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Advances continue to be made in tumor immunology and in strategies to integrate the growing number of bioimmunotherapeutic molecules into the treatment of ovarian cancer, as well as other malignancies. Extensive studies have provided support for antigen-driven T-cell activation in vivo. The number of known tumor antigen epitopes is expanding, although advances in this area remain behind that of melanoma. Evidence suggests that the tumor environment is contributing to a state of in vivo immunosuppression; however, in vitro experiments and laboratory correlative studies also show that immune suppressor activity might be reversible. These findings could lead to new approaches, such as the use of antibodies or cytokines to overcome the immunosuppressive effects, in addition to the more established surgical and chemotherapeutic debulking. Both prophylactic and therapeutic bioimmunotherapeutic strategies require pharmacodynamic and immunologic end points that can guide each phase in the development of an effective approach. Review of systemic and intraperitoneal (IP) immunotherapy trials of interferon (IFN) α, IFNγ, and interleukin 2 (IL2), as well as newer agents such as IL12 and Flt3 ligand, overall continues to offer promise of a role for bioimmunotherapy in the treatment of ovarian cancer. Future developments lie in the improved target specificity of activated cells and cell-surface-binding molecules and in a systematic plan for combining chemotherapy with cytokines, growth factors, and polyvalent vaccines that are based on the in vivo dynamics of each agent. Another totally different approach, which could set a new paradigm, might be to target cells from the inflammatory immune system, which could contribute to tumor growth, invasion, and metastasis. [ABSTRACT FROM AUTHOR]

Intraperitoneal (IP) chemotherapy for advanced ovarian cancer improves both overall and disease-free survival. In this chapter, we compare the effectiveness of intravenous (IV) to IP chemotherapy. The evidence suggests an improvement in survival if some of the chemotherapy is administered via the IP route. The adverse events principally relate to the presence of a peritoneal catheter, including pain, catheter blockage, gastrointestinal effects, and infection. A systematic search identified eight relevant randomized trials studying 1,819 women receiving primary treatment for ovarian cancer. Women were less likely to die if they received an IP component to the chemotherapy (hazard ratio = 0.80; 95% confidence interval [CI] = 0.71-0.90). Administering a component of chemotherapy by the IP route also prolongs the disease-free interval (0.79; 0.69-0.90) by almost 9 mo and increases complete response rates. There may, however, be greater pain, fever, and gastrointestinal toxicity, but less ototoxicity, using the IP route. [ABSTRACT FROM AUTHOR]

The mathematical modeling concepts developed by Robert Dedrick and his colleagues, and subsequent preclinical evaluation, provided a strong framework upon which to build a clinical investigative program examining intraperitoneal (IP) chemotherapy as a management approach in advanced ovarian cancer. These investigative efforts suggested the type of antineoplastic agents that should be explored, the patient populations more likely to benefit, and the limitations and potential toxicities of this novel strategy. [ABSTRACT FROM AUTHOR]

To date, the accomplishment in the area of regional treatment of ovarian cancer has been a major advance in the management of this difficult malignancy. What began as a hypothesis, based on a theoretical mathematical model, has been translated into a 67-mo median survival for women with small-volume residual advanced ovarian cancer (1). The three major randomized clinical trials on ovarian cancer are detailed in this chapter. The methodology and outcomes, as well as a critique of their design, are presented. Outcomes of these trials to date are described. [ABSTRACT FROM AUTHOR]

Although striking evidence exists that argues for the usefulness of hyperthermic intraperitoneal chemotherapy (HIPEC) for the treatment of peritoneal carcinomatosis (PC), many aspects of this therapy have yet to be standardized. As interest in this modality increases, there are several avenues of research to be explored. How important is the cytoreductive effort, the temperature elevation increment, and the length of time for the hyperthermic perfusion? We review what is known and what may be explored in the near future. [ABSTRACT FROM AUTHOR]

