Saturated Alkyl Chains Research Articles

Cultivation of Chlorella vulgaris in wastewater: biodiesel potential and wastewater remediation.

The present investigation has evaluated the use of effluents from a secondary municipal wastewater treatment plant for biomass production and potential of the biomass for biodiesel production. Cultivations of Chlorella vulgaris using wastewater, wastewater with supplementation, and WC medium were carried out. Effect of wastewater collected in different months on biomass productivity (BP) and lipid composition was studied. Methods based on NMR and GC-MS techniques were applied for determining the composition of the lipids and their fatty acid profile including poly unsaturated fatty acids (PUFAs). Lipids extracted are comprised of both neutral (tri acyl glycerides, TAG; free fatty acids, FFA) and polar (glyco glycero/phospho) lipids. The TAG content of the extracted lipids was determined in the range of 22.5-41.3% w/w. The NMR and GC-MS compositional results of microalgal lipids of biomasses cultivated in wastewater without nutrient supplementation, collected in different months, showed potential for biodiesel production. The fatty acid profiles of neutral and polar lipids, which are mainly comprised of saturated and unsaturated long alkyl chain (C16-C22) fatty acids, are potential sources for the biodiesel and food industry. The concentration of nitrates (45-78mg L-1) in wastewater without supplementation, collected in different months, was found to be optimum to enable cultivation of biomasses with reasonably good BP of 21.5-28.1mg L-1day-1. Similar results have been obtained in the present work as well as reported in the literature in the case of WC medium (nitrate, 69mg L-1) with BP of 25.5-28.2mg L-1day-1, thus highlighted the significance of the presented work.

Surface miscibility of Gemini surfactants and DOPE in binary mixed monolayers

AbstractSurface pressure (π)–molecular area (A) isotherms were gathered to characterize the packing of binary mixed Langmuir monolayers of 1,2‐dioleoyl‐sn‐glycero‐3‐phosphoethanolamine (DOPE) and one of two Gemini surfactants (GS), N,N‐bis(dimethyloctadecyl)‐1,7‐nonanediammonium dibromide (18‐7‐18) or 1,9‐bis(octadecyl)‐1,1,9,9‐tetramethyl‐5‐amino‐1,9‐nonanediammonium dibromide (18‐7NH‐18) of varying molar fractions. Information about miscibility behavior was derived from the π–A curves by examining the excess free energy of mixing (ΔGexc) that was calculated through the surface area additivity rule. Surface compressibility modulus (Cs−1) was also used to characterize intermolecular interactions. Mutual interactions between GS and DOPE were analyzed in terms of excess Gibbs energy of mixing and the value of this parameter depended strongly on the composition of the mixed film. GS and DOPE are generally miscible as DOPE reduces intermolecular repulsion between highly charged GS molecules leading to the formation of more densely packed mixed monolayers. However, GS and DOPE are immiscible in equimolar mixtures due to tail group packing mismatch between saturated and unsaturated alkyl chains. The prevalence of attractive synergistic interactions in the monolayers studied differs from a previous finding of antagonistic mixing behavior in GS/DOPE micelles. These results contribute to the understanding of GS‐lipid interactions and packing that are critical to the in vitro and in vivo stability of liposomes composed of these molecules used for non‐viral gene therapy applications.

Controlling supramolecular copolymerization of alkynylplatinum(ii) terpyridine complexes: from isodesmic to cooperative mechanisms.

Recently, cooperative supramolecular polymerization has garnered considerable attention due to its significant potential for enabling controlled chain-growth polymerization, which offers a route to achieving a well-defined degree of polymerization and low polydispersity. In this study, we synthesized two distinct alkynylplatinum(ii) complexes, one bearing a saturated long alkyl chain (Pt-Sat-C18) and another containing a diacetylene moiety within a long alkyl chain (Pt-DA-C25). Spectroscopic analyses revealed that Pt-Sat-C18 undergoes supramolecular polymerization via an isodesmic pathway, while Pt-DA-C25 assembles cooperatively. Intriguingly, the mechanism of supramolecular copolymerization could be tuned by varying the composition ratios: transitioning from an isodesmic to a cooperative pathway was achieved by increasing the proportion of Pt-DA-C25. Moreover, UV irradiation prompted a shift from an isodesmic to a cooperative assembly mechanism. Morphologically, self-assembled Pt-Sat-C18 resulted in left-handed fibrillar structures, whereas Pt-DA-C25 led to left-handed tubular assemblies. Supramolecular co-assembly further revealed helical ribbon or tubular structures. Photoluminescent properties were also observed, with emission spectra centered at approximately 650 nm, attributed to the formation of excimer species facilitated by strong Pt⋯Pt interactions. To elucidate the mechanisms underlying these supramolecular polymerizations, temperature-dependent UV-visible spectroscopy was conducted during the cooling/heating processes, and thermodynamic parameters for both isodesmic and cooperative pathways were quantitatively assessed through curve fitting.

