Substances In Aqueous Solutions Research Articles

Fabrication of Patterned Magnetic Particles in Microchannels and Their Application in Micromixers.

Due to the extremely low Reynolds number, the mixing of substances in laminar flow within microfluidic channels primarily relies on slow intermolecular diffusion, whereas various rapid reaction and detection requirements in lab-on-a-chip applications often necessitate the efficient mixing of fluids within short distances. This paper presents a magnetic pillar-shaped particle fabrication device capable of producing particles with planar shapes, which are then utilized to achieve the rapid mixing of multiple fluids within microchannels. During the particle fabrication process, a degassed PDMS chip provides self-priming capabilities, drawing in a UV-curable adhesive-containing magnetic powder and distributing it into distinct microwell structures. Subsequently, an external magnetic field is applied, and the chip is exposed to UV light, enabling the mass production of particles with specific magnetic properties through photo-curing. Without the need for external pumping, this chip-based device can fabricate hundreds of magnetic particles in less than 10 min. In contrast to most particle fabrication methods, the degassed PDMS approach enables self-priming and precise dispensing, allowing for precise control over particle shape and size. The fabricated dual-layer magnetic particles, featuring fan-shaped blades and disk-like structures, are placed within micromixing channels. By manipulating the magnetic field, the particles are driven into motion, altering the flow patterns to achieve fluid mixing. Under conditions where the Reynolds number in the chip ranges from 0.1 to 0.9, the mixing index for substances in aqueous solutions exceeds 0.9. In addition, experimental analyses of mixing efficiency for fluids with different viscosities, including 25 wt% and 50 wt% glycerol, reveal mixing indices exceeding 0.85, demonstrating the broad applicability of micromixers based on the rapid rotation of magnetic particles.

Preparation and characterization of hydrophobically-modified sodium alginate derivatives as carriers for fucoxanthin

Micelles are nano-architectured structures capable of encapsulating hydrophobic substances in aqueous solutions, thereby improving their stability, solubility, and bioavailability to control the release of bioactive compounds. In this study, the sodium alginate backbone was modified via a hydrophobic modification scheme where octyl chains were covalently attached to the alginate chains via esterification reactions. Fourier-transformed infrared spectrometry (FTIR), 1H nuclear magnetic resonance (1H NMR), X-ray diffraction (XRD), and thermal gravimetric analysis (TGA) were used to characterize the structure of the sodium alginate derivatives of varying molar mass (ALG-C8). Fluorescence spectroscopy, surface tension measurements, and dynamic light scattering (DLS) were employed to assess the self-assembly performance of ALG-C8. The three methods produced consistent results, indicating that self-assembly decreased with higher molar mass. The self-assembled ALG-C8 micelles were utilized to encapsulate fucoxanthin. The loading capacity (LC) and encapsulation efficiency (EE) were determined using UV–Vis spectrophotometry. The molar mass of ALG-C8 has a key influence on fucoxanthin loading and release behavior. The ALG-C8 molecules with the lowest molar mass produced micelles with the smallest hydration diameter, resulting in the highest LC and EE. Furthermore, the release of fucoxanthin is significantly influenced by the pH and ionic strength of the medium. ALG-C8 micellar-like aggregates exhibit resistance to low pH and high ionic strength environments, releasing encapsulated material at the target site under alkaline conditions. Therefore, synthesized ALG-C8 is a potential candidate for preparing pH-responsive self-assembled micellar-like aggregates, enabling targeted delivery and gradual release of hydrophobic functional food components.

Study on the treatment of pyrolysis products from the nitric acid pressure leach liquor of laterite

