mechanical barrier
Recently Published Documents


TOTAL DOCUMENTS

151
(FIVE YEARS 52)

H-INDEX

26
(FIVE YEARS 7)

2021 ◽  
Author(s):  
Thomas J Bruce ◽  
Arild F Stein

Abstract Objectives/Scope Verification and testing of a wellbore barrier, in older assets has proven to be challenging. Even more so when the well has structural issues, indemnities or weak spots in the barrier envelope, that limits the possibility to get a positive pressure verification of the barrier with an applied surface pressure. The paper will air on the operational use of this novel test method and the tools used, to allow an in well verification of any type of barrier to secure the well for a repair or a upcoming P/A operation. A pilot job case history will be included to illustrate use of the principles. Methods, Procedures, Process Find a suitable location with necessary support and strength in the well. If installing a mechanical barrier by means of a bridge plug as the primary barrier, we will monitor the installation forces in the anchoring and sealing sequence. This individual signature will be verified towards a nominal base line signature towards a library of thousands of collected installation profiles. Any abnormality can trigger a release and possible relocating of the barrier. A second verification barrier will then be installed above the primary barrier. When both installation signatures are accounted for, we can pressure test the installed barriers. This is done with a pressure inflow tool, where we introduce a calculated predetermined pressure drop between the installed primary barrier and the verification barrier. By monitoring this pressure alteration vs. the pressure above the verification barrier, we can determine if we have a verified barrier. Results, Observations, Conclusions We now have the Primary Barrier verified in the direction of flow (negative pressure test). And verification barrier as the secondary barrier (verified with a positive pressure test). If a dual barrier is requested, you can leave the verification barrier as secondary barrier. Novel/Additional Information Pressure manipulation is done with existing and proven technology and is re-usable after re-setting at surface. By monitoring this pressure alteration, we can verify the installed primary and verification barrier in one run. This without any time-consuming pressure manipulating from surface.


2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Shanshan Chen ◽  
Chi Zhang ◽  
Beihui He ◽  
Ruonan He ◽  
Li Xu ◽  
...  

lncRNA is a transcript that is more than 200 bp in length. Currently, evidence has shown that lncRNA is of great significance in cell activity, involved in epigenetics, gene transcription, chromatin regulation, etc. The existence of an intestinal mucosal mechanical barrier hinders the invasion of pathogenic bacteria and toxins, maintaining the stability of the intestinal environment. Serious destruction or dysfunction of the mechanical barrier often leads to intestinal diseases. This review first summarizes the ability of lncRNAs to regulate the intestinal mucosal mechanical barrier. We then discussed how lncRNAs participate in various intestinal diseases by regulating the intestinal mucosal mechanical barrier. Finally, we envision its potential as a new marker for diagnosing and treating intestinal inflammatory diseases.


2021 ◽  
Vol 9 (D) ◽  
pp. 279-284
Author(s):  
Ismet Danial Nasution ◽  
Haslinda Z. Tamin ◽  
Ariyani Ariyani ◽  
Ivana Ivana

BACKGROUND: One of the properties of the soft denture lining (SDL) material that needed to overcome the functional problems is softness. Loss of softness due to the aging process and to extend the duration of use, sealer coating was developed to maintain its softness. Sealer coating acts as mechanical barrier to provide protection against aging of SDL materials. AIM: This study aims to determine the influence of thermocycling and sealer coating application on the shore hardness of the acrylic-based and silicone-based auto-polymerizing soft denture lining materials. MATERIALS AND METHODS: Materials that were used in this study are acrylic-based auto-polymerizing SDL (Durabase Soft, Reliance Dental Manufacturing LLC, Illinois, USA) and silicone-based auto-polymerizing SDL (Mollosil, Detax GmbH, Ettlingen, Germany). In this study, we used monopoly as sealer coating for acrylic-based auto-polymerizing SDL and varnish for silicone-based auto-polymerizing SDL. Thermocycling was performed for 2000 cycles for a 2-year simulation time. For shore hardness test, a total of 40 discs shaped samples were made with a diameter of 35 mm and a thickness of 6 mm. The samples were divided into eight groups (n = 5), namely, the uncoated and non-thermocycling acrylic-based auto-polymerizing SDL, the coated and non-thermocycling acrylic-based auto-polymerizing SDL, the uncoated and thermocycling acrylic-based auto-polymerizing SDL, the coated and thermocycling acrylic-based auto-polymerizing SDL, the uncoated and non-thermocycling silicone-based auto-polymerizing SDL, the coated and non-thermocycling silicone-based auto-polymerizing SDL, the uncoated and thermocycling silicone-based auto-polymerizing SDL, and the coated and thermocycling silicone-based auto-polymerizing SDL. The hardness test was carried out using the shore A durometer. RESULTS: The obtained data were tested using the independent t-test with a significance level of p < 0.05. The results showed that there was a significant effect between coated and uncoated acrylic-based SDL group that underwent thermocycling and in the silicone-based SDL group. The study showed that the hardness value was lower in both coated acrylic-based and silicone-based SDL groups compared to the non-coated group, so it can be concluded that the sealer coating is able to protect the hardness of SDL material against aging with a thermocycling simulation. The results also showed that there was a significant effect of thermocycling on the hardness of the material both in the coated acrylic-based SDL group, the uncoated acrylic-based SDL group, and the uncoated silicone-based SDL group. Study also showed that there was no significant effect of thermocycling in the coated silicone-based SDL group. CONCLUSION: Based on the results, it can be concluded that the use of sealer coating can maintain the hardness properties of both acrylic-based SDL and silicon-based self-polymerizing SDL so that it can increase the durability of SDL materials. However, the effect of sealer coating in protecting the hardness of SDL materials against aging was more evident in the silicone-based SDL group.


