DMSA was measured in normal kidneys of uni-lateral I/R model and nephrectomized kidney I/R model at 3 wk post-surgery. Comparing the restoration capacities of the affected kidneys of nephrectomy, uni- and bi-lateral I/R models, higher repair capacity was observed in the nephrectomized model followed by bi-lateral then uni-lateral models. The normal kidney may retard the restoration of damaged kidney in uni-lateral I/R model. Moreover, 3 wk after Uni-I/R, the size of injured kidney was significantly smaller than non-ischemic contralateral and sham operated kidneys, while nephrectomy I/R kidneys were significantly enlarged compared to all others at 3 wk post-surgery. Very strong correlation between (99m)Tc-DMSA uptake and weight of dissected kidneys in I/R models was observed. Consistent with (99m)Tc-DMSA uptake results, all histological results indicate that kidney recovery after injury is correlated with the amount of intact tubules and kidney sizes. In summary, our study showed good potentials of (99m)Tc-DMSA scan as a promising non-invasive method for evaluation of kidney restoration after I/R injuries. Interestingly, mice with Bi-I/R injury showed faster repair capacity than those with uni-I/R. Copyright © 2011 Elsevier Inc. All rights reserved.

  13. Hemorheological and metabolic consequences of renal ischemia-reperfusion and their modulation by N,N-dimethyl-tryptamine on a rat model.

    Science.gov (United States)

    Peto, Katalin; Nemeth, Norbert; Mester, Anita; Magyar, Zsuzsanna; Ghanem, Souleiman; Somogyi, Viktoria; Tanczos, Bence; Deak, Adam; Bidiga, Laszlo; Frecska, Ede; Nemes, Balazs

    2018-04-13

    Micro-rheological relations of renal ischemia-reperfusion (I/R) have not been completely elucidated yet. Concerning anti-inflammatory agents, it is supposed that sigma-1 receptor agonist N,N-dimethyl-tryptamin (DMT) can be useful to reduce I/R injury. To investigate the micro-rheological and metabolic parameters, and the effects of DMT in renal I/R in rats. In anesthetized rats from median laparotomy both kidneys were exposed. In Control group (n = 6) no other intervention happened. In I/R group (n = 10) the right renal vessels were ligated and after 60 minutes the organ was removed. The left renal vessels were clamped for 60 minutes followed by 120-minute reperfusion. In I/R+DMT group (n = 10) DMT was administered 15 minutes before the ischemia. Blood samples were taken before/after ischemia and during the reperfusion for testing hematological, metabolic parameters, erythrocyte deformability and aggregation. Lactate concentration significantly increased and accompanied with decreased blood pH. Enhanced erythrocyte aggregation and impaired deformability were observed from the 30th minute of reperfusion. In I/R+DMT group we found diminished changes compared to the I/R group (lactate, pH, electrolytes, red blood cell deformability and aggregation). Metabolic and micro-rheological parameters impair during renal I/R. DMT could reduce but not completely prevent the changes in this rat model.

  14. Functional and structural correlates of magnetic resonance patterns in a new in vitro model of cerebral ischemia by transient occlusion of the medial cerebral artery.

    Science.gov (United States)

    Breschi, Gian Luca; Librizzi, Laura; Pastori, Chiara; Zucca, Ileana; Mastropietro, Alfonso; Cattalini, Alessandro; de Curtis, Marco

    2010-08-01

    Magnetic resonance imaging (MRI) during the acute phase of a stroke contributes to recognize ischemic regions and is potentially useful to predict clinical outcome. Yet, the functional significance of early MRI alterations during brain ischemia is not clearly understood. We achieved an experimental study to interpret MRI signals in a novel model of focal ischemia in the in vitro isolated guinea pig brain. By combining neurophysiological and morphological analysis with MR-imaging, we evaluated the suitability of MR to identify ischemic and peri-ischemic regions. Extracellular recordings demonstrated depolarizations in the ischemic core, but not in adjacent areas, where evoked activity was preserved and brief peri-infarct depolarizations occurred. Diffusion-weighted MRI and immunostaining performed after neurophysiological characterization showed changes restricted to the core region. Diffusion-weighted MR alterations did not include the penumbra region characterized by peri-infarct depolarizations. Therefore, by comparing neurophysiological, imaging and anatomical data, we can conclude that DW-MRI underestimates the extension of the tissue damage involved in brain ischemia.

  15. Receptor for advanced glycation end products involved in lung ischemia reperfusion injury in cardiopulmonary bypass attenuated by controlled oxygen reperfusion in a canine model.

    Science.gov (United States)

    Rong, Jian; Ye, Sheng; Liang, Meng-ya; Chen, Guang-xian; Liu, Hai; Zhang, Jin-Xin; Wu, Zhong-kai

    2013-01-01

    Controlled oxygen reperfusion could protect the lung against ischemia-reperfusion injury in cardiopulmonary bypass (CPB) by downregulating high mobility group box 1 (HMGB1), a high affinity receptor of HMGB1. This study investigated the effect of controlled oxygen reperfusion on receptor for advanced glycation end products (RAGE) expression and its downstream effects on lung ischemia-reperfusion injury. Fourteen canines received CPB with 60 minutes of aortic clamping and cardioplegic arrest followed by 90 minutes of reperfusion. Animals were randomized to receive 80% FiO2 during the entire procedure (control group) or to a test group receiving a controlled oxygen reperfusion protocol. Pathologic changes in lung tissues, RAGE expression, serum interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) were evaluated. The lung pathologic scores after 25 and 90 minutes of reperfusion were significantly lower in the test group compared with the control group (p RAGE expression, TNF-α, and IL-6 were downregulated by controlled oxygen treatment (p RAGE might be involved in the lung ischemia-reperfusion injury in canine model of CPB, which was downregulated by controlled oxygen reperfusion.

  16. Inhibition of Fas-associated death domain-containing protein (FADD protects against myocardial ischemia/reperfusion injury in a heart failure mouse model.

    Directory of Open Access Journals (Sweden)

    Qian Fan

    Full Text Available As technological interventions treating acute myocardial infarction (MI improve, post-ischemic heart failure increasingly threatens patient health. The aim of the current study was to test whether FADD could be a potential target of gene therapy in the treatment of heart failure.Cardiomyocyte-specific FADD knockout mice along with non-transgenic littermates (NLC were subjected to 30 minutes myocardial ischemia followed by 7 days of reperfusion or 6 weeks of permanent myocardial ischemia via the ligation of left main descending coronary artery. Cardiac function were evaluated by echocardiography and left ventricular (LV catheterization and cardiomyocyte death was measured by Evans blue-TTC staining, TUNEL staining, and caspase-3, -8, and -9 activities. In vitro, H9C2 cells transfected with ether scramble siRNA or FADD siRNA were stressed with chelerythrin for 30 min and cleaved caspase-3 was assessed.FADD expression was significantly decreased in FADD knockout mice compared to NLC. Ischemia/reperfusion (I/R upregulated FADD expression in NLC mice, but not in FADD knockout mice at the early time. FADD deletion significantly attenuated I/R-induced cardiac dysfunction, decreased myocardial necrosis, and inhibited cardiomyocyte apoptosis. Furthermore, in 6 weeks long term permanent ischemia model, FADD deletion significantly reduced the infarct size (from 41.20 ± 3.90% in NLC to 26.83 ± 4.17% in FADD deletion, attenuated myocardial remodeling, improved cardiac function and improved survival. In vitro, FADD knockdown significantly reduced chelerythrin-induced the level of cleaved caspase-3.Taken together, our results suggest FADD plays a critical role in post-ischemic heart failure. Inhibition of FADD retards heart failure progression. Our data supports the further investigation of FADD as a potential target for genetic manipulation in the treatment of heart failure.

  17. Protective effects of Naringin in a rat model of spinal cord ischemia ...

    African Journals Online (AJOL)

    generation and downregulating inflammatory markers in an SCI rat model. Keywords: Naringin ... intestinal microflora to yield a metabolite called naringenin ... disease (PD). Moreover .... CAT was significantly reduced in SCII rats compared ...

  18. Partially linear varying coefficient models stratified by a functional covariate

    KAUST Repository

    Maity, Arnab; Huang, Jianhua Z.

    2012-01-01

    We consider the problem of estimation in semiparametric varying coefficient models where the covariate modifying the varying coefficients is functional and is modeled nonparametrically. We develop a kernel-based estimator of the nonparametric

  19. A Comparison of Graded Response and Rasch Partial Credit Models with Subjective Well-Being.

    Science.gov (United States)

    Baker, John G.; Rounds, James B.; Zevon, Michael A.

    2000-01-01

    Compared two multiple category item response theory models using a data set of 52 mood terms with 713 undergraduate psychology students. Comparative model fit for the Samejima (F. Samejima, 1966) logistic model for graded responses and the Masters (G. Masters, 1982) partial credit model favored the former model for this data set. (SLD)

  20. Transplantation of MSCs in combination with netrin-1 improves neoangiogenesis in a rat model of hind limb ischemia.

    Science.gov (United States)

    Li, Qian; Yao, Dan; Ma, Jianhua; Zhu, Jian; Xu, Xianghong; Ren, Yunli; Ding, Xinsheng; Mao, Xiaoming

    2011-03-01

    Similar to the neural network, the vascular network is formed from central axial structures that send sprouts along predetermined trajectories to their distal destinations. Indeed, recent evidence indicates that neuronal guidance factors and their receptors function as angiogenic regulators. As neural guidance cues, netrin-1 is the most extensively studied gene in the field of angiogenesis. Despite achieving some advances in mesenchymal stem cell (MSC) therapy in angiogenesis, there are still a certain number of patients who fail to respond to cell therapy. Thus, a novel therapeutic strategy to enhance the angiogenic property of transplanted cells is desirable. This study examined the impact of combined netrin-1 protein and MSC implantation on therapeutic angiogenesis in a rat model of hind limb ischemia. Hind limb ischemic rats (n = 24) were divided randomly into four groups (six rats per group): control group (0.05 mL saline); netrin-1 group (1 μg netrin-1 dissolved in 0.05 mL saline); MSC group (1 × 10(6) MSCs); and netrin-1/MSCs group (1 μg netrin-1 combined with MSCs). Netrin-1 and/or MSCs were injected directly into the muscle of the ischemic limb. Gross appearance of ischemic limb, collateral vessel formation, and vascular endothelial growth factor (VEGF) level were assessed 28 d after treatment. The results showed that pretreatment of MSCs with a recombinant netrin-1 protein markedly augmented the angiographic score and capillary density, improved function of the ischemic limb, and increased levels of VEGF in the plasma and damaged tissues. Further studies assaying the cell migration and network formation suggested that netrin-1 promoted MSC migration and enhanced its ability to participate in tube formation. These results demonstrated that transplantation of MSCs pretreated with netrin-1 protein significantly improved the therapeutic effect of MSCs and, therefore, may provide a novel therapeutic approach for ischemic disease. Copyright © 2011 Elsevier

  1. Pharmacokinetics of Active Components From Guhong Injection in Normal and Pathological Rat Models of Cerebral Ischemia: A Comparative Study

    Directory of Open Access Journals (Sweden)

    Li Yu

    2018-05-01

    Full Text Available Background and Objectives: Guhong Injection (GHI is usually administered for the treatment of stroke in clinics. Aceglutamide and hydroxyl safflower yellow A (HSYA are its key ingredients for brain protective effect. To investigate the pharmacokinetics of aceglutamide and HSYA under pathological and normal conditions, the pharmacokinetic parameters and characteristics of middle cerebral artery occlusion (MCAO and normal rats given the same dosage of GHI were studied compared.Methods: 12 SD rats were divided into two groups, namely, MCAO and normal groups. Both groups were treated with GHI in the same dosage. Plasma samples were collected from the jaw vein at different time points and subsequently tested by high-performance liquid chromatography (HPLC.Results: After administration of GHI, both aceglutamide and HSYA were immediately detected in the plasma. Ninety percent of aceglutamide and HSYA was eliminated within 3 h. For aceglutamide, statistically significant differences in the parameters including AUC(0−t, AUC(0−∞, AUMC(0−t, AUMC(0−∞, Cmax (P < 0.01, and Vz (P < 0.05. Meanwhile, compared with the MCAO group, in the normal group, the values of AUC(0−t, AUMC(0−t, VRT(0−t, and Cmax (P < 0.01 for HSYA were significantly higher, whereas the value of MRT(0−t was significantly lower in the normal group.Conclusions: The in vivo trials based on the different models showed that, the pharmacokinetic behaviors and parameters of aceglutamide and HSYA in GHI were completely different. These results suggest that the pathological damage of ischemia-reperfusion has a significant impact on the pharmacokinetic traits of aceglutamide and HSYA.

  2. Stochastic partial differential equations a modeling, white noise functional approach

    CERN Document Server

    Holden, Helge; Ubøe, Jan; Zhang, Tusheng

    1996-01-01

    This book is based on research that, to a large extent, started around 1990, when a research project on fluid flow in stochastic reservoirs was initiated by a group including some of us with the support of VISTA, a research coopera­ tion between the Norwegian Academy of Science and Letters and Den norske stats oljeselskap A.S. (Statoil). The purpose of the project was to use stochastic partial differential equations (SPDEs) to describe the flow of fluid in a medium where some of the parameters, e.g., the permeability, were stochastic or "noisy". We soon realized that the theory of SPDEs at the time was insufficient to handle such equations. Therefore it became our aim to develop a new mathematically rigorous theory that satisfied the following conditions. 1) The theory should be physically meaningful and realistic, and the corre­ sponding solutions should make sense physically and should be useful in applications. 2) The theory should be general enough to handle many of the interesting SPDEs that occur in r...

  3. Growth modeling of Cryptomeria japonica by partial trunk analysis

    Directory of Open Access Journals (Sweden)

    Vinícius Morais Coutinho

    2017-06-01

    Full Text Available This study aimed to evaluate the growth pattern of Cryptomeria japonica increment (L. F. D. Don. and to describe the probability distribution in stands stablished at the municipality of Rio Negro, Paraná State. Twenty trees were sampled in a 34 years-old stand, with 3 m x 2 m spacing. Wood disks were taken from each tree at 1.3 m above the ground (DBH to perform partial stem analysis. Diameter growth series without bark were used to generate the average cumulative growth curves for DBH (cm, mean annual increment (MAI and current annual increment (CAI. From the increment data, the frequency distribution was evaluated by means of probability density functions (pdfs. The mean annual increment for DBH was 0.78 cm year-1 and the age of intersection of CAI and MAI curves was between the 7th and 8th years. It was found that near 43% of the species increments are concentrated bellow 0.5 cm. The results are useful to define appropriate management strategies for the species for sites similar to the studying regions, defining for example ages of silvicultural intervention, such as thinning.

  4. Globally COnstrained Local Function Approximation via Hierarchical Modelling, a Framework for System Modelling under Partial Information

    DEFF Research Database (Denmark)

    Øjelund, Henrik; Sadegh, Payman

    2000-01-01

    be obtained. This paper presents a new approach for system modelling under partial (global) information (or the so called Gray-box modelling) that seeks to perserve the benefits of the global as well as local methodologies sithin a unified framework. While the proposed technique relies on local approximations......Local function approximations concern fitting low order models to weighted data in neighbourhoods of the points where the approximations are desired. Despite their generality and convenience of use, local models typically suffer, among others, from difficulties arising in physical interpretation...... simultaneously with the (local estimates of) function values. The approach is applied to modelling of a linear time variant dynamic system under prior linear time invariant structure where local regression fails as a result of high dimensionality....

  5. Delayed contrast enhancement imaging of a murine model for ischemia reperfusion with carbon nanotube micro-CT.

    Directory of Open Access Journals (Sweden)

    Laurel M Burk

    Full Text Available We aim to demonstrate the application of free-breathing prospectively gated carbon nanotube (CNT micro-CT by evaluating a myocardial infarction model with a delayed contrast enhancement technique. Evaluation of murine cardiac models using micro-CT imaging has historically been limited by extreme imaging requirements. Newly-developed CNT-based x-ray sources offer precise temporal resolution, allowing elimination of physiological motion through prospective gating. Using free-breathing, cardiac-gated CNT micro-CT, a myocardial infarction model can be studied non-invasively and with high resolution. Myocardial infarction was induced in eight male C57BL/6 mice aged 8-12 weeks. The ischemia reperfusion model was achieved by surgically occluding the LAD artery for 30 minutes followed by 24 hours of reperfusion. Tail vein catheters were placed for contrast administration. Iohexol 300 mgI/mL was administered followed by images obtained in diastole. Iodinated lipid blood pool contrast agent was then administered, followed with images at systole and diastole. Respiratory and cardiac signals were monitored externally and used to gate the scans of free-breathing subjects. Seven control animals were scanned using the same imaging protocol. After imaging, the heart was harvested, cut into 1mm slices and stained with TTC. Post-processing analysis was performed using ITK-Snap and MATLAB. All animals demonstrated obvious delayed contrast enhancement in the left ventricular wall following the Iohexol injection. The blood pool contrast agent revealed significant changes in cardiac function quantified by 3-D volume ejection fractions. All subjects demonstrated areas of myocardial infarct in the LAD distribution on both TTC staining and micro-CT imaging. The CNT micro-CT system aids straightforward, free-breathing, prospectively-gated 3-D murine cardiac imaging. Delayed contrast enhancement allows identification of infarcted myocardium after a myocardial ischemic

  6. [Mechanism of treatment effect of Huanglian-Huangqin herb pairs on cerebral ischemia rats based on metabolomic approach].

    Science.gov (United States)

    Cao, Hui-Ting; Zhu, Hua-Xu; Zhang, Qi-Chun; Guo, Li-Wei

    2017-06-01

    The metabolic effect of Huanglian-Huangqin herb pairs on cerebral ischemia rats was studied by using metabolomic method. The rat model of ischemia reperfusion injury induced by introduction of transient middle cerebral artery occlusion (MCAO) followed by reperfusion. Ultra high performance liquid chromatography-series four pole time of flight mass spectrometry method(UPLC-Q-TOF/MS), Markerlynx software, and principal component analysis and partial least-squares discriminant analysis were used to analyze the different endogenous metabolites among the urine samples of sham rats, cerebral ischemia model rats, Huanglian groups (HL), Huangqin groups (HQ) and Huanglian-Huangqin herb pairs groups (LQ) was achieved, combined with accurate information about the endogenous metabolites level and secondary fragment ions, retrieval and identification of possible biological markers, metabolic pathway which build in MetPA database. The 20 potential biomarkers were found in the urine of rats with cerebral ischemia, which mainly involved in the neurotransmitter regulation, amino acid metabolism, energy metabolism, lipid metabolism and so on. Those metabolic pathways were disturbed in cerebral ischemia model rats, the principal component analysis showed that the normal and cerebral ischemia model is clearly distinguished, and the compound can be given to the normal state of change after HL, HQ, LQ administration. This study index the interpretation of cerebral ischemia rat metabolism group and mechanism, the embodiment of metabonomics can reflect the physiological and metabolic state, which can better reflect the traditional Chinese medicine as a whole view, system view and the features of multi ingredient synergistic or antagonistic effects. Copyright© by the Chinese Pharmaceutical Association.

  7. Partial-order reduction for GPU model checking

    NARCIS (Netherlands)

    Neele, T.S.; Wijs, A.J.; Bošnački, D.; van de Pol, J.C.

    2016-01-01

    Model checking using GPUs has seen increased popularity over the last years. Because GPUs have a limited amount of memory, only small to medium-sized systems can be verified. For on-the-fly explicitstate model checking, we improve memory efficiency by applying partialorder reduction. We propose

  8. Partially linear varying coefficient models stratified by a functional covariate

    KAUST Repository

    Maity, Arnab

    2012-10-01

    We consider the problem of estimation in semiparametric varying coefficient models where the covariate modifying the varying coefficients is functional and is modeled nonparametrically. We develop a kernel-based estimator of the nonparametric component and a profiling estimator of the parametric component of the model and derive their asymptotic properties. Specifically, we show the consistency of the nonparametric functional estimates and derive the asymptotic expansion of the estimates of the parametric component. We illustrate the performance of our methodology using a simulation study and a real data application.

  9. Mathematical analysis of partial differential equations modeling electrostatic MEMS

    CERN Document Server

    Esposito, Pierpaolo; Guo, Yujin

    2010-01-01

    Micro- and nanoelectromechanical systems (MEMS and NEMS), which combine electronics with miniature-size mechanical devices, are essential components of modern technology. It is the mathematical model describing "electrostatically actuated" MEMS that is addressed in this monograph. Even the simplified models that the authors deal with still lead to very interesting second- and fourth-order nonlinear elliptic equations (in the stationary case) and to nonlinear parabolic equations (in the dynamic case). While nonlinear eigenvalue problems-where the stationary MEMS models fit-are a well-developed

  10. [Characteristics of antiischemic and nootropic properties of ademol in a rat model of acute brain ischemia].

    Science.gov (United States)

    Khodakivs'kyĭ, O A

    2013-01-01

    In experiments with the rat model of acute disorder of encephalic circulation (bilateral carotid occlusion) it was found that introduction of derivate of adamantan 1-adamantiloxy-3-morfolino-2 propanol (under conventional name ademol) in the dose 2 mg/kg intraabdominal in treatment regimen (in an hour after reconstruction of insult and further 1 time every 24 hours during 21 days) was accompanied by a recovery of mnemotropic properties and is more effective than cytikolin, resulting in a decreased lethality and neurological deficiency in acute and recovery periods of insults. The data received proved the usefulness of development of ademol based cerebroprotective remedy.

  11. Cardioprotection by minocycline in a rabbit model of ischemia/reperfusion injury : Detection of cell death by in vivo (111)In-GSAO SPECT

    NARCIS (Netherlands)

    Yamaki, Takayoshi; de Haas, Hans J; Tahara, Nobuhiro; Petrov, Artiom; Mohar, Dilbahar; Haider, Nezam; Zhou, Jun; Tahara, Atsuko; Takeishi, Yasuchika; Boersma, Hendrikus H; Scarabelli, Tiziano; Kini, Annapoorna; Strauss, H William; Narula, Jagat

    BACKGROUND: Preclinical studies indicate that minocycline protects against myocardial ischemia/reperfusion injury. In these studies, minocycline was administered before ischemia, which can rarely occur in clinical practice. The current study aimed to evaluate cardioprotection by minocycline

  12. Active Compounds of Rhubarb Root and Rhizome in Animal Model Experiments of Focal Cerebral Ischemia

    Directory of Open Access Journals (Sweden)

    Ai-ju Liu

    2015-01-01

    Full Text Available Rhubarb root and rhizome (RRR has been clinically used for stroke at least 2000 years and is still used in modern times in both China and elsewhere worldwide. The objective of present study was to evaluate the efficacy of active compounds of RRR (ACRRR for experimental ischemic stroke. Studies of ACRRR in animal models of ischemic stroke were identified from 5 databases until April 2014. Study quality for each included article was evaluated according to the CAMARADES 10-item checklist. Outcome measures were neurological deficit score and infarct size. All the data were analyzed using RevMan 5.1 software. As a result, 20 studies were identified describing procedures involving 577 animals. The quality score of studies ranges from 2 to 6, and the median was 3.4. Six studies showed significant effects of ACRRR for improving infarct size compared with model group (P<0.01. Six studies indicated significant effects of ACRRR for improving the neurological deficit scores according to Zea longa criterion or eight-point criterion (P<0.01. In conclusion, these findings demonstrated a possible efficacy of ACRRR that have potential neuroprotective effect for experimental ischemic stroke. However, these apparently positive findings should be interpreted with caution because of the methodological flaws.

  13. Emulating facial biomechanics using multivariate partial least squares surrogate models

    OpenAIRE

    Martens, Harald; Wu, Tim; Hunter, Peter; Mithraratne, Kumar

    2014-01-01

    This is the author’s final, accepted and refereed manuscript to the article. Locked until 2015-05-06 A detailed biomechanical model of the human face driven by a network of muscles is a useful tool in relating the muscle activities to facial deformations. However, lengthy computational times often hinder its applications in practical settings. The objective of this study is to replace precise but computationally demanding biomechanical model by a much faster multivariate meta-mode...

  14. the Modeling of Hydraulic Jump Generated Partially on Sloping Apron

    Directory of Open Access Journals (Sweden)

    Shaker Abdulatif Jalil

    2017-12-01

    Full Text Available Modeling aims to characterize system behavior and achieve simulation close as possible of the reality. The rapid energy exchange in supercritical flow to generate quiet or subcritical flow in hydraulic jump phenomenon is important in design of hydraulic structures. Experimental and numerical modeling is done on type B hydraulic jump which starts first on sloping bed and its end on horizontal bed.  Four different apron slopes are used, for each one of these slopes the jump is generated on different locations by controlling the tail water depth.  Modelling validation is based on 120 experimental runs which they show that there is reliability. The air volume fraction which creates in through hydraulic jump varied between 0.18 and 0.28. While the energy exchanges process take place within 6.6, 6.1, 5.8, 5.5 of the average relative jump height for apron slopes of 0.18, 0.14, 0.10, 0.07 respectively. Within the limitations of this study, mathematical prediction model for relative hydraulic jump height is suggested.The model having an acceptable coefficient of determination.

  15. A discrete model of a modified Burgers' partial differential equation

    Science.gov (United States)

    Mickens, R. E.; Shoosmith, J. N.

    1990-01-01

    A new finite-difference scheme is constructed for a modified Burger's equation. Three special cases of the equation are considered, and the 'exact' difference schemes for the space- and time-independent forms of the equation are presented, along with the diffusion-free case of Burger's equation modeled by a difference equation. The desired difference scheme is then obtained by imposing on any difference model of the initial equation the requirement that, in the appropriate limits, its difference scheme must reduce the results of the obtained equations.

  16. Models & Searches of CPT Violation: a personal, very partial, list

    Science.gov (United States)

    Mavromatos, Nick E.

    2018-01-01

    In this talk, first I motivate theoretically, and then I review the phenomenology of, some models entailing CPT Violation (CPTV). The latter is argued to be responsible for the observed matter-antimatter asymmetry in the Cosmos, and may owe its origin to either Lorentz-violating background geometries, whose effects are strong in early epochs of the Universe but very weak today, being temperature dependent in general, or to an ill-defined CPT generator in some quantum gravity models entailing decoherence of quantum matter as a result of quantum degrees of freedom in the gravity sector that are inaccessible to the low-energy observers. In particular, for the latter category of CPTV, I argue that entangled states of neutral mesons (Kaons or B-systems), of central relevance to KLOE-2 experiment, can provide smoking-gun sensitive tests or even falsify some of these models. If CPT is ill-defined one may also encounter violations of the spin-statistics theorem, with possible consequences for the Pauli Exclusion Principle, which I only briefly touch upon.

  17. Models & Searches of CPT Violation: a personal, very partial, list

    Directory of Open Access Journals (Sweden)

    Mavromatos Nick E.

    2018-01-01

    Full Text Available In this talk, first I motivate theoretically, and then I review the phenomenology of, some models entailing CPT Violation (CPTV. The latter is argued to be responsible for the observed matter-antimatter asymmetry in the Cosmos, and may owe its origin to either Lorentz-violating background geometries, whose effects are strong in early epochs of the Universe but very weak today, being temperature dependent in general, or to an ill-defined CPT generator in some quantum gravity models entailing decoherence of quantum matter as a result of quantum degrees of freedom in the gravity sector that are inaccessible to the low-energy observers. In particular, for the latter category of CPTV, I argue that entangled states of neutral mesons (Kaons or B-systems, of central relevance to KLOE-2 experiment, can provide smoking-gun sensitive tests or even falsify some of these models. If CPT is ill-defined one may also encounter violations of the spin-statistics theorem, with possible consequences for the Pauli Exclusion Principle, which I only briefly touch upon.

  18. Partially collisional model of the Titan hydrogen torus

    International Nuclear Information System (INIS)

    Hilton, D.A.

    1987-01-01

    A numerical model was developed for atomic hydrogen densities in the Titan hydrogen torus. The effects of occasional collisions were included in order to accurately simulate physical conditions inferred from the Voyager 1 and 2 Ultraviolet Spectrometer (UVS) results of Broadfoot et al. (1981) and Sandel et al. (1982). The model employed Lagrangian perturbation of orbital elements of hydrogen atoms launched from Titan and Monte Carlo simulation of collisions and loss mechanisms. The torus is found to be azimuthally symmetric with the density sharply peaked at Titan's orbit, and decreasing rapidly in the outward and perpendicular directions and more gradually inward from 17 to 5 R/sub s/. The energetic hydrogen atoms from Saturn's upper atmosphere, first predicted by Shemansky and Smith (1982), were also investigated. Collisions of these Saturnian atoms with the torus population do not contribute to the torus density, and will lead to a net loss of torus atoms if their launch speeds from Saturn extend above 40 km/sec. The Saturnian atoms produce a corona which was modeled using the theory of Chamberlain (1963)

  19. Forced treadmill exercise can induce stress and increase neuronal damage in a mouse model of global cerebral ischemia

    Directory of Open Access Journals (Sweden)

    Martina Svensson

    2016-12-01

    Full Text Available Physical exercise is known to be a beneficial factor by increasing the cellular stress tolerance. In ischemic stroke, physical exercise is suggested to both limit the brain injury and facilitate behavioral recovery. In this study we investigated the effect of physical exercise on brain damage following global cerebral ischemia in mice. We aimed to study the effects of 4.5 weeks of forced treadmill running prior to ischemia on neuronal damage, neuroinflammation and its effect on general stress by measuring corticosterone in feces. We subjected C57bl/6 mice (n = 63 to either treadmill running or a sedentary program prior to induction of global ischemia. Anxious, depressive, and cognitive behaviors were analyzed. Stress levels were analyzed using a corticosterone ELISA. Inflammatory and neurological outcomes were analyzed using immunohistochemistry, multiplex electrochemoluminescence ELISA and Western blot. To our surprise, we found that forced treadmill running induced a stress response, with increased anxiety in the Open Field test and increased levels of corticosterone. In accordance, mice subjected to forced exercise prior to ischemia developed larger neuronal damage in the hippocampus and showed higher cytokine levels in the brain and blood compared to non-exercised mice. The extent of neuronal damage correlated with increased corticosterone levels. To compare forced treadmill with voluntary wheel running, we used a different set of mice that exercised freely on running wheels. These mice did not show any anxiety or increased corticosterone levels. Altogether, our results indicate that exercise pre-conditioning may not be beneficial if the animals are forced to run as it can induce a detrimental stress response.

  20. Electrophysiological, haemodynamic, and mitochondrial alterations induced by levobupivacaine during myocardial ischemia in a pig model: protection by lipid emulsions?

    Science.gov (United States)

    Mamou, Zahida; Descotes, Jacques; Chevalier, Philippe; Bui-Xuan, Bernard; Romestaing, Caroline; Timour, Quadiri

    2015-10-01

    Accidental intravascular or high-dose injection of local anesthetics (LA) can result in serious, potentially life-threatening complications. Indeed, adequate supportive measures and the administration of lipid emulsions are required in such complications. The study's objectives were threefold: (i) evaluate the myocardial toxicity of levobupivacaine when administered intravenously; (ii) investigate levobupivacaine toxicity on cardiomyocytes mitochondrial functions and cellular structure; (iii) assess the protective effects of a lipid emulsion in the presence or absence of myocardial ischemia. Domestic pigs randomized into two groups of 24 animals each, with either preserved coronary circulation or experimental myocardial ischemia. Six animals from each group received either: (i) single IV injection of saline, (ii) lipid emulsion (Intralipid(®) ), (iii) levobupivacaine, (iv) combination levobupivacaine-Intralipid(®) . Serially measured endpoints included: heart rate, duration of the monophasic action potentials (dMAP), mean arterial pressure, and peak of the time derivative of left ventricular pressure (LV dP/dtmax ). In addition, the following cardiomyocytes mitochondrial functions were measured: reactive oxygen species (ROS) production, oxidative phosphorylation, and calcium retention capacity (CRC) as well as the consequences of ROS production on lipids, proteins, and DNA. IV injection of levobupivacaine induced sinus bradycardia and reduced dMAP and LV dP/dtmax . At the mitochondrial level, oxygen consumption and CRC were decreased. In contrast, ROS production was increased leading to enhanced lipid peroxidation and structural alterations of proteins and DNA. Myocardial ischemia was associated with global worsening of all changes. Intralipid(®) quickly improved haemodynamics. However, beneficial effects of Intralipid(®) were less clear after myocardial ischemia. © 2015 Société Française de Pharmacologie et de Thérapeutique.

  1. Magnetic Resonance Imaging Allows the Evaluation of Tissue Damage and Regeneration in a Mouse Model of Critical Limb Ischemia.

    Directory of Open Access Journals (Sweden)

    Germana Zaccagnini

    Full Text Available Magnetic resonance imaging (MRI provides non-invasive, repetitive measures in the same individual, allowing the study of a physio-pathological event over time. In this study, we tested the performance of 7 Tesla multi-parametric MRI to monitor the dynamic changes of mouse skeletal muscle injury and regeneration upon acute ischemia induced by femoral artery dissection. T2-mapping (T2 relaxation time, diffusion-tensor imaging (Fractional Anisotropy and perfusion by Dynamic Contrast-Enhanced MRI (K-trans were measured and imaging results were correlated with histological morphometric analysis in both Gastrocnemius and Tibialis anterior muscles. We found that tissue damage positively correlated with T2-relaxation time, while myofiber regeneration and capillary density positively correlated with Fractional Anisotropy. Interestingly, K-trans positively correlated with capillary density. Accordingly, repeated MRI measurements between day 1 and day 28 after surgery in ischemic muscles showed that: 1 T2-relaxation time rapidly increased upon ischemia and then gradually declined, returning almost to basal level in the last phases of the regeneration process; 2 Fractional Anisotropy dropped upon ischemic damage induction and then recovered along with muscle regeneration and neoangiogenesis; 3 K-trans reached a minimum upon ischemia, then progressively recovered. Overall, Gastrocnemius and Tibialis anterior muscles displayed similar patterns of MRI parameters dynamic, with more marked responses and less variability in Tibialis anterior. We conclude that MRI provides quantitative information about both tissue damage after ischemia and the subsequent vascular and muscle regeneration, accounting for the differences between subjects and, within the same individual, between different muscles.

  2. Magnetic Resonance Imaging Allows the Evaluation of Tissue Damage and Regeneration in a Mouse Model of Critical Limb Ischemia.

    Science.gov (United States)

    Zaccagnini, Germana; Palmisano, Anna; Canu, Tamara; Maimone, Biagina; Lo Russo, Francesco M; Ambrogi, Federico; Gaetano, Carlo; De Cobelli, Francesco; Del Maschio, Alessandro; Esposito, Antonio; Martelli, Fabio

    2015-01-01

    Magnetic resonance imaging (MRI) provides non-invasive, repetitive measures in the same individual, allowing the study of a physio-pathological event over time. In this study, we tested the performance of 7 Tesla multi-parametric MRI to monitor the dynamic changes of mouse skeletal muscle injury and regeneration upon acute ischemia induced by femoral artery dissection. T2-mapping (T2 relaxation time), diffusion-tensor imaging (Fractional Anisotropy) and perfusion by Dynamic Contrast-Enhanced MRI (K-trans) were measured and imaging results were correlated with histological morphometric analysis in both Gastrocnemius and Tibialis anterior muscles. We found that tissue damage positively correlated with T2-relaxation time, while myofiber regeneration and capillary density positively correlated with Fractional Anisotropy. Interestingly, K-trans positively correlated with capillary density. Accordingly, repeated MRI measurements between day 1 and day 28 after surgery in ischemic muscles showed that: 1) T2-relaxation time rapidly increased upon ischemia and then gradually declined, returning almost to basal level in the last phases of the regeneration process; 2) Fractional Anisotropy dropped upon ischemic damage induction and then recovered along with muscle regeneration and neoangiogenesis; 3) K-trans reached a minimum upon ischemia, then progressively recovered. Overall, Gastrocnemius and Tibialis anterior muscles displayed similar patterns of MRI parameters dynamic, with more marked responses and less variability in Tibialis anterior. We conclude that MRI provides quantitative information about both tissue damage after ischemia and the subsequent vascular and muscle regeneration, accounting for the differences between subjects and, within the same individual, between different muscles.