As the demand for nickel increases sharply, it is of great significance to extract valuable metals such as nickel and cobalt from lateritic nickel ore with huge reserves. Based on the nitric acid pressure leaching process (NAPL) of laterite nickel ore, a clean process of laterite nickel ore treatment is proposed. The process includes concentration and crystallization of pressure leaching solution of nitric acid, pyrolysis of mixed nitrate crystal, alkaline leaching of mixed oxides and acid leaching of alkaline leaching residue. Based on previous work, the high-pressure alkaline leaching process of pyrolysis products (mixed oxides) and atmospheric pressure sulfuric acid leaching process of alkaline leaching residue were studied in this paper. First, the Eh-pH diagrams of metal-water system of common elements in laterite nickel ore was summarized according to the reaction equations of different substances in aqueous solution, and the subsequent wet leaching process was guided. The following alkaline leaching experiments showed that under the conditions of 300 g/L NaOH concentration, 3.5 mL/g liquid–solid ratio, 160 °C leaching temperature and 1 h leaching temperature, 85.0 % of aluminum in mixed oxides can be leached and scandium can be enriched by 13 times. Finally, under the conditions of initial sulfuric acid concentration of 4 M, temperature of 100 °C, leaching time of 30 min and liquid–solid ratio of 4 mL/g, the leaching rates of Al, Ni, Mg, Co, Mn, Fe and Sc in alkaline leaching residue were 92.0 %, 97.5 %, 98.4 %, 92.3 %, 62.7 % and 68, respectively. A new procedure for treating lateritic nickel ore is proposed, allowing for thorough recovery and usage of important components. The technique is green and environmentally benign, resulting in closed-loop production of laterite-nickel ore treatment with numerous application possibilities.

Development of a new solution for determining the solubility limit of quercetin and other poorly soluble substances in aqueous solutions using the method for determining total organic carbon

Aim. Given the incompleteness of literature data on the solubility of quercetin and the importance of this physicochemical characteristic in the study of its bioavailability, there is a need to develop an alternative method for accurately quantifying the solubility limit of quercetin.
 Materials and methods. The concentration of quercetin in the samples was determined by directly determining the total organic carbon. For measurements, a total organic carbon analyzer 450 TOC (METTLER TOLEDO) was used with a range of measured values of 0.05–1000 ppbC µgC/l.
 Results. The exact limit of the solubility of quercetin, as a poorly soluble substance, has been established. Having previously measured the value of total organic carbon in the prepared solutions, we obtained data on the concentration of quercetin in solutions depending on the pH of the solution.
 Having built a graphical dependence of the measured values of the concentration of a substance on the pH values of the studied solutions, we obtain a mathematical equation of the reliance. Using the resulting function equation, one can approximate the concentration value of a substance with a pH value of 7.0. This value will be the solubility limit of the test substance for neutral media.
 Conclusions. As a result of the research, a new method was proposed for the quantitative determination of the solubility limit of a substance, with an accuracy not exceeding 5.0 %. The method is based on measuring the concentration of total carbon in acidic solutions with different pH values and subsequent approximation of the obtained dependence of the pH value equal to 7.0

Achieving a macroscopic Nondiffracting length from a microscopic All-fiber Bessel beam generator

The objectivesWe carried out a thorough parametric analysis by varying the dimension of the fiber optic Bessel-beam generator (BBG) to obtain the maximum a macroscopic nondiffracting length (NDL). BBG consisted of a single mode fiber (SMF) and serially concatenated coreless silica fiber (CSF), where multimode interference took place to shape the incoming fundamental LP01 mode to the Bessel-like mode propagating in water. Methodology usedFocusing on three wavelengths λ = 635 nm, 980 nm, and 1550 nm, we used the beam propagation method package for commercially available SMFs for each wavelength to find optimal CSF geometry. We also optimized the SMF parameters to increase the NDL further. Results obtainedUtilizing a simple all-fiber structure, we theoretically predicted that NDL in water reaching ~4 mm could be obtained from a microscopic fiber optic BBG. Their significanceThis result can be readily applied to optical manipulation of biological substances in aqueous solutions and laser material processing and imaging.

A Multicomponent Butyrylcholinesterase Preparation for Enzyme Inhibition-Based Assay of Organophosphorus Pesticides

A new method of producing butyrylcholinesterase (BChE) preparations, stable in storage and use, has been proposed. The BChE preparation is the enzyme co-immobilized with 0.2 M 5-5′-dithiobis (2-nitrobenzoic acid) in starch or gelatin gel. All experimental preparations retain enzyme activity for at least 300 d. The preparations based on gelatin gel show higher activity but lower sensitivity to the toxicants tested in this study compared to the starch gel-based preparations. A method has been proposed for integrated detection of anti-cholinesterase substances in aqueous solutions using the experimental preparation with immobilized BChE. After the additional incubation of the preparation with the immobilized enzyme in the solution of the analyte, the detection limits of malathion and pirimiphos-methyl determined using the IC20 values were below their maximum allowable concentrations—0.005 µM and 0.03 µM, respectively.

