Number Of Double Bonds Research Articles

Strategy for Global Profiling and Identification of 2- and 3-Hydroxy Fatty Acids in Plasma by UPLC–MS/MS

2-Hydroxy fatty acids (2-OHFAs) and 3-hydroxy fatty acids (3-OHFAs) with the same carbon backbone are isomers, both of which are closely related to diseases involving fatty acid oxidation disorder. However, the comprehensive profiling of 2- and 3-OHFAs remains an ongoing challenge due to their high structure similarity, few structure-informative product ions, and limited availability of standards. Here, we developed a new strategy to profile and identify 2- and 3-OHFAs according to structure-dependent retention time prediction models using ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Both accurate MS and MS/MS spectra were collected for peak annotation by comparison with an in-house database of theoretically possible 2- and 3-OHFAs. The structures were further confirmed by the validated structure-dependent retention time prediction models, taking advantage of the correlation between the retention time, carbon chain length and number of double bonds, as well as the hydroxyl position-induced isomeric retention time shift rule. With the use of this strategy, 18 2-OHFAs and 32 3-OHFAs were identified in the pooled plasma, of which 7 2-OHFAs and 20 3-OHFAs were identified for the first time in this work, furthering our understanding of OHFA metabolism. Subsequent quantitation method was developed by scheduled multiple reaction monitoring (MRM) and then applied to investigate the alteration of 2- and 3-OHFAs in esophageal squamous cell carcinoma (ESCC) patients. Finally, a potential biomarker panel consisting of six OHFAs with good diagnostic performance was achieved. Our study provides a new strategy for isomer identification and analysis, showing great potential for targeted metabolomics in clinical biomarker discovery.

The relationship between liver triglyceride composition and proton density fat fraction as assessed by 1 H MRS.

The aim of this study was to estimate parameters determining liver triglyceride composition (TC) using 1 H MRS and to assess how TC estimability is affected by proton density fat fraction (PDFF) in adults with nonalcoholic fatty liver disease (NAFLD). In this prospective single-site study, 199 adults with known or suspected NAFLD in whom other causes of liver disease were excluded underwent two 1 H MRS STimulated Echo Acquisition Method (STEAM) sequences at 3 T. A respiratory-gated water-suppressed free breathing sequence (TE 10 ms, 16 signal averages) was used to assess TC in terms of the number of double bonds (ndb) and methylene-interrupted double bonds (nmidb), and a single breath-hold-long TR, multi-TE sequence (TR 3500 ms), which acquired five single average spectra over TE 10-30 ms, was used to estimate liver PDFF. Ndb and nmidb estimability was qualitatively assessed for each case and summarized descriptively. The consistency of ndb and nmidb estimation was examined using ROC analysis. The relationship between ndb and nmidb values and PDFF was presented graphically. Quality-of-fit of ndb and nmidb versus PDFF was evaluated by Pearson-r correlation. A significance level of 0.05 was used. In 263 1 H MRS examinations performed on 199 adult participants, ndb and nmidb were successfully estimated in 7/53 (13.2%) examinations with PDFF < 4%, 13/30 (43.3%) examinations with PDFF between 4% and 7%, 33/41 (80.5%) examinations with PDFF between 7% and 10%, and 124/139 (89.2%) examinations with PDFF > 10% (maximum PDFF 38.1%). Liver TC could be estimated consistently for PDFF > 6.7%. Both ndb and nmidb decreased with increasing PDFF (ndb = 2.83-0.0160·PDFF, r = -0.449, P < 0.0001); nmidb = 0.75-0.0088·PDFF, r = -0.350, P < 0.0001). In a cohort of adults with known or suspected NAFLD, liver TC becomes more saturated as PDFF increases.