  3. Rat Experimental Model of Myocardial Ischemia/Reperfusion Injury: An Ethical Approach to Set up the Analgesic Management of Acute Post-Surgical Pain

    Science.gov (United States)

    Ciuffreda, Maria Chiara; Tolva, Valerio; Casana, Renato; Gnecchi, Massimiliano; Vanoli, Emilio; Spazzolini, Carla; Roughan, John; Calvillo, Laura

    2014-01-01

    Rationale During the past 30 years, myocardial ischemia/reperfusion injury in rodents became one of the most commonly used model in cardiovascular research. Appropriate pain-prevention appears critical since it may influence the outcome and the results obtained with this model. However, there are no proper guidelines for pain management in rats undergoing thoracic surgery. Accordingly, we evaluated three analgesic regimens in cardiac ischemia/reperfusion injury. This study was strongly focused on 3R’s ethic principles, in particular the principle of Reduction. Methods Rats undergoing surgery were treated with pre-surgical tramadol (45 mg/kg intra-peritoneal), or carprofen (5 mg/kg sub-cutaneous), or with pre-surgical administration of carprofen followed by 2 post-surgery tramadol injections (multi-modal group). We assessed behavioral signs of pain and made a subjective evaluation of stress and suffering one and two hours after surgery. Results Multi-modal treatment significantly reduced the number of signs of pain compared to carprofen alone at both the first hour (61±42 vs 123±47; pCarprofen alone was more effective at the second hour post-surgery when signs of pain reduced to 74±24 from 113±40 in the first hour (pcarprofen and tramadol groups, respectively (pcarprofen and tramadol was more effective in preventing pain during the second hour after surgery compared with both tramadol or carprofen. Our results suggest that the combination of carprofen and tramadol represent the best therapy to prevent animal pain after myocardial ischemia/reperfusion. We obtained our results accordingly with the ethical principle of Reduction. PMID:24756074

  4. Electroacupuncture modulates stromal cell-derived factor-1α expression and mobilization of bone marrow endothelial progenitor cells in focal cerebral ischemia/reperfusion model rats.

    Science.gov (United States)

    Xie, Chenchen; Gao, Xiang; Luo, Yong; Pang, Yueshan; Li, Man

    2016-10-01

    Stromal cell-derived factor-1α(SDF-1α) plays a crucial role in regulating the mobilization, migration and homing of endothelial progenitor cells(EPCs). Electroacupuncture(EA), a modern version of Traditional Chinese Medicine, can improve neurological recovery and angiogenesis in cerebral ischemic area. This study aimed to investigate the effects of electroacupuncture(EA) on the mobilization and migration of bone marrow EPCs and neurological functional recovery in rats model after focal cerebral ischemia/reperfusion and the potentially involved mechanisms. Sprague-Dawley rats received filament occlusion of the right middle cerebral artery for 2h followed by reperfusion for 12h, 1d, 2d, 3d, 7d respectively. Rats were randomly divided into sham group, model group and EA group. After 2h of the reperfusion, EA was given at the "Baihui" (GV 20)/Siguan ("Hegu" (LI 4)/"Taichong" (LR 3)) acupoints in the EA group. Modified neurological severity score (mNSS) was used to assess the neurological functional recovery. EPCs number and SDF-1α level in bone marrow(BM) and peripheral blood(PB) were detected by using fluorescence-activated cell sorting (FACS) analysis and quantitative real time polymerase chain reaction (qRT-PCR) respectively. An mNSS test showed that EA treatment significantly improved the neurological functional outcome. EPCs number in PB and BM were obviously increased in the EA group. After cerebral ischemia, the SDF-1α level was decreased in BM while it was increased in PB, which implied a gradient of SDF-1α among BM and PB after ischemia. It suggested that the forming of SDF-1α concentration gradient can induce the mobilization and homing of EPCs. Eletroacupuncture as a treatment can accelerate and increase the forming of SDF-1α concentration gradient to further induce the mobilization of EPCs and angiogenesis in ischemic brain and improve the neurological function recovery. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Protective effects of tempol in an experimental ovarian ischemia-reperfusion injury model in female Wistar albino rats.

    Science.gov (United States)

    Pınar, Neslihan; Soylu Karapınar, Oya; Özcan, Oğuzhan; Atik Doğan, Esin; Bayraktar, Suphi

    2017-07-01

    The aim of this study was to investigate the antioxidant effects of tempol on ovarian ischemia-reperfusion (I/R) injury in rats. Forty female Wistar albino rats were randomly divided into 5 groups: Group I, sham; Group II, ischemia (I); Group III, I/R; Group IV, I/R + tempol 30 mg/kg i.p; Group V, I/R + tempol 50 mg/kg i.p. Oxidative stress index (OSI) was significantly higher in the ischemia group and the I/R group than in the sham group. Catalase levels were significantly lower in the I/R group than in the I/R + tempol 30 mg/kg i.p. and the I/R + tempol 50 mg/kg i.p. groups. Glutathione peroxidase levels were lower in the I/R group than in the I/R + tempol 30 mg/kg i.p. and the I/R + tempol 50 mg/kg i.p. groups. MDA levels were significantly lower in the I/R + tempol 30 mg/kg i.p. group and the I/R + tempol 50 mg/kg i.p. group than in the I/R group. The levels of the histopathological parameters were significantly decreased in the I/R + tempol 50 mg/kg i.p. group compared with the I/R group. Tempol can be used for reducing ovarian I/R injury.

  6. Soft sensor modelling by time difference, recursive partial least squares and adaptive model updating

    International Nuclear Information System (INIS)

    Fu, Y; Xu, O; Yang, W; Zhou, L; Wang, J

    2017-01-01

    To investigate time-variant and nonlinear characteristics in industrial processes, a soft sensor modelling method based on time difference, moving-window recursive partial least square (PLS) and adaptive model updating is proposed. In this method, time difference values of input and output variables are used as training samples to construct the model, which can reduce the effects of the nonlinear characteristic on modelling accuracy and retain the advantages of recursive PLS algorithm. To solve the high updating frequency of the model, a confidence value is introduced, which can be updated adaptively according to the results of the model performance assessment. Once the confidence value is updated, the model can be updated. The proposed method has been used to predict the 4-carboxy-benz-aldehyde (CBA) content in the purified terephthalic acid (PTA) oxidation reaction process. The results show that the proposed soft sensor modelling method can reduce computation effectively, improve prediction accuracy by making use of process information and reflect the process characteristics accurately. (paper)

  7. Low-intensity pulsed ultrasound induces angiogenesis and ameliorates left ventricular dysfunction in a porcine model of chronic myocardial ischemia.

    Directory of Open Access Journals (Sweden)

    Kenichiro Hanawa

    Full Text Available Although a significant progress has been made in the management of ischemic heart disease (IHD, the number of severe IHD patients is increasing. Thus, it is crucial to develop new, non-invasive therapeutic strategies. In the present study, we aimed to develop low-intensity pulsed ultrasound (LIPUS therapy for the treatment of IHD.We first confirmed that in cultured human endothelial cells, LIPUS significantly up-regulated mRNA expression of vascular endothelial growth factor (VEGF with a peak at 32-cycle (P<0.05. Then, we examined the in vivo effects of LIPUS in a porcine model of chronic myocardial ischemia with reduced left ventricular ejection fraction (LVEF (n = 28. The heart was treated with either sham (n = 14 or LIPUS (32-cycle with 193 mW/cm2 for 20 min, n = 14 at 3 different short axis levels. Four weeks after the treatment, LVEF was significantly improved in the LIPUS group (46±4 to 57±5%, P<0.05 without any adverse effects, whereas it remained unchanged in the sham group (46±5 to 47±6%, P = 0.33. Capillary density in the ischemic region was significantly increased in the LIPUS group compared with the control group (1084±175 vs. 858±151/mm2, P<0.05. Regional myocardial blood flow was also significantly improved in the LIPUS group (0.78±0.2 to 1.39±0.4 ml/min/g, P<0.05, but not in the control group (0.84±0.3 to 0.97±0.4 ml/min/g. Western blot analysis showed that VEGF, eNOS and bFGF were all significantly up-regulated only in the LIPUS group.These results suggest that the LIPUS therapy is promising as a new, non-invasive therapy for IHD.

  8. A simple procedure to model water level fluctuations in partially inundated wetlands

    NARCIS (Netherlands)

    Spieksma, JFM; Schouwenaars, JM

    When modelling groundwater behaviour in wetlands, there are specific problems related to the presence of open water in small-sized mosaic patterns. A simple quasi two-dimensional model to predict water level fluctuations in partially inundated wetlands is presented. In this model, the ratio between

  9. Calculus for cognitive scientists partial differential equation models

    CERN Document Server

    Peterson, James K

    2016-01-01

    This book shows cognitive scientists in training how mathematics, computer science and science can be usefully and seamlessly intertwined. It is a follow-up to the first two volumes on mathematics for cognitive scientists, and includes the mathematics and computational tools needed to understand how to compute the terms in the Fourier series expansions that solve the cable equation. The latter is derived from first principles by going back to cellular biology and the relevant biophysics.  A detailed discussion of ion movement through cellular membranes, and an explanation of how the equations that govern such ion movement leading to the standard transient cable equation are included. There are also solutions for the cable model using separation of variables, as well an explanation of why Fourier series converge and a description of the implementation of MatLab tools to compute the solutions. Finally, the standard Hodgkin - Huxley model is developed for an excitable neuron and is solved using MatLab.

  10. Quantitative analysis of CT brain images: a statistical model incorporating partial volume and beam hardening effects

    International Nuclear Information System (INIS)

    McLoughlin, R.F.; Ryan, M.V.; Heuston, P.M.; McCoy, C.T.; Masterson, J.B.

    1992-01-01

    The purpose of this study was to construct and evaluate a statistical model for the quantitative analysis of computed tomographic brain images. Data were derived from standard sections in 34 normal studies. A model representing the intercranial pure tissue and partial volume areas, with allowance for beam hardening, was developed. The average percentage error in estimation of areas, derived from phantom tests using the model, was 28.47%. We conclude that our model is not sufficiently accurate to be of clinical use, even though allowance was made for partial volume and beam hardening effects. (author)

  11. Error propagation of partial least squares for parameters optimization in NIR modeling.

    Science.gov (United States)

    Du, Chenzhao; Dai, Shengyun; Qiao, Yanjiang; Wu, Zhisheng

    2018-03-05

    A novel methodology is proposed to determine the error propagation of partial least-square (PLS) for parameters optimization in near-infrared (NIR) modeling. The parameters include spectral pretreatment, latent variables and variable selection. In this paper, an open source dataset (corn) and a complicated dataset (Gardenia) were used to establish PLS models under different modeling parameters. And error propagation of modeling parameters for water quantity in corn and geniposide quantity in Gardenia were presented by both type І and type II error. For example, when variable importance in the projection (VIP), interval partial least square (iPLS) and backward interval partial least square (BiPLS) variable selection algorithms were used for geniposide in Gardenia, compared with synergy interval partial least squares (SiPLS), the error weight varied from 5% to 65%, 55% and 15%. The results demonstrated how and what extent the different modeling parameters affect error propagation of PLS for parameters optimization in NIR modeling. The larger the error weight, the worse the model. Finally, our trials finished a powerful process in developing robust PLS models for corn and Gardenia under the optimal modeling parameters. Furthermore, it could provide a significant guidance for the selection of modeling parameters of other multivariate calibration models. Copyright © 2017. Published by Elsevier B.V.

  12. Error propagation of partial least squares for parameters optimization in NIR modeling

    Science.gov (United States)

    Du, Chenzhao; Dai, Shengyun; Qiao, Yanjiang; Wu, Zhisheng

    2018-03-01

    A novel methodology is proposed to determine the error propagation of partial least-square (PLS) for parameters optimization in near-infrared (NIR) modeling. The parameters include spectral pretreatment, latent variables and variable selection. In this paper, an open source dataset (corn) and a complicated dataset (Gardenia) were used to establish PLS models under different modeling parameters. And error propagation of modeling parameters for water quantity in corn and geniposide quantity in Gardenia were presented by both type І and type II error. For example, when variable importance in the projection (VIP), interval partial least square (iPLS) and backward interval partial least square (BiPLS) variable selection algorithms were used for geniposide in Gardenia, compared with synergy interval partial least squares (SiPLS), the error weight varied from 5% to 65%, 55% and 15%. The results demonstrated how and what extent the different modeling parameters affect error propagation of PLS for parameters optimization in NIR modeling. The larger the error weight, the worse the model. Finally, our trials finished a powerful process in developing robust PLS models for corn and Gardenia under the optimal modeling parameters. Furthermore, it could provide a significant guidance for the selection of modeling parameters of other multivariate calibration models.

  13. Various verifying tests using full size partial models of PCCV

    International Nuclear Information System (INIS)

    Nagata, Kaoru; Fukihara, Masaaki; Takemoto, Yasushi.

    1987-01-01

    The prestressed concrete containment vessel (PCCV) for Tsuruga No.2 plant of Japan Atomic Power Co. was adopted for the first time in Japan, and the necessity of experimental verification was pointed out about a number of items in the design and construction. In this report, the various tests carried out with full size models are described. The tendon system adopted for this PCCV is BBRV type, in which PC wires are bundled in parallel to make cables, and involves many matters inexperienced in Japan, such as the stretching capacity is as large as 1000 t class, the longest cable is 160 m, and it is the unbonded system of injecting rust inhibitor. It was demanded to confirm by testing the propriety of the small coefficient of friction at the time of stretching tendons. For the tests, the materials, equipment and their size were prepared all as those for actual works. The test works became the rehearsal of the actual prestressing works. Besides, by utilizing these full size test beds, the workability test on concrete at the time of their construction, the confirmation test on tendon strength and the safety of concrete at fixing part at the time of friction test, thereafter, greasing test, the simulation test of in-service inspection, and the thermal loading test on liners were carried out. The results of these tests are briefly reported. (Kako, I.)

  14. A new Bayesian model applied to cytogenetic partial body irradiation estimation

    International Nuclear Information System (INIS)

    Higueras, Manuel; Puig, Pedro; Ainsbury, Elizabeth A.; Vinnikov, Volodymyr A.; Rothkamm, Kai

    2016-01-01

    A new zero-inflated Poisson model is introduced for the estimation of partial body irradiation dose and fraction of body irradiated. The Bayes factors are introduced as tools to help determine whether a data set of chromosomal aberrations obtained from a blood sample reflects partial or whole body irradiation. Two examples of simulated cytogenetic radiation exposure data are presented to demonstrate the usefulness of this methodology in cytogenetic biological dosimetry. (authors)

  15. Partially nested designs in psychotherapy trials: A review of modeling developments.

    Science.gov (United States)

    Sterba, Sonya K

    2017-07-01

    Individually-randomized psychotherapy trials are often partially nested. For instance, individuals assigned to a treatment arm may be clustered into therapy groups for purposes of treatment administration, whereas individuals assigned to a wait-list control are unclustered. The past several years have seen rapid expansion and investigation of methods for analyzing partially nested data. Yet partial nesting often remains ignored in psychotherapy trials. This review integrates and disseminates developments in the analysis of partially nested data that are particularly relevant for psychotherapy researchers. First, we differentiate among alternative partially nested designs. Then, we present adaptations of multilevel model specifications that accommodate each design. Next, we address how moderation by treatment as well as mediation of the treatment effect can be investigated in partially nested designs. Model fitting results, annotated software syntax, and illustrative data sets are provided and key methodological issues are discussed. We emphasize that cluster-level variability in the treatment arm need not be considered a nuisance; it can be modeled to yield insights about the treatment process.

  16. The Component Slope Linear Model for Calculating Intensive Partial Molar Properties: Application to Waste Glasses

    International Nuclear Information System (INIS)

    Reynolds, Jacob G.

    2013-01-01

    Partial molar properties are the changes occurring when the fraction of one component is varied while the fractions of all other component mole fractions change proportionally. They have many practical and theoretical applications in chemical thermodynamics. Partial molar properties of chemical mixtures are difficult to measure because the component mole fractions must sum to one, so a change in fraction of one component must be offset with a change in one or more other components. Given that more than one component fraction is changing at a time, it is difficult to assign a change in measured response to a change in a single component. In this study, the Component Slope Linear Model (CSLM), a model previously published in the statistics literature, is shown to have coefficients that correspond to the intensive partial molar properties. If a measured property is plotted against the mole fraction of a component while keeping the proportions of all other components constant, the slope at any given point on a graph of this curve is the partial molar property for that constituent. Actually plotting this graph has been used to determine partial molar properties for many years. The CSLM directly includes this slope in a model that predicts properties as a function of the component mole fractions. This model is demonstrated by applying it to the constant pressure heat capacity data from the NaOH-NaAl(OH 4 H 2 O system, a system that simplifies Hanford nuclear waste. The partial molar properties of H 2 O, NaOH, and NaAl(OH) 4 are determined. The equivalence of the CSLM and the graphical method is verified by comparing results detennined by the two methods. The CSLM model has been previously used to predict the liquidus temperature of spinel crystals precipitated from Hanford waste glass. Those model coefficients are re-interpreted here as the partial molar spinel liquidus temperature of the glass components

  17. A partial test of a hospital behavioral model.

    Science.gov (United States)

    Hornbrook, M C; Goldfarb, M G

    1983-01-01

    The influence of hospital and community characteristics on the behavior of five dimensions of hospital output is examined in this article. These dimensions are the level of emergency stand-by capacity, total admissions, the diagnosis-mix of admissions and the hospital's 'style of practice' with regard to ancillary services and length of stay. A simultaneous equations model is estimated with data from a sample of 63 New England short-term general hospitals for 1970. The findings suggest that various types of short-term general hospitals have distinctive preferences for emergency capacity, volume, case mix and style of practice, and that style of practice may be more appropriately viewed as a rate of resource use per day. Specific findings of interest include the positive interdependence between protection against running out of emergency beds and length of stay, and between length of stay and ancillary service use. Hospitals that admit greater numbers of patients tend to treat more severely ill patients, and sicker patients tend to go to larger hospitals. Hospitals that provide more ancillary services tend to attract the more acutely ill patients. Relationships among other elements of the hospital's utility function represent trade-offs, i.e. substitution, in a constrained world. Among the exogenous factors, patient preferences and ability to pay have strong associations with the types of care provided by hospitals. Highly educated, high income communities, for example, tend to prefer risk averse, service intensive hospital output. Teaching hospitals are shown to prefer higher protection levels, service-intensive patterns of care, and higher admissions levels. Self-paying patients tend to be admitted for more discretionary types of diagnoses and to receive longer diagnosis-specific lengths of stay. A relatively greater supply of physician specialists in the market area is associated with increased use of ancillary services in the hospital. If replicated, these

  18. Edaravone, A Free Radical Scavenger, Ameliorates Early-Phase Ischemia/Reperfusion Injury and Increases Hepatocyte Proliferation in A Pig Hepatectomy Model

    Directory of Open Access Journals (Sweden)

    Mitsugi Shimoda

    2012-06-01

    Full Text Available Background: The effects of Edaravone (Edr on hepatic ischemia-reperfusion (I/R injury and liver regeneration were examined in a pig hepatectomy model. Methods: One hour of ischemia was induced by occluding the vessels and the bile duct of the right and median lobes. About a 40% left hepatectomy was performed after reperfusion. Six animals received Edr (3 mg/kg/h intravenously and six control animals received saline just before reperfusion. Remnant liver volume, hemodynamics, and levels of AST, ALT, LDH, and LA were compared between the groups. Expression of TGF-beta1 and IL-6 mRNA in hepatic tissues was examined using RT-PCR. Apoptosis and cell proliferation were demonstrated by TUNEL and Ki-67 staining, respectively. Results: Serum AST, LDH, and LA levels were significantly lower at 3 hours and 1 week after perfusion in animals that had received Edr. In the Edr group, hepatic tissues showed a greater tendency for the expression of TGF-beta1 mRNA to be inhibited at 1 week, although the difference was not significant. Also at 1 week in the Edr group, TUNEL-positive cells in the hepatic sinusoidal endothelium were significantly fewer, and Ki-67-positive cells were significantly more numerous. Conclusion: We conclude that Edr reduces hepatic injury and supports tissue regeneration after I/R injury in this pig model. [Arch Clin Exp Surg 2012; 1(3.000: 142-150

  19. A chiral quark model for meson electroproduction in the S11 partial wave

    International Nuclear Information System (INIS)

    Golli, B.; Sirca, S.

    2011-01-01

    We calculate the meson scattering and electroproduction amplitudes in the S11 partial wave in a coupled-channel approach that incorporates quasi-bound quark-model states. Using the quark wave functions and the quark-meson interaction from the Cloudy Bag Model, we obtain a good overall agreement with the available experimental results for the partial widths of the N(1535) and the N(1650) resonances as well as for the pion, eta and kaon electroproduction amplitudes. Our model is consistent with the N(1535) resonance being dominantly a genuine three-quark state rather than a quasi-bound state of mesons and baryons. (orig.)

  20. Head-to-head comparison of dipyridamole, dobutamine and pacing stress echocardiography for the detection of myocardial ischemia in an animal model of coronary artery stenosis

    Directory of Open Access Journals (Sweden)

    A. Schmidt

    2001-07-01

    Full Text Available To compare the sensitivity of dipyridamole, dobutamine and pacing stress echocardiography for the detection of myocardial ischemia we produced a physiologically significant stenosis in the left circumflex artery of 14 open-chest dogs (range: 50 to 89% reduction in luminal diameter. In each study, dobutamine (5 to 40 µg kg-1 min-1 in 3-min stages and pacing (20 bpm increments, each 2 min, up to 260 bpm were performed randomly, and then followed by dipyridamole (up to 0.84 mg/kg over 10 min. The positivity of stress echocardiography tests was quantitatively determined by a significant (P<0.05 reduction of or failure to increase absolute and percent systolic wall thickening in the stenotic artery supplied wall, as compared to the opposite wall (areas related to the left anterior descending artery. Systolic and diastolic frozen images were analyzed off-line by two blinded observers in the control and stress conditions. The results showed that 1 the sensitivity of dobutamine, dipyridamole and pacing stress tests was 57, 57 and 36%, respectively; 2 in animals with positive tests, the mean percent change of wall thickening in left ventricular ischemic segments was larger in the pacing (-19 ± 11% and dipyridamole (-18 ± 16% tests as compared to dobutamine (-9 ± 6% (P = 0.05, but a similar mean reduction of wall thickening was observed when this variable was normalized to a control left ventricular segment (area related to the left anterior descending artery (pacing: -16 ± 7%; dipyridamole: -25 ± 16%; dobutamine: -26 ± 10%; not significant, and 3 a significant correlation was observed between magnitude of coronary stenosis and left ventricular segmental dysfunction induced by ischemia in dogs submitted to positive stress tests. We conclude that the dobutamine and dipyridamole stress tests showed identical sensitivities for the detection of myocardial ischemia in this one-vessel disease animal model with a wide range of left circumflex artery

  1. MODEL PENSKORAN PARTIAL CREDIT PADA BUTIR MULTIPLE TRUE-FALSE BIDANG FISIKA

    Directory of Open Access Journals (Sweden)

    Wasis Wasis

    2013-01-01

    Full Text Available Tujuan penelitian ini menghasilkan model penskoran politomus untuk respons butir multiple true-false, sehingga dapat mengestimasi secara lebih akurat kemampuan di bidang fisika. Pengembangan penskoran menggunakan Four-D model dan diuji akurasinya melalui penelitian empiris dan simulasi. Penelitian empiris menggunakan 15 butir multiple true-false yang diambil dari soal UMPTN tahun 1996-2006 dan dikenakan pada 410 mahasiswa baru FMIPA Universitas Negeri Surabaya angkatan tahun 2007. Respons peserta tes diskor dengan tiga model partial credit (PCM I; II; dan III dan secara dikotomus. Hasil penskoran dianalisis dengan program Quest untuk mendapat-kan estimasi tingkat kesukaran butir (δ dan estimasi ke-mampuan peserta (θ untuk menentukan nilai fungsi informasi tes dan kesalahan baku estimasi. Penelitian simulasi mengguna-kan data bangkitan berdasarkan parameter empiris (δ dan θ memakai program statistik SAS dan akurasi estimasinya di-analisis dengan metode root mean squared error (RMSE. Hasil penelitian ini menunjukkan: (i Penskoran PCM dengan pem-bobotan mampu mengestimasi kemampuan lebih akurat di-bandingkan tanpa pembobotan maupun secara dikotomus; (ii Semakin banyak jumlah kategori dalam penskoran partial credit, semakin akurat. Kata kunci: model penskoran partial credit, butir multiple true-false ____________________________________________________________ THE PARTIAL CREDIT SCORING MODEL FOR THE MULTIPLE TRUE-FALSE BUTIRS IN PHYSICS Abstract This study is an attempt to overcome the weaknesses. This study aims to produce a polytomous scoring model for responses to multiple true-false butirs in order to get a more accurate estimation of abilities in physics. It adopts the Four-D model and its accuracy is assessed through empirical and simulation studies. The empirical study employed 15 multiple true-false butirs taken from the New Students Entrance Test of State University the year of 1996–2006. It administered to 410 new students enrolled

  2. Tribulus terrestris (Linn.) Attenuates Cellular Alterations Induced by Ischemia in H9c2 Cells Via Antioxidant Potential.

    Science.gov (United States)

    Reshma, P L; Lekshmi, V S; Sankar, Vandana; Raghu, K G

    2015-06-01

    Tribulus terrestris L. was evaluated for its cardioprotective property against myocardial ischemia in a cell line model. Initially, methanolic extract was prepared and subjected to sequential extraction with various solvents. The extract with high phenolic content (T. terrestris L. ethyl acetate extract-TTME) was further characterized for its chemical constituents and taken forward for evaluation against cardiac ischemia. HPLC analysis revealed the presence of phenolic compounds like caffeic acid (12.41 ± 0.22 mg g(-1)), chlorogenic acid (0.52 ± 0.06 mg g(-1)) and 4-hydroxybenzoic acid (0.60 ± 0.08 mg g(-1)). H9c2 cells were pretreated with TTME (10, 25, 50 and 100 µg/ml) for 24 h before the induction of ischemia. Then ischemia was induced by exposing cells to ischemia buffer, in a hypoxic chamber, maintained at 0.1% O2, 95% N2 and 5% CO2, for 1 h. A significant (p ≤ 0.05) increase in reactive oxygen species generation (56%), superoxide production (18%), loss of plasma membrane integrity, dissipation of transmembrane potential, permeability transition pore opening and apoptosis had been observed during ischemia. However, pretreatment with TTME was found to significantly (p ≤ 0.05) attenuate the alterations caused by ischemia. The overall results of this study partially reveal the scientific basis of the use of T. terrestris L. in the traditional system of medicine for heart diseases. Copyright © 2015 John Wiley & Sons, Ltd.

  3. An isotonic partial credit model for ordering subjects on the basis of their sum scores

    NARCIS (Netherlands)

    Ligtvoet, R.

    2012-01-01

    In practice, the sum of the item scores is often used as a basis for comparing subjects. For items that have more than two ordered score categories, only the partial credit model (PCM) and special cases of this model imply that the subjects are stochastically ordered on the common latent variable.

  4. A Comparison of Item Exposure Control Procedures with the Generalized Partial Credit Model

    Science.gov (United States)

    Sanchez, Edgar Isaac

    2008-01-01

    To enhance test security of high stakes tests, it is vital to understand the way various exposure control strategies function under various IRT models. To that end the present dissertation focused on the performance of several exposure control strategies under the generalized partial credit model with an item pool of 100 and 200 items. These…

  5. Methods for Assessing Item, Step, and Threshold Invariance in Polytomous Items Following the Partial Credit Model

    Science.gov (United States)

    Penfield, Randall D.; Myers, Nicholas D.; Wolfe, Edward W.

    2008-01-01

    Measurement invariance in the partial credit model (PCM) can be conceptualized in several different but compatible ways. In this article the authors distinguish between three forms of measurement invariance in the PCM: step invariance, item invariance, and threshold invariance. Approaches for modeling these three forms of invariance are proposed,…

  6. An Isotonic Partial Credit Model for Ordering Subjects on the Basis of Their Sum Scores

    Science.gov (United States)

    Ligtvoet, Rudy

    2012-01-01

    In practice, the sum of the item scores is often used as a basis for comparing subjects. For items that have more than two ordered score categories, only the partial credit model (PCM) and special cases of this model imply that the subjects are stochastically ordered on the common latent variable. However, the PCM is very restrictive with respect…

  7. Logical Specification and Analysis of Fault Tolerant Systems through Partial Model Checking

    NARCIS (Netherlands)

    Gnesi, S.; Etalle, Sandro; Mukhopadhyay, S.; Lenzini, Gabriele; Lenzini, G.; Martinelli, F.; Roychoudhury, A.

    2003-01-01

    This paper presents a framework for a logical characterisation of fault tolerance and its formal analysis based on partial model checking techniques. The framework requires a fault tolerant system to be modelled using a formal calculus, here the CCS process algebra. To this aim we propose a uniform

  8. TLR4 accessory molecule RP105 (CD180 regulates monocyte-driven arteriogenesis in a murine hind limb ischemia model.

    Directory of Open Access Journals (Sweden)

    Antonius J N M Bastiaansen

    Full Text Available AIMS: We investigated the role of the TLR4-accessory molecule RP105 (CD180 in post-ischemic neovascularization, i.e. arteriogenesis and angiogenesis. TLR4-mediated activation of pro-inflammatory Ly6Chi monocytes is crucial for effective neovascularization. Immunohistochemical analyses revealed that RP105+ monocytes are present in the perivascular space of remodeling collateral arterioles. As RP105 inhibits TLR4 signaling, we hypothesized that RP105 deficiency would lead to an unrestrained TLR4-mediated inflammatory response and hence to enhanced blood flow recovery after ischemia. METHODS AND RESULTS: RP105-/- and wild type (WT mice were subjected to hind limb ischemia and blood flow recovery was followed by Laser Doppler Perfusion Imaging. Surprisingly, we found that blood flow recovery was severely impaired in RP105-/- mice. Immunohistochemistry showed that arteriogenesis was reduced in these mice compared to the WT. However, both in vivo and ex vivo analyses showed that circulatory pro-arteriogenic Ly6Chi monocytes were more readily activated in RP105-/- mice. FACS analyses showed that Ly6Chi monocytes became activated and migrated to the affected muscle tissues in WT mice following induction of hind limb ischemia. Although Ly6Chi monocytes were readily activated in RP105-/- mice, migration into the ischemic tissues was hampered and instead, Ly6Chi monocytes accumulated in their storage compartments, bone marrow and spleen, in RP105-/- mice. CONCLUSIONS: RP105 deficiency results in an unrestrained inflammatory response and monocyte over-activation, most likely due to the lack of TLR4 regulation. Inappropriate, premature systemic activation of pro-inflammatory Ly6Chi monocytes results in reduced infiltration of Ly6Chi monocytes in ischemic tissues and in impaired blood flow recovery.

  9. Modeling biological gradient formation: combining partial differential equations and Petri nets.

    Science.gov (United States)

    Bertens, Laura M F; Kleijn, Jetty; Hille, Sander C; Heiner, Monika; Koutny, Maciej; Verbeek, Fons J

    2016-01-01

    Both Petri nets and differential equations are important modeling tools for biological processes. In this paper we demonstrate how these two modeling techniques can be combined to describe biological gradient formation. Parameters derived from partial differential equation describing the process of gradient formation are incorporated in an abstract Petri net model. The quantitative aspects of the resulting model are validated through a case study of gradient formation in the fruit fly.

  10. The study of the tolerance to skeletal muscle ischemia

    International Nuclear Information System (INIS)

    Tsubo, Masahiko; Takai, Hiroaki; Ikata, Takaaki; Sogabe, Takayuki; Miura, Iwao.

    1988-01-01

    A model of amputated and replanted legs were used for the study on the energy metabolism during long-period skeletal muscle ischemia. The energy metabolic changes and intracellular pH were measured continuously and non-invasively by 31 P-MRS technique. Immediately following ischemia, phosphocreatine declined and inorganic phosphate rose. However, ATP was maintained for 2 hours. During ischemia, phosphocreatine was not detected after about 3.5 hours and ATP was no longer detectable after about 5 hours. On the other hand, intracellular pH began declining linearly after 30 minutes. All cases of 4-hour ischemia and 57 % of 5-hour ischemia recovered. And all cases of 6-hour ischemia did not recover. (author)

  11. Reduced-order modelling of parameter-dependent, linear and nonlinear dynamic partial differential equation models.

    Science.gov (United States)

    Shah, A A; Xing, W W; Triantafyllidis, V

    2017-04-01

    In this paper, we develop reduced-order models for dynamic, parameter-dependent, linear and nonlinear partial differential equations using proper orthogonal decomposition (POD). The main challenges are to accurately and efficiently approximate the POD bases for new parameter values and, in the case of nonlinear problems, to efficiently handle the nonlinear terms. We use a Bayesian nonlinear regression approach to learn the snapshots of the solutions and the nonlinearities for new parameter values. Computational efficiency is ensured by using manifold learning to perform the emulation in a low-dimensional space. The accuracy of the method is demonstrated on a linear and a nonlinear example, with comparisons with a global basis approach.

  12. In vitro model of cerebral ischemia by using brain microvascular endothelial cells derived from human induced pluripotent stem cells.

    Science.gov (United States)

    Kokubu, Yasuhiro; Yamaguchi, Tomoko; Kawabata, Kenji

    2017-04-29

    Brain-derived microvascular endothelial cells (BMECs), which play a central role in blood brain barrier (BBB), can be used for the evaluation of drug transport into the brain. Although human BMEC cell lines have already been reported, they lack original properties such as barrier integrity. Pluripotent stem cells (PSCs) can be used for various applications such as regenerative therapy, drug screening, and pathological study. In the recent study, an induction method of BMECs from PSCs has been established, making it possible to more precisely study the in vitro human BBB function. Here, using induced pluripotent stem (iPS) cell-derived BMECs, we examined the effects of oxygen-glucose deprivation (OGD) and OGD/reoxygenation (OGD/R) on BBB permeability. OGD disrupted the barrier function, and the dysfunction was rapidly restored by re-supply of the oxygen and glucose. Interestingly, TNF-α, which is known to be secreted from astrocytes and microglia in the cerebral ischemia, prevented the restoration of OGD-induced barrier dysfunction in an apoptosis-independent manner. Thus, we could establish the in vitro BBB disease model that mimics the cerebral ischemia by using iPS cell-derived BMECs. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Pressure Combined with Ischemia/Reperfusion Injury Induces Deep Tissue Injury via Endoplasmic Reticulum Stress in a Rat Pressure Ulcer Model

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    Fei-Fei Cui

    2016-02-01

    Full Text Available Pressure ulcer is a complex and significant health problem in long-term bedridden patients, and there is currently no effective treatment or efficient prevention method. Furthermore, the molecular mechanisms and pathogenesis contributing to the deep injury of pressure ulcers are unclear. The aim of the study was to explore the role of endoplasmic reticulum (ER stress and Akt/GSK3β signaling in pressure ulcers. A model of pressure-induced deep tissue injury in adult Sprague-Dawley rats was established. Rats were treated with 2-h compression and subsequent 0.5-h release for various cycles. After recovery, the tissue in the compressed regions was collected for further analysis. The compressed muscle tissues showed clear cellular degenerative features. First, the expression levels of ER stress proteins GRP78, CHOP, and caspase-12 were generally increased compared to those in the control. Phosphorylated Akt and phosphorylated GSK3β were upregulated in the beginning of muscle compression, and immediately significantly decreased at the initiation of ischemia-reperfusion injury in compressed muscles tissue. These data show that ER stress may be involved in the underlying mechanisms of cell degeneration after pressure ulcers and that the Akt/GSK3β signal pathway may play an important role in deep tissue injury induced by pressure and ischemia/reperfusion.