Geometrical and positional isomers of unsaturated furan fatty acids in food.

Furan fatty acids (FuFA) are important antioxidants found in low concentrations in many types of food. In addition to conventional FuFA which normally feature saturated carboxyalkyl and alkyl chains, a few previous studies indicated the FuFA co-occurrence of low shares of unsaturated furan fatty acids (uFuFA). For their detailed analysis, the potential uFuFA were enriched by centrifugal partition chromatography (CPC) or countercurrent chromatography (CCC) followed by silver ion chromatography from a 4,7,10,13,16,19-docosahexaenoic acid ethyl ester oil, a 5,8,11,14,17-eicosapentaenoic acid ethyl ester oil and a latex glove extract. Subsequent gas chromatography with mass spectrometry (GC/MS) analysis enabled the detection of 16 individual uFuFA isomers with a double bond in conjugation with the central furan moiety. In either case, four instead of two uFuFA isomers previously reported in food, respectively, were detected by GC/MS. These isomers showed characteristic elution and abundance patterns in GC/MS chromatograms which indicated the presence of two pairs of cis/trans-isomers (geometrical isomers).

Exploratory study of oxatomide derivatives with high P2X7 receptor inhibitory activity

Various oxatomide derivatives were designed and synthesized to develop novel P2X7 receptor (P2X7R) antagonists. Evaluation for in-vitro P2X7R antagonist assay showed that DPM-piperazine moiety of oxatomide was required to maintain an inhibitory activity. The structure of both alkyl chains and aromatic head groups strongly affected P2X7R inhibitory activity, and the analogue, with C4-type saturated alkyl chain and a non-substituted or fluorine-substituted indole, was 7.3 to 6.4 times more potent as a P2X7R antagonist than oxatomide.

Biofuels energetics: Reconciliation of calorific values of fatty acids methyl esters with help of complementary measurements and structure–property relationships

The fatty acids methyl esters with the saturated and unsaturated alkyl chains are known as a renewable alternative fuel – biodiesel. Calorific values were measured using high-precision combustion calorimetry. Heat capacities were measured using differential scanning calorimetry. Vaporisation enthalpies were measured using thermogravimetric analysis. The thermodynamic properties of fatty acid methyl esters available in the literature were collected, combined with our own new results and validated using structure–property relationships and quantum chemical calculations. The sets of evaluated thermodynamic properties have been recommended for chemical-engineering calculations. The group additivity contributions to the prediction of vaporisation and formation enthalpies of esters relevant to biodiesel production were developed and tested.

Biofuels energetics: Measurements and evaluation of calorific values of triglycerides

The triglycerides with the saturated alkyl chains containing 3, 4, and 6 carbon atoms, as renewable energy sources were investigated. Specific energies of combustion were measured by using high-precision combustion calorimetry. The standard molar enthalpies of combustion and formation were derived from these results. Validation of the new calorific data for triglycerides was performed using the structure-property relationships. The experimental and additive enthalpies of formation for triglycerides measured in this work agree well and could be recommended for the thermochemical calculations for triglyceride technologies.