Hyperthermic intraperitoneal chemotherapy (HIPEC) was first delivered to a human in 1979 by Dr. John Spratt at the University of Louisville when he treated a male patient with pseudomyxoma peritonei (1). In collaboration with other researchers, he developed a delivery system using a "closed" technique, with both the fascia and skin closed. Since that time, there has been increasing interest around the world in the delivery of HIPEC. The most widely used methods have involved perioperative perfusion of chemotherapy in heated perfusate performed at the time of open laparotomy (see the following sections), but delivery of HIPEC has also been reported with laparoscopic placement of inflow and outflow tubing (2) and regional (3) and whole-body hyperthermia (4). Hyperthermic intraperitoneal chemotherapy requires an organized team within the operating room who all understand their roles. The anesthesiologist manages the cooling of the patient's core temperature before the hyperthermic perfusion and monitors the patient's vital parameters, particularly the core temperature, during the perfusion. The perfusionist, often recruited from cardiac surgery because of experience with the techniques of cardiopulmonary bypass, operates the heat exchange pump and equipment for the perfusion. Although it is everyone's responsibility, the scrub technicians and circulating nurses are charged with the specific duty of ensuring proper adherence to operating room protocol for the use of hazardous agents. The two main techniques for hyperthermic IP perfusion are "open," where the incision is open during the HIPEC, and "closed" where the abdominal skin and/or fascia are closed. Both basic methods have been extensively utilized, with many individual variations. In this chapter, the most widely used open technique, the "Coliseum," and the closed technique will be described and discusse [ABSTRACT FROM AUTHOR]

Research into the incorporation of hyperthermic intraperitoneal chemotherapy into treatment regimens for women with ovarian carcinoma has lagged behind that of other cancers causing peritoneal carcinomatosis despite the fact that ovarian cancer represents an excellent target for this modality of treatment. This chapter reviews experience with this technique from around the world, with the exception of France, and discusses future developments. [ABSTRACT FROM AUTHOR]

Epithelial ovarian cancers (EOC) represent 80%-90% of all ovarian malignancies, and they are the most common cause of death for all gynecological tumors in the Western world (1). The majority of patients have an advanced Federation of Gynecology and Obstetrics (FIGO) stage III or IV disease at presentation, but the disease is often confined to the peritoneal cavity (2). Current standard treatments of these patients consist of initial cytoreductive surgery (CRS) to <1-cm residual nodules, followed by combination systemic chemotherapy with a taxane and platinum analogue, either carboplatin or cisplatin. Our experience in France with a phase II prospective single-center study shows that the population is inhomogeneous, and >58% of patients underwent CRS and HIPEC after >2 prior recurrences and >2 laparotomies. Because of these multiple recurrences before inclusion, it was not possible to calculate the progression-free interval (PFI). In the literature, most of the series evaluating CRS alone are dedicated to secondary CRS, meaning that the patients are experiencing their first recurrence. The only feasible comparison between secondary CRS alone and this study could be on the completeness of cytoreduction, which appears as the most important prognostic factor. The present phase II study clearly underlines that combined salvage therapy can achieve long-term survival in some patients with second, third, or fourth locoregional recurrence from ovarian cancer. [ABSTRACT FROM AUTHOR]

Second to liver, the peritoneum is the most frequent site of metastases in colorectal cancer. In approximately 10% of patients, peritoneal carcinomatosis (PC) is already present at the time of initial diagnosis (1). PC is found in 30% of patients with recurrent colorectal cancer, either as part of more generalized metastases or as the only site. PC is the only site of tumor activity in 40% of cases (2). This means that approximately 8% of all colorectal cancer patients will have PC as their only site of cancer activity at some stage of their disease. PC is generally considered to represent distant metastasis and is staged as M1. Accordingly, until recently, treatment has been limited to palliative surgery, such as enterostomy or bypass to relieve obstruction, and systemic chemotherapy. There are few studies specifically reporting on the outcome of this approach in PC (3). Most studies on chemotherapy in metastatic colorectal cancer include all sites of metastases, with a dominance of liver metastases. Although some reports suggest that colorectal cancers recurring as PC are less likely to respond to systemic chemotherapy, there is little evidence for this. However, there is no doubt that PC patients have a shorter life expectancy than do patients with other metastatic sites, such as liver. This is probably explained by the difficulty in visualizing PC on scans, leading to relatively late diagnosis and the early development of bowel obstruction, even on relatively small tumor volumes. In our series at the Netherlands Cancer Institute, the diagnosis of PC in recurrent cases was made in 80% of patients during laparotomy for bowel obstruction. As a result, many patients will have either a (high output) ileostomy or a relative obstruction, making optimal chemotherapeutic treatment more difficult. In this circumstance, median survival is reported to be between 4 mo and 12 mo (4). [ABSTRACT FROM AUTHOR]

