Journal articles on the topic 'Lubricant pathway'
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Xie, Mengxin, Bingli Pan, Ning Li, Shuang Zhao, Junjiang Yan, Shihao Guo, Zhe Chen, and Honggang Wang. "2D graphene/FeOCl heterojunctions with enhanced tribology performance as a lubricant additive for liquid paraffin." RSC Advances 12, no. 5 (2022): 2759–69. http://dx.doi.org/10.1039/d1ra06650a.
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Graphene/FeOCl (G/FeOCl) heterojunctions were prepared by microwave-pyrolysis, thoroughly characterised and used to probe the synergistic lubrication of G with FeOCl in liquid paraffin. We provide a pathway for low-friction lubricants by deploying G/FeOCl 2D materials.
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La, Duong Duc, Tuan Ngoc Truong, Thuan Q. Pham, Hoang Tung Vo, Nam The Tran, Tuan Anh Nguyen, Ashok Kumar Nadda, et al. "Scalable Fabrication of Modified Graphene Nanoplatelets as an Effective Additive for Engine Lubricant Oil." Nanomaterials 10, no. 5 (May 1, 2020): 877. http://dx.doi.org/10.3390/nano10050877.
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The use of nano-additives is widely recognized as a cheap and effective pathway to improve the performance of lubrication by minimizing the energy loss from friction and wear, especially in diesel engines. In this work, a simple and scalable protocol was proposed to fabricate a graphene additive to improve the engine lubricant oil. Graphene nanoplates (GNPs) were obtained by a one-step chemical exfoliation of natural graphite and were successfully modified with a surfactant and an organic compound to obtain a modified GNP additive, that can be facilely dispersed in lubricant oil. The GNPs and modified GNP additive were characterized using scanning electron microscopy, X-ray diffraction, atomic force microscopy, Raman spectroscopy, and Fourier-transform infrared spectroscopy. The prepared GNPs had wrinkled and crumpled structures with a diameter of 10–30 µm and a thickness of less than 15 nm. After modification, the GNP surfaces were uniformly covered with the organic compound. The addition of the modified GNP additive to the engine lubricant oil significantly enhanced the friction and antiwear performance. The highest reduction of 35% was determined for the wear scar diameter with a GNP additive concentration of approximately 0.05%. The mechanism for lubrication enhancement by graphene additives was also briefly discussed.
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Gulzar, M., H. H. Masjuki, M. A. Kalam, M. Varman, and I. M. Rizwanul Fattah. "Oil filter modification for biodiesel–fueled engine: A pathway to lubricant sustainability and exhaust emissions reduction." Energy Conversion and Management 91 (February 2015): 168–75. http://dx.doi.org/10.1016/j.enconman.2014.11.055.
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Liu, X., F. Zhou, Y. Liang, and W. Liu. "Benzotriazole as the additive for ionic liquid lubricant: one pathway towards actual application of ionic liquids." Tribology Letters 23, no. 3 (September 2, 2006): 191–96. http://dx.doi.org/10.1007/s11249-006-9050-7.
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Maglinao, Randy L., Eleazer P. Resurreccion, Sandeep Kumar, Amado L. Maglinao, Sergio Capareda, and Bryan R. Moser. "Hydrodeoxygenation–Alkylation Pathway for the Synthesis of a Sustainable Lubricant Improver from Plant Oils and Lignin-Derived Phenols." Industrial & Engineering Chemistry Research 58, no. 10 (January 22, 2019): 4317–30. http://dx.doi.org/10.1021/acs.iecr.8b05188.
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Ielchici, Christian Dejan, Stefan Krenn, and Stefan J. Eder. "A tribometer and methodology for wear and friction testing of porous journal bearings at elevated temperatures." Industrial Lubrication and Tribology 72, no. 8 (April 13, 2020): 1027–31. http://dx.doi.org/10.1108/ilt-08-2019-0351.
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Purpose This paper aims on a methodology to overcome the fact that conventional service life testing of porous journal bearings (PJBs) requires long test times and is not economical. Design/methodology/approach This paper sketches out a pathway to strongly accelerated life tests for PJBs enabled by high load and elevated temperature, which saves months or even years of testing. The testing time is not only reduced to a few weeks, but the results are also statistically secured via a multiple test rig construction of a custom-made tribometer. Findings An exemplary bearing-lubricant combination is tested in the mixed lubrication regime, where the coefficient of friction is monitored during the test. Originality/value A Weibull curve is fitted to the experimental results to show the survival probability of the combination over time. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2019-0351/
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Balakrishnan, Madhesan, Eric R. Sacia, Sanil Sreekumar, Gorkem Gunbas, Amit A. Gokhale, Corinne D. Scown, F. Dean Toste, and Alexis T. Bell. "Novel pathways for fuels and lubricants from biomass optimized using life-cycle greenhouse gas assessment." Proceedings of the National Academy of Sciences 112, no. 25 (June 8, 2015): 7645–49. http://dx.doi.org/10.1073/pnas.1508274112.
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Decarbonizing the transportation sector is critical to achieving global climate change mitigation. Although biofuels will play an important role in conventional gasoline and diesel applications, bioderived solutions are particularly important in jet fuels and lubricants, for which no other viable renewable alternatives exist. Producing compounds for jet fuel and lubricant base oil applications often requires upgrading fermentation products, such as alcohols and ketones, to reach the appropriate molecular-weight range. Ketones possess both electrophilic and nucleophilic functionality, which allows them to be used as building blocks similar to alkenes and aromatics in a petroleum refining complex. Here, we develop a method for selectively upgrading biomass-derived alkyl methyl ketones with >95% yields into trimer condensates, which can then be hydrodeoxygenated in near-quantitative yields to give a new class of cycloalkane compounds. The basic chemistry developed here can be tailored for aviation fuels as well as lubricants by changing the production strategy. We also demonstrate that a sugarcane biorefinery could use natural synergies between various routes to produce a mixture of lubricant base oils and jet fuels that achieve net life-cycle greenhouse gas savings of up to 80%.
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Jhon, Myung S., Pil Seung Chung, Robert L. Smith, and Lorenz T. Biegler. "A Description of Multiscale Modeling for the Head-Disk Interface Focusing on Bottom-Level Lubricant and Carbon Overcoat Models." Advances in Tribology 2013 (2013): 1–27. http://dx.doi.org/10.1155/2013/794151.
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The challenges in designing future head disk interface (HDI) demand efficient theoretical modeling tools with flexibility in investigating various combinations of perfluoropolyether (PFPE) and carbon overcoat (COC) materials. For broad range of time and length scales, we developed multiscale/multiphysical modeling approach, which can bring paradigm-shifting improvements in advanced HDI design. In this paper, we introduce our multiscale modeling methodology with an effective strategic framework for the HDI system. Our multiscale methodology in this paper adopts a bottom to top approach beginning with the high-resolution modeling, which describes the intramolecular/intermolecular PFPE-COC degrees of freedom governing the functional oligomeric molecular conformations on the carbon surfaces. By introducing methodology for integrating atomistic/molecular/mesoscale levels via coarse-graining procedures, we investigated static and dynamic properties of PFPE-COC combinations with various molecular architectures. By bridging the atomistic and molecular scales, we are able to systematically incorporate first-principle physics into molecular models, thereby demonstrating a pathway for designing materials based on molecular architecture. We also discussed future materials (e.g., graphene for COC, star-like PFPEs) and systems (e.g., heat-assisted magnetic recording (HAMR)) with higher scale modeling methodology, which enables the incorporation of molecular/mesoscale information into the continuum scale models.
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Hamdi, N. A., S. Sha’arani, N. F. Azman, S. B. Mohd Rafi, E. Norsin, and N. Othman. "Management of Waste Cooking Oil and its Potential for Value-added Materials: A Mini Review." IOP Conference Series: Earth and Environmental Science 1091, no. 1 (November 1, 2022): 012054. http://dx.doi.org/10.1088/1755-1315/1091/1/012054.