Subgel-phase formation of membranes of ether-linked phosphatidylcholines

The formation of subgel (so-called hydrated crystal) phase of membranes of ether-linked phospholipids, dialkylphosphatidylcholines containing linear saturated alkyl chain (Cn = 14, 16 and 18), was examined under atmospheric and high pressure. The results of differential scanning calorimetry in 50 wt% aqueous ethylene glycol solution and water showed that these PC membranes undergo the subtransition from the subgel phase to the gel phase at a low temperature with or without the thermal pretreatment of lipid samples called annealing. The subtransition in water was clearly observed by light-transmittance measurements under high pressure and the transition temperature increased by applying pressure. The temperature-pressure phase diagrams and the thermodynamic quantities of the subtransition were obtained from the phase-transition data and compared with those of membranes of ester-linked phospholipids, diacylphosphatidylcholines. The phase diagrams indicated that all gel phases of the ether-linked PC membranes exist as stable phases while parts of the gel phases of the ester-linked PC membranes are metastable. The subtransition temperatures of the ether-linked PC membranes were lower than those of the ester-linked PC membranes by more than 10 °C and the corresponding thermodynamic quantities were extremely small. Further, it was revealed by high-pressure fluorometry that the difference in subgel phase between ether- and ester-linked PC membranes results from their phase structures: the nonbilayer interdigitated structure is maintained after the conversion from the gel phase to the subgel phase in the ether-linked PC membranes whereas the ester-linked PC membranes form the bilayer subgel phase with staggered structure.

Design Principles of Lipid-like Ionic Liquids for Gene Delivery

We developed lipid-like ionic liquids, containing 2-mercaptoimidazolium and 2-mercaptothiazolinium headgroups tethered to two long saturated alkyl chains, as carriers for in vitro delivery of plasmid HEK DNA into 293T cells. We employed a combination of modular design, synthesis, X-ray analysis, and computational modeling to rationalize the self-assembly and desired physicochemical and biological properties. The results suggest that thioamide-derived ionic liquids may serve as a modular platform for lipid-mediated gene delivery. This work represents a step toward understanding the structure-function relationships of these amphiphiles with long-range ordering and offering insight into design principles for synthetic vectors based on self-assembly behavior.

Optimization of invert emulsion oil-based drilling fluids performance through heterocyclic imidazoline-based emulsifiers

In this work six structurally related imidazoline oligomers based on the reaction of liner polyamine with saturated and unsaturated long alkyl chains (C18 oleic and stearic) fatty acids were prepared, followed by a quaternization reaction to produce new conventional and gemini imidazolinium quaternary salts. The chemical structures of prepared amphiphiles were confirmed via spectroscopic methods and elemental microanalysis, also, the prepared emulsifier’s characterization has been studied through static interfacial tension, visual and microscopic examination of prepared emulsification systems. The static interfacial tension measurements show a high ability to reduce interfacial tension values between diesel oil and water. The visual and microscopic examination gave evidence of a multilayer interface around emulsion particles and an increase of emulsion droplets size as a function of time with acceptable emulsion stability and phase separation. For both oil-based mud cost and diesel oil toxicity, this article brings to light many important aspects of designing new emulsifiers for low toxicity invert emulsion muds with lower diesel oil content. The prepared emulsifiers were mixed to be investigated and evaluated as primary emulsifiers package to formulate the invert emulsion oil-based muds (IEOBMs). The electrical stability, rheological properties, and filter loss were evaluated before and after hot roller aging and compared with the reference mud sample formulated from the commercial-grade emulsifiers. The experimental investigations conducted based on the Herschel-Bulkley rheological model showed good rheological behavior compared to the reference mud sample, high resistance to the deformation that occurred to prepared mud systems due to hot roller aging, good electrical stability, and high pressure-high temperature filtration loss values.

Tuning G-Quadruplex Nanostructures with Lipids. Towards Designing Hybrid Scaffolds for Oligonucleotide Delivery

Two G-quadruplex forming oligonucleotides [d(TG4T)4 and d(TG6T)4] were selected as two tetramolecular quadruplex nanostructures because of their demonstrated ability to be modified with hydrophobic molecules. This allowed us to synthesize two series of G-quadruplex conjugates that differed in the number of G-tetrads, as well as in the terminal position of the lipid modification. Both solution and solid-phase syntheses were carried out to yield the corresponding lipid oligonucleotide conjugates modified at their 3′- and 5′-termini, respectively. Biophysical studies confirmed that the presence of saturated alkyl chains with different lengths did not affect the G-quadruplex integrity, but increased the stability. Next, the G-quadruplex domain was added to an 18-mer antisense oligonucleotide. Gene silencing studies confirmed the ability of such G-rich oligonucleotides to facilitate the inhibition of target Renilla luciferase without showing signs of toxicity in tumor cell lines.

