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Sample records for mechanical thrombectomy combined

  1. Mechanical thrombectomy using a combined CT/C-arm X-ray system

    PubMed Central

    Herweh, Christian; Pham, Mirko; Schönenberger, Silvia; Bösel, Julian; Ringleb, Peter A; Heiland, Sabine; Bendszus, Martin; Möhlenbruch, Markus

    2016-01-01

    Background Mechanical thrombectomy (MT) using stent-retrievers has been proven to be a safe and effective treatment in acute ischemic stroke (AIS), particularly in large vessel occlusion. Other than patient characteristics, time to recanalization is the most important factor linked to outcome. MT is usually performed in a dedicated angiography suite using a floor- and/or ceiling-mounted biplane angiographic system. Here we report our first experience of MT with a new combined CT and mobile C-arm X-ray device setup. Methods Patients with AIS underwent stroke imaging (non-contrast enhanced CT, CT perfusion, and CT angiography) using a commercially available 64-slice CT scanner which was modified for combined use with a C-arm system. In patients with large vessel occlusion, MT was conducted without further patient transfer within the CT imaging suite using a mobile C-arm X-ray device equipped with a 30×30 cm (12×12 inch), 1.5×1.5 k full-view flat detector which was positioned between the gantry and patient table. The safety and feasibility of this new system was assessed in preliminary patients. Results Angiographic imaging quality of the mobile C-arm was feasible and satisfactory for diagnostic angiography and MT. Using this setup, time between stroke imaging and groin puncture (picture-to-puncture time) was reduced by up to 35 min (including time for preparation of the patient such as intubation). Conclusions MT using a combined CT/C-arm system is safe and feasible. The potential advantages, particularly time saving and ensuing improvement in patient outcome, need to be assessed in a larger study. PMID:25935925

  2. Mechanical Thrombectomy of Hemodialysis Fistulae and Grafts

    SciTech Connect

    Patel, Aalpen A. Tuite, Catherine M.; Trerotola, Scott O.

    2005-12-15

    In this article, the authors present approaches they use in performing dialysis access intervention-in particular clotted access. It is not meant to be a comprehensive review of dialysis access management. At our institution, mechanical thrombectomy is the primary mode of treatment for clotted hemodialysis access. We will present physical examination findings in clotted dialysis access and contraindications for mechanical thrombectomy in dialysis access. We will also discuss the devices for mechanical thrombectomy and the techniques we use. Finally, we will discuss the difficulties encountered in these procedures and their solutions.

  3. Mechanical Thrombectomy of Iliocaval Thrombosis Using a Protective Expandable Sheath

    SciTech Connect

    Truong, Tri H.; Spuentrup, Elmar; Staatz, Gundula; Wildberger, Joachim E.; Schmitz-Rode, Thomas; Nolte-Ernsting, Claus C.A.; Guenther, Rolf W.; Haage, Patrick

    2004-09-15

    We report a case of successful percutaneous treatment of a subacute ilio-caval venous thrombosis in a 64-year-old female patient by using a novel combination of a rotatory fragmentation device (percutaneous thrombectomy device: PTD) and large wire basket (temporary Guenther basket filter) under temporary caval filter protection using an expandable sheath. Because the patient had multiple myeloma with increased risk for contrast media-induced renal failure, the therapeutic angiographic procedure was performed without iodinated contrast medium. Non-contrast-enhanced MR venography (high-resolution True FISP) confirmed the effective thrombus removal by the percutaneous mechanical thrombectomy procedure.

  4. Successful Recanalization of Acute Superior Mesenteric Artery Thromboembolic Occlusion by a Combination of Intraarterial Thrombolysis and Mechanical Thrombectomy with a Carotid Filter

    SciTech Connect

    Zelenak, Kamil; Sinak, Igor; Janik, Jan; Mikolajcik, Anton; Mistuna, Dusan

    2013-06-15

    Acute superior mesenteric artery (SMA) occlusion is a life-threatening disease, and acute intestinal ischemia develops from the sudden decrease in perfusion to the intestines. The key to saving the patient's life is early diagnosis, and prompt revascularization of the SMA can prevent intestinal infarction and decrease the risk of bowel segment necrosis. Computed tomographic angiography may be useful for rapid diagnosis. We report recanalization of an SMA occlusion in an 80-year-old man with a combination of intraarterial thrombolysis and mechanical thrombectomy with a carotid filter.

  5. Intracoronary thrombolytic therapy: a treatment option for failed mechanical thrombectomy.

    PubMed

    Gallagher, Sean; Jain, Ajay K; Archbold, R Andrew

    2012-11-01

    The benefit of the routine application of aspiration thrombectomy in primary percutaneous coronary intervention (PPCI) is now well established. The optimal management of patients who have "failed" thrombectomy characterized by a large residual thrombus burden after repeated mechanical thrombectomy, however, is not known. We report a case of failed aspiration thrombectomy in a 66-year-old woman who was admitted to our institution with chest pain associated with inferior ST segment elevation. Coronary angiography showed a thrombotic occlusion of the right coronary artery. Aspiration thrombectomy did little to reduce thrombus load and so the patient was treated with intracoronary tenecteplase. Repeat coronary angiography 18 hr later revealed marked thrombus resolution with thrombolysis in myocardial infarction (TIMI) grade 3 anterograde flow and patency of the infarct-related artery was maintained at 2-month follow up. This case demonstrates the potential for intracoronary thrombolytic therapy as a treatment option for the management of patients following failed thrombectomy in PPCI.

  6. Superior Mesenteric Artery Embolism Treated with Percutaneous Mechanical Thrombectomy

    SciTech Connect

    Popovic, Peter Kuhelj, Dimitrij; Bunc, Matjaz

    2011-02-15

    A case of acute superior mesenteric artery embolism treated with percutaneous thrombus aspiration is described. A 63-year-old man with chronic atrial fibrillation was admitted to the hospital with progressive abdominal pain. Computed tomography angiography revealed an occlusion of the distal part of the superior mesenteric artery. The patient was effectively treated using transaxillary percutaneous mechanical thrombectomy using a 6F Aspirex thrombectomy catheter.

  7. Influence of Thrombus Age on the Mechanical Thrombectomy Efficacy of the Amplatz Thrombectomy Device In Vitro

    SciTech Connect

    Grimm, Jan Jahnke, Thomas; Muhle, Claus; Heller, Martin; Mueller-Huelsbeck, Stefan

    2003-06-15

    Purpose: To determine the efficacy of thrombectomy for the Amplatz Thrombectomy Device (ATD) according to the age of the thrombus. Methods: Thrombectomy was performed with the 7 Fr or 8 Fr ATD. Five-day-old or 8-day-old thrombi were made from porcine blood by clotting within silicone tubes to be used in a flow model. Emboli sizes, weight, remaining thrombus and activation time were evaluated. Results: The age of the thrombus had no influence on the activation time necessary for complete thrombolysis. A significant difference was found in the overall amount of embolization only with the 7 Fr device although a similar trend was shown with the 8 Fr device. The amount of embolized thrombotic material was higher for both devices if older thrombi (i.e., 8 days old) we reprocessed. The overall impression was that the 8 Fr device showed slightly better results (less remaining thrombus and embolization). Conclusion: A tendency toward higher amounts of embolization was observed if older thrombi were used in the model. Therefore the interventional radiologist should be aware of the potentially higher risk of peripheral embolization when performing mechanical thrombectomy(with the ATD) in older thrombotic occlusions, especially since the higher rate of embolization was mainly due to an increased proportion of larger embolic particles (1 mm), which are clinically more significant.

  8. Mechanical Thrombectomy of Occluded Hemodialysis Native Fistulas and Grafts Using a Hydrodynamic Thrombectomy Catheter: Preliminary Experience

    SciTech Connect

    Sahni, Vikram Kaniyur, Sunil; Malhotra, Anmol; Fan, Stanley; Blakeney, Charles; Fotheringham, Tim; Sobeh, Mohammed; Matson, Matthew

    2005-12-15

    The purpose of this study was to evaluate the efficacy and safety of a new hydrodynamic percutaneous thrombectomy catheter in the treatment of thrombosed hemodialysis fistulas and grafts. Twenty-two patients (median age: 47 years; range: 31-79 years) underwent mechanical thrombectomy for thrombosed hemodialysis fistulas or polytetrafluoroethylene (PTFE) grafts. In all cases, an Oasis hydrodynamic catheter was used. Five patients had native fistulas and 17 had PTFE grafts. Six patients required repeat procedures. All patients with native fistulas and 15 of the 17 with PTFE grafts also underwent angioplasty of the venous limb following the thrombectomy. Major outcome measures included technical success, clinical success, primary and secondary patency, and complication rates. Twenty-eight procedures were performed in total. The technical success rate was 100% and 90% and clinical success was 86% and 76% for native fistulas and grafts, respectively. The primary patency at 6 months was 50% and 59% for fistulas and grafts, respectively, and the secondary patency at 6 months was 75% and 70% for fistulas and grafts, respectively. Two patients died of unrelated causes during the follow-up period. The Oasis catheter is an effective mechanical device for the percutaneous treatment of thrombosed hemodialysis access. Our initial success rate showed that the technique is safe in the treatment of both native fistulas and grafts.

  9. A Novel Mechanical Thrombectomy Device for Retrieval of Intravascular Thrombus

    SciTech Connect

    Monsky, Wayne L.; Finitsis, Stephanos; Cicco, Dino De; Brock, John M.; Kucharczyk, John; Latchaw, Richard E.

    2011-04-15

    Purpose: Thrombotic and embolic vascular occlusion represents a leading cause of morbidity and mortality. Currently available thrombectomy devices have limitations, including difficulty removing organized thrombus and clot fragmentation with distal embolization. A novel mechanical thrombectomy device (MTD), designed to remove both hard and soft thrombus without trauma to the blood vessel, was tested in preclinical porcine models evaluating efficacy, safety, and ease of use. Materials and Methods: A total of 26 vessels in 14 pigs underwent mechanical thrombectomy with MTD. Thrombectomy was performed in nine superficial femoral arteries, eight subclavian arteries, five primary branches of the subclavian artery, lateral thoracic artery or the thyrocervical trunk, and four external carotids. Subacute organized fibrin-laden thrombus was injected into the arteries producing vascular occlusion. The MTD was then used for thrombectomy to restore patency and blood flow. Results: Intact thrombus was retrieved from 24 of 26 of the vessels with a single pass of the MTD, resulting in complete restoration of patency in 21 vessels and partial patency in 4 vessels. In 8 cases that used an early design, the embolic material fragmented during withdrawal from the access sheath. In 4 procedures that used an early design, the MTD failed to deploy fully and the embolus was not completely captured. No intraprocedural complications or vascular damage occurred. Conclusions: The present pilot studies demonstrate basic safety and efficacy of a novel MTD with design attributes suitable for retrieval of intact acute and organized chronic thrombus. The device has potential intracranial and peripheral utility.

  10. Mechanical Solitaire Thrombectomy with Low-Dose Booster Tirofiban Injection

    PubMed Central

    Goh, Duck-Ho; Jeong, Hae Woong; Ha, Sam Yeol

    2016-01-01

    Purpose Mechanical thrombectomy using a Solitaire stent has been associated with a high recanalization rate and favorable clinical outcome in intra-arterial thrombolysis. To achieve a higher recanalization rate for mechanical Solitaire thrombectomy, we used an intra-arterial low-dose booster tirofiban injection into the occluded segment after stent deployment. We report the safety and recanalization rates for mechanical Solitaire thrombectomy with a low-dose booster tirofiban injection. Materials and Methods Between February and March 2013, 13 consecutive patients underwent mechanical Solitaire thrombectomy with low-dose booster tirofiban injection. The occlusion sites included the proximal middle cerebral artery (5 patients), the internal carotid artery (5 patients), the top of the basilar artery (2 patients) and the distal middle cerebral artery (M2 segment, 1 patient). Six patients underwent bridge treatment, including intravenous tissue plasminogen activator. Tirofiban of 250 µg was used in all patients except one (500 µg). All occluded vessels were recanalized after 3 attempts at stent retrieval (1 time, n=9; 2 times, n=2; 3 times, n=2). Results Successful recanalization was achieved in all patients (TICI 3, n=8; TICI 2b, n=5). Procedural complications developed in 3 patients (subarachnoid hemorrhage, n=2; hemorrhagic transformation, n=1). Mortality occurred in one patient with a basilar artery occlusion due to reperfusion brain swelling after mechanical Solitaire thrombectomy with low-dose booster tirofiban injection. Favorable clinical outcome (mRS≤2) was observed in 8 patients (61.5%). Conclusion Our modified mechanical Solitaire thrombectomy method using a low-dose booster tirofiban injection might enhance the recanalization rate with no additive hemorrhagic complications.

  11. Mechanical Solitaire Thrombectomy with Low-Dose Booster Tirofiban Injection

    PubMed Central

    Goh, Duck-Ho; Jeong, Hae Woong; Ha, Sam Yeol

    2016-01-01

    Purpose Mechanical thrombectomy using a Solitaire stent has been associated with a high recanalization rate and favorable clinical outcome in intra-arterial thrombolysis. To achieve a higher recanalization rate for mechanical Solitaire thrombectomy, we used an intra-arterial low-dose booster tirofiban injection into the occluded segment after stent deployment. We report the safety and recanalization rates for mechanical Solitaire thrombectomy with a low-dose booster tirofiban injection. Materials and Methods Between February and March 2013, 13 consecutive patients underwent mechanical Solitaire thrombectomy with low-dose booster tirofiban injection. The occlusion sites included the proximal middle cerebral artery (5 patients), the internal carotid artery (5 patients), the top of the basilar artery (2 patients) and the distal middle cerebral artery (M2 segment, 1 patient). Six patients underwent bridge treatment, including intravenous tissue plasminogen activator. Tirofiban of 250 µg was used in all patients except one (500 µg). All occluded vessels were recanalized after 3 attempts at stent retrieval (1 time, n=9; 2 times, n=2; 3 times, n=2). Results Successful recanalization was achieved in all patients (TICI 3, n=8; TICI 2b, n=5). Procedural complications developed in 3 patients (subarachnoid hemorrhage, n=2; hemorrhagic transformation, n=1). Mortality occurred in one patient with a basilar artery occlusion due to reperfusion brain swelling after mechanical Solitaire thrombectomy with low-dose booster tirofiban injection. Favorable clinical outcome (mRS≤2) was observed in 8 patients (61.5%). Conclusion Our modified mechanical Solitaire thrombectomy method using a low-dose booster tirofiban injection might enhance the recanalization rate with no additive hemorrhagic complications. PMID:27621948

  12. Percutaneous mechanical thrombectomy for treatment of acute femoropopliteal bypass occlusion

    PubMed Central

    Lichtenberg, Michael; Käunicke, Matthias; Hailer, Birgit

    2012-01-01

    Acute and subacute ischemia of the legs in acute and subacute femoropopliteal bypass occlusion is a dramatic situation that endangers the survival of the limbs, depending on the severity of the ischemia. Different therapy options like percutaneous mechanical thrombectomy procedures, which include rotational thrombectomy, have become available in recent years, in addition to local lysis and surgical thrombectomy. Surgical thrombectomy using the Fogarty catheter technique, in particular, shows an increased incidence of perioperative complications but only small technical success rates in randomized trials. On the other hand, local lysis is associated with increased costs due to resource-consuming measures, such as intensive monitoring and repeat angiographies, in addition to bleeding complications. In the past, further development of the Straub Rotarex® system as an endovascular therapy option has demonstrated good success leading to amputation-free survival in multiple studies. At the same time, a low rate of complications with use has been documented. Most examinations have been conducted in the thigh. To date, there are little investigational data on its use in acutely and subacutely occluded femoropopliteal bypasses. In this paper, the current study-based significance of the Rotarex system for this indication is analyzed based on the existing literature and the authors’ own experiences with 22 patients. PMID:22661895

  13. Stroke and cardiac papillary fibroelastoma: mechanical thrombectomy after thrombolytic therapy.

    PubMed

    Santos, Ana F; Pinho, João; Ramos, Vítor; Pardal, Joana; Rocha, Jaime; Ferreira, Carla

    2014-01-01

    We describe a case of a 34-year-old man with a sudden development of right hemiparesis and aphasia because of infarction of the left middle cerebral artery that was submitted to intravenous (IV) recombinant tissue plasminogen activator and mechanical thrombectomy. Transesophageal echocardiogram showed a small mass on the anterior leaflet of the mitral valve. Cardiac surgery was performed, and histological examination of the removed material was consistent with cardiac papillary fibroelastoma (CPF). Experience in using IV thrombolysis for the treatment of embolic stroke because of CPF is limited. To the best of our knowledge, only 3 patients are reported in literature in whom acute ischemic stroke and associated CPF were treated with thrombolytic therapy. A discussion of the efficacy of IV thrombolysis and the possible superiority of mechanical thrombectomy is included.

  14. Mechanical Thrombectomy in Patients with Deep Venous Thrombosis

    SciTech Connect

    Delomez, Maxence; Beregi, Jean-Paul; Willoteaux, Serge; Bauchart, Jean-Jacques; D'Othee, Bertrand Janne; Asseman, Philippe; Perez, Nessim; Thery, Claude

    2001-01-15

    Purpose: To report our experience with mechanical thrombectomy in proximal deep vein thrombosis (DVT).Methods: Eighteen patients with a mean ({+-} SD) age of 37.6 {+-} 16.1 years who presented with DVT in the iliac and femoral vein (n = 3), inferior vena cava (n = 5), or inferior vena cava and iliac vein (n = 10), were treated with the Amplatz Thrombectomy Device after insertion of a temporary caval filter.Results: Successful recanalization was achieved in 15 of 18 patients (83%). Overall, the percentage of thrombus removed was 66 {+-} 29%: 73 {+-} 30% at caval level and 55 {+-} 36% at iliofemoral level. Complementary interventions (seven patients) were balloon angioplasty (n = 2), angioplasty and stenting (n = 2), thrombo-aspiration alone (n = 1), thrombo-aspiration, balloon angioplasty, and permanent filter (n = 1), and permanent filter alone (n = 1). There was one in-hospital death. Follow-up was obtained at a mean of 29.6 months; three patients had died (two cancers, one myocardial infarction); 10 had no or minimal sequelae; one had post-phlebitic limb.Conclusion: Mechanical thrombectomy is a potential therapeutic option in patients presenting with proximal DVT.

  15. New Cerebral Microbleeds After Mechanical Thrombectomy for Large-Vessel Occlusion Strokes

    PubMed Central

    Shi, Zhong-Song; Duckwiler, Gary R.; Jahan, Reza; Tateshima, Satoshi; Gonzalez, Nestor R.; Szeder, Viktor; Saver, Jeffrey L.; Kim, Doojin; Ali, Latisha K.; Starkman, Sidney; Vespa, Paul M.; Salamon, Noriko; Villablanca, J. Pablo; Viñuela, Fernando; Feng, Lei; Loh, Yince; Liebeskind, David S.

    2015-01-01

    Abstract The interval appearance of cerebral microbleeds (CMBs) after endovascular treatment has never been described. We investigated the frequency and predictors of new CMBs that developed shortly after mechanical thrombectomy for acute ischemic stroke, and its impact on clinical outcome. We retrospectively analyzed patients with large-vessel occlusion strokes treated with Merci Retriever, Penumbra System, or stent-retriever devices. Serial T2∗-weighted gradient-recall echo (GRE) magnetic resonance imaging (MRI) before and 48 h after endovascular thrombectomy were assessed to identify new CMBs. We examined independent factors associated with new CMBs after mechanical thrombectomy. We analyzed the association of the presence, burden, and distribution of new CMBs with clinical outcome. A total of 187 consecutive patients with serial GRE were enrolled in this study. CMBs were evident in 36 (19.3%) patients before mechanical thrombectomy. New CMBs occurred in 41 (21.9%) patients after mechanical thrombectomy. Of the 68 new CMBs, 45 appeared in the lobar location, 18 in the deep location and 5 in the infratentorial location. The presence of baseline CMBs was associated with new CMBs after mechanical thrombectomy (OR 5.38; 95% CI 2.13–13.59; P < 0.001), no matter whether the patients were treated primarily with mechanical thrombectomy or with intravenous thrombolysis followed by mechanical thrombectomy. Patients with new CMBs did not have increased rates of hemorrhagic transformation, in-hospital mortality, and modified Rankin Scale score 4 to 6 at discharge. New CMBs are common after mechanical thrombectomy in one-fifth of patients with acute ischemic stroke. Baseline CMBs before mechanical thrombectomy predicts the development of new CMBs. New CMBs after mechanical thrombectomy do not influence clinical outcome. PMID:26632753

  16. Current status of mechanical thrombectomy for acute stroke treatment.

    PubMed

    Pereira, Vitor Mendes; Yilmaz, Hasan; Pellaton, Alain; Slater, Lee-Anne; Krings, Timo; Lovblad, Karl-Olof

    2015-02-01

    Acute ischemic stroke is a morbid and disabling medical condition with a significant social and economic impact throughout the world. Intravenous thrombolysis (IVT) has been the first line treatment for patients presenting up to 4.5 hours after symptom onset for many years. Endovascular stroke treatment has been used successfully as rescue therapy after failed IVT; in patients with contraindications to rtPA or presenting outside the 4.5-hour window. The effectiveness of IVT is high for distal thrombi but significantly lower for proximal occlusions. Endovascular treatment has been revolutionized by the evolution from intra-arterial thrombolysis and first generation mechanical devices to the current generation of stent retrievers and aspiration systems with large bore catheters. These devices have been associated with excellent revascularization, improved clinical outcomes, shorter procedure times and reduced device and procedure related complications. We report the current literature, clinical standards and perspectives on mechanical thrombectomy in acute ischemic stroke.

  17. Primary stentriever versus combined stentriever plus aspiration thrombectomy approaches: in vitro stroke model comparison

    PubMed Central

    Mokin, Maxim; Ionita, Ciprian N; Nagesh, Swetadri Vasan Setlur; Rudin, Stephen; Levy, Elad I; Siddiqui, Adnan H

    2014-01-01

    Background Artificial stroke models can be used for testing various thrombectomy devices. Objective To determine the value of combined stentriever–aspiration thrombectomy compared with the stentriever-alone approach. Methods We designed an in vitro model of the intracranial circulation with a focus on the middle cerebral artery (MCA) that closely resembles the human intracranial circulation. After introducing fresh clot in the MCA, we used conventional biplane angiography and microangiographic fluoroscopy to compare recanalization rates and occurrence of emboli in new, unaffected territory for thrombectomy approaches in which a stentriever (Solitaire flow restoration stentriever, Covidien) was used alone or in combination with continuous manual aspiration through a Navien catheter (Covidien). Results In a total of 22 experiments (11 for each approach), successful clot delivery to the MCA was achieved in all cases. Successful angiographic recanalization (thrombolysis in cerebral infarction score of 2b–3) was achieved more frequently with the combined stentriever–aspiration approach than with the stentriever-alone approach (in 10 vs 4 experiments, p=0.023). Emboli in new territory occurred in three experiments with the stentriever-alone approach, and none were seen with the combined approach (p=0.21). Conclusions The combined stentriever–aspiration approach to thrombectomy leads to better angiographic recanalization rates than use of the stentriever alone. Further experiments are needed to test the value of balloon-guide catheters and aspiration performed using other types of catheters and modes of aspiration. PMID:24789594

  18. Mechanical thrombectomy in cardiac myxoma stroke: a case report and review of the literature.

    PubMed

    Chung, Yoon Sang; Lee, Woong Jae; Hong, Joonhwa; Byun, Jun Soo; Kim, Jae Kyun; Chae, Soo Ahn

    2016-06-01

    Cardiac myxoma is the most common primary tumor of the heart. It is a rare cause of acute ischemic stroke and commonly not detected until after the stroke. There is no current guideline for the treatment of cardiac myxoma stroke and only a few cases of mechanical thrombectomy have been reported. We present a case of cardiac myxoma stroke in a 4-year-old boy treated with a stent-retrieval device and review the literature describing the safety and efficacy of mechanical thrombectomy in cardiac myxoma stroke. We also describe imaging features of the myxoma clot on susceptibility weighted images. PMID:27040551

  19. Adjuvant Tirofiban Injection Through Deployed Solitaire Stent As a Rescue Technique After failed Mechanical Thrombectomy in Acute Stroke

    PubMed Central

    Seo, Jung Hwa; Kim, Sung Tae; Kim, Eun-Gyu

    2015-01-01

    Purpose We present our experiences of intra-arterial tirofiban injection through a deployed Solitaire stent as a rescue therapy after failed mechanical thrombectomy in patients with acute ischemic stroke. Materials and Methods Data on 18 patients treated with adjunctive tirofiban injection through a temporarily deployed Solitaire stent after failed mechanical thrombectomy were retrospectively reviewed. Solitaire stent was used as a primary thrombectomy device in 16 of 18 patients. Two patients received manual aspiration thrombectomy initially. If initial mechanical thrombectomy failed, tirofiban was injected intra-arterially through the deployed Solitaire stent and then subsequent Solitaire thrombectomy was performed. Results Fourteen patients had occlusions in the middle cerebral artery, 2 in the distal internal carotid artery, and 2 in the basilar artery. Successful recanalization was achieved in 14 patients (77.7%) after intra-arterial injection of tirofiban and subsequent Solitaire thrombectomy. Three patients without successful recanalization after rescue method received angioplasty with stenting. Overall, successful recanalization (TICI grades 2b and 3) was achieved in 17 (94.4%) of 18 patients. Periprocedural complications occurred in 5 patients: distal migration of emboli in 5 patients and vessel perforation in 1. Three patients died. Good functional outcome (mRS ≤ 2) was achieved in 9 patients (50.0%) at 3 months. Conclusion Rescue intra-arterial injection of tirofiban through a temporarily deployed Solitaire stent may facilitate further recanalization in cases of failed mechanical thrombectomy in patients with acute ischemic stroke. PMID:25763294

  20. Developments in mechanical thrombectomy devices for the treatment of acute ischemic stroke.

    PubMed

    Mordasini, Pasquale; Gralla, Jan

    2016-01-01

    Several recent prospective randomized controlled trials of endovascular stroke therapy using latest generation thrombectomy devices, so called stent-retrievers, have shown significantly improved clinical outcome compared to the standard treatment with intra-venous thrombolysis using r-tPA alone. Despite some differences in inclusion criteria between these studies, all required non-invasive vessel imaging to proof occlusion of a major brain supplying vessel. Furthermore, in most studies additional imaging techniques were used to exclude patients with already established large cerebral infarction or unfavorable collateral or penumbral status. Patients with small infarct volume, severe neurological deficits and in whom thrombectomy can be initiated within the first 6 hours after symptom onset seem to benefit the most. Therefore, mechanical thrombectomy using stent-retrievers in addition to intra-venous thrombolysis is recommended for the treatment of acute ischemic stroke with proven major vessel occlusion in the anterior circulation.

  1. “Missing clot” during mechanical thrombectomy in acute stroke using Solitaire stent retrieval system

    PubMed Central

    Huded, Vikram; Nambiar, Vivek; De Souza, Romnesh; Bohra, Vikram; Ramankutty, Ritesh

    2016-01-01

    Stent retrieval system is an established treatment modality in acute ischemic stroke with large vessel occlusion. Here, we describe a complication which occurred during mechanical thrombectomy in three cases where the clot dislodged during retrieval. There was a possibility of the clot getting reinjected into the artery with possible dire consequences. PMID:27293350

  2. Mechanical Thrombectomy in Patients With Acute Ischemic Stroke: A Health Technology Assessment

    PubMed Central

    2016-01-01

    Background In Ontario, current treatment for eligible patients who have an acute ischemic stroke is intravenous thrombolysis (IVT). However, there are some limitations and contraindications to IVT, and outcomes may not be favourable for patients with stroke caused by a proximal intracranial occlusion. An alternative is mechanical thrombectomy with newer devices, and a number of recent studies have suggested that this treatment is more effective for improving functional independence and clinical outcomes. The objective of this health technology assessment was to evaluate the clinical effectiveness and cost-effectiveness of new-generation mechanical thrombectomy devices (with or without IVT) compared to IVT alone (if eligible) in patients with acute ischemic stroke. Methods We conducted a systematic review of the literature, limited to randomized controlled trials that examined the effectiveness of mechanical thrombectomy using stent retrievers and thromboaspiration devices for patients with acute ischemic stroke. We assessed the quality of the evidence using the GRADE approach. We developed a Markov decision-analytic model to assess the cost-effectiveness of mechanical thrombectomy (with or without IVT) versus IVT alone (if eligible), calculated incremental cost-effectiveness ratios using a 5-year time horizon, and conducted sensitivity analyses to examine the robustness of the estimates. Results There was a substantial, statistically significant difference in rate of functional independence (GRADE: high quality) between those who received mechanical thrombectomy (with or without IVT) and IVT alone (odds ratio [OR] 2.39, 95% confidence interval [CI] 1.88–3.04). We did not observe a difference in mortality (GRADE: moderate quality) (OR 0.80, 95% CI 0.60–1.07) or symptomatic intracerebral hemorrhage (GRADE: moderate quality) (OR 1.11, 95% CI 0.66–1.87). In the base-case cost-utility analysis, which had a 5 year time horizon, the costs and effectiveness for

  3. Intraarterial mechanical thrombectomy for the treatment of postoperative cerebral infarction: a case report

    PubMed Central

    Yun, Jong-Won; Kim, Yong-Ho; Min, Jinhye; Choi, Young Soon; Chae, Young Keun; Lee, Eun Sang; Kang, Yoo

    2014-01-01

    Perioperative ischemic stroke is an uncommon event associated with significant morbidity and mortality. The complexity of the surgical procedure and surgery induced hypercoagulable status also influence the incidence of stroke. The management of stroke involves a decision regarding the quickest suitable revascularization method. Endovascular mechanical thrombectomy, such as intra-arterial mechanical thrombectomy (IAMT), can restore vascular patency of the vessels, providing an alternative or synergistic method to restore blood flow. Although, there are no recommended treatment guidelines, IAMT is eligible to be a treatment of choice for perioperative ischemic stroke. We experienced a case of a patient who demonstrated hemiplegia and aphasia, the early symptom of acute ischemic stroke, in the post-anesthesia care unit and performed IAMT successfully. Thus we report the case with a review of the relevant literature. PMID:24910735

  4. Mechanical thrombectomy alone’ as a definite therapy for rescue angioplasty

    PubMed Central

    Jamil, Gohar; Ouda, Husam; Jamil, Mujgan; Qureshi, Anwer

    2013-01-01

    Coronary reperfusion strategies for acute ST segment elevation myocardial infarction (STEMI) include primary percutaneous coronary intervention (PCI), intravenous thrombolytic agents and recently mechanical thrombectomy alone during PCI, the latter reserved for those without significant residual disease post-thrombectomy. We describe the success of ‘mechanical thrombectomy alone’ in two young patients undergoing rescue angioplasty at our institution. Both patients were thrombolysed for inferior STEMI. During rescue PCI, post-thrombus aspiration, mild underlying atherosclerotic burden was detected in both patients, thus possibly obviating the need for further balloon angioplasty or stenting. Cost and compliance with long-term dual antiplatelet therapy (DAPT) was an additional factor to avoid stenting. Both patients received aspirin, clopidogrel, heparin and additional standard therapy for myocardial infarction (MI). Medication compliance was ensured by providing 1 month DAPT at no extra cost. Short-term follow-up at 1 and 3 months, for both patients was uneventful. Two-year, long-term follow-up, available for one patient has been uneventful. PMID:23513023

  5. Treatment of the Superior Sagittal Sinus Thrombosis with the Mechanical Thrombectomy Using Stent-Retriever Device.

    PubMed

    Kim, Hoon; Kim, Seong Rim; Park, Ik Seong; Kim, Young Woo

    2016-09-01

    Cerebral venous sinus thrombosisis an uncommon entity and its clinical presentations are highly variable. We present the case of superior sagittal sinus thrombosis. Although it was medical refractory, successfully treated with mechanical thrombectomy using the Solitaire FR device. A 27-year-old man who presented with venous infarction accompanied by petechial hemorrhage secondary to the superior sagittal sinus (SSS) thrombosis. Due to rapid deterioration despite of anticoagulation therapy, the patient was taken for endovascular treatment. We deployed the Solitaire FR device (4×20 mm) in the anterior portion of the thrombosed SSS, and it was left for ten minutes before the retraction. Thus, we removed a small amount of thrombus. But the sinus remained occluded. We therefore performed the thrombectomy using the same methods using the Solitaire FR (6×20 mm). Thus, we were successful in removing larger clots. Our case highlights not only that the mechanical thrombectomy using the Solitaire FR is effective in achieving revascularization both rapidly and efficiently available, but also that it might be another option in patients with cerebral venous sinus thrombosis who concurrently had rapid clinical deterioration with devastating consequences.

  6. Treatment of the Superior Sagittal Sinus Thrombosis with the Mechanical Thrombectomy Using Stent-Retriever Device

    PubMed Central

    Kim, Hoon; Kim, Seong Rim; Park, Ik Seong

    2016-01-01

    Cerebral venous sinus thrombosisis an uncommon entity and its clinical presentations are highly variable. We present the case of superior sagittal sinus thrombosis. Although it was medical refractory, successfully treated with mechanical thrombectomy using the Solitaire FR device. A 27-year-old man who presented with venous infarction accompanied by petechial hemorrhage secondary to the superior sagittal sinus (SSS) thrombosis. Due to rapid deterioration despite of anticoagulation therapy, the patient was taken for endovascular treatment. We deployed the Solitaire FR device (4×20 mm) in the anterior portion of the thrombosed SSS, and it was left for ten minutes before the retraction. Thus, we removed a small amount of thrombus. But the sinus remained occluded. We therefore performed the thrombectomy using the same methods using the Solitaire FR (6×20 mm). Thus, we were successful in removing larger clots. Our case highlights not only that the mechanical thrombectomy using the Solitaire FR is effective in achieving revascularization both rapidly and efficiently available, but also that it might be another option in patients with cerebral venous sinus thrombosis who concurrently had rapid clinical deterioration with devastating consequences. PMID:27651872

  7. Treatment of the Superior Sagittal Sinus Thrombosis with the Mechanical Thrombectomy Using Stent-Retriever Device

    PubMed Central

    Kim, Hoon; Kim, Seong Rim; Park, Ik Seong

    2016-01-01

    Cerebral venous sinus thrombosisis an uncommon entity and its clinical presentations are highly variable. We present the case of superior sagittal sinus thrombosis. Although it was medical refractory, successfully treated with mechanical thrombectomy using the Solitaire FR device. A 27-year-old man who presented with venous infarction accompanied by petechial hemorrhage secondary to the superior sagittal sinus (SSS) thrombosis. Due to rapid deterioration despite of anticoagulation therapy, the patient was taken for endovascular treatment. We deployed the Solitaire FR device (4×20 mm) in the anterior portion of the thrombosed SSS, and it was left for ten minutes before the retraction. Thus, we removed a small amount of thrombus. But the sinus remained occluded. We therefore performed the thrombectomy using the same methods using the Solitaire FR (6×20 mm). Thus, we were successful in removing larger clots. Our case highlights not only that the mechanical thrombectomy using the Solitaire FR is effective in achieving revascularization both rapidly and efficiently available, but also that it might be another option in patients with cerebral venous sinus thrombosis who concurrently had rapid clinical deterioration with devastating consequences.

  8. Treatment of the Superior Sagittal Sinus Thrombosis with the Mechanical Thrombectomy Using Stent-Retriever Device.

    PubMed

    Kim, Hoon; Kim, Seong Rim; Park, Ik Seong; Kim, Young Woo

    2016-09-01

    Cerebral venous sinus thrombosisis an uncommon entity and its clinical presentations are highly variable. We present the case of superior sagittal sinus thrombosis. Although it was medical refractory, successfully treated with mechanical thrombectomy using the Solitaire FR device. A 27-year-old man who presented with venous infarction accompanied by petechial hemorrhage secondary to the superior sagittal sinus (SSS) thrombosis. Due to rapid deterioration despite of anticoagulation therapy, the patient was taken for endovascular treatment. We deployed the Solitaire FR device (4×20 mm) in the anterior portion of the thrombosed SSS, and it was left for ten minutes before the retraction. Thus, we removed a small amount of thrombus. But the sinus remained occluded. We therefore performed the thrombectomy using the same methods using the Solitaire FR (6×20 mm). Thus, we were successful in removing larger clots. Our case highlights not only that the mechanical thrombectomy using the Solitaire FR is effective in achieving revascularization both rapidly and efficiently available, but also that it might be another option in patients with cerebral venous sinus thrombosis who concurrently had rapid clinical deterioration with devastating consequences. PMID:27651872

  9. Mechanical Thrombectomy of Iliac Vein Thrombosis in a Pig Model Using the Rotarex and Aspirex Catheters

    SciTech Connect

    Minko, P. Bücker, A.

    2013-06-08

    PurposeTo investigate the efficacy and safety of mechanical thrombectomy for iliac vein thrombosis using Rotarex and Aspirex catheters in a pig model.Materials and MethodsIliac vein thrombosis was induced in six pigs by means of an occlusion-balloon catheter and thrombin injection. The presence of thrombi was verified by digital subtraction angiography (DSA) and computed tomography (CT). Thrombectomy was performed using 6F and 8F Rotarex and 6F, 8F, and 10F Aspirex catheters (Straub Medical AG, Wangs, Switzerland). After intervention, DSA and CT were repeated to evaluate the efficacy of mechanical thrombectomy and to exclude local complications. In addition, pulmonary CT was performed to rule out pulmonary embolism. Finally, all pigs were killed, and iliac veins were dissected to perform macroscopic and histological examination.ResultsThrombus induction was successfully achieved in all animals as verified by DSA and CT. Subsequent thrombectomy lead to incomplete recanalization of the iliac veins with residual thrombi in all cases. However, the use of the 6F and 8F Rotarex catheters caused vessel perforation and retroperitoneal hemorrhage in all cases. Application of the Aspirex device caused one small transmural perforation in a vessel treated with a 10F Aspirex catheter, and this was only seen microscopically. Pulmonary embolism was detected in one animal treated with the Rotarex catheters, whereas no pulmonary emboli were seen in animals treated with the Aspirex catheters.ConclusionThe Aspirex catheter allowed subtotal and safe recanalization of iliac vein thrombosis. In contrast, the use of the Rotarex catheter caused macroscopically obvious vessel perforations in all cases.

  10. Mechanical thrombectomy for acute ischemic stroke in pregnancy using the penumbra system.

    PubMed

    Aaron, Sanjith; Shyamkumar, N K; Alexander, Sunithi; Babu, P Suresh; Prabhakar, A T; Moses, Vinu; Murthy, T V; Alexander, Mathew

    2016-01-01

    Even though intravenous thrombolysis with tissue plasminogen activator (IV tPA) is the standard of care in acute ischemic stroke, its use in pregnancy is not clearly defined. Mechanical thrombectomy devices can be an option; however, literature on the use of such mechanical devices in stroke in pregnancy is lacking. Here we describe two cases that developed acute embolic stroke during pregnancy who were successfully treated by mechanical clot retrieval using the Penumbra system 28 (Penumbra Inc., Alameda, California, USA). To the best of our knowledge, these are the only case reports on the use of the Penumbra device in pregnant patients with acute ischemic stroke. PMID:27293343

  11. Revascularization of a thrombosed, previously stented aorto-renal graft using combined directional atherectomy and AngioJet thrombectomy.

    PubMed

    Seth, A; Mathur, A; Chandra, P; Aggarwal, P; Khanna, N

    1999-01-01

    We report an interesting case with bilateral PTFE aorto-renal grafts of which one graft underwent balloon angioplasty and stenting for proximal stenosis. Combined debulking by AngioJet thrombectomy and Simpsons directional atherectomy was performed within the stent following reocclusion of the graft 9 months later. PMID:10348574

  12. Efficacy and Safety of Thrombectomy Combined with Intracoronary Administration of Tirofiban in ST-segment Elevation Myocardial Infarction (STEMI)

    PubMed Central

    Gao, Lu; Cao, Zhenhua; Zhang, Hong

    2016-01-01

    Background No/slow reflow gives rise to serious complications in STEMI patients undergoing PCI, and can lead to worse outcomes. Several measures are used to prevent no/slow reflow, including thrombus removal processes and intensive use of anticoagulant agents. Our study was designed to evaluate the efficacy and safety of thrombectomy and intracoronary administration of GPIIb/IIIa inhibitors in STEMI patients undergoing PPCI. Material/Methods We randomly assigned 240 STEMI patients into 3 groups. Before PPCI, patients in group A received thrombectomy and intracoronary administration of tirofiban. Patients in group B received thrombectomy, and patients in group C neither of these 2 treatments. Their demographic data and coronary angiography results were recorded. TIMI grade flow was used to evaluate the effect. After the follow-up, major adverse cardiac events were regarded as study endpoints in evaluating the safety of the combined therapy. Results We found no significant differences among the 3 groups in demographic and clinical characteristics (p>0.05). Patients in group A had better TIMI grade classifications and ST-segment elevation (p=0.005), and lower incidence of no/slow reflow (p=0.031) and MACE. During 6-month follow-up, the MACE rate was lower in group A than in groups B and C (p=0.038). Conclusions The use of thrombectomy combined with intracoronary administration of tirofiban is relatively effective and safe in STEMI patients undergoing PPCI. PMID:27475844

  13. Emergent extracranial internal carotid artery stenting and mechanical thrombectomy in acute ischaemic stroke

    PubMed Central

    Mishra, Ankit; Stockley, Hannah; Goddard, Tony; Sonwalker, Hemant; Wuppalapati, Siddhartha

    2015-01-01

    Objective Tandem occlusions involving both the extracranial internal carotid artery (ICA) and an intracranial artery typically respond poorly to intravenous (IV) tissue plasminogen activator (t-PA). We retrospectively review our experience with proximal ICA stenting and stent-assisted thrombectomy of the distal artery. Methods The data included patients that underwent carotid stenting and mechanical thrombectomy between 2012–2013. Radiographic, clinical, and procedural data were drawn from case notes, imaging records and discharge reports. Clinical outcomes were evaluated using the National Institutes of Health Stroke Scale (NIHSS) and the modified Rankin scale (mRs). Results Seven patients, with a mean age of 66.4 years and a mean admission NIHSS of 18.3, underwent this procedure and were included. Each presented with an occlusion of the proximal ICA, with additional occlusions of the ICA terminus (n = 3), middle cerebral artery (n = 5), or anterior cerebral artery (n = 1). Recanalisation of all identified occlusions was achieved in all patients, with a Thrombolysis in Myocardial Infarction (TIMI) score of 3 and a Thrombolysis in Cerebral Infarction (TICI) score >2b achieved in each case. Mean time from onset of stroke symptoms to recanalisation was 287 min; mean time from first angiography to recanalisation was 52 min. Intracranial haemorrhages occurred in two patients, with no increase in NIHSS. There were no mortalities. Mean NIHSS at discharge was 4.9, and mRs at 90 days was one in all patients. Conclusions Treatment of tandem extracranial ICA and intracranial occlusions in the setting of acute ischaemic stroke with extracranial carotid artery stenting followed by adjunctive intracranial mechanical thrombectomy is both safe and effective, but further evaluation of this treatment modality is necessary. PMID:25943850

  14. Effective mechanical thrombectomy in a patient with hyperacute ischemic stroke associated with cardiac myxoma.

    PubMed

    Baek, Seol-Hee; Park, Soonchan; Lee, Nam Joon; Kang, Youngjin; Cho, Kyung-Hee

    2014-10-01

    Ischemic stroke is the most common neurologic manifestation of cardiac myxoma. However, there has been no current guideline on the treatment of hyperacute ischemic stroke due to cardiac myxoma. We describe a patient with hyperacute stroke caused by cardiac myxoma who had a good outcome with rapid recanalization through mechanical thrombectomy. A 46-year-old man was admitted with acute symptoms of right side hemiplegia and global aphasia. Brain computed tomography (CT) angiography showed a T occlusion of the left internal carotid artery. Intravenous recombinant tissue plasminogen activator was administered. However, his clinical symptoms did not improve. Thus, we performed endovascular treatment and had a successful outcome. A pathologic examination of the retrieved clot revealed a tumor emboli from a cardiac myxoma. Transthoracic echocardiogram revealed a left atrial myxoma in which a large mass was attached to the posterior wall of the aorta. The patient's neurologic deficits recovered with the exception of left eye blindness. Reperfusion therapy with mechanical thrombectomy might be safe and effective for the rapid revascularization of large vessel occlusions in hyperacute ischemic stroke, from which the tumor thrombi can be retrieved. PMID:25174564

  15. [Successful Treatment of Repeated Bilateral Middle Cerebral Artery Occlusion by Performing Mechanical Thrombectomy in a Patient with Trousseau Syndrome].

    PubMed

    Inoue, Satoshi; Fujita, Atsushi; Mizowaki, Takashi; Uchihashi, Yoshito; Kuroda, Ryuichi; Urui, Seishirou; Kurihara, Eiji; Kohmura, Eiji

    2016-06-01

    We report a patient with Trousseau syndrome who presented with repeated acute middle cerebral artery (MCA) occlusion, which was successfully treated by performing mechanical thrombectomy. A 66-year-old man with a lung lesion and abdominal lymph node swelling experienced a sudden onset of left hemiparesis. Magnetic resonance angiography (MRA) revealed a right MCA occlusion. Perfusion-weighted imaging revealed reduced cerebral blood flow in the right MCA territory. Complete recanalization of the occluded vessel was achieved by performing mechanical thrombectomy, and his symptoms remarkably disappeared. Twenty days after the procedure, he experienced right hemiparesis and total aphasia. MRA revealed a left MCA occlusion, which was located on the contralateral side of the first occlusion. The second mechanical thrombectomy was successfully performed, and complete recanalization was successfully achieved. Right hemiparesis improved after the procedure. Histological examination of the retrieved clots revealed coagulated fibrin and platelets. Cytodiagnosis of pleural effusion revealed adenocarcinoma, and he was diagnosed with lung adenocarcinoma and cancerous pleurisy. Trousseau syndrome was the presumed primary cause of the patient's tendency for thrombogenesis. To the best of our knowledge, there were no reports regarding the repeated use of mechanical thrombectomy for patients with bilateral MCA occlusion caused by Trousseau syndrome. Neuroendovascular therapy can offer good neurological outcomes even in patients with malignant lesions. PMID:27270149

  16. Transjugular Intrahepatic Portosystemic Shunt, Mechanical Aspiration Thrombectomy, and Direct Thrombolysis in the Treatment of Acute Portal and Superior Mesenteric Vein Thrombosis

    SciTech Connect

    Ferro, Carlo; Rossi, Umberto G. Bovio, Giulio; Dahamane, M'Hamed; Centanaro, Monica

    2007-09-15

    A patient was admitted because of severe abdominal pain, anorexia, and intestinal bleeding. Contrast-enhanced multidetector computed tomography demonstrated acute portal and superior mesenteric vein thrombosis (PSMVT). The patient was treated percutaneously with transjugular intrahepatic portosystemic shunt (TIPS), mechanical aspiration thrombectomy, and direct thrombolysis, and 1 week after the procedure, complete patency of the portal and superior mesenteric veins was demonstrated. TIPS, mechanical aspiration thrombectomy, and direct thrombolysis together are promising endovascular techniques for the treatment of symptomatic acute PSMVT.

  17. Single-Center Experience Using AngioVac with Extracorporeal Bypass for Mechanical Thrombectomy of Atrial and Central Vein Thrombi.

    PubMed

    Resnick, Scott A; O'Brien, Dan; Strain, David; Malaisrie, Chris; Schimmel, Daniel; Salem, Riad; Vogelzang, Robert

    2016-05-01

    The AngioVac device (AngioDynamics, Inc, Queensbury, New York), a commercially available large-diameter aspiration cannula using extracorporeal venovenous bypass, is designed to facilitate en bloc mechanical thrombectomy of massive thrombi of the central vasculature. Between February 2014 and January 2015, seven consecutive patients, each presenting with large central thrombi of the iliac veins, vena cava, right atrium, or pulmonary artery, underwent thrombectomy. Partial or complete clot abatement was achieved in all instances. All patients survived the procedure. One case was complicated by embolization of septic thrombi. At most recent follow-up, one patient had died of causes unrelated to venous thrombosis; all other patients were living (median follow-up time 8 mo). Several technical and therapeutic insights were gained from our center's early experience.

  18. Angiographic and Clinical Factors Related with Good Functional Outcome after Mechanical Thrombectomy in Acute Cerebral Artery Occlusion

    PubMed Central

    Park, Jong Hyuk; Han, Young Min; Jang, Kyeong Sool; Yoon, Wan Soo; Jang, Dong Kyu

    2015-01-01

    Objective The aim of this study is to investigate good prognostic factors for an acute occlusion of a major cerebral artery using mechanical thrombectomy. Methods Between January 2013 to December 2014, 37 consecutive patients with acute occlusion of a major cerebral artery treated by mechanical thrombectomy with stent retrievers were conducted. We analyzed clinical and angiographic factors retrospectively. The collateral flow and the result of recanalization were sorted by grading systems. Outcome was assessed by National Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS) at 90 days. We compared the various parameters between good and poor angiographic and clinical results. Results Twenty seven patients demonstrated good recanalization [Thrombolysis in Cerebral Infarction (TICI) 2b or 3] after thrombectomy. At the 90-day follow up, 19 patients had good (mRS, 0-2), 14 had moderate (3-4) and four had poor outcomes (5-6). The mRS of older patients (≥75 years) were poor than younger patients. Early recanalization, high Thrombolysis in Myocardial Infarction risk score, and low baseline NIHSS were closely related to 90-day mRS, whereas high TICI was related to both mRS and the decrease in the NIHSS. Conclusion NIHSS decreased markedly only when recanalization was successful. A good mRS was related to low initial NIHSS, good collateral, and early successful recanalization. PMID:26539260

  19. Endovascular mechanical thrombectomy in basilar artery occlusion: variables affecting recanalization and outcome.

    PubMed

    Gilberti, Nicola; Gamba, Massimo; Premi, Enrico; Costa, Angelo; Vergani, Veronica; Delrio, Ilenia; Spezi, Raffaella; Mardighian, Dikran; Frigerio, Michele; Gasparotti, Roberto; Padovani, Alessandro; Magoni, Mauro

    2016-04-01

    Ischemic stroke due to basilar artery occlusion (BAO) is frequently associated with a poor prognosis. To date the most effective therapeutic approach has not been established and little is known about the predictors of clinical outcome. The aim of this study was to describe safety and efficacy of intra-arterial mechanical thrombectomy (IAMT) through latest generation devices in patients with BAO, focusing on those variables that may affect recanalization and clinical outcome. We analyzed retrospectively a series of 32 patients with BAO who underwent IAMT. We assessed the association of some clinical and neuroradiological features with recanalization rate and clinical outcome. Successful recanalization was achieved in 28 out of 32 patients (87.5 %). Symptomatic intracerebral hemorrhage (SICH) was observed in 2/32 patients (6.3 %) and mortality in the first 3 months was 25.0 %. At 3-month follow up evaluation, 13/32 patients (40.6 %) showed a good functional outcome (mRS score ≤2). There were no statistical differences in term of age, gender, risk factors, cause of stroke, recanalization rate, pre-treatment pc-ASPECTS score and SICH frequencies between patients with favorable and unfavorable outcome. Increased length of thrombi was associated with unfavorable clinical outcome at 3 months. Recanalization rate was not affected by any of the variables considered. In BAO, IAMT through newest generation devices has high recanalization rates and low complication frequencies. Length of BAO is an important predictor of clinical outcome.

  20. The use of mechanical thrombectomy in the treatment of basilar artery occlusion--case report.

    PubMed

    Knap, Daniel; Honkowicz, Maciej; Kirmes, Tomasz; Koroński, Marcin; Kysiak, Marzena; Bukański, Mateusz; Sieroń, Dominik; Dymon, Izabela; Baron, Jan

    2015-01-01

    Occlusion of the basilar artery (BAO) is a rare cause of stroke, making up approximately 1% of all cases. Ischemic stroke within the basilar artery is associated with serious complications and high mortality (75-91%). BAO may occur initially in the form of mild prodromal symptoms with neurological disorders, the consequences of which can lead to death. For these reasons, BAO requires rapid diagnosis and treatment. We report the case of a 26-year-old man who suffered basilar artery occlusion and was treated with endovascular therapy. The patient was disqualified from intra-venous thrombolysis and endovascular treatment due to exceeding the therapeutic time window. Despite this, due to the location of ischemia and age of the patient, it was decided to proceed with a mechanical thrombectomy (TM). Vessel patency was restored using the Solitaire FR stent. Treatment continued with antiplatelet therapy. Despite a significant overshoot of the time window the procedure was successful and complete recanalization was achieved. During hospitalization, significant neurological symptom reductions were observed. There is no accurate data on which method of treatment of ischemic stroke is best for BAO. Expectations about the effectiveness of endovascular techniques are high.

  1. Improvement of Stent Retriever Design and Efficacy of Mechanical Thrombectomy in a Flow Model

    SciTech Connect

    Wenger, Katharina; Nagl, Frank; Wagner, Marlies Berkefeld, Joachim

    2013-02-15

    In vitro experiments were performed to evaluate the efficacy of mechanical intracranial thrombectomy comparing the newly developed Aperio stent retriever and standard devices for stroke treatment. The Aperio (A), with an increased working length of 4 cm and a special cell design for capturing and withholding clots, was compared to three benchmark devices: the Solitaire retrievable stent (B), the Merci X6 (C), and the Merci L5 retriever (D). In a vascular glass model with pulsatile flow, reminiscent of the M1 segment of the middle cerebral artery, we repeatedly induced occlusion by generating thrombi via a modified Chandler loop system. The numbers of recanalization attempts, peripheral embolizations, and recanalizations at the site of occlusion were recorded during 10 retrieval experiments with each device. Eleven devices were able to remove the blood clots from the occluded branch. In 34 of 40 experiments, restoration of flow was obtained in 1-3 attempts. The main differences between the study devices were observed in terms of clot withholding and fragmentation during retrieval. Although there was only one fragmentation recorded for device A, disengagement of the whole clot or peripheral embolization of fragments occurred more frequently (5-7 times) with devices B, C, and D. In a vascular model, the design of device A was best at capturing and withholding thrombi during retrieval. Further study will be necessary to see whether this holds true in clinical applications.

  2. Acute Pancreatitis after Percutaneous Mechanical Thrombectomy: Case Report and Review of the Literature

    SciTech Connect

    Hershberger, Richard C. Bornak, Arash; Aulivola, Bernadette; Mannava, Krishna

    2011-02-15

    Purpose: We describe a case of severe acute pancreatitis after percutaneous mechanical thrombectomy (PMT) and review the literature for the occurrence of this complication. Materials and Methods: A 53-year-old man with a history of bilateral external iliac artery stent placement sought care for acute onset of lifestyle-limiting left claudication. Angiography confirmed left external iliac stent occlusion, and PMT with the AngioJet Xpeedior catheter (Possis Medical, Minneapolis MN) was performed. Results: After PMT of the occluded external iliac artery, a residual in-stent stenosis required the placement of a second iliac stent. The procedure was complicated by severe acute pancreatitis. Other causes of pancreatitis were eliminated during the patient's hospital stay. A literature review revealed nine cases of acute pancreatitis after PMT. Conclusion: Although rare, pancreatitis can be a devastating complication of PMT. The development of pancreatitis seems to be related to the products of extensive hemolysis triggering an inflammatory process. To prevent this complication, we recommend that close attention be paid to the duration and extent of PMT, thereby avoiding extensive hemolysis and subsequent complications.

  3. Mechanical thrombectomy with ‘ADAPT’ technique by transcervical access in acute ischemic stroke

    PubMed Central

    Remollo, Sebastian; García, Maria Rosa; Hidalgo, Cristina; Hernández-Perez, Maria; Ciorba, Mihaela

    2015-01-01

    Background The mechanical thrombectomy (MT) for endovascular clot retrieval has dramatically improved successful revascularization and clinical outcome in selected acute stroke patients. MT is typically performed via a transfemoral approach, but catheterization of the occluded vessel can be problematic in cases of extensive vessel tortuosity. We describe a case of MT with the ‘ADAPT’ technique by direct carotid access due to an inability to catheterize the ICA by a transfemoral approach for acute cerebral ischemia in the setting of left MCA occlusion. Excellent angiographic and good clinical results were obtained without any complications. Case report An 80-year-old woman was admitted with a stroke by occlusion of the left MCA, with an NIHSS: 11, and an ASPECT: 7 in the CT. Under sedation a transfemoral angiography was performed, but after multiple attempts, it was impossible to make a stable catheterization of the left CCA. A transcervical approach was pursued. With ultrasound guidance the CCA was catheterized. Using the ‘ADAPT’ technique, we performed a successful MT. Post-procedure angiography (at 14 minutes) demonstrated recanalization of the entire left MCA (TICI: 3), without complications. The carotid access point was closed with a percutaneous closure. Control TC at 24 h showed a slight hypodensity in the left lenticular nucleus, and loss of gray-white matter differentiation in the adjacent cortex. Neurologically, the patient presented with progressive improvement. At discharge, she had an NIHSS: 0, mRS: 0 and Barthel: 100. Conclusions MT by direct carotid access is an effective alternative technique in those cases where it is not accessible by a transfemoral approach. PMID:26443297

  4. Protected Iliofemoral Venous Thrombectomy

    PubMed Central

    Neri, Eugenio; Civeli, Letizia; Benvenuti, Antonio; Toscano, Thomas; Miraldi, Fabio; Capannini, Gianni; Muzzi, Luigi; Sassi, Carlo

    2002-01-01

    Although thromboembolism is uncommon during pregnancy and the postpartum period, physicians should be alert to the possibility because the complications, such as pulmonary embolism, are often life threatening. Pregnant women who present with thromboembolic occlusion are particularly difficult to treat because thrombolysis is hazardous to the fetus and surgical intervention by any of several approaches is controversial. A 22-year-old woman, in her 11th week of gestation, experienced an episode of pulmonary embolism and severe ischemic venous thrombosis of the left lower extremity. The cause was determined to be a severe protein S deficiency in combination with compression of the left iliac vein by the enlarged uterus. The patient underwent emergency insertion of a retrievable vena cava filter and surgical iliofemoral venous thrombectomy with concomitant creation of a temporary femoral arteriovenous fistula. The inferior vena cava filter was inserted before the venous thrombectomy to prevent pulmonary embolism from clots dislodged during thrombectomy. When the filter was removed, medium-sized clots were found trapped in its coils, indicating the effectiveness of this approach. The operation resolved the severe ischemic venous thrombosis of the left leg, and the patency of the iliac vein was maintained throughout the pregnancy without embolic recurrence. At full term, the woman spontaneously delivered an 8-lb, 6-oz, healthy male infant. (Tex Heart Inst J 2002;29:130–2) PMID:12075871

  5. Mechanical thrombectomy with the Solitaire AB stent for treatment of acute basilar artery occlusion: A single-center experience.

    PubMed

    Du, Shiwei; Mao, Gengsheng; Li, Dongmei; Qiu, Ming; Nie, Qingbin; Zhu, Haibo; Yang, Yang; Zhang, Youping; Li, Youxiang; Wu, Zhongxue

    2016-10-01

    Basilar artery occlusion (BAO) remains one of the most devastating subtypes of ischemic stroke, and prognosis is poor if early recanalization is not achieved. The purpose of this study was to evaluate the safety and technical feasibility of mechanical thrombectomy with the Solitaire AB stent (Covidien, Irvine, CA, USA) for the treatment of acute BAO through a single-center experience. Twenty-one patients with acute BAO were treated with mechanical thrombectomy with the Solitaire AB stent device between 1st September 2011 and 1st December 2014. Recanalization was assessed using the Thrombolysis in Cerebral Infarction (TICI) scale system. Clinical outcome was established at discharge by The National Institute of Health Stroke Scale (NIHSS), and the mean time from symptom onset to recanalization determined. Authors had access to identifying information during or after data collection. The clinical status of patients on admission was severe, with a mean NIHSS score of 25.57±5.20 (range: 16-38), and the number of patients with TICI 2b or 3 was 0. The mean time from symptom onset to recanalization was 579.00±188.78min (range: 360-960min). At 3-month follow-up, eight (38.1%) patients had a good clinical outcome. At follow-up, the trial of ORG 10172 in acute stroke treatment (TOAST) classification was large-vessel atherosclerosis in 13 patients (61.9%), cardioembolic in seven patients (33.3%), and undetermined in one patient (4.8%). In our series, application of the Solitaire AB stent retriever in acute BAO resulted in a high recanalization rate without procedural complications, and with good clinical outcome. Further prospective trials are needed to confirm the potential clinical benefit of this treatment approach. PMID:27312281

  6. A Comparison between Mechanical Thrombectomy and Intra-arterial Fibrinolysis in Acute Basilar Artery Occlusion: Single Center Experiences

    PubMed Central

    Jung, Seunguk; Jung, Cheolkyu; Bae, Yun Jung; Choi, Byung Se; Kim, Jae Hyoung; Lee, Sang-Hwa; Chang, Jun Young; Kim, Beom Joon; Han, Moon-Ku; Bae, Hee-Joon; Kwon, Bae Ju; Cha, Sang-Hoon

    2016-01-01

    Background and Purpose Recent advances in intra-arterial techniques and thrombectomy devices lead to high rate of recanalization. However, little is known regarding the effect of the evolvement of endovascular revascularization therapy (ERT) in acute basilar artery occlusion (BAO). We compared the outcome of endovascular mechanical thrombectomy (EMT) versus intra-arterial fibrinolysis (IAF)-based ERT in patients with acute BAO. Methods After retrospectively reviewed a registry of consecutive patients with acute ischemic stroke who underwent ERT from September 2003 to February 2015, 57 patients with acute BAO within 12 hours from stroke onset were enrolled. They were categorized as an IAF group (n=24) and EMT group (n=33) according to the primary technical option. We compared the procedural and clinical outcomes between the groups. Results The time from groin puncture to recanalization was significantly shorter in the EMT group than in the IAF group (48.5 [25.3 to 87.8] vs. 92 [44 to 179] minutes; P=0.02) The rate of complete recanalization was significantly higher in the EMT group than in the IAF group (87.9% vs 41.7%; P<0.01). The good outcome of the modified Rankin Scale score≤2 at 3 months was more frequent in the EMT group than in the IAF group, but it was not statistically significant (39.4% vs 16.7%; P=0.06). Conclusions EMT-based ERT in patients with acute BAO is superior to IAF-based ERT in terms of the reduction of time from groin puncture to recanalization and the improvement of the rate of complete recanalization. PMID:27283281

  7. Combination of Surgical Thrombectomy and Direct Thrombolysis in Acute Abdomen with Portal and Superior Mesenteric Vein Thrombosis.

    PubMed

    Jung, Hyuk Jae; Lee, Sang Su

    2014-12-01

    Portal vein (PV) thrombosis (PVT) is a rare condition with development of thrombosis in the PV and its branches. Further extension to the splenic and superior mesenteric vein (SMV) causes intestinal infarction, with a reported mortality of up to 50%. A variety of treatments for PVT exist including anticoagulation, thrombolysis, surgical thrombectomy, insertion of shunts, bypass surgery, and liver transplantation. We experienced a case of successfully treated by surgical thrombectomy with direct thrombolysis into the thrombosed-PV and SMV. A 31-year-old male presented worsening abdominal pain for one week. Preoperative contrast enhanced computed tomography scan revealed complete PVT extending to splenic vein and SMV. The PV was accessed surgically and opened by thrombectomy; visual inspection confirmed proximal and distal flow. Urokinase was administered directly into the inferior mesenteric vein with successful decrease in thrombus burden. The complete angiography showed complete dissolution of thrombosis in PV and SMV.

  8. Thrombectomy and Catheter-Directed Thrombolysis Combined With Antithrombin Concentrate for Treatment of Antithrombin Deficiency Complicated by Acute Deep Vein Thrombosis That Is Refractory to Anticoagulation.

    PubMed

    Maeba, Hirofumi; Seno, Takeshi; Shiojima, Ichiro

    2016-09-28

    A 22-year-old male was admitted to our hospital with deep vein thrombosis that was complicated by antithrombin deficiency. This deficiency was refractory to anticoagulation therapy. Although catheter-directed thrombolysis could not reperfuse the total occlusion in the left deep vein, a combination of thrombectomy, catheter-directed thrombolysis, and antithrombin concentrate treatment was able to dissolve the clots and ameliorate the blood flow into the left deep vein. Antithrombin concentrate administration would be effective in the treatment of antithrombin deficiency with medical refractory deep vein thrombosis.

  9. AngioJet thrombectomy.

    PubMed

    Lee, Michael S; Singh, Varinder; Wilentz, James R; Makkar, Raj R

    2004-10-01

    The AngioJet rheolytic thrombectomy system is designed to remove thrombus with the Venturi-Bernoulli effect, with multiple high-velocity, high-pressure saline jets which are introduced through orifices in the distal tip of the catheter to create a localized low-pressure zone, resulting in a vacuum effect with the entrainment and dissociation of bulky thrombus. Rheolytic thrombectomy with the AngioJet catheter can reduce the thrombus burden in the setting of AMI and degenerated SVGs. The long-term follow-up appears to be favorable in patients treated with rheolytic thrombectomy in the setting of acute myocardial infarction over conventional primary angioplasty. PMID:15505358

  10. Safety and Efficacy of Mechanical Thrombectomy Using Stent Retrievers in the Endovascular Treatment of Acute Ischaemic Stroke: A Systematic Review

    PubMed Central

    Puñal-Riobóo, Janet; Atienza, Gerardo; Blanco, Miguel

    2015-01-01

    Background The treatment of choice for acute ischaemic stroke is the intravenous administration of recombinant tissue plasminogen activator within 3-4.5 h of symptom onset. However, the use of a thrombolytic would be limited by its narrow therapeutic window and contraindications. As a result, in recent years, techniques such as mechanical thrombectomy have emerged, which employ thrombus retrieval devices, such as stent retrievers (Solitaire™, Trevo® or Revive™), whose safety and efficacy in the endovascular treatment of acute ischaemic stroke is analysed in this article. Methods A systematic literature search was undertaken until March 2015. The quality of evidence was assessed according to the GRADE methodology. A meta-analysis of the results of randomised controlled trials (RCTs) was performed, and the weighted average for the case series' sample size was calculated (Review Manager v5.2 and SPSS v19). Results Seventeen primary studies (2 RCTs, Solitaire™ and Trevo® vs. Merci®, and 15 case series) were selected. The RCT results show that stent retrievers have a safety profile similar to the Merci® device. However, both Solitaire™ and Trevo® achieved a higher recanalisation success rate (OR, 4.56; 95% CI, 2.63-7.90; p < 0.00001) and appropriate clinical outcome at 90 days (OR, 2.54; 95% CI, 1.52-4.25; p < 0.0004), although the 90-day mortality rate was similar in both groups (OR, 0.75; 95% CI, 0.17-3.37; p = 0.70). Conclusions Stent retrievers appear to be safe and effective devices, achieving high recanalisation rates and good clinical outcomes in the endovascular treatment of patients with acute ischaemic stroke due to the occlusion of intracranial arteries in comparison with the clot retriever Merci®. PMID:26279662

  11. Mechanical thrombectomy in acute ischemic stroke: Consensus statement by ESO-Karolinska Stroke Update 2014/2015, supported by ESO, ESMINT, ESNR and EAN.

    PubMed

    Wahlgren, Nils; Moreira, Tiago; Michel, Patrik; Steiner, Thorsten; Jansen, Olav; Cognard, Christophe; Mattle, Heinrich P; van Zwam, Wim; Holmin, Staffan; Tatlisumak, Turgut; Petersson, Jesper; Caso, Valeria; Hacke, Werner; Mazighi, Mikael; Arnold, Marcel; Fischer, Urs; Szikora, Istvan; Pierot, Laurent; Fiehler, Jens; Gralla, Jan; Fazekas, Franz; Lees, Kennedy R

    2016-01-01

    The original version of this consensus statement on mechanical thrombectomy was approved at the European Stroke Organisation (ESO)-Karolinska Stroke Update conference in Stockholm, 16-18 November 2014. The statement has later, during 2015, been updated with new clinical trials data in accordance with a decision made at the conference. Revisions have been made at a face-to-face meeting during the ESO Winter School in Berne in February, through email exchanges and the final version has then been approved by each society. The recommendations are identical to the original version with evidence level upgraded by 20 February 2015 and confirmed by 15 May 2015. The purpose of the ESO-Karolinska Stroke Update meetings is to provide updates on recent stroke therapy research and to discuss how the results may be implemented into clinical routine. Selected topics are discussed at consensus sessions, for which a consensus statement is prepared and discussed by the participants at the meeting. The statements are advisory to the ESO guidelines committee. This consensus statement includes recommendations on mechanical thrombectomy after acute stroke. The statement is supported by ESO, European Society of Minimally Invasive Neurological Therapy (ESMINT), European Society of Neuroradiology (ESNR), and European Academy of Neurology (EAN).

  12. Mechanical Thrombectomy Using Solitaire in a 6-Year-Old Child.

    PubMed

    Huded, Vikram; Kamath, Vikram; Chauhan, Bhumir; de Souza, Romnesh; Nair, Rithesh; Sapare, Anil; Kekatpure, Minal

    2015-05-01

    A six-year-old boy was diagnosed as recurrent posterior circulation stroke secondary to basilar artery occlusion with rapid progression of symptoms. Etiology of stroke was a dissection of V3 segment of left vertebral artery, which was treated using endovascular technique 26 hours after worsening of symptoms. Since the guidelines for acute revascularization in pediatric stroke are not well established, there is limited experience in the use of mechanical devices for acute ischemic stroke revascularization in children. To our knowledge, this is one of the youngest reported cases of acute ischemic stroke from Asia managed with newer mechanical clot removal devices. PMID:26060522

  13. Mechanical Thrombectomy Using Solitaire in a 6-Year-Old Child.

    PubMed

    Huded, Vikram; Kamath, Vikram; Chauhan, Bhumir; de Souza, Romnesh; Nair, Rithesh; Sapare, Anil; Kekatpure, Minal

    2015-05-01

    A six-year-old boy was diagnosed as recurrent posterior circulation stroke secondary to basilar artery occlusion with rapid progression of symptoms. Etiology of stroke was a dissection of V3 segment of left vertebral artery, which was treated using endovascular technique 26 hours after worsening of symptoms. Since the guidelines for acute revascularization in pediatric stroke are not well established, there is limited experience in the use of mechanical devices for acute ischemic stroke revascularization in children. To our knowledge, this is one of the youngest reported cases of acute ischemic stroke from Asia managed with newer mechanical clot removal devices.

  14. Acute Superior Mesenteric Venous Thrombosis: Transcatheter Thrombolysis and Aspiration Thrombectomy Therapy by Combined Route of Superior Mesenteric Vein and Artery in Eight Patients

    SciTech Connect

    Yang, Shuofei Liu, Baochen Ding, Weiwei He, Changsheng Wu, Xingjiang Li, Jieshou

    2015-02-15

    PurposeTo assess the feasibility, effectiveness, and safety of catheter-directed thrombolysis and aspiration thrombectomy therapy by combined route of superior mesenteric vein and artery (SMV+SMA) for acute superior mesenteric venous thrombosis (ASMVT).MethodsThis retrospective study reviewed eight ASMVT patients with transcatheter direct thrombolysis and aspiration thrombectomy therapy via SMV and indirect thrombolysis via SMA during a period of 14 months. The demographics, etiology, risk factors, therapeutic effect, complications, mortality, and follow-up of the study population were assessed. Anatomic and imaging classification of location and extent of thrombus at diagnosis and degree of thrombus lysis were described.ResultsTechnical success was achieved with substantial improvement in symptoms and thrombus resolution after thrombolytic therapy in all patients. The local urokinase infusion by SMA and SMV was performed for 5–7 (6.13 ± 0.83) and 7–15 (12 ± 2.51) days. Anticoagulation was performed catheter-directed and then orally throughout hospitalization and after discharge. Four patients required delayed localized bowel resection after thrombolytic therapy with no death. Thrombolytic therapy was not interrupted despite minor bleeding at the puncture site in two patients and sepsis in another two postoperatively. Nearly complete removal of thrombus was demonstrated by contrast-enhanced CT scan and portography before discharge. Patients were discharged in 10–27 (19.25 ± 4.89) days after admission. No recurrence developed during the follow-up of 10–13 (12.13 ± 0.99) months.ConclusionsCatheter-directed thrombolytic and aspiration therapy via SMV+SMA is beneficial for ASMVT in avoiding patient death, efficient resolving thrombus, rapid improving symptoms, reversing extensive intestinal ischemia, averting bowel resection, or localizing infarcted bowel segment and preventing short bowel syndrome.

  15. Ileofemoral venous thrombectomy.

    PubMed

    Lindhagen, J; Haglund, M; Haglund, U; Holm, J; Scherstén, T

    1978-01-01

    Twentyeight patients with ileofemoral venous thrombosis were treated surgically. Five of the patients had moderate degree of venous congestion, 18 patients had phlegmasia alba dolens and five patients had phlegmasia coerulea dolens. The mean age was 54 years, range 15-80 years, and 15 were men and 13 were women. In all cases the thrombosis was verified by phlebography. Thrombectomy was performed with a Fogarty venous thrombectomy catheter. Peroperative phlebography was used in most cases to guarantee complete extraction of thrombotic material. No operative pulmonary embolism or mortality was encountered. Postoperative continuous heparin infusion in the thrombectomized segment was used for the first week followed by dicumarol treatment. The patients were followed from 6 months to 4 years postoperatively. In two patients thrombectomy was not possible to perform. One of these patients developed a pronounced postthrombotic syndrome, the other developed venous congestion of more moderate degree. Excellent long-term time results were obtained in 82% of the patients and satisfactory in 14%. Thrombectomy is an efficient treatment of ileofemoral venous thrombosis.

  16. Mechanical Thrombectomy-Ready Comprehensive Stroke Center Requirements and Endovascular Stroke Systems of Care: Recommendations from the Endovascular Stroke Standards Committee of the Society of Vascular and Interventional Neurology (SVIN).

    PubMed

    English, Joey D; Yavagal, Dileep R; Gupta, Rishi; Janardhan, Vallabh; Zaidat, Osama O; Xavier, Andrew R; Nogueira, Raul G; Kirmani, Jawad F; Jovin, Tudor G

    2016-03-01

    Five landmark multicenter, prospective, randomized, open-label, blinded end point clinical trials have recently demonstrated significant clinical benefit of endovascular therapy with mechanical thrombectomy in acute ischemic stroke (AIS) patients presenting with proximal intracranial large vessel occlusions. The Society of Vascular and Interventional Neurology (SVIN) appointed an expert writing committee to summarize this new evidence and make recommendations on how these data should guide emergency endovascular therapy for AIS patients. PMID:27051410

  17. Mechanical Thrombectomy-Ready Comprehensive Stroke Center Requirements and Endovascular Stroke Systems of Care: Recommendations from the Endovascular Stroke Standards Committee of the Society of Vascular and Interventional Neurology (SVIN)

    PubMed Central

    English, Joey D.; Yavagal, Dileep R.; Gupta, Rishi; Janardhan, Vallabh; Zaidat, Osama O.; Xavier, Andrew R.; Nogueira, Raul G.; Kirmani, Jawad F.; Jovin, Tudor G.

    2016-01-01

    Five landmark multicenter, prospective, randomized, open-label, blinded end point clinical trials have recently demonstrated significant clinical benefit of endovascular therapy with mechanical thrombectomy in acute ischemic stroke (AIS) patients presenting with proximal intracranial large vessel occlusions. The Society of Vascular and Interventional Neurology (SVIN) appointed an expert writing committee to summarize this new evidence and make recommendations on how these data should guide emergency endovascular therapy for AIS patients. PMID:27051410

  18. Pharmacomechanical thrombectomy for salvage of TIPSS via successful -clearance of occlusive porto-splenic venous thrombosis.

    PubMed

    Tavare, A N; Wigham, A J; Goode, A

    2016-03-01

    Transjugular intrahepatic porto-systemic shunt (TIPSS) is increasingly used to treat chronic portal vein thrombosis. However shunt thrombosis is a recognised early complication, particularly in those with thrombophilia. We outline a case of non-cirrhotic portal hypertension secondary to chronic portal vein occlusion where TIPSS was successfully performed but rapidly complicated by shunt thrombosis with extension into the portal and splenic veins. Mechanical thrombectomy and low dose systemic pharmacological thrombolysis were of limited benefit. Combined pharmacomechanical thrombectomy with the Trellis system restored -patency of the TIPSS, portal and splenic veins, with resultant good flow into the TIPSS. The patient remains well three months post-procedure. We describe the first case where the Trellis system has been successfully used to clear occlusive porto-splenic thrombus and restore flow through a blocked TIPSS.

  19. Does Mechanical Thrombectomy in Acute Embolic Stroke Have Long-term Side Effects on Intracranial Vessels? An Angiographic Follow-up Study

    SciTech Connect

    Kurre, Wiebke Perez, Marta Aguilar; Horvath, Diana; Schmid, Elisabeth; Baezner, Hansjoerg; Henkes, Hans

    2013-06-15

    Purpose. Mechanical thrombectomy (mTE) proved to be effective treating acute vessel occlusions with an acceptable rate of procedural complications. Potential long-term side effects of the vessel wall trauma caused by mechanical irritation of the endothelium are unknown up to now. Methods. From a retrospectively established database of 640 acute stroke treatments, we selected 261 patients with 265 embolic vessel occlusions treated successfully by mTE without permanent implantation of a stent. Analysis comprised the type of devices used and the number of passes performed. Digital subtraction angiography immediately after treatment was evaluated for vasospasm, dissection, and extravasation. Control angiographic images were evaluated for any morphological change compared to the immediate posttreatment angiographic run. Results. Recanalization was achieved with a median of one (range 1-10) mTE maneuvers. Vasospasm occurred in 69 territories (26.0 %) and was treated with glyceroltrinitrate in three. Dissection was observed in one vessel (0.4 %). Intraprocedural hemorrhage in two patients (0.8 %) was either wire or device induced. Follow-up digital subtraction angiography was available for 117 territories after a median of 107 days, revealing target vessel occlusion in one segment (0.9 %) and a de novo stenosis of four segments (3.4 %). All findings were clinically asymptomatic. Posttreatment vasospasm was more frequent in patients with de novo stenosis and occlusion (p = 0.038). Conclusion. De novo stenoses and occlusions occur in a small proportion of patients after mTE. Because all lesions were clinically asymptomatic, this finding does not affect the overall benefit of the treatment. Vasospasm may predict late vessel wall changes.

  20. Does Preinterventional Flat-Panel Computer Tomography Pooled Blood Volume Mapping Predict Final Infarct Volume After Mechanical Thrombectomy in Acute Cerebral Artery Occlusion?

    SciTech Connect

    Wagner, Marlies; Kyriakou, Yiannis; Mesnil de Rochemont, Richard du; Singer, Oliver C.; Berkefeld, Joachim

    2013-08-01

    PurposeDecreased cerebral blood volume is known to be a predictor for final infarct volume in acute cerebral artery occlusion. To evaluate the predictability of final infarct volume in patients with acute occlusion of the middle cerebral artery (MCA) or the distal internal carotid artery (ICA) and successful endovascular recanalization, pooled blood volume (PBV) was measured using flat-panel detector computed tomography (FPD CT).Materials and MethodsTwenty patients with acute unilateral occlusion of the MCA or distal ACI without demarcated infarction, as proven by CT at admission, and successful Thrombolysis in cerebral infarction score (TICI 2b or 3) endovascular thrombectomy were included. Cerebral PBV maps were acquired from each patient immediately before endovascular thrombectomy. Twenty-four hours after recanalization, each patient underwent multislice CT to visualize final infarct volume. Extent of the areas of decreased PBV was compared with the final infarct volume proven by follow-up CT the next day.ResultsIn 15 of 20 patients, areas of distinct PBV decrease corresponded to final infarct volume. In 5 patients, areas of decreased PBV overestimated final extension of ischemia probably due to inappropriate timing of data acquisition and misery perfusion.ConclusionPBV mapping using FPD CT is a promising tool to predict areas of irrecoverable brain parenchyma in acute thromboembolic stroke. Further validation is necessary before routine use for decision making for interventional thrombectomy.

  1. Sinus thrombectomy for purulent cerebral venous sinus thrombosis utilizing a novel combination of the Trevo stent retriever and the Penumbra ACE aspiration catheter: the stent anchor with mobile aspiration technique.

    PubMed

    Mascitelli, Justin R; Pain, Margaret; Zarzour, Hekmat K; Baxter, Peter; Ghatan, Saadi; Mocco, J

    2015-01-01

    Intracranial complications of sinusitis are rare but life threatening. We present a case of a 17-year-old woman with sinusitis who deteriorated over the course of 12 days from subdural empyema and global purulent cerebral venous sinus thrombosis. The patient was managed with surgery and mechanical thrombectomy utilizing a novel 'stent anchor with mobile aspiration technique', in which a Trevo stent retriever (Stryker) was anchored in the superior sagittal sinus (SSS) while a 5 MAX ACE reperfusion catheter (Penumbra) was passed back and forth from the SSS to the sigmoid sinus with resultant dramatic improvement in venous outflow. The patient was extubated on postoperative day 3 and was discharged with minimal lower extremity weakness on postoperative day 11. This is the first report using the Trevo stent retriever for sinus thrombosis. It is important to keep these rare complications in mind when evaluating patients with oral and facial infections. PMID:26002667

  2. Endovascular Mechanical Thrombectomy of an Occluded Superior Division Branch of the Left MCA for Acute Cardioembolic Stroke

    SciTech Connect

    Schumacher, H. C. Meyers, P. M.; Yavagal, D. R.; Harel, N. Y.; Elkind, M. S. V.; Mohr, J. P.; Pile-Spellman, J.

    2003-06-15

    Cardiac embolism accounts for a large proportion of ischemic stroke. Revascularization using systemic or intra-arterial thrombolysis is associated with increasing risks of cerebral hemorrhageas time passes from stroke onset. We report successful mechanicalthrombectomy from a distal branch of the middle cerebral artery (MCA)using a novel technique. A 72-year old man suffered an acute ischemic stroke from an echocardiographically proven ventricular thrombus due toa recent myocardial infarction. Intra-arterial administration of 4 mgrt-PA initiated at 5.7 hours post-ictus failed to recanalize an occluded superior division branch of the left MCA. At 6 hours,symptomatic embolic occlusion persisted. Mechanical extraction of the clot using an Attracter-18 device (Target Therapeutics, Freemont, CA) resulted in immediate recanalization of the MCA branch. Attracter-18 for acute occlusion of MCA branches may be considered in selected patients who fail conventional thrombolysis or are nearing closure of the therapeutic window for use of thrombolytic agents.