Cytoreductive surgery (CRS) + hyperthermic intraperitoneal chemotherapy (HIPEC) has had a significant impact in the management of peritoneal surface malignancies of nongynecologic origin. It has improved the quality and quantity of life for these patients. Evidence of improved median survival has been observed independent of the origin of the carcinomatosis, and this treatment paradigm resulted in measurable 5-yr survival in diseases where it did not exist before the use of CRS + HIPEC. [ABSTRACT FROM AUTHOR]

Cancer ranks second only to heart disease as the greatest cause of mortality in the United States. Despite significant strides in diagnosis and therapeutics, clinical treatment of metastatic cancer still yields a poor prognosis. Basic science research is increasing our knowledge of the mechanisms by which chemotherapeutic and hyperthermic modalities exert their antitumor activity. Herein, we describe the current state of knowledge of these treatment modalities and the basic science behind their clinical usefulness. Moreover, we identify gaps in our understanding of the basic science of these treatments. Basic science is primed to exert a substantial role in extending our therapeutic options through the clarification of current therapeutic mechanisms, as well as the generation of novel treatments. [ABSTRACT FROM AUTHOR]

Ideally, the intraperitoneal chemotherapy (IP) delivery device is placed at the time of the original diagnostic procedure, when an optimal surgical resection can be completed. The patient, who is appropriately counseled before surgery about her risk of cancer and the treatment options available, should have an IP device placed at the time of surgical resection of the presumed ovarian or primary peritoneal cancer. The pathologic diagnosis and stage is not completely understood in that setting, but good clinical judgment can identify an appropriate candidate for IP chemotherapy. It is safer to place the device and remove it unused at the bedside later, than to forego placement and have to reoperate to place the device at a second procedure. The second procedure to place an IP catheter is an important barrier to initiating IP chemotherapy, and also delays proper treatment. [ABSTRACT FROM AUTHOR]

We report the study of the self-diffusion coefficient for strongly interacting polystyrene latex particles in a water solution, where aggregation processes are present. The reported data, obtained by measuring the contribution in the intensity-intensity correlation function of the occupation fluctuation number of particles in the scattering volume, agree with the current models of kinetic growth for random aggregation. [ABSTRACT FROM AUTHOR]

Divalent (2-ethyl hexyl) sulfosuccinate surfactant is used to form water in oil aggregates. By increasing the water content pronounced structural changes are observed. At low water content spherical droplets are formed. By increasing the water content, cylindrical aggregates are formed. The maximum amount of water solubilized using divalent surfactants is relatively low (the limit value of the ratio of water over AOT concentration w is less than 7, using divalent surfactants, and is equal to 60 using sodium AOT). At higher water content a phase transition is observed with two isotropic phases, with the lower phase containing mainly the surfactant. [ABSTRACT FROM AUTHOR]

We have investigated, by means of radiowave dielectric spectroscopy measurements, the ripple phase of two different phospholipid — water mixtures (DPPC and DMPC), each of them containing different amounts of DPPE or DMPE, respectively, up to 7% wt/wt of total lipid. — Addition of DPPE or DMPE to the phospholipid aqueous systems should reduce the effective head group area and, hence, the orientational head group dipole correlation. The results, showing a marked damping of the dielectric increment at the pretransition in relation to the DPPE or DMPE concentration, provide further evidence that the anomalous polarization observed in these systems at the pretransition temperature must be attributed to the bilayer ripple modulation. [ABSTRACT FROM AUTHOR]

