Presence Of Oleic Acid Research Articles

The role of membrane physiology in sHSP Lo18-lipid interaction and lipochaperone activity

To cope with environmental stresses, organisms, including lactic acid bacteria such as O. oeni, produce stress proteins called HSPs. In wine, O. oeni is constantly confronted by stress affecting its membrane fluidity. To survive through in these deleterious conditions, O. oeni synthesizes Lo18, a unique, small HSP which acts as a molecular chaperone and a lipochaperone. The molecular mechanism underlying its lipochaperone activity, particularly regarding membrane lipid composition, remains poorly understood. In this context, Lo18 lipochaperone activity and the associated modification in protein structure were studied during interaction with different liposomes from O. oeni cultures representing unstressed, stressed and stressed-adapted physiological states. The results showed that the presence of the membrane (whatever its nature) induces a modification of Lo18’s structure. Also, the presence of oleic acid and/or phosphatidylglycerol is important to favor Lo18-membrane interaction, allowing lipochaperone activity. This research enhances understanding of sHSP-membrane interactions in bacterial systems.

The Bbotf1 Zn(Ⅱ)2Cys6 transcription factor contributes to antioxidant response, fatty acid assimilation, peroxisome proliferation and infection cycles in insect pathogenic fungus Beauveria bassiana

The abilities to withstand oxidation and assimilate fatty acids are critical for successful infection by many pathogenic fungi. Here, we characterized a Zn(II)2Cys6 transcription factor Bbotf1 in the insect pathogenic fungus Beauveria bassiana, which links oxidative response and fatty acid assimilation via regulating peroxisome proliferation. The null mutant ΔBbotf1 showed impaired resistance to oxidants, accompanied by decreased activities of antioxidant enzymes including CATs, PODs and SODs, and down-regulated expression of many antioxidation-associated genes under oxidative stress condition. Meanwhile, Bbotf1 acts as an activator to regulate fatty acid assimilation, lipid and iron homeostasis as well as peroxisome proliferation and localization, and the expressions of some critical genes related to glyoxylate cycle and peroxins were down-regulated in ΔBbotf1 in presence of oleic acid. In addition, ΔBbotf1 was more sensitive to osmotic stressors, CFW, SDS and LDS. Insect bioassays revealed that insignificant changes in virulence were seen between the null mutant and parent strain when conidia produced on CZP plates were used for topical application. However, propagules recovered from cadavers killed by ΔBbotf1 exhibited impaired virulence as compared with counterparts of the parent strain. These data offer a novel insight into fine-tuned aspects of Bbotf1 concerning multi-stress responses, lipid catabolism and infection cycles.

Influence of arylalkyl amines on the formation of hybrid CsPbBr3 nanocrystals via a modified LARP method.

Perovskite nanocrystals have attracted much attention in the last ten years due to their different applications, especially in the photovoltaic domain and LED performance. In this large family of perovskite nanocrystals, CsPbBr3 nanocrystals are attractive nanomaterials because they are good candidates for obtaining green emissions and exploring new synthesis routes. In this context, controlling the nanometric scale's morphology, particularly the size and monodispersity, is fundamental for exploring their photophysical properties and final applications. Currently, the nanometric size of nanocrystals is ensured by the presence of oleic acid and oleylamine molecules, in using Hot Injection (HI) or ligand-assisted reprecipitation (LARP) methods. If oleic acid plays a fundamental role, oleylamine can be easily substituted by other amino molecules, opening the way for the functionalization of CsPbBr3 nanocrystals and the obtention of new hybrid perovskite nanocrystal families. In this article, we describe the synthesis, by soft chemistry, of a new family of hybrid organic-inorganic CsPbBr3 nanocrystals, functionalized by aryl-alkylamine (AAA) molecules, through the modified LARP method. We highlight the mechanism for cutting submicron crystals into nanocrystals, using aryl-alkylamine molecules like scissors. The impact of these amino molecules on the final nanocrystals leads to different nanocrystal morphologies (nanocubes, nanosheets, or nanorods) and structures (monoclinic, rhombohedral, or tetragonal). In addition, this modified LARP method highlights, under certain experimental conditions, an unexpected formation of PbO ribbons.

