l-type resonance in an overtone band. The 2ν4 spectrum of nitrogen trifluoride

l-type resonance in an overtone band is discussed. It is shown that if the anharmonic constant g_ll is small the resonance effect may be as large as or even larger than, the corresponding fundamental. Intensity perturbation may be manifested by the appearance of forbidden lines. This analysis is applied to the high frequency portion of the 2ν₄ spectrum of NF₃ and band constants are obtained.     

Lectures on renormalization and asymptotic safety

A short introduction is given on the functional renormalization group method, putting emphasis on its nonperturbative aspects. The method enables to find nontrivial fixed points in quantum field theoretic models which make them free from divergences and leads to the concept of asymptotic safety. It can be considered as a generalization of the asymptotic freedom which plays a key role in the perturbative renormalization. We summarize and give a short discussion of some important models, which are asymptotically safe such as the Gross–Neveu model, the nonlinear σ$\sigma$ model, the sine–Gordon model, and we consider the model of quantum Einstein gravity which seems to show asymptotic safety, too. We also give a detailed analysis of infrared behavior of such scalar models where a spontaneous symmetry breaking takes place. The deep infrared behavior of the broken phase cannot be treated within the framework of perturbative calculations. We demonstrate that there exists an infrared fixed point in the broken phase which creates a new scaling regime there, however its structure is hidden by the singularity of the renormalization group equations. The theory spaces of these models show several similar properties, namely the models have the same phase and fixed point structure. The quantum Einstein gravity also exhibits similarities when considering the global aspects of its theory space since the appearing two phases there show analogies with the symmetric and the broken phases of the scalar models. These results be nicely uncovered by the functional renormalization group method.     

Thermally Reversible Self‐Assembly of Nanoparticles via Polymer Crystallization

The directed self‐assembly of gold nanoparticles through the crystallization of surface‐grafted polyethylene oxide (PEO) in ethanol–water mixtures is described. This process is fully reversible and tunable through either the size of the core or the polymeric coating. Characterization by X‐ray scattering and electron microscopy of the self‐assembled structures reveals order at the nanoscale, typically not the case for thermoresponsive gold nanoparticles coated with lower or upper critical solution temperature polymers. A further novelty is the result of selective binding of calcium ions to the PEO in the fluid state: a reversible thermoresponsive transition become irreversible.

     

Determination of the size of quantum dots by fluorescence spectroscopy

There has been a lack of quick, simple and reliable methods for determination of nanoparticle size. An investigation of the size of hydrophobic (CdSe) and hydrophilic (CdSe/ZnS) quantum dots was performed by using the maximum position of the corresponding fluorescence spectrum. It has been found that fluorescence spectroscopy is a simple and reliable methodology to estimate the size of both quantum dot types. For a given solution, the homogeneity of the size of quantum dots is correlated to the relationship between the fluorescence maximum position (FMP) and the quantum dot size. This methodology can be extended to the other fluorescent nanoparticles. The employment of evolving factor analysis and multivariate curve resolution-alternating least squares for decomposition of the series of quantum dots fluorescence spectra recorded by a specific measuring procedure reveals the number of quantum dot fractions having different diameters. The size of the quantum dots in a particular group is defined by the FMP of the corresponding component in the decomposed spectrum. These results show that a combination of the fluorescence and appropriate statistical method for decomposition of the emission spectra of nanoparticles may be a quick and trusted method for the screening of the inhomogeneity of their solution.     

Effect of polyelectrolytes and polyelectrolyte mixtures on the electrokinetic potential of dispersed particles. 2. Electrokinetic potential of silica particles in electrolyte, polyelectrolyte and polyelectrolyte mixtures solutions