  3. Mechanical thrombectomy using Rotarex system and stent-in-stent placement for treatment of distal femoral artery occlusion secondary to stent fracture – a case report and literature review

    PubMed Central

    Dys, Krzysztof; Drelichowska-Durawa, Justyna; Dołega-Kozierowski, Bartosz; Lis, Michał; Sokratous, Kyriakos; Iwanowski, Wojciech; Drelichowski, Stanisław; Witkiewicz, Wojciech

    2013-01-01

    Summary Background: Treatment of peripheral arterial diseases may be distinguished into conservative and interventional management; the latter is divided into surgical and endovascular procedures. Management of peripheral artery stenosis and occlusion with vascular stents is associated with the risk of late complications such as restenosis, stent fracture or dislocation. Case Report: A 62-year-old woman with generalized atherosclerosis, particularly extensive in lower limb arteries, was admitted to the Department of Angiology 11 months after having an endovascular procedure performed due to critical ischemia of left lower limb. Because of stent occlusion, a decision to perform angiographic examination of lower limb arteries was made. Examination revealed occlusion of the superficial femoral artery along its entire length, including previously implanted stents. Distal stent was fractured with slight dislocation of the proximal segment. A decision was made to perform mechanical thrombectomy using a Rotarex system followed by a stent-in-stent placement procedure. Follow-up angiography and ultrasound scan performed 24 hours after the procedure revealed a patent vessel with satisfactory blood flow. Discussion: Nowadays, imaging diagnostics of peripheral artery stenosis involves non-invasive examinations such as ultrasound, minimally invasive examinations such as angio-MRI and MDCT, or invasive examinations such as DSA and IVUS. DSA examinations are used to confirm significant stenosis or occlusion of a vessel, particularly when qualifying a patient for endovascular treatment. Due to their anatomic location, the superficial femoral artery and the popliteal artery are subject to various forces e.g. those exerted by the working muscles. Mechanical thrombectomy and atherectomy are efficient methods of arterial recanalization used in the treatment of acute, subacute or even chronic occlusions or stenosis of peripheral vessels. Conclusions: Frequency of angioplasty and

  4. Emergent Right Coronary Artery Thrombectomy with a Jet Aspiration Thrombectomy Catheter

    SciTech Connect

    Yamauchi, Teiyu; Furui, Shigeru; Isshiki, Takaaki; Toyoizumi, Hideki; Kohtake, Hiroshi; Takeshita, Kohji; Suzuki, Shigeru; Harasawa, Arimi; Sasaki, Yasushi

    1999-07-15

    A saline-jet aspiration thrombectomy (JAT) catheter was used in a patient with acute myocardial infarction. A right coronary arteriogram showed complete thrombotic occlusion at the proximal segment. With this catheter the thrombus was removed without complications in 5 sec. The patient underwent percutaneous transluminal coronary angioplasty and placement of a Palmaz-Schatz stent after successful thrombectomy. Thrombectomy with a JAT catheter was very useful in this patient.0.

  5. Massive Pulmonary Embolism: Treatment with the Rotarex Thrombectomy System

    SciTech Connect

    Liu Sheng; Shi Haibin; Gu Jianping; Yang Zhengqiang; Chen Liang; Lou Wensheng; He Xu; Zhou Weizhong; Zhou Chungao; Zhao Linbo; Xia Jinguo; Li Linsun

    2011-02-15

    This study was designed to evaluate the efficacy and safety of percutaneous mechanical thrombectomy (PMT) for acute massive pulmonary embolism (PE). Fourteen patients (8 men, 6 women) with a mean age of 55.4 (range, 38-71) years with acute massive PE were initially diagnosed by computed tomography (CT) and confirmed by pulmonary angiography. All patients presented with acute PE symptoms and hemodynamic compromise. Each patient was treated with Straub Rotarex thrombectomy device and five patients received additional thrombolysis. Technique success and clinical improvement were achieved in all patients without major complications. The mean pulmonary artery pressure (PAP) decreased from 37.6 {+-} 6.6 to 29 {+-} 6.4 mmHg (P < 0.01) after PMT. Partial arterial pressures of O{sub 2} (PaO{sub 2}) increased from 61.1 {+-} 9.2 to 88 {+-} 5.1 mmHg (P < 0.01). The Miller index was 0.67 {+-} 0.11 and 0.37 {+-} 0.13 (P < 0.01), respectively, before and after PMT (P < 0.01). Eleven patients had no recurrence of PE on a mean follow-up of 28.3 months, whereas the other three patients were lost to follow-up. The preliminary experience in our series suggests that the Straub Rotarex thrombectomy device, which has been utilized in peripheral arteries, also is useful for the treatment of acute massive PE.

  6. The Effectiveness of Additional Treatment Modalities after the Failure of Recanalization by Thrombectomy Alone in Acute Vertebrobasilar Arterial Occlusion

    PubMed Central

    Kim, Seong Mook; Sohn, Sung-Il; Hong, Jeong-Ho; Chang, Hyuk-Won; Lee, Chang-Young

    2015-01-01

    Objective Acute vertebrobasilar artery occlusion (AVBAO) is a devastating disease with a high mortality rate. One of the most important factors affecting favorable clinical outcome is early recanalization. Mechanical thrombectomy is an emerging treatment strategy for achieving a high recanalization rates. However, thrombectomy alone can be insufficient to complete recanalization, especially for acute stroke involving large artery atheromatous disease. The purpose of this study is to investigate the safety and efficacy of mechanical thrombectomy in AVBAO. Methods Fourteen consecutive patients with AVBAO were treated with mechanical thrombectomy. Additional multimodal treatments were intra-arterial (IA) thrombolysis, balloon angioplasty, or permanent stent placement. Recanalization by thrombectomy alone and multimodal treatments were assessed by the Thrombolysis in Cerebral Infarction (TICI) score. Clinical outcome was determined using the National Institutes of Health Stroke Scale (NIHSS) at 7 days and the modified Rankin Scale (mRS) at 3 months. Results Thrombectomy alone and multimodal treatments were performed in 10 patients (71.4%) and 4 patients (28.6%), respectively. Successful recanalization (TICI 2b-3) was achieved in 11 (78.6%). Among these 11 patients, 3 (27.3%) underwent multimodal treatment due to underlying atherosclerotic stenosis. Ten (71.4%) of the 14 showed NIHSS score improvement of >10. Overall mortality was 3 (21.4%) of 14. Conclusion We suggest that mechanical thrombectomy is safe and effective for improving recanalization rates in AVBAO, with low complication rates. Also, in carefully selected patients after the failure of recanalization by thrombectomy alone, additional multimodal treatment such as IA thrombolysis, balloons, or stents can be needed to achieve successful recanalization. PMID:26713141

  7. Percutaneous Venous Thrombectomy Using the Arrow-Trerotola Percutaneous Thrombolytic Device (PTD) with Temporary Caval Filtration: In Vitro Investigations

    SciTech Connect

    Wildberger, Joachim Ernst Haage, Patrick; Bovelander, Jan; Pfeffer, Joachim; Weiss, Claudia; Vorwerk, Dierk; Schmitz-Rode, Thomas; Guenther, Rolf W.

    2005-04-15

    Purpose. To evaluate the size and quantity of downstream emboli after thrombectomy using the Arrow-Trerotola Percutaneous Thrombolytic Device (PTD) with or without temporary filtration for extensive iliofemoral and iliocaval thrombi in an in vitro flow model. Methods. Iliocaval thrombi were simulated by clotted bovine blood in a flow model (semilucent silicone tubings, diameter 12-16 mm). Five experimental set-ups were performed 10 times each; thrombus particles and distribution were measured in the effluent. First, after retrograde insertion, mechanical thrombectomy was performed using the PTD alone. Then a modified self-expanding tulip-shaped temporary vena cava stent filter was inserted additionally at the beginning of each declotting procedure and removed immediately after the intervention without any manipulation within or at the filter itself. In a third step, the filter was filled with thrombus only. Here, two experiments were performed: Careful closure within the flow circuit without any additional fragmentation procedure and running the PTD within the filter lumen, respectively. In the final set-up, mechanical thrombectomy was performed within the thrombus-filled tubing as well as in the filter lumen. The latter was closed at the end of the procedure and both devices were removed from the flow circuit. Results. Running the PTD in the flow circuit without filter protection led to a fragmentation of 67.9% ({+-}7.14%) of the clot into particles {<=}500 {mu}m; restoration of flow was established in all cases. Additional placement of the filter safely allowed maceration of 82.9% ({+-}5.59%) of the thrombus. Controlled closure of the thrombus-filled filter within the flow circuit without additional mechanical treatment broke up 75.2% ({+-}10.49%), while additional mechanical thrombectomy by running the PTD within the occluded filter led to dissolution of 90.4% ({+-}3.99%) of the initial clot. In the final set-up, an overall fragmentation rate of 99.6% ({+-}0

  8. Massive Pulmonary Embolism: Percutaneous Emergency Treatment Using an Aspirex Thrombectomy Catheter

    SciTech Connect

    Popovic, Peter; Bunc, Matjaz

    2010-10-15

    Massive pulmonary embolism (PE) is a life-threatening condition with a high early mortality rate caused by acute right ventricular failure and cardiogenic shock. A 51-year-old woman with a massive PE and contraindication for thrombolytic therapy was treated with percutaneous mechanical thrombectomy using an Aspirex 11F catheter (Straub Medical AG, Wangs, Switzerland). The procedure was successfully performed and showed a good immediate angiographic result. The patient made a full recovery from the acute episode and was discharged on heparin treatment. Our case report indicates that in patients with contraindications to systemic thrombolysis, catheter thrombectomy may constitute a life-saving intervention for massive PE.

  9. Current opinion on iliofemoral venous thrombectomy.

    PubMed

    Stephens, G L

    1976-02-01

    Iliofemoral venous thrombosis is discussed and a technique of iliofemoral venous thrombectomy is presented. Operative phlebography is recommended. The personal recommendations of leading American vascular surgeons in treating the patient with acute iliofemoral venous thrombosis are presented. I recommend thrombectomy for phlegmasia cerulea dolens, and in previously healthy, young ambulatory patients with phlegmasia alba dolens who are seen within 48 hours following thrombosis and have failed to show clinical improvement after a trial of bed rest, elevation of the lower extremities, and intravenous heparin. The majority of patients seen with phlegmasia alba dolens will best be served with nonoperative treatment.

  10. Endovascular treatment of acute stroke with major vessel occlusion before approval of mechanical thrombectomy devices in Japan: Japanese Registry of Neuroendovascular Therapy (JR-NET) and JR-NET 2.

    PubMed

    Hayakawa, Mikito; Yamagami, Hiroshi; Sakai, Nobuyuki; Matsumaru, Yuji; Yoshimura, Shinichi; Toyoda, Kazunori

    2014-01-01

    The aim of this study was to clarify the general status and historical transition of endovascular therapy (EVT) of acute stroke with major vessel occlusion before approval of mechanical thrombectomy devices in Japan from January 2005 to December 2009. We extracted 1,409 acute ischemic stroke patients receiving EVT (513 women, 69.8 ± 11.8 years) from two nationwide registry studies, the Japanese Registry of Neuroendovascular Therapy (JR-NET) and JR-NET 2. The median baseline National Institutes of Health Stroke Scale (NIHSS) score was 18, and 81.3% of the patients received EVT within 6 hours after symptom onset. The culprit occluded arteries were the internal carotid artery (ICA) in 21.2%, middle cerebral artery (MCA) in 53.0%, and basilar artery (BA) in 20.6%. Intravenous thrombolysis was administered to 6.7% of the patients, and EVT mainly consisted of intra-arterial thrombolysis and percutaneous balloon angioplasty/balloon clot disruption. The final recanalization rate was 82.5%, and the clinical outcome was favorable in 35.8% and fatal in 11.6% at 30 days after onset or at discharge. There was no significant change in neurological severity at baseline throughout the study period, but the onset-to-treatment time became longer and the proportion of ICA or BA occlusion increased annually. Although the final recanalization rate was similar throughout the study period, the incidence of a favorable outcome tended to decreased annually from 41.0% to 29.0%. These results could be considered as baseline data that can be used to validate the beneficial effects of novel EVT devices in Japan.

  11. Effect of Coronary Thrombectomy in Cardiogenic Shock Complicating ST-Segment Elevation Myocardial Infarction.

    PubMed

    Suzuki, Makoto; Sumiyoshi, Tetsuya; Miyachi, Hideki; Yamashita, Jun; Yamasaki, Masao; Miyauchi, Katsumi; Yamamoto, Takeshi; Nagao, Ken; Tomoike, Hitonobu; Takayama, Morimasa

    2015-06-15

    Optimal coronary reflow is the critical key issue to ameliorate clinical outcomes in patients with cardiogenic shock complicating ST-segment elevation myocardial infarction (Shock-STEMI). We investigated our hypothesis that pre-percutaneous coronary intervention (PCI) procedural coronary thrombectomy may provide clinical advantages to attempt optimal coronary reflow in patients with Shock-STEMI. Of 7,650 patients with acute myocardial infarction registered in the Tokyo CCU Network Scientific Council from January 2009 to December 2011, a total of 180 consecutive patients (144 men, 68 ± 13 years) with Shock-STEMI who showed pre-PCI procedural Thrombolysis in Myocardial Infarction flow grade 0 (absent initial coronary flow) were recruited. Achievements of post-PCI procedural Thrombolysis in Myocardial Infarction flow grade 3 (optimal coronary reflow) and also in-hospital mortality were evaluated in those in accordance with and without coronary thrombectomy. Coronary thrombectomy was performed in 128 patients with Shock-STEMI (71% of all). Overall in-hospital mortality was 41% and that in anterior Shock-STEMI with a necessity of mechanical circulatory support increased by 59% (i.e., profound shock). Coronary thrombectomy did not affect any improvements in the achievement of optimal coronary reflow (65% vs 58%, p = 0.368) and in-hospital mortality (42% vs 37%, p = 0.484) in these patients. Even when focused on 76 patients with profound shock, neither an achievement of optimal coronary reflow (56% vs 47%, p = 0.518) nor in-hospital mortality (58% vs 65%, p = 0.601) were different between with and without coronary thrombectomy. Multivariate logistic analysis did not demonstrate any association of coronary thrombectomy (p = 0.798), left main Shock-STEMI (p = 0.258), and use of mechanical circulatory support (p = 0.119) except a concentration of hemoglobin (for each 1 g/dl increase, odds ratio 1.247, 95% confidence interval 1.035 to 1.531, p = 0.019) with optimal

  12. [Thrombectomy and plication of veins as a method of preventing pulmonary artery thromboembolism at a multidisciplinary surgical hospital].

    PubMed

    Galkin, S V; Pashin, N V; Dedyukhin, I G; Aleksandrov, A G; Lebedeva, M V

    2016-01-01

    The authors assessed efficacy and safety of the operation of plication of deep veins of lower extremities, pelvic veins, and the inferior vena cava as a method of preventing fatal pulmonary artery thromboembolism. A total of 48 patients were operated on. Of these, 23 patients belonged to traumatological-and-orthopaedical cohort, 3 to general surgical cohort, 4 to gynaecological, and 18 to vascular cohort (isolated deep vein thrombosis). The length of the floating head of the thrombus varied from 2 to 10 cm. The presence of a floating thrombus in traumatological, surgical and gynaecological patients, regardless of the length of the floating part was an absolute indication for thrombectomy and venous plication. Vascular patients were operated on in accordance with the National Guidelines (with the length of the thrombus floating portion of not less than 4 cm). In all cases, surgical management envisaged direct and indirect thrombectomy. Plication was always performed above the level of venotomy. It was shown that thrombectomy combined with plication of major veins is a reliable and safe method of prophylaxis, being in some cases the only possible method of preventing fatal pulmonary artery thromboembolism. The operation of plication makes it possible not to cancel a scheduled surgical intervention in patients with a detected floating thrombus of major veins. The operation of thrombectomy and plication above the level of the floating head of the thrombus may be considered an operation of choice in the conditions where there is no possibility to use endovascular methods of treatment (implantation of a cava filter, endovascular catheter thrombectomy), as well as in pregnant women. Restoration of the venous lumen occurs at safe terms spontaneously, not requiring repeat surgical intervention. Simultaneous plication of the vein does not complicate the course of the postoperative period of the main surgical intervention. Thrombectomy and plication do not lead to the

  13. Pulling Seton: Combination of mechanisms

    PubMed Central

    Izadpanah, Ahmad; Rezazadehkermani, Mohammad; Hosseiniasl, Seyed Mohammad; Farghadin, Afrouz; Ghahramani, Leila; Bananzadeh, Alimohammad; Roshanravan, Reza; Izadpanah, Ahad

    2016-01-01

    Background: Seton-based techniques are among popular methods for treating high type anal fistula. These techniques are categorized to cutting and noncutting regarding their mechanism of action. In this report we are about to describe a new technique, which is a combination of both mechanisms; we call it Pulling Seton. Materials and Methods: In this technique after determining internal and external orifice of fistula, fistulectomy is done from both ends to the level of external sphincteric muscle. Finally, a remnant of fistula, which remains beneath external sphincteric muscle is excised, and Seton is passed instead of it and tied externally. After the wound heals, patient is asked to pull down the Seton for 3–4 min, 4 times a day. We prospectively enrolled 201 patients with high type anal fistula in this study. Results: Seton gradually passes through external sphincteric muscle till it is displaced outwards or removed by a surgeon via a small incision. 94% of patients treated by this method accomplished their treatment completely without recurrence. None of the patients developed permanent fecal or gas incontinence. Only 5% of patients developed with recurrence of fistula. Since Seton traction is not permanent in this technique, Seton cuts external sphincter slowly, and minimal rate of incontinence is reported. Conclusion: Pulling Seton seems to be an efficient way in treating high type anal fistula with minimal rate of recurrence and complications such as incontinence and authors suggest further randomized studies to compare its efficacy with other Seton-based techniques. PMID:27169099

  14. Safety and Efficacy of Solitaire Stent Thrombectomy

    PubMed Central

    Campbell, Bruce C.V.; Hill, Michael D.; Rubiera, Marta; Menon, Bijoy K.; Demchuk, Andrew; Donnan, Geoffrey A.; Roy, Daniel; Thornton, John; Dorado, Laura; Bonafe, Alain; Levy, Elad I.; Diener, Hans-Christoph; Hernández-Pérez, María; Pereira, Vitor Mendes; Blasco, Jordi; Quesada, Helena; Rempel, Jeremy; Jahan, Reza; Davis, Stephen M.; Stouch, Bruce C.; Mitchell, Peter J.; Jovin, Tudor G.; Saver, Jeffrey L.

    2016-01-01

    Background and Purpose— Recent positive randomized trials of endovascular therapy for ischemic stroke used predominantly stent retrievers. We pooled data to investigate the efficacy and safety of stent thrombectomy using the Solitaire device in anterior circulation ischemic stroke. Methods— Patient-level data were pooled from trials in which the Solitaire was the only or the predominant device used in a prespecified meta-analysis (SEER Collaboration): Solitaire FR With the Intention for Thrombectomy as Primary Endovascular Treatment (SWIFT PRIME), Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion With Emphasis on Minimizing CT to Recanalization Times (ESCAPE), Extending the Time for Thrombolysis in Emergency Neurological Deficits—Intra-Arterial (EXTEND-IA), and Randomized Trial of Revascularization With Solitaire FR Device Versus Best Medical Therapy in the Treatment of Acute Stroke Due to Anterior Circulation Large Vessel Occlusion Presenting Within Eight Hours of Symptom Onset (REVASCAT). The primary outcome was ordinal analysis of modified Rankin Score at 90 days. The primary analysis included all patients in the 4 trials with 2 sensitivity analyses: (1) excluding patients in whom Solitaire was not the first device used and (2) including the 3 Solitaire-only trials (excluding ESCAPE). Secondary outcomes included functional independence (modified Rankin Score 0–2), symptomatic intracerebral hemorrhage, and mortality. Results— The primary analysis included 787 patients: 401 randomized to endovascular thrombectomy and 386 to standard care, and 82.6% received intravenous thrombolysis. The common odds ratio for modified Rankin Score improvement was 2.7 (2.0–3.5) with no heterogeneity in effect by age, sex, baseline stroke severity, extent of computed tomography changes, site of occlusion, or pretreatment with alteplase. The number needed to treat to reduce disability was 2.5 and for an extra patient to achieve independent

  15. Antegrade rheolytic thrombectomy and thrombolysis for superior sagittal sinus thrombosis using burr hole access

    PubMed Central

    Lee, Darrin J; Latchaw, Richard E; Dahlin, Brian C; Dong, Paul R; Verro, Piero; Muizelaar, J Paul; Shahlaie, Kiarash

    2014-01-01

    Superior sagittal sinus (SSS) thrombosis has high morbidity and mortality, and urgent recanalization is critical for severe cases. Standard endovascular techniques for thrombolysis and thrombectomy use retrograde venous access, an approach that may be unsuccessful in cases with extensive firm clot burden involving the dural sinuses distal to the SSS. An anterior open transcranial approach to the SSS for catheter sheath placement to facilitate antegrade mechanical thrombectomy and thrombolysis of the SSS and more distal sinuses has not been previously described. Here we describe a case in which multiple unsuccessful attempts at retrograde endovascular access were attempted. Thus, a burr hole over the anterior SSS was performed for daily endovascular antegrade procedures using the Angiojet rheolytic catheter device and chemical thrombolysis. Near-complete recanalization of the SSS was achieved with venous outflow via dilated left transverse and left sigmoid sinuses, along with significant collateral flow in multiple cerebral veins. PMID:24692369

  16. Massive air embolus treated with rheolytic thrombectomy.

    PubMed

    Dudar, Basil M; Kim, Henry E

    2007-07-01

    The incidence of air embolism during diagnostic cardiac catheterization and percutaneous coronary intervention is reported at a rate of 0.84% and 0.24%. Although there is no optimal technique to restore blood flow after blockage by air emboli, treatment options include manual aspiration or forcefully injecting saline, with auxiliary supportive measures like 100% oxygen or an intra-aortic balloon pump. The AngioJet (Possis Medical, Inc., Minneapolis, Minnesota) device is a catheter-based device for thrombus removal in which high-velocity saline jets are used to create a localized low-pressure zone at the distal catheter tip (Bernoulli effect), resulting in the maceration and removal of thrombus through an exhaust lumen. The use of rheolytic thrombectomy has been studied in thrombus-containing native coronary arteries as well as saphenous vein graft lesions. We report a case of a massive air embolus that occurred after activation of an AngioJet catheter in a thrombus-laden right coronary artery (RCA). The AngioJet catheter was then utilized to effectively aspirate the air embolus with restoration of coronary blood flow. Use of a guiding catheter that is nonocclusive or with side holes to ensure continuous blood flow from the central aorta may help avoid entrainment of air into the coronary artery during activation of the AngioJet thrombectomy catheter. To our knowledge, this is the first reported case of such a potential complication. In the event of such a complication, the AngioJet catheter can be implemented to aspirate a coronary air embolus. PMID:17620682

  17. Pulmonary Hypertension in Hemodialysis Patients Following Repeated Endovascular Thrombectomy

    PubMed Central

    Hsieh, Mu-Yang; Lin, Lin; Chen, Tsung-Yan; Wang, Ren-Huei; Huang, Su-Chin; Liu, HsiuChiao; Lai, Chao-Lun; Pu, Shih-Yen; Tsai, Kuei-Chin; Wu, Chih-Cheng

    2016-01-01

    Background The prevalence of pulmonary hypertension is unusually high in Taiwanese patients with end-stage renal disease. Thrombosis of hemodialysis grafts is common and pulmonary embolism has been reported after endovascular thrombectomy. The aim of this study was to evaluate the relationship between pulmonary hypertension and endovascular thrombectomy of hemodialysis grafts. Methods One hundred and ten patients on hemodialysis via arteriovenous grafts were enrolled in our study. The mean pulmonary artery pressure (PAP) was measured by right heart catheterization. Clinical information was collected by review of medical records. Comorbid cardiopulmonary disease was evaluated by echocardiography and chest X-ray. The history of patient vascular access thrombosis was reviewed from database, hemodialysis records, and interviews with staff at hemodialysis centers. Results Fifty-two participants (47%) had pulmonary hypertension diagnosed by right heart catheterization. There was no difference in the number of thrombectomy procedures between patients with and without pulmonary hypertension. Based on multivariate analysis, the number of prior endovascular thrombectomy procedures did not correlate with mean PAP (F-value = 1.10, p = 0.30) nor was it associated with pulmonary hypertension (odds ratio = 0.92, p = 0.17). Conclusions Prior endovascular arteriovenous graft thrombectomies were not associated with pulmonary hypertension or increased mean PAP in end-stage renal disease patients on maintenance hemodialysis. PMID:27274170

  18. Transoesophageal echocardiography reduces invasiveness of cavoatrial tumour thrombectomy

    PubMed Central

    Sobczyński, Robert; Mazur, Piotr; Chłosta, Piotr

    2014-01-01

    The traditional approach to cavoatrial thrombus excision requires median sternotomy, cardiopulmonary bypass with or without hypothermia and circulatory arrest and is associated with significant morbidity and mortality. We describe a transoesophageal echocardiography guided balloon catheter assisted technique for cavoatrial thrombectomy that avoids thoracotomy, extracorporeal circulation and circulatory arrest as an alternative to traditional methods. A 74-year-old man presented with a right solid renal mass confined to the kidney with thrombus extension through the right renal vein and the inferior vena cava into the right atrium. A right radical nephrectomy with cavoatrial thrombectomy under transoesophageal echocardiography guidance was successfully achieved using a balloon catheter-assisted technique with minimal intra-and postoperative morbidity. Cavoatrial tumour thrombectomy can be successfully performed without cardiopulmonary bypass, hypothermia and circulatory arrest. PMID:25337178

  19. AngioJet Thrombectomy for Occluded Dialysis Fistulae: Outcome Data

    SciTech Connect

    Littler, Peter Cullen, Nicola; Gould, Derek; Bakran, Ali; Powell, Steven

    2009-03-15

    This study evaluates AngioJet thrombectomy of occluded autogenous dialysis fistulae and polytetrafluoroethylene (PTFE) grafts in a UK hemodialysis population. Comparison is made with published data of alternative percutaneous thrombectomy methods. All patients with occluded dialysis fistulae who sought care at the Royal Liverpool University Hospital between October 2006 and June 2008 were included in the study. All patients were treated with the AngioJet Rheolytic Thrombectomy Device (Possis, Minneapolis, MN). Demographics, time of occlusion, adjunctive therapies, complications, and follow-up data have been prospectively recorded. A total of 64 thrombectomy procedures were performed in 48 patients. Forty-four autogenous fistulas were treated in 34 patients (19 brachiocephalic, 8 radiocephalic, and 7 transposed brachiobasilic). Twenty PTFE grafts were treated in 14 patients (9 brachioaxillary, 3 brachiocephalic loop grafts, 1 brachiobasilic, and 1 femoro-femoral). The average length of occlusion was 24 cm. Average time to intervention was 4 days. Immediate primary patency was 91%. Primary patency at 1, 3, and 6 months, respectively, was 71%, 60%, and 37%. Secondary patency at 3, 6, and 12 months was 87%, 77%, and 62%, respectively. Angioplasty was carried out in all procedures. Patients required stent insertion in 34 of the 64 thrombectomies to treat angioplasty-resistant stenoses. Complications included a puncture-site hematoma, and three angioplasty-related vein ruptures in one patient, all treated with covered stent grafts. Two cases of distal brachial arterial embolization were successfully treated by thrombosuction. AngioJet thrombectomy in dialysis access occlusion is safe and effective, comparing favorably with other methods.

  20. Safety and efficacy of thrombectomy in patients undergoing primary percutaneous coronary intervention for Acute ST elevation MI: A Meta-Analysis of Randomized Controlled Trials

    PubMed Central

    2010-01-01

    Background Clinical trials comparing thrombectomy devices with conventional percutaneous coronary interventions (PCI) in patients with acute ST elevation myocardial infarction (STEMI) have produced conflicting results. The objective of our study was to systematically evaluate currently available data comparing thrombectomy followed by PCI with conventional PCI alone in patients with acute STEMI. Methods Seventeen randomized trials (n = 3,909 patients) of thrombectomy versus PCI were included in this meta-analysis. We calculated the summary odds ratios for mortality, stroke, post procedural myocardial blush grade (MBG), thrombolysis in myocardial infarction (TIMI) grade flow, and post procedural ST segment resolution (STR) using random-effects and fixed-effects models. Results There was no difference in risk of 30-day mortality (44/1914 vs. 50/1907, OR 0.84, 95% CI 0.54-1.29, P = 0.42) among patients randomized to thrombectomy, compared with conventional PCI. Thrombectomy was associated with a significantly greater likelihood of TIMI 3 flow (1616/1826 vs. 1533/1806, OR 1.41, P = 0.007), MBG 3 (730/1526 vs. 486/1513, OR 2.42, P < 0.001), STR (923/1500 vs. 715/1494, OR 2.30, P < 0.001), and with a higher risk of stroke (14/1403 vs. 3/1413, OR 2.88, 95% CI 1.06-7.85, P = 0.04). Outcomes differed significantly between different device classes with a trend towards lower mortality with manual aspiration thrombectomy (MAT) (21/949 vs.36/953, OR 0.59, 95% CI 0.35-1.01, P = 0.05), whereas mechanical devices showed a trend towards higher mortality (20/416 vs.10/418, OR 2.07, 95% CI 0.95-4.48, P = 0.07). Conclusions Thrombectomy devices appear to improve markers of myocardial perfusion in patients undergoing primary PCI, with no difference in overall 30-day mortality but an increased likelihood of stroke. The clinical benefits of thrombectomy appear to be influenced by the device type with a trend towards survival benefit with MAT and worsening outcome with mechanical devices

  1. Stent Retriever-Based Thrombectomy in Octogenarians

    PubMed Central

    Cohen, Jose E.; Gomori, John M.; Leker, Ronen. R.

    2016-01-01

    Background and Aims Stent retriever-based thrombectomy (SRT) may be beneficial in patients with large hemispheric stroke. Previous studies concluded that favorable outcomes are far less frequent after endovascular therapy in older patients but have not explored outcomes in the era of newer-generation stent retrievers. Materials and Methods Consecutive patients with large hemispheric stroke treated with SRT were included. We compared neurological and functional outcomes between patients younger and older than 80. Results We included 16 patients older than 80 (22.5%, mean age 84.1 ± 4.4, 56% females) and compared them to 55 patients that were younger than 80 (77.5%, mean age 63.1 ± 12.5, 51% females). Risk factor profile, admission neurological severity, stroke etiology and procedure-related variables including excellent target vessel recanalization did not differ between the groups. Favorable outcome at 90 days (modified Rankin score ≤2) was more common in younger patients (77 vs. 23%; p = 0.031). In contrast, mortality rates were higher in octogenarians (40 vs. 7%; p = 0.01). Logistic regression analysis adjusting for neurological severity and collateral state identified age over 80 (odds ratio, OR 0.15, 95% CI 0.03–0.75; p = 0.02) and reperfusion state (OR 7.4, 95% CI 1.1–49.9; p = 0.04) as significant modifiers of favorable outcome. Similarly, age over 80 was identified as a positive predictor of mortality (OR 8.1, 95% CI 1.8–36.7; p = 0.007). Conclusions Octogenarians have higher chances of mortality and lower probability of achieving functional independence even after SRT. Nevertheless, because some elderly patients do achieve favorable outcomes, the cost-effectiveness of SRT in this population needs to be further studied. PMID:27781038

  2. A New Rotational Thrombectomy Catheter: System Design and First Clinical Experiences

    SciTech Connect

    Schmitt, Hans-Erich; Jaeger, Kurt A.; Jacob, Augustinus L.; Mohr, Helmuth; Labs, Karl-Heinz; Steinbrich, Wolfgang

    1999-11-15

    Purpose: To describe a new catheter for the percutaneous mechanical removal of fresh and organized thrombi, and to assess its efficacy and safety in vitro and in vivo. Methods: The catheter consists of a coated stainless steel spiral that rotates at 40,000 rpm over a guidewire inside the whole length of an 8 Fr, single-lumen, polyurethane catheter, driving a dual-blade cutting crown. Abraded occlusion material is sucked into the catheter head through distal side holes and transported by the spiral into a reservoir at the proximal end. The efficacy of the device was tested in arterial models and fresh bovine carotid arteries (n = 72). In a clinical pilot study 10 patients (8 women, 2 men; mean age 70.6 {+-} 10.1 years) with occlusions of the superficial femoral artery (2-12 cm, mean 5.8 cm), not older than 4 weeks, underwent thrombectomy with the new catheter. Results: In arterial models and bovine cadaver arteries the catheter completely removed fresh thrombi. Occlusion material of higher consistency was cut into particles of 100-500 {mu}m and transported outside. Thrombectomy was successful and vessel patency restored in all 10 patients. The ankle/brachial pressure index significantly (p < 0.0005) increased from 0.41 {+-} 0.18 before intervention to 0.88 {+-} 0.15 after 48 hr and to 0.84 {+-} 0.20 after 3 months. Two reocclusions occurred within 14 days after the intervention. Conclusion: Thrombectomy with the new device appears to be feasible and safe in patients with acute and subacute occlusions of the femoropopliteal artery.

  3. [Percutaneous rheolytic thrombectomy in the treatment of high-risk acute pulmonary embolism: Initial experience of a single center].

    PubMed

    Faria, Rita; Oliveira, Márcia; Ponte, Marta; Pires-Morais, Gustavo; Sousa, Marta; Fernandes, Paula; Rodrigues, Alberto; Braga, Pedro; Gonçalves, Manuel; Gama, Vasco

    2014-06-01

    For years, the treatment of high-risk pulmonary embolism (PE) was based on two well-defined strategies: thrombolysis, whose benefits have been documented in randomized trials, and surgical embolectomy. However, mechanical reperfusion by percutaneous techniques is used in an increasing number of patients, and is a valid therapeutic option when there is a formal contraindication to thrombolysis, as rescue therapy when thrombolysis fails to improve hemodynamics, and/or when emergency surgical thrombectomy is unavailable or contraindicated. This article discusses the indications for the use of percutaneous techniques in PE, reports the initial experience of our center with the AngioJet® thrombectomy device (Possis Medical Inc, Minneapolis, MN, USA) and reviews the available evidence, the most recent recommendations and the main complications associated with this procedure.

  4. Catheter-Directed Thrombolysis with Percutaneous Rheolytic Thrombectomy Versus Thrombolysis Alone in Upper and Lower Extremity Deep Vein Thrombosis

    SciTech Connect

    Kim, Hyun S. Patra, Ajanta; Paxton, Ben E.; Khan, Jawad; Streiff, Michael B.

    2006-12-15

    Purpose. To compare the efficacy of catheter-directed thrombolysis (CDT) alone versus CDT with rheolytic percutaneous mechanical thrombectomy (PMT) for upper and lower extremity deep vein thrombosis (DVT). Methods. A retrospective cohort of consecutive patients with acute iliofemoral or brachiosubclavian DVT treated with urokinase CDT was identified, and a chart review was conducted. Demographic characteristics, treatment duration, total lytic dose, clot lysis rates and complications were compared in patients treated with urokinase CDT alone or combined CDT and rheolytic PMT. Results. Forty limbs in 36 patients were treated with urokinase CDT alone. Twenty-seven limbs in 21 patients were treated with urokinase CDT and rheolytic PMT. The mean treatment duration for urokinase CDT alone was 48.0 {+-} 27.1 hr compared with 26.3 {+-} 16.6 hr for urokinase CDT and rheolytic PMT (p = 0.0004). The mean urokinase dose required for CDT alone was 5.6 {+-} 5.3 million units compared with 2.7 {+-} 1.8 million units for urokinase CDT with rheolytic PMT (p = 0.008). Complete clot lysis was achieved in 73% (29/40) of DVT treated with urokinase CDT alone compared with 82% (22/27) treated with urokinase CDT with rheolytic PMT. Conclusion. Percutaneous CDT with rheolytic PMT is as effective as CDT alone for acute proximal extremity DVT but requires significantly shorter treatment duration and lower lytic doses. Randomized studies to confirm the benefits of pharmacomechanical thrombolysis in the treatment of acute proximal extremity DVT are warranted.

  5. Combined mechanical loading of composite tubes

    NASA Technical Reports Server (NTRS)

    Derstine, Mark S.; Pindera, Marek-Jerzy; Bowles, David E.

    1988-01-01

    An analytical/experimental investigation was performed to study the effect of material nonlinearities on the response of composite tubes subjected to combined axial and torsional loading. The effect of residual stresses on subsequent mechanical response was included in the investigation. Experiments were performed on P75/934 graphite-epoxy tubes with a stacking sequence of (15/0/ + or - 10/0/ -15), using pure torsion and combined axial/torsional loading. In the presence of residual stresses, the analytical model predicted a reduction in the initial shear modulus. Experimentally, coupling between axial loading and shear strain was observed in laminated tubes under combined loading. The phenomenon was predicted by the nonlinear analytical model. The experimentally observed linear limit of the global shear response was found to correspond to the analytically predicted first ply failure. Further, the failure of the tubes was found to be path dependent above a critical load level.

  6. Early middle cerebral artery stenosis following stent-assisted thrombectomy

    PubMed Central

    Akpınar, Süha

    2015-01-01

    Stent-assisted thrombectomy (SAT) is an extensively used endovascular treatment method for stroke in which the thrombectomy stents come into direct contact with the vascular intimal surface and entrap the thrombus causing the arterial occlusion. Although there are a few studies that demonstrate that the vessel wall changes in the arteries where stroke intervention is performed, we observed progressive stenosis in early follow-up imaging studies in a case. We present a middle cerebral artery (MCA) stroke patient who had four repetitive stent passes during SAT and developed distal MCA stenosis 2 months after SAT at the control magnetic resonance angiography (MRA). Inclusion of early follow-up MRA studies would be helpful in defining the silent vascular changes in patients who have undergone repetitive SAT. PMID:26015531

  7. Delayed Presentation of Endovenous Heat-Induced Thrombosis Treated by Thrombolysis and Subsequent Open Thrombectomy

    PubMed Central

    Kwak, Jung Hak; Min, Sang Il; Kim, Song-Yi; Han, Ahram; Choi, Chanjoong; Ahn, Sanghyun; Ha, Jongwon; Min, Seung-Kee

    2016-01-01

    Although endovenous heat-induced thrombosis (EHIT) is frequently reported after endovenous laser ablation (EVLA), the incidence and timing of occurrence of EHIT are not fully understood. We present a case of EHIT successfully treated with a combination of surgical and endovascular treatments. A 57-year-old woman, two months post bilateral EVLA, presented with a swollen leg. Deep vein thrombosis was diagnosed by Doppler ultrasonography and computerized tomographic venography. We treated the patient with catheter-directed thrombolysis with urokinase after insertion of an inferior vena cava filter. After thrombolytic treatment, we performed surgical venous thrombectomy, due to the presence of a large thrombus in the femoral vein. During the operation, we found organized old thrombus at the great saphenous vein which connected to the deep femoral vein. From these findings, we confirmed the presence of EHIT despite a long time having passed after EVLA. The patient was placed on anticoagulation therapy with oral rivaroxaban for three months. PMID:27386456

  8. Combined hydrophobicity and mechanical durability through surface nanoengineering

    SciTech Connect

    Elliott, Paul R.; Stagon, Stephen P.; Huang, Hanchen; Furrer, David U.; Burlatsky, Sergei F.; Filburn, Thomas P.

    2015-04-08

    This paper reports combined hydrophobicity and mechanical durability through the nanoscale engineering of surfaces in the form of nanorod-polymer composites. Specifically, the hydrophobicity derives from nanoscale features of mechanically hard ZnO nanorods and the mechanical durability derives from the composite structure of a hard ZnO nanorod core and soft polymer shell. Experimental characterization correlates the morphology of the nanoengineered surfaces with the combined hydrophobicity and mechanical durability, and reveals the responsible mechanisms. Such surfaces may find use in applications, such as boat hulls, that benefit from hydrophobicity and require mechanical durability.

  9. Combined Hydrophobicity and Mechanical Durability through Surface Nanoengineering

    PubMed Central

    Elliott, Paul R.; Stagon, Stephen P.; Huang, Hanchen; Furrer, David U.; Burlatsky, Sergei F.; Filburn, Thomas P.

    2015-01-01

    This paper reports combined hydrophobicity and mechanical durability through the nanoscale engineering of surfaces in the form of nanorod-polymer composites. Specifically, the hydrophobicity derives from nanoscale features of mechanically hard ZnO nanorods and the mechanical durability derives from the composite structure of a hard ZnO nanorod core and soft polymer shell. Experimental characterization correlates the morphology of the nanoengineered surfaces with the combined hydrophobicity and mechanical durability, and reveals the responsible mechanisms. Such surfaces may find use in applications, such as boat hulls, that benefit from hydrophobicity and require mechanical durability. PMID:25851026

  10. Fascia Iliaca block as the sole anesthesia technique in a patient with recent myocardial infarction for emergency femoral thrombectomy

    PubMed Central

    Parate, Leena Harshad; Channappa, Nagaraj Mungasuvalli; Pujari, Vinayak; Iyer, Sadasivan

    2015-01-01

    Acute limb ischemia is a surgical emergency that precludes prolonged preoperative cardiac evaluation. A 70-year-old female with recent myocardial infarction was posted for emergency transfemoral thrombectomy. We discuss the perioperative anesthetic considerations in these case. Fascia iliaca block can be used as sole anesthesia technique for transfemoral thrombectomy in high-risk patients. PMID:25829911

  11. Catheter-directed thrombectomy and thrombolysis for symptomatic lower-extremity deep vein thrombosis: review of current interventional treatment strategies.

    PubMed

    Lin, Peter H; Ochoa, Lyssa N; Duffy, Patrick

    2010-09-01

    Deep vein thromboses (DVT) along with its clinical sequelae represent a major health care challenge in our society. An acute massive DVT can result in pulmonary embolism resulting in sudden death. Although oral or systemic anticoagulation therapy may minimize thrombus propagation, it remains ineffective in removing thrombus burden and consequently does not prevent postthrombotic syndrome. Recent advances in catheter-based interventions have led to the development of a variety of minimally invasive endovascular strategies to remove venous thrombi. These technologies use various principles, including catheter-directed thrombolytic infusion, rheolytic thrombectomy, mechanical fragmentation, or ultrasound energy to remove intraluminal thrombi. This article reviews the current advances in this technology and discusses the techniques of percutaneous treatment strategies of venous thrombotic conditions using various devices, including the AngioJet Power Pulse system, Trellis, and ultrasound-accelerated EkoSonic system. Finally, the authors' institutional experiences using these interventional treatment strategies in patients with acute and chronic DVT are discussed.

  12. Pulmonary Hypertension Among End-Stage Renal Failure Patients Following Hemodialysis Access Thrombectomy

    SciTech Connect

    Harp, Richard J.; Stavropoulos, S. William; Wasserstein, Alan G.; Clark, Timothy W.I.

    2005-01-15

    Purpose: Percutaneous hemodialysis thrombectomy causes subclinical pulmonary emboli without short-term clinical consequence; the long-term effects on the pulmonary arterial vasculature are unknown. We compared the prevalence of pulmonary hypertension between patients who underwent one or more hemodialysis access thrombectomy procedures with controls without prior thrombectomy.Methods: A retrospective case-control study was performed. Cases (n = 88) had undergone one or more hemodialysis graft thrombectomy procedures, with subsequent echocardiography during routine investigation of comorbid cardiovascular disease. Cases were compared with controls without end-stage renal disease (ESRD) (n = 100, group 1), and controls with ESRD but no prior thrombectomy procedures (n = 117, group 2). The presence and velocity of tricuspid regurgitation on echocardiography was used to determine the prevalence and grade of pulmonary hypertension; these were compared between cases and controls using the chi-square test and logistic regression.Results: The prevalence of pulmonary hypertension among cases was 52% (46/88), consisting of mild, moderate and severe in 26% (n = 23), 10% (n = 9) and 16% (n = 14), respectively. Prevalence of pulmonary hypertension among group 1 controls was 26% (26/100), consisting of mild, moderate and severe pulmonary hypertension in 14%, 5% and 7%, respectively. Cases had 2.7 times greater odds of having pulmonary hypertension than group 1 controls (p = 0.002). The prevalence of pulmonary hypertension among group 2 controls was 42% (49/117), consisting of mild, moderate and severe pulmonary arterial hypertension in 25% (n = 49), 10% (n = 12) and 4% (n = 5), respectively. Cases were slightly more likely to have pulmonary hypertension than group 2 controls (OR = 1.5), although this failed to reach statistical significance (p = 0.14).Conclusion: Prior hemodialysis access thrombectomy does not appear to be a risk factor for pulmonary arterial hypertension

  13. Increasing Efficacy of Thrombectomy by Using Digital Subtraction Angiography to Confirm Stent Retriever Clot Integration.

    PubMed

    Simon, Scott; Langan, Sara; Cooke, Jonathon

    2016-01-01

    Physicians performing thrombectomy for acute stroke have had increasing success as thrombectomy-specific devices have continued to evolve. As the devices evolve, so too must the techniques. The current generation of stent retriever thrombectomy devices requires five minutes of dwell time, regardless of the particularities of the case. We have noticed the presence of flow through the stent immediately prior to removal portends a lower chance of successful thrombus retrieval than when no flow is seen, regardless of dwell time. We hypothesize that interventionalists can use the presence or absence of flow to predict adequacy of seating time and decrease the number of deployments per case. This could significantly decrease time to recanalization by avoiding time-consuming, unsuccessful pulls. This is a technical report of a few cases of stent retriever thrombectomy. We propose using post-deployment digital subtraction angiography to confirm thrombus-device integration and increase the chance of thrombus removal. PMID:27182473

  14. Outcome and periprocedural time management in referred versus directly admitted stroke patients treated with thrombectomy

    PubMed Central

    Weber, Ralph; Reimann, Gernot; Weimar, Christian; Winkler, Angela; Berger, Klaus; Nordmeyer, Hannes; Hadisurya, Jeffrie; Brassel, Friedhelm; Kitzrow, Martin; Krogias, Christos; Weber, Werner; Busch, Elmar W.; Eyding, Jens

    2015-01-01

    Background: After thrombectomy has shown to be effective in acute stroke patients with large vessel occlusion, the potential benefit of secondary referral for such an intervention needs to be validated. Aims: We aimed to compare consecutive stoke patients directly admitted and treated with thrombectomy at a neurointerventional centre with patients secondarily referred for such a procedure from hospitals with a stroke unit. Methods: Periprocedure times and mortality in 300 patients primarily treated in eight neurointerventional centres were compared with 343 patients referred from nine other hospitals in a prospective multicentre study of a German neurovascular network. Data on functional outcome at 3 months was available in 430 (76.4%) patients. Results: In-hospital mortality (14.8% versus 11.7%, p = 0.26) and 3 months mortality (21.9% versus 24.1%, p = 0.53) were not statistically different in both patient groups despite a significant shorter symptom to groin puncture time in directly admitted patients, which was mainly caused by a longer interfacility transfer time. We found a nonsignificant trend for better functional outcome at 3 months in directly admitted patients (modified Rankin Scale 0–2, 44.0% versus 35.7%, p = 0.08). Conclusions: Our results show that a drip-and-ship thrombectomy concept can be effectively organized in a metropolitan stroke network. Every effort should be made to speed up the emergency interfacility transfer to a neurointerventional centre in stroke patients eligible for thrombectomy after initial brain imaging. PMID:27006695

  15. Elder homicide by unique combination of different mechanisms of asphyxia

    PubMed Central

    Pramanik, Parthasarathi

    2015-01-01

    Elder homicide is a fatal outcome of elder abuse and neglect. Multifactorial homicidal asphyxia in an elderly man by combination of three different mechanisms is an uncommon incident. This following case demonstrates a very unusual murder of 74-year-old man in his own residence. Crime scene visit and postmortem examination revealed that the victim was killed by combined effect of ligature strangulation, traumatic asphyxia and smothering by plastic bag. PMID:25664272

  16. Culprit lesion thrombus burden after manual thrombectomy or percutaneous coronary intervention-alone in ST-segment elevation myocardial infarction: the optical coherence tomography sub-study of the TOTAL (ThrOmbecTomy versus PCI ALone) trial

    PubMed Central

    Bhindi, Ravinay; Kajander, Olli A.; Jolly, Sanjit S.; Kassam, Saleem; Lavi, Shahar; Niemelä, Kari; Fung, Anthony; Cheema, Asim N.; Meeks, Brandi; Alexopoulos, Dimitrios; Kočka, Viktor; Cantor, Warren J.; Kaivosoja, Timo P.; Shestakovska, Olga; Gao, Peggy; Stankovic, Goran; Džavík, Vladimír; Sheth, Tej

    2016-01-01

    Aims Manual thrombectomy has been proposed as a strategy to reduce thrombus burden during primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI). However, the effectiveness of manual thrombectomy in reducing thrombus burden is uncertain. In this substudy of the TOTAL (ThrOmbecTomy versus PCI ALone) trial, we compared the thrombus burden at the culprit lesion using optical coherence tomography (OCT) in patients treated with thrombectomy vs. PCI-alone. Methods and results The TOTAL trial (N = 10 732) was an international, multicentre, randomized trial of thrombectomy (using the Export catheter, Medtronic Cardiovascular, Santa Rosa, CA, USA) in STEMI patients treated with primary PCI. The OCT sub-study prospectively enrolled 214 patients from 13 sites in 5 countries. Optical coherence tomography was performed immediately after thrombectomy or PCI-alone and then repeated after stent deployment. Thrombus quantification was performed by an independent core laboratory blinded to treatment assignment. The primary outcome of pre-stent thrombus burden as a percentage of segment analysed was 2.36% (95% CI: 1.73–3.22) in the thrombectomy group and 2.88% (95% CI: 2.12–3.90) in the PCI-alone group (P = 0.373). Absolute pre-stent thrombus volume was not different (2.99 vs. 3.74 mm3, P = 0.329). Other secondary outcomes of pre-stent quadrants of thrombus, post–stent atherothrombotic burden, and post-stent atherothrombotic volume were not different between groups. Conclusion Manual thrombectomy did not reduce pre-stent thrombus burden at the culprit lesion compared with PCI-alone. Both strategies were associated with low thrombus burden at the lesion site after the initial intervention to restore flow. PMID:25994742

  17. Behavior of cracked cylinders under combined thermal and mechanical loading

    SciTech Connect

    Ignaccolo, S.

    1996-12-01

    Nuclear pressure vessels and pipings can be submitted in their life to severe mechanical and thermal loadings. Engineering methods easy to apply, but sufficiently accurate, are needed to assess the flaws. In the field of non-linear fracture mechanics a lot of work has been achieved for structures submitted to mechanical loadings. But for thermal loadings, and particularly for thermal gradients, only few contributions are available. The authors propose, here, to present the main results of a complete set of finite element computations, conducted in France by CEA, EDF and FRAMATOME, on cracked cylinders submitted to combined mechanical and thermal loads. The interaction between these two types of loads is analyzed in the cases of austenitic and ferritic structures. Moreover, these results are compared to the predictions obtained by simplified engineering methods (R6 procedure, J{sub SA16}, and J{sub EDF} approaches). Their domain of validity is also discussed.

  18. Femoral and iliofemoral thrombectomy to prevent chronic venous insufficiency. Follow-up of 18 patients.

    PubMed

    de Araujo Bessa, J C

    1986-01-01

    Eighteen patients with femoral and iliofemoral venous thrombosis were treated surgically. Five of the patients had a moderate degree of venous congestion and were classified as having phlegmasia alba dolens and 13 patients had phlegmasia cerulea dolens. The mean age was 39 years, range 18-60 years; 6 were men and 12 women. Thrombectomy was performed with a Fogarty venous thrombectomy catheter. In all cases the thrombosis was verified by phlebography. Pre- and postoperative phlebography was used in all cases to show the patency of the femoral and iliofemoral segment. There was no operative pulmonary embolism or mortality. Heparin infusion was continued in the thrombectomized segment for 10 days followed by phenprocumone treatment. The patients were followed from 6 to 8 months, postoperatively. The operation was performed in the acute stage and the late results are as follows: 4 limbs good, 6 limbs fair and 8 limbs poor. The best results were obtained when the latency period was 24 to 72 hours. Postthrombotic sequelae could not be prevented in about 44% of all patients despite venous thrombectomy.

  19. Feasibility of Crosslinked Acrylic Shape Memory Polymer for a Thrombectomy Device

    PubMed Central

    Muschenborn, Andrea D.; Hearon, Keith; Volk, Brent L.; Conway, Jordan W.; Maitland, Duncan J.

    2014-01-01

    Purpose To evaluate the feasibility of utilizing a system of SMP acrylates for a thrombectomy device by determining an optimal crosslink density that provides both adequate recovery stress for blood clot removal and sufficient strain capacity to enable catheter delivery. Methods Four thermoset acrylic copolymers containing benzylmethacrylate (BzMA) and bisphenol A ethoxylate diacrylate (Mn~512, BPA) were designed with differing thermomechanical properties. Finite element analysis (FEA) was performed to ensure that the materials were able to undergo the strains imposed by crimping, and fabricated devices were subjected to force-monitored crimping, constrained recovery, and bench-top thrombectomy. Results Devices with 25 and 35 mole% BPA exhibited the highest recovery stress and the highest brittle response as they broke upon constrained recovery. On the contrary, the 15 mole % BPA devices endured all testing and their recovery stress (5 kPa) enabled successful bench-top thrombectomy in 2/3 times, compared to 0/3 for the devices with the lowest BPA content. Conclusion While the 15 mole% BPA devices provided the best trade-off between device integrity and performance, other SMP systems that offer recovery stresses above 5 kPa without increasing brittleness to the point of causing device failure would be more suitable for this application. PMID:25414549

  20. Gelled Complex Fluids: Combining Unique Structures with Mechanical Stability.

    PubMed

    Stubenrauch, Cosima; Gießelmann, Frank

    2016-03-01

    Gelled complex fluids are soft materials in which the microstructure of the complex fluid is combined with the mechanical stability of a gel. To obtain a gelled complex fluid one either adds a gelator to a complex fluid or replaces the solvent in a gel by a complex fluid. The most prominent example of a "natural" gelled complex fluid is the cell. There are various strategies by which one can form a gelled complex fluid; one such strategy is orthogonal self-assembly, that is, the independent but simultaneous formation of two coexisting self-assembled structures within one system. The aim of this Review is to describe the structure and potential applications of various man-made gelled complex fluids and to clarify whether or not the respective system is formed by orthogonal self-assembly.

  1. Performance of a thrombectomy device for aspiration of thrombus with various sizes based on a computational fluid dynamic modeling.

    PubMed

    Soleimani, Sajjad; Dubini, Gabriele; Pennati, Giancarlo

    2016-06-01

    It is important to thoroughly remove the thrombus within the course of aspiration thrombectomy; otherwise, it may lead to further embolization. The performance of the aspiration thrombectomy device with a generic geometry is studied through the computational approach. In order to model the thrombus aspiration, a real left coronary artery is chosen while thrombi with various sizes are located at the bifurcation area of the coronary artery and, depending on the size of the thrombus, it is stretched toward the side branches. The thrombus occupies the artery resembling the blood current obstruction in the coronary vessel similar to the situation that leads to heart attack. It is concluded that the aspiration ability of the thrombectomy device is not linked to the thrombus size; it is rather linked to the aspiration pressure and thrombus age (organized versus fresh thrombus). However, the aspiration time period correlates to the thrombus size. The minimum applicable aspiration pressure is also investigated in this study. PMID:26351782

  2. Apparent-Strain Correction for Combined Thermal and Mechanical Testing

    NASA Technical Reports Server (NTRS)

    Johnson, Theodore F.; O'Neil, Teresa L.

    2007-01-01

    Combined thermal and mechanical testing requires that the total strain be corrected for the coefficient of thermal expansion mismatch between the strain gage and the specimen or apparent strain when the temperature varies while a mechanical load is being applied. Collecting data for an apparent strain test becomes problematic as the specimen size increases. If the test specimen cannot be placed in a variable temperature test chamber to generate apparent strain data with no mechanical loads, coupons can be used to generate the required data. The coupons, however, must have the same strain gage type, coefficient of thermal expansion, and constraints as the specimen to be useful. Obtaining apparent-strain data at temperatures lower than -320 F is challenging due to the difficulty to maintain steady-state and uniform temperatures on a given specimen. Equations to correct for apparent strain in a real-time fashion and data from apparent-strain tests for composite and metallic specimens over a temperature range from -450 F to +250 F are presented in this paper. Three approaches to extrapolate apparent-strain data from -320 F to -430 F are presented and compared to the measured apparent-strain data. The first two approaches use a subset of the apparent-strain curves between -320 F and 100 F to extrapolate to -430 F, while the third approach extrapolates the apparent-strain curve over the temperature range of -320 F to +250 F to -430 F. The first two approaches are superior to the third approach but the use of either of the first two approaches is contingent upon the degree of non-linearity of the apparent-strain curve.

  3. Manual Aspiration Thrombectomy with Stent Placement: Rapid and Effective Treatment for Phlegmasia Cerulea Dolens with Impending Venous Gangrene

    SciTech Connect

    Oguzkurt, Levent Tercan, Fahri; Ozkan, Ugur

    2008-01-15

    Phlegmasia cerulea dolens is an uncommon but potentially life-threatening complication of acute deep vein thrombosis. It is an emergency and delay in treatment may cause death or loss of the patient's limb. Surgical thrombectomy is the recommended treatment in venous gangrene. Catheter-directed intrathrombus thrombolysis has been reported as successful, but it may require a lengthy infusion. Manual aspiration thrombectomy may clear the entire thrombus with no need for thrombolytic administration and provide rapid and effective treatment for patients with phlegmasia cerulea dolens with impending venous gangrene.

  4. Thrombectomy assisted by carotid stenting in acute ischemic stroke management: benefits and harms.

    PubMed

    Steglich-Arnholm, Henrik; Holtmannspötter, Markus; Kondziella, Daniel; Wagner, Aase; Stavngaard, Trine; Cronqvist, Mats E; Hansen, Klaus; Højgaard, Joan; Taudorf, Sarah; Krieger, Derk Wolfgang

    2015-12-01

    Extracranial carotid artery occlusion or high-grade stenosis with concomitant intracranial embolism causes severe ischemic stroke and shows poor response rates to intravenous thrombolysis (IVT). Endovascular therapy (EVT) utilizing thrombectomy assisted by carotid stenting was long considered risky because of procedural complexities and necessity of potent platelet inhibition-in particular following IVT. This study assesses the benefits and harms of thrombectomy assisted by carotid stenting and identifies factors associated with clinical outcome and procedural complications. Retrospective single-center analysis of 47 consecutive stroke patients with carotid occlusion or high-grade stenosis and concomitant intracranial embolus treated between September 2011 and December 2014. Benefits included early improvement of stroke severity (NIHSS ≥ 10) or complete remission within 72 h and favorable long-term outcome (mRS ≤ 2). Harms included complications during and following EVT. Mean age was 64.3 years (standard deviation ±12.5), 40 (85%) patients received IVT initially. Median NIHSS was 16 (inter-quartile range 14-19). Mean time from stroke onset to recanalization was 311 min (standard deviation ±78.0). Early clinical improvement was detected in 22 (46%) patients. Favorable outcome at 3 months occurred in 32 (68%) patients. Expedited patient management was associated with favorable clinical outcome. Two (4%) patients experienced symptomatic hemorrhage. Eight (17%) patients experienced stent thrombosis. Four (9%) patients died. Thrombectomy assisted by carotid stenting seems beneficial and reasonably safe with a promising rate of favorable outcome. Nevertheless, adverse events and complications call for additional clinical investigations prior to recommendation as clinical standard. Expeditious patient management is central to achieve good clinical outcome. PMID:26345413

  5. Atomistic insight into the catalytic mechanism of glycosyltransferases by combined quantum mechanics/molecular mechanics (QM/MM) methods.

    PubMed

    Tvaroška, Igor

    2015-02-11

    Glycosyltransferases catalyze the formation of glycosidic bonds by assisting the transfer of a sugar residue from donors to specific acceptor molecules. Although structural and kinetic data have provided insight into mechanistic strategies employed by these enzymes, molecular modeling studies are essential for the understanding of glycosyltransferase catalyzed reactions at the atomistic level. For such modeling, combined quantum mechanics/molecular mechanics (QM/MM) methods have emerged as crucial. These methods allow the modeling of enzymatic reactions by using quantum mechanical methods for the calculation of the electronic structure of the active site models and treating the remaining enzyme environment by faster molecular mechanics methods. Herein, the application of QM/MM methods to glycosyltransferase catalyzed reactions is reviewed, and the insight from modeling of glycosyl transfer into the mechanisms and transition states structures of both inverting and retaining glycosyltransferases are discussed.

  6. Combined quantum mechanics/molecular mechanics (QM/MM) methods in computational enzymology.

    PubMed

    van der Kamp, Marc W; Mulholland, Adrian J

    2013-04-23

    Computational enzymology is a rapidly maturing field that is increasingly integral to understanding mechanisms of enzyme-catalyzed reactions and their practical applications. Combined quantum mechanics/molecular mechanics (QM/MM) methods are important in this field. By treating the reacting species with a quantum mechanical method (i.e., a method that calculates the electronic structure of the active site) and including the enzyme environment with simpler molecular mechanical methods, enzyme reactions can be modeled. Here, we review QM/MM methods and their application to enzyme-catalyzed reactions to investigate fundamental and practical problems in enzymology. A range of QM/MM methods is available, from cheaper and more approximate methods, which can be used for molecular dynamics simulations, to highly accurate electronic structure methods. We discuss how modeling of reactions using such methods can provide detailed insight into enzyme mechanisms and illustrate this by reviewing some recent applications. We outline some practical considerations for such simulations. Further, we highlight applications that show how QM/MM methods can contribute to the practical development and application of enzymology, e.g., in the interpretation and prediction of the effects of mutagenesis and in drug and catalyst design.

  7. [Hemolytic thrombectomy and stenting of the superior mesenteric artery in acute mesenteric thrombosis (a clinical case report)].

    PubMed

    Shipovskiĭ, V N; Tsitsiashvili, M Sh; Khuan, Ch; Piliposian, E A

    2010-01-01

    Presented herein is a clinical case report concerning successful rheolytic thrombectomy (using the AngioJet catheter) followed by stenting and having yielded a good angiographic and clinical outcome in a female patient suffering from thrombosis of the superior mesenteric artery.

  8. Manual Aspiration Thrombectomy Using Penumbra Catheter in Patients with Acute M2 Occlusion : A Single-Center Analysis

    PubMed Central

    Park, Jung Soo

    2016-01-01

    Objective The efficacy and safety of manual aspiration thrombectomy using Penumbra in an acute occlusion of large intracranial arteries has been proven in many previous studies. Our study aimed to retrospectively assess the efficacy and safety of manual aspiration thrombectomy using Penumbra in patients with small vessel occlusions (M2 segment of the MCA). Methods We conducted a retrospective review of 32 patients who underwent manual aspiration thrombectomy using the Penumbra 4 MAX Reperfusion Catheter for treatment of an M2 occlusion between January 2013 and November 2014. We evaluated immediate angiographic results and clinical outcomes through review of patient electronic medical records. Results There were slightly more men in this study (M : F=18 : 14) and the median age was 72.5 (age range : 41–90). The rate of successful recanalization (TICI grade ≥2b) was 84% (27/32). NIHSS at discharge and favorable clinical outcomes at 3 months were significantly improved than baseline. Median initial NIHSS score was 10 (range : 4–25) and was 4 (range : 0–14) at discharge. Favorable clinical outcomes (mRS score ≤2 at 3 months) were seen in 25 out of 32 patients (78%). There were no procedure-related symptomatic intracerebral hemorrhages. One patient expired after discharge due to a cardiac problem. Conclusion Manual aspiration thrombectomy might be safe and is capable of achieving a high rate of successful recanalization and favorable clinical outcomes in patients with distal cerebral vessel occlusion (M2). PMID:27446515

  9. Treatment protocol based on assessment of clot quality during endovascular thrombectomy for acute ischemic stroke using the Trevo stent retriever.

    PubMed

    Ishikawa, Kojiro; Ohshima, Tomotaka; Nishihori, Masahiro; Imai, Tasuku; Goto, Shunsaku; Yamamoto, Taiki; Nishizawa, Toshihisa; Shimato, Shinji; Kato, Kyozo

    2016-08-01

    The optional endovascular approach for acute ischemic stroke is unclear. The Trevo stent retriever can be used as first-line treatment for fast mechanical recanalization. The authors developed a treatment protocol for acute ischemic stroke based on the assessment of clot quality during clot removal with the Trevo. This prospective single-center study included all patients admitted for acute ischemic stroke between July 2014 and February 2015, who underwent emergency endovascular treatment. According to the protocol, the Trevo was used for first-line treatment. Immediately after the Trevo was deployed, the stent delivery wire was pushed to open the stent by force (ACAPT technique). Clot quality was assessed on the basis of the perfusion status after deployment of the Trevo; continued occlusion or immediate reopening either reoccluded or maintained after the stent retriever had been in place for 5 min. If there was no obvious clot removal after the first pass with the Trevo, according to the quality of the clot, either a second pass was performed or another endovascular device was selected. Twelve consecutive patients with acute major cerebral artery occlusion were analyzed. Thrombolysis in cerebral infarction score 2b and 3 was achieved in 11 patients (91.7%) and 9 (75%) had a good clinical outcome after 90 days based on a modified Rankin scale score ≤ 2. Symptomatic intracranial hemorrhage occurred in 1 patient (8.3%). The overall mortality rate was 8.3%. Endovascular thrombectomy using the Trevo stent retriever for first-line treatment is feasible and effective. PMID:27578909

  10. Treatment protocol based on assessment of clot quality during endovascular thrombectomy for acute ischemic stroke using the Trevo stent retriever

    PubMed Central

    Ishikawa, Kojiro; Ohshima, Tomotaka; Nishihori, Masahiro; Imai, Tasuku; Goto, Shunsaku; Yamamoto, Taiki; Nishizawa, Toshihisa; Shimato, Shinji; Kato, Kyozo

    2016-01-01

    ABSTRACT The optional endovascular approach for acute ischemic stroke is unclear. The Trevo stent retriever can be used as first-line treatment for fast mechanical recanalization. The authors developed a treatment protocol for acute ischemic stroke based on the assessment of clot quality during clot removal with the Trevo. This prospective single-center study included all patients admitted for acute ischemic stroke between July 2014 and February 2015, who underwent emergency endovascular treatment. According to the protocol, the Trevo was used for first-line treatment. Immediately after the Trevo was deployed, the stent delivery wire was pushed to open the stent by force (ACAPT technique). Clot quality was assessed on the basis of the perfusion status after deployment of the Trevo; continued occlusion or immediate reopening either reoccluded or maintained after the stent retriever had been in place for 5 min. If there was no obvious clot removal after the first pass with the Trevo, according to the quality of the clot, either a second pass was performed or another endovascular device was selected. Twelve consecutive patients with acute major cerebral artery occlusion were analyzed. Thrombolysis in cerebral infarction score 2b and 3 was achieved in 11 patients (91.7%) and 9 (75%) had a good clinical outcome after 90 days based on a modified Rankin scale score ≤ 2. Symptomatic intracranial hemorrhage occurred in 1 patient (8.3%). The overall mortality rate was 8.3%. Endovascular thrombectomy using the Trevo stent retriever for first-line treatment is feasible and effective. PMID:27578909

  11. Soluble collagen approach to a combination tannage mechanism

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although complex salts of Cr(III) sulfate are currently the most effective tanning agents, salts of other metals, including aluminum, have been used either alone or in combination with vegetable tannins or other organic chemicals. In the present study, the interactions of aluminum sulfate, and quebr...

  12. Soluble collagen approach to a combination tannage mechanism

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although complex salts of Cr(III) sulfate are currently the most effective tanning agents, salts of other metals, including aluminum, have been used either alone or in combination with vegetable tannins or other organic chemicals. In the present study, the interactions of metallic sulfates, and cond...

  13. Thrombosis in ST-elevation myocardial infarction: Insights from thrombi retrieved by aspiration thrombectomy

    PubMed Central

    Ribeiro, Daniel Rios P; Cambruzzi, Eduardo; Schmidt, Marcia Moura; Quadros, Alexandre S

    2016-01-01

    In patients with ST-elevation myocardial infarction, recurrent cardiovascular events still remain the main cause of morbidity and mortality, despite significant improvements in antithrombotic therapy. We sought to review data regarding coronary thrombus analysis provided by studies using manual aspiration thrombectomy (AT), and to discuss how insights from this line of investigation could further improve management of acute coronary disease. Several studies investigated the fresh specimens retrieved by AT using techniques such as traditional morphological evaluation, optical microscopy, scanning electron microscopy, magnetic resonance imaging, and immunohistochemistry. These approaches have provided a better understanding of the composition and dynamics of the human coronary thrombosis process, as well as its relationship with some clinical outcomes. Recent data signaling to new antithrombotic therapeutic targets are still emerging. PMID:27354893

  14. Laparoscopic radical nephrectomy with inferior vena cava thrombectomy: highlight of key surgical steps

    PubMed Central

    Sim, A.; Todenhöfer, T.; Mischinger, J.; Fahmy, O.; Boettge, J.; Rausch, S.; Bier, S.; Aufderklamm, S.; Stenzl, A.; Gakis, G.; Schwentner, C.

    2016-01-01

    ABSTRACT Objective: Vascular involvement in the form of renal vein (RV) or inferior vena cava (IVC) thrombus can be seen in 4-10% of patients presented with RCC. In patients without presence of metastasis, surgical treatment in the form of radical nephrectomy remains the treatment of choice with 5-year survival rates of 45-70%. Open surgery is still the first treatment option of choice at the moment for RCC patients with IVC thrombus. Materials and Methods: In our study, we are reporting a case of patient with RCC and level I IVC thrombus treated with laparoscopy. Our patient is a 72 years old man with underlying co-morbidity of hypertension and chronic kidney disease (CKD) presented with right-sided RCC. The CT scan done showed a large right renal upper pole tumor measuring 8.4x5.2cm with level I IVC thrombus (Figure-1). There were no regional lymphadenopathy and the staging scans were negative. Results: The operative time was 124 minutes and blood loss was minimal. The patient was progressed to diet on POD 1 with bowel movement on POD 2. There was no significant change in the pre and post-operative glomerular filtration rate (GFR). The surgical drain was removed on POD2. The patient was discharged well on POD 5. There were no perioperative complications. The pathology was pT3bN0M0 Fuhrman grade II clear cell RCC. Conclusions: As a conclusion, laparoscopic radical nephrectomy and IVC thrombectomy is a complex and technically demanding surgery. With advancement of surgical skills as well as technology, more cases of minimally invasive laparoscopic radical nephrectomy and IVC thrombectomy can performed to improve the perioperative outcomes of carefully selected patients in a high volume center. PMID:27564306

  15. Connecting caddisworm silk structure and mechanical properties: combined infrared spectroscopy and mechanical analysis

    PubMed Central

    Ashton, Nicholas N.; Pan, Huaizhong; Stewart, Russell J.

    2016-01-01

    The underwater silk of an aquatic casemaking caddisfly larvae (Hesperophylax occidentalis) is viscoelastic, and displays distinct yield behaviour, large strain cycle hysteresis and near complete recovery of its initial strength and stiffness when unloaded. Yield followed by a stress plateau has been attributed to sequential rupture of serial Ca2+-cross-linked phosphoserine (pS) β-domains. Spontaneous recovery has been attributed to refolding of the Ca2+/pS domains powered by an elastic network. In this study, native Ca2+ ions were exchanged with other metal ions, followed by combined mechanical and FTIR analysis to probe the contribution of pS/metal ion complexes to silk mechanical properties. After exchange of Ca2+ with Na+, the fibres are soft elastomers and the infrared spectra are consistent with Cv3 symmetry of the – groups. Multivalent metal ions decreased the – symmetry and the symmetric stretching modes (vs) split in a manner characteristic of ordered phosphate compounds, such as phosphate minerals and lamellar bilayers of phosphatidic acid lipids. Integrated intensities of the vs bands, indicative of the metal ion's effect on transition dipole moment of the P–O bonds, and thereby the strength of the phosphate metal complex, increased in the order: Na+ < Mg2+ < Sr2+ < Ba2+ < Ca2+ < Eu3+ < La3+ < Zn2+ < Fe2+. With a subset of the metal ion series, the initial stiffness and yield stress of metal ion-exchanged fibres increased in the same order: establishing the link between phosphate transition dipole moments and silk fibre strength. PMID:27278649

  16. Connecting caddisworm silk structure and mechanical properties: combined infrared spectroscopy and mechanical analysis.

    PubMed

    Ashton, Nicholas N; Pan, Huaizhong; Stewart, Russell J

    2016-06-01

    The underwater silk of an aquatic casemaking caddisfly larvae (Hesperophylax occidentalis) is viscoelastic, and displays distinct yield behaviour, large strain cycle hysteresis and near complete recovery of its initial strength and stiffness when unloaded. Yield followed by a stress plateau has been attributed to sequential rupture of serial Ca(2+)-cross-linked phosphoserine (pS) β-domains. Spontaneous recovery has been attributed to refolding of the Ca(2+)/pS domains powered by an elastic network. In this study, native Ca(2+) ions were exchanged with other metal ions, followed by combined mechanical and FTIR analysis to probe the contribution of pS/metal ion complexes to silk mechanical properties. After exchange of Ca(2+) with Na(+), the fibres are soft elastomers and the infrared spectra are consistent with Cv3 symmetry of the -[Formula: see text] groups. Multivalent metal ions decreased the -[Formula: see text] symmetry and the symmetric stretching modes (vs) split in a manner characteristic of ordered phosphate compounds, such as phosphate minerals and lamellar bilayers of phosphatidic acid lipids. Integrated intensities of the vs bands, indicative of the metal ion's effect on transition dipole moment of the P-O bonds, and thereby the strength of the phosphate metal complex, increased in the order: Na(+) < Mg(2+) < Sr(2+) < Ba(2+) < Ca(2+) < Eu(3+) < La(3+) < Zn(2+) < Fe(2+) With a subset of the metal ion series, the initial stiffness and yield stress of metal ion-exchanged fibres increased in the same order: [Formula: see text] [Formula: see text] establishing the link between phosphate transition dipole moments and silk fibre strength. PMID:27278649

  17. Combined holographic-mechanical optical tweezers: Construction, optimization, and calibration

    SciTech Connect

    Hanes, Richard D. L.; Jenkins, Matthew C.; Egelhaaf, Stefan U.

    2009-08-15

    A spatial light modulator (SLM) and a pair of galvanometer-mounted mirrors (GMM) were combined into an optical tweezers setup. This provides great flexibility as the SLM creates an array of traps, which can be moved smoothly and quickly with the GMM. To optimize performance, the effect of the incidence angle on the SLM with respect to phase and intensity response was investigated. Although it is common to use the SLM at an incidence angle of 45 deg., smaller angles give a full 2{pi} phase shift and an output intensity which is less dependent on the magnitude of the phase shift. The traps were calibrated using an active oscillatory technique and a passive probability distribution method.

  18. Combined holographic-mechanical optical tweezers: construction, optimization, and calibration.

    PubMed

    Hanes, Richard D L; Jenkins, Matthew C; Egelhaaf, Stefan U

    2009-08-01

    A spatial light modulator (SLM) and a pair of galvanometer-mounted mirrors (GMM) were combined into an optical tweezers setup. This provides great flexibility as the SLM creates an array of traps, which can be moved smoothly and quickly with the GMM. To optimize performance, the effect of the incidence angle on the SLM with respect to phase and intensity response was investigated. Although it is common to use the SLM at an incidence angle of 45 degrees, smaller angles give a full 2pi phase shift and an output intensity which is less dependent on the magnitude of the phase shift. The traps were calibrated using an active oscillatory technique and a passive probability distribution method. PMID:19725658

  19. Combining two proven mechanical tenderness measurements in one steak.

    PubMed

    Callahan, Z D; Belk, K E; Miller, R K; Morgan, J B; Lorenzen, C L

    2013-09-01

    This research was performed to determine the true efficacy of measuring both Warner-Bratzler shear force (WBSF) and slice shear force (SSF) in the same steak. The objectives were to compare cooking methods commonly used in preparing steaks for WBSF and SSF procedures and compare them at different cooling times. United States Department of Agriculture select strip loins (n = 240) were aged for either 7 or 14 d to increase the variation in tenderness. Each strip loin was then frozen and cut into 2.54-cm steaks. Steaks were then cooked to an internal temperature of 71°C using a convection conveyor oven (conveyor), a convection oven, clamshell grill, or an open hearth grill. Steaks were allotted to 4 different cooling times to create the combinations of: WBSF 4 h/SSF 0 h, WBSF 4 h/SSF 4 h, WBSF 24 h/SSF 0 h, WBSF 24 h/SSF 24 h. Five 1.25-cm cores were used for WBSF and one 1- by 5-cm slice for SSF. The WBSF from steaks cooked with conveyor were tougher than convection oven cooked steaks [51.9 Newtons (N) vs. 46.1 N; P < 0.05]. However, SSF were tougher when cooked in oven compared with those cooked in conveyor (267.5 N vs. 237.2 N; P < 0.05). Correlations for WBSF and SSF performed in the same steak ranged from 0.51 to 0.88 (P < 0.0001). The WBSF 24 h/SSF 0 h and WBSF 4 h/SSF 4 h had the strongest relationships (0.88 and 0.82, respectively; P < 0.05) between WBSF and SSF when using clamshell method. Performing WBSF and SSF in the same steak was successful based on moderate to high correlation values but the magnitude of the relationship is dependent on the combination of cooking method and cooling time.

  20. Aortic arch thrombectomy in a 2.8 kilogram neonate--a case report and review of the literature.

    PubMed

    Omeje, Ikenna; Ram, Awat; Kostolny, Martin

    2013-02-01

    Aortic arch thrombus is a rare occurrence in neonates. In the few described cases, this has mainly been associated with sepsis or early postnatal interventions, such as insertion of umbilical arterial line. We describe a case of occlusive aortic arch thrombus in a neonate who presented with signs of critical coarctation and successfully underwent surgical thrombectomy on deep hypothermic circulatory arrest. We also present a review of the most recently published cases of aortic arch thrombus in neonates and the treatment options employed.

  1. Treating electrostatics with Wolf summation in combined quantum mechanical and molecular mechanical simulations

    SciTech Connect

    Ojeda-May, Pedro; Pu, Jingzhi

    2015-11-07

    The Wolf summation approach [D. Wolf et al., J. Chem. Phys. 110, 8254 (1999)], in the damped shifted force (DSF) formalism [C. J. Fennell and J. D. Gezelter, J. Chem. Phys. 124, 234104 (2006)], is extended for treating electrostatics in combined quantum mechanical and molecular mechanical (QM/MM) molecular dynamics simulations. In this development, we split the QM/MM electrostatic potential energy function into the conventional Coulomb r{sup −1} term and a term that contains the DSF contribution. The former is handled by the standard machinery of cutoff-based QM/MM simulations whereas the latter is incorporated into the QM/MM interaction Hamiltonian as a Fock matrix correction. We tested the resulting QM/MM-DSF method for two solution-phase reactions, i.e., the association of ammonium and chloride ions and a symmetric SN{sub 2} reaction in which a methyl group is exchanged between two chloride ions. The performance of the QM/MM-DSF method was assessed by comparing the potential of mean force (PMF) profiles with those from the QM/MM-Ewald and QM/MM-isotropic periodic sum (IPS) methods, both of which include long-range electrostatics explicitly. For ion association, the QM/MM-DSF method successfully eliminates the artificial free energy drift observed in the QM/MM-Cutoff simulations, in a remarkable agreement with the two long-range-containing methods. For the SN{sub 2} reaction, the free energy of activation obtained by the QM/MM-DSF method agrees well with both the QM/MM-Ewald and QM/MM-IPS results. The latter, however, requires a greater cutoff distance than QM/MM-DSF for a proper convergence of the PMF. Avoiding time-consuming lattice summation, the QM/MM-DSF method yields a 55% reduction in computational cost compared with the QM/MM-Ewald method. These results suggest that, in addition to QM/MM-IPS, the QM/MM-DSF method may serve as another efficient and accurate alternative to QM/MM-Ewald for treating electrostatics in condensed-phase simulations of chemical

  2. Treating electrostatics with Wolf summation in combined quantum mechanical and molecular mechanical simulations

    NASA Astrophysics Data System (ADS)

    Ojeda-May, Pedro; Pu, Jingzhi

    2015-11-01

    The Wolf summation approach [D. Wolf et al., J. Chem. Phys. 110, 8254 (1999)], in the damped shifted force (DSF) formalism [C. J. Fennell and J. D. Gezelter, J. Chem. Phys. 124, 234104 (2006)], is extended for treating electrostatics in combined quantum mechanical and molecular mechanical (QM/MM) molecular dynamics simulations. In this development, we split the QM/MM electrostatic potential energy function into the conventional Coulomb r-1 term and a term that contains the DSF contribution. The former is handled by the standard machinery of cutoff-based QM/MM simulations whereas the latter is incorporated into the QM/MM interaction Hamiltonian as a Fock matrix correction. We tested the resulting QM/MM-DSF method for two solution-phase reactions, i.e., the association of ammonium and chloride ions and a symmetric SN2 reaction in which a methyl group is exchanged between two chloride ions. The performance of the QM/MM-DSF method was assessed by comparing the potential of mean force (PMF) profiles with those from the QM/MM-Ewald and QM/MM-isotropic periodic sum (IPS) methods, both of which include long-range electrostatics explicitly. For ion association, the QM/MM-DSF method successfully eliminates the artificial free energy drift observed in the QM/MM-Cutoff simulations, in a remarkable agreement with the two long-range-containing methods. For the SN2 reaction, the free energy of activation obtained by the QM/MM-DSF method agrees well with both the QM/MM-Ewald and QM/MM-IPS results. The latter, however, requires a greater cutoff distance than QM/MM-DSF for a proper convergence of the PMF. Avoiding time-consuming lattice summation, the QM/MM-DSF method yields a 55% reduction in computational cost compared with the QM/MM-Ewald method. These results suggest that, in addition to QM/MM-IPS, the QM/MM-DSF method may serve as another efficient and accurate alternative to QM/MM-Ewald for treating electrostatics in condensed-phase simulations of chemical reactions.

  3. Unexpected Rupture of a Giant Lobulated Thrombotic Middle Cerebral Artery Aneurysm and Emergency Surgical Treatment With Thrombectomy: A Case Report and Review of the Literature

    PubMed Central

    Koksal, Vaner; Kayaci, Selim

    2016-01-01

    Introduction The treatment of giant intracranial aneurysms is one of the most challenging cerebrovascular problems of neurosurgery. We report the rupture of a giant, lobulated, and almost completely thrombosed middle cerebral artery (MCA) aneurysm that is the ninth such report in the literature. We also investigated additional solutions used in the treatment of this patient. Case Presentation A 58-year-old man had been admitted with headache 8 years previously (in 2005), and a giant MCA aneurysm was detected. Two separate endovascular interventions were performed, and both failed. The patient began to live with the giant aneurysm. As there was a large thrombosis filling the aneurysm lumen during the previous endovascular procedures, the aneurysm was not expected to rupture. However, a rupture eventually occurred, in 2013. Even if an aneurysm is very large, lobulated, old, and almost completely thrombosed, it can suddenly bleed. During surgery on this patient, we observed severe cerebral vasospasm caused by a giant thrombosed aneurysmal rupture. Despite the complications, surgery is a life-saving treatment for this emergency when other strategies are not possible. Thrombectomy and clipping are approaches that require a great deal of courage for the neurosurgeon, in terms of entering the risky area within the aneurysm. Conclusions We believe that it would be more appropriate to plan for combined treatment with surgical and endovascular approaches before the emergency condition could occur. PMID:27781115

  4. An application of a combined gradient system to stabilize a mechanical system

    NASA Astrophysics Data System (ADS)

    Chen, Xiang-Wei; Zhang, Ye; Mei, Feng-Xiang

    2016-10-01

    A gradient system and a skew-gradient system can be merged into a combined gradient system. The differential equations of the combined gradient system are established and its property is studied. If a mechanical system can be represented as a combined gradient system, the stability of the mechanical system can be studied by using the property of the combined gradient system. Some examples are given to illustrate the applications of the results. Project supported by the National Natural Science Foundation of China (Grant Nos. 11372169 and 11272050).