Striking effect of the iron stearate purity on the shape and size of maghemite nanoparticles

In general, the synthesis of maghemite nanoparticles (NPs) by thermal decomposition of commercially available iron stearate precursors, in the presence of oleic acid, yields spherical nanoparticles. However, we show in this article that the synthesis of NPs from commercially available precursors (Commercial grade and washed) results in the formation of uniformly monodisperse triangular or cubic NPs. Spherical NPs result only from the precursors synthesized in the laboratory. The detailed Energy Dispersive X-ray spectrometry (EDS) and X-ray diffraction analysis performed on the commercial precursors (Commercial grade and washed) reveal the presence of impurities: sodium stearate and/or sodium chloride (NaCl). This result highlights the importance of iron stearate precursor origin (commercial grade or washed or home-made) in terms of reproducibility and growth of iron oxide NPs, giving rise to either monodisperse spherical, cubic, or triangular NPs. We emphasize that this finding majorly affects the development of NPs and also our understanding of the NP growth mechanisms, which can be biased if we do not account for this additional key parameter among all the ones involved in the colloidal synthesis. The formation of the triangular nanoparticles in the conditions we use has never been reported. Further, the formation of both cubic and triangular NPs has been discussed in terms of selective adsorption on the growing NP of sodium stearate, sodium, and chloride salts.

Growth of Enterococcus faecalis ∆plsX strains is restored by increased saturated fatty acid synthesis.

The Enterococcus faecalis acyl-acyl carrier protein (ACP) phosphate acyltransferase PlsX plays an important role in phospholipid synthesis and exogenous fatty acid incorporation. Loss of plsX almost completely blocks growth by decreasing de novo phospholipid synthesis, which leads to abnormally long-chain acyl chains in the cell membrane phospholipids. The ∆plsX strain failed to grow without supplementation with an appropriate exogenous fatty acid. Introduction of a ∆fabT mutation into the ∆plsX strain to increase fatty acid synthesis allowed very weak growth. The ∆plsX strain accumulated suppressor mutants. One of these encoded a truncated β-ketoacyl-ACP synthase II (FabO) which restored normal growth and restored de novo phospholipid acyl chain synthesis by increasing saturated acyl-ACP synthesis. Saturated acyl-ACPs are cleaved by a thioesterase to provide free fatty acids for conversion to acyl-phosphates by the FakAB system. The acyl-phosphates are incorporated into position sn1 of the phospholipids by PlsY. We report the tesE gene encodes a thioesterase that can provide free fatty acids. However, we were unable to delete the chromosomal tesE gene to confirm that it is the responsible enzyme. TesE readily cleaves unsaturated acyl-ACPs, whereas saturated acyl-ACPs are cleaved much more slowly. Overexpression of an E. faecalis enoyl-ACP reductase either FabK or FabI which results in high levels of saturated fatty acid synthesis also restored the growth of the ∆plsX strain. The ∆plsX strain grew faster in the presence of palmitic acid than in the presence of oleic acid with improvement in phospholipid acyl chain synthesis. Positional analysis of the acyl chain distribution in the phospholipids showed that saturated acyl chains dominate the sn1-position indicating a preference for saturated fatty acids at this position. High-level production of saturated acyl-ACPs is required to offset the marked preference of the TesE thioesterase for unsaturated acyl-ACPs and allow the initiation of phospholipid synthesis.

Oleic acid improves the conidial production and quality of Metarhizium rileyi as a biocontrol agent

ABSTRACT Metarhizium rileyi is a biological agent used in the control of various pests, particularly noctuid insects. However, this fungal species is slow-growing, resulting in a prolonged culture period and limiting its commercial production. In this study, 0.3% (w/w) oleic acid significantly enhanced the rates of hyphal growth, conidial production, and conidial germination by 23%, 9%, and 10%, respectively. The expression of genes related to microbial growth and development (MrPbs2, MrMsn2, MrSwi6, MrNsdD, Mrap1 and MrSte12) was significantly increased in the presence of oleic acid. The M. rileyi conidial production and its effects on the mortality of Spodoptera frugiperda were investigated using rice-vegetable oil solid medium (RVOSM) and its substitute Sabouraud maltose agar plus yeast extract (SMAY) plates containing 0.03% oleic acid. The fungi retained their toxicity to S. frugiperda. Therefore, oleic acid can improve the growth potential of fungi, and RVOSM can be used as a substrate for conidia production for the application of M. rileyi as a biocontrol agent.

