Adhesion and Electrical Insulation of Thin Polymeric Coatings Under Saline Exposure

1987 ◽  
Vol 110 ◽  
Author(s):  
R. N. Leyden ◽  
D. I. Basiulis
Keyword(s):  
Barrier Properties ◽  
Peel Strength ◽  
Polymer Coatings ◽  
Polymeric Coatings ◽  
Adhesive Failure ◽  
Short Term ◽  
Leakage Currents ◽  
Electrical Bias ◽  
Implanted Devices

AbstractA study was made of the adhesion of insulating polymer coatings under long term exposure to electrical bias. Since a common mode of failure in implanted devices is the penetration of water into poorly adhering insulation/conductor interfaces followed by electrolytic degradation, development of processes, primers, and insulators with good adhesion that resist the effects of water were sought. Polyimide coatings were tested for their ion barrier properties by immersion of insulated comb patterns in saline with 9 V D.C. bias between the comb fingers. Leakage currents, measured over three years exposure, increased from several picoamps initially to several nanoamps in surviving specimens. Subsequent studies showed that dramatic improvements in the moisture durability of the adhesion could be obtained using Hitachi's aluminum chelate type primer. Whereas the peel strength of polyimide on unprimed platinum fell more than 90% after several hours of boiling saline exposure, the peel strength of polyimide coatings on primed surfaces remained at over 80% of their initial values. ESCA analysis of the peel interfaces showed that both aluminum oxide and polyimide remain on the substrate after peeling back the polyimide. This suggests a combination of cohesive and adhesive failure at the primer/polyimide interface. The effects of exposure of the polymer/substrate interfaces (edges) to saline and electrochemical stress were examined by patterning circular openings in the polyimide. A 10 V anodic potential was found to damage adhesion to titanium as far as 75 microns away from the edge. Pulsing at 500 Hz, 1 V peak to peak was found to have no measurable effect in the short term.

Bi-Polar Synaptic Behavior of Pt/SiOx:Ag/TiOx/p++- Si Memristor

2020 ◽  
Vol 984 ◽  
pp. 104-109
Author(s):  
Yu Han Yuan ◽  
Nasir Ilyas ◽  
Zhi Hui Qi ◽  
Dong Yang Li ◽  
Xiang Dong Jiang ◽  
...  
Keyword(s):  
Thin Layer ◽  
Short Term Memory ◽  
Long Term Memory ◽  
Short Term ◽  
Memristive Device ◽  
Term Memory ◽  
Synaptic Functions ◽  
Term Potentiation ◽  
Electrical Bias

Recently, by inserting a TiOx thin layer, we have fabricated a memristive device as Pt/SiOx:Ag/TiOx/p++-Si which features a better bi-polar gradually resistive switching under positive and negative electrical bias. Different synaptic functions including potentiation, depression, short-term potentiation and the transition from short-term memory (STM) to long-term memory (LTM) using suitably programmed voltage pulse have been implemented successfully in the memristive device. It is indicated that the Pt/SiOx:Ag/TiOx/p++-Si memristor can be used as a promising emulator for biological synapse, which could have great potential for brain-inspired neuromorphic computing.

scholarly journals Inhibition of Protein Prenylation of GTPases Alters Endothelial Barrier Function

2019 ◽  
Vol 21 (1) ◽  
pp. 2 ◽  
Author(s):  
Muhammad Aslam ◽  
Christian Troidl ◽  
Christian Tanislav ◽  
Susanne Rohrbach ◽  
Dursun Gündüz ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Barrier Function ◽  
Barrier Properties ◽  
Term Treatment ◽  
Endothelial Barrier ◽  
Protein Prenylation ◽  
Short Term ◽  
Long Term Treatment ◽  
Biphasic Effect

The members of Rho family of GTPases, RhoA and Rac1 regulate endothelial cytoskeleton dynamics and hence barrier integrity. The spatial activities of these GTPases are regulated by post-translational prenylation. In the present study, we investigated the effect of prenylation inhibition on the endothelial cytoskeleton and barrier properties. The study was carried out in human umbilical vein endothelial cells (HUVEC) and protein prenylation is manipulated with various pharmacological inhibitors. Inhibition of either complete prenylation using statins or specifically geranylgeranylation but not farnesylation has a biphasic effect on HUVEC cytoskeleton and permeability. Short-term treatment inhibits the spatial activity of RhoA/Rho kinase (Rock) to actin cytoskeleton resulting in adherens junctions (AJ) stabilization and ameliorates thrombin-induced barrier disruption whereas long-term inhibition results in collapse of endothelial cytoskeleton leading to increased basal permeability. These effects are reversed by supplementing the cells with geranylgeranyl but not farnesyl pyrophosphate. Moreover, long-term inhibition of protein prenylation results in basal hyper activation of RhoA/Rock signaling that is antagonized by a specific Rock inhibitor or an activation of cAMP signaling. In conclusion, inhibition of geranylgeranylation in endothelial cells (ECs) exerts biphasic effect on endothelial barrier properties. Short-term inhibition stabilizes AJs and hence barrier function whereas long-term treatment results in disruption of barrier properties.

