CPC Concentration Research Articles

Effects of Neonicotinoid Pesticide Metabolic Compounds on Medaka (Oryzias latipes) Embryo Development.

Neonicotinoids, including imidacloprid, are pesticides that resemble nicotine and undergo slight chemical alterations through metabolic changes in the environment. However, the effects of these metabolites on organisms remain unknown. In this study, we assessed the developmental processes of medaka embryos exposed to neonicotinoid metabolites. The target compounds were imidacloprid metabolites: 2-chloro-5-pyridine carbaldehyde (CPC) and 6-chloronicotinic acid (6-CNA). Medaka embryos within 6 h of fertilization were exposed to the compounds, and their developmental processes were observed under a stereomicroscope. Medaka embryos exposed to 5 mg/L CPC showed no abnormalities compared to the controls. Contrastingly, medaka embryos exposed to 10, 15, and 20 mg/L CPC showed abnormalities such as thrombus formation, asymmetry, disorganized development of the eyeballs, and low blood flow. This trend was more pronounced at higher CPC concentrations. On the other hand, embryos exposed to 80 and 160 mg/L 6-CNA showed no abnormalities until day 7 of exposure. However, on day 8 of exposure, sudden embryo death was observed. Both compounds may have bound to acetylcholine receptors as agonists; however, their effects were different. CPC caused abnormal development and 6-CNA caused inhibition of hatching gland development and/or synthesis of the hatching enzyme.

Inhibition effect of plant distillates on 90/10 Cu-Ni alloy in acidic chloride media

Citrus paradisi and Cymbopogon distillates were admixed in ratio 1:1 and assessed for their inhibition effect on Cu-Ni cupronickel alloy in 0.25 M H 2 SO 4 –3.5% NaCl electrolyte. Results revealed the distillates effectively inhibited the Cu-Ni alloy at 2–5% CPC concentrations. The degradation rate of Cu-Ni alloy without distillate is 0.373 mm/y whereas at 1% concentration, the degradation rate decreased to 0.140 mm/y (1.37 × 10 −5 A/cm 2 ) corresponding to inhibition efficiency of 62.46%. At 2–5% concentration, inhibition efficiency ranged between 80.47 and 95.58%. The distillate displayed mixed-type inhibition performance coupled with significant suppression of cathodic reduction reactions. Thermodynamic calculations showed the distillates adsorbed unto the Cu-Ni alloy by chemisorption according to Langmuir and Freundlich adsorption isotherms (correlation coefficients above 0.8). Gibbs free energy indicate increase lateral attraction effect among the distillate molecules with respect to #concentration. Open circuit potential curves showed the distillates increased the thermodynamic instability of Cu despite effective inhibition performance.

Highly transparent antioxidant high internal phase emulsion gels stabilized solely by C-phycocyanin: Facilitated formation through subunit dissociation and refractive index matching

In the work, we report a kind of novel highly transparent oil-in-water (O/W) HIPE gels stabilized solely by c -phycocyanin (CPC; an important biliprotein pigment), with a great potential to act as outstanding containers for heat or UV labile lipophilic bioactives. The CPC was solubilized in 6 M urea solution containing 40 wt% glycerol, in order to achieve the improved emulsification performance of the protein, as well as the transparency of the resultant HIPE gels through the refractive index (RI) matching between the aqueous and dispersed oil (dodacane) phases. Using 6 M urea containing 40 wt% glycerol as the aqueous phase, the transparent HIPE gels could be formed at the CPC concentration ( c ) as low as 0.1 wt%, and oil fractions in the range 0.6–0.86. In the protein-poor regime, e.g., c < 0.5 wt%, increasing the c led to a progressive decrease in emulsion size, as well as strengthening of gel network, while in the protein-rich regime ( c = 0.5–1.0 wt%), the emulsion droplet and gel stiffness were independent of the c . The as-fabricated transparent HIPEs (gels) exhibited an outstanding oxidative protection to encapsulated β -carotene against degradation upon extensive heating or UV irradiation. • A kind of novel transparent antioxidant HIPE gels stabilized by c -phycocyanin was reported. • The transparency of HIPE gels was achieved by a RI matching technique with urea and glycerol. • The emulsification performance of c -phycocyanin was remarkably improved by the presence of 6 M urea. • The chemical stability and antioxidant capacities of c-phycocyanin were unaffected by the usage of urea and glycerol. • The as-fabricated transparent HIPE gels exhibit a great potential in cosmetic and other formulations.