Tunable particle-agglomeration and magnetic coupling in bi-magnetic nanocomposites.

A set of non-stoichiometric Zn-Co-ferrite nanoparticles (NPs) was prepared by thermal decomposition of metallic complexes, in the presence of oleic acid, and, after a ligand-exchange process, was coated by a hydrophilic surfactant: these NPs were used as seeds in a sol-gel self-combustion synthesis to prepare nanocomposites (NCs) with a fixed weight ratio. Our focus here is the development of an efficient synthetic approach to control the magnetic coupling between a hard-magnetic matrix (Sr-ferrite) and NPs. The physico-chemical synthetic conditions (temperature, pH, colloidal stability) were optimized in order to tune their effect on the final particles' agglomeration in the matrix. We demonstrate that our synthetic approach is a novel way to produce strongly magnetically coupled NCs, where the final extrinsic properties could be tuned by controlling (i) the agglomeration of seeds in the matrix and (ii) their elemental doping.

Development of skin sebum medium and inhibition of lipase activity in Cutibacterium acnes by oleic acid.

Cutibacterium acnes is associated with the exacerbated inflammation of acne vulgaris, which occurs through the immune induction and pathogenicity factor production. Sebum, which is not present in the growth medium currently used to study acne, is present in acne pustules in differing concentrations among the pathological stages, such as the initial formation and inflammatory phase. To evaluate the effect of C. acnes on inflammation exacerbation in acne pustules in vitro, we developed an skin sebum medium containing artificial sebum and studied the growth and pathogenicity factor production of C. acnes in the skin sebum medium. The growth and lipase activity of C. acnes ATCC11828 were tested using skin sebum medium containing different sebum concentrations. Only lipase activity decreased in the skin sebum medium culture containing 0.5 % sebum when compared with that without sebum, while both growth and lipase activity decreased in cultures with 1.0 % sebum. Therefore, the growth and lipase activity of C. acnes changed in the presence of sebum. Furthermore, when the growth and lipase activity of C. acnes were tested in skin sebum medium containing sebum components, unsaturated fatty acids, such as oleic acid and triolein, led to a decrease in lipase activity without inducing a change in growth. In the presence of oleic acid, C. acnes lipase activity decreased noncompetitively in a concentration-dependent manner. Our data showed that C. acnes growth and lipase activity changed upon sebum addition to the skin sebum medium, and acne inflammation caused by C. acnes needs to be studied under conditions similar to those in acne pustules.

Mini AuAg Wavy Nanorods Displaying Plasmon‐Induced Photothermal and Photocatalytic Properties

Alloyed AuAg wavy nanorods (wNRs) of ≈24.0 nm length and 3.5 nm width are formed by the mild decomposition of the organometallic complex [Au2Ag2(C6F5)4(OEt2)2]n in tetrahydrofuran (THF) in the presence of oleic acid. Ligand exchange with l‐glutathione (GSH) or poly(ethylene glycol) methyl ether thiol (PEG‐SH) leads to water‐soluble nanostructures. These AuAg wNRs display tunable size‐dependent longitudinal localized surface plasmon resonance (l‐LSPR) broad absorptions beyond 750 nm in the near‐infrared (NIR) I and II regions. These intense plasmonic absorptions lead to interesting photothermal, catalytic, and photocatalytic properties, including the catalytic reduction of 4‐nitrophenol, the photocatalytic reduction of 4‐nitrostyrene, or the photocatalytic dehydrogenation of ammonia borane for H2 release.