Screening and Discrimination of Perfluoroalkyl Substances in Aqueous Solution Using a Luminescent Metal-Organic Framework Sensor Array.

The extensive production and large-scale use of perfluoroalkyl substances (PFASs) have raised their presence in aquatic environments worldwide. Thus, the facile and reliable screening of PFASs in aqueous systems is of great significance. Herein, we designed a novel fluorescent sensor array for the rapid screening and discrimination of multiple PFASs in water. The sensor array comprised three highly stable zirconium porphyrinic luminescent metal-organic frameworks (i.e., PCNs) with different topological structures. The sensing mechanism was based on the static fluorescence quenching of PCNs by PFASs upon their adsorptive interactions. The fluorescence response patterns were characteristic for each PFAS because of their different adsorption affinities toward different PCNs. Through the interpretation of response patterns by statistical methods, the proposed PCN array successfully discriminated six different kinds of PFASs, each PFAS at different concentrations and PFAS mixtures at different molar ratios. The practicability of this array was further verified by effectively discriminating PFASs in two real water samples. Remarkably, the PCN sensors exhibited a very short response time toward PFASs (within 10 s) due to the ordered pore structure allowing fast PFAS diffusion. This study not only provides a facile method for rapid PFAS screening in waters but also broadens the application of luminescent metal-organic frameworks and array techniques in sensing fields.

Hydrothermal-assisted synthesis of sponge-like brookite for pseudo-Fenton decomposition of crystal violet under UV–light

In this report, brookite-titania nanosized structures were acquired using a two-step technique: hydrothermal treatment of carbon spheres impregnated with a titanium(IV) peroxo-complex solution and consequent heat treatment of the hydrothermal product in air for 4 h. The sample was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, nitrogen adsorption analysis and dynamic reflection spectroscopy. The sample exhibits a sponge-like morphology with agglomerates varying from 0.25 to 1.7μm in diameter. These agglomerates consist of brookite nanoparticles with an average diameter of 30 nm. The obtained particles demonstrate high photocatalytic activity in the pseudo-Fenton oxidation of crystal violet (the overall process constant is 0.0234 min−1 with 86% removal efficiency) and, thus, they are promising candidates for the catalytic decomposition of organic substances in aqueous solution.

DEUTERIUM AS A TOOL FOR CHANGING THE PROPERTIES OF PHARMACEUTICAL SUBSTANCES (REVIEW)

The review is devoted to the influence of the hydrogen isotope–deuterium on biological models of organisms and the biological activity of pharmaceutical substances.
 The positions of the influence of deuterium on the properties of active pharmaceutical ingredients and excipients are examined from different perspectives. The first position reflects an increase in the kinetic isotope effect (KIE) in processes involving known pharmaceutical substances in aqueous solutions with a deuterium/protium ratio (D/H) below natural. For the first time, the dose-response diagram shows the identity of deuterium with essential trace elements, when a deficiency and excess of an element reduces the organism's vitality. Improved kinetic characteristics are demonstrated for the molecular and organism levels of different hierarchical gradations. In particular, they consist in the possibility of increasing the dissolution rate of substances by influencing the carbohydrate mutarotation processes and the optical activity of chiral substances, increased accumulation of essential elements in medicinal plants and other processes associated with a possible change in metabolic pathways in the cell and the organism as a whole.
 The second considered position of the influence of deuterium is associated with the use of deuterated substances–new compounds or obtained by substitution of protium in known protium analogues. The KIE is presented, which is expressed in a decrease in the biotransformation rate as a result of deuteration, it allows predicting a rapid development of the new direction in the development of drugs. Having an identical therapeutic effect, deuterated analogs provide improved pharmacokinetic characteristics, such as reduced toxicity, blocked epimerization of optically active substances, and a change in the mechanisms of biotransformation. The obtained results make it possible to predict the mechanisms of the effect of deuterium on the biochemical transformations of pharmaceutical substances in the organism.

