scholarly journals Chemical stability of oil-infused polyethylene

2020 ◽  
pp. 088532822097735
Author(s):  
Fedra P Zaribaf ◽  
Harinderjit S Gill ◽  
Elise C Pegg
Keyword(s):  
Vitamin E ◽  
Chemical Stability ◽  
Antioxidant Properties ◽  
Oxidation Stability ◽  
Thermal Ageing ◽  
Similar Process ◽  
Mechanical Degradation ◽  
Suitable Material ◽  
Thermally Treated

Ultra-high molecular weight polyethylene (UHMWPE) can be made radiopaque for medical imaging applications through the diffusion of an iodised oil-based contrast agent (Lipiodol Ultra Fluid). A similar process is used for Vitamin E incorporated polyethylene which provides antioxidant properties. This study aimed to investigate the critical long-term properties of oil-infused medical polyethylene after 4 weeks of accelerated thermal ageing. Samples treated with an oil (Vitamin E or Lipiodol) had a higher oxidation stability than currently used medical grade polyethylene, indicated by a smaller increase in oxidation index after ageing (Vitamin E + 36%, Lipiodol +40%, Untreated +136%, Thermally treated +164%). The tensile properties of oil treated polyethylene after ageing were significantly higher than the Untreated and Thermally treated controls (p<0.05) indicating less mechanical degradation. There was also no alteration in the percentage crystallinity of oil treated samples after ageing, though the radiopacity of the Lipiodol treated samples reduced by 54% after ageing. The leaching of oil with time was also investigated; the leaching of Lipiodol and Vitamin E followed the same trend and reached a steady state by two weeks. Overall, it can be concluded that the diffusion of an oil-based fluid into polyethylene not only increases the oxidative and chemical stability of polyethylene but also adds additional functionality (e.g. radiopacity) providing a more suitable material for long–term medical applications.

Epoxy Resin Exhibits Long-Term Durability and Chemical Stability as a Well Sealant

2021 ◽  
Author(s):  
Fred Sabins ◽  
Allen Apblett ◽  
Randall Shafer ◽  
Larry Watters
Keyword(s):  
Epoxy Resin ◽  
Fresh Water ◽  
Chemical Stability ◽  
Elevated Temperatures ◽  
Mechanical Degradation ◽  
Gravimetric Analysis ◽  
Degradation Reactions ◽  
Temperature Ranges ◽  
One Year

Abstract The necessity to verify epoxy resin sealant's reliability for well applications is amplified as its use increases. Limited data exists to confirm resin's long-term durability or chemical stability under exposure to well fluids at temperature and pressure. This paper presents laboratory results illustrating durability and stability of epoxy resin exposed to a range of well fluids over a span of temperatures. Additionally, results of accelerated thermal degradation testing further quantify long-term thermal and chemical stability. Epoxy resins formulated for a range of remedial and abandonment applications were cured in fresh water, CaCl2 brine, and hydrocarbon at 170°F up to one year. Additional samples cured in fresh water and water containing CO2 and H2S at elevated temperatures (220°F to 320°F) for up to six weeks to produce accelerated degradation reactions allowed the assessment of resin degradation verses temperature. Thermal Gravimetric Analysis (TGA) evaluated chemical and mechanical degradation verses time at temperatures ranging from 200°C to 400°C. Arrhenius calculations were performed to forecast long term stability of resins across their intended temperature ranges. Resulting data were analyzed to develop an inclusive assessment of resin stability and durability in well environments. Results indicate properly formulated epoxy resin is a mechanically, chemically, and thermally durable sealant for well applications.

scholarly journals Effect of zinc supplementation on in vitro copper-induced oxidation of low-density lipoproteins in healthy French subjects aged 55–70 years:the Zenith Study

2006 ◽  
Vol 95 (6) ◽  
pp. 1134-1142 ◽  
Author(s):  
Christine Feillet-Coudray ◽  
Nathalie Meunier ◽  
Dominique Bayle ◽  
Marion Brandolini-Bunlon ◽  
Maud Andriollo-Sanchez ◽  
...  
Keyword(s):  
Vitamin E ◽  
Healthy Subjects ◽  
Antioxidant Properties ◽  
Ldl Oxidation ◽  
Controlled Study ◽  
Dietary Intakes ◽  
Conjugated Diene ◽  
Double Blind

