Developing Superhydrophobic Coatings for Mitigating Aircraft Icing using Plasma Spray Processes

In-flight icing due to the presence of super-cooled water droplets is a major problem for aircraft operators. Accumulation of ice on the surface of wings, control parts and sensors can result in a range of problems including navigation issues, decreased efficiency, increasing fuel consumption, forced flight delays and cancelation and, if neglected or mismanaged, even fatal flight incidents. A significant potential solution for mitigating the icing problem is the use of superhydrophobic coatings i.e. coating that are extremely water repelling. Superhydrophobic coatings, by repelling the water droplets, can delay and in some cases prevent ice accumulation. Additionally, superhydrophobic coatings can facilitate ice removal by heating or vibration due to their non-stick properties. The superhydrophobicity of a surface is a result of the combination of the surface micro-texture and its surface energy which is determined by the chemistry of the surface. The major challenge facing the use of superhydrophobic coatings is the fact that low surface energy materials are mainly organic, polymeric compounds that suffer from poor durability, and in addition, micro-textured coatings are typically made by complex and expensive techniques. In this work atmospheric plasma spray (APS) and suspension plasma spray (SPS) which are flexible, scalable and efficient surface engineering techniques, are employed to develop micro-textured superhydrophobic coatings for anti-icing applications. In this research, APS and SPS TiO2 micro-textured coatings are developed. After treatment by a stearic acid solution in order to lower their surface energy, these coatings demonstrate hydrophobicity and superhydrophobicity to different extents. APS coatings that are produced using 10-80 micron-sized particle feedstock, although highly hydrophobic, lack the extreme water repellency known as water mobility, due to their relatively coarse micro-texture. In the SPS process, submicron-sized TiO2 particles in the form of a suspension are used as feedstock. The SPS coatings typically show superhydrophobicity with water contact angles higher than 150°. The coatings produced using an ethanol-based suspension demonstrated extreme hydrophobicity and a water droplet impacting on their surface bounces back and detaches from them easily. The parameters influencing the SPS process are further studied and optimized to achieve coatings with hierarchical surface micro-texture i.e. a surface with a primary micron-sized and a secondary submicron-sized micro-texture. After optimization of the process, the SPS TiO2 coatings show extreme superhydrophobicity with water contact angles as high as 170°, water sliding angles as small as 1.3° and a contact angle hysteresis as small as 4°. These superhydrophobic SPS TiO2 coatings demonstrate promising results in terms icing performance and durability

Antiviral activity of monoterpenes thymol, carvacrol and p-cymene against herpes simplex virus in vitro

Introduction: In recent years, with increased prevalence of viral infections and having no specific treatment  and also the continuous appearance of resistant viral strains, finding of novel antiviral agents is necessary.  Methods and Results: In this study, monoterpenes of thymol, carvacrol and p-cymene were screened for their inhibitory effect against herpes simplex virus type 1 (HSV-1) in vitro on Vero cell line CCL-81-ATCC using a plaque reduction assay. The antiviral activity of three monoterpenes (thymol, carvacrol and p-cymene) were evaluated by cytotoxicity assay, direct plaque test. In addition, the modes of antiviral action of these compounds were investigated during the viral infection cycle. Results showed that the inhibitory concentrations (IC50) were determined at 0.002%, 0.037% and >0.1%, for thymol, carvacrol, p-cymene, respectively. A manifestly dose-dependent virucidal activity against HSV-1 could be exhibited for compounds tested. In order to determine the mode of the inhibitory effect, compounds were added at different stages during the viral infection cycle. At maximum non-cytotoxic concentrations of the compounds, plaque formation was significantly reduced by more than 80% when HSV-1 was pre incubated with p-cymene. However, no inhibitory effect could be observed when the compounds were added to the cells prior to infection with HSV-1 or after the adsorption period. Conclusions: These results indicate that compounds affected HSV-1 mostly before adsorption and might interact with the viral envelope. Thymol exhibited a high selectivity index and seems to be a promising candidate for topical therapeutic application as antiviral agent for treatment of herpetic infections

Phytochemical compositions and biological activities of essential oil from Eremurus persicus (Joub. & Spach) Boiss.