An electrocoagulation and electrooxidation treatment train to remove and degrade per- and polyfluoroalkyl substances in aqueous solution

This study examined the feasibility of a novel treatment train that combines electrocoagulation (EC) with electrooxidation (EO) treatment to remove and degrade per- and polyfluoroalkyl substances (PFASs) from water. Electrocoagulation with a zinc anode could effectively remove PFASs from water, and long-chain PFASs (C7–C10) tended to have a higher removal rate. Foam was generated when a relatively high current density (>1 mA cm−2) was applied to a relatively high PFAS concentration (each PFAS > 0.1 μM) during EC, which promoted the separation of PFASs from the bulk solution, especially for long-chain PFASs. Isotherm-like adsorption results indicated that competitive adsorption on floc occurred between PFASs when no foam was produced in a solution containing 10 different PFASs. Acid dissolution methods could recover and concentrate 10 PFASs in controlled volumes from both the floc and the foam, and it was also successfully applied in groundwater collected from a contaminated site. The concentrated PFASs in the acid solutions were efficiently destructed using EO treatment with a Ti4O7 anode at 10 mA cm−2, and no supplement of electrolyte was needed for the floc dissolved solution. This electrochemical-based process can economically separate, concentrate and destroy PFASs in groundwater and wastewater.

Structural features of the near-surface layers of highly diluted aqueous solutions

Particular importance currently is given to highly diluted aqueous solutions due to the fact that not only the presence of clusters, but also more complex structures – associates, bastons, etc., have been found in them. However, the phenomenon of the appearance of new physicochemical, spectral, diffraction, refractometric and other effects related to heterogeneity in the changing inhomogeneous structure of the surface layers of aqueous solutions is not fully understood. The paper presents the results of vertical laser sensing of drops of hydrophilic substances highly diluted in water, which made it possible to detect clathrate nano-formations in various combinations, the nature of which is still insufficiently clear. We studied droplets of distilled micellar water, hydrogen peroxide, an aqueous solution of glycerol, ethanol, etc. At low concentrations of hydrophilic substances in aqueous solutions their molecules are embedded into the interstices of the water lattice without causing destruction of its structure. It is found that the dissolution mechanism continued only to a certain critical concentration after which “saturation” occurred. A further increase in the content of dissolved substances in aqueous solutions leads to the destruction of the ordered structure, and the excess molecules of the hydrophilic substance, combined together, form complex aggregates or their “islands”.

Formation of clathrate structures in surface layers of heavily diluted aqueous solutions

The paper presents the results of experimental studies related to the formation of clathrate structures in highly diluted hydrophilic aqueous solutions. A method based on the interference of laser beams transmitted through a water lens of various configurations is applied. It shown that the studied solutions have properties associated with the self-organization of the structure in clathrate states due to the cooperative effect of changes in the inhomogeneous network of hydrogen bonds. It is found that in the range of small concentrations of dissolved substances in aqueous solutions, in spite of some stabilization of the structures in the formed clathrates depending on the number of interacting molecules, the formation of associates of various shapes is possible. An increase in the content of dissolved substances in aqueous solutions leads to the destruction of the ordered structure, and the excess molecules of the hydrophilic substance, combined together, form complex aggregates or their “islands”.

Structure-activity relationship of coptis alkaloid bitterness inhibited by mPEG-PLLA