  5. Resizing procedure for optimum design of structures under combined mechanical and thermal loading

    NASA Technical Reports Server (NTRS)

    Adelman, H. M.; Narayanaswami, R.

    1976-01-01

    An algorithm is reported for resizing structures subjected to combined thermal and mechanical loading. The algorithm is applicable to uniaxial stress elements (rods) and membrane biaxial stress members. Thermal Fully Stressed Design (TFSD) is based on the basic difference between mechanical and thermal stresses in their response to resizing. The TFSD technique is found to converge in fewer iterations than ordinary fully stressed design for problems where thermal stresses are comparable to the mechanical stresses. The improved convergence is demonstrated by example with a study of a simplified wing structure, built-up with rods and membranes and subjected to a combination of mechanical loads and a three dimensional temperature distribution.

  6. Percutaneous Aspiration Thrombectomy for the Treatment of Arterial Thromboembolic Occlusions Following Percutaneous Transluminal Angioplasty

    SciTech Connect

    Schleder, Stephan; Diekmann, Matthias; Manke, Christoph; Heiss, Peter

    2015-02-15

    PurposeThis study was designed to evaluate the technical success and the early clinical outcome of patients undergoing percutaneous aspiration thrombectomy (PAT) for the treatment of arterial thromboembolism following percutaneous infrainguinal transluminal angioplasty (PTA).MethodsIn this single-center study, during a period of 7 years retrospectively, 47 patients (22 male, 47 %) with a mean age of 73 (range 53–96) years were identified in whom PAT was performed for the treatment of thromboembolic complications of infrainguinal PTA. Primary technical success was defined as residual stenosis of <50 % in diameter after sole PAT, whereas secondary technical success was defined as residual stenosis of <50 % in diameter after PAT and additional PTA and/or stenting. Clinical outcome parameters (e.g., need for further intervention, minor/major amputation) were evaluated for the 30-day postinterventional period.ResultsPrimary technical success was achieved in 64 % of patients (30/47); secondary technical success was obtained in 96 % of patients (45/47). Clinical outcome data were available in 38 patients. In 87 % of patients (33/38), there was no need for further intervention within the 30-day postinterventional period. In three patients, minor amputations were conducted due to preexisting ulcerations (Rutherford Category 5 respectively).ConclusionsPAT enables endovascular treatment of iatrogenic thromboembolic complications after PTA with good technical and early clinical results and minimal morbidity.

  7. In Vitro Evaluation of a New Rotational Thrombectomy Device: The Straub Rotarex Catheter

    SciTech Connect

    Zana, Katalin; Otal, Philippe; Fornet, Bela; Forrai, Gabor; Chabbert, Valerie; Smayra, Tarek; Joffre, Francis; Rousseau, Herve

    2001-09-15

    Purpose: To evaluate the efficacy of a new rotational thrombectomy device, and the procedure-related risk of particle embolization.Methods: The experiments were performed in transparent silicone tubes. The conditions of flow were as close as possible to physiological parameters. Distal embolization was detected by a mesh of nylon filters.Results: The Straub Rotarex catheter was able to remove all clots. The mean number of migrating particles larger than 1000 {mu}m was 0.17 ({+-}0.38), the mean number of 400-1000 {mu}m migrating particles was 1.08 ({+-}1.04). The mean intervention time was 67 ({+-}37) sec. The mean volume of collected liquid was 96.6 ({+-}24.7) ml.Conclusion: The in vitro results suggest that the Straub Rotarex catheter is able to remove large volumes of thrombus with a limited risk of embolization. The main limitation of our model is the absence of adhesion of the clot to the tube.

  8. Use of the GuideLiner catheter for aspiration thrombectomy in a patient with ST-elevation myocardial infarction with a large intracoronary thrombus.

    PubMed

    Numasawa, Yohei; Motoda, Hiroyuki; Yamazaki, Hiroyuki; Kuno, Toshiki; Kodaira, Masaki; Fujisawa, Taishi

    2016-04-01

    We report a 67-year-old man with ST-elevation myocardial infarction with a large intracoronary thrombus who was successfully treated with percutaneous thrombectomy using the GuideLiner catheter. This catheter is designed for the "Mother and Child" technique with a rapid exchange system and it has a larger internal diameter than conventional aspiration devices. When aspiration thrombectomy using a conventional aspiration catheter is not feasible or fails, use of the GuideLiner catheter for aspiration of thrombus is a reasonable alternative for primary percutaneous coronary intervention in patients with acute myocardial infarction.

  9. Aspiration thrombectomy in a case of acute myocardial infarction due to coronary emboli in a patient with peripartum cardiomyopathy and mural thrombus.

    PubMed

    Abdulbaki, Abdulrahman; Kocherla, Cyrus; Modi, Kalgi

    2015-01-01

    Acute coronary syndrome (ACS) due to embolic phenomenon in the setting of peripartum cardiomyopathy (PPCM) and left ventricular mural thrombus is a rare occurrence. There have been two known cases described in medical literature. We present a unique case in which catheter-based aspiration thrombectomy was used to successfully treat a patient with ACS due to coronary emboli in the setting of PPCMand left ventricular mural thrombus. We believe this to be the first report of the use of aspiration thrombectomy in such a clinical case.

  10. Anesthetic management of right atrial mass removal and pulmonary artery thrombectomy in a patient with primary antiphospholipid antibody syndrome.

    PubMed

    Rawat, S K S; Mehta, Yatin; Vats, Mayank; Mishra, Yugal; Khurana, Poonam; Trehan, Naresh

    2010-01-01

    Antiphospholipid antibody syndrome (APLAS) characterises a clinical condition of arterial and venous thrombosis associated with phospholipids directed antibodies. APLAS occurs in 2% of the general population. However, one study demonstrated that 7.1% of hospitalised patients were tested positive for at least one of the three anticardiolipin antibody idiotype. Antiphospholipid antibodies often inhibit phospholipids dependent coagulation in vitro and interfere with laboratory testing of hemostasis. Therefore, the management of anticoagulation during cardiopulmonary bypass can be quite challenging in these patients. Here, we present a case of right atrial mass removal and pulmonary thrombectomy in a patient of APLAS. PMID:20075534

  11. Interpretation of nuclear resonant vibrational spectra of rubredoxin using a combined quantum mechanics and molecular mechanics approach.

    PubMed

    Paulsen, Hauke; Trautwein, Alfred X; Wegner, Patrick; Schmidt, Christian; Chumakov, Aleksandr I; Schünemann, Volker

    2011-12-01

    Nuclear resonant vibrational spectra of the reduced and oxidized form of a mutant of rubredoxin from Pyrococcus abyssii were measured and are compared with simulated spectra that were calculated by a combined quantum mechanics (QM) and molecular mechanics (MM) method. Density functional theory was used for the QM level. Calculations were performed for different models of rubredoxin. Realistic spectra were simulated with reduced models that include at least the iron center, the four cysteins coordinating it, and the residues connected to the cysteins together with a QM layer that comprises the first two coordination shells of the iron center. Larger QM layers did not lead to significant changes of the simulated spectra.

  12. Excited States and Photochemistry of Chromophores in the Photoactive Proteins Explored by the Combined Quantum Mechanical and Molecular Mechanical Calculations.

    PubMed

    Liu, Lihong; Cui, Ganglong; Fang, Wei-Hai

    2015-01-01

    A photoactive protein usually contains a unique chromophore that is responsible for the initial photoresponse and functions of the photoactive protein are determined by the interaction between the chromophore and its protein surroundings. The combined quantum mechanical and molecular mechanical (QM/MM) approach is demonstrated to be a very useful tool for exploring structures and functions of a photoactive protein with the chromophore and its protein surroundings treated by the QM and MM methods, respectively. In this review, we summarize the basic formulas of the QM/MM approach and emphasize its applications to excited states and photoreactions of chromophores in rhodopsin protein, photoactive yellow protein, and green fluorescent protein. PMID:26415847

  13. Conical intersections in solution: Formulation, algorithm, and implementation with combined quantum mechanics/molecular mechanics method

    NASA Astrophysics Data System (ADS)

    Cui, Ganglong; Yang, Weitao

    2011-05-01

    The significance of conical intersections in photophysics, photochemistry, and photodissociation of polyatomic molecules in gas phase has been demonstrated by numerous experimental and theoretical studies. Optimization of conical intersections of small- and medium-size molecules in gas phase has currently become a routine optimization process, as it has been implemented in many electronic structure packages. However, optimization of conical intersections of small- and medium-size molecules in solution or macromolecules remains inefficient, even poorly defined, due to large number of degrees of freedom and costly evaluations of gradient difference and nonadiabatic coupling vectors. In this work, based on the sequential quantum mechanics and molecular mechanics (QM/MM) and QM/MM-minimum free energy path methods, we have designed two conical intersection optimization methods for small- and medium-size molecules in solution or macromolecules. The first one is sequential QM conical intersection optimization and MM minimization for potential energy surfaces; the second one is sequential QM conical intersection optimization and MM sampling for potential of mean force surfaces, i.e., free energy surfaces. In such methods, the region where electronic structures change remarkably is placed into the QM subsystem, while the rest of the system is placed into the MM subsystem; thus, dimensionalities of gradient difference and nonadiabatic coupling vectors are decreased due to the relatively small QM subsystem. Furthermore, in comparison with the concurrent optimization scheme, sequential QM conical intersection optimization and MM minimization or sampling reduce the number of evaluations of gradient difference and nonadiabatic coupling vectors because these vectors need to be calculated only when the QM subsystem moves, independent of the MM minimization or sampling. Taken together, costly evaluations of gradient difference and nonadiabatic coupling vectors in solution or

  14. Endovascular Treatment of a Ruptured Profunda Femoral Artery Branch After Fogarty Thrombectomy of a Femoro-Femoral Crossover Arterial Graft: A Case Report and Review of the Literature

    SciTech Connect

    Manousaki, Eirini; Tsetis, Dimitrios; Kostas, Theodoros; Katsamouris, Asterios

    2010-02-15

    We present a very rare case of a life-threatening rupture of a profunda femoral artery distal branch after a Fogarty thrombectomy of a thrombosed crossover synthetic graft between the ipsilateral common femoral artery and a contralateral iliac-popliteal graft; the bleeding profunda femoral artery branch was successfully embolized with metallic coils through the axillary artery approach.

  15. Mechanism-based mathematical modeling of combined gemcitabine and birinapant in pancreatic cancer cells

    PubMed Central

    Zhu, Xu; Straubinger, Robert M.; Jusko, William J.

    2015-01-01

    Combination chemotherapy is standard treatment for pancreatic cancer. However, current drugs lack efficacy for most patients and selection and evaluation of new combination regimens is empirical and time-consuming. The efficacy of gemcitabine, a standard-of-care agent, combined with birinapant, a pro-apoptotic antagonist of Inhibitor of Apoptosis Proteins (IAPs), was investigated in pancreatic cancer cells. PANC-1 cells were treated with vehicle, gemcitabine (6, 10, 20 nM), birinapant (50, 200, 500 nM), and combinations of the two drugs. Temporal changes in cell numbers, cell cycle distribution, and apoptosis were measured. A basic pharmacodynamic (PD) model based on cell numbers, and a mechanism-based PD model integrating all measurements, were developed. The basic PD model indicated that synergistic effects occurred in both cell proliferation and death processes. The mechanism-based model captured key features of drug action: temporary cell cycle arrest in S phase induced by gemcitabine alone, apoptosis induced by birinapant alone, and prolonged cell cycle arrest and enhanced apoptosis induced by the combination. A drug interaction term ψ was employed in the models to signify interactions of the combination when data were limited. When more experimental information was utilized, ψ values approaching 1 indicated that specific mechanisms of interactions were captured better. PD modeling identified the potential benefit of combining gemcitabine and birinapant, and characterized the key interaction pathways. An optimal treatment schedule of pretreatment with gemcitabine for 24-48 h was suggested based on model prediction and was verified experimentally. This approach provides a generalizable modeling platform for exploring combinations of cytostatic and cytotoxic agents in cancer cell cultures. PMID:26252969

  16. Effects of combined mechanical stimulation on the proliferation and differentiation of pre-osteoblasts

    PubMed Central

    Kang, Kyung Shin; Lee, Seung-Jae; Lee, Haksue; Moon, Wonkyu

    2011-01-01

    We observed how combined mechanical stimuli affect the proliferation and differentiation of pre-osteoblasts. For this research, a bioreactor system was developed that can simultaneously stimulate cells with cyclic strain and ultrasound, each of which is known to effectively stimulate bone tissue regeneration. MC3T3-E1 pre-osteoblasts were chosen for bone tissue engineering due to their osteoblast-like characteristics. 3-D scaffolds were fabricated with polycaprolactone and poly-L-lactic acid using the salt leaching method. The cells were stimulated by the bioreactor with cyclic strain and ultrasound. The bioreactor was set at a frequency of 1.0 Hz and 10% strain for cyclic strain and 1.0 MHz and 30 mW/cm2 for ultrasound. Three experimental groups (ultrasound, cyclic strain, and combined stimulation) and a control group were examined. Each group was stimulated for 20 min/day. Mechanical stimuli did not affect MC3T3-E1 cell proliferation significantly up to 10 days when measured with the cell counting kit-8. However, gene expression analysis of collagen type-I, osteocalcin, RUNX2, and osterix revealed that the combined mechanical stimulation accelerated the matrix maturation of MC3T3-E1 cells. These results indicate that the combined mechanical stimulation can enhance the differentiation of pre-osteoblasts more efficiently than simple stimuli, in spite of no effect on cell proliferation. PMID:21532314

  17. [Combined hopping-superexchange mechanism of charge transfer in DNA; a model with nearest interactions].

    PubMed

    Lakhno, V D; Sultanov, V B

    2007-01-01

    In the framework of the earlier developed combined hopping-superexchange mechanism of charge transfer in DNA, a model with all nearest interactions between nucleobases is proposed. It is shown that the transfer rates for various types of nucleotide sequences calculated within this model are in a good agreement with experimental data.

  18. Robust mechanisms of ventral furrow invagination require the combination of cellular shape changes

    NASA Astrophysics Data System (ADS)

    Conte, Vito; Muñoz, José J.; Baum, Buzz; Miodownik, Mark

    2009-03-01

    Ventral furrow formation in Drosophila is the first large-scale morphogenetic movement during the life of the embryo, and is driven by co-ordinated changes in the shape of individual epithelial cells within the cellular blastoderm. Although many of the genes involved have been identified, the details of the mechanical processes that convert local changes in gene expression into whole-scale changes in embryonic form remain to be fully understood. Biologists have identified two main cell deformation modes responsible for ventral furrow invagination: constriction of the apical ends of the cells (apical wedging) and deformation along their apical-basal axes (radial lengthening/shortening). In this work, we used a computer 2D finite element model of ventral furrow formation to investigate the ability of different combinations of three plausible elementary active cell shape changes to bring about epithelial invagination: ectodermal apical-basal shortening, mesodermal apical-basal lengthening/shortening and mesodermal apical constriction. We undertook a systems analysis of the biomechanical system, which revealed many different combinations of active forces (invagination mechanisms) were able to generate a ventral furrow. Two important general features were revealed. First that combinations of shape changes are the most robust to environmental and mutational perturbation, in particular those combining ectodermal pushing and mesodermal wedging. Second, that ectodermal pushing plays a big part in all of the robust mechanisms (mesodermal forces alone do not close the furrow), and this provides evidence that it may be an important element in the mechanics of invagination in Drosophila.

  19. Clinical study on VATS combined mechanical ventilation treatment of ARDS secondary to severe chest trauma

    PubMed Central

    Qi, Yongjun

    2016-01-01

    The aim of the study was to investigate the clinical effects of microinvasive video-assisted thoracoscopic surgery (VATS) combined with mechanical ventilation in the treatment of acute respiratory distress syndrome (ARDS) secondary to severe chest trauma. A total of 62 patients with ARDS secondary to severe chest trauma were divided into the observation and control groups. The patients in the observation groups were treated with VATS combined with early mechanical ventilation while patients in the control group were treated using routine open thoracotomy combined with early mechanical ventilation. Compared to the controls, the survival rate of the observation group was significantly higher. The average operation time of the observation group was significantly shorter than that of the control group, and the incidence of complications in the perioperative period of the observation group was significantly lower than that of the control group (p<0.05). The average application time of the observation group was significantly shorter than that of the control group, and the incidence of ventilator-associated complications was significantly lower than that of the control group (p<0.05). In conclusion, a reasonable understanding of the indications and contraindications of VATS, combined with early mechanical treatment significantly improved the success rate of the treatment of ARDS patients secondary to severe chest trauma and reduced the complications. PMID:27446317

  20. Effects and Mechanism of Combination of Rhein and Danshensu in the Treatment of Chronic Kidney Disease.

    PubMed

    Guan, Yue; Wu, Xiao-Xiao; Duan, Jia-Lin; Yin, Ying; Guo, Chao; Wei, Guo; Wang, Yan-Hua; Zhu, Yan-Rong; Weng, Yan; Xi, Miao-Miao; Wen, Ai-Dong

    2015-01-01

    Traditional Chinese medicine (TCM) plays a systemic role in disease treatment, targeting multiple etiological factors simultaneously. Based on clinical experience, rhubarb and Salvia miltiorrhiza are commonly prescribed together for the treatment of chronic kidney disease (CKD) and have been proven to be very effective. However, the rationale of the combination remains unclear. The major active ingredients of these two herbs are rhein (RH) and danshensu (DSS), respectively. The aim of this paper is to investigate the renoprotective effects of RH and DSS in vitro and in vivo, and the underlying mechanism. A total of 5/6 nephrectomy rats and HK-2 cells were subjected to chronic renal injury. The combination of RH and DSS conferred a protective effect, as shown by a significant improvement in the renal function, blood supply, and fibrotic degree. Proinflammatory cytokines and adhesion molecules were suppressed by RH and DSS through NK-κB signaling. The combination also inhibited apoptosis by up-regulating Bcl-2 and down-regulating Bax. Inhibiting the TGF-β/Smad3 pathway was at least in part involved in the antifibrotic mechanism of the combination treatment of RH and DSS. This study demonstrates for the first time the renoprotective effect and the mechanism of RH and DSS combination on chronic renal injury. It could provide experimental evidence to support the rationality of the combinatorial use of TCM in clinical practices. PMID:26503560

  1. Playing Dr Jekyll and Mr Hyde: combined mechanisms of phase variation in bacteria.

    PubMed

    Hallet, B

    2001-10-01

    Phase variation is the adaptive process by which bacteria undergo frequent and reversible phenotypic changes resulting from genetic alterations in specific loci of their genomes. This process is crucial for the survival of pathogens and commensals in hostile and ever-changing host environments. Despite important differences in the molecular mechanisms that mediate and regulate phase variation, related strategies have evolved to generate high levels of genetic diversity through complex and combinatorial reshuffling of genetic information. Recent studies, supported by the emergence of global genomic approaches, have revealed that bacterial pathogens often use a combination of different mechanisms to vary the expression of a variety of biological functions, providing new insights into bacterial adaptation and virulence mechanisms. Recent advances in the understanding of the molecular mechanisms of phase variation are reviewed, and differences in these mechanisms outlined. PMID:11587935

  2. Endovascular Treatment of Phlegmasia Cerulea Dolens with Impending Venous Gangrene: Manual Aspiration Thrombectomy as the First-Line Thrombus Removal Method

    SciTech Connect

    Oguzkurt, Levent Ozkan, Ugur; Demirturk, Orhan S.; Gur, Serkan

    2011-12-15

    Purpose: Our purpose was to report the outcome of endovascular treatment with manual aspiration thrombectomy as the first-line thromboablative method for phlegmasia cerulea dolens. Methods: Between October 2006 and May 2010, seven consecutive patients (5 women, 2 men; age range, 31-80 years) with the diagnosis of phlegmasia cerulea dolens secondary to acute iliofemoral deep venous thrombosis had endovascular treatment with manual aspiration thrombectomy. Catheter-directed thrombolysis and stent placement were used as adjunctive procedures. Phlegmasia was left-sided in five and right-sided in two patients. Results: All patients had associated great saphenous vein thrombosis in addition to iliofemoral deep vein thrombosis (DVT). Aspiration thrombectomy completely removed the thrombus from the popliteal vein to the inferior vena cava (IVC) in all cases. Three patients with May-Thurner syndrome had stent placement in the left common iliac vein. Two patients had early recurrences. Repeated aspiration thrombectomy was unsuccessful in one patient. There were no complications related to the procedure. One patient who had been successfully treated died of sepsis and another patient who had unsuccessful repeated interventions had below-the-knee amputation. Overall, the clinical success and survival rates of patients in this study were 86%. On follow-up, three patients with successful treatment were asymptomatic with no deep venous insufficiency. One of these patients died during the 4-month follow-up period. Two patients had mild ankle swelling with deep venous insufficiency. Conclusions: Manual aspiration thrombectomy with adjunctive use of catheter-directed thrombolysis and stent placement is an effective endovascular treatment method with high clinical success and survival rates for phlegmasia cerulean dolens.

  3. Mechanical versus clinical data combination in selection and admissions decisions: a meta-analysis.

    PubMed

    Kuncel, Nathan R; Klieger, David M; Connelly, Brian S; Ones, Deniz S

    2013-11-01

    In employee selection and academic admission decisions, holistic (clinical) data combination methods continue to be relied upon and preferred by practitioners in our field. This meta-analysis examined and compared the relative predictive power of mechanical methods versus holistic methods in predicting multiple work (advancement, supervisory ratings of performance, and training performance) and academic (grade point average) criteria. There was consistent and substantial loss of validity when data were combined holistically-even by experts who are knowledgeable about the jobs and organizations in question-across multiple criteria in work and academic settings. In predicting job performance, the difference between the validity of mechanical and holistic data combination methods translated into an improvement in prediction of more than 50%. Implications for evidence-based practice are discussed. PMID:24041118

  4. Combination of Universal Mechanical Testing Machine with Atomic Force Microscope for Materials Research

    PubMed Central

    Zhong, Jian; He, Dannong

    2015-01-01

    Surface deformation and fracture processes of materials under external force are important for understanding and developing materials. Here, a combined horizontal universal mechanical testing machine (HUMTM)-atomic force microscope (AFM) system is developed by modifying UMTM to combine with AFM and designing a height-adjustable stabilizing apparatus. Then the combined HUMTM-AFM system is evaluated. Finally, as initial demonstrations, it is applied to analyze the relationship among macroscopic mechanical properties, surface nanomorphological changes under external force, and fracture processes of two kinds of representative large scale thin film materials: polymer material with high strain rate (Parafilm) and metal material with low strain rate (aluminum foil). All the results demonstrate the combined HUMTM-AFM system overcomes several disadvantages of current AFM-combined tensile/compression devices including small load force, incapability for large scale specimens, disability for materials with high strain rate, and etc. Therefore, the combined HUMTM-AFM system is a promising tool for materials research in the future. PMID:26265357

  5. Combined optical and mechanical scanning in optical-resolution photoacoustic microscopy

    NASA Astrophysics Data System (ADS)

    Li, Lei; Yeh, Chenghung; Hu, Song; Wang, Lidai; Soetikno, Brian T.; Chen, Ruimin; Zhou, Qifa; Shung, K. Kirk; Maslov, Konstantin I.; Wang, Lihong V.

    2014-03-01

    Combined optical and mechanical scanning (COMS) in optical-resolution photoacoustic microscopy (OR-PAM) has provided five scanning modes with fast imaging speed and wide field of view (FOV). With two-dimensional (2D) galvanometer-based optical scanning, we have achieved a 2 KHz B-scan rate and 50 Hz volumetric-scan rate, which enables real-time tracking of cell activities in vivo. With optical-mechanical hybrid 2D scanning, we are able to image a wide FOV (10×8 mm2) within 150 seconds, which is 20 times faster than the conventional mechanical scan in our second-generation OR-PAM. With three-dimensional mechanical-based contour scanning, we can maintain the optimal signal-to-noise ratio and spatial resolution of OR-PAM while imaging objects with uneven surfaces, which is ideal for fast and quantitative studies of tumors and the brain.

  6. An Opportunistic Routing Mechanism Combined with Long-Term and Short-Term Metrics for WMN

    PubMed Central

    Piao, Xianglan; Qiu, Tie

    2014-01-01

    WMN (wireless mesh network) is a useful wireless multihop network with tremendous research value. The routing strategy decides the performance of network and the quality of transmission. A good routing algorithm will use the whole bandwidth of network and assure the quality of service of traffic. Since the routing metric ETX (expected transmission count) does not assure good quality of wireless links, to improve the routing performance, an opportunistic routing mechanism combined with long-term and short-term metrics for WMN based on OLSR (optimized link state routing) and ETX is proposed in this paper. This mechanism always chooses the highest throughput links to improve the performance of routing over WMN and then reduces the energy consumption of mesh routers. The simulations and analyses show that the opportunistic routing mechanism is better than the mechanism with the metric of ETX. PMID:25250379

  7. Aspiration Thrombectomy and Drug-Eluting Stent Implantation Decrease the Occurrence of Angina Pectoris One Year After Acute Myocardial Infarction

    PubMed Central

    Lee, Wei-Chieh; Fang, Chih-Yuan; Chen, Huang-Chung; Hsueh, Shu-Kai; Chen, Chien-Jen; Yang, Cheng-Hsu; Yip, Hon-Kan; Hang, Chi-Ling; Wu, Chiung-Jen; Fang, Hsiu-Yu

    2016-01-01

    Abstract Angina pectoris is a treatable symptom that is associated with mortality and decreased quality of life. Angina eradication is a primary care goal of care after an acute myocardial infarction (AMI). Our aim was to evaluate factors influencing angina pectoris 1 year after an AMI. From January 2005 to December 2013, 1547 patient received primary percutaneous intervention in our hospital for an acute ST-segment elevation myocardial infarction (MI). Of these patients, 1336 patients did not experience post-MI angina during a 1-year follow-up, and 211 patients did. Univariate and multivariate logistic regression analyses were performed to identify the factors influencing angina pectoris 1 year after an AMI. Propensity score matched analyses were performed for subgroups analyses. The average age of the patients was 61.08 ± 12.77 years, with a range of 25 to 97 years, and 82.9% of the patients were male. During 1-year follow-up, 13.6% of the patients experienced post-MI angina. There was a longer chest pain-to-reperfusion time in the post-MI angina group (P = 0.01), as well as a higher fasting sugar level, glycohemoglobin (HbA1C), serum creatinine, troponin-I and creatine kinase MB (CK-MB). The post-MI angina group also had a higher prevalence of multiple-vessel disease. Manual thrombectomy, and distal protective device and intracoronary glycoprotein IIb/IIIa inhibitor injection were used frequently in the no post-MI angina group. Antiplatelet agents and post-MI medication usage were similar between the 2 groups. Multivariate logistic regression analyses demonstrated that prior MI was a positive independent predictor of occurrence of post-MI angina. Manual thrombectomy use and drug-eluting stent implantation were negative independent predictors of post-MI angina. Higher troponin-I and longer chest pain-to-reperfusion time exhibited a trend toward predicting post-MI angina. Prior MIs were strong, independent predictors of post-MI angina. Manual thrombectomy

  8. Aspiration Thrombectomy and Drug-Eluting Stent Implantation Decrease the Occurrence of Angina Pectoris One Year After Acute Myocardial Infarction.

    PubMed

    Lee, Wei-Chieh; Fang, Chih-Yuan; Chen, Huang-Chung; Hsueh, Shu-Kai; Chen, Chien-Jen; Yang, Cheng-Hsu; Yip, Hon-Kan; Hang, Chi-Ling; Wu, Chiung-Jen; Fang, Hsiu-Yu

    2016-04-01

    Angina pectoris is a treatable symptom that is associated with mortality and decreased quality of life. Angina eradication is a primary care goal of care after an acute myocardial infarction (AMI). Our aim was to evaluate factors influencing angina pectoris 1 year after an AMI.From January 2005 to December 2013, 1547 patient received primary percutaneous intervention in our hospital for an acute ST-segment elevation myocardial infarction (MI). Of these patients, 1336 patients did not experience post-MI angina during a 1-year follow-up, and 211 patients did. Univariate and multivariate logistic regression analyses were performed to identify the factors influencing angina pectoris 1 year after an AMI. Propensity score matched analyses were performed for subgroups analyses.The average age of the patients was 61.08 ± 12.77 years, with a range of 25 to 97 years, and 82.9% of the patients were male. During 1-year follow-up, 13.6% of the patients experienced post-MI angina. There was a longer chest pain-to-reperfusion time in the post-MI angina group (P = 0.01), as well as a higher fasting sugar level, glycohemoglobin (HbA1C), serum creatinine, troponin-I and creatine kinase MB (CK-MB). The post-MI angina group also had a higher prevalence of multiple-vessel disease. Manual thrombectomy, and distal protective device and intracoronary glycoprotein IIb/IIIa inhibitor injection were used frequently in the no post-MI angina group. Antiplatelet agents and post-MI medication usage were similar between the 2 groups. Multivariate logistic regression analyses demonstrated that prior MI was a positive independent predictor of occurrence of post-MI angina. Manual thrombectomy use and drug-eluting stent implantation were negative independent predictors of post-MI angina. Higher troponin-I and longer chest pain-to-reperfusion time exhibited a trend toward predicting post-MI angina.Prior MIs were strong, independent predictors of post-MI angina. Manual thrombectomy and drug

  9. The analgesic effect and mechanism of the combination of sodium ferulate and oxymatrine.

    PubMed

    Liu, Hanqing; Sun, Yan; Gao, Yan; Chen, Fangfang; Xu, MingBo; Liu, Zhifeng

    2010-09-01

    Sodium ferulate (SF) and Oxymatrine (OMT) were compounds extracted from Chinese herbs, and have been used in clinical treatment of heart and hepatic diseases, respectively, in China for many years. The objective of this study was to examine the analgesic effect and the mechanism of the combined treatment of SF and OMT. Using the animal pain models by applying Acetic Acid Writhing Test and Formalin Test, the combination of SF and OMT showed significant analgesic effect in dose-dependent manner. In vitro, the combined treatment inhibited the increase in intracellular calcium concentration evoked by capsaicin in the dorsal root ganglion neurons. Importantly, a synergistic inhibitory effect of SF and OMT on the capsaicin-induced currents was demonstrated by whole-cell patch-clamp. Our results suggest that SF and OMT cause significant analgesic effect which maybe related to the synergistic inhibition of transient receptor potential vanilloid-1.

  10. Combination therapy including serratiopeptidase improves outcomes of mechanical-antibiotic treatment of periimplantitis.

    PubMed

    Sannino, G; Gigola, P; Puttini, M; Pera, F; Passariello, C

    2013-01-01

    This study was designed as a retrospective analysis of clinical outcomes of cases of periimplantitis treated by mechanical debridement and the administration of antibiotics combined or not with the administration of either the proteolytic enzyme serratiopeptidase (SPEP) or non-steroidal anti-inflammatory drugs (NSAIDs). Clinical charts of 544 partially edentulous patients treated for periimplantitis between June 1996 and December 2010 were analyzed to obtain clinical data of the affected implants just before the beginning of treatment and 12 months later to evaluate the outcomes of combined mechanical antibiotic treatment alone or in combination with the co-administration of the anti-inflammatory SPEP or NSAIDs. The comparative analysis revealed that therapeutic outcomes were significantly different in the three groups. Failure rate in the group that received SPEP (6 percent) was significantly lower compared to the group that received NSAIDS (16.9 percent; P less than 0.01) and to the group that received no anti-inflammatory therapy (18.9 percent; P less than 0.01). Treatment including SPEP was associated with significantly better healing also when successful treatments alone were considered. The data reported in this paper strongly support the hypothesis that SPEP is a valid addition to protocols for the combined therapy of peri-implantitis. In fact, it allows to enhance success rates significantly and also favors better tissue repair around successfully treated implants as compared to other regimens.

  11. Synergistic intracellular iron chelation combinations: mechanisms and conditions for optimizing iron mobilization.

    PubMed

    Vlachodimitropoulou Koumoutsea, Evangelia; Garbowski, Maciej; Porter, John

    2015-09-01

    Iron chelators are increasingly combined clinically but the optimal conditions for cellular iron mobilization and mechanisms of interaction are unclear. Speciation plots for iron(III) binding of paired combinations of the licensed iron chelators desferrioxamine (DFO), deferiprone (DFP) and deferasirox (DFX) suggest conditions under which chelators can combine as 'shuttle' and 'sink' molecules but this approach does not consider their relative access and interaction with cellular iron pools. To address this issue, a sensitive ferrozine-based detection system for intracellular iron removal from the human hepatocyte cell line (HuH-7) was developed. Antagonism, synergism or additivity with paired chelator combinations was distinguished using mathematical isobologram analysis over clinically relevant chelator concentrations. All combinations showed synergistic iron mobilization at 8 h with clinically achievable concentrations of sink and shuttle chelators. Greatest synergism was achieved by combining DFP with DFX, where about 60% of mobilized iron was attributable to synergistic interaction. These findings predict that the DFX dose required for a half-maximum effect can be reduced by 3·8-fold when only 1 μmol/l DFP is added. Mechanisms for the synergy are suggested by consideration of the iron-chelate speciation plots together with the size, charge and lipid solubilities for each chelator. Hydroxypyridinones with low lipid solubilities but otherwise similar properties to DFP were used to interrogate the mechanistic interactions of chelator pairs. These studies confirm that synergistic cellular iron mobilization requires one chelator to have the physicochemical properties to enter cells, chelate intracellular iron and subsequently donate iron to a second 'sink' chelator.

  12. Synergistic intracellular iron chelation combinations: mechanisms and conditions for optimizing iron mobilization.

    PubMed

    Vlachodimitropoulou Koumoutsea, Evangelia; Garbowski, Maciej; Porter, John

    2015-09-01

    Iron chelators are increasingly combined clinically but the optimal conditions for cellular iron mobilization and mechanisms of interaction are unclear. Speciation plots for iron(III) binding of paired combinations of the licensed iron chelators desferrioxamine (DFO), deferiprone (DFP) and deferasirox (DFX) suggest conditions under which chelators can combine as 'shuttle' and 'sink' molecules but this approach does not consider their relative access and interaction with cellular iron pools. To address this issue, a sensitive ferrozine-based detection system for intracellular iron removal from the human hepatocyte cell line (HuH-7) was developed. Antagonism, synergism or additivity with paired chelator combinations was distinguished using mathematical isobologram analysis over clinically relevant chelator concentrations. All combinations showed synergistic iron mobilization at 8 h with clinically achievable concentrations of sink and shuttle chelators. Greatest synergism was achieved by combining DFP with DFX, where about 60% of mobilized iron was attributable to synergistic interaction. These findings predict that the DFX dose required for a half-maximum effect can be reduced by 3·8-fold when only 1 μmol/l DFP is added. Mechanisms for the synergy are suggested by consideration of the iron-chelate speciation plots together with the size, charge and lipid solubilities for each chelator. Hydroxypyridinones with low lipid solubilities but otherwise similar properties to DFP were used to interrogate the mechanistic interactions of chelator pairs. These studies confirm that synergistic cellular iron mobilization requires one chelator to have the physicochemical properties to enter cells, chelate intracellular iron and subsequently donate iron to a second 'sink' chelator. PMID:26033030

  13. Synergistic chemoprotective mechanisms of dietary phytoestrogens in a select combination against prostate cancer.

    PubMed

    Kumar, Rajeev; Verma, Vikas; Jain, Ashish; Jain, Rajeev K; Maikhuri, Jagdamba P; Gupta, Gopal

    2011-08-01

    Combination of dietary phytoestrogens with diverse molecular mechanisms may enhance their anticancer efficacy at physiological concentrations, as evidenced in epidemiological studies. A select combination of three dietary phytoestrogens containing 8.33 μM each of genistein (G), quercetin (Q) and biochanin A (B) was found to be more potent in inhibiting the growth of androgen-responsive prostate cancer cells (LNCaP) as well as DU-145 and PC-3 prostate cancer cells in vitro than either 25 μM of G, B or Q or 12.5+12.5 μM of G+Q, Q+B or G+B. Subsequent mechanistic studies in PC-3 cells indicated that the action of phytoestrogens was mediated both through estrogen receptor (ER)-dependent and ER-independent pathways as potent estrogen antagonist ICI-182780 (ICI, 5 μM) could not completely mask the synergistic anticancer effects, which were sustained appreciably in presence of ICI. G+Q+B combination was significantly more effective than individual compounds or their double combinations in increasing ER-β, bax (mRNA expression); phospho-JNK, bax (protein levels); and in decreasing bcl-2, cyclin E, c-myc (mRNA expression); phospho-AKT, phospho-ERK, bcl-2, proliferating cell nuclear antigen (protein levels) in PC-3 cells. Phytoestrogens also synergistically stimulated caspase-3 activity. Our findings suggest that selectively combining anticancer phytoestrogens could significantly increase the efficacy of individual components resulting in improved efficacy at physiologically achievable concentrations. The combination mechanism of multiple anticancer phytochemicals may be indicative of the potential of some vegetarian diet components to elicit chemopreventive effects against prostate cancer at their physiologically achievable concentrations, in vivo.

  14. The Use of the 'Preclosure' Technique for Antegrade Aspiration Thrombectomy with Large Catheters in Acute Limb Ischemia

    SciTech Connect

    Funke, C. Pfiffner, R.; Husmann, M.; Pfammatter, T.

    2013-04-15

    This study was designed to assess retrospectively short- and mid-term outcomes of the use of a suture-mediated closure device to close the antegrade access in patients undergoing percutaneous aspiration thrombectomy with large catheters for acute leg ischemia. Between November 2005 and February 2010, a suture-mediated active closure system (ProGlide{sup Registered-Sign} 6F, Abbott) was placed before arterial sheath (mean 9 F, range 6-12 F) introduction in 101 patients (74 men, 73 %, mean age 70.1 {+-} 12.6 years standard deviation). Data regarding mortality, complications, and factors contributing to vascular complications at the access site was collected for 6 month after the intervention to detect device-related problems. As a coincidence, 77 patients had follow-up visits for a duplex ultrasound. There were a total of 19 vascular complications (19 %) at the puncture site, all of which were of hemorrhagic nature and none of which consisted of vessel occlusion. Two major outcome complications (2 %) occurred. A retroperitoneal hematoma and a serious inguinal bleeding required additive treatment and did not result in permanent sequelae. Nine cases involved death of which eight were not attributable to the closure and one remained unclear. Successful closure was achieved in 95 patients (94 %); additional manual compression was sufficient in the majority of the remaining patients. Numerous factors contributing to vascular complications were encountered. With acceptable short- and mid-term outcomes, the 'preclose' technique can be a reliable option for the closure of a large antegrade femoral access even for patients at a high risk of vascular complications, such as those undergoing aspiration thrombectomy.

  15. Modified technique of cavoatrial tumor thrombectomy without cardiopulmonary by-pass and hypothermic circulatory arrest: a preliminary report

    PubMed Central

    Sobczyński, Robert; Przydacz, Mikolaj; Wiatr, Tomasz; Bukowczan, Jakub; Sadowski, Jerzy; Chłosta, Piotr

    2015-01-01

    Introduction Traditionally, tumor thrombi extending into the right atrium have been managed by open surgery with sternotomy, cardiopulmonary bypass circulation and hypothermic circulatory arrest, and are associated with significant morbidity and mortality rates. Here, we evaluate the results of cavoatrial thrombectomy using our own, Foley catheter assisted-technique, obviating the need for thoracotomy, extracorporeal circulation, and/or hypothermic circulatory arrest. Material and methods Between June 2013 and January 2015, 4 consecutive patients underwent cavoatrial thrombectomy performed with our own, Foley catheter assisted technique, via Chevron incision, with no need for extracorporeal circulation or hypothermy for renal cell carcinoma with tumor thrombus extending into the right atrium. Analyses of patients’ data from a prospectively maintained database with respect to perioperative characteristics, morbidity and mortality were performed. Results The total mean duration of surgery was 255 minutes. The mean time of total IVC (inferior vena cava) occlusion was 90 seconds. The average blood loss volume, timed from the beginning of cavotomy incision until its closure, was 1200 ml. The total mean intraoperative blood loss was 3,150 ml. There was no perioperative death. Postoperative complications included one transient acute kidney injury requiring one-off hemodialysis and one re-operation due to bleeding. The follow-up time ranged between 12 to 17 months. None of the patients developed disease recurrence. All patients were still alive at the time of study completion. Conclusions Obtained results support the validity of our own, Foley catheter assisted technique, without cardiopulmonary bypass and hypothermic circulatory arrest for the treatment of renal cell carcinoma with tumor thrombus extending into the right atrium. PMID:26568872

  16. Measuring the mechanical properties of plant cells by combining micro-indentation with osmotic treatments

    PubMed Central

    Weber, Alain; Braybrook, Siobhan; Huflejt, Michal; Mosca, Gabriella; Routier-Kierzkowska, Anne-Lise; Smith, Richard S.

    2015-01-01

    Growth in plants results from the interaction between genetic and signalling networks and the mechanical properties of cells and tissues. There has been a recent resurgence in research directed at understanding the mechanical aspects of growth, and their feedback on genetic regulation. This has been driven in part by the development of new micro-indentation techniques to measure the mechanical properties of plant cells in vivo. However, the interpretation of indentation experiments remains a challenge, since the force measures results from a combination of turgor pressure, cell wall stiffness, and cell and indenter geometry. In order to interpret the measurements, an accurate mechanical model of the experiment is required. Here, we used a plant cell system with a simple geometry, Nicotiana tabacum Bright Yellow-2 (BY-2) cells, to examine the sensitivity of micro-indentation to a variety of mechanical and experimental parameters. Using a finite-element mechanical model, we found that, for indentations of a few microns on turgid cells, the measurements were mostly sensitive to turgor pressure and the radius of the cell, and not to the exact indenter shape or elastic properties of the cell wall. By complementing indentation experiments with osmotic experiments to measure the elastic strain in turgid cells, we could fit the model to both turgor pressure and cell wall elasticity. This allowed us to interpret apparent stiffness values in terms of meaningful physical parameters that are relevant for morphogenesis. PMID:25873663

  17. Measuring the mechanical properties of plant cells by combining micro-indentation with osmotic treatments.

    PubMed

    Weber, Alain; Braybrook, Siobhan; Huflejt, Michal; Mosca, Gabriella; Routier-Kierzkowska, Anne-Lise; Smith, Richard S

    2015-06-01

    Growth in plants results from the interaction between genetic and signalling networks and the mechanical properties of cells and tissues. There has been a recent resurgence in research directed at understanding the mechanical aspects of growth, and their feedback on genetic regulation. This has been driven in part by the development of new micro-indentation techniques to measure the mechanical properties of plant cells in vivo. However, the interpretation of indentation experiments remains a challenge, since the force measures results from a combination of turgor pressure, cell wall stiffness, and cell and indenter geometry. In order to interpret the measurements, an accurate mechanical model of the experiment is required. Here, we used a plant cell system with a simple geometry, Nicotiana tabacum Bright Yellow-2 (BY-2) cells, to examine the sensitivity of micro-indentation to a variety of mechanical and experimental parameters. Using a finite-element mechanical model, we found that, for indentations of a few microns on turgid cells, the measurements were mostly sensitive to turgor pressure and the radius of the cell, and not to the exact indenter shape or elastic properties of the cell wall. By complementing indentation experiments with osmotic experiments to measure the elastic strain in turgid cells, we could fit the model to both turgor pressure and cell wall elasticity. This allowed us to interpret apparent stiffness values in terms of meaningful physical parameters that are relevant for morphogenesis.

  18. Mechanism of Sporicidal Activity for the Synergistic Combination of Peracetic Acid and Hydrogen Peroxide

    PubMed Central

    Leggett, Mark J.; Schwarz, J. Spencer; Burke, Peter A.; McDonnell, Gerald; Denyer, Stephen P.

    2015-01-01

    There is still great interest in controlling bacterial endospores. The use of chemical disinfectants and, notably, oxidizing agents to sterilize medical devices is increasing. With this in mind, hydrogen peroxide (H2O2) and peracetic acid (PAA) have been used in combination, but until now there has been no explanation for the observed increase in sporicidal activity. This study provides information on the mechanism of synergistic interaction of PAA and H2O2 against bacterial spores. We performed investigations of the efficacies of different combinations, including pretreatments with the two oxidizers, against wild-type spores and a range of spore mutants deficient in the spore coat or small acid-soluble spore proteins. The concentrations of the two biocides were also measured in the reaction vessels, enabling the assessment of any shift from H2O2 to PAA formation. This study confirmed the synergistic activity of the combination of H2O2 and PAA. However, we observed that the sporicidal activity of the combination is largely due to PAA and not H2O2. Furthermore, we observed that the synergistic combination was based on H2O2 compromising the spore coat, which was the main spore resistance factor, likely allowing better penetration of PAA and resulting in the increased sporicidal activity. PMID:26637595

  19. Mechanism of Sporicidal Activity for the Synergistic Combination of Peracetic Acid and Hydrogen Peroxide.

    PubMed

    Leggett, Mark J; Schwarz, J Spencer; Burke, Peter A; McDonnell, Gerald; Denyer, Stephen P; Maillard, Jean-Yves

    2016-02-01

    There is still great interest in controlling bacterial endospores. The use of chemical disinfectants and, notably, oxidizing agents to sterilize medical devices is increasing. With this in mind, hydrogen peroxide (H2O2) and peracetic acid (PAA) have been used in combination, but until now there has been no explanation for the observed increase in sporicidal activity. This study provides information on the mechanism of synergistic interaction of PAA and H2O2 against bacterial spores. We performed investigations of the efficacies of different combinations, including pretreatments with the two oxidizers, against wild-type spores and a range of spore mutants deficient in the spore coat or small acid-soluble spore proteins. The concentrations of the two biocides were also measured in the reaction vessels, enabling the assessment of any shift from H2O2 to PAA formation. This study confirmed the synergistic activity of the combination of H2O2 and PAA. However, we observed that the sporicidal activity of the combination is largely due to PAA and not H2O2. Furthermore, we observed that the synergistic combination was based on H2O2 compromising the spore coat, which was the main spore resistance factor, likely allowing better penetration of PAA and resulting in the increased sporicidal activity. PMID:26637595

  20. Liraglutide, leptin, and their combined effects on feeding: additive intake reduction through common intracellular signaling mechanisms

    PubMed Central

    Kanoski, Scott E.; Ong, Zhi Yi; Fortin, Samantha M.; Schlessinger, Elizabeth S.; Grill, Harvey J.

    2014-01-01

    Aims Glucagon like peptide-1 receptor (GLP-1R) agonists and leptin each exert anorexigenic effects. In combination, the intake inhibitory and weight loss effects are greater than either treatment alone, however the mechanisms unclear. Materials and methods Effects of liraglutide (a long-acting GLP-1 analogue) and leptin co-treatment, delivered in low or moderate doses subcutaneously (SC) or to the 3rd ventricle respectively, on cumulative intake, meal patterns, and hypothalamic expression of intracellular signaling proteins [phosphorylated signal transducer and activator of transcription-3 (pSTAT3) and protein tyrosine phosphatase-1B (PTP1B)] were examined in lean rats. Results A low-dose combination of liraglutide (25μg/kg) and leptin (0.75μg) additively reduced cumulative food intake and body weight, a result mediated predominantly through a significant reduction in meal frequency that was not present with either drug alone. Liraglutide treatment alone also reduced meal size; an effect not enhanced with leptin co-administration. Moderate doses of liraglutide (75μg/kg) and leptin (4μg) examined separately each reduced meal frequency, cumulative food intake, and body weight; only liraglutide reduced meal size. In combination these doses did not further enhance the anorexigenic effects of either treatment alone. Ex vivo immunoblot showed elevated pSTAT3 in hypothalamic tissue following liraglutide-leptin co-treatment, an effect greater than leptin treatment alone. In addition, SC liraglutide reduced expression of PTP1B (a negative regulator of leptin receptor signaling), revealing a potential mechanism for the enhanced pSTAT3 response following liraglutide-leptin co-administration. Conclusions Collectively, these results provide novel behavioral and molecular mechanisms underlying the additive reduction in food intake and body weight following liraglutide-leptin combination treatment. PMID:25475828

  1. Reaction mechanism of manganese superoxide dismutase studied by combined quantum and molecular mechanical calculations and multiconfigurational methods.

    PubMed

    Srnec, Martin; Aquilante, Francesco; Ryde, Ulf; Rulísek, Lubomír

    2009-04-30

    Manganese superoxide dismutases (MnSODs) are enzymes that convert two molecules of the poisonous superoxide radical into molecular oxygen and hydrogen peroxide. During the reaction, the manganese ion cycles between the Mn(2+) and Mn(3+) oxidation states and accomplishes its enzymatic action in two half-cycles (corresponding to the oxidation and reduction of O(2)(-)). Despite many experimental and theoretical studies dealing with SODs, including quantum chemical active-site-model studies of numerous variants of the reaction mechanisms, several details of MnSOD enzymatic action are still unclear. In this study, we have modeled and compared four reaction pathways (one associative, one dissociative, and two second-sphere) in a protein environment using the QM/MM approach (combined quantum and molecular mechanics calculations) at the density functional theory level. The results were complemented by CASSCF/CASPT2/MM single-point energy calculations for the most plausible models to account properly for the multireference character of the various spin multiplets. The results indicate that the oxidation of O(2)(-) to O(2) most likely occurs by an associative mechanism following a two-state (quartet-octet) reaction profile. The barrier height is estimated to be less than 25 kJ.mol(-1). On the other hand, the conversion of O(2)(-) to H(2)O(2) is likely to take place by a second-sphere mechanism, that is, without direct coordination of the superoxide radical to the manganese center. The reaction pathway involves the conical intersection of two quintet states, giving rise to an activation barrier of approximately 60 kJ.mol(-1). The calculations also indicate that the associative mechanism can represent a competitive pathway in the second half-reaction with the overall activation barrier being only slightly higher than the activation barrier in the second-sphere mechanism. The activation barriers along the proposed reaction pathways are in very good agreement with the

  2. COMBINE*: An integrated opto-mechanical tool for laser performance modeling

    NASA Astrophysics Data System (ADS)

    Rehak, M.; Di Nicola, J. M.

    2015-02-01

    Accurate modeling of thermal, mechanical and optical processes is important for achieving reliable, high-performance high energy lasers such as those at the National Ignition Facility [1] (NIF). The need for this capability is even more critical for high average power, high repetition rate applications. Modeling the effects of stresses and temperature fields on optical properties allows for optimal design of optical components and more generally of the architecture of the laser system itself. Stresses change the indices of refractions and induce inhomogeneities and anisotropy. We present a modern, integrated analysis tool that efficiently produces reliable results that are used in our laser propagation tools such as VBL [5]. COMBINE is built on and supplants the existing legacy tools developed for the previous generations of lasers at LLNL but also uses commercially available mechanical finite element codes ANSYS or COMSOL (including computational fluid dynamics). The COMBINE code computes birefringence and wave front distortions due to mechanical stresses on lenses and slabs of arbitrary geometry. The stresses calculated typically originate from mounting support, vacuum load, gravity, heat absorption and/or attending cooling. Of particular importance are the depolarization and detuning effects of nonlinear crystals due to thermal loading. Results are given in the form of Jones matrices, depolarization maps and wave front distributions. An incremental evaluation of Jones matrices and ray propagation in a 3D mesh with a stress and temperature field is performed. Wavefront and depolarization maps are available at the optical aperture and at slices within the optical element. The suite is validated, user friendly, supported, documented and amenable to collaborative development. * COMBINE stands for Code for Opto-Mechanical Birefringence Integrated Numerical Evaluations.

  3. Promise of combined hydrothermal/chemical and mechanical refining for pretreatment of woody and herbaceous biomass.

    PubMed

    Kim, Sun Min; Dien, Bruce S; Singh, Vijay

    2016-01-01

    Production of advanced biofuels from woody and herbaceous feedstocks is moving into commercialization. Biomass needs to be pretreated to overcome the physicochemical properties of biomass that hinder enzyme accessibility, impeding the conversion of the plant cell walls to fermentable sugars. Pretreatment also remains one of the most costly unit operations in the process and among the most critical because it is the source of chemicals that inhibit enzymes and microorganisms and largely determines enzyme loading and sugar yields. Pretreatments are categorized into hydrothermal (aqueous)/chemical, physical, and biological pretreatments, and the mechanistic details of which are briefly outlined in this review. To leverage the synergistic effects of different pretreatment methods, conducting two or more pretreatments consecutively has gained attention. Especially, combining hydrothermal/chemical pretreatment and mechanical refining, a type of physical pretreatment, has the potential to be applied to an industrial plant. Here, the effects of the combined pretreatment (combined hydrothermal/chemical pretreatment and mechanical refining) on energy consumption, physical structure, sugar yields, and enzyme dosage are summarized. PMID:27141232

  4. Biodiesel production from palm oil using combined mechanical stirred and ultrasonic reactor.

    PubMed

    Choedkiatsakul, I; Ngaosuwan, K; Cravotto, G; Assabumrungrat, S

    2014-07-01

    This paper investigates the production of biodiesel from palm oil using a combined mechanical stirred and ultrasonic reactor (MS-US). The incorporation of mechanical stirring into the ultrasonic reactor explored the further improvement the transesterification of palm oil. Initial reaction rate values were 54.1, 142.9 and 164.2 mmol/L min for the mechanical-stirred (MS), ultrasonic (US) and MS-US reactors, respectively. Suitable methanol to oil molar ratio and the catalyst loading values were found to be 6 and 1 of oil, respectively. The effect of ultrasonic operating parameters; i.e. frequency, location, and number of transducer, has been investigated. Based on the conversion yield at the reactor outlet after 1 h, the number of transducers showed a relevant role in the reaction rate. Frequency and transducer location would appear to have no significant effect. The properties of the obtained biodiesel (density, viscosity, pour point, and flash point) satisfy the ASTM standard. The combined MS-US reactors improved the reaction rate affording the methyl esters in higher yield. PMID:24418101

  5. Effect of Combined Treatment Using Wilfortrine and Paclitaxel in Liver Cancer and Related Mechanism

    PubMed Central

    Li, Shuzhen; Zheng, Lei

    2016-01-01

    Background Liver cancer is a common malignant tumor with high mortality. Currently, effective medicines against liver cancer are still lacking. Paclitaxel is a wide-spectrum anti-tumor agent, while wilfortrine has been shown to have an inhibitory effect on the proliferation of liver cancer cells. This study thus investigated the potential effect of paclitaxel combined with wilfortrine on cultured liver cancer cells and related mechanisms, in order to provide evidence for pathogenesis and treatment of liver cancer. Material/Methods Liver cancer cell line HpeG2 was divided into control, paclitaxel, wilfortrine, and combined treatment groups. Cell proliferation was tested by MTT, while invasion was detected in Transwell chamber assay. Apoptotic protein Bcl-2 and Bax expression levels were further quantified using real-time PCR and Western blotting. Results Both of those 2 drugs can effectively inhibit cancer cell proliferation, depress invasion ability, increase Bcl-2 expression, and elevate Bax expression levels (p<0.05 in all cases). The combined therapy had better treatment efficacy compared to either of those drugs alone (p<0.05). Conclusions The combined treatment using wilfortrine and paclitaxel can inhibit proliferation and invasion of liver cancer cells via down-regulating Bcl-2 and up-regulating Bax, with better efficacy than single use of either drug. PMID:27043783

  6. Quantifying subpopulation synergy for antibiotic combinations via mechanism-based modeling and a sequential dosing design.

    PubMed

    Landersdorfer, Cornelia B; Ly, Neang S; Xu, Hongmei; Tsuji, Brian T; Bulitta, Jürgen B

    2013-05-01

    Quantitative modeling of combination therapy can describe the effects of each antibiotic against multiple bacterial populations. Our aim was to develop an efficient experimental and modeling strategy that evaluates different synergy mechanisms using a rapidly killing peptide antibiotic (nisin) combined with amikacin or linezolid as probe drugs. Serial viable counts over 48 h were obtained in time-kill experiments with all three antibiotics in monotherapy against a methicillin-resistant Staphylococcus aureus USA300 strain (inoculum, 10(8) CFU/ml). A sequential design (initial dosing of 8 or 32 mg/liter nisin, switched to amikacin or linezolid at 1.5 h) assessed the rate of killing by amikacin and linezolid against nisin-intermediate and nisin-resistant populations. Simultaneous combinations were additionally studied and all viable count profiles comodeled in S-ADAPT and NONMEM. A mechanism-based model with six populations (three for nisin times two for amikacin) yielded unbiased and precise (r = 0.99, slope = 1.00; S-ADAPT) individual fits. The second-order killing rate constants for nisin against the three populations were 5.67, 0.0664, and 0.00691 liter/(mg · h). For amikacin, the maximum killing rate constants were 10.1 h(-1) against its susceptible and 0.771 h(-1) against its less-susceptible populations, with 14.7 mg/liter amikacin causing half-maximal killing. After incorporating the effects of nisin and amikacin against each population, no additional synergy function was needed. Linezolid inhibited successful bacterial replication but did not efficiently kill populations less susceptible to nisin. Nisin plus amikacin achieved subpopulation synergy. The proposed sequential and simultaneous dosing design offers an efficient approach to quantitatively characterize antibiotic synergy over time and prospectively evaluate antibiotic combination dosing strategies. PMID:23478962

  7. Structural Stability of a Stiffened Aluminum Fuselage Panel Subjected to Combined Mechanical and Internal Pressure Loads

    NASA Technical Reports Server (NTRS)

    Rouse, Marshall; Young, Richard D.; Gehrki, Ralph R.

    2003-01-01

    Results from an experimental and analytical study of a curved stiffened aluminum panel subjected to combined mechanical and internal pressure loads are presented. The panel loading conditions were simulated using a D-box test fixture. Analytical buckling load results calculated from a finite element analysis are presented and compared to experimental results. Buckling results presented indicate that the buckling load of the fuselage panel is significantly influenced by internal pressure loading. The experimental results suggest that the stress distribution is uniform in the panel prior to buckling. Nonlinear finite element analysis results correlates well with experimental results up to buckling.

  8. Combined use of nitrogen and coatings to improve the quality of mechanically harvested Manzanilla olives.

    PubMed

    Ramírez, Eva; Sánchez, Antonio H; Romero, Concepción; Brenes, Manuel

    2015-03-15

    The combined effect of an edible coating and a nitrogen atmosphere on the quality of Manzanilla olives mechanically harvested and processed as Spanish-style green olives was assessed. The percentage of olives free of any brown spots ranged between 35-50%, 10-25% and 50-65% for fruit directly processed, storage under nitrogen and coated and storage under nitrogen respectively. Moreover, olives stored in the open air developed brown spots due to the oxidation of oleuropein. By contrast, the anoxic conditions prevented oleuropein from undergoing enzymatic oxidation but not from its enzymatic hydrolysis. Hence, the phenolic derivative HyEDA was formed in olives stored under nitrogen, and this substance was rapidly oxidized in the open air to give rise to brown spots although to a lesser extent in the coated fruit. Therefore, the postharvest storage of coated olives under nitrogen can be a good method to prevent bruise damage in mechanically harvested fruit.

  9. Modeling stresses in piezoelectric smart structures under combined thermal and mechanical excitations

    NASA Astrophysics Data System (ADS)

    Koko, Tamunoiyala S.; Smith, Malcolm J.; Orisamolu, Irewole R.

    1999-06-01

    In this paper, the integrated finite element methodology developed in our earlier work for designing active vibration control strategies in smart structures, is extended to compute the stresses and strains in the structure, due to combined thermal, mechanical and electrical excitations. A layered composite brick elements with linear strain-displacement and linear thermopiezoelectric constitutive relations is used to model the structure. The method, which has been encoded into a software called SMARTCOM provides a design and analysis capability that simultaneously accounts for the coupled thermopiezoelectric and control capabilities of the smart structural systems. Numerical examples are provided for structures with surface bonded piezoelectric sensors and actuators, under various types of mechanical, thermal and electrical load. Comparisons are made to other available solutions to verify the accuracy of the SMARTCOM simulations. The method provides accurate results and is seen as a valuable tool for the design and analysis of these smart structures.

  10. Combined use of nitrogen and coatings to improve the quality of mechanically harvested Manzanilla olives.

    PubMed

    Ramírez, Eva; Sánchez, Antonio H; Romero, Concepción; Brenes, Manuel

    2015-03-15

    The combined effect of an edible coating and a nitrogen atmosphere on the quality of Manzanilla olives mechanically harvested and processed as Spanish-style green olives was assessed. The percentage of olives free of any brown spots ranged between 35-50%, 10-25% and 50-65% for fruit directly processed, storage under nitrogen and coated and storage under nitrogen respectively. Moreover, olives stored in the open air developed brown spots due to the oxidation of oleuropein. By contrast, the anoxic conditions prevented oleuropein from undergoing enzymatic oxidation but not from its enzymatic hydrolysis. Hence, the phenolic derivative HyEDA was formed in olives stored under nitrogen, and this substance was rapidly oxidized in the open air to give rise to brown spots although to a lesser extent in the coated fruit. Therefore, the postharvest storage of coated olives under nitrogen can be a good method to prevent bruise damage in mechanically harvested fruit. PMID:25308641

  11. Design and fabrication of miniaturized PEM fuel cell combined microreactor with self-regulated hydrogen mechanism

    NASA Astrophysics Data System (ADS)

    Balakrishnan, A.; Frei, M.; Kerzenmacher, S.; Reinecke, H.; Mueller, C.

    2015-12-01

    In this work we present the design and fabrication of the miniaturized PEM fuel cell combined microreactor system with hydrogen regulation mechanism and testing of prototype microreactor. The system consists of two components (i) fuel cell component and (ii) microreactor component. The fuel cell component represents the miniaturized PEM fuel cell system (combination of screen printed fuel cell assembly and an on-board hydrogen storage medium). Hydrogen production based on catalytic hydrolysis of chemical hydride takes place in the microreactor component. The self-regulated hydrogen mechanism based on the gaseous hydrogen produced from the catalytic hydrolysis of sodium borohydride (NaBH4) gets accumulated as bubbles at the vicinity of the hydrophobic coated hydrogen exhaust holes. When the built up hydrogen bubbles pressure exceeds the burst pressure at the hydrogen exhaust holes the bubble collapses. This collapse causes a surge of fresh NaBH4 solution onto the catalyst surface leading to the removal of the reaction by-products formed at the active sites of the catalyst. The catalyst used in the system is platinum deposited on a base substrate. Nickel foam, carbon porous medium (CPM) and ceramic plate were selected as candidates for base substrate for developing a robust catalyst surface. For the first time the platinum layer fabricated by pulsed electrodeposition and dealloying (EPDD) technique is used for hydrolysis of NaBH4. The major advantages of such platinum catalyst layers are its high surface area and their mechanical stability. Prototype microreactor system with self-regulated hydrogen mechanism is demonstrated.

  12. Probabilistic Simulation of Combined Thermo-Mechanical Cyclic Fatigue in Composites

    NASA Technical Reports Server (NTRS)

    Chamis, Christos C.

    2010-01-01

    A methodology to compute probabilistically-combined thermo-mechanical fatigue life of polymer matrix laminated composites has been developed and is demonstrated. Matrix degradation effects caused by long-term environmental exposure and mechanical/thermal cyclic loads are accounted for in the simulation process. A unified time-temperature-stress-dependent multifactor-interaction relationship developed at NASA Glenn Research Center has been used to model the degradation/aging of material properties due to cyclic loads. The fast probability-integration method is used to compute probabilistic distribution of response. Sensitivities of fatigue life reliability to uncertainties in the primitive random variables (e.g., constituent properties, fiber volume ratio, void volume ratio, ply thickness, etc.) computed and their significance in the reliability-based design for maximum life is discussed. The effect of variation in the thermal cyclic loads on the fatigue reliability for a (0/+/-45/90)s graphite/epoxy laminate with a ply thickness of 0.127 mm, with respect to impending failure modes has been studied. The results show that, at low mechanical-cyclic loads and low thermal-cyclic amplitudes, fatigue life for 0.999 reliability is most sensitive to matrix compressive strength, matrix modulus, thermal expansion coefficient, and ply thickness. Whereas at high mechanical-cyclic loads and high thermal-cyclic amplitudes, fatigue life at 0.999 reliability is more sensitive to the shear strength of matrix, longitudinal fiber modulus, matrix modulus, and ply thickness.

  13. Probabilistic Simulation of Combined Thermo-Mechanical Cyclic Fatigue in Composites

    NASA Technical Reports Server (NTRS)

    Chamis, Christos C.

    2011-01-01

    A methodology to compute probabilistically-combined thermo-mechanical fatigue life of polymer matrix laminated composites has been developed and is demonstrated. Matrix degradation effects caused by long-term environmental exposure and mechanical/thermal cyclic loads are accounted for in the simulation process. A unified time-temperature-stress-dependent multifactor-interaction relationship developed at NASA Glenn Research Center has been used to model the degradation/aging of material properties due to cyclic loads. The fast probability-integration method is used to compute probabilistic distribution of response. Sensitivities of fatigue life reliability to uncertainties in the primitive random variables (e.g., constituent properties, fiber volume ratio, void volume ratio, ply thickness, etc.) computed and their significance in the reliability-based design for maximum life is discussed. The effect of variation in the thermal cyclic loads on the fatigue reliability for a (0/+/-45/90)s graphite/epoxy laminate with a ply thickness of 0.127 mm, with respect to impending failure modes has been studied. The results show that, at low mechanical-cyclic loads and low thermal-cyclic amplitudes, fatigue life for 0.999 reliability is most sensitive to matrix compressive strength, matrix modulus, thermal expansion coefficient, and ply thickness. Whereas at high mechanical-cyclic loads and high thermal-cyclic amplitudes, fatigue life at 0.999 reliability is more sensitive to the shear strength of matrix, longitudinal fiber modulus, matrix modulus, and ply thickness.

  14. Quinolinic Acid, an endogenous molecule combining excitotoxicity, oxidative stress and other toxic mechanisms.

    PubMed

    Pérez-De La Cruz, Verónica; Carrillo-Mora, Paul; Santamaría, Abel

    2012-01-01

    Quinolinic acid (QUIN), an endogenous metabolite of the kynurenine pathway, is involved in several neurological disorders, including Huntington's disease, Alzheimer's disease, schizophrenia, HIV associated dementia (HAD) etc. QUIN toxicity involves several mechanisms which trigger various metabolic pathways and transcription factors. The primary mechanism exerted by this excitotoxin in the central nervous system (CNS) has been largely related with the overactivation of N-methyl-D-aspartate receptors and increased cytosolic Ca(2+) concentrations, followed by mitochondrial dysfunction, cytochrome c release, ATP exhaustion, free radical formation and oxidative damage. As a result, this toxic pattern is responsible for selective loss of middle size striatal spiny GABAergic neurons and motor alterations in lesioned animals. This toxin has recently gained attention in biomedical research as, in addition to its proven excitotoxic profile, a considerable amount of evidence suggests that oxidative stress and energetic disturbances are major constituents of its toxic pattern in the CNS. Hence, this profile has changed our perception of how QUIN-related disorders combine different toxic mechanisms resulting in brain damage. This review will focus on the description and integration of recent evidence supporting old and suggesting new mechanisms to explain QUIN toxicity.

  15. Quinolinic Acid, an Endogenous Molecule Combining Excitotoxicity, Oxidative Stress and Other Toxic Mechanisms

    PubMed Central

    Pérez-De La Cruz, Verónica; Carrillo-Mora, Paul; Santamaría, Abel

    2012-01-01

    Quinolinic acid (QUIN), an endogenous metabolite of the kynurenine pathway, is involved in several neurological disorders, including Huntington’s disease, Alzheimer’s disease, schizophrenia, HIV associated dementia (HAD) etc. QUIN toxicity involves several mechanisms which trigger various metabolic pathways and transcription factors. The primary mechanism exerted by this excitotoxin in the central nervous system (CNS) has been largely related with the overactivation of N-methyl-D-aspartate receptors and increased cytosolic Ca2+ concentrations, followed by mitochondrial dysfunction, cytochrome c release, ATP exhaustion, free radical formation and oxidative damage. As a result, this toxic pattern is responsible for selective loss of middle size striatal spiny GABAergic neurons and motor alterations in lesioned animals. This toxin has recently gained attention in biomedical research as, in addition to its proven excitotoxic profile, a considerable amount of evidence suggests that oxidative stress and energetic disturbances are major constituents of its toxic pattern in the CNS. Hence, this profile has changed our perception of how QUIN-related disorders combine different toxic mechanisms resulting in brain damage. This review will focus on the description and integration of recent evidence supporting old and suggesting new mechanisms to explain QUIN toxicity. PMID:22408367

  16. Norcantharidin combined with ABT-737 for hepatocellular carcinoma: Therapeutic effects and molecular mechanisms

    PubMed Central

    Ren, Jing; Li, Gang; Zhao, Wen; Lin, Ling; Ye, Tao

    2016-01-01

    AIM: To study the therapeutic effect of norcantharidin (NCTD) combined with ABT-737 on hepatocellular carcinoma cells and the molecular mechanism. METHODS: Two hepatocellular carcinoma (HCC) cell lines, HepG2 and SMMC-7721, were selected. ABT-737 and NCTD were allocated into groups to be used alone or in combination. HepG2 and SMMC-7721 cells were cultured in vitro. Liver cancer cells in the logarithmic phase of growth were vaccinated and cultured to the cell wall stage; these cells were treated for 48 h with different concentrations of NCTD, or ABT-737, or NCTD combined with ABT-737. The cell proliferation inhibition rate was detected by methyl thiazolyl tetrazolium. The expression of Mcl in HCC cells was detected by Western Blotting, and the cells in each group after treatment had apoptosis detected by flow cytometry. The proliferation inhibition rate, the expression of Mcl-1 in cells and the apoptosis inducing effect of treatment were observed in each group, and the effect of NCTD on ABT-737 in the treatment of HCC and its mechanism of action were analyzed. RESULTS: As the concentration of NCTD increased, the cell proliferation inhibition rate gradually decreased; and the treatment effect of ABT-737 1-3 μm combined with NCTD on cell proliferation inhibition was stronger than that of ABT-737 alone. The difference was statistically significant (P < 0.05). In observing the expression of Mcl-1 in cells after the treatment of different concentrations of NCTD, this was partially inhibited after treatment with NCTD 15 μm, and the expression of Mcl-1 was almost undetectable after treatment with NCTD 30 μm and 60 μm. The effect on inducing apoptosis with the treatment of ABT-737 or NCTD alone for 48 h was lower than that of the control group. The difference was not statistically significant (P > 0.05). The effect on inducing apoptosis in HepG2 and SMMC-7721 cells with the treatment of ABT-737 combined with NCTD for 48 h was greater than that of ABT-737 or NCTD alone

  17. Possible Peroxo State of the Dicopper Site of Particulate Methane Monooxygenase from Combined Quantum Mechanics and Molecular Mechanics Calculations.

    PubMed

    Itoyama, Shuhei; Doitomi, Kazuki; Kamachi, Takashi; Shiota, Yoshihito; Yoshizawa, Kazunari

    2016-03-21

    Enzymatic methane hydroxylation is proposed to efficiently occur at the dinuclear copper site of particulate methane monooxygenase (pMMO), which is an integral membrane metalloenzyme in methanotrophic bacteria. The resting state and a possible peroxo state of the dicopper active site of pMMO are discussed by using combined quantum mechanics and molecular mechanics calculations on the basis of reported X-ray crystal structures of the resting state of pMMO by Rosenzweig and co-workers. The dicopper site has a unique structure, in which one copper is coordinated by two histidine imidazoles and another is chelated by a histidine imidazole and primary amine of an N-terminal histidine. The resting state of the dicopper site is assignable to the mixed-valent Cu(I)Cu(II) state from a computed Cu-Cu distance of 2.62 Å from calculations at the B3LYP-D/TZVP level of theory. A μ-η(2):η(2)-peroxo-Cu(II)2 structure similar to those of hemocyanin and tyrosinase is reasonably obtained by using the resting state structure and dioxygen. Computed Cu-Cu and O-O distances are 3.63 and 1.46 Å, respectively, in the open-shell singlet state. Structural features of the dicopper peroxo species of pMMO are compared with those of hemocyanin and tyrosinase and synthetic dicopper model compounds. Optical features of the μ-η(2):η(2)-peroxo-Cu(II)2 state are calculated and analyzed with TD-DFT calculations.

  18. Possible Peroxo State of the Dicopper Site of Particulate Methane Monooxygenase from Combined Quantum Mechanics and Molecular Mechanics Calculations.

    PubMed

    Itoyama, Shuhei; Doitomi, Kazuki; Kamachi, Takashi; Shiota, Yoshihito; Yoshizawa, Kazunari

    2016-03-21

    Enzymatic methane hydroxylation is proposed to efficiently occur at the dinuclear copper site of particulate methane monooxygenase (pMMO), which is an integral membrane metalloenzyme in methanotrophic bacteria. The resting state and a possible peroxo state of the dicopper active site of pMMO are discussed by using combined quantum mechanics and molecular mechanics calculations on the basis of reported X-ray crystal structures of the resting state of pMMO by Rosenzweig and co-workers. The dicopper site has a unique structure, in which one copper is coordinated by two histidine imidazoles and another is chelated by a histidine imidazole and primary amine of an N-terminal histidine. The resting state of the dicopper site is assignable to the mixed-valent Cu(I)Cu(II) state from a computed Cu-Cu distance of 2.62 Å from calculations at the B3LYP-D/TZVP level of theory. A μ-η(2):η(2)-peroxo-Cu(II)2 structure similar to those of hemocyanin and tyrosinase is reasonably obtained by using the resting state structure and dioxygen. Computed Cu-Cu and O-O distances are 3.63 and 1.46 Å, respectively, in the open-shell singlet state. Structural features of the dicopper peroxo species of pMMO are compared with those of hemocyanin and tyrosinase and synthetic dicopper model compounds. Optical features of the μ-η(2):η(2)-peroxo-Cu(II)2 state are calculated and analyzed with TD-DFT calculations. PMID:26918461

  19. Evolution of water sorption in catalyst coated membranes subjected to combined chemical and mechanical degradation.

    PubMed

    Venkatesan, Senthil velan; Lim, Chan; Rogers, Erin; Holdcroft, Steven; Kjeang, Erik

    2015-06-01

    Catalyst coated perfluorosulfonic acid ionomer membranes (CCMs) were subjected to a combined chemical/mechanical accelerated stress test (AST) designed for rapid benchmarking of in situ membrane stability in polymer electrolyte fuel cells. In order to understand the evolution of the ionomer water sorption characteristics during combined chemical/mechanical degradation, CCM samples were periodically extracted from the AST and analyzed for ionomer mass fraction and water sorption properties. In spite of severe fluoride release and membrane thinning, the water uptake per unit mass of the partially degraded CCMs was found to be essentially constant. The mass fraction of ionomer in the CCM samples determined from thermogravimetric analysis (TGA) showed significant material loss throughout the AST process due to ionomer degradation and fluoride release, up to roughly 50% at end-of-life. The effects proceeding at different stages of degradation were therefore more accurately revealed by ionomer mass-normalized data. The water uptake per unit gram of ionomer was shown to increase significantly with degradation, in contrast to the previous results normalized by CCM dry mass. Although increased water sorption may indicate enlarged solvated hydrophilic domains in the membrane, which would be beneficial for enhanced proton mobility, the proton conductivity was found to decrease. This finding suggests that the additional water sorbed in the membrane was not contributing to proton conduction and was therefore likely situated in non-ionic cavities formed through degradation rather than in the ionic clusters.

  20. Gemcitabine/cannabinoid combination triggers autophagy in pancreatic cancer cells through a ROS-mediated mechanism

    PubMed Central

    Donadelli, M; Dando, I; Zaniboni, T; Costanzo, C; Dalla Pozza, E; Scupoli, M T; Scarpa, A; Zappavigna, S; Marra, M; Abbruzzese, A; Bifulco, M; Caraglia, M; Palmieri, M

    2011-01-01

    Gemcitabine (GEM, 2′,2′-difluorodeoxycytidine) is currently used in advanced pancreatic adenocarcinoma, with a response rate of < 20%. The purpose of our work was to improve GEM activity by addition of cannabinoids. Here, we show that GEM induces both cannabinoid receptor-1 (CB1) and cannabinoid receptor-2 (CB2) receptors by an NF-κB-dependent mechanism and that its association with cannabinoids synergistically inhibits pancreatic adenocarcinoma cell growth and increases reactive oxygen species (ROS) induced by single treatments. The antiproliferative synergism is prevented by the radical scavenger N-acetyl--cysteine and by the specific NF-κB inhibitor BAY 11-7085, demonstrating that the induction of ROS by GEM/cannabinoids and of NF-κB by GEM is required for this effect. In addition, we report that neither apoptotic nor cytostatic mechanisms are responsible for the synergistic cell growth inhibition, which is strictly associated with the enhancement of endoplasmic reticulum stress and autophagic cell death. Noteworthy, the antiproliferative synergism is stronger in GEM-resistant pancreatic cancer cell lines compared with GEM-sensitive pancreatic cancer cell lines. The combined treatment strongly inhibits growth of human pancreatic tumor cells xenografted in nude mice without apparent toxic effects. These findings support a key role of the ROS-dependent activation of an autophagic program in the synergistic growth inhibition induced by GEM/cannabinoid combination in human pancreatic cancer cells. PMID:21525939

  1. Gemcitabine/cannabinoid combination triggers autophagy in pancreatic cancer cells through a ROS-mediated mechanism.

    PubMed

    Donadelli, M; Dando, I; Zaniboni, T; Costanzo, C; Dalla Pozza, E; Scupoli, M T; Scarpa, A; Zappavigna, S; Marra, M; Abbruzzese, A; Bifulco, M; Caraglia, M; Palmieri, M

    2011-04-28

    Gemcitabine (GEM, 2',2'-difluorodeoxycytidine) is currently used in advanced pancreatic adenocarcinoma, with a response rate of < 20%. The purpose of our work was to improve GEM activity by addition of cannabinoids. Here, we show that GEM induces both cannabinoid receptor-1 (CB1) and cannabinoid receptor-2 (CB2) receptors by an NF-κB-dependent mechanism and that its association with cannabinoids synergistically inhibits pancreatic adenocarcinoma cell growth and increases reactive oxygen species (ROS) induced by single treatments. The antiproliferative synergism is prevented by the radical scavenger N-acetyl-L-cysteine and by the specific NF-κB inhibitor BAY 11-7085, demonstrating that the induction of ROS by GEM/cannabinoids and of NF-κB by GEM is required for this effect. In addition, we report that neither apoptotic nor cytostatic mechanisms are responsible for the synergistic cell growth inhibition, which is strictly associated with the enhancement of endoplasmic reticulum stress and autophagic cell death. Noteworthy, the antiproliferative synergism is stronger in GEM-resistant pancreatic cancer cell lines compared with GEM-sensitive pancreatic cancer cell lines. The combined treatment strongly inhibits growth of human pancreatic tumor cells xenografted in nude mice without apparent toxic effects. These findings support a key role of the ROS-dependent activation of an autophagic program in the synergistic growth inhibition induced by GEM/cannabinoid combination in human pancreatic cancer cells.

  2. Magnetoelectric coupling of multiferroic composites under combined magnetic and mechanical loadings

    NASA Astrophysics Data System (ADS)

    Fang, F.; Zhou, Y. Y.; Xu, Y. T.; Jing, W. Q.; Yang, W.

    2013-07-01

    Multiferroic composites are of particular interest because of their high magnetoelectric (ME) coupling at room temperature. In multiferroic composites, ME coupling is a strain mediated effect achieved via the interfaces between the magnetic and electrical subsystems through elastic deformation. In this paper, ME coupling of laminate composites is investigated under combined magnetic and mechanical loadings. Three types of laminate composites are used, with piezoelectric phase layers of PZT plates and the magnetic phase layers comprising Terfenol-D, Ni and Metglas, respectively. As the applied compressive stress increases, the ME coefficient (αME) decreases monotonically for Terfenol-D/PZT/Terfenol-D and Metglas/PZT/Metglas, while it slightly increases for Ni/PZT/Ni laminate. To reveal the influence of the magnetic layers on the ME coupling, measurements of magnetostriction under combined magnetic and compressive loadings are carried out for Terfenol-D, Ni and Metglas. Based on the equivalent circuit model, the peak values of the ME coefficient for different compressive stresses are predicted for the laminate composites; these agree well with the experimental data. It is suggested that the compressive stress-induced strain, as well as the magnetostrictive response of the magnetic material, mainly contribute to the mechanical-magnetic-electrical coupling behavior of the multiferroic composites.

  3. Examination of turbulent entrainment-mixing mechanisms using a combined approach

    SciTech Connect

    Lu, C.; Liu, Y.; Niu, S.

    2011-10-01

    Turbulent entrainment-mixing mechanisms are investigated by applying a combined approach to the aircraft measurements of three drizzling and two nondrizzling stratocumulus clouds collected over the U.S. Department of Energy's Atmospheric Radiation Measurement Southern Great Plains site during the March 2000 cloud Intensive Observation Period. Microphysical analysis shows that the inhomogeneous entrainment-mixing process occurs much more frequently than the homogeneous counterpart, and most cases of the inhomogeneous entrainment-mixing process are close to the extreme scenario, having drastically varying cloud droplet concentration but roughly constant volume-mean radius. It is also found that the inhomogeneous entrainment-mixing process can occur both near the cloud top and in the middle level of a cloud, and in both the nondrizzling clouds and nondrizzling legs in the drizzling clouds. A new dimensionless number, the scale number, is introduced as a dynamical measure for different entrainment-mixing processes, with a larger scale number corresponding to a higher degree of homogeneous entrainment mixing. Further empirical analysis shows that the scale number that separates the homogeneous from the inhomogeneous entrainment-mixing process is around 50, and most legs have smaller scale numbers. Thermodynamic analysis shows that sampling average of filament structures finer than the instrumental spatial resolution also contributes to the dominance of inhomogeneous entrainment-mixing mechanism. The combined microphysical-dynamical-thermodynamic analysis sheds new light on developing parameterization of entrainment-mixing processes and their microphysical and radiative effects in large-scale models.

  4. Mechanisms mediating enhanced neutralization efficacy of staphylococcal enterotoxin B by combinations of monoclonal antibodies.