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Improper management of waste cooking oil in food industries like restaurants, hotels, and the use of retort technology in food processing is causing a devastating impact towards the environment. This is observed through odor problems and oil film formation on the surface of water bodies that increases the biological oxygen demand. Additionally, different types of cooking oil represent different physicochemical properties. This allows for the potential use of waste cooking oil as a carbon source for fungal growth thus contributing to the production of value-added products at a low cost and eco-friendly process. Biodegradation may take place by the enzymatic reaction which involves the hydrolysis of triglycerides and metabolized through the β-oxidation pathway to acetyl-CoA. Many fungal and bacterial strains capable of degrading vegetable cooking oils have been reported with most from the genus Aspergillus, Pseudomonas, Enterobacter, and others. From the industrial perspective, with the correct technology and proper recycling technique, waste cooking oil can be readily utilized as chemical building blocks in lubricant, candle, and fuel productions.
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Liu, Tongfang, Song Rui, and Sheng Li. "Layer-by-Layer Self-Assembly Composite Coatings for Improved Corrosion and Wear Resistance of Mg Alloy for Biomedical Applications." Coatings 11, no. 5 (April 27, 2021): 515. http://dx.doi.org/10.3390/coatings11050515.
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Mg alloys are promising biomedical metal due to their natural degradability, good processability, and favorable mechanical properties. However, the poor corrosion resistance limits their further clinical applications. In this study, the combined strategies of surface chemical treatment and layer-by-layer self-assembly were used to prepare composite coatings on Mg alloys to improve the biocorrosion resistance. Specially, alkalized AZ91 Mg alloy generated chemical linkage with silane via Si–O–Mg covalent bond at the interface. Subsequently, Si–OH group from silane formed a crosslinked silane layer by Si–O–Si network. Further chemical assembly with graphene oxide (GO), lengthened the diffusion pathway of corrosive medium. The chemically assembled composite coatings could firmly bond to Mg alloy substrate, which persistently and effectively acted as compact barriers against corrosion propagation. Improved biocorrosion resistance of AZ91 Mg alloy with self-assembly composite coatings of silane/GO was subsequently confirmed by immersion tests. Besides, the Mg alloy exhibited good wear resistance due to outside layer of GO with a lubricant effect. Cell viability of higher than 75% had also been found for the alloy with self-assembly composite coatings, which showed good cytocompatibility.
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Boratyński, Filip, Ewa Szczepańska, Davide De Simeis, Stefano Serra, and Elisabetta Brenna. "Bacterial Biotransformation of Oleic Acid: New Findings on the Formation of γ-Dodecalactone and 10-Ketostearic Acid in the Culture of Micrococcus luteus." Molecules 25, no. 13 (July 2, 2020): 3024. http://dx.doi.org/10.3390/molecules25133024.
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Microbial conversion of oleic acid (1) to form value-added industrial products has gained increasing scientific and economic interest. So far, the production of natural lactones with flavor and fragrance properties from fatty acids by non-genetically modified organisms (non-GMO) involves whole cells of bacteria catalyzing the hydration of unsaturated fatty acids as well as yeast strains responsible for further β-oxidation processes. Development of a non-GMO process, involving a sole strain possessing both enzymatic activities, significantly lowers the costs of the process and constitutes a better method from the customers’ point of view regarding biosafety issues. Twenty bacteria from the genus of Bacillus, Comamonas, Dietzia, Gordonia, Micrococcus, Pseudomonas, Rhodococcus and Streptomyces were screened for oxidative functionalization of oleic acid (1). Micrococcus luteus PCM525 was selected as the sole strain catalyzing the one-pot transformation of oleic acid (1) into natural valuable peach and strawberry-flavored γ-dodecalactone (6) used in the food, beverage, cosmetics and pharmaceutical industries. Based on the identified products formed during the process of biotransformation, we clearly established a pathway showing that oleic acid (1) is hydrated to 10-hydroxystearic acid (2), then oxidized to 10-ketostearic acid (3), giving 4-ketolauric acid (4) after three cycles of β-oxidation, which is subsequently reduced and cyclized to γ-dodecalactone (6) (Scheme 1). Moreover, three other strains (Rhodococcus erythropolis DSM44534, Rhodococcus ruber PCM2166, Dietzia sp. DSM44016), with high concomitant activities of oleate hydratase and alcohol dehydrogenase, were identified as efficient producers of 10-ketostearic acid (3), which can be used in lubricant and detergent formulations. Considering the prevalence of γ-dodecalactone (6) and 10-ketostearic acid (3) applications and the economic benefits of sustainable management, microbial bioconversion of oleic acid (1) is an undeniably attractive approach.
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Blaine, Steven, and Phillip E. Savage. "Reaction pathways in lubricant degradation. 2. n-Hexadecane autoxidation." Industrial & Engineering Chemistry Research 30, no. 9 (September 1991): 2185–91. http://dx.doi.org/10.1021/ie00057a020.
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Saha, Basudeb, and Dionisios G. Vlachos. "Synthesis of (hemi)cellulosic lubricant base oils via catalytic coupling and deoxygenation pathways." Green Chemistry 23, no. 14 (2021): 4916–30. http://dx.doi.org/10.1039/d1gc00429h.
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This review provides a critical review and perspective for bio-lubricant development from biomass due to the strong interest in creating a more diverse energy supply, environmental sustainability, and a carbon neutral bioeconomy.
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Blaine, Steven, and Phillip E. Savage. "Reaction pathways in lubricant degradation. 3. Reaction model for n-hexadecane autoxidation." Industrial & Engineering Chemistry Research 31, no. 1 (January 1992): 69–75. http://dx.doi.org/10.1021/ie00001a010.
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Natarajan, Sreekumar, Walter W. Olson, and Martin A. Abraham. "Reaction Pathways and Kinetics in the Degradation of Forging Lubricants." Industrial & Engineering Chemistry Research 39, no. 8 (August 2000): 2837–42. http://dx.doi.org/10.1021/ie9909237.
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Woll, Karsten, Tobias Neuhauser, Camilo Acuña, Donovan Diaz-Droguett, and Andreas Rosenkranz. "Rapid Thermal Characterization of Graphene Oxide—Nanocalorimetry as a Pathway for Novel Insights in Tribology." Lubricants 7, no. 11 (October 29, 2019): 96. http://dx.doi.org/10.3390/lubricants7110096.
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The use of solid lubricants such as graphene, graphene oxide, and other nanoparticles have gained notable attention in the tribological community to reduce friction and wear thus aiming at improved energy efficiency and sustainability. Tribological experiments unify rather extreme conditions such as high contact pressures, small contact areas, relative sliding motion, and rapid heating. This combination leads to mechanically- and/or thermally induced chemical, structural and microstructural modifications of the lubricating nanoparticles during rubbing thus altering their material’s properties. Due to the high sensitivity, we propose nanocalorimetry as the method of choice to shed more light on the thermally-induced processes and changes. As a model material for solid lubricants, we explore the transitions of graphene oxide under heating with 1000 °C/s up to 600 °C using quasi-adiabatic nanocalorimetry. We identify a strong exothermic runaway reaction at 317 °C. This runaway is preceded by exothermic reactions between 75–125 °C, which are correlated with the release of intercalated species and the formation of CO and CO2.
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Blaine, Steven, and Phillip E. Savage. "Reaction pathways in lubricant degradation. 1. Analytical characterization of n-hexadecane autoxidation products." Industrial & Engineering Chemistry Research 30, no. 4 (April 1991): 792–98. http://dx.doi.org/10.1021/ie00052a026.
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Lauterbach, Felix, and Volker Abetz. "An eco-friendly pathway to thermosensitive micellar nanoobjects via photoRAFT PISA: the full guide to poly(N-acryloylpyrrolidin)-block-polystyrene diblock copolymers." Soft Matter 16, no. 9 (2020): 2321–31. http://dx.doi.org/10.1039/c9sm02483b.