Inhibition of bitterness is a significant measure to improve the compliance and clinical efficacy of traditional Chinese medicine(TCM) decoction. According to the characteristics of TCM decoction, such as high dispersion of bitterness components, multi-component bitterness superposition and strong instantaneous stimulation, the research group put forward a new strategy to inhibit bitterness in the early stage based on the self-assembly characteristics of amphiphilic substances in aqueous solution, in order to reduce the distribution of bitterness components in real solution and achieve the purpose of bitter-masking. It was found that the bitter-masking effect of amphiphilic substances was different on the bitter compounds of various structures. Therefore, it was speculated that there might be a certain relationship between the bitter inhibition effect and the substrate structure. In this paper, the interaction between mPEG-PLLA and five bitter alkaloids(bamatine, jatrorrhizine, berberine, epiberberine and coptisine) in Coptidis Rhizoma was studied to explore the effect of substrate structure on the inhibition of bitterness. The sensory test of volunteers was used to determine the bitter-masking effect of mPEG-PLLA on the decoction of Coptidis Rhizoma and its main bitter alkaloids. The molecular docking and molecular force field were applied to locate the bitter groups and the bitter-masking parts. The relationship between the bitter strength and the structure was analyzed by the surface electrostatic potential of the bitter alkaloids, and the correlation between the bitter-masking effect and the structural parameters of the bitter components was explored by factor analysis, so as to clarify the structure-activity relationship of mPEG-PLLA in masking the bitterness of coptis alkaloids. It was found that mPEG-PLLA had significant taste masking effect on the decoction of Coptidis Rhizoma and five alkaloids. The masking effect was obviously related to the structure of different alkaloids: the effect increased with the increase of the number of hydrogen donors, rotatable bonds, molecular weight, and hydrophobicity, and decreased with the increase of surface electrostatic potential, electrophilicity and binding energy with bitter receptors. In this study, the influence of alkaloid structure of Coptidis Rhizoma on the butter-masking effect of mPEG-PLLA was preliminarily elucidated, providing a scientific basis for better exerting the bitter-masking effect of amphiphilic block copolymers.

Non-Ostwald Behavior of Disperse Systems in Evaporation and Crystallization of Droplets of Water–Organic Solutions

This Letter describes experiments with aqueous solutions of organic substances demonstrating a non-Ostwald behavior under which the stability of small droplets during evaporation and crystallization is higher than that of large droplets. Such a behavior has been described earlier for aqueous solutions of some inorganic salts. It is shown that the non-Ostwald behavior has a common thermodynamic nature with Ostwald ripening and should be observed in disperse systems with a complex chemical composition. The features of reproduction of the non-Ostwald behavior related to the surface activity of organic substances in aqueous solutions are described. The studied regularities can be used upon preparation of solutions of organic and bioorganic substances with a concentration significantly higher than their solubility under normal conditions, as well as for the formation of narrow size distributions in different spray processes.

The Influence of Deuterium on the Properties of Pharmaceutical Substances (Review)

Introduction. The study discusses the hydrogen isotope 2 H effect on the biological activity of pharmaceutical substances.Text. Two aspects of the deuterium effect on the properties of active pharmaceutical ingredients and excipients are considered. The first one involves the use of deuterated substances, new compounds or substituted counterparts. Replacing protium with deuterium is used to reduce the rate of biotransformation. The kinetic isotope effect (KIE), expressed in a decrease in the rate of biotransformation as a result of deuteration, allows us to predict the rapid development of new directions in the development of pharmaceuticals. With the same therapeutic effect, an improvement in pharmacokinetic characteristics, a decrease in toxicity, a blocking of the epimerization of optically active substances, a change in the mechanisms of action are observed. The second aspect of the deuterium effect is associated with an increase in KIE of known pharmaceutical substances in aqueous solutions with a deuterium/protium ratio (D/H) lower than in natural water. For the first time, dose-response diagrams for deuterium demonstrate identity with essential microelements. There is a safety zone for the certain D/H relationship, beyond which the organism's vitality decreases. Improved kinetic characteristics are demonstrated for molecular level and for biological objects of various hierarchical levels. In particular, they include the possibility of increasing the dissolution rate of substances, the influence on the processes of mutarotation and the optical activity of chiral substances, the degree of accumulation of necessary elements in medicinal plants, and other processes.Conclusion. The results make it possible to predict the mechanisms of deuterium influence on the biochemical transformations of pharmaceutical substances in the body.

Porous Graphitized Carbon for the Separation and Preconcentration of Hydrophilic Substances

The review discusses preparation methods, structure, and features and prospects of using carbon adsorbents, primarily, porous graphitized carbon, for the separation and preconcentration of hydrophilic organic substances in aqueous solutions. The mechanisms of the adsorption of such substances, possibilities of using porous graphitized carbon under extreme conditions, and numerous examples of solving specific problems are presented.