    PubMed

    Dutta, Kaushik; Varshney, Avanish K; Franklin, Matthew C; Goger, Michael; Wang, Xiaobo; Fries, Bettina C

    2015-03-13

    Staphylococcal enterotoxin B (SEB) is a superantigen that cross-links the major histocompatibility complex class II and specific V-β chains of the T-cell receptor, thus forming a ternary complex. Developing neutralizing mAb to disrupt the ternary complex and abrogate the resulting toxicity is a major therapeutic challenge because SEB is effective at very low concentrations. We show that combining two SEB-specific mAbs enhances their efficacy, even though one of the two mAbs by itself has no effect on neutralization. Crystallography was employed for fine-mapping conformational epitopes in binary and ternary complexes between SEB and Fab fragments. NMR spectroscopy was used to validate and identify subtle allosteric changes induced by mAbs binding to SEB. The mapping of epitopes established that a combination of different mAbs can enhance efficacy of mAb-mediated protection from SEB induced lethal shock by two different mechanisms: one mAb mixture promoted clearance of the toxin both in vitro and in vivo by FcR-mediated cross-linking and clearance, whereas the other mAb mixture induced subtle allosteric conformational changes in SEB that perturbed formation of the SEB·T-cell receptor·major histocompatibility complex class II trimer. Finally structural information accurately predicted mAb binding to other superantigens that share conformational epitopes with SEB. Fine mapping of conformational epitopes is a powerful tool to establish the mechanism and optimize the action of synergistic mAb combinations. PMID:25572397

  5. Mechanism of bacterial inactivation by (+)-limonene and its potential use in food preservation combined processes.

    PubMed

    Espina, Laura; Gelaw, Tilahun K; de Lamo-Castellví, Sílvia; Pagán, Rafael; García-Gonzalo, Diego

    2013-01-01

    This work explores the bactericidal effect of (+)-limonene, the major constituent of citrus fruits' essential oils, against E. coli. The degree of E. coli BJ4 inactivation achieved by (+)-limonene was influenced by the pH of the treatment medium, being more bactericidal at pH 4.0 than at pH 7.0. Deletion of rpoS and exposure to a sub-lethal heat or an acid shock did not modify E. coli BJ4 resistance to (+)-limonene. However, exposure to a sub-lethal cold shock decreased its resistance to (+)-limonene. Although no sub-lethal injury was detected in the cell envelopes after exposure to (+)-limonene by the selective-plating technique, the uptake of propidium iodide by inactivated E. coli BJ4 cells pointed out these structures as important targets in the mechanism of action. Attenuated Total Reflectance Infrared Microspectroscopy (ATR-IRMS) allowed identification of altered E. coli BJ4 structures after (+)-limonene treatments as a function of the treatment pH: β-sheet proteins at pH 4.0 and phosphodiester bonds at pH 7.0. The increased sensitivity to (+)-limonene observed at pH 4.0 in an E. coli MC4100 lptD4213 mutant with an increased outer membrane permeability along with the identification of altered β-sheet proteins by ATR-IRMS indicated the importance of this structure in the mechanism of action of (+)-limonene. The study of mechanism of inactivation by (+)-limonene led to the design of a synergistic combined process with heat for the inactivation of the pathogen E. coli O157:H7 in fruit juices. These results show the potential of (+)-limonene in food preservation, either acting alone or in combination with lethal heat treatments.

  6. Mechanism of bacterial inactivation by (+)-limonene and its potential use in food preservation combined processes.

    PubMed

    Espina, Laura; Gelaw, Tilahun K; de Lamo-Castellví, Sílvia; Pagán, Rafael; García-Gonzalo, Diego

    2013-01-01

    This work explores the bactericidal effect of (+)-limonene, the major constituent of citrus fruits' essential oils, against E. coli. The degree of E. coli BJ4 inactivation achieved by (+)-limonene was influenced by the pH of the treatment medium, being more bactericidal at pH 4.0 than at pH 7.0. Deletion of rpoS and exposure to a sub-lethal heat or an acid shock did not modify E. coli BJ4 resistance to (+)-limonene. However, exposure to a sub-lethal cold shock decreased its resistance to (+)-limonene. Although no sub-lethal injury was detected in the cell envelopes after exposure to (+)-limonene by the selective-plating technique, the uptake of propidium iodide by inactivated E. coli BJ4 cells pointed out these structures as important targets in the mechanism of action. Attenuated Total Reflectance Infrared Microspectroscopy (ATR-IRMS) allowed identification of altered E. coli BJ4 structures after (+)-limonene treatments as a function of the treatment pH: β-sheet proteins at pH 4.0 and phosphodiester bonds at pH 7.0. The increased sensitivity to (+)-limonene observed at pH 4.0 in an E. coli MC4100 lptD4213 mutant with an increased outer membrane permeability along with the identification of altered β-sheet proteins by ATR-IRMS indicated the importance of this structure in the mechanism of action of (+)-limonene. The study of mechanism of inactivation by (+)-limonene led to the design of a synergistic combined process with heat for the inactivation of the pathogen E. coli O157:H7 in fruit juices. These results show the potential of (+)-limonene in food preservation, either acting alone or in combination with lethal heat treatments. PMID:23424676

  7. Mechanism of Bacterial Inactivation by (+)-Limonene and Its Potential Use in Food Preservation Combined Processes

    PubMed Central

    Espina, Laura; Gelaw, Tilahun K.; de Lamo-Castellví, Sílvia; Pagán, Rafael; García-Gonzalo, Diego

    2013-01-01

    This work explores the bactericidal effect of (+)-limonene, the major constituent of citrus fruits' essential oils, against E. coli. The degree of E. coli BJ4 inactivation achieved by (+)-limonene was influenced by the pH of the treatment medium, being more bactericidal at pH 4.0 than at pH 7.0. Deletion of rpoS and exposure to a sub-lethal heat or an acid shock did not modify E. coli BJ4 resistance to (+)-limonene. However, exposure to a sub-lethal cold shock decreased its resistance to (+)-limonene. Although no sub-lethal injury was detected in the cell envelopes after exposure to (+)-limonene by the selective-plating technique, the uptake of propidium iodide by inactivated E. coli BJ4 cells pointed out these structures as important targets in the mechanism of action. Attenuated Total Reflectance Infrared Microspectroscopy (ATR-IRMS) allowed identification of altered E. coli BJ4 structures after (+)-limonene treatments as a function of the treatment pH: β-sheet proteins at pH 4.0 and phosphodiester bonds at pH 7.0. The increased sensitivity to (+)-limonene observed at pH 4.0 in an E. coli MC4100 lptD4213 mutant with an increased outer membrane permeability along with the identification of altered β-sheet proteins by ATR-IRMS indicated the importance of this structure in the mechanism of action of (+)-limonene. The study of mechanism of inactivation by (+)-limonene led to the design of a synergistic combined process with heat for the inactivation of the pathogen E. coli O157:H7 in fruit juices. These results show the potential of (+)-limonene in food preservation, either acting alone or in combination with lethal heat treatments. PMID:23424676

  8. Mechanism of red mud combined with Fenton's reagent in sewage sludge conditioning.

    PubMed

    Zhang, Hao; Yang, Jiakuan; Yu, Wenbo; Luo, Sen; Peng, Li; Shen, Xingxing; Shi, Yafei; Zhang, Shinan; Song, Jian; Ye, Nan; Li, Ye; Yang, Changzhu; Liang, Sha

    2014-08-01

    Red mud was evaluated as an alternative skeleton builder combined with Fenton's reagent in sewage sludge conditioning. The results show that red mud combined with Fenton's reagent showed good conditioning capability with the pH of the filtrate close to neutrality, indicating that red mud acted as a neutralizer as well as a skeleton builder when jointly used with Fenton's reagent. Through response surface methodology (RSM), the optimal dosages of Fe(2+), H2O2 and red mud were proposed as 31.9, 33.7 and 275.1 mg/g DS (dry solids), respectively. The mechanism of the composite conditioner could be illuminated as follows: (1) extracellular polymeric substances (EPS), including loosely bound EPS and tightly bound EPS, were degraded into dissolved organics, e.g., proteins and polysaccharides; (2) bound water was released and converted into free water due to the degradation of EPS; and (3) morphology of the conditioned sludge exhibited a porous structure in contrast with the compact structure of raw sludge, and the addition of red mud formed new mineral phases and a rigid lattice structure in sludge, allowing the outflow of free water. Thus, sludge dewatering performance was effectively improved. The economic assessment for a wastewater treatment plant of 370,000 equivalent inhabitants confirms that using red mud conditioning, combined with Fenton's reagent, leads to a saving of approximately 411,000 USD/y or 50.8 USD/t DS comparing with using lime and ordinary Portland cement combined with Fenton's reagent, and approximately 612,000 USD/y or 75.5 USD/t DS comparing with the traditional treatment. PMID:24810740

  9. Mechanically fastened composite laminates subjected to combined bearing-bypass and shear loading

    NASA Technical Reports Server (NTRS)

    Madenci, Erdogan

    1993-01-01

    Bolts and rivets provide a means of load transfer in the construction of aircraft. However, they give rise to stress concentrations and are often the source and location of static and fatigue failures. Furthermore, fastener holes are prone to cracks during take-off and landing. These cracks present the most common origin of structural failures in aircraft. Therefore, accurate determination of the contact stresses associated with such loaded holes in mechanically fastened joints is essential to reliable strength evaluation and failure prediction. As the laminate is subjected to loading, the contact region, whose extent is not known, develops between the fastener and the hole boundary through this contact region, which consists of slip and no-slip zones due to friction. The presence of the unknown contact stress distribution over the contact region between the pin and the composite laminate, material anisotropy, friction between the pin and the laminate, pin-hole clearance, combined bearing-bypass and shear loading, and finite geometry of the laminate result in a complex non-linear problem. In the case of bearing-bypass loading in compression, this non-linear problem is further complicated by the presence of dual contact regions. Previous research concerning the analysis of mechanical joints subjected to combined bearing-bypass and shear loading is non-existent. In the case of bearing-bypass loading only, except for the study conducted by Naik and Crews (1991), others employed the concept of superposition which is not valid for this non-linear problem. Naik and Crews applied a linear finite element analysis with conditions along the pin-hole contact region specified as displacement constraint equations. The major shortcoming of this method is that the variation of the contract region as a function of the applied load should be known a priori. Also, their analysis is limited to symmetric geometry and material systems, and frictionless boundary conditions. Since the

  10. Immuno-pharmacodynamics for evaluating mechanism of action and developing immunotherapy combinations.

    PubMed

    Parchment, Ralph E; Voth, Andrea Regier; Doroshow, James H; Berzofsky, Jay A

    2016-08-01

    Immunotherapy has become a major modality of cancer treatment, with multiple new classes of immunotherapeutics recently entering the clinic and obtaining market approval from regulatory agencies. While the promise of these therapies is great, so is the number of possible combinations not only with each other but also with small molecule therapeutics. Furthermore, the observation of unusual dose-response relationships suggests a critical dependency of drug effectiveness on the dosage regimen (dose and schedule). Clinical pharmacodynamic (PD) biomarkers will be useful endpoints for confirming drug mechanism of action, evaluating combination therapies for synergy or antagonism, and identifying optimal dosage regimens. In contrast to conventional PD in which drug action occurs entirely within a single target cell (ie, is self-contained within the malignant cell), immunotherapy involves a complex mechanism of action with sequential steps that propagate through multiple cell types, both normal and malignant. Its intercellular pharmacology begins with molecular target engagement either on an immune effector cell or a malignant cell, followed by stimulatory biochemical and biological signals in immune effector cells, and then finally ends with activation of cell death mechanisms in malignant cells lying within a certain distance from the activated effector cells (immune cell-tumor cell proximity). Evaluating such "trans-cellular pharmacology," in which different steps of drug action are distributed across multiple cell types, requires novel microscopy and image analysis tools capable of quantifying PD-biomarker responses, mapping the responses onto the cellular geography of the tumor using phenotypic biomarkers to identify specific cell types, and finally analyzing the spatial relationships between biomarkers in the context of each cell's biological role. We have termed this form of nearest neighbor image analysis of drug action "proximity PD microscopy," to indicate the

  11. Combined spectroscopic study on the growth mechanism of Diphosphine-stabilized Gold Nanoclusters

    NASA Astrophysics Data System (ADS)

    Bao, Jie; Yang, Lina; Liu, Wei; Huang, Yuanyuan; Huang, Ting; Cao, Yuanjie; Yao, Tao; Sun, Zhihu; Wei, Shiqiang

    2016-05-01

    The formation process of 1,5-Bis(diphenylphosphino) pentane (L5)-protected Au nanocluster through the reduction of precursor Au2L5Cl2 by borane-tert-butylamine (TBAB) is traced by a combination of time-dependent x-ray/UV-vis absorption spectroscopies and mass spectrometry. It is revealed that the initial generation of dual-core basic unit Au4L5 2Cl is a critical step, which allows for a subsequent size-growth process via incorporation of the existing Au monomer (Au(I)-Cl) or Au2L5 to form Au5L5 2, Au8L5 3Cl, Au10L5 4Cl and finally main Au11L5 4Cl2 This work advances one step further toward understanding the mechanism of formation and growth of diphosphine ligands-protected Au NCs.

  12. On combining Thole's induced point dipole model with fixed charge distributions in molecular mechanics force fields.

    PubMed

    Antila, Hanne S; Salonen, Emppu

    2015-04-15

    The Thole induced point dipole model is combined with three different point charge fitting methods, Merz-Kollman (MK), charges from electrostatic potentials using a grid (CHELPG), and restrained electrostatic potential (RESP), and two multipole algorithms, distributed multipole analysis (DMA) and Gaussian multipole model (GMM), which can be used to describe the electrostatic potential (ESP) around molecules in molecular mechanics force fields. This is done to study how the different methods perform when intramolecular polarizability contributions are self-consistently removed from the fitting done in the force field parametrization. It is demonstrated that the polarizable versions of the partial charge models provide a good compromise between accuracy and computational efficiency in describing the ESP of small organic molecules undergoing conformational changes. For the point charge models, the inclusion of polarizability reduced the the average root mean square error of ESP over the test set by 4-10%.

  13. Antimicrobial Combinations against Pan-Resistant Acinetobacter baumannii Isolates with Different Resistance Mechanisms

    PubMed Central

    Leite, Gleice Cristina; Oliveira, Maura Salaroli; Perdigão-Neto, Lauro Vieira; Rocha, Cristiana Kamia Dias; Guimarães, Thais; Rizek, Camila; Levin, Anna Sara; Costa, Silvia Figueiredo

    2016-01-01

    The study investigated the effect of antibiotic combinations against 20 clinical isolates of A. baumannii (seven colistin-resistant and 13 colistin-susceptible) with different resistance mechanisms. Clinical data, treatment, and patient mortality were evaluated. The following methods were used: MIC, PCRs, and outer membrane protein (OMP) analysis. Synergy was investigated using the checkerboard and time-kill methods. Clonality was evaluated by PFGE. Based on clonality, the whole genome sequence of six A. baumannii isolates was analyzed. All isolates were resistant to meropenem, rifampicin, and fosfomycin. OXA-23 and OXA-143 were the most frequent carbapenemases found. Four isolates showed loss of a 43kDa OMP. The colistin-susceptible isolates belonged to different clones and showed the highest synergistic effect with fosfomycin-amikacin. Among colistin-resistant isolates, the highest synergistic effect was observed with the combinations of colistin-rifampicin followed by colistin-vancomycin. All colistin-resistant isolates harbored blaOXA-23-like and belonged to CC113. Clinical and demographic data were available for 18 of 20 patients. Fourteen received treatment and eight patients died during treatment. The most frequent site of infection was the blood in 13 of 14 patients. Seven patients received vancomycin plus an active drug against A. baumannii; however, mortality did not differ in this group. The synergistic effect was similar for colistin-susceptible isolates of distinct clonal origin presenting with the same resistance mechanism. Overall mortality and death during treatment was high, and despite the high synergism in vitro with vancomycin, death did not differ comparing the use or not of vancomycin plus an active drug against A. baumannii. PMID:26998609

  14. Mechanisms of Action Point Towards Combined PBDE/NDL-PCB Risk Assessment.

    PubMed

    Dingemans, Milou M L; Kock, Marjolijn; van den Berg, Martin

    2016-10-01

    At present, human risk assessment of the structurally similar non-dioxin-like (NDL) PCBs and polybrominated diphenylethers (PBDEs) is done independently for both groups of compounds. There are however obvious similarities between NDL-PCBs and PBDEs with regard to modulation of the intracellular calcium homeostasis (basal calcium levels, voltage-gated calcium channels, calcium uptake, ryanodine receptor) and thyroid hormone (TH) homeostasis (TH levels and transport). which are mechanisms of action related to neurobehavioral effects (spontaneous activity, habituation and learning ability). There also similarities in agonistic interactions with the hepatic nuclear receptors PXR and CAR. Several effects on developmental (reproductive) processes have also been observed, but results were more dispersed and insufficient to compare both groups of compounds. The available mechanistic information is sufficient to warrant a dose addition model for NDL-PCBs and PBDEs, including their hydroxylated metabolites.Although many of the observed effects are similar from a qualitative point of view for both groups, congener or tissue specific differences have also been found. As this is a source of uncertainty in the combined hazard and risk assessment of these compounds, molecular entities involved in the observed mechanisms and adverse outcomes associated with these compounds need to be identified. The systematical generation of (quantitative) structure-activity information for NDL-PCBs and PBDEs on these targets (including potential non-additive effects) will allow a more realistic risk estimation associated with combined exposure to both groups of compounds during early life. Additional validation studies are needed to quantify these uncertainties for risk assessment of NDL-PCBs and PBDEs. PMID:27672163

  15. Mechanisms of Action Point Towards Combined PBDE/NDL-PCB Risk Assessment.

    PubMed

    Dingemans, Milou M L; Kock, Marjolijn; van den Berg, Martin

    2016-10-01

    At present, human risk assessment of the structurally similar non-dioxin-like (NDL) PCBs and polybrominated diphenylethers (PBDEs) is done independently for both groups of compounds. There are however obvious similarities between NDL-PCBs and PBDEs with regard to modulation of the intracellular calcium homeostasis (basal calcium levels, voltage-gated calcium channels, calcium uptake, ryanodine receptor) and thyroid hormone (TH) homeostasis (TH levels and transport). which are mechanisms of action related to neurobehavioral effects (spontaneous activity, habituation and learning ability). There also similarities in agonistic interactions with the hepatic nuclear receptors PXR and CAR. Several effects on developmental (reproductive) processes have also been observed, but results were more dispersed and insufficient to compare both groups of compounds. The available mechanistic information is sufficient to warrant a dose addition model for NDL-PCBs and PBDEs, including their hydroxylated metabolites.Although many of the observed effects are similar from a qualitative point of view for both groups, congener or tissue specific differences have also been found. As this is a source of uncertainty in the combined hazard and risk assessment of these compounds, molecular entities involved in the observed mechanisms and adverse outcomes associated with these compounds need to be identified. The systematical generation of (quantitative) structure-activity information for NDL-PCBs and PBDEs on these targets (including potential non-additive effects) will allow a more realistic risk estimation associated with combined exposure to both groups of compounds during early life. Additional validation studies are needed to quantify these uncertainties for risk assessment of NDL-PCBs and PBDEs.

  16. Analysis of Curved Sandwich Panels Subjected to Combined Temperature Gradient and Mechanical Loads

    NASA Technical Reports Server (NTRS)

    Noor, Ahmed K.; Starnes, James H., Jr.; Peters, Jeanne M.

    1998-01-01

    The results of a detailed study of the nonlinear response of curved sandwich panels with composite face sheets and subjected to a temperature gradient through-the-thickness combined with mechanical loadings are presented. The analysis is based on a first-order shear-deformation Sanders-Budiansky type theory with the effects of large displacements, moderate rotations, transverse shear deformation and laminated anisotropic material behavior included. A mixed formulation is used with the fundamental unknowns consisting of the generalized displacements and the stress resultants of the panel. The nonlinear displacements, strain energy, principal strains, transverse shear stresses, transverse shear strain energy density, and their hierarchical sensitivity coefficients are evaluated. The hierarchical sensitivity coefficients measure the sensitivity of the nonlinear response to variations in the panel parameters, the effective properties of the face sheet layers and the core, and the micromechanical parameters. Numerical results are presented for cylindrical panels subjected to combined pressure loading, edge shortening or extension, edge shear and a temperature gradient through the thickness. The results show the effects of variations in the loading and the panel aspect ratio, on the nonlinear response and its sensitivity to changes in the various panel, effective layer and micromechanical parameters.

  17. Modulation of oligodendrocyte differentiation and maturation by combined biochemical and mechanical cues

    PubMed Central

    Lourenço, Tânia; Paes de Faria, Joana; Bippes, Christian A.; Maia, João; Lopes-da-Silva, José A.; Relvas, João B.; Grãos, Mário

    2016-01-01

    Extracellular matrix (ECM) proteins play a key role during oligodendrogenesis. While fibronectin (FN) is involved in the maintenance and proliferation of oligodendrocyte progenitor cells (OPCs), merosin (MN) promotes differentiation into oligodendrocytes (OLs). Mechanical properties of the ECM also seem to affect OL differentiation, hence this study aimed to clarify the impact of combined biophysical and biochemical elements during oligodendrocyte differentiation and maturation using synthetic elastic polymeric ECM-like substrates. CG-4 cells presented OPC- or OL-like morphology in response to brain-compliant substrates functionalised with FN or MN, respectively. The expression of the differentiation and maturation markers myelin basic protein — MBP — and proteolipid protein — PLP — (respectively) by primary rat oligodendrocytes was enhanced in presence of MN, but only on brain-compliant conditions, considering the distribution (MBP) or amount (PLP) of the protein. It was also observed that maturation of OLs was attained earlier (by assessing PLP expression) by cells differentiated on MN-functionalised brain-compliant substrates than on standard culture conditions. Moreover, the combination of MN and substrate compliance enhanced the maturation and morphological complexity of OLs. Considering the distinct degrees of stiffness tested ranging within those of the central nervous system, our results indicate that 6.5 kPa is the most suitable rigidity for oligodendrocyte differentiation. PMID:26879561

  18. Bacterial radiosensitization by using radiation processing in combination with essential oil: Mechanism of action

    NASA Astrophysics Data System (ADS)

    Lacroix, Monique; Caillet, Stéphane; Shareck, Francois

    2009-07-01

    Spice extracts under the form of essential oils were tested for their efficiency to increase the relative radiosensitivity of Listeria monocytogenes and Escherichia coli O157H7 in culture media. The two pathogens were treated by gamma-irradiation alone or in combination with oregano essential oil to evaluate their mechanism of action. The membrane murein composition, and the intracellular and extracellular concentration of ATP was determined. The bacterial strains were treated with two irradiation doses: 1.2 kGy to induce cell damage and 3.5 kGy to cause cell death for L. monocytogenes. A dose of 0.4 kGy to induce cell damages, 1.1 kGy to obtain viable but nonculturable (VBNC) state and 1.3 kGy to obtain a lethal dose was also applied on E. coli O157H7. Oregano essential oil was used at 0.020% and 0.025% (w/v), which is the minimum inhibitory concentration (MIC) for L. monocytogenes. For E. coli O157H7, a concentration of 0.006% and 0.025% (w/v) which is the minimum inhibitory concentration was applied. The use of essential oils in combination with irradiation has permitted an increase of the bacterial radiosensitization by more than 3.1 times. All treatments had also a significant effect ( p⩽0.05) on the murein composition, although some muropeptides did not seem to be affected by the treatment. Each treatment influenced differently the relative percentage and number of muropeptides. There was a significant ( p⩽0.05) correlation between the reduction of intracellular ATP and increase in extracellular ATP following treatment of the cells with oregano oil. The reduction of intracellular ATP was even more important when essential oil was combined with irradiation, but irradiation of L. monocytogenes alone induced a significant decrease ( p⩽0.05) of the internal ATP without affecting the external ATP.

  19. [Mechanism of action of combined extremely weak magnetic field on aqueous solution of amino acid].

    PubMed

    Zhadin, M N; Bakharev, B V; Bobkova, N V

    2014-01-01

    The fundamental physical mechanisms of resonance action of an extremely weak (40 nT) alternating magnetic field at the cyclotron frequency combined with a weak (40 μT) static magnetic field, on living systems are analyzed in the present work. The experimental effects of such sort of magnetic fields were described in different papers: the very narrow resonant peaks in electrical conductivity of the aqueous solutions in the in vitro experiments and the biomedical in vivo effects on living animals of magnetic fields with frequencies tuned to some amino acids. The existing experimental in vitro data had a good repeatability in different laboratories and countries. Unfortunately, for free ions such sort of effects are absolutely impossible because the dimensions of an ion rotation radius should be measured by meters at room temperature and at very low static magnetic fields used in all the above experiments. Even for bound ions these effects should be also absolutely impossible from the positions of classic physics because of rather high viscosity of biological liquid media (blood plasma, cerebrospinal liquid, cytoplasm). Only modern quantum electrodynamics of condensed media opens the new ways for solving these problems. The proposed article is devoted to analysis of quantum mechanisms of these effects. PMID:25707253

  20. Characterization of the mechanical properties of skin by inverse analysis combined with the indentation test.

    PubMed

    Delalleau, Alexandre; Josse, Gwendal; Lagarde, Jean-Michel; Zahouani, Hassan; Bergheau, Jean-Michel

    2006-01-01

    This study proposes a new method to determine the mechanical properties of human skin by the use of the indentation test [Pailler-Mattei, 2004. Caractérisation mécanique et tribologique de la peau humaine in vivo, Ph.D. Thesis, ECL-no. 2004-31; Pailler-Mattei, Zahouani, 2004. Journal of Adhesion Science and Technology 18, 1739-1758]. The principle of the measurements consists in applying an in vivo compressive stress [Zhang et al., 1994. Proceedings of the Institution of Mechanical Engineers 208, 217-222; Bosboom et al., 2001. Journal of Biomechanics 34, 1365-1368; Oomens et al., 1984. Selected Proceedings of Meetings of European Society of Biomechanics, pp. 227-232; Oomens et al., 1987. Journal of Biomechanics 20(9), 877-885] on the skin tissue of an individual's forearm. These measurements show an increase in the normal contact force as a function of the indentation depth. The interpretation of such results usually requires a long and tedious phenomenological study. We propose a new method to determine the mechanical parameters which control the response of skin tissue. This method is threefold: experimental, numerical, and comparative. It consists combining experimental results with a numerical finite elements model in order to find out the required parameters. This process uses a scheme of extended Kalman filters (EKF) [Gu et al., 2003. Materials Science and Engineering A345, 223-233; Nakamura et al., 2000. Acta Mater 48, 4293-4306; Leustean and Rosu, 2003. Certifying Kalman filters. RIACS Technical Report 03.02, 27pp. http://gureni.cs.uiuc.edu/~grosu/download/luta + leo.pdf; Welch and Bishop, An introduction to Kalman filter, University of North Carolina at Chapel Hill, 16p. http://www.cs.unc.edu/~welch/kalman/]. The first results presented in this study correspond to a simplified numerical modeling of the global system. The skin is assumed to be a semi-infinite layer with an isotropic linear elastic mechanical behavior [Zhang et al., 1994. Proceedings of

  1. Characterization of the mechanical properties of skin by inverse analysis combined with the indentation test.

    PubMed

    Delalleau, Alexandre; Josse, Gwendal; Lagarde, Jean-Michel; Zahouani, Hassan; Bergheau, Jean-Michel

    2006-01-01

    This study proposes a new method to determine the mechanical properties of human skin by the use of the indentation test [Pailler-Mattei, 2004. Caractérisation mécanique et tribologique de la peau humaine in vivo, Ph.D. Thesis, ECL-no. 2004-31; Pailler-Mattei, Zahouani, 2004. Journal of Adhesion Science and Technology 18, 1739-1758]. The principle of the measurements consists in applying an in vivo compressive stress [Zhang et al., 1994. Proceedings of the Institution of Mechanical Engineers 208, 217-222; Bosboom et al., 2001. Journal of Biomechanics 34, 1365-1368; Oomens et al., 1984. Selected Proceedings of Meetings of European Society of Biomechanics, pp. 227-232; Oomens et al., 1987. Journal of Biomechanics 20(9), 877-885] on the skin tissue of an individual's forearm. These measurements show an increase in the normal contact force as a function of the indentation depth. The interpretation of such results usually requires a long and tedious phenomenological study. We propose a new method to determine the mechanical parameters which control the response of skin tissue. This method is threefold: experimental, numerical, and comparative. It consists combining experimental results with a numerical finite elements model in order to find out the required parameters. This process uses a scheme of extended Kalman filters (EKF) [Gu et al., 2003. Materials Science and Engineering A345, 223-233; Nakamura et al., 2000. Acta Mater 48, 4293-4306; Leustean and Rosu, 2003. Certifying Kalman filters. RIACS Technical Report 03.02, 27pp. http://gureni.cs.uiuc.edu/~grosu/download/luta + leo.pdf; Welch and Bishop, An introduction to Kalman filter, University of North Carolina at Chapel Hill, 16p. http://www.cs.unc.edu/~welch/kalman/]. The first results presented in this study correspond to a simplified numerical modeling of the global system. The skin is assumed to be a semi-infinite layer with an isotropic linear elastic mechanical behavior [Zhang et al., 1994. Proceedings of

  2. Therapeutical effects and mechanism of salubrinal combined with ulinastatin on treating paraquat poisoning.

    PubMed

    Guo, Hua; Jiang, Chao; Sun, Xiaomin

    2014-12-01

    To explore therapeutic effects and underlying mechanism of Salubrinal combined with Ulinastatin (UTI) on acute Paraquat (PQ) poisoning. Four hundred rats were randomly allocated into UTI group, SAL group, SAL + UTI and control group according to random number table with 100 rats in each group. Acute PQ poisoning models were established, and all rats received UTI, Salubrinal, SAL + UTI and normal saline injection, respectively. Afterward, we analyzed the change of lung tissue and explored the mechanism. Acute PQ poisoning caused significantly damage in rat lung tissue structure, and UTI could effectively repair lung tissue damage. Salubrinal suppressed hemorrhage and fibrosis, but promoted inflammatory infiltration. In contrast, UTI + Salubrinal suppressed hemorrhage, fibrosis and inflammatory infiltration, but could not improve lung tissue damage. Expression of LC3 and Bcl-2 showed statistically significant difference among different groups (p < 0.05). LC3 and Bcl-2 levels in UTI group were much higher than in the other groups, and LC3 and Bcl-2 levels in UTI + SAL group was second higher. LC expression in SAL group was lower than in UTI group and UTI + SAL group with Bcl-2 in control group significantly lower than in the other groups (p < 0.05). Expression of Caspase-3 and Bcl-2/Bax in lung tissue in different groups had statistically significant difference (p < 0.05). Caspase-3 in UTI group was lower than in the other groups; however, Bcl-2/Bax in UTI group was higher than in the other groups (p < 0.05). Acute PQ poisoning can cause endoplasmic reticulum stress-autophagy in rat, and UTI can increase Bcl-2 expression, decrease Caspase-3, which can inhibit progress of lung injury by suppressing apoptosis and exert good therapeutic effects. Although salubrinal has marked effects on protecting lung tissue, it can increase Bcl-2 expression, which is not beneficial to lung tissue protection. The underlying mechanism still needs further exploration.

  3. Therapeutical effects and mechanism of salubrinal combined with ulinastatin on treating paraquat poisoning.

    PubMed

    Guo, Hua; Jiang, Chao; Sun, Xiaomin

    2014-12-01

    To explore therapeutic effects and underlying mechanism of Salubrinal combined with Ulinastatin (UTI) on acute Paraquat (PQ) poisoning. Four hundred rats were randomly allocated into UTI group, SAL group, SAL + UTI and control group according to random number table with 100 rats in each group. Acute PQ poisoning models were established, and all rats received UTI, Salubrinal, SAL + UTI and normal saline injection, respectively. Afterward, we analyzed the change of lung tissue and explored the mechanism. Acute PQ poisoning caused significantly damage in rat lung tissue structure, and UTI could effectively repair lung tissue damage. Salubrinal suppressed hemorrhage and fibrosis, but promoted inflammatory infiltration. In contrast, UTI + Salubrinal suppressed hemorrhage, fibrosis and inflammatory infiltration, but could not improve lung tissue damage. Expression of LC3 and Bcl-2 showed statistically significant difference among different groups (p < 0.05). LC3 and Bcl-2 levels in UTI group were much higher than in the other groups, and LC3 and Bcl-2 levels in UTI + SAL group was second higher. LC expression in SAL group was lower than in UTI group and UTI + SAL group with Bcl-2 in control group significantly lower than in the other groups (p < 0.05). Expression of Caspase-3 and Bcl-2/Bax in lung tissue in different groups had statistically significant difference (p < 0.05). Caspase-3 in UTI group was lower than in the other groups; however, Bcl-2/Bax in UTI group was higher than in the other groups (p < 0.05). Acute PQ poisoning can cause endoplasmic reticulum stress-autophagy in rat, and UTI can increase Bcl-2 expression, decrease Caspase-3, which can inhibit progress of lung injury by suppressing apoptosis and exert good therapeutic effects. Although salubrinal has marked effects on protecting lung tissue, it can increase Bcl-2 expression, which is not beneficial to lung tissue protection. The underlying mechanism still needs further exploration. PMID:25030410

  4. Combined exposure to big endothelin-1 and mechanical loading in bovine sternal cores promotes osteogenesis.

    PubMed

    Meyer, Luisa A; Johnson, Michael G; Cullen, Diane M; Vivanco, Juan F; Blank, Robert D; Ploeg, Heidi-Lynn; Smith, Everett L

    2016-04-01

    , 19 and 23. The data suggest that combined exposure to big ET1 and mechanical loading results in increased osteogenesis as measured in biomechanical, histomorphometric and biochemical responses. PMID:26855374

  5. Opioid Mechanism Involvement in the Synergism Produced by the Combination of Diclofenac and Caffeine in the Formalin Model

    PubMed Central

    Flores-Ramos, José María; Díaz-Reval, M. Irene

    2013-01-01

    Analgesics can be administered in combination with caffeine for improved analgesic effectiveness in a process known as synergism. The mechanisms by which these combinations produce synergism are not yet fully understood. The aim of this study was to analyze whether the administration of diclofenac combined with caffeine produced antinociceptive synergism and whether opioid mechanisms played a role in this event. The formalin model was used to evaluate the antinociception produced by the oral administration of diclofenac, caffeine, or their combination. Opioid involvement was analyzed through intracerebroventricular (i.c.v.) administration of naloxone followed by the oral administration of the study drugs. Diclofenac presented a dose-dependent effect, with a mean effective dose (ED50) of 6.7 mg/kg. Caffeine presented an analgesic effect with a 17–36% range. The combination of subeffective doses of each of the two drugs presented the greatest synergism with an effect of 57.7 ± 5.6%. The maximal antinociceptive effect was obtained with the combination of 10.0 mg/kg diclofenac and 1.0 mg/kg of caffeine, with an effect of 76.7 ± 5.6%. The i.c.v. administration of naloxone inhibited the effect of diclofenac, both separately and combined. In conclusion, caffeine produces antinociceptive synergism when administered in combination with diclofenac, and this synergism is partially mediated by opioid mechanisms at the central level. PMID:27335871

  6. Incidence and mechanisms of resistance to the combination of amoxicillin and clavulanic acid in Escherichia coli.

    PubMed Central

    Stapleton, P; Wu, P J; King, A; Shannon, K; French, G; Phillips, I

    1995-01-01

    Among Escherichia coli organisms isolated at St. Thomas's Hospital during the years 1990 to 1994, the frequency of resistance to amoxicillin-clavulanic acid (tested by disk diffusion in a ratio of 2:1) remained constant at about 5% of patient isolates (10 to 15% of the 41 to 45% that were amoxicillin resistant). Mechanisms of increased resistance were determined for 72 consecutively collected such amoxicillin-clavulanic acid-resistant isolates. MICs of the combination were 16-8 micrograms/ml for 51 (71%) of these and > or = 32-16 micrograms/ml for the remainder. The predominant mechanism was hyperproduction of enzymes isoelectrically cofocusing with TEM-1 (beta-lactamase activities, > 200 nmol of nitrocefin hydrolyzed per min per mg of protein) which was found in 44 isolates (61%); two isolates produced smaller amounts (approximately 150 nmol/min/mg) of such enzymes, and two isolates hyperproduced enzymes cofocusing with TEM-2. Eleven isolates produced enzymes cofocusing with OXA-1 beta-lactamase, which has previously been associated with resistance to amoxicillin-clavulanic acid. Ten isolates produced increased amounts of chromosomal beta-lactamase, and four of these additionally produced TEM-1 or TEM-2. Three isolates produced inhibitor-resistant TEM-group enzymes. In one of the enzymes (pI, 5.4), the amino acid sequence change was Met-67-->Val, and thus the enzyme is identical to TEM-34. Another (pI, 5.4) had the substitution Met-67-->Ile and is identical to IRT-I67, which we propose now be given the designation TEM-40. The third (pI, 5.2) had the substitution Arg-241-->Thr; this enzyme has not been reported previously and should be called TEM-41. The rarity and diversity of inhibitor-resistant TEM-group enzymes suggest that they are the result of spontaneous mutations that have not yet spread. PMID:8585729

  7. Cardiopulmonary bypass (CPB) has no significant impact on survival in patients undergoing nephrectomy and level III-IV inferior vena cava thrombectomy; a multi-institutional analysis

    PubMed Central

    Dall'Era, Marc A.; Durbin-Johnson, Blythe; Carballido, Joaquín A.; Chandrasekar, Thenappan; Chromecki, Thomas; Ciancio, Gaetano; Daneshmand, Siamak; Gontero, Paolo; Gonzalez, Javier; Haferkamp, Axel; Hohenfellner, Markus; Huang, William C.; Espinós, Estefania Linares; Mandel, Philipp; Martinez-Salamanca, Juan I.; Master, Viraj A.; McKiernan, James M.; Montorsi, Francesco; Novara, Giacomo; Pahernik, Sascha; Palou, Juan; Pruthi, Raj S.; Rodriguez-Faba, Oscar; Russo, Paul; Scherr, Douglas S.; Shariat, Shahrokh F.; Spahn, Martin; Terrone, Carlo; Vergho, Daniel; Wallen, Eric M.; Xylinas, Evanguelos; Zigeuner, Richard; Libertino, John A.; Evans, Christopher P.

    2016-01-01

    Purpose The impact of cardiopulmonary bypass (CPB) usage in level III-IV tumor thrombectomy on surgical and oncologic outcomes is unknown. We sought to determine the impact of cardiopulmonary bypass (CPB) on overall and cancer specific survival, as well as surgical complication rates, and immediate outcomes in patients undergoing nephrectomy and level III-IV tumor thrombectomy with or without CPB. Patients and Methods We retrospectively analyzed 362 patients with RCC and with level III or IV tumor thrombus from 1992 to 2012 in 22 US and European centers. Cox proportional hazards models were used to compare overall and cancer-specific survival between patients with and without CPB. Perioperative mortality and complications rates were assessed using logistic regression analyses. Results The median overall survival was 24.6 months in non-CPB patients and 26.6 months in CPB patients. Overall survival and cancer-specific survival (CSS) did not differ significantly in both groups, neither in univariate analysis nor when adjusting for known risk factors. In multivariate analysis, no significant differences were seen in hospital LOS, Clavien 1-4 complication rate, intraoperative or 30 day mortality, and CSS between both groups. Limitations include the retrospective nature of the study. Conclusions In our multi-institutional analysis, the use of cardiopulmonary bypass did not significantly impact cancer specific survival or overall survival in patients undergoing nephrectomy and level III or IV tumor thrombectomy. Neither approach was independently associated with increased mortality in the multivariate analysis. Higher surgical complications were not independently associated with the use of CPB. PMID:25797392

  8. Electrostatic vibration energy harvester with combined effect of electrical nonlinearities and mechanical impact

    NASA Astrophysics Data System (ADS)

    Basset, P.; Galayko, D.; Cottone, F.; Guillemet, R.; Blokhina, E.; Marty, F.; Bourouina, T.

    2014-03-01

    This paper presents an advanced study including the design, characterization and theoretical analysis of a capacitive vibration energy harvester. Although based on a resonant electromechanical device, it is intended for operation in a wide frequency band due to the combination of stop-end effects and a strong biasing electrical field. The electrostatic transducer has an interdigited comb geometry with in-plane motion, and is obtained through a simple batch process using two masks. A continuous conditioning circuit is used for the characterization of the transducer. A nonlinear model of the coupled system ‘transduce-conditioning circuit’ is presented and analyzed employing two different semi-analytical techniques together with precise numerical modelling. Experimental results are in good agreement with results obtained from numerical modelling. With the 1 g amplitude of harmonic external acceleration at atmospheric pressure, the system transducer-conditioning circuit has a half-power bandwidth of more than 30% and converts more than 2 µW of the power of input mechanical vibrations over the range of 140 and 160 Hz. The harvester has also been characterized under stochastic noise-like input vibrations.

  9. Combined decellularisation and dehydration improves the mechanical properties of tissue-engineered sinews

    PubMed Central

    Lebled, Claire; Grover, Liam M

    2014-01-01

    Novel sources of replacement sinews are needed to repair damaged tissue after injury. The current methods of repair ultilise autografts, allografts or xenografts, although each method has distinct disadvantages that limit their success. Decellularisation of harvested tissues has been previously investigated for sinew repair with the long-term aim of repopulating the structure with autologous cells. Although this procedure shows promise, the demand for donor scaffolds will always outweigh supply. Here, we report the fabrication of fibrin-based tissue-engineered sinews, which can be decellularised, dehydrated and stored. The sinews may then be rehydrated and repopulated with an autologous cell population. In addition to enabling production of patient-specific implants, interestingly, the process of combined decellularisation, dehydration and rehydration enhanced the mechanical properties of the sinew. The treated sinews exhibited a 2.6-fold increase in maximum load and 8-fold increase in ultimate tensile strength when compared with the control group (p < 0.05 in both cases). PMID:24904729

  10. Unravelling the mechanism of glycerol hydrogenolysis over rhodium catalyst through combined experimental-theoretical investigations.

    PubMed

    Auneau, Florian; Michel, Carine; Delbecq, Françoise; Pinel, Catherine; Sautet, Philippe

    2011-12-01

    We report herein a detailed and accurate study of the mechanism of rhodium-catalysed conversion of glycerol into 1,2-propanediol and lactic acid. The first step of the reaction is particularly debated, as it can be either dehydration or dehydrogenation. It is expected that these elementary reactions can be influenced by pH variations and by the nature of the gas phase. These parameters were consequently investigated experimentally. On the other hand, there was a lack of knowledge about the behaviour of glycerol at the surface of the metallic catalyst. A theoretical approach on a model Rh(111) surface was thus implemented in the framework of density functional theory (DFT) to describe the above-mentioned elementary reactions and to calculate the corresponding transition states. The combination of experiment and theory shows that the dehydrogenation into glyceraldehyde is the first step for the glycerol transformation on the Rh/C catalyst in basic media under He or H(2) atmosphere. PMID:22069214

  11. The neural dynamic mechanisms of asymmetric switch costs in a combined Stroop-task-switching paradigm.

    PubMed

    Wu, Shanshan; Hitchman, Glenn; Tan, Jinfeng; Zhao, Yuanfang; Tang, Dandan; Wang, Lijun; Chen, Antao

    2015-01-01

    Switch costs have been constantly found asymmetrical when switching between two tasks of unequal dominance. We used a combined Stroop-task-switching paradigm and recorded electroencephalographic (EEG) signals to explore the neural mechanism underlying the phenomenon of asymmetrical switch costs. The results revealed that a fronto-central N2 component demonstrated greater negativity in word switch (cW) trials relative to word repeat (wW) trials, and both First P3 and P3b components over the parieto-central region exhibited greater positivity in color switch (wC) trials relative to color repeat (cC) trials, whereas a contrasting switch-related fronto-central SP effect was found to have an opposite pattern for each task. Moreover, the time-frequency analysis showed a right-frontal lower alpha band (9-11 Hz) modulation in the word task, whereas a fronto-central upper alpha band (11-13 Hz) modulation was exclusively found in the color task. These results provide evidence for dissociable neural processes, which are related to inhibitory control and endogenous control, contributing to the generation of asymmetrical switch costs. PMID:25989933

  12. Angular approach combined to mechanical model for tool breakage detection by eddy current sensors

    NASA Astrophysics Data System (ADS)

    Ritou, M.; Garnier, S.; Furet, B.; Hascoet, J. Y.

    2014-02-01

    The paper presents a new complete approach for Tool Condition Monitoring (TCM) in milling. The aim is the early detection of small damages so that catastrophic tool failures are prevented. A versatile in-process monitoring system is introduced for reliability concerns. The tool condition is determined by estimates of the radial eccentricity of the teeth. An adequate criterion is proposed combining mechanical model of milling and angular approach.Then, a new solution is proposed for the estimate of cutting force using eddy current sensors implemented close to spindle nose. Signals are analysed in the angular domain, notably by synchronous averaging technique. Phase shifts induced by changes of machining direction are compensated. Results are compared with cutting forces measured with a dynamometer table.The proposed method is implemented in an industrial case of pocket machining operation. One of the cutting edges has been slightly damaged during the machining, as shown by a direct measurement of the tool. A control chart is established with the estimates of cutter eccentricity obtained during the machining from the eddy current sensors signals. Efficiency and reliability of the method is demonstrated by a successful detection of the damage.

  13. Enhancing combined biological nitrogen and phosphorus removal from wastewater by applying mechanically disintegrated excess sludge.

    PubMed

    Zubrowska-Sudol, Monika; Walczak, Justyna

    2015-06-01

    The goal of the study was to evaluate the possibility of applying disintegrated excess sludge as a source of organic carbon to enhance biological nitrogen and phosphorus removal. The experiment, performed in a sequencing batch reactor, consisted of two two-month series, without and with applying mechanically disintegrated excess sludge, respectively. The effects on carbon, nitrogen and phosphorus removal were observed. It was shown that the method allows enhancement of combined nitrogen and phosphorus removal. After using disintegrated sludge, denitrification effectiveness increased from 49.2 ± 6.8% to 76.2 ± 2.3%, which resulted in a decline in the NOx-N concentration in the effluent from the SBR by an average of 21.4 mg NOx-N/L. Effectiveness of biological phosphorus removal increased from 28.1 ± 11.3% to 96.2 ± 2.5%, thus resulting in a drop in the [Formula: see text] concentration in the effluent by, on average, 6.05 mg PO4(3-)-P/L. The application of disintegrated sludge did not deteriorate effluent quality in terms of COD and NH4(+)-N. The concentration of NH4(+)-N in both series averaged 0.16 ± 0.11 mg NH4(+)-N/L, and the concentration of COD was 15.36 ± 3.54 mg O2/L.

  14. Synaptic mechanisms shaping delay-tuned combination-sensitivity in the auditory thalamus of mustached bats.

    PubMed

    Butman, John A; Suga, Nobuo

    2016-01-01

    For the processing of target-distance information, delay-tuned auditory neurons of the mustached bat show facilitative responses to a combination of signal elements of a biosonar pulse-echo pair with a specific echo delay. They are initially produced in the inferior colliculus by facilitative responses based on the coincidence of the rebound response following glycinergic inhibition to the first harmonic of the pulse and a short-latency response to the 2nd-4th harmonics of its echo. Here, we report that further facilitative responses to pulse-echo pairs of thalamic delay-tuned neurons are mediated by glutamate receptors (NMDA and non-NMDA receptors), and that GABAergic inhibition shortens the duration of facilitative responses mediated by NMDA-receptors, without changing the delay tuning of thalamic delay-tuned neurons. Different from collicular delay-tuned neurons, thalamic ones respond much more to pulse-echo pairs than individual signal elements. The neural mechanisms involved in shaping thalamic delay-tuning support a model of hierarchical signal processing in the auditory system. PMID:26519094

  15. Enhancing combined biological nitrogen and phosphorus removal from wastewater by applying mechanically disintegrated excess sludge.

    PubMed

    Zubrowska-Sudol, Monika; Walczak, Justyna

    2015-06-01

    The goal of the study was to evaluate the possibility of applying disintegrated excess sludge as a source of organic carbon to enhance biological nitrogen and phosphorus removal. The experiment, performed in a sequencing batch reactor, consisted of two two-month series, without and with applying mechanically disintegrated excess sludge, respectively. The effects on carbon, nitrogen and phosphorus removal were observed. It was shown that the method allows enhancement of combined nitrogen and phosphorus removal. After using disintegrated sludge, denitrification effectiveness increased from 49.2 ± 6.8% to 76.2 ± 2.3%, which resulted in a decline in the NOx-N concentration in the effluent from the SBR by an average of 21.4 mg NOx-N/L. Effectiveness of biological phosphorus removal increased from 28.1 ± 11.3% to 96.2 ± 2.5%, thus resulting in a drop in the [Formula: see text] concentration in the effluent by, on average, 6.05 mg PO4(3-)-P/L. The application of disintegrated sludge did not deteriorate effluent quality in terms of COD and NH4(+)-N. The concentration of NH4(+)-N in both series averaged 0.16 ± 0.11 mg NH4(+)-N/L, and the concentration of COD was 15.36 ± 3.54 mg O2/L. PMID:25776916

  16. Neural network approach for a combined performance and mechanical health monitoring of a gas turbine engine

    NASA Astrophysics Data System (ADS)

    Barad, Sanjay G.; P. V., Ramaiah; R. K., Giridhar; Krishnaiah, G.

    2012-02-01

    Traditionally independent diagnostics methods were employed for health monitoring of system. These exhibited an overall satisfactory performance, but with a limited effectiveness range. A discipline that has emerged in recent years is that of an information (or data) fusion, which allows interweaving of different methods with different effectiveness ranges, to produce a wider and more reliable coverage of diagnosis. It is a multidisciplinary domain wherein, data from the various domain is blended together to arrive at a more reliable monitoring. The present paper brings out a Neural Network (NN) based approach for executing this task of combined health monitoring viz. mechanical and performance, with an example case study pertaining to a developmental power turbine. The various parameters used along with the trending methodologies both for steady state and transient operations are brought out. In addition, the influences of various parameters that can lead to deviations in the response are also discussed. The whole process of executing this task is put forward in a rather simple manner. The results accrued have been well corroborated with the findings on dismantling of the turbine.

  17. Heat flux reduction mechanism induced by a combinational opposing jet and cavity concept in supersonic flows

    NASA Astrophysics Data System (ADS)

    Huang, Wei; Jiang, Yan-ping; Yan, Li; Liu, Jun

    2016-04-01

    The thermal protection on the surface of hypersonic vehicles attracts an increasing attention worldwide, especially when the vehicle enters the atmosphere at high speed. In the current study, the Reynolds-averaged Navier-Stokes (RANS) equations coupled with the Menter's shear stress transport (SST) model have been employed to investigate the heat flux reduction mechanism induced by the variations of the cavity configuration, the jet pressure ratio and the injectant molecular weight in the combinational opposing jet and cavity concept. The length of the cavity is set to be 6 mm, 8 mm and 10 mm in order to make sure that the cavity configuration is the "open" cavity, and the jet pressure ratio is set to be 0.4, 0.6 and 0.8 in order to make sure that the flow field is steady. The injectant is set to be nitrogen and helium. The obtained results show that the aft angle of the cavity only has a slight impact on the heat flux reduction, and the heat flux peak decreases with the decrease of the length of the cavity. The design of the thermal protection system for the hypersonic blunt body is a multi-objective design exploration problem, and the heat flux distribution depends on the jet pressure ratio, the aft wall of the cavity and the injectant molecular weight. The heat flux peak decreases with the increase of the jet pressure ratio when the aft angle of the cavity is large enough, and this value is 45°.

  18. The neural dynamic mechanisms of asymmetric switch costs in a combined Stroop-task-switching paradigm.

    PubMed

    Wu, Shanshan; Hitchman, Glenn; Tan, Jinfeng; Zhao, Yuanfang; Tang, Dandan; Wang, Lijun; Chen, Antao

    2015-05-20

    Switch costs have been constantly found asymmetrical when switching between two tasks of unequal dominance. We used a combined Stroop-task-switching paradigm and recorded electroencephalographic (EEG) signals to explore the neural mechanism underlying the phenomenon of asymmetrical switch costs. The results revealed that a fronto-central N2 component demonstrated greater negativity in word switch (cW) trials relative to word repeat (wW) trials, and both First P3 and P3b components over the parieto-central region exhibited greater positivity in color switch (wC) trials relative to color repeat (cC) trials, whereas a contrasting switch-related fronto-central SP effect was found to have an opposite pattern for each task. Moreover, the time-frequency analysis showed a right-frontal lower alpha band (9-11 Hz) modulation in the word task, whereas a fronto-central upper alpha band (11-13 Hz) modulation was exclusively found in the color task. These results provide evidence for dissociable neural processes, which are related to inhibitory control and endogenous control, contributing to the generation of asymmetrical switch costs.

  19. [Mechanism and kinetics of phenol degradation by TiO2 photocatalytic combined technologies].

    PubMed

    Zhang, Yi; Huang, Ruo-Nan; Wang, Xiao-Min; Wang, Qi; Cong, Yan-Qing

    2013-02-01

    The combination H2O2, or electrical catalytic (EC) system with TiO2 photbcatalytic system for phenol degradation was investigated. The catalytic systems of TiO2/UV, H2O2/UV, TiO2/UV/H2O2 and TiO2/UV/EC were compared to investigate the phenol degradation mechanism and kinetic model. The degradation of phenol in TiO2/UV/H2O2 and TiO2/UV/EC system is more effective than that in TiO2/UV system. With the solution pH of 6, TiO, concentration of 0.2 g.L-1, UV illumination of 2 h, the photocatalysis removal efficiency of phenol reaches to 86%, if the current density of 12 mA.cm-2 is added, the removal efficiency of phenol could reach to 100%. The energy utilization in different catalytic systems was also compared. When phenol is degraded in 15 min, in TiO2/UV/EC system the energy utilization is the highest of 0.0306 g.(kW. h)-1 with the energy consumption of 0.0640 kW.h-1. It indicates that much more energy is used in TiO2/UV/EC system for phenol degradation. During the analysis of intermediate products in different catalysis systems, the first-order kinetic model of phenol degradation and intermediate products such as hydroquinone, catechol and benzoquinone formation were established. The kinetic model is validated the phenol degradation pathway in different catalysis systems, and also indicates the TiO2/UV/EC system could enhance phenol and intermediate products degradation.

  20. Combined transcriptomic and metabolomic approach uncovers molecular mechanisms of cold tolerance in a temperate flesh fly.

    PubMed

    Teets, Nicholas M; Peyton, Justin T; Ragland, Gregory J; Colinet, Herve; Renault, David; Hahn, Daniel A; Denlinger, David L

    2012-08-01

    The ability to respond rapidly to changes in temperature is critical for insects and other ectotherms living in variable environments. In a physiological process termed rapid cold-hardening (RCH), exposure to nonlethal low temperature allows many insects to significantly increase their cold tolerance in a matter of minutes to hours. Additionally, there are rapid changes in gene expression and cell physiology during recovery from cold injury, and we hypothesize that RCH may modulate some of these processes during recovery. In this study, we used a combination of transcriptomics and metabolomics to examine the molecular mechanisms of RCH and cold shock recovery in the flesh fly, Sarcophaga bullata. Surprisingly, out of ∼15,000 expressed sequence tags (ESTs) measured, no transcripts were upregulated during RCH, and likewise RCH had a minimal effect on the transcript signature during recovery from cold shock. However, during recovery from cold shock, we observed differential expression of ∼1,400 ESTs, including a number of heat shock proteins, cytoskeletal components, and genes from several cell signaling pathways. In the metabolome, RCH had a slight yet significant effect on several metabolic pathways, while cold shock resulted in dramatic increases in gluconeogenesis, amino acid synthesis, and cryoprotective polyol synthesis. Several biochemical pathways showed congruence at both the transcript and metabolite levels, indicating that coordinated changes in gene expression and metabolism contribute to recovery from cold shock. Thus, while RCH had very minor effects on gene expression, recovery from cold shock elicits sweeping changes in gene expression and metabolism along numerous cell signaling and biochemical pathways.

  1. Catalytic Cycle of Multicopper Oxidases Studied by Combined Quantum- and Molecular-Mechanical Free-Energy Perturbation Methods.

    PubMed

    Li, Jilai; Farrokhnia, Maryam; Rulíšek, Lubomír; Ryde, Ulf

    2015-07-01

    We have used combined quantum mechanical and molecular mechanical free-energy perturbation methods in combination with explicit solvent simulations to study the reaction mechanism of the multicopper oxidases, in particular, the regeneration of the reduced state from the native intermediate. For 52 putative states of the trinuclear copper cluster, differing in the oxidation states of the copper ions and the protonation states of water- and O2-derived ligands, we have studied redox potentials, acidity constants, isomerization reactions, as well as water- and O2 binding reactions. Thereby, we can propose a full reaction mechanism of the multicopper oxidases with atomic detail. We also show that the two copper sites in the protein communicate so that redox potentials and acidity constants of one site are affected by up to 0.2 V or 3 pKa units by a change in the oxidation state of the other site. PMID:26039490

  2. Catalytic Cycle of Multicopper Oxidases Studied by Combined Quantum- and Molecular-Mechanical Free-Energy Perturbation Methods.

    PubMed

    Li, Jilai; Farrokhnia, Maryam; Rulíšek, Lubomír; Ryde, Ulf

    2015-07-01

    We have used combined quantum mechanical and molecular mechanical free-energy perturbation methods in combination with explicit solvent simulations to study the reaction mechanism of the multicopper oxidases, in particular, the regeneration of the reduced state from the native intermediate. For 52 putative states of the trinuclear copper cluster, differing in the oxidation states of the copper ions and the protonation states of water- and O2-derived ligands, we have studied redox potentials, acidity constants, isomerization reactions, as well as water- and O2 binding reactions. Thereby, we can propose a full reaction mechanism of the multicopper oxidases with atomic detail. We also show that the two copper sites in the protein communicate so that redox potentials and acidity constants of one site are affected by up to 0.2 V or 3 pKa units by a change in the oxidation state of the other site.

  3. Effect of salmeterol/fluticasone combination on the dynamic changes of lung mechanics in mechanically ventilated COPD patients: a prospective pilot study

    PubMed Central

    Chen, Wei-Chih; Chen, Hung-Hsing; Chiang, Chi-Huei; Lee, Yu-Chin; Yang, Kuang-Yao

    2016-01-01

    Background The combined therapy of inhaled corticosteroids and long-acting beta-2 agonists for mechanically ventilated patients with COPD has never been explored. Therefore, the aim of this study was to investigate their dynamic effects on lung mechanics and gas exchange. Materials and methods Ten mechanically ventilated patients with resolution of the causes of acute exacerbations of COPD were included. Four puffs of salmeterol 25 μg/fluticasone 125 μg combination therapy were administered. Lung mechanics, including maximum resistance of the respiratory system (Rrs), end-inspiratory static compliance, peak inspiratory pressure (PIP), plateau pressure, and mean airway pressure along with gas exchange function were measured and analyzed. Results Salmeterol/fluticasone produced a significant improvement in Rrs and PIP after 30 minutes. With regard to changes in baseline values, salmeterol/fluticasone inhalation had a greater effect on PIP than Rrs. However, the therapeutic effects seemed to lose significance after 3 hours of inhaled corticosteroid/long-acting beta-2 agonist administration. Conclusion The combination of salmeterol/fluticasone-inhaled therapy in mechanically ventilated patients with COPD had a significant benefit in reducing Rrs and PIP. PMID:26869782

  4. Effects and mechanisms of the combined pollution of lanthanum and acid rain on the root phenotype of soybean seedlings.

    PubMed

    Sun, Zhaoguo; Wang, Lihong; Zhou, Qing; Huang, Xiaohua

    2013-09-01

    Rare earth pollution and acid rain pollution are both important environmental issues worldwide. In regions which simultaneously occur, the combined pollution of rare earth and acid rain becomes a new environmental issue, and the relevant research is rarely reported. Accordingly, we investigated the combined effects and mechanisms of lanthanum ion (La(3+)) and acid rain on the root phenotype of soybean seedlings. The combined pollution of low-concentration La(3+) and acid rain exerted deleterious effects on the phenotype and growth of roots, which were aggravated by the combined pollution of high-concentration La(3+) and acid rain. The deleterious effects of the combined pollution were stronger than those of single La(3+) or acid rain pollution. These stronger deleterious effects on the root phenotype and growth of roots were due to the increased disturbance of absorption and utilization of mineral nutrients in roots.

  5. Effects and mechanisms of the combined pollution of lanthanum and acid rain on the root phenotype of soybean seedlings.

    PubMed

    Sun, Zhaoguo; Wang, Lihong; Zhou, Qing; Huang, Xiaohua

    2013-09-01

    Rare earth pollution and acid rain pollution are both important environmental issues worldwide. In regions which simultaneously occur, the combined pollution of rare earth and acid rain becomes a new environmental issue, and the relevant research is rarely reported. Accordingly, we investigated the combined effects and mechanisms of lanthanum ion (La(3+)) and acid rain on the root phenotype of soybean seedlings. The combined pollution of low-concentration La(3+) and acid rain exerted deleterious effects on the phenotype and growth of roots, which were aggravated by the combined pollution of high-concentration La(3+) and acid rain. The deleterious effects of the combined pollution were stronger than those of single La(3+) or acid rain pollution. These stronger deleterious effects on the root phenotype and growth of roots were due to the increased disturbance of absorption and utilization of mineral nutrients in roots. PMID:23726884

  6. Quantum Mechanics/Molecular Mechanics Method Combined with Hybrid All-Atom and Coarse-Grained Model: Theory and Application on Redox Potential Calculations.

    PubMed

    Shen, Lin; Yang, Weitao

    2016-04-12

    We developed a new multiresolution method that spans three levels of resolution with quantum mechanical, atomistic molecular mechanical, and coarse-grained models. The resolution-adapted all-atom and coarse-grained water model, in which an all-atom structural description of the entire system is maintained during the simulations, is combined with the ab initio quantum mechanics and molecular mechanics method. We apply this model to calculate the redox potentials of the aqueous ruthenium and iron complexes by using the fractional number of electrons approach and thermodynamic integration simulations. The redox potentials are recovered in excellent accordance with the experimental data. The speed-up of the hybrid all-atom and coarse-grained water model renders it computationally more attractive. The accuracy depends on the hybrid all-atom and coarse-grained water model used in the combined quantum mechanical and molecular mechanical method. We have used another multiresolution model, in which an atomic-level layer of water molecules around redox center is solvated in supramolecular coarse-grained waters for the redox potential calculations. Compared with the experimental data, this alternative multilayer model leads to less accurate results when used with the coarse-grained polarizable MARTINI water or big multipole water model for the coarse-grained layer.

  7. Combining colloidal probe atomic force and reflection interference contrast microscopy to study the compressive mechanics of hyaluronan brushes.

    PubMed

    Attili, Seetharamaiah; Richter, Ralf P

    2012-02-14

    We describe a method that combines colloidal probe atomic force microscopy (AFM) and reflection interference contrast microscopy (RICM) to characterize the mechanical properties of thin and solvated polymer films. When analyzing polymer films, a fundamental problem in colloidal probe AFM experiments is to determine the distance at closest approach between the probe and the substrate on which the film is deposited. By combining AFM and RICM in situ, forces and absolute distances can be measured simultaneously. Using the combined setup, we quantify the compressive mechanics of films of the polysaccharide hyaluronan that is end-grafted to a supported lipid bilayer. The experimental data, and comparison with polymer theory, show that hyaluronan films are well-described as elastic, very soft and highly solvated polymer brushes. The data on these well-defined films should be a useful reference for the investigation of the more complex hyaluronan-rich coats that surround many living cells.

  8. Thrombosis of a Superior Mesenteric Vein Aneurysm: Transarterial Thrombolysis and Transhepatic Aspiration Thrombectomy

    SciTech Connect

    Hechelhammer, L.; Crook, D.W.; Widmer, U.; Wildermuth, S.; Pfammatter, T.

    2004-09-15

    We report the case of a 31-year-old woman presenting with abdominal pain due to acute thrombosis of a superior and inferior mesenteric vein aneurysm, which was treated by a combination of arterial thrombolysis and transhepatic thrombus aspiration. At the last follow-up CT, 21 months following this procedure, there was no evidence of rethrombosis, and the patient continues to do well under oral anticoagulation. The literature regarding these uncommon mesenteric vein aneurysms without portal vein involvement, as well as their treatment options, is reviewed.

  9. CH 2 Cl 2 + OH - Reaction in Aqueous Solution: A Combined Quantum Mechanical and Molecular Mechanics Study

    SciTech Connect

    Wang, Dunyou; Valiev, Marat; Garrett, Bruce C.

    2011-03-03

    The CH2Cl2 + OH- reaction in aqueous solution was investigated using combined quantum mechanical and molecular mechanics approach. We present analysis of the reactant, transition, and product state structures, and calculate the free energy reaction profile through the CCSD(T) level of the theory for the reactive region. Our results show that the aqueous environment has a significant impact on the reaction process raising the reaction barrier by ~17 kcal/mol and the reaction energy by ~20 kcal/mol. While solvation effects play a predominant role, we also find sizable contributions from solvent-induced polarization effects.

  10. Combined probabilistic and principal component analysis approach for multivariate sensitivity evaluation and application to implanted patellofemoral mechanics.

    PubMed

    Fitzpatrick, Clare K; Baldwin, Mark A; Rullkoetter, Paul J; Laz, Peter J

    2011-01-01

    Many aspects of biomechanics are variable in nature, including patient geometry, joint mechanics, implant alignment and clinical outcomes. Probabilistic methods have been applied in computational models to predict distributions of performance given uncertain or variable parameters. Sensitivity analysis is commonly used in conjunction with probabilistic methods to identify the parameters that most significantly affect the performance outcome; however, it does not consider coupled relationships for multiple output measures. Principal component analysis (PCA) has been applied to characterize common modes of variation in shape and kinematics. In this study, a novel, combined probabilistic and PCA approach was developed to characterize relationships between multiple input parameters and output measures. To demonstrate the benefits of the approach, it was applied to implanted patellofemoral (PF) mechanics to characterize relationships between femoral and patellar component alignment and loading and the resulting joint mechanics. Prior studies assessing PF sensitivity have performed individual perturbation of alignment parameters. However, the probabilistic and PCA approach enabled a more holistic evaluation of sensitivity, including identification of combinations of alignment parameters that most significantly contributed to kinematic and contact mechanics outcomes throughout the flexion cycle, and the predictive capability to estimate joint mechanics based on alignment conditions without requiring additional analysis. The approach showed comparable results for Monte Carlo sampling with 500 trials and the more efficient Latin Hypercube sampling with 50 trials. The probabilistic and PCA approach has broad applicability to biomechanical analysis and can provide insight into the interdependencies between implant design, alignment and the resulting mechanics.

  11. Combined probabilistic and principal component analysis approach for multivariate sensitivity evaluation and application to implanted patellofemoral mechanics.

    PubMed

    Fitzpatrick, Clare K; Baldwin, Mark A; Rullkoetter, Paul J; Laz, Peter J

    2011-01-01

    Many aspects of biomechanics are variable in nature, including patient geometry, joint mechanics, implant alignment and clinical outcomes. Probabilistic methods have been applied in computational models to predict distributions of performance given uncertain or variable parameters. Sensitivity analysis is commonly used in conjunction with probabilistic methods to identify the parameters that most significantly affect the performance outcome; however, it does not consider coupled relationships for multiple output measures. Principal component analysis (PCA) has been applied to characterize common modes of variation in shape and kinematics. In this study, a novel, combined probabilistic and PCA approach was developed to characterize relationships between multiple input parameters and output measures. To demonstrate the benefits of the approach, it was applied to implanted patellofemoral (PF) mechanics to characterize relationships between femoral and patellar component alignment and loading and the resulting joint mechanics. Prior studies assessing PF sensitivity have performed individual perturbation of alignment parameters. However, the probabilistic and PCA approach enabled a more holistic evaluation of sensitivity, including identification of combinations of alignment parameters that most significantly contributed to kinematic and contact mechanics outcomes throughout the flexion cycle, and the predictive capability to estimate joint mechanics based on alignment conditions without requiring additional analysis. The approach showed comparable results for Monte Carlo sampling with 500 trials and the more efficient Latin Hypercube sampling with 50 trials. The probabilistic and PCA approach has broad applicability to biomechanical analysis and can provide insight into the interdependencies between implant design, alignment and the resulting mechanics. PMID:20825941

  12. Shared and unique responses of plants to multiple individual stresses and stress combinations: physiological and molecular mechanisms

    PubMed Central

    Pandey, Prachi; Ramegowda, Venkategowda; Senthil-Kumar, Muthappa

    2015-01-01

    In field conditions, plants are often simultaneously exposed to multiple biotic and abiotic stresses resulting in substantial yield loss. Plants have evolved various physiological and molecular adaptations to protect themselves under stress combinations. Emerging evidences suggest that plant responses to a combination of stresses are unique from individual stress responses. In addition, plants exhibit shared responses which are common to individual stresses and stress combination. In this review, we provide an update on the current understanding of both unique and shared responses. Specific focus of this review is on heat–drought stress as a major abiotic stress combination and, drought–pathogen and heat–pathogen as examples of abiotic–biotic stress combinations. We also comprehend the current understanding of molecular mechanisms of cross talk in relation to shared and unique molecular responses for plant survival under stress combinations. Thus, the knowledge of shared responses of plants from individual stress studies and stress combinations can be utilized to develop varieties with broad spectrum stress tolerance. PMID:26442037

  13. Transcriptome Analysis of Sunflower Genotypes with Contrasting Oxidative Stress Tolerance Reveals Individual- and Combined- Biotic and Abiotic Stress Tolerance Mechanisms.

    PubMed

    Ramu, Vemanna S; Paramanantham, Anjugam; Ramegowda, Venkategowda; Mohan-Raju, Basavaiah; Udayakumar, Makarla; Senthil-Kumar, Muthappa

    2016-01-01

    In nature plants are often simultaneously challenged by different biotic and abiotic stresses. Although the mechanisms underlying plant responses against single stress have been studied considerably, plant tolerance mechanisms under combined stress is not understood. Also, the mechanism used to combat independently and sequentially occurring many number of biotic and abiotic stresses has also not systematically studied. From this context, in this study, we attempted to explore the shared response of sunflower plants to many independent stresses by using meta-analysis of publically available transcriptome data and transcript profiling by quantitative PCR. Further, we have also analyzed the possible role of the genes so identified in contributing to combined stress tolerance. Meta-analysis of transcriptomic data from many abiotic and biotic stresses indicated the common representation of oxidative stress responsive genes. Further, menadione-mediated oxidative stress in sunflower seedlings showed similar pattern of changes in the oxidative stress related genes. Based on this a large scale screening of 55 sunflower genotypes was performed under menadione stress and those contrasting in oxidative stress tolerance were identified. Further to confirm the role of genes identified in individual and combined stress tolerance the contrasting genotypes were individually and simultaneously challenged with few abiotic and biotic stresses. The tolerant hybrid showed reduced levels of stress damage both under combined stress and few independent stresses. Transcript profiling of the genes identified from meta-analysis in the tolerant hybrid also indicated that the selected genes were up-regulated under individual and combined stresses. Our results indicate that menadione-based screening can identify genotypes not only tolerant to multiple number of individual biotic and abiotic stresses, but also the combined stresses.

  14. Transcriptome Analysis of Sunflower Genotypes with Contrasting Oxidative Stress Tolerance Reveals Individual- and Combined- Biotic and Abiotic Stress Tolerance Mechanisms

    PubMed Central

    Ramu, Vemanna S.; Paramanantham, Anjugam; Ramegowda, Venkategowda; Mohan-Raju, Basavaiah; Udayakumar, Makarla

    2016-01-01

    In nature plants are often simultaneously challenged by different biotic and abiotic stresses. Although the mechanisms underlying plant responses against single stress have been studied considerably, plant tolerance mechanisms under combined stress is not understood. Also, the mechanism used to combat independently and sequentially occurring many number of biotic and abiotic stresses has also not systematically studied. From this context, in this study, we attempted to explore the shared response of sunflower plants to many independent stresses by using meta-analysis of publically available transcriptome data and transcript profiling by quantitative PCR. Further, we have also analyzed the possible role of the genes so identified in contributing to combined stress tolerance. Meta-analysis of transcriptomic data from many abiotic and biotic stresses indicated the common representation of oxidative stress responsive genes. Further, menadione-mediated oxidative stress in sunflower seedlings showed similar pattern of changes in the oxidative stress related genes. Based on this a large scale screening of 55 sunflower genotypes was performed under menadione stress and those contrasting in oxidative stress tolerance were identified. Further to confirm the role of genes identified in individual and combined stress tolerance the contrasting genotypes were individually and simultaneously challenged with few abiotic and biotic stresses. The tolerant hybrid showed reduced levels of stress damage both under combined stress and few independent stresses. Transcript profiling of the genes identified from meta-analysis in the tolerant hybrid also indicated that the selected genes were up-regulated under individual and combined stresses. Our results indicate that menadione-based screening can identify genotypes not only tolerant to multiple number of individual biotic and abiotic stresses, but also the combined stresses. PMID:27314499

  15. A combined methodology of multiplet and composite focal mechanism techniques for identifying seismologically active zones in Syria

    NASA Astrophysics Data System (ADS)

    Abdul-Wahed, Mohamad; Asfahani, Jamal; Al-Tahhan, Ibrahim

    2011-10-01

    This contribution is an attempt to enlarge the current knowledge about the focal mechanisms as well as the seismotectonic settings in Syria. The seismologically active zones have been identified by applying an appropriate methodology to the events recorded during the period 1995-2003 by the Syrian National Seismological Network (SNSN). The recorded events in Syria were classified as weak during the research period. It was extremely important to propose and apply an appropriate methodology to identify the focal mechanisms generating this seismic activity. The proposed methodology consists of applying a combination of two techniques: the multiplet and the composite focal mechanisms. The combination of many events in one composite focal mechanism was realized by a multiplet technique using the spectral coherence of the events as a measure of similarity. The application of the proposed methodology allows a data set of composite fault plane solutions to be obtained. Most of the composite fault plane solutions had strike-slip mechanisms which are in agreement with the configuration of seismogenic belts in Syria.

  16. Combined enzymatic and mechanical cell disruption and lipid extraction of green alga Neochloris oleoabundans.

    PubMed

    Wang, Dongqin; Li, Yanqun; Hu, Xueqiong; Su, Weimin; Zhong, Min

    2015-01-01

    Microalgal biodiesel is one of the most promising renewable fuels. The wet technique for lipids extraction has advantages over the dry method, such as energy-saving and shorter procedure. The cell disruption is a key factor in wet oil extraction to facilitate the intracellular oil release. Ultrasonication, high-pressure homogenization, enzymatic hydrolysis and the combination of enzymatic hydrolysis with high-pressure homogenization and ultrasonication were employed in this study to disrupt the cells of the microalga Neochloris oleoabundans. The cell disruption degree was investigated. The cell morphology before and after disruption was assessed with scanning and transmission electron microscopy. The energy requirements and the operation cost for wet cell disruption were also estimated. The highest disruption degree, up to 95.41%, assessed by accounting method was achieved by the combination of enzymatic hydrolysis and high-pressure homogenization. A lipid recovery of 92.6% was also obtained by the combined process. The combined process was found to be more efficient and economical compared with the individual process. PMID:25853267

  17. Optical-mechanical system for on-combine segregation of wheat by grain protein concentration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Grain segregation by grain protein concentration (GPC) may help growers maximize revenues in markets that offer protein premiums. Our objective was to develop an on-combine system for automatically segregating wheat (Triticum aestivum L.) by GPC during harvest. A multispectral optical sensor scans...

  18. Combined enzymatic and mechanical cell disruption and lipid extraction of green alga Neochloris oleoabundans.

    PubMed

    Wang, Dongqin; Li, Yanqun; Hu, Xueqiong; Su, Weimin; Zhong, Min

    2015-04-07

    Microalgal biodiesel is one of the most promising renewable fuels. The wet technique for lipids extraction has advantages over the dry method, such as energy-saving and shorter procedure. The cell disruption is a key factor in wet oil extraction to facilitate the intracellular oil release. Ultrasonication, high-pressure homogenization, enzymatic hydrolysis and the combination of enzymatic hydrolysis with high-pressure homogenization and ultrasonication were employed in this study to disrupt the cells of the microalga Neochloris oleoabundans. The cell disruption degree was investigated. The cell morphology before and after disruption was assessed with scanning and transmission electron microscopy. The energy requirements and the operation cost for wet cell disruption were also estimated. The highest disruption degree, up to 95.41%, assessed by accounting method was achieved by the combination of enzymatic hydrolysis and high-pressure homogenization. A lipid recovery of 92.6% was also obtained by the combined process. The combined process was found to be more efficient and economical compared with the individual process.

  19. Combined Enzymatic and Mechanical Cell Disruption and Lipid Extraction of Green Alga Neochloris oleoabundans

    PubMed Central

    Wang, Dongqin; Li, Yanqun; Hu, Xueqiong; Su, Weimin; Zhong, Min

    2015-01-01

    Microalgal biodiesel is one of the most promising renewable fuels. The wet technique for lipids extraction has advantages over the dry method, such as energy-saving and shorter procedure. The cell disruption is a key factor in wet oil extraction to facilitate the intracellular oil release. Ultrasonication, high-pressure homogenization, enzymatic hydrolysis and the combination of enzymatic hydrolysis with high-pressure homogenization and ultrasonication were employed in this study to disrupt the cells of the microalga Neochloris oleoabundans. The cell disruption degree was investigated. The cell morphology before and after disruption was assessed with scanning and transmission electron microscopy. The energy requirements and the operation cost for wet cell disruption were also estimated. The highest disruption degree, up to 95.41%, assessed by accounting method was achieved by the combination of enzymatic hydrolysis and high-pressure homogenization. A lipid recovery of 92.6% was also obtained by the combined process. The combined process was found to be more efficient and economical compared with the individual process. PMID:25853267

  20. Drink Refusal Training as Part of a Combined Behavioral Intervention: Effectiveness and Mechanisms of Change

    ERIC Educational Resources Information Center

    Witkiewitz, Katie; Donovan, Dennis M.; Hartzler, Bryan

    2012-01-01

    Objective: Many trials have demonstrated the effectiveness of cognitive behavioral interventions for alcohol dependence, yet few studies have examined why particular treatments are effective. This study was designed to evaluate whether drink refusal training was an effective component of a combined behavioral intervention (CBI) and whether change…

  1. Combined use of electrolytically and mechanically detachable platinum coils for endovascular treatment of cerebral aneurysms--technical note.

    PubMed

    Sugiu, Kenji; Katsumata, Atsushi; Kusaka, Noboru; Sasahara, Wataru; Tokunaga, Koji; Martin, Jean-Baptiste; Rüfenacht, Daniel A; Ohmoto, Takashi

    2004-05-01

    The combined use of Guglielmi detachable coils (GDCs) and newly developed mechanically detachable platinum coils (Detach Coil System: DCS) was evaluated for the endovascular treatment of 10 patients with cerebral aneurysms. The number and total length of detachable coils placed into the aneurysms, the detaching time for each coil, and any technical problems were recorded and evaluated. Sixty GDCs and 60 DCSs were used. The detachment time for the DCS (mean 21 seconds) was faster than that for the GDC (mean 2 minutes 35 seconds). One DCS moved inside the aneurysm during the mechanical detachment maneuver, but was successfully placed. Neither detachment system influenced the behavior of the other system during coil implantation. The DCS includes a useful J-shape coil, whereas the GDC can be detached safely in fragile aneurysms. The DCS is also cheaper. The coil systems complemented one another and the combination optimized cost and operating time.

  2. Simulation of chemical reactions in solution by a combination of classical and quantum mechanical approach

    NASA Astrophysics Data System (ADS)

    Onida, Giovanni; Andreoni, Wanda

    1995-09-01

    A classical trajectory mapping method was developed to study chemical reactions in solution and in enzymes. In this method, the trajectories were calculated on a classical potential surface and the free energy profile was obtained by mapping the classical surface to the quantum mechanical surface obtained by the semiempirical AM1 method. There is no need to perform expensive quantum mechanical calculations at each iteration step. This method was applied to proton transfer reactions both in aqueous solution and in papain. The results are encouraging, indicating the applicability of this hybrid method to chemical reactions both in solution and in enzymes.

  3. Multi-Drug Resistance Transporters and a Mechanism-Based Strategy for Assessing Risks of Pesticide Combinations to Honey Bees

    PubMed Central

    Guseman, Alex J.; Miller, Kaliah; Kunkle, Grace; Dively, Galen P.; Pettis, Jeffrey S.; Evans, Jay D.; vanEngelsdorp, Dennis; Hawthorne, David J.

    2016-01-01

    Annual losses of honey bee colonies remain high and pesticide exposure is one possible cause. Dangerous combinations of pesticides, plant-produced compounds and antibiotics added to hives may cause or contribute to losses, but it is very difficult to test the many combinations of those compounds that bees encounter. We propose a mechanism-based strategy for simplifying the assessment of combinations of compounds, focusing here on compounds that interact with xenobiotic handling ABC transporters. We evaluate the use of ivermectin as a model substrate for these transporters. Compounds that increase sensitivity of bees to ivermectin may be inhibiting key transporters. We show that several compounds commonly encountered by honey bees (fumagillin, Pristine, quercetin) significantly increased honey bee mortality due to ivermectin and significantly reduced the LC50 of ivermectin suggesting that they may interfere with transporter function. These inhibitors also significantly increased honey bees sensitivity to the neonicotinoid insecticide acetamiprid. This mechanism-based strategy may dramatically reduce the number of tests needed to assess the possibility of adverse combinations among pesticides. We also demonstrate an in vivo transporter assay that provides physical evidence of transporter inhibition by tracking the dynamics of a fluorescent substrate of these transporters (Rhodamine B) in bee tissues. Significantly more Rhodamine B remains in the head and hemolymph of bees pretreated with higher concentrations of the transporter inhibitor verapamil. Mechanism-based strategies for simplifying the assessment of adverse chemical interactions such as described here could improve our ability to identify those combinations that pose significantly greater risk to bees and perhaps improve the risk assessment protocols for honey bees and similar sensitive species. PMID:26840460

  4. Multi-Drug Resistance Transporters and a Mechanism-Based Strategy for Assessing Risks of Pesticide Combinations to Honey Bees.

    PubMed

    Guseman, Alex J; Miller, Kaliah; Kunkle, Grace; Dively, Galen P; Pettis, Jeffrey S; Evans, Jay D; vanEngelsdorp, Dennis; Hawthorne, David J

    2016-01-01

    Annual losses of honey bee colonies remain high and pesticide exposure is one possible cause. Dangerous combinations of pesticides, plant-produced compounds and antibiotics added to hives may cause or contribute to losses, but it is very difficult to test the many combinations of those compounds that bees encounter. We propose a mechanism-based strategy for simplifying the assessment of combinations of compounds, focusing here on compounds that interact with xenobiotic handling ABC transporters. We evaluate the use of ivermectin as a model substrate for these transporters. Compounds that increase sensitivity of bees to ivermectin may be inhibiting key transporters. We show that several compounds commonly encountered by honey bees (fumagillin, Pristine, quercetin) significantly increased honey bee mortality due to ivermectin and significantly reduced the LC50 of ivermectin suggesting that they may interfere with transporter function. These inhibitors also significantly increased honey bees sensitivity to the neonicotinoid insecticide acetamiprid. This mechanism-based strategy may dramatically reduce the number of tests needed to assess the possibility of adverse combinations among pesticides. We also demonstrate an in vivo transporter assay that provides physical evidence of transporter inhibition by tracking the dynamics of a fluorescent substrate of these transporters (Rhodamine B) in bee tissues. Significantly more Rhodamine B remains in the head and hemolymph of bees pretreated with higher concentrations of the transporter inhibitor verapamil. Mechanism-based strategies for simplifying the assessment of adverse chemical interactions such as described here could improve our ability to identify those combinations that pose significantly greater risk to bees and perhaps improve the risk assessment protocols for honey bees and similar sensitive species.