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Spherical macromolecular assemblies, so-called latexes, consisting of polystyrene (PS) resemble a relevant class of synthetic polymers used for a plethora of applications ranging from coatings or lubricants to biomedical applications.
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Hatta, T., K. N. Kishimoto, H. Okuno, and E. Itoi. "Lubricin expression is suppressed by hypoxia through HIF-1 mediated pathway." Osteoarthritis and Cartilage 20 (April 2012): S137—S138. http://dx.doi.org/10.1016/j.joca.2012.02.187.
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Nalesso, Giovanna, Bethan Lynne Thomas, Joanna Claire Sherwood, Jing Yu, Olga Addimanda, Suzanne Elizabeth Eldridge, Anne-Sophie Thorup, et al. "WNT16 antagonises excessive canonical WNT activation and protects cartilage in osteoarthritis." Annals of the Rheumatic Diseases 76, no. 1 (May 4, 2016): 218–26. http://dx.doi.org/10.1136/annrheumdis-2015-208577.
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ObjectiveBoth excessive and insufficient activation of WNT signalling results in cartilage breakdown and osteoarthritis. WNT16 is upregulated in the articular cartilage following injury and in osteoarthritis. Here, we investigate the function of WNT16 in osteoarthritis and the downstream molecular mechanisms.MethodsOsteoarthritis was induced by destabilisation of the medial meniscus in wild-type and WNT16-deficient mice. Molecular mechanisms and downstream effects were studied in vitro and in vivo in primary cartilage progenitor cells and primary chondrocytes. The pathway downstream of WNT16 was studied in primary chondrocytes and using the axis duplication assay in Xenopus.ResultsWNT16-deficient mice developed more severe osteoarthritis with reduced expression of lubricin and increased chondrocyte apoptosis. WNT16 supported the phenotype of cartilage superficial-zone progenitor cells and lubricin expression. Increased osteoarthritis in WNT16-deficient mice was associated with excessive activation of canonical WNT signalling. In vitro, high doses of WNT16 weakly activated canonical WNT signalling, but, in co-stimulation experiments, WNT16 reduced the capacity of WNT3a to activate the canonical WNT pathway. In vivo, WNT16 rescued the WNT8-induced primary axis duplication in Xenopus embryos.ConclusionsIn osteoarthritis, WNT16 maintains a balanced canonical WNT signalling and prevents detrimental excessive activation, thereby supporting the homeostasis of progenitor cells.
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Ruzic, Nenad, and Slobodan Petrovic. "Confirmation of the reaction pathway for obtaining 1-(stearamidoethyl)-2-hepta-decyl-2-i midazoline." Chemical Industry 56, no. 2 (2002): 43–49. http://dx.doi.org/10.2298/hemind0202043r.
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2-lmidazolines are components of many products, used in industry and households. 1-(Stearamidoethyl)-2-heptadecyl-2-imidazoline is a surface active compound, which after quaternization with dimethyl sulfate, is used in lubricants, detergents, shampoos, softeners and cosmetics products. Due to its importance, it was essential to establish the exact reaction pathway for obtaining this compound. Diethylene triamine and stearic acid were used as the starting components. Using titrimetric analysis, and IR and 1H NMR spectros-copic analysis, as well as UV-Vis spectrophotometry it was established that the main intermediate was the 1,3-diamide bis(stearamidoethyl)amine. Earlier investigations conducted by some authors, using exclusively titrimetric analysis, showed that the main intermediate was the 1,2-diamide. In this paper it was proved that the assumption of these authors that salicylaldehiyde would react only with the primary and not the secondary amine groups was wrong. 1,2-Diamide is the main product of the hydrolysis of 1-(stearamido-ethyl)-2-heptadecyl-2-imidazoline. It was shown, in this paper that the reaction of diethylene triamine with stearic acid in xylene at the reflux temperature, yields the salt of 1-(stearamidoethyl)-2-heptadecyl-2-imidazoline and stearic acid.
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van Heusden, Catharina, Barbara R. Grubb, Brian Button, and Eduardo R. Lazarowski. "Airway Epithelial Nucleotide Release Contributes to Mucociliary Clearance." Life 11, no. 5 (May 11, 2021): 430. http://dx.doi.org/10.3390/life11050430.
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Mucociliary clearance (MCC) is a dominant component of pulmonary host defense. In health, the periciliary layer (PCL) is optimally hydrated, thus acting as an efficient lubricant layer over which the mucus layer moves by ciliary force. Airway surface dehydration and production of hyperconcentrated mucus is a common feature of chronic obstructive lung diseases such as cystic fibrosis (CF) and chronic bronchitis (CB). Mucus hydration is driven by electrolyte transport activities, which in turn are regulated by airway epithelial purinergic receptors. The activity of these receptors is controlled by the extracellular concentrations of ATP and its metabolite adenosine. Vesicular and conducted pathways contribute to ATP release from airway epithelial cells. In this study, we review the evidence leading to the identification of major components of these pathways: (a) the vesicular nucleotide transporter VNUT (the product of the SLC17A9 gene), the ATP transporter mediating ATP storage in (and release from) mucin granules and secretory vesicles; and (b) the ATP conduit pannexin 1 expressed in non-mucous airway epithelial cells. We further illustrate that ablation of pannexin 1 reduces, at least in part, airway surface liquid (ASL) volume production, ciliary beating, and MCC rates.
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Sturtevant, Drew, Shaoping Lu, Zhi-Wei Zhou, Yin Shen, Shuo Wang, Jia-Ming Song, Jinshun Zhong, et al. "The genome of jojoba (Simmondsia chinensis): A taxonomically isolated species that directs wax ester accumulation in its seeds." Science Advances 6, no. 11 (March 2020): eaay3240. http://dx.doi.org/10.1126/sciadv.aay3240.
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Seeds of the desert shrub, jojoba (Simmondsia chinensis), are an abundant, renewable source of liquid wax esters, which are valued additives in cosmetic products and industrial lubricants. Jojoba is relegated to its own taxonomic family, and there is little genetic information available to elucidate its phylogeny. Here, we report the high-quality, 887-Mb genome of jojoba assembled into 26 chromosomes with 23,490 protein-coding genes. The jojoba genome has only the whole-genome triplication (γ) shared among eudicots and no recent duplications. These genomic resources coupled with extensive transcriptome, proteome, and lipidome data helped to define heterogeneous pathways and machinery for lipid synthesis and storage, provided missing evolutionary history information for this taxonomically segregated dioecious plant species, and will support efforts to improve the agronomic properties of jojoba.
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Murru, Clarissa, Rosana Badía-Laíño, and Marta Elena Díaz-García. "Synthesis and Characterization of Green Carbon Dots for Scavenging Radical Oxygen Species in Aqueous and Oil Samples." Antioxidants 9, no. 11 (November 19, 2020): 1147. http://dx.doi.org/10.3390/antiox9111147.
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Carbon dots (CDs) due to their unique optical features, chemical stability and low environmental hazard are applied in different fields such as metal ion sensing, photo-catalysis, bio-imaging and tribology, among others. The aims of the present research were to obtain CDs from vegetable wastes (tea and grapes) as carbon sources and to explore their potential properties as radical scavengers. CDs from glutathione/citric acid (GCDs) were synthetized for comparison purposes. The CDs were investigated for their chemical structure, morphology, optical and electronical properties. The antioxidant activity has been explored by DPPH and Folin-Ciocelteau assays in aqueous media. Due to their solubility in oil, the CDs prepared from tea wastes and GCDs were assayed as antioxidants in a mineral oil lubricant by potentiometric determination of the peroxide value. CDs from tea wastes and GCDs exhibited good antioxidant properties both in aqueous and oil media. Possible mechanisms, such as C-addition to double bonds, H-abstraction and SOMO-CDs conduction band interaction, were proposed for the CDs radical scavenging activity. CDs from natural sources open new application pathways as antioxidant green additives.