Zn has been shown to possess antioxidant properties in vitro and in vitro. As inadequate dietary Zn intake has been reported in these populations, Zn supplementation may protect against oxidative stress and thereby limit the progression of degenerative diseases in such populations. We conducted the present study to evaluate the long-term supplementation effects of two moderate doses of Zn on in vitro Cu-induced LDL oxidation in French men and women.Three groups of sixteen healthy subjects aged 55–70 years from each sex participated in this randomized double-blind, placebo-controlled study. Each group received for six months either 0, 15 or 30mg supplemental Zn per d. At the beginning and at the end of the supplementation periods, dietary intakes of Zn, Cu, Fe and vitamin E were estimated using 4d food-intake records (including the weekend) and the GENI program. Zn, Cu, Fe and vitamin E statuswere also determined. In vitro LDL oxidizability (basal conjugated diene level, maximal conjugated diene formation and lag time) and lipid parameters were also determined. Dietary intakes of Zn, Cu, Fe and vitamin E were adequate in this population. Zn supplementation significantly increased serum Zn levels but did not significantly modify Cu, Fe or vitamin E status. However, Zn supplementation had no effect on in vitro LDL oxidation parameters, nor were there any sex-related differences in in vitro LDL oxidizability. The present study showed that long-term Zn supplementation of healthy subjects aged 55–70 years had no effect on in vitro Cu-induced LDL oxidation under the study conditions.

scholarly journals Role of Vitamin E and the Orexin System in Neuroprotection

2021 ◽  
Vol 11 (8) ◽  
pp. 1098
Author(s):  
Maria Ester La Torre ◽  
Ines Villano ◽  
Marcellino Monda ◽  
Antonietta Messina ◽  
Giuseppe Cibelli ◽  
...  
Keyword(s):  
Vitamin E ◽  
Neurodegenerative Diseases ◽  
Antioxidant Properties ◽  
Phenotypic Change ◽  
The Central Nervous System ◽  
Specific Receptors

Microglia are the first line of defense at the level of the central nervous system (CNS). Phenotypic change in microglia can be regulated by various factors, including the orexin system. Neuroinflammation is an inflammatory process mediated by cytokines, by the lack of interaction of specific receptors such as the OX2-OX2R complex, caused by systemic tissue damage or, more often, associated with direct damage to the CNS. Chronic activation of microglia could lead to long-term neurodegenerative diseases. This review aims to explore how tocopherol (vitamin E) and the orexin system may play a role in the prevention and treatment of microglia inflammation and, consequently, in neurodegenerative diseases thanks to its antioxidant properties. The results of animal and in vitro studies provide evidence to support the use of tocopherol for a reduction in microglia inflammation as well as a greater activation of the orexinergic system. Although there is much in vivo and in vitro evidence of vitamin E antioxidant and protective abilities, there are still conflicting results for its use as a treatment for neurodegenerative diseases that speculate that vitamin E, under certain conditions or genetic predispositions, can be pro-oxidant and harmful.

scholarly journals Long-Term Pharmacologic Doses of Vitamin E Only Moderately Affect the Erythrocytes of Patients with Type 1 Diabetes Mellitus

2001 ◽  
Vol 131 (6) ◽  
pp. 1723-1730 ◽  
Author(s):  
Begoña Manuel y Keenoy ◽  
Honglei Shen ◽  
Wendy Engelen ◽  
Jan Vertommen ◽  
Guido Van Dessel ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Type 1 Diabetes ◽  
Vitamin E ◽  
Type 1 Diabetes Mellitus

scholarly journals Nutritional Status in Spanish Adults with Celiac Disease Following a Long-Term Gluten-Free Diet Is Similar to Non-Celiac

Nutrients ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 1626
Author(s):  
Catalina Ballestero-Fernández ◽  
Gregorio Varela-Moreiras ◽  
Natalia Úbeda ◽  
Elena Alonso-Aperte
Keyword(s):  
Bone Mineral Density ◽  
Vitamin D ◽  
Celiac Disease ◽  
Vitamin E ◽  
Nutritional Status ◽  
Bone Mineral ◽  
Biochemical Parameters ◽  
Gluten Free ◽  
Mineral Density

The only available treatment for celiac disease is life-long gluten exclusion. We conducted a cross-sectional age- and gender-matched study in 64 celiac adults on a long-term (>1 year) gluten-free diet and 74 non-celiac volunteers from Spain, using dietary, anthropometric, and biochemical parameters, as well as assessing bone mineral density and physical activity. Celiac adults had deficient intake (below 2/3 of the recommended intake) for folates, vitamin E, and iodine and low intake of calcium (below 80% of the recommended intake). Iron intake was also below 2/3 of the recommended intake in celiac women. Vitamin D intake was extremely low, and 34% of celiac patients had moderately deficient plasma levels. According to bone mineral density, celiac women may be more prone to osteopenia and osteoporosis. However, we found a perfectly analogous nutritional status scenario in celiac as compared to healthy volunteers, with the dietary deviations found being similar to those of the Spanish population, i.e., both groups followed a high-lipid, high-protein, and low-carbohydrate diet. Values for biochemical parameters were found within the reference ranges. Celiac disease had no influence on body weight, but body fat in celiac patients tended to be higher. According to our results, vitamin D, calcium, folates, vitamin E, iodine, and iron nutritional status should be specifically assessed and monitored in the celiac population.