The main differences in reactivity of mono- and diunsaturated fatty acid esters during aerobic oxidation

During the aerobic oxidation of esters of both mono- and diunsaturated fatty acids and their mixtures, epoxide compounds are first forming, as well as the peroxide compounds with different structures and reactivities depending on the number of double bonds in the original molecule. The mild aerobic oxidation conditions in the column-type apparatus led to a number of features of the process. It was shown that both types of esters are consumed in independent ways, despite the fact that the whole process is radical. Therefore, this means the absence of processes of transfer of oxidation chains, as well as the chains of radical reactions themselves. Thus, we can conclude that the process under study is radical without chain transfer from one type of ester to another. Peroxides forming from monounsaturated fatty acid esters are able to participate in catalytic epoxidation by hydroperoxides, which proceeds with high selectivity. From diunsaturated fatty acid esters, at least two types of peroxides with different reactivities are formed. One of them can enter into catalytic epoxidation reaction, the other forms secondary oxidation products, which are mainly represented by the products of the Baeyer–Villiger reaction. In this contribution upon using different mono- and diunsaturated fatty acid esters, the mechanism of products formation has been investigated and discussed.

Drug-release controlling nanoparticles with field-dependent spin-correlated radical pair system

The use of magnetic field effects on spin-correlated radical pair mechanisms is a new approach for applications to liposomal drug-release technologies. We prepared various types of liposomal nanoparticles from seven kinds of phospholipids, and carried out research into the drug-release potentials of the nanoparticles equipped with possible magnetic controls. Exposures to static magnetic fields were performed using a permanent magnet (0.25 T) or an air-cored coil system (60 mT). Photoirradiations of flutamide-containing liposomal nanoparticles were carried out using an original air-cooled UV-LED irradiation system. Under exposure to the static field, flutamide in the liposomal membrane was excited by an emission wavelength of 325 nm. Soon after the excitation was achieved, the spectral changes with absorbance at 314, 260, and 370 nm were measured continuously. Moreover, we investigated the magnetic field effects on the permeability of the model membrane systems, using a 31P NMR technique. According to our overall results, differences in the field dependence can be surely explained by the formation of a singlet radical pair-deriving cage product, which might have an additional steric hindering factor in the liposomal bilayer structure. The experimental result is discussed in terms of the number of unsaturated double bonds in phospholipids of liposomal membranes. Our liposomal system with reaction field-dependent radical pair mechanisms is a promising new area of research.

Elimination of Unreacted Acrylate Double Bonds in the Polymer Networks of Microparticles Synthesized via Flow Lithography.

Flow lithography (FL), a versatile technique used to synthesize anisotropic multifunctional microparticles, has attracted substantial interest, given that the resulting particles with complex geometries and multilayered biochemical functionalities can be used in a wide variety of applications. However, after this process, there are double bonds remaining from the cross-linkable groups of monomers. The unreacted cross-linkable groups can affect the particles' biochemical properties. Here, we verify that the microparticles produced by FL contain a significant number of unreacted acrylate double bonds (UADBs), which could cause irreversible biochemical changes in the particle and pernicious effects to biological systems. We also confirm that the particles contain a considerable number of UADBs, regardless of the various synthetic (lithographic) conditions that can be used in a typical FL process. We present an effective way to eliminate a substantial amount of UADBs after synthesis by linking biochemically inert poly(ethylene glycol) based on click chemistry. We verify that eliminating UADBs by using this click chemistry approach can efficiently resolve problems, such as the occurrence of random reactions and the cytotoxicity of UADBs.