The passive electrical properties of human lymphocyte membranes incubated with different gangliosides have been measured by means of radiowave dielectric spectroscopy in the frequency range where the Maxwell-Wagner effect occurs. — The alterations of the membrane structure and functionality reflect in an increase of the membrane conductivity σs and membrane permittivity εs, depending on the chemical composition of the ganglioside employed. The possible relation to the structural changes of the cytoplasmatic membrane are briefly discussed. [ABSTRACT FROM AUTHOR]

The bilayer hydrophobic thickness l is estimated from the 2H-NMR spectra of acyl chain perdeuteriated membrane phospholipids. Values obtained from individual quadrupolar splittings and those from the first moment of a powder spectrum are in close agreement. In the fluid (La) phase, the thermal variation of dimyristoylphosphatidylcholine (DMPC), dimyristoylphosphatidic acid (DMPA) at pH 4.2 and 8.2, and DMPC: cholesterol (7:3) bilayer thicknesses are compared; 30% cholesterol increases the thickness of dMPC by approximately 4-5 Å, whatever the temperature. DMPC and DMPA (whatever the pH) have the same hydrophobic thickness near their respective Tc, the gel-to-fluid phase transition temperature, and display a very similar l decrease when increasing the temperature. However, at high temperatures (60°C) DMPC is thinner than DMPA by approximately 1 Å. Steric, electrostatic, and temperature constraints are therefore seen to modulate the biomembrane hydrophobic thickness , as easily estimated by 2H-NMR. [ABSTRACT FROM AUTHOR]

The formation of lyotropic mesophases in systems of tetradecyldimethylaminoxide/water/aliphatic alcohol was examined in dependence on alcohol concentration and alcohol chain length (heptanol, octanol, nonanol, decanol). The ternary phase diagrams were established. The following lyotropic phases were detected by microscopic texture observation: hexagonal phase (H), lamellar phase (La), rodlike nematic phase (NC), and disklike nematic phase (ND). The positions of the corresponding regions in the phase diagrams were determined. In particular, the NC- and ND-phase were of special interest. — Lyotropic-cholesteric phases were induced in the lyotropic-nematic phase region by adding optically active components such as cholesterol, tartaric acid, lithocholic acid. When subjected to the influence of a magnetic field, these cholesteric phases show the socalled spaghetti-like texture. The textures have been used for determining the pitch length. A linear relation between pitch length and concentration of the optically active components was established. [ABSTRACT FROM AUTHOR]

Rod formation is primarily governed by the characteristic Gibbs free energy of rod formation, ΔGrod. Geometrically, a rod-shaped micelle consists of a central cylindrical part of hydrocarbon radius rc and of more or less hemispherical parts at the ends of hydrocarbon radius rs. To smooth out the transition region between the spherical part of an endcap and the cylindrical part a catenoid is introduced. The model includes hydrophobic, electrostatic, and steric interactions, and allows direct adsorption of counterions to the micelle surface. It is used to calculate the optimal radius of the cylindrical part and to determine the according equilibrium configuration of the endcaps. The theoretical results are compared with empirical data for cetylpyridinium salts. Direct counterion adsorption is found to amount to about 50%. A strong steric influence on counterion adsorption is given. [ABSTRACT FROM AUTHOR]

The effect of methanol, ethanol, and 1-propanol on the critical micelle concentration (CMC) of several surfactant aqueous solutions has been studied in the 10-40°C temperature range by surface tension and conductivity measurements. Experimental parameters such as the standard free energy, enthalpy and entropy of micellization weere also determined. — The results show that on increasing alcohol concentration the CMC first reaches a minimum at an intermediate cosolvent mole fraction x2 = x*2 typical for each alcohol, and then increases with increasing x2. The value of x*2 is close to that at which structural changes in the mixtures occur as inreferred from compressibility, UV, IR absorption spectra, and neutron and x-ray scattering measurements. — The present experiments support the assumption that the dominant mechanism by which 1-alcohols affect the micellization process is through their effect on the structure of solvent. It is suggested that the same conclusion could be valid for a number of other systems of biological and chemical interest. [ABSTRACT FROM AUTHOR]