Hexadecylpyridinium Chloride Mediated Hydrothermal Synthesis of NaYF₄:Yb, Er Nanocrystal and Their Luminescent Properties.

Upconversion nanocrystals with uniform size and hydrophilic surface have potential applications in biological medical engineering. In this study, hydrophilic NaYF₄:Yb, Er nanospheres were synthesized via hexadecylpyridinium chloride (CPC) mediated hydrothermal process. The synthesized NaYF₄:Yb, Er upconversion nanospheres (UCNSs) were characterized by various characterization methods. Results showed that the synthesized UCNSs exhibited a uniform sphere-like structure with average diameter of ~250 nm. The surface of UCNSs was captured by CPC molecule indicating hydrophilic properties of UCNSs. The spherical UCNSs composed of mixed phase (α+β) NaYF₄ nanocrystals. This is the novel study for synthesis of NaYF₄:Ln3+ crystal employing CPC as ligand. Moreover, the effect of CPC concentration on synthesis of UCNSs was investigated by comparatively studying morphology, crystal phase and luminescent properties of desired sample prepared under different experimental conditions. It was found that high concentrations of CPC ligands were more favorable for forming NaYF₄ crystal nanospheres with morphology that is more regular, have smoother surface, with higher crystallinity and better upconversion fluorescent properties. The possible growing mechanism was proposed and growing of NaYF₄:Yb, Er nanospheres followed the classical Ostwald ripening process.

Acute Exercise in Hypobaric Hypoxia Attenuates Endothelial Shedding in Subjects Unacclimatized to High Altitudes.

Travel of unacclimatized subjects to a high altitude has been growing in popularity. Changes in endothelial shedding [circulating endothelial cells (ECs)] and hematopoietic stem and progenitor cells (CPCs) during physical exercise in hypobaric hypoxia, however, are not well understood. We investigated the change in ECs and CPCs when exposed to high altitude, after acute exercise therein, and after an overnight stay in hypobaric hypoxia in 11 healthy unacclimatized subjects. Blood withdrawal was done at baseline (520 m a.s.l.; baseline), after passive ascent to 3,883 m a.s.l. (arrival), after acute physical exercise (±400 m, postexercise) and after an overnight stay at 3,883 m a.s.l. (24 h). Mature blood cells, ECs, and CPCs were assessed by a hematology analyzer and flow cytometry, respectively. The presence of matrix metalloproteinases (MMPs), their activity, and hematopoietic cytokines were assessed in serum and plasma. EC and CPC concentrations significantly decreased after exercise (p = 0.019, p = 0.007, respectively). CPCs remained low until the next morning (24 h, p = 0.002), while EC concentrations returned back to baseline. MMP-9 decreased at arrival (p = 0.021), stayed low postexercise (p = 0.033), and returned to baseline at 24 h (p = 0.035 to postexercise). MMP-activity did not change throughout the study. Circulating MMP-9 concentrations, but not MMP-activity, were associated with EC concentrations (rrm = 0.48, p = 0.010). CPC concentrations were not linked to hematopoietic cytokines. Acute exercise at high altitude attenuated endothelial shedding, but did not enhance regenerative CPCs. Results were not linked to endothelial matrix remodeling or CPC mobilization. These results provide information to better understand the endothelium and immature immune system during an active, short-term sojourn at high altitude.

Circulating adult stem and progenitor cell numbers\u2014can results be trusted?

BackgroundWithin the last years, the interest in physical exercise as non-invasive stimulus influencing circulating hematopoietic stem and progenitor cell (CPC) concentrations has constantly grown. Cell estimates are often derived by determining the subgroup of CPC as percent lymphocytes (LYM) or mononuclear cells (MNC) via flow cytometry and back calculation over whole blood (WB) cell counts. However, results might depend on the used cell isolation technique and/or gating strategy. We aimed to investigate MNC loss and apoptosis during the flow cytometry sample preparation process preceded by either density gradient centrifugation (DGC) or red blood cell lysis (RBCL) and the potential difference between results derived from back calculation at different stages of cell isolation and from WB.MethodsHuman blood was subjected to DGC and RBCL. Samples were stained for flow cytometry analysis of CPC (CD34+/CD45dim) and apoptosis analysis (Annexin V) of MNC and CPC subsets. MNC and LYM gating strategies were compared.ResultsBoth DGC as well as RBCL yielded comparable CPC concentrations independent of the gating strategy when back calculated over WB values. However, cell loss and apoptosis differed between techniques, where after DGC LYM, and monocyte (MONO) concentrations significantly decreased (p < 0.01 and p < 0.05, respectively), while after RBCL LYM concentrations significantly decreased (p < 0.05) and MONO concentrations increased (p < 0.001). LYM apoptosis was comparable between techniques, but MONO apoptosis was higher after DGC than RBCL (p < 0.001).ConclusionsInvestigated MNC counts (LYM/MONO ratio) after cell isolation and staining did not always mimic WB conditions. Thus, final CPC results should be corrected accordingly, especially when reporting live CPC concentrations after DGC; otherwise, the CPC regenerative potential in circulation could be biased. This is of high importance in the context of non-invasively induced CPC mobilization such as by acute physical exercise, since these cell changes are small and conclusions drawn from published results might affect further applications of physical exercise as non-invasive therapy.