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Cheng, Zhu, Carolyn R. Shurer, Samuel Schmidt, Vivek K. Gupta, Grace Chuang, Jin Su, Amanda R. Watkins, et al. "The surface stress of biomedical silicones is a stimulant of cellular response." Science Advances 6, no. 15 (April 2020): eaay0076. http://dx.doi.org/10.1126/sciadv.aay0076.
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Silicones are commonly used for lubrication of syringes, encapsulation of medical devices, and fabrication of surgical implants. While silicones are generally viewed as relatively inert to the cellular milieu, they can mediate a variety of inflammatory responses and other deleterious effects, but the mechanisms underlying the bioactivity of silicones remain unresolved. Here, we report that silicone liquids and gels have high surface stresses that can strongly resist deformation at cellular length scales. Biomedical silicones, including syringe lubricants and fillings from FDA-approved breast implants, readily adsorb matrix proteins and activate canonical rigidity sensing pathways through their surface stresses. In 3D culture models, liquid silicone droplets support robust cellular adhesion and the formation of multinucleated monocyte-derived cell masses that recapitulate phenotypic aspects of granuloma formation in the foreign body response. Together, our findings implicate surface stress as a cellular stimulant that should be considered in application of silicones for biomedical purposes.
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Taylor, R. W., Christine Smith, and M. White. "In Vitro Investigation of the Synthetic Sebum Adsorbing Efficacy of Acrylate Copolymer as an Excipient And In Clinac ™ Oc." Microscopy and Microanalysis 5, S2 (August 1999): 1180–81. http://dx.doi.org/10.1017/s143192760001922x.
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While sebum provides several functions in the integument, there is considerable interest in the control of excess sebum on the human skin. The primary function of sebum is to lubricate and waterproof the stratum cornenum layer, in addition to preventing hair from becoming brittle. In several cases, the secretion of sebum is inhibited as a result of blockage of the drainage pathway for the sebaceous glands which may result in abnormal skin conduction (1,2). Clinac™ OC (Oil Control) has been developed with a special oil adsorbing polymer, DVB/lsobornyl Methacrylate/Lautyl Methacrylate Copolymer (3). This particular copolymer posses the capacity to adsorb oils because of its high affinity for hydrophobic nonpolar substances. The purpose of this investigation is to show the adsorptive capacity of the acrylate copolymer in Clinac™ OC preparation and in buffer.The acrylate polymer was incubated in artificial sebum for 4 hrs and 8 hrs at 37 C.
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Joo, Sung-Yeon, Hee-Wang Yoo, Sharad Sarak, Byung-Gee Kim, and Hyungdon Yun. "Enzymatic Synthesis of ω-Hydroxydodecanoic Acid By Employing a Cytochrome P450 from Limnobacter sp. 105 MED." Catalysts 9, no. 1 (January 8, 2019): 54. http://dx.doi.org/10.3390/catal9010054.
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ω-Hydroxylated fatty acids are valuable and versatile building blocks for the production of various adhesives, lubricants, cosmetic intermediates, etc. The biosynthesis of ω-hydroxydodecanoic acid from vegetable oils is one of the important green pathways for their chemical-based synthesis. In the present study, the novel monooxygenase CYP153AL.m from Limnobacter sp. 105 MED was used for the whole-cell biotransformations. We constructed three-component system that was comprised of CYP153AL.m, putidaredoxin and putidaredoxin reductase from Pseudomonas putida. This in vivo study demonstrated that CYP153AL.m is a powerful catalyst for the biosynthesis of ω-hydroxydodecanoic acid. Under optimized conditions, the application of a solid-state powdered substrate rather than a substrate dissolved in DMSO significantly enhanced the overall reaction titer of the process. By employing this efficient system, 2 g/L of 12-hydroxydodecanoic acid (12-OHDDA) was produced from 4 g/L of its corresponding fatty acid, which was namely dodecanoic acid. Furthermore, the system was extended to produce 3.28 g/L of 12-OHDDA using 4 g/L of substrate by introducing native redox partners. These results demonstrate the utility of CYP153AL.m-catalyzed biotransformations in the industrial production of 12-OHDDA and other valuable building blocks.
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Soorajkumar, Anjana, Ebrahim Alakraf, Mohammed Uddin, Stefan S. Du Plessis, Alawi Alsheikh-Ali, and Richard K. Kandasamy. "Computational Analysis of Short Linear Motifs in the Spike Protein of SARS-CoV-2 Variants Provides Possible Clues into the Immune Hijack and Evasion Mechanisms of Omicron Variant." International Journal of Molecular Sciences 23, no. 15 (August 8, 2022): 8822. http://dx.doi.org/10.3390/ijms23158822.
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Short linear motifs (SLiMs) are short linear sequences that can mediate protein–protein interaction. Mimicking eukaryotic SLiMs to compete with extra- or intracellular binding partners, or to sequester host proteins is the crucial strategy of viruses to pervert the host system. Evolved proteins in viruses facilitate minimal protein–protein interactions that significantly affect intracellular signaling networks. Unfortunately, very little information about SARS-CoV-2 SLiMs is known, especially across SARS-CoV-2 variants. Through the ELM database-based sequence analysis of spike proteins from all the major SARS-CoV-2 variants, we identified four overriding SLiMs in the SARS-CoV-2 Omicron variant, namely, LIG_TRFH_1, LIG_REV1ctd_RIR_1, LIG_CaM_NSCaTE_8, and MOD_LATS_1. These SLiMs are highly likely to interfere with various immune functions, interact with host intracellular proteins, regulate cellular pathways, and lubricate viral infection and transmission. These cellular interactions possibly serve as potential therapeutic targets for these variants, and this approach can be further exploited to combat emerging SARS-CoV-2 variants.
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Xue, Jiapeng, Jinnan Chen, Quan Shen, Deva Chan, Jun Li, Adam P. Tanguay, Tannin A. Schmidt, Faizan Niazi, and Anna Plaas. "Addition of High Molecular Weight Hyaluronic Acid to Fibroblast-Like Stromal Cells Modulates Endogenous Hyaluronic Acid Metabolism and Enhances Proteolytic Processing and Secretion of Versican." Cells 9, no. 7 (July 13, 2020): 1681. http://dx.doi.org/10.3390/cells9071681.
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We have examined the effect of exogenous linear chain high molecular weight hyaluronic acid (HMW HA) on endogenously synthesized hyaluronic acid (HA) and associated binding proteins in primary cultures of fibroblast-like stromal cells that were obtained by collagenase digestion of the murine peripatellar fat pad. The cultures were expanded in DMEM that was supplemented with fetal bovine serum and basic fibroblast growth factor (bFGF) then exposed to macrophage-colony-stimulating factor (MCSF) to induce macrophage properties, before activation of inflammatory pathways using E. coli lipopolysaccharide (LPS). Under all culture conditions, a significant amount of endogenously synthesized HA localized in LAMP1-positive lysosomal vesicles. However, this intracellular pool was depleted after the addition of exogenous HMW HA and was accompanied by enhanced proteolytic processing and secretion of de novo synthesized versican, much of which was associated with endosomal compartments. No changes were detected in synthesis, secretion, or proteolytic processing of aggrecan or lubricin (PRG4). The addition of HMW HA also modulated a range of LPS-affected genes in the TLR signaling and phagocytosis pathways, as well as endogenous HA metabolism genes, such as Has1, Hyal1, Hyal2, and Tmem2. However, there was no evidence for association of endogenous or exogenous HMW HA with cell surface CD44, TLR2 or TLR4 protein, suggesting that its physiochemical effects on pericelluar pH and/or ionic strength might be the primary modulators of signal transduction and vesicular trafficking by this cell type. We discuss the implications of these findings in terms of a potential in vivo effect of therapeutically applied HMW HA on the modification of osteoarthritis-related joint pathologies, such as pro-inflammatory and degradative responses of multipotent mesenchymal cells residing in the synovial membrane, the underlying adipose tissue, and the articular cartilage surface.