  14. Factors associated with blood oxygen partial pressure and carbon dioxide partial pressure regulation during respiratory extracorporeal membrane oxygenation support: data from a swine model.

    Science.gov (United States)

    Park, Marcelo; Mendes, Pedro Vitale; Costa, Eduardo Leite Vieira; Barbosa, Edzangela Vasconcelos Santos; Hirota, Adriana Sayuri; Azevedo, Luciano Cesar Pontes

    2016-01-01

    The aim of this study was to explore the factors associated with blood oxygen partial pressure and carbon dioxide partial pressure. The factors associated with oxygen - and carbon dioxide regulation were investigated in an apneic pig model under veno-venous extracorporeal membrane oxygenation support. A predefined sequence of blood and sweep flows was tested. Oxygenation was mainly associated with extracorporeal membrane oxygenation blood flow (beta coefficient = 0.036mmHg/mL/min), cardiac output (beta coefficient = -11.970mmHg/L/min) and pulmonary shunting (beta coefficient = -0.232mmHg/%). Furthermore, the initial oxygen partial pressure and carbon dioxide partial pressure measurements were also associated with oxygenation, with beta coefficients of 0.160 and 0.442mmHg/mmHg, respectively. Carbon dioxide partial pressure was associated with cardiac output (beta coefficient = 3.578mmHg/L/min), sweep gas flow (beta coefficient = -2.635mmHg/L/min), temperature (beta coefficient = 4.514mmHg/ºC), initial pH (beta coefficient = -66.065mmHg/0.01 unit) and hemoglobin (beta coefficient = 6.635mmHg/g/dL). In conclusion, elevations in blood and sweep gas flows in an apneic veno-venous extracorporeal membrane oxygenation model resulted in an increase in oxygen partial pressure and a reduction in carbon dioxide partial pressure 2, respectively. Furthermore, without the possibility of causal inference, oxygen partial pressure was negatively associated with pulmonary shunting and cardiac output, and carbon dioxide partial pressure was positively associated with cardiac output, core temperature and initial hemoglobin.

  15. Partial widths of boson resonances in the quark-gluon model of strong interactions

    International Nuclear Information System (INIS)

    Kaidalov, A.B.; Volkovitsky, P.E.

    1981-01-01

    The quark-gluon model of strong interactions based on the topological expansion and the string model ib used for the calculation of the partial widths of boson resonances in the channels with two pseudoscalar mesons. The partial widths of mesons with arbitrary spins lying on the vector and tensor Regge trajectories are expressed in terms of the only rho-meson width. The violation of SU(3) symmetry increases with the growth of the spin of the resonance. The theoretical predictions are in a good agreement with experimental data [ru

  16. Anti-Inflammatory Effects of Traditional Chinese Medicines against Ischemic Injury in In Vivo Models of Cerebral Ischemia

    Directory of Open Access Journals (Sweden)

    Chin-Yi Cheng

    2016-01-01

    Full Text Available Inflammation plays a crucial role in the pathophysiology of acute ischemic stroke. In the ischemic cascade, resident microglia are rapidly activated in the brain parenchyma and subsequently trigger inflammatory mediator release, which facilitates leukocyte-endothelial cell interactions in inflammation. Activated leukocytes invade the endothelial cell junctions and destroy the blood-brain barrier integrity, leading to brain edema. Toll-like receptors (TLRs stimulation in microglia/macrophages through the activation of intercellular signaling pathways secretes various proinflammatory cytokines and enzymes and then aggravates cerebral ischemic injury. The secreted cytokines activate the proinflammatory transcription factors, which subsequently regulate cytokine expression, leading to the amplification of the inflammatory response and exacerbation of the secondary brain injury. Traditional Chinese medicines (TCMs, including TCM-derived active compounds, Chinese herbs, and TCM formulations, exert neuroprotective effects against inflammatory responses by downregulating the following: ischemia-induced microglial activation, microglia/macrophage-mediated cytokine production, proinflammatory enzyme production, intercellular adhesion molecule-1, matrix metalloproteinases, TLR expression, and deleterious transcription factor activation. TCMs also aid in upregulating anti-inflammatory cytokine expression and neuroprotective transcription factor activation in the ischemic lesion in the inflammatory cascade during the acute phase of cerebral ischemia. Thus, TCMs exert potent anti-inflammatory properties in ischemic stroke and warrant further investigation.

  17. Assessment of protective effects of pheniramine maleate on reperfusion injury in lung after distant organ ischemia: a rat model.

    Science.gov (United States)

    Gokalp, Orhan; Yurekli, Ismail; Kiray, Muge; Bagriyanik, Alper; Yetkin, Ufuk; Yurekli, Banu Sarer; Gur, Serkan; Aksun, Murat; Satoglu, Ismail Safa; Gokalp, Gamze; Gurbuz, Ali

    2013-04-01

    The aim of this study is to investigate the protective effects of methylprednisolone (MP) and pheniramine maleate (PM) on reperfusion injury of lungs developing after ischemia of the left lower extremity of rats. A total of 28 randomly selected male rats were divided into 4 groups, each consisting of 7 rats. Group 1 was the control group. Group 2 was the sham group (ischemia/reperfusion [I/R]). Rats in group 3 were subjected to I/R and given PM (Ph group) and rats in group 4 were subjected to I/R and given MP (Pn group). Malondialdehyde levels were significantly lower in Ph group than in I/R group (P < .05). Superoxide dismutase and glutathione peroxidase enzyme activities were found to be significantly higher in Ph group than in the I/R group (P < .05). Histological examination demonstrated that PM had protective effects against I/R injury. The PM has a protective effect against I/R injury in rat lung.

  18. [Brain protection against cerebral ischemia].

    Science.gov (United States)

    Kitagawa, Kazuo

    2013-01-01

    Previous clinical trials failed to show the benefit of several potentially protective drugs in acute ischemic stroke. However, there would be three main approaches for brain protection against stroke. The first is to develop a novel thrombolytic agent which is more efficient and safer than alteplase. Tenecteplase and desmoteplase are in progress as a new thrombolytic drug. The second strategy is to augment collateral circulation through leptomeningeal anastomosis. Administration of G-CSF could enhance arteriogenesis, but it takes several days to develop functional collateral. For this purpose, partial aortic balloon clumping or stimulation of pterygopalatine ganglion may be promising. The third one is to protect neurovascular unit against reperfusion injury. Brain hypothermia is the most effective strategy in experimental ischemia, and the clinical trial for hypothermia combined with thrombolysis therapy is in progress. Activation of endogenous protective response, as presented by ischemic tolerance, has focused on remote ischemic conditioning. Although the precise mechanisms of remote preconditioning remain unclear, intermittent limb ischemia is a safe approach. Remote ischemic conditioning is now investigated in acute patients with thrombolysis therapy.

  19. The protective effect of cilostazol on isolated rabbit femoral arteries under conditions of ischemia and reperfusion: the role of the nitric oxide pathway

    Directory of Open Access Journals (Sweden)

    Mariana R.G.A. Santos

    2012-01-01

    Full Text Available OBJECTIVES: The clinical significance of ischemia/reperfusion of the lower extremities demands further investigation to enable the development of more effective therapeutic alternatives. This study investigated the changes in the vascular reactivity of the rabbit femoral artery and nitric oxide metabolites under partial ischemia/ reperfusion conditions following cilostazol administration. METHODS: Ischemia was induced using infrarenal aortic clamping. The animals were randomly divided into seven groups: Control 90 minutes, Ischemia/Reperfusion 90/60 minutes, Control 120 minutes, Ischemia/Reperfusion 120/90 minutes, Cilostazol, Cilostazol before Ischemia/Reperfusion 120/90 minutes, and Ischemia 120 minutes/Cilostazol/ Reperfusion 90 minutes. Dose-response curves for sodium nitroprusside, acetylcholine, and the calcium ionophore A23187 were obtained in isolated femoral arteries. The levels of nitrites and nitrates in the plasma and skeletal muscle were determined using chemiluminescence. RESULTS: Acetylcholine-and A23187-induced relaxation was reduced in the Ischemia/Reperfusion 120/90 group, and treatment with cilostazol partially prevented this ischemia/reperfusion-induced endothelium impairment. Only cilostazol treatment increased plasma levels of nitrites and nitrates. An elevation in the levels of nitrites and nitrates was observed in muscle tissues in the Ischemia/Reperfusion 120/90, Cilostazol/Ischemia/Reperfusion, and Ischemia/ Cilostazol/Reperfusion groups. CONCLUSION: Hind limb ischemia/reperfusion yielded an impaired endothelium-dependent relaxation of the femoral artery. Furthermore, cilostazol administration prior to ischemia exerted a protective effect on endotheliumdependent vascular reactivity under ischemia/reperfusion conditions.

  20. Highly accelerated cardiac cine parallel MRI using low-rank matrix completion and partial separability model

    Science.gov (United States)

    Lyu, Jingyuan; Nakarmi, Ukash; Zhang, Chaoyi; Ying, Leslie

    2016-05-01

    This paper presents a new approach to highly accelerated dynamic parallel MRI using low rank matrix completion, partial separability (PS) model. In data acquisition, k-space data is moderately randomly undersampled at the center kspace navigator locations, but highly undersampled at the outer k-space for each temporal frame. In reconstruction, the navigator data is reconstructed from undersampled data using structured low-rank matrix completion. After all the unacquired navigator data is estimated, the partial separable model is used to obtain partial k-t data. Then the parallel imaging method is used to acquire the entire dynamic image series from highly undersampled data. The proposed method has shown to achieve high quality reconstructions with reduction factors up to 31, and temporal resolution of 29ms, when the conventional PS method fails.

  1. Simplified Method for Modeling the Impact of Arbitrary Partial Shading Conditions on PV Array Performance: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    MacAlpine, Sara; Deline, Chris

    2015-09-15

    It is often difficult to model the effects of partial shading conditions on PV array performance, as shade losses are nonlinear and depend heavily on a system's particular configuration. This work describes and implements a simple method for modeling shade loss: a database of shade impact results (loss percentages), generated using a validated, detailed simulation tool and encompassing a wide variety of shading scenarios. The database is intended to predict shading losses in crystalline silicon PV arrays and is accessed using basic inputs generally available in any PV simulation tool. Performance predictions using the database are within 1-2% of measured data for several partially shaded PV systems, and within 1% of those predicted by the full, detailed simulation tool on an annual basis. The shade loss database shows potential to considerably improve performance prediction for partially shaded PV systems.

  2. Effect of nano-silver hydrogel coating film on deep partial thickness scald model of rabbit

    OpenAIRE

    Peng Xi; Yan Li; Xiaojin Ge; Dandan Liu; Mingsan Miao

    2018-01-01

    Objective: Observing the effect of nano-silver hydrogel coating film on deep partial thickness scald model of rabbit. Method: We prepared boiling water scalded rabbits with deep II degree scald models and applied high, medium and low doses of nano-silver hydrogel coating film for different time and area. Then we compared the difference of burned paper weight before administration and after administration model burns, burn local skin irritation points infection, skin crusting and scabs from th...

  3. Skew-t partially linear mixed-effects models for AIDS clinical studies.

    Science.gov (United States)

    Lu, Tao

    2016-01-01

    We propose partially linear mixed-effects models with asymmetry and missingness to investigate the relationship between two biomarkers in clinical studies. The proposed models take into account irregular time effects commonly observed in clinical studies under a semiparametric model framework. In addition, commonly assumed symmetric distributions for model errors are substituted by asymmetric distribution to account for skewness. Further, informative missing data mechanism is accounted for. A Bayesian approach is developed to perform parameter estimation simultaneously. The proposed model and method are applied to an AIDS dataset and comparisons with alternative models are performed.

  4. Implementing The Automated Phases Of The Partially-Automated Digital Triage Process Model

    Directory of Open Access Journals (Sweden)

    Gary D Cantrell

    2012-12-01

    Full Text Available Digital triage is a pre-digital-forensic phase that sometimes takes place as a way of gathering quick intelligence. Although effort has been undertaken to model the digital forensics process, little has been done to date to model digital triage. This work discuses the further development of a model that does attempt to address digital triage the Partially-automated Crime Specific Digital Triage Process model. The model itself will be presented along with a description of how its automated functionality was implemented to facilitate model testing.

  5. Retrograde Renal Cooling to Minimize Ischemia

    Directory of Open Access Journals (Sweden)

    Janet L. Colli

    2013-01-01

    Full Text Available Objective: During partial nephrectomy, renal hypothermia has been shown to decrease ischemia induced renal damage which occurs from renal hilar clamping. In this study we investigate the infusion rate required to safely cool the entire renal unit in a porcine model using retrograde irrigation of iced saline via dual-lumen ureteral catheter. Materials and Methods: Renal cortical, renal medullary, bowel and rectal temperatures during retrograde cooling in a laparoscopic porcine model were monitored in six renal units. Iced normal saline was infused at 300 cc/hour, 600 cc/hour, 1000 cc/hour and gravity (800 cc/hour for 600 seconds with and without hilar clamping. Results: Retrograde cooling with hilar clamping provided rapid medullary renal cooling and significant hypothermia of the medulla and cortex at infusion rates ≥ 600 cc/hour. With hilar clamping, cortical temperatures decreased at -0.9° C/min. reaching a threshold temperature of 26.9° C, and medullary temperatures decreased at -0.90 C/min. reaching a temperature of 26.1° C over 600 seconds on average for combined data at infusion rates ≥ 600 cc/hour. The lowest renal temperatures were achieved with gravity infusion. Without renal hilum clamping, retrograde cooling was minimal at all infusion rates. Conclusions: Significant renal cooling by gravity infusion of iced cold saline via a duel lumen catheter with a clamped renal hilum was achieved in a porcine model. Continuous retrograde irrigation with iced saline via a two way ureteral catheter may be an effective method to induce renal hypothermia in patients undergoing robotic assisted and/or laparoscopic partial nephrectomy.

  6. Efeito renoprotetor da estatina: modelo animal de isquemia-reperfusão Renoprotective effect of statin: a ischemia-reperfusion animal model

    Directory of Open Access Journals (Sweden)

    Claudia Akemi Shibuya Teshima

    2010-09-01

    , with antioxidant, antiinflamatory and vascular actions. The heme oxygenase-1 (HO-1 can be involved in these pleitropic effects of statin on the renal function. This study was performed in order to evaluate if the renoprotective effect of the statin is a heme mechanism of protection in rats. METHODS: The ischemic model was reproduced by through clamping the bilateral renal pedicles for 30 minutes followed by reperfusion. Adult Wistar rats, weighting from 250-300g, were divided into the following groups: SHAM (control; Ischemia (30 minutes renal ischemia; Ischemia+Statin (sinvastatin 0.5mg/kg,orally (v.o. for 3 days; Ischemia+Hemin (Hemin, 1.0mg/100g, intraperitoneal (i.p., 24 hours before surgery; Ischemia+SnPP (SnPP 2μmol/kg, i.p., 24 hours before surgery ; Ischemia+Statin+Hemin; Ischemia+Statin+SnPP. RF (clearance of creatinine, Jaffé method, urinary peroxides (UP, urinary osmolality (UO and immunohistochemical for ED-1 were evaluated. RESULTS: Results showed that sinvastatin ameliorated RF, urinary osmolality, reduced the UP excrection and the macrophage infiltration in rats submitted to renal ischemia. The inducer of HO-1 and its association with sinvastatin induced a similar pattern of improvement of renal function. CONCLUSION: the study confirmed the renoprotective effect of the statins on renal function, with antioxidant and antiinflamatory actions, and it suggests that this effect can have an interface with the heme system of renal protection.

  7. Characterization of Microparticles after Hepatic Ischemia-Reperfusion Injury

    Science.gov (United States)

    Freeman, Christopher M.; Quillin, Ralph C.; Wilson, Gregory C.; Nojima, Hiroyuki; Johnson, Bobby L.; Sutton, Jeffrey M.; Schuster, Rebecca M.; Blanchard, John; Edwards, Michael J.; Caldwell, Charles C.; Lentsch, Alex B.

    2014-01-01

    Background Hepatic ischemia-reperfusion (I/R) is a well-studied model of liver injury and has demonstrated a biphasic injury followed by recovery and regeneration. Microparticles (MPs) are a developing field of study and these small membrane bound vesicles have been shown to have effector function in other physiologic and pathologic states. This study was designed to quantify the levels of MPs from various cell origins–platelets, neutrophils, and endolethial cells–following hepatic ischemia-reperfusion injury. Methods A murine model was used with mice undergoing 90 minutes of partial hepatic ischemia followed by various times of reperfusion. Following reperfusion, plasma samples were taken and MPs of various cell origins were labeled and levels were measured using flow cytometry. Additionally, cell specific MPs were further assessed by Annexin V, which stains for the presence of phosphatidylserine, a cell surface marker linked to apoptosis. Statistical analysis was performed using one-way analysis of variance with subsequent Student-Newman-Keuls test with data presented as the mean and standard error of the mean. Results MPs from varying sources show an increase in circulating levels following hepatic I/R injury. However, the timing of the appearance of different MP subtypes differs for each cell type. Platelet and neutrophil-derived MP levels demonstrated an acute elevation following injury whereas endothelial-derived MP levels demonstrated a delayed elevation. Conclusion This is the first study to characterize circulating levels of cell-specific MPs after hepatic I/R injury and suggests that MPs derived from platelets and neutrophils serve as markers of inflammatory injury and may be active participants in this process. In contrast, MPs derived from endothelial cells increase after the injury response during the reparative phase and may be important in angiogenesis that occurs in the regenerating liver. PMID:24879335

  8. Inference in partially identified models with many moment inequalities using Lasso

    DEFF Research Database (Denmark)

    Bugni, Federico A.; Caner, Mehmet; Kock, Anders Bredahl

    This paper considers the problem of inference in a partially identified moment (in)equality model with possibly many moment inequalities. Our contribution is to propose a novel two-step new inference method based on the combination of two ideas. On the one hand, our test statistic and critical...

  9. Application of partial differential equation modeling of the control/structural dynamics of flexible spacecraft

    Science.gov (United States)

    Taylor, Lawrence W., Jr.; Rajiyah, H.

    1991-01-01

    Partial differential equations for modeling the structural dynamics and control systems of flexible spacecraft are applied here in order to facilitate systems analysis and optimization of these spacecraft. Example applications are given, including the structural dynamics of SCOLE, the Solar Array Flight Experiment, the Mini-MAST truss, and the LACE satellite. The development of related software is briefly addressed.

  10. Parent Ratings of ADHD Symptoms: Generalized Partial Credit Model Analysis of Differential Item Functioning across Gender

    Science.gov (United States)

    Gomez, Rapson

    2012-01-01

    Objective: Generalized partial credit model, which is based on item response theory (IRT), was used to test differential item functioning (DIF) for the "Diagnostic and Statistical Manual of Mental Disorders" (4th ed.), inattention (IA), and hyperactivity/impulsivity (HI) symptoms across boys and girls. Method: To accomplish this, parents completed…

  11. New model reduction technique for a class of parabolic partial differential equations

    NARCIS (Netherlands)

    Vajta, Miklos

    1991-01-01

    A model reduction (or lumping) technique for a class of parabolic-type partial differential equations is given, and its application is discussed. The frequency response of the temperature distribution in any multilayer solid is developed and given by a matrix expression. The distributed transfer

  12. Applying a Weighted Maximum Likelihood Latent Trait Estimator to the Generalized Partial Credit Model

    Science.gov (United States)

    Penfield, Randall D.; Bergeron, Jennifer M.

    2005-01-01

    This article applies a weighted maximum likelihood (WML) latent trait estimator to the generalized partial credit model (GPCM). The relevant equations required to obtain the WML estimator using the Newton-Raphson algorithm are presented, and a simulation study is described that compared the properties of the WML estimator to those of the maximum…

  13. On the Existence and Uniqueness of JML Estimates for the Partial Credit Model

    Science.gov (United States)

    Bertoli-Barsotti, Lucio

    2005-01-01

    A necessary and sufficient condition is given in this paper for the existence and uniqueness of the maximum likelihood (the so-called joint maximum likelihood) estimate of the parameters of the Partial Credit Model. This condition is stated in terms of a structural property of the pattern of the data matrix that can be easily verified on the basis…

  14. Strategies for Controlling Item Exposure in Computerized Adaptive Testing with the Generalized Partial Credit Model

    Science.gov (United States)

    Davis, Laurie Laughlin

    2004-01-01

    Choosing a strategy for controlling item exposure has become an integral part of test development for computerized adaptive testing (CAT). This study investigated the performance of six procedures for controlling item exposure in a series of simulated CATs under the generalized partial credit model. In addition to a no-exposure control baseline…

  15. Exploring Alternative Characteristic Curve Approaches to Linking Parameter Estimates from the Generalized Partial Credit Model.

    Science.gov (United States)

    Roberts, James S.; Bao, Han; Huang, Chun-Wei; Gagne, Phill

    Characteristic curve approaches for linking parameters from the generalized partial credit model were examined for cases in which common (anchor) items are calibrated separately in two groups. Three of these approaches are simple extensions of the test characteristic curve (TCC), item characteristic curve (ICC), and operating characteristic curve…

  16. Sulfur Speciation of Crude Oils by Partial Least Squares Regression Modeling of Their Infrared Spectra

    NARCIS (Netherlands)

    de Peinder, P.; Visser, T.; Wagemans, R.W.P.; Blomberg, J.; Chaabani, H.; Soulimani, F.; Weckhuysen, B.M.

    2013-01-01

    Research has been carried out to determine the feasibility of partial least-squares regression (PLS) modeling of infrared (IR) spectra of crude oils as a tool for fast sulfur speciation. The study is a continuation of a previously developed method to predict long and short residue properties of

  17. Rat experimental model of myocardial ischemia/reperfusion injury: an ethical approach to set up the analgesic management of acute post-surgical pain.

    Directory of Open Access Journals (Sweden)

    Maria Chiara Ciuffreda

    Full Text Available RATIONALE: During the past 30 years, myocardial ischemia/reperfusion injury in rodents became one of the most commonly used model in cardiovascular research. Appropriate pain-prevention appears critical since it may influence the outcome and the results obtained with this model. However, there are no proper guidelines for pain management in rats undergoing thoracic surgery. Accordingly, we evaluated three analgesic regimens in cardiac ischemia/reperfusion injury. This study was strongly focused on 3R's ethic principles, in particular the principle of Reduction. METHODS: Rats undergoing surgery were treated with pre-surgical tramadol (45 mg/kg intra-peritoneal, or carprofen (5 mg/kg sub-cutaneous, or with pre-surgical administration of carprofen followed by 2 post-surgery tramadol injections (multi-modal group. We assessed behavioral signs of pain and made a subjective evaluation of stress and suffering one and two hours after surgery. RESULTS: Multi-modal treatment significantly reduced the number of signs of pain compared to carprofen alone at both the first hour (61±42 vs 123±47; p<0.05 and the second hour (43±21 vs 74±24; p<0.05 post-surgery. Tramadol alone appeared as effective as multi-modal treatment during the first hour, but signs of pain significantly increased one hour later (from 66±72 to 151±86, p<0.05. Carprofen alone was more effective at the second hour post-surgery when signs of pain reduced to 74±24 from 113±40 in the first hour (p<0.05. Stress behaviors during the second hour were observed in only 20% of rats in the multimodal group compared to 75% and 86% in the carprofen and tramadol groups, respectively (p<0.05. CONCLUSIONS: Multi-modal treatment with carprofen and tramadol was more effective in preventing pain during the second hour after surgery compared with both tramadol or carprofen. Our results suggest that the combination of carprofen and tramadol represent the best therapy to prevent animal pain after

  18. Arterially perfused neurosphere-derived cells distribute outside the ischemic core in a model of transient focal ischemia and reperfusion in vitro.

    Directory of Open Access Journals (Sweden)

    Chiara Pastori

    Full Text Available BACKGROUND: Treatment with neural stem cells represents a potential strategy to improve functional recovery of post-ischemic cerebral injury. The potential benefit of such treatment in acute phases of human ischemic stroke depends on the therapeutic viability of a systemic vascular delivery route. In spite of the large number of reports on the beneficial effects of intracerebral stem cells injection in experimental stroke, very few studies demonstrated the effectiveness of the systemic intravenous delivery approach. METODOLOGY/PRINCIPAL FINDINGS: We utilized a novel in vitro model of transient focal ischemia to analyze the brain distribution of neurosphere-derived cells (NCs in the early 3 hours that follow transient occlusion of the medial cerebral artery (MCA. NCs obtained from newborn C57/BL6 mice are immature cells with self-renewal properties that could differentiate into neurons, astrocytes and oligodendrocytes. MCA occlusion for 30 minutes in the in vitro isolated guinea pig brain preparation was followed by arterial perfusion with 1x10(6 NCs charged with a green fluorescent dye, either immediately or 60 minutes after reperfusion onset. Changes in extracellular pH and K(+ concentration during and after MCAO were measured through ion-sensitive electrodes. CONCLUSION/SIGNIFICANCE: It is demonstrated that NCs injected through the vascular system do not accumulate in the ischemic core and preferentially distribute in non-ischemic areas, identified by combined electrophysiological and morphological techniques. Direct measurements of extracellular brain ions during and after MCA occlusion suggest that anoxia-induced tissue changes, such as extracellular acidosis, may prevent NCs from entering the ischemic area in our in vitro model of transitory focal ischemia and reperfusion suggesting a role played by the surrounding microenviroment in driving NCs outside the ischemic core. These findings strongly suggest that the potential beneficial effect

  19. Rosiglitazone Affects Nitric Oxide Synthases and Improves Renal Outcome in a Rat Model of Severe Ischemia/Reperfusion Injury

    Directory of Open Access Journals (Sweden)

    Boris Betz

    2012-01-01

    Full Text Available Background. Nitric oxide (NO-signal transduction plays an important role in renal ischemia/reperfusion (I/R injury. NO produced by endothelial NO-synthase (eNOS has protective functions whereas NO from inducible NO-synthase (iNOS induces impairment. Rosiglitazone (RGZ, a peroxisome proliferator-activated receptor (PPAR-γ agonist exerted beneficial effects after renal I/R injury, so we investigated whether this might be causally linked with NOS imbalance. Methods. RGZ (5 mg/kg was administered i.p. to SD-rats (f subjected to bilateral renal ischemia (60 min. Following 24 h of reperfusion, inulin- and PAH-clearance as well as PAH-net secretion were determined. Morphological alterations were graded by histopathological scoring. Plasma NOx-production was measured. eNOS and iNOS expression was analyzed by qPCR. Cleaved caspase 3 (CC3 was determined as an apoptosis indicator and ED1 as a marker of macrophage infiltration in renal tissue. Results. RGZ improves renal function after renal I/R injury (PAH-/inulin-clearance, PAH-net secretion and reduces histomorphological injury. Additionally, RGZ reduces NOx plasma levels, ED-1 positive cell infiltration and CC3 expression. iNOS-mRNA is reduced whereas eNOS-mRNA is increased by RGZ. Conclusion. RGZ has protective properties after severe renal I/R injury. Alterations of the NO pathway regarding eNOS and iNOS could be an explanation of the underlying mechanism of RGZ protection in renal I/R injury.

  20. Ischemia-reperfusion rat model of acute pancreatitis: protein carbonyl as a putative early biomarker of pancreatic injury.

    Science.gov (United States)

    Schanaider, Alberto; de Carvalho, Thales Penna; de Oliveira Coelho, Simone; Renteria, Juan Miguel; Eleuthério, Elis Cristina Araújo; Castelo-Branco, Morgana Teixeira Lima; Madi, Kalil; Baetas-da-Cruz, Wagner; de Souza, Heitor Siffert Pereira

    2015-08-01

    Acute pancreatitis (AP) is an inflammatory disorder that can affect adjacent and/or remote organs. Some evidence indicates that the production of reactive oxygen species is able to induce AP. Protein carbonyl (PC) derivatives, which can also be generated through oxidative cleavage mechanisms, have been implicated in several diseases, but there is little or no information on this biomarker in AP. We investigated the association between some inflammatory mediators and PC, with the severity of ischemia-reperfusion AP. Wistar rats (n = 56) were randomly assigned in the following groups : control; sham, 15- or 180-min clamping of splenic artery, with 24 or 72 h of follow-up. The relationships between serum level of PC and thiobarbituric acid reactive species (TBARS) to myeloperoxidase (MPO) activity in tissue homogenates and to cytokines in culture supernatants of pancreatic samples were analyzed. MPO activity was related to the histology scores and increased in all clamping groups. Tumor necrosis factor-alpha (TNF-α), interleukin 1 beta (IL-1β), and interleukin-6 were higher in the 180-min groups. Significant correlations were found between MPO activity and the concentrations of TNF-α and IL-1β. PC levels increased in the 15-min to 24-h group. TBARS levels were not altered substantially. MPO activity and TNF-α and IL-1β concentrations in pancreatic tissue are correlated with AP severity. Serum levels of PC appear to begin to rise early in the course of the ischemia-reperfusion AP and are no longer detected at later stages in the absence of severe pancreatitis. These data suggest that PC can be an efficient tool for the diagnosis of early stages of AP.

  1. Average intensity and spreading of partially coherent model beams propagating in a turbulent biological tissue

    International Nuclear Information System (INIS)

    Wu, Yuqian; Zhang, Yixin; Wang, Qiu; Hu, Zhengda

    2016-01-01

    For Gaussian beams with three different partially coherent models, including Gaussian-Schell model (GSM), Laguerre-Gaussian Schell-model (LGSM) and Bessel-Gaussian Schell-model (BGSM) beams propagating through a biological turbulent tissue, the expression of the spatial coherence radius of a spherical wave propagating in a turbulent biological tissue, and the average intensity and beam spreading for GSM, LGSM and BGSM beams are derived based on the fractal model of power spectrum of refractive-index variations in biological tissue. Effects of partially coherent model and parameters of biological turbulence on such beams are studied in numerical simulations. Our results reveal that the spreading of GSM beams is smaller than LGSM and BGSM beams on the same conditions, and the beam with larger source coherence width has smaller beam spreading than that with smaller coherence width. The results are useful for any applications involved light beam propagation through tissues, especially the cases where the average intensity and spreading properties of the light should be taken into account to evaluate the system performance and investigations in the structures of biological tissue. - Highlights: • Spatial coherence radius of a spherical wave propagating in a turbulent biological tissue is developed. • Expressions of average intensity and beam spreading for GSM, LGSM and BGSM beams in a turbulent biological tissue are derived. • The contrast for the three partially coherent model beams is shown in numerical simulations. • The results are useful for any applications involved light beam propagation through tissues.

  2. Constraints on the rheology of the partially molten mantle from numerical models of laboratory experiments

    Science.gov (United States)

    Rudge, J. F.; Alisic Jewell, L.; Rhebergen, S.; Katz, R. F.; Wells, G. N.

    2015-12-01

    One of the fundamental components in any dynamical model of melt transport is the rheology of partially molten rock. This rheology is poorly understood, and one way in which a better understanding can be obtained is by comparing the results of laboratory deformation experiments to numerical models. Here we present a comparison between numerical models and the laboratory setup of Qi et al. 2013 (EPSL), where a cylinder of partially molten rock containing rigid spherical inclusions was placed under torsion. We have replicated this setup in a finite element model which solves the partial differential equations describing the mechanical process of compaction. These computationally-demanding 3D simulations are only possible due to the recent development of a new preconditioning method for the equations of magma dynamics. The experiments show a distinct pattern of melt-rich and melt-depleted regions around the inclusions. In our numerical models, the pattern of melt varies with key rheological parameters, such as the ratio of bulk to shear viscosity, and the porosity- and strain-rate-dependence of the shear viscosity. These observed melt patterns therefore have the potential to constrain rheological properties. While there are many similarities between the experiments and the numerical models, there are also important differences, which highlight the need for better models of the physics of two-phase mantle/magma dynamics. In particular, the laboratory experiments display more pervasive melt-rich bands than is seen in our numerics.

  3. Doubly robust estimation of generalized partial linear models for longitudinal data with dropouts.

    Science.gov (United States)

    Lin, Huiming; Fu, Bo; Qin, Guoyou; Zhu, Zhongyi

    2017-12-01

    We develop a doubly robust estimation of generalized partial linear models for longitudinal data with dropouts. Our method extends the highly efficient aggregate unbiased estimating function approach proposed in Qu et al. (2010) to a doubly robust one in the sense that under missing at random (MAR), our estimator is consistent when either the linear conditional mean condition is satisfied or a model for the dropout process is correctly specified. We begin with a generalized linear model for the marginal mean, and then move forward to a generalized partial linear model, allowing for nonparametric covariate effect by using the regression spline smoothing approximation. We establish the asymptotic theory for the proposed method and use simulation studies to compare its finite sample performance with that of Qu's method, the complete-case generalized estimating equation (GEE) and the inverse-probability weighted GEE. The proposed method is finally illustrated using data from a longitudinal cohort study. © 2017, The International Biometric Society.

  4. A regional and nonstationary model for partial duration series of extreme rainfall

    DEFF Research Database (Denmark)

    Gregersen, Ida Bülow; Madsen, Henrik; Rosbjerg, Dan

    2017-01-01

    as the explanatory variables in the regional and temporal domain, respectively. Further analysis of partial duration series with nonstationary and regional thresholds shows that the mean exceedances also exhibit a significant variation in space and time for some rainfall durations, while the shape parameter is found...... of extreme rainfall. The framework is built on a partial duration series approach with a nonstationary, regional threshold value. The model is based on generalized linear regression solved by generalized estimation equations. It allows a spatial correlation between the stations in the network and accounts...... furthermore for variable observation periods at each station and in each year. Marginal regional and temporal regression models solved by generalized least squares are used to validate and discuss the results of the full spatiotemporal model. The model is applied on data from a large Danish rain gauge network...

  5. Metabolic Adaptation to Muscle Ischemia

    Science.gov (United States)

    Cabrera, Marco E.; Coon, Jennifer E.; Kalhan, Satish C.; Radhakrishnan, Krishnan; Saidel, Gerald M.; Stanley, William C.

    2000-01-01

    Although all tissues in the body can adapt to varying physiological/pathological conditions, muscle is the most adaptable. To understand the significance of cellular events and their role in controlling metabolic adaptations in complex physiological systems, it is necessary to link cellular and system levels by means of mechanistic computational models. The main objective of this work is to improve understanding of the regulation of energy metabolism during skeletal/cardiac muscle ischemia by combining in vivo experiments and quantitative models of metabolism. Our main focus is to investigate factors affecting lactate metabolism (e.g., NADH/NAD) and the inter-regulation between carbohydrate and fatty acid metabolism during a reduction in regional blood flow. A mechanistic mathematical model of energy metabolism has been developed to link cellular metabolic processes and their control mechanisms to tissue (skeletal muscle) and organ (heart) physiological responses. We applied this model to simulate the relationship between tissue oxygenation, redox state, and lactate metabolism in skeletal muscle. The model was validated using human data from published occlusion studies. Currently, we are investigating the difference in the responses to sudden vs. gradual onset ischemia in swine by combining in vivo experimental studies with computational models of myocardial energy metabolism during normal and ischemic conditions.