Author(s):  
Ragavanantham Shanmugam ◽  
Vishnuvarthanan Mayakrishnan ◽  
Radhakrishnan Kesavan ◽  
Kirubanandan Shanmugam ◽  
Subha Veeramani ◽  
...  

2021 ◽  
Author(s):  
Ragavanantham Shanmugam ◽  
Vishnuvarthanan Mayakrishnan ◽  
Radhakrishnan Kesavan ◽  
Kirubanandan Shanmugam ◽  
Subha Veeramani ◽  
...  

Abstract In this study, an environmentally friendly and biodegradable pullulan/graphene bio nanocomposite was prepared and coated on the nanocellulose film to improve the surface, mechanical, barrier and antibacterial properties. The nanocellulose films were prepared by using a spray coating of nanocellulose suspension on stainless steel plates. The graphene nanoparticles were prepared by the modified Hummers method. The pullulan/graphene bio nanocomposites were prepared by solvent method with the addition of various wt% (0, 0.05, 0.1, 0.2) of graphene with pullulan. The coating was carried out by the roller coating method. Results showed that the increased graphene nanoparticles in pullulan coating increased the opacity, surface hydrophobicity, tensile strength, oxygen transmission rate and watervapour transmission rate of the coated nanocellulose film. Also, the coated film showed excellent antibacterial properties against both gram-negative E.coli and gram-positive S.aureus. In this research work, it was concluded that the graphene nanoparticles of 0.2 wt% showed efficient results. The exceptional properties of the pullulan/graphene bio nanocomposite coating on the nanocellulose film will give a new pathway to high performance food packaging applications.


2021 ◽  
Vol 12 ◽  
Author(s):  
Yuhua He ◽  
Jiaqi Chen ◽  
Qiyue Zhang ◽  
Jialong Zhang ◽  
Lulai Wang ◽  
...  

α-Chaconine is the most abundant glycoalkaloid in potato and toxic to the animal digestive system, but the mechanisms underlying the toxicity are unclear. In this study, mouse small intestinal epithelial cells were incubated with α-chaconine at 0, 0.4, and 0.8 μg/mL for 24, 48, and 72 h to examine apoptosis, mechanical barrier function, and antioxidant ability of the cells using a cell metabolic activity assay, flow cytometry, Western blot, immunofluorescence, and fluorescence quantitative PCR. The results showed that α-chaconine significantly decreased cell proliferation rate, increased apoptosis rate, decreased transepithelial electrical resistance (TEER) value, and increased alkaline phosphatase (AKP) and lactate dehydrogenase (LDH) activities, and there were interactions between α-chaconine concentration and incubation time. α-Chaconine significantly reduced the relative and mRNA expressions of genes coding tight junction proteins zonula occludens-1 (ZO-1) and occludin, increased malondialdehyde (MDA) content, decreased total glutathione (T-GSH) content, reduced the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and γ-glutamylcysteine synthetase (γ-GCS) and the mRNA expressions of SOD, CAT, GSH-Px, and γ-GCS genes. In conclusion, α-chaconine disrupts the cell cycle, destroys the mechanical barrier and permeability of mucosal epithelium, inhibits cell proliferation, and accelerates cell apoptosis.


Author(s):  
Jamie A. Davies

This chapter describes how the human body protects its internal conditions against micro-organisms and the environment. The body’s first line of defence is the mechanical barrier provided by the skin, a part of the integumentary system. When the integument is breached, the body’s immediate priority is to seal the hole by coagulation of the leaking blood. The next line of defence is chemical: the secretions that cover the surfaces of eyes and the inside of the nose contain a variety of proteins that attack bacteria. Within the blood and fluids that bathe internal tissues are proteins of the complement system. The chapter then considers the innate and the adaptive immune systems.


Sign in / Sign up

Export Citation Format

Share Document