Amphiphilic Properties of Dodecylammonium Chloride/4-(1-Pentylheptyl) Benzene Sodium Sulfonate Aqueous Mixtures and Study of the Catanionic Complex

Surfactants are often used in supramolecular chemistry, due to their ability to self-organize. Surfactant molecules aggregate spontaneously and reversibly to adopt a defined intermolecular arrangement. In this work, general phase behavior, adsorption and association in aqueous mixtures of dodecylammonium chloride, DACl and sodium 4-(1-pentylheptyl) benzenesulfonate, NaDBS, were studied by a combination of techniques including surface tension and conductivity measurements, light scattering and optical microscopy. The strong synergistic properties of the system were brought out with the Regular Solution Theory. Various colloidal objects are observed in wide range of composition: conventional small vesicles, large giant multilamellar or multivesicular vesicles. An excess of NaDBS provides extremely large tubular and elongated multilamellar vesicles. The new catanionic 1:1 complex, dodecylammonium-4-(1-pentylheptyl) benzenesulfonate, formed in the equimolar conditions is a result of intramolecular charge neutralization. The thermal properties of this solid compound were examined by thermal polarizing microscopy, differential scanning calorimetry, and X-ray diffraction. The most probable ion-pair amphiphilic cluster of the crystal smectic phase, at room temperature, consists of ionic groups formed in ordered layers with dodecyl chains packed into somewhat disordered layers, tilted to the layer plane.     

Phase Transitions in Liquid Crystal Doped with Magnetic Particles of Different Shapes in Combined Electric and Magnetic Fields

We have studied the influence of electric and magnetic fields on the orientational structure of ferronematics based on a thermotropic nematic 4-trans-4 \(^{\prime }\) -n-hexylcyclohexyl-isothiocyanato-benzene (6CHBT). The 6CHBT liquid crystal has been dissolved in phenyl isothiocyanate and doped with rod-like or chain-like magnetic particles. In such a mixture, the phase transition from an isotropic to a nematic phase is via a droplet state, i.e., coexistence of nematic and isotropic phases. The obtained results showed that a combination of the electric and magnetic fields can change the character of a phase transition from the isotropic to the nematic phase via the droplet state in such systems. Moreover, magneto-dielectric measurements of structural transitions showed the magnetic field induced a shift of the phase transition temperature from the isotropic to the droplet state.     

Miscibility in blends of sulfonylated poly(2,6-dimethyl-1,4-phenylene oxide) and poly(p-bromostyrene-co-o-bromostyrene)

Miscibility in blends of random copolymers of p-bromostyrene (pBrSt) and o-bromostyrene (oBrSt) [P(pBrSt-co-oBrSt)] with partially sulfonylated poly(2,6-dimethyl-1,4-phenylene oxide) (SPPO) have been studied by differential scanning calorimetry (DSC). For an SPPO of given degree of sulfonylation, a miscibility window in terms of the isomeric composition of the brominated copolymer was seen; the location and width of the window was a function of sulfonylation. In general, copolymers with a higher content of pBrSt exhibit miscibility with SPPOs with higher degrees of sulfonylation. Upon annealing to temperatures of 280° and 320°C, only small changes in the miscibility regime were observed. The miscibility behavior was analyzed on the basis of the mean-field theory in terms of the individual segmental interaction parameters. © 1994 John Wiley & Sons, Inc.     

Depolymerization of insulin amyloid fibrils by albumin-modified magnetic fluid

Pathogenesis of amyloid-related diseases is associated with the presence of protein amyloid deposits. Insulin amyloids have been reported in a patient with diabetes undergoing treatment by injection of insulin and causes problems in the production and storage of this drug and in pplication of insulin pumps. We have studied the interference of insulin amyloid fibrils with a series of 18 albumin magnetic fluids (MFBSAs) consisting of magnetite nanoparticles modified by different amounts of bovine serum albumin (w/w BSA/Fe?O? from 0.005 up to 15). We have found that MFBSAs are able to destroy amyloid fibrils in vitro. The extent of fibril depolymerization was affected by nanoparticle physical-chemical properties (hydrodynamic diameter, zeta potential and isoelectric point) determined by the BSA amount present in MFBSAs. The most effective were MFBSAs with lower BSA/Fe?O? ratios (from 0.005 to 0.1) characteristic of about 90% depolymerizing activity. For the most active magnetic fluids (ratios 0.01 and 0.02) the DC50 values were determined in the range of low concentrations, indicating their ability to interfere with insulin fibrils at stoichiometric concentrations. We assume that the present findings represent a starting point for the application of the active MFBSAs as therapeutic agents targeting insulin amyloidosis.     