  6. Release of Tissue-specific Proteins into Coronary Perfusate as a Model for Biomarker Discovery in Myocardial Ischemia/Reperfusion Injury

    DEFF Research Database (Denmark)

    Cordwell, Stuart; Edwards, Alistair; Liddy, Kiersten

    2012-01-01

    -rich plasma, in which the wide dynamic range of the native protein complement hinders classical proteomic investigations. We employed an ex vivo rabbit model of myocardial ischemia/reperfusion (I/R) injury using Langendorff buffer perfusion. Nonrecirculating perfusate was collected over a temporal profile...... reperfusion post-15I. Proteins released during irreversible I/R (60I/60R) were profiled using gel-based (2-DE and one-dimensional gel electrophoresis coupled to liquid chromatography and tandem mass spectrometry; geLC–MS) and gel-free (LC–MS/MS) methods. A total of 192 tissue-specific proteins were identified...... release using ex vivo buffer perfused tissue to limit the presence of obfuscating plasma proteins may identify candidates for further study in humans....

  7. Partial splenectomy and autotransplantation of splenic fragments in pigs: a model for prevention of septicemia

    International Nuclear Information System (INIS)

    Pabst, R.; Binns, R.M.

    1986-01-01

    Normal young piglets and miniature piglets of the Gottingen breed were used as animal models for autotransplantation of splenic fragments. In pigs, regeneration kinetics seem to be comparable to man. Even after six mo, only small splenic nodules with a reduced blood flow were found. No effective stimulator of splenic regeneration has been found for pigs. Pig spleen size and blood supply enable partial splenectomies and ligation of the splenic artery which are models for spleen surgery in man

  8. Heart Protection by Combination Therapy with Esmolol and Milrinone at Late-Ischemia and Early Reperfusion

    OpenAIRE

    Huang, Ming-He; Wu, Yewen; Nguyen, Vincent; Rastogi, Saurabh; McConnell, Bradley K.; Wijaya, Cori; Uretsky, Barry F.; Poh, Kian-Keong; Tan, Huay-Cheem; Fujise, Kenichi

    2011-01-01

    Introduction The present study determined whether late-ischemia/early reperfusion therapy with the β1-adrenergic receptor (AR) blocker esmolol and phosphodiesterase III inhibitor milrinone reduced left ventricular (LV) myocardial infarct size (IS). Methods and Results In an ischemia/reperfusion rat model (30-min ischemia/4-hr reperfusion), esmolol, milrinone or esmolol + milrinone were intravenous (IV) infused over 10 min (from the last 5min of ischemia to the first 5min of reperfusion). LV-I...

  9. A partially ionized plasma modeling; Un modele de plasma partiellement ionise

    Energy Technology Data Exchange (ETDEWEB)

    Le Thanh, K.C.; Raviart, P.A

    2003-07-01

    We propose a model for the partially ionized plasma sheaths near the anode of an anodic spot electric arc where the cathode is considered as an electron emitter. A fluid description takes into account the heating and the ionization of the plasma induced by the electron beam. As physical hypothesis we assume that the condition of charge neutrality is valid. According that the electron mass can be neglected compared to the ion mass, we can assume that ions and atoms have the same velocity and the same temperature. Electrons and heavy particles are then regarded as two separate fluids coexisting in the plasma. Governing equations are then multi-fluid equations with relaxation correction to the local thermodynamic equilibrium (LTE) and heating by Joule effect. Equations are solved by an operator splitting procedure. That is we first discretize the homogeneous conservation laws (i.e. without source terms) by a finite volume method. The second step is to solve the ordinary differential system (i.e, governing equation without transport terms) with an implicit scheme. (authors)

  10. Transplantation of Rat Mesenchymal Stem Cells Overexpressing Hypoxia-Inducible Factor 2α Improves Blood Perfusion and Arteriogenesis in a Rat Hindlimb Ischemia Model

    Directory of Open Access Journals (Sweden)

    Weifeng Lu

    2017-01-01

    Full Text Available Mesenchymal stem cells (MSCs have been increasingly tested in cell-based therapy to treat numerous diseases. Genetic modification to improve MSC behavior may enhance posttransplantation outcome. This study aims to test the potential therapeutic benefits of rat bone marrow MSCs overexpressing hypoxia-inducible factor 2α (rMSCsHIF-2α in a rat hindlimb ischemia model. PBS, rMSCs, or rMSCsHIF-2α were injected into rat ischemic hindlimb. Compared with the injection of PBS or rMSCs, transplantation of rMSCsHIF-2α significantly improved blood perfusion, increased the number of vessel branches in the muscle of the ischemic hindlimb, and improved the foot mobility of the ischemic hindlimb (all P<0.05. rMSCHIF-2α transplantation also markedly increased the expression of proangiogenic factors VEGF, bFGF, and SDF1 and Notch signaling proteins including DII4, NICD, Hey1, and Hes1, whereas it reduced the expression of proapoptotic factor Bax in the muscle of the ischemic hindlimb. Overexpression of HIF-2α did not affect rMSC stemness and proliferation under normoxia but significantly increased rMSC migration and tube formation in matrigel under hypoxia (all P<0.05. RMSCsHIF-2α stimulated endothelial cell invasion under hypoxia significantly (P<0.05. Genetic modification of rMSCs via overexpression of HIF-2α improves posttransplantation outcomes in a rat hindlimb ischemia model possibly by stimulating proangiogenic growth factors and cytokines.

  11. Regulation of Expression of Renal Organic Anion Transporters OAT1 and OAT3 in a Model of Ischemia/Reperfusion Injury

    Directory of Open Access Journals (Sweden)

    Christina Preising

    2015-08-01

    Full Text Available Background: Recently, we gained evidence that impairment of rOat1 and rOat3 expression induced by ischemic acute kidney injury (AKI is mediated by COX metabolites and this suppression might be critically involved in renal damage. Methods: (i Basolateral organic anion uptake into proximal tubular cells after model ischemia and reperfusion (I/R was investigated by fluorescein uptake. The putative promoter sequences from hOAT1 (SLC22A6 and hOAT3 (SCL22A8 were cloned into a reporter plasmid, transfected into HEK cells and (ii transcriptional activity was determined after model ischemia and reperfusion as a SEAP reporter gen assay. Inhibitors or antagonists were applied with the beginning of reperfusion. Results: By using inhibitors of PKA (H89 and PLC (U73122, antagonists of E prostanoid receptor type 2 (AH6809 and type 4 (L161,982, we gained evidence that I/R induced down regulation of organic anion transport is mediated by COX1 metabolites via E prostanoid receptor type 4. The latter signaling was confirmed by application of butaprost (EP2 agonist or TCS2510 (EP4 agonist to control cells. In brief, the latter signaling was verified for the transcriptional activity in the reporter gen assay established. Therein, selective inhibitors for COX1 (SC58125 and COX2 (SC560 were also applied. Conclusion: Our data show (a that COX1 metabolites are involved in the regulation of renal organic anion transport(ers after I/R via the EP4 receptor and (b that this is due to transcriptional regulation of the respective transporters. As the promoter sequences cloned were of human origin and expressed in a human renal epithelial cell line we (c hypothesize that the regulatory mechanisms described after I/R is meaningful for humans as well.

  12. Selection of reference genes in different myocardial regions of an in vivo ischemia/reperfusion rat model for normalization of antioxidant gene expression

    Directory of Open Access Journals (Sweden)

    Vesentini Nicoletta

    2012-02-01

    Full Text Available Abstract Background Changes in cardiac gene expression due to myocardial injury are usually assessed in whole heart tissue. However, as the heart is a heterogeneous system, spatial and temporal heterogeneity is expected in gene expression. Results In an ischemia/reperfusion (I/R rat model we evaluated gene expression of mitochondrial and cytoplasmatic superoxide dismutase (MnSod, Cu-ZnSod and thioredoxin reductase (trxr1 upon short (4 h and long (72 h reperfusion times in the right ventricle (RV, and in the ischemic/reperfused (IRR and the remote region (RR of the left ventricle. Gene expression was assessed by Real-time reverse-transcription quantitative PCR (RT-qPCR. In order to select most stable reference genes suitable for normalization purposes, in each myocardial region we tested nine putative reference genes by geNorm analysis. The genes investigated were: Actin beta (actb, Glyceraldehyde-3-P-dehydrogenase (gapdh, Ribosomal protein L13A (rpl13a, Tyrosine 3-monooxygenase (ywhaz, Beta-glucuronidase (gusb, Hypoxanthine guanine Phosphoribosyltransferase 1 (hprt, TATA binding box protein (tbp, Hydroxymethylbilane synthase (hmbs, Polyadenylate-binding protein 1 (papbn1. According to our findings, most stable reference genes in the RV and RR were hmbs/hprt and hmbs/tbp/hprt respectively. In the IRR, six reference genes were recommended for normalization purposes; however, in view of experimental feasibility limitations, target gene expression could be normalized against the three most stable reference genes (ywhaz/pabp/hmbs without loss of sensitivity. In all cases MnSod and Cu-ZnSod expression decreased upon long reperfusion, the former in all myocardial regions and the latter in IRR alone. trxr1 expression did not vary. Conclusions This study provides a validation of reference genes in the RV and in the anterior and posterior wall of the LV of cardiac ischemia/reperfusion model and shows that gene expression should be assessed separately in

  13. Consequences of the genetic threshold model for observing partial migration under climate change scenarios.

    Science.gov (United States)

    Cobben, Marleen M P; van Noordwijk, Arie J

    2017-10-01

    Migration is a widespread phenomenon across the animal kingdom as a response to seasonality in environmental conditions. Partially migratory populations are populations that consist of both migratory and residential individuals. Such populations are very common, yet their stability has long been debated. The inheritance of migratory activity is currently best described by the threshold model of quantitative genetics. The inclusion of such a genetic threshold model for migratory behavior leads to a stable zone in time and space of partially migratory populations under a wide range of demographic parameter values, when assuming stable environmental conditions and unlimited genetic diversity. Migratory species are expected to be particularly sensitive to global warming, as arrival at the breeding grounds might be increasingly mistimed as a result of the uncoupling of long-used cues and actual environmental conditions, with decreasing reproduction as a consequence. Here, we investigate the consequences for migratory behavior and the stability of partially migratory populations under five climate change scenarios and the assumption of a genetic threshold value for migratory behavior in an individual-based model. The results show a spatially and temporally stable zone of partially migratory populations after different lengths of time in all scenarios. In the scenarios in which the species expands its range from a particular set of starting populations, the genetic diversity and location at initialization determine the species' colonization speed across the zone of partial migration and therefore across the entire landscape. Abruptly changing environmental conditions after model initialization never caused a qualitative change in phenotype distributions, or complete extinction. This suggests that climate change-induced shifts in species' ranges as well as changes in survival probabilities and reproductive success can be met with flexibility in migratory behavior at the

  14. Structural adaptation to ischemia in skeletal muscle: effects of blockers of the renin-angiotensin system

    NARCIS (Netherlands)

    Scheidegger, K. J.; Nelissen-Vrancken, M. H.; Leenders, P. J.; Daemen, M. J.; Smits, J. F.; Wood, J. M.

    1997-01-01

    To investigate the effects of long-term treatment with blockers of the renin-angiotensin system on capillarization and growth of fibers in ischemic hind-limb muscles and in muscles under normal growth conditions. Ischemia was induced by partial ligation of the left common iliac artery. Ischemia

  15. Lattice Boltzmann model for high-order nonlinear partial differential equations

    Science.gov (United States)

    Chai, Zhenhua; He, Nanzhong; Guo, Zhaoli; Shi, Baochang

    2018-01-01

    In this paper, a general lattice Boltzmann (LB) model is proposed for the high-order nonlinear partial differential equation with the form ∂tϕ +∑k=1mαk∂xkΠk(ϕ ) =0 (1 ≤k ≤m ≤6 ), αk are constant coefficients, Πk(ϕ ) are some known differential functions of ϕ . As some special cases of the high-order nonlinear partial differential equation, the classical (m)KdV equation, KdV-Burgers equation, K (n ,n ) -Burgers equation, Kuramoto-Sivashinsky equation, and Kawahara equation can be solved by the present LB model. Compared to the available LB models, the most distinct characteristic of the present model is to introduce some suitable auxiliary moments such that the correct moments of equilibrium distribution function can be achieved. In addition, we also conducted a detailed Chapman-Enskog analysis, and found that the high-order nonlinear partial differential equation can be correctly recovered from the proposed LB model. Finally, a large number of simulations are performed, and it is found that the numerical results agree with the analytical solutions, and usually the present model is also more accurate than the existing LB models [H. Lai and C. Ma, Sci. China Ser. G 52, 1053 (2009), 10.1007/s11433-009-0149-3; H. Lai and C. Ma, Phys. A (Amsterdam) 388, 1405 (2009), 10.1016/j.physa.2009.01.005] for high-order nonlinear partial differential equations.

  16. Lattice Boltzmann model for high-order nonlinear partial differential equations.

    Science.gov (United States)

    Chai, Zhenhua; He, Nanzhong; Guo, Zhaoli; Shi, Baochang

    2018-01-01

    In this paper, a general lattice Boltzmann (LB) model is proposed for the high-order nonlinear partial differential equation with the form ∂_{t}ϕ+∑_{k=1}^{m}α_{k}∂_{x}^{k}Π_{k}(ϕ)=0 (1≤k≤m≤6), α_{k} are constant coefficients, Π_{k}(ϕ) are some known differential functions of ϕ. As some special cases of the high-order nonlinear partial differential equation, the classical (m)KdV equation, KdV-Burgers equation, K(n,n)-Burgers equation, Kuramoto-Sivashinsky equation, and Kawahara equation can be solved by the present LB model. Compared to the available LB models, the most distinct characteristic of the present model is to introduce some suitable auxiliary moments such that the correct moments of equilibrium distribution function can be achieved. In addition, we also conducted a detailed Chapman-Enskog analysis, and found that the high-order nonlinear partial differential equation can be correctly recovered from the proposed LB model. Finally, a large number of simulations are performed, and it is found that the numerical results agree with the analytical solutions, and usually the present model is also more accurate than the existing LB models [H. Lai and C. Ma, Sci. China Ser. G 52, 1053 (2009)1672-179910.1007/s11433-009-0149-3; H. Lai and C. Ma, Phys. A (Amsterdam) 388, 1405 (2009)PHYADX0378-437110.1016/j.physa.2009.01.005] for high-order nonlinear partial differential equations.

  17. A genetic model of progressively partial melting for uranium-bearing granites in south China

    International Nuclear Information System (INIS)

    Zhai Jianping.

    1989-01-01

    A genetic model of progressively partial and enrichment mechanism of uranium during partial melting of the sources of material studied and the significance of the genetic model in search of uranium deposits is elaborated. This model accounts better for some geological and geochemical features of uranium-bearing granties and suspects the traditional idea that igneous uranium-bearing granites were formed by fusion of U-rich strata surrounding these granites. Finally this paper points out that the infuence of U-rich strata of wall rocks of granites over uranium-bearing granites depends on variation of water solubility in the magma and assimilation of magma to wall rocks during its ascending and crystallization

  18. Comparison of annual maximum series and partial duration series methods for modeling extreme hydrologic events

    DEFF Research Database (Denmark)

    Madsen, Henrik; Rasmussen, Peter F.; Rosbjerg, Dan

    1997-01-01

    Two different models for analyzing extreme hydrologic events, based on, respectively, partial duration series (PDS) and annual maximum series (AMS), are compared. The PDS model assumes a generalized Pareto distribution for modeling threshold exceedances corresponding to a generalized extreme value......). In the case of ML estimation, the PDS model provides the most efficient T-year event estimator. In the cases of MOM and PWM estimation, the PDS model is generally preferable for negative shape parameters, whereas the AMS model yields the most efficient estimator for positive shape parameters. A comparison...... of the considered methods reveals that in general, one should use the PDS model with MOM estimation for negative shape parameters, the PDS model with exponentially distributed exceedances if the shape parameter is close to zero, the AMS model with MOM estimation for moderately positive shape parameters, and the PDS...

  19. Experimental Focal Cerebral Ischemia

    DEFF Research Database (Denmark)

    Christensen, Thomas

    2007-01-01

    Focal cerebral ischemia due to occlusion of a major cerebral artery is the cause of ischemic stroke which is a major reason of mortality, morbidity and disability in the populations of the developed countries. In the seven studies summarized in the thesis focal ischemia in rats induced by occlusion...... in the penumbra is recruited in the infarction process leading to a progressive growth of the infarct. The penumbra hence constitutes an important target for pharmacological treatment because of the existence of a therapeutic time window during which treatment with neuroprotective compounds may prevent...

  20. Benefits and limitations of animal models in partial bladder outlet obstruction for translational research.

    Science.gov (United States)

    Kitta, Takeya; Kanno, Yukiko; Chiba, Hiroki; Higuchi, Madoka; Ouchi, Mifuka; Togo, Mio; Moriya, Kimihiko; Shinohara, Nobuo

    2018-01-01

    The functions of the lower urinary tract have been investigated for more than a century. Lower urinary tract symptoms, such as incomplete bladder emptying, weak urine stream, daytime urinary frequency, urgency, urge incontinence and nocturia after partial bladder outlet obstruction, is a frequent cause of benign prostatic hyperplasia in aging men. However, the pathophysiological mechanisms have not been fully elucidated. The use of animal models is absolutely imperative for understanding the pathophysiological processes involved in bladder dysfunction. Surgical induction has been used to study lower urinary tract functions of numerous animal species, such as pig, dog, rabbit, guinea pig, rat and mouse, of both sexes. Several morphological and functional modifications under partial bladder outlet obstruction have not only been observed in the bladder, but also in the central nervous system. Understanding the changes of the lower urinary tract functions induced by partial bladder outlet obstruction would also contribute to appropriate drug development for treating these pathophysiological conditions. In the present review, we discuss techniques for creating partial bladder outlet obstruction, the characteristics of several species, as well as issues of each model, and their translational value. © 2017 The Japanese Urological Association.

  1. Inventory Model with Partial Backordering When Backordered Customers Delay Purchase after Stockout-Restoration

    Directory of Open Access Journals (Sweden)

    Ren-Qian Zhang

    2016-01-01

    Full Text Available Many inventory models with partial backordering assume that the backordered demand must be filled instantly after stockout restoration. In practice, however, the backordered customers may successively revisit the store because of the purchase delay behavior, producing a limited backorder demand rate and resulting in an extra inventory holding cost. Hence, in this paper we formulate the inventory model with partial backordering considering the purchase delay of the backordered customers and assuming that the backorder demand rate is proportional to the remaining backordered demand. Particularly, we model the problem by introducing a new inventory cost component of holding the backordered items, which has not been considered in the existing models. We propose an algorithm with a two-layer structure based on Lipschitz Optimization (LO to minimize the total inventory cost. Numerical experiments show that the proposed algorithm outperforms two benchmarks in both optimality and efficiency. We also observe that the earlier the backordered customer revisits the store, the smaller the inventory cost and the fill rate are, but the longer the order cycle is. In addition, if the backordered customers revisit the store without too much delay, the basic EOQ with partial backordering approximates our model very well.

  2. Protease-activated receptor (PAR2, but not PAR1, is involved in collateral formation and anti-inflammatory monocyte polarization in a mouse hind limb ischemia model.

    Directory of Open Access Journals (Sweden)

    Lisa G van den Hengel

    Full Text Available AIMS: In collateral development (i.e. arteriogenesis, mononuclear cells are important and exist as a heterogeneous population consisting of pro-inflammatory and anti-inflammatory/repair-associated cells. Protease-activated receptor (PAR1 and PAR2 are G-protein-coupled receptors that are both expressed by mononuclear cells and are involved in pro-inflammatory reactions, while PAR2 also plays a role in repair-associated responses. Here, we investigated the physiological role of PAR1 and PAR2 in arteriogenesis in a murine hind limb ischemia model. METHODS AND RESULTS: PAR1-deficient (PAR1-/-, PAR2-deficient (PAR2-/- and wild-type (WT mice underwent femoral artery ligation. Laser Doppler measurements revealed reduced post-ischemic blood flow recovery in PAR2-/- hind limbs when compared to WT, while PAR1-/- mice were not affected. Upon ischemia, reduced numbers of smooth muscle actin (SMA-positive collaterals and CD31-positive capillaries were found in PAR2-/- mice when compared to WT mice, whereas these parameters in PAR1-/- mice did not differ from WT mice. The pool of circulating repair-associated (Ly6C-low monocytes and the number of repair-associated (CD206-positive macrophages surrounding collaterals in the hind limbs were increased in WT and PAR1-/- mice, but unaffected in PAR2-/- mice. The number of repair-associated macrophages in PAR2-/- hind limbs correlated with CD11b- and CD115-expression on the circulating monocytes in these animals, suggesting that monocyte extravasation and M-CSF-dependent differentiation into repair-associated cells are hampered. CONCLUSION: PAR2, but not PAR1, is involved in arteriogenesis and promotes the repair-associated response in ischemic tissues. Therefore, PAR2 potentially forms a new pro-arteriogenic target in coronary artery disease (CAD patients.

  3. The rare sugar D-allose has a reducing effect against ischemia-reperfusion injury on the rat abdominal skin island flap model.

    Science.gov (United States)

    Muneuchi, Gan; Hossain, Akram; Yamaguchi, Fuminori; Ueno, Masaki; Tanaka, Yoshio; Suzuki, Shigehiko; Tokuda, Masaaki

    2013-08-01

    Recently, one of the rare sugars, D-allose, has received attention from many researchers because of its availability for mass production and its various physiological functions. Among these, an antioxidative effect has been strongly suggested. In this study, we investigated whether this effect is also applicable to the field of skin surgery. In ischemia-reperfusion injury model using the rat abdominal skin island flap (male Wistar rats, n = 110), D-allose was injected intravenously 15 min before 8-h ischemia. The survival area (%) was measured by digital photographic assessment 1 wk after surgery, and multiple comparisons (Fisher's protected least significant difference) were carried out. Histopathological examination (neutrophilic infiltration into dermis in hematoxylin and eosin stain) and immunostaining (of ectodermal dysplasia-1 (ED1)-positive cells/flap) were assessed. Myeloperoxidase (MPO) activity in the skin flap (sampling at the time of 8 h after reperfusion) was measured spectrophotometrically, and Student t-test was performed. D-allose extended the survival of the remaining flaps, and a dose greater than 30 mg (0.1 mg/g) was necessary to be effective. The flap survival rates in the 30, 60, and 150 mg groups were significantly higher than that in the control (saline) group: 75.87 ± 5.90, 79.27 ± 7.81, and 77.87 ± 6.20 versus 50.53 ± 9.66, respectively (P rare sugars are safer for our bodies as well as the environment; therefore, this rare sugar project is expected to lead to the development of a safer antioxidant for skin flap surgery. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. Exogenous surfactant application in a rat lung ischemia reperfusion injury model: effects on edema formation and alveolar type II cells

    Directory of Open Access Journals (Sweden)

    Richter Joachim

    2008-01-01

    Full Text Available Abstract Background Prophylactic exogenous surfactant therapy is a promising way to attenuate the ischemia and reperfusion (I/R injury associated with lung transplantation and thereby to decrease the clinical occurrence of acute lung injury and acute respiratory distress syndrome. However, there is little information on the mode by which exogenous surfactant attenuates I/R injury of the lung. We hypothesized that exogenous surfactant may act by limiting pulmonary edema formation and by enhancing alveolar type II cell and lamellar body preservation. Therefore, we investigated the effect of exogenous surfactant therapy on the formation of pulmonary edema in different lung compartments and on the ultrastructure of the surfactant producing alveolar epithelial type II cells. Methods Rats were randomly assigned to a control, Celsior (CE or Celsior + surfactant (CE+S group (n = 5 each. In both Celsior groups, the lungs were flush-perfused with Celsior and subsequently exposed to 4 h of extracorporeal ischemia at 4°C and 50 min of reperfusion at 37°C. The CE+S group received an intratracheal bolus of a modified natural bovine surfactant at a dosage of 50 mg/kg body weight before flush perfusion. After reperfusion (Celsior groups or immediately after sacrifice (Control, the lungs were fixed by vascular perfusion and processed for light and electron microscopy. Stereology was used to quantify edematous changes as well as alterations of the alveolar epithelial type II cells. Results Surfactant treatment decreased the intraalveolar edema formation (mean (coefficient of variation: CE: 160 mm3 (0.61 vs. CE+S: 4 mm3 (0.75; p 3 (0.90 vs. CE+S: 0 mm3; p 3 (0.39 vs. CE+S: 268 mm3 (0.43; p 3(0.10 and CE+S (481 μm3(0.10 compared with controls (323 μm3(0.07; p Conclusion Intratracheal surfactant application before I/R significantly reduces the intraalveolar edema formation and development of atelectases but leads to an increased development of

  5. Partially linear mixed-effects joint models for skewed and missing longitudinal competing risks outcomes.

    Science.gov (United States)

    Lu, Tao; Lu, Minggen; Wang, Min; Zhang, Jun; Dong, Guang-Hui; Xu, Yong

    2017-12-18

    Longitudinal competing risks data frequently arise in clinical studies. Skewness and missingness are commonly observed for these data in practice. However, most joint models do not account for these data features. In this article, we propose partially linear mixed-effects joint models to analyze skew longitudinal competing risks data with missingness. In particular, to account for skewness, we replace the commonly assumed symmetric distributions by asymmetric distribution for model errors. To deal with missingness, we employ an informative missing data model. The joint models that couple the partially linear mixed-effects model for the longitudinal process, the cause-specific proportional hazard model for competing risks process and missing data process are developed. To estimate the parameters in the joint models, we propose a fully Bayesian approach based on the joint likelihood. To illustrate the proposed model and method, we implement them to an AIDS clinical study. Some interesting findings are reported. We also conduct simulation studies to validate the proposed method.

  6. Interstitial pO2 in ischemic penumbra and core are differentially affected following transient focal cerebral ischemia in rats.

    Science.gov (United States)

    Liu, Shimin; Shi, Honglian; Liu, Wenlan; Furuichi, Takamitsu; Timmins, Graham S; Liu, Ke Jian

    2004-03-01

    Stroke causes heterogeneous changes in tissue oxygenation, with a region of decreased blood flow, the penumbra, surrounding a severely damaged ischemic core. Treatment of acute ischemic stroke aims to save this penumbra before its irreversible damage by continued ischemia. However, effective treatment remains elusive due to incomplete understanding of processes leading to penumbral death. While oxygenation is central in ischemic neuronal death, it is unclear exactly what actual changes occur in interstitial oxygen tension (pO2) in ischemic regions during stroke, particularly the penumbra. Using the unique capability of in vivo electron paramagnetic resonance (EPR) oximetry to measure localized interstitial pO2, we measured both absolute values, and temporal changes of pO2 in ischemic penumbra and core during ischemia and reperfusion in a rat model. Ischemia rapidly decreased interstitial pO2 to 32% +/- 7.6% and 4% +/- 0.6% of pre-ischemic values in penumbra and core, respectively 1 hour after ischemia. Importantly, whilst reperfusion restored core pO2 close to its pre-ischemic value, penumbral pO2 only partially recovered. Hyperoxic treatment significantly increased penumbral pO2 during ischemia, but not in the core, and also increased penumbral pO2 during reperfusion. These divergent, important changes in pO2 in penumbra and core were explained by combined differences in cellular oxygen consumption rates and microcirculation conditions. We therefore demonstrate that interstitial pO2 in penumbra and core is differentially affected during ischemia and reperfusion, providing new insights to the pathophysiology of stroke. The results support normobaric hyperoxia as a potential early intervention to save penumbral tissue in acute ischemic stroke.

  7. Sympathetic nerve damage and restoration after ischemia-reperfusion injury as assessed by {sup 11}C-hydroxyephedrine

    Energy Technology Data Exchange (ETDEWEB)

    Werner, Rudolf A.; Higuchi, Takahiro [University of Wuerzburg, Department of Nuclear Medicine, Wuerzburg (Germany); University of Wuerzburg, Comprehensive Heart Failure Center, Wuerzburg (Germany); Maya, Yoshifumi [University of Wuerzburg, Department of Nuclear Medicine, Wuerzburg (Germany); Nihon Medi-Physics Co., Ltd., Research Centre, Chiba (Japan); Rischpler, Christoph [Technische Universitaet Muenchen, Department of Nuclear Medicine, Klinikum rechts der Isar, Muenchen (Germany); Javadi, Mehrbod S. [Johns Hopkins University, Division of Nuclear Medicine, Russell H. Morgan Department of Radiology, Baltimore, MD (United States); Fukushima, Kazuhito [Hyogo College of Medicine, Department of Radiology, Hyogo (Japan); Lapa, Constantin [University of Wuerzburg, Department of Nuclear Medicine, Wuerzburg (Germany); Herrmann, Ken [University of Wuerzburg, Department of Nuclear Medicine, Wuerzburg (Germany); David Geffen School of Medicine at UCLA, Department of Molecular and Medical Pharmacology, Los Angeles, CA (United States)

    2016-02-15

    An altered state of the cardiac sympathetic nerves is an important prognostic factor in patients with coronary artery disease. The aim of this study was to investigate regional sympathetic nerve damage and restoration utilizing a rat model of myocardial transient ischemia and a catecholamine analog PET tracer, {sup 11}C-hydroxyephedrine ({sup 11}C-HED). Transient myocardial ischemia was induced by coronary occlusion for 20 min and reperfusion in male Wistar rats. Dual-tracer autoradiography was performed subacutely (7 days) and chronically (2 months) after ischemia, and in control rats without ischemia using {sup 11}C-HED as a marker of sympathetic innervation and {sup 201}TI for perfusion. Additional serial in vivo cardiac {sup 11}C-HED and {sup 18}F-FDG PET scans were performed in the subacute and chronic phases after ischemia. After transient ischemia, the {sup 11}C-HED uptake defect areas in both the subacute and chronic phases were clearly larger than the perfusion defect areas in the midventricular wall. The subacute {sup 11}C-HED uptake defect showed a transmural pattern, whereas uptake recovered in the subepicardial portion in the chronic phase. Tyrosine hydroxylase antibody nerve staining confirmed regional denervation corresponding to areas of decreased {sup 11}C-HED uptake. Serial in vivo PET imaging visualized reductions in the area of the {sup 11}C-HED uptake defects in the chronic phase consistent with autoradiography and histology. Higher susceptibility of sympathetic neurons compared to myocytes was confirmed by a larger {sup 11}C-HED defect with a corresponding histologically identified region of denervation. Furthermore, partial reinnervation was observed in the chronic phase as shown by recovery of subepicardial {sup 11}C-HED uptake. (orig.)

  8. A lattice Boltzmann model with an amending function for simulating nonlinear partial differential equations

    International Nuclear Information System (INIS)

    Lin-Jie, Chen; Chang-Feng, Ma

    2010-01-01

    This paper proposes a lattice Boltzmann model with an amending function for one-dimensional nonlinear partial differential equations (NPDEs) in the form u t + αuu x + βu n u x + γu xx + δu xxx + ζu xxxx = 0. This model is different from existing models because it lets the time step be equivalent to the square of the space step and derives higher accuracy and nonlinear terms in NPDEs. With the Chapman–Enskog expansion, the governing evolution equation is recovered correctly from the continuous Boltzmann equation. The numerical results agree well with the analytical solutions. (general)

  9. Unidimensional factor models imply weaker partial correlations than zero-order correlations.

    Science.gov (United States)

    van Bork, Riet; Grasman, Raoul P P P; Waldorp, Lourens J

    2018-06-01

    In this paper we present a new implication of the unidimensional factor model. We prove that the partial correlation between two observed variables that load on one factor given any subset of other observed variables that load on this factor lies between zero and the zero-order correlation between these two observed variables. We implement this result in an empirical bootstrap test that rejects the unidimensional factor model when partial correlations are identified that are either stronger than the zero-order correlation or have a different sign than the zero-order correlation. We demonstrate the use of the test in an empirical data example with data consisting of fourteen items that measure extraversion.

  10. Modeling of a partially debonded piezoelectric actuator in smart composite laminates

    International Nuclear Information System (INIS)

    Huang, Bin; Soo Kim, Heung; Ho Yoon, Gil

    2015-01-01

    A partially debonded piezoelectric actuator in smart composite laminates was modeled using an improved layerwise displacement field and Heaviside unit step functions. The finite element method with four node plate element and the extended Hamilton principle were used to derive the governing equation. The effects of actuator debonding on the smart composite laminate were investigated in both the frequency and time domains. The frequency and transient responses were obtained using the mode superposition method and the Newmark time integration algorithm, respectively. Two partial actuator debonding cases were studied to investigate the debonding effects on the actuation capability of the piezoelectric actuator. The effect of actuator debonding on the natural frequencies was subtler, but severe reductions of the actuation ability were observed in both the frequency and time responses, especially in the edge debonded actuator case. The results provided confirmation that the proposed modeling could be used in virtual experiments of actuator failure in smart composite laminates. (paper)

  11. The metabolism of 15-p-[123I]-iodophenylpentadecanoic acid in a surgically induced canine model of regional ischemia

    International Nuclear Information System (INIS)

    Hudon, M.P.J.; Jamieson, W.R.E.; Qayumi, A.K.; Lyster, D.M.; Sartori, C.; Dougan, H.

    1990-01-01

    The purpose of this study was to examine the longitudinal effect of gradual coronary occlusion on regional myocardial metabolism of 15-p- 123 I-iodophenyl pentadecanoic acid ([ 123 I]IPPA). Adult dogs were images using [ 123 I]IPPA and planar gamma imaging. A thoracotomy as performed and an ameroid constricter of appropriate size permanently positioned on the left anterior descending artery. The dogs were imaged after injection of 3-5 mCi [ 123 I]IPPA at various times over a 2-week period. With imaging on days 7 and 14, the dogs were paced at a rate of 185. Time-activity curves were generated and t 1/2 values calculated using monoexponential curve fitting. Results indicate a significant increase in t 1/2 between control and 14 days after surgery in the apical wall (29±7 to 53±18 min; P 1/2 in the lateral wall, this was not significant (27±8 to 78±99 min; P>0.05). There was no significant change in t 1/2 in the septal wall (27±9 to 33±8 min; P>0.05). We conclude that [ 123 I]IPPA is a useful indicator of developing myocardial ischemia. (orig.)

  12. Intraarterial route increases the risk of cerebral lesions after mesenchymal cell administration in animal model of ischemia

    Science.gov (United States)

    Argibay, Bárbara; Trekker, Jesse; Himmelreich, Uwe; Beiras, Andrés; Topete, Antonio; Taboada, Pablo; Pérez-Mato, María; Vieites-Prado, Alba; Iglesias-Rey, Ramón; Rivas, José; Planas, Anna M.; Sobrino, Tomás; Castillo, José; Campos, Francisco

    2017-01-01

    Mesenchymal stem cells (MSCs) are a promising clinical therapy for ischemic stroke. However, critical parameters, such as the most effective administration route, remain unclear. Intravenous (i.v.) and intraarterial (i.a.) delivery routes have yielded varied outcomes across studies, potentially due to the unknown MSCs distribution. We investigated whether MSCs reached the brain following i.a. or i.v. administration after transient cerebral ischemia in rats, and evaluated the therapeutic effects of both routes. MSCs were labeled with dextran-coated superparamagnetic nanoparticles for magnetic resonance imaging (MRI) cell tracking, transmission electron microscopy and immunohistological analysis. MSCs were found in the brain following i.a. but not i.v. administration. However, the i.a. route increased the risk of cerebral lesions and did not improve functional recovery. The i.v. delivery is safe but MCS do not reach the brain tissue, implying that treatment benefits observed for this route are not attributable to brain MCS engrafting after stroke.

  13. The metabolism of 15-p-[123I]-iodophenylpentadecanoic acid in a surgically induced canine model of regional ischemia.