The concentration dependence of the infrared spectra of CCl4 solutions of AOT [bis(2-ethylhexyl)sodium sulfosuccinate] has been determined in a concentration range (0-1.6 mM) encompassing the critical micelle concentration (CMC ≃ 0.2 mM). — Effects detected on the molar extinction coefficients of the bands due to C-H stretching vibrations can be used as indicators of micelle formation. — The same spectroscopic technique has also been used to investigate the structure of water in oil microemulsion. The interaction of water with reversed micelles of AOT has been studied as a function of the ratio W = [H2O]/[AOT] in the range 0-12 by using the absorption band due to O-H stretching mode, in the 3800-3000 cm−1 range, and the absorption band in the range 1700-1500 cm−1, arising from the H-O-H bending vibration. Our results indicate that at low W values (W < ∼4) the water in micellar core is structurally and motionally different from unperturbed bulk water. On increasing W, water displays more marked "bulk" properties, and the absorption bands approach that of bulk water. [ABSTRACT FROM AUTHOR]

The model for multicomponent nonideal mixed micelles used via the regular solution approximation allows accounting for the critical micelle (CMC) of binary or ternary mixtures obtained with nΦCm (anionic surfactant), TTAB (cationic surfactant), and OP(EO)8 (nonionic surfactant). The anionic/cationic interaction is much higher than the ionic/nonionic interactions; this is probably due to the high electrostatic attraction between molecules which have opposite charges. We have found that anionic/cationic interaction appears to depend very slightly on the anionic surfactant structure, while anionic/nonionic interaction increases with the length of the alkyl chain of the anionic surfactant, but does not depend significantly on the position of the polar and head branching. — The introduction in the model of the pair interaction parameters, determined from the CMC of the binary mixtures, gives valuable predictions for the CMC and for the micelle compositions of the ternary mixtures. CMC of the ternary mixture are lower than the CMC of each component of the mixture. Contrary to that which is expected for an ideal mixing, the mixed micelles are principally composed of ionic surfactant molecules. Our results seem to show that these behaviors could depend slightly on the position of the polar head branching and on the length of the alkyl chain of the anionic surfactant. [ABSTRACT FROM AUTHOR]

Conductivities of the AOT and nonionic C12E5 systems are reported. A preculiarity of the AOT system is the possibility to prepare w/o microemulsions with more than 50 wt% of water, which show, however, a low conductivity. In contrast, a nonionic system with comparable amounts of water and oil displays a conductivity several orders of magnitude larger. Upon addition of salt the conductivity pattern of the AOT system resembles that of a nonionic with opposite temperature dependence. [ABSTRACT FROM AUTHOR]

We report a dynamic (QLS) and static (SLS) light scattering and small-angle neutron scattering (SANS) investigation of lecithin reverse micellar solutions with novel polymer-like properties. We present evidence for a water-induced transition from small colloid-like to giant polymer-like cylindrical aggregates. Under suitable conditions, we can determine the overall dimension, the flexibility, and the local cylindrical structure of these reverse micelles using SLS and SANS. This permits us to directly confirm the existing structural model and verify the postulated analogy between the structural properties of polymer chains and lecithin reverse micelles. [ABSTRACT FROM AUTHOR]

