Synthesis of poly(sebacic anhydride): effect of various catalysts on structure and thermal properties

Combining different polymeric systems can be a useful tool to create new networks with different characteristics with respect to the starting materials. In this work, hydrogels composed of gellan gum (GG) and polyethylene glycol dimethacrylate (PEG-DMA) were realized to overcome the fragility problems of physical gels of GG, which limit their biological application as scaffold for tissue engineering. The two polymeric systems were combined using different synthetic approaches, with particular attention to the double network strategy (DN). The influence of several parameters on the mechanical properties, such as the time of diffusion and the molecular weight of PEG-DMA, were evaluated by rheological studies and compressive texture analyses. The hydrogels were also investigated for their ability to swell and release model molecules with different sterical hindrances, such as vitamin B12 and myoglobin. Finally, to estimate the biological safety of the hydrogels, their effect on mitochondrial function of human fibroblasts was investigated.     

Basic study of ceramic lithium strontium borates as thermal neutron scintillators

A special group of luminescence materials are scintillators for thermal neutron detection. Due to the properties of neutrons (contrary to e.g. electrons or gamma photons), a different approach has to be utilized—the high content of atoms with the sufficient absorption cross-section toward neutrons and lower material density are needed. This work pursues a basic study of LiSrBO₃ and LiSr₄(BO₃)₃ doped with cerium or europium—materials promising as thermal neutron scintillators. These borates exhibit promising properties such as the high content of lithium and boron, suitable density, and proper environment for luminescent ions. Radioluminescence of these ceramic borates doped with cerium and europium was examined and promising samples were further characterized by photoluminescence spectroscopy and radioluminescence and photoluminescence kinetics measurement. The radioluminescence study of these borates is published for the first time. Cerium-doped borates, in particular, exhibit a very promising response to an X-ray excitation.     

New path in the thermal cracking of triacylglycerols (canola and soybean oil)

Triacylglycerols (TGs) are naturally occurring oils abundant in many crops. A series of batch uncatalyzed thermal decomposition experiments were performed using canola and soybean oils to explore pathways of TG cracking. A detailed gas chromatographic protocol based on mass spectrometric identification and flame ionization quantification was applied to the organic liquid product generated upon cracking. Reaction conditions were identified that resulted in a novel organic liquid product (OLP) composition compared to previously reported work. Under these conditions (temperatures within a 420-440 °C range) a new route for TG thermolysis was discovered in which cracking reactions of original TG-bound fatty acids were nearly complete and led to the formation of 15-25 wt.% C₂-C₁₀ linear saturated monocarboxylic acids and ca. 30% linear alkanes. Less than 2 wt.% C₁₆-C₁₈ fatty acids which were originally present in the feedstocks as glycerol triesters were found in the OLP. These reactions appear to be kinetically controlled due to abundant hydrogen formation. This route provides a significant enrichment of low-MW compounds in the OLP (65-70 wt.% being <C₁₁) and thus may be considered as a new option for the production of replacement products for petroleum-based fuels and chemicals.     

Subcritical (hot/liquid) water dechlorination of PCBs (Aroclor 1254) with metal additives and in waste paint

No disposal option exists for "mixed wastes" such as paint scrapings that are co-contaminated with polychlorinated biphenyls (PCBs) and radioactive metals. Either removal or destruction of the PCBs is required prior to disposal. Comparison of subcritical water dechlorination (350 degrees C, 1 h) of Aroclor 1254 in paint scrapings (180 ppm) and of standard Aroclor 1254 showed significantly enhanced dechlorination in the presence of paint. While no significant degradation was observed for standard Aroclor (no paint), the dechlorination of PCBs in paint was 99, 99, and 80% for the hepta-, hexa-, and pentachlorinated congeners, respectively, indicating that metals in the paint enhanced the dechlorination reactions. Adding metals to the standard Aroclor (no paint) reactions enhanced PCB dechlorination in subcritical water in descending order of activity: Pb approximately = Cu > Al > Zn > Fe. In the presence of both zerovalent and divalent lead and zerovalent copper in subcritical water (350 degrees C, 1 h), 99% of the Aroclor 1254 mixture (tetra- to heptachlorinated biphenyls) was dechlorinated. High dechlorination (ca. 95%) was also achieved with zerovalent aluminum. In contrast to other metals, lead retained its degradation ability at a lower temperature of 250 degrees C after 18 h. The high degradation efficiency achieved using metal additives in water at reasonable temperatures and pressures demonstrates the potential for subcritical water dechlorination of PCBs in paint scrapings and, potentially, in other solid and liquid wastes.     