Improved structured light 3D scanner with application to anthropometric parameter estimation

Obtaining accurate anthropometric body segment parameters in a fast and reliable manner is an essential step in biomechanical analysis of human motion. With advance of computer vision, and reduction in cost of electronic components, building a customized computer-vision based measurement device becomes possible. In the paper a novel structured light pattern for 3D structured light scanner is proposed. During development, accuracy and robustness of the proposed system were tested on artificial objects with known surface configurations, after which measurements were performed on human subjects. Simultaneous measurements with standard structured light pattern were achieved and obtained results compared. Volumetric parameters of both artificial object and human body segment obtained by 3D scanning were compared to the immersion method and were found to be in a good agreement and were used for segment mass estimation. Obtained results are presented and analyzed, and conclusions about system performance with possible improvements are discussed.     

Sterols and triterpene diols in olive oil as indicators of variety and degree of ripening

Sterols and triterpene diols in olive oil as indicators of variety and degree of ripening derived from three olive varieties and produced at three different harvesting periods were studied. In order to test the stability of the proposed indicators, oils obtained were stored for 12 months at three different temperatures. Thirty-six samples in total were subjected to GC analysis and results were processed by multivariate chemometric methods (MANOVA, PCA, and SLDA). Campesterol, β-sitosterol, Δ⁷-campesterol/Δ^5,24-stigmastadienol, clerosterol, uvaol, and campestanol/Δ⁷-avenasterol were established as the indicators of variety of fresh oils, while when stored oils were included in the model, the final three compounds were substituted by 24-methylene-cholesterol/stigmasterol. The most important variables for differentiating fresh oils according to degree of ripening were Δ⁷-campesterol/β-sitosterol, uvaol/stigmasterol, clerosterol/Δ⁵-avenasterol and sitostanol/uvaol, while stored oils were differentiated by campestanol/stigmasterol, erythrodiol, stigmasterol/Δ⁷-campesterol, Δ⁵-avenasterol, 24-methylene-cholesterol/β-sitosterol and 24-methylene-cholesterol. Results demonstrated that sterols and triterpene diols can be used as indicators of variety and degree of ripening among virgin olive oils.     

Microwave-assisted synthesis of carboxymethylcellulose – based polymeric surfactants

Summary Carboxymethylcellulose (CMC, DS_CM = 1) was partially hydrophobized in order to prepare polymeric surfactants by the transesterification reaction using the methyl ester of the fatty acid complex of rapeseed oil (MERO). The chemical modification was performed in different reaction media (i) DMF/TSA and (ii) H₂O/DMF with and without K₂CO₃ as catalyst, at various reaction conditions and using microwave radiation with controlled power as heating source. The obtained MERO-hydrophobized CMC (MH-CMC) comprising mixed fatty acyl esters were characterized by FT-IR and NMR spectroscopic techniques, which indicated a very low degree of esterification (DS < 0.1). The derivatives showed, in spite of moderate surface tension-lowering effects, excellent emulsifying activity for ‘oil in water’ type emulsions as well as good performance properties including washing power and antiredeposition efficiency. The results suggested that surface-active MH-CMC derivatives can be prepared under microwave heating at reaction times in the range of several minutes, what is a great advantage in comparison to transesterification reactions lasting up to 6 h at conventional heating. The novel CMC esters represent biodegradable polymeric surfactants with potential applications in manufacture of consumer products and in industrial processes.     