Introduction: The genus Eremurus is native to Eastern Europe and temperate Asia. Particularly, Eremurus persicus (Joub. & Spach) Boiss. is highly valued in traditional foods and medicine. Scientific knowledge about E. persicus chemical composition and bioactivity is required.  Methods and Results: The present study is aimed to determine the volatile composition of E. persicus essential oil (EO) by means of gas chromatography coupled to flame ionization/mass spectrometry detector. Moreover, the antioxidant, antimicrobial, anticancer, and acetylcholinesterase inhibitory activities of the EO were tested. Interestingly, the anti-dermatophyte potency was close to that of the drug griseofulvin, with minimum fungicidal concentration ranging between 0.7 and 4.5% depending on the fungi strain. The EO was also effective against hepatocellular carcinoma (Hep-G2) and breast adenocarcinoma (MCF-7) human cancer cell lines in a concentration (200-1500 ng/mL)-dependent manner, with a decrease of the cell viability up to 65% and 52%, respectively. The E. persicus EO was rich in terpenes and oxygenated terpene derivatives. Individually, limonene (16.25%), geranylgeraniol (15.23%), n-nonanal (9.48%), geranyl acetone (9.12%), benzene acetaldehyde (8.51%), linalool (7.93%), α-pinene (6.89%), and 1,8-cineol (5.22%) were the most abundant volatile compounds and could be chosen as analytical markers of this essential oil. Conclusions: In conclusion, our results suggested that this EO possesses a wide range of bioactive properties that could be useful in nutraceutical, functional foods and cosmeceutical formulations

Anti-icing performance and durability of suspension plasma sprayed TiO2 coatings4

Superhydrophobic coatings are a potential solution for mitigating the in-flight icing problem for aircraft. However, to develop a superhydrophobic coating which can be practically used for aircraft and that possesses sufficient durability is an ongoing challenge. In this work, superhydrophobic coatings are developed using suspension plasma spraying (SPS) as a flexible, versatile and scalable coating technique. The anti-icing and deicing performances of these SPS coatings are studied in icing wind tunnel experiments. Furthermore, the durability of these SPS coatings is tested in dry particle and cloud-sized water droplet erosion and icing/deicing cyclic tests. The capability of SPS superhydrophobic coatings to reduce ice accretion is comparable to that of commercial superhydrophobic coatings but perform better in deicing tests using heating. Additionally, compared to commercial superhydrophobic coatings, the SPS coatings demonstrate significantly better performance in dry particle and icing/deicing cyclic tests while showing comparable durability in cloud-sized water droplet erosion tests. It is also shown that in case of high intensity water erosion, when the superhydrophobicity of SPS coatings deteriorates, it can be restored using a simple and quick retreatment process due to the robustness of the hierarchical micro-textured TiO2 base coatings

Engineering surface texture and hierarchical morphology of suspension plasma sprayed TiO 2 coatings to control wetting behavior and superhydrophobic properties

Beyond its conventional application for developing thermal barrier coatings, suspension plasma spraying (SPS) has shown promise for new applications focusing on surface textured coatings including superhydrophobic coatings. Such coatings have a dual-scale hierarchical morphology or so-called “cauliflower” features on the surface and they demonstrate extreme water repellence and mobility after treatment for lowering their surface energy. Studying and determining suitable process parameters to optimize the wetting properties of these coatings is the focus of this work. Herein, it is demonstrated that by carefully designing and controlling the process parameters, one can generate relatively fine and uniform dual-scale (hierarchical) surface textured coatings that after treatment for lowering their surface energy, show significantly improved water repellence and water mobility with water contact angles as high as 170° and sliding angles as low as 1.3°. It is also demonstrated that both scale levels of surface textures (i.e. micron-scale and nanoscale) are essential for having simultaneously improved water repellence and mobility. Furthermore, it is established that producing finer, more uniformly distributed and packed surface features lead to more consistent and desirable wetting properties. The results show the significant influence of pre-deposition surface roughness, precursor suspension rheology and plasma power on the structure and performance of the developed coatings