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Mashayekhi, V., K. Haj Mohammad Ebrahim Tehrani, M. Hashemzaei, K. Tabrizian, J. Shahraki, and M.-J. Hosseini. "Mechanistic approach for the toxic effects of perfluorooctanoic acid on isolated rat liver and brain mitochondria." Human & Experimental Toxicology 34, no. 10 (January 13, 2015): 985–96. http://dx.doi.org/10.1177/0960327114565492.
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Background: Perfluorooctanoic acid (PFOA) is one of the most widely used perfluoroalkanes as surfactants, lubricants and processing aids in the production of polymers, which has also been detected in the environment, wildlife and human body. Animal studies indicated that PFOA caused a wide array of toxic effects including liver and brain dysfunction, carcinogenicity and reproductive and developmental toxicity. Based on the established role of mitochondria-mediated pathways in the observed toxic effects of many drugs and chemicals, in this study, the potential toxic effects of PFOA on mitochondria isolated from rat liver and brain have been investigated. Method: Mitochondria were isolated by differential centrifugation method and incubated with different concentrations of PFOA (0.5–1.5 mM). The effects of PFOA were assessed on a series of mitochondrial parameters including reactive oxygen species (ROS) formation, activities of mitochondrial complexes I/II/III, reduced glutathione (GSH) content, adenosine triphosphate (ATP) level, membrane potential, lipid peroxidation (LPO), mitochondrial swelling and cytochrome c release. Results: The data on liver mitochondria indicated that PFOA-induced ROS elevation in both mitochondrial complexes I and III, mitochondrial membrane potential collapse, swelling, cytochrome c release and decreased ATP level which induces apoptosis or necrosis. On brain mitochondria, PFOA showed fairly similar effects on the above-mentioned parameters. However, different results were obtained when the effect of PFOA was assessed on LPO and complex II activity. Conclusions: Due to the fact that PFOA had toxic effects on the mitochondria isolated, it could be suggested that mitochondrial toxicity could be a plausible mechanism for the toxic effects of this fluorochemical on liver and brain function.
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Vojinovic-Miloradov, Mirjana, Maja Turk-Sekulic, Jelena Radonic, Natasa Milic, Nevena Grujic-Letic, Ivana Mihajlovic, and Maja Milanovic. "Industrial emerging chemicals in the environment." Chemical Industry 68, no. 1 (2014): 51–62. http://dx.doi.org/10.2298/hemind121110028v.
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In the recent time, considerable interest has grown concerning the presence of the emerging industrial chemicals, EmIC. They are contaminants that have possible pathway to enter to the environment and they are dominantly released by industrial and anthropogenic activities. EmIC are applied in different fields using as industrial chemicals (new and recently recognized), global organic contaminants (flame retardant chemicals), pharmaceuticals (for both human and animal uses), endocrine-modulating compounds, biological metabolites, personal care products, household chemicals, nanomaterial (energy storage products, lubricants), anticorrosive and agriculture chemicals and others that are applied to a wide variety of everyday items such as clothing, upholstery, electronics and automobile interiors. NORMAN (Network of reference laboratories for monitoring of emerging environmental pollutants) has established an open, dynamic, list of emerging substances and pollutants. EmIC have been recently detected in the environment due to their long-term presence, pseudo-persistence and increased use. Improvements in sophisticated analytical methods and time integrative passive sampling have enabled the identification and quantification of EmIC, in very low concentrations (ppb, ppt and lower), which likely have been present in all environmental mediums for decades. Passive technology is an innovative technique for the time-integrated measurement of emerging contaminants in water, sediment, soil and air. Passive samplers are simple handling cost-effective tool that could be used in environmental monitoring programmes. These devices are now being considered as a part of an emerging strategy for monitoring a range of emerging industrial chemicals and priority pollutants in the aquatic environment. EmIC are substances that are not included in the routine monitoring programmes and whose fate, behaviour and (eco)toxicological effects are still not well understood. Emerging pollutants have no regulatory standards based on peer-reviewed science. EmIC might jeopardize aquatic environment. The first screening analyses of emerging industrial and priority organic contaminants in the Danube surface water, in the vicinity of Novi Sad, have been done and approximately more than 140 compounds have been registered. The new sampling campaign, screening and target analyses are in progress.
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Kumar, Bhupander, Sanjay Kumar, and Chandra Shekhar Sharma. "Congener specific distribution and health risk assessment of polychlorinated biphenyls in urban soils." Journal of Xenobiotics 2, no. 1 (November 13, 2012): 10. http://dx.doi.org/10.4081/xeno.2012.e10.
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Polychlorinated biphenyls (PCBs) were primarily used in transformers and capacitors, lubricants, flame retardants, plasticizers, paint, carbonless papers, etc. These are capable of long-range atmospheric transport and have been designated as persistent organic pollutants by the Stockholm Convention. Due to their characteristic properties, PCBs are found worldwide in all environmental matrices (including human) and biota. Soils are usually considered to be the source as well as sink for environmental pollutants, with cumulative effects of long-range atmospheric transport and local sources. Around the world, comparatively higher concentrations of PCBs have been reported in urban soils than suburban or rural soils. Higher amount of PCBs in urban soils may cause toxicological health risks to urban residents through ingestion, inhalation and skin contact. This paper presents the PCB distribution in soils from Delhi, India, and exposure risk estimates for human health through soil ingestion. The concentration of ΣPCBs ranged between 1.08-100.67 ng g<sup>–1</sup> (mean 21.16 ng g<sup>–1</sup>±5.24 ng g<sup>–1</sup>), which was much lower than the Canadian soil quality guideline value of 1.3 mg/kg or 1300 ng g<sup>–1</sup>. Human health risk estimates through the soil ingestion pathway were made in terms of lifetime average daily dose (LADD), incremental lifetime cancer risks and non-carcinogenic hazard quotient (HQ). The LADD for Delhi adults and children was 3.02x10<sup>–8</sup> mg kg<sup>–1</sup> d<sup>–1</sup> and 1.57x10<sup>–7</sup> mg kg<sup>–1</sup> d<sup>–1</sup>, respectively, which corresponds to toxic equivalent quotients (TEQ) intake of 0.105 pg TEQ kg<sup>–1</sup> d<sup>–1</sup> (0.735 pg TEQ kg<sup>–1</sup> week<sup>–1</sup>) and 0.543 pg TEQ kg<sup>–1</sup> d<sup>–1</sup> (3.801 pg TEQ kg<sup>–1</sup> week<sup>–1</sup>), respectively. The estimated LADD for Delhi residents was lower than the acceptable intake values recommended by the World Health Organization (1 pg TEQ kg<sup>–1</sup> d<sup>–1</sup>), the European Commission (14 pg TEQ kg<sup>–1</sup>;1 week<sup>–1</sup>) and by the Japanese government (4 pg TEQ kg<sup>–1</sup> d<sup>–1</sup>). The probability of cancer risk ranges from 6.04x10<sup>–8</sup> (ΣPCBs) to 1.57x10<sup>–5</sup> (ΣTEQ) and 3.13x10–7 (ΣPCBs) to 8.15x10–5 (ΣTEQ) for adults and children, respectively, and was within acceptable ranges of 10<sup>–6</sup> to 10<sup>–4</sup>. The non-carcinogenic risk in terms of health HQ was 0.105 and 0.330 for adults and children, respectively, which was lower than the acceptable limit of 1. The study found lower concentrations of PCBs than guideline values and low health risk estimates through the soil ingestion pathway within acceptable levels, indicating a minimum risk for Delhi residents.
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Blitzblau, Hannah G., Andrew L. Consiglio, Paulo Teixeira, Donald V. Crabtree, Shuyan Chen, Oliver Konzock, Gamuchirai Chifamba, et al. "Production of 10-methyl branched fatty acids in yeast." Biotechnology for Biofuels 14, no. 1 (January 7, 2021). http://dx.doi.org/10.1186/s13068-020-01863-0.