Hydrothermal fabrication of novel three-dimensional graphene oxide-pentaerythritol composites with abundant oxygen-containing groups as efficient adsorbents

Three-dimensional (3D) graphene oxide-pentaerythritol (GO-PER) composites with abundant oxygen-containing functional groups (such as carboxyl, hydroxyl, carbonyl, epoxy) were successfully prepared by a hydrothermal self-assembly method. The enrichment performances of GO-PER composites for rare earth elements (REEs) and phenols were investigated by batch adsorption experiments. The adsorption of REEs and phenols could reach equilibrium in 30 min and 60 min at room temperature, respectively. Furthermore, GO-PER composites exhibited excellent pH stability. The adsorption capacities of GO-PER composites were 27.92, 30.44, 43.2, 48.08 and 52.4 mg g−1 for La3+, Y3+, Nd3+, Er3+ and Yb3+, respectively. The adsorption capacities of GO-PER composites for phenols including 3-nitrophenol, hydroquinone and tert-butylphenol (TBHQ) were 61.1, 42.35 and 29.76 mg g−1, respectively. Scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) specific surface area (SSA) analysis and Zeta potential analysis were used to characterize the physicochemical properties of the samples and propose the adsorption mechanism. The adsorption of REEs by GO-PER composites might be due to electrostatic attraction and surface complexation, while π-π stacking interaction and hydrogen bonding mainly contributed to the adsorption of phenols. Recycling experiments showed that GO-PER composites possessed excellent reusability and high stability. The as-prepared GO-PER composites could be potentially used to efficiently enrich or remove REEs and organic substances in aqueous solutions.

Detection of low-level humic acid in water using room temperature-synthesized copper (I) oxide colloids

Abstract

Three-dimensional porous graphene oxide-maize amylopectin composites with controllable pore-sizes and good adsorption-desorption properties: Facile fabrication and reutilization, and the adsorption mechanism

Three-dimensional (3D) porous graphene oxide-maize amylopectin (GO-MA) composites with controllable pore-sizes composites in the range of 6–40 nm were prepared by facile hydrothermal-assisted assembly approaches. The morphologies, pore sizes, specific surface area (SSA) and compositions of GO-MAx:y composites with and different GO-to-MA mass ratios (x:y) were characterized by scanning electron microscopy (SEM), N2 adsorption-desorption isotherms, Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). To reveal the adsorption-desorption mechanism, effects of contact time, temperature, initial adsorbate concentration, pH value of the solution on the adsorption process were studied in detail. The adsorption capacities of 3D GO-MA20:1 composite for organic contaminants including tert-butyl hydroquinone (TBHQ), p-aminophenol (PAP), p-nitrophenol (PNP), o-nitrophenol (MNP), hydroquinone (HQ), alizarin red S (ARS) and neutral red (NR) were 22.17, 116.4, 44.78, 36.96, 16.10, 39.92 and 24.23 mg g−1, respectively. The adsorption capacities of GO-MA30:1 composite for inorganic substances including Pb2+, Mn2+, Cr2O72−, Cd2+, Cu2+, Nd3+, La3+, Y3+, Yb3+ and Er3+ were 84.76, 7.92, 13.6, 17.64, 30.56, 25.52, 12.48, 16.96, 23.32 and 30.32 mg g−1, respectively. In addition, GO-MAx:y composites also exhibited high mechanical properties and good reusability. Consequently, GO-MAx:y composites could be used as reusable adsorbents for removal/enrichment inorganic/organic substances in aqueous solutions.

Evaluation of adsorption of organic solvents to modified hydrophobic silica adsorbents based on Hansen solubility parameter

• Adsorption of organic substances in aqueous solution was carried out using hydrophobic silica adsorbent. • Adsorbed amount was estimated using HSP theory. • An adsorption amount estimation formula using the difference R a of HSP values was constructed. • It was suggested that affinity is an important factor in adsorption. Adsorption is an effective methodology for the removal of organic matter. Several studies have shown that adsorption performance is dependent on pore size, specific surface area, and the affinity between the adsorbent and adsorbed material. In this study, we concentrated on the effect of the affinity between the surface of the adsorbent and the adsorbed matter by examining the adsorption of organic solvents from organic/aqueous mixtures using three types of hydrophobic silica adsorbents. The Hansen solubility parameters (HSPs) of the adsorbents were determined using the group contribution method. A linear relationship between the logarithm of the amount of adsorbed organic solvent and the difference between the HSP values of the organic solvents and adsorbents was obtained with a high correlation coefficient. These experimental results suggest that the affinity between the adsorbent and adsorbed matter can be well-described by the HSPs of the components.