Conceptual short-term memory (CSTM) supports core claims of Christiansen and Chater

2016 ◽  
Vol 39 ◽  
Author(s):  
Mary C. Potter
Keyword(s):  
Working Memory ◽  
Rapid Serial Visual Presentation ◽  
Language Comprehension ◽  
Short Term Memory ◽  
Visual Presentation ◽  
Long Term Memory ◽  
Short Term ◽  
Term Memory ◽  
Use Of Knowledge

AbstractRapid serial visual presentation (RSVP) of words or pictured scenes provides evidence for a large-capacity conceptual short-term memory (CSTM) that momentarily provides rich associated material from long-term memory, permitting rapid chunking (Potter 1993; 2009; 2012). In perception of scenes as well as language comprehension, we make use of knowledge that briefly exceeds the supposed limits of working memory.

Ultrastructural investigations of MDL 19,660-induced effects on the canine platelet and megakaryocyte

1990 ◽  
Vol 48 (3) ◽  
pp. 374-375
Author(s):  
D.E. Loudy ◽  
J. Sprinkle-Cavallo ◽  
J.T. Yarrington ◽  
F.Y. Thompson ◽  
J.P. Gibson
Keyword(s):  
Antidepressant Drug ◽  
Beagle Dogs ◽  
Long Term Effects ◽  
Short Term ◽  
Platelet Counts ◽  
Toxicological Studies ◽  
Induced Aggregation ◽  
Internal Architecture

Previous short term toxicological studies of one to two weeks duration have demonstrated that MDL 19,660 (5-(4-chlorophenyl)-2,4-dihydro-2,4-dimethyl-3Hl, 2,4-triazole-3-thione), an antidepressant drug, causes a dose-related thrombocytopenia in dogs. Platelet counts started to decline after two days of dosing with 30 mg/kg/day and continued to decrease to their lowest levels by 5-7 days. The loss in platelets was primarily of the small discoid subpopulation. In vitro studies have also indicated that MDL 19,660: does not spontaneously aggregate canine platelets and has moderate antiaggregating properties by inhibiting ADP-induced aggregation. The objectives of the present investigation of MDL 19,660 were to evaluate ultrastructurally long term effects on platelet internal architecture and changes in subpopulations of platelets and megakaryocytes.Nine male and nine female beagle dogs were divided equally into three groups and were administered orally 0, 15, or 30 mg/kg/day of MDL 19,660 for three months. Compared to a control platelet range of 353,000- 452,000/μl, a doserelated thrombocytopenia reached a maximum severity of an average of 135,000/μl for the 15 mg/kg/day dogs after two weeks and 81,000/μl for the 30 mg/kg/day dogs after one week.

Comparison of Auditory, Language, Memory, and Attention Abilities in Children With and Without Listening Difficulties

2020 ◽  
Vol 29 (4) ◽  
pp. 710-727
Author(s):  
Beula M. Magimairaj ◽  
Naveen K. Nagaraj ◽  
Alexander V. Sergeev ◽  
Natalie J. Benafield
Keyword(s):  
Auditory Processing ◽  
Short Term Memory ◽  
Group Differences ◽  
Long Term Memory ◽  
Short Term ◽  
Significant Group ◽  
Term Memory ◽  
Memory And Attention ◽  
Speed And Accuracy

Objectives School-age children with and without parent-reported listening difficulties (LiD) were compared on auditory processing, language, memory, and attention abilities. The objective was to extend what is known so far in the literature about children with LiD by using multiple measures and selective novel measures across the above areas. Design Twenty-six children who were reported by their parents as having LiD and 26 age-matched typically developing children completed clinical tests of auditory processing and multiple measures of language, attention, and memory. All children had normal-range pure-tone hearing thresholds bilaterally. Group differences were examined. Results In addition to significantly poorer speech-perception-in-noise scores, children with LiD had reduced speed and accuracy of word retrieval from long-term memory, poorer short-term memory, sentence recall, and inferencing ability. Statistically significant group differences were of moderate effect size; however, standard test scores of children with LiD were not clinically poor. No statistically significant group differences were observed in attention, working memory capacity, vocabulary, and nonverbal IQ. Conclusions Mild signal-to-noise ratio loss, as reflected by the group mean of children with LiD, supported the children's functional listening problems. In addition, children's relative weakness in select areas of language performance, short-term memory, and long-term memory lexical retrieval speed and accuracy added to previous research on evidence-based areas that need to be evaluated in children with LiD who almost always have heterogenous profiles. Importantly, the functional difficulties faced by children with LiD in relation to their test results indicated, to some extent, that commonly used assessments may not be adequately capturing the children's listening challenges. Supplemental Material https://doi.org/10.23641/asha.12808607