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Abstract Background Despite the environmental value of biobased lubricants, they account for less than 2% of global lubricant use due to poor thermo-oxidative stability arising from the presence of unsaturated double bonds. Methyl branched fatty acids (BFAs), particularly those with branching near the acyl-chain mid-point, are a high-performance alternative to existing vegetable oils because of their low melting temperature and full saturation. Results We cloned and characterized two pathways to produce 10-methyl BFAs isolated from actinomycetes and γ-proteobacteria. In the two-step bfa pathway of actinomycetes, BfaB methylates Δ9 unsaturated fatty acids to form 10-methylene BFAs, and subsequently, BfaA reduces the double bond to produce a fully saturated 10-methyl branched fatty acid. A BfaA-B fusion enzyme increased the conversion efficiency of 10-methyl BFAs. The ten-methyl palmitate production (tmp) pathway of γ-proteobacteria produces a 10-methylene intermediate, but the TmpA putative reductase was not active in E. coli or yeast. Comparison of BfaB and TmpB activities revealed a range of substrate specificities from C14-C20 fatty acids unsaturated at the Δ9, Δ10 or Δ11 position. We demonstrated efficient production of 10-methylene and 10-methyl BFAs in S. cerevisiae by secretion of free fatty acids and in Y. lipolytica as triacylglycerides, which accumulated to levels more than 35% of total cellular fatty acids. Conclusions We report here the characterization of a set of enzymes that can produce position-specific methylene and methyl branched fatty acids. Yeast expression of bfa enzymes can provide a platform for the large-scale production of branched fatty acids suitable for industrial and consumer applications.
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Domínguez-García, S., L. Béjar-Gómez, R. Huirache-Acuna, J. Lara-Romero, and R. Maya-Yescas. "Delumping Strategy to Infer Lubrication Reaction Pathways in Internal Combustion Engines." International Journal of Chemical Reactor Engineering 18, no. 1 (December 5, 2019). http://dx.doi.org/10.1515/ijcre-2019-0043.
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Abstract Lubricant reactions in internal combustion engines follow complex reaction pathways, in which oil (hydrocarbons) and additives form protecting films (known as tribofilms) on the surfaces of the cylinder-piston couple. Up-to-date there is not a fundamental model useful to describe the chemistry involved in formation of these tribofilms, and degradation of oils and additives as result of working time of the engine. One of the main problems associated is the impossible measuring of the actual phenomena inside the engine, at working conditions. In order to model formation of tribofilms, starting by lumping two main groups of lubricating molecules, anti-shear and anti-wear, the lumped kinetics model for degradation products was solved, based on actual data collected in commercial engine workshops. Later these two-lump reaction schemes were delumped into two new systems, each one consisting of three lumps, in order to infer lubricant reaction pathways that form tribofilms and degrade lubricants. Distribution of anti-shear and anti-wear lubricants in tribofilms was predicted by simulation of these two delumped schemes.
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Zhang, Yang, Xiao Guo, Huaiyi Yang, and Shuobo Shi. "The Studies in Constructing Yeast Cell Factories for the Production of Fatty Acid Alkyl Esters." Frontiers in Bioengineering and Biotechnology 9 (January 11, 2022). http://dx.doi.org/10.3389/fbioe.2021.799032.
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Fatty acid alkyl esters have broad applications in biofuels, lubricant formulas, paints, coatings, and cosmetics. Traditionally, these esters are mostly produced through unsustainable and energy-intensive processes. In contrast, microbial production of esters from renewable and sustainable feedstocks may provide a promising alternative and has attracted widespread attention in recent years. At present, yeasts are used as ideal hosts for producing such esters, due to their availability for high-density fermentation, resistance to phage infection, and tolerance against toxic inhibitors. Here, we summarize recent development on the biosynthesis of alkyl esters, including fatty acid ethyl esters (FAEEs), fatty acid short-branched chain alkyl esters (FASBEs), and wax esters (WEs) by various yeast cell factories. We focus mainly on the enzyme engineering strategies of critical wax ester synthases, and the pathway engineering strategies employed for the biosynthesis of various ester products. The bottlenecks that limit productivity and their potential solutions are also discussed in this review.
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Du, Yuefeng, Zhenyu Zhang, Dong Wang, Lezhen Zhang, Junfeng Cui, Yapeng Chen, Mingliang Wu, et al. "Enhanced tribological properties of aligned graphene-epoxy composites." Friction, April 28, 2021. http://dx.doi.org/10.1007/s40544-021-0496-2.
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AbstractThe random distribution of graphene in epoxy matrix hinders the further applications of graphene-epoxy composites in the field of tribology. Hence, in order to fully utilize the anisotropic properties of graphene, highly aligned graphene-epoxy composites (AGEC) with horizontally oriented structure have been fabricated via an improved vacuum filtration freeze-drying method. The frictional tests results indicated that the wear rate of AGEC slowly increased from 5.19×10−6 mm3/(N·m) to 2.87×10−5 mm3/(N·m) with the increasing of the normal load from 2 to 10 N, whereas the friction coefficient (COF) remained a constant of 0.109. Compared to the neat epoxy and random graphene-epoxy composites (RGEC), the COF of AGEC was reduced by 87.5% and 71.2%, and the reduction of wear rate was 86.6% and 85.4% at most, respectively. Scanning electron microscope (SEM) observations illustrated that a compact graphene self-lubricant film was formed on the worn surface of AGEC, which enables AGEC to possess excellent tribological performance. Finally, in light of the excellent tribological properties of AGEC, this study highlights a pathway to expand the tribological applications of graphene-epoxy composites.
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Baeriswyl, Thomas, Martina Schaettin, Simone Leoni, Alexandre Dumoulin, and Esther T. Stoeckli. "Endoglycan Regulates Purkinje Cell Migration by Balancing Cell-Cell Adhesion." Frontiers in Neuroscience 16 (June 20, 2022). http://dx.doi.org/10.3389/fnins.2022.894962.
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The importance of cell adhesion molecules for the development of the nervous system has been recognized many decades ago. Functional in vitro and in vivo studies demonstrated a role of cell adhesion molecules in cell migration, axon growth and guidance, as well as synaptogenesis. Clearly, cell adhesion molecules have to be more than static glue making cells stick together. During axon guidance, cell adhesion molecules have been shown to act as pathway selectors but also as a means to prevent axons going astray by bundling or fasciculating axons. We identified Endoglycan as a negative regulator of cell-cell adhesion during commissural axon guidance across the midline. The presence of Endoglycan allowed commissural growth cones to smoothly navigate the floor-plate area. In the absence of Endoglycan, axons failed to exit the floor plate and turn rostrally. These observations are in line with the idea of Endoglycan acting as a lubricant, as its presence was important, but it did not matter whether Endoglycan was provided by the growth cone or the floor-plate cells. Here, we expand on these observations by demonstrating a role of Endoglycan during cell migration. In the developing cerebellum, Endoglycan was expressed by Purkinje cells during their migration from the ventricular zone to the periphery. In the absence of Endoglycan, Purkinje cells failed to migrate and, as a consequence, cerebellar morphology was strongly affected. Cerebellar folds failed to form and grow, consistent with earlier observations on a role of Purkinje cells as Shh deliverers to trigger granule cell proliferation.
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DenAdel, Michelle A., Sarah E. Hendrickson, and Esther Fuchs. "Stevens Johnson Syndrome: Past, Present, and Future Directions Gynecologic Manifestations and Management in SJS/TEN." Frontiers in Medicine 9 (July 4, 2022). http://dx.doi.org/10.3389/fmed.2022.874445.