Polyunsaturated Fatty Acid Regulation of the Acid-Sensing Ion Channels

The Acid Sensing Ion Channels (ASICS) are proton activated, voltage-insensitive, sodium channels found throughout the peripheral and central nervous systems. Tissue acidosis can occur due to injury, ischemia, and inflammation which can lead to ASIC activation. Pain that occurs with several of these conditions, including ischemia and inflammation, has previously been linked to the activation of ASICs. In addition, ASICs have been shown to be able to sense several pro-inflammatory agents that are increased under these pathophysiological conditions. The polyunsaturated fatty acid (PUFA), Arachidonic Acid, is one such molecule that potentiates ASIC isoforms 1a, 2 and 3 at concentrations reached during inflammation. Interestingly, several other PUFAs have been shown to similarly potentiate ASIC1a. However, no study has yet to elucidate the mechanism of PUFA potentiation, nor has there been a thorough investigation of the how different properties of PUFAs modulate their effect on ASICs. Here we characterized how PUFA chain length, number of double bonds, location of double bonds and head group relate to potentiation of several ASIC isoforms. First, we demonstrate that PUFAs potentiates ASICs via an alkaline shift in the pH dependence of activation. In contrast to a previous finding, we show that the head group is critical for ASIC regulation by PUFAs. PUFAs with a negatively charged head group, like Arachidonoyl Glycine, dramatically shift the pH dependence of ASIC activation while uncharged head groups like Arachidonic Acid methyl ester have no effect on channel function. In addition, we show that the position of double bonds in the fatty acid tail are important for ASIC regulation as well. Finally, mutagenesis is used to localize possible PUFA interaction sites with ASICs.

Low-Level Fusion of Fourier Transform Ion Cyclotron Resonance Mass Spectrometry Data Sets for the Characterization of Nitrogen and Sulfur Compounds in Vacuum Gas Oils.

A total of 18 vacuum gas oils have been analyzed by Fourier transform ion cyclotron resonance mass spectrometry considering six replicates in three different ionization modes (electrospray ionization (ESI)(+), ESI(-), and atmospheric pressure photoionization (APPI)(+)) to characterize the nitrogen and sulfur compounds contained in these samples. Classical data analysis has been first performed on generated data sets using double bond equivalents (DBE) versus number of carbon atoms (#C) plots in order to observe similarities and differences within the nitrogen and sulfur-containing molecular classes from samples produced by different industrial processes. In a second step, three-way arrays have been generated for each ionization mode considering three dimensions: DBE related to aromaticity, number of carbon atoms related to alkylation, and sample. These three-way arrays have then be concatenated using low-level data fusion strategy to obtain a new tensor with three new modes: aromaticity, alkylation, and sample. The PARAFAC method has then been applied for the first time to this three-way data structure. A two components decomposition has allowed us to highlight unique samples with unexpected reactivity behaviors throughout hydrotreatment. The obtained loadings led to the identification of the variables responsible for this specific character. This original strategy has provided a fast visualization tool able to highlight simultaneously the impact of the three ionization modes in order to explain the differences between the samples and compare them.

Relationship Between the Gastrointestinal Side Effects of an Anti-Hypertensive Medication and Changes in the Serum Lipid Metabolome

An earlier study using a rat model system indicated that the active ingredients contained in the anti-hypertensive medication amlodipine (AMD) appeared to induce various bowel problems, including constipation and inflammation. A probiotic blend was found to alleviate intestinal complications caused by the medicine. To gain more extensive insight into the beneficial effects of the probiotic blend, we investigated the changes in metabolite levels using a non-targeted metabolic approach with ultra-performance liquid chromatography-quadrupole/time-of-fligh (UPLC-q/TOF) mass spectrometry. Analysis of lipid metabolites revealed that rats that received AMD had a different metabolome profile compared with control rats and rats that received AMD plus the probiotic blend. In the AMD-administered group, serum levels of phosphatidylcholines, lysophosphatidylcholines, sphingomyelins, triglycerides with large numbers of double bonds, cholesterols, sterol derivatives, and cholesterol esters (all p < 0.05) were increased compared with those of the control group and the group that received AMD plus the probiotic blend. The AMD-administered group also exhibited significantly decreased levels of triglycerides with small numbers of double bonds (all p < 0.05). These results support our hypothesis that AMD-induced compositional changes in the gut microbiota are a causal factor in inflammation.

Characterization of pharmaceutic structured triacylglycerols by high-performance liquid chromatography/tandem high-resolution mass spectrometry and its application to structured fat emulsion injection.