Fresh from the Ornamental Garden: Hips of Selected Rose Cultivars Rich in Phytonutrients

Morphological parameters (size, weight, color), the content of sugars, organic acids, lycopene, β‐carotene, and phenolics were determined in hips of Rosa canina (RCA), Rosa sweginzowii (RSW), Rosa rugosa (RUG), and selected ornamental Rosa cultivars Fru Dagmar Hastrup (FDH), Repandia (REP), Veilchenblau (RVB), Aloha (RAL), Bonica (BON), and Golden Gate (RGG). Although traditionally used RCA hips contained the highest amount of cyanidin‐3‐glucoside (83 μg/g DW) and were the reddest (h° = 17.5), they did not stand out in other analyzed parameters. RGG climber had the biggest hips (8.86 g), which also contained highest sugar levels (50.9 g/100 g DW). RAL stood out as the cultivar rich in organic acids (33.9 g/100 g DW), mainly because of high quinic acid content (17.6 g/100g DW). FDH and RSW hips were characterized by particularly high ascorbic acid levels (4325 mg/100 g DW and 4711 mg/100 g DW). Other ornamental cultivars contained low amounts of ascorbic acid compared to the analyzed species. The phenolic profile was species/cultivars‐specific. The greatest diversity of phenolic compounds was detected in RUG and FDH hips (55 and 54 different tentatively identified compounds with HPLC/MS). Flavanols represented the main phenolic class in most of the investigated species/cultivars and RGG hips contained the highest amount of catechin and proanthocyandin derivatives (15855 μg/g DW). Altogether RAL hips contained the highest quantity of phenolics (44746 μg/g DW) mainly due to high levels of hydrolysable tannins compared to other species/cultivars. Although small, hips of BON and REP were most abundant regarding β‐carotene and lycopene content, respectively.     

Kinase Signaling in Apoptosis Induced by Saturated Fatty Acids in Pancreatic β-Cells

Pancreatic β-cell failure and death is considered to be one of the main factors responsible for type 2 diabetes. It is caused by, in addition to hyperglycemia, chronic exposure to increased concentrations of fatty acids, mainly saturated fatty acids. Molecular mechanisms of apoptosis induction by saturated fatty acids in β-cells are not completely clear. It has been proposed that kinase signaling could be involved, particularly, c-Jun N-terminal kinase (JNK), protein kinase C (PKC), p38 mitogen-activated protein kinase (p38 MAPK), extracellular signal-regulated kinase (ERK), and Akt kinases and their pathways. In this review, we discuss these kinases and their signaling pathways with respect to their possible role in apoptosis induction by saturated fatty acids in pancreatic β-cells.     

p38 MAPK Is Activated but Does Not Play a Key Role during Apoptosis Induction by Saturated Fatty Acid in Human Pancreatic β-Cells

Saturated stearic acid (SA) induces apoptosis in the human pancreatic β-cells NES2Y. However, the molecular mechanisms involved are unclear. We showed that apoptosis-inducing concentrations of SA activate the p38 MAPK signaling pathway in these cells. Therefore, we tested the role of p38 MAPK signaling pathway activation in apoptosis induction by SA in NES2Y cells. Crosstalk between p38 MAPK pathway activation and accompanying ERK pathway inhibition after SA application was also tested. The inhibition of p38 MAPK expression by siRNA silencing resulted in a decrease in MAPKAPK-2 activation after SA application, but it had no significant effect on cell viability or the level of phosphorylated ERK pathway members. The inhibition of p38 MAPK activity by the specific inhibitor SB202190 resulted in inhibition of MAPKAPK-2 activation and noticeable activation of ERK pathway members after SA treatment but in no significant effect on cell viability. p38 MAPK overexpression by plasmid transfection produced an increase in MAPKAPK-2 activation after SA exposure but no significant influence on cell viability or ERK pathway activation. The activation of p38 MAPK by the specific activator anisomycin resulted in significant activation of MAPKAPK-2. Concerning the effect on cell viability, application of the activator led to apoptosis induction similar to application of SA (PARP cleavage and caspase-7, -8, and -9 activation) and in inhibition of ERK pathway members. We demonstrated that apoptosis-inducing concentrations of SA activate the p38 MAPK signaling pathway and that this activation could be involved in apoptosis induction by SA in the human pancreatic β-cells NES2Y. However, this involvement does not seem to play a key role. Crosstalk between p38 MAPK pathway activation and ERK pathway inhibition in NES2Y cells seems likely. Thus, the ERK pathway inhibition by p38 MAPK activation does not also seem to be essential for SA-induced apoptosis.