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Stevens Johnson Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) are severe mucocutaneous hypersensitivity disorders characterized by sudden onset epidermal necrosis. Acute manifestations of SJS/TEN often include vulvovaginal erosions, ulcerations, vaginal discharge, bleeding, vaginal pain, dysuria, and urinary retention. If not treated, this can lead to complications such as vulvovaginal adhesions, vaginal stenosis or dryness, pain, dyspareunia, bleeding, and adenosis. Even with adequate treatment, there are lasting impacts including difficulty with vaginal exams and psychological distress. Early recognition and treatment of vulvovaginal involvement are crucial to preventing severe sequelae. Despite the potentially devastating consequences of genitourinary involvement of SJS/TEN, involvement of the mucocutaneous surfaces of the vulva and vagina is inconsistently documented, and protocols for treatment and follow-up are not well-established. The treatment of vulvovaginal involvement relies largely on expert opinion, and there is little data on the efficacy of suggested management. The goal of this review was to identify whether establishing a clinical pathway increased treatment of vulvovaginal SJS/TEN and to optimize our standardized protocol to prevent genitourinary sequelae.MethodsWe conducted a retrospective chart review of female patients with SJS/TEN at Harborview Medical Center, University of Washington from 2008 to 2021. Demographic and clinical data including gynecologic consultation, exam findings, treatment regimens, and outpatient follow-up were collected from the electronic medical record. We compared data before and after implementation of a clinical care pathway in 2017.ResultsWe reviewed a total of 88 charts of women with possible SJS/TEN between 2008 and 2021. Of these 88 charts, 77 were found to have clear biopsy proven diagnosis of SJS/TEN. A total of 42 patients were found to have vulvovaginal involvement (55%) and gynecology was consulted in 43% of cases. 50% of patients (n = 21) with vulvovaginal involvement were recommended treatment with vaginal dilators and steroid ointment and 34% of patients with genital involvement received no treatment.Between 2008 and May of 2017 (pre-protocol), we found 55 patients with SJS/TEN. 55% of patients (n = 29) had vulvovaginal involvement (n = 26 vulvar, n = 21 vaginal). Gynecology was only consulted in 26% (n = 14) of patients. Of the 21 females with vaginal involvement, only 38% (n = 8) had dilators/vaginal molds with steroid ointment recommended. Of the 26 females with vulvar involvement, 31% (n = 8) had no vulvar treatment recommendations with the remaining 69% having some documentation that ranged from gauze placement only (19%) to topical lidocaine, barrier cream, antibiotic or antifungal cream/ ointment, lubricant, or topical steroid ointment (50%). Menstrual suppression was recommended in 38% (n = 9) of menstruating females. An antifungal medication was only prescribed in 4% of patients.Following implementation of the clinical pathway for the treatment of SJS/TEN in 2017, 22 females with SJS/TEN were identified. 72% (n = 16) had documented vulvovaginal involvement (n = 16 vulvar, n = 9 vaginal). Gynecology consultations took place in 86% (n = 19) of patients. We identified several improvements after implementation of the protocol. Gynecology consults overall increased from 26% pre-, to 86% post-protocol. For patients with vulvovaginal involvement, consultations were completed in 93% compared to 50% prior to protocol. Of note, the finding of vulvovaginal lesions increased from 53 to 72%. Dilator use with topical steroid ointment was consistently recommended, as was antifungal use and menstrual suppression.ConclusionHaving a protocol in place for treatment of female patients with SJS/TEN increased the consistency of Gynecologic consultation and the documentation and treatment of vulvovaginal SJS/TEN. We identified the need to improve clinical follow-up after discharge from the hospital, which could be arranged as multidisciplinary visits and would be a good option to assess long-term outcomes (pain, sexual activity, etc.). With regards to future directions, we are in the process of assessing long-term data on quality of life and sexual functioning. The impact of treatment in the acute setting on the development of chronic sequelae needs to be established, as does the management of long-term sequelae like vaginal dryness, pain, dyspareunia. The role of local estrogen and vaginal laser still needs to be explored. Pelvic floor physical therapy might play a significant role in rehabilitation and has yet to be studied.
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Lubbers, Ronnie J. M., Adiphol Dilokpimol, Jaap Visser, Kristiina S. Hildén, Miia R. Mäkelä, and Ronald P. de Vries. "Discovery and functional analysis of a salicylic acid hydroxylase from Aspergillus niger." Applied and Environmental Microbiology, January 4, 2021. http://dx.doi.org/10.1128/aem.02701-20.
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Salicylic acid plays an important role in the plant immune response and its degradation is therefore important for plant pathogenic fungi. However, many non-pathogenic microorganisms can also degrade salicylic acid. In the filamentous fungi Aspergillus niger, two salicylic acid metabolic pathways have been suggested. The first pathway converts salicylic acid to catechol by a salicylate hydroxylase (ShyA). In the second pathway, salicylic acid is 3-hydroxylated to 2,3-dihydroxybenzoic acid followed by the decarboxylation to catechol by 2,3-dihydroxybenzoate decarboxylase (DhbA). A. niger cleaves the aromatic ring of catechol catalyzed by catechol 1,2-dioxygenase (CrcA) to form cis,cis-muconic acid. However, the identification and role of the genes and characterization of the enzymes involved in these pathways are lacking. In this study, we used transcriptome data of A. niger grown on salicylic acid to identify genes (shyA and crcA) involved in salicylic acid metabolism. Heterologous production in Escherichia coli followed by biochemical characterization confirmed the function of ShyA and CrcA. The combination of ShyA and CrcA demonstrated that cis,cis-muconic acid can be produced from salicylic acid. In addition, the in vivo roles of shyA, dhbA and crcA were studied by creating A. niger deletion mutants which revealed the role of these genes in the fungal metabolism of salicylic acid. Importance Nonrenewable petroleum sources are depleting and therefore alternative sources are needed. Plant biomass is one of the most abundant renewable sources on earth and is efficiently degraded by fungi. In order to utilize plant biomass efficiently, knowledge about the fungal metabolic pathways and the genes and enzymes involved is essential to create efficient strategies for producing valuable compounds such as cis,cis-muconic acid. cis,cis-muconic acid is an important platform chemical that is used to synthesize nylon, polyethylene terephthalate (PET), polyurethane, resins and lubricants. Currently, cis,cis-muconic acid is mainly produced through chemical synthesis from petroleum based chemicals. Here, we show that two enzymes from fungi can be used to produce cis,cis-muconic acid from salicylic acid and contributes 40 in creating alternative methods for the production of platform chemicals.
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Gajdoš, Peter, Veronika Urbaníková, Mária Vicenová, and Milan Čertík. "Enhancing very long chain fatty acids production in Yarrowia lipolytica." Microbial Cell Factories 21, no. 1 (July 11, 2022). http://dx.doi.org/10.1186/s12934-022-01866-6.
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Abstract Background Very long chain fatty acids (VLCFA) and their derivatives are industrially attractive compounds. The most important are behenic acid (C22:0) and erucic acid (C22:1Δ13), which are used as lubricants, and moisturizers. C22:0 and C22:1Δ13 have also potential for biofuel production. These fatty acids are conventionally obtained from plant oils. Yarrowia lipolytica is an oleaginous yeast with a long history of gene manipulations resulting in the production of industrially interesting compounds, such as organic acids, proteins, and various lipophilic molecules. It has been shown previously that it has potential for the production of VLCFA enriched single cell oils. Results The metabolism of Y. lipolytica was redesigned to achieve increased production of VLCFA. The effect of native diacylglycerol acyltransferases of this yeast YlLro1p, YlDga1p, and YlDga2p on the accumulation of VLCFA was examined. It was found that YlDga1p is the only enzyme with a beneficial effect. Further improvement of accumulation was achieved by overexpression of 3-ketoacyl-CoA synthase (TaFAE1) under 8UAS-pTEF promoter and blockage fatty acid degradation pathway by deletion of YlMFE1. The best-producing strain YL53 (Δmfe, pTEF-YlDGA1, 8UAS-pTEF-TaFAE1) produced 120 µg of very long chain fatty acids per g of produced biomass, which accounted for 34% of total fatty acids in biomass. Conclusions Recombinant strains of Y. lipolytica have proved to be good producers of VLCFA. Redesign of lipid metabolism pathways had a positive effect on the accumulation of C22:1Δ13 and C22:0, which are technologically attractive compounds.
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Saito, Taku. "The superficial zone of articular cartilage." Inflammation and Regeneration 42, no. 1 (May 2, 2022). http://dx.doi.org/10.1186/s41232-022-00202-0.