Structured triacylglycerols (STAGs) are a complex mixture of triacylglycerols which are esterified by long-chain fatty acids and medium-chain fatty acids with the same glycerol molecular backbone. As a kind of lipid pharmaceutic excipients, STAGs are used in the pharmaceutical industry as major components of structured fat emulsion injections and play an important role in pharmaceutic energy material because they improve nutritional status with faster elimination in a safe way. The composition and proportion of triacylglycerols in STAGs are closely related to the stability of pharmaceutical preparations and curative effects in the clinic. Therefore, it is necessary to characterize pharmaceutic STAGs using a rapid and accurate method. An analytical method for rapid and accurate determination of triacylglycerols in pharmaceutic STAGs was developed using high-performance liquid chromatography/tandem high-resolution mass spectrometry (HPLC/HRMS). Triacylglycerol components could be well separated on a Waters Xterra MS C8 (2.1 × 100 mm, 3.5 μm) column. Four-dimensional HPLC/HRMS data (high-resolution m/z, MS2 data, retention time and isotopic intensity distribution) were used to identify triacylglycerols using Lipid Data Analyzer (LDA) software and the LIPID MAPS database. Then, these identified triacylglycerol components were relatively quantified by their corresponding normalized peak areas using representative standard curves of structurally similar standard substances. Forty-seven kinds of triacylglycerol components in pharmaceutic STAGs and structured fat emulsion injection were identified and relatively quantified by this method. It has been shown that their retention times are in good correlation with the number of carbon atoms and carbon-carbon double bonds. The main components in pharmaceutic STAGs and structured fat emulsion injection were triacylglycerols containing both medium-chain fatty acids and long-chain fatty acids, while the other components, including triacylglycerols containing three medium-chain fatty acids and triacylglycerols containing three long-chain fatty acids, were relatively low. This study has provided a rapid and accurate approach for the identification and quality control of pharmaceutic STAGs and structured fat emulsion injection and this approach can be extended to other lipid pharmaceutic excipients and used as an effective and reasonable control to guarantee the quality of pharmaceutical preparations.

The long-chain alkenones in the upper layers of bottom sediments of salt lakes in Southern Siberia as a potential biomarker of paleo-climate

The long-chain alkenones in the upper layers of the bottom sediments of ten salt lakes in Southern Siberia were collected as a bio-marker for paleo-limnological studies in the summer 2019. The quantitative and qualitative composition of long-chain alkenones were determined by means of gas chromatography mass spectrometry. Also, the possibility of using this class of compounds as a salt-sensitive bio-marker for paleoclimatic reconstructions in the corresponding regions was assess. The results showed that the extracted alkenones are a mixture of several fractions with different lengths of the carbon chain and the number of double bonds. The alkenone C37:4 fractions positively correlate with the salinity of the studied lakes and can serve as a marker of salinity in paleo-climatic reconstructions.

The fingerprint of essential bio-oils by Fourier transform ion cyclotron resonance mass spectrometry.

Six essential oils were analyzed by Fourier transform ion cyclotron resonance mass spectrometry coupled to negative-ion electrospray ionization (ESI(-)/FT-ICR MS). ESI offers selective ionization of a compound's polar functional groups containing nitrogen and oxygen heteroatoms. ESI in negative-ion mode allows the identification of the acidic compounds. The results showed that the samples contain between 1100-3600 individual molecular compositions, which corresponds to the greatest number of species detected to date in essential oils obtained from aromatic plant material. The compositions cover a mass range between m/z 150-500 with up to 41 carbon atoms. The dominant organic constituents of the essential oils correspond to species incorporating 2-5 oxygen atoms, detected as deprotonated/sodiated/chlorinated species. A set of 580 molecular assignments were found in common across all the samples and for the first time, a set of unique molecular systems were identified, and up to 1373 species as a unique composition for each essential oil. The molecular distributions plotted in van Krevelen diagrams (classified by their H/C vs. O/C values) suggest the presence of species with long alkyl chains and low numbers of rings plus double bonds.