    Science.gov (United States)

    Hudon, M P; Lyster, D M; Jamieson, W R; Qayumi, A K; Sartori, C; Dougan, H

    1990-01-01

    The purpose of this study was to examine the longitudinal effect of gradual coronary occlusion on regional myocardial metabolism of 15-p-123I-iodophenylpentadecanoic acid [( 123I]IPPA). Adult dogs were imaged using [123I]IPPA and planar gamma imaging. A thoracotomy was performed and an ameroid constrictor of appropriate size permanently positioned on the left anterior descending coronary artery. The dogs were imaged after injection of 3-5 mCi [123I]IPPA at various times over a 2-week period. With imaging on days 7 and 14, the dogs were paced at a rate of 185. Time-activity curves were generated and t1/2 values calculated using monoexponential curve fitting. Results indicate a significant increase in t1/2 between control and 14 days after surgery in the apical wall (29 +/- 7 to 53 +/- 18 min; P less than 0.05). Although there was also an increased t1/2 in the lateral wall, this was not significant (27 +/- 8 to 78 +/- 99 min; P greater than 0.05). There was no significant change in t1/2 in the septal wall (27 +/- 9 to 33 +/- 8 min; P greater than 0.05). We conclude that [123I]IPPA is a useful indicator of developing myocardial ischemia.

  14. Migraine and ischemia

    NARCIS (Netherlands)

    van der Wammes-van der Heijden, E.A.

    2009-01-01

    An association between migraine and ischemic events, especially ischemic stroke, has been debated for many years. Whether migraine is a risk factor for ischemic events or ischemia triggers migraine, or both, is still unclear. This thesis explores different relationships between migraine and

  15. Mathematical Modeling of Partial-Porous Circular Cylinders with Water Waves

    Directory of Open Access Journals (Sweden)

    Min-Su Park

    2015-01-01

    Full Text Available The interaction of water waves with partially porous-surfaced circular cylinders was investigated. A three-dimensional numerical modeling was developed based on the complete mathematical formulation of the eigenfunction expansion method in the potential flow. Darcy’s law was applied to describe the porous boundary. The partial-porous cylinder is composed of a porous-surfaced body near the free surface, and an impermeable-surfaced body with an end-capped rigid bottom below the porous region. The optimal ratio of the porous portion to the impermeable portion can be adopted to design an effective ocean structure with minimal hydrodynamic impact. To scrutinize the hydrodynamic interactions in N partial-porous circular cylinders, the computational fluid domain is divided into three regions: an exterior region, N inner porous body regions, and N regions beneath the body. Wave excitation forces and wave run-up on multibodied partial-porous cylinders are calculated and compared for various porous-portion ratios and wave conditions, all of which significantly influence the hydrodynamic property.

  16. Modelling and investigation of partial wetting surfaces for drop dynamics using lattice Boltzmann method

    Energy Technology Data Exchange (ETDEWEB)

    Pravinraj, T., E-mail: pravinraj1711@gmail.com; Patrikar, Rajendra

    2017-07-01

    Highlights: • A LBM model on partial wetting surface for droplet dynamics is presented by introducing a simple initial partial wetting boundary condition in SC model. • With our approach one can tune the splitting volume and time by carefully choosing strip width and position. • It is shown that the droplet spreading on chemically heterogeneous surfaces can be controlled not only by Weber number but also by tuning strip width ratio. • The directional transportation of a droplet due to chemical wetting gradient is simulated and analyzed using hybrid thermodynamic-image processing technique. • Microstructure surface and its influence on the directional wetting based transportation of droplet are demonstrated. - Abstract: Partial wetting surfaces and its influence on the droplet movement of micro and nano scale being contemplated for many useful applications. The dynamics of the droplet usually analyzed with a multiphase lattice Boltzmann method (LBM). In this paper, the influence of partial wetting surface on the dynamics of droplet is systematically analyzed for various cases. Splitting of droplets due to chemical gradient of the surface is studied and analyses of splitting time for various widths of the strips for different Weber numbers are computed. With the proposed model one can tune the splitting volume and time by carefully choosing a strip width and droplet position. The droplet spreading on chemically heterogeneous surfaces shows that the spreading can be controlled not only by parameters of Weber number but also by tuning strip width ratio. The transportation of the droplet from hydrophobic surface to hydrophilic surface due to chemical gradient is simulated and analyzed using our hybrid thermodynamic-image processing technique. The results prove that with the progress of time the surface free energy decreases with increase in spreading area. Finally, the transportation of a droplet on microstructure gradient is demonstrated. The model explains

  17. A partial hearing animal model for chronic electro-acoustic stimulation

    Science.gov (United States)

    Irving, S.; Wise, A. K.; Millard, R. E.; Shepherd, R. K.; Fallon, J. B.

    2014-08-01

    Objective. Cochlear implants (CIs) have provided some auditory function to hundreds of thousands of people around the world. Although traditionally carried out only in profoundly deaf patients, the eligibility criteria for implantation have recently been relaxed to include many partially-deaf patients with useful levels of hearing. These patients receive both electrical stimulation from their implant and acoustic stimulation via their residual hearing (electro-acoustic stimulation; EAS) and perform very well. It is unclear how EAS improves speech perception over electrical stimulation alone, and little evidence exists about the nature of the interactions between electric and acoustic stimuli. Furthermore, clinical results suggest that some patients that undergo cochlear implantation lose some, if not all, of their residual hearing, reducing the advantages of EAS over electrical stimulation alone. A reliable animal model with clinically-relevant partial deafness combined with clinical CIs is important to enable these issues to be studied. This paper outlines such a model that has been successfully used in our laboratory. Approach. This paper outlines a battery of techniques used in our laboratory to generate, validate and examine an animal model of partial deafness and chronic CI use. Main results. Ototoxic deafening produced bilaterally symmetrical hearing thresholds in neonatal and adult animals. Electrical activation of the auditory system was confirmed, and all animals were chronically stimulated via adapted clinical CIs. Acoustic compound action potentials (CAPs) were obtained from partially-hearing cochleae, using the CI amplifier. Immunohistochemical analysis allows the effects of deafness and electrical stimulation on cell survival to be studied. Significance. This animal model has applications in EAS research, including investigating the functional interactions between electric and acoustic stimulation, and the development of techniques to maintain residual

  18. The Dif Identification in Constructed Response Items Using Partial Credit Model

    OpenAIRE

    Heri Retnawati

    2017-01-01

    The study was to identify the load, the type and the significance of differential item functioning (DIF) in constructed response item using the partial credit model (PCM). The data in the study were the students’ instruments and the students’ responses toward the PISA-like test items that had been completed by 386 ninth grade students and 460 tenth grade students who had been about 15 years old in the Province of Yogyakarta Special Region in Indonesia. The analysis toward the item characteris...

  19. Implicit particle filtering for models with partial noise, and an application to geomagnetic data assimilation

    Directory of Open Access Journals (Sweden)

    M. Morzfeld

    2012-06-01

    Full Text Available Implicit particle filtering is a sequential Monte Carlo method for data assimilation, designed to keep the number of particles manageable by focussing attention on regions of large probability. These regions are found by minimizing, for each particle, a scalar function F of the state variables. Some previous implementations of the implicit filter rely on finding the Hessians of these functions. The calculation of the Hessians can be cumbersome if the state dimension is large or if the underlying physics are such that derivatives of F are difficult to calculate, as happens in many geophysical applications, in particular in models with partial noise, i.e. with a singular state covariance matrix. Examples of models with partial noise include models where uncertain dynamic equations are supplemented by conservation laws with zero uncertainty, or with higher order (in time stochastic partial differential equations (PDE or with PDEs driven by spatially smooth noise processes. We make the implicit particle filter applicable to such situations by combining gradient descent minimization with random maps and show that the filter is efficient, accurate and reliable because it operates in a subspace of the state space. As an example, we consider a system of nonlinear stochastic PDEs that is of importance in geomagnetic data assimilation.

  20. Review on herbal medicine on brain ischemia and reperfusion简

    Institute of Scientific and Technical Information of China (English)

    Nahid; Jivad; Zahra; Rabiei

    2015-01-01

    Brain ischemia and reperfusion is the leading cause of serious and long-range disability in the world. Clinically significant changes in central nervous system function are observed following brain ischemia and reperfusion. Stroke patients exhibit behavioral, cognitive,emotional, affective and electrophysiological changes during recovery phase. Brain injury by transient complete global brain ischemia or by transient incomplete brain ischemia afflicts a very large number of patients in the world with death or permanent disability. In order to reduce this damage, we must sufficiently understand the mechanisms involved in brain ischemia and reperfusion and repair to design clinically effective therapy.Cerebral ischemia and reperfusion is known to induce the generation of reactive oxygen species that can lead to oxidative damage of proteins, membrane lipids and nucleic acids.A decrease in tissue antioxidant capacity, an increase in lipid peroxidation as well as an increase in lipid peroxidation inhibitors have been demonstrated in several models of brain ischemia. This paper reviews the number of commonly used types of herbal medicines effective for the treatment of stroke. The aim of this paper was to review evidences from controlled studies in order to discuss whether herbal medicine can be helpful in the treatment of brain ischemia and reperfusion.

  1. Generation of Chimeric “ABS Nanohemostat” Complex and Comparing Its Histomorphological In Vivo Effects to the Traditional Ankaferd Hemostat in Controlled Experimental Partial Nephrectomy Model

    Directory of Open Access Journals (Sweden)

    Emre Huri

    2013-01-01

    Full Text Available Purpose. Using the classical Ankaferd Blood Stopper (ABS solution to create active hemostasis during partial nephrectomy (PN may not be so effective due to insufficient contact surface between the ABS hemostatic liquid agent and the bleeding area. In order to broaden the contact surface, we generated a chimeric hemostatic agent, ABS nanohemostat, via combining a self-assembling peptide amphiphile molecule with the traditional Ankaferd hemostat. Materials and Methods. In order to generate ABS nanohemostat, a positively charged Peptide Amphiphile (PA molecule was synthesized by using solid phase peptide synthesis. For animal experiments, 24 Wistar rats were divided into the following 4 groups: Group 1: control; Group 2: conventional PN with only 0.5 ml Ankaferd hemostat; Group 3: conventional PN with ABS + peptide gel; Group 4: conventional PN with only 0.5 ml peptide solution. Results. Mean warm ischemia times (WITs were 232.8 ± 56.3, 65.6±11.4, 75.5± 17.2, and 58.1±17.6 seconds in Group 1 to Group 4, respectively. Fibrosis was not different among the groups, while inflammation was detected to be significantly different in G3 and G4. Conclusions. ABS nanohemostat has comparable hemostatic efficacy to the traditional Ankaferd hemostat in the partial nephrectomy experimental model. Elucidation of the cellular and tissue effects of this chimeric compound may establish a catalytic spark and open new avenues for novel experimental and clinical studies in the battlefield of hemostasis.

  2. Filtering a statistically exactly solvable test model for turbulent tracers from partial observations

    International Nuclear Information System (INIS)

    Gershgorin, B.; Majda, A.J.

    2011-01-01

    A statistically exactly solvable model for passive tracers is introduced as a test model for the authors' Nonlinear Extended Kalman Filter (NEKF) as well as other filtering algorithms. The model involves a Gaussian velocity field and a passive tracer governed by the advection-diffusion equation with an imposed mean gradient. The model has direct relevance to engineering problems such as the spread of pollutants in the air or contaminants in the water as well as climate change problems concerning the transport of greenhouse gases such as carbon dioxide with strongly intermittent probability distributions consistent with the actual observations of the atmosphere. One of the attractive properties of the model is the existence of the exact statistical solution. In particular, this unique feature of the model provides an opportunity to design and test fast and efficient algorithms for real-time data assimilation based on rigorous mathematical theory for a turbulence model problem with many active spatiotemporal scales. Here, we extensively study the performance of the NEKF which uses the exact first and second order nonlinear statistics without any approximations due to linearization. The role of partial and sparse observations, the frequency of observations and the observation noise strength in recovering the true signal, its spectrum, and fat tail probability distribution are the central issues discussed here. The results of our study provide useful guidelines for filtering realistic turbulent systems with passive tracers through partial observations.

  3. Model test on partial expansion in stratified subsidence during foundation pit dewatering

    Science.gov (United States)

    Wang, Jianxiu; Deng, Yansheng; Ma, Ruiqiang; Liu, Xiaotian; Guo, Qingfeng; Liu, Shaoli; Shao, Yule; Wu, Linbo; Zhou, Jie; Yang, Tianliang; Wang, Hanmei; Huang, Xinlei

    2018-02-01

    Partial expansion was observed in stratified subsidence during foundation pit dewatering. However, the phenomenon was suspected to be an error because the compression of layers is known to occur when subsidence occurs. A slice of the subsidence cone induced by drawdown was selected as the prototype. Model tests were performed to investigate the phenomenon. The underlying confined aquifer was generated as a movable rigid plate with a hinge at one end. The overlying layers were simulated with remolded materials collected from a construction site. Model tests performed under the conceptual model indicated that partial expansion occurred in stratified settlements under coordination deformation and consolidation conditions. During foundation pit dewatering, rapid drawdown resulted in rapid subsidence in the dewatered confined aquifer. The rapidly subsiding confined aquifer top was the bottom deformation boundary of the overlying layers. Non-coordination deformation was observed at the top and bottom of the subsiding overlying layers. The subsidence of overlying layers was larger at the bottom than at the top. The layers expanded and became thicker. The phenomenon was verified using numerical simulation method based on finite difference method. Compared with numerical simulation results, the boundary effect of the physical tests was obvious in the observation point close to the movable endpoint. The tensile stress of the overlying soil layers induced by the underlying settlement of dewatered confined aquifer contributed to the expansion phenomenon. The partial expansion of overlying soil layers was defined as inversed rebound. The inversed rebound was induced by inversed coordination deformation. Compression was induced by the consolidation in the overlying soil layers because of drainage. Partial expansion occurred when the expansion exceeded the compression. Considering the inversed rebound, traditional layer-wise summation method for calculating subsidence should be

  4. The Neuroprotective Effect of Kefir on Spinal Cord Ischemia/Reperfusion Injury in Rats

    Science.gov (United States)

    Akman, Tarik; Yener, Ali Umit; Sehitoglu, Muserref Hilal; Yuksel, Yasemin; Cosar, Murat

    2015-01-01

    Objective The main causes of spinal cord ischemia are a variety of vascular pathologies causing acute arterial occlusions. We investigated neuroprotective effects of kefir on spinal cord ischemia injury in rats. Methods Rats were divided into three groups : 1) sham operated control rats; 2) spinal cord ischemia group fed on a standard diet without kefir pretreatment; and 3) spinal cord ischemia group fed on a standard diet plus kefir. Spinal cord ischemia was performed by the infrarenal aorta cross-clamping model. The spinal cord was removed after the procedure. The biochemical and histopathological changes were observed within the samples. Functional assessment was performed for neurological deficit scores. Results The kefir group was compared with the ischemia group, a significant decrease in malondialdehyde levels was observed (pkefir group were significantly higher than ischemia group (pkefir group is compared with ischemia group, there was a significant decrease in numbers of dead and degenerated neurons (pkefir group compared with ischemia group (pkefir group were significantly higher than ischemia group at 24 h (pkefir pretreatment in spinal cord ischemia/reperfusion reduced oxidative stress and neuronal degeneration as a neuroprotective agent. Ultrastructural studies are required in order for kefir to be developed as a promising therapeutic agent to be utilized for human spinal cord ischemia in the future. PMID:26113960

  5. The Neuroprotective Effect of Kefir on Spinal Cord Ischemia/Reperfusion Injury in Rats.

    Science.gov (United States)

    Guven, Mustafa; Akman, Tarik; Yener, Ali Umit; Sehitoglu, Muserref Hilal; Yuksel, Yasemin; Cosar, Murat

    2015-05-01

    The main causes of spinal cord ischemia are a variety of vascular pathologies causing acute arterial occlusions. We investigated neuroprotective effects of kefir on spinal cord ischemia injury in rats. Rats were divided into three groups : 1) sham operated control rats; 2) spinal cord ischemia group fed on a standard diet without kefir pretreatment; and 3) spinal cord ischemia group fed on a standard diet plus kefir. Spinal cord ischemia was performed by the infrarenal aorta cross-clamping model. The spinal cord was removed after the procedure. The biochemical and histopathological changes were observed within the samples. Functional assessment was performed for neurological deficit scores. The kefir group was compared with the ischemia group, a significant decrease in malondialdehyde levels was observed (pkefir group were significantly higher than ischemia group (pkefir group is compared with ischemia group, there was a significant decrease in numbers of dead and degenerated neurons (pkefir group compared with ischemia group (pkefir group were significantly higher than ischemia group at 24 h (pkefir pretreatment in spinal cord ischemia/reperfusion reduced oxidative stress and neuronal degeneration as a neuroprotective agent. Ultrastructural studies are required in order for kefir to be developed as a promising therapeutic agent to be utilized for human spinal cord ischemia in the future.

  6. An odor interaction model of binary odorant mixtures by a partial differential equation method.

    Science.gov (United States)

    Yan, Luchun; Liu, Jiemin; Wang, Guihua; Wu, Chuandong

    2014-07-09

    A novel odor interaction model was proposed for binary mixtures of benzene and substituted benzenes by a partial differential equation (PDE) method. Based on the measurement method (tangent-intercept method) of partial molar volume, original parameters of corresponding formulas were reasonably displaced by perceptual measures. By these substitutions, it was possible to relate a mixture's odor intensity to the individual odorant's relative odor activity value (OAV). Several binary mixtures of benzene and substituted benzenes were respectively tested to establish the PDE models. The obtained results showed that the PDE model provided an easily interpretable method relating individual components to their joint odor intensity. Besides, both predictive performance and feasibility of the PDE model were proved well through a series of odor intensity matching tests. If combining the PDE model with portable gas detectors or on-line monitoring systems, olfactory evaluation of odor intensity will be achieved by instruments instead of odor assessors. Many disadvantages (e.g., expense on a fixed number of odor assessors) also will be successfully avoided. Thus, the PDE model is predicted to be helpful to the monitoring and management of odor pollutions.

  7. An Odor Interaction Model of Binary Odorant Mixtures by a Partial Differential Equation Method

    Directory of Open Access Journals (Sweden)

    Luchun Yan

    2014-07-01

    Full Text Available A novel odor interaction model was proposed for binary mixtures of benzene and substituted benzenes by a partial differential equation (PDE method. Based on the measurement method (tangent-intercept method of partial molar volume, original parameters of corresponding formulas were reasonably displaced by perceptual measures. By these substitutions, it was possible to relate a mixture’s odor intensity to the individual odorant’s relative odor activity value (OAV. Several binary mixtures of benzene and substituted benzenes were respectively tested to establish the PDE models. The obtained results showed that the PDE model provided an easily interpretable method relating individual components to their joint odor intensity. Besides, both predictive performance and feasibility of the PDE model were proved well through a series of odor intensity matching tests. If combining the PDE model with portable gas detectors or on-line monitoring systems, olfactory evaluation of odor intensity will be achieved by instruments instead of odor assessors. Many disadvantages (e.g., expense on a fixed number of odor assessors also will be successfully avoided. Thus, the PDE model is predicted to be helpful to the monitoring and management of odor pollutions.

  8. CB2 cannabinoid receptors modulate HIF-1α and TIM-3 expression in a hypoxia-ischemia mouse model.

    Science.gov (United States)

    Kossatz, Elk; Maldonado, Rafael; Robledo, Patricia

    2016-12-01

    The role of CB2 cannabinoid receptors (CB 2 R) in global brain lesions induced by hypoxia-ischemia (HI) insult is still unresolved. The aim of this study was to evaluate the involvement of CB 2 R in the behavioural and biochemical underpinnings related to brain damage induced by HI in adult mice, and the mechanisms involved. CB 2 R knockout (KO) mice and wild-type littermates (WT) underwent permanent ligation of the left common carotid artery and hypoxia. Behavioural measurements in the rotarod, beam walking, object recognition, open field, and Irwin tests were carried out 24h, 72h and 7 days. In KO mice, more extensive brain injury was observed. Behavioural deficits in the Irwin test were observed in both genotypes; while WT mice showed progressive recovery by day 7, KO mice did not. Only KO mice showed alterations in motor learning, coordination and balance, and did not recover over time. A higher expression of microglia and astrocytes was observed in several brain areas of lesioned WT and KO mice. The possible alteration of the inflammatory-related factors HIF-1α and TIM-3 was evaluated in these animals. In both genotypes, HIF-1α and TIM-3 expression was observed in lesioned areas associated with activated microglia. However, the expression levels of these proteins were exacerbated in KO mice in several lesioned and non-lesioned brain structures. Our results indicate that CB 2 R may have a crucial neuroprotective role following HI insult through the modulation of the inflammatory-related HIF-1α/TIM-3 signalling pathway in microglia. Copyright © 2016 Elsevier B.V. and ECNP. All rights reserved.

  9. Quantitative phosphoproteomics using acetone-based peptide labeling: Method evaluation and application to a cardiac ischemia/reperfusion model

    Science.gov (United States)

    Wijeratne, Aruna B.; Manning, Janet R.; Schultz, Jo El J.; Greis, Kenneth D.

    2013-01-01

    Mass spectrometry (MS) techniques to globally profile protein phosphorylation in cellular systems that are relevant to physiological or pathological changes have been of significant interest in biological research. In this report, an MS-based strategy utilizing an inexpensive acetone-based peptide labeling technique known as reductive alkylation by acetone (RABA) for quantitative phosphoproteomics was explored to evaluate its capacity. Since the chemistry for RABA-labeling for phosphorylation profiling had not been previously reported, it was first validated using a standard phosphoprotein and identical phosphoproteomes from cardiac tissue extracts. A workflow was then utilized to compare cardiac tissue phosphoproteomes from mouse hearts not expressing FGF2 vs. hearts expressing low molecular weight fibroblast growth factor-2 (LMW FGF2) to relate low molecular weight fibroblast growth factor-2 (LMW FGF2) mediated cardioprotective phenomena induced by ischemia/reperfusion (I/R) injury of hearts, with downstream phosphorylation changes in LMW FGF2 signaling cascades. Statistically significant phosphorylation changes were identified at 14 different sites on 10 distinct proteins including some with mechanisms already established for LMW FGF2-mediated cardioprotective signaling (e.g. connexin-43), some with new details linking LMW FGF2 to the cardioprotective mechanisms (e.g. cardiac myosin binding protein C or cMyBPC), and also several new downstream effectors not previously recognized for cardio-protective signaling by LMW FGF2. Additionally, one of the phosphopeptides, cMyBPC/pSer-282, identified was further verified with site-specific quantification using an SRM (selected reaction monitoring)-based approach that also relies on isotope labeling of a synthetic phosphopeptide with deuterated acetone as an internal standard. Overall, this study confirms that the inexpensive acetone-based peptide labeling can be used in both exploratory and targeted quantification

  10. Radial extracorporeal shock wave therapy improves cerebral blood flow and neurological function in a rat model of cerebral ischemia.

    Science.gov (United States)

    Kang, Nan; Zhang, Jing; Yu, Xiaotong; Ma, Yuewen

    2017-01-01

    We performed middle cerebral artery occlusion (MCAO) in rats to investigate the effect and some of the underlying mechanisms of radial extracorporeal shock wave therapy (rESWT) in cerebral ischemia rats. We measured neurological function and cerebral blood flow (CBF) using a full-field laser perfusion imager and brain infarct volume on days 3, 12, and 30. Immunofluorescence, western blot, and real-time polymerase chain reaction (PCR) techniques were used to detect the expression of vascular endothelial growth factor (VEGF), neuron-specific enolase (NSE), nestin, Wnt3a, and β-catenin in the ischemic hemisphere. The dose of rESWT used on the head revealed remarkable advantages over sham rESWT, as demonstrated by improved neurological function scores, increased CBF, and reduced brain infarct volume. Furthermore, applying rESWT to the head and limbs enhanced short-term neurological function. Our results confirmed that rESWT can induce VEGF expression over an extended period with a profound effect, which may be the primary reason for CBF recovery. High NSE and nestin expression levels suggest that rESWT enhanced the number of neurons and neural stem cells (NSCs). Wnt3a and β-catenin expression were up-regulated in the ischemic hemisphere, indicating that rESWT promoted NSC proliferation and differentiation via the Wnt/β-catenin pathway. Overall, our findings suggest that an appropriate rESWT dose delivered to the head of rats helps restore neurological function and CBF, and additional application of rESWT to the limbs is more effective than treating the head alone.

  11. Robust-BD Estimation and Inference for General Partially Linear Models

    Directory of Open Access Journals (Sweden)

    Chunming Zhang

    2017-11-01

    Full Text Available The classical quadratic loss for the partially linear model (PLM and the likelihood function for the generalized PLM are not resistant to outliers. This inspires us to propose a class of “robust-Bregman divergence (BD” estimators of both the parametric and nonparametric components in the general partially linear model (GPLM, which allows the distribution of the response variable to be partially specified, without being fully known. Using the local-polynomial function estimation method, we propose a computationally-efficient procedure for obtaining “robust-BD” estimators and establish the consistency and asymptotic normality of the “robust-BD” estimator of the parametric component β o . For inference procedures of β o in the GPLM, we show that the Wald-type test statistic W n constructed from the “robust-BD” estimators is asymptotically distribution free under the null, whereas the likelihood ratio-type test statistic Λ n is not. This provides an insight into the distinction from the asymptotic equivalence (Fan and Huang 2005 between W n and Λ n in the PLM constructed from profile least-squares estimators using the non-robust quadratic loss. Numerical examples illustrate the computational effectiveness of the proposed “robust-BD” estimators and robust Wald-type test in the appearance of outlying observations.

  12. Consequences of the partial restoration of chiral symmetry in an AdS/QCD model

    International Nuclear Information System (INIS)

    Kim, Youngman; Lee, Hyun Kyu

    2008-01-01

    Chiral symmetry is an essential concept in understanding QCD at low energy. We treat the chiral condensate, which measures the spontaneous breaking of chiral symmetry, as a free parameter to investigate the effect of partially restored chiral symmetry on the physical quantities in the framework of an AdS/QCD model. We observe an interesting scaling behavior among the nucleon mass, pion decay constant, and chiral condensate. We propose a phenomenological way to introduce the temperature dependence of a physical quantity in the AdS/QCD model with the thermal AdS metric.

  13. The partial duration series method in regional index-flood modeling

    DEFF Research Database (Denmark)

    Madsen, Henrik; Rosbjerg, Dan

    1997-01-01

    A regional index-flood method based on the partial duration series model is introduced. The model comprises the assumptions of a Poisson-distributed number of threshold exceedances and generalized Pareto (GP) distributed peak magnitudes. The regional T-year event estimator is based on a regional...... estimator is superior to the at-site estimator even in extremely heterogenous regions, the performance of the regional estimator being relatively better in regions with a negative shape parameter. When the record length increases, the relative performance of the regional estimator decreases, but it is still...

  14. Generalized least squares and empirical Bayes estimation in regional partial duration series index-flood modeling

    DEFF Research Database (Denmark)

    Madsen, Henrik; Rosbjerg, Dan

    1997-01-01

    parameters is inferred from regional data using generalized least squares (GLS) regression. Two different Bayesian T-year event estimators are introduced: a linear estimator that requires only some moments of the prior distributions to be specified and a parametric estimator that is based on specified......A regional estimation procedure that combines the index-flood concept with an empirical Bayes method for inferring regional information is introduced. The model is based on the partial duration series approach with generalized Pareto (GP) distributed exceedances. The prior information of the model...

  15. Exotic muon-to-positron conversion in nuclei: partial transition sum evaluation by using shell model

    International Nuclear Information System (INIS)

    Divari, P.C.; Vergados, J.D.; Kosmas, T.S.; Skouras, L.D.

    2001-01-01

    A comprehensive study of the exotic (μ - ,e + ) conversion in 27 Al, 27 Al(μ - ,e + ) 27 Na is presented. The relevant operators are deduced assuming one-pion and two-pion modes in the framework of intermediate neutrino mixing models, paying special attention to the light neutrino case. The total rate is calculated by summing over partial transition strengths for all kinematically accessible final states derived with s-d shell model calculations employing the well-known Wildenthal realistic interaction

  16. In vivo study of myocardial elastography under graded ischemia conditions

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Wei-Ning; Provost, Jean; Konofagou, Elisa E [Department of Biomedical Engineering, Columbia University, New York, NY (United States); Fujikura, Kana [Department of Radiology, Columbia University, New York, NY (United States); Wang Jie, E-mail: ek2191@columbia.edu [Department of Medicine, Columbia University, New York, NY (United States)

    2011-02-21

    The capability of currently available echocardiography-based strain estimation techniques to fully map myocardial abnormality at early stages of myocardial ischemia is yet to be investigated. In this study, myocardial elastography (ME), a radio-frequency (RF)-based strain imaging technique that maps the full 2D transmural angle-independent strain tensor in standard echocardiographic views at both high spatial and temporal resolution is presented. The objectives were to (1) evaluate the performance of ME on mapping the onset, extent and progression of myocardial ischemia at graded coronary constriction levels (from partial to complete coronary flow reduction), and (2) validate the accuracy of the strain estimates against sonomicrometry (SM) measurements. A non-survival canine ischemic model (n = 5) was performed by gradually constricting the left anterior descending (LAD) coronary blood flow from 0% (baseline blood flow) to 100% (zero blood flow) at 20% increments. An open-architecture ultrasound system was used to acquire RF echocardiograms in a standard full short-axis view at the frame rate of 211 fps, at least twice higher than what is typically used in conventional echocardiographic systems, using a previously developed, fully automated composite technique. Myocardial deformation was estimated by ME and validated against sonomicrometry. ME estimates and maps transmural (1) 2D displacements using RF cross-correlation and recorrelation; and (2) 2D polar (radial and circumferential) strains, derived from 2D (i.e. both lateral and axial) displacement components, at high accuracy. Full-view strain images were shown and found to reliably depict decreased myocardial function in the region at risk at increased levels of coronary flow reduction. The ME radial strain was deemed to be a more sensitive, quantitative, regional measure of myocardial ischemia as a result of coronary flow reduction when compared to the conventional wall motion score index and ejection fraction

  17. Partial molar volume of proteins studied by the three-dimensional reference interaction site model theory.

    Science.gov (United States)

    Imai, Takashi; Kovalenko, Andriy; Hirata, Fumio

    2005-04-14

    The three-dimensional reference interaction site model (3D-RISM) theory is applied to the analysis of hydration effects on the partial molar volume of proteins. For the native structure of some proteins, the partial molar volume is decomposed into geometric and hydration contributions using the 3D-RISM theory combined with the geometric volume calculation. The hydration contributions are correlated with the surface properties of the protein. The thermal volume, which is the volume of voids around the protein induced by the thermal fluctuation of water molecules, is directly proportional to the accessible surface area of the protein. The interaction volume, which is the contribution of electrostatic interactions between the protein and water molecules, is apparently governed by the charged atomic groups on the protein surface. The polar atomic groups do not make any contribution to the interaction volume. The volume differences between low- and high-pressure structures of lysozyme are also analyzed by the present method.

  18. Partial Overhaul and Initial Parallel Optimization of KINETICS, a Coupled Dynamics and Chemistry Atmosphere Model

    Science.gov (United States)

    Nguyen, Howard; Willacy, Karen; Allen, Mark

    2012-01-01

    KINETICS is a coupled dynamics and chemistry atmosphere model that is data intensive and computationally demanding. The potential performance gain from using a supercomputer motivates the adaptation from a serial version to a parallelized one. Although the initial parallelization had been done, bottlenecks caused by an abundance of communication calls between processors led to an unfavorable drop in performance. Before starting on the parallel optimization process, a partial overhaul was required because a large emphasis was placed on streamlining the code for user convenience and revising the program to accommodate the new supercomputers at Caltech and JPL. After the first round of optimizations, the partial runtime was reduced by a factor of 23; however, performance gains are dependent on the size of the data, the number of processors requested, and the computer used.

  19. Sildenafil Protects against Myocardial Ischemia-Reperfusion Injury Following Cardiac Arrest in a Porcine Model: Possible Role of the Renin-Angiotensin System

    Science.gov (United States)

    Wang, Guoxing; Zhang, Qian; Yuan, Wei; Wu, Junyuan; Li, Chunsheng

    2015-01-01

    Sildenafil, a phosphodiesterase-5 inhibitor sold as Viagra, is a cardioprotector against myocardial ischemia/reperfusion (I/R) injury. Our study explored whether sildenafil protects against I/R-induced damage in a porcine cardiac arrest and resuscitation (CAR) model via modulating the renin-angiotensin system. Male pigs were randomly divided to three groups: Sham group, Saline group, and sildenafil (0.5 mg/kg) group. Thirty min after drug infusion, ventricular fibrillation (8 min) and cardiopulmonary resuscitation (up to 30 min) was conducted in these animals. We found that sildenafil ameliorated the reduced cardiac function and improved the 24-h survival rate in this model. Sildenafil partly attenuated the increases of plasma angiotensin II (Ang II) and Ang (1–7) levels after CAR. Sildenafil also decreased apoptosis and Ang II expression in myocardium. The increases of expression of angiotensin-converting-enzyme (ACE), ACE2, Ang II type 1 receptor (AT1R), and the Ang (1–7) receptor Mas in myocardial tissue were enhanced after CAR. Sildenafil suppressed AT1R up-regulation, but had no effect on ACE, ACE2, and Mas expression. Sildenafilfurther boosted the upregulation of endothelial nitric oxide synthase (eNOS), cyclic guanosine monophosphate (cGMP) and inducible nitric oxide synthase(iNOS). Collectively, our results suggest that cardioprotection of sildenafil in CAR model is accompanied by an inhibition of Ang II-AT1R axis activation. PMID:26569234

  20. Sildenafil Protects against Myocardial Ischemia-Reperfusion Injury Following Cardiac Arrest in a Porcine Model: Possible Role of the Renin-Angiotensin System

    Directory of Open Access Journals (Sweden)

    Guoxing Wang

    2015-11-01

    Full Text Available Sildenafil, a phosphodiesterase-5 inhibitor sold as Viagra, is a cardioprotector against myocardial ischemia/reperfusion (I/R injury. Our study explored whether sildenafil protects against I/R-induced damage in a porcine cardiac arrest and resuscitation (CAR model via modulating the renin-angiotensin system. Male pigs were randomly divided to three groups: Sham group, Saline group, and sildenafil (0.5 mg/kg group. Thirty min after drug infusion, ventricular fibrillation (8 min and cardiopulmonary resuscitation (up to 30 min was conducted in these animals. We found that sildenafil ameliorated the reduced cardiac function and improved the 24-h survival rate in this model. Sildenafil partly attenuated the increases of plasma angiotensin II (Ang II and Ang (1–7 levels after CAR. Sildenafil also decreased apoptosis and Ang II expression in myocardium. The increases of expression of angiotensin-converting-enzyme (ACE, ACE2, Ang II type 1 receptor (AT1R, and the Ang (1–7 receptor Mas in myocardial tissue were enhanced after CAR. Sildenafil suppressed AT1R up-regulation, but had no effect on ACE, ACE2, and Mas expression. Sildenafilfurther boosted the upregulation of endothelial nitric oxide synthase (eNOS, cyclic guanosine monophosphate (cGMP and inducible nitric oxide synthase(iNOS. Collectively, our results suggest that cardioprotection of sildenafil in CAR model is accompanied by an inhibition of Ang II-AT1R axis activation.

  1. Modified multiblock partial least squares path modeling algorithm with backpropagation neural networks approach

    Science.gov (United States)

    Yuniarto, Budi; Kurniawan, Robert

    2017-03-01

    PLS Path Modeling (PLS-PM) is different from covariance based SEM, where PLS-PM use an approach based on variance or component, therefore, PLS-PM is also known as a component based SEM. Multiblock Partial Least Squares (MBPLS) is a method in PLS regression which can be used in PLS Path Modeling which known as Multiblock PLS Path Modeling (MBPLS-PM). This method uses an iterative procedure in its algorithm. This research aims to modify MBPLS-PM with Back Propagation Neural Network approach. The result is MBPLS-PM algorithm can be modified using the Back Propagation Neural Network approach to replace the iterative process in backward and forward step to get the matrix t and the matrix u in the algorithm. By modifying the MBPLS-PM algorithm using Back Propagation Neural Network approach, the model parameters obtained are relatively not significantly different compared to model parameters obtained by original MBPLS-PM algorithm.