Combining NSAM and CPC concentrations to determine airborne nanoparticle count median diameter: Application to various laboratory and workplace aerosols

ABSTRACTBecause nanomaterials have been increasingly developed and used in many technology and industry sectors over the last 20 years, an increasing number of workers is likely to be exposed to airborne nanoparticles. In addition, the question of the nanomaterial characteristics that should be assessed in epidemiological studies remains open. Thus, assessing occupational exposure to airborne nanoparticles will not only rely on mass concentration and chemical composition. Rather, key parameters, such as particle size, have to be included in measurement strategies.We previously proposed a methodology to estimate the Count Median Diameter (CMD) of an aerosol based on the simultaneous size-integrated measurement of two particle concentrations, lung-deposited surface area, and number, thanks to field-portable, commercially available aerosol instruments (Nanoparticle Surface Area Monitor/Condensation Particle Counter combination).In addition to previous work, this study investigates the case of various polydisperse metal oxides, organic oil, and salt particles with CMDs ranging from 16–410 nm. Once corrected, the CMDs derived from the NSAM/CPC agree within ±20% with regard to the reference electrical mobility equivalent diameter, regardless of aerosol composition, morphology, or geometric standard deviation (GSD).Furthermore, the field-applicability of the method was tested through 6 sets of experimental data stemming from workplace measurement campaigns where different materials were produced and handled (TiO2, SiO2, Ag, Multi-Walled Carbon Nanotubes—MWCNT), covering a range of CMDs between 40 and 190 nm. All situations considered, the approach based on the combination of a NSAM and a CPC leads to a satisfying estimation of particle CMD, within ±20% compared to reference CMD.

Characterisation of particle size distributions and corresponding size-segregated turbulent fluxes simultaneously with CO2 exchange in an urban area

Number and mass particle concentrations and fluxes were measured, simultaneously with CO2 concentration and flux, in the urban area of Lecce (Italy). The measurements of the turbulent exchanges of atmospheric particles and gas were performed with an eddy-covariance station located near the busiest road of the town. For the smaller particles, the diurnal evolution of the particle number concentrations and fluxes shows a clear correlation with human activities, in particular vehicular traffic, which is the obvious candidate as the source of the two clear peaks in the CPC concentration in the morning and in the evening. The fluxes were upward for all the measurement period, even though small net deposition was observed for larger particles and during weekend. For the CPC, the correlation with the traffic daily pattern is extremely strong. The city is a continuous particle source. The data analysis seems also to suggest the presence of local urban nucleation events. CO2 and particle concentrations were larger at low wind velocity, instead, fluxes were larger at high wind velocity. This opposite behaviour suggests that the influence of local urban emissions is larger on fluxes with respect to concentrations. The average daily patterns of CO2 concentration show an overlap between biogenic cycle and urban emissions. Again, traffic appears to be the dominant source for fluxes and the urban area is a net source of CO2.

Optimization Design and Simulation Study of a CPC for LFR System

A CPC for LFR system was designed and its mathematical model was established. Maximum acceptance angle and truncation ratio was optimized to 45° and 0.75, which two elements mainly affect the optical performance of CPC. Moreover, the non-uniform of incident angle can considerably improve the CPC concentration ratio. Results show that the CPC with 475.49mm opening width could achieve a high concentrate ratio reach up to 80.15%. This conclusion was further verified by an experimental measurement results.