Water‐dispersible Gadolinium Oxide Nanoplates as an Effective Positive Magnetic Resonance Imaging Contrast Agent

AbstractGadolinium oxide (Gd2O3) nanoplates have been successfully synthesized by thermal decomposition method in the presence of oleic acid and oleylamine as surfactants. As a result, the nanoplates have average edge length and thickness around 10 nm and 1.1 nm, respectively. The hydrophobic OA/OM capped Gd2O3 nanoplates were encapsulated with amphiphilic poly (maleic anhydride‐alt‐1‐octadecene) polymer (PMAO) for phase transfer into aqueous media. The obtained Gd2O3@PMAO showed a hydrodynamic size of 32 nm with good dispersion in water solvent and stable in wide range of pH (pH=2÷11) and at electrolyte concentrations as high as NaCl 380 mM. In addition, the in vitro toxicity tests confirmed the biocompatibility of Gd2O3@PMAO nanoplates. The magnetic resonance imaging (MRI) result exhibited the r1 of Gd2O3@PMAO nanoplates (16.95 mM−1s−1) is four times higher than that of clinically used Gd‐DTPA. These results suggest that the PMAO coated ‐Gd2O3 nanoplates are potential T1 contrast agents for in vivo MRI application.

Controlling Cation Distribution and Morphology in Colloidal Zinc Ferrite Nanocrystals.

This paper describes the first synthetic method to achieve independent control over both the cation distribution (quantified by the inversion parameter x) and size of colloidal ZnFe2O4 nanocrystals. Use of a heterobimetallic triangular complex of formula ZnFe2(μ3-O)(μ2-O2CCF3)6(H2O)3 as a single-source precursor, solvothermal reaction conditions, absence of hydroxyl groups from the reaction solvent, and the presence of oleylamine are required to achieve well-defined, crystalline, and monodisperse ZnFe2O4 nanoparticles. The size of the ZnFe2O4 nanocrystals increases as the ratio of oleic acid and oleylamine ligands to precursor increases. The inversion parameter increases with increasing solubility of the precursor in the reaction solvent, with the presence of oleic acid in the reaction mixture, and with decreasing reaction temperature. These results are consistent with a mechanism in which ligand exchange between oleic acid and carboxylate ligands bound to the precursor complex influences the degree to which the reaction produces a kinetically trapped or thermodynamically stable cation distribution. Importantly, these results indicate that preservation of the triangular Zn–O–Fe2 core structure of the precursor in the reactive monomer species is crucial to the production of a phase-pure ZnFe2O4 product and to the ability to tune the cation distribution. Overall, these results demonstrate the advantages of using a single-source precursor and solvothermal reaction conditions to achieve synthetic control over the structure of ternary spinel ferrite nanocrystals.

Pseudomonas aeruginosa Secretes the Oxylipin Autoinducer Synthases OdsA and OdsB via the Xcp Type 2 Secretion System.

The oxylipin-dependent quorum-sensing system (ODS) of Pseudomonas aeruginosa relies on the production and sensing of two extracellular oxylipins, 10S-hydroxy-(8E)-octadecenoic acid (10-HOME) and 7S,10S-dihydroxy-(8E)-octadecenoic acid (7,10-DiHOME). Here, we implemented a genetic screen of P. aeruginosa strain PAO1 aimed to identify genes required for 10-HOME and 7,10-DiHOME production. Among the 14 genes identified, four encoded previously known components of the ODS and 10 encoded parts of the Xcp type II secretion system (T2SS). We subsequently created a clean xcpQ deletion mutant, which encodes the necessary outer membrane component of Xcp, and found it recapitulated the impaired functionality of the T2SS transposon mutants. Further studies showed that the ΔxcpQ mutant was unable to secrete the oxylipin synthase enzymes across the outer membrane. Specifically, immunoblotting for OdsA, which is responsible for the generation of 10-HOME from oleic acid, detected the enzyme in supernatants from wild-type PAO1 but not ΔxcpQ cultures. Likewise, chromatography of supernatants found that 10-HOME was not in supernatants collected from the ΔxcpQ mutant. Accordingly, diol synthase activity was increased in the periplasm of ΔxcpQ mutant consistent with a stoppage in its transport. Importantly, after exposure of the ΔxcpQ mutant to exogenous 10-HOME and 7,10-DiHOME, the ODS effector genes become active; thus, the sensing component of the ODS does not involve the T2SS. Finally, we observed that Xcp contributed to robust in vitro and in vivo biofilm formation in oleic acid availability- and ODS-dependent manner. Thus, T2SS-mediated transport of the oxylipin synthase enzymes to outside the bacterial cell is required for ODS functionality. IMPORTANCE We previously showed that the ODS of P. aeruginosa produces and responds to oxylipins derived from host oleic acid by enhancing biofilm formation and virulence. Here, we developed a genetic screen strategy to explore the molecular basis for oxylipins synthesis and detection. Unexpectedly, we found that the ODS autoinducer synthases cross the outer membrane using the Xcp type 2 secretion system (T2SS) of P. aeruginosa, and so the biosynthesis of oxylipins occurs extracellularly. T2SS promoted biofilm formation in the presence of oleic acid as a result of ODS activation. Our results identify two new T2SS secreted proteins in P. aeruginosa and reveal a new way by which this important opportunistic pathogen interacts with the host environment.