Modifications of Membrane Phospholipids in Response to Extended Aging from Pork Loins

ObjectivesIt is well established that fresh meat shelf-life deteriorates during aging process. We hypothesize that part of the shelf-life reduction is due to membrane phospholipid deterioration through phospholipase activity and/or phospholipid oxidation during aging. Therefore, the objective of this study was to characterize the modifications/deterioration of phospholipid classes/species in pork loins from 3 different aging periods.Materials and MethodsLoins from 20 carcasses were collected at a commercial harvest facility in the Midwest 1 d postmortem from carcasses of Duroc sired crossbred pigs. Four chops from each carcass containing only the longissimus muscle were vacuum packaged and aged at 4°C for 1, 8, and 21 d. A sensitive approach based on electrospray ionization tandem mass spectrometry was used to comprehensively analyze phospholipid composition using the lipid extract from each sample at each aging period (n = 60). Unsaturation index (UI; measurement of the number of double bonds) for each phospholipid species class was also calculated to quantify fatty acyl chain unsaturation for each sample in each aging period.ResultsTotal phospholipid quantity in pork loins was not different between 1d and 8d aged chops but decreased significantly from 8d to 21d of aging (806.6 vs. 297.5 nmol phospholipid/mg lipid; P &lt; 0.01). On the other hand, the mol% data (distribution of each phospholipid species in relative % of total phospholipid) revealed that phosphatidylinositol (PI) and phosphatidylserine (PS) increased in mol% from 1d to 21d of aging in pork loins (P &lt; 0.01). This increase was mainly due to the increase of PI 38:4 (primarily 18:0/20:4) and PS 36:2 (primarily 18:0/18:2) between 1d and 21d samples (P &lt; 0.01). The results showed that phospholipid degradation products like lysophosphatidylcholine (LPC) mol% rose quickly after short term aging (8d) but remained constant through the rest of the 21d aging period (P &lt; 0.01). Conversely, lysophosphatidylethanolamine (LPE) was unaltered between 1d and 8d of aging but decreased between 8d and 21d aged pork loins (P &lt; 0.01). The mol% of phosphatidic acid (PA) also increased between 1d and 21d aged pork loins (P &lt; 0.05). Extended aging did not alter the mol% of total phosphatidylcholine (PC), ether-linked PC (ePC), sphingomyelin (SM), phosphatidylethanolamine (PE) or ether-linked PE (ePE; P &gt; 0.05). Surprisingly, UI revealed the exact opposite trend as the mol% data. The UI of PI and PS decreased (P &lt; 0.01) from 1d to 21 d of aging in pork loins due to the disappearance of many minor PI and PS species with very long chain fatty acids and multiple double bonds such as PI 42:10 and PS 44:10. There was also a slight increase of PC UI after 8 d of aging in pork loins (P &lt; 0.01). The UI for LPC, ePC, SM, LPE, PE, ePE and total phospholipid were not altered in any of the aging periods (P &gt; 0.05).ConclusionThese results confirmed our hypothesis that phospholipids undergo extensive degradation during aging. The data also indicated that the majority of phospholipids in pork loins may maintain integrity over short period aging (1–8d). Among the phospholipid classes, PI and PS were slightly more resistant to deterioration compared with the others due to their ability to modify fatty acyl chain saturation. Additional investigations are necessary to define the role of phospholipid modifications in fresh pork shelf-life and flavor.

Unsaturation‐Dependent Nanostructures Self‐Assembled from Oligopeptide Amphiphiles Capable of Generating Singlet Oxygen

AbstractWe report here on three oligopeptide amphiphiles (OPA1‐3) with different unsaturated double bonds, which self‐assemble into shape‐specific nanostructures. It was found that OPA1 with saturated hydrophobic tail self‐assembled into conventional cylindrical nanofibers, while the unsaturated OPA2‐3 molecules self‐organized into helical nanoarchitectures. Due to the different double bond numbers in hydrophobic tails of OPA2‐3, the helical pitch and width of their self‐assemblies varied. Specially, linoleic acid‐bearing OPA3 could be oxidized by lipoxidase to create hydroperoxide‐containing OPA4, which further generated singlet oxygen (1O2) in the presence of catalytic iron (II) ion. The established system may provide a self‐deliverable nanoplatform for 1O2‐mediated cancer treatment.