  5. Multi-Drug Resistance Transporters and a Mechanism-Based Strategy for Assessing Risks of Pesticide Combinations to Honey Bees.

    PubMed

    Guseman, Alex J; Miller, Kaliah; Kunkle, Grace; Dively, Galen P; Pettis, Jeffrey S; Evans, Jay D; vanEngelsdorp, Dennis; Hawthorne, David J

    2016-01-01

    Annual losses of honey bee colonies remain high and pesticide exposure is one possible cause. Dangerous combinations of pesticides, plant-produced compounds and antibiotics added to hives may cause or contribute to losses, but it is very difficult to test the many combinations of those compounds that bees encounter. We propose a mechanism-based strategy for simplifying the assessment of combinations of compounds, focusing here on compounds that interact with xenobiotic handling ABC transporters. We evaluate the use of ivermectin as a model substrate for these transporters. Compounds that increase sensitivity of bees to ivermectin may be inhibiting key transporters. We show that several compounds commonly encountered by honey bees (fumagillin, Pristine, quercetin) significantly increased honey bee mortality due to ivermectin and significantly reduced the LC50 of ivermectin suggesting that they may interfere with transporter function. These inhibitors also significantly increased honey bees sensitivity to the neonicotinoid insecticide acetamiprid. This mechanism-based strategy may dramatically reduce the number of tests needed to assess the possibility of adverse combinations among pesticides. We also demonstrate an in vivo transporter assay that provides physical evidence of transporter inhibition by tracking the dynamics of a fluorescent substrate of these transporters (Rhodamine B) in bee tissues. Significantly more Rhodamine B remains in the head and hemolymph of bees pretreated with higher concentrations of the transporter inhibitor verapamil. Mechanism-based strategies for simplifying the assessment of adverse chemical interactions such as described here could improve our ability to identify those combinations that pose significantly greater risk to bees and perhaps improve the risk assessment protocols for honey bees and similar sensitive species. PMID:26840460

  6. Cold atmospheric plasma in combination with mechanical treatment improves osteoblast growth on biofilm covered titanium discs.

    PubMed

    Duske, Kathrin; Jablonowski, Lukasz; Koban, Ina; Matthes, Rutger; Holtfreter, Birte; Sckell, Axel; Nebe, J Barbara; von Woedtke, Thomas; Weltmann, Klaus Dieter; Kocher, Thomas

    2015-06-01

    Treatment of implants with peri-implantitis is often unsuccessful, because an instrumented implant surface and residual microbial biofilm impedes re-osseointegration. The application of cold atmospheric plasma (CAP) could be a simple and effective strategy to overcome the inherent problems of peri-implantitis treatment. CAP is able to destroy and eliminate bacterial biofilms. Additionally, it increases the wettability of titanium, which supports cellular attachment. In this study, the behaviour of osteoblasts on titanium discs was analysed after treatment of bacterial biofilms with CAP, brushing, or a combination of both. A human plaque biofilm was cultured on titanium discs. Treatment with a brush (BR), 1% oxygen/argon CAP (PL), or brushing combined with CAP (BR+PL) was used to eliminate the biofilm. Discs without biofilm (C), autoclaved biofilm (AUTO) and untreated biofilm (BIO) served as controls. Subsequently, human osteoblastic cell growth (MG-63) was observed after 1 and 24 h. Biofilm remnants on BR and PL impaired osteoblastic cell development, whereas the BR+PL provided an increased area of osteoblastic cells. A five-day cell growth was only detectable on BR+PL treated discs. The combination of established brushing and CAP application may be a promising strategy to treat peri-implantitis.

  7. Glucose conjugated platinum(II) complex: antitumor superiority to oxaliplatin, combination effect and mechanism of action.

    PubMed

    Li, Hong; Gao, Xiangqian; Liu, Ran; Wang, Yu; Zhang, Menghua; Fu, Zheng; Mi, Yi; Wang, Yiqiang; Yao, Zhi; Gao, Qingzhi

    2015-08-28

    A glucose-conjugate of (trans-R,R-cyclohexane-1,2-diamine)-2-fluoromalonato-platinum(II) complex (Glu-Pt) is designed to target tumor-specific active glucose transporters (GLUTs). Despite of very high water solubility, Glu-Pt exhibits improved cytotoxicity as compared to oxaliplatin. In this study, we investigated the in vivo toxicity profiles with the maximum tolerated dose (MTD) evaluation followed by antitumor efficacy study in leukemia-bearing DBA/2 mice. Glu-Pt showed 6-fold increase in the MTD and was more efficacious against mouse L1210 ascetic leukemia than oxaliplatin at equitoxic doses. To explore the combination effect of Glu-Pt and compare with oxaliplatin-based FOLFOX chemotherapy, we investigated the two-component synergistic antitumor activity of Glu-Pt with folinic acid (FA) and 5-fluorouracil (5-FU) respectively in five human cancer cell lines followed by a comparison study with oxaliplatin in a fixed three-component in vitro FOFLOX combination. As the result, Glu-Pt exhibited superior synergistic cytotoxicity compared to oxaliplatin. Flow cytometry-based cell cycle and apoptosis study demonstrated that Glu-Pt follows the same mechanistic principles as of oxaliplatin. Glu-Pt monotherapy and its combination with FA and 5-FU may result in improved efficacy over oxaliplatin and FOLFOX regimen. The study provides fundamental data supporting the potential of Glu-Pt as a drug candidate for further (pre)clinical development.

  8. [Radical nephrectomy and thrombectomy in patients with renal cell cancer complicated by tumoral thrombosis of the renal vein and vena cava inferior].

    PubMed

    Rusyn, V I; Korsak, V V; Rusyn, A V; Boĭko, S O

    2013-01-01

    Surgical treatment was conducted in 81 patients, suffering renocellular cancer (RCC), complicated by a renal vein and vena cava inferior thrombosis. According to the Mayo clinic classification, the level of a tumoral thrombus spread was established: the 0 level--in 37 patients, the level I--in 19, the level II--in 17, the level III --in 6, and the level IV--in 2. There were substantiated the optimal surgical accesses and technique of radical nephrectomy and thrombectomy for RCC, complicated by a renal vein and vena cava inferior thrombosis. It is recommended to apply transabdominal accesses: the extended median laparotomic, bilateral subcostal of a "Chevron" or "Mercedes" type. There was shown, that the access choice depends on the level of the tumoral thrombus localization.

  9. Thrombectomy and surgical reconstruction for extensive iliocaval thrombosis in a patient with agenesis of the retrohepatic vena cava and atresia of the left renal vein.

    PubMed

    La Spada, Michele; Stilo, Francesco; Carella, Giuseppe; Salomone, Ignazio; Benedetto, Filippo; De Caridi, Giovanni; Spinelli, Francesco

    2011-08-01

    In 80% of the patients presenting with deep-venous thrombosis (DVT), a risk factor can be identified. An absent or hypoplastic infrarenal vena cava is a rare risk factor for DVT in young adults. In these cases, the prevalence of congenital anomalies of the inferior vena cava (IVC) is estimated at 0.5% of the general population, up to 5% in young people. The association with coagulopathy increases the risk of DVT. We report a case of a young man who presented with a massive caval and iliofemoral-popliteal thrombosis in presence of the agenesis of retrohepatic inferior vena cava and atresia of the left renal vein. Open thrombectomy and caval reconstruction with a polytetrafluoroethylene graft were performed. Surgical option with vein reconstruction was preferred to prevent new episodes of thrombosis and the risk of acute renal failure.

  10. Pharmacomechanical thrombectomy and catheter-directed thrombolysis of acute lower extremity deep venous thrombosis in a 9-year-old boy with inferior vena cava atresia.

    PubMed

    Hamidian Jahromi, Alireza; Coulter, Amy H; Bass, Patrick; Zhang, Wayne W; Tan, Tze-Woei

    2015-04-01

    Lower extremity deep venous thrombosis (DVT) is uncommon in the pediatric population, but it can be associated with severe symptoms and potential long-term morbidity secondary to post-thrombotic syndrome. Inferior vena cava (IVC) atresia can predispose a patient to the development of extremity DVT. There is no clear consensus on optimal management of extensive extremity DVT in pediatric patients, especially in patients with IVC anomalies. We report a case of iliofemoral DVT in a 9-year-old boy with IVC atresia and presumed protein S deficiency that was treated successfully using pharmacomechanical thrombectomy and catheter-directed thrombolysis. He was maintained on long-term anticoagulation and remained symptom free at 6 months' follow-up.

  11. Top triangle moose: Combining Higgsless and topcolor mechanisms for mass generation

    SciTech Connect

    Chivukula, R. Sekhar; Christensen, Neil D.; Coleppa, Baradhwaj; Simmons, Elizabeth H.

    2009-08-01

    We present the details of a deconstructed model that incorporates both Higgsless and top-color mechanisms. The model alleviates the tension between obtaining the correct top quark mass and keeping {delta}{rho} small that exists in many Higgsless models. It does so by singling out the top quark mass generation as arising from a Yukawa coupling to an effective top Higgs which develops a small vacuum expectation value, while electroweak symmetry breaking results largely from a Higgsless mechanism. As a result, the heavy partners of the SM fermions can be light enough to be seen at the LHC. After presenting the model, we detail the phenomenology, showing that for a broad range of masses, these heavy fermions are discoverable at the LHC.

  12. Top triangle moose: Combining Higgsless and topcolor mechanisms for mass generation

    NASA Astrophysics Data System (ADS)

    Chivukula, R. Sekhar; Christensen, Neil D.; Coleppa, Baradhwaj; Simmons, Elizabeth H.

    2009-08-01

    We present the details of a deconstructed model that incorporates both Higgsless and top-color mechanisms. The model alleviates the tension between obtaining the correct top quark mass and keeping Δρ small that exists in many Higgsless models. It does so by singling out the top quark mass generation as arising from a Yukawa coupling to an effective top Higgs which develops a small vacuum expectation value, while electroweak symmetry breaking results largely from a Higgsless mechanism. As a result, the heavy partners of the SM fermions can be light enough to be seen at the LHC. After presenting the model, we detail the phenomenology, showing that for a broad range of masses, these heavy fermions are discoverable at the LHC.

  13. Cellular graphene aerogel combines ultralow weight and high mechanical strength: A highly efficient reactor for catalytic hydrogenation

    PubMed Central

    Zhang, Bingxing; Zhang, Jianling; Sang, Xinxin; Liu, Chengcheng; Luo, Tian; Peng, Li; Han, Buxing; Tan, Xiuniang; Ma, Xue; Wang, Dong; Zhao, Ning

    2016-01-01

    The construction of three-dimensional graphene aerogels (GAs) is of great importance owing to their outstanding properties for various applications. Up to now, the combination of ultralow weight and super mechanical strength for GA remains a great challenge. Here we demonstrate the fabrication of cellular GAs by a facile, easily controlled and versatile route, i.e. the chemical reduction of graphene oxide assemblies at oil-water interface under a mild condition (70 °C). The GA is ultralight (with density <3 mg cm−3) yet mechanically resilient because the walls of the cell closely pack in a highly ordered manner to maximize mechanical strength. The GA has been utilized as an appealing reactor for catalytic hydrogenation, which exhibited great advantages such as large oil absorption capability, exceptional catalytic activity, ease of product separation and high stability. PMID:27174450

  14. Cellular graphene aerogel combines ultralow weight and high mechanical strength: A highly efficient reactor for catalytic hydrogenation.

    PubMed

    Zhang, Bingxing; Zhang, Jianling; Sang, Xinxin; Liu, Chengcheng; Luo, Tian; Peng, Li; Han, Buxing; Tan, Xiuniang; Ma, Xue; Wang, Dong; Zhao, Ning

    2016-01-01

    The construction of three-dimensional graphene aerogels (GAs) is of great importance owing to their outstanding properties for various applications. Up to now, the combination of ultralow weight and super mechanical strength for GA remains a great challenge. Here we demonstrate the fabrication of cellular GAs by a facile, easily controlled and versatile route, i.e. the chemical reduction of graphene oxide assemblies at oil-water interface under a mild condition (70 °C). The GA is ultralight (with density <3 mg cm(-3)) yet mechanically resilient because the walls of the cell closely pack in a highly ordered manner to maximize mechanical strength. The GA has been utilized as an appealing reactor for catalytic hydrogenation, which exhibited great advantages such as large oil absorption capability, exceptional catalytic activity, ease of product separation and high stability. PMID:27174450

  15. Cellular graphene aerogel combines ultralow weight and high mechanical strength: A highly efficient reactor for catalytic hydrogenation.

    PubMed

    Zhang, Bingxing; Zhang, Jianling; Sang, Xinxin; Liu, Chengcheng; Luo, Tian; Peng, Li; Han, Buxing; Tan, Xiuniang; Ma, Xue; Wang, Dong; Zhao, Ning

    2016-05-12

    The construction of three-dimensional graphene aerogels (GAs) is of great importance owing to their outstanding properties for various applications. Up to now, the combination of ultralow weight and super mechanical strength for GA remains a great challenge. Here we demonstrate the fabrication of cellular GAs by a facile, easily controlled and versatile route, i.e. the chemical reduction of graphene oxide assemblies at oil-water interface under a mild condition (70 °C). The GA is ultralight (with density <3 mg cm(-3)) yet mechanically resilient because the walls of the cell closely pack in a highly ordered manner to maximize mechanical strength. The GA has been utilized as an appealing reactor for catalytic hydrogenation, which exhibited great advantages such as large oil absorption capability, exceptional catalytic activity, ease of product separation and high stability.

  16. Cellular graphene aerogel combines ultralow weight and high mechanical strength: A highly efficient reactor for catalytic hydrogenation

    NASA Astrophysics Data System (ADS)

    Zhang, Bingxing; Zhang, Jianling; Sang, Xinxin; Liu, Chengcheng; Luo, Tian; Peng, Li; Han, Buxing; Tan, Xiuniang; Ma, Xue; Wang, Dong; Zhao, Ning

    2016-05-01

    The construction of three-dimensional graphene aerogels (GAs) is of great importance owing to their outstanding properties for various applications. Up to now, the combination of ultralow weight and super mechanical strength for GA remains a great challenge. Here we demonstrate the fabrication of cellular GAs by a facile, easily controlled and versatile route, i.e. the chemical reduction of graphene oxide assemblies at oil-water interface under a mild condition (70 °C). The GA is ultralight (with density <3 mg cm‑3) yet mechanically resilient because the walls of the cell closely pack in a highly ordered manner to maximize mechanical strength. The GA has been utilized as an appealing reactor for catalytic hydrogenation, which exhibited great advantages such as large oil absorption capability, exceptional catalytic activity, ease of product separation and high stability.

  17. Controller design for flexible, distributed parameter mechanical arms via combined state space and frequency domain techniques

    NASA Technical Reports Server (NTRS)

    Book, W. J.; Majett, M.

    1982-01-01

    The potential benefits of the ability to control more flexible mechanical arms are discussed. A justification is made in terms of speed of movement. A new controller design procedure is then developed to provide this capability. It uses both a frequency domain representation and a state variable representation of the arm model. The frequency domain model is used to update the modal state variable model to insure decoupled states. The technique is applied to a simple example with encouraging results.

  18. How Changes in Extracellular Matrix Mechanics and Gene Expression Variability Might Combine to Drive Cancer Progression

    PubMed Central

    Bischof, Ashley G.; Mannix, Robert J.; Tobin, Heather; Bar-Yam, Yaneer; Bellin, Robert M.; Ingber, Donald E.

    2013-01-01

    Changes in extracellular matrix (ECM) structure or mechanics can actively drive cancer progression; however, the underlying mechanism remains unknown. Here we explore whether this process could be mediated by changes in cell shape that lead to increases in genetic noise, given that both factors have been independently shown to alter gene expression and induce cell fate switching. We do this using a computer simulation model that explores the impact of physical changes in the tissue microenvironment under conditions in which physical deformation of cells increases gene expression variability among genetically identical cells. The model reveals that cancerous tissue growth can be driven by physical changes in the microenvironment: when increases in cell shape variability due to growth-dependent increases in cell packing density enhance gene expression variation, heterogeneous autonomous growth and further structural disorganization can result, thereby driving cancer progression via positive feedback. The model parameters that led to this prediction are consistent with experimental measurements of mammary tissues that spontaneously undergo cancer progression in transgenic C3(1)-SV40Tag female mice, which exhibit enhanced stiffness of mammary ducts, as well as progressive increases in variability of cell-cell relations and associated cell shape changes. These results demonstrate the potential for physical changes in the tissue microenvironment (e.g., altered ECM mechanics) to induce a cancerous phenotype or accelerate cancer progression in a clonal population through local changes in cell geometry and increased phenotypic variability, even in the absence of gene mutation. PMID:24098430

  19. Combined quantum mechanics (TDDFT) and classical electrodynamics (Mie theory) methods for calculating surface enhanced Raman and hyper-Raman spectra.

    PubMed

    Mullin, Jonathan; Valley, Nicholas; Blaber, Martin G; Schatz, George C

    2012-09-27

    Multiscale models that combine quantum mechanics and classical electrodynamics are presented, which allow for the evaluation of surface-enhanced Raman (SERS) and hyper-Raman scattering spectra (SEHRS) for both chemical (CHEM) and electrodynamic (EM) enhancement mechanisms. In these models, time-dependent density functional theory (TDDFT) for a system consisting of the adsorbed molecule and a metal cluster fragment of the metal particle is coupled to Mie theory for the metal particle, with the surface of the cluster being overlaid with the surface of the metal particle. In model A, the electromagnetic enhancement from plasmon-excitation of the metal particle is combined with the chemical enhancement associated with a static treatment of the molecule-metal structure to determine overall spectra. In model B, the frequency dependence of the Raman spectrum of the isolated molecule is combined with the enhancements determined in model A to refine the enhancement estimate. An equivalent theory at the level of model A is developed for hyper-Raman spectra calculations. Application to pyridine interacting with a 20 nm diameter silver sphere is presented, including comparisons with an earlier model (denoted G), which combines plasmon enhanced fields with gas-phase Raman (or hyper-Raman) spectra. The EM enhancement factor for spherical particles at 357 nm is found to be 10(4) and 10(6) for SERS and SEHRS, respectively. Including both chemical and electromagnetic mechanisms at the level of model A leads to enhancements on the order of 10(4) and 10(9) for SERS and SEHRS.

  20. Rapid diffusion of magic-size islands by combined glide and vacancy mechanisms

    SciTech Connect

    Perez, D; Voter, A F; Uche, O U; Hamilton, J C

    2009-01-01

    Using molecular dynamics, nudged elastic band, and embedded atom methods, we show that certain 2D Ag islands undergo extremely rapid one-dimensional diffusion on Cu(001) surfaces. Indeed, below 300K, hopping rates for 'magic-size' islands are orders of magnitude faster than hopping rates for single Ag adatoms. This rapid diffusion requires both the c(10 x 2) hexagonally-packed superstructure typical of Ag on Cu(001) and appropriate 'magic-sizes' for the islands. The novel highly-cooperative diffusion mechanism presented here couples vacancy diffusion with simultaneous core glide.

  1. A combined experimental-numerical approach for determining mechanical properties of aluminum subjects to nanoindentation

    PubMed Central

    Liu, Mao; Lu, Cheng; Tieu, Kiet Anh; Peng, Ching-Tun; Kong, Charlie

    2015-01-01

    A crystal plasticity finite element method (CPFEM) model has been developed to investigate the mechanical properties and micro-texture evolution of single-crystal aluminum induced by a sharp Berkovich indenter. The load-displacement curves, pile-up patterns and lattice rotation angles from simulation are consistent with the experimental results. The pile-up phenomenon and lattice rotation have been discussed based on the theory of crystal plasticity. In addition, a polycrystal tensile CPFEM model has been established to explore the relationship between indentation hardness and yield stress. The elastic constraint factor C is slightly larger than conventional value 3 due to the strain hardening. PMID:26464128

  2. Investigation of the mechanical properties of a low-shrinkage liquid crystalline matrix combined with nano-hydroxyapatite.

    PubMed

    Liu, Wen Wen; He, Xiao Ping; Mo, An Chun; Yao, Qian Qian; Ye, Jun; Jing, Nie

    2011-01-01

    The objective of this study was to investigate the mechanical properties of a low-shrinkage acrylate liquid crystalline resin matrix (ALCRM), (4-3-(acryloyloxy)-2-hydroxypropoxy) phenyl 4-(3-(acryloyloxy)-2-hydroxypropoxy) benzoate, combined with nano-hydroxyapatite (na-HA). The ALCRM monomer and diluent monomer triethylene glycol dimethacrylate (TEGDMA) were mixed at a mass ratio of 7:3 to prepare the resin matrix. The volume shrinkage of the ALCRM/TEGDMA and the traditional resin matrix Bis-GMA (2, 2-bis [4-(3-methacryloxy-2-hydroxypropoxy) phenyl] propane)/TEGDMA were measured. Then 20%, 30%, and 40% na-HA were added to ALCRM/TEGDMA and Bis-GMA/TEGDMA, respectively. Compressive strength (CS) and Vickers hardness (VHN) were tested to identify mechanical properties of the composites. The volume shrinkage of the ALCRM/TEGDMA was 3.60% ± 0.36%, which was lower than that of the traditional resin matrix. Moreover, with the same amount of na-HA filler, the mechanical properties of the ALCRM-based composites were superior to those of Bis-GMA-based composites. ALCRM-based composites exhibited the highest CS and VHN values when the filler content was 30%. These results indicate that the low-shrinkage liquid crystalline resin matrix has strong mechanical properties after incorporating the na-HA. The experimental ALCRM-based composites have promising potential for the development of novel low-shrinkage dental resins with strong mechanical properties. PMID:21980241

  3. Investigation of the mechanical properties of a low-shrinkage liquid crystalline matrix combined with nano-hydroxyapatite.

    PubMed

    Liu, Wen Wen; He, Xiao Ping; Mo, An Chun; Yao, Qian Qian; Ye, Jun; Jing, Nie

    2011-01-01

    The objective of this study was to investigate the mechanical properties of a low-shrinkage acrylate liquid crystalline resin matrix (ALCRM), (4-3-(acryloyloxy)-2-hydroxypropoxy) phenyl 4-(3-(acryloyloxy)-2-hydroxypropoxy) benzoate, combined with nano-hydroxyapatite (na-HA). The ALCRM monomer and diluent monomer triethylene glycol dimethacrylate (TEGDMA) were mixed at a mass ratio of 7:3 to prepare the resin matrix. The volume shrinkage of the ALCRM/TEGDMA and the traditional resin matrix Bis-GMA (2, 2-bis [4-(3-methacryloxy-2-hydroxypropoxy) phenyl] propane)/TEGDMA were measured. Then 20%, 30%, and 40% na-HA were added to ALCRM/TEGDMA and Bis-GMA/TEGDMA, respectively. Compressive strength (CS) and Vickers hardness (VHN) were tested to identify mechanical properties of the composites. The volume shrinkage of the ALCRM/TEGDMA was 3.60% ± 0.36%, which was lower than that of the traditional resin matrix. Moreover, with the same amount of na-HA filler, the mechanical properties of the ALCRM-based composites were superior to those of Bis-GMA-based composites. ALCRM-based composites exhibited the highest CS and VHN values when the filler content was 30%. These results indicate that the low-shrinkage liquid crystalline resin matrix has strong mechanical properties after incorporating the na-HA. The experimental ALCRM-based composites have promising potential for the development of novel low-shrinkage dental resins with strong mechanical properties.

  4. The use of combined cathodoluminescence and EBSD analysis: a case study investigating grain boundary migration mechanisms in quartz.

    PubMed

    Piazolo, S; Prior, D J; Holness, M D

    2005-02-01

    Grain boundary migration is an important mechanism of microstructural modification both in rocks and in metals. Combining detailed cathodoluminescence (CL) and electron backscatter diffraction (EBSD) analysis offers the opportunity to relate directly changes in crystallographic orientation to migrating boundaries. We observe the following features in naturally heated quartz grains from the thermal aureole of the Ballachulish Igneous Complex (Scotland, U.K.): (a) propagation of substructures and twin boundaries in swept areas both parallel and at an angle to the growth direction, (b) development of slightly different crystallographic orientations and new twin boundaries at both the growth interfaces and within the swept area and (c) a gradual change in crystallographic orientation in the direction of growth. All these features are compatible with a growth mechanism in which single atoms are attached and detached both at random and at preferential sites, i.e. crystallographically controlled sites or kinks in boundary ledges. Additionally, strain fields caused by defects and/or trace element incorporation may facilitate nucleation sites for new crystallographic orientations at distinct growth interfaces but also at continuously migrating boundaries. This study illustrates the usefulness of combined CL and EBSD in microprocess analysis. Further work in this direction may provide detailed insight into both the mechanism of static grain growth and the energies and mobilities of boundaries in terms of misorientation and grain boundary plane orientation.

  5. The use of combined cathodoluminescence and EBSD analysis: a case study investigating grain boundary migration mechanisms in quartz.

    PubMed

    Piazolo, S; Prior, D J; Holness, M D

    2005-02-01

    Grain boundary migration is an important mechanism of microstructural modification both in rocks and in metals. Combining detailed cathodoluminescence (CL) and electron backscatter diffraction (EBSD) analysis offers the opportunity to relate directly changes in crystallographic orientation to migrating boundaries. We observe the following features in naturally heated quartz grains from the thermal aureole of the Ballachulish Igneous Complex (Scotland, U.K.): (a) propagation of substructures and twin boundaries in swept areas both parallel and at an angle to the growth direction, (b) development of slightly different crystallographic orientations and new twin boundaries at both the growth interfaces and within the swept area and (c) a gradual change in crystallographic orientation in the direction of growth. All these features are compatible with a growth mechanism in which single atoms are attached and detached both at random and at preferential sites, i.e. crystallographically controlled sites or kinks in boundary ledges. Additionally, strain fields caused by defects and/or trace element incorporation may facilitate nucleation sites for new crystallographic orientations at distinct growth interfaces but also at continuously migrating boundaries. This study illustrates the usefulness of combined CL and EBSD in microprocess analysis. Further work in this direction may provide detailed insight into both the mechanism of static grain growth and the energies and mobilities of boundaries in terms of misorientation and grain boundary plane orientation. PMID:15683412

  6. Designing power system simulators for the smart grid: combining controls, communications, and electro-mechanical dynamics

    SciTech Connect

    Nutaro, James J

    2011-01-01

    Open source software has a leading role in research on simulation technology for electrical power systems. Research simulators demonstrate new features for which there is nascent but growing demand not yet provided for by commercial simulators. Of particular interest is the inclusion of models of software-intensive and communication-intensive controls in simulations of power system transients. This paper describes two features of the ORNL power system simulator that help it meet this need. First is its use of discrete event simulation for all aspects of the model: control, communication, and electro-mechanical dynamics. Second is an interoperability interface that enables the ORNL power system simulator to be integrated with existing, discrete event simulators of digital communication systems. The paper concludes with a brief discussion of how these aspects of the ORNL power system simulator might be inserted into production-grade simulation tools.

  7. Central pain mechanisms following combined acid and capsaicin perfusion of the human oesophagus.

    PubMed

    Brock, Christina; Andresen, Trine; Frøkjaer, Jens Brøndum; Gale, Jeremy; Olesen, Anne Estrup; Arendt-Nielsen, Lars; Drewes, Asbjørn Mohr

    2010-03-01

    Visceral afferents originating from different gut-segments converge at the spinal level. We hypothesized that chemically-induced hyperalgesia in the oesophagus could provoke widespread visceral hypersensitivity and also influence descending modulatory pain pathways. Fifteen healthy volunteers were studied at baseline, 30, 60 and 90 min after randomized perfusion of the distal oesophagus with either saline or 180 ml 0.1M HCl+2mg capsaicin. Electro-stimulation of the oesophagus, 8 cm proximal to the perfusion site, rectosigmoid electrical stimulation and rectal mechanical and heat stimulations were used. Evoked brain potentials were recorded after electrical stimulations before and after oesophageal perfusion. After the perfusion, rectal hyperalgesia to heat (P<0.01, 37%) and mechanical (P=0.01, 11%) stimulations were demonstrated. In contrast, hypoalgesia to electro-stimulation was observed in both the oesophagus (P<0.03, 23%) and the sigmoid colon (P<0.001, 18%). Referred pain areas to electro-stimulation in oesophagus were reduced by 13% after perfusion (P=0.01). Evoked brain potentials to rectosigmoid stimulations showed decreased latencies and amplitudes of P1, N1 and P2 (P<0.05), whereas oesophagus-evoked brain potentials were unaffected after perfusion. In conclusion, modality-specific hyperalgesia was demonstrated in the lower gut following chemical sensitization of the oesophagus, reflecting widespread central hyperexcitability. Conversely, hypoalgesia to electrical stimulation, decreases in referred pain and latencies of evoked brain potentials was seen. This outcome may reflect a counterbalancing activation of descending inhibitory pathways. As these findings are also seen in the clinical setting, the model may be usable for future basic and pharmacological studies.

  8. Decoding the mechanisms of gait generation in salamanders by combining neurobiology, modeling and robotics.

    PubMed

    Bicanski, Andrej; Ryczko, Dimitri; Knuesel, Jérémie; Harischandra, Nalin; Charrier, Vanessa; Ekeberg, Örjan; Cabelguen, Jean-Marie; Ijspeert, Auke Jan

    2013-10-01

    Vertebrate animals exhibit impressive locomotor skills. These locomotor skills are due to the complex interactions between the environment, the musculo-skeletal system and the central nervous system, in particular the spinal locomotor circuits. We are interested in decoding these interactions in the salamander, a key animal from an evolutionary point of view. It exhibits both swimming and stepping gaits and is faced with the problem of producing efficient propulsive forces using the same musculo-skeletal system in two environments with significant physical differences in density, viscosity and gravitational load. Yet its nervous system remains comparatively simple. Our approach is based on a combination of neurophysiological experiments, numerical modeling at different levels of abstraction, and robotic validation using an amphibious salamander-like robot. This article reviews the current state of our knowledge on salamander locomotion control, and presents how our approach has allowed us to obtain a first conceptual model of the salamander spinal locomotor networks. The model suggests that the salamander locomotor circuit can be seen as a lamprey-like circuit controlling axial movements of the trunk and tail, extended by specialized oscillatory centers controlling limb movements. The interplay between the two types of circuits determines the mode of locomotion under the influence of sensory feedback and descending drive, with stepping gaits at low drive, and swimming at high drive.

  9. Combination of Mechanical and Molecular Filtration for Enhanced Enrichment of Circulating Tumor Cells.

    PubMed

    Meunier, Anne; Hernández-Castro, Javier Alejandro; Turner, Kate; Li, Kebin; Veres, Teodor; Juncker, David

    2016-09-01

    Circulating tumor cells (CTCs) have been linked to cancer progression but are difficult to isolate, as they are very rare and heterogeneous, covering a range of sizes and expressing different molecular receptors. Filtration has emerged as a simple and powerful method to enrich CTCs but only captures cells above a certain size regardless of molecular characteristics. Here, we introduce antibody-functionalized microfilters to isolate CTCs based on both size and surface receptor expression. We present a 3D printed filtration cartridge with microfabricated polymer filters with 8, 10, 12, 15, or 20 μm-diameter pores. Pristine filters were used to optimize sample dilution, rinsing protocol, flow rate, and pore size, leading to >80% for the recovery of spiked cancer cells with very low white blood cell contamination (<1000). Then, filters were functionalized with antibodies against either epithelial cell adhesion molecule (EpCAM) or epidermal growth factor receptor (EGFR) and the cartridges were used to enrich breast (MDA-MB-231, MCF-7) and renal (786-O, A-498) cancer cells expressing various levels of EpCAM and EGFR. Cancer cells were spiked into human blood, and when using filters with antibodies specific to a molecular receptor expressed on a cell, efficiency was increased to >96%. These results suggest that filtration can be optimized to target specific CTC characteristics such as size and receptor expression and that a diverse range of CTCs may be captured using particular combinations of pore size, filtration parameters, and antibody functionalization. PMID:27442305

  10. Combining 3D printed forms with textile structures - mechanical and geometrical properties of multi-material systems

    NASA Astrophysics Data System (ADS)

    Sabantina, L.; Kinzel, F.; Ehrmann, A.; Finsterbusch, K.

    2015-07-01

    The 3D printing belongs to the rapidly emerging technologies which have the chance to revolutionize the way products are created. In the textile industry, several designers have already presented creations of shoes, dresses or other garments which could not be produced with common techniques. 3D printing, however, is still far away from being a usual process in textile and clothing production. The main challenge results from the insufficient mechanical properties, especially the low tensile strength, of pure 3D printed products, prohibiting them from replacing common technologies such as weaving or knitting. Thus, one way to the application of 3D printed forms in garments is combining them with textile fabrics, the latter ensuring the necessary tensile strength. This article reports about different approaches to combine 3D printed polymers with different textile materials and fabrics, showing chances and limits of this technique.

  11. Research on the mechanical properties of a glass fiber reinforced polymer-steel combined truss structure.

    PubMed

    Liu, Pengfei; Zhao, Qilin; Li, Fei; Liu, Jinchun; Chen, Haosen

    2014-01-01

    An assembled plane truss structure used for vehicle loading is designed and manufactured. In the truss, the glass fiber reinforced polymer (GFRP) tube and the steel joint are connected by a new technology featuring a pretightened tooth connection. The detailed description for the rod and node design is introduced in this paper, and a typical truss panel is fabricated. Under natural conditions, the short-term load test and long-term mechanical performance test for one year are performed to analyze its performance and conduct a comparative analysis for a reasonable FEM model. The study shows that the design and fabrication for the node of an assembled truss panel are convenient, safe, and reliable; because of the creep control design of the rods, not only does the short-term structural stiffness meet the design requirement but also the long-term creep deformation tends towards stability. In addition, no significant change is found in the elastic modules, so this structure can be applied in actual engineering. Although the safety factor for the strength of the composite rods is very large, it has a lightweight advantage over the steel truss for the low density of GFRP. In the FEM model, simplifying the node as a hinge connection relatively conforms to the actual status. PMID:25247203

  12. Research on the Mechanical Properties of a Glass Fiber Reinforced Polymer-Steel Combined Truss Structure

    PubMed Central

    Liu, Pengfei; Zhao, Qilin; Li, Fei; Liu, Jinchun; Chen, Haosen

    2014-01-01

    An assembled plane truss structure used for vehicle loading is designed and manufactured. In the truss, the glass fiber reinforced polymer (GFRP) tube and the steel joint are connected by a new technology featuring a pretightened tooth connection. The detailed description for the rod and node design is introduced in this paper, and a typical truss panel is fabricated. Under natural conditions, the short-term load test and long-term mechanical performance test for one year are performed to analyze its performance and conduct a comparative analysis for a reasonable FEM model. The study shows that the design and fabrication for the node of an assembled truss panel are convenient, safe, and reliable; because of the creep control design of the rods, not only does the short-term structural stiffness meet the design requirement but also the long-term creep deformation tends towards stability. In addition, no significant change is found in the elastic modules, so this structure can be applied in actual engineering. Although the safety factor for the strength of the composite rods is very large, it has a lightweight advantage over the steel truss for the low density of GFRP. In the FEM model, simplifying the node as a hinge connection relatively conforms to the actual status. PMID:25247203

  13. Metabolic and target-site mechanisms combine to confer strong DDT resistance in Anopheles gambiae.

    PubMed

    Mitchell, Sara N; Rigden, Daniel J; Dowd, Andrew J; Lu, Fang; Wilding, Craig S; Weetman, David; Dadzie, Samuel; Jenkins, Adam M; Regna, Kimberly; Boko, Pelagie; Djogbenou, Luc; Muskavitch, Marc A T; Ranson, Hilary; Paine, Mark J I; Mayans, Olga; Donnelly, Martin J

    2014-01-01

    The development of resistance to insecticides has become a classic exemplar of evolution occurring within human time scales. In this study we demonstrate how resistance to DDT in the major African malaria vector Anopheles gambiae is a result of both target-site resistance mechanisms that have introgressed between incipient species (the M- and S-molecular forms) and allelic variants in a DDT-detoxifying enzyme. Sequencing of the detoxification enzyme, Gste2, from DDT resistant and susceptible strains of An. gambiae, revealed a non-synonymous polymorphism (I114T), proximal to the DDT binding domain, which segregated with strain phenotype. Recombinant protein expression and DDT metabolism analysis revealed that the proteins from the susceptible strain lost activity at higher DDT concentrations, characteristic of substrate inhibition. The effect of I114T on GSTE2 protein structure was explored through X-ray crystallography. The amino acid exchange in the DDT-resistant strain introduced a hydroxyl group nearby the hydrophobic DDT-binding region. The exchange does not result in structural alterations but is predicted to facilitate local dynamics and enzyme activity. Expression of both wild-type and 114T alleles the allele in Drosophila conferred an increase in DDT tolerance. The 114T mutation was significantly associated with DDT resistance in wild caught M-form populations and acts in concert with target-site mutations in the voltage gated sodium channel (Vgsc-1575Y and Vgsc-1014F) to confer extreme levels of DDT resistance in wild caught An. gambiae.

  14. Molecular mechanisms of cocaine reward: Combined dopamine and serotonin transporter knockouts eliminate cocaine place preference

    PubMed Central

    Sora, Ichiro; Hall, F. Scott; Andrews, Anne M.; Itokawa, Masanari; Li, Xiao-Fei; Wei, Hong-Bing; Wichems, Christine; Lesch, Klaus-Peter; Murphy, Dennis L.; Uhl, George R.

    2001-01-01

    Cocaine blocks uptake by neuronal plasma membrane transporters for dopamine (DAT), serotonin (SERT), and norepinephrine (NET). Cocaine reward/reinforcement has been linked to actions at DAT or to blockade of SERT. However, knockouts of neither DAT, SERT, or NET reduce cocaine reward/reinforcement, leaving substantial uncertainty about cocaine's molecular mechanisms for reward. Conceivably, the molecular bases of cocaine reward might display sufficient redundancy that either DAT or SERT might be able to mediate cocaine reward in the other's absence. To test this hypothesis, we examined double knockout mice with deletions of one or both copies of both the DAT and SERT genes. These mice display viability, weight gain, histologic features, neurochemical parameters, and baseline behavioral features that allow tests of cocaine influences. Mice with even a single wild-type DAT gene copy and no SERT copies retain cocaine reward/reinforcement, as measured by conditioned place-preference testing. However, mice with no DAT and either no or one SERT gene copy display no preference for places where they have previously received cocaine. The serotonin dependence of cocaine reward in DAT knockout mice is thus confirmed by the elimination of cocaine place preference in DAT/SERT double knockout mice. These results provide insights into the brain molecular targets necessary for cocaine reward in knockout mice that develop in their absence and suggest novel strategies for anticocaine medication development. PMID:11320258

  15. Research on the mechanical properties of a glass fiber reinforced polymer-steel combined truss structure.

    PubMed

    Liu, Pengfei; Zhao, Qilin; Li, Fei; Liu, Jinchun; Chen, Haosen

    2014-01-01

    An assembled plane truss structure used for vehicle loading is designed and manufactured. In the truss, the glass fiber reinforced polymer (GFRP) tube and the steel joint are connected by a new technology featuring a pretightened tooth connection. The detailed description for the rod and node design is introduced in this paper, and a typical truss panel is fabricated. Under natural conditions, the short-term load test and long-term mechanical performance test for one year are performed to analyze its performance and conduct a comparative analysis for a reasonable FEM model. The study shows that the design and fabrication for the node of an assembled truss panel are convenient, safe, and reliable; because of the creep control design of the rods, not only does the short-term structural stiffness meet the design requirement but also the long-term creep deformation tends towards stability. In addition, no significant change is found in the elastic modules, so this structure can be applied in actual engineering. Although the safety factor for the strength of the composite rods is very large, it has a lightweight advantage over the steel truss for the low density of GFRP. In the FEM model, simplifying the node as a hinge connection relatively conforms to the actual status.

  16. Mechanism of Reversible Peptide-Bilayer Attachment: Combined Simulation and Experimental Single-Molecule Study.

    PubMed

    Schwierz, Nadine; Krysiak, Stefanie; Hugel, Thorsten; Zacharias, Martin

    2016-01-26

    The binding of peptides and proteins to lipid membrane surfaces is of fundamental importance for many membrane-mediated cellular processes. Using closely matched molecular dynamics simulations and atomic force microscopy experiments, we study the force-induced desorption of single peptide chains from phospholipid bilayers to gain microscopic insight into the mechanism of reversible attachment. This approach allows quantification of desorption forces and decomposition of peptide-membrane interactions into energetic and entropic contributions. In both simulations and experiments, the desorption forces of peptides with charged and polar side chains are much smaller than those for hydrophobic peptides. The adsorption of charged/polar peptides to the membrane surface is disfavored by the energetic components, requires breaking of hydrogen bonds involving the peptides, and is favored only slightly by entropy. By contrast, the stronger adsorption of hydrophobic peptides is favored both by energy and by entropy and the desorption forces increase with increasing side-chain hydrophobicity. Interestingly, the calculated net adsorption free energies per residue correlate with experimental results of single residues, indicating that side-chain free energy contributions are largely additive. This observation can help in the design of peptides with tailored adsorption properties and in the estimation of membrane binding properties of peripheral membrane proteins. PMID:26717083

  17. Antibiotic prescription patterns in the empiric therapy of severe sepsis: combination of antimicrobials with different mechanisms of action reduces mortality

    PubMed Central

    2012-01-01

    Introduction Although early institution of adequate antimicrobial therapy is lifesaving in sepsis patients, optimal antimicrobial strategy has not been established. Moreover, the benefit of combination therapy over monotherapy remains to be determined. Our aims are to describe patterns of empiric antimicrobial therapy in severe sepsis, assessing the impact of combination therapy, including antimicrobials with different mechanisms of action, on mortality. Methods This is a Spanish national multicenter study, analyzing all patients admitted to ICUs who received antibiotics within the first 6 hours of diagnosis of severe sepsis or septic shock. Antibiotic-prescription patterns in community-acquired infections and nosocomial infections were analyzed separately and compared. We compared the impact on mortality of empiric antibiotic treatment, including antibiotics with different mechanisms of action, termed different-class combination therapy (DCCT), with that of monotherapy and any other combination therapy possibilities (non-DCCT). Results We included 1,372 patients, 1,022 (74.5%) of whom had community-acquired sepsis and 350 (25.5%) of whom had nosocomial sepsis. The most frequently prescribed antibiotic agents were β-lactams (902, 65.7%) and carbapenems (345, 25.1%). DCCT was administered to 388 patients (28.3%), whereas non-DCCT was administered to 984 (71.7%). The mortality rate was significantly lower in patients administered DCCTs than in those who were administered non-DCCTs (34% versus 40%; P = 0.042). The variables independently associated with mortality were age, male sex, APACHE II score, and community origin of the infection. DCCT was a protective factor against in-hospital mortality (odds ratio (OR), 0.699; 95% confidence interval (CI), 0.522 to 0.936; P = 0.016), as was urologic focus of infection (OR, 0.241; 95% CI, 0.102 to 0.569; P = 0.001). Conclusions β-Lactams, including carbapenems, are the most frequently prescribed antibiotics in empiric

  18. A tunneling field-effect transistor exploiting internally combined band-to-band and barrier tunneling mechanisms

    NASA Astrophysics Data System (ADS)

    Lattanzio, Livio; Biswas, Arnab; De Michielis, Luca; Ionescu, Adrian M.

    2011-03-01

    This letter proposes a hybrid abrupt switch principle and a corresponding device architecture that combines quantum mechanical band-to-band and barrier tunneling mechanisms. The device overcomes the intrinsically low on-current (ION) of conventional tunnel field-effect transistors (TFETs) and the 60 mV/dec subthreshold swing limitation of metal-oxide-semiconductor FETs at room temperature. The device principle and characteristics are studied through two-dimensional numerical simulations. The predicted performance of such hybrid TFET architecture, implementing an ultrathin (0.5 nm) tunneling dielectric between metal source and silicon channel are: average SS values as low as 43 mV/dec, ION˜49.3 μA/μm, and ION/IOFF˜107.

  19. Dynamics of associating polymers and the sticky Rouse model: a study by combined dielectric and dynamic mechanical techniques

    NASA Astrophysics Data System (ADS)

    Wang, Yangyang; Cosby, Tyler; Sangoro, Joshua

    Reversible association through non-covalent bonding is ubiquitous in the soft matter world. Despite decades of studies, the dynamics of associating polymers have not been well understood. Here we examine the dynamics of butadiene- and isoprene-based model polymeric systems with pairwise association through hydrogen bonding. Compared to ionomers, where reversible crosslinks are typically not well defined, these hydrogen bonding polymers are associated through strictly binary contacts and thus provide a better opportunity to test theoretical ideas. By combining dielectric spectroscopy and dynamic mechanical measurement, we are able to identify both chain and junction dynamics and analyze their motional coupling mechanism. The results are discussed in the context of the sticky Rouse model.

  20. Enhanced correlation between quantitative ultrasound and structural and mechanical properties of bone using combined transmission-reflection measurement

    PubMed Central

    Lin, Liangjun; Lin, Wei; Qin, Yi-Xian

    2015-01-01

    Quantitative ultrasound (QUS) is capable of predicting the principal structural orientation of trabecular bone; this orientation is highly correlated with the mechanical strength of trabecular bone. Irregular shape of bone, however, would increase variation in such a prediction, especially under human in vivo measurement. This study was designed to combine transmission and reflection modes of QUS measurement to improve the prediction for the structural and mechanical properties of trabecular bone. QUS, mechanical testing, and micro computed tomography (μCT) scanning were performed on 24 trabecular bone cubes harvested from a bovine distal femur to obtain the mechanical and structural parameters. Transmission and reflection modes of QUS measurement in the transverse and frontal planes were performed in a confined 60° angle range with 5° increment. The QUS parameters, attenuation (ATT) and velocity (UV), obtained from transmission mode, were normalized to the specimen thickness acquired from reflection mode. Analysis of covariance showed that the combined transmission-reflection modes improved prediction for the structural and Young's modulus of bone in comparison to the traditional QUS measurement performed only in the medial-lateral orientation. In the transverse plane, significant improvement between QUS and μCT was found in ATT vs bone surface density (BS/BV) (p < 0.05), ATT vs trabecular thickness (Tb.Th) (p < 0.01), ATT vs degree of anisotropy (DA) (p < 0.05), UV vs trabecular bone number (Tb.N) (p < 0.05), and UV vs Tb.Th (p < 0.001). In the frontal plane, significant improvement was found in ATT vs structural model index (SMI) (p < 0.01), ATT vs bone volume fraction (BV/TV) (p < 0.01), ATT vs BS/BV (p < 0.001), ATT vs Tb.Th (p < 0.001), ATT vs DA (p < 0.001), and ATT vs modulus (p < 0.001), UV vs SMI (p < 0.01), UV vs BV/TV (p < 0.05), UV vs BS/BV (p < 0.05), UV vs Tb.Th (p < 0.01), UV vs

  1. Combined solid-state and mechanically-switched transformer tap-changer

    SciTech Connect

    Eitzmann, M.A.; Hill, A.T.

    1995-04-18

    Disclosed is an End-Turn Solid-State Switching (ETSS) transformer tap which makes use of a high-speed solid-state switching network to select either the end-turn lead or one of a number of non-isolated taps on a transformer regulating winding, and connects the selected tap to, while disconnecting the previously selected tap from, a single output conductor carrying the transformer load current. ETSS effectively changes the reference to one of the possible taps interfaced to a solid-state switching network. The same transformer regulating winding connected to ETSS can also be connected in series with a slow-speed mechanically-switched tap-changer (LTC). ETSS selects one connection point on the regulating winding while LTC operation selects the second point. A difference voltage is produced, depending on the number of turns between the ETSS selected tap and the LTC selected tap. The sign of the difference in voltage depends on whether the ETSS selected tap is higher or lower than the LTC selected tap. The difference or tap selected voltage is in series with the transformer load current. In one embodiment, the high-speed solid-state switching network uses a ``Staggered Progression of Solid-State Switches`` (SPSS) to select one of a number of non-isolated taps on a transformer regulating winding and connect the selected tap in series with the load circuit. A switching network arranged according to the method SPSS reduces the necessary total switch power rating, and steady-state losses. ETSS can accomplish modulation of the tap-selected voltage about the nominal value established by the LTC. 9 figs.

  2. Combining experimental and simulation studies to constrain the mechanism of metasomatic vein formation

    NASA Astrophysics Data System (ADS)

    Pilet, Sebastien; Ulmer, Peter; Baker, Michael B.; Stolper, Edward M.; Muntener, Othmar

    2010-05-01

    composition (hawaiite) [5] indicates that for all hydrous liquids, the different phases formed upon differentiation are similar even though the proportions of hydrous versus anhydrous minerals could vary significantly. This suggests that the formation of amphibole-bearing metasomatic veins observed in the lithospheric mantle could be linked to the differentiation of initial hydrous liquids ranging from ne-normative to hy-normative in composition. (2) To evaluate the trace element composition of amphibole-cumulates, we did Monte Carlo simulations of metasomatic vein formation in the context of mid-ocean ridges based on the model proposed by Niu and O'Hara [2]. This model assumes that some liquid produced at depth at the periphery of a ridge is not collected to form MORB, but generates a modal and cryptic metasomatic enrichment of the lithospheric mantle. For the calculation, we assume that initial metasomatic agents represent low-degree melts from peridotitic sources similar to depleted MORB mantle. The inferred polybaric crystallization sequence of the low-degree melts was constrained by experiments and the mineral compositions and modes observed in metasomatic veins. The main conclusion of these simulations is that the compositions of calculated hydrous cumulates are highly enriched in incompatible trace elements and that their patterns share many similarities with the patterns of alkaline OIBs (positive Nb/La, negative Ce/Pb, same slope of REE). The combination of fractional crystallisation experiments and Monte Carlo simulations supports the model proposed by Harte et al. [5] for the formation of metasomatic veins; and suggests that low degree melts from 'normal' mantle following by fractional crystallisation at high pressure allowed to produce hydrous cumulates suitable to be a source of alkaline magma observed in intraplate setting. [1] Lloyd and Bailey (1975) Phys. Chem. of the Earth, 9: 389-416; [2] Niu and O'Hara (2003) J. Geophys. Res. 108, 2209; [3] Pilet et al

  3. Mechanical competence of ovariectomy-induced compromised bone after single or combined treatment with high-frequency loading and bisphosphonates

    PubMed Central

    Camargos G. V.; Bhattacharya P.; van Lenthe G. H.; Del Bel Cury A. A.; Naert I.; Duyck J.; Vandamme K.

    2015-01-01

    Osteoporosis leads to increased bone fragility, thus effective approaches enhancing bone strength are needed. Hence, this study investigated the effect of single or combined application of high-frequency (HF) loading through whole body vibration (WBV) and alendronate (ALN) on the mechanical competence of ovariectomy-induced osteoporotic bone. Thirty-four female Wistar rats were ovariectomized (OVX) or sham-operated (shOVX) and divided into five groups: shOVX, OVX-shWBV, OVX-WBV, ALN-shWBV and ALN-WBV. (Sham)WBV loading was applied for 10 min/day (130 to 150 Hz at 0.3g) for 14 days and ALN at 2 mg/kg/dose was administered 3x/week. Finite element analysis based on micro-CT was employed to assess bone biomechanical properties, relative to bone micro-structural parameters. HF loading application to OVX resulted in an enlarged cortex, but it was not able to improve the biomechanical properties. ALN prevented trabecular bone deterioration and increased bone stiffness and bone strength of OVX bone. Finally, the combination of ALN with HF resulted in an increased cortical thickness in OVX rats when compared to single treatments. Compared to HF loading, ALN treatment is preferred for improving the compromised mechanical competence of OVX bone. In addition, the association of ALN with HF loading results in an additive effect on the cortical thickness. PMID:26027958

  4. Effects of provinol and its combinations with clinically used antiasthmatics on airway defense mechanisms in experimental allergic asthma.

    PubMed

    Kazimierová, I; Jošková, M; Pecháňová, O; Šutovská, M; Fraňová, S

    2015-01-01

    Our previous studies show that provinol, a polyphenolic compound, has anti-inflammatory activity during allergic inflammation. In the present study we investigated the effects of provinol and its combinations with clinically used antiasthmatics: budesonide or theophylline on airway defense mechanisms during experimental allergic asthma. Separate groups of guinea pigs were treated during the course of 21-day ovalbumin sensitization with provinol (20 mg/kg/day, p.o.), or budesonide (1 mM by inhalation), or theophylline (10 mg/kg/day, i.p.), and with a half-dose combination of provinol+budesonide or provinol+theophylline. Airways defense mechanisms: cough reflex and specific airway resistance (sRaw) were evaluated in vivo. Tracheal smooth muscle reactivity and mucociliary clearance were examined in vitro. The findings were that provinol caused significant decreases in sRaw and in tracheal smooth muscle contractility, a suppression of cough reflex, and positively modulated ciliary beat frequency. The bronchodilatory and antitussive effects of provinol were comparable with those of budesonide and theophylline. Provinol given as add-on treatment significantly potentiated the effects of budesonide or theophylline, although the doses of each were halved. We conclude that provinol not only has bronchodilatory and antitussive effects, but also potentiates similar effects exerted by budesonide and theophylline.

  5. The molecular mechanism of action of aspirin, curcumin and sulforaphane combinations in the chemoprevention of pancreatic cancer

    PubMed Central

    THAKKAR, ARVIND; SUTARIA, DHRUVITKUMAR; GRANDHI, B. KARTHIK; WANG, JEFFREY; PRABHU, SUNIL

    2013-01-01

    Pancreatic cancer ranks as the fourth most deadly form of cancer in the United States with ~37,000 deaths each year. The present study evaluated the chemopreventive potential of a combination of aspirin (ASP), curcumin (CUR) and sulforaphane (SFN) in low doses to human pancreatic cancer cells, MIA PaCa-2 and Panc-1. Results demonstrated that low doses of ASP (1 mM), CUR (10 μM) and SFN (5 μM) (ACS) combination reduced cell viability by ~70% (P<0.001), and also induced cell apoptosis by ~51% (P<0.001) accompanied by activation of caspase-3 and Poly(ADP-ribose) polymerase (PARP) proteins. The NF-κB DNA binding activity was inhibited by ~45% (P<0.01) and ~75% (P<0.001) in MIA PaCa-2 and Panc-1 cells, respectively. Mechanistic studies revealed that ACS promoted increase expression of phospho extracellular signal-regulated kinase 1/2 (P-ERK1/2), c-Jun, p38 MAPK and p53 proteins. Furthermore, the cells pretreated with U0126 (ERK1/2 inhibitor) partially abolished the effect of ACS on cell viability. Data from this study demonstrate that a low-dose ACS combination inhibits cell growth by inducing cell apoptosis, and proposes sustained activation of the ERK1/2 signaling pathway as one of the possible mechanisms. PMID:23404329

  6. A bifurcation study to guide the design of a landing gear with a combined uplock/downlock mechanism

    PubMed Central

    Knowles, James A. C.; Lowenberg, Mark H.; Neild, Simon A.; Krauskopf, Bernd

    2014-01-01

    This paper discusses the insights that a bifurcation analysis can provide when designing mechanisms. A model, in the form of a set of coupled steady-state equations, can be derived to describe the mechanism. Solutions to this model can be traced through the mechanism's state versus parameter space via numerical continuation, under the simultaneous variation of one or more parameters. With this approach, crucial features in the response surface, such as bifurcation points, can be identified. By numerically continuing these points in the appropriate parameter space, the resulting bifurcation diagram can be used to guide parameter selection and optimization. In this paper, we demonstrate the potential of this technique by considering an aircraft nose landing gear, with a novel locking strategy that uses a combined uplock/downlock mechanism. The landing gear is locked when in the retracted or deployed states. Transitions between these locked states and the unlocked state (where the landing gear is a mechanism) are shown to depend upon the positions of two fold point bifurcations. By performing a two-parameter continuation, the critical points are traced to identify operational boundaries. Following the variation of the fold points through parameter space, a minimum spring stiffness is identified that enables the landing gear to be locked in the retracted state. The bifurcation analysis also shows that the unlocking of a retracted landing gear should use an unlock force measure, rather than a position indicator, to de-couple the effects of the retraction and locking actuators. Overall, the study demonstrates that bifurcation analysis can enhance the understanding of the influence of design choices over a wide operating range where nonlinearity is significant. PMID:25484601

  7. A bifurcation study to guide the design of a landing gear with a combined uplock/downlock mechanism.

    PubMed

    Knowles, James A C; Lowenberg, Mark H; Neild, Simon A; Krauskopf, Bernd

    2014-12-01

    This paper discusses the insights that a bifurcation analysis can provide when designing mechanisms. A model, in the form of a set of coupled steady-state equations, can be derived to describe the mechanism. Solutions to this model can be traced through the mechanism's state versus parameter space via numerical continuation, under the simultaneous variation of one or more parameters. With this approach, crucial features in the response surface, such as bifurcation points, can be identified. By numerically continuing these points in the appropriate parameter space, the resulting bifurcation diagram can be used to guide parameter selection and optimization. In this paper, we demonstrate the potential of this technique by considering an aircraft nose landing gear, with a novel locking strategy that uses a combined uplock/downlock mechanism. The landing gear is locked when in the retracted or deployed states. Transitions between these locked states and the unlocked state (where the landing gear is a mechanism) are shown to depend upon the positions of two fold point bifurcations. By performing a two-parameter continuation, the critical points are traced to identify operational boundaries. Following the variation of the fold points through parameter space, a minimum spring stiffness is identified that enables the landing gear to be locked in the retracted state. The bifurcation analysis also shows that the unlocking of a retracted landing gear should use an unlock force measure, rather than a position indicator, to de-couple the effects of the retraction and locking actuators. Overall, the study demonstrates that bifurcation analysis can enhance the understanding of the influence of design choices over a wide operating range where nonlinearity is significant. PMID:25484601

  8. Physiological mechanisms contributing to the QTL-combination effects on improved performance of IR64 rice NILs under drought

    PubMed Central

    Henry, Amelia; Swamy, B. P. Mallikarjuna; Dixit, Shalabh; Torres, Rolando D.; Batoto, Tristram C.; Manalili, Mervin; Anantha, M. S.; Mandal, N. P.; Kumar, Arvind

    2015-01-01

    Characterizing the physiological mechanisms behind major-effect drought-yield quantitative trait loci (QTLs) can provide an understanding of the function of the QTLs—as well as plant responses to drought in general. In this study, we characterized rice (Oryza sativa L.) genotypes with QTLs derived from drought-tolerant traditional variety AdaySel that were introgressed into drought-susceptible high-yielding variety IR64, one of the most popular megavarieties in South Asian rainfed lowland systems. Of the different combinations of the four QTLs evaluated, genotypes with two QTLs (qDTY 2.2 + qDTY 4.1) showed the greatest degree of improvement under drought compared with IR64 in terms of yield, canopy temperature, and normalized difference vegetation index (NDVI). Furthermore, qDTY 2.2 and qDTY 4.1 showed a potential for complementarity in that they were each most effective under different severities of drought stress. Multiple drought-response mechanisms were observed to be conferred in the genotypes with the two-QTL combination: higher root hydraulic conductivity and in some cases greater root growth at depth. As evidenced by multiple leaf water status and plant growth indicators, these traits affected transpiration but not transpiration efficiency or harvest index. The results from this study highlight the complex interactions among major-effect drought-yield QTLs and the drought-response traits they confer, and the need to evaluate the optimal combinations of QTLs that complement each other when present in a common genetic background. PMID:25680791

  9. Usefulness of local delivery of thrombolytics before thrombectomy in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention (the delivery of thrombolytics before thrombectomy in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention [DISSOLUTION] randomized trial).

    PubMed

    Greco, Cesare; Pelliccia, Francesco; Tanzilli, Gaetano; Tinti, Maria Denitza; Salenzi, Paola; Cicerchia, Cristina; Schiariti, Michele; Franzoni, Ferdinando; Speziale, Giuseppe; Gallo, Pietro; Gaudio, Carlo

    2013-09-01

    Thrombus aspiration during percutaneous coronary intervention can result in improved rates of normal epicardial flow and myocardial perfusion, but several unmet needs remain. The purpose of the Delivery of thrombolytIcs before thrombectomy in patientS with ST-segment elevatiOn myocardiaL infarction Undergoing primary percuTaneous coronary interventION (DISSOLUTION) trial was to evaluate the hypothesis that local delivery of thrombolytics can enhance the efficacy of thrombus aspiration in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention. A total of 102 patients with ST-segment elevation myocardial infarction and angiographic evidence of massive thrombosis in the culprit artery were randomly assigned to receive a local, intrathrombus bolus of 200,000 U of urokinase (n = 51) or saline solution (n = 51) by way of an infusion microcatheter, followed by manual aspiration thrombectomy. The end points included the final Thrombolysis In Myocardial Infarction flow grade and frame count, myocardial blush grade, 60-minute ST-segment resolution >70%, and major adverse cardiac and cerebrovascular events, defined as the death, reinfarction, stroke, or clinically driven target vessel revascularization at 6 months. The use of intrathrombus urokinase was associated with a significantly higher incidence of Thrombolysis In Myocardial Infarction flow grade 3 (90% vs 66%, p = 0.008) and lower postpercutaneous coronary intervention Thrombolysis In Myocardial Infarction frame count (19 ± 15 vs 25 ± 17, p = 0.033). The postprocedural myocardial perfusion was significantly increased with the use of urokinase (myocardial blush grade 2 or 3, 68% vs 45%, p = 0.028), with more patients showing ST-segment resolution >70% (82% vs 55%, p = 0.006). At 6 months of follow-up, the patients treated with intrathrombus urokinase showed a better major adverse cardiac event-free survival (6% vs 21%; log-rank p = 0.044). In conclusion, local

  10. Traits, properties, and performance: how woody plants combine hydraulic and mechanical functions in a cell, tissue, or whole plant.

    PubMed

    Lachenbruch, Barbara; McCulloh, Katherine A

    2014-12-01

    This review presents a framework for evaluating how cells, tissues, organs, and whole plants perform both hydraulic and mechanical functions. The morphological alterations that affect dual functionality are varied: individual cells can have altered morphology; tissues can have altered partitioning to functions or altered cell alignment; and organs and whole plants can differ in their allocation to different tissues, or in the geometric distribution of the tissues they have. A hierarchical model emphasizes that morphological traits influence the hydraulic or mechanical properties; the properties, combined with the plant unit's environment, then influence the performance of that plant unit. As a special case, we discuss the mechanisms by which the proxy property wood density has strong correlations to performance but without direct causality. Traits and properties influence multiple aspects of performance, and there can be mutual compensations such that similar performance occurs. This compensation emphasizes that natural selection acts on, and a plant's viability is determined by, its performance, rather than its contributing traits and properties. Continued research on the relationships among traits, and on their effects on multiple aspects of performance, will help us better predict, manage, and select plant material for success under multiple stresses in the future.

  11. Estimation of coefficient of friction for a mechanical system with combined rolling-sliding contact using vibration measurements

    NASA Astrophysics Data System (ADS)

    Sundar, Sriram; Dreyer, Jason T.; Singh, Rajendra

    2015-06-01

    A new dynamic experiment is proposed to estimate the coefficient of friction for a mechanical system with a combined rolling-sliding contact under a mixed lubrication regime. The experiment is designed and instrumented based on an analogous contact mechanics model, taking into consideration the constraints to ensure no impact and no sliding velocity reversal. The system consists of a cam (rotating with a constant speed) having a point contact with a follower that oscillates about a frictionless pivot, while maintaining contact with the cam with the help of a well-designed translational spring. The viscous damping elements for contact are identified for two different lubricants from an impulse test using the half-power bandwidth method. Dynamic responses (with the cam providing an input to the system) are measured in terms of the follower acceleration and the reaction forces at the follower pivot. A frequency domain based signal processing technique is proposed to estimate the coefficient of friction using the complex-valued Fourier amplitudes of the measured forces and acceleration. The coefficient of friction is estimated for the mechanical system with different surface roughnesses using two lubricants; these are also compared with similar values for both dry and lubricated cases as reported in the literature. An empirical relationship for the coefficient of friction is suggested based on a prior model under a mixed lubrication regime. Possible sources of errors in the estimation procedure are identified and quantified.

  12. Identifying protein aggregation mechanisms and quantifying aggregation rates from combined monomer depletion and continuous scattering.

    PubMed

    Barnett, Gregory V; Drenski, Michael; Razinkov, Vladimir; Reed, Wayne F; Roberts, Christopher J

    2016-10-15

    Parallel temperature initial rates (PTIR) from chromatographic separation of aggregating protein solutions are combined with continuous simultaneous multiple sample light scattering (SMSLS) to make quantitative deductions about protein aggregation kinetics and mechanisms. PTIR determines the rates at which initially monomeric proteins are converted to aggregates over a range of temperatures, under initial-rate conditions. Using SMSLS for the same set of conditions provides time courses of the absolute Rayleigh scattering ratio, IR(t), from which a potentially different measure of aggregation rates can be quantified. The present report compares these measures of aggregation rates across a range of solution conditions that result in different aggregation mechanisms for anti-streptavidin (AS) immunoglobulin gamma-1 (IgG1). The results illustrate how the two methods provide complementary information when deducing aggregation mechanisms, as well as cases where they provide new mechanistic details that were not possible to deduce in previous work. Criteria are presented for when the two techniques are expected to give equivalent results for quantitative rates, the potential limitations when solution non-idealities are large, as well as a comparison of the temperature dependence of AS-IgG1 aggregation rates with published data for other antibodies. PMID:27510552

  13. Responses to combined abiotic and biotic stress in tomato are governed by stress intensity and resistance mechanism

    PubMed Central

    Kissoudis, Christos; Sunarti, Sri; van de Wiel, Clemens; Visser, Richard G.F.; van der Linden, C. Gerard; Bai, Yuling

    2016-01-01

    Stress conditions in agricultural ecosystems can occur at variable intensities. Different resistance mechanisms against abiotic stress and pathogens are deployed by plants. Thus, it is important to examine plant responses to stress combinations under different scenarios. Here, we evaluated the effect of different levels of salt stress ranging from mild to severe (50, 100, and 150mM NaCl) on powdery mildew resistance and overall performance of tomato introgression lines with contrasting levels of partial resistance, as well as near-isogenic lines (NILs) carrying the resistance gene Ol-1 (associated with a slow hypersensitivity response; HR), ol-2 (an mlo mutant associated with papilla formation), and Ol-4 (an R gene associated with a fast HR). Powdery mildew resistance was affected by salt stress in a genotype- and stress intensity-dependent manner. In susceptible and partial resistant lines, increased susceptibility was observed under mild salt stress (50mM) which was accompanied by accelerated cell death-like senescence. In contrast, severe salt stress (150mM) reduced disease symptoms. Na+ and Cl− accumulation in the leaves was linearly related to the decreased pathogen symptoms under severe stress. In contrast, complete resistance mediated by ol-2 and Ol-4 was unaffected under all treatment combinations, and was associated with a decreased growth penalty. Increased susceptibility and senescence under combined stress in NIL-Ol-1 was associated with the induction of ethylene and jasmonic acid pathway genes and the cell wall invertase gene LIN6. These results highlight the significance of stress severity and resistance type on the plant’s performance under the combination of abiotic and biotic stress. PMID:27436279

  14. Responses to combined abiotic and biotic stress in tomato are governed by stress intensity and resistance mechanism.

    PubMed

    Kissoudis, Christos; Sunarti, Sri; van de Wiel, Clemens; Visser, Richard G F; van der Linden, C Gerard; Bai, Yuling

    2016-09-01

    Stress conditions in agricultural ecosystems can occur at variable intensities. Different resistance mechanisms against abiotic stress and pathogens are deployed by plants. Thus, it is important to examine plant responses to stress combinations under different scenarios. Here, we evaluated the effect of different levels of salt stress ranging from mild to severe (50, 100, and 150mM NaCl) on powdery mildew resistance and overall performance of tomato introgression lines with contrasting levels of partial resistance, as well as near-isogenic lines (NILs) carrying the resistance gene Ol-1 (associated with a slow hypersensitivity response; HR), ol-2 (an mlo mutant associated with papilla formation), and Ol-4 (an R gene associated with a fast HR). Powdery mildew resistance was affected by salt stress in a genotype- and stress intensity-dependent manner. In susceptible and partial resistant lines, increased susceptibility was observed under mild salt stress (50mM) which was accompanied by accelerated cell death-like senescence. In contrast, severe salt stress (150mM) reduced disease symptoms. Na(+) and Cl(-) accumulation in the leaves was linearly related to the decreased pathogen symptoms under severe stress. In contrast, complete resistance mediated by ol-2 and Ol-4 was unaffected under all treatment combinations, and was associated with a decreased growth penalty. Increased susceptibility and senescence under combined stress in NIL-Ol-1 was associated with the induction of ethylene and jasmonic acid pathway genes and the cell wall invertase gene LIN6. These results highlight the significance of stress severity and resistance type on the plant's performance under the combination of abiotic and biotic stress.

  15. Developmentally Inspired Combined Mechanical and Biochemical Signaling Approach on Zonal Lineage Commitment of Mesenchymal Stem Cells in Articular Cartilage Regeneration

    PubMed Central

    Karimi, Tahereh; Barati, Danial; Karaman, Ozan; Moeinzadeh, Sina; Jabbari, Esmaiel

    2014-01-01

    Articular cartilage is organized into multiple zones including superficial, middle and calcified zones with distinct cellular and extracellular components to impart lubrication, compressive strength, and rigidity for load transmission to bone, respectively. During native cartilage tissue development, changes in biochemical, mechanical, and cellular factors direct the formation of stratified structure of articular cartilage. The objective of this work was to investigate the effect of combined gradients in cell density, matrix stiffness, and zone-specific growth factors on the zonal organization of articular cartilage. Human mesenchymal stem cells (hMSCs) were encapsulated in acrylate-functionalized lactide-chain-extended polyethylene glycol (SPELA) gels simulating cell density and stiffness of the superficial, middle and calcified zones. The cell-encapsulated gels were cultivated in medium supplemented with growth factors specific to each zone and the expression of zone-specific markers was measured with incubation time. Encapsulation of 60×106 cells/mL hMSCs in a soft gel (80 kPa modulus) and cultivation with a combination of TGF-β1 (3 ng/mL) and BMP-7 (100 ng/mL) led to the expression of markers for the superficial zone. Conversely, encapsulation of 15×106 cells/mL hMSCs in a stiff gel (320 MPa modulus) and cultivation with a combination of TGF-β1 (30 ng/mL) and hydroxyapatite (3%) led to the expression of markers for the calcified zone. Further, encapsulation of 20×106 cells/mL hMSCs in a gel with 2.1 MPa modulus and cultivation with a combination of TGF-β1 (30 ng/mL) and IGF-1 (100 ng/mL) led to up-regulation of the middle zone markers. Results demonstrate that a developmental approach with gradients in cell density, matrix stiffness, and zone-specific growth factors can potentially regenerate zonal structure of the articular cartilage. PMID:25387395

  16. Responses to combined abiotic and biotic stress in tomato are governed by stress intensity and resistance mechanism.

    PubMed

    Kissoudis, Christos; Sunarti, Sri; van de Wiel, Clemens; Visser, Richard G F; van der Linden, C Gerard; Bai, Yuling

    2016-09-01

    Stress conditions in agricultural ecosystems can occur at variable intensities. Different resistance mechanisms against abiotic stress and pathogens are deployed by plants. Thus, it is important to examine plant responses to stress combinations under different scenarios. Here, we evaluated the effect of different levels of salt stress ranging from mild to severe (50, 100, and 150mM NaCl) on powdery mildew resistance and overall performance of tomato introgression lines with contrasting levels of partial resistance, as well as near-isogenic lines (NILs) carrying the resistance gene Ol-1 (associated with a slow hypersensitivity response; HR), ol-2 (an mlo mutant associated with papilla formation), and Ol-4 (an R gene associated with a fast HR). Powdery mildew resistance was affected by salt stress in a genotype- and stress intensity-dependent manner. In susceptible and partial resistant lines, increased susceptibility was observed under mild salt stress (50mM) which was accompanied by accelerated cell death-like senescence. In contrast, severe salt stress (150mM) reduced disease symptoms. Na(+) and Cl(-) accumulation in the leaves was linearly related to the decreased pathogen symptoms under severe stress. In contrast, complete resistance mediated by ol-2 and Ol-4 was unaffected under all treatment combinations, and was associated with a decreased growth penalty. Increased susceptibility and senescence under combined stress in NIL-Ol-1 was associated with the induction of ethylene and jasmonic acid pathway genes and the cell wall invertase gene LIN6. These results highlight the significance of stress severity and resistance type on the plant's performance under the combination of abiotic and biotic stress. PMID:27436279

  17. Combined quantum mechanics/molecular mechanics (QM/MM) simulations for protein-ligand complexes: free energies of binding of water molecules in influenza neuraminidase.

    PubMed

    Woods, Christopher J; Shaw, Katherine E; Mulholland, Adrian J

    2015-01-22

    The applicability of combined quantum mechanics/molecular mechanics (QM/MM) methods for the calculation of absolute binding free energies of conserved water molecules in protein/ligand complexes is demonstrated. Here, we apply QM/MM Monte Carlo simulations to investigate binding of water molecules to influenza neuraminidase. We investigate five different complexes, including those with the drugs oseltamivir and peramivir. We investigate water molecules in two different environments, one more hydrophobic and one hydrophilic. We calculate the free-energy change for perturbation of a QM to MM representation of the bound water molecule. The calculations are performed at the BLYP/aVDZ (QM) and TIP4P (MM) levels of theory, which we have previously demonstrated to be consistent with one another for QM/MM modeling. The results show that the QM to MM perturbation is significant in both environments (greater than 1 kcal mol(-1)) and larger in the more hydrophilic site. Comparison with the same perturbation in bulk water shows that this makes a contribution to binding. The results quantify how electronic polarization differences in different environments affect binding affinity and also demonstrate that extensive, converged QM/MM free-energy simulations, with good levels of QM theory, are now practical for protein/ligand complexes.

  18. Theoretical Characterization of the Spectral Density of the Water-Soluble Chlorophyll-Binding Protein from Combined Quantum Mechanics/Molecular Mechanics Molecular Dynamics Simulations.

    PubMed

    Rosnik, Andreana M; Curutchet, Carles

    2015-12-01

    Over the past decade, both experimentalists and theorists have worked to develop methods to describe pigment-protein coupling in photosynthetic light-harvesting complexes in order to understand the molecular basis of quantum coherence effects observed in photosynthesis. Here we present an improved strategy based on the combination of quantum mechanics/molecular mechanics (QM/MM) molecular dynamics (MD) simulations and excited-state calculations to predict the spectral density of electronic-vibrational coupling. We study the water-soluble chlorophyll-binding protein (WSCP) reconstituted with Chl a or Chl b pigments as the system of interest and compare our work with data obtained by Pieper and co-workers from differential fluorescence line-narrowing spectra (Pieper et al. J. Phys. Chem. B 2011, 115 (14), 4042-4052). Our results demonstrate that the use of QM/MM MD simulations where the nuclear positions are still propagated at the classical level leads to a striking improvement of the predicted spectral densities in the middle- and high-frequency regions, where they nearly reach quantitative accuracy. This demonstrates that the so-called "geometry mismatch" problem related to the use of low-quality structures in QM calculations, not the quantum features of pigments high-frequency motions, causes the failure of previous studies relying on similar protocols. Thus, this work paves the way toward quantitative predictions of pigment-protein coupling and the comprehension of quantum coherence effects in photosynthesis.

  19. Molecular mechanisms for inhibition of colon cancer cells by combined epigenetic-modulating epigallocatechin gallate and sodium butyrate

    SciTech Connect

    Saldanha, Sabita N.; Kala, Rishabh; Tollefsbol, Trygve O.

    2014-05-15

    Bioactive compounds are considered safe and have been shown to alter genetic and epigenetic profiles of tumor cells. However, many of these changes have been reported at molecular concentrations higher than physiologically achievable levels. We investigated the role of the combinatorial effects of epigallocatechin gallate (EGCG), a predominant polyphenol in green tea, and sodium butyrate (NaB), a dietary microbial fermentation product of fiber, in the regulation of survivin, which is an overexpressed anti-apoptotic protein in colon cancer cells. For the first time, our study showed that the combination treatment induced apoptosis and cell cycle arrest in RKO, HCT-116 and HT-29 colorectal cancer cells. This was found to be regulated by the decrease in HDAC1, DNMT1, survivin and HDAC activity in all three cell lines. A G2/M arrest was observed for RKO and HCT-116 cells, and G1 arrest for HT-29 colorectal cancer cells for combinatorial treatment. Further experimentation of the molecular mechanisms in RKO colorectal cancer (CRC) cells revealed a p53-dependent induction of p21 and an increase in nuclear factor kappa B (NF-κB)-p65. An increase in double strand breaks as determined by gamma-H2A histone family member X (γ-H2AX) protein levels and induction of histone H3 hyperacetylation was also observed with the combination treatment. Further, we observed a decrease in global CpG methylation. Taken together, these findings suggest that at low and physiologically achievable concentrations, combinatorial EGCG and NaB are effective in promoting apoptosis, inducing cell cycle arrest and DNA-damage in CRC cells. - Highlights: • EGCG and NaB as a combination inhibits colorectal cancer cell proliferation. • The combination treatment induces DNA damage, G2/M and G1 arrest and apoptosis. • Survivin is effectively down-regulated by the combination treatment. • p21 and p53 expressions are induced by the combination treatment. • Epigenetic proteins DNMT1 and HDAC1 are

  20. Rescue Thrombectomy in Large Vessel Occlusion Strokes Leads to Better Outcomes than Intravenous Thrombolysis Alone: A ‘Real World’ Applicability of the Recent Trials

    PubMed Central

    Nogueira, Raul G.; Zaidat, Osama O.; Castonguay, Alicia C.; Haussen, Diogo C.; Martin, Coleman O.; Holloway, William E.; Mueller-Kronast, Nils; English, Joey; Linfante, Italo; Dabus, Guilherme; Malisch, Tim W.; Marden, Franklin A.; Bozorgchami, Hormozd; Xavier, Andrew; Rai, Ansaar T.; Froehler, Michael T.; Badruddin, Aamir; Nguyen, Thanh N.; Taqi, M. Asif; Abraham, Michael G.; Janardhan, Vallabh; Yoo, Albert J.; Shaltoni, Hashem; Abou-Chebl, Alex; Chen, Peng R.; Britz, Gavin W.; Novakovic, Roberta; Nanda, Ashish; Kaushal, Ritesh; Issa, Mohammad A.; Frankel, Michael R.; Gupta, Rishi

    2016-01-01

    Background The Interventional Management of Stroke III (IMS-III) trial demonstrated no benefit for intravenous recombinant tissue plasminogen activator (IV rt-PA) followed by endovascular therapy versus IV rt-PA alone. However, IMS-III mostly included earlier generation devices. The recent thrombectomy trials have incorporated the stent-retriever technology, but their generalizability remains unknown. Methods The North American Solitaire Acute Stroke (NASA) registry recruited patients treated with the Solitaire FR™ device between March 2012 and February 2013. The NASA-IMS-III-Like Group (NILG baseline NIHSS score ≥10 who received IV rt-PA) was compared to the IV rt-PA and IV + intra-arterial (IA)-IMS-III groups and the MR CLEAN, ESCAPE, SWIFT Prime, and REVASCAT trial controls to assess the stent-retriever treatment in the ‘real-world’ setting. The NILG was also compared to non-IV rt-PA NASA patients to evaluate the impact of IV rt-PA on thrombectomy. Results A total of 136 of the 354 NASA patients fulfilled criteria for the NILG. Baseline characteristics were well balanced across groups. Time from onset to puncture was higher in NILG than IV+IA-IMS-III patients (274 ± 112 vs. 208 ± 47 min, p < 0.0001). Occlusions involving the intracranial ICA, MCA-M1, or basilar arteries were more common in NILG than IV+IA-IMS-III patients (91.2 vs. 47.2%, p < 0.00001). Modified thrombolysis in cerebral infarction ≥2b reperfusion was higher in NILG than IV+IA-IMS-III patients (74.3 vs. 39.6%, p < 0.00001). A 90-day modified Rankin Scale score ≤2 was more frequent in the NILG than IV+IA-IMS-III patients (51.9 vs. 40.8%, p = 0.03) and MR CLEAN (51.9 vs. 19.1%, p < 0.00001), ESCAPE (51.9 vs. 29.3%, p = 0.0002), SWIFT Prime (51.9 vs. 35.5%, p = 0.02), and REVASCAT (51.9 vs. 28.2%, p = 0.0003) controls. Symptomatic intracranial hemorrhage definitions varied across the different studies with rates ranging from 2.7% (ESCAPE) to 11.9% (NILG). The NILG 90-day mortality (24

  1. Compression creep rupture of an E-glass/vinyl ester composite subjected to combined mechanical and fire loading conditions

    NASA Astrophysics Data System (ADS)

    Boyd, Steven Earl

    Polymer matrix composites are seeing increasing use in structural systems (e.g. ships, bridges) and require a quantitative basis for describing their performance under combined mechanical load and fire. Although much work has been performed to characterize the flammability, fire resistance and toxicity of these composite systems, an understanding of the structural response of sandwich type structures and laminate panels under combined mechanical and thermal loads (simulating fire conditions) is still largely unavailable. Therefore a research effort to develop a model to describe the structural response of these glass/vinyl esters systems under fire loading conditions is relevant to the continuing and future application of polymer matrix composites aboard naval ships. The main goal of the effort presented here is to develop analytical models and finite element analysis methods and tools to predict limit states such as local compression failures due to micro-buckling, residual strength and times to failure for composite laminates at temperatures in the vicinity of the glass transition where failure is controlled by viscoelastic effects. Given the importance of compression loading to a structure subject to fire exposure, the goals of this work are succinctly stated as the: (a) Characterization of the non-linear viscoelastic and viscoplastic response of the E-glass/vinyl ester composite above Tg. (b) Description of the laminate compression mechanics as a function of stress and temperature including viscoelasticity. (c) Viscoelastic stress analysis of a laminated panel ([0/+45/90/-45/0] S) using classical lamination theory (CLT). Three manuscripts constitute this dissertation which is representative of the three steps listed above. First, a detailed characterization of the nonlinear thermoviscoelastic response of Vetrotex 324/Derakane 510A--40 through Tg was conducted using the Time--Temperature--Stress--Superposition Principle (TTSSP) and Zapas--Crissman model. Second

  2. Comparison between effectiveness of Mechanical and Manual Traction combined with mobilization and exercise therapy in Patients with Cervical Radiculopathy

    PubMed Central

    Bukhari, Syed Rehan Iftikhar; Shakil-ur-Rehman, Syed; Ahmad, Shakeel; Naeem, Aamer

    2016-01-01

    Background and Objective: Cervical radiculopathy is a common neuro-musculo-skeletal disorder causing pain and disability. Traction is part of the evidence based manual physical therapy management due to its mechanical nature, type of traction and parameters related to its applicability and are still to be explored more through research. Our objective was to determine the Effects of Mechanical versus Manual Traction in Manual Physical Therapy combined with segmental mobilization and exercise therapy in the physical therapy management of Patients with Cervical Radiculopathy. Methods: This randomized control trial was conducted at department of physical therapy and rehabilitation, Rathore Hospital Faisalabad, from February to July 2015. Inclusion criteria were both male and female patients with evident symptoms of cervical spine radiculopathy and age ranged between 20-70 years. The exclusion criteria were Patients with history of trauma, neck pain without radiculopathy, aged less than 20 and more than 70. A total of 72 patients with cervical radiculopathy were screened out as per the inclusion criteria, 42 patients were randomly selected and placed into two groups by toss and trial method, and only 36 patients completed the study, while 6 dropped out. The mechanical traction was applied in group A and manual traction in group B along with common intervention of segmental mobilization and exercise therapy in both groups for 6 weeks. The patient’s outcomes were assessed by self reported NPRS and NDI at the baseline and after completion of 06 weeks exercise program at 3 days per week. The data was analyzed through SPSS version-21, and paired T test was applied at 95% level significance to determine the statistical deference between two groups. Results: Clinically the group of patients treated with mechanical traction managed pain (mean pre 6.26, mean post 1.43), and disability (mean pre 24.43 and mean post 7.26) more effectively as compared with the group of patients

  3. Mechanical Revascularization for Acute Ischemic Stroke: A Single-Center, Retrospective Analysis

    SciTech Connect

    Jeromel, Miran Milosevic, Z. V. Kocijancic, I. J. Lovric, D.; Svigelj, V. Zvan, B.