Scuffing resistance of polyalphaolefin (PAO)-based nanolubricants with oleic acid (OA) and iron oxide nanoparticles

The development and application of nanolubricants has shown great potential to reduce friction and wear, especially in the automotive field for systems operating under boundary and mixed lubrication regimes. The search for additives that do not attack the environment has motivated the use of nanoparticles, especially metallic oxides, because of their characteristics such as low toxicity, high surface area, high wettability, and easy dispersion. The objective of this work was to evaluate the addition of iron oxide nanoparticles as additive to pure PAO 8 base oil. The nanoparticle action mechanisms, lubrication efficiency, friction, and wear rates were evaluated. The concentration of nanoparticles in the oil and the addition of oleic acid as a dispersing agent were varied. The synthesis of the nanoparticles was done by aqueous precipitation; characterization was performed by XRD, FTIR, Raman and SEM analyses. Tribological tests were performed in a reciprocating tribometer (Plint TE 67) using AISI 1020 prismatic samples and AISI 52100 chrome steel balls of 5 mm diameter. Test conditions resulted in boundary lubrication regime, for a starved contact with limited lubricant supply (0.5 µL). Concentrations of 0.4 and 1.6 wt% of nanoparticles were added to the base oil with and without the presence of oleic acid. Friction coefficient was not sensitive to the presence of nanoparticles, with statistically similar values for all the fluids tested. On the other hand, the presence of nanoparticles increased scuffing resistance and reduced wear rates. The lubricants with nanoparticles proved able to withstand relatively high loads, keeping the friction coefficient low for longer test durations due to the formation of protective tribolayers between the worn surfaces. The addition of nanoparticles reduced wear rates by around 27% when compared to tests using pure PAO 8.

Electronic transition pathways in energy transfer processes for upconversion photoluminescence of Yb3+/Ho3+ co-doped NaLa(MoO4)2 microcrystals

In recent years, upconversion photoluminescent micro/nanocrystals with unique anti-Stokes luminescence properties have shown high application value in many relevant fields. In this work, pure tetragonal phase NaLa(MoO4)2:Yb3+/Ho3+ microspheres have been synthesized by a solvothermal method in the presence of oleic acid and 1-octadecene. Under the excitation of 980 nm laser, NaLa(MoO4)2:Yb3+/Ho3+ microcrystals emit red, green and near infrared upconversion luminescence with peak wavelengths at 660/643 nm, 541 nm, and 756 nm. Based on the analysis of excitation power-dependent upconversion luminescence intensities and energy level diagram of Yb3+/Ho3+, electronic transition pathways in the energy transfer processes for upconversion luminescence of NaLa(MoO4)2:Yb3+/Ho3+ microcrystals are studied. For red upconversion luminescence at 660/643 nm, the predominant population pathway to state 5F5 (Ho3+) is “Yb3+ (2F5/2) + Ho3+ (5I7) → Yb3+ (2F7/2) + Ho3+ (5F5)”. While, “Yb3+ (2F5/2) + Ho3+ (5I6) → Yb3+ (2F7/2) + Ho3+ (5F4/5S2)” process accounts for the population of state 5F4/5S2 (Ho3+) for radiative transitions of upconversion luminescence at 541 and 756 nm. Energy back transfer contributes to the intense red upconversion luminescence at 660/643 nm. These electronic transition pathways in energy transfer processes are further confirmed by the analyses based on energy level mismatch and luminescent lifetimes.