Influence of Surfactants on Dye Removal and Growth of Aspergillus versicolor – an Effective Way to Decolorize Textile Dye

AbstractThis study examined the reactive dye decolorization activities of sodium dodecyl sulfate (anionic), cetylpyridinium chloride monohydrate cetylpyridinium chloride monohydrate (CPC) (cationic) surfactants, and their influence on fungal growth. The effect of CPC on Remazol Blue (RB) bioremoval by Aspergillus versicolor was investigated in low‐cost molasses medium. The optimum pH (3–7) and CPC (0.1–1 mM) concentrations for fungal RB decolorization were achieved in molasses medium with 50 mg/L RB. It was observed that the CPC effectively removed RB due to electrostatic interactions and it was well tolerated by fungus. Maximum decolorization in the presence of CPC occured at pH 6. Increasing the toxic CPC concentrations (0, 0.1, 0.25, 0.5, 1 mM) decreased fungal growth from 5.08 to 2.87, 1.40, 0.21, and 0.07 mg/L dry biomass, respectively, but enhanced fungal decolorization, respectively (63.2, 78.7, 92, 95.75, and 98.9%). As the augmentation of CPC concentration reduced energy costs by reducing effective decolorization period from 96 to 24 h, surfactant stimulated fungal decolorization method may provide highly efficient, inexpensive, and time‐saving procedure in treatment of textile effluents.

Precipitation of cetyl (hexadecyl) pyridineum chloride using mono and divalent oxyanions

Experimental investigations have been carried out to observe the performance of precipitation behavior of potassium permanganate (KMnO 4) and potassium dichromate (K 2Cr 2O 7) in cetyl (hexadecyl) pyridineum chloride (CPC) solution. As in the case of Al 3+-dodecylbenzenesulfonate systems [P. Somasundaran, K.P. Anathapadmanabhan, M.S. Celik, Langmuir 4 (1988) 1061–1063], the precipitation is found to be caused by interaction of CPC micelles with oxyanions. The counter oxyanions have a strong tendency to bind themselves to the surface of cationic CPC micelles. This lowered the free oxyanion concentration in solution. Therefore, to start precipitation, higher oxyanion concentration is required for higher CPC concentration. The effects of temperature, concentrations of both counter ions and CPC on the precipitation have been studied in detail. It has been observed that at CPC to KMnO 4 concentration ratio of 1.0 (concentration of CPC and KMnO 4 is 400 ppm), the percentage precipitation of CPC is around 99.3 at 30 °C. The percent precipitation of CPC decreases to about 94% when temperature increases to 70 °C at the same condition. The extent of CPC precipitation increases at the same experimental condition when K 2Cr 2O 7 is used instead of KMnO 4.

Micellar enhanced ultrafiltration of eosin dye using hexadecyl pyridinium chloride

Surfactant-based separation of toxic eosin dye is studied to estimate the potential of micellar enhanced ultrafiltration (MEUF) using cetyl(hexadecyl) pyridinium chloride (CPC) as the cationic surfactant. The optimum feed CPC concentration is found from the experimental results of pure CPC solution in a batch cell. It is in the range of 10–20 kg/m 3 to have a reasonable permeate flux and lower surfactant concentration in the permeate. Selecting 10 kg/m 3 as the feed surfactant concentration, MEUF experiments are conducted to study the retention characteristics of eosin dye in the continuous cross flow system. The effects of operating conditions, i.e., feed dye concentration, operating pressure and cross flow rate on the permeate flux and observed retention of dye are investigated.

Binding of ionic surfactants to purified humic acid

The binding of organic contaminants to dissolved humic acids reduces the free concentration of the contaminants in the environment and also may cause changes to the solution properties of humic acids. Surfactants are a special class of contaminants that are introduced into the environment either through wastewater or by site-specific contamination. The amphiphilic nature of both surfactants and humic acids can easily lead to their mutual attraction and consequently affect the solution behavior of the humics. Binding of an anionic surfactant (sodium dodecyl sulfate, SDS) and two cationic surfactants (dodecyl- and cetylpyridinium chloride, DPC and CPC) to purified Aldrich humic acid (PAHA) is studied at pH values of 5, 7, and 10 in solutions with a 0.025 M ionic strength ( I). Monomer concentrations of the surfactants are measured with a surfactant-selective electrode. At I=0.025 M, no significant binding is observed between the anionic surfactant (SDS) and PAHA, whereas the two cationic surfactants (DPC, CPC) bind strongly to PAHA over the pH range investigated. The binding is due both to electrostatic and hydrophobic attraction. The initial affinity increases with increasing pH (i.e., negative charge of PAHA) and tail length of the surfactant. Binding reaches a pseudo-plateau value (2–5 mmol/g) when the charge associated with PAHA is neutralized by that of the bound surfactant molecules. The pseudo-plateau values for DPC and CPC are very similar and depend on the solution pH. The cationic surfactant–PAHA complexes precipitate when the charge neutralization point is reached. This occurs at approximately 10% of the critical micelle concentration or CMC. This type of phase separation commonly occurs during surfactant binding to oppositely charged polyelectrolytes. For CPC, the precipitation is complete, but in the case of DPC, a noticeable fraction of PAHA remains in solution. At very low CPC concentrations (less than 0.1% of the CMC), CPC binding to PAHA is cooperative. The investigated range of concentrations for DPC was too limited to reach a similar conclusion. The results of this study demonstrate that the fate of humic acids will be strongly affected by the presence of low cationic surfactant concentrations in aqueous environmental systems.