  2. A Partially-Stirred Batch Reactor Model for Under-Ventilated Fire Dynamics

    Science.gov (United States)

    McDermott, Randall; Weinschenk, Craig

    2013-11-01

    A simple discrete quadrature method is developed for closure of the mean chemical source term in large-eddy simulations (LES) and implemented in the publicly available fire model, Fire Dynamics Simulator (FDS). The method is cast as a partially-stirred batch reactor model for each computational cell. The model has three distinct components: (1) a subgrid mixing environment, (2) a mixing model, and (3) a set of chemical rate laws. The subgrid probability density function (PDF) is described by a linear combination of Dirac delta functions with quadrature weights set to satisfy simple integral constraints for the computational cell. It is shown that under certain limiting assumptions, the present method reduces to the eddy dissipation concept (EDC). The model is used to predict carbon monoxide concentrations in direct numerical simulation (DNS) of a methane slot burner and in LES of an under-ventilated compartment fire.

  3. [The relationship between ischemic preconditioning-induced infarction size limitation and duration of test myocardial ischemia].

    Science.gov (United States)

    Blokhin, I O; Galagudza, M M; Vlasov, T D; Nifontov, E M; Petrishchev, N N

    2008-07-01

    Traditionally infarction size reduction by ischemic preconditioning is estimated in duration of test ischemia. This approach limits the understanding of real antiischemic efficacy of ischemic preconditioning. Present study was performed in the in vivo rat model of regional myocardial ischemia-reperfusion and showed that protective effect afforded by ischemic preconditioning progressively decreased with prolongation of test ischemia. There were no statistically significant differences in infarction size between control and preconditioned animals when the duration of test ischemia was increased up to 1 hour. Preconditioning ensured maximal infarction-limiting effect in duration of test ischemia varying from 20 to 40 minutes.

  4. Effect of nano-silver hydrogel coating film on deep partial thickness scald model of rabbit.

    Science.gov (United States)

    Xi, Peng; Li, Yan; Ge, Xiaojin; Liu, Dandan; Miao, Mingsan

    2018-05-01

    Observing the effect of nano-silver hydrogel coating film on deep partial thickness scald model of rabbit. We prepared boiling water scalded rabbits with deep II degree scald models and applied high, medium and low doses of nano-silver hydrogel coating film for different time and area. Then we compared the difference of burned paper weight before administration and after administration model burns, burn local skin irritation points infection, skin crusting and scabs from the time, and the impact of local skin tissue morphology. Rabbits deep II degree burn model successful modeling; on day 12, 18, high, medium and low doses of nano-silver hydrogel coating film significantly reduced skin irritation of rabbits infected with the integral value ( P  film group significantly decreased skin irritation, infection integral value ( P  film significantly reduced film rabbits' scalded skin crusting time ( P  film on the deep partial thickness burns has a significant therapeutic effect; external use has a significant role in wound healing.

  5. Whole object surface area and volume of partial-view 3D models

    International Nuclear Information System (INIS)

    Mulukutla, Gopal K; Proussevitch, Alexander A; Genareau, Kimberly D; Durant, Adam J

    2017-01-01

    Micro-scale 3D models, important components of many studies in science and engineering, are often used to determine morphological characteristics such as shape, surface area and volume. The application of techniques such as stereoscopic scanning electron microscopy on whole objects often results in ‘partial-view’ models with a portion of object not within the field of view thus not captured in the 3D model. The nature and extent of the surface not captured is dependent on the complex interaction of imaging system attributes (e.g. working distance, viewing angle) with object size, shape and morphology. As a result, any simplistic assumptions in estimating whole object surface area or volume can lead to significant errors. In this study, we report on a novel technique to estimate the physical fraction of an object captured in a partial-view 3D model of an otherwise whole object. This allows a more accurate estimate of surface area and volume. Using 3D models, we demonstrate the robustness of this method and the accuracy of surface area and volume estimates relative to true values. (paper)

  6. Life time test of a partial model of HTGR helium-helium heat exchanger

    International Nuclear Information System (INIS)

    Kitagawa, Masaki; Hattori, Hiroshi; Ohtomo, Akira; Teramae, Tetsuo; Hamanaka, Junichi; Itoh, Mitsuyoshi; Urabe, Shigemi

    1984-01-01

    Authors had proposed a design guide for the HTGR components and applied it to the design and construction of the 1.5 Mwt helium heat exchanger test loop for the nuclear steel making under the financial support of the Japanese Ministry of International Trade and Industry. In order to assure that the design method covers all the conceivable failure mode and has enough safety margin, a series of life time tests of partial model may be needed. For this project, three types of model tests were performed. A life time test of a partial model of the center manifold pipe and eight heat exchanger tubes were described in this report. A damage criterion with a set of material constants and a simplified method for stress-strain analysis for stub tube under three dimensional load were newly developed and used to predict the lives of each tube. The predicted lives were compared with the experimental lives and good agreement was found between the two. The life time test model was evaluated according to the proposed design guide and it was found that the guide has a safety factor of approximately 200 in life for this particular model. (author)

  7. A new nonlinear turbulence model based on Partially-Averaged Navier-Stokes Equations

    International Nuclear Information System (INIS)

    Liu, J T; Wu, Y L; Cai, C; Liu, S H; Wang, L Q

    2013-01-01

    Partially-averaged Navier-Stokes (PANS) Model was recognized as a Reynolds-averaged Navier-Stokes (RANS) to direct numerical simulation (DNS) bridging method. PANS model was purported for any filter width-from RANS to DNS. PANS method also shared some similarities with the currently popular URANS (unsteady RANS) method. In this paper, a new PANS model was proposed, which was based on RNG k-ε turbulence model. The Standard and RNG k-ε turbulence model were both isotropic models, as well as PANS models. The sheer stress in those PANS models was solved by linear equation. The linear hypothesis was not accurate in the simulation of complex flow, such as stall phenomenon. The sheer stress here was solved by nonlinear method proposed by Ehrhard. Then, the nonlinear PANS model was set up. The pressure coefficient of the suction side of the NACA0015 hydrofoil was predicted. The result of pressure coefficient agrees well with experimental result, which proves that the nonlinear PANS model can capture the high pressure gradient flow. A low specific centrifugal pump was used to verify the capacity of the nonlinear PANS model. The comparison between the simulation results of the centrifugal pump and Particle Image Velocimetry (PIV) results proves that the nonlinear PANS model can be used in the prediction of complex flow field

  8. Effect of different component ratio of Astragalus total saponins and Verbena total glycosides on the cerebral infarction area and serum biochemical indicators in the focal cerebral ischemia-reperfusion rat model

    Directory of Open Access Journals (Sweden)

    Erping Xu

    2017-05-01

    Full Text Available Our purpose is to study the effect of different component ratio of Astragalus Total Saponins (ATS and Verbena Total Glycosides (VTG on the cerebral infarction area and the serum biochemical indicators in the focal cerebral ischemia-reperfusion rat model. Compared with the model group, different component ratio of ATS and VTG could significantly improve the neurological deficit scores to the focal cerebral ischemia-reperfusion rat model, and the group of 7:3, 6:4, 5:5 got the best results; it could reduce the mortality of rat model to a certain extent, and the group of 5:5 group got the best results; it can significantly reduce the cerebral infarction area, and the group of 7:3, 5:5, 4:6 got the best results; it could significantly reduce the content of TNF-α, and the group of 8:2, 6:4 got the best results; it could significantly reduce the content of NO, and the group of 7:3, 5:5 got the best results; it could significantly increase the content of SOD, and the group of 6:4, 5:5 got the best results. This indicates that different component ratio of ATS and VTG may protect the damage of focal cerebral ischemia-reperfusion rat model to a certain extent, which are compared using the comprehensive weight method and the ratio of 5:5 was proved to be the optimal active ratio.

  9. Numerical modeling of spray combustion in DI diesel engine using partially stirred reactor (PaSR) model

    International Nuclear Information System (INIS)

    Khaleghi, H.; Hosseini, S.M.

    2003-01-01

    In recent years special attention has been paid to the topic of diesel engine combustion. Various combustion models are used in CFD codes. In this paper Partially Stirred Reactor (PaSR) model, one of the newest turbulent combustion models, is introduced. This model has been employed in conjunction with the non-iterative PISO algorithm to calculate spray combustion in an axi-symmetric, direct injection diesel engine. Qualitative consideration of the results shows very good agreement with physical expectations and other numerical and experimental results. (author)

  10. CFD modeling of combustion processes using KIVA3V Code with partially stirred reactor model for turbulence-combustion interactions

    International Nuclear Information System (INIS)

    Jarnicki, R.; Sobiesiak, A.

    2002-01-01

    In order to solve the averaged conservation equations for turbulent reacting flow one is faced with a task of specifying the averaged chemical reaction rate. This is due to turbulence influence on the mean reaction rates that appear in the species concentration Reynolds-averaged equation. In order to investigate the Partially Stirred Reactor (PaSR) combustion model capabilities, a CFD modeling using KIVA3V Code with the PaSR model of two very different combustion processes, was performed. Experimental results were compared with modeling

  11. Clinical significance of changes of serum IL-6 and TNF-α levels in rat models of hypoxic-ischemia brain injury

    International Nuclear Information System (INIS)

    Niu Tingxian; Shi Zhiyong; Luo Jianjun

    2009-01-01

    Objective: To explore the clinical significance of changes of serum interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) levels in rat models of hypoxic-ischemia (HI) brain injury. Methods: Seventy five rat HI brain injury nodels were prepared with bilateral occlusion of common carotid artery for 24rs followed 2hrs later by hypoxia (breathing 8% oxygen) for 2hrs. One fifth of the animals were sacrificed at 4h, 8h, 12h, 24h and 48h later respectively, the serum and brain homogenate concentrations of IL-6 and TNF-α were determined with RIA and brain tissues were pathologically examined. Results: The concentrations of IL-6 and TNF-α were dynamically changed within 48h in serum and brain homogenate. Peak values occurred at 24h with serum and at 12h with brain homogenate. Meanwhile, levels of both cytokines were significantly higher in the models than those in controls (P<0.01 or P<0.05). Conclusion: The concentrations of IL-6 and TNF-α were dynamically(sham operation only, 15 animals) changed and might be regarded as the clinical markers of degree of HI brain injury. (authors)

  12. Spinal cord ischemia following thoracotomy without epidural anesthesia.

    Science.gov (United States)

    Raz, Aeyal; Avramovich, Aharon; Saraf-Lavi, Efrat; Saute, Milton; Eidelman, Leonid A

    2006-06-01

    Paraplegia is an uncommon yet devastating complication following thoracotomy, usually caused by compression or ischemia of the spinal cord. Ischemia without compression may be a result of global ischemia, vascular injury and other causes. Epidural anesthesia has been implicated as a major cause. This report highlights the fact that perioperative cord ischemia and paraplegia may be unrelated to epidural intervention. A 71-yr-old woman was admitted for a left upper lobectomy for resection of a non-small cell carcinoma of the lung. The patient refused epidural catheter placement and underwent a left T5-6 thoracotomy under general anesthesia. During surgery, she was hemodynamically stable and good oxygen saturation was maintained. Several hours following surgery the patient complained of loss of sensation in her legs. Neurological examination disclosed a complete motor and sensory block at the T5-6 level. Magnetic resonance imaging (MRI) revealed spinal cord ischemia. The patient received iv steroid treatment, but remained paraplegic. Five months following the surgery there was only partial improvement in her motor symptoms. A follow-up MRI study was consistent with a diagnosis of spinal cord ischemia. In this case of paraplegia following thoracic surgery for lung resection, epidural anesthesia/analgesia was not used. The MRI demonstrated evidence of spinal cord ischemia, and no evidence of cord compression. This case highlights that etiologies other than epidural intervention, such as injury to the spinal segmental arteries during thoracotomy, should be considered as potential causes of cord ischemia and resultant paraplegia in this surgical population.

  13. Comparison of using different bridge prosthetic designs for partial defect restoration through mathematical modeling.

    Science.gov (United States)

    Styranivska, Oksana; Kliuchkovska, Nataliia; Mykyyevych, Nataliya

    2017-01-01

    To analyze the stress-strain states of bone and abutment teeth during the use of different prosthetic designs of fixed partial dentures with the use of relevant mathematical modeling principles. The use of Comsol Multiphysics 3.5 (Comsol AB, Sweden) software during the mathematical modeling of stress-strain states provided numerical data for analytical interpretation in three different clinical scenarios with fixed dentures and different abutment teeth and demountable prosthetic denture with the saddle-shaped intermediate part. Microsoft Excel Software (Microsoft Office 2017) helped to evaluate absolute mistakes of stress and strain parameters of each abutment tooth during three modeled scenarios and normal condition and to summarize data into the forms of tables. In comparison with the fixed prosthetic denture supported by the canine, first premolar, and third molar, stresses at the same abutment teeth with the use of demountable denture with the saddle-shaped intermediate part decreased: at the mesial abutment tooth by 2.8 times, at distal crown by 6.1 times, and at the intermediate part by 11.1 times, respectively, the deformation level decreased by 3.1, 1.9, and 1.4 times at each area. The methods of mathematical modeling proved that complications during the use of fixed partial dentures based on the overload effect of the abutment teeth and caused by the deformation process inside the intermediate section of prosthetic construction.

  14. Partial least squares path modeling basic concepts, methodological issues and applications

    CERN Document Server

    Noonan, Richard

    2017-01-01

    This edited book presents the recent developments in partial least squares-path modeling (PLS-PM) and provides a comprehensive overview of the current state of the most advanced research related to PLS-PM. The first section of this book emphasizes the basic concepts and extensions of the PLS-PM method. The second section discusses the methodological issues that are the focus of the recent development of the PLS-PM method. The third part discusses the real world application of the PLS-PM method in various disciplines. The contributions from expert authors in the field of PLS focus on topics such as the factor-based PLS-PM, the perfect match between a model and a mode, quantile composite-based path modeling (QC-PM), ordinal consistent partial least squares (OrdPLSc), non-symmetrical composite-based path modeling (NSCPM), modern view for mediation analysis in PLS-PM, a multi-method approach for identifying and treating unobserved heterogeneity, multigroup analysis (PLS-MGA), the assessment of the common method b...

  15. Rasch-Master's Partial Credit Model in the assessment of children's creativity in drawings.

    Science.gov (United States)

    Nakano, Tatiana de Cássia; Primi, Ricardo

    2014-01-01

    The purpose of the present study was to use the Partial Credit Model to study the factors of the Test of Creativity in Children and identify which characteristics of the creative person would be more effective to differentiate subjects according to their ability level. A sample of 1426 students from first to eighth grades answered the instrument. The Partial Credits model was used to estimate the ability of the subjects and item difficulties on a common scale for each of the four factors, indicating which items required a higher level of creativity to be scored and will differentiate the more creative individuals. The results demonstrated that the greater part of the characteristics showed good fit indices, with values between 0.80 and 1.30 both infit and outfit, indicating a response pattern consistent with the model. The characteristics of Unusual Perspective, Expression of Emotion and Originality have been identified as better predictors of creative performance because requires greater ability level (usually above two standard deviation). These results may be used in the future development of an instrument's reduced form or simplification of the current correction model.

  16. Different methods of hilar clamping during partial nephrectomy: Impact on renal function.

    Science.gov (United States)

    Lee, Jeong Woo; Kim, Hwanik; Choo, Minsoo; Park, Yong Hyun; Ku, Ja Hyeon; Kim, Hyeon Hoe; Kwak, Cheol

    2014-03-01

    To evaluate the impact of different hilar clamping methods on changes in renal function after partial nephrectomy. We analyzed the clinical data of 369 patients who underwent partial nephrectomy for a single renal tumor of size ≤4.0 cm and a normal contralateral kidney. Patients were separated into three groups depending on hilar clamping method: non-clamping, cold ischemia and warm ischemia. Estimated glomerular filtration rate was examined at preoperative, nadir and 1 year postoperatively. Percent change in estimated glomerular filtration rate was used as the parameter to assess the renal functional outcome. Percent change in nadir estimated glomerular filtration rate in the non-clamping group was significantly less compared with the cold ischemia and warm ischemia groups (P hilar clamping (both warm ischemia and cold ischemia) were significantly associated with percent change in nadir estimated glomerular filtration rate, but not in 1-year estimated glomerular filtration rate. Non-clamping partial nephrectomy results in a lower percent change in nadir estimated glomerular filtration rate, whereas it carries an estimated glomerular filtration rate change at 1 year that is similar to partial nephrectomy with cold ischemia and warm ischemia. Cold ischemia and warm ischemia provide a similar effect on renal function. Therefore, when hilar clamping is required, minimization of ischemia time is necessary. © 2013 The Japanese Urological Association.

  17. A simple method for identifying parameter correlations in partially observed linear dynamic models.

    Science.gov (United States)

    Li, Pu; Vu, Quoc Dong

    2015-12-14

    Parameter estimation represents one of the most significant challenges in systems biology. This is because biological models commonly contain a large number of parameters among which there may be functional interrelationships, thus leading to the problem of non-identifiability. Although identifiability analysis has been extensively studied by analytical as well as numerical approaches, systematic methods for remedying practically non-identifiable models have rarely been investigated. We propose a simple method for identifying pairwise correlations and higher order interrelationships of parameters in partially observed linear dynamic models. This is made by derivation of the output sensitivity matrix and analysis of the linear dependencies of its columns. Consequently, analytical relations between the identifiability of the model parameters and the initial conditions as well as the input functions can be achieved. In the case of structural non-identifiability, identifiable combinations can be obtained by solving the resulting homogenous linear equations. In the case of practical non-identifiability, experiment conditions (i.e. initial condition and constant control signals) can be provided which are necessary for remedying the non-identifiability and unique parameter estimation. It is noted that the approach does not consider noisy data. In this way, the practical non-identifiability issue, which is popular for linear biological models, can be remedied. Several linear compartment models including an insulin receptor dynamics model are taken to illustrate the application of the proposed approach. Both structural and practical identifiability of partially observed linear dynamic models can be clarified by the proposed method. The result of this method provides important information for experimental design to remedy the practical non-identifiability if applicable. The derivation of the method is straightforward and thus the algorithm can be easily implemented into a

  18. Multi-scale diffuse interface modeling of multi-component two-phase flow with partial miscibility

    KAUST Repository

    Kou, Jisheng; Sun, Shuyu

    2016-01-01

    In this paper, we introduce a diffuse interface model to simulate multi-component two-phase flow with partial miscibility based on a realistic equation of state (e.g. Peng-Robinson equation of state). Because of partial miscibility, thermodynamic

  19. Fixed point and anomaly mediation in partial {\\boldsymbol{N}}=2 supersymmetric standard models

    Science.gov (United States)

    Yin, Wen

    2018-01-01

    Motivated by the simple toroidal compactification of extra-dimensional SUSY theories, we investigate a partial N = 2 supersymmetric (SUSY) extension of the standard model which has an N = 2 SUSY sector and an N = 1 SUSY sector. We point out that below the scale of the partial breaking of N = 2 to N = 1, the ratio of Yukawa to gauge couplings embedded in the original N = 2 gauge interaction in the N = 2 sector becomes greater due to a fixed point. Since at the partial breaking scale the sfermion masses in the N = 2 sector are suppressed due to the N = 2 non-renormalization theorem, the anomaly mediation effect becomes important. If dominant, the anomaly-induced masses for the sfermions in the N = 2 sector are almost UV-insensitive due to the fixed point. Interestingly, these masses are always positive, i.e. there is no tachyonic slepton problem. From an example model, we show interesting phenomena differing from ordinary MSSM. In particular, the dark matter particle can be a sbino, i.e. the scalar component of the N = 2 vector multiplet of {{U}}{(1)}Y. To obtain the correct dark matter abundance, the mass of the sbino, as well as the MSSM sparticles in the N = 2 sector which have a typical mass pattern of anomaly mediation, is required to be small. Therefore, this scenario can be tested and confirmed in the LHC and may be further confirmed by the measurement of the N = 2 Yukawa couplings in future colliders. This model can explain dark matter, the muon g-2 anomaly, and gauge coupling unification, and relaxes some ordinary problems within the MSSM. It is also compatible with thermal leptogenesis.

  20. Autoregressive Model with Partial Forgetting within Rao-Blackwellized Particle Filter

    Czech Academy of Sciences Publication Activity Database

    Dedecius, Kamil; Hofman, Radek

    2012-01-01

    Roč. 41, č. 5 (2012), s. 582-589 ISSN 0361-0918 R&D Projects: GA MV VG20102013018; GA ČR GA102/08/0567 Grant - others:ČVUT(CZ) SGS 10/099/OHK3/1T/16 Institutional research plan: CEZ:AV0Z10750506 Keywords : Bayesian methods * Particle filters * Recursive estimation Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 0.295, year: 2012 http://library.utia.cas.cz/separaty/2012/AS/dedecius-autoregressive model with partial forgetting within rao-blackwellized particle filter.pdf

  1. Screening for a Chronic Disease: A Multiple Stage Duration Model with Partial Observability.

    Science.gov (United States)

    Mroz, Thomas A; Picone, Gabriel; Sloan, Frank; Yashkin, Arseniy P

    2016-08-01

    We estimate a dynamic multi-stage duration model to investigate how early detection of diabetes can delay the onset of lower extremity complications and death. We allow for partial observability of the disease stage, unmeasured heterogeneity, and endogenous timing of diabetes screening. Timely diagnosis appears important. We evaluate the effectiveness of two potential policies to reduce the monetary costs of frequent screening in terms of lost longevity. Compared to the status quo, the more restrictive policy yields an implicit value for an additional year of life of about $50,000, while the less restrictive policy implies a value of about $120,000.

  2. A queueing model for error control of partial buffer sharing in ATM

    Directory of Open Access Journals (Sweden)

    Ahn Boo Yong

    1999-01-01

    Full Text Available We model the error control of the partial buffer sharing of ATM by a queueing system M 1 , M 2 / G / 1 / K + 1 with threshold and instantaneous Bernoulli feedback. We first derive the system equations and develop a recursive method to compute the loss probabilities at an arbitrary time epoch. We then build an approximation scheme to compute the mean waiting time of each class of cells. An algorithm is developed for finding the optimal threshold and queue capacity for a given quality of service.

  3. Pravastatin stimulates angiogenesis in a murine hindlimb ischemia model: a positron emission tomography imaging study with (64)Cu-NOTA-TRC105.

    Science.gov (United States)

    Orbay, Hakan; Hong, Hao; Koch, Jill M; Valdovinos, Hector F; Hacker, Timothy A; Theuer, Charles P; Barnhart, Todd E; Cai, Weibo

    2013-01-01

    In this study, (64)Cu-NOTA-TRC105 (TRC105 is an anti-CD105 monoclonal antibody that binds to both human and murine CD105) positron emission tomography (PET) was used to assess the response to pravastatin treatment in a murine model of peripheral artery disease (PAD). Hindlimb ischemia was induced by ligation of the right femoral arteries in BALB/c mice under anesthesia, and the left hindlimb served as an internal control. Mice in the treatment group were given intraperitoneal pravastatin daily until the end of the study, whereas the animals in the control group were injected with 0.9% sodium chloride solution. Laser Doppler imaging showed that blood flow in the ischemic hindlimb plummeted to ~20% of the normal level after surgery, and gradually recovered to near normal level on day 10 in the treatment group and on day 20 in the control group. Angiogenesis was non-invasively monitored and quantified with (64)Cu-NOTA-TRC105 PET on postoperative days 3, 10, 17, and 24. Tracer uptake at 48 h post-injection in the ischemic hindlimb in the treatment group was significantly higher than that of the control group on day 10 (20.5 ± 1.9 %ID/g vs 11.4 ± 1.5 %ID/g), suggesting increased CD105 expression and higher level of angiogenesis upon pravastatin treatment, and gradually decreased to background levels in both groups (4.9 ± 0.8 %ID/g vs 3.4 ± 1.9 %ID/g on day 24). The in vivo PET data correlated well with ex vivo biodistribution studies performed on day 24. Increased CD105 expression on days 3 and 10 following ischemia was further confirmed by immunofluorescence staining. Taken together, our results indicated that (64)Cu-NOTA-TRC105 PET is a suitable and non-invasive method to monitor the angiogenesis and therapeutic response in PAD, which can also be utilized for non-invasive evaluation of other pro-angiogenic/anti-angiogenic drugs in other cardiovascular diseases and cancer.

  4. Coenzyme Q10 partially restores pathological alterations in a macrophage model of Gaucher disease.

    Science.gov (United States)

    de la Mata, Mario; Cotán, David; Oropesa-Ávila, Manuel; Villanueva-Paz, Marina; de Lavera, Isabel; Álvarez-Córdoba, Mónica; Luzón-Hidalgo, Raquel; Suárez-Rivero, Juan M; Tiscornia, Gustavo; Sánchez-Alcázar, José A

    2017-02-06

    Gaucher disease (GD) is caused by mutations in the GBA1 gene which encodes lysosomal β-glucocerebrosidase (GCase). In GD, partial or complete loss of GCase activity causes the accumulation of the glycolipids glucosylceramide (GlcCer) and glucosylsphingosine in the lysosomes of macrophages. In this manuscript, we investigated the effects of glycolipids accumulation on lysosomal and mitochondrial function, inflammasome activation and efferocytosis capacity in a THP-1 macrophage model of Gaucher disease. In addition, the beneficial effects of coenzyme Q 10 (CoQ) supplementation on cellular alterations were evaluated. Chemically-induced Gaucher macrophages were developed by differentiateing THP-1 monocytes to macrophages by treatment with phorbol 12-myristate 13-acetate (PMA) and then inhibiting intracellular GCase with conduritol B-epoxide (CBE), a specific irreversible inhibitor of GCase activity, and supplementing the medium with exogenous GlcCer. This cell model accumulated up to 16-fold more GlcCer compared with control THP-1 cells. Chemically-induced Gaucher macrophages showed impaired autophagy flux associated with mitochondrial dysfunction and increased oxidative stress, inflammasome activation and impaired efferocytosis. All abnormalities were partially restored by supplementation with CoQ. These data suggest that targeting mitochondria function and oxidative stress by CoQ can ameliorate the pathological phenotype of Gaucher cells. Chemically-induced Gaucher macrophages provide cellular models that can be used to investigate disease pathogenesis and explore new therapeutics for GD.

  5. Analysis and Modeling of Parallel Photovoltaic Systems under Partial Shading Conditions

    Science.gov (United States)

    Buddala, Santhoshi Snigdha

    Since the industrial revolution, fossil fuels like petroleum, coal, oil, natural gas and other non-renewable energy sources have been used as the primary energy source. The consumption of fossil fuels releases various harmful gases into the atmosphere as byproducts which are hazardous in nature and they tend to deplete the protective layers and affect the overall environmental balance. Also the fossil fuels are bounded resources of energy and rapid depletion of these sources of energy, have prompted the need to investigate alternate sources of energy called renewable energy. One such promising source of renewable energy is the solar/photovoltaic energy. This work focuses on investigating a new solar array architecture with solar cells connected in parallel configuration. By retaining the structural simplicity of the parallel architecture, a theoretical small signal model of the solar cell is proposed and modeled to analyze the variations in the module parameters when subjected to partial shading conditions. Simulations were run in SPICE to validate the model implemented in Matlab. The voltage limitations of the proposed architecture are addressed by adopting a simple dc-dc boost converter and evaluating the performance of the architecture in terms of efficiencies by comparing it with the traditional architectures. SPICE simulations are used to compare the architectures and identify the best one in terms of power conversion efficiency under partial shading conditions.

  6. Partial synchronization in networks of non-linearly coupled oscillators: The Deserter Hubs Model

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, Celso, E-mail: cbnfreitas@gmail.com; Macau, Elbert, E-mail: elbert.macau@inpe.br [Associate Laboratory for Computing and Applied Mathematics - LAC, Brazilian National Institute for Space Research - INPE (Brazil); Pikovsky, Arkady, E-mail: pikovsky@uni-potsdam.de [Department of Physics and Astronomy, University of Potsdam, Germany and Department of Control Theory, Nizhni Novgorod State University, Gagarin Av. 23, 606950, Nizhni Novgorod (Russian Federation)

    2015-04-15

    We study the Deserter Hubs Model: a Kuramoto-like model of coupled identical phase oscillators on a network, where attractive and repulsive couplings are balanced dynamically due to nonlinearity of interactions. Under weak force, an oscillator tends to follow the phase of its neighbors, but if an oscillator is compelled to follow its peers by a sufficient large number of cohesive neighbors, then it actually starts to act in the opposite manner, i.e., in anti-phase with the majority. Analytic results yield that if the repulsion parameter is small enough in comparison with the degree of the maximum hub, then the full synchronization state is locally stable. Numerical experiments are performed to explore the model beyond this threshold, where the overall cohesion is lost. We report in detail partially synchronous dynamical regimes, like stationary phase-locking, multistability, periodic and chaotic states. Via statistical analysis of different network organizations like tree, scale-free, and random ones, we found a measure allowing one to predict relative abundance of partially synchronous stationary states in comparison to time-dependent ones.

  7. A simple one-step chemistry model for partially premixed hydrocarbon combustion

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Tarrazo, Eduardo [Instituto Nacional de Tecnica Aeroespacial, Madrid (Spain); Sanchez, Antonio L. [Area de Mecanica de Fluidos, Universidad Carlos III de Madrid, Leganes 28911 (Spain); Linan, Amable [ETSI Aeronauticos, Pl. Cardenal Cisneros 3, Madrid 28040 (Spain); Williams, Forman A. [Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA 92093-0411 (United States)

    2006-10-15

    This work explores the applicability of one-step irreversible Arrhenius kinetics with unity reaction order to the numerical description of partially premixed hydrocarbon combustion. Computations of planar premixed flames are used in the selection of the three model parameters: the heat of reaction q, the activation temperature T{sub a}, and the preexponential factor B. It is seen that changes in q with equivalence ratio f need to be introduced in fuel-rich combustion to describe the effect of partial fuel oxidation on the amount of heat released, leading to a universal linear variation q(f) for f>1 for all hydrocarbons. The model also employs a variable activation temperature T{sub a}(f) to mimic changes in the underlying chemistry in rich and very lean flames. The resulting chemistry description is able to reproduce propagation velocities of diluted and undiluted flames accurately over the whole flammability limit. Furthermore, computations of methane-air counterflow diffusion flames are used to test the proposed chemistry under nonpremixed conditions. The model not only predicts the critical strain rate at extinction accurately but also gives near-extinction flames with oxygen leakage, thereby overcoming known predictive limitations of one-step Arrhenius kinetics. (author)

  8. Effect of sevoflurane on the ATPase activity of hippocampal neurons in a rat model of cerebral ischemia-reperfusion injury via the cAMP-PKA signaling pathway.

    Science.gov (United States)

    Liu, Tie-Jun; Zhang, Jin-Cun; Gao, Xiao-Zeng; Tan, Zhi-Bin; Wang, Jian-Jun; Zhang, Pan-Pan; Cheng, Ai-Bin; Zhang, Shu-Bo

    2018-01-01

    We aim to investigate the effects of sevoflurane on the ATPase activity of the hippocampal neurons in rats with cerebral ischemia-reperfusion injury (IRI) via the cyclic adenosine monophosphate (cAMP) and protein kinase A (PKA) signaling pathway. Sixty rats were assigned into the normal, model and sevoflurane groups (n = 20, the latter two groups were established as focal cerebral IRI models). The ATPase activity was detected using an ultramicro Na (+)-K (+)-ATP enzyme kit. Immunohistochemical staining was used to detect the positive protein expression of cAMP and PKA. The hippocampal neurons were assigned to the normal, IRI, IRI + sevoflurane, IRI + forskolin, IRI + H89 and IRI + sevoflurane + H89 groups. qRT-PCR and Western blotting were performed for the expressions of cAMP, PKA, cAMP-responsive element-binding protein (CREB) and brain derived neurotrophic factor (BDNF). The normal and sevoflurane groups exhibited a greater positive protein expression of cAMP and PKA than the model group. Compared with the normal group, the expressions of cAMP, PKA, CREB and BDNF all reduced in the IRI, model and IRI + H89 groups. The sevoflurane group showed higher cAMP, PKA, CREB and BDNF expressions than the model group. Compared with the IRI group, ATPase activity and expressions of cAMP, PKA, CREB and BDNF all increased in the normal, IRI + sevoflurane and IRI + forskolin groups but decreased in the IRI + H89 group. It suggests that sevoflurane could enhance ATPase activity in hippocampal neurons of cerebral IRI rats through activating cAMP-PKA signaling pathway. Copyright © 2017. Published by Elsevier Taiwan.

  9. Partial corrosion casting to assess cochlear vasculature in mouse models of presbycusis and CMV infection.

    Science.gov (United States)

    Carraro, Mattia; Park, Albert H; Harrison, Robert V

    2016-02-01

    Some forms of sensorineural hearing loss involve damage or degenerative changes to the stria vascularis and/or other vascular structures in the cochlea. In animal models, many methods for anatomical assessment of cochlear vasculature exist, each with advantages and limitations. One methodology, corrosion casting, has proved useful in some species, however in the mouse model this technique is difficult to achieve because digestion of non vascular tissue results in collapse of the delicate cast specimen. We have developed a partial corrosion cast method that allows visualization of vasculature along much of the cochlear length but maintains some structural integrity of the specimen. We provide a detailed step-by-step description of this novel technique. We give some illustrative examples of the use of the method in mouse models of presbycusis and cytomegalovirus (CMV) infection. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. A comparison of partially specular radiosity and ray tracing for room acoustics modeling

    Science.gov (United States)

    Beamer, C. Walter; Muehleisen, Ralph T.

    2005-04-01

    Partially specular (PS) radiosity is an extended form of the general radiosity method. Acoustic radiosity is a form of bulk transfer of radiant acoustic energy. This bulk transfer is accomplished through a system of energy balance equations that relate the bulk energy transfer of each surface in the system to all other surfaces in the system. Until now acoustic radiosity has been limited to modeling only diffuse surface reflection. The new PS acoustic radiosity method can model all real surface types, diffuse, specular and everything in between. PS acoustic radiosity also models all real source types and distributions, not just point sources. The results of the PS acoustic radiosity method are compared to those of well known ray tracing programs. [Work supported by NSF.

  11. Modeling treatment of ischemic heart disease with partially observable Markov decision processes.

    Science.gov (United States)

    Hauskrecht, M; Fraser, H

    1998-01-01

    Diagnosis of a disease and its treatment are not separate, one-shot activities. Instead they are very often dependent and interleaved over time, mostly due to uncertainty about the underlying disease, uncertainty associated with the response of a patient to the treatment and varying cost of different diagnostic (investigative) and treatment procedures. The framework of Partially observable Markov decision processes (POMDPs) developed and used in operations research, control theory and artificial intelligence communities is particularly suitable for modeling such a complex decision process. In the paper, we show how the POMDP framework could be used to model and solve the problem of the management of patients with ischemic heart disease, and point out modeling advantages of the framework over standard decision formalisms.

  12. Review on herbal medicine on brain ischemia and reperfusion

    Directory of Open Access Journals (Sweden)

    Nahid Jivad

    2015-10-01

    Cerebral ischemia and reperfusion is known to induce the generation of reactive oxygen species that can lead to oxidative damage of proteins, membrane lipids and nucleic acids. A decrease in tissue antioxidant capacity, an increase in lipid peroxidation as well as an increase in lipid peroxidation inhibitors have been demonstrated in several models of brain ischemia. This paper reviews the number of commonly used types of herbal medicines effective for the treatment of stroke. The aim of this paper was to review evidences from controlled studies in order to discuss whether herbal medicine can be helpful in the treatment of brain ischemia and reperfusion.

