Search Results (9)

This study investigates the significant impact of metal–support interactions on catalytic reaction mechanisms at the interface of oxide-supported metal nanoparticles. The distinct and contrasting effects of SiO₂ and TiO₂ supports on reaction dynamics using NaBD₄ were studied and focused on the relative yields of [HD]/[H₂] and [D₂]/[H₂]. The findings show a consistent increase in HD yields with rising [BD₄⁻] concentrations. Notably, the sequence of HD yield enhancement follows the order of TiO₂-Au⁰-NPs < Au⁰-NPs < SiO₂-Au⁰-NPs. Conversely, the rate of H₂ evolution during BH₄^- hydrolysis exhibits an inverse trend, with TiO₂-Au⁰-NPs outperforming the others, followed by Au⁰-NPs and SiO₂-Au⁰-NPs, demonstrating the opposing effects exerted by the TiO₂ and SiO₂ supports on the catalytic processes. Further, the catalytic reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) confirms the catalytic mechanism, with TiO₂-Au⁰-NPs demonstrating superior activity. The catalytic activity observed aligns with the order of TiO₂-Au⁰-NPs > Au⁰-NPs > SiO₂-Au⁰-NPs, suggesting that SiO₂ donates electrons to Au⁰-NPs, while TiO₂ withdraws them. It is of interest to note that two very different processes, that clearly proceed via different mechanisms, are affected similarly by the supports. This study reveals that the choice of support material influences catalytic activity, impacting overall yield and efficiency. These findings underscore the importance of selecting appropriate support materials for tailored catalytic outcomes. Full article

The current need to find new advanced approaches to carry biologically active substances (conventional organic drugs, peptides, proteins (such as antibodies), and nucleic acid-based drugs (NABDs such as siRNA and miRNA)) in the body fluids, to realize targeted therapies and even personalized ones, goes hand in hand with research on the performance of new materials to better realize appropriate drug vectors [...] Full article

Activated alkenes such as cinnamates and chalcones can easily be converted to 2,3-dideuterio-arylpropionates and dideuteriochalcones, respectively, by the action of NaBD₄, AcOD in the presence of Pd on carbon. Toluene or benzene was used as solvent. It was shown that Pd on carbon was necessary for the reaction to proceed. Deuterium addition experiments were also carried out with NaBD₄, AcOD, D₂O in the presence of Pd on carbon. Full article

The objective of this study was to investigate the roles and tribological mechanisms of onion-like carbon nanoparticles derived from biodiesel soot (BDS) when applied in water (H₂O) and liquid paraffin (LP). In this study, we prepared nitric acid-treated BDS (NA-BDS) as an additive to H₂O and NA-BDS modified with oleylamine (NA-BDS-OLA) as an additive to LP. Raman spectroscopy, field-emission transmission electron microscopy, Fourier transform infrared spectroscopy, and zeta potentiometry were used to characterize the results of the nitric acid treatment and oleylamine modification. The tribological behaviors and corresponding mechanisms of the new onion-like carbon nanoparticles were evaluated using a ball-on-disc reciprocating tribometer, as well as field-emission scanning electron microscopy, three-dimensional laser scanning microscopy, and Raman spectroscopy. The results indicated that the additives NA-BDS and NA-BDS-OLA, which were onion-like carbon nanoparticles with sizes ranging from 35 to 40 nm, enhanced the antiwear and friction reduction properties of H₂O and LP, respectively. Through tribo-mechanisms, these types of soot can serve as spacers and ball bearings between the rubbing surfaces. Moreover, exfoliation under a high load as a result of the formation of a graphitic layer facilitates easy shearing. Full article

In the last years the rapid development of Nucleic Acid Based Drugs (NABDs) to be used in gene therapy has had a great impact in the medical field, holding enormous promise, becoming “the latest generation medicine” with the first ever siRNA-lipid based formulation approved by the United States Food and Drug Administration (FDA) for human use, and currently on the market under the trade name Onpattro™. The growth of such powerful biologic therapeutics has gone hand in hand with the progress in delivery systems technology, which is absolutely required to improve their safety and effectiveness. Lipid carrier systems, particularly liposomes, have been proven to be the most suitable vehicles meeting NABDs requirements in the medical healthcare framework, limiting their toxicity, and ensuring their delivery and expression into the target tissues. In this review, after a description of the several kinds of liposomes structures and formulations used for in vitro or in vivo NABDs delivery, the broad range of siRNA-liposomes production techniques are discussed in the light of the latest technological progresses. Then, the current status of siRNA-lipid delivery systems in clinical trials is addressed, offering an updated overview on the clinical goals and the next challenges of this new class of therapeutics which will soon replace traditional drugs. Full article

6R/S-deutero-α-d-mannopyranoside 1-phosphate was synthesised from a C6 aldehydic mannose thioglycoside donor in four steps. Using NaBD₄ as the reductant, isotopic enrichment at C6 was achieved and the resultant C6-deuterated material was converted through to the glycosyl 1-phosphate using a protection/glycosylation/deprotection sequence. The product was fully characterised by ¹H, ¹³C, ³¹P and 2D NMR, alongside MS analysis. Full article

Despite the advances in anticancer therapies, their effectiveness for many human tumors is still far from being optimal. Significant improvements in treatment efficacy can come from the enhancement of drug specificity. This goal may be achieved by combining the use of therapeutic molecules with tumor specific effects and delivery carriers with tumor targeting ability. In this regard, nucleic acid-based drug (NABD) and particularly small interfering RNAs (siRNAs), are attractive molecules due to the possibility to be engineered to target specific tumor genes. On the other hand, polymeric-based delivery systems are emerging as versatile carriers to generate tumor-targeted delivery systems. Here we will focus on the most recent findings in the selection of siRNA/polymeric targeted delivery systems for hepatocellular carcinoma (HCC), a human tumor for which currently available therapeutic approaches are poorly effective. In addition, we will discuss the most attracting and, in our opinion, promising siRNA-polymer combinations for HCC in relation to the biological features of HCC tissue. Attention will be also put on the mathematical description of the mechanisms ruling siRNA-carrier delivery, this being an important aspect to improve effectiveness reducing the experimental work. Full article

Among the several delivery materials available so far, polysaccharides represent very attractive molecules as they can undergo a wide range of chemical modifications, are biocompatible, biodegradable, and have low immunogenic properties. Thus, polysaccharides can contribute to significantly overcome the limitation in the use of many types of drugs, including anti-cancer drugs. The use of conventional anti-cancer drugs is hampered by their high toxicity, mostly depending on the indiscriminate targeting of both cancer and normal cells. Additionally, for nucleic acid based drugs (NABDs), an emerging class of drugs with potential anti-cancer value, the practical use is problematic. This mostly depends on their fast degradation in biological fluids and the difficulties to cross cell membranes. Thus, for both classes of drugs, the development of optimal delivery materials is crucial. Here we discuss the possibility of using different kinds of polysaccharides, such as chitosan, hyaluronic acid, dextran, and pullulan, as smart drug delivery materials. We first describe the main features of polysaccharides, then a general overview about the aspects ruling drug release mechanisms and the pharmacokinetic are reported. Finally, notable examples of polysaccharide-based delivery of conventional anti-cancer drugs and NABDs are reported. Whereas additional research is required, the promising results obtained so far, fully justify further efforts, both in terms of economic support and investigations in the field of polysaccharides as drug delivery materials. Full article