Behavior of Poly(N-vinylcaprolactam-co-methacrylic acid) Macromolecules in Aqueous Solution: Interplay between Coulombic and Hydrophobic Interaction

Dynamic light scattering measurements have been performed for aqueous solutions of linear copolymer of N-vinylcaprolactam (VCa) and methacrylic acid (MA) with variable composition (i.e., charge degree of polymer chain). The swelling behavior of macromolecules was investigated as a function of both the solution pH value and fraction of methacrylic acid groups. It was shown that these copolymers are thermosensitive, and intermacromolecular aggregation takes place at the temperature increase. They exhibit compositionally dependent swelling behavior as a function of both pH and temperature. The behavior of studied copolymer was explained by the partial formation of ion pairs. The dependence of hydrodynamic diameter on pH of the solution is nonmonotonic. In acidic media at room temperatures we observed the intermolecular aggregation of copolymers accompanied by a sharp increase of the light scattering intensity. In alkaline media intermacromolecular aggregation is observed at higher temperatures. The effect of oppositely charged surfactant (cationic cetylpyridinium chloride, CPC) on the swelling behavior of PVCa−MA macromolecules was investigated under various conditions of pH and temperature. The association of PVCa−MA macromolecules was demonstrated to be a function of pH and CPC concentration. The equilibrium size of copolymer−CPC aggregates was found. It was shown that the size of intermacromolecular aggregates containing copolymers and CPC depends only weakly on the variation of ambient conditions (pH, surfactant, or copolymer concentration). The effect of temperature on the stability of copolymer/surfactant complexes was studied. This result is compared with recent theoretical predictions.

Enrichment of an amino acid by micellar-enhanced ultrafiltration

Abstract It is difficult to enrich low molecular weight solutes by membrane processes with sufficient speed under low applied pressure. However, combination of a solute with micelles of a surfactant enables enrichment of the solute into the retentate solution by ultrafiltration. The micellar-enhanced ultrafiltration of an amino acid, l -tryptophan, was carried out in a batch-stirred cell. The characteristics of the ultrafiltration of the micelles were examined with respect to the permeation flux and micelle rejection. As the concentration of the micelle-forming substance, cetylpyridinium chloride monohydrate (CPC; MW 358), in the retentate solution increased, the permeation flux decreased but the concentration in the permeate solution was limited. The effect of membrane molecular weight cut-off (MWCO) on permeation flux was obvious at low CPC concentrations but only slight at high concentrations. l -Tryptophan (MW 204) combined with CPC micelles to be retained by membranes of MWCO 20,000 as well as MWCO 10,000; there was no difference in rejection between the two membranes. The rejection coefficient was estimated as a function of the solubilization constant and the micelle concentration. The rejection coefficient increased with increasing CPC concentration but too high CPC concentrations resulted in the leakage of CPC into the permeate solution.

Transient electric light scattering. III. Investigation of the stability of palygorskite colloid solutions

The transient light scattering method is used for the preliminary study of the stability of palygorskite colloid solution to which the cationic surface active substance cetyl pyridinium chloride (cpc) was added. The cpc concentration at which the minimum colloid stability was found (10 −5 mole/liter) by the variation of the intensity of the scattered light coincided with the presence of a minimum in the value of the electric polarizability. The parallel electrophoretic measurements showed that at the same concentration the palygorskite particles had a considerable ζ-potential (about −30 mv) and that the isoelectric point was at a cpc concentration of 1.5 × 10 −4 mole/ liter at which the solution was obviously far more stable. The reality of the minimum of the electric polarizability and the difference between the isolectric point and the minimum polarizability points have been discussed and an explanation has been suggested for the correlation of the minimum colloid stability to the minimum electric polarizability point. We hope that this study not only demonstrates the possibilities of the electro-optic methods for the study of the stability of the disperse systems, but also provides important evidence on the probable importance of the dipolar interactions (due to interfacial electric polarizability) for colloid stability.