  13. Effect of nano-silver hydrogel coating film on deep partial thickness scald model of rabbit

    Directory of Open Access Journals (Sweden)

    Peng Xi

    2018-05-01

    Full Text Available Objective: Observing the effect of nano-silver hydrogel coating film on deep partial thickness scald model of rabbit. Method: We prepared boiling water scalded rabbits with deep II degree scald models and applied high, medium and low doses of nano-silver hydrogel coating film for different time and area. Then we compared the difference of burned paper weight before administration and after administration model burns, burn local skin irritation points infection, skin crusting and scabs from the time, and the impact of local skin tissue morphology. Result: Rabbits deep II degree burn model successful modeling; on day 12, 18, high, medium and low doses of nano-silver hydrogel coating film significantly reduced skin irritation of rabbits infected with the integral value (P < 0.01, P < 0.05; high, medium and low doses of nano-silver hydrogel coating film group significantly decreased skin irritation, infection integral value (P < 0.01, P < 0.05; high, medium and low doses of nano-silver hydrogel coating film significantly reduced film rabbits’ scalded skin crusting time (P < 0.01, significantly shortened the rabbit skin burns from the scab time (P < 0.01, and significantly improved the treatment of skin diseases in rabbits scald model change (P < 0.01, P < 0.05. Conclusion: The nano-silver hydrogel coating film on the deep partial thickness burns has a significant therapeutic effect; external use has a significant role in wound healing. Keywords: Nano-silver hydrogel coating film, Deep degree burns, Topical, Rabbits

  14. Minocycline Effectively Protects the Rabbit's Spinal Cord From Aortic Occlusion-Related Ischemia.

    Science.gov (United States)

    Drenger, Benjamin; Fellig, Yakov; Ben-David, Dror; Mintz, Bella; Idrees, Suhel; Or, Omer; Kaplan, Leon; Ginosar, Yehuda; Barzilay, Yair

    2016-04-01

    To identify the minocycline anti-inflammatory and antiapoptotic mechanisms through which it is believed to exert spinal cord protection during aortic occlusion in the rabbit model. An animal model of aortic occlusion-related spinal cord ischemia. Randomized study with a control group and pre-ischemia and post-ischemia escalating doses of minocycline to high-dose minocycline in the presence of either hyperglycemia, a pro-apoptotic maneuver, or wortmannin, a specific phosphatidylinositol 3-kinase antagonist. Tertiary medical center and school of medicine laboratory. Laboratory animals-rabbits. Balloon obstruction of infrarenal aorta introduced via femoral artery incision. Severe hindlimb paralysis (mean Tarlov score 0.36±0.81 out of 3) was observed in all the control group animals (9 of 11 with paraplegia and 2 of 11 with paraparesis) compared with 11 of 12 neurologically intact animals (mean Tarlov score 2.58±0.90 [p = 0.001 compared with control]) in the high-dose minocycline group. This protective effect was observed partially during a state of hyperglycemia and was completely abrogated by wortmannin. Minocycline administration resulted in higher neurologic scores (p = 0.003) and a shift to viable neurons and more apoptotic-stained nuclei resulting from reduced necrosis (p = 0.001). In a rabbit model of infrarenal aortic occlusion, minocycline effectively reduced paraplegia by increasing the number of viable neurons in a dose-dependent manner. Its action was completely abrogated by inhibiting the phosphatidylinositol 3-kinase pathway and was inhibited partially by the pro-apoptotic hyperglycemia maneuver, indicating that the activation of cell salvage pathways and mitochondrial sites are possible targets of minocycline action in an ischemic spinal cord. Copyright © 2016. Published by Elsevier Inc.

  15. Evaluation of regeneration of liver function in pig model of auxiliary partial liver transplantation

    International Nuclear Information System (INIS)

    Li Jiaxin; Chen Xiaopeng; Rui Ging; Shong Qun; Chen Fangman; Lu Meijing; Chen Yongquan

    2010-01-01

    Objective: To establish a pig model of auxiliary partial liver transplantation and observe the liver function regeneration of host liver and graft. Methods: The portal vein providing for the host liver were gradually contracted; the donor hepatic veins were eng-to-side anastomosed to inferior vena cava in host caudal; graft was transplanted into the space under the host liver, part of receivers relieved portal vein angiography and color Doppler flow imaging was performed 3 days after surgery. Liver function of double livers in relievers was checked up, 3 days and 1 week after surgery respectively. Results: After surgery 10 relievers survived over 1 week, blood enzymology from hepatic vein of grafts 1 week after surgery were not ameliorative significantly compared with those 3 days after surgery (P > 0.05). Blood enzymology indexes from hepatic veins of grafts 1 week after surgery were were improved significantly compared with 3 days after surgery (P < 0.05). The graft did not reveal atrophic and gained favorable function. Conclusion: Favorable regeneration in the auxiliary partial liver transplantation model has achieved. Ideal foundation has been established for simulating and investigating human auxiliary liver transplantation. (authors)

  16. Modelling and investigation of partial wetting surfaces for drop dynamics using lattice Boltzmann method

    Science.gov (United States)

    Pravinraj, T.; Patrikar, Rajendra

    2017-07-01

    Partial wetting surfaces and its influence on the droplet movement of micro and nano scale being contemplated for many useful applications. The dynamics of the droplet usually analyzed with a multiphase lattice Boltzmann method (LBM). In this paper, the influence of partial wetting surface on the dynamics of droplet is systematically analyzed for various cases. Splitting of droplets due to chemical gradient of the surface is studied and analyses of splitting time for various widths of the strips for different Weber numbers are computed. With the proposed model one can tune the splitting volume and time by carefully choosing a strip width and droplet position. The droplet spreading on chemically heterogeneous surfaces shows that the spreading can be controlled not only by parameters of Weber number but also by tuning strip width ratio. The transportation of the droplet from hydrophobic surface to hydrophilic surface due to chemical gradient is simulated and analyzed using our hybrid thermodynamic-image processing technique. The results prove that with the progress of time the surface free energy decreases with increase in spreading area. Finally, the transportation of a droplet on microstructure gradient is demonstrated. The model explains the temporal behaviour of droplet during the spreading, recoiling and translation along with tracking of contact angle hysteresis phenomenon.

  17. An analytic, approximate method for modeling steady, three-dimensional flow to partially penetrating wells

    Science.gov (United States)

    Bakker, Mark

    2001-05-01

    An analytic, approximate solution is derived for the modeling of three-dimensional flow to partially penetrating wells. The solution is written in terms of a correction on the solution for a fully penetrating well and is obtained by dividing the aquifer up, locally, in a number of aquifer layers. The resulting system of differential equations is solved by application of the theory for multiaquifer flow. The presented approach has three major benefits. First, the solution may be applied to any groundwater model that can simulate flow to a fully penetrating well; the solution may be superimposed onto the solution for the fully penetrating well to simulate the local three-dimensional drawdown and flow field. Second, the approach is applicable to isotropic, anisotropic, and stratified aquifers and to both confined and unconfined flow. Third, the solution extends over a small area around the well only; outside this area the three-dimensional effect of the partially penetrating well is negligible, and no correction to the fully penetrating well is needed. A number of comparisons are made to existing three-dimensional, analytic solutions, including radial confined and unconfined flow and a well in a uniform flow field. It is shown that a subdivision in three layers is accurate for many practical cases; very accurate solutions are obtained with more layers.

  18. [Partial nucleotomy of the ovine disc as an in vivo model for disc degeneration].

    Science.gov (United States)

    Guder, E; Hill, S; Kandziora, F; Schnake, K J

    2009-01-01

    The aim of this study was to develop a suitable animal model for the clinical situation of progressive disc degeneration after microsurgical nucleotomy. Twenty sheep underwent standardised partial anterolateral nucleotomy at lumbar segment 3/4. After randomisation, 10 animals were sacrificed after 12 weeks (group 1). The remainder was sacrificed after 48 weeks (group 2). For radiological examination X-rays, MRI and post-mortem CT scans were performed. Lumbar discs L 3/4 with adjacent subchondral trabecular bone were harvested and analysed macroscopically and histologically. An image-analysing computer program was used to measure histomorphometric indices of bone structure. 17 segments could be evaluated. After 12 weeks (group 1) histological and radiological degenerative disc changes were noted. After 48 weeks (group 2), radiological signs in MRI reached statistical significance. Furthermore, group 2 showed significantly more osteophyte formations in CT scans. Histomorphometric changes of the disc and the adjacent vertebral bone structure suggest a significant progressive degenerative remodelling. The facet joints did not show any osteoarthrosis after 48 weeks. Partial nucleotomy of the ovine lumbar disc leads to radiological and histological signs of disc degeneration similar to those seen in humans after microsurgical nucleotomy. The presented in vivo model may be useful to evaluate new orthopaedic treatment strategies.

  19. Tricriticality in the q-neighbor Ising model on a partially duplex clique.

    Science.gov (United States)

    Chmiel, Anna; Sienkiewicz, Julian; Sznajd-Weron, Katarzyna

    2017-12-01

    We analyze a modified kinetic Ising model, a so-called q-neighbor Ising model, with Metropolis dynamics [Phys. Rev. E 92, 052105 (2015)PLEEE81539-375510.1103/PhysRevE.92.052105] on a duplex clique and a partially duplex clique. In the q-neighbor Ising model each spin interacts only with q spins randomly chosen from its whole neighborhood. In the case of a duplex clique the change of a spin is allowed only if both levels simultaneously induce this change. Due to the mean-field-like nature of the model we are able to derive the analytic form of transition probabilities and solve the corresponding master equation. The existence of the second level changes dramatically the character of the phase transition. In the case of the monoplex clique, the q-neighbor Ising model exhibits a continuous phase transition for q=3, discontinuous phase transition for q≥4, and for q=1 and q=2 the phase transition is not observed. On the other hand, in the case of the duplex clique continuous phase transitions are observed for all values of q, even for q=1 and q=2. Subsequently we introduce a partially duplex clique, parametrized by r∈[0,1], which allows us to tune the network from monoplex (r=0) to duplex (r=1). Such a generalized topology, in which a fraction r of all nodes appear on both levels, allows us to obtain the critical value of r=r^{*}(q) at which a tricriticality (switch from continuous to discontinuous phase transition) appears.

  20. Evaluation of potential changes in liver and lung tissue of rats in an ischemia-reperfusion injury model (modified pringle maneuver.

    Directory of Open Access Journals (Sweden)

    Silvio Henrique Freitas

    Full Text Available In surgical procedures involving the liver, such as transplantation, resection, and trauma, a temporary occlusion of hepatic vessels may be required. This study was designed to analyze the lesions promoted by ischemia and reperfusion injury of the hepatic pedicle, in the liver and lung, using histopathological and immunohistochemical techniques. In total, 39 Wistar rats were divided into four groups: control group (C n = 3 and ischemia groups subjected to 10, 20, and 30 minutes of hepatic pedicle clamping (I10, n = 12; I20, n = 12; I30, n = 12. Each ischemia group was subdivided into four subgroups of reperfusion (R15, n = 3; R30, n = 3; R60, n = 3; R120, n = 3, after 15, 30, 60, and 120 minutes of reperfusion, respectively. Significant differences were observed in the liver parenchyma (P 0.05. In the lung parenchyma, a significant difference was observed (P 0.05 at different times of ischemia and reperfusion. In the pulmonary parenchyma, the immunoreactivity was not specific, and was not quantified. This study demonstrated that the longer the duration of ischemia and reperfusion, the greater are the morphological lesions found in the hepatic and pulmonary parenchyma.

  1. Phase behavior and reactive transport of partial melt in heterogeneous mantle model

    Science.gov (United States)

    Jordan, J.; Hesse, M. A.

    2013-12-01

    The reactive transport of partial melt is the key process that leads to the chemical and physical differentiation of terrestrial planets and smaller celestial bodies. The essential role of the lithological heterogeneities during partial melting of the mantle is increasingly recognized. How far can enriched melts propagate while interacting with the ambient mantle? Can the melt flow emanating from a fertile heterogeneity be localized through a reactive infiltration feedback in a model without exogenous factors or contrived initial conditions? A full understanding of the role of heterogeneities requires reactive melt transport models that account for the phase behavior of major elements. Previous work on reactive transport in the mantle focuses on trace element partitioning; we present the first nonlinear chromatographic analysis of reactive melt transport in systems with binary solid solution. Our analysis shows that reactive melt transport in systems with binary solid solution leads to the formation of two separate reaction fronts: a slow melting/freezing front along which enthalpy change is dominant and a fast dissolution/precipitation front along which compositional changes are dominated by an ion-exchange process over enthalpy change. An intermediate state forms between these two fronts with a bulk-rock composition and enthalpy that are not necessarily bounded by the bulk-rock composition and enthalpy of either the enriched heterogeneity or the depleted ambient mantle. The formation of this intermediate state makes it difficult to anticipate the porosity changes and hence the stability of reaction fronts. Therefore, we develop a graphical representation for the solution that allows identification of the intermediate state by inspection, for all possible bulk-rock compositions and enthalpies of the heterogeneity and the ambient mantle. We apply the analysis to the partial melting of an enriched heterogeneity. This leads to the formation of moving precipitation

  2. Critical exponents of the transition from incoherence to partial oscillation death in the Winfree model

    International Nuclear Information System (INIS)

    Basnarkov, Lasko; Urumov, Viktor

    2009-01-01

    We consider an analytically solvable version of the Winfree model of synchronization of phase oscillators (proposed by Ariaratnam and Strogatz 2001 Phys. Rev. Lett. 86 4278). It is obtained that the transition from incoherence to a partial death state is characterized by third-order or higher phase transitions according to the Ehrenfest classification. The order of the transition depends on the shape of the distribution function for natural frequencies of oscillators in the vicinity of their lowest frequency. The corresponding critical exponents are found analytically and verified with numerical simulations of equations of motion. We also consider the generalized Winfree model with the interaction strength proportional to a power of the Kuramoto order parameter and find the domain where the critical exponent remains unchanged by this modification

  3. An economic order quantity model with nonlinear holding cost, partial backlogging and ramp-type demand

    Science.gov (United States)

    San-José, Luis A.; Sicilia, Joaquín; González-de-la-Rosa, Manuel; Febles-Acosta, Jaime

    2018-07-01

    In this article, a deterministic inventory model with a ramp-type demand depending on price and time is developed. The cumulative holding cost is assumed to be a nonlinear function of time. Shortages are allowed and are partially backlogged. Thus, the fraction of backlogged demand depends on the waiting time and on the stock-out period. The aim is to maximize the total profit per unit time. To do this, a procedure that determines the economic lot size, the optimal inventory cycle and the maximum profit is presented. The inventory system studied here extends diverse inventory models proposed in the literature. Finally, some numerical examples are provided to illustrate the theoretical results previously propounded.

  4. MR of experimental cerebral ischemia

    International Nuclear Information System (INIS)

    DeLaPaz, R.; Steinberg, G.; Rocklage, S.; Glover, G.H.

    1990-01-01

    This paper reports on MR imaging of cerebral ischemia and treatment with N-methyl-D-aspartate (NMDA) antagonists in an animal model. Forty-four New Zealand white rabbits underwent 1-hour transorbital ICA-MCA-ACA occlusion and pretreatment or immediate posttreatment with systemic dextromethorphan (DM, n = 14), dextrorphan (DX, n = 14), or normal saline (NS, n = 16). Serial MR studies (1.5 T) were performed 1--6 hours after occlusion with T1- and T2-weighted spinecho, IVIM (b = 1,352), gradient recalled acquisition in a steady-state, and chemical shift sequences (for magnetic susceptibility, T2* and T2') and DyDTPA-BMA intravenous contrast material (Salutar). Spatial correlation between MR findings, histologic findings (ischemic neuronal damage), and regional cerebral blood flow (microspheres) was done

  5. Mitochondrial dysfunction in H9c2 cells during ischemia and amelioration with Tribulus terrestris L.

    Science.gov (United States)

    Reshma, P L; Sainu, Neethu S; Mathew, Anil K; Raghu, K G

    2016-05-01

    The present study investigates the protective effect of partially characterized Tribulus terrestris L. fruit methanol extract against mitochondrial dysfunction in cell based (H9c2) myocardial ischemia model. To induce ischemia, the cells were maintained in an ischemic buffer (composition in mM -137 NaCl, 12 KCl, 0.5 MgCl2, 0.9 CaCl2, 20 HEPES, 20 2-deoxy-d-glucose, pH-6.2) at 37°C with 0.1% O2, 5% CO2, and 95% N2 in a hypoxia incubator for 1h. Cells were pretreated with various concentrations of T. terrestris L. fruit methanol extract (10 and 25μg/ml) and Cyclosporin A (1μM) for 24h prior to the induction of ischemia. Different parameters like lactate dehydrogenase release, total antioxidant capacity, glutathione content and antioxidant enzymes were investigated. Studies were conducted on mitochondria by analyzing alterations in mitochondrial membrane potential, integrity, and dynamics (fission and fusion proteins - Mfn1, Mfn2, OPA1, Drp1 and Fis1). Various biochemical processes in mitochondria like activity of electron transport chain (ETC) complexes, oxygen consumption and ATP production was measured. Ischemia for 1h caused a significant (p≤0.05) increase in LDH leakage, decrease in antioxidant activity and caused mitochondrial dysfunction. T. terrestris L. fruit methanol extract pretreatment was found effective in safeguarding mitochondria via its antioxidant potential, mediated through various bioactives. HPLC of T. terrestris L. fruit methanol extract revealed the presence of ferulic acid, phloridzin and diosgenin. T. terrestris L. fruit ameliorate ischemic insult in H9c2 cells by safeguarding mitochondrial function. This validates the use of T. terrestris L. against heart disorders. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Oscillator strength of partially ionized high-Z atom on Hartree-Fock Slater model

    International Nuclear Information System (INIS)

    Nakamura, S.; Nishikawa, T.; Takabe, H.; Mima, K.

    1991-01-01

    The Hartree-Fock Slater (HFS) model has been solved for the partially ionized gold ions generated when an intense laser light is irradiated on a gold foil target. The resultant energy levels are compared with those obtained by a simple screened hydrogenic model with l-splitting effect (SHML). It is shown that the energy levels are poorly model by SHML as the ionization level becomes higher. The resultant wave functions are used to evaluate oscillator strength of important line radiations and compared with those obtained by a simple model using hydrogenic wave functions. Its demonstrated that oscillator strength of the 4p-4d and 4d-4f lines are well modeled by the simple method, while the 4-5 transitions such as 4f-5g, 4d-5f, 4p-5d, and 4f-5p forming the so-called N-band emission are poorly modeled and HFS results less strong line emissions. (author)

  7. Prediction of Placental Barrier Permeability: A Model Based on Partial Least Squares Variable Selection Procedure

    Directory of Open Access Journals (Sweden)

    Yong-Hong Zhang

    2015-05-01

    Full Text Available Assessing the human placental barrier permeability of drugs is very important to guarantee drug safety during pregnancy. Quantitative structure–activity relationship (QSAR method was used as an effective assessing tool for the placental transfer study of drugs, while in vitro human placental perfusion is the most widely used method. In this study, the partial least squares (PLS variable selection and modeling procedure was used to pick out optimal descriptors from a pool of 620 descriptors of 65 compounds and to simultaneously develop a QSAR model between the descriptors and the placental barrier permeability expressed by the clearance indices (CI. The model was subjected to internal validation by cross-validation and y-randomization and to external validation by predicting CI values of 19 compounds. It was shown that the model developed is robust and has a good predictive potential (r2 = 0.9064, RMSE = 0.09, q2 = 0.7323, rp2 = 0.7656, RMSP = 0.14. The mechanistic interpretation of the final model was given by the high variable importance in projection values of descriptors. Using PLS procedure, we can rapidly and effectively select optimal descriptors and thus construct a model with good stability and predictability. This analysis can provide an effective tool for the high-throughput screening of the placental barrier permeability of drugs.

  8. Efficient semiparametric estimation in generalized partially linear additive models for longitudinal/clustered data

    KAUST Repository

    Cheng, Guang

    2014-02-01

    We consider efficient estimation of the Euclidean parameters in a generalized partially linear additive models for longitudinal/clustered data when multiple covariates need to be modeled nonparametrically, and propose an estimation procedure based on a spline approximation of the nonparametric part of the model and the generalized estimating equations (GEE). Although the model in consideration is natural and useful in many practical applications, the literature on this model is very limited because of challenges in dealing with dependent data for nonparametric additive models. We show that the proposed estimators are consistent and asymptotically normal even if the covariance structure is misspecified. An explicit consistent estimate of the asymptotic variance is also provided. Moreover, we derive the semiparametric efficiency score and information bound under general moment conditions. By showing that our estimators achieve the semiparametric information bound, we effectively establish their efficiency in a stronger sense than what is typically considered for GEE. The derivation of our asymptotic results relies heavily on the empirical processes tools that we develop for the longitudinal/clustered data. Numerical results are used to illustrate the finite sample performance of the proposed estimators. © 2014 ISI/BS.

  9. Alleviation of glutamate mediated neuronal insult by piroxicam in rodent model of focal cerebral ischemia: a possible mechanism of GABA agonism.

    Science.gov (United States)

    Bhattacharya, Pallab; Pandey, Anand Kumar; Paul, Sudip; Patnaik, Ranjana

    2014-12-01

    Neurotransmitter imbalance is an inevitable outcome in cerebral ischemia that leads to neuronal death. In the present study, we evaluated the effects of piroxicam, a nonsteroidal anti-inflammatory drug (NSAID), on extracellular brain glutamate and γ-aminobutyric acid (GABA) release, survival time, and neuronal cell death. Transient focal cerebral ischemia in male Charles Foster rat led to neuronal infarction and compromised intrinsic antioxidant status. Thirty-minute preadministration of piroxicam (10 mg/kg b.w.) showed a significant (P piroxicam administration in stroke rat significantly reduced (P piroxicam attenuates extracellular glutamate release and also reduces neuronal cell death due to reduction in oxidative stress in cerebral ischemia. Our results also indicate a consequent increase of extracellular GABA in brain regions administered with piroxicam, which hints that piroxicam alleviates glutamate excitotoxicity possibly by GABA agonism.

  10. Development and Validity of a Silicone Renal Tumor Model for Robotic Partial Nephrectomy Training.

    Science.gov (United States)

    Monda, Steven M; Weese, Jonathan R; Anderson, Barrett G; Vetter, Joel M; Venkatesh, Ramakrishna; Du, Kefu; Andriole, Gerald L; Figenshau, Robert S

    2018-04-01

    To provide a training tool to address the technical challenges of robot-assisted laparoscopic partial nephrectomy, we created silicone renal tumor models using 3-dimensional printed molds of a patient's kidney with a mass. In this study, we assessed the face, content, and construct validity of these models. Surgeons of different training levels completed 4 simulations on silicone renal tumor models. Participants were surveyed on the usefulness and realism of the model as a training tool. Performance was measured using operation-specific metrics, self-reported operative demands (NASA Task Load Index [NASA TLX]), and blinded expert assessment (Global Evaluative Assessment of Robotic Surgeons [GEARS]). Twenty-four participants included attending urologists, endourology fellows, urology residents, and medical students. Post-training surveys of expert participants yielded mean results of 79.2 on the realism of the model's overall feel and 90.2 on the model's overall usefulness for training. Renal artery clamp times and GEARS scores were significantly better in surgeons further in training (P ≤.005 and P ≤.025). Renal artery clamp times, preserved renal parenchyma, positive margins, NASA TLX, and GEARS scores were all found to improve across trials (P <.001, P = .025, P = .024, P ≤.020, and P ≤.006, respectively). Face, content, and construct validity were demonstrated in the use of a silicone renal tumor model in a cohort of surgeons of different training levels. Expert participants deemed the model useful and realistic. Surgeons of higher training levels performed better than less experienced surgeons in various study metrics, and improvements within individuals were observed over sequential trials. Future studies should aim to assess model predictive validity, namely, the association between model performance improvements and improvements in live surgery. Copyright © 2018 Elsevier Inc. All rights reserved.

  11. A model and variance reduction method for computing statistical outputs of stochastic elliptic partial differential equations

    International Nuclear Information System (INIS)

    Vidal-Codina, F.; Nguyen, N.C.; Giles, M.B.; Peraire, J.

    2015-01-01

    We present a model and variance reduction method for the fast and reliable computation of statistical outputs of stochastic elliptic partial differential equations. Our method consists of three main ingredients: (1) the hybridizable discontinuous Galerkin (HDG) discretization of elliptic partial differential equations (PDEs), which allows us to obtain high-order accurate solutions of the governing PDE; (2) the reduced basis method for a new HDG discretization of the underlying PDE to enable real-time solution of the parameterized PDE in the presence of stochastic parameters; and (3) a multilevel variance reduction method that exploits the statistical correlation among the different reduced basis approximations and the high-fidelity HDG discretization to accelerate the convergence of the Monte Carlo simulations. The multilevel variance reduction method provides efficient computation of the statistical outputs by shifting most of the computational burden from the high-fidelity HDG approximation to the reduced basis approximations. Furthermore, we develop a posteriori error estimates for our approximations of the statistical outputs. Based on these error estimates, we propose an algorithm for optimally choosing both the dimensions of the reduced basis approximations and the sizes of Monte Carlo samples to achieve a given error tolerance. We provide numerical examples to demonstrate the performance of the proposed method

  12. Ghost imaging and its visibility with partially coherent elliptical Gaussian Schell-model beams

    International Nuclear Information System (INIS)

    Luo, Meilan; Zhu, Weiting; Zhao, Daomu

    2015-01-01

    The performances of the ghost image and the visibility with partially coherent elliptical Gaussian Schell-model beams have been studied. In that case we have derived the condition under which the goal ghost image is achievable. Furthermore, the visibility is assessed in terms of the parameters related to the source to find that the visibility reduces with the increase of the beam size, while it is a monotonic increasing function of the transverse coherence length. More specifically, it is found that the inequalities of the source sizes in x and y directions, as well as the transverse coherence lengths, play an important role in the ghost image and the visibility. - Highlights: • We studied the ghost image and visibility with partially coherent EGSM beams. • We derived the condition under which the goal ghost image is achievable. • The visibility is assessed in terms of the parameters related to the source. • The source sizes and coherence lengths play role in the ghost image and visibility.

  13. Mechanisms of Neuroprotection from Hypoxia-Ischemia (HI) Brain Injury by Up-regulation of Cytoglobin (CYGB) in a Neonatal Rat Model*

    Science.gov (United States)

    Tian, Shu-Feng; Yang, Han-Hua; Xiao, Dan-Ping; Huang, Yue-Jun; He, Gu-Yu; Ma, Hai-Ran; Xia, Fang; Shi, Xue-Chuan

    2013-01-01

    This study was designed to investigate the expression profile of CYGB, its potential neuroprotective function, and underlying molecular mechanisms using a model of neonatal hypoxia-ischemia (HI) brain injury. Cygb mRNA and protein expression were evaluated within the first 36 h after the HI model was induced using RT-PCR and Western blotting. Cygb mRNA expression was increased at 18 h in a time-dependent manner, and its level of protein expression increased progressively in 24 h. To verify the neuroprotective effect of CYGB, a gene transfection technique was employed. Cygb cDNA and shRNA delivery adenovirus systems were established (Cygb-cDNA-ADV and Cygb-shRNA-ADV, respectively) and injected into the brains of 3-day-old rats 4 days before they were induced with HI treatment. Rats from different groups were euthanized 24 h post-HI, and brain samples were harvested. 2,3,5-Triphenyltetrazolium chloride, TUNEL, and Nissl staining indicated that an up-regulation of CYGB resulted in reduced acute brain injury. The superoxide dismutase level was found to be dependent on expression of CYGB. The Morris water maze test in 28-day-old rats demonstrated that CYGB expression was associated with improvement of long term cognitive impairment. Studies also demonstrated that CYGB can up-regulate mRNA and protein levels of VEGF and increase both the density and diameter of the microvessels but inhibits activation of caspase-2 and -3. Thus, this is the first in vivo study focusing on the neuroprotective role of CYGB. The reduction of neonatal HI injury by CYGB may be due in part to antioxidant and antiapoptotic mechanisms and by promoting angiogenesis. PMID:23585565

  14. The effects of escitalopram on myocardial apoptosis and the expression of Bax and Bcl-2 during myocardial ischemia/reperfusion in a model of rats with depression.

    Science.gov (United States)

    Wang, Yiming; Zhang, Hongming; Chai, Fangxian; Liu, Xingde; Berk, Michael

    2014-12-04

    Major depressive disorder (MDD) is an independent risk factor for coronary heart disease (CHD), and influences the occurrence and prognosis of cardiovascular events. Although there is evidence that antidepressants may be cardioprotective after acute myocardial infarction (AMI) comorbid with MDD, the operative pathophysiological mechanisms remain unclear. Our aim was therefore to explore the molecular mechanisms of escitalopram on myocardial apoptosis and the expression of Bax and Bcl-2 in a rat model of depression during myocardial ischemia/reperfusion (I/R). Rats were divided randomly into 3 groups (n = 8): D group (depression), DI/R group (depression with myocardial I/R) and escitalopram + DI/R group. The rats in all three groups underwent the same chronic mild stress and separation for 21 days, at the same time, in the escitalopram + DI/R group, rats were administered escitalopram by gavage (10 mg/kg/day). Ligation of the rat's left anterior descending branch was done in the myocardial I/R model. Following which behavioral tests were done. The size of the myocardial infarction was detected using 1.5% TTC dye. The Tunel method was used to detect apoptotic myocardial cells, and both the Rt-PCR method and immunohistochemical techniques were used to detect the expression of Bcl-2 and Bax. Compared with the D and DI/R groups, rats in Escitalopram + DI/R group showed significantly increased movements and sucrose consumption (P escitalopram + DI/R group was significantly decreased (P escitalopram + DI/R groups (P escitalopram + DI/R group were significantly decreased (P escitalopram + DI/R group (P escitalopram. This suggests that clinically escitalopram may have a direct cardioprotective after acute myocardial infarction.

  15. Inhibition of tumor necrosis factor alpha reduces the outgrowth of hepatic micrometastasis of colorectal tumors in a mouse model of liver ischemia-reperfusion injury.

    Science.gov (United States)

    Jiao, Shu-Fan; Sun, Kai; Chen, Xiao-Jing; Zhao, Xue; Cai, Ning; Liu, Yan-Jun; Xu, Long-Mei; Kong, Xian-Ming; Wei, Li-Xin

    2014-01-08

    Patients with colorectal cancer (CRC) often develop liver metastases, in which case surgery is considered the only potentially curative treatment option. However, liver surgery is associated with a risk of ischemia-reperfusion (IR) injury, which is thought to promote the growth of colorectal liver metastases. The influence of IR-induced tumor necrosis factor alpha (TNF-α) elevation in the process still is unknown. To investigate the role of TNF-α in the growth of pre-existing micrometastases in the liver following IR, we used a mouse model of colorectal liver metastases. In this model, mice received IR treatment seven days after intrasplenic injections of colorectal CT26 cells. Prior to IR treatment, either TNF-α blocker Enbrel or low-dose TNF-α, which could inhibit IR-induced TNF-α elevation, was administered by intraperitoneal injection. Hepatic IR treatment significantly promoted CT26 tumor growth in the liver, but either Enbrel or low-dose TNF-α pretreatment reversed this trend. Further studies showed that the CT26 + IR group prominently increased the levels of ALT and AST, liver necrosis, inflammatory infiltration and the expressions of hepatic IL-6, MMP9 and E-selectin compared to those of CT26 group. Inhibition of TNF-α elevation remarkably attenuated the increases of these liver inflammatory damage indicators and tumor-promoting factors. These findings suggested that inhibition of TNF-α elevation delayed the IR-enhanced outgrowth of colorectal liver metastases by reducing IR-induced inflammatory damage and the formation of tumor-promoting microenvironments. Both Enbrel and low-dose TNF-α represented the potential therapeutic approaches for the protection of colorectal liver metastatic patients against IR injury-induced growth of liver micrometastases foci.

  16. The effects of voluntary, involuntary, and forced exercises on brain-derived neurotrophic factor and motor function recovery: a rat brain ischemia model.

    Directory of Open Access Journals (Sweden)

    Zheng Ke

    Full Text Available BACKGROUND: Stroke rehabilitation with different exercise paradigms has been investigated, but which one is more effective in facilitating motor recovery and up-regulating brain neurotrophic factor (BDNF after brain ischemia would be interesting to clinicians and patients. Voluntary exercise, forced exercise, and involuntary muscle movement caused by functional electrical stimulation (FES have been individually demonstrated effective as stroke rehabilitation intervention. The aim of this study was to investigate the effects of these three common interventions on brain BDNF changes and motor recovery levels using a rat ischemic stroke model. METHODOLOGY/PRINCIPAL FINDINGS: One hundred and seventeen Sprague-Dawley rats were randomly distributed into four groups: Control (Con, Voluntary exercise of wheel running (V-Ex, Forced exercise of treadmill running (F-Ex, and Involuntary exercise of FES (I-Ex with implanted electrodes placed in two hind limb muscles on the affected side to mimic gait-like walking pattern during stimulation. Ischemic stroke was induced in all rats with the middle cerebral artery occlusion/reperfusion model and fifty-seven rats had motor deficits after stroke. Twenty-four hours after reperfusion, rats were arranged to their intervention programs. De Ryck's behavioral test was conducted daily during the 7-day intervention as an evaluation tool of motor recovery. Serum corticosterone concentration and BDNF levels in the hippocampus, striatum, and cortex were measured after the rats were sacrificed. V-Ex had significantly better motor recovery in the behavioral test. V-Ex also had significantly higher hippocampal BDNF concentration than F-Ex and Con. F-Ex had significantly higher serum corticosterone level than other groups. CONCLUSION/SIGNIFICANCE: Voluntary exercise is the most effective intervention in upregulating the hippocampal BDNF level, and facilitating motor recovery. Rats that exercised voluntarily also showed less

  17. Gamma-Ray Emission Tomography: Modeling and Evaluation of Partial-Defect Testing Capabilities

    International Nuclear Information System (INIS)

    Jacobsson Svard, S.; Jansson, P.; Davour, A.; Grape, S.; White, T.A.; Smith, L.E.; Deshmukh, N.; Wittman, R.S.; Mozin, V.; Trellue, H.

    2015-01-01

    Gamma emission tomography (GET) for spent nuclear fuel verification is the subject for IAEA MSP project JNT1955. In line with IAEA Safeguards R&D plan 2012-2023, the aim of this effort is to ''develop more sensitive and less intrusive alternatives to existing NDA instruments to perform partial defect test on spent fuel assembly prior to transfer to difficult to access storage''. The current viability study constitutes the first phase of three, with evaluation and decision points between each phase. Two verification objectives have been identified; (1) counting of fuel pins in tomographic images without any a priori knowledge of the fuel assembly under study, and (2) quantitative measurements of pinby- pin properties, e.g., burnup, for the detection of anomalies and/or verification of operator-declared data. Previous measurements performed in Sweden and Finland have proven GET highly promising for detecting removed or substituted fuel rods in BWR and VVER-440 fuel assemblies even down to the individual fuel rod level. The current project adds to previous experiences by pursuing a quantitative assessment of the capabilities of GET for partial defect detection, across a broad range of potential IAEA applications, fuel types and fuel parameters. A modelling and performance-evaluation framework has been developed to provide quantitative GET performance predictions, incorporating burn-up and cooling-time calculations, Monte Carlo radiation-transport and detector-response modelling, GET instrument definitions (existing and notional) and tomographic reconstruction algorithms, which use recorded gamma-ray intensities to produce images of the fuel's internal source distribution or conclusive rod-by-rod data. The framework also comprises image-processing algorithms and performance metrics that recognize the inherent tradeoff between the probability of detecting missing pins and the false-alarm rate. Here, the modelling and analysis framework is

  18. Prediction of CO concentrations based on a hybrid Partial Least Square and Support Vector Machine model

    Science.gov (United States)

    Yeganeh, B.; Motlagh, M. Shafie Pour; Rashidi, Y.; Kamalan, H.