Cationic amphiphiles based on malonic acid amides as transfection mediators

Objectives. The aim of this work is to synthesize cationic amphiphiles based on malonic acid amides. The target compounds should contain saturated and unsaturated alkyl chains in the hydrophobic portion, and one or two positive charges in the polar head as created by ethylenediamine and amino acid L-ornithine. For such cationic amphiphiles, we determined physicochemical properties and transfection efficiency of liposomes based on them.Methods. The initial compound in the synthesis is diethylmalonate. We used C-alkylation to add the first hydrophobic chain (with octylbromide, dodecylbromide, or octadecylbromide). N-oleylamine was used as the second hydrophobic chain, which was attached at the carboxyl group of the malonic acid via amide bond formation. The polar head was represented by ethylenediamine, which was then attached at the second carboxyl group of the malonic acid. Further, L-ornithine was attached to ethylenediamine to produce cationic lipids with two positive charges in the head group. The structures of the compounds were characterized by infrared spectroscopy, nuclear magnetic resonance spectroscopy, and elemental analysis. Particle size distribution was evaluated by photon correlation spectroscopy. The luciferase test was used to determine transfection efficiency using HeLa cells.Results. We have developed a synthesis scheme to produce new cationic amphiphiles with an asymmetric hydrophobic part. The obtained liposomal particles are approximately 120 nm in size and have a relatively high zeta potential of 29–30 mV.Conclusions. The size of these liposomes allows them to penetrate into cells, which makes it possible to use these compositions for transfection. The high zeta potential shows that the particles are stable. Our results demonstrate that the transfection efficiency of our liposomes (mixed with cholesterol) is comparable to a commercial formulation. Cationic amphiphiles based on malonic acid amides have great potential for liposome development for transfection.

Effects of unsaturated double bonds on adsorption and aggregation behaviors of amide-based cationic Gemini surfactants

Four cationic amide Gemini surfactants, containing unsaturated and saturated hydrophobic chains, were synthesized from oleamide propyl dimethylamine (PKO-18:1) and stearate amide propyl dimethylamine(PKO-18). The chemical structures of the synthesized compounds were characterized by FT-IR spectra and 1H NMR. The Krafft temperatures were experimentally determined.. Their critical micelle concentration(CMC) in the aqueous solutions were determined by surface tension and conductivity methods. Equilibrium surface tension parameters such as γcmc, pC20, Гmax, Amin, △G°mic(Gibbs free energy of micellization), △G°ads(Gibbs free energy of adsorption) were obtained. Their adsorption behavior was analyzed through dynamic surface tension. Also, their self-assembly behaviors were investigated by negative-stained transmission electron microscopy(TEM) and critical packing parameter calculation. The results showed that the unsaturated double bond in hydrophobic chains was favorable for lowering the Krafft temperature and CMC. The oleamide-based Gemini surfactants present a lower Krafft temperature, higher surface activity and the adsorption kinetic process were conformed mixed diffusion-kinetic control model. The TEM results showed that the oleamide-based Gemini surfactants containing unsaturated double bonds in hydrophobic chains preferentially form worm-like micelles in solution. However, the stearate amide Gemini surfactants whose hydrophobic chains are saturated alkyl chains tend to form spherical aggregates in solution.

High-speed single-molecule imaging reveals signal transduction by induced transbilayer raft phases.

Using single-molecule imaging with enhanced time resolutions down to 5 ms, we found that CD59 cluster rafts and GM1 cluster rafts were stably induced in the outer leaflet of the plasma membrane (PM), which triggered the activation of Lyn, H-Ras, and ERK and continually recruited Lyn and H-Ras right beneath them in the inner leaflet with dwell lifetimes <0.1 s. The detection was possible due to the enhanced time resolutions employed here. The recruitment depended on the PM cholesterol and saturated alkyl chains of Lyn and H-Ras, whereas it was blocked by the nonraftophilic transmembrane protein moiety and unsaturated alkyl chains linked to the inner-leaflet molecules. Because GM1 cluster rafts recruited Lyn and H-Ras as efficiently as CD59 cluster rafts, and because the protein moieties of Lyn and H-Ras were not required for the recruitment, we conclude that the transbilayer raft phases induced by the outer-leaflet stabilized rafts recruit lipid-anchored signaling molecules by lateral raft-lipid interactions and thus serve as a key signal transduction platform.