Predicting the soot emission tendency of real fuels – A relative assessment based on an empirical formula

Significant progress is going on in the development of non-fossil based alternative fuels which are designed to be sustainable, have potential to substitute (fully or partially) the fossil-based fuels and importantly are targeted to reduce emissions. Though soot emission characteristics has not been focus of fuel certification process yet, due to growing environmental concerns it is important to consider this aspect in the fuel design and understand its emission patterns.It is known that soot formation in combustion is linked to the degree of branching, degree of unsaturation or the degree of cyclization of a fuel molecule. This information is used to extract soot emission properties of complex real fuel mixtures. To do so, we use the definition of hydrogen deficiency (HD) which gives information on the number of double bonds or cyclic structures present in a fuel. With the help of one measured emission property, the same property of different fuels is predicted using HD. This way, we obtain a relative assessment of fuels’ sooting tendency compared to other known fuels. In this work, soot emission pattern of six jet fuels (reference fuels and synthetic fuels) is predicted based on HD and compared them with the recent ground-test measurements of V2527-A5 engine of an Airbus A320. In addition, two more test cases are provided: aviation fuels and diesel fuels, to predict sooting tendency using HD to support our concept. The prediction of the sooting propensity based on HD was found in excellent agreement with the measurements.

Maternal diet, rather than obesity itself, has a main influence on milk triacylglycerol profile in dietary obese rats

Triacylglycerols (TG) in milk derive from different sources, and their composition may be influenced by both maternal diet and obesity. We used two rat models to ascertain potential changes in TG composition in milk associated to maternal intake of an obesogenic diet during lactation and to distinguish them from the effects attributable to maternal adiposity. Milk samples were obtained from dams fed a cafeteria diet during lactation (CAF) and from dams made obese by cafeteria diet feeding, with dietary normalization before gestation (PCaf). Levels of specific TG species in milk collected at different time points of lactation were determined by shotgun lipidomics. CAF and PCaf dams presented a greater adiposity than their respective controls. The principal component analysis of TG peaks showed a clear separation between milk from CAF dams and milk from control and Pcaf dams, already evident at 5 days of lactation. Milk from CAF dams was enriched with TG species with greater number of carbons and double bonds and reduced in TG with lower number of carbons. TG composition of milk from Pcaf dams was similar to controls, although specific differences were observed at day 5 of lactation. Thus, the intake of a cafeteria diet during lactation, rather than maternal adiposity, alters milk composition. This effect is avoided with dietary normalization before gestation, although the remaining fat reserves may also influence TG composition at initial stages of lactation. Therefore, normalization of maternal diet prior to pregnancy should be considered as a strategy for achieving optimal milk composition.

Inverse vulcanized sulfur–cycloalkene copolymers: Effect of ring size and unsaturation on thermal properties

Herein, we study the influence of ring size and number of carbon-carbon double bonds of cycloalkene on structure property relation of inverse vulcanized sulfur copolymers. Reaction kinetics was monitored by XRD and the copolymer structure was confirmed by 1H NMR and FTIR spectroscopy. DSC and TGA indicate the significant increase in Tg and thermal stability of the copolymer with increase in ring size and number of double bonds density; respectively. Thermal conductivity of the copolymers (0.083 W/mK at 50 °C) was also considerably reduced compared to the pristine sulfur, which make these copolymer suitable for thermal insulation applications. Moreover, these sulfur-rich copolymers can also be used as potential cathode materials in lithium-sulfur batteries.

Regiospecific Analysis of Triacylglycerols by Ultrahigh-Performance-Liquid Chromatography-Electrospray Ionization-Tandem Mass Spectrometry.