Chitosan-based nanoscale systems for doxorubicin delivery:Exploring biomedical application in cancer therapy

Abstract Green chemistry has been a growing multidisciplinary field in recent years showing great promise in biomedical applications, especially for cancer therapy. Chitosan (CS) is an abundant biopolymer derived from chitin and is present in insects and fungi. This polysaccharide has favorable characteristics, including biocompatibility, biodegradability, and ease of modification by enzymes and chemicals. CS‐based nanoparticles (CS‐NPs) have shown potential in the treatment of cancer and other diseases, affording targeted delivery and overcoming drug resistance. The current review emphasizes on the application of CS‐NPs for the delivery of a chemotherapeutic agent, doxorubicin (DOX), in cancer therapy as they promote internalization of DOX in cancer cells and prevent the activity of P‐glycoprotein (P‐gp) to reverse drug resistance. These nanoarchitectures can provide co‐delivery of DOX with antitumor agents such as curcumin and cisplatin to induce synergistic cancer therapy. Furthermore, co‐loading of DOX with siRNA, shRNA, and miRNA can suppress tumor progression and provide chemosensitivity. Various nanostructures, including lipid‐, carbon‐, polymeric‐ and metal‐based nanoparticles, are modifiable with CS for DOX delivery, while functionalization of CS‐NPs with ligands such as hyaluronic acid promotes selectivity toward tumor cells and prevents DOX resistance. The CS‐NPs demonstrate high encapsulation efficiency and due to protonation of amine groups of CS, pH‐sensitive release of DOX can occur. Furthermore, redox‐ and light‐responsive CS‐NPs have been prepared for DOX delivery in cancer treatment. Leveraging these characteristics and in view of the biocompatibility of CS‐NPs, we expect to soon see significant progress towards clinical translation

A review on Tradescantia : phytochemical constituents, biological activities and health-promoting effects

Tradescantia is a genus of herbaceous and perennial plants belonging to the Commelinaceae family and organized into three infrageneric classifications and 12 sections. More than 80 species within the genus have been used for centuries for medicinal purposes. Phytochemical compounds (from various species of the genus) such as coumarins, alkaloids, saponins, flavonoids, phenolics, tannins, steroids and terpenoids have recently been characterized and described with antioxidant, cytotoxic, anti-inflammatory, anticancer or antimicrobial properties. The objective of this review is to describe the different aspects of the genus Tradescantia, including its botanical characteristics, traditional uses, phytochemical composition, biological activities, and safety aspects.https://www.imrpress.com/journal/FBLdm2022Plant Production and Soil Scienc

The global, regional, and national burden of cirrhosis by cause in 195 countries and territories, 1990-2017 : a systematic analysis for the Global Burden of Disease Study 2017

