Drug-Loaded Polymeric Particulated Systems for Ophthalmic Drugs Release

Drug delivery to the anterior or posterior segments of the eye is a major challenge due to the protection barriers and removal mechanisms associated with the unique anatomical and physiological nature of the ocular system. The paper presents the preparation and characterization of drug-loaded polymeric particulated systems based on pre-emulsion coated with biodegradable polymers. Low molecular weight biopolymers (chitosan, sodium hyaluronate and heparin sodium) were selected due to their ability to attach polymer chains to the surface of the growing system. The particulated systems with dimensions of 190–270 nm and a zeta potential varying from −37 mV to +24 mV depending on the biopolymer charges have been obtained. Current studies show that particles release drugs (dexamethasone/pilocarpine/bevacizumab) in a safe and effective manner, maintaining therapeutic concentration for a longer period of time. An extensive modeling study was performed in order to evaluate the drug release profile from the prepared systems. In a multifractal paradigm of motion, nonlinear behaviors of a drug delivery system are analyzed in the fractal theory of motion, in order to correlate the drug structure with polymer. Then, the functionality of a SL(2R) type “hidden symmetry” implies, through a Riccati type gauge, different “synchronization modes” (period doubling, damped oscillations, quasi-periodicity and intermittency) during the drug release process. Among these, a special mode of Kink type, better reflects the empirical data. The fractal study indicated more complex interactions between the angiogenesis inhibitor Bevacizumab and polymeric structure.     

The C30-Modulation of Betulinic Acid Using 1,2,4-Triazole: A Promising Strategy for Increasing Its Antimelanoma Cytotoxic Potential

Cancer, in all its types and manifestations, remains one of the most frequent causes of death worldwide; an important number of anticancer drugs have been developed from plants, fungi and animals, starting with natural compounds that were later derivatized in order to achieve an optimized pharmacokinetic/pharmacological profile. Betulinic acid is a pentacyclic triterpenic compound that was identified as an anticancer agent whose main advantage consists in its selective activity, which ensures the almost total lack of cytotoxic side effects. Conjugates of betulinic acid with substituted triazoles, scaffolds with significant pharmacological properties, were synthesized and tested as anticancer agents in order to achieve new therapeutic alternatives. The current paper aims to obtain a C30-1,2,4-triazole derivative of betulinic acid simultaneously acetylated at C3 whose biological activity was tested against RPMI melanoma cells. The compound revealed significant cytotoxic effects at the tested concentrations (2, 10 and 50 μΜ) by significantly decreasing the cell viability to 88.3%, 54.7% and 24.5%, respectively, as compared to the control. The compound’s testing in normal HaCaT cells showed a lack of toxicity, which indicates its selective dose-dependent anticancer activity. The investigation of its underlying molecular mechanism revealed an apoptotic effect induced at the mitochondrial level, which was validated through high-resolution respirometry studies.     

Analysis of VOCs in Urine Samples Directed towards of Bladder Cancer Detection

Bladder cancer is one of most common types of cancer diagnosed in the genitourinary tract. Typical tests are costly and characterized by low sensitivity, which contributes to a growing interest in volatile biomarkers. Head space solid phase microextraction (SPME) was applied for the extraction of volatile organic compounds from urine samples, and gas chromatography time of flight mass spectrometry (GC×GC TOF MS) was used for the separation and detection of urinary volatiles. A cohort of 40 adult patients with bladder cancer and 57 healthy persons was recruited. Different VOC profiles were obtained for urine samples taken from each group. Twelvecompounds were found only in the samples from theBC group.The proposed candidate biomarkers are butyrolactone; 2-methoxyphenol; 3-methoxy-5-methylphenol; 1-(2,6,6-trimethylcyclohexa-1,3-dien-1-yl)-2-buten-1-one; nootkatone and 1-(2,6,6-trimethyl-1-cyclohexenyl)-2-buten-1-one.Since most of the studies published in the field are proving the potential of VOCs detected in urine samples for the screening and discrimination of patients with bladder cancer from healthy, but rarely presenting the identity of proposed biomarkers, our study represents a novel approach.     

Preparation of photocrosslinked sol‐gel composites based on urethane‐acrylic matrix,silsesquioxane sequences,TiO2, and Ag/Au Nanoparticles for use in photocatalytic applications

An acid urethane oligodimethacrylate based on poly(ethylene glycol) was synthesized and used in the preparation of hybrid composites containing silsesquioxane sequences and titania domains formed through sol‐gel reactions along with silver/gold nanoparticles (Ag/Au NPs) in situ photogenerated during the UV‐curing process. The photopolymerization kinetics studied by Fourier transform infrared spectroscopy and photoDSC showed that the photoreactivity of the investigated formulations depends on the amount of titanium butoxide (5–20 wt %) added in the system subjected to UV irradiation. The introduction of 1 wt % AgNO₃/AuBr₃ in formulations slightly improved the degree of conversion but diminished the polymerization rates. The formation of hybrid materials comprising predominantly amorphous TiO₂/SiO₂ NPs, with or without Ag/Au NPs, was confirmed through specific analyses. The evaluation of photocatalytic activity demonstrated that the synthesized hybrid films are suitable for the complete removal of organic pollutants (phenolic compounds) from water under UV irradiation (200–350 min) at low intensity (found in the solar radiation). © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1189–1204     

Obtaining of hybrid nanocomposites by simultaneous photopolymerization of some urethane monomers and photoinduced formation of gold nanoparticles