The effect pH, ionic strength (KCl concentration), weakly and medium charged anionic and cationic polyelectrolytes (PEs) as well as their binary mixtures on the electrokinetic potential of silica particles as a function of the polyelectrolyte/mixture dose, its composition, charge density (CD) of the PE, and way of adding the polymers to the suspension has been studied. It has been shown that addition of increasing amount of anionic PEs increases the absolute value of the negative zeta-potential of particles at pH > pH isoelectric point (IEP = 2.5); this increase is stronger the charge density of the polyelectrolyte is higher. Adsorption of cationic polyelectrolytes at these pH values gives a significant decrease in the negative ζ-potential and overcharging the particles; changes in the ζ-potential are more pronounced for PE samples with higher CD. In mixtures of cationic and anionic PE at pH > pHIEP, the ζ-potential of particles is determined by the adsorbed amount of the anionic polymer independently of the CD of PEs, the mixture composition and the sequence of addition of the mixture components. Unexpectedly, the ζ-potential of silica at pH = 2.1, i.e. < pHIEP, turned out to be positive in the presence of both anionic PE and cationic + anionic PE mixtures. This is explained by formation (and adsorption onto positively charged silica surface) of pseudo-cationic PEs from anionic ones due to transfer of protons from the solution to the amino-group of the anionic polymer. Considerations about the role of coulombic and non-coulombic forces in the mechanism of PE adsorption are presented.     

Comparison of deconvoluted plasma DSC curves on patients with solid tumors

Melting of crystalline compounds inside the nanopores of open-morphology porous systems was studied on a model system, consisted of 1-octadecene and silica gels with different pore sizes, by means of thermogravimetry, differential scanning calorimetry and powder X-ray diffraction. The parameters of silica gels porous structure (surface area, pore size and volume) were calculated using N₂ adsorption data. To describe the experimental results, a new thermodynamic model of crystallites melting inside the nanopores of irregular shape was established. This model allows an analytical prediction for the shift of phase transition temperature and melting enthalpy (latent heat of melting) due to the surface tension effects. To a first approximation, both parameters must linearly depend on the specific ratio of the total surface of pores to their total volume, and experimental studies have mostly confirmed this result for the melting of 1-octadecene confined inside the pores of a wide range of various silicas (with the pores of different sizes and geometry).

     

Evaluation of blood plasma changes by differential scanning calorimetry in psoriatic patients treated with drugs

Psoriasis is a chronic inflammatory skin disease, most commonly resulting in the occurrence of red and silver scaly plaques. Application of differential scanning calorimetry (DSC) should be used as a new method to detect the different stages of the disease and to monitor medications with different anti-psoriatic drugs using patient’s blood plasma. The study included 72 white adults (35 men and 37 women; median age 56 years) with diagnosed psoriasis. According to the psoriasis area severity index (PASI) patients were selected into three groups: symptomless (PASI: 0), mild (PASI: 1–15), and serious symptoms (PASI: >15). According to medication patients were divided into untreated (n = 39) and treated (n = 33) groups. For systemic drug treatment cytostatic therapy (methotrexate, n = 12), retinoid treatment (acitretin, n = 10), and biologic response modifiers (adalimumab, n = 5; infliximab, n = 5; ustekinumab, n = 1) were applied. Denaturation of human plasma components were detected in Setaram Micro DSC II calorimeter. The patients had no third denaturation peak in the untreated mild and serious symptoms groups. In mild symptoms all the thermal parameters altered significantly, while in serious symptoms only the first melting and the calorimetric enthalpy altered significantly compared with symptoms-free states. In case of systematic cytostatic and retinoid drug treatment (methotrexate, n = 12; acitretin, n = 10) cases the DSC scans of patients with symptoms exhibited significant differences (p < 0.05) in melting temperatures and in calorimetric enthalpy compared with the untreated symptoms-free patients. Using biologic response modifier agents (adalimumab, infliximab, and ustekinumab) we had no enough samples for a statistical evaluation for each one, but after the intervention a stronger effect can be seen as in case of systematic drug treatment. In this study blood plasma measurement in psoriatic patients by DSC showed differences between untreated, conventional systemic drug treatment, and application of biologic response modifier agents, but further studies are needed to elucidate these relationships (supported by grant OTKA CO-272).     

On the anisotropy of the intermolecucular potential of the CO2-Ne system in the repulsive short-range region

Ab-initio computations at the STO-3G level have been performed on CO₂-Ne. The short-range interactions are roughly proportional to Σ_ir_i^?12, where the r_i are the distances from neon to the atoms in CO₂. In this empirical approximation, the anisotropy effects are conveniently revealed by the proportionality coefficient whose value depends on the angle between the OCO and C-Ne axes.