Background Cirrhosis and other chronic liver diseases (collectively referred to as cirrhosis in this paper) are a major cause of morbidity and mortality globally, although the burden and underlying causes differ across locations and demographic groups. We report on results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 on the burden of cirrhosis and its trends since 1990, by cause, sex, and age, for 195 countries and territories. Methods We used data from vital registrations, vital registration samples, and verbal autopsies to estimate mortality. We modelled prevalence of total, compensated, and decompensated cirrhosis on the basis of hospital and claims data. Disability-adjusted life-years (DALYs) were calculated as the sum of years of life lost due to premature death and years lived with disability. Estimates are presented as numbers and age-standardised or age-specific rates per 100 000 population, with 95% uncertainty intervals (UIs). All estimates are presented for five causes of cirrhosis: hepatitis B, hepatitis C, alcohol-related liver disease, non-alcoholic steatohepatitis (NASH), and other causes. We compared mortality, prevalence, and DALY estimates with those expected according to the Socio-demographic Index (SDI) as a proxy for the development status of regions and countries. Findings In 2017, cirrhosis caused more than 1.32 million (95% UI 1.27-1.45) deaths (440000 [416 000-518 000; 33.3%] in females and 883 000 [838 000-967 000; 66.7%] in males) globally, compared with less than 899 000 (829 000-948 000) deaths in 1990. Deaths due to cirrhosis constituted 2.4% (2.3-2.6) of total deaths globally in 2017 compared with 1.9% (1.8-2.0) in 1990. Despite an increase in the number of deaths, the age-standardised death rate decreased from 21.0 (19.2-22.3) per 100 000 population in 1990 to 16.5 (15.8-18-1) per 100 000 population in 2017. Sub-Saharan Africa had the highest age-standardised death rate among GBD super-regions for all years of the study period (32.2 [25.8-38.6] deaths per 100 000 population in 2017), and the high-income super-region had the lowest (10.1 [9.8-10-5] deaths per 100 000 population in 2017). The age-standardised death rate decreased or remained constant from 1990 to 2017 in all GBD regions except eastern Europe and central Asia, where the age-standardised death rate increased, primarily due to increases in alcohol-related liver disease prevalence. At the national level, the age-standardised death rate of cirrhosis was lowest in Singapore in 2017 (3.7 [3.3-4.0] per 100 000 in 2017) and highest in Egypt in all years since 1990 (103.3 [64.4-133.4] per 100 000 in 2017). There were 10.6 million (10.3-10.9) prevalent cases of decompensated cirrhosis and 112 million (107-119) prevalent cases of compensated cirrhosis globally in 2017. There was a significant increase in age-standardised prevalence rate of decompensated cirrhosis between 1990 and 2017. Cirrhosis caused by NASH had a steady age-standardised death rate throughout the study period, whereas the other four causes showed declines in age-standardised death rate. The age-standardised prevalence of compensated and decompensated cirrhosis due to NASH increased more than for any other cause of cirrhosis (by 33.2% for compensated cirrhosis and 54.8% for decompensated cirrhosis) over the study period. From 1990 to 2017, the number of prevalent cases snore than doubled for compensated cirrhosis due to NASH and more than tripled for decompensated cirrhosis due to NASH. In 2017, age-standardised death and DALY rates were lower among countries and territories with higher SDI. Interpretation Cirrhosis imposes a substantial health burden on many countries and this burden has increased at the global level since 1990, partly due to population growth and ageing. Although the age-standardised death and DALY rates of cirrhosis decreased from 1990 to 2017, numbers of deaths and DALYs and the proportion of all global deaths due to cirrhosis increased. Despite the availability of effective interventions for the prevention and treatment of hepatitis B and C, they were still the main causes of cirrhosis burden worldwide, particularly in low-income countries. The impact of hepatitis B and C is expected to be attenuated and overtaken by that of NASH in the near future. Cost-effective interventions are required to continue the prevention and treatment of viral hepatitis, and to achieve early diagnosis and prevention of cirrhosis due to alcohol-related liver disease and NASH. Copyright (C) 2020 The Author(s). Published by Elsevier Ltd.Peer reviewe

Mapping 123 million neonatal, infant and child deaths between 2000 and 2017

Since 2000, many countries have achieved considerable success in improving child survival, but localized progress remains unclear. To inform efforts towards United Nations Sustainable Development Goal 3.2—to end preventable child deaths by 2030—we need consistently estimated data at the subnational level regarding child mortality rates and trends. Here we quantified, for the period 2000–2017, the subnational variation in mortality rates and number of deaths of neonates, infants and children under 5 years of age within 99 low- and middle-income countries using a geostatistical survival model. We estimated that 32% of children under 5 in these countries lived in districts that had attained rates of 25 or fewer child deaths per 1,000 live births by 2017, and that 58% of child deaths between 2000 and 2017 in these countries could have been averted in the absence of geographical inequality. This study enables the identification of high-mortality clusters, patterns of progress and geographical inequalities to inform appropriate investments and implementations that will help to improve the health of all populations