Corrosion inhibitor by a polymerizable columnar mesogen based on hexabenzocoronene derivative

AbstractA hexa‐peri‐hexabenzocoronene derivative (HBC‐1,2,4‐Ph‐DA‐C12) with the central HBC core tethered with three diacetylene (DA)‐containing chains and three saturated alkyl chains was applied for the anticorrosion of an iron surface. This compound, which exhibits a columnar liquid crystalline phase, could be polymerized by ultraviolet irradiation through reactions between the DA units. This polymer coating exhibited a good anticorrosion property with good hydrophobicity (contact angle [CA] ~ 84°–105°) and excellent mechanical property. It showed a high resistance of 149 kΩ/cm2, much higher than that of known anticorrosion materials.

Alignment and Photopolymerization of Hexa-peri-hexabenzocoronene Derivatives Carrying Diacetylenic Side Chains for Charge-Transporting Application.

Thin films of four discotic liquid-crystalline hexa-peri-hexabenzocoronene (HBC) derivatives carrying three diacetylenic side chains and three saturated alkyl chains at different positions around the central HBC core were prepared on phenyltrichlorosilane-modified SiO2 substrate by the Chinese brush-coating method. The brush-coated films of molecules with D3h symmetry and C1 symmetry all exhibited anisotropic alignment with an edge-on orientation and molecular π-π stacking along the coating direction on the surface, in contrast to the spin-coated films, where a mixture of face-on and edge-on orientations was obtained. Hexagonally packed columnar structure or lamella-like columnar structure was obtained, depending on the location of the diacetylenic unit along the chain. UV irradiation of the films resulted in cross-linking/polymerization of the molecular columns. Among them, the lamella-like structure with a diacetylene unit closer to the HBC core gave more closely packed and ordered HBC arrays with the poly(ene-yne) backbones stretching along the column direction, based on a variety of experimental evidence. A thin-film transistor based on this irradiated film gave a highest mobility of 1.5 cm2 V-1 s-1 along the column direction, which is a 3 orders of magnitude improvement over that of the monomeric film. However, for those with a diacetylenic unit extended farther away from the core, cross-linking between neighboring columns was suggested to occur and no mobility can be measured for devices based on those films.

Temperature-Responsive Molecular Assemblies Using Oligo(Ethylene Glycol)-Attached Polyamidoamine Dendron Lipids and their Functions as Drug Carriers.

Temperature-responsive nanocarrier systems using external stimuli are one of the most widely investigated stimuli-responsive strategies because heat is easy and safe to use for hyperthermia and controlled drug delivery. Polyamidoamine dendron lipids (PAMAM-DLs) composed of PAMAM dendron as head group and two alkyl chains can exhibit temperature-responsive morphological change through the attachment of suitable moieties to terminal of PAMAM dendron. In this study, oligo(ethylene glycol)s including ethoxy- or methoxy-diethylene glycols were attached to the terminals of PAMAM-DL, and temperature-responsive properties of their self-assemblies were evaluated by calorimetric and turbidity measurements. In the evaluation of temperature-responsive properties, ethoxy diethylene glycol (EDEG)-attached PAMAM-DL composed of two saturated alkyl chains and PAMAM dendron with 1st generation had lipid bilayer structure and suitable cloud point for the application as drug carrier. In vitro performances of the assemblies combining EDEG-attached PAMAM-DLs with cholesteryl-oxy-poly(ethylene glycol) (PEG-Chol) was evaluated using doxorubicin (DOX) as an anticancer drug. Cellular uptake of DOX-loaded EDEG-attached PAMAM-DL/PEG-Chol assemblies was promoted at 42 °C rather than 37 °C, resulting in an effective decrease in cell viability.