Abstract #283 Diabetes Increases Short-Term but not Long-Term Risk of Fracture: A Community-Based Study

2019 ◽  
Vol 25 ◽  
pp. 114
Author(s):  
Alyssa Dufour ◽  
Setareh Williams ◽  
Richard Weiss ◽  
Elizabeth Samelson
Keyword(s):  
Short Term ◽  
Community Based ◽  
Risk Of Fracture

Abstract #238: Improved Short Term and Long Term Outcomes of Early Insulin Initiation in Type 2 Diabetes Over 10 Years

2017 ◽  
Vol 23 ◽  
pp. 50
Author(s):  
Jothydev Kesavadev ◽  
Shashank Joshi ◽  
Banshi Saboo ◽  
Hemant Thacker ◽  
Arun Shankar ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Insulin Initiation ◽  
Long Term Outcomes ◽  
Short Term

Anticoagulation in addition to dual antiplatelet therapy has no impact on long-term follow-up after endovascular treatment of (sub)acute lower limb ischemia

VASA ◽  
2019 ◽  
Vol 48 (4) ◽  
pp. 321-329
Author(s):  
Mariya Kronlage ◽  
Erwin Blessing ◽  
Oliver J. Müller ◽  
Britta Heilmeier ◽  
Hugo A. Katus ◽  
...  
Keyword(s):  
Endovascular Treatment ◽  
Antiplatelet Therapy ◽  
Dual Antiplatelet Therapy ◽  
Limb Ischemia ◽  
Bleeding Complications ◽  
Severe Bleeding ◽  
Short Term ◽  
Long Term Follow Up

Summary. Background: To assess the impact of short- vs. long-term anticoagulation in addition to standard dual antiplatelet therapy (DAPT) upon endovascular treatment of (sub)acute thrombembolic occlusions of the lower extremity. Patient and methods: Retrospective analysis was conducted on 202 patients with a thrombembolic occlusion of lower extremities, followed by crirical limb ischemia that received endovascular treatment including thrombolysis, mechanical thrombectomy, or a combination of both between 2006 and 2015 at a single center. Following antithrombotic regimes were compared: 1) dual antiplatelet therapy, DAPT for 4 weeks (aspirin 100 mg/d and clopidogrel 75 mg/d) upon intervention, followed by a lifelong single antiplatelet therapy; 2) DAPT plus short term anticoagulation for 4 weeks, followed by a lifelong single antiplatelet therapy; 3) DAPT plus long term anticoagulation for > 4 weeks, followed by a lifelong anticoagulation. Results: Endovascular treatment was associated with high immediate revascularization (> 98 %), as well as overall and amputation-free survival rates (> 85 %), independent from the chosen anticoagulation regime in a two-year follow up, p > 0.05. Anticoagulation in addition to standard antiplatelet therapy had no significant effect on patency or freedom from target lesion revascularization (TLR) 24 months upon index procedure for both thrombotic and embolic occlusions. Severe bleeding complications occurred more often in the long-term anticoagulation group (9.3 % vs. 5.6 % (short-term group) and 6.5 % (DAPT group), p > 0.05). Conclusions: Our observational study demonstrates that the choice of an antithrombotic regime had no impact on the long-term follow-up after endovascular treatment of acute thrombembolic limb ischemia whereas prolonged anticoagulation was associated with a nominal increase in severe bleeding complications.

Intraindividual Variability and Stability of Affect and Well-Being

GeroPsych ◽  
2013 ◽  
Vol 26 (3) ◽  
pp. 185-199 ◽  
Author(s):  
Christina Röcke ◽  
Annette Brose
Keyword(s):  
Age Differences ◽  
Well Being ◽  
Subjective Well Being ◽  
Emotional Experiences ◽  
Short Term ◽  
Regulatory Processes ◽  
Functional Implications ◽  
Methodological Approaches ◽  
Underlying Processes

Whereas subjective well-being remains relatively stable across adulthood, emotional experiences show remarkable short-term variability, with younger and older adults differing in both amount and correlates. Repeatedly assessed affect data captures both the dynamics and stability as well as stabilization that may indicate emotion-regulatory processes. The article reviews (1) research approaches to intraindividual affect variability, (2) functional implications of affect variability, and (3) age differences in affect variability. Based on this review, we discuss how the broader literature on emotional aging can be better integrated with theories and concepts of intraindividual affect variability by using appropriate methodological approaches. Finally, we show how a better understanding of affect variability and its underlying processes could contribute to the long-term stabilization of well-being in old age.

Sign in / Sign up

Export Citation Format

Share Document