    2012-08-01

    Due to the health impacts caused by exposures to air pollutants in urban areas, monitoring and forecasting of air quality parameters have become popular as an important topic in atmospheric and environmental research today. The knowledge on the dynamics and complexity of air pollutants behavior has made artificial intelligence models as a useful tool for a more accurate pollutant concentration prediction. This paper focuses on an innovative method of daily air pollution prediction using combination of Support Vector Machine (SVM) as predictor and Partial Least Square (PLS) as a data selection tool based on the measured values of CO concentrations. The CO concentrations of Rey monitoring station in the south of Tehran, from Jan. 2007 to Feb. 2011, have been used to test the effectiveness of this method. The hourly CO concentrations have been predicted using the SVM and the hybrid PLS-SVM models. Similarly, daily CO concentrations have been predicted based on the aforementioned four years measured data. Results demonstrated that both models have good prediction ability; however the hybrid PLS-SVM has better accuracy. In the analysis presented in this paper, statistic estimators including relative mean errors, root mean squared errors and the mean absolute relative error have been employed to compare performances of the models. It has been concluded that the errors decrease after size reduction and coefficients of determination increase from 56 to 81% for SVM model to 65-85% for hybrid PLS-SVM model respectively. Also it was found that the hybrid PLS-SVM model required lower computational time than SVM model as expected, hence supporting the more accurate and faster prediction ability of hybrid PLS-SVM model.

  19. Real-time characterization of partially observed epidemics using surrogate models.

    Energy Technology Data Exchange (ETDEWEB)

    Safta, Cosmin; Ray, Jaideep; Lefantzi, Sophia; Crary, David (Applied Research Associates, Arlington, VA); Sargsyan, Khachik; Cheng, Karen (Applied Research Associates, Arlington, VA)

    2011-09-01

    We present a statistical method, predicated on the use of surrogate models, for the 'real-time' characterization of partially observed epidemics. Observations consist of counts of symptomatic patients, diagnosed with the disease, that may be available in the early epoch of an ongoing outbreak. Characterization, in this context, refers to estimation of epidemiological parameters that can be used to provide short-term forecasts of the ongoing epidemic, as well as to provide gross information on the dynamics of the etiologic agent in the affected population e.g., the time-dependent infection rate. The characterization problem is formulated as a Bayesian inverse problem, and epidemiological parameters are estimated as distributions using a Markov chain Monte Carlo (MCMC) method, thus quantifying the uncertainty in the estimates. In some cases, the inverse problem can be computationally expensive, primarily due to the epidemic simulator used inside the inversion algorithm. We present a method, based on replacing the epidemiological model with computationally inexpensive surrogates, that can reduce the computational time to minutes, without a significant loss of accuracy. The surrogates are created by projecting the output of an epidemiological model on a set of polynomial chaos bases; thereafter, computations involving the surrogate model reduce to evaluations of a polynomial. We find that the epidemic characterizations obtained with the surrogate models is very close to that obtained with the original model. We also find that the number of projections required to construct a surrogate model is O(10)-O(10{sup 2}) less than the number of samples required by the MCMC to construct a stationary posterior distribution; thus, depending upon the epidemiological models in question, it may be possible to omit the offline creation and caching of surrogate models, prior to their use in an inverse problem. The technique is demonstrated on synthetic data as well as

  20. A Partial Proportional Odds Model for Pedestrian Crashes at Mid-Blocks in Melbourne Metropolitan Area

    Directory of Open Access Journals (Sweden)

    Toran Pour Alireza

    2016-01-01

    Full Text Available Pedestrian crashes account for 11% of all reported traffic crashes in Melbourne metropolitan area between 2004 and 2013. There are very limited studies on pedestrian accidents at mid-blocks. Mid-block crashes account for about 46% of the total pedestrian crashes in Melbourne metropolitan area. Meanwhile, about 50% of all pedestrian fatalities occur at mid-blocks. In this research, Partial Proportional Odds (PPO model is applied to examine vehicle-pedestrian crash severity at mid-blocks in Melbourne metropolitan area. The PPO model is a logistic regression model that allows the covariates that meet the proportional odds assumption to affect different crash severity levels with the same magnitude; whereas the covariates that do not meet the proportional odds assumption can have different effects on different severity levels. In this research vehicle-pedestrian crashes at mid-blocks are analysed for first time. In addition, some factors such as distance of crashes to public transport stops, average road slope and some social characteristics are considered to develop the model in this research for first time. Results of PPO model show that speed limit, light condition, pedestrian age and gender, and vehicle type are the most significant factors that influence vehicle-pedestrian crash severity at mid-blocks.

  1. The Occupancy Rate Modeling of Kendari Hotel Room using Mexican Hat Transformation and Partial Least Squares

    Directory of Open Access Journals (Sweden)

    Margaretha Ohyver

    2016-12-01

    Full Text Available Partial Least Squares (PLS method was developed in 1960 by Herman Wold. The method particularly suits with construct a regression model when the number of independent variables is many and highly collinear. The PLS can be combined with other methods, one of which is a Continuous Wavelet Transformation (CWT. By considering that the presence of outliers can lead to a less reliable model, and this kind of transformation may be required at a stage of pre-processing, the data is free of noise or outliers. Based on the previous study, Kendari hotel room occupancy rate was affected by the outlier, and it had a low value of R2. Therefore, this research aimed to obtain a good model by combining the PLS method and CWT transformation using the Mexican Hats them other wavelet of CWT. The research concludes that merging the PLS and the Mexican Hat transformation has resulted in a better model compared to the model that combined the PLS and the Haar wavelet transformation as shown in the previous study. The research shows that by changing the mother of the wavelet, the value of R2 can be improved significantly. The result provides information on how to increase the value of R2. The other advantage is the information for hotel managements to notice the age of the hotel, the maximum rates, the facilities, and the number of rooms to increase the number of visitors.

  2. Inhibition of microRNA-153 protects neurons against ischemia/reperfusion injury in an oxygen-glucose deprivation and reoxygenation cellular model by regulating Nrf2/HO-1 signaling.

    Science.gov (United States)

    Ji, Qiong; Gao, Jianbo; Zheng, Yan; Liu, Xueli; Zhou, Qiangqiang; Shi, Canxia; Yao, Meng; Chen, Xia

    2017-07-01

    MicroRNAs are emerging as critical regulators in cerebral ischemia/reperfusion injury; however, their exact roles remain poorly understood. miR-153 is reported to be a neuron-related miRNA involved in neuroprotection. In this study, we aimed to investigate the precise role of miR-153 in regulating neuron survival during cerebral ischemia/reperfusion injury using an oxygen-glucose deprivation and reoxygenation (OGD/R) cellular model. We found that miR-153 was significantly upregulated in neurons subjected to OGD/R treatment. Inhibition of miR-153 significantly attenuated OGD/R-induced injury and oxidative stress in neurons. Nuclear factor erythroid 2-related factor 2 (Nrf2) was identified as a target gene of miR-153. Inhibition of miR-153 significantly promoted the expression of Nrf2 and heme oxygenase-1 (HO-1). However, silencing of Nrf2 significantly blocked the protective effects of miR-153 inhibition. Our study indicates that the inhibition of miR-153 protects neurons against OGD/R-induced injury by regulating Nrf2/HO-1 signaling and suggests a potential therapeutic target for cerebral ischemia/reperfusion injury. © 2017 Wiley Periodicals, Inc.

  3. Comparative study of non-premixed and partially-premixed combustion simulations in a realistic Tay model combustor

    OpenAIRE

    Zhang, K.; Ghobadian, A.; Nouri, J. M.

    2017-01-01

    A comparative study of two combustion models based on non-premixed assumption and partially premixed assumptions using the overall models of Zimont Turbulent Flame Speed Closure Method (ZTFSC) and Extended Coherent Flamelet Method (ECFM) are conducted through Reynolds stress turbulence modelling of Tay model gas turbine combustor for the first time. The Tay model combustor retains all essential features of a realistic gas turbine combustor. It is seen that the non-premixed combustion model fa...

  4. Application of the chronic constriction injury of the partial sciatic nerve model to assess acupuncture analgesia

    Directory of Open Access Journals (Sweden)

    Zhi MJ

    2017-09-01

    Full Text Available Mu-Jun Zhi,1,2,* Kun Liu,1,* Zhou-Li Zheng,1,3 Xun He,1 Tie Li,2 Guang Sun,1,2 Meng Zhang,4 Fu-Chun Wang,2 Xin-Yan Gao,1 Bing Zhu1 1Department of Physiology, Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, People’s Republic of China; 2College of Acupuncture and Moxibustion, Changchun University of Chinese Medicine, Changchun, People’s Republic of China; 3College of Acupuncture and Moxibution, Shaanxi University of Chinese Medicine, People’s Republic of China; 4Department of Chinese Medicine, Dongli Hospital of Traditional Chinese Medicine, Tianjin, People’s Republic of China *These authors contributed equally to this work Purpose: To validate and explore the application of a rat model of chronic constriction injury to the partial sciatic nerve in investigation of acupuncture analgesia.Methods: Chronic constriction injury of the sciatic nerve (CCI and chronic constriction injury of the partial sciatic nerve (CCIp models were generated by ligating either the sciatic nerve trunk or its branches in rats. Both models were evaluated via paw mechanical withdrawal latency (PMWL, paw mechanical withdrawal threshold (PMWT, nociceptive reflex-induced electromyogram (C-fiber reflex EMG, and dorsal root ganglion immunohistochemistry. Electroacupuncture (EA was performed at GB30 to study the analgesic effects on neuropathic pain and the underlying mechanisms.Results: Following ligation of the common peroneal and tibial nerves, CCIp rats exhibited hindlimb dysfunction, hind paw shrinkage and lameness, mirroring those of CCI rats (generated by ligating the sciatic nerve trunk. Compared to presurgery measurements, CCIp and CCI modeling significantly decreased the PMWL and PMWT. EA at GB30 increased the PMWL and PMWT in both CCI and CCIp rats. Calcitonin gene-related polypeptide and substance P expressions were apparently increased in both CCI and CCIp groups, but were not different from each other. The C

  5. Robust estimation of partially linear models for longitudinal data with dropouts and measurement error.

    Science.gov (United States)

    Qin, Guoyou; Zhang, Jiajia; Zhu, Zhongyi; Fung, Wing

    2016-12-20

    Outliers, measurement error, and missing data are commonly seen in longitudinal data because of its data collection process. However, no method can address all three of these issues simultaneously. This paper focuses on the robust estimation of partially linear models for longitudinal data with dropouts and measurement error. A new robust estimating equation, simultaneously tackling outliers, measurement error, and missingness, is proposed. The asymptotic properties of the proposed estimator are established under some regularity conditions. The proposed method is easy to implement in practice by utilizing the existing standard generalized estimating equations algorithms. The comprehensive simulation studies show the strength of the proposed method in dealing with longitudinal data with all three features. Finally, the proposed method is applied to data from the Lifestyle Education for Activity and Nutrition study and confirms the effectiveness of the intervention in producing weight loss at month 9. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  6. Success of mainstream partial nitritation/anammox demands integration of engineering, microbiome and modeling insights.

    Science.gov (United States)

    Agrawal, Shelesh; Seuntjens, Dries; Cocker, Pieter De; Lackner, Susanne; Vlaeminck, Siegfried E

    2018-04-01

    Twenty years ago, mainstream partial nitritation/anammox (PN/A) was conceptually proposed as pivotal for a more sustainable treatment of municipal wastewater. Its economic potential spurred research, yet practice awaits a comprehensive recipe for microbial resource management. Implementing mainstream PN/A requires transferable and operable ways to steer microbial competition as to meet discharge requirements on a year-round basis at satisfactory conversion rates. In essence, the competition for nitrogen, organic carbon and oxygen is grouped into 'ON/OFF' (suppression/promotion) and 'IN/OUT' (wash-out/retention and seeding) strategies, selecting for desirable conversions and microbes. Some insights need mechanistic understanding, while empirical observations suffice elsewhere. The provided methodological R&D framework integrates insights in engineering, microbiome and modeling. Such synergism should catalyze the implementation of energy-positive sewage treatment. Copyright © 2018 Elsevier Ltd. All rights reserved.

  7. New Inference Procedures for Semiparametric Varying-Coefficient Partially Linear Cox Models

    Directory of Open Access Journals (Sweden)

    Yunbei Ma

    2014-01-01

    Full Text Available In biomedical research, one major objective is to identify risk factors and study their risk impacts, as this identification can help clinicians to both properly make a decision and increase efficiency of treatments and resource allocation. A two-step penalized-based procedure is proposed to select linear regression coefficients for linear components and to identify significant nonparametric varying-coefficient functions for semiparametric varying-coefficient partially linear Cox models. It is shown that the penalized-based resulting estimators of the linear regression coefficients are asymptotically normal and have oracle properties, and the resulting estimators of the varying-coefficient functions have optimal convergence rates. A simulation study and an empirical example are presented for illustration.

  8. CMS Partial Releases Model, Tools, and Applications. Online and Framework-Light Releases

    CERN Document Server

    Jones, Christopher D; Meschi, Emilio; Shahzad Muzaffar; Andreas Pfeiffer; Ratnikova, Natalia; Sexton-Kennedy, Elizabeth

    2009-01-01

    The CMS Software project CMSSW embraces more than a thousand packages organized in subsystems for analysis, event display, reconstruction, simulation, detector description, data formats, framework, utilities and tools. The release integration process is highly automated by using tools developed or adopted by CMS. Packaging in rpm format is a built-in step in the software build process. For several well-defined applications it is highly desirable to have only a subset of the CMSSW full package bundle. For example, High Level Trigger algorithms that run on the Online farm, and need to be rebuilt in a special way, require no simulation, event display, or analysis packages. Physics analysis applications in Root environment require only a few core libraries and the description of CMS specific data formats. We present a model of CMS Partial Releases, used for preparation of the customized CMS software builds, including description of the tools used, the implementation, and how we deal with technical challenges, suc...

  9. [18F]DPA-714: direct comparison with [11C]PK11195 in a model of cerebral ischemia in rats.

    Directory of Open Access Journals (Sweden)

    Hervé Boutin

    Full Text Available PURPOSE: Neuroinflammation is involved in several brain disorders and can be monitored through expression of the translocator protein 18 kDa (TSPO on activated microglia. In recent years, several new PET radioligands for TSPO have been evaluated in disease models. [(18F]DPA-714 is a TSPO radiotracer with great promise; however results vary between different experimental models of neuroinflammation. To further examine the potential of [(18F]DPA-714, it was compared directly to [(11C]PK11195 in experimental cerebral ischaemia in rats. METHODS: Under anaesthesia, the middle cerebral artery of adult rats was occluded for 60 min using the filament model. Rats were allowed recovery for 5 to 7 days before one hour dynamic PET scans with [(11C]PK11195 and/or [(18F]DPA-714 under anaesthesia. RESULTS: Uptake of [(11C]PK11195 vs [(18F]DPA-714 in the ischemic lesion was similar (core/contralateral ratio: 2.84±0.67 vs 2.28±0.34 respectively, but severity of the brain ischemia and hence ligand uptake in the lesion appeared to vary greatly between animals scanned with [(11C]PK11195 or with [(18F]DPA-714. To solve this issue of inter-individual variability, we performed a direct comparison of [(11C]PK11195 and [(18F]DPA-714 by scanning the same animals sequentially with both tracers within 24 h. In this direct comparison, the core/contralateral ratio (3.35±1.21 vs 4.66±2.50 for [(11C]PK11195 vs [(18F]DPA-714 respectively showed a significantly better signal-to-noise ratio (1.6 (1.3-1.9, 95%CI fold by linear regression for [(18F]DPA-714. CONCLUSIONS: In a clinically relevant model of neuroinflammation, uptake for both radiotracers appeared to be similar at first, but a high variability was observed in our model. Therefore, to truly compare tracers in such models, we performed scans with both tracers in the same animals. By doing so, our result demonstrated that [(18F]DPA-714 displayed a higher signal-to-noise ratio than [(11C]PK11195. Our results suggest

  10. [18F]DPA-714: Direct comparison with [11C]PK11195 in a model of cerebral ischemia in rats

    International Nuclear Information System (INIS)

    Boutin, Herve; Prenant, Christian; Smigova, Alison; Cawthorne, Christopher; Brown, Gavin; Herholz, Karl; Maroy, Renaud; Galea, James; Greenhalgh, Andrew D.; Rothwell, Nancy J.; Julyan, Peter; Wilkinson, Shane M.; Banister, Samuel D.; Kassiou, Michael

    2013-01-01

    Neuro-inflammation is involved in several brain disorders and can be monitored through expression of the translocator protein 18 kDa (TSPO) on activated micro-glia. In recent years, several new PET radioligands for TSPO have been evaluated in disease models. [ 18 F]DPA-714 is a TSPO radiotracer with great promise; however results vary between different experimental models of neuro-inflammation. To further examine the potential of [ 18 F]DPA-714, it was compared directly to [ 11 C]PK11195 in experimental cerebral ischaemia in rats. Under anaesthesia, the middle cerebral artery of adult rats was occluded for 60 min using the filament model. Rats were allowed recovery for 5 to 7 days before one hour dynamic PET scans with [ 11 C]PK11195 and/or [ 18 F]DPA-714 under anaesthesia. Uptake of [ 11 C]PK11195 vs [ 18 F]DPA-714 in the ischemic lesion was similar (core/contralateral ratio: 2.8460.67 vs 2.2860.34 respectively), but severity of the brain ischemia and hence ligand uptake in the lesion appeared to vary greatly between animals scanned with [ 11 C]PK11195 or with [ 18 F]DPA-714. To solve this issue of inter-individual variability, we performed a direct comparison of [ 11 C]PK11195 and [ 18 F]DPA-714 by scanning the same animals sequentially with both tracers within 24 h. In this direct comparison, the core/contralateral ratio (3.3561.21 vs 4.6662.50 for [ 11 C]PK11195 vs [ 18 F]DPA-714 respectively) showed a significantly better signal-to-noise ratio (1.6 (1.3-1.9, 95%CI) fold by linear regression) for [ 18 F]DPA-714. In a clinically relevant model of neuro-inflammation, uptake for both radiotracers appeared to be similar at first, but a high variability was observed in our model. Therefore, to truly compare tracers in such models, we performed scans with both tracers in the same animals. By doing so, our result demonstrated that [ 18 F]DPA-714 displayed a higher signal-to-noise ratio than [ 11 C]PK11195. Our results suggest that, with the longer half-life of [ 18 F

  11. A frictionally and hydraulically constrained model of the convectively driven mean flow in partially enclosed seas

    Science.gov (United States)

    Maxworthy, T.

    1997-08-01

    A simple three-layer model of the dynamics of partially enclosed seas, driven by a surface buoyancy flux, is presented. It contains two major elements, a hydraulic constraint at the exit contraction and friction in the interior of the main body of the sea; both together determine the vertical structure and magnitudes of the interior flow variables, i.e. velocity and density. Application of the model to the large-scale dynamics of the Red Sea gives results that are not in disagreement with observation once the model is applied, also, to predict the dense outflow from the Gulf of Suez. The latter appears to be the agent responsible for the formation of dense bottom water in this system. Also, the model is reasonably successful in predicting the density of the outflow from the Persian Gulf, and can be applied to any number of other examples of convectively driven flow in long, narrow channels, with or without sills and constrictions at their exits.

  12. Research on odor interaction between aldehyde compounds via a partial differential equation (PDE) model.

    Science.gov (United States)

    Yan, Luchun; Liu, Jiemin; Qu, Chen; Gu, Xingye; Zhao, Xia

    2015-01-28

    In order to explore the odor interaction of binary odor mixtures, a series of odor intensity evaluation tests were performed using both individual components and binary mixtures of aldehydes. Based on the linear relation between the logarithm of odor activity value and odor intensity of individual substances, the relationship between concentrations of individual constituents and their joint odor intensity was investigated by employing a partial differential equation (PDE) model. The obtained results showed that the binary odor interaction was mainly influenced by the mixing ratio of two constituents, but not the concentration level of an odor sample. Besides, an extended PDE model was also proposed on the basis of the above experiments. Through a series of odor intensity matching tests for several different binary odor mixtures, the extended PDE model was proved effective at odor intensity prediction. Furthermore, odorants of the same chemical group and similar odor type exhibited similar characteristics in the binary odor interaction. The overall results suggested that the PDE model is a more interpretable way of demonstrating the odor interactions of binary odor mixtures.

  13. Nitrous Oxide Production in a Granule-based Partial Nitritation Reactor: A Model-based Evaluation.

    Science.gov (United States)

    Peng, Lai; Sun, Jing; Liu, Yiwen; Dai, Xiaohu; Ni, Bing-Jie

    2017-04-03

    Sustainable wastewater treatment has been attracting increasing attentions over the past decades. However, the production of nitrous oxide (N 2 O), a potent GHG, from the energy-efficient granule-based autotrophic nitrogen removal is largely unknown. This study applied a previously established N 2 O model, which incorporated two N 2 O production pathways by ammonia-oxidizing bacteria (AOB) (AOB denitrification and the hydroxylamine (NH 2 OH) oxidation). The two-pathway model was used to describe N 2 O production from a granule-based partial nitritation (PN) reactor and provide insights into the N 2 O distribution inside granules. The model was evaluated by comparing simulation results with N 2 O monitoring profiles as well as isotopic measurement data from the PN reactor. The model demonstrated its good predictive ability against N 2 O dynamics and provided useful information about the shift of N 2 O production pathways inside granules for the first time. The simulation results indicated that the increase of oxygen concentration and granule size would significantly enhance N 2 O production. The results further revealed a linear relationship between N 2 O production and ammonia oxidation rate (AOR) (R 2  = 0.99) under the conditions of varying oxygen levels and granule diameters, suggesting that bulk oxygen and granule size may exert an indirect effect on N 2 O production by causing a change in AOR.

  14. Statistical mechanics of normal grain growth in one dimension: A partial integro-differential equation model

    International Nuclear Information System (INIS)

    Ng, Felix S.L.

    2016-01-01

    We develop a statistical-mechanical model of one-dimensional normal grain growth that does not require any drift-velocity parameterization for grain size, such as used in the continuity equation of traditional mean-field theories. The model tracks the population by considering grain sizes in neighbour pairs; the probability of a pair having neighbours of certain sizes is determined by the size-frequency distribution of all pairs. Accordingly, the evolution obeys a partial integro-differential equation (PIDE) over ‘grain size versus neighbour grain size’ space, so that the grain-size distribution is a projection of the PIDE's solution. This model, which is applicable before as well as after statistically self-similar grain growth has been reached, shows that the traditional continuity equation is invalid outside this state. During statistically self-similar growth, the PIDE correctly predicts the coarsening rate, invariant grain-size distribution and spatial grain size correlations observed in direct simulations. The PIDE is then reducible to the standard continuity equation, and we derive an explicit expression for the drift velocity. It should be possible to formulate similar parameterization-free models of normal grain growth in two and three dimensions.

  15. Modeling of strongly heat-driven flow in partially saturated fractured porous media

    International Nuclear Information System (INIS)

    Pruess, K.; Tsang, Y.W.; Wang, J.S.Y.

    1985-01-01

    The authors have performed modeling studies on the simultaneous transport of heat, liquid water, vapor, and air in partially saturated fractured porous media, with particular emphasis on strongly heat-driven flow. The presence of fractures makes the transport problem very complex, both in terms of flow geometry and physics. The numerical simulator used for their flow calculations takes into account most of the physical effects which are important in multi-phase fluid and heat flow. It has provisions to handle the extreme non-linearities which arise in phase transitions, component disappearances, and capillary discontinuities at fracture faces. They model a region around an infinite linear string of nuclear waste canisters, taking into account both the discrete fractures and the porous matrix. From an analysis of the results obtained with explicit fractures, they develop equivalent continuum models which can reproduce the temperature, saturation, and pressure variation, and gas and liquid flow rates of the discrete fracture-porous matrix calculations. The equivalent continuum approach makes use of a generalized relative permeability concept to take into account the fracture effects. This results in a substantial simplification of the flow problem which makes larger scale modeling of complicated unsaturated fractured porous systems feasible. Potential applications for regional scale simulations and limitations of the continuum approach are discussed. 27 references, 13 figures, 2 tables

  16. Processes, mechanisms, parameters, and modeling approaches for partially saturated flow in soil and rock media

    International Nuclear Information System (INIS)

    Wang, J.S.Y.; Narasimhan, T.N.

    1993-06-01

    This report discusses conceptual models and mathematical equations, analyzes distributions and correlations among hydrological parameters of soils and tuff, introduces new path integration approaches, and outlines scaling procedures to model potential-driven fluid flow in heterogeneous media. To properly model the transition from fracture-dominated flow under saturated conditions to matrix-dominated flow under partially saturated conditions, characteristic curves and permeability functions for fractures and matrix need to be improved and validated. Couplings from two-phase flow, heat transfer, solute transport, and rock deformation to liquid flow are also important. For stochastic modeling of alternating units of welded and nonwelded tuff or formations bounded by fault zones, correlations and constraints on average values of saturated permeability and air entry scaling factor between different units need to be imposed to avoid unlikely combinations of parameters and predictions. Large-scale simulations require efficient and verifiable numerical algorithms. New path integration approaches based on postulates of minimum work and mass conservation to solve flow geometry and potential distribution simultaneously are introduced. This verifiable integral approach, together with fractal scaling procedures to generate statistical realizations with parameter distribution, correlation, and scaling taken into account, can be used to quantify uncertainties and generate the cumulative distribution function for groundwater travel times

  17. Internalisation of external costs in the Polish power generation sector: A partial equilibrium model

    International Nuclear Information System (INIS)

    Kudelko, Mariusz

    2006-01-01

    This paper presents a methodical framework, which is the basis for the economic analysis of the mid-term planning of development of the Polish energy system. The description of the partial equilibrium model and its results are demonstrated for different scenarios applied. The model predicts the generation, investment and pricing of mid-term decisions that refer to the Polish electricity and heat markets. The current structure of the Polish energy sector is characterised by interactions between the supply and demand sides of the energy sector. The supply side regards possibilities to deliver fuels from domestic and import sources and their conversion through transformation processes. Public power plants, public CHP plants, industry CHP plants and municipal heat plants represent the main producers of energy in Poland. Demand is characterised by the major energy consumers, i.e. industry and construction, transport, agriculture, trade and services, individual consumers and export. The relationships between the domestic electricity and heat markets are modelled taking into account external costs estimates. The volume and structure of energy production, electricity and heat prices, emissions, external costs and social welfare of different scenarios are presented. Results of the model demonstrate that the internalisation of external costs through the increase in energy prices implies significant improvement in social welfare

  18. Modeling of strongly heat-driven flow in partially saturated fractured porous media

    International Nuclear Information System (INIS)

    Pruess, K.; Tsang, Y.W.; Wang, J.S.Y.

    1984-10-01

    We have performed modeling studies on the simultaneous transport of heat, liquid water, vapor, and air in partially saturated fractured porous media, with particular emphasis on strongly heat-driven flow. The presence of fractures makes the transport problem very complex, both in terms of flow geometry and physics. The numerical simulator used for our flow calculations takes into account most of the physical effects which are important in multi-phase fluid and heat flow. It has provisions to handle the extreme non-linearities which arise in phase transitions, component disappearances, and capillary discontinuities at fracture faces. We model a region around an infinite linear string of nuclear waste canisters, taking into account both the discrete fractures and the porous matrix. From an analysis of the results obtained with explicit fractures, we develop equivalent continuum models which can reproduce the temperature, saturation, and pressure variation, and gas and liquid flow rates of the discrete fracture-porous matrix calculations. The equivalent continuum approach makes use of a generalized relative permeability concept to take into account for fracture effects. This results in a substantial simplification of the flow problem which makes larger scale modeling of complicated unsaturated fractured porous systems feasible. Potential applications for regional scale simulations and limitations of the continuum approach are discussed. 27 references, 13 figures, 2 tables

  19. Decision Making under Uncertainty: A Neural Model based on Partially Observable Markov Decision Processes

    Directory of Open Access Journals (Sweden)

    Rajesh P N Rao

    2010-11-01

    Full Text Available A fundamental problem faced by animals is learning to select actions based on noisy sensory information and incomplete knowledge of the world. It has been suggested that the brain engages in Bayesian inference during perception but how such probabilistic representations are used to select actions has remained unclear. Here we propose a neural model of action selection and decision making based on the theory of partially observable Markov decision processes (POMDPs. Actions are selected based not on a single optimal estimate of state but on the posterior distribution over states (the belief state. We show how such a model provides a unified framework for explaining experimental results in decision making that involve both information gathering and overt actions. The model utilizes temporal difference (TD learning for maximizing expected reward. The resulting neural architecture posits an active role for the neocortex in belief computation while ascribing a role to the basal ganglia in belief representation, value computation, and action selection. When applied to the random dots motion discrimination task, model neurons representing belief exhibit responses similar to those of LIP neurons in primate neocortex. The appropriate threshold for switching from information gathering to overt actions emerges naturally during reward maximization. Additionally, the time course of reward prediction error in the model shares similarities with dopaminergic responses in the basal ganglia during the random dots task. For tasks with a deadline, the model learns a decision making strategy that changes with elapsed time, predicting a collapsing decision threshold consistent with some experimental studies. The model provides a new framework for understanding neural decision making and suggests an important role for interactions between the neocortex and the basal ganglia in learning the mapping between probabilistic sensory representations and actions that maximize

  20. Enhanced neuroprotective efficacy of bone marrow mesenchymal stem cells co-overexpressing BDNF and VEGF in a rat model of cardiac arrest-induced global cerebral ischemia

    Science.gov (United States)

    Zhou, Lili; Lin, Qingming; Wang, Peng; Yao, Lan; Leong, Kahong; Tan, Zhiqun; Huang, Zitong

    2017-01-01

    Cardiac arrest-induced global cerebral ischemia injury (CA-GCII) usually leads to a poor neurological outcome without an effective treatment. Bone marrow-derived mesenchymal stem cells (BMMSCs) may provide a potential cell-based therapy against neurologic disorders through induction of brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF). To optimize the neuroprotective efficacy of BMMSCs further, in this study we have derived BMMSCs, which co-overexpress both BDNF and VEGF, and tested them for the treatment of CA-GCII in a rat model. Lentiviruses that express rat BDNF exon IV or VEGF-A were created using the bicistronic shuttle vectors of pLVX-IRES-ZsGreen1 and pLVX-IRES-tdTomato, respectively. BMMSCs that were co-transduced with the engineered lentiviruses with co-overexpression of both BDNF and VEGF along with corresponding fluorescent protein reporters were injected via jugular vein of rats that just recovered from a cardiac arrest. Animals were then scored for neurofunctional deficits and examined for brain pathology and gene expression relevant to the engraftment seven days after the treatments. We demonstrate that anchorage of lentiviral vector-transduced BMMSCs, which co-overexpressed both BDNF and VEGF in the hippocampus and temporal cortex along with significantly ameliorated brain pathology and improved neurofunctional performance in CA-GCII rats after transplantation. These findings provide a proof of concept for the further validation of engineered BMMSCs for the treatment of CA-GCII patients in clinical practice in the future. PMID:28492549

  1. Implementation of geomechanical models for engineered clay barriers in multi-physic partial differential equation solvers

    International Nuclear Information System (INIS)

    Navarro, V.; Alonso, J.; Asensio, L.; Yustres, A.; Pintado, X.

    2012-01-01

    Document available in extended abstract form only. The use of numerical methods, especially the Finite Element Method (FEM), for solving boundary problems in Unsaturated Soil Mechanics has experienced significant progress. Several codes, both built mainly for research purposes and commercial software, are now available. In the last years, Multi-physic Partial Differentiation Equation Solvers (MPDES) have turned out to be an interesting proposal. In this family of solvers, the user defines the governing equations and the behaviour models, generally using a computer algebra environment. The code automatically assembles and solves the equation systems, saving the user having to redefine the structures of memory storage or to implement solver algorithms. The user can focus on the definition of the physics of the problem, while it is possible to couple virtually any physical or chemical process that can be described by a PDE. This can be done, for instance, in COMSOL Multiphysics (CM). Nonetheless, the versatility of CM is compromised by the impossibility to implement models with variables defined by implicit functions. Elasto-plastic models involve an implicit coupling among stress increments, plastic strains and plastic variables increments. For this reason, they cannot be implemented in CM in a straightforward way. This means a very relevant limitation for the use of this tool in the analysis of geomechanical boundary value problems. In this work, a strategy to overcome this problem using the multi-physics concept is presented. A mixed method is proposed, considering the constitutive stresses, the pre-consolidation pressure and the plastic variables as main unknowns of the model. Mixed methods usually present stability problems. However, the algorithmics present in CM include several numerical strategies to minimise this kind of problems. Besides, CM is based on the application of the FEM with Lagrange multipliers, an approach that significantly contributes stability

  2. A deterministic partial differential equation model for dose calculation in electron radiotherapy.

    Science.gov (United States)

    Duclous, R; Dubroca, B; Frank, M

    2010-07-07

    High-energy ionizing radiation is a prominent modality for the treatment of many cancers. The approaches to electron dose calculation can be categorized into semi-empirical models (e.g. Fermi-Eyges, convolution-superposition) and probabilistic methods (e.g.Monte Carlo). A third approach to dose calculation has only recently attracted attention in the medical physics community. This approach is based on the deterministic kinetic equations of radiative transfer. We derive a macroscopic partial differential equation model for electron transport in tissue. This model involves an angular closure in the phase space. It is exact for the free streaming and the isotropic regime. We solve it numerically by a newly developed HLLC scheme based on Berthon et al (2007 J. Sci. Comput. 31 347-89) that exactly preserves the key properties of the analytical solution on the discrete level. We discuss several test cases taken from the medical physics literature. A test case with an academic Henyey-Greenstein scattering kernel is considered. We compare our model to a benchmark discrete ordinate solution. A simplified model of electron interactions with tissue is employed to compute the dose of an electron beam in a water phantom, and a case of irradiation of the vertebral column. Here our model is compared to the PENELOPE Monte Carlo code. In the academic example, the fluences computed with the new model and a benchmark result differ by less than 1%. The depths at half maximum differ by less than 0.6%. In the two comparisons with Monte Carlo, our model gives qualitatively reasonable dose distributions. Due to the crude interaction model, these so far do not have the accuracy needed in clinical practice. However, the new model has a computational cost that is less than one-tenth of the cost of a Monte Carlo simulation. In addition, simulations can be set up in a similar way as a Monte Carlo simulation. If more detailed effects such as coupled electron-photon transport, bremsstrahlung

  3. A deterministic partial differential equation model for dose calculation in electron radiotherapy

    Science.gov (United States)

    Duclous, R.; Dubroca, B.; Frank, M.

    2010-07-01

    High-energy ionizing radiation is a prominent modality for the treatment of many cancers. The approaches to electron dose calculation can be categorized into semi-empirical models (e.g. Fermi-Eyges, convolution-superposition) and probabilistic methods (e.g. Monte Carlo). A third approach to dose calculation has only recently attracted attention in the medical physics community. This approach is based on the deterministic kinetic equations of radiative transfer. We derive a macroscopic partial differential equation model for electron transport in tissue. This model involves an angular closure in the phase space. It is exact for the free streaming and the isotropic regime. We solve it numerically by a newly developed HLLC scheme based on Berthon et al (2007 J. Sci. Comput. 31 347-89) that exactly preserves the key properties of the analytical solution on the discrete level. We discuss several test cases taken from the medical physics literature. A test case with an academic Henyey-Greenstein scattering kernel is considered. We compare our model to a benchmark discrete ordinate so