MOLECULAR FRACTIONATION WITH CONJUGATE CAPS STUDY OF THE INTERACTION OF THE ANACARDIC ACID WITH THE ACTIVE SITE OF TRYPANOSOMA CRUZI GAPDH ENZYME: A QUANTUM INVESTIGATION

Objective: The objective of this study was to use the molecular fractionation with conjugate caps (MFCC) method to elucidate the possible interaction mechanism of anacardic acid (AA) with the saturated alkyl chain (AA0) in the Trypanosoma cruzi glyceraldehyde-3-phosphate dehydrogenase (TcGAPHD) enzyme.&#x0D; Methods: Initially, the geometry optimization of the AA three-dimensional structure (with the pentadecyl chain) was performed using density functional theory (B3LYP) calculations. With the AA0 optimization data, it was possible to plot the molecular electrostatic potential (MESP) surface. Molecular docking simulation was performed using automated coupling with the AutoDock Vina program. The best-fit conformation in the docking simulation of AA0 is the binding site used for the construction of the TcGAPHD-AA0 complex. Interaction energies between the AA0 molecule and the amino acid residues of the TcGAPHD enzyme were estimated using the MFCC strategy.&#x0D; Results: To obtain more reliable quantitative information on the interaction of AA with the active site of the TcGAPHD enzyme, the fragmentation method was combined with conjugated layers (MFCC) and molecular docking. It can be observed that the AA0 molecule occupies a region near the active site of the chalepin molecule in the TcGAPHD enzyme, and the Ile13 residue has the strongest binding energy of approximately 25 kcal/mol with AA0, through a strong Van der Waals interaction.&#x0D; Conclusion: The paper presents an improved quantitative analysis approach for assessing the contribution of individual amino acids to the free energy of interaction between AA and TcGAPHD. Specifically, the paper illustrates the advantageous approach of combining molecular docking with the MFCC method.

Spontaneous Vesicle Formation of Monododecenyl Phosphonic Acid in Water.

We report the synthesis of amphiphilic dodecenyl phosphonic acid PC12 from vinylphosphonic acid, a reactive phosphonic acid intermediate. The trans-P-C=C moiety enabled PC12 to disperse well in water. Surface tension and dynamic light scattering measurements revealed that PC12 exhibited high surface activity and reduced the surface tension of water from 72.0 to 23.6 mN/m, thereby resulting in the spontaneous formation of aggregates even in a dilute aqueous solution (critical aggregation concentration (CAC) = 4.8 × 10-4 M). In contrast to modern lipids with double-tailed structures, the PC12 of simple singletailed structure spontaneously formed bilayered vesicles, without an external energy supply. Compared with the strength of hydrogen bonds formed by the long, saturated alkyl chain of dodecyl phosphonic acid (DPA), the strength of PC12 intermolecular hydrogen bonds was weaker. The melting point of PC12 was approximately 20°C lower than that of DPA. These results indicate that the trans-P-C=C moiety was considerably important for spontaneous vesicle formation in water. Preliminary modeling of the morphological transitions of the closed bilayer structures in the vesicles was then conducted, by varying the pH and adding an α-helical peptide scaffold.

Rich liquid crystal phase behavior of novel alkyl-tri(ethylene glycol)-glucoside carbohydrate surfactants

Carbohydrates are appealing non-ionic surfactant head-groups as they are naturally abundant, generally biocompatible and biodegradable, and readily functionalized. Herein, we explore the phase behavior of seven novel carbohydrate-based surfactants (CBS) containing a tri-ethylene glycol (TEG) linker between a glucose head-group and alkyl tail-group, with linear saturated (C8–18) and cis-unsaturated (C18:1) alkyl chains. At high aqueous concentrations, these glycolipid-like surfactants transition into a variety of lyotropic liquid crystalline phases following an expected concentration phase sequence: hexagonal (H1) → bicontinuous cubic (V1) → lamellar (Lα). Using polarizing light microscopy (PLM), a binary (surfactant–water) phase diagram for each surfactant was constructed across a temperature range (25–80 °C) revealing thermotropic behavior and a broadening of liquid crystal phase regions with increasing alkyl chain length. There was also a significant difference between saturated and unsaturated alkyl chains, due to the cis-unsaturated ‘statistical bend’ lowering the melting point. Small-angle X-ray scattering (SAXS) measurements were performed to characterize the liquid crystal phases, identifying highly-ordered p6m,Ia3d, and Lα crystallographic space-groups with up to 7 resolved Bragg peaks, likely due to the highly anisometric nature of the TEG-linked surfactants. The phases were shown to be more numerous and exhibited greater thermal-stability compared to well-characterized alkyl glucoside surfactants lacking an oligoethylene spacer in the literature. Finally, the characteristic dimensions of each phase were determined to enable visualization of the internal microstructures, providing insight into the impact of molecular shape and the distribution of hydro-philicity/phobicity on the formation and stability of liquid crystalline mesophases.