An ultrahigh-performance-liquid chromatography-electrospray ionization-tandem mass spectrometry (UHPLC-ESI-MS/MS) method was developed for the analysis of AAB and ABC type triacylglycerol (TG) regioisomers. Excellent linear regressions were established between the ratio of [RR]+ product ions and the proportion of regioisomers of TGs. The method was further optimized by analysis of 18 regiospecific pairs of AAB type TGs and five triplets of regioisomers of ABC type TGs with acyl carbon number (ACN) ranging from 36 to 54 and the number of double bonds (DB) from 0 to 7. Reverse linear relationships were recognized between the slope of the calibration curve and the number of double bonds of the sn-2 fatty acids. Negative linear regressions were found between the intercepts of the calibration curves and the sum of ACN + DB of sn-2 fatty acids. The method was highly repeatable as shown by the low deviation and high stability of the calibration curves at different concentrations and between different periods of analysis. This is the first time that calibration curves for the ABC type TGs are reported. The results provide crucial and novel information for reliable and quantitative determination of regioisomeric TGs in natural fats and oils.

Preparation of dye sensitized solar cell (DSSC) using isolated anthocyanin fromfruit sat (melastomamalabathricum l) dicopimented with salicylic acid as dye

A study has been conducted on the use of anthocyanin extract from fruits (Melastomamalabthricum L), which was incubated by the addition of salicylic acid as photosensitizer in DSSC solar cells. The objective of this study was to determine the optimum condition of the extracts of copigmenation which resulted in the optimum efficiency of DSSC solar cells by increasing the absorption ability of anthocyanin pigment photons.The method used is the method of copigmentation. Copigmentation is an anthocyanin reaction with a copigment compound to form a more complex anthocyanin structure with a number of double bonds that can absorb more photons than the original anthocyanin.. The results of dye characterization using UV-Vis and FTIR indicate a wider absorption spectrum and a more complex structure in antigianated anthocyanins when compared without copigmentation. Based on the results of the characterization of the prepared TiO2 thin film, obtained crystal size of TiO2 used ranged from 27.377 to 64.738 nm with a width of200-950 nm photocathode spekrum absorption. Based on the results of the research, it is found that the antiganant extract can be increased by DSSC solar cell efficiency from 0.62% to 1.32% with 24 hours of copigmentation time and 1: 2 concentration of concentration.

Characterization of bio-crude components derived from pyrolysis of soft wood and its esterified product by ultrahigh resolution mass spectrometry and spectroscopic techniques

In this work, a detailed analysis of a bio-oil obtained by pyrolysis of softwoods and its esterified product is described. Information of the type of chemical function groups were obtained by 13C and 1H nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FT-IR) and compositional analysis was obtained by Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS). The results obtained indicate that aliphatic hydrogen and carbon atoms are found in higher abundance, compared with aromatic hydrogen-carbon frameworks. Furthermore, a decrease in oxygen functional groups was observed after esterification. According to the FTICR MS results, the samples contain highly oxygenated species corresponding to compound classes Ox, NOx and BOx, with a high predominance of Ox species. After esterification, the compositions shifted towards lower oxygen-content, lower number of rings and double bonds, and longer alkyl chains as a consequence of the water removal via the condensation reaction.

Modeling systems relevant to the biodiesel production using the CPA equation of state. Part 2. Systems with supercritical CO2

The CPA EoS is applied to binary mixtures of CO2 with fatty acids and their methyl- or ethyl-esters. The model, using one temperature independent binary interaction parameter, satisfactorily describes the phase behavior of such systems. Correlations of the binary interaction parameters with the number of esters' or acids’ carbon atoms, or with the number of double bonds for compounds with the same number of carbon atoms, were developed in order to make predictions feasible in cases of lack of experimental data. Subsequently, the model was applied for predicting the phase behavior of ternary and multicomponent mixtures. The model rather satisfactorily predicts the vapor-liquid equilibrium of such systems. In accordance with the first part of this series of articles [Tsivintzelis et al. 430 (2016) 75–92], since the binary parameters were optimized solely using experimental data for binary mixtures, CPA results for the ternary and multicomponent mixtures are pure predictions.