Urethane–urea dimethacrylates were synthesized and used in the preparation of nanocomposites containing gold nanoparticles (Au NPs) in situ photogenerated during the UV‐curing process in the absence of reducing agent. A study of the photopolymerization kinetics showed that the photoreactivity of the monomers alone or in combination with a dual urethane benzophenone (BP) macromer is dependent on the nature of photoinitiator (Irgacure819, BP/amine) and the formulation composition. It was found that the addition of 1 wt % AuBr₃ in monomers slightly improved the polymerization rate and the degree of conversion. The formation of Au NPs into the network was confirmed through UV–vis, XRD, EDX, SAXS, and TEM analyses, the last indicating the existence of NPs with size around 8.5 nm and spherical/triangle shapes. On addition of 10 wt % 2[N‐methacryloyloxyethyl‐(N'‐2‐thioethyl)] (urea) in formulation, the Au NPs (200 nm) became predominantly cubic/hexagonal in shape. The composite films emit fluorescence at 575 nm, and this property could be exploited in the field of fluorescent bio/sensors. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 728–738     

Simple and Versatile Molecular Donors for Organic Photovoltaics Prepared by Metal‐Free Synthesis

Donor–acceptor molecules (D‐π‐A) built by connecting a diphenylhydrazone block to a dicyanovinyl acceptor group via various thiophene‐based π‐conjugating spacers ( 1 – 5 ) were synthesized from mono‐ or dialdehydes by a simple metal‐free procedure. Cyclic voltammetry and UV/Vis absorption spectroscopy show that the extension and/or increase of the donor strength of the spacer produces a decrease of the HOMO and LUMO energy level, a red shift of the absorption spectrum and an increase of the molecular absorption coefficient. Compared to solutions, the optical spectra of spin‐cast thin films of compounds 1–3 show a broadening and red shift of the absorption bands, consistent with the formation of J‐aggregates. In contrast the blue shift observed for the EDOT‐containing compounds 4 and 5 suggests the presence of H‐aggregates. Solution‐cast and vacuum‐deposited films of donors 1–5 were evaluated in solar cells with fullerene C₆₀ as acceptor. A power‐conversion efficiency among the highest reported for bilayer devices of basic configuration was obtained with compound 2 . On the other hand, the results obtained with 4 and 5 suggest that the presence of EDOT in the structure can have deleterious effects on the organization and performances of the donor material.     

Creation of twistless circles in a model of stellar pulsations

In the present paper, we study the Poincaré map associated to a periodic perturbation, both in space and time, of a linear Hamiltonian system. The dynamical system embodies the essential physics of stellar pulsations and provides a global and qualitative explanation of the chaotic oscillations observed in some stars. We show that this map is an area preserving one with an oscillating rotation number function. The nonmonotonic property of the rotation number function induced by the triplication of the elliptic fixed point is superposed on the nonmonotonic character due to the oscillating perturbation. This superposition leads to the co-manifestation of generic phenomena such as reconnection and meandering, with the nongeneric scenario of creation of vortices. The nonmonotonic property due to the triplication bifurcation is shown to be different from that exhibited by the cubic Hénon map, which can be considered as the prototype of area preserving maps which undergo a triplication followed by the twistless bifurcation. Our study exploits the reversibility property of the initial system, which induces the time-reversal symmetry of the Poincaré map.     

Ethanol adsorption, decomposition and oxidation on Ir(111): a high resolution XPS study.

Ethanol (C(2)H(5)OH) adsorption, decomposition and oxidation is studied on Ir(111) using high-energy resolution, fast XPS and temperature-programmed desorption. During heating of an adsorbed ethanol layer a part of the C(2)H(5)OH(ad) desorbs molecularly, and another part remains on the surface and decomposes around 200 K; these two decomposition pathways are identified, as via acetyl (H(3)C--C=O) and via CO(ad)+CH(3ad), respectively. Acetyl and CH(3ad) decompose around 300 K into CH(ad) (and CO(ad)). CH(ad) decomposes forming C(x) and H(2) around 520 K. In the presence of O(ad) an acetate intermediate is formed around 180 K, as well as a small amount of CH(3ad) and CO(ad). Acetate decomposes between 400-480 K into CO(2), H(2)(/H(2)O) and CH(ad).     

Evaluation of Detector Position and Light Fluence Distribution Using an Infrared Navigation System during Pleural Photodynamic Therapy†

Photodynamic therapy (PDT) has been used to treat malignant pleural mesothelioma. Current practice involves delivering light to a prescribed light fluence with a point source, monitored by eight isotropic detectors inside the pleural cavity. An infrared (IR) navigation system was used to track the location of the point source throughout the treatment. The recorded data were used to reconstruct the pleural cavity and calculate the light fluence to the whole cavity. An automatic algorithm was developed recently to calculate the detector positions based on recorded data within an hour. This algorithm was applied to patient case studies and the calculated results were compared to the measured positions, with an average difference of 2.5 cm. Calculated light fluence at calculated positions were compared to measured values. The differences between the calculated and measured light fluence were within 14% for all cases, with a fixed scattering constant and a dual correction method. Fluence-surface histogram (FSH) was calculated for photofrin-mediated PDT to be able to cover 80% of pleural surface area to 50 J cm⁻²(83.3% of 60 J cm⁻²). The study demonstrates that it will be possible to eliminate the manual measurement of the detector positions, reducing the patient's time under anesthesia.     

Simple and double pyridinium salts with cyanobiphenyl groups as ionic liquids and ionic liquid crystals: synthesis and investigation of thermal behavior

Research on Chemical Intermediates - A series of mono- and di-cationic pyridinium salts with one or two promesogenic cyanobiphenyl groups and different counterions, bromide, dodecylsulfate or...