scholarly journals Electrospun PCL Patches with Controlled Fiber Morphology and Mechanical Performance for Skin Moisturization via Long-Term Release of Hemp Oil for Atopic Dermatitis

Membranes ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 26
Author(s):  
Sara Metwally ◽  
Daniel P. Ura ◽  
Zuzanna J. Krysiak ◽  
Łukasz Kaniuk ◽  
Piotr K. Szewczyk ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Atopic Dermatitis ◽  
Mechanical Performance ◽  
Antibacterial Properties ◽  
Skin Condition ◽  
Fiber Morphology ◽  
Suitable Material ◽  
Hemp Oil ◽  
Skin Moisture

Atopic dermatitis (AD) is a chronic, inflammatory skin condition, caused by wide genetic, environmental, or immunologic factors. AD is very common in children but can occur at any age. The lack of long-term treatments forces the development of new strategies for skin regeneration. Polycaprolactone (PCL) is a well-developed, tissue-compatible biomaterial showing also good mechanical properties. In our study, we designed the electrospun PCL patches with controlled architecture and topography for long-term release in time. Hemp oil shows anti-inflammatory and antibacterial properties, increasing also the skin moisture without clogging the pores. It can be used as an alternative cure for patients that do not respond to traditional treatments. In the study, we tested the mechanical properties of PCL fibers, and the hemp oil spreading together with the release in time measured on skin model and human skin. The PCL membranes are suitable material as patches or bandages, characterized by good mechanical properties and high permeability. Importantly, PCL patches showed release of hemp oil up to 55% within 6 h, increasing also the skin moisture up to 25%. Our results confirmed that electrospun PCL patches are great material as oil carriers indicating a high potential to be used as skin patches for AD skin treatment.

Long-Term Structural and Chemical Stability of Carbon Electrodes in Vanadium Redox Flow Battery

2021 ◽  
Author(s):  
Bhuvaneswari M. Sivakumar ◽  
Venkateshkumar Prabhakaran ◽  
Kaining Duanmu ◽  
Edwin Thomsen ◽  
Brian Berland ◽  
...  
Keyword(s):  
Chemical Stability ◽  
Vanadium Redox Flow Battery ◽  
Carbon Electrodes ◽  
Redox Flow Battery ◽  
Flow Battery ◽  
Vanadium Redox

Functionality and genomics of selenium and vitamin E supplementation in ruminants

2016 ◽  
Vol 56 (8) ◽  
pp. 1285 ◽  
Author(s):  
S. S. Chauhan ◽  
F. Liu ◽  
B. J. Leury ◽  
J. J. Cottrell ◽  
P. Celi ◽  
...  
Keyword(s):  
Vitamin E ◽  
Functional Foods ◽  
Transition Period ◽  
Animal Health ◽  
Antioxidant Properties ◽  
Meat Products ◽  
Lipid Hydroperoxides ◽  
Great Opportunity ◽  
Multiple Functions ◽  
Function Discovery

Selenium (Se) and vitamin E are essential micronutrients for animal health and production. The major function of both Se and vitamin E is to prevent the oxidative damage of biological membranes and they can influence growth, reproduction, immune function, health, and product quality in ruminants. Both Se and vitamin E are important for maintaining low cellular and systemic concentrations of reactive oxygen species and lipid hydroperoxides, to ensure optimum cellular function. Discovery of various selenoproteins and vitamin E-responsive genes has contributed significantly to improving our understanding about multiple functions of Se and vitamin E. There is evidence that these functions extend beyond the classical antioxidant properties to immunomodulation and intracellular cell signalling and gene regulation. Research in recent years has also shown that supranutritional supplementation of Se and vitamin E is required to improve the performance of ruminants under certain stressful conditions such as heat stress and during transition period. Considering the growing awareness among consumers of the benefits of antioxidant-rich food, there is a great opportunity for the livestock industries to focus on producing antioxidant-enriched milk and meat products or functional foods. The present review focuses on the recent developments in understanding multiple functions of Se and vitamin E at the cellular and molecular level and the effects of supranutritional supplementation on ruminant performance. In addition, the paper also articulates the potential opportunities to produce functional foods enriched with antioxidants, and underlines the need for optimum supplementation of these micronutrients for efficient ruminant production.

Sign in / Sign up

Export Citation Format

Share Document