The phase behavior of ternary mixtures of water, hydrocarbons, and nonionic amphiphiles is, by now, well known. In this paper the effect of replacing water by formamide is studied. This polar protic solvent reduces the hydrophobic effect and, thereby, the repulsive interactions with surfactant tails. The result is a higher mutual solubility of formamide and surfactant, a weaker adsorption at the internal interface and, hence, a lower solubilization capacity of the amphiphile. The reduced amphilphilic strength of surfactants in formamide corresponds to Ci-4E in aqueous systems. As with aqueous systems the present mixtures form microstructures, namely oil-droplets in formamide and formaide-droplets in oil. For equal volumes of formamide and oil, small-angle neutron scattering (SANS) spectra indicate the existence of bicontinuous structures. [ABSTRACT FROM AUTHOR]

FT-IR spectra in the hydroxyl region in reversed micelles where the sodium counterions of the surfactant Aerosol-OT have been replaced by Ca2+ and Zn2+ ions are presented. The IR spectra, taken as a function of the molar ratio R = [H2O]/[surfactant], are analzyed in the framework of a twostate model for the water molecules in which the O-H vibration can be split into two contributions: one originated by the water "tightly-bonded" to the surfactant ions, and the other induced by the "bulk" water of the micellar water pool. We also evaluate the percentage a(R) of the bond water in the micellar growth process. Furthermore, an explanation of the O-H stretching band features is suggested by comparison between our spectra and those simulated through an MD "experiment". [ABSTRACT FROM AUTHOR]

Lecithin/isooctane/water gel is investigated by means of different experimental techniques, namely, depolarized light scattering, ultrasonic and dielectric measurements. Pure isooctane and lecithin/isooctane solution are also tested for comparison. A relaxation process, taking place in the 10−13 s time scale was revealed from the light-scattering experiment, both in the gel and in the solution. This is attributed to the reorientational relaxation of the solvent that keeps its bulk properties. The comparison between the activation enthalpies for the detected process in the gel and in the solution, together with the behavior of the relaxation times vs frequency showed the existence of some influence of the entangled network on the isooctane dynamics. Data from ultrasonic measurements show the existence of the same relaxation process, both in the gel and in the solution, with a relaxed value very near to the one obtained for pure isooctane. The observed dynamics were interpreted as due to the existence of the same elementary microspheres of lecithin in the bulk of the solvent in both systems. The relaxation phenomenon revealed by the dielectric data was analyzed in the frame of a Cole-Cole phenomenological law and associated to the role played by water molecules on lecithin reorientation. The temperature dependence of the observed phenomenon is in agreement with the existence of an entangled polymeric-network. [ABSTRACT FROM AUTHOR]

Alkyl monoglycosides and polyglycosides (APG) are characterized in terms of their interfacial properties which exhibit a dependence on alkyl chain length and degree of polymerization. A comparison is drawn to other nonionic and anionic surfactants. In hard water, clouding phenomena are observed for C8/10 and C12/14 APG. The critical micelle concentrations (CMC) of the alkylglycosides are similar to those of other nonionic surfactants and show a decrease with increasin galkyl chain length. The degree of polymeriization has only a minor influence on the CMC. Above the CMC, alkylglycosides exhibit very low interfacial tensions against mineral oil compared to C12/14 fatty alcohol sulfate (C12/14 FAS). In contrast to C12/14 FAS and C12/14 fatty alcohol hexaglycol ether, respectively, C12/14 APG shows remarakbly high dynamic surface tensions even at a concentration far above the CMC. For mixtures of C12/14 APG and C12/14 FAS the static surface tensions and the CMC lie close to those of C12/14 APG, whereas the dynamic surface tension behavior is dominated by the anionic surfactant. [ABSTRACT FROM AUTHOR]