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AbstractThe superficial zone of articular cartilage contributes to smooth joint motion through the production of proteoglycan 4 (PRG4), also known as lubricin. Recent studies indicate novel effects of PRG4 as a signaling molecule, other than a simple extracellular matrix protein. Additionally, the accumulating evidence displays that various molecules and signaling pathways are involved in regulating the superficial zone and PRG4 expression. In addition, Prg4-expressing cells include a progenitor population of articular chondrocytes. Several non-clinical and clinical studies have shown that PRG4 and related molecules are promising candidates for disease-modifying drugs for treating osteoarthritis. Since PRG4 is also expressed in the synovium, tendons, and ligaments, further studies of PRG4-related pathways and PRG4-positive cells may elucidate the mechanisms underlying joint homeostasis.
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Hou, Xiaoxiao, Ziyu Wei, Christos C. Zouboulis, and Qiang Ju. "Aging in the sebaceous gland." Frontiers in Cell and Developmental Biology 10 (August 17, 2022). http://dx.doi.org/10.3389/fcell.2022.909694.
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Sebaceous glands (SGs) originate from hair follicular stem cells and secrete lipids to lubricate the skin. The coordinated effects of intrinsic and extrinsic aging factors generate degradation of SGs at a late age. Senescence of SGs could be a mirror of the late aging of both the human body and skin. The procedure of SG aging goes over an initial SG hyperplasia at light-exposed skin areas to end with SG atrophy, decreased sebum secretion, and altered sebum composition, which is related to skin dryness, lack of brightness, xerosis, roughness, desquamation, and pruritus. During differentiation and aging of SGs, many signaling pathways, such as Wnt/β-catenin, c-Myc, aryl hydrocarbon receptor (AhR), and p53 pathways, are involved. Random processes lead to random cell and DNA damage due to the production of free radicals during the lifespan and neuroendocrine system alterations. Extrinsic factors include sunlight exposure (photoaging), environmental pollution, and cigarette smoking, which can directly activate signaling pathways, such as Wnt/β-catenin, Notch, AhR, and p53 pathways, and are probably associated with the de-differentiation and hyperplasia of SGs, or indirectly activate the abovementioned signaling pathways by elevating the inflammation level. The production of ROS during intrinsic SG aging is less, the signaling pathways are activated slowly and mildly, and sebocytes are still differentiated, yet terminal differentiation is not completed. With extrinsic factors, relevant signaling pathways are activated rapidly and fiercely, thus inhibiting the differentiation of progenitor sebocytes and even inducing the differentiation of progenitor sebocytes into keratinocytes. The management of SG aging is also mentioned.
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"Correction for Balakrishnan et al., Novel pathways for fuels and lubricants from biomass optimized using life-cycle greenhouse gas assessment." Proceedings of the National Academy of Sciences 112, no. 29 (June 23, 2015): E3969. http://dx.doi.org/10.1073/pnas.1511659112.
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"Sexual Function and Depressive Symptoms in Middle-Aged Women with LongLasting Type 1 Diabetes – A Cross-Sectional Study." Journal of Nursing & Healthcare 6, no. 2 (April 26, 2021). http://dx.doi.org/10.33140/jnh.06.02.03.
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Background & aim: Women and men with diabetes, type 1 (T1D) and type 2 (T2D) develop complications in small and large blood vessels as well as in nerve pathways over time. In men, erectile dysfunction is a well-documented complication. However, sexual dysfunction in women with different types of diabetes is less studied. Sexual dysfunction is associated with lowered health-related quality of life and depression. The aim of the study was to investigate self-reported sexual function and signs of depression in middle-aged women with long-lasting T1D. Methods: A cross-sectional questionnaire study including the Female Sexual Function Index (FSFI) and the Patient Health Questionnaire (PHQ-9) together with background questions was designed. The sample was women aged 45-66 with T1D for at least 15 years, identified from clinical medical records at four hospitals in southern Sweden. Descriptive statistical analysis of background factors, depression, and self-reported sexual dysfunction, as well as correlation and regression analysis, are presented. Results: A total of 212 women completed the questionnaire, mean age 54.1 (SD: 5.83), mean years with T1D 36.2 (SD: 11.42). Almost half of the women had sexual dysfunction (45.2%; FSFI < 26.55, max 36) and the mean full score was 23.73 (SD: 10.57). The FSFI domains are desire, arousal, lubrication, orgasm, satisfaction and pain. Symptoms of depression measured by PHQ-9 were reported by 39.8%. A low FSFI was significantly associated with severe depression (p<0.001). Conclusions: Problems with sexual dysfunction and depression in middle-aged women with long-lasting T1D are common and may be unreported unless addressed in clinical care. Nurses could start asking women about problems with lubrication and vaginal pain in relation to sexual activity. Lubricants or local estrogen therapy could prevent those problems. Routinely assessing depressive status is equally important in improving quality of life for women with T1D.
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Cimini, C., N. Bernabò, M. Ramal-Sanchez, A. Taraschi, R. Belda-Perez, L. Valbonetti, G. Capachietti, et al. "P-109 Nanoflakes of molybdenum disulfide functionalized with catechins modulate the sperm capacitation resulting in an improvement of the IVF outcomes in a swine in vitro model." Human Reproduction 37, Supplement_1 (June 29, 2022). http://dx.doi.org/10.1093/humrep/deac107.105.
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Abstract Study question Are there any potential effects derived from the exposure of spermatozoa to MoS2/catechins nanoflakes during the process of capacitation? Summary answer The spermatozoa exposure to MoS2/catechin nanoflakes do not induce toxicity on spermatozoa and modulate sperm capacitation in a swine in vitro model. What is known already Molybdenum disulfide (MoS2)is a 2D graphene-like material widely used in a pletora of applications, such as energy storage, catalysts, sensors, lubricants and friction reducers. The unique features of this nanomaterial suggest interesting applications in the biomedical field. To date, there are no data regarding the potential effects of MoS2 nanoflakes on the reproductive field. Study design, size, duration To evaluate the potential effects derived from the interaction between the sperm cells and this material, spermatozoa were exposed to MoS2/Catechins nanoflakes at 10, 1, 0.1 ppm, using catechins as control, during capacitation. Different sperm capacitation events were studied, mainly related to their physic-chemical properties (membrane) and biochemical pathways (intracellular signaling), and then IVF experiments were performed with MoS2/catechins and catechins (0.1 ppm). Ten independent experiments were carried out between November 2020 and November 2021. Participants/materials, setting, methods The sonochemical exfoliation of bulk MoS2 in water-soluble MoS2 nanoflakes was obtained with a flavonoid, catechin (CT), that acts as stabilizing agent remaining anchored onto the surface of the MoS2 sheets. Sperm cells from different animals were included in this study. To evaluate the parameters exposed, different techniques were used: fluorescence microscopy, flow cytometry, western blot and in vitro fertilization assay. Main results and the role of chance No significant differences were found in terms of sperm membrane modifications (acrosome damage and membrane disorder) and sperm biochemical pathways (PKA activity, tyrosine phosphorylation patterns, intracellular calcium concentration and mitochondrial activity) between the groups of study compared to the control group. From the results arise that MoS2/CT nanoflakes do not induce any negative effect on the parameters evaluated related to sperm capacitation. Moreover, the addition of MoS2/CT nanoflakes and CT alone at a specific concentration (0.1 ppm) has demonstrated to increase the spermatozoa fertilizing ability in an IVF assay by increasing the number of fertilized oocytes with respect to the control group. Limitations, reasons for caution Despite the promising results in terms of IVF outcomes, further studies are needed to investigate the nature of the interaction between spermatozoa and the MoS2, as well as the potential effects on embryonic development. Wider implications of the findings Our findings open new interesting perspectives regarding the use of 2D graphene-like materials obtained using natural/bio compounds, to implement new strategies to manage sperm capacitation. Trial registration number not applicable