Engineering an oleic acid-induced system for Halomonas, E. coli and Pseudomonas

Ligand-induced system plays an important role for microbial engineering due to its tunable gene expression control over timings and levels. An oleic acid (OA)-induced system was recently constructed based on protein FadR, a transcriptional regulator involved in fatty acids metabolism, for metabolic control in Escherichia coli. In this study, we constructed a synthetic FadR-based OA-induced systems in Halomonas bluephagenesis by hybridizing the porin promoter core region and FadR-binding operator (fadO). The dynamic control range was optimized over 150-fold, and expression leakage was significantly reduced by tuning FadR expression and positioning fadO, forming a series of OA-induced systems with various expression strengths, respectively. Additionally, ligand orthogonality and cross-species portability were also studied and showed highly linear correlation among Halomonas spp., Escherichia coli and Pseudomonas spp. Finally, OA-induced systems with medium- and small-dynamic control ranges were employed to dynamically control the expression levels of morphology associated gene minCD, and monomer precursor 4-hydroxybutyrate-CoA (4HB-CoA) synthesis pathway for polyhydroxyalkanoates (PHA), respectively, in the presence of oleic acid as an inducer. As a result, over 10 g/L of poly-3-hydroxybutyrate (PHB) accumulated by elongated cell sizes, and 6 g/L of P(3HB-co-9.57 mol% 4HB) were obtained by controlling the dose and induction time of oleic acid only. This study provides a systematic approach for ligand-induced system engineering, and demonstrates an alternative genetic tool for dynamic control of industrial biotechnology.

The Enterococcus faecalis FabT Transcription Factor Regulates Fatty Acid Biosynthesis in Response to Exogeneous Fatty Acids.

The phospholipid acyl chains of Enterococcus faecalis can be derived either by de novo synthesis or by incorporation of exogenous fatty acids through the fatty acid kinase complex (Fak)-phosphate acyltransferase (PlsX) pathway. Exogenous fatty acids suppress fatty acid synthesis through the transcriptional repressor FabT, the loss of which eliminated regulation of de novo fatty acid biosynthesis and resulted in decreased incorporation of exogenous unsaturated fatty acids. Purified FabT bound to the promoters of several fatty acid synthesis genes that contain a specific palindromic sequence and binding was enhanced by acylated derivatives of acyl carrier protein B (acyl-AcpB). The loss of the PlsX pathway blocked FabT-dependent transcriptional repression in the presence of oleic acid. Transcriptional repression was partially retained in a E. faecalis ΔacpB strain which showed decreased fatty acid biosynthesis in the presence of exogenous unsaturated fatty acids. The FabT-dependent activity remaining in the ΔacpB strain indicates that acylated derivatives of AcpA were weak enhancers of FabT binding although AcpA is believed to primarily function in de novo fatty acid synthesis.

A Near-Infrared Probe for Specific Imaging of Lipid Droplets in Living Cells.

Lipid droplets (LDs) are involved in various physiological processes and associated with cancer development, and are regarded as a potential tumor marker for cancer diagnosis. Monitoring LDs is of prior importance to understand their involvement in biological mechanisms and the early detection of cancers. Highly sensitive and specific noninvasive fluorescent probes are particularly desirable for imaging LDs and cancer diagnosis. Herein, according to the high-viscosity and low-polarity microenvironment in LDs, we developed four easily prepared LDs-specific probes based on noncharged merocyanines. Among them, LD-1 absorbs and emits in the near-infrared (NIR) region with a large Stokes shift. Importantly, LD-1 displayed high sensitivity to high viscosity and low polarity, which allowed it to show high LDs-targeting ability. In cell imaging, LD-1 successfully probed the changes in LDs in the presence of oleic acid or during ferroptosis and was used to distinguish cancer cells from normal cells.