    2013-04-15

    BackgroundEndovascular mechanical revascularization (thrombectomy) is an increasingly used method for intracranial large vessel recanalization in acute stroke. The purpose of the study was to analyze the recanalization rate, clinical outcome, and complication rate in our stroke patients treated with mechanical revascularization. A total of 57 patients with large vessel stroke (within 3 h for anterior and 12 h for posterior circulation) were treated with mechanical revascularization at a single center during 24 months. The primary goal of endovascular treatment using different mechanical devices was recanalization of the occluded vessel. Recanalization rate (reported as thrombolysis in cerebral infarction [TICI] score), clinical outcome (reported as National Institutes of Health Stroke Scale [NIHSS] score and modified Rankin scale [mRS] score), as well as periprocedural complications were analyzed. The mean age of the patients was 63.1 {+-} 12.9 years, with baseline median NIHSS score of 14 (interquartile range, 9.5-19). Successful recanalization (TICI 2b or 3) was achieved in 41 (72 %) patients. Twenty patients (35 %) presented with favorable outcome (mRS {<=}2) 30 days after stroke. Overall, significant neurological improvement ({>=}4 NIHSS point reduction) occurred in 36 (63 %) patients. A clinically significant procedure-related adverse events (vessel disruption, peri/postprocedural intracranial bleeding) defined with decline in NIHSS of {>=}4 or death occurred in three (5 %) patients. The study showed a high recanalization rate with improved clinical outcome and a low rate of periprocedural complications in our stroke patients treated with mechanical revascularization. Therefore, we could conclude that endovascular revascularization (primary or in combination with a bridging thrombolysis) was an effective and safe procedure for intracranial large vessel recanalization in acute stroke.

  4. A possible mechanism of action of danazol and an ethinylestradiol/norgestrel combination used as postcoital contraceptive agents.

    PubMed

    Rowlands, S; Kubba, A A; Guillebaud, J; Bounds, W

    1986-06-01

    Twenty-seven women requesting postcoital contraception were randomly allocated to take an ethinylestradiol/dl-norgestrel combination or danazol. Urine specimens were assayed for luteinising hormone (LH) and pregnanediol-3-glucuronide (P3G) levels from the day of the postcoital treatment to the next period. In addition, the urine samples of these recruits and 12 additional women were assayed for the Beta-subunit of human chorionic gonadotropin (B-hCG). A consistent pattern of alteration in urinary steroids was lacking, indicating a heterogeneous effect on ovarian function. There was no evidence of early pregnancy in successfully treated cases. We suggest that the main mechanism of action of these drugs is at the endometrial level. PMID:3533419

  5. Traumatic cervical cord transection without facet dislocations--a proposal of combined hyperflexion-hyperextension mechanism: a case report.

    PubMed

    Cha, Yoo-Hyun; Cho, Tai-Hyoung; Suh, Jung-Keun

    2010-08-01

    A patient is presented with a cervical spinal cord transection which occurred after a motor vehicle accident in which the air bag deployed and the seat belt was not in use. The patient had complete quadriplegia below the C5 level and his imaging study showed cervical cord transection at the level of the C5/6 disc space with C5, C6 vertebral bodies and laminar fractures. He underwent a C5 laminectomy and a C4-7 posterior fusion with lateral mass screw fixation. Previous reports have described central cord syndromes occurring in hyperextension injuries, but in adults, acute spinal cord transections have only developed after fracture-dislocations of the spine. A case involving a post-traumatic spinal cord transection without any evidence of radiologic facet dislocations is reported. Also, we propose a combined hyperflexion-hyperextension mechanism to explain this type of injury.

  6. Increasing reliability of gas-air systems of piston and combined internal combustion engines by improving thermal and mechanic flow characteristics

    NASA Astrophysics Data System (ADS)

    Brodov, Yu. M.; Grigor'ev, N. I.; Zhilkin, B. P.; Plotnikov, L. V.; Shestakov, D. S.

    2015-12-01

    Results of experimental study of thermal and mechanical characteristics of gas exchange flow in piston and combined engines are presented. Ways for improving intake and exhaust processes to increase reliability of gas-air engine systems are proposed.

  7. Survival mechanism of Escherichia coli O157:H7 against combined treatment with acetic acid and sodium chloride.

    PubMed

    Lee, Sun-Young; Kang, Dong-Hyun

    2016-05-01

    The combination of salt and acid is commonly used in the production of many foods, including pickles and fermented foods. However, in our previous studies, the addition of salt significantly reduced the inhibitory effect of acetic acid on Escherichia coli O157:H7 in laboratory media and pickled cucumbers. Therefore, this study was conducted to determine the mechanism by which salt confers resistance against acetic acid in E. coli O157:H7. The addition of high concentrations (up to 9% or 15% [w/v]) of salt increased the resistance of E. coli O157:H7 to acetic acid treatment. Combined treatment with acetic acid and salt showed varying results among different bacterial strains (an antagonistic effect for E. coli O157:H7 and Shigella and a synergistic effect for Listeria monocytogenes and Staphylococcus aureus). The addition of salt increased the cytoplasmic pH of E. coli O157:H7, but decreased the cytoplasmic pH of L. monocytogenes and S. aureus on treatment with acetic acid. Therefore, the addition of salt increases the acid resistance of E. coli O157:H7 possibly by increasing its acid resistance response and consequently preventing the acidification of its cytoplasm by organic acids.

  8. Plasma metabolomics combined with lipidomics profiling reveals the potential antipyretic mechanisms of Qingkailing injection in a rat model.

    PubMed

    Qin, Lingling; Zhang, Zhixin; Guo, Mingxing; Zhang, Qingqing; Wang, Qing; Lu, Zhiwei; Zhao, Huizhen; Liu, Yuehong; Fu, Shuang; Wang, Meiling; Gao, Xiaoyan

    2016-07-25

    Qingkailing injection (QKLI) has a notable antipyretic effect and is widely used in China as a clinical emergency medicine. To elucidate the pharmacological action thoroughly, following the investigation of the urine metabolome and hypothalamus metabolome, plasma metabolomics combined with lipidomics profiling of the QKLI antipyretic effect in a rat model is described in this paper. Compared with pure metabolomics profiling, this non-targeted plasma metabolomics combined with lipidomics profiling based on ultra-performance liquid chromatography-coupled with quadrupole time-of-flight mass spectrometry (UPLC Q-TOF/MS) could be used for a large-scale detection of features in plasma samples. The results showed that 15 metabolites at the 1 h time point and 19 metabolites at the 2 h time point after QKLI administration were associated with the antipyretic effect of QKLI, including amino acid, phosphatidylcholine and lysophosphatidylcholine. The metabolism pathway analysis revealed that the potential biomarkers, which were important for the antipyretic mechanism of QKLI, were closely responsible for correcting the perturbed pathways of amino acid metabolism and lipid metabolism. In conclusion, the use of complementary UPLC Q-TOF/MS based metabolomics and lipidomics allows for the discovery of new potential plasma biomarkers in the QKLI antipyretic process and the associated pathways, and aided in advancing the understanding of the holism and synergism of the Chinese drug. PMID:27208622

  9. [THE ENVIRONMENTAL BASES AND MECHANISM FOR NATURAL OPISTHORCHIASIS FOCUS PULSATION IN THE COMBINED FOCUS OF OPISTHORCHIASIS AND TULAREMIA].

    PubMed

    Ushakov, A V

    2015-01-01

    A cyclic change in the epizootic activity of a tularemia activity underlies the mechanism of natural opisthorchiasis focus pulsation in the combined focus of opisthorchiasis and tularemia in the ecosystem of the Konda River. This is due to mass breeding and depression in the water vole (Arvicola terrestris) population. The mass breeding is predetermined by high population reproduction constants. The rodents' potential fecundity occurs with the high capacity of lands, which is caused by the hydrological regime of rivers. The size depression is predetermined by the epizootics of tularemia. The water vole is a host of the pathogens of opisthorchiasis and tularemia. So the mass rodent breeding in the combined infection and invasion focus causes an increase in the number of real invasion sources. The epizootic of tularemia is responsible for elimination of these invasion sources and for decreases in the flow of invasion material, the infection rate of Codiella and hence the amount of their produced cercarae, the extensive and intensive indicators of fish contamination, and the intensity of an epizootic process in the opisthorchiasis focus. PMID:26152031

  10. [THE ENVIRONMENTAL BASES AND MECHANISM FOR NATURAL OPISTHORCHIASIS FOCUS PULSATION IN THE COMBINED FOCUS OF OPISTHORCHIASIS AND TULAREMIA].

    PubMed

    Ushakov, A V

    2015-01-01

    A cyclic change in the epizootic activity of a tularemia activity underlies the mechanism of natural opisthorchiasis focus pulsation in the combined focus of opisthorchiasis and tularemia in the ecosystem of the Konda River. This is due to mass breeding and depression in the water vole (Arvicola terrestris) population. The mass breeding is predetermined by high population reproduction constants. The rodents' potential fecundity occurs with the high capacity of lands, which is caused by the hydrological regime of rivers. The size depression is predetermined by the epizootics of tularemia. The water vole is a host of the pathogens of opisthorchiasis and tularemia. So the mass rodent breeding in the combined infection and invasion focus causes an increase in the number of real invasion sources. The epizootic of tularemia is responsible for elimination of these invasion sources and for decreases in the flow of invasion material, the infection rate of Codiella and hence the amount of their produced cercarae, the extensive and intensive indicators of fish contamination, and the intensity of an epizootic process in the opisthorchiasis focus.

  11. Separation of atmospheric, oceanic and hydrological polar motion excitation mechanisms based on a combination of geometric and gravimetric space observations

    NASA Astrophysics Data System (ADS)

    Göttl, F.; Schmidt, M.; Seitz, F.; Bloßfeld, M.

    2015-04-01

    The goal of our study is to determine accurate time series of geophysical Earth rotation excitations to learn more about global dynamic processes in the Earth system. For this purpose, we developed an adjustment model which allows to combine precise observations from space geodetic observation systems, such as Satellite Laser Ranging (SLR), Global Navigation Satellite Systems, Very Long Baseline Interferometry, Doppler Orbit determination and Radiopositioning Integrated on Satellite, satellite altimetry and satellite gravimetry in order to separate geophysical excitation mechanisms of Earth rotation. Three polar motion time series are applied to derive the polar motion excitation functions (integral effect). Furthermore we use five time variable gravity field solutions from Gravity Recovery and Climate Experiment to determine not only the integral mass effect but also the oceanic and hydrological mass effects by applying suitable filter techniques and a land-ocean mask. For comparison the integral mass effect is also derived from degree 2 potential coefficients that are estimated from SLR observations. The oceanic mass effect is also determined from sea level anomalies observed by satellite altimetry by reducing the steric sea level anomalies derived from temperature and salinity fields of the oceans. Due to the combination of all geodetic estimated excitations the weaknesses of the individual processing strategies can be reduced and the technique-specific strengths can be accounted for. The formal errors of the adjusted geodetic solutions are smaller than the RMS differences of the geophysical model solutions. The improved excitation time series can be used to improve the geophysical modeling.

  12. Material combinations and parametric study of thermal and mechanical performance of pyramidal core sandwich panels used for hypersonic aircrafts

    NASA Astrophysics Data System (ADS)

    Zhang, Ruiping; Zhang, Xiaoqing; Lorenzini, Giulio; Xie, Gongnan

    2016-11-01

    A novel kind of lightweight integrated thermal protection system, named pyramidal core sandwich panel, is proposed to be a good safeguard for hypersonic aircrafts in the current study. Such system is considered as not only an insulation structure but also a load-bearing structure. In the context of design for hypersonic aircrafts, an efficient optimization should be paid enough attention. This paper concerns with the homogenization of the proposed pyramidal sandwich core panel using two-dimensional model in subsequent research for material selection. According to the required insulation performance and thermal-mechanical properties, several suitable material combinations are chosen as candidates for the pyramidal core sandwich panel by adopting finite element analysis and approximate response surface. To obtain lightweight structure with an excellent capability of heat insulation and load-bearing, an investigation on some specific design variables, which are significant for thermal-mechanical properties of the structure, is performed. Finally, a good balance between the insulation performance, the capability of load-bearing and the lightweight has attained.

  13. Combined Effect of Mechanical Grooving and Stain-Etched Surface on Optical and Electrical Properties of Crystalline Silicon Substrates

    NASA Astrophysics Data System (ADS)

    Zarroug, Ahmed; Derbali, Lotfi; Ouertani, Rachid; Dimassi, Wissem; Ezzaouia, Hatem

    2014-05-01

    This paper investigates the combined effect of mechanical grooving and porous silicon (PS) on the front surface reflectance and the electronic properties of crystalline silicon substrates. Mechanical surface texturization leads to reduce the cell reflectance, enhance the light trapping and augment the carrier collection probability. PS was introduced as an efficient antireflective coating (ARC) onto the front surface of crystalline silicon solar cell. Micro-periodic V-shaped grooves were made by means of a micro-groove machining process prior to junction formation. Subsequently, wafers were subjected to an isotropic potassium hydroxide (KOH) etching so that the V-shape would be turned to a U-shape. We found that the successive treatment of silicon surfaces with stain-etching, grooving then alkaline etching enhances the absorption of the textured surface, and decreases the reflectance from 35% to 7% in the 300-1200 nm wavelength range. We obtained a significant increase in the overall light path that generates the building up of the light trapping inside the substrate. We found an improvement in the illuminated I-V characteristics and an increase in the minority carrier lifetime τeff. Such a simple method was adopted to effectively reinforce the overall device performance of crystalline silicon-based solar cells.

  14. A combined cryo-EM and molecular dynamics approach reveals the mechanism of ErmBL-mediated translation arrest.

    PubMed

    Arenz, Stefan; Bock, Lars V; Graf, Michael; Innis, C Axel; Beckmann, Roland; Grubmüller, Helmut; Vaiana, Andrea C; Wilson, Daniel N

    2016-01-01

    Nascent polypeptides can induce ribosome stalling, regulating downstream genes. Stalling of ErmBL peptide translation in the presence of the macrolide antibiotic erythromycin leads to resistance in Streptococcus sanguis. To reveal this stalling mechanism we obtained 3.6-Å-resolution cryo-EM structures of ErmBL-stalled ribosomes with erythromycin. The nascent peptide adopts an unusual conformation with the C-terminal Asp10 side chain in a previously unseen rotated position. Together with molecular dynamics simulations, the structures indicate that peptide-bond formation is inhibited by displacement of the peptidyl-tRNA A76 ribose from its canonical position, and by non-productive interactions of the A-tRNA Lys11 side chain with the A-site crevice. These two effects combine to perturb peptide-bond formation by increasing the distance between the attacking Lys11 amine and the Asp10 carbonyl carbon. The interplay between drug, peptide and ribosome uncovered here also provides insight into the fundamental mechanism of peptide-bond formation. PMID:27380950

  15. A combined cryo-EM and molecular dynamics approach reveals the mechanism of ErmBL-mediated translation arrest

    NASA Astrophysics Data System (ADS)

    Arenz, Stefan; Bock, Lars V.; Graf, Michael; Innis, C. Axel; Beckmann, Roland; Grubmüller, Helmut; Vaiana, Andrea C.; Wilson, Daniel N.

    2016-07-01

    Nascent polypeptides can induce ribosome stalling, regulating downstream genes. Stalling of ErmBL peptide translation in the presence of the macrolide antibiotic erythromycin leads to resistance in Streptococcus sanguis. To reveal this stalling mechanism we obtained 3.6-Å-resolution cryo-EM structures of ErmBL-stalled ribosomes with erythromycin. The nascent peptide adopts an unusual conformation with the C-terminal Asp10 side chain in a previously unseen rotated position. Together with molecular dynamics simulations, the structures indicate that peptide-bond formation is inhibited by displacement of the peptidyl-tRNA A76 ribose from its canonical position, and by non-productive interactions of the A-tRNA Lys11 side chain with the A-site crevice. These two effects combine to perturb peptide-bond formation by increasing the distance between the attacking Lys11 amine and the Asp10 carbonyl carbon. The interplay between drug, peptide and ribosome uncovered here also provides insight into the fundamental mechanism of peptide-bond formation.

  16. Subchromoplast Sequestration of Carotenoids Affects Regulatory Mechanisms in Tomato Lines Expressing Different Carotenoid Gene Combinations[C][W

    PubMed Central

    Nogueira, Marilise; Mora, Leticia; Enfissi, Eugenia M.A.; Bramley, Peter M.; Fraser, Paul D.

    2013-01-01

    Metabolic engineering of the carotenoid pathway in recent years has successfully enhanced the carotenoid contents of crop plants. It is now clear that only increasing biosynthesis is restrictive, as mechanisms to sequestrate these increased levels in the cell or organelle should be exploited. In this study, biosynthetic pathway genes were overexpressed in tomato (Solanum lycopersicum) lines and the effects on carotenoid formation and sequestration revealed. The bacterial Crt carotenogenic genes, independently or in combination, and their zygosity affect the production of carotenoids. Transcription of the pathway genes was perturbed, whereby the tissue specificity of transcripts was altered. Changes in the steady state levels of metabolites in unrelated sectors of metabolism were found. Of particular interest was a concurrent increase of the plastid-localized lipid monogalactodiacylglycerol with carotenoids along with membranous subcellular structures. The carotenoids, proteins, and lipids in the subchromoplast fractions of the transgenic tomato fruit with increased carotenoid content suggest that cellular structures can adapt to facilitate the sequestration of the newly formed products. Moreover, phytoene, the precursor of the pathway, was identified in the plastoglobule, whereas the biosynthetic enzymes were in the membranes. The implications of these findings with respect to novel pathway regulation mechanisms are discussed. PMID:24249831

  17. A combined cryo-EM and molecular dynamics approach reveals the mechanism of ErmBL-mediated translation arrest

    PubMed Central

    Arenz, Stefan; Bock, Lars V.; Graf, Michael; Innis, C. Axel; Beckmann, Roland; Grubmüller, Helmut; Vaiana, Andrea C.; Wilson, Daniel N.

    2016-01-01

    Nascent polypeptides can induce ribosome stalling, regulating downstream genes. Stalling of ErmBL peptide translation in the presence of the macrolide antibiotic erythromycin leads to resistance in Streptococcus sanguis. To reveal this stalling mechanism we obtained 3.6-Å-resolution cryo-EM structures of ErmBL-stalled ribosomes with erythromycin. The nascent peptide adopts an unusual conformation with the C-terminal Asp10 side chain in a previously unseen rotated position. Together with molecular dynamics simulations, the structures indicate that peptide-bond formation is inhibited by displacement of the peptidyl-tRNA A76 ribose from its canonical position, and by non-productive interactions of the A-tRNA Lys11 side chain with the A-site crevice. These two effects combine to perturb peptide-bond formation by increasing the distance between the attacking Lys11 amine and the Asp10 carbonyl carbon. The interplay between drug, peptide and ribosome uncovered here also provides insight into the fundamental mechanism of peptide-bond formation. PMID:27380950

  18. Combined effects of proinflammatory cytokines and intermittent cyclic mechanical strain in inhibiting osteogenicity in human periodontal ligament cells.

    PubMed

    Sun, Chaofan; Chen, Lijiao; Shi, Xinlian; Cao, Zhensheng; Hu, Bibo; Yu, Wenbin; Ren, Manman; Hu, Rongdang; Deng, Hui

    2016-09-01

    Mechanical strain plays an important role in bone formation and resorption during orthodontic tooth movement. The mechanism has not been fully studied, and the process becomes complex with increased amounts of periodontal patients seeking orthodontic care. Our aims were to elucidate the combined effects of proinflammatory cytokines and intermittent cyclic strain (ICS) on the osteogenic capacity of human periodontal ligament cells. Cultured human periodontal ligament cells were exposed to proinflammatory cytokines (interleukin-1β 5 ng/mL and tumor necrosis factor-α 10 ng/mL) for 1 and 5 days, and ICS (0.5 Hz, 12% elongation) was applied for 4 h per day. The autocrine of inflammatory cytokines was measured by enzyme-linked immunosorbent assay. The expression of osteoblast markers runt-related transcription factor 2 and rabbit collagen type I was determined using real-time polymerase chain reaction and Western blot. The osteogenic capacity was also detected by alkaline phosphatase (ALP) staining, ALP activity, and alizarin red staining. We demonstrated that ICS impaired the osteogenic capacity of human periodontal ligament cells when incubated with proinflammatory cytokines, as evidenced by the low expression of ALP staining, low ALP activity, reduced alizarin red staining, and reduced osteoblast markers. These data, for the first time, suggest that ICS has a negative effect on the inductive inhibition of osteogenicity in human PDL cells mediated by proinflammatory cytokines. PMID:27357508

  19. Material combinations and parametric study of thermal and mechanical performance of pyramidal core sandwich panels used for hypersonic aircrafts

    NASA Astrophysics Data System (ADS)

    Zhang, Ruiping; Zhang, Xiaoqing; Lorenzini, Giulio; Xie, Gongnan

    2016-07-01

    A novel kind of lightweight integrated thermal protection system, named pyramidal core sandwich panel, is proposed to be a good safeguard for hypersonic aircrafts in the current study. Such system is considered as not only an insulation structure but also a load-bearing structure. In the context of design for hypersonic aircrafts, an efficient optimization should be paid enough attention. This paper concerns with the homogenization of the proposed pyramidal sandwich core panel using two-dimensional model in subsequent research for material selection. According to the required insulation performance and thermal-mechanical properties, several suitable material combinations are chosen as candidates for the pyramidal core sandwich panel by adopting finite element analysis and approximate response surface. To obtain lightweight structure with an excellent capability of heat insulation and load-bearing, an investigation on some specific design variables, which are significant for thermal-mechanical properties of the structure, is performed. Finally, a good balance between the insulation performance, the capability of load-bearing and the lightweight has attained.

  20. Characterization of carbapenem resistance mechanisms in Klebsiella pneumoniae and in vitro synergy of the colistin-meropenem combination.

    PubMed

    Krishnappa, Lakshmana Gowda; Marie, Mohammed Ali M; Al Sheikh, Yazeed A

    2015-10-01

    In this prospective study, consecutive isolates of Klebsiella pneumoniae were tested for different mechanisms of carbapenem resistance using the modified Hodge test (MHT), Rosco Neo-Sensitabs (ROSCO). Phenylalanine arginine beta-naphthylamide assay (PABN) inhibitor-based test was done on isolates in which the mechanism of resistance was not identifiable by the ROSCO. Among 105 selected isolates, carbapenemase production was noted in 100 (95%) by MHT and ROSCO showed 97 (92·4%) inhibition with dipicolinic acid signifying the production of MBL. PCR amplification was positive in 90 (86%) isolates for bla(NDM-1) and 46 (44%) isolates for bla(OXA-48). 54 (51%) isolates were positive for bla(CTX-M) and all belonged to bla(CTX-M) group 1. Isolates co produced bla(OXA-48) (31/105, 30%) and bla(CTX-M) (40/105, 38%) in combination with the carbapenemase (bla(NDM-1)) gene. Five colistin-resistant isolates were positive for bla(OXA-48). Eight isolates did not show inhibition with any of the inhibitor containing disks and found to be positive for bla(OXA-48). Isolates were tested for colistin-meropenem synergy and detection rate was higher by the checkerboard (48%) than E-test method (35%). Our study necessitates continuous surveillance to recognize the predominant machinery of resistance in a particular geographical region to formulate effective control measures.

  1. Separation of atmospheric, oceanic and hydrological polar motion excitation mechanisms by a combination of geometric and gravimetric space observations

    NASA Astrophysics Data System (ADS)

    Göttl, Franziska; Schmidt, Michael; Seitz, Florian; Blossfeld, Mathis

    2014-05-01

    Redistribution and motion of masses within and between the individual subsystems of the Earth cause variations of the orientation of the Earth axis with respect to an Earth-fixed reference frame (polar motion and length-of-day variations). Whereas the integral effect of Earth rotation is precisely measured by geometric space techniques, such as Satellite Laser Ranging (SLR), Very Long Baseline Interferometry (VLBI), Global Navigation Satellite Systems (GNSS) and Doppler Orbit determination and Radiopositioning Integrated on Satellite (DORIS), the separation into individual excitation mechanisms remains a challenge. Commonly, individual geophysical excitation mechanisms of Earth rotation are derived from geophysical models. Due to the fact that geophysical models are afflicted with uncertainties, results derived from different model show large discrepancies. Here we present an adjustment model which allows to combine precise observations from space geodetic observation systems (SLR, VLBI, GNSS, DORIS, satellite altimetry and satellite gravimetry) in order to separate geophysical excitation mechanisms of the Earth rotation. Time variable gravity field solutions from GRACE (Gravity Recovery and Climate Experiment) are used to determine not only the integral mass effect but also the oceanic and hydrological mass effects by applying suitable filter techniques and land-ocean-masks. Furthermore the oceanic mass effect is determined from sea level anomalies as observed by cross-calibrated multi-mission altimetry. Due to the fact that sea level anomalies are not only caused by mass variations but also by volume changes (steric effect), these steric sea level anomalies need to be reduced using appropriate models. We show that through the combination weaknesses of the individual processing strategies can be compensated and the technique specific strengths can be optimally accounted for. This way, excitation functions of atmospheric, oceanic and hydrological mass effects and

  2. Molecular mechanisms for inhibition of colon cancer cells by combined epigenetic-modulating epigallocatechin gallate and sodium butyrate.

    PubMed

    Saldanha, Sabita N; Kala, Rishabh; Tollefsbol, Trygve O

    2014-05-15

    Bioactive compounds are considered safe and have been shown to alter genetic and epigenetic profiles of tumor cells. However, many of these changes have been reported at molecular concentrations higher than physiologically achievable levels. We investigated the role of the combinatorial effects of epigallocatechin gallate (EGCG), a predominant polyphenol in green tea, and sodium butyrate (NaB), a dietary microbial fermentation product of fiber, in the regulation of survivin, which is an overexpressed anti-apoptotic protein in colon cancer cells. For the first time, our study showed that the combination treatment induced apoptosis and cell cycle arrest in RKO, HCT-116 and HT-29 colorectal cancer cells. This was found to be regulated by the decrease in HDAC1, DNMT1, survivin and HDAC activity in all three cell lines. A G2/M arrest was observed for RKO and HCT-116 cells, and G1 arrest for HT-29 colorectal cancer cells for combinatorial treatment. Further experimentation of the molecular mechanisms in RKO colorectal cancer (CRC) cells revealed a p53-dependent induction of p21 and an increase in nuclear factor kappa B (NF-κB)-p65. An increase in double strand breaks as determined by gamma-H2A histone family member X (γ-H2AX) protein levels and induction of histone H3 hyperacetylation was also observed with the combination treatment. Further, we observed a decrease in global CpG methylation. Taken together, these findings suggest that at low and physiologically achievable concentrations, combinatorial EGCG and NaB are effective in promoting apoptosis, inducing cell cycle arrest and DNA-damage in CRC cells.

  3. The clinical effect and relevant mechanism of combined sorafenib and radiofrequency ablation in the treatment of early small hepatocellular carcinoma

    PubMed Central

    Yan, Shi-Yan; Zhang, Yi; Sun, Chao; Cao, Hai-Xia; Li, Guang-Ming; Wang, Yu-Qin; Fan, Jian-Gao

    2016-01-01

    The number of cases with hepatocellular carcinoma (HCC) are on the increase. The aim of the present study was to investigate the clinical effect and relevant mechanism of combined sorafenib and radiofrequency ablation (RFA) in the treatment of the early small HCC. A total of 120 cases of patients with small HCC that presented during the period of May 2007 to June 2010 were selected and divided into the surgery (n=60) and RF (n=60) groups according to the treatment method employed. The surgery group was treated with a laparotomy resection and the RF group was treated with combined sorafenib and RFA, and a comparative analysis was made between the two groups with regard to recurrence rates, adverse reactions, and survival rates. After treatment of 1 month, the radical effective rate of the surgery and RF groups was 100%. Contrast-enhanced ultrasound images of the patients in the RF group were taken. During the 5-year follow-up, the tumor recurrence rate in the surgery group was 18.3%, significantly lower than that in the RF group where the tumor recurrence rate was 38.3% (P<0.05). The occurrence rate of postoperative pain, fever, abdominal bleeding, infection, and other complications of patients in the surgery group was significantly higher than the complication occurrence rate (P<0.05) of the patients in the RF group. The average survival time of the patients in the surgery group was 51.2±1.5 months and the survival rates during the first, third and fifth year were 90.7, 71.5 and 56.7%, respectively. Additionally, the average survival time of the patients in the RF group was 64.6±2.4 months and the survival rates during the first, third and fifth year were 91.1, 72.8 and 57.5%, respectively. The difference between the two groups was not statistically significant. The tumor-free survival rates in the surgery group during the first, third and fifth year were 87.8, 44.3 and 33.2%, respectively, while the tumor-free survival rates in the RF group during the first

  4. A Combination of Chemometrics and Quantum Mechanics Methods Applied to Analysis of Femtosecond Transient Absorption Spectrum of Ortho-Nitroaniline.

    PubMed

    Yi, Jing; Xiong, Ying; Cheng, Kemei; Li, Menglong; Chu, Genbai; Pu, Xuemei; Xu, Tao

    2016-01-19

    A combination of the advanced chemometrics method with quantum mechanics calculation was for the first time applied to explore a facile yet efficient analysis strategy to thoroughly resolve femtosecond transient absorption spectroscopy of ortho-nitroaniline (ONA), served as a model compound of important nitroaromatics and explosives. The result revealed that the ONA molecule is primarily excited to S3 excited state from the ground state and then ultrafast relaxes to S2 state. The internal conversion from S2 to S1 occurs within 0.9 ps. One intermediate state S* was identified in the intersystem crossing (ISC) process, which is different from the specific upper triplet receiver state proposed in some other nitroaromatics systems. The S1 state decays to the S* one within 6.4 ps and then intersystem crossing to the lowest triplet state within 19.6 ps. T1 was estimated to have a lifetime up to 2 ns. The relatively long S* state and very long-lived T1 one should play a vital role as precursors to various nitroaromatic and explosive photoproducts.

  5. The combined effect of dismantling for steam sterilization and aging on the accuracy of spring-style mechanical torque devices

    PubMed Central

    Mahshid, Minoo; Sadr, Seyed Jalil; Fayyaz, Ali; Kadkhodazadeh, Mahdi

    2013-01-01

    Purpose This study aimed to assess the combined effect of dismantling before sterilization and aging on the accuracy (±10% of the target torque) of spring-style mechanical torque devices (S-S MTDs). Methods Twenty new S-SMTDs from two different manufacturers (Nobel Biocare and Straumann: 10 of each type) were selected and divided into two groups, namely, case (group A) and control (group B). For sterilization, 100 cycles of autoclaving were performed in 100 sequences. In each sequence, 10 repetitions of peak torque values were registered for aging. To measure and assess the output of each device, a Tohnichi torque gauge was used (P<0.05). Results Before steam sterilization, all of the tested devices stayed within 10% of their target values. After 100 cycles of steam sterilization and aging with or without dismantling of the devices, the Nobel Biocare devices stayed within 10% of their target torque. In the Straumann devices, despite the significant difference between the peak torque and target torque values, the absolute error values stayed within 10% of their target torque. Conclusion Within the limitations of this study, there was no significant difference between the mean and absolute value of error between Nobel Biocare and Straumann S-S MTDs. PMID:24236244

  6. Combining Atomic Force Microscopy and Depth-Sensing Instruments for the Nanometer-Scale Mechanical Characterization of Soft Matter

    NASA Astrophysics Data System (ADS)

    Tranchida, Davide; Piccarolo, Stefano

    Complex materials exhibit a hierarchical structure where a gradient of features on nanometer scale is induced by the synthetic route eventually enhanced by the loading condition. The nanometer scale at which individual components arrange, determining their properties, is a current challenge of mechanical testing. In this work, a survey on nanoindentation is outlined based on the comparison of results obtained by Atomic Force Microscopy and Depth-Sensing Instruments and their combination. An Atomic Force Microscope equipped with a Force Transducer gives indeed the possibility to scan the sample surface in contact mode, thereby allowing one to choose a suitable position for the nanoindentation, as well as imaging the residual imprint left on the sample. The analysis of the applied load vs. penetration depth curve, also called force curve, shows the limitations of current approaches to determine elastic moduli of compliant viscoelastic materials. Significant deviations from the expected values are observed even after optimizing testing conditions, so as to minimize the artifacts like viscoelastic effects or pile-up. As rigorous approaches are yet to be applied to the interpretation of force curves accounting also of viscoelastic material behavior, an empirical calibration recently proposed by the authors is verified against a set of data on model samples spanning a range of moduli, typical of compliant materials and close to each other, so as to challenge the resolution potential of this method, as well as others in use in the literature.

  7. A Combination of Chemometrics and Quantum Mechanics Methods Applied to Analysis of Femtosecond Transient Absorption Spectrum of Ortho-Nitroaniline

    PubMed Central

    Yi, Jing; Xiong, Ying; Cheng, Kemei; Li, Menglong; Chu, Genbai; Pu, Xuemei; Xu, Tao

    2016-01-01

    A combination of the advanced chemometrics method with quantum mechanics calculation was for the first time applied to explore a facile yet efficient analysis strategy to thoroughly resolve femtosecond transient absorption spectroscopy of ortho-nitroaniline (ONA), served as a model compound of important nitroaromatics and explosives. The result revealed that the ONA molecule is primarily excited to S3 excited state from the ground state and then ultrafast relaxes to S2 state. The internal conversion from S2 to S1 occurs within 0.9 ps. One intermediate state S* was identified in the intersystem crossing (ISC) process, which is different from the specific upper triplet receiver state proposed in some other nitroaromatics systems. The S1 state decays to the S* one within 6.4 ps and then intersystem crossing to the lowest triplet state within 19.6 ps. T1 was estimated to have a lifetime up to 2 ns. The relatively long S* state and very long-lived T1 one should play a vital role as precursors to various nitroaromatic and explosive photoproducts. PMID:26781083

  8. Combined effects of wetting, drying, and microcrystalline cellulose type on the mechanical strength and disintegration of pellets.

    PubMed

    Balaxi, Maria; Nikolakakis, Ioannis; Kachrimanis, Kyriakos; Malamataris, Stavros

    2009-02-01

    Effects of wetting and drying conditions on micromeritic, mechanical and disintegration properties of microcrystalline cellulose (MCC) pellets were evaluated. Extrusion/spheronization and three drying methods (fluidized bed, microwaves, and freeze drying) were applied using two wetting liquids (water or water-isopropanol 60:40 w/w) and three MCC types: (standard, silicified, and modified). Additionally, the effects of drying method were compared on highly porous pellets prepared by the incorporation and extraction of pore former (NaCl). It was found that the drying method has the greatest effect on the pellet size and porosity followed by the wetting liquid. The modification of MCC resulted in reduced water retention ability, implying hornification, increased porosity, reduced resistance to deformation and tensile strength of pellets. The disintegration time also decreased markedly due to the modification but only in the low porosity range <37%. Silicification increased greatly the disintegration time of the low porosity pellets (<14%). Combination of water-isopropanol, freeze drying and modified MCC gave the greatest increase in pellet size and porosity. The increase in pellet porosity caused exponential reduction in the resistance to deformation, tensile strength and disintegration time, as expected. Compared to fluidized bed, the freeze drying resulted in 20-30% higher porosity for pellets prepared without pore former and 6% for those with pore former, indicating the possibility of preparing highly porous pellets by employing freeze drying. PMID:18548618

  9. Gross mechanical efficiency of the combined arm-leg (Cruiser) ergometer: a comparison with the bicycle ergometer and handbike.

    PubMed

    Simmelink, Elisabeth K; Borgesius, Emilie C; Hettinga, Florentina J; Geertzen, Jan H B; Dekker, Rienk; van der Woude, Lucas H V

    2015-03-01

    The combined arm-leg (Cruiser) ergometer is assumed to be a relevant testing and training instrument in the rehabilitation of patients with a lower limb amputation. The efficiency and submaximal strain have not been established and thus cannot be compared with alternative common modes of exercise. A total of 22 healthy able-bodied men (n=10) and women (n=12) were enrolled in four discontinuous submaximal graded exercise tests. Each test consisted of seven bouts of 3 min exercise ranging from 20 to 45 W and was performed on, respectively, the Cruiser ergometer, a bicycle ergometer, a handbike, and again the Cruiser ergometer. Cardiorespiratory parameters were measured and rate of perceived exertion was determined. Gross mechanical efficiency (GE) was determined from power output and submaximal steady-state energy cost. Repeated-measures analysis of variance (P<0.05) was used to evaluate the effects of exercise mode, exercise intensity, and sex. No differences in GE and cardiorespiratory strain were found between both Cruiser tests (GE 45 W: men 13.0%, women 15%) and the bicycle test (GE 45 W: men 13.2%, women 14.6%). GEs of handbiking (45 W: men 11.2%, women 12.2%) were lower compared with the Cruiser and bicycle test results, whereas cardiorespiratory strain in handbiking was consistently higher. Apart from a lower rate of perceived exertion at the second Cruiser test, no differences were found between the repeated Cruiser tests. It can be concluded that GE and cardiorespiratory strain in submaximal Cruiser exercise are comparable with leg cycling, the repeatability was good, and no obvious learning effects were observed. The results of this study form a base for further research in patients with a lower limb amputation.

  10. A novel testing platform for assessing knee joint mechanics: a parallel robotic system combined with an instrumented spatial linkage.

    PubMed

    Atarod, Mohammad; Rosvold, Joshua M; Frank, Cyril B; Shrive, Nigel G

    2014-05-01

    Assessing joint function following trauma and its inter-relation with degenerative changes requires an understanding of the normal state of structural loading in the joint. Very few studies have attempted to reproduce joint specific in vivo motions in vitro to quantify the actual loads carried by different tissues within the knee joint. The most significant challenge in this area is the very high sensitivity of the loads in joint structures to motion reproduction accuracy. A novel testing platform for assessing knee joint mechanics is described, comprised of a highly accurate (0.3 ± 0.1 mm, 0.3 ± 0.1°) six-degree-of-freedom (6-DOF) instrumented spatial linkage (ISL) for in vivo joint kinematic assessments and a unique 6-DOF parallel robotic manipulator. A position feedback system (ISL and position controller) is used for accurate reproduction of in vivo joint motions and estimation of "in situ" joint/tissue loads. The parallel robotic manipulator provides excellent stiffness and repeatability in reproducing physiological motions in 6-DOF, compared to the commonly used serial robots. The position feedback system provides real-time feedback data to the robot to reproduce in vivo motions and significantly enhances motion reproduction accuracy by adjusting for robot end-effector movements. Using this combined robot-ISL system, in vivo motions can be reproduced in vitro with very high accuracy (0.1 mm, 0.1°). Our results indicate that this level of accuracy is essential for meaningful estimation of tissue loads during gait. Using this novel testing platform, we have determined the normal load-carrying characteristics of different tissues within the ovine knee joint. The application of this testing system will continue to increase our understanding of normal and pathological joint states. PMID:24519725

  11. Experimental study of ultra-thin films mechanical integrity by combined nanoindentation and nano-acoustic emission

    NASA Astrophysics Data System (ADS)

    Zhang, Zihou

    Advancement of interconnect technology has imposed significant challenge on interface characterization and reliability for blurred interfaces between layers. There is a need for material properties and these miniaturized length scales and assessment of reliability; including the intrinsic film fracture toughness and the interfacial fracture toughness. The nano-meter range of film thicknesses currently employed, impose significant challenges on evaluating these physical quantities and thereby impose significant challenge on the design cycle. In this study we attempted to use a combined nano-indentation and nano-acoustic emission to qualitatively and quantitatively characterize the failure modes in ultra-thin blanket films on Si substrates or stakes of different characteristics. We have performed and analyzed an exhaustive group of testes that cove many diverge combination of film-substrate combination, provided by both Intel and IBM. When the force-indentation depth curve shows excursion, a direct measure of the total energy release rate is estimated. The collected acoustic emission signal is then used to partition the total energy into two segments, one associated with the cohesive fracture toughness of the film and the other is for the adhesive fracture toughness of the interface. The acoustic emission signal is analyzed in both the time and frequency domain to achieve such energy division. In particular, the signal time domain analysis for signal skewness, time of arrival and total energy content are employed with the proper signal to noise ratio. In the frequency domain, an expansive group of acoustic emission signals are utilized to construct the details of the power spectral density. A bank of band-pass filters are designed to sort the individual signals to those associated with adhesive interlayer cracking, cohesive channel cracking, or other system induced noise. The attenuation time and the energy content within each spectral frequency were the key elements

  12. Mechanism of action of chlorhexidine diacetate and phenoxyethanol singly and in combination against gram-negative bacteria.

    PubMed

    Fitzgerald, K A; Davies, A; Russell, A D

    1992-01-01

    Chlorhexidine diacetate and the aromatic alcohol, phenoxyethanol in combination had an enhanced bacteriostatic action against Escherichia coli and Pseudomonas aeruginosa strains. Investigations of potassium (K+) ion leakage by means of a potassium electrode and a radioactive method, employing 86Rb, indicated that the combination accelerated the rate of leakage from the cell. Leakage of pentose was also found to be enhanced in the presence of the combination compared with either drug alone.

  13. IM-133N - A Useful Herbal Combination for Eradicating Disease-triggering Pathogens in Mice via Immunotherapeutic Mechanisms

    PubMed Central

    Firashathulla, Syed; Inamdar, Mohammed Naseeruddin; Rafiq, Mohamed; Viswanatha, Gollapalle Lakshminarayanashastry; Sharath Kumar, Lakkavalli Mohan; Babu, Uddagiri Venkanna; Ramakrishnan, Shyam; Paramesh, Rangesh

    2016-01-01

    Objectives: The present study was undertaken to evaluate the immunomodulatory (IM) activity of IM-133N, a herbal combination in various immunotherapeutic experimental models. Methods: The IM activity of IM-133N was evaluated against three experimental models namely, effect of IM- 133N against Escherichia coli (E. coli)-induced abdominal sepsis in mice, and carbon clearance test was performed in Wistar albino rats to evaluated the phagocytic potential of IM-133N, in addition IM-133N was evaluated for its immunoglobulin enhancing potential in rats, where the immunoglobulin levels were measured by zinc sulphate turbity (ZST) test. Further, IM-133N was subjected for detailed liquid chromatography-mass spectrometry (LC-MS)/MS analysis to identify the probable active constituents present in it. Results: The findings of the present study has demonstrated very promising IM property of IM-133N in all the experimental models. Briefly, pretreatment with IM-133N at 125, 250, 500 and 1,000 mg/kg, p.o. doses had protected the mice against E. coli-induced abdominal sepsis and mortality, further the effect of IM- 133N was found to be significant and dose-dependent. In support of this, in another study administration of IM-133N showed a significant and dose-dependent increase in serum immunoglobulin levels, estimated by ZST test. In line with the above findings, in the carbon clearance test the low doses (125 and 250 mg/ kg, p.o.) of IM-133N increased the rate of carbon clearance, whereas the higher doses (500 and 1,000 mg/kg, p.o.) did not sustain the response, and saturation effect was considered as one of the possible reason for futility of higher doses for IM-133N. In addition, A detailed LC-MS/MS analysis of IM-133N showed 17 bioactive phytochemical constituents: namely, apigenin, chaulmoogric acid, mesquitol, quercetin, symphoxanthone, salireposide, β-sitosterol, nonaeicosanol, β-amyrin, betulic acid, oleanolic acid, symplososide, symponoside, symploveroside, symplocomoside

  14. Multi-drug resistance transporters and a mechanism-based strategy for assessing risks of pesticide combinations to honey bees

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Annual losses of honey bee colonies remain high and pesticide exposure is one possible cause. Dangerous combinations of pesticides, plant-produced compounds and antibiotics added to hives may cause or contribute to losses, but it is very difficult to test the many combinations of those compounds tha...

  15. Increased proliferation and differentiation of pre-osteoblasts MC3T3-E1 cells on nanostructured polypyrrole membrane under combined electrical and mechanical stimulation.

    PubMed

    Liu, Lizhen; Li, Ping; Zhou, Gang; Wang, Menghang; Jia, Xiaoling; Liu, Meili; Niu, Xufeng; Song, Wei; Liu, Haifeng; Fan, Yubo

    2013-09-01

    Polypyrrole (PPy), as an electrical conductive polymer, has been widely investigated in biomedical fields. In this study, PPy membrane at nanoscale was electrically deposited on indium-tin oxide glass slide with sodium p-toluenesulfonate as supporting electrolyte. Electropolymerization of PPy was performed under a constant 800 mV voltage for 10 seconds. Chemical compositions and morphology were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results showed that the nanoscaled PPy particles distributed uniformly and the average diameter of PPy particles was 62 nm. Since bone cells can respond to both electrical and mechanical stimulation in vivo, pre-osteoblasts MC3T3-E1 cells were cultured ort nanostructured PPy membrane under the combined electrical and mechanical stimulation. The nano-PPy membrane was conducive to transferring uniform electrical stimulation and applying steady mechanical stimulation. It is suggested that the combined stimulation did not affect cells morphologies significantly. However, cell proliferation tested by MTT, alkaline phosphatase activities, and gene expression of Collagen-I indicated that combined stimulation can enhance the proliferation and differentiation of MC3T3-E1 cells more efficiently than single electrical stimulation or single mechanical stimulation. The combined stimulation through a nano-PPy membrane may provide a highly potential stimulated method in bone tissue engineering.

  16. Mechanical Removal of Migrated Onyx Due to Microcatheter Rupture During AVM Embolization: A Technical Case Report.

    PubMed

    Senturk, Cagin

    2015-12-01

    We report a case where migrated Onyx could be removed safely with a mechanical thrombectomy device after withdrawal of the damaged microcatheter. A microcatheter was retained in the superior cerebellar artery with attached Onyx fragments on its tip during embolization of a bled cerebellar AVM. During retrieval maneuvers microcatheter shaft was ruptured and Onyx fragments were released into the vertebrobasilar system causing occlusion. Finally, Onyx fragment on tip of the microcatheter could be detached with dimethyl sulfoxide injection and the microcatheter could be withdrawn. A Merci retriever device (Concentric Medical, Mountain View, CA, USA) was successfully used to retrieve most of the dislodged Onyx material and recanalize the vertebrobasilar circulation.

  17. Use of Percutaneous Aspiration Thrombectomy vs. Anticoagulation Therapy to Treat Acute Iliofemoral Venous Thrombosis: 1-year Follow-up Results of a Randomised, Clinical Trial

    SciTech Connect

    Cakir, Volkan; Gulcu, Aytac; Akay, Emrah; Capar, Ahmet E.; Gencpinar, Tugra; Kucuk, Banu; Karabay, Ozalp; Goktay, A. Yigit

    2014-08-15

    PurposeThe purpose of this study was to compare the efficacy of percutaneous aspiration thrombectomy (PAT) followed by standard anticoagulant therapy, with anticoagulation therapy alone, for the treatment of acute proximal lower extremity deep vein thrombosis.MethodsIn this randomised, prospective study, 42 patients with acute proximal iliofemoral deep vein thrombosis documented via Doppler ultrasound examination, were separated into an interventional treatment group (16 males, 5 females, average age 51 years) and a medical treatment group (13 males, 8 females, average age 59 years). In the interventional group, PAT with large-lumen 9-F diameter catheterisation was applied, after initiation of standard anticoagulant therapy. Balloon angioplasty (n 19) and stent implementation (n: 14) were used to treat patients with residual stenosis (>50 %) after PAT. Prophylactic IVC filters were placed in two patients. The thrombus clearance status of the venous system was evaluated by venography. In both the medical and interventional groups, venous patency rates and clinical symptom scores were evaluated at months 1, 3, and 12 after treatment.ResultsDeep venous systems became totally cleared of thrombi in 12 patients treated with PAT. The venous patency rates in month 12 were 57.1 and 4.76 % in the interventional and medical treatment groups, respectively. A statistically significant improvement was observed in clinical symptom scores of the interventional group (PAT) with or without stenting (4.23 ± 0.51 before treatment; 0.81 ± 0.92 at month 12) compared with the medical treatment group (4.00 ± 0.63 before treatment; 2.43 ± 0.67 at month 12). During follow-up, four patients in the medical treatment and one in the interventional group developed pulmonary embolisms.ConclusionsFor treatment of acute deep vein thrombosis, PAT with or without stenting is superior to anticoagulant therapy alone in terms of both ensuring venous patency and improving clinical

  18. Structure of Low-Lying Excited States of Guanine in DNA and Solution: Combined Molecular Mechanics and High-Level Coupled Cluster Studies

    DOE PAGES

    Kowalski, Karol; Valiev, Marat

    2007-01-01

    High-level ab-initio equation-of-motion coupled-cluster methods with singles, doubles, and noniterative triples are used, in conjunction with the combined quantum mechanical molecular mechanics approach, to investigate the structure of low-lying excited states of the guanine base in DNA and solvated environments. Our results indicate that while the excitation energy of the first excited state is barely changed compared to its gas-phase counterpart, the excitation energy of the second excited state is blue-shifted by 0.24 eV.

  19. Overall non-linear correction of phase shifting mechanism in white light interferometry system based on displacement feedback control combined with fuzzy PID control

    NASA Astrophysics Data System (ADS)

    Song, Ningfang; Luo, Xinkai; Li, Huipeng; Li, Jiao

    2015-10-01

    The non-linearity of the phase shifting mechanism in white light interferometry system can seriously affect the measuring accuracy of the system. In this paper, the correcting method is to combine the displacement feedback control technology with the fuzzy PID control technology. Displacement feedback control mechanism and fuzzy PID controller are designed and then try to figure it out through Matlab simulation and experiment.. The result shows that combining the displacement feedback control technology with the fuzzy PID control technology can fulfill decent overall non-linear correction in the white light interferometry measuring system. Meanwhile, the accuracy of the correction is high and the non-linearity drop from 2% to 0.1%.

  20. Damage Detection Based on Power Dissipation Measured with PZT Sensors through the Combination of Electro-Mechanical Impedances and Guided Waves

    PubMed Central

    Sevillano, Enrique; Sun, Rui; Perera, Ricardo

    2016-01-01

    The use of piezoelectric ceramic transducers (such as Lead-Zirconate-Titanate—PZT) has become more and more widespread for Structural Health Monitoring (SHM) applications. Among all the techniques that are based on this smart sensing solution, guided waves and electro-mechanical impedance techniques have found wider acceptance, and so more studies and experimental works can be found containing these applications. However, even though these two techniques can be considered as complementary to each other, little work can be found focused on the combination of them in order to define a new and integrated damage detection procedure. In this work, this combination of techniques has been studied by proposing a new integrated damage indicator based on Electro-Mechanical Power Dissipation (EMPD). The applicability of this proposed technique has been tested through different experimental tests, with both lab-scale and real-scale structures. PMID:27164104

  1. Damage Detection Based on Power Dissipation Measured with PZT Sensors through the Combination of Electro-Mechanical Impedances and Guided Waves.

    PubMed

    Sevillano, Enrique; Sun, Rui; Perera, Ricardo

    2016-01-01

    The use of piezoelectric ceramic transducers (such as Lead-Zirconate-Titanate-PZT) has become more and more widespread for Structural Health Monitoring (SHM) applications. Among all the techniques that are based on this smart sensing solution, guided waves and electro-mechanical impedance techniques have found wider acceptance, and so more studies and experimental works can be found containing these applications. However, even though these two techniques can be considered as complementary to each other, little work can be found focused on the combination of them in order to define a new and integrated damage detection procedure. In this work, this combination of techniques has been studied by proposing a new integrated damage indicator based on Electro-Mechanical Power Dissipation (EMPD). The applicability of this proposed technique has been tested through different experimental tests, with both lab-scale and real-scale structures. PMID:27164104

  2. Biomechanical aspects of segmented arch mechanics combined with power arm for controlled anterior tooth movement: A three-dimensional finite element study

    PubMed Central

    Ozaki, Hiroya; Tominaga, Jun-ya; Hamanaka, Ryo; Sumi, Mayumi; Chiang, Pao-Chang; Tanaka, Motohiro; Koga, Yoshiyuki

    2015-01-01

    The porpose of this study was to determine the optimal length of power arms for achieving controlled anterior tooth movement in segmented arch mechanics combined with power arm. A three-dimensional finite element method was applied for the simulation of en masse anterior tooth retraction in segmented power arm mechanics. The type of tooth movement, namely, the location of center of rotation of the maxillary central incisor in association with power arm length, was calculated after the retraction force was applied. When a 0.017 × 0.022-in archwire was inserted into the 0.018-in slot bracket, bodily movement was obtained at 9.1 mm length of power arm, namely, at the level of 1.8 mm above the center of resistance. In case a 0.018 × 0.025-in full-size archwire was used, bodily movement of the tooth was produced at the power arm length of 7.0 mm, namely, at the level of 0.3 mm below the center of resistance. Segmented arch mechanics required shorter length of power arms for achieving any type of controlled anterior tooth movement as compared to sliding mechanics. Therefore, this space closing mechanics could be widely applied even for the patients whose gingivobuccal fold is shallow. The segmented arch mechanics combined with power arm could provide higher amount of moment-to-force ratio sufficient for controlled anterior tooth movement without generating friction, and vertical forces when applying retraction force parallel to the occlusal plane. It is, therefore, considered that the segmented power arm mechanics has a simple appliance design and allows more efficient and controllable tooth movement. PMID:25610497

  3. Biomechanical aspects of segmented arch mechanics combined with power arm for controlled anterior tooth movement: A three-dimensional finite element study.

    PubMed

    Ozaki, Hiroya; Tominaga, Jun-Ya; Hamanaka, Ryo; Sumi, Mayumi; Chiang, Pao-Chang; Tanaka, Motohiro; Koga, Yoshiyuki; Yoshida, Noriaki

    2015-01-01

    The porpose of this study was to determine the optimal length of power arms for achieving controlled anterior tooth movement in segmented arch mechanics combined with power arm. A three-dimensional finite element method was applied for the simulation of en masse anterior tooth retraction in segmented power arm mechanics. The type of tooth movement, namely, the location of center of rotation of the maxillary central incisor in association with power arm length, was calculated after the retraction force was applied. When a 0.017 × 0.022-in archwire was inserted into the 0.018-in slot bracket, bodily movement was obtained at 9.1 mm length of power arm, namely, at the level of 1.8 mm above the center of resistance. In case a 0.018 × 0.025-in full-size archwire was used, bodily movement of the tooth was produced at the power arm length of 7.0 mm, namely, at the level of 0.3 mm below the center of resistance. Segmented arch mechanics required shorter length of power arms for achieving any type of controlled anterior tooth movement as compared to sliding mechanics. Therefore, this space closing mechanics could be widely applied even for the patients whose gingivobuccal fold is shallow. The segmented arch mechanics combined with power arm could provide higher amount of moment-to-force ratio sufficient for controlled anterior tooth movement without generating friction, and vertical forces when applying retraction force parallel to the occlusal plane. It is, therefore, considered that the segmented power arm mechanics has a simple appliance design and allows more efficient and controllable tooth movement.

  4. Rational combination of targeted therapies as a strategy to overcome the mechanisms of resistance to inhibitors of EGFR signaling.

    PubMed

    Bianco, Roberto; Damiano, Vincenzo; Gelardi, Teresa; Daniele, Gennaro; Ciardiello, Fortunato; Tortora, Giampaolo

    2007-01-01

    The epidermal growth factor receptor (EGFR) has been widely used as a target for novel anticancer agents, such as blocking antibodies and small molecular weight tyrosine kinase compounds. In spite of recent advances in cancer cell biology, leading to the introduction of clinically active new drugs, such as cetuximab, panitumumab and erlotinib, unfortunately disease control remains unsuccessful due to the presence of constitutive resistance to EGFR inhibitors in most patients and the development of acquired resistance in the responders. A large number of molecular abnormalities in tumor cells seem to partly contribute to their resistance to anti-EGFR therapy: increased angiogenesis, constitutive activation of downstream mediators, overexpression of other tyrosine kinase receptors. Moreover, some mutations in the EGFR receptor kinase domain seem to play a crucial role in determining the sensitivity of cancer cells to specific inhibitors by altering the conformation of the receptor and its activity. The development of rational combinations of anticancer agents and EGFR inhibitors, able to exert synergistic cytotoxic interactions, has been widely accepted and used in both preclinical and clinical studies. Although the failure of large clinical trial based on empirical combination of anti-EGFR and classic chemotherapeutic agents, several preclinical data seems to support the hypothesis that combining EGFR inhibitors and other novel agents could efficiently inhibit tumor growth and overcome intrinsic resistance to a single-agent based therapy. This review focuses on the role of complementary signalling pathways in the development of resistance to EGFR targeting agents and the rationale to combine novel inhibitors as anticancer therapy.

  5. Elimination of HCV via a non-ISG-mediated mechanism by vaniprevir and BMS-788329 combination therapy in human hepatocyte chimeric mice.

    PubMed

    Uchida, Takuro; Hiraga, Nobuhiko; Imamura, Michio; Yoshimi, Satoshi; Kan, Hiromi; Miyaki, Eisuke; Tsuge, Masataka; Abe, Hiromi; Hayes, C Nelson; Aikata, Hiroshi; Ishida, Yuji; Tateno, Chise; Ellis, Joan D; Chayama, Kazuaki

    2016-02-01

    We previously reported that interferon (IFN)-free direct-acting antiviral combination treatment succeeded in eradicating genotype 1b hepatitis C virus (HCV) in human hepatocyte chimeric mice. In this study, we examined the effect of vaniprevir (MK7009, NS3/4A protease inhibitor) and BMS-788329 (NS5A inhibitor) combination treatment on HCV genotype 1b and the expression of IFN-stimulated genes (ISGs) using a subgenomic replicon system and the same animal model. Combination treatment with vaniprevir and BMS-788329 significantly reduced HCV replication compared to vaniprevir monotherapy in HCV replicon cells (Huh7/Rep-Feo cells). HCV genotype 1b-infected human hepatocyte chimeric mice were treated with vaniprevir alone or in combination with BMS-788329 for four weeks. Vaniprevir monotherapy reduced serum HCV RNA titers in mice, but viral breakthrough was observed in mice with high HCV titers. Ultra-deep sequence analysis revealed a predominant replacement by drug-resistant substitutions at 168 in HCV NS3 region in these mice. Conversely, in mice with low HCV titers, HCV was eradicated by vaniprevir monotherapy without viral breakthrough. In contrast to monotherapy, combination treatment with vaniprevir and BMS-788329 succeeded in completely eradicating HCV regardless of serum viral titer. IFN-alpha treatment significantly increased ISG expression; however, vaniprevir and BMS-788329 combination treatment caused no increase in ISG expression both in cultured cells and in mouse livers. Therefore, combination treatment with vaniprevir and BMS-788329 eliminated HCV via a non-ISG-mediated mechanism. This oral treatment might offer an alternative DAA combination therapy for patients with chronic hepatitis C. PMID:26569595

  6. A new water absorbable mechanical Epidermal skin equivalent: the combination of hydrophobic PDMS and hydrophilic PVA hydrogel.

    PubMed

    Morales-Hurtado, M; Zeng, X; Gonzalez-Rodriguez, P; Ten Elshof, J E; van der Heide, E

    2015-06-01

    Research on human skin interactions with healthcare and lifestyle products is a topic continuously attracting scientific studies over the past years. It is possible to evaluate skin mechanical properties based on human or animal experimentation, yet in addition to possible ethical issues, these samples are hard to obtain, expensive and give rise to highly variable results. Therefore, the design of a skin equivalent is essential. This paper describes the design and characterization of a new Epidermal Skin Equivalent (ESE). The material resembles the properties of epidermis and is a first approach to mimic the mechanical properties of the human skin structure, variable with the length scale. The ESE is based on a mixture of Polydimethyl Siloxane (PDMS) and Polyvinyl Alcohol (PVA) hydrogel cross-linked with Glutaraldehyde (GA). It was chemically characterized by XPS and FTIR measurements and its cross section was observed by macroscopy and cryoSEM. Confocal Microscope analysis on the surface of the ESE showed an arithmetic roughness (Ra) between 14-16 μm and contact angle (CA) values between 50-60°, both of which are close to the values of in vivo human skins reported in the literature. The Equilibrium Water Content (ECW) was around 33.8% and Thermo Gravimetric Analysis (TGA) confirmed the composition of the ESE samples. Moreover, the mechanical performance was determined by indentation tests and Dynamo Thermo Mechanical Analysis (DTMA) shear measurements. The indentation results were in good agreement with that of the target epidermis reported in the literature with an elastic modulus between 0.1-1.5 MPa and it showed dependency on the water content. According to the DTMA measurements, the ESE exhibits a viscoelastic behavior, with a shear modulus between 1-2.5MPa variable with temperature, frequency and the hydration of the samples.

  7. [Incontinence after radical prostatectomy and cystectomy: are combined training with mechanical devices and whole body vibration effective?].

    PubMed

    Zellner, M

    2011-04-01

    In spite of improvements in nerve-sparing operation techniques in radical prostatectomies, a disturbance of (early) continence is subjectively perceived by a number of patients as burdensome, which can last for several months. Skilled physiotherapy is appreciated as causal therapy in the hands of the qualified therapist. In an open randomised controlled trial the efficacy of a standardised rehabilitation therapy with pelvic floor re-education instructed by a physiotherapist (n=25) as the control group in comparison to a group with additional combined electrostimulation and biofeedback device (Myo 420™; n=25) or whole body vibration therapy (FitVibe medical™; n=25). Pre- and post-therapeutic evaluation of the International Prostate Symptom Score (IPSS), the enclosed question about quality of life (IPSS-QL), pad test, pelvic floor strength, maximum uroflow, micturition volume, serum testosterone and blood glucose was done. Within the treatment duration of 3-4 weeks in all treatment groups a statistically significant improvement of IPSS and IPSS-QL was seen. Due to whole body vibration the reduction of urine loss (pad test), increase of voided volume and maximum uroflow were statistically significant. Whereas for isolated physiotherapy during the short therapy duration merely a trend for the improvement of pelvic floor muscle strength was seen, the difference was significant in the Myo 420 and the whole body vibration groups, respectively. It was shown that a continuous improvement in continence depends on the consistent continuation of the training also under domestic conditions. The controlled trial conditions also confirm the efficacy, acceptance and tolerance of a standardised pelvic floor re-education under the conditions of urological inpatient rehabilitation treatment. By additional use of a combined electro- and multichannel biofeedback device or a whole body vibration device, the treatment results could be further improved. Due to the different causal

  8. [Incontinence after radical prostatectomy and cystectomy: are combined training with mechanical devices and whole body vibration effective?].

    PubMed

    Zellner, M

    2011-04-01

    In spite of improvements in nerve-sparing operation techniques in radical prostatectomies, a disturbance of (early) continence is subjectively perceived by a number of patients as burdensome, which can last for several months. Skilled physiotherapy is appreciated as causal therapy in the hands of the qualified therapist. In an open randomised controlled trial the efficacy of a standardised rehabilitation therapy with pelvic floor re-education instructed by a physiotherapist (n=25) as the control group in comparison to a group with additional combined electrostimulation and biofeedback device (Myo 420™; n=25) or whole body vibration therapy (FitVibe medical™; n=25). Pre- and post-therapeutic evaluation of the International Prostate Symptom Score (IPSS), the enclosed question about quality of life (IPSS-QL), pad test, pelvic floor strength, maximum uroflow, micturition volume, serum testosterone and blood glucose was done. Within the treatment duration of 3-4 weeks in all treatment groups a statistically significant improvement of IPSS and IPSS-QL was seen. Due to whole body vibration the reduction of urine loss (pad test), increase of voided volume and maximum uroflow were statistically significant. Whereas for isolated physiotherapy during the short therapy duration merely a trend for the improvement of pelvic floor muscle strength was seen, the difference was significant in the Myo 420 and the whole body vibration groups, respectively. It was shown that a continuous improvement in continence depends on the consistent continuation of the training also under domestic conditions. The controlled trial conditions also confirm the efficacy, acceptance and tolerance of a standardised pelvic floor re-education under the conditions of urological inpatient rehabilitation treatment. By additional use of a combined electro- and multichannel biofeedback device or a whole body vibration device, the treatment results could be further improved. Due to the different causal

  9. A New Animal Model for Investigation of Mechanical Unloading in Hypertrophic and Failing Hearts: Combination of Transverse Aortic Constriction and Heterotopic Heart Transplantation

    PubMed Central

    Stenzig, Justus; Biermann, Daniel; Jelinek, Marisa; Reichenspurner, Hermann; Eschenhagen, Thomas; Ehmke, Heimo; Schwoerer, Alexander P.

    2016-01-01

    Objectives Previous small animal models for simulation of mechanical unloading are solely performed in healthy or infarcted hearts, not representing the pathophysiology of hypertrophic and dilated hearts emerging in heart failure patients. In this article, we present a new and economic small animal model to investigate mechanical unloading in hypertrophic and failing hearts: the combination of transverse aortic constriction (TAC) and heterotopic heart transplantation (hHTx) in rats. Methods To induce cardiac hypertrophy and failure in rat hearts, three-week old rats underwent TAC procedure. Three and six weeks after TAC, hHTx with hypertrophic and failing hearts in Lewis rats was performed to induce mechanical unloading. After 14 days of mechanical unloading animals were euthanatized and grafts were explanted for further investigations. Results 50 TAC procedures were performed with a survival of 92% (46/50). When compared to healthy rats left ventricular surface decreased to 5.8±1.0 mm² (vs. 9.6± 2.4 mm²) (p = 0.001) after three weeks with a fractional shortening (FS) of 23.7± 4.3% vs. 28.2± 1.5% (p = 0.01). Six weeks later, systolic function decreased to 17.1± 3.2% vs. 28.2± 1.5% (p = 0.0001) and left ventricular inner surface increased to 19.9±1.1 mm² (p = 0.0001). Intraoperative graft survival during hHTx was 80% with 46 performed procedures (37/46). All transplanted organs survived two weeks of mechanical unloading. Discussion Combination of TAC and hHTx in rats offers an economic and reproducible small animal model enabling serial examination of mechanical unloading in a truly hypertrophic and failing heart, representing the typical pressure overloaded and dilated LV, occurring in patients with moderate to severe heart failure. PMID:26841021

  10. [Mechanisms for the increased fertilizer nitrogen use efficiency of rice in wheat-rice rotation system under combined application of inorganic and organic fertilizers].

    PubMed

    Liu, Yi-Ren; Li, Xiang; Yu, Jie; Shen, Qi-Rong; Xu, Yang-Chun

    2012-01-01

    A pot experiment was conducted to study the effects of combined application of organic and inorganic fertilizers on the nitrogen uptake by rice and the nitrogen supply by soil in a wheat-rice rotation system, and approach the mechanisms for the increased fertilizer nitrogen use efficiency of rice under the combined fertilization from the viewpoint of microbiology. Comparing with applying inorganic fertilizers, combined application of organic and inorganic fertilizers decreased the soil microbial biomass carbon and nitrogen and soil mineral nitrogen contents before tillering stage, but increased them significantly from heading to filling stage. Under the combined fertilization, the dynamics of soil nitrogen supply matched best the dynamics of rice nitrogen uptake and utilization, which promoted the nitrogen accumulation in rice plant and the increase of rice yield and biomass, and increased the fertilizer nitrogen use efficiency of rice significantly. Combined application of inorganic and organic fertilizers also promoted the propagation of soil microbes, and consequently, more mineral nitrogen in soil was immobilized by the microbes at rice early growth stage, and the immobilized nitrogen was gradually released at the mid and late growth stages of rice, being able to better satisfy the nitrogen demand of rice in its various growth and development stages. PMID:22489483

  11. [Mechanisms for the increased fertilizer nitrogen use efficiency of rice in wheat-rice rotation system under combined application of inorganic and organic fertilizers].

    PubMed

    Liu, Yi-Ren; Li, Xiang; Yu, Jie; Shen, Qi-Rong; Xu, Yang-Chun

    2012-01-01

    A pot experiment was conducted to study the effects of combined application of organic and inorganic fertilizers on the nitrogen uptake by rice and the nitrogen supply by soil in a wheat-rice rotation system, and approach the mechanisms for the increased fertilizer nitrogen use efficiency of rice under the combined fertilization from the viewpoint of microbiology. Comparing with applying inorganic fertilizers, combined application of organic and inorganic fertilizers decreased the soil microbial biomass carbon and nitrogen and soil mineral nitrogen contents before tillering stage, but increased them significantly from heading to filling stage. Under the combined fertilization, the dynamics of soil nitrogen supply matched best the dynamics of rice nitrogen uptake and utilization, which promoted the nitrogen accumulation in rice plant and the increase of rice yield and biomass, and increased the fertilizer nitrogen use efficiency of rice significantly. Combined application of inorganic and organic fertilizers also promoted the propagation of soil microbes, and consequently, more mineral nitrogen in soil was immobilized by the microbes at rice early growth stage, and the immobilized nitrogen was gradually released at the mid and late growth stages of rice, being able to better satisfy the nitrogen demand of rice in its various growth and development stages.

  12. Rice and Bean Targets for Biofortification Combined with High Carotenoid Content Crops Regulate Transcriptional Mechanisms Increasing Iron Bioavailability.

    PubMed

    Dias, Desirrê Morais; de Castro Moreira, Maria Eliza; Gomes, Mariana Juste Contin; Lopes Toledo, Renata Celi; Nutti, Marilia Regini; Pinheiro Sant'Ana, Helena Maria; Martino, Hércia Stampini Duarte

    2015-11-01

    Iron deficiency affects thousands of people worldwide. Biofortification of staple food crops aims to support the reduction of this deficiency. This study evaluates the effect of combinations of common beans and rice, targets for biofortification, with high carotenoid content crops on the iron bioavailability, protein gene expression, and antioxidant effect. Iron bioavailability was measured by the depletion/repletion method. Seven groups were tested (n = 7): Pontal bean (PB); rice + Pontal bean (R + BP); Pontal bean + sweet potato (PB + SP); Pontal bean + pumpkin (PB + P); Pontal bean + rice + sweet potato (PB + R + P); Pontal bean + rice + sweet potato (PB + R + SP); positive control (Ferrous Sulfate). The evaluations included: hemoglobin gain, hemoglobin regeneration efficiency (HRE), gene expression of divalente metal transporter 1 (DMT-1), duodenal citocromo B (DcytB), ferroportin, hephaestin, transferrin and ferritin and total plasma antioxidant capacity (TAC). The test groups, except the PB, showed higher HRE (p < 0.05) than the control. Gene expression of DMT-1, DcytB and ferroportin increased (p < 0.05) in the groups fed with high content carotenoid crops (sweet potato or pumpkin). The PB group presented lower (p < 0.05) TAC than the other groups. The combination of rice and common beans, and those with high carotenoid content crops increased protein gene expression, increasing the iron bioavailability and antioxidant capacity.

  13. Erosion mechanisms in combined sewers and the potential for pollutant release to receiving waters and water treatment plants.

    PubMed

    McIlhatton, T D; Sakrabani, R; Ashle, R M; Burrows, R

    2002-01-01

    The problems associated with solids in sewerage systems result in common difficulties such as blockages and flooding and the subsequent maintenance requirements have been well documented. Concerns regarding pollutant release have also been demonstrated, with the contribution from in-sewer solids to the quality of the flow during a storm event being especially significant. These events known as "foul flushes" in combined sewers typically occur in the initial period of storm flows, when the concentration of suspended sediments and other pollutants are significantly higher than at other times. Traditionally impacts from these events have been related to the suspended solids phase of the flow passing through a CSO structure. It is now apparent that much of the suspended load originates from solids eroded from the bed. The "near bed solids" which are re-entrained into the flow, together with solids eroded from the bulk bed, account for large changes in the suspended sediment concentration under time varying flow conditions. The influence of these eroded solids and their potential impact on receiving waters and treatment plants will be reviewed using data obtained from field studies carried out in the main Dundee interceptor sewer in Scotland. This paper describes some of the methods employed to investigate the characteristics of the pollutants associated with solids erosion in combined sewers.

  14. Cathepsin S attenuates endosomal EGFR signalling: A mechanical rationale for the combination of cathepsin S and EGFR tyrosine kinase inhibitors

    PubMed Central

    Huang, Chien-Chang; Lee, Cheng-Che; Lin, Hsiao-Han; Chang, Jang-Yang

    2016-01-01

    EGF-mediated EGFR endocytosis plays a crucial role in the attenuation of EGFR activation by sorting from early endosomes to late endosomes and transporting them into lysosomes for the final proteolytic degradation. We previously observed that cathepsin S (CTSS) inhibition induces tumour cell autophagy through the EGFR-mediated signalling pathway. In this study, we further clarified the relationship between CTSS activities and EGFR signalling regulation. Our results revealed that CTSS can regulate EGFR signalling by facilitating EGF-mediated EGFR degradation. CTSS inhibition delayed the EGFR degradation process and caused EGFR accumulation in the late endosomes at the perinuclear region, which provides spatial compartments for prolonged EGFR and sustained downstream signal transducer and activator of transcription 3 and AKT signalling. Notably, cellular apoptosis was markedly enhanced by combining treatment with the EGFR inhibitor Iressa and CTSS inhibitor 6r. The data not only reveal a biological role of CTSS in EGFR signalling regulation but also evidence a rationale for its clinical evaluation in the combination of CTSS and EGFR tyrosine kinase inhibitors. PMID:27387133

  15. Drag and heat reduction mechanism induced by a combinational novel cavity and counterflowing jet concept in hypersonic flows

    NASA Astrophysics Data System (ADS)

    Sun, Xi-wan; Guo, Zhen-yun; Huang, Wei; Li, Shi-bin; Yan, Li

    2016-09-01

    The drag and heat reduction problem of hypersonic reentry vehicles has always attracted the attention worldwide, and many novel schemes have been proposed recently. In the current study, the research progress of the combinational configuration of the forward-facing cavity and the counterflowing jet has been reviewed, and the conventional cavity configuration has been substituted by an approximate maximum thrust nozzle contour for better heat and surface pressure reduction efficiency. The Reynolds-average of Navier-Stokes (RANS) equations coupled with the SST k-ω turbulence model have been employed to calculate its surrounding flow fields. A validation metric and the grid convergence index (GCI) have been employed to conduct the turbulence model assessment and the grid independence analysis respectively. The axisymmetric assumption has been verified by three-dimensional computational results as well. The obtained results show that the SST k-ω model is more suitable for the novel drag and heat flux reduction scheme proposed in this article, and the axisymmetric assumption is approximately reasonable. After investigating the influence of jet pressure ratio, the novel combinational configuration has been verified to be more effective in heat and surface pressure reduction, and this is because the approximate maximum thrust nozzle contour contributes to better expansion and avoids total pressure loss of the jet.

  16. Rice and Bean Targets for Biofortification Combined with High Carotenoid Content Crops Regulate Transcriptional Mechanisms Increasing Iron Bioavailability

    PubMed Central

    Dias, Desirrê Morais; de Castro Moreira, Maria Eliza; Gomes, Mariana Juste Contin; Lopes Toledo, Renata Celi; Nutti, Marilia Regini; Pinheiro Sant’Ana, Helena Maria; Martino, Hércia Stampini Duarte

    2015-01-01

    Iron deficiency affects thousands of people worldwide. Biofortification of staple food crops aims to support the reduction of this deficiency. This study evaluates the effect of combinations of common beans and rice, targets for biofortification, with high carotenoid content crops on the iron bioavailability, protein gene expression, and antioxidant effect. Iron bioavailability was measured by the depletion/repletion method. Seven groups were tested (n = 7): Pontal bean (PB); rice + Pontal bean (R + BP); Pontal bean + sweet potato (PB + SP); Pontal bean + pumpkin (PB + P); Pontal bean + rice + sweet potato (PB + R + P); Pontal bean + rice + sweet potato (PB + R + SP); positive control (Ferrous Sulfate). The evaluations included: hemoglobin gain, hemoglobin regeneration efficiency (HRE), gene expression of divalente metal transporter 1 (DMT-1), duodenal citocromo B (DcytB), ferroportin, hephaestin, transferrin and ferritin and total plasma antioxidant capacity (TAC). The test groups, except the PB, showed higher HRE (p < 0.05) than the control. Gene expression of DMT-1, DcytB and ferroportin increased (p < 0.05) in the groups fed with high content carotenoid crops (sweet potato or pumpkin). The PB group presented lower (p < 0.05) TAC than the other groups. The combination of rice and common beans, and those with high carotenoid content crops increased protein gene expression, increasing the iron bioavailability and antioxidant capacity. PMID:26610564

  17. Combined quantum mechanics and molecular mechanics simulation of Ca2+/ammonia solution based on the ONIOM-XS method: Octahedral coordination and implication to biology

    NASA Astrophysics Data System (ADS)

    Kerdcharoen, Teerakiat; Morokuma, Keiji

    2003-05-01

    An extension of the ONIOM (Own N-layered Integrated molecular Orbital and molecular Mechanics) method [M. Svensson, S. Humbel, R. D. J. Froese, T. Mutsubara, S. Sieber, and K. Morokuma, J. Phys. Chem. 100, 19357 (1996)] for simulation in the condensed phase, called ONIOM-XS (XS=eXtension to Solvation) [T. Kerdcharoen and K. Morokuma, Chem. Phys. Lett. 355, 257 (2002)], was applied to investigate the coordination of Ca2+ in liquid ammonia. A coordination number of 6 is found. Previous simulations based on pair potential or pair potential plus three-body correction gave values of 9 and 8.2, respectively. The new value is the same as the coordination number most frequently listed in the Cambridge Structural Database (CSD) and Protein Data Bank (PDB). N-Ca-N angular distribution reveals a near-octahedral coordination structure. Inclusion of many-body interactions (which amounts to 25% of the pair interactions) into the potential energy surface is essential for obtaining reasonable coordination number. Analyses of the metal coordination in water, water-ammonia mixture, and in proteins reveals that cation/ammonia solution can be used to approximate the coordination environment in proteins.

  18. Generation of mesenchymal stem cell from human umbilical cord tissue using a combination enzymatic and mechanical disassociation method.

    PubMed

    Tong, Chih Kong; Vellasamy, Shalini; Tan, Boon Chong; Abdullah, Maha; Vidyadaran, Sharmili; Seow, Heng Fong; Ramasamy, Rajesh

    2011-03-01

    MSCs (mesenchymal stem cells) promise a great potential for regenerative medicine due to their unique properties of self-renewal, high plasticity, modulation of immune response and the flexibility for genetic modification. Therefore, the increasing demand for cellular therapy necessitates a larger-scale production of MSC; however, the technical and ethical issues had put a halt on it. To date, studies have shown that MSC could be derived from human UC (umbilical cord), which is once considered as clinical waste. We have compared the two conventional methods which are classic enzymatic digestion and explant method with our newly tailored enzymatic-mechanical disassociation method to generate UC-MSC. The generated UC-MSCs from the methods above were characterized based on their immunophenotyping, early embryonic transcription factors expression and mesodermal differentiation ability. Our results show that enzymatic-mechanical disassociation method increase the initial nucleated cell yield greatly (approximately 160-fold) and maximized the successful rate of UC-MSC generation. Enzymatic-mechanical disassociation-derived UC-MSC exhibited fibroblastic morphology and surface markers expression of CD105, CD73, CD29, CD90 and MHC class I. Furthermore, these cells constitutively express early embryonic transcription factors (Nanog, Oct-4, Sox-2 and Rex-1), as confirmed by RT-PCR, indicating their multipotency and high self-renewal capacity. They are also capable of differentiating into osteoblasts and adipocytes when given an appropriate induction. The present study demonstrates a new and efficient approach in generating MSC from UC, hence serving as ideal alternative source of mesenchymal stem cell for clinical and research use.

  19. Numerical simulation of a class of models that combine several mechanisms of dissipation: Fracture, plasticity, viscous dissipation

    NASA Astrophysics Data System (ADS)

    Bonnetier, Eric; Jakabčin, Lukáš; Labbé, Stéphane; Replumaz, Anne

    2014-08-01

    We study a class of time evolution models that contain dissipation mechanisms exhibited by geophysical materials during deformation: plasticity, viscous dissipation and fracture. We formally prove that they satisfy a Clausius-Duhem type inequality. We describe a semi-discrete time evolution associated with these models, and report numerical 1D and 2D traction experiments, that illustrate that several dissipation regimes can indeed take place during the deformation. Finally, we report 2D numerical simulation of an experiment by Peltzer and Tapponnier, who studied the indentation of a layer of plasticine as an analogue model for geological materials.

  20. Underlying mechanism of combined effect of methamphetamine and morphine on lethality in mice and therapeutic potential of cooling.

    PubMed

    Namiki, Mizuho; Mori, Tomohisa; Sawaguchi, Toshiko; Ito, Shinobu; Suzuki, Tadashi

    2005-10-01

    An increase in polydrug abuse is a major problem worldwide. A previous study showed that coadministration of methamphetamine and morphine induced lethality in rodents and humans. However, the underlying mechanisms by which the lethality is increased by the coadministration of methamphetamine and morphine have not been fully understood. Therefore, the present study was designed to determine the mechanism of increased lethality induced by methamphetamine and morphine. Coadministered methamphetamine and morphine increased the lethality by more than 70% in BALB/c mice. Pretreatment with NMDA-receptor antagonists, such as MK-801 and 3-((R)-2-carboxypiperazin-4-yl) propyl-1-phosphonic acid (CPP), and benzamide [poly(ADP-ribose) polymerase (PARP) inhibitor] significantly attenuated the increased lethality induced by methamphetamine and morphine. Furthermore, the lethal effect induced by methamphetamine and morphine was completely attenuated by immediate cooling after the coadministration of methamphetamine and morphine. It has been reported that methamphetamine-induced neurotoxicity can be blocked by lowering the temperature, and this effect might be mediated by a reduction of release of free radicals. These results suggest that activation of NMDA receptors and PARP play an important role in the increased lethality induced by methamphetamine and morphine.