Adaptive Synthesis of Functional Amphiphilic Dendrons as a Novel Approach to Artificial Supramolecular Objects

Supramolecular structures, such as micelles, liposomes, polymerosomes or dendrimerosomes, are widely studied and used as drug delivery systems. The behavior of amphiphilic building blocks strongly depends on their spatial distribution and shape of polar and nonpolar component. This report is focused on the development of new versatile synthetic protocols for amphiphilic carbosilane dendrons (amp-CS-DDNs) capable of self-assembly to regular micelles and other supramolecular objects. The presented strategy enables the fine modification of amphiphilic structure in several ways and also enables the facile connection of a desired functionality. DLS experiments demonstrated correlations between structural parameters of amp-CS-DDNs and the size of formed nanoparticles. For detailed information about the organization and spatial distribution of amp-CS-DDNs assemblies, computer simulation models were studied by using molecular dynamics in explicit water.     

Association between Insertion-Deletion Polymorphism of the Angiotensin-Converting Enzyme Gene and Treatment Response to Antipsychotic Medications: A Study of Antipsychotic-Naïve First-Episode Psychosis Patients and Nonadherent Chronic Psychosis Patients

We investigated whether a functional insertion/deletion (I/D) polymorphism of angiotensin-converting enzyme (ACE) influenced antipsychotic treatment. At baseline, and after 8 weeks of treatment with various antipsychotic medications, we assessed patients’ Positive and Negative Syndrome Scale (PANSS) scores, PANSS factors, and metabolic-syndrome-related parameters (fasting plasma lipid and glucose levels, and body mass index). A total of 186 antipsychotic-naïve first-episode psychosis patients or nonadherent chronic psychosis individuals (99 males and 87 females) were genotyped by polymerase chain reaction analysis. The ACE-I/D polymorphism was significantly associated with changes in PANSS psychopathology only (p < 0.05). Compared to ACE-II homozygous males, ACE-DD homozygous and ACE-ID heterozygous males manifested significantly greater decreases in PANSS positive score, PANSS excitement factor, and PANSS cognitive factor. ACE-DD homozygous females manifested higher decreases in PANSS depression factor compared to ACE-II homozygous and ACE-ID heterozygous females. The polymorphism’s effect size was estimated as moderate to strong, while its contribution to the PANSS psychopathology ranged from ~5.4 to 8.7%, with the lowest contribution observed for PANSS positive score changes and the highest for PANSS depressive factor changes. Our results indicate that ACE-I/D polymorphism had a statistically significant but weak gender-specific impact on psychopathology data, and showed no association between ACE-I/D polymorphism and metabolic-syndrome-related parameters.     

Allosteric Modulation of Muscarinic Receptors by Cholesterol,Neurosteroids and Neuroactive Steroids

Muscarinic acetylcholine receptors are membrane receptors involved in many physiological processes. Malfunction of muscarinic signaling is a cause of various internal diseases, as well as psychiatric and neurologic conditions. Cholesterol, neurosteroids, neuroactive steroids, and steroid hormones are molecules of steroid origin that, besides having well-known genomic effects, also modulate membrane proteins including muscarinic acetylcholine receptors. Here, we review current knowledge on the allosteric modulation of muscarinic receptors by these steroids. We give a perspective on the research on the non-genomic effects of steroidal compounds on muscarinic receptors and drug development, with an aim to ultimately exploit such knowledge.     

Compositional and Structural Modifications by Ion Beam in Graphene Oxide for Radiation Detection Studies

In the present study, graphene oxide foils 10 μm thick have been irradiated in vacuum using same charge state (one charge state) ions, such as protons, helium and oxygen ions, at the same energies (3 MeV) and fluences (from 5 × 10¹¹ ion/cm² to 5 × 10¹⁴ ion/cm²). The structural changes generated by the ion energy deposition and investigated by X-ray diffraction have suggested the generation of new phases, as reduced GO, GO quantum dots and graphitic nanofibers, carbon nanotubes, amorphous carbon and stacked-cup carbon nanofibers. Further analyses, based on Rutherford Backscattering Spectrometry and Elastic Recoil Detection Analysis, have indicated a reduction of GO connected to the atomic number of implanted ions. The morphological changes in the ion irradiated GO foils have been monitored by Transmission Electron, Atomic Force and Scanning Electron microscopies. The present study aims to better structurally, compositionally and morphologically characterize the GO foils irradiated by different ions at the same conditions and at very low ion fluencies to validate the use of GO for radiation detection and propose it as a promising dosimeter. It has been observed that GO quantum dots are produced on the GO foil when it is irradiated by proton, helium and oxygen ions and their number increases with the atomic number of beam gaseous ion.     

Diastereoselective Synthesis of Novel Spiro-Phosphacoumarins and Evaluation of Their Anti-Cancer Activity

Herein we present the regio- and diastereoselective synthesis of novel pyrrolidine-fused spiro-dihydrophosphacoumarins via intermolecular [3 + 2] cycloaddition reaction. The presented approach is complementary to existing ones and provides an easy entry to the otherwise inaccessible derivatives. Additionally, the unprecedented pathway of the reaction of 4-hydroxycoumarin with azomethine ylides is described. The anti-cancer activity of the obtained compounds was tested in vitro, the most potent compound being 2.6-fold more active against the HuTu 80 cell line than the reference 5-fluorouracil, with a selectivity index > 32.