Effect of geographical origin on lipid content and fatty acids composition of bee collected pollen

Among the essential nutrients found in bee pollen, lipids comprise one of its principal and widely researched compounds with variable content and fatty acids composition depending on pollen’s botanical and geographical origin. Although plant source effect on pollen lipids has been partially studied, the impact of geographical origin remains unclear and also, the analysis of polyfloral pollen samples from diverse regions may lead to inaccurate results. Thus, in the present study, monofloral bee pollen samples, Cistus criticus, and Sinapis arvensis, were collected from different areas to identify the effect of geographical origin on pollen lipid profile, excluding the impact of botanical origin. The total lipid content of Cistus pollen ranged from 2.50% to 3.24% and of Sinapis pollen from 7.64% to 9.06%, while statistically significant differences were found among the studied areas, both for the two species. However, it seems that regardless of origin, Sinapis pollen is a rich source of total lipid content, contrary to Cistus pollen. Likely, it was found that geographical origin affected their fatty acid composition. The presence of oleic acid (cis C18:1) was dominant in all Cistus pollen samples and ranged from 50.75% (Central Macedonia) to 65.78% (Attiki), while all Sinapis pollen samples exhibited high content of alpha-linolenic acid (C18:3), with the low average percentage (41.71%) found in Crete and the highest (52.94%) in Central Macedonia. The results showed that the determination of geographical origin effect on lipids profile of bee pollen should be considered for the establishment of global quality criteria.

Highly stable mixed halide perovskite quantum dots synthesized in the presence of fluorous ligands

AbstractThis work probes the potential of fluorous fatty acids as stabilizing ligands in the synthesis of mixed halide perovskite quantum dots (MHP QDs). Traditionally, MHP QDs are synthesized in the presence of oleic acid (OA) and oleyl amine (OAm). Here fluorous fatty acids have been used along with OA and OAm to yield MHP QDs with higher stability. Increased fractions of fluorous molecules in reaction mixture require the process to be carried out at a higher temperature due to the distinctive temperature‐dependent mixing behavior of perfluorinated ligands. Best of fluorous acid functionalized QDs in solution showed a 9% decrease in their photoluminescence quantum yield (PLQY) over 30 days compared to 27% in those without. The composition of fluorous fatty acids during synthesis influences the size, form and optical properties of MHP QDs. Further in situ addition of non‐carboxylic acid fluorous ligands (thiols) are also shown to the give similar improvements in stability and optical properties of MHP QDs. The in situ fluorous ligand functionalization studied in this work presents a new method to improve the stability of MHP‐QD while providing a thermally controlled handle to tune the structure of nanoparticle films.

CHARACTERIZATION OF MALAYSIAN JATROPHA SEED OIL USING FTIR AND GCMS

Flow assurance problems such as wax deposition impacted the oil and gas industry in various points of oil transport hence a cure is widely researched. This paper aims to establish a cure by using Jatropha curcas seed oil (non-edible) originated from Malaysia and its sustainability as a wax inhibitor component. Extraction and characterization of Jatropha seed oil using Fourier Transform Infrared Spectroscopy (FTIR) and Gas Chromatography-Mass Spectrometry (GCMS) were conducted to identify the properties of Jatropha seed oil such as the presence of oleic acid which is the main component required in wax inhibitor. Jatropha seed oil extraction was conducted using a soxhlet extractor and n-Hexane solvent which was heated at 70°C. The obtained results illustrated that at the peak of 1746.48 cm–1, FTIR analysis indicated the presence of C=O stretching carboxyl which was the ester fatty acid group while at a retention time of 36.834 min, 44.91% of the oleic acid was present via GCMS analysis. The analysis revealed the presence of high oleic acid in Jatropha seed oil has great potential as wax inhibitor to improve the flowability retarded by wax precipitation.Keywords: Jatropha seed oil, fatty acid, oleic acid, wax inhibitor, soxhlet extractor