  1. Modification mechanism of praseodymium doping for the photocatalytic performance of TiO2: a combined experimental and theoretical study.

    PubMed

    Duan, Zhi-Gang; Zhao, Zong-Yan; Shi, Qing-Nan

    2015-07-15

    Impurity doping is a simple and efficient modification method to improve the photocatalytic performance of wide band gap photocatalysts. However, some basic and important issues about the mechanism of impurity doping modification still need to be further confirmed and explained. In the present work, Pr-doped TiO2 with a mono-phase crystal structure was prepared by a sol-gel method. Then, the crystal structure, binding information, optical absorption, and photocatalytic activity were systematically investigated. The experimental results show that Pr doping could significantly enhance the photocatalytic activity of TiO2, and the effects of modification on rutile TiO2 are more obvious than for anatase TiO2. In order to understand the underlying mechanism, density functional theory was utilized to calculate the crystal structure and electronic structure of pure and Pr-doped TiO2. The differences in electronic structure between anatase and rutile phases lead to the above photocatalytic performance. The experimental measurements and theoretical calculations mutually support each other in the present work. Two points are confirmed: the position of the band edge determines the redox activity of the photocatalyst, and the shallow energy bands induced by impurity doping could improve the photocatalytic performance.

  2. Combined experimental and quantum chemical study on the adsorption mechanism of phosphorous anions on the hydrotalcite surfaces

    NASA Astrophysics Data System (ADS)

    Mishima, Kenji; Zhang, Shuang; Minagawa, Sho; Kano, Naoki

    2016-08-01

    In the present work, the hydrotalcite-like compound [Mg6Al2(OH)16]CO3ṡ nH2O (shorted as MgAl-CO3) is synthesized and the adsorption of phosphorous anions, their adsorption performance on the surface of hydrotalcites, and its mechanism are analyzed. To theoretically clarify the adsorption mechanism and adsorption structures, we perform quantum chemistry calculations of reactants, locally stable states, transition states, and products among phosphorous anion, water, and hydrotalcite in a variety of pH ranges. The experimental result shows that the efficiency of phosphate removal does not depend on pH of the solution, with which the numerical results are consistent. In particular, we identify the factors of influencing the adsorption ratio in different pH ranges from the quantum chemistry calculations: the stability of locally stable states, and the energies and locations of potential barriers along the reaction pathway relative to those of the locally stable states. The results suggest that hydrotalcites synthesized in this work are suitable as sorbent materials for the adsorption and removal of phosphorous anions from aqueous solutions.

  3. Modification mechanism of praseodymium doping for the photocatalytic performance of TiO2: a combined experimental and theoretical study.

    PubMed

    Duan, Zhi-Gang; Zhao, Zong-Yan; Shi, Qing-Nan

    2015-07-15

    Impurity doping is a simple and efficient modification method to improve the photocatalytic performance of wide band gap photocatalysts. However, some basic and important issues about the mechanism of impurity doping modification still need to be further confirmed and explained. In the present work, Pr-doped TiO2 with a mono-phase crystal structure was prepared by a sol-gel method. Then, the crystal structure, binding information, optical absorption, and photocatalytic activity were systematically investigated. The experimental results show that Pr doping could significantly enhance the photocatalytic activity of TiO2, and the effects of modification on rutile TiO2 are more obvious than for anatase TiO2. In order to understand the underlying mechanism, density functional theory was utilized to calculate the crystal structure and electronic structure of pure and Pr-doped TiO2. The differences in electronic structure between anatase and rutile phases lead to the above photocatalytic performance. The experimental measurements and theoretical calculations mutually support each other in the present work. Two points are confirmed: the position of the band edge determines the redox activity of the photocatalyst, and the shallow energy bands induced by impurity doping could improve the photocatalytic performance. PMID:26130404

  4. Microstructure and Low-Temperature Mechanical Properties of 304 Stainless Steel Joints by PAW + GTAW Combined Welding

    NASA Astrophysics Data System (ADS)

    Liu, Kun; Li, Yajiang; Wang, Juan

    2016-08-01

    The combined double-pass process of plasma arc welding (PAW) + gas tungsten arc welding (GTAW) was performed on 304 austenitic stainless steel with the thickness of 12 mm. Results indicated that two different morphologies of ferrite (e.g., lathy δ-ferrite and skeletal δ-ferrite) were formed within the austenite matrix in PAW weld metal (PAW-WM). GTAW weld metal (GTAW-WM) was mainly composed of fine austenite and skeletal δ-ferrite. In transition zone between PAW-WM and GTAW-WM, epitaxial growth contributed to cellular dendritic crystals transforming into columnar crystals. The tensile strength of joint is about 700 MPa. The impact toughness of WM varied from 281 J (20 °C) to 122 (-196 °C), while the impact toughness of heat-affected zone (HAZ) varied from 205 J (20 °C) to 112 J (-196 °C).

  5. Correlating mechanical properties and anti-wear performance of tribofilms formed by ionic liquids, ZDDP and their combinations

    DOE PAGES

    Landauer, Alexander K.; Barnhill, William C.; Qu, Jun

    2016-03-10

    Here we examine the elasticity, hardness, and resistance-to-plastic-deformation (P/S2) measured via nanoindentation of several tribofilms and correlates these properties to friction and wear behavior. The tribofilms were generated by ball-on-plate reciprocating sliding lubricated by a base oil containing an ionic liquid, phosphonium-organophosphate or ammonium-organophosphate, zinc dialkyldithiophosphate (ZDDP), or combination of IL and ZDDP. Nanoindentation was conducted at room and elevated temperatures. While there seems little correlation between the tribofilm hardness and tribological behavior, a higher modulus generally leads to better friction and wear performance. Interestingly, a lower P/S2 ratio tends to reduce friction and improve wear protection, which is inmore » an opposite trend as reported for bulk materials. Ultimately, this is likely attributable to the dynamic, self-healing characteristics of tribofilms.« less

  6. Thiazole orange (TO) as a light-switch probe: a combined quantum-mechanical and spectroscopic study.

    PubMed

    Biancardi, Alessandro; Biver, Tarita; Marini, Alberto; Mennucci, Benedetta; Secco, Fernando

    2011-07-21

    A Density Functional Theory (DFT) study of the absorbance and fluorescence emission characteristics of the cyanine thiazole orange (TO) in solution and when intercalated in DNA was carried out in combination with spectrophotometric and spectrofluorometric experiments under different conditions (temperature, concentration, solvent viscosity). T-jump relaxation kinetics of the TO monomer-dimer conversion enabled the thermodynamic parameters of this process to be evaluated. The overall data collected provided information on the features of the "light-switch" by the fluorescent TO and the comparison between experimental and calculated photo-physical properties allowed us to explain and rationalize both shifts and quenching/enhancing effects on fluorescence due to solvation, dimerisation and intercalation in the DNA.

  7. Microstructure and Low-Temperature Mechanical Properties of 304 Stainless Steel Joints by PAW + GTAW Combined Welding

    NASA Astrophysics Data System (ADS)

    Liu, Kun; Li, Yajiang; Wang, Juan

    2016-10-01

    The combined double-pass process of plasma arc welding (PAW) + gas tungsten arc welding (GTAW) was performed on 304 austenitic stainless steel with the thickness of 12 mm. Results indicated that two different morphologies of ferrite (e.g., lathy δ-ferrite and skeletal δ-ferrite) were formed within the austenite matrix in PAW weld metal (PAW-WM). GTAW weld metal (GTAW-WM) was mainly composed of fine austenite and skeletal δ-ferrite. In transition zone between PAW-WM and GTAW-WM, epitaxial growth contributed to cellular dendritic crystals transforming into columnar crystals. The tensile strength of joint is about 700 MPa. The impact toughness of WM varied from 281 J (20 °C) to 122 (-196 °C), while the impact toughness of heat-affected zone (HAZ) varied from 205 J (20 °C) to 112 J (-196 °C).

  8. [The effect of combination epidural anesthesia techniques in upper abdominal surgery on the stress reaction, pain control and respiratory mechanics].

    PubMed

    Wiedemann, B; Leibe, S; Kätzel, R; Grube, U; Landgraf, R; Bierwolf, B

    1991-11-01

    Twenty-eight patients undergoing upper abdominal operations (mainly selective proximal vagotomy [SPV]) were referred for assessment of the hormonal metabolic reaction (adrenocorticotropic hormone [ACTH], arginine vasopressin [AVP], cortisol, and glucose), the postoperative pain reaction, and respiration according to the method of anesthesia (group 1: neuroleptanesthesia [NLA], group 2: NLA in combination with epidural opiate analgesia, group 3: NLA in combination with local anesthesia). To alleviate postoperative pain piritramide was systematically administered in group 1, whereas in groups 2 and 3 a thoracic epidural catheter was injected with morphine or bupivacaine. Postoperative analgesia was better in patients with epidural administration than in those with systemic application. On the 1st and 2nd postoperative days the vital capacity was statistically significantly higher by 10%-15% in groups 2 and 3 than in group 1. As expected, the neurohormonal and metabolic stress response was highest in all patients in the intraoperative and immediate postoperative phases: ACTH, AVP, and glucose levels were in most cases significantly higher compared with the initial values. However, cortisol levels decreased intraoperatively, probably as a result of the generally used induction agent etomidate. Comparison of the three methods of anesthesia revealed that all mean hormone levels analyzed in group 2 patients were lower both intraoperatively and 2 h postoperatively, which implies that epidurally administered morphine reduces the stress reaction, probably indirectly through additional selective alleviation of pain at the spinal cord level. The various differences in hormonal reactions of patients in groups 1 and 3 gave no clear evidence, however, of possible mitigation of the stress reaction by epidural local anesthetics in upper abdominal operations.

  9. Combined effects of TNF-α, IL-1β, and HIF-1α on MMP-2 production in ACL fibroblasts under mechanical stretch: an in vitro study.

    PubMed

    Wang, Yequan; Tang, Zhenyu; Xue, Ruyue; Singh, Gurinder K; Shi, Kunning; Lv, Yonggang; Yang, Li

    2011-07-01

    The dynamics between inflammatory factors, mechanical stress, and healing factors, in an intra-articular joint, are very complex after injury. Injury to intra-articular tissue [anterior cruciate ligament (ACL), synovium] results in hypoxia, accumulation of various pro-inflammatory factors, cytokines, and metalloproteases. Although the presence of increased amounts of matrix-metalloproteinases (MMP) in the joint fluid after knee injury is considered the key factor for ACL poor healing ability; however, the exact role of collective participants of the joint fluid on MMP-2 activity and production has not been fully studied yet. To investigate the combined effects of mechanical injury, inflammation and hypoxia induced factor-1α (HIF-1α) on induction of MMP-2; we mimicked the microenvironment of joint cavity after ACL injury. The results show that TNF-α and IL-1β elevate the activity of MMP-2 in a dose- and time-dependent manner. In addition, mechanical stretch further enhances the MMP-2 protein levels with TNF-α, IL-1β, and their mixture. CoCl(2) -induced HIF-1α (100 and 500 µM) also increases the levels and activity of MMP-2. Mechanical stretch has a strong additional effect on MMP-2 production with HIF-1α. Our results conclude that mechanical injury, HIF-1α and inflammatory factors collectively induce increased MMP-2 production in ACL fibroblasts, which was inhibited by NF-κB pathway inhibitor (Bay-11-7082).

  10. Design and validation of a novel bioreactor principle to combine online micro-computed tomography monitoring and mechanical loading in bone tissue engineering.

    PubMed

    Hagenmüller, Henri; Hitz, Marco; Merkle, Hans P; Meinel, Lorenz; Müller, Ralph

    2010-01-01

    Mechanical loading plays an important role in bone remodeling in vivo and, therefore, has been suggested as a key parameter in stem cell-based engineering of bone-like tissue in vitro. However, the optimization of loading protocols during stem cell differentiation and subsequent bone-like tissue formation is challenged by multiple input factors, which are difficult to control and validate. These include the variable cellular performance of cells harvested from different patients, nonstandardized culture media components, the choice of the biomaterial forming the scaffold, and its morphology, impacting a broader validity of mechanical stimulation regimens. To standardize the cell culture of bone-like tissue constructs, we suggest the involvement of time-lapsed feedback loops. For this purpose we present a prototype bioreactor that combines online, nondestructive monitoring using micro-computed tomography and direct mechanical loading of three-dimensional tissue engineering constructs. Validation of this system showed displacement steps down to 1 microm and cyclic sinusoidal loadings of up to 10 Hz. Load detection resolution was 0.01 N, and micro-computed tomography data were of high quality. For the first time, the developed bioreactor links time-lapsed, nondestructive, and dynamic imaging with mechanical stimulation, designed for cell culture under sterile conditions. This system is believed to substantially improve today's experimental options to study and optimize osteogenic stem cell culture and differentiation at the interface with mechanical stimulation.

  11. Design and validation of a novel bioreactor principle to combine online micro-computed tomography monitoring and mechanical loading in bone tissue engineering

    NASA Astrophysics Data System (ADS)

    Hagenmüller, Henri; Hitz, Marco; Merkle, Hans P.; Meinel, Lorenz; Müller, Ralph

    2010-01-01

    Mechanical loading plays an important role in bone remodeling in vivo and, therefore, has been suggested as a key parameter in stem cell-based engineering of bone-like tissue in vitro. However, the optimization of loading protocols during stem cell differentiation and subsequent bone-like tissue formation is challenged by multiple input factors, which are difficult to control and validate. These include the variable cellular performance of cells harvested from different patients, nonstandardized culture media components, the choice of the biomaterial forming the scaffold, and its morphology, impacting a broader validity of mechanical stimulation regimens. To standardize the cell culture of bone-like tissue constructs, we suggest the involvement of time-lapsed feedback loops. For this purpose we present a prototype bioreactor that combines online, nondestructive monitoring using micro-computed tomography and direct mechanical loading of three-dimensional tissue engineering constructs. Validation of this system showed displacement steps down to 1 μm and cyclic sinusoidal loadings of up to 10 Hz. Load detection resolution was 0.01 N, and micro-computed tomography data were of high quality. For the first time, the developed bioreactor links time-lapsed, nondestructive, and dynamic imaging with mechanical stimulation, designed for cell culture under sterile conditions. This system is believed to substantially improve today's experimental options to study and optimize osteogenic stem cell culture and differentiation at the interface with mechanical stimulation.

  12. ELECTROSPUN MESOFIBERS, A NOVEL BIODEGRADABLE PHEROMONE DISPENSER TECHNOLOGY, ARE COMBINED WITH MECHANICAL DEPLOYMENT FOR EFFICIENT IPM OF LOBESIA BOTRANA IN VINEYARDS.

    PubMed

    Hummel, Hans E; Langner, S S; Breuer, M

    2015-01-01

    Behaviour modifying pheromones are well known agents for disrupting mating communication of pest insects. For optimal activity, they must be dispensed in time and space at a quantitatively measurable, predetermined release rate covering the flight period of the target species. Pheromones appeal to environmentally conscientious entomologists for their biodegradability, non-toxicity and ecological compatibility. In attempts of combining the virtues of pheromones, suitable slow release dispensers, and their mechanical deployment, an ecologically sensible, reasonably priced and patented procedure was developed and tested with the vineyard pest Lobesia botrana (Lep.: Tortricidae). It is characterized by (1) Electrospun mesofibers with diameters ranging from 0.6 to 3.5 micrometres, containing disruptants and dispensing it by slow release diffusion into the crop, (2) simultaneous application of the fully biodegradable combination of pheromone with Ecoflex polyester mesofiber, (3) combination of mechanical deployment by multi-purpose cultivators of the prefabricated pheromone dispensers with other simultaneous cultivation measures, and thus further reducing labour time and treatment costs. The dispensers are biodegradable within half a year without leaving any objectionable residues. In the standard eco-toxicology tests pheromone dispensers are harmless to non-target organisms. The disruptive effect of one treatment lasts for seven weeks which covers well one of several flight periods of L. botrana.

  13. Analysis of CO2 convection mechanisms associated to surface heating, by combining remote sensing data and in situ measurements

    NASA Astrophysics Data System (ADS)

    Tello, Marivi; Curcoll, Roger; Font, Anna; Morgu, Josep Anton; Rod, Xavier

    Assessing the mechanisms involved in the variability of carbon fluxes is crucial for the under-standing of the changing earth dynamics. In that sense, the aim of this work is to analyze CO2 convection mechanisms at a regional scale in the boundary layer and the lower troposphere by means of cross correlation of land surface temperature data, radio-soundings, wind speeds and in situ measurements of CO2 atmospheric mixing ratios. Since data is easier to acquire, ground level horizontal CO2 fluxes have been widely studied. In the contrary, vertical ones are still subject to uncertainties, even if they are necessary to understand 3D CO2 variability in the atmosphere. In particular, this paper focuses on the relationship between surface heating, convection and CO2 concentrations at different heights and, more generally, on the energy transfer between the surface and the air. The monitored area corresponds to a region on the North Eastern Iberian Peninsula, mainly devoted to agricultural activities. Different types of land covers are observed. On the one hand, in situ data has been collected by several flights during 2007 along the parallel 42o N following the "Crown" aircraft sampling approach [1] that integrates CO2 data obtained through horizontal transects and vertical profiles. This particular configuration is especially well suited for the evaluation of both horizontal and vertical CO2 fluxes. On the other hand, the radiometric land surface temperatures are obtained from the MODIS instrument onboard the Terra and the Aqua satellites. Besides, a flight campaign with an airborne sensor along the same transect in the parallel 42o N has been proposed in the scope of the MIDAS-6 project recently submitted. This project plans to improve soil moisture and ocean salinity products of the SMOS sensor recently launched and to demonstrate its applications. This will allow the study of moisture patterns in the monitored area at two different scales: that of the data collected

  14. Time-frequency methods and voluntary ramped-frequency breathing: a powerful combination for exploration of human neurophysiological mechanisms

    PubMed Central

    Stankovski, Tomislav; Cooke, William H.; Rudas, László; Stefanovska, Aneta

    2013-01-01

    We experimentally altered the timing of respiratory motoneuron activity as a means to modulate and better understand otherwise hidden human central neural and hemodynamic oscillatory mechanisms. We recorded the electrocardiogram, finger photoplethysmographic arterial pressure, tidal carbon dioxide concentrations, and muscle sympathetic nerve activity in 13 healthy supine young men who gradually increased or decreased their breathing frequencies between 0.05 and 0.25 Hz over 9-min periods. We analyzed results with traditional time- and frequency-domain methods, and also with time-frequency methods (wavelet transform, wavelet phase coherence, and directional coupling). We determined statistical significance and identified frequency boundaries by comparing measurements with randomly generated surrogates. Our results support several major conclusions. First, respiration causally modulates both sympathetic (weakly) and vagal motoneuron (strongly) oscillations over a wide frequency range—one that extends well below the frequency of actual breaths. Second, breathing frequency broadly modulates vagal baroreflex gain, with peak gains registered in the low frequency range. Third, breathing frequency does not influence median levels of sympathetic or vagal activity over time. Fourth, phase relations between arterial pressure and sympathetic and vagal motoneurons are unaffected by breathing, and are therefore likely secondary to intrinsic responsiveness of these motoneurons to other synaptic inputs. Finally, breathing frequency does not affect phase coherence between diastolic pressure and muscle sympathetic oscillations, but it augments phase coherence between systolic pressure and R-R interval oscillations over a limited portion of the usual breathing frequency range. These results refine understanding of autonomic oscillatory processes and those physiological mechanisms known as the human respiratory gate. PMID:24114700

  15. A combined binding mechanism of nonionic ethoxylated surfactants to bovine serum albumin revealed by fluorescence and circular dichroism.

    PubMed

    Iovescu, Alina; Băran, Adriana; Stîngă, Gabriela; Cantemir-Leontieş, Anca Ruxandra; Maxim, Monica Elisabeta; Anghel, Dan Florin

    2015-12-01

    The study systematically investigates aqueous mixtures of fixed bovine serum albumin (BSA) and various ethoxylated nonionic surfactants belonging to a homologous series or not. Mono-disperse tetra-(C12E4), hexa-(C12E6) and octa-ethyleneglycol mono-n-dodecyl ether (C12E8), and poly-disperse eicosa-ethyleneglycol mono-n-tetradecyl ether (C14EO20) are respectively employed. Fluorescence and circular dichroism measurements are performed at surfactant/protein molar ratios (rm)s lower and higher than one. We aim to get new insights into the binding mechanism of these species and to differentiate among the interaction abilities of these surfactants. The relative magnitude of the binding thermodynamic parameters by fluorescence, and the increase of α-helix prove that hydrogen bonding drives the interaction next to the hydrophobic attraction. C12En (n=4,6,8) develop more H bonds with the albumin than C14EO20 owing to a zigzag conformation of their short ethyleneoxide chains. Among the homologous surfactants, C12E6 has a slightly stronger interaction with BSA due to a maximal number of H bonds at a minimal hindering. Static fluorescence and dynamic fluorescence indicate an inter-conversion between the tryptophan (Trp) rotamers which happens around the surfactants critical micellar concentration. For C14EO20, the meander conformation of the polar group determines a less evident conversion of the Trp rotamers and smaller α-helix rise. Binding isotherms of the homologous surfactants and the fluorescence quenching mechanism by C12E6 are also provided.

  16. Daptomycin resistance mechanisms in clinically derived Staphylococcus aureus strains assessed by a combined transcriptomics and proteomics approach

    PubMed Central

    Fischer, Adrien; Yang, Soo-Jin; Bayer, Arnold S.; Vaezzadeh, Ali R.; Herzig, Sébastien; Stenz, Ludwig; Girard, Myriam; Sakoulas, George; Scherl, Alexander; Yeaman, Michael R.; Proctor, Richard A.; Schrenzel, Jacques; François, Patrice

    2011-01-01

    Objectives The development of daptomycin resistance in Staphylococcus aureus is associated with clinical treatment failures. The mechanism(s) of such resistance have not been clearly defined. Methods We studied an isogenic daptomycin-susceptible (DAPS) and daptomycin-resistant (DAPR) S. aureus strain pair (616; 701) from a patient with relapsing endocarditis during daptomycin treatment, using comparative transcriptomic and proteomic techniques. Results Minor differences in the genome content were found between strains by DNA hybridization. Transcriptomic analyses identified a number of genes differentially expressed in important functional categories: cell division; metabolism of bacterial envelopes; and global regulation. Of note, the DAPR isolate exhibited reduced expression of the major cell wall autolysis gene coincident with the up-regulation of genes involved in cell wall teichoic acid production. Using quantitative (q)RT–PCR on the gene cadre putatively involved in cationic peptide resistance, we formulated a putative regulatory network compatible with microarray data sets, mainly implicating bacterial envelopes. Of interest, qRT–PCR of this same gene cadre from two distinct isogenic DAPS/DAPR clinical strain pairs revealed evidence of other strain–dependent networks operative in the DAPR phenotype. Comparative proteomics of 616 versus 701 revealed a differential abundance of proteins in various functional categories, including cell wall-associated targets and biofilm formation proteins. Phenotypically, strains 616 and 701 showed major differences in their ability to develop bacterial biofilms in the presence of the antibacterial lipid, oleic acid. Conclusions Compatible with previous in vitro observations, in vivo-acquired DAPR in S. aureus is a complex, multistep phenomenon involving: (i) strain-dependent phenotypes; (ii) transcriptome adaptation; and (iii) modification of the lipid and protein contents of cellular envelopes. PMID:21622973

  17. Combined Spectroscopic and Calorimetric Studies to Reveal Absorption Mechanisms and Conformational Changes of Protein on Nanoporous Biomaterials

    PubMed Central

    Ahmadi, Saharnaz; Farokhi, Maryam; Padidar, Parisa; Falahati, Mojtaba

    2015-01-01

    In this study the effect of surface modification of mesoporous silica nanoparticles (MSNs) on its adsorption capacities and protein stability after immobilization of beta-lactoglobulin B (BLG-B) was investigated. For this purpose, non-functionalized (KIT-6) and aminopropyl-functionalized cubic Ia3d mesoporous silica ([n-PrNH2-KIT-6]) nanoparticles were used as nanoporous supports. Aminopropyl-functionalized mesoporous nanoparticles exhibited more potential candidates for BLG-B adsorption and minimum BLG leaching than non-functionalized nanoparticles. It was observed that the amount of adsorbed BLG is dependent on the initial BLG concentration for both KIT-6 and [n-PrNH2-KIT-6] mesoporous nanoparticles. Also larger amounts of BLG-B on KIT-6 was immobilized upon raising the temperature of the medium from 4 to 55 °C while such increase was undetectable in the case of immobilization of BLG-B on the [n-PrNH2-KIT-6]. At temperatures above 55 °C the amounts of adsorbed BLG on both studied nanomaterials decreased significantly. By Differential scanning calorimetry or DSC analysis the heterogeneity of the protein solution and increase in Tm may indicate that immobilization of BLG-B onto the modified KIT-6 results in higher thermal stability compared to unmodified one. The obtained results provide several crucial factors in determining the mechanism(s) of protein adsorption and stability on the nanostructured solid supports and the development of engineered nano-biomaterials for controlled drug-delivery systems and biomimetic interfaces for the immobilization of living cells. PMID:26230687

  18. Mechanisms behind injecting the combination of nano-clay particles and polymer solution for enhanced oil recovery

    NASA Astrophysics Data System (ADS)

    Khalili Nezhad, Seyyed Shahram; Cheraghian, Goshtasp

    2016-08-01

    Laboratory investigations and field applications have proved injection of polymer solution to be an effective means to improve oil recovery for reservoirs of medium oil viscosity. The incremental oil produced in this case is the result of an increase in areal and vertical sweep efficiencies. Biopolymers and synthetic polymers are the major categories used in the petroleum industry for specific reasons. Biopolymers like xanthan are limited in their application as they are more susceptible to biodegradation. Synthetic polymers like Hydrolyzed PolyAcrylaMide (HPAM) have a much wider application as they are less susceptible to biodegradation. Furthermore, development of nanotechnology has successfully provided technical and economical viable alternatives for present materials. The objective of this study is to investigate the effect of combining clay nanoparticles with polymer solution on oil recovery. This paper includes a history match of both one-dimensional and two-dimensional polymer floods using a three-dimensional numerical model for fluid flow and mass transport. Results indicated that the amount of polymer adsorption decreased when clay nanoparticles were added to the PolyAcrylaMide solution; however, mobility ratio improvement is believed to be the main contributor for the proposed method in order to enhance much oil recovery compared to xanthan flood and HPAM flood.

  19. Ultrafine-Grained Aluminum Processed by a Combination of Hot Isostatic Pressing and Dynamic Plastic Deformation: Microstructure and Mechanical Properties

    NASA Astrophysics Data System (ADS)

    Dirras, G.; Chauveau, T.; Abdul-Latif, A.; Gubicza, J.; Ramtani, S.; Bui, Q.; Hegedűs, Z.; Bacroix, B.

    2012-04-01

    Commercial-purity (99 wt pct), bulk, ultrafine-grained aluminum samples were produced by a two-step process that combines powder consolidation by hot isostatic pressing and dynamic plastic deformation. The compaction step yielded crystallographic texture-free specimens with an average grain size of approximately 2 μm. Then, some of the consolidated specimens were deformed dynamically at room temperature at an initial strain rate of 370 seconds-1 and up to an axial strain of ɛ = 1.25. After dynamic plastic deformation, the grain size and the dislocation density were approximately 500 nm and 1014 m-2, respectively. The yield strength was approximately 77 MPa for the as-consolidated sample, which increased up to approximately 103 MPa and 120 MPa for the impacted samples along the axial and radial directions, respectively. The compression stress as a function of strain showed saturation behavior for the axially deformed samples, whereas the specimens deformed along the radial direction exhibited significant strain softening. The latter behavior is explained mainly by the weakening of the crystallographic texture that occurred because of the strain-path change along the radial direction.

  20. The Combination Therapy with Zoledronic Acid and Propranolol Improves the Trabecular Microarchitecture and Mechanical Property in an Rat Model of Postmenopausal Osteoporosis

    PubMed Central

    Razdan, Rema; Mahapatra, D. Roy

    2014-01-01

    We conducted the present study to investigate the therapeutic effects of propranolol (PRO), alone and in combination with the antiresorptive agent ZOL, in a rat model of postmenopausal osteoporosis. Female Wistar rats were OVX or sham-operated at 3 months of age. Twelve weeks after surgery, rats were randomized into six groups: (1) sham + vehicle, (2) OVX + vehicle, (3) OVX + ZOL (100 μg/kg, i.v. single dose), (4) OVX + ZOL (50 μg/kg, i.v. single dose), (5) OVX + PRO (0.1 mg/kg, s.c. 5 days per week), and (6) OVX + ZOL (50 μg/kg, i.v. single dose) + PRO (0.1 mg/kg, s.c. 5 days per week) for 12 weeks. At the end of treatment study, various bone parameters were evaluated. With respect to improvement in the mechanical strength of the lumbar spine and the femoral mid-shaft, the combination treatment of ZOL and PRO was more effective than each drug administered as a monotherapy. Moreover, combination therapy using ZOL and PRO preserved the trabecular microarchitecture better than single-drug therapy using ZOL or PRO in OVX rats. These data suggest that combination therapy with ZOL plus PRO represents a potentially useful therapeutic option for patients with osteoporosis. PMID:24800099

  1. Influence of extremely low frequency, low energy electromagnetic fields and combined mechanical stimulation on chondrocytes in 3-D constructs for cartilage tissue engineering.

    PubMed

    Hilz, Florian M; Ahrens, Philipp; Grad, Sibylle; Stoddart, Martin J; Dahmani, Chiheb; Wilken, Frauke L; Sauerschnig, Martin; Niemeyer, Philipp; Zwingmann, Jörn; Burgkart, Rainer; von Eisenhart-Rothe, Rüdiger; Südkamp, Norbert P; Weyh, Thomas; Imhoff, Andreas B; Alini, Mauro; Salzmann, Gian M

    2014-02-01

    Articular cartilage, once damaged, has very low regenerative potential. Various experimental approaches have been conducted to enhance chondrogenesis and cartilage maturation. Among those, non-invasive electromagnetic fields have shown their beneficial influence for cartilage regeneration and are widely used for the treatment of non-unions, fractures, avascular necrosis and osteoarthritis. One very well accepted way to promote cartilage maturation is physical stimulation through bioreactors. The aim of this study was the investigation of combined mechanical and electromagnetic stress affecting cartilage cells in vitro. Primary articular chondrocytes from bovine fetlock joints were seeded into three-dimensional (3-D) polyurethane scaffolds and distributed into seven stimulated experimental groups. They either underwent mechanical or electromagnetic stimulation (sinusoidal electromagnetic field of 1 mT, 2 mT, or 3 mT; 60 Hz) or both within a joint-specific bioreactor and a coil system. The scaffold-cell constructs were analyzed for glycosaminoglycan (GAG) and DNA content, histology, and gene expression of collagen-1, collagen-2, aggrecan, cartilage oligomeric matrix protein (COMP), Sox9, proteoglycan-4 (PRG-4), and matrix metalloproteinases (MMP-3 and -13). There were statistically significant differences in GAG/DNA content between the stimulated versus the control group with highest levels in the combined stimulation group. Gene expression was significantly higher for combined stimulation groups versus static control for collagen 2/collagen 1 ratio and lower for MMP-13. Amongst other genes, a more chondrogenic phenotype was noticed in expression patterns for the stimulated groups. To conclude, there is an effect of electromagnetic and mechanical stimulation on chondrocytes seeded in a 3-D scaffold, resulting in improved extracellular matrix production.

  2. Development of a 3D parallel mechanism robot arm with three vertical-axial pneumatic actuators combined with a stereo vision system.

    PubMed

    Chiang, Mao-Hsiung; Lin, Hao-Ting

    2011-01-01

    This study aimed to develop a novel 3D parallel mechanism robot driven by three vertical-axial pneumatic actuators with a stereo vision system for path tracking control. The mechanical system and the control system are the primary novel parts for developing a 3D parallel mechanism robot. In the mechanical system, a 3D parallel mechanism robot contains three serial chains, a fixed base, a movable platform and a pneumatic servo system. The parallel mechanism are designed and analyzed first for realizing a 3D motion in the X-Y-Z coordinate system of the robot's end-effector. The inverse kinematics and the forward kinematics of the parallel mechanism robot are investigated by using the Denavit-Hartenberg notation (D-H notation) coordinate system. The pneumatic actuators in the three vertical motion axes are modeled. In the control system, the Fourier series-based adaptive sliding-mode controller with H(∞) tracking performance is used to design the path tracking controllers of the three vertical servo pneumatic actuators for realizing 3D path tracking control of the end-effector. Three optical linear scales are used to measure the position of the three pneumatic actuators. The 3D position of the end-effector is then calculated from the measuring position of the three pneumatic actuators by means of the kinematics. However, the calculated 3D position of the end-effector cannot consider the manufacturing and assembly tolerance of the joints and the parallel mechanism so that errors between the actual position and the calculated 3D position of the end-effector exist. In order to improve this situation, sensor collaboration is developed in this paper. A stereo vision system is used to collaborate with the three position sensors of the pneumatic actuators. The stereo vision system combining two CCD serves to measure the actual 3D position of the end-effector and calibrate the error between the actual and the calculated 3D position of the end-effector. Furthermore, to

  3. Kinetic analysis of acid orange 7 degradation by pulsed discharge plasma combined with activated carbon and the synergistic mechanism exploration.

    PubMed

    Guo, He; Wang, Huijuan; Wu, Qiangshun; Zhou, Guangshun; Yi, Chengwu

    2016-09-01

    The synergistic technique of pulsed discharge plasma (PDP) and activated carbon (AC) was built to investigate the kinetics of acid orange 7 (AO7) degradation under different conditions of AC addition, electrode gap, initial pH value of solution, gas variety and gas flow rate. Emission spectra of OH and O, UV-vis absorption spectra of the AO7 solution and TOC removal were measured to illustrate the synergistic mechanism of the PDP and the AC. The obtained results indicated that the kinetic constant of AO7 degradation increased from 0.00947 min(-1) to 0.01419 min(-1) when 4 g AC was added into the PDP system; AO7 degradation was higher in the case of alkaline solution when oxygen was used as the flow gas in the PDP/AC system, 2 L/min oxygen flow was more favorable for the degradation. Results of the relative emission intensities of OH and O indicated the catalytic effect of the AC on the active species formation as well as the important role of the two radicals for the AO7 degradation. There was no new peaks appeared by the UV-vis analysis of the AO7 solution after 60 min treatment. The highest TOC removal in the PDP/AC system was 30.3%, which was achieved under the condition of 4 L/min air flow rate and 3 initial pH value. PMID:27295438

  4. Molecular dynamics study of the isothermal crystallization mechanism of polyethylene chain: the combined effects of chain length and temperature.

    PubMed

    Gao, Rui; He, Xuelian; Zhang, Haiyang; Shao, Yunqi; Liu, Zhen; Liu, Boping

    2016-03-01

    A molecular level understanding of the polyethylene (PE) crystallization process was elucidated by molecular dynamics simulation of three states, with varying chain length and temperature. The process can be classified into the following three states: (1) nucleation controlled state, (2) competitive state of crystal growth process and new nuclei formation, and (3) crystal growth controlled state, which could be quantified by the evolution of nuclei number. With increasing chain length, two phenomena occur: the single crystallization mechanism changes from state (1) to (3), and the crystal size increases while the b/a axial ratio in the lateral surface decreases. These changes can be explained from a thermodynamic point of view, in that the van der Waals (vdW) interaction per CH2 unit is strengthened and more nucleation sites are generated for longer chain. Size effect (meaning different surface fractions when the chain collapses into a globule) was an important factor determining vdW energy per unit and the crystallization states of a single PE chain. On the other hand, the crystallization states were independent of chain length for short chains systems with the same size effect. In both conditions, a long chain generates multi-crystal domains, and a short chain prefers a single crystal domain. Our results not only provide molecular level evidence for crystallization states but also clarify the influence of chain length on the crystallization process.

  5. Mechanism of ceroid formation in atherosclerotic plaque: in situ studies using a combination of Raman and fluorescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Haka, Abigail S.; Kramer, John R.; Dasari, Ramachandra R.; Fitzmaurice, Maryann

    2011-01-01

    Accumulation of the lipid-protein complex ceroid is a characteristic of atherosclerotic plaque. The mechanism of ceroid formation has been extensively studied, because the complex is postulated to contribute to plaque irreversibility. Despite intensive research, ceroid deposits are defined through their fluorescence and histochemical staining properties, while their composition remains unknown. Using Raman and fluorescence spectral microscopy, we examine the composition of ceroid in situ in aorta and coronary artery plaque. The synergy of these two types of spectroscopy allows for identification of ceroid via its fluorescence signature and elucidation of its chemical composition through the acquisition of a Raman spectrum. In accordance with in vitro predictions, low density lipoprotein (LDL) appears within the deposits primarily in its peroxidized form. The main forms of modified LDL detected in both coronary artery and aortic plaques are peroxidation products from the Fenton reaction and myeloperoxidase-hypochlorite pathway. These two peroxidation products occur in similar concentrations within the deposits and represent ~40 and 30% of the total LDL (native and peroxidized) in the aorta and coronary artery deposits, respectively. To our knowledge, this study is the first to successfully employ Raman spectroscopy to unravel a metabolic pathway involved in disease pathogenesis: the formation of ceroid in atherosclerotic plaque.

  6. Chemoprotective epigenetic mechanisms in a colorectal cancer model: Modulation by n-3 PUFA in combination with fermentable fiber

    PubMed Central

    Triff, Karen; Kim, Eunjoo; Chapkin, Robert S.

    2015-01-01

    Colorectal cancer is the third major cause of cancer-related mortality in both men and women worldwide. The beneficial role of n-3 polyunsaturated fatty acids (PUFA) in preventing colon cancer is substantiated by experimental, epidemiological, and clinical data. From a mechanistic perspective, n-3 PUFA are pleiotropic and multifaceted with respect to their molecular mechanisms of action. For example, this class of dietary lipid uniquely modulates membrane and nuclear receptors, sensors/ion channels, and membrane structure/cytoskeletal function, thereby regulating signaling processes that influence patterns of gene expression and cell phenotype. In addition, n-3 PUFA can synergize with other potential chemoprotective agents known to reprogram the chromatin landscape, such as the fermentable fiber product, butyrate. Nutri-epigenomics is an emerging field of research that is focused on the interaction between nutrition and epigenetics. Epigenetics refers to a group of heterogeneous processes that regulate transcription without changing the DNA coding sequence, ranging from DNA methylation, to histone tail modifications and transcription factor activity. One implication of the nutri-epigenome is that it may be possible to reprogram epigenetic marks that are associated with increased disease risk by nutritional or lifestyle interventions. This review will focus on the nutri-epigenomic role of n-3 PUFA, particularly DHA, as well as the combinatorial effects of n-3 PUFA and fermentable fiber in relation to colon cancer. PMID:25938013

  7. Kinetic analysis of acid orange 7 degradation by pulsed discharge plasma combined with activated carbon and the synergistic mechanism exploration.

    PubMed

    Guo, He; Wang, Huijuan; Wu, Qiangshun; Zhou, Guangshun; Yi, Chengwu

    2016-09-01

    The synergistic technique of pulsed discharge plasma (PDP) and activated carbon (AC) was built to investigate the kinetics of acid orange 7 (AO7) degradation under different conditions of AC addition, electrode gap, initial pH value of solution, gas variety and gas flow rate. Emission spectra of OH and O, UV-vis absorption spectra of the AO7 solution and TOC removal were measured to illustrate the synergistic mechanism of the PDP and the AC. The obtained results indicated that the kinetic constant of AO7 degradation increased from 0.00947 min(-1) to 0.01419 min(-1) when 4 g AC was added into the PDP system; AO7 degradation was higher in the case of alkaline solution when oxygen was used as the flow gas in the PDP/AC system, 2 L/min oxygen flow was more favorable for the degradation. Results of the relative emission intensities of OH and O indicated the catalytic effect of the AC on the active species formation as well as the important role of the two radicals for the AO7 degradation. There was no new peaks appeared by the UV-vis analysis of the AO7 solution after 60 min treatment. The highest TOC removal in the PDP/AC system was 30.3%, which was achieved under the condition of 4 L/min air flow rate and 3 initial pH value.

  8. Unfolding the mechanism of the AAA+ unfoldase VAT by a combined cryo-EM, solution NMR study.

    PubMed

    Huang, Rui; Ripstein, Zev A; Augustyniak, Rafal; Lazniewski, Michal; Ginalski, Krzysztof; Kay, Lewis E; Rubinstein, John L

    2016-07-19

    The AAA+ (ATPases associated with a variety of cellular activities) enzymes play critical roles in a variety of homeostatic processes in all kingdoms of life. Valosin-containing protein-like ATPase of Thermoplasma acidophilum (VAT), the archaeal homolog of the ubiquitous AAA+ protein Cdc48/p97, functions in concert with the 20S proteasome by unfolding substrates and passing them on for degradation. Here, we present electron cryomicroscopy (cryo-EM) maps showing that VAT undergoes large conformational rearrangements during its ATP hydrolysis cycle that differ dramatically from the conformational states observed for Cdc48/p97. We validate key features of the model with biochemical and solution methyl-transverse relaxation optimized spectroscopY (TROSY) NMR experiments and suggest a mechanism for coupling the energy of nucleotide hydrolysis to substrate unfolding. These findings illustrate the unique complementarity between cryo-EM and solution NMR for studies of molecular machines, showing that the structural properties of VAT, as well as the population distributions of conformers, are similar in the frozen specimens used for cryo-EM and in the solution phase where NMR spectra are recorded.

  9. Combined effect of pulse electron beam treatment and thin hydroxyapatite film on mechanical features of biodegradable AZ31 magnesium alloy

    NASA Astrophysics Data System (ADS)

    Surmeneva, M. A.; Tyurin, A. I.; Teresov, A. D.; Koval, N. N.; Pirozhkova, T. S.; Shuvarin, I. A.; Surmenev, R. A.

    2015-11-01

    The morphology, elemental, phase composition, nanohardness, and Young's modulus of the hydroxyapatite (HA) coating deposited via radio frequency (RF) magnetron sputtering onto the AZ31 surface were investigated by atomic force microscopy (AFM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and nanoindentationtechniques. The calcium phosphate (Ca/P) molar ratio of the HA coating deposited via RF-magnetron sputtering onto AZ31 substrates according to EDX was 1.57+0.03. The SEM experiments revealed significant differences in the morphology of the HA film deposited on untreated and treated with the pulsed electron beam (PEB) AZ31 substrate. Nanoindentation studies demonstrated significant differences in the mechanical responses of the HA film deposited on the initial and PEB-modified AZ31 substrates. The nanoindentation hardness and the Young's modulus of the HA film on the magnesium alloy modified using the PEB treatment were higher than that of the HA layer on the untreated substrate. Moreover, the HA film fabricated onto the PEB-treated surface was more resistant to plastic deformation than the same film on the untreated AZ31 surface.

  10. Combined electromagnetic and permanent magnet undulator to achieve higher field and easier field variation without mechanical movement

    SciTech Connect

    Bogachenkov, V.A.; Papadichev, V.A.

    1995-12-31

    Hybrid or pure permanent magnet undulators (PMU) are widely used because they have high field quality, allow easy field correction and do not consume power. Their main drawback is the necessity of moving one half of the magnet relative to the other to change field value, which requires a high precision, remotely controlled (and thus costly) driving system On the other hand, electromagnetic undulatory (EMU) have no problem with field variation, but consume too much power (100 - 400 kW) for high fields. Adding permanent magnets to EMU results in a considerable decrease of power consumption, while retaining the advantage of easily changing field level. A model of a CW combined EM+PM plane undulator having a 4.8 cm period and 8 periods long is described. It is simple in design and cheap in manufacturing: magnet yokes are made of soft steel rings in which 1.6 cm air gaps were cut to form pole faces. Odd yokes are placed to one side of the undulator axis and even yokes to the other with the air gaps on the axis. Each set of yokes is excited by its own separate winding of simple racetrack shape. Undulator deflection parameter K = 1.1 (B = 2.4 kG) can be reached at a 0.78kW power level, i.e., less than 100 W per period, while without PM only a maximum K = 0.8 can be obtained and requires 4 kW power. No water cooling is needed, which greatly simplifies undulator design. The undulator was not optimized relative to the axial-air-gap to ring-width ratio: one might expect some increase in field level for thinner rings. Field amplitude depends also on relative transverse position of odd and even pole faces.

  11. A Framework for Local Mechanical Characterization of Atherosclerotic Plaques: Combination of Ultrasound Displacement Imaging and Inverse Finite Element Analysis.

    PubMed

    Akyildiz, Ali C; Hansen, Hendrik H G; Nieuwstadt, Harm A; Speelman, Lambert; De Korte, Chris L; van der Steen, Antonius F W; Gijsen, Frank J H

    2016-04-01

    Biomechanical models have the potential to predict plaque rupture. For reliable models, correct material properties of plaque components are a prerequisite. This study presents a new technique, where high resolution ultrasound displacement imaging and inverse finite element (FE) modeling is combined, to estimate material properties of plaque components. Iliac arteries with plaques were excised from 6 atherosclerotic pigs and subjected to an inflation test with pressures ranging from 10 to 120 mmHg. The arteries were imaged with high frequency 40 MHz ultrasound. Deformation maps of the plaques were reconstructed by cross correlation of the ultrasound radiofrequency data. Subsequently, the arteries were perfusion fixed for histology and structural components were identified. The histological data were registered to the ultrasound data to construct FE model of the plaques. Material properties of the arterial wall and the intima of the atherosclerotic plaques were estimated using a grid search method. The computed displacement fields showed good agreement with the measured displacement fields, implying that the FE models were able to capture local inhomogeneities within the plaque. On average, nonlinear stiffening of both the wall and the intima was observed, and the wall of the atheroslcerotic porcine iliac arteries was markedly stiffer than the intima (877 ± 459 vs. 100 ± 68 kPa at 100 mmHg). The large spread in the data further illustrates the wide variation of the material properties. We demonstrated the feasibility of a mixed experimental-numerical framework to determine the material properties of arterial wall and intima of atherosclerotic plaques from intact arteries, and concluded that, due to the observed variation, plaque specific properties are required for accurate stress simulations.

  12. Communication: Slow supramolecular mode in amine and thiol derivatives of 2-ethyl-1-hexanol revealed by combined dielectric and shear-mechanical studies.

    PubMed

    Adrjanowicz, K; Jakobsen, B; Hecksher, T; Kaminski, K; Dulski, M; Paluch, M; Niss, K

    2015-11-14

    In this paper, we present results of dielectric and shear-mechanical studies for amine (2-ethyl-1-hexylamine) and thiol (2-ethyl-1-hexanethiol) derivatives of the monohydroxy alcohol, 2-ethyl-1-hexanol. The amine and thiol can form hydrogen bonds weaker in strength than those of the alcohol. The combination of dielectric and shear-mechanical data enables us to reveal the presence of a relaxation mode slower than the α-relaxation. This mode is analogous to the Debye mode seen in monohydroxy alcohols and demonstrates that supramolecular structures are present for systems with lower hydrogen bonding strength. We report some key features accompanying the decrease in the strength of the hydrogen bonding interactions on the relaxation dynamics close to the glass-transition. This includes changes (i) in the amplitude of the Debye and α-relaxations and (ii) the separation between primary and secondary modes.

  13. Investigating the complex mechanism of B migration in a magnetic-tunnel-junction trilayer structure—a combined study using XPS and TOF-SIMS

    NASA Astrophysics Data System (ADS)

    Ying, Ji-Feng; Ji, Rong; Ter Lim, Sze; Tran, Michael N.; Wang, Chen Chen; Ernult, Franck

    2016-02-01

    The magnetic-tunnel-junction (MTJ) structure is the core of many important devices, such as magnetic recording head and STT-RAM. CoFeB/MgO/CoFeB tri-layer thin-film stack is a widely researched MTJ structure. In this tri-layer, the functional property of the MTJ, i.e. its TMR ratio, is critically dependent on the crystal orientation of the CoFe grains. In order for the desired (1 0 0) out of plane texture to develop in the CoFeB layers, B needs to be engineered to be expelled out of these CoFeB layers, and diffuse or migrate into the adjacent layers. Ta is usually used as a seed layer adjacent to the MTJ structure. In this work, we investigated the important B-migration mechanisms within this MTJ structure through a combined XPS/TOF-SIMS study. Specifically, we tried to elucidate the possible physical/chemical interactions between the B and Ta that could happen with different film stack designs. Previous works have shown that there might be two possible B-migration mechanisms. One mechanism is direct B diffusion into the adjacent Ta layer during annealing. The other B-migration mechanism is through the formation of TaBOx species, in which B could be carried out by the Ta diffusion. In particular, through studying a series of film stacks, we discussed the circumstances under which one of these B-migration mechanisms becomes dominant. Furthermore, we discussed how these B-migration mechanisms facilitated the B expulsion in a common MTJ structure.

  14. Management of Low Back Pain: A Case Series Illustrating the Pragmatic Combination of Treatment- and Mechanism-Based Classification Systems

    PubMed Central

    Pinto, Daniel; Cleland, Joshua; Palmer, Jessica; Eberhart, Sarah L

    2007-01-01

    This case series describes the pragmatic use of a treatment-based classification system for the management of four patients with a chief complaint of low back pain. Patients were initially classified into stabilization, manipulation, or specific exercise subgroups based on history and clinical examination. Each patient was reassessed during the course of clinical care to determine whether to continue treating according to the initially assigned subgroup or to alter management and incorporate a mechanism-based classification addressing identified impairments. Patient #1 was initially classified in the manipulation category. Within three visits, he reported being “a great deal better” on the Global Rating of Change (GROC) and had a 6-point improvement in his Oswestry Disability Index (ODI). Patient #2, classified in the specific exercise/extension category, reported being “moderately better” using the GROC and had a 22-point improvement in her ODI within six visits. Patient #3, classified in the stabilization category, reported being “a very great deal better” on the GROC and had a 30-point improvement in his ODI Index within four visits. Patient #4 was categorized initially in the manipulation category and subsequently in the specific exercise category; after five visits, he noted being “quite a bit better” using the GROC and he reported a 58-point improvement on his ODI. All four patients in this study were managed using a dynamic pragmatic treatment-based classification approach that allowed for the change of subgroup classification and treatment of impairments and all achieved a clinically meaningful improvement in pain and disability PMID:19066651

  15. Molecular distributions in interphases: statistical mechanical theory combined with molecular dynamics simulation of a model lipid bilayer.

    PubMed Central

    Xiang, T X; Anderson, B D

    1994-01-01

    A mean-field statistical mechanical theory has been developed to describe molecular distributions in interphases. The excluded volume interaction has been modeled in terms of a reversible work that is required to create a cavity of the solute size against a pressure tensor exerted by the surrounding interphase molecules. The free energy change associated with this compression process includes the configuration entropy as well as the change in conformational energy of the surrounding chain molecules. The lateral pressure profile in a model lipid bilayer (30.5 A2/chain molecule) has been calculated as a function of depth in the bilayer interior by molecular dynamics simulation. The lateral pressure has a plateau value of 309 +/- 48 bar in the highly ordered region and decreases abruptly in the center of the bilayer. Model calculations have shown that for solute molecules with ellipsoidal symmetry, the orientational order increases with the ratio of the long to short molecular axes at a given solute volume and increases with solute volume at a given axial ratio, in accordance with recent experimental data. Increased lateral pressure (p perpendicular) results in higher local order and exclusion of solute from the interphase, in parallel with the effect of surface density on the partitioning and local order. The logarithm of the interphase/water partition coefficient for spherical solutes decreases linearly with solute volume. This is also an excellent approximation for elongated solutes because of the relatively weak dependence of solute partitioning on molecular shape. The slope is equal to (2p perpendicular - p parallel)/3KBT, where p parallel is the normal pressure component, and different from that predicted by the mean-field lattice theory. Finally, the lattice theory has been extended herein to incorporate an additional constraint on chain packing in the interphase and to account for the effect of solute size on partitioning. Images FIGURE 1 FIGURE 2 PMID:8011890

  16. Combining the Finite Element Method with Structural Connectome-based Analysis for Modeling Neurotrauma: Connectome Neurotrauma Mechanics

    PubMed Central

    Kraft, Reuben H.; Mckee, Phillip Justin; Dagro, Amy M.; Grafton, Scott T.

    2012-01-01

    This article presents the integration of brain injury biomechanics and graph theoretical analysis of neuronal connections, or connectomics, to form a neurocomputational model that captures spatiotemporal characteristics of trauma. We relate localized mechanical brain damage predicted from biofidelic finite element simulations of the human head subjected to impact with degradation in the structural connectome for a single individual. The finite element model incorporates various length scales into the full head simulations by including anisotropic constitutive laws informed by diffusion tensor imaging. Coupling between the finite element analysis and network-based tools is established through experimentally-based cellular injury thresholds for white matter regions. Once edges are degraded, graph theoretical measures are computed on the “damaged” network. For a frontal impact, the simulations predict that the temporal and occipital regions undergo the most axonal strain and strain rate at short times (less than 24 hrs), which leads to cellular death initiation, which results in damage that shows dependence on angle of impact and underlying microstructure of brain tissue. The monotonic cellular death relationships predict a spatiotemporal change of structural damage. Interestingly, at 96 hrs post-impact, computations predict no network nodes were completely disconnected from the network, despite significant damage to network edges. At early times () network measures of global and local efficiency were degraded little; however, as time increased to 96 hrs the network properties were significantly reduced. In the future, this computational framework could help inform functional networks from physics-based structural brain biomechanics to obtain not only a biomechanics-based understanding of injury, but also neurophysiological insight. PMID:22915997

  17. Mechanisms underlying muscle fatigue differ between multiple sclerosis patients and controls: a combined electrophysiological and neuroimaging study.

    PubMed

    Steens, A; Heersema, D J; Maurits, N M; Renken, R J; Zijdewind, I

    2012-02-15

    Increased sense of fatigue is an important and conspicuous symptom in multiple sclerosis (MS). Muscle fatigue is associated with increased sense of fatigue in MS (Steens et al., 2011). The aim of this study was to investigate mechanisms that can explain muscle fatigue in MS patients and controls. We assessed changes in cortical activation (BOLD), voluntary activation (twitch interpolation) and muscle force during a sustained maximal voluntary contraction (MVC) in twenty MS patients and twenty healthy controls. In control participants, individual differences in force decline (mean 65% MVC, 8 SD) during the sustained maximal contraction could be accounted for by differences in maximal voluntary force (R(2): 0.49, p = 0.001); stronger participants presented a larger force decline. The small decline in voluntary activation (mean 7.8%, 11.8 SD) did not contribute significantly to the force decline. During the sustained contraction, the force decline was accompanied by an increase in cortical activation in the main motor areas. In MS patients, the differences in the decline in force (mean 67% MVC, 9 SD) were significantly associated (R(2): 0.51, p = 0.001) with a decline in voluntary activation (mean 20.1%, 20.6 SD) and not with maximal force or decline in rest twitch. The corresponding cortical activation in motor areas showed an increase in the first two intervals of the sustained contraction but declined during the last interval. Our data indicate that muscle fatigue during a sustained contraction in MS patients is associated with changes in the voluntary activation that are not sufficiently compensated by increased cortical activation. Control participants, however, show increased cortical activation to compensate for these fatigue-related changes in voluntary activation and the major cause of force decline is therefore to be found in the periphery (muscles).

  18. An in vitro and in vivo study on the synergistic effect and mechanism of itraconazole or voriconazole alone and in combination with tetrandrine against Aspergillus fumigatus.

    PubMed

    Li, Shui-Xiu; Song, Yan-Jun; Zhang, Ling-Ling; Shi, Jian-Ping; Ma, Zheng-Lai; Guo, Hui; Dong, Hui-Yu; Li, Yi-Ming; Zhang, Hong

    2015-09-01

    In this study, we investigated the in vitro antifungal effects of itraconazole/voriconazole (ITR/VRC) alone and in combination with tetrandrine (TET) against 23 clinical isolates of A. fumigatus using a chequerboard microdilution method. The dynamic antifungal effects of TET with ITR/VRC against A. fumigatus were assessed in vivo using time-kill curves following systemic infection of mice with A. fumigatus. After treatment, efflux pump activity was determined by the efflux of rhodamine 6G (R6G). When ITR was combined with TET, ITR MICs were reduced from 0.125-32 to 0.0625-2 μg ml(-1), and TET MICs were reduced from 256-512 to 8-64 μg ml(-1). When VRC was combined with TET, VRC MICs were reduced from 0.125-2 to 0.03125-0.5 μg ml(-1), and TET MICs were reduced from 256-512 to 8-256 μg ml(-1). Time-kill curves revealed that A. fumigatus viability was reduced after treatment with ITR/VRC combined with TET versus ITR/VRC alone. ITR/VRC combined with TET significantly prolonged mouse survival and reduced kidney and brain tissue burdens versus ITR/VRC alone (P < 0.05). Moreover, TET inhibited R6G efflux of A. fumigatus. Thus, in vitro and in vivo, TET acted synergistically with ITR/VRC against A. fumigatus, and the synergistic mechanism was related to inhibition of the drug efflux pump. PMID:26296880

  19. Alpha-lipoic acid alone and combined with clozapine reverses schizophrenia-like symptoms induced by ketamine in mice: Participation of antioxidant, nitrergic and neurotrophic mechanisms.

    PubMed

    Vasconcelos, Germana Silva; Ximenes, Naiara Coelho; de Sousa, Caren Nádia Soares; Oliveira, Tatiana de Queiroz; Lima, Laio Ladislau Lopes; de Lucena, David Freitas; Gama, Clarissa Severino; Macêdo, Danielle; Vasconcelos, Silvânia Maria Mendes

    2015-07-01

    Oxidative stress has important implications in schizophrenia. Alpha-lipoic acid (ALA) is a natural antioxidant synthesized in human tissues with clinical uses. We studied the effect of ALA or clozapine (CLZ) alone or in combination in the reversal of schizophrenia-like alterations induced by ketamine (KET). Adult male mice received saline or KET for 14 days. From 8th to 14th days mice were additionally administered saline, ALA (100 mg/kg), CLZ 2.5 or 5 mg/kg or the combinations ALA+CLZ2.5 or ALA+CLZ5. Schizophrenia-like symptoms were evaluated by prepulse inhibition of the startle (PPI) and locomotor activity (positive-like), social preference (negative-like) and Y maze (cognitive-like). Oxidative alterations (reduced glutathione - GSH and lipid peroxidation - LP) and nitrite in the prefrontal cortex (PFC), hippocampus (HC) and striatum (ST) and BDNF in the PFC were also determined. KET caused deficits in PPI, working memory, social interaction and hyperlocomotion. Decreased levels of GSH, nitrite (HC) and BDNF and increased LP were also observed in KET-treated mice. ALA and CLZ alone reversed KET-induced behavioral alterations. These drugs also reversed the decreases in GSH (HC) and BDNF and increase in LP (PFC, HC and ST). The combination ALA+CLZ2.5 reversed behavioral and some neurochemical parameters. However, ALA+CLZ5 caused motor impairment. Therefore, ALA presented an antipsychotic-like profile reversing KET-induced positive- and negative-like symptoms. The mechanism partially involves antioxidant, neurotrophic and nitrergic pathways. The combination of ALA+CLZ2.5 improved most of the parameters evaluated in this study without causing motor impairment demonstrating, thus, that possibly when combined with ALA a lower dose of CLZ is required. PMID:25937462

  20. COMBINED THEORETICAL AND EXPERIMENTAL INVESTIGATION OF MECHANISMS AND KINETICS OF VAPOR-PHASE MERCURY UPTAKE BY CARBONACOUES SURFACES

    SciTech Connect

    Radisav D. Vidic

    2002-05-01

    The first part of this study evaluated the application of a versatile optical technique to study the adsorption and desorption of model adsorbates representative of volatile polar (acetone) and non-polar (propane) organic compounds on a model carbonaceous surface under ultra high vacuum (UHV) conditions. The results showed the strong correlation between optical differential reflectance (ODR) and adsorbate coverage determined by temperature programmed desorption (TPD). ODR technique was proved to be a powerful tool to investigate surface adsorption and desorption from UHV to high pressure conditions. The effects of chemical functionality and surface morphology on the adsorption/desorption behavior of acetone, propane and mercury were investigated for two model carbonaceous surfaces, namely air-cleaved highly oriented pyrolytic graphite (HOPG) and plasma-oxidized HOPG. They can be removed by thermal treatment (> 500 K). The presence of these groups almost completely suppresses propane adsorption at 90K and removal of these groups leads to dramatic increase in adsorption capacity. The amount of acetone adsorbed is independent of surface heat treatment and depends only on total exposure. The effects of morphological heterogeneity is evident for plasma-oxidized HOPG as this substrate provides greater surface area, as well as higher energy binding sites. Mercury adsorption at 100 K on HOPG surfaces with and without chemical functionalities and topological heterogeneity created by plasma oxidation occurs through physisorption. The removal of chemical functionalities from HOPG surface enhances mercury physisorption. Plasma oxidation of HOPG provides additional surface area for mercury adsorption. Mercury adsorption by activated carbon at atmospheric pressure occurs through two distinct mechanisms, physisorption below 348 K and chemisorption above 348 K. No significant impact of oxygen functionalities was observed in the chemisorption region. The key findings of this study

  1. Resolving the mechanism of bacterial inhibition by plant secondary metabolites employing a combination of whole-cell biosensors.

    PubMed

    Chan, Andrea C; Ager, Duane; Thompson, Ian P

    2013-06-01

    Tightening regulations regarding the use of biocides have stimulated interest in investigating alternatives to current antimicrobial strategies. Plant essential oils and their constituent compounds are promising candidates as novel antimicrobial agents because of their excellent ability in killing microbes while being non-toxic to humans at antimicrobially-active concentrations. Allyl isothiocyanate (AIT), carvacrol, cinnamaldehyde (CNAD), citral, and thymol were investigated for their antibacterial activity against Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. The five compounds were screened via disc diffusion assay and broth microdilution method, by which inhibition zone diameters, minimum inhibitory concentrations (MICs), and minimum bactericidal concentrations (MBCs) were determined. AIT and CNAD displayed the greatest inhibitory effects against all species tested, with AIT yielding MICs of 156.25mg/L and MBCs of 156.25 to 312.5mg/L, and CNAD yielding MICs of 78.125 to 156.25mg/L and MBCs of 78.125 to 312.5mg/L. Based on these results, AIT and CNAD were selected for closer examination of their toxic effects. Two complementary bioluminescence-based bacterial biosensors, E. coli HB101_pUCD607_lux and Acinetobacter baylyi ADP1_recA_lux, were employed to examine the dose-response relationships and mechanism of action of AIT and CNAD. This is the first reported study to employ a lux-based biosensor assay coupled with parallel plate count experiments to demonstrate that AIT and CNAD not only damaged cell membranes, but also disrupted cellular metabolism and energy production in bacteria. It is also the first to use genotoxicity-sensing whole-cell bioreporters to demonstrate that neither AIT nor CNAD induced expression of the universal DNA repair gene, recA. This suggests that AIT and CNAD were not genotoxic. As an antimicrobial agent, it is advantageous that the compound be genetically non-damaging so that toxicity towards

  2. Mechanical and chemical processes affecting the chalk during burial, insights from combined reflection seismics, well data and field work

    NASA Astrophysics Data System (ADS)

    Moreau, Julien; Boussaha, Myriam; Nielsen, Lars; Thibault, Nicolas; Stemmerik, Lars

    2014-05-01

    The chalk must undergo several phases of grain reorganisation and chemical reactions during its diagenetic evolution from a carbonaceous ooze to a sedimentary rock. Some of these transformations could be observed on structures from the kilometre- to the micrometre-scale with seismic reflection and cores analyses, respectively. However, few sites allow to combine all the different scale of observation for chalk diagenesis. Onshore and offshore high resolution seismics, two fully cored >350 m wells with wireline logging tools and very high quality exposures from a coastal cliff and a quarry form such an exceptional dataset in the Stevns peninsula area, eastern Danish Basin (Denmark). The studied chalk interval in the area is of Maastrichtian to Danian age. The chalk has been divided in 4 lithofacies, chalk-marl alternations, white chalk, white chalk with flint layers and bryozoan chalk. Advanced stratigraphic works have been performed with astronomical calibration based on stable isotope stratigraphy, wireline logs as well as several palaeontological proxies and detailed sedimentological analysis. Since a couple of decades, a specific kind of fractures has been described in the Chalk of Denmark, the so-called hairline fractures. They have recently been interpreted as compaction bands associated with the pore collapse of the chalk. We have observed these fractures on the field and on the cores in specific intervals. At depth, these fractures are in genetic relation with the formation of some stylolithes. The pressure-solution allows the formation of carbonate seams in the hairline fractures. At larger scale, on the field are observed faults which are sealed with flint precipitations. They slightly offset (<1 m) strata underlined by flint bands. On the onshore and offshore seismic reflection profiles, numerous strata-bound faults form noisy intervals as well as amplitude anomalies. Their normal offsets are less than 25 m. Their branching patterns, and their restriction

  3. Determining the Mechanical Constitutive Properties of Metals as Function of Strain Rate and temperature: A Combined Experimental and Modeling Approach

    SciTech Connect

    Ian Robertson

    2007-04-28

    Development and validation of constitutive models for polycrystalline materials subjected to high strain-rate loading over a range of temperatures are needed to predict the response of engineering materials to in-service type conditions. To account accurately for the complex effects that can occur during extreme and variable loading conditions, requires significant and detailed computational and modeling efforts. These efforts must be integrated fully with precise and targeted experimental measurements that not only verify the predictions of the models, but also provide input about the fundamental processes responsible for the macroscopic response. Achieving this coupling between modeling and experiment is the guiding principle of this program. Specifically, this program seeks to bridge the length scale between discrete dislocation interactions with grain boundaries and continuum models for polycrystalline plasticity. Achieving this goal requires incorporating these complex dislocation-interface interactions into the well-defined behavior of single crystals. Despite the widespread study of metal plasticity, this aspect is not well understood for simple loading conditions, let alone extreme ones. Our experimental approach includes determining the high-strain rate response as a function of strain and temperature with post-mortem characterization of the microstructure, quasi-static testing of pre-deformed material, and direct observation of the dislocation behavior during reloading by using the in situ transmission electron microscope deformation technique. These experiments will provide the basis for development and validation of physically-based constitutive models. One aspect of the program involves the direct observation of specific mechanisms of micro-plasticity, as these indicate the boundary value problem that should be addressed. This focus on the pre-yield region in the quasi-static effort (the elasto-plastic transition) is also a tractable one from an

  4. Study of the mechanism of acetonitrile stacking and its application for directly combining liquid-phase microextraction with micellar electrokinetic chromatography.

    PubMed

    Sun, Jingru; Feng, Jing; Shi, Ludi; Liu, Laping; He, Hui; Fan, Yingying; Hu, Shibin; Liu, Shuhui

    2016-08-26

    Acetonitrile stacking is an online concentration method that is distinctive due to its inclusion of a high proportion of organic solvent in sample matrices. We previously designed a universal methodology for the combination of liquid-phase microextraction (LPME) and capillary electrophoresis (CE) using acetonitrile stacking and micellar electrokinetic chromatography (MEKC) mode, thereby achieving large-volume injection of the diluted LPME extractant and the online concentration. In this report, the methodology was extended to the analysis of highly substituted hydrophobic chlorophenols in wines using diethyl carbonate as the extractant. Additionally, the mechanism of acetonitrile stacking was studied. The results indicated that the combination of LPME and MEKC exhibited good analytical performance: with ∼40-fold concentration by LPME, a 20-cm (33% of the total length) sample plug injection of an eight-fold dilution of diethyl carbonate with the organic solvent-saline solution produced enrichments higher by a factor of 260-791. Limits of qualification ranged from 5.5 to 16.0ng/mL. Acceptable reproducibilities of lower than 1.8% for migration time and 8.6% for peak areas were obtained. A dual stacking mechanism of acetonitrile stacking was revealed, involving transient isotachophoresis plus pH-junction stacking. The latter was associated with a pH shift induced by the presence of acetonitrile. The pseudo-stationary phase (Brij-35) played an important role in reducing the CE running time by weakening the isotachophoretic migration of the analyte ions following Cl(-) ions. The combination of acetonitrile stacking and nonionic micelle-based MEKC appears to be a perfect match for introducing water-immiscible LPME extractants into an aqueous CE system and can thus significantly expand the application of LPME-CE in green analytical chemistry. PMID:27451260

  5. Study of the mechanism of acetonitrile stacking and its application for directly combining liquid-phase microextraction with micellar electrokinetic chromatography.

    PubMed

    Sun, Jingru; Feng, Jing; Shi, Ludi; Liu, Laping; He, Hui; Fan, Yingying; Hu, Shibin; Liu, Shuhui

    2016-08-26

    Acetonitrile stacking is an online concentration method that is distinctive due to its inclusion of a high proportion of organic solvent in sample matrices. We previously designed a universal methodology for the combination of liquid-phase microextraction (LPME) and capillary electrophoresis (CE) using acetonitrile stacking and micellar electrokinetic chromatography (MEKC) mode, thereby achieving large-volume injection of the diluted LPME extractant and the online concentration. In this report, the methodology was extended to the analysis of highly substituted hydrophobic chlorophenols in wines using diethyl carbonate as the extractant. Additionally, the mechanism of acetonitrile stacking was studied. The results indicated that the combination of LPME and MEKC exhibited good analytical performance: with ∼40-fold concentration by LPME, a 20-cm (33% of the total length) sample plug injection of an eight-fold dilution of diethyl carbonate with the organic solvent-saline solution produced enrichments higher by a factor of 260-791. Limits of qualification ranged from 5.5 to 16.0ng/mL. Acceptable reproducibilities of lower than 1.8% for migration time and 8.6% for peak areas were obtained. A dual stacking mechanism of acetonitrile stacking was revealed, involving transient isotachophoresis plus pH-junction stacking. The latter was associated with a pH shift induced by the presence of acetonitrile. The pseudo-stationary phase (Brij-35) played an important role in reducing the CE running time by weakening the isotachophoretic migration of the analyte ions following Cl(-) ions. The combination of acetonitrile stacking and nonionic micelle-based MEKC appears to be a perfect match for introducing water-immiscible LPME extractants into an aqueous CE system and can thus significantly expand the application of LPME-CE in green analytical chemistry.

  6. Mechanisms of large Stokes shift and aggregation-enhanced emission of osmapentalyne cations in solution: combined MD simulations and QM/MM calculations.

    PubMed

    Sun, Guang-Xu; Ju, Ming-Gang; Zang, Hang; Zhao, Yi; Liang, WanZhen

    2015-10-01

    Osmapentalyne cations synthesized recently show remarkable optical properties, such as near-infrared emission, unusual large Stokes shift and aggregation-enhanced emission. Here, the mechanisms behind those novel optical behaviors are revealed from the combined molecular dynamics simulations and hybrid quantum mechanics/molecular mechanics calculations. The results demonstrate that the large Stokes shift in the gas phase comes from a photoexcitation-induced deformation of the osmium plane, whereas in solution it corresponds to the variation of osmium ring symmetry. Although the central chromophore ring dominates the absorption and emission processes, the protecting groups PPh3 join the emission. As osmapentalyne cations are aggregated together in solution, the radical distribution functions of their mass-central distances display several peaks immersed in a broad envelope due to different aggregation pathways. However, the chromophore centers are protected by the PPh3 groups, the aggregation structures do not affect the Stokes shift too much, and the calculated aggregate-enhanced emission is consistent with experimental measurements. PMID:26339695

  7. Combined Pharmacomechanical Thrombolysis of Complete Portomesenteric Thrombosis in a Liver Transplant Recipient

    SciTech Connect

    Lorenz, Jonathan M. Bennett, Shelby; Patel, Jay; Ha, Thuong G. Van; Funaki, Brian

    2013-01-30

    Treatment options for portomesenteric venous thrombosis range from anticoagulation to surgery, depending on chronicity, severity of symptoms, extent of thrombosis, and the availability of local expertise. For acute and subacute cases, a variety of endovascular options have been described in limited published series and case reports, including thrombolysis and mechanical thrombectomy. We report what is to our knowledge the first case in which the Trellis pharmacomechanical thrombolysis device was used successfully to treat complete acute thrombosis of the entire superior mesenteric vein and the entire portal vein with extension into all segmental intrahepatic portal branches in a young adult after liver transplantation. This device, coupled with adjunctive techniques using balloon catheters, facilitated complete restoration of flow, resulting in graft salvage and long-term patency.

  8. Mechanisms that Trigger a Good Health-Care Response to Intimate Partner Violence in Spain. Combining Realist Evaluation and Qualitative Comparative Analysis Approaches

    PubMed Central

    Goicolea, Isabel; Vives-Cases, Carmen; Hurtig, Anna-Karin; Marchal, Bruno; Briones-Vozmediano, Erica; Otero-García, Laura; García-Quinto, Marta; San Sebastian, Miguel

    2015-01-01

    Background Health care professionals, especially those working in primary health-care services, can play a key role in preventing and responding to intimate partner violence. However, there are huge variations in the way health care professionals and primary health care teams respond to intimate partner violence. In this study we tested a previously developed programme theory on 15 primary health care center teams located in four different Spanish regions: Murcia, C Valenciana, Castilla-León and Cantabria. The aim was to identify the key combinations of contextual factors and mechanisms that trigger a good primary health care center team response to intimate partner violence. Methods A multiple case-study design was used. Qualitative and quantitative information was collected from each of the 15 centers (cases). In order to handle the large amount of information without losing familiarity with each case, qualitative comparative analysis was undertaken. Conditions (context and mechanisms) and outcomes, were identified and assessed for each of the 15 cases, and solution formulae were calculated using qualitative comparative analysis software. Results The emerging programme theory highlighted the importance of the combination of each team’s self-efficacy, perceived preparation and women-centredness in generating a good team response to intimate partner violence. The use of the protocol and accumulated experience in primary health care were the most relevant contextual/intervention conditions to trigger a good response. However in order to achieve this, they must be combined with other conditions, such as an enabling team climate, having a champion social worker and having staff with training in intimate partner violence. Conclusions Interventions to improve primary health care teams’ response to intimate partner violence should focus on strengthening team’s self-efficacy, perceived preparation and the implementation of a woman-centred approach. The use of the

  9. Combinations Therapies.

    PubMed

    Reinmuth, Niels; Reck, Martin

    2015-01-01

    Immunotherapy of cancer encompasses different strategies that elicit or enhance the immune response against tumors. The first results from clinical studies have provided promising data for the treatment of lung cancer patients with immunomodulating monotherapies. To improve the potential benefit of cancer immunotherapy, synergistic combinations of the various immunotherapy approaches or of different elements within each of the immunotherapy approaches are being explored. The rationale typically involves different but complementary mechanisms of action, eventually impinging on more than one immune system mechanism. As a prominent example, the simultaneous blockade of PD-1 and CTLA-4 is giving rise to therapeutic synergy, while still offering room for efficacy improvement. Moreover, combinations of immunomodulating agents with chemotherapy or targeted molecules are being tested. Animal models suggest that immunotherapies in combination with these various options offer evidence for synergistic effects and are likely to radically change cancer treatment paradigms. However, data obtained so far indicate that toxic side effects are also potentiated, which may even restrict the selection of patients that are suitable for these combinational approaches. Advancing the field of combinatorial immunotherapy will require changes in the way investigational agents are clinically developed as well as novel experimental end-points for efficacy evaluation. However, this combined therapeutic manipulation of both tumor and stromal cells may lead to a dramatic change in the therapeutic options of lung cancer patients in any disease stage that can only grossly be appreciated by the current studies. PMID:26384009

  10. Combined effects of moisture, temperature, fiber architecture, and sustained load on the mechanical and microstructural properties of notched and unnotched e-glass/vinyl ester composite materials

    NASA Astrophysics Data System (ADS)

    Buck, Stephanie E.

    Structural composite materials are being investigated for use in applications which will require long-term durability in the presence of various environments and external loading conditions. Flaws may be created in these composite materials during manufacturing, machining, or use. Adverse use conditions may result in significantly reduced mechanical properties and changes in the microstructural properties and damage mechanisms of composites with seemingly minor flaws. E-glass/vinyl ester composite coupons, some with a preexisting flaw, have been conditioned in a wet environment for periods of up to nearly 8000 hours at several temperatures, mostly with a sustained tensile load, to determine the changes in the mechanical properties and damage mechanisms which occur with the introduction of a flaw. The fiber architectures used for the unnotched coupons were [0/90/+/-45]2s, [0/90/+/-45]3s, and [90/0]2s, all containing a chopped strand mat in each set, while those used for the notched coupons were [90/0]2s, [0] 16, [0/90]8, and [0/90]f8, with only the first containing the random mat. The combination of moisture and temperature was found to degrade the mechanical properties of the unnotched materials, particularly the tensile strength. The addition of a sustained load was found to further degrade these properties. During conditioning, the damage mechanisms were found to change from matrix microcracking, fiber damage, and occasional edge delaminations for unnotched specimens to the growth of a significant transverse crack from the notch tip and longitudinal tow debonding for notched specimens. Moisture and elevated temperature were found to affect the extent of damage, but not the dual nature of damage, in the vicinity of the notch tip, while the fiber architecture affected some of the patterns of damage. The unidirectional samples, not loaded during conditioning, were tested in load cycles to determine the strain energy release rates for increments of growth of

  11. PD-L1 (B7-H1) and PD-1 Pathway Blockade for Cancer Therapy: Mechanisms, Response Biomarkers and Combinations

    PubMed Central

    Zou, Weiping; Wolchok, Jedd D.; Chen, Lieping

    2016-01-01

    PD-L1 and PD-1 (PD) pathway blockade is a highly promising therapy and has elicited durable anti-tumor responses and long-term remissions in a subset of patients with a broad spectrum of cancers. How to improve, widen, and predict the clinical response to anti-PD therapy is a central theme in the field of cancer immunology and immunotherapy. Oncologic, immunologic, genetic and biological studies focused on the human cancer microenvironment have yielded significant insight into this issue. In this Review, we focus on tumor microenvironment; evaluate several potential therapeutic response markers including the PD-L1 and PD-1 expression pattern, genetic mutations within cancer cells and neoantigens, cancer epigenetics and effector T cell landscape, microbiota, and their mechanisms of action and roles in shaping, being shaped and/or predicting therapeutic responses. We also discuss a variety of combinations with PD pathway blockade and their scientific rationales for cancer treatment. PMID:26936508

  12. [Investigating mechanism of toxicity reduction by combination of Glycyrrhizae Radix et Rhizoma and Aconiti Lateralis Radix Preparata on terms of proteins self-assembly].

    PubMed

    Li, Bing-jie; Shen, Yong; Liao, Ri-tao; Gao, Guan-zhen; Ke, Li-jing; Zhou, Jian-wu; Rao, Ping-fan

    2015-02-01

    The combination of Glycyrrhizae Radix et Rhizoma and Aconiti Lateralis Radix Preparata can increase efficacy and decrease toxicity. This study started from the phenomena of protein self-assembly in the mixed decoction of Glycyrrhizae Radix et Rhizoma with Aconiti Lateralis Radix Preparata. The attenuated mechanism was explored between the combination of Glycyrrhizae Radix et Rhizoma and Aconiti Lateralis Radix Preparata by using the protein of Glycyrrhizae Radix et Rhizoma and aconitine which was the major toxic component of Aconiti Lateralis Radix Preparata. Glycyrrhizae Radix et Rhizoma protein with aconitine could form stable particles which particle mean diameter was (206.2 ± 2.02) nm and (238.20 ± 1.23) nm at pH 5.0 in normal temperature. Through the mouse acute toxicity experiment found that injection of aconitine monomer all mice were killed, and injection of Glycyrrhizae Radix et Rhizoma protein-aconitine particles with the same content of aconitine all mice survived. Survey the stability of Glycyrrhizae Radix et Rhizoma protein-aconitine shows that the colloid particles is stable at room temperature, and it has the possibility to candidate drug carrier. Glycyrrhizae Radix et Rhizoma protein can reduce the toxicity of aconitine through self-assembly.

  13. Atomic-scale and pit-free flattening of GaN by combination of plasma pretreatment and time-controlled chemical mechanical polishing

    SciTech Connect

    Deng, Hui; Endo, Katsuyoshi; Yamamura, Kazuya

    2015-08-03

    Chemical mechanical polishing (CMP) combined with atmospheric-pressure plasma pretreatment was applied to a GaN (0001) substrate. The irradiation of a CF{sub 4}-containing plasma was proven to be very useful for modifying the surface of GaN. When CMP was conducted on a plasma-irradiated surface, a modified layer of GaF{sub 3} acted as a protective layer on GaN by preventing the formation of etch pits. Within a short duration (8 min) of CMP using a commercially available CeO{sub 2} slurry, an atomically flat surface with a root mean square (rms) roughness of 0.11 nm was obtained. Moreover, etch pits, which are inevitably introduced in conventional CMP, could not be observed at the dislocation sites on the polished GaN surface. It was revealed that CMP combined with the plasma pretreatment was very effective for obtaining a pit-free and atomically flat GaN surface.

  14. Enhancing anaerobic digestion of waste activated sludge by the combined use of NaOH and Mg(OH)2: Performance evaluation and mechanism study.

    PubMed

    Huang, Cheng; Lai, Jia; Sun, Xiuyun; Li, Jiansheng; Shen, Jinyou; Han, Weiqing; Wang, Lianjun

    2016-11-01

    In this study, the combination treatment of NaOH and Mg(OH)2 was applied to anaerobic digestion of waste activated sludge (WAS) for simultaneously enhancement of volatile fatty acids (VFAs) production, nutrients removal and sludge dewaterability. The maximum VFAs production (461mg COD/g VSS) was obtained at the NaOH/Mg(OH)2 ratio of 75:25, which was much higher than that of the blank or sole NaOH. Moreover, nutrients removal and sludge dewaterability were improved by the combined using of NaOH and Mg(OH)2. Mechanism investigations revealed that the presence of Mg(OH)2 could maintain alkaline environment, which contributed to inhibit the activity of methanogens. Also, the bridging between Mg(2+) and extracellular polymeric substances (EPS) plays an important role in the solubilization and dewatering of sludge. High-throughput sequencing analysis demonstrated that the abundance of bacteria involved in sludge hydrolysis and VFAs accumulation was greatly enriched with the mixtures of NaOH and Mg(OH)2. PMID:27619711

  15. The combined effects of BDE47 and BaP on oxidatively generated DNA damage in L02 cells and the possible molecular mechanism.