The preparation of oriented protein samples is an attractive goal, e.g., to gain more detailed information from spectroscopic experiments. Our approach towards this aim was to prepare monolayers of phospholipids at the air-water interface and to incorporate the proteins into these ordered structures. Subsequently, we used the Langmuir-Boldgett (LB) transfer technique to obtain samples of oriented proteins on solid supports. — Incorporation was achieved by spreading the proteins from a detergent solution onto a prespread lipid monolayer on the water surface. We characterized successful incorporation by in situ fluoresence microscopy and by electron microscopy, and investigated the topology of transferred monolayers. — Our results show that the choice of the lipid matrix is pivotal. We present an optimized lipid matrix system that facilitates protein incorporation, while enabling LB transfer at the same time. — Fluorescence microscopic investigations revealed that the lateral phase structure of the lipid films remains qualitatively unaffected by the reconstitution, with the proteins incorporated into the fluid phases. Quantitative evaluations of the protein content of the thin film samples indicated that ∼15% of the proteins spread were incorporated, whereas evaluation of the additional area of incorporation (of protein and detergent) showed that a substantial amount of detergent was incorporated as well. [ABSTRACT FROM AUTHOR]

Electronic speckle pattern interferometry (ESPI) can detect micro displacements and deformation of optically rough surfaces. — Experiments have been performed on pure liquid surfaces and Langmuir films at the airwater interface to determine whether ESPI can be implemented to study liquid surface properties. — Mechanically induced resonant modes of liquid surfaces have been visualized as interference patterns similar to Chladni figures. Oscillation amplitudes on the order of a few microns have also been measured. — The resonance frequency depends only slightly on surface tension and surface pressure, while there is greater correlation between vibration amplitude and the characteristics of the liquid surface. — On the basis of these preliminary results it may be possible to use this technique to detect short wavelength oscillations (<1 mm) and to measure the damping of capillary ripples to obtain the viscoelastic parameters of liquid surfaces. [ABSTRACT FROM AUTHOR]

The adsorption behaviour of a homologous series of amphiphilic hemicyanines is studied at the air-water interface. The dyes exhibit an unusual, marked odd-even effect with respect to the standard free energy of adsorption and the minimum surface area demand. The reasons for such strong, hitherto unknown odd-even effect is not yet clear. [ABSTRACT FROM AUTHOR]

Nitronylnitroxides are promising materials for the preparation of unusual magnetic systems, particularly when coordinated with transition metal ions. In this work mono- and multilayers of the amphiphilic radical 2-tridecyl-4,4,5,5-tetramethyl-imidazolidine-1-oxyl-3-oxide radical were characterized from its spreading isotherms and by optical and ESR spectroscopy. The time stability of the films was also studied. [ABSTRACT FROM AUTHOR]

The following two-dimensional binary systems at the W/A interface are studied: stearic acid (SA)-polymethylmethacrylate (PMMA), stearylamine (SAm)-PMMA, SA-valinomycin (VAI), SAm-VAL, methylstearate (MS)-VAL. — The behavior of area, surface compressional moduli, and overall collapse pressure as a function of molar ratios of components shows: i) SA and SAm are compatible with PMMA if the pH of support allows their ionization; ii) SA and SAm are incompatible with VAL at any pH value of the support studied. — The different behavior is attributed to the impossibility of interactions between polar groups of VAL and ionizable groups of the other component. The bidimensional distribution of the VAL is confirmed by transfer of K+ from subphase to monolayers, proved by ATR-FTIR experiments on mono and plurilayers of VAL. — The polar groups are therefore oriented toward the inner molecular cavity of VAL. — The study extended to the MS-VAL system shows compatibility between components with prevalent repulsive interaction between the two components. [ABSTRACT FROM AUTHOR]

We have studied monolayers of a dye containing hydrophobic moieties at the air/water interface and in LB films. In particular, the aims of the present study were to characterize the interfacial behavior of the alkylsubstituted cyanine dye, (N,N′-tetrahexadecylcyanine iodide) to investigate the surface miscibility of the cyanine dye with the matrix molecule (dihexadecylphosphate), and to correlate the results obtained at the air/water interface with the data collected on transferred layers of the same system. For these purposes, mixtures with different molar ratios of matrix and dye were prepared and their interfacial distribution and orientation were studied, both at the air/water interface, and in multilayers transferred on solid substrates. The Monolayers at the air/water interface were studied by measuring surface pressure-area and reflection at constant area or at constant wavelength, whereas absorption spectra were performed on the transferred layer system. [ABSTRACT FROM AUTHOR]