    PubMed

    An, Jing; Yin, Lingling; Shang, Yu; Zhong, Yufang; Zhang, Xinyu; Wu, Minghong; Yu, Zhiqiang; Sheng, Guoying; Fu, Jiamo; Huang, Yuecheng

    2011-04-01

    Polybrominated diphenyl ethers (PBDEs) and polycyclic aromatic hydrocarbons (PAHs) coexist widely in the environment and have generated adverse effects on the environment and human health. The purpose of this study was to investigate the combined toxic effects of these chemicals and the related mechanism. L02 cells were exposed to BDE47 (5, 10μmol/L) or/and BaP (50μmol/L) in different administration order. The cell growth and survival, DNA strand breaks, oxidative stress index (ROS, SOD, GSH, and MDA), LDH release and the expression level of CYP1 family members were measured. The result showed that BDE47 or/and BaP had no effect on the cell growth and survival under the present conditions. However, compared with the groups treated with BDE47 or BaP alone, the combined-treated groups induced significantly elevated DNA strand breaks, ROS production, and MDA level. Especially, pretreatment with BDE47 followed by BaP led to the strongest effects. Addition of the antioxidant N-acetyl-l-cysteine (NAC) markedly reduced the ROS level and partly suppressed the DNA strand breaks induced by BDE47 or/and BaP. Meanwhile, the combined treatment groups also markedly increased the SOD activity, GSH content, and LDH release level compared with the control group. The real-time PCR results showed that BaP could significantly induce the expression of CYP1A1 and CYP1B1, however, the pre-treatment with BDE47 appeared to attenuate the BaP-induced CYP1 expression. All of above findings indicated that BDE47 and BaP had a synergistic effect on oxidatively generated DNA damage in L02 cells via regulation on the oxidative stress response and the expression of CYP1 metabolism enzymes.

  16. Virtual screening of LPXTG competitive SrtA inhibitors targeting signal transduction mechanism in Bacillus anthracis: a combined experimental and theoretical study.

    PubMed

    Selvaraj, Chandrabose; Sivakamavalli, Jeyachandran; Baskaralingam, Vaseeharan; Singh, Sanjeev Kumar

    2014-06-01

    Members of the sortase enzyme super family decorate the surfaces of Bacillus anthracis cell wall with proteins that play key roles in microbial pathogenesis and its biofilm formation. Bacillus anthracis Sortase-A (Ba-SrtA) is a potential target for new therapeutics as it is required for B. anthracis survival and replication within macrophages. An understanding of the binding site pocket and substrate recognition mechanism by SrtA enzymes may serve to be beneficial in the rational development of sortase inhibitors. Here, the LPXTG signal peptide-based competitive inhibitors are screened against the Ba-SrtA and compounds with reasonable inhibition, specificity, and mechanisms of inactivation of SrtA have been covered. The screened compounds are experimentally validated against the phylogenetically similar Gram-positive pathogen B. cereus. In situ microscopic visualizations suggest that these screened compounds showed the microbial and biofilm inhibitory activity against B. cereus. It facilitates the further development of these molecules into useful anti-infective agents to treat infections caused by B. anthracis and other Gram-positive pathogens. These results provide insight into basic design principles for generating new clinically relevant lead molecules. It also provides an alternative strategy where a screened ligand molecule can be used in combination to battle increasingly against the Gram-positive pathogens.

  17. Reduction in adipose tissue volume using a new high-power radiofrequency technology combined with infrared light and mechanical manipulation for body contouring.

    PubMed

    Adatto, Maurice A; Adatto-Neilson, Robyn M; Morren, Grietje

    2014-09-01

    them were satisfied with the results at the follow-up visit. The application of high-power RF energy combined with infrared (IR), mechanical massage, and vacuum appears to be an effective modality for the reduction in circumferences of the abdomen/flank, buttock and thigh regions, and the improvement of skin appearance. The present study performed with a new device suggests that the underlying mechanism of action is reduction in the subcutaneous adipose tissue volume and intensification of dermal matrix density.

  18. Stepwise Catalytic Mechanism via Short-Lived Intermediate Inferred from Combined QM/MM MERP and PES Calculations on Retaining Glycosyltransferase ppGalNAcT2

    PubMed Central

    Trnka, Tomáš; Kozmon, Stanislav; Tvaroška, Igor; Koča, Jaroslav

    2015-01-01

    The glycosylation of cell surface proteins plays a crucial role in a multitude of biological processes, such as cell adhesion and recognition. To understand the process of protein glycosylation, the reaction mechanisms of the participating enzymes need to be known. However, the reaction mechanism of retaining glycosyltransferases has not yet been sufficiently explained. Here we investigated the catalytic mechanism of human isoform 2 of the retaining glycosyltransferase polypeptide UDP-GalNAc transferase by coupling two different QM/MM-based approaches, namely a potential energy surface scan in two distance difference dimensions and a minimum energy reaction path optimisation using the Nudged Elastic Band method. Potential energy scan studies often suffer from inadequate sampling of reactive processes due to a predefined scan coordinate system. At the same time, path optimisation methods enable the sampling of a virtually unlimited number of dimensions, but their results cannot be unambiguously interpreted without knowledge of the potential energy surface. By combining these methods, we have been able to eliminate the most significant sources of potential errors inherent to each of these approaches. The structural model is based on the crystal structure of human isoform 2. In the QM/MM method, the QM region consists of 275 atoms, the remaining 5776 atoms were in the MM region. We found that ppGalNAcT2 catalyzes a same-face nucleophilic substitution with internal return (SNi). The optimized transition state for the reaction is 13.8 kcal/mol higher in energy than the reactant while the energy of the product complex is 6.7 kcal/mol lower. During the process of nucleophilic attack, a proton is synchronously transferred to the leaving phosphate. The presence of a short-lived metastable oxocarbenium intermediate is likely, as indicated by the reaction energy profiles obtained using high-level density functionals. PMID:25849117

  19. Stepwise catalytic mechanism via short-lived intermediate inferred from combined QM/MM MERP and PES calculations on retaining glycosyltransferase ppGalNAcT2.

    PubMed

    Trnka, Tomáš; Kozmon, Stanislav; Tvaroška, Igor; Koča, Jaroslav

    2015-04-01

    The glycosylation of cell surface proteins plays a crucial role in a multitude of biological processes, such as cell adhesion and recognition. To understand the process of protein glycosylation, the reaction mechanisms of the participating enzymes need to be known. However, the reaction mechanism of retaining glycosyltransferases has not yet been sufficiently explained. Here we investigated the catalytic mechanism of human isoform 2 of the retaining glycosyltransferase polypeptide UDP-GalNAc transferase by coupling two different QM/MM-based approaches, namely a potential energy surface scan in two distance difference dimensions and a minimum energy reaction path optimisation using the Nudged Elastic Band method. Potential energy scan studies often suffer from inadequate sampling of reactive processes due to a predefined scan coordinate system. At the same time, path optimisation methods enable the sampling of a virtually unlimited number of dimensions, but their results cannot be unambiguously interpreted without knowledge of the potential energy surface. By combining these methods, we have been able to eliminate the most significant sources of potential errors inherent to each of these approaches. The structural model is based on the crystal structure of human isoform 2. In the QM/MM method, the QM region consists of 275 atoms, the remaining 5776 atoms were in the MM region. We found that ppGalNAcT2 catalyzes a same-face nucleophilic substitution with internal return (SNi). The optimized transition state for the reaction is 13.8 kcal/mol higher in energy than the reactant while the energy of the product complex is 6.7 kcal/mol lower. During the process of nucleophilic attack, a proton is synchronously transferred to the leaving phosphate. The presence of a short-lived metastable oxocarbenium intermediate is likely, as indicated by the reaction energy profiles obtained using high-level density functionals.

  20. Elucidating the degradation mechanism of the cathode catalyst of PEFCs by a combination of electrochemical methods and X-ray fluorescence spectroscopy.

    PubMed

    Monzó, J; van der Vliet, D F; Yanson, A; Rodriguez, P

    2016-08-10

    In this study, we report a methodology which enables the determination of the degradation mechanisms responsible for catalyst deterioration under different accelerated stress protocols (ASPs) by combining measurements of the electrochemical surface area (ECSA) and Pt content (by X-ray fluorescence). The validation of this method was assessed on high surface area unsupported Pt nanoparticles (Pt-NPs), Pt nanoparticles supported on TaC (Pt/TaC) and Pt nanoparticles supported on Vulcan carbon (Pt/Vulcan). In the load cycle protocol, the degradation of Pt-NPs and Pt/Vulcan follows associative processes (e.g. agglomeration) in the first 2000 cycles, however, in successive cycles the degradation goes through dissociative processes such as Pt dissolution, as is evident from a similar decay of ECSA and Pt content. In contrast, the degradation mechanism for Pt nanoparticles dispersed on TaC occurs continuously through the dissociative processes (e.g. Pt dissolution or particle detachment), with similar decay rates of both Pt content and ECSA. In the start-up/shut-down protocol, high surface area Pt-NPs follow associative processes (e.g. Ostwald ripening) in the first 4000 cycles, after which the degradation continues through dissociative processes. On the other hand, dissociative mechanisms always govern the degradation of Pt/TaC under start-up/shut-down protocol conditions. Finally, we report that Pt nanoparticles supported on TaC exhibit the highest catalytic activity and long term durability of the three nanoparticle systems tested. This makes Pt/TaC a potentially valuable catalyst system for application in polymer electrolyte fuel cell cathodes. PMID:27464340

  1. An application of the novel quantum mechanical/molecular mechanical method combined with the theory of energy representation: An ionic dissociation of a water molecule in the supercritical water.

    PubMed

    Takahashi, Hideaki; Satou, Wataru; Hori, Takumi; Nitta, Tomoshige

    2005-01-22

    A novel quantum chemical approach recently developed has been applied to an ionic dissociation of a water molecule (2H(2)O-->H(3)O(+)+OH(-)) in ambient and supercritical water. The method is based on the quantum mechanical/molecular mechanical (QM/MM) simulations combined with the theory of energy representation (QM/MM-ER), where the energy distribution function of MM solvent molecules around a QM solute serves as a fundamental variable to determine the hydration free energy of the solute according to the rigorous framework of the theory of energy representation. The density dependence of the dissociation free energy in the supercritical water has been investigated for the density range from 0.1 to 0.6 g/cm(3) with the temperature fixed at a constant. It has been found that the product ionic species significantly stabilizes in the high density region as compared with the low density. Consequently, the dissociation free energy decreases monotonically as the density increases. The decomposition of the hydration free energy has revealed that the entropic term (-TDeltaS) strongly depends on the density of the solution and dominates the behavior of the dissociation free energy with respect to the variation of the density. The increase in the entropic term in the low density region can be attributed to the decrease in the translational degrees of freedom brought about by the aggregation of solvent water molecules around the ionic solute.

  2. COMBINES AND COMBINING.

    ERIC Educational Resources Information Center

    RIDENOUR, HARLAN E.

    THROUGH THE USE OF THIS MANUAL, VOCATIONAL AGRICULTURE STUDENTS WITH OCCUPATIONAL INTEREST IN GRAIN FARMING AND CUSTOM COMBINE OPERATION MAY GAIN KNOWLEDGE ABOUT THE BASIC DESIGN AND OPERATION OF COMBINES. DEVELOPMENT BY A STATE CURRICULUM MATERIALS DIRECTOR INCLUDED CONSULTATION WITH ENGINEERS, TRIAL, AND REVISION. OBJECTIVES ARE STATED IN TERMS…

  3. Development of Combined Dry Heat and Chlorine Dioxide Gas Treatment with Mechanical Mixing for Inactivation of Salmonella enterica Serovar Montevideo on Mung Bean Seeds.

    PubMed

    Annous, Bassam A; Burke, Angela

    2015-05-01

    Foodborne outbreaks have been associated with the consumption of fresh sprouted beans. The sprouting conditions of mung bean seeds provide optimal conditions of temperature and relative humidity for any potential pathogenic contaminant on the seeds to grow. The lack of a kill step postsprouting is a major safety concern. Thus, the use of a kill step on the seeds prior to a sprouting step would enhance the safety of fresh sprouts. The objective of this work was to evaluate the effectiveness of the combined thermal and chlorine dioxide gas (3.5 mg/liter of air) treatment with mechanical mixing (tumbling) to eliminate Salmonella on artificially inoculated mung bean seeds. Although no viable Salmonella was recovered from seeds treated in hot water at 60°C for 2 h, these treated seeds failed to germinate. Dry heat treatments (55, 60, or 70°C) for up to 8 h reduced Salmonella populations in excess of 3 log CFU/g. The use of tumbling, while treating the seeds, resulted in up to 1.6 log CFU/g reduction in Salmonella populations compared with no tumbling. Dry heat treatment at 65°C for 18 h with tumbling resulted in a complete inactivation of Salmonella populations on inoculated seeds with low inoculum levels (2.83 log CFU/g) as compared with high inoculum levels (4.75 log CFU/g). The increased reductions in pathogenic populations on the seeds with the use of tumbling could be attributed to increased uniformity of heat transfer and exposure to chlorine dioxide gas. All treated seeds were capable of germinating, as well as the nontreated controls. These results suggest that this combined treatment would be a viable process for enhancing the safety of fresh sprouts. PMID:25951379

  4. Alterations in glucocorticoid negative feedback following maternal Pb, prenatal stress and the combination: A potential biological unifying mechanism for their corresponding disease profiles

    SciTech Connect

    Rossi-George, A.; Virgolini, M.B.; Weston, D.; Cory-Slechta, D.A.

    2009-01-01

    Combined exposures to maternal lead (Pb) and prenatal stress (PS) can act synergistically to enhance behavioral and neurochemical toxicity in offspring. Maternal Pb itself causes permanent dysfunction of the body's major stress system, the hypothalamic pituitary adrenal (HPA) axis. The current study sought to determine the potential involvement of altered negative glucocorticoid feedback as a mechanistic basis of the effects in rats of maternal Pb (0, 50 or 150 ppm in drinking water beginning 2 mo prior to breeding), prenatal stress (PS; restraint on gestational days 16-17) and combined maternal Pb + PS in 8 mo old male and female offspring. Corticosterone changes were measured over 24 h following an i.p. injection stress containing vehicle or 100 or 300 {mu}g/kg (females) or 100 or 150 {mu}g/kg (males) dexamethasone (DEX). Both Pb and PS prolonged the time course of corticosterone reduction following vehicle injection stress. Pb effects were non-monotonic, with a greater impact at 50 vs. 150 ppm, particularly in males, where further enhancement occurred with PS. In accord with these findings, the efficacy of DEX in suppressing corticosterone was reduced by Pb and Pb + PS in both genders, with Pb efficacy enhanced by PS in females, over the first 6 h post-administration. A marked prolongation of DEX effects was found in males. Thus, Pb, PS and Pb + PS, sometimes additively, produced hypercortisolism in both genders, followed by hypocortisolism in males, consistent with HPA axis dysfunction. These findings may provide a plausible unifying biological mechanism for the reported links between Pb exposure and stress-associated diseases and disorders mediated via the HPA axis, including obesity, hypertension, diabetes, anxiety, schizophrenia and depression. They also suggest broadening of Pb screening programs to pregnant women in high stress environments.

  5. Development of Combined Dry Heat and Chlorine Dioxide Gas Treatment with Mechanical Mixing for Inactivation of Salmonella enterica Serovar Montevideo on Mung Bean Seeds.

    PubMed

    Annous, Bassam A; Burke, Angela

    2015-05-01

    Foodborne outbreaks have been associated with the consumption of fresh sprouted beans. The sprouting conditions of mung bean seeds provide optimal conditions of temperature and relative humidity for any potential pathogenic contaminant on the seeds to grow. The lack of a kill step postsprouting is a major safety concern. Thus, the use of a kill step on the seeds prior to a sprouting step would enhance the safety of fresh sprouts. The objective of this work was to evaluate the effectiveness of the combined thermal and chlorine dioxide gas (3.5 mg/liter of air) treatment with mechanical mixing (tumbling) to eliminate Salmonella on artificially inoculated mung bean seeds. Although no viable Salmonella was recovered from seeds treated in hot water at 60°C for 2 h, these treated seeds failed to germinate. Dry heat treatments (55, 60, or 70°C) for up to 8 h reduced Salmonella populations in excess of 3 log CFU/g. The use of tumbling, while treating the seeds, resulted in up to 1.6 log CFU/g reduction in Salmonella populations compared with no tumbling. Dry heat treatment at 65°C for 18 h with tumbling resulted in a complete inactivation of Salmonella populations on inoculated seeds with low inoculum levels (2.83 log CFU/g) as compared with high inoculum levels (4.75 log CFU/g). The increased reductions in pathogenic populations on the seeds with the use of tumbling could be attributed to increased uniformity of heat transfer and exposure to chlorine dioxide gas. All treated seeds were capable of germinating, as well as the nontreated controls. These results suggest that this combined treatment would be a viable process for enhancing the safety of fresh sprouts.

  6. Insights into the mechanisms underlying mercury-induced oxidative stress in gills of wild fish (Liza aurata) combining (1)H NMR metabolomics and conventional biochemical assays.

    PubMed

    Cappello, Tiziana; Brandão, Fátima; Guilherme, Sofia; Santos, Maria Ana; Maisano, Maria; Mauceri, Angela; Canário, João; Pacheco, Mário; Pereira, Patrícia

    2016-04-01

    Oxidative stress has been described as a key pathway to initiate mercury (Hg) toxicity in fish. However, the mechanisms underlying Hg-induced oxidative stress in fish still need to be clarified. To this aim, environmental metabolomics in combination with a battery of conventional oxidative stress biomarkers were applied to the gills of golden grey mullet (Liza aurata) collected from Largo do Laranjo (LAR), a confined Hg contaminated area, and São Jacinto (SJ), selected as reference site (Aveiro Lagoon, Portugal). Higher accumulation of inorganic Hg and methylmercury was found in gills of fish from LAR relative to SJ. Nuclear magnetic resonance (NMR)-based metabolomics revealed changes in metabolites related to antioxidant protection, namely depletion of reduced glutathione (GSH) and its constituent amino acids, glutamate and glycine. The interference of Hg with the antioxidant protection of gills was corroborated through oxidative stress endpoints, namely the depletion of glutathione peroxidase and superoxide dismutase activities at LAR. The increase of total glutathione content (reduced glutathione+oxidized glutathione) at LAR, in parallel with GSH depletion aforementioned, indicates the occurrence of massive GSH oxidation under Hg stress, and an inability to carry out its regeneration (glutathione reductase activity was unaltered) or de novo synthesis. Nevertheless, the results suggest the occurrence of alternative mechanisms for preventing lipid peroxidative damage, which may be associated with the enhancement of membrane stabilization/repair processes resulting from depletion in the precursors of phosphatidylcholine (phosphocholine and glycerophosphocholine), as highlighted by NMR spectroscopy. However, the observed decrease in taurine may be attributable to alterations in the structure of cell membranes or interference in osmoregulatory processes. Overall, the novel concurrent use of metabolomics and conventional oxidative stress endpoints demonstrated to be

  7. Understanding the adsorption of CuPc and ZnPc on noble metal surfaces by combining quantum-mechanical modelling and photoelectron spectroscopy.

    PubMed

    Huang, Yu Li; Wruss, Elisabeth; Egger, David A; Kera, Satoshi; Ueno, Nobuo; Saidi, Wissam A; Bucko, Tomas; Wee, Andrew T S; Zojer, Egbert

    2014-03-07

    Phthalocyanines are an important class of organic semiconductors and, thus, their interfaces with metals are both of fundamental and practical relevance. In the present contribution we provide a combined theoretical and experimental study, in which we show that state-of-the-art quantum-mechanical simulations are nowadays capable of treating most properties of such interfaces in a quantitatively reliable manner. This is shown for Cu-phthalocyanine (CuPc) and Zn-phthalocyanine (ZnPc) on Au(111) and Ag(111) surfaces. Using a recently developed approach for efficiently treating van der Waals (vdW) interactions at metal/organic interfaces, we calculate adsorption geometries in excellent agreement with experiments. With these geometries available, we are then able to accurately describe the interfacial electronic structure arising from molecular adsorption. We find that bonding is dominated by vdW forces for all studied interfaces. Concomitantly, charge rearrangements on Au(111) are exclusively due to Pauli pushback. On Ag(111), we additionally observe charge transfer from the metal to one of the spin-channels associated with the lowest unoccupied π-states of the molecules. Comparing the interfacial density of states with our ultraviolet photoelectron spectroscopy (UPS) experiments, we find that the use of a hybrid functionals is necessary to obtain the correct order of the electronic states.

  8. Effect of Combined Addition of Cu and Aluminum Oxide Nanoparticles on Mechanical Properties and Microstructure of Al-7Si-0.3Mg Alloy

    NASA Astrophysics Data System (ADS)

    Choi, Hongseok; Jones, Milton; Konishi, Hiromi; Li, Xiaochun

    2012-02-01

    In this study, an ultrasonic cavitation based dispersion technique was used to fabricate Al-7Si-0.3Mg alloyed with Cu and reinforced with 1 wt pct Al2O3 nanoparticles, in order to investigate their influence on the mechanical properties and microstructures of Al-7Si-0.3Mg alloy. The combined addition of 0.5 pct Cu with 1 pct Al2O3 nanoparticles increased the yield strength, tensile strength, and ductility of the as-cast Al-7Si-0.3Mg alloy, mostly due to grain refinement and modification of the eutectic Si and θ-CuAl2 phases. Moreover, Al-7Si-0.3Mg-0.5Cu-1 pct Al2O3 nanocomposites after T6 heat treatment showed a significant enhancement of ductility (increased by 512 pct) and tensile strength (by 22 pct). The significant enhancement of properties is attributed to the suppression of pore formation and modification of eutectic Si phases due to the addition of Al2O3 nanoparticles. However, the yield strength of the T6 heat-treated nanocomposites was limited in enhancement due to a reaction between Mg and Al2O3 nanoparticles.

  9. Understanding the adsorption of CuPc and ZnPc on noble metal surfaces by combining quantum-mechanical modelling and photoelectron spectroscopy.

    PubMed

    Huang, Yu Li; Wruss, Elisabeth; Egger, David A; Kera, Satoshi; Ueno, Nobuo; Saidi, Wissam A; Bucko, Tomas; Wee, Andrew T S; Zojer, Egbert

    2014-01-01

    Phthalocyanines are an important class of organic semiconductors and, thus, their interfaces with metals are both of fundamental and practical relevance. In the present contribution we provide a combined theoretical and experimental study, in which we show that state-of-the-art quantum-mechanical simulations are nowadays capable of treating most properties of such interfaces in a quantitatively reliable manner. This is shown for Cu-phthalocyanine (CuPc) and Zn-phthalocyanine (ZnPc) on Au(111) and Ag(111) surfaces. Using a recently developed approach for efficiently treating van der Waals (vdW) interactions at metal/organic interfaces, we calculate adsorption geometries in excellent agreement with experiments. With these geometries available, we are then able to accurately describe the interfacial electronic structure arising from molecular adsorption. We find that bonding is dominated by vdW forces for all studied interfaces. Concomitantly, charge rearrangements on Au(111) are exclusively due to Pauli pushback. On Ag(111), we additionally observe charge transfer from the metal to one of the spin-channels associated with the lowest unoccupied π-states of the molecules. Comparing the interfacial density of states with our ultraviolet photoelectron spectroscopy (UPS) experiments, we find that the use of a hybrid functionals is necessary to obtain the correct order of the electronic states. PMID:24609018

  10. Toward the complete utilization of rice straw: Methane fermentation and lignin recovery by a combinational process involving mechanical milling, supporting material and nanofiltration.

    PubMed

    Sasaki, Kengo; Okamoto, Mami; Shirai, Tomokazu; Tsuge, Yota; Fujino, Ayami; Sasaki, Daisuke; Morita, Masahiko; Matsuda, Fumio; Kikuchi, Jun; Kondo, Akihiko

    2016-09-01

    Rice straw was mechanically milled using a process consuming 1.9MJ/kg-biomass, and 10g/L of unmilled or milled rice straw was used as the carbon source for methane fermentation in a digester containing carbon fiber textile as the supporting material. Milling increased methane production from 226 to 419mL/L/day at an organic loading rate of 2180mg-dichromate chemical oxygen demand/L/day, corresponding to 260mLCH4/gVS. Storage of the fermentation effluent at room temperature decreased the weight of the milled rice straw residue from 3.81 to 1.00g/L. The supernatant of the effluent was subjected to nanofiltration. The black concentrates deposited on the nanofiltration membranes contained 53.0-57.9% lignin. Solution nuclear magnetic resonance showed that lignin aromatic components such as p-hydroxyphenyl (H), guaiacyl (G), and syringyl (S) were retained primarily, and major lignin interunit structures such as the β-O-4-H/G unit were absent. This combinational process will aid the complete utilization of rice straw. PMID:27318161

  11. PD-L1 (B7-H1) and PD-1 pathway blockade for cancer therapy: Mechanisms, response biomarkers, and combinations.

    PubMed

    Zou, Weiping; Wolchok, Jedd D; Chen, Lieping

    2016-03-01

    PD-L1 and PD-1 (PD) pathway blockade is a highly promising therapy and has elicited durable antitumor responses and long-term remissions in a subset of patients with a broad spectrum of cancers. How to improve, widen, and predict the clinical response to anti-PD therapy is a central theme in the field of cancer immunology and immunotherapy. Oncologic, immunologic, genetic, and biological studies focused on the human cancer microenvironment have yielded substantial insight into this issue. Here, we focus on tumor microenvironment and evaluate several potential therapeutic response markers including the PD-L1 and PD-1 expression pattern, genetic mutations within cancer cells and neoantigens, cancer epigenetics and effector T cell landscape, and microbiota. We further clarify the mechanisms of action of these markers and their roles in shaping, being shaped, and/or predicting therapeutic responses. We also discuss a variety of combinations with PD pathway blockade and their scientific rationales for cancer treatment. PMID:26936508

  12. Cellular and Molecular Mechanisms Underlie the Anti-Tumor Activities Exerted by Walterinnesia aegyptia Venom Combined with Silica Nanoparticles against Multiple Myeloma Cancer Cell Types

    PubMed Central

    Badr, Gamal; Al-Sadoon, Mohamed K.; Abdel-Maksoud, Mostafa A.; Rabah, Danny M.; El-Toni, Ahmed M.

    2012-01-01

    Multiple myeloma (MM) is a clonal disease of plasma cells that remains incurable despite the advent of several novel therapeutics. In this study, we aimed to delineate the impact of snake venom extracted from Walterinnesia aegyptia (WEV) alone or in combination with silica nanoparticles (WEV+NP) on primary MM cells isolated from patients diagnosed with MM as well as on two MM cell lines, U266 and RPMI 8226. The IC50 values of WEV and WEV+NP that significantly decreased MM cell viability without affecting the viability of normal peripheral mononuclear cells (PBMCs) were determined to be 25 ng/ml and 10 ng/ml, respectively. Although both WEV (25 ng/ml) and WEV+NP (10 ng/ml) decreased the CD54 surface expression without affecting the expression of CXCR4 (CXCL12 receptor) on MM cells, they significantly reduced the ability of CXC chemokine ligand 12 (CXCL12) to induce actin cytoskeleton rearrangement and the subsequent reduction in chemotaxis. It has been established that the binding of CXCL12 to its receptor CXCR4 activates multiple intracellular signal transduction pathways that regulate MM cell chemotaxis, adhesion, and proliferation. We found that WEV and WEV+NP clearly decreased the CXCL12/CXCR4-mediated activation of AKT, ERK, NFκB and Rho-A using western blot analysis; abrogated the CXCL12-mediated proliferation of MM cells using the CFSE assay; and induced apoptosis in MM cell as determined by PI/annexin V double staining followed by flow cytometry analysis. Monitoring the expression of B-cell CCL/Lymphoma 2 (Bcl-2) family members and their role in apoptosis induction after treatment with WEV or WEV+NP revealed that the combination of WEV with NP robustly decreased the expression of the anti-apoptotic effectors Bcl-2, BclXL and Mcl-1; conversely increased the expression of the pro-apoptotic effectors Bak, Bax and Bim; and altered the mitochondrial membrane potential in MM cells. Taken together, our data reveal the biological effects of WEV and WEV+NP and the

  13. Cellular and molecular mechanisms underlie the anti-tumor activities exerted by Walterinnesia aegyptia venom combined with silica nanoparticles against multiple myeloma cancer cell types.

    PubMed

    Badr, Gamal; Al-Sadoon, Mohamed K; Abdel-Maksoud, Mostafa A; Rabah, Danny M; El-Toni, Ahmed M

    2012-01-01

    Multiple myeloma (MM) is a clonal disease of plasma cells that remains incurable despite the advent of several novel therapeutics. In this study, we aimed to delineate the impact of snake venom extracted from Walterinnesia aegyptia (WEV) alone or in combination with silica nanoparticles (WEV+NP) on primary MM cells isolated from patients diagnosed with MM as well as on two MM cell lines, U266 and RPMI 8226. The IC(50) values of WEV and WEV+NP that significantly decreased MM cell viability without affecting the viability of normal peripheral mononuclear cells (PBMCs) were determined to be 25 ng/ml and 10 ng/ml, respectively. Although both WEV (25 ng/ml) and WEV+NP (10 ng/ml) decreased the CD54 surface expression without affecting the expression of CXCR4 (CXCL12 receptor) on MM cells, they significantly reduced the ability of CXC chemokine ligand 12 (CXCL12) to induce actin cytoskeleton rearrangement and the subsequent reduction in chemotaxis. It has been established that the binding of CXCL12 to its receptor CXCR4 activates multiple intracellular signal transduction pathways that regulate MM cell chemotaxis, adhesion, and proliferation. We found that WEV and WEV+NP clearly decreased the CXCL12/CXCR4-mediated activation of AKT, ERK, NFκB and Rho-A using western blot analysis; abrogated the CXCL12-mediated proliferation of MM cells using the CFSE assay; and induced apoptosis in MM cell as determined by PI/annexin V double staining followed by flow cytometry analysis. Monitoring the expression of B-cell CCL/Lymphoma 2 (Bcl-2) family members and their role in apoptosis induction after treatment with WEV or WEV+NP revealed that the combination of WEV with NP robustly decreased the expression of the anti-apoptotic effectors Bcl-2, Bcl(XL) and Mcl-1; conversely increased the expression of the pro-apoptotic effectors Bak, Bax and Bim; and altered the mitochondrial membrane potential in MM cells. Taken together, our data reveal the biological effects of WEV and WEV+NP and

  14. Antibiotic trapping by plasmid-encoded CMY-2 β-lactamase combined with reduced outer membrane permeability as a mechanism of carbapenem resistance in Escherichia coli.

    PubMed

    Goessens, Wil H F; van der Bij, Akke K; van Boxtel, Ria; Pitout, Johann D D; van Ulsen, Peter; Melles, Damian C; Tommassen, Jan

    2013-08-01

    A liver transplant patient was admitted with cholangitis, for which meropenem therapy was started. Initial cultures showed a carbapenem-susceptible (CS) Escherichia coli strain, but during admission, a carbapenem-resistant (CR) E. coli strain was isolated. Analysis of the outer membrane protein profiles showed that both CS and CR E. coli lacked the porins OmpF and OmpC. Furthermore, PCR and sequence analysis revealed that both CS and CR E. coli possessed bla(CTX-M-15) and bla(OXA-1). The CR E. coli strain additionally harbored bla(CMY-2) and demonstrated a >15-fold increase in β-lactamase activity against nitrocefin, but no hydrolysis of meropenem was detected. However, nitrocefin hydrolysis appeared strongly inhibited by meropenem. Furthermore, the CMY-2 enzyme demonstrated lower electrophoretic mobility after its incubation either in vitro or in vivo with meropenem, indicative of its covalent modification with meropenem. The presence of the acyl-enzyme complex was confirmed by mass spectrometry. By transformation of the CMY-2-encoding plasmid into various E. coli strains, it was established that both porin deficiency and high-level expression of the enzyme were needed to confer meropenem resistance. In conclusion, carbapenem resistance emerged by a combination of elevated β-lactamase production and lack of porin expression. Due to the reduced outer membrane permeability, only small amounts of meropenem can enter the periplasm, where they are trapped but not degraded by the large amount of the β-lactamase. This study, therefore, provides evidence that the mechanism of "trapping" by CMY-2 β-lactamase plays a role in carbapenem resistance.

  15. Mechanism of enhanced responses after combination photodynamic therapy (cPDT) in carcinoma cells involves C/EBP-mediated transcriptional upregulation of the coproporphyrinogen oxidase (CPO) gene

    NASA Astrophysics Data System (ADS)

    Anand, Sanjay; Hasan, Tayyaba; Maytin, Edward V.

    2013-03-01

    Photodynamic therapy (PDT) with aminolevulinate (ALA) is widely accepted as an effective treatment for superficial carcinomas and pre-cancers. However, PDT is still suboptimal for deeper tumors, mainly due to inadequate ALA penetration and subsequent conversion to PpIX. We are interested in improving the effectiveness of photodynamic therapy (PDT) for deep tumors, using a combination approach (cPDT) in which target protoporphyrin (PpIX) levels are significantly enhanced by differentiation caused by giving Vitamin D or methotrexate (MTX) for 3 days prior to ALAPDT. In LNCaP and MEL cells, a strong correlation between inducible differentiation and expression of C/EBP transcription factors, as well as between differentiation and mRNA levels of CPO (a key heme-synthetic enzyme), indicates the possibility of CPO transcriptional regulation by the C/EBPs. Sequence analysis of the first 1300 base pairs of the murine CPO upstream region revealed 15 consensus C/EBP binding sites. Electrophoretic Mobility Shift Assays (EMSA) proved that these sites form specific complexes that have strong, moderate or weak affinities for C/EBPs. However, in the context of the full-length CPO promoter, inactivation of any type of site (strong or weak) reduced CPO promoter activity (luciferase assay) to nearly the same extent, suggesting cooperative interactions. A comparative analysis of murine and human CPO promoters revealed possible protein-protein interactions between C/EBPs and several neighboring transcription factors such as NFkB, Sp1, AP-1, CBP/p300 and CREB (an enhanceosome complex). Overall, these results confirm that C/EBP's are important for CPO expression via complex mechanisms which upregulate PpIX and enhance the outcome of cPDT.

  16. [EFFICIENCY OF COMBINATION OF ROFLUMILAST AND QUERCETIN FOR CORRECTION OXYGEN- INDEPENDENT MECHANISMS AND PHAGOCYTIC ACTIVITY OF MACROPHAGE CELLS OF PATIENTS WITH ACUTE EXACERBATION OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE WHEN COMBINED WITH CORONARY HEART DISEASE].

    PubMed

    Gerych, P; Yatsyshyn, R

    2015-01-01

    Studied oxygen independent reaction and phagocytic activity of macrophage cells of patients with chronic obstructive pulmonary disease (COPD) II-III stage when combined with coronary heart disease (CHD). The increasing oxygen independent reactions monocytes and neutrophils and a decrease of the parameters that characterize the functional state of phagocytic cells, indicating a decrease in the functional capacity of macrophage phagocytic system (MPS) in patients with acute exacerbation of COPD, which runs as its own or in combination with stable coronary heart disease angina I-II. FC. Severity immunodeficiency state in terms of cellular component of nonspecific immunity in patients with acute exacerbation of COPD II-III stage in conjunction with the accompanying CHD increases with the progression of heart failure. Inclusion of basic therapy of COPD exacerbation and standard treatment of coronary artery disease and drug combinations Roflumilastand quercetin causes normalization of phagocytic indices MFS, indicating improved immune status and improves myocardial perfusion in terms of daily ECG monitoring.

  17. [The role of adenosine Al receptors and mitochondrial K+ATP channels in the mechanism of increasing the resistance to acute hypoxia in the combined effects of hypoxia and hypercapnia].

    PubMed

    Tregub, P P; Kulikov, V P; Stepanova, L A; Zabrodina, A S; Nagibaeva, M E

    2014-01-01

    We studied the role of the role of mitoK+ATp channels and Al-adenosine receptor in the mechanism of increasing the resistance to acute hypoxia after hypoxic, hypercapnic and hypercapnic-hypoxic preconditioning. It is shown that mitochondrial ATP-sensitive potassium channels and Al-adenosine receptors, an important mechanism of preconditioning have a high value to increase the resistance to acute hypoxia/ischemia in the combined effect of hypoxia and hypercapnia. However, with regard to the adenosine receptor, this mechanism is realized without the participation hypercapnic component, which apparently starts neuroprotection without activation of the adenosine Al receptors. PMID:25980226

  18. Mechanism of Chemoprevention against Colon Cancer Cells Using Combined Gelam Honey and Ginger Extract via mTOR and Wnt/β-catenin Pathways.

    PubMed

    Wee, Lee Heng; Morad, Noor Azian; Aan, Goon Jo; Makpol, Suzana; Wan Ngah, Wan Zurinah; Mohd Yusof, Yasmin Anum

    2015-01-01

    The PI3K-Akt-mTOR, Wnt/β-catenin and apoptosis signaling pathways have been shown to be involved in genesis of colorectal cancer (CRC). The aim of this study was to elucidate whether combination of Gelam honey and ginger might have chemopreventive properties in HT29 colon cancer cells by modulating the mTOR, Wnt/β-catenin and apoptosis signaling pathways. Treatment with Gelam honey and ginger reduced the viability of the HT29 cells dose dependently with IC50 values of 88 mg/ml and 2.15 mg/ml respectively, their while the combined treatment of 2 mg/ml of ginger with 31 mg/ml of Gelam honey inhibited growth of most HT29 cells. Gelam honey, ginger and combination induced apoptosis in a dose dependent manner with the combined treatment exhibiting the highest apoptosis rate. The combined treatment downregulated the gene expressions of Akt, mTOR, Raptor, Rictor, β-catenin, Gsk3β, Tcf4 and cyclin D1 while cytochrome C and caspase 3 genes were shown to be upregulated. In conclusion, the combination of Gelam honey and ginger may serve as a potential therapy in the treatment of colorectal cancer through inhibiton of mTOR, Wnt/β catenin signaling pathways and induction of apoptosis pathway.

  19. The effect of a combined biological and thermo-mechanical pretreatment of wheat straw on energy yields in coupled ethanol and methane generation.

    PubMed

    Theuretzbacher, Franz; Blomqvist, Johanna; Lizasoain, Javier; Klietz, Lena; Potthast, Antje; Horn, Svein Jarle; Nilsen, Paal J; Gronauer, Andreas; Passoth, Volkmar; Bauer, Alexander

    2015-10-01

    Ethanol and biogas are energy carriers that could contribute to a future energy system independent of fossil fuels. Straw is a favorable bioenergy substrate as it does not compete with food or feed production. As straw is very resistant to microbial degradation, it requires a pretreatment to insure efficient conversion to ethanol and/or methane. This study investigates the effect of combining biological pretreatment and steam explosion on ethanol and methane yields in order to improve the coupled generation process. Results show that the temperature of the steam explosion pretreatment has a particularly strong effect on possible ethanol yields, whereas combination with the biological pretreatment showed no difference in overall energy yield. The highest overall energy output was found to be 10.86 MJ kg VS(-1) using a combined biological and steam explosion pretreatment at a temperature of 200°C.

  20. Impact and mechanism of non-steroidal anti-inflammatory drugs combined with chemotherapeutic drugs on human lung cancer-nude mouse transplanted tumors

    PubMed Central

    SUN, WEIYI; CHEN, GANG

    2016-01-01

    The present study aimed to investigate the impact of indomethacin treatment combined with oxaliplatin treatment on the expression of cluster of differentiation 44 variant 6 (CD44v6), matrix metalloproteinase-2 (MMP-2) and survivin in human lung cancer-nude mouse transplanted tumors. The human lung adenocarcinoma (A549)-nude mouse transplanted tumor model was established, and the mice were divided into a control group, an indomethacin treatment group, an oxaliplatin treatment group and an indomethacin-oxaliplatin combination treatment group. The tumor inhibition rate was calculated following sacrificing of the mice. Immunohistochemical staining and fluorescence reverse transcription-quantitative polymerase chain reaction were utilized to detect the protein and messenger (m)RNA expression of CD44v6, MMP-2 and survivin. The tumor inhibition rates of the indomethacin group, the oxaliplatin group and the combination group were 26.67, 47.70 and 68.88%, respectively. The protein and mRNA expression levels of CD44v6, MMP-2 and survivin in the transplanted tumors of each treatment group were reduced compared with the control group (P<0.05), and those of the combination group were lower compared with the single-drug treatment groups (P<0.05). Survivin and MMP-2, MMP-2 and CD44v6, and MMP-2 and CD44v6 all exhibited linear positive correlation. The present study provides evidence that the administration of indomethacin alone, or in combination with oxaliplatin, may significantly inhibit the growth of lung cancer-nude mouse transplanted tumors and the expression of CD44v6, MMP-2 and survivin inside the tumor. The combination of non-steroidal anti-inflammatory drugs with chemotherapeutic drugs may improve the antitumor effects. PMID:27313765

  1. Investigation of mechanism of bone regeneration in a porous biodegradable calcium phosphate (CaP) scaffold by a combination of a multi-scale agent-based model and experimental optimization/validation.

    PubMed

    Zhang, Le; Qiao, Minna; Gao, Hongjie; Hu, Bin; Tan, Hua; Zhou, Xiaobo; Li, Chang Ming

    2016-08-21

    Herein, we have developed a novel approach to investigate the mechanism of bone regeneration in a porous biodegradable calcium phosphate (CaP) scaffold by a combination of a multi-scale agent-based model, experimental optimization of key parameters and experimental data validation of the predictive power of the model. The advantages of this study are that the impact of mechanical stimulation on bone regeneration in a porous biodegradable CaP scaffold is considered, experimental design is used to investigate the optimal combination of growth factors loaded on the porous biodegradable CaP scaffold to promote bone regeneration and the training, testing and analysis of the model are carried out by using experimental data, a data-mining algorithm and related sensitivity analysis. The results reveal that mechanical stimulation has a great impact on bone regeneration in a porous biodegradable CaP scaffold and the optimal combination of growth factors that are encapsulated in nanospheres and loaded into porous biodegradable CaP scaffolds layer-by-layer can effectively promote bone regeneration. Furthermore, the model is robust and able to predict the development of bone regeneration under specified conditions.

  2. Investigation of mechanism of bone regeneration in a porous biodegradable calcium phosphate (CaP) scaffold by a combination of a multi-scale agent-based model and experimental optimization/validation

    NASA Astrophysics Data System (ADS)

    Zhang, Le; Qiao, Minna; Gao, Hongjie; Hu, Bin; Tan, Hua; Zhou, Xiaobo; Li, Chang Ming

    2016-08-01

    Herein, we have developed a novel approach to investigate the mechanism of bone regeneration in a porous biodegradable calcium phosphate (CaP) scaffold by a combination of a multi-scale agent-based model, experimental optimization of key parameters and experimental data validation of the predictive power of the model. The advantages of this study are that the impact of mechanical stimulation on bone regeneration in a porous biodegradable CaP scaffold is considered, experimental design is used to investigate the optimal combination of growth factors loaded on the porous biodegradable CaP scaffold to promote bone regeneration and the training, testing and analysis of the model are carried out by using experimental data, a data-mining algorithm and related sensitivity analysis. The results reveal that mechanical stimulation has a great impact on bone regeneration in a porous biodegradable CaP scaffold and the optimal combination of growth factors that are encapsulated in nanospheres and loaded into porous biodegradable CaP scaffolds layer-by-layer can effectively promote bone regeneration. Furthermore, the model is robust and able to predict the development of bone regeneration under specified conditions.

  3. Length of mechanical restraint following haloperidol injections versus oral atypical antipsychotics for the initial treatment of acute schizophrenia: a propensity-matched analysis from the Japanese diagnosis procedure combination database.

    PubMed

    Nakamura, Mitsuhiro; Yasunaga, Hideo; Haraguchi, Tadashi; Ando, Shuntaro; Sugihara, Toru; Horiguchi, Hiromasa; Ohe, Kazuhiko; Matsuda, Shinya; Fushimi, Kiyohide

    2013-10-30

    Differences in effectiveness between haloperidol injection and oral atypical antipsychotics in the acute-phase treatment of schizophrenia are not well examined. We retrospectively investigated whether these treatment options affected the length of mechanical restraint. We used the Japanese Diagnosis Procedure Combination Database to identify schizophrenia patients who were involuntarily hospitalized and receiving mechanical restraint between July and December, 2006-2009. Data included patient demographics, use of antipsychotics, and number of days on which patients underwent mechanical restraint. Propensity score matching was performed to compare the number of days of mechanical restraint between the haloperidol injection group and the oral atypical antipsychotics group. We used survival analysis to examine whether the initial difference in treatment affected the number of days of mechanical restraint. Cox regression was performed to compare the concurrent effects of various factors. Among 1731 eligible patients, 574 were treated with haloperidol injections and 420 with atypical antipsychotics. Matching produced 274 patients in each group. Cox regression analysis showed that the initial therapeutic agents did not significantly affect the number of days of mechanical restraint. The results indicate that atypical antipsychotics were as effective as haloperidol injections in the acute-phase treatment of schizophrenia.

  4. Theoretical analysis of geometry and NMR isotope shift in hydrogen-bonding center of photoactive yellow protein by combination of multicomponent quantum mechanics and ONIOM scheme.

    PubMed

    Kanematsu, Yusuke; Tachikawa, Masanori

    2014-11-14

    Multicomponent quantum mechanical (MC_QM) calculation has been extended with ONIOM (our own N-layered integrated molecular orbital + molecular mechanics) scheme [ONIOM(MC_QM:MM)] to take account of both the nuclear quantum effect and the surrounding environment effect. The authors have demonstrated the first implementation and application of ONIOM(MC_QM:MM) method for the analysis of the geometry and the isotope shift in hydrogen-bonding center of photoactive yellow protein. ONIOM(MC_QM:MM) calculation for a model with deprotonated Arg52 reproduced the elongation of O-H bond of Glu46 observed by neutron diffraction crystallography. Among the unique isotope shifts in different conditions, the model with protonated Arg52 with solvent effect reasonably provided the best agreement with the corresponding experimental values from liquid NMR measurement. Our results implied the availability of ONIOM(MC_QM:MM) to distinguish the local environment around hydrogen bonds in a biomolecule.

  5. Theoretical analysis of geometry and NMR isotope shift in hydrogen-bonding center of photoactive yellow protein by combination of multicomponent quantum mechanics and ONIOM scheme

    SciTech Connect

    Kanematsu, Yusuke; Tachikawa, Masanori

    2014-11-14

    Multicomponent quantum mechanical (MC-QM) calculation has been extended with ONIOM (our own N-layered integrated molecular orbital + molecular mechanics) scheme [ONIOM(MC-QM:MM)] to take account of both the nuclear quantum effect and the surrounding environment effect. The authors have demonstrated the first implementation and application of ONIOM(MC-QM:MM) method for the analysis of the geometry and the isotope shift in hydrogen-bonding center of photoactive yellow protein. ONIOM(MC-QM:MM) calculation for a model with deprotonated Arg52 reproduced the elongation of O–H bond of Glu46 observed by neutron diffraction crystallography. Among the unique isotope shifts in different conditions, the model with protonated Arg52 with solvent effect reasonably provided the best agreement with the corresponding experimental values from liquid NMR measurement. Our results implied the availability of ONIOM(MC-QM:MM) to distinguish the local environment around hydrogen bonds in a biomolecule.

  6. Combined meso-scale modeling and experimental investigation of the effect of mechanical damage on the transport properties of cementitious composites

    NASA Astrophysics Data System (ADS)

    Raghavan, Balaji; Niknezhad, Davood; Bernard, Fabrice; Kamali-Bernard, Siham

    2016-09-01

    The transport properties of cementitious composites such as concrete are important indicators of their durability, and are known to be heavily influenced by mechanical loading. In the current work, we use meso-scale hygro-mechanical modeling with a morphological 3D two phase mortar-aggregate model, in conjunction with experimentally obtained properties, to investigate the coupling between mechanical loading and damage and the permeability of the composite. The increase in permeability of a cylindrical test specimen at 28% aggregate fraction during a uniaxial displacement-controlled compression test at 85% of the peak load was measured using a gas permeameter. The mortar's mechanical behavior is assumed to follow the well-known compression damaged plasticity (CDP) model with isotropic damage, at varying thresholds, and obtained from different envelope curves. The damaged intrinsic permeability of the mortar evolves according to a logarithmic matching law with progressive loading. We fit the matching law parameters to the experimental result for the test specimen by inverse identification using our meso-scale model. We then subject a series of virtual composite specimens to quasi-static uniaxial compressive loading with varying boundary conditions to obtain the simulated damage and strain evolutions, and use the damage data and the previously identified parameters to determine the evolution of the macroscopic permeability tensor for the specimens, using a network model. We conduct a full parameter study by varying aggregate volume fraction, granulometric distribution, loading/boundary conditions and "matching law" parameters, as well as for different strain-damage thresholds and uniaxial loading envelope curves. Based on this study, we propose Avrami equation-based upper and lower bounds for the evolution of the damaged permeability of the composite.

  7. Combining systems pharmacology, transcriptomics, proteomics, and metabolomics to dissect the therapeutic mechanism of Chinese herbal Bufei Jianpi formula for application to COPD

    PubMed Central

    Zhao, Peng; Yang, Liping; Li, Jiansheng; Li, Ya; Tian, Yange; Li, Suyun

    2016-01-01

    Bufei Jianpi formula (BJF) has long been used as a therapeutic agent in the treatment of COPD. Systems pharmacology identified 145 active compounds and 175 potential targets of BJF in a previous study. Additionally, BJF was previously shown to effectively prevent COPD and its comorbidities, such as ventricular hypertrophy, by inhibition of inflammatory cytokine production, matrix metalloproteinases expression, and other cytokine production, in vivo. However, the system-level mechanism of BJF for the treatment of COPD is still unclear. The aim of this study was to gain insight into its system-level mechanisms by integrating transcriptomics, proteomics, and metabolomics together with systems pharmacology datasets. Using molecular function, pathway, and network analyses, the genes and proteins regulated in COPD rats and BJF-treated rats could be mainly attributed to oxidoreductase activity, antioxidant activity, focal adhesion, tight junction, or adherens junction. Furthermore, a comprehensive analysis of systems pharmacology, transcript, protein, and metabolite datasets is performed. The results showed that a number of genes, proteins, metabolites regulated in BJF-treated rats and potential target proteins of BJF were involved in lipid metabolism, cell junction, oxidative stress, and inflammatory response, which might be the system-level therapeutic mechanism of BJF treatment. PMID:27042044

  8. [Movement-adsorption and its mechanism of Cd in soil under combining effects of electrokinetics and a new type of bamboo charcoal].

    PubMed

    Ma, Jian-Wei; Wang, Hui; Luo, Qi-Shi

    2007-08-01

    The characteristics of migration and its influencing factor of cadmium in sandy loam soil by uniform electrokinetics as well as the adsorption property by a new material-bamboo charcoal were investigated through bench-scale experiments, and the feasibility of using electrokinetic technique combined with the newly developed bamboo charcoal for remediation of cadmium contaminated soils was analyzed as well. The results show that the bamboo charcoal is good adsorption material which has comparably strong adsorption effect on Cd, bearing potential in future use, which could be simulated by both Freundlich and Langmuir models (R2 > 0.96). The migration rates of cadmium in sandy loam were high up to 0. 6786 - 0.6875cm/h under an electric gradient of 1.0V/cm, depending upon the concentration of cadmium and the distribution of electric field density. Electrokinetics effectively transported the heavy metal in the soil. In the new electrokinetic tech combining the bamboo charcoal with the same electric gradient above under the polarity reversal period of 48 hours, the cadmium in the soil could be wiped off with high efficiency (removal efficiency 79.6% in 12 days) and the pH together with water content could be well retained. The electric current in the process changed periodically according to the reversal. As a new technique, the electrokinetic movement-bamboo charcoal adsorption holds high potential in future use.

  9. [Movement-adsorption and its mechanism of Cd in soil under combining effects of electrokinetics and a new type of bamboo charcoal].

    PubMed

    Ma, Jian-Wei; Wang, Hui; Luo, Qi-Shi

    2007-08-01

    The characteristics of migration and its influencing factor of cadmium in sandy loam soil by uniform electrokinetics as well as the adsorption property by a new material-bamboo charcoal were investigated through bench-scale experiments, and the feasibility of using electrokinetic technique combined with the newly developed bamboo charcoal for remediation of cadmium contaminated soils was analyzed as well. The results show that the bamboo charcoal is good adsorption material which has comparably strong adsorption effect on Cd, bearing potential in future use, which could be simulated by both Freundlich and Langmuir models (R2 > 0.96). The migration rates of cadmium in sandy loam were high up to 0. 6786 - 0.6875cm/h under an electric gradient of 1.0V/cm, depending upon the concentration of cadmium and the distribution of electric field density. Electrokinetics effectively transported the heavy metal in the soil. In the new electrokinetic tech combining the bamboo charcoal with the same electric gradient above under the polarity reversal period of 48 hours, the cadmium in the soil could be wiped off with high efficiency (removal efficiency 79.6% in 12 days) and the pH together with water content could be well retained. The electric current in the process changed periodically according to the reversal. As a new technique, the electrokinetic movement-bamboo charcoal adsorption holds high potential in future use. PMID:17926419

  10. Mechanisms of the antitumor activity of human Vγ9Vδ2 T cells in combination with zoledronic acid in a preclinical model of neuroblastoma.

    PubMed

    Di Carlo, Emma; Bocca, Paola; Emionite, Laura; Cilli, Michele; Cipollone, Giuseppe; Morandi, Fabio; Raffaghello, Lizzia; Pistoia, Vito; Prigione, Ignazia

    2013-05-01

    Low expression of surface major histocompatibility complex (MHC) class I molecules and defects in antigen processing machinery make human neuroblastoma (NB) cells appropriate targets for MHC unrestricted immunotherapeutic approaches. Human T-cell receptor (TCR) Vγ9Vδ2 lymphocytes exert MHC-unrestricted antitumor activity and are activated by phosphoantigens, whose expression in cancer cells is increased by aminobisphosphonates. With this background, we have investigated the in vivo anti-NB activity of human Vγ9Vδ2 lymphocytes and zoledronic acid (ZOL). SH-SY-5Y human NB cells were injected in the adrenal gland of immunodeficient mice. After 3 days, mice received ZOL or human Vγ9Vδ2 T cells or both agents by intravenous administration once a week for 4 weeks. A significantly improved overall survival was observed in mice receiving Vγ9Vδ2 T cells in combination with ZOL. Inhibition of tumor cell proliferation, angiogenesis and lymphangiogenesis, and increased tumor cell apoptosis were detected. Vγ9Vδ2 T lymphocytes were attracted to NB-tumor masses of mice receiving ZOL where they actively modified tumor microenvironment by producing interferon-γ (IFN-γ), that in turn induced CXCL10 expression in NB cells. This study shows that human Vγ9Vδ2 T cells and ZOL in combination inhibit NB growth in vivo and may provide the rationale for a phase I clinical trial in patients with high-risk NB.

  11. Mechanism of rat osteosarcoma cell apoptosis induced by a combination of low-intensity ultrasound and 5-aminolevulinic acid in vitro.

    PubMed

    Li, Y N; Zhou, Q; Yang, B; Hu, Z; Wang, J H; Li, Q S; Cao, W W

    2015-01-01

    We investigated the killing effect of low-intensity ultrasound combined with 5-aminolevulinic acid (5-ALA) on the rat osteosarcoma cell line UMR-106. Logarithmic-phase UMR-106 cells were divided into a control group, ultrasound group and 5-ALA group. The cell apoptotic rate, production of reactive oxygen species, and the change in mitochondrial membrane potential were analyzed by flow cytometry; ultrastructural changes were observed by transmission electron microscopy. Using low-intensity ultrasound at 1.0 MHz and 2.0 W/cm(2) plus 5-ALA at a concentration of 2 mM, the apoptotic rate of the sonodynamic therapy group was 27.2 ± 3.4% which was significantly higher than that of the control group, ultrasound group, and 5-ALA group (P < 0.05). The production of reactive oxygen species was 32.6 ± 2.2% and the decrease in mitochondrial membrane potential was 39.5 ± 2.5%. The 33342 staining showed nuclear condensation and fragmentation in the ultrasound group and 5-ALA group. Structural changes in the cell membrane, mitochondria, Golgi apparatus, and other organelles observed by transmission electron microscopy included formation of apoptotic bodies. The killing effect of low-intensity ultrasound combined with 5-ALA on UMR-106 cells was significant. Cell apoptosis played a vital role in the killing effect, and the mitochondria pathway contributed to the apoptosis of UMR-106 cells. PMID:26345893

  12. Application and possible mechanisms of combining LLLT (low level laser therapy), infrared hyperthermia and ionizing radiation in the treatment of cancer

    NASA Astrophysics Data System (ADS)

    Abraham, Edward H.; Woo, Van H.; Harlin-Jones, Cheryl; Heselich, Anja; Frohns, Florian

    2014-02-01

    Benefit of concomitant infrared hyperthermia and low level laser therapy and ionizing radiation is evaluated in this study. The purpose/objectives: presentation with locally advanced bulky superficial tumors is clinically challenging. To enhance the efficacy of chemotherapy and IMRT (intensity-modulated radiation therapy) and/or electron beam therapy we have developed an inexpensive and clinically effective infrared hyperthermia approach that combines black-body infrared radiation with halogen spectrum radiation and discrete wave length infrared clinical lasers LLLT. The goal is to produce a composite spectrum extending from the far infrared to near infrared and portions of the visible spectrum with discrete penetrating wavelengths generated by the clinical infrared lasers with frequencies of 810 nm and/or 830 nm. The composite spectrum from these sources is applied before and after radiation therapy. We monitor the surface and in some cases deeper temperatures with thermal probes, but use an array of surface probes as the limiting safe thermal constraint in patient treatment while at the same time maximizing infrared entry to deeper tissue layers. Fever-grade infrared hyperthermia is produced in the first centimeters while non-thermal infrared effects act at deeper tissue layers. The combination of these effects with ionizing radiation leads to improved tumor control in many cancers.

  13. Investigation of the Degradation Mechanisms of a Variety of Organic Photovoltaic Devices by Combination of Imaging Techniques—the ISOS-3Inter-laboratory Collaboration

    SciTech Connect

    Germack D.; Rosch, R.; Tanenbaum, D.M.; Jorgensen, M.; Seeland, M.; Barenklau, M.; Hermenau, M.; Voroshazi, E.; Lloyd, M.T.; Galagan, Y.; Zimmermann, B.; Wurfel, U.; Hosel, M.; Dam, H.F.; Gevorgyan, S.A.; Kudret, S.; Maes, W.; Lutsen, L.; Vanderzande, D.; Andriessen, R.; Teran-Escobar, G.; Lira-Cantu, M.; Rivaton, A.; Uzunoglu, G.Y.; Andreasen, B.; Madsen, M.V.; Norrman, K.; Hoppe, H.; Krebs, F.C.

    2012-04-01

    The investigation of degradation of seven distinct sets (with a number of individual cells of n {ge} 12) of state of the art organic photovoltaic devices prepared by leading research laboratories with a combination of imaging methods is reported. All devices have been shipped to and degraded at Risoe DTU up to 1830 hours in accordance with established ISOS-3 protocols under defined illumination conditions. Imaging of device function at different stages of degradation was performed by laser-beam induced current (LBIC) scanning; luminescence imaging, specifically photoluminescence (PLI) and electroluminescence (ELI); as well as by lock-in thermography (LIT). Each of the imaging techniques exhibits its specific advantages with respect to sensing certain degradation features, which will be compared and discussed here in detail. As a consequence, a combination of several imaging techniques yields very conclusive information about the degradation processes controlling device function. The large variety of device architectures in turn enables valuable progress in the proper interpretation of imaging results - hence revealing the benefits of this large scale cooperation in making a step forward in the understanding of organic solar cell aging and its interpretation by state-of-the-art imaging methods.

  14. Possible Mechanism of Therapeutic Effect of 3-Methyl-1-phenyl-2-pyrazolin-5-one and Bone Marrow Stromal Cells Combination Treatment in Rat Ischemic Stroke Model

    PubMed Central

    Shen, Li-Hua; Chen, Jin; Shen, Hua-Chao; Ye, Min; Liu, Xiao-Fei; Ding, Wen-Sen; Sheng, Ya-Feng; Ding, Xin-Sheng

    2016-01-01

    Background: The functional improvement following bone marrow stromal cells (BMSCs) transplantation after stroke is directly related to the number of engrafted cells and neurogenesis in the injured brain. Here, we tried to evaluate whether 3-methyl-1-phenyl-2-pyrazolin-5-one (MCI-186), a free radical scavenger, might influence BMSCs migration to ischemic brain, which could promote neurogenesis and thereby enhance treatment effects after stroke. Methods: Rat transient middle cerebral artery occlusion (MCAO) model was established. Two separate MCAO groups were administered with either MCI-186 or phosphate-buffered saline (PBS) solution to evaluate the expression of stromal cell-derived factor-1 (SDF-1) in ischemic brain, and compared to that in sham group (n = 5/group/time point[at 1, 3, and 7 days after operation]). The content of chemokine receptor-4 (CXCR4, a main receptor of SDF-1) at 7 days after operation was also observed on cultured BMSCs. Another four MCAO groups were intravenously administered with either PBS, MCI-186, BMSCs (2 × 106), or a combination of MCI-186 and BMSCs (n = 10/group). 5-bromo-2-deoxyuridine (BrdU) and Nestin double-immunofluorescence staining was performed to identify the engrafted BMSCs and neuronal differentiation. Adhesive-removal test and foot-fault evaluation were used to test the neurological outcome. Results: MCI-186 upregulated the expression of SDF-1 in ischemic brain and CXCR4 content in BMSCs was enhanced after hypoxic stimulation. When MCAO rats were treated with either MCI-186, BMSCs, or a combination of MCI-186 and BMSCs, the neurologic function was obviously recovered as compared to PBS control group (P < 0.01 or 0.05, respectively). Combination therapy represented a further restoration, increased the number of BMSCs and Nestin+ cells in ischemic brain as compared with BMSCs monotherapy (P < 0.01). The number of engrafted-BMSCs was correlated with the density of neuronal cells in ischemic brain (r = 0.72, P < 0.01) and

  15. Determining changes in the state of stress associated with an earthquake via combined focal mechanism and moment tensor analysis: Application to the 2013 Awaji Island earthquake, Japan

    NASA Astrophysics Data System (ADS)

    Matsumoto, Satoshi; Katao, Hiroshi; Iio, Yoshihisa

    2015-05-01

    One approach that can be used to evaluate the potential for an earthquake occurrence is the detection of the stress concentration at an earthquake fault. While the stress fields for pre- and post-seismic event stages differ, this change cannot provide information regarding the potential for an earthquake. Here, we propose a detection method for states of stress that uses focal mechanism data from microearthquakes. The state of stress can be defined both by the background stress and by a moment tensor equivalent to the stress concentration. We applied this method to actual focal mechanism data from the 2013 Awaji Island earthquake (M6.3), Japan, and the results showed the presence of stress concentration around the earthquake fault before the mainshock. In addition, the regional differential stress was shown to be about 13 MPa. The magnitude of the obtained stress concentration in the focal area and the high dip angle of the mainshock fault imply that the faulting occurred in the crust where it was overpressurized to a level near the lithostatic pressure.

  16. Ordering mechanism of stacked CdSe/ZnS{sub x}Se{sub 1-x} quantum dots: A combined reciprocal-space and real-space approach

    SciTech Connect

    Schmidt, Th.; Roventa, E.; Clausen, T.; Flege, J. I.; Alexe, G.; Rosenauer, A.; Hommel, D.; Falta, J.; Bernstorff, S.; Kuebel, C.

    2005-11-15

    The vertical and lateral ordering of stacked CdSe quantum dot layers embedded in ZnS{sub x}Se{sub 1-x} has been investigated by means of grazing incidence small angle x-ray scattering and transmission electron microscopy. Different growth parameters have been varied in order to elucidate the mechanisms leading to quantum dot correlation. From the results obtained for different numbers of quantum dot layers, we conclude on a self-organized process which leads to increasing ordering for progressive stacking. The dependence on the spacer layer thickness indicates that strain induced by lattice mismatch drives the ordering process, which starts to break down for too thick spacer layers in a thickness range from 45 to 80 A. Typical quantum dot distances in a range from about 110 to 160 A have been found. A pronounced anisotropy of the quantum dot correlation has been observed, with the strongest ordering along the [110] direction. Since an increased ordering is found with increasing growth temperature, the formation of stacking faults as an additional mechanism for quantum dot alignment can be ruled out.

  17. Vitamin K3 and vitamin C alone or in combination induced apoptosis in leukemia cells by a similar oxidative stress signalling mechanism

    PubMed Central

    2011-01-01

    Background Secondary therapy-related acute lymphoblastic leukemia might emerge following chemotherapy and/or radiotherapy for primary malignancies. Therefore, other alternatives should be pursued to treat leukemia. Results It is shown that vitamin K3- or vitamin C- induced apoptosis in leukemia cells by oxidative stress mechanism involving superoxide anion radical and hydrogen peroxide generation, activation of NF-κB, p53, c-Jun, protease caspase-3 activation and mitochondria depolarization leading to nuclei fragmentation. Cell death was more prominent when Jurkat and K562 cells are exposed to VC and VK3 in a ratio 1000:1 (10 mM: 10 μM) or 100:1 (300 μM: 3 μM), respectively. Conclusion We provide for the first time in vitro evidence supporting a causative role for oxidative stress in VK3- and VC-induced apoptosis in Jurkat and K562 cells in a domino-like mechanism. Altogether these data suggest that VK3 and VC should be useful in the treatment of leukemia. PMID:21663679

  18. Investigation of the Abstraction and Dissociation Mechanism in the Nitrogen Trifluoride Channels: Combined Post-Hartree-Fock and Transition State Theory Approaches.

    PubMed

    Claudino, D; Gargano, R; Carvalho-Silva, Valter H; E Silva, Geraldo M; da Cunha, W F

    2016-07-21

    The present paper concludes our series of kinetics studies on the reactions involved in the complex mechanism of nitrogen trifluoride decomposition. Two other related reactions that, along with this mechanism, take part in an efficient boron nitride growth process are also investigated. We report results concerning two abstraction reactions, namely NF2 + N ⇄ 2NF and NF3 + NF ⇄ 2NF2, and two dissociations, N2F4 ⇄ 2NF2 and N2F3 ⇄ NF2 + NF. State-of-the-art electronic structure calculations at the CCSD(T)/cc-pVTZ level of theory were considered to determine geometries and frequencies of reactants, products, and transition states. Extrapolation of the energies to the complete basis set limit was used to obtain energies of all the species. We applied transition state theory to compute thermal rate constants including Wigner, Eckart, Bell, and deformed theory corrections in order to take tunneling effects into account. The obtained results are in good agreement with the experimental data available in the literature and are expected to provide a better phenomenological understanding of the NF3 decomposition role in the boron nitride growth for a wide range of temperature values. PMID:27355487

  19. A combined experimental and computational study of the catalytic dehydration of glycerol on microporous zeolites: an investigation of the reaction mechanism and acrolein selectivity.

    PubMed

    Lin, Xufeng; Lv, Yanhong; Qu, Yuanyuan; Zhang, Guodong; Xi, Yanyan; Phillips, David L; Liu, Chenguang

    2013-12-14

    The catalytic activity and the acrolein selectivity for liquid phase glycerol dehydration on β zeolites (HNa-β-k) were found to be dependent on the reaction temperature as well as on the amount of acid sites on the zeolites. An increase in the reaction temperature favors the acrolein selectivity. The acrolein selectivity increases with the Na(+)/H(+) ratio and the glycerol conversion decreases with it so that a maximum acrolein yield is obtained when a certain amount of acidic sites are replaced by non-active Na(+) sites. The computational results indicate that 3-hydoxylpropanal (HPA) is an important intermediate that determines the final product selectivity. The relative rates of the different reaction pathways for HAP can be affected by the amount of water molecules involved in its homogeneous reaction. Based on the reaction mechanism proposed, it was hypothesized that smaller pores reduce activity but increase selectivity to acrolein, and results of the H-MFI zeolite were consistent with this hypothesis. Our work provides important insight into the overall landscape of the reaction mechanism and can be used to help design reaction systems that have good acrolein selectivity for the liquid phase glycerol dehydration reactions.

  20. Investigation of the Abstraction and Dissociation Mechanism in the Nitrogen Trifluoride Channels: Combined Post-Hartree-Fock and Transition State Theory Approaches.

    PubMed

    Claudino, D; Gargano, R; Carvalho-Silva, Valter H; E Silva, Geraldo M; da Cunha, W F

    2016-07-21

    The present paper concludes our series of kinetics studies on the reactions involved in the complex mechanism of nitrogen trifluoride decomposition. Two other related reactions that, along with this mechanism, take part in an efficient boron nitride growth process are also investigated. We report results concerning two abstraction reactions, namely NF2 + N ⇄ 2NF and NF3 + NF ⇄ 2NF2, and two dissociations, N2F4 ⇄ 2NF2 and N2F3 ⇄ NF2 + NF. State-of-the-art electronic structure calculations at the CCSD(T)/cc-pVTZ level of theory were considered to determine geometries and frequencies of reactants, products, and transition states. Extrapolation of the energies to the complete basis set limit was used to obtain energies of all the species. We applied transition state theory to compute thermal rate constants including Wigner, Eckart, Bell, and deformed theory corrections in order to take tunneling effects into account. The obtained results are in good agreement with the experimental data available in the literature and are expected to provide a better phenomenological understanding of the NF3 decomposition role in the boron nitride growth for a wide range of temperature values.

  1. NUCLEAR CROSS-SECTION CALCULATIONS IN THE 1 MEV TO 5 GEV RANGE WITH COMBINED SEMI-CLASSICAL AND QUANTUM MECHANICAL MODELS

    SciTech Connect

    Guimaraes, F.B.

    2002-03-07

    In this work we describe neutron and proton induced reaction cross-sections for iron produced by the codes TNG and CEM95 in the 5 to 300 MeV energy range. TNG calculations cover the 5-90 MeV range, while CEM95 covers the 50-300 MeV high energy range. The two codes show some disagreements in the overlap energy range, both among themselves and with the experimental data, which are presently being addressed. The experimental data used are from NNDC and/or from LA150 NSE references. We also describe some developments for combining TNG and CEM95 into a new code called CETNG (Cascade Exciton TNG).

  2. A hybrid approach to determining cornea mechanical properties in vivo using a combination of nano-indentation and inverse finite element analysis.

    PubMed

    Abyaneh, M H; Wildman, R D; Ashcroft, I A; Ruiz, P D

    2013-11-01

    An analysis of the material properties of porcine corneas has been performed. A simple stress relaxation test was performed to determine the viscoelastic properties and a rheological model was built based on the Generalized Maxwell (GM) approach. A validation experiment using nano-indentation showed that an isotropic GM model was insufficient for describing the corneal material behaviour when exposed to a complex stress state. A new technique was proposed for determining the properties, using a combination of nano-indentation experiment, an isotropic and orthotropic GM model and inverse finite element method. The good agreement using this method suggests that this is a promising technique for measuring material properties in vivo and further work should focus on the reliability of the approach in practice. PMID:23816808

  3. Solvent-dependent "turn-on" fluorescence chemosensor for Mg2+ based on combination of Cdbnd N isomerization and inhibition of ESIPT mechanisms

    NASA Astrophysics Data System (ADS)

    Liu, Zhaodi; Xu, Huajie; Chen, Shuisheng; Sheng, Liangquan; Zhang, Hong; Hao, Fuying; Su, Pengfei; Wang, Wenlong

    2015-10-01

    A fluorescent chemosensor (L) for Mg2+ has been synthesized and characterized, which exhibits turn-on fluorescence response for Mg2+ only in alcohol solvent (methanol or ethanol) with high sensitivity and selectivity. But in both nonpolar and polar solvents (cyclohexane, DCM, DMSO or MeCN), L showed negligible fluorescent response for Mg2+. In order to discover the unique phenomenon, optical measurements, liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) and a high performance liquid chromatography with a fluorescence detector (HPLC-FLD) of L and L with Mg2+ ions in solvents were studied. In alcohol solvent, [L + alcohol molecule] was formed and the mechanism aspect of L concerning the remarkable fluorescence response for Mg2+ has been discussed.

  4. Ligand-exchange mechanism: new insight into solid-phase extraction of uranium based on a combined experimental and theoretical study.

    PubMed

    Tian, Yin; Fu, Jia; Zhang, Yi; Cao, Kecheng; Bai, Chiyao; Wang, Dongqi; Li, Shoujian; Xue, Ying; Ma, Lijian; Zheng, Chong

    2015-03-21

    In numerous reports on selective solid-phase extraction (SPE) of uranium, the extraction of uranium is generally accepted as a direct coordination of the ligands on the solid matrix with the uranyl, in which the critical effect of the hydration shell on the uranyl is neglected. The related mechanism in the extraction process remains unclear. Herein, the detailed calculation of activation energy and the geometry of the identified transition states reveal that the uranium extraction by a newly-synthesized urea-functionalized graphite oxide (Urea-GO) is in essence an exchange process between the ligands on Urea-GO and the coordinated water molecules in the first hydration shell of the uranyl. Moreover, we demonstrate that it is the ketone oxygen in the urea ligand to displace the coordinated water molecule of uranyl due to its stronger bonding ability and lower steric-hindrance, whereas the nitrogen atom in the same ligand is proved to be an electron donor that enables the oxygen atom to have stronger affinity for uranium through electron delocalization effects evaluated on the basis of calculations of the second-order interaction energy between donor and acceptor orbitals. We therefore propose a new ligand-exchange mechanism for the SPE process. This study advances the fundamental understanding of uranium extraction, and provides theoretical and practical guidance on ligand design for selective complexation of uranium(VI) and other metal ions in aqueous solution. Finally, the effect of nitrate ions on the extraction of uranyl was successfully explained based on the experimental and theoretical study.

  5. Solvation Mechanism of Task-Specific Ionic Liquids in Water: A Combined Investigation Using Classical Molecular Dynamics and Density Functional Theory.

    PubMed

    Yuvaraj, Surya V J; Zhdanov, Ravil K; Belosludov, Rodion V; Belosludov, Vladimir R; Subbotin, Oleg S; Kanie, Kiyoshi; Funaki, Kenji; Muramatsu, Atsushi; Nakamura, Takashi; Kawazoe, Yoshiyuki

    2015-10-01

    The solvation behavior of task-specific ionic liquids (TSILs) containing a common, L-histidine derived imidazolium cation [C20H28N3O3](+) and different anions, bromide-[Br](-) and bis(trifluoromethylsulfonyl)amide-[NTF2](-), in water is examined, computationally. These amino acid functionalized ionic liquids (ILs) are taken into account because of their ability to react with rare earth metal salts. It has been noted that the TSIL with [Br](-) is more soluble than its counterpart TSIL with [NTF2](-), experimentally. In this theoretical work, the combined classical molecular dynamics (CMD) and density functional theory (DFT) calculations are performed to study the behavior of the bulk phase of these two TSILs in the vicinity of water (H2O) molecules with different concentrations. Initially, all the constructed systems are equilibrated using the CMD method. The final structures of the equilibrated systems are extracted for DFT calculations. Under CMD operation, the radial distribution function (RDF) plots and viscosity of TSILs are analyzed to understand the effect of water on TSILs. In the DFT regime, binding energy per H2O, charge transfer, charge density mapping, and electronic density of states (EDOS) analyses are done. The CMD results along with the DFT results are consolidated to support the hydrophilic and hydrophobic nature of the TSILs. Interestingly, we have found a strong correlation between the viscosity and the EDOS results that leads to an understanding of the hydration properties of the TSILs.

  6. Performance enhancement of polymer electrolyte fuel cells by combining liquid removal mechanisms of a gas diffusion layer with wettability distribution and a gas channel with microgrooves

    NASA Astrophysics Data System (ADS)

    Utaka, Yoshio; Koresawa, Ryo

    2016-08-01

    Although polymer electrolyte fuel cells (PEFCs) are commercially available, there are still many problems that need to be addressed to improve their performance and increase their usage. At a high current density, generated water accumulates in the gas diffusion layer and in the gas channels of the cathode. This excess water obstructs oxygen transport, and as a result, cell performance is greatly reduced. To improve the cell performance, the effective removal of the generated water and the promotion of oxygen diffusion in the gas diffusion layer (GDL) are necessary. In this study, two functions proposed in previous reports were combined and applied to a PEFC: a hybrid GDL to form an oxygen diffusion path using a wettability distribution and a gas separator with microgrooves to enhance liquid removal. For a PEFC with a hybrid GDL and a gas separator with microgrooves, the concentration overvoltage of the PEFC was reduced, and the current density limit and maximum power density were increased compared with a conventional PEFC. Moreover, the stability of the cell voltage was markedly improved.

  7. Combined capillary electrophoresis and high performance liquid chromatography studies on the kinetics and mechanism of the hydrogen peroxide-thiocyanate reaction in a weakly alkaline solution.

    PubMed

    Hu, Ying; Song, Yanan; Horváth, Attila K; Cui, Yin; Ji, Chen; Zhao, Yuemin; Gao, Qingyu

    2014-03-01

    The hydrogen peroxide-thiocyanate reaction has been reinvestigated by means of capillary electrophoresis and high performance liquid chromatography under weakly alkaline conditions at 25.0±0.1 °C. Concentration-time series of thiocyanate, sulfate and cyanate have been followed by capillary electrophoresis as well as that of thiocyanate and hydrogen peroxide by HPLC. It has been clearly demonstrated that OxSCN(-) (where x=1, 2 and 3) cannot be accumulated in detectable amount in contrast to the results of Christy and Egeberg, hence these species can only be regarded as short-lived intermediates. It has been shown that the overall rate law is first-order with respect to both reactants, but no pH-dependence was observed within the pH range of 8.86-10.08. A simple kinetic model has been proposed to fit all the concentration-time curves simultaneously at five different pHs demonstrating the powerful combination of the experimental techniques CE and HPLC with simultaneous evaluation of kinetic curves. It is also enlightened that the quality of the buffer strongly affects the rate of the overall reaction that increases in the order of application of ammonia, phosphate, carbonate and borate, respectively at a constant ionic strength and pH.

  8. Recanalization of Acute and Subacute Venous and Synthetic Bypass-Graft Occlusions With a Mechanical Rotational Catheter

    SciTech Connect

    Wissgott, Christian Kamusella, Peter; Andresen, Reimer

    2013-08-01

    PurposePercutaneous mechanical thrombectomy (PMT) is now established as an alternative treatment of acute arterial occlusions in addition to fibrinolysis and surgical thrombectomy. The objective of this retrospective study was the investigation of a rotational atherothrombectomy catheter in terms of safety and efficacy in the treatment of acute and subacute femoropopliteal bypass occlusions.Materials and MethodsForty-two patients (average age 65.8 {+-} 9.1 years) with acute (<14 days [n = 31]) and subacute (14-42 days [n = 11]) femoropopliteal bypass occlusions were treated consecutively with a rotational debulking and removal catheter (Straub Rotarex). The average occlusion length was 28.4 {+-} 2.9 (24-34) cm. Thirty-four (81 %) patients underwent venous bypass, and 8 (19 %) patients underwent polytetrafluoroethylene bypass.ResultsThe technical success rate was 97.6 % (41 of 42). In 1 patient, blood flow could not be restored despite the use of the atherothrombectomy system. The average catheter intervention time was 6.9 {+-} 2.1 (4-9) min. Ankle-brachial index increased from 0.39 {+-} 0.13 to 0.83 {+-} 0.11 at discharge and to 0.82 {+-} 0.17 after 1 month (p < 0.05). There were a total of 2 (4.8 %) peri-interventional complications: One patient developed a distal embolism, which was successfully treated with local lysis, and another patient had a small perforation at the distal anastomosis, which was successfully treated with a stent.ConclusionPMT with the Rotarex atherothrombectomy catheter represents a safe and effective option in the treatment of acute and subacute femoropopliteal bypass occlusions because it can quickly restore blood flow.

  9. [Effects and mechanisms of inorganic anions in water on degradation of LAS by UV/H2 O2 combination process].

    PubMed

    Pan, Jing; Sun, Tie-Heng; Li, Hai-Bo

    2007-11-01

    Experiments are carried out to study the effects and mechanisms of inorganic anions in water on the degradation of linear alkyl benzene sulfonate (LAS) in UV/H2 O2 process. The results show that UV/H2 O2 process could remove LAS effectively, and the rate of photodegradation follows first-order reaction kinetics model. Under the condition that H2 O2 concentration was 8 mg x L(-1) and a 14 W low pressure mercury vapor discharge lamp irradiated samples, the first-order photodegradation rate constant of LAS in distilled water and tap water were 0.018 0 min(-1) and 0.012 2 min(-1) respectively. NO3-, Cl-, SO4(2-) and HCO3- have inhibitory action on LAS photodegradation. The higher inorganic anions concentration was, the stronger inhibitory action. When their concentrations were 5, 10 and 15 mmol x L(-1) respectively, their inhibitory action order was HCO3- > NO3- > Cl- > SO4(2-) all the time. It was anions synthetical effect that caused photodegradation rate constant of LAS in tap water lower than distilled water.

  10. Feeling safe in the plane: neural mechanisms underlying superior action control in airplane pilot trainees – a combined EEG/MRS study

    PubMed Central

    Dharmadhikari, Shalmali; Chmielewski, Witold; Glaubitz, Benjamin; Schmidt-Wilcke, Tobias; Edden, Richard; Dydak, Ulrike; Beste, Christian

    2015-01-01

    In day-to-day life, we need to apply strategies to cascade different actions for efficient unfolding of behaviour. While deficits in action cascading are examined extensively, almost nothing is known about the neuronal mechanisms mediating superior performance above the normal level. To examine this question, we investigate action control in airplane pilot trainees. We use a stop-change paradigm that is able to estimate the efficiency of action cascading on the basis of mathematical constraints. Behavioural and EEG data is analyzed along these constraints and integrated with neurochemical data obtained using Magnetic Resonance Spectroscopy (MRS) from the striatal gamma-aminobutyric acid (GABA) -ergic system. We show that high performance in action cascading, as exemplified in airplane pilot trainees, can be driven by intensified attentional processes, circumventing response selection processes. The results indicate that the efficiency of action cascading and hence the speed of responding as well as attentional gating functions are modulated by striatal GABA and Glutamate + Glutamine concentrations. In superior performance in action cascading similar increases in the concentrations of GABA and Glutamate + Glutamine lead to stronger neurophysiological and behavioural effects as compared to subjects with normal performance in action cascading. PMID:24753040

  11. Mechanism analysis on finishing of reaction-sintered silicon carbide by combination of water vapor plasma oxidation and ceria slurry polishing

    NASA Astrophysics Data System (ADS)

    Shen, Xinmin; Tu, Qunzhang; Deng, Hui; Jiang, Guoliang; Yamamura, Kazuya

    2015-05-01

    Reaction-sintered silicon carbide (RS-SiC), which is considered as a promising mirror material for space telescope systems, requires a high surface property. An ultrasmooth surface with a Ra surface roughness of 0.480 nm was obtained after water vapor plasma oxidation for 90 min followed by ceria slurry polishing for 40 min. The oxidation process of RS-SiC by water vapor plasma was analyzed based on the Deal-Grove model, and the theoretical calculation results are consistent with the measured data obtained by scanning white light interferometer (SWLI), scanning electron microscopy/energy-dispersive