Control of arms of au stars size and its dependent cytotoxicity and photosensitizer effects in photothermal anticancer therapy

Gold nanostars (AuS NPs) are a very attractive nanomaterial, which is characterized by high effective transduction of the electromagnetic radiation into heat energy. Therefore, AuS NPs can be used as photosensitizers in photothermal therapy (PTT). However, understanding the photothermal conversion efficiency in nanostars is very important to select the most appropriate shape and size of AuS NPs. Therefore, in this article, the synthesis of AuS NPs with different lengths of star arms for potential application in PTT was investigated. Moreover, the formation mechanism of these AuS NPs depending on the reducer concentration is proposed. Transmission electron microscopy (TEM) with selected area diffraction (SEAD) and X-ray diffraction (X-Ray) showed that all the obtained AuS NPs are crystalline and have cores with similar values of the diagonal (parameter d), from 140 nm to 146 nm. However, the widths of the star arm edges (parameter c) and the lengths of the arms (parameter a) vary between 3.75 nm and 193 nm for AuS1 NPs to 6.25 nm and 356 nm for AuS4 NPs. Ultraviolet-visible (UV-Vis) spectra revealed that, with increasing edge widths and lengths of the star arms, the surface plasmon resonance (SPR) peak is shifted to the higher wavelengths, from 640 nm for AuS1 NPs to 770 nm for AuS4 NPs. Moreover, the increase of temperature in the AuS NPs solutions as well as the values of calculated photothermal efficiency grew with the elongation of the star arms. The potential application of AuS NPs in the PTT showed that the highest decrease of viability, around 75%, of cells cultured with AuS NPs and irradiated by lasers was noticed for AuS4 NPs with the longest arms, while the smallest changes were visible for gold nanostars with the shortest arms. The present study shows that photothermal properties of AuS NPs depend on edge widths and lengths of the star arms and the values of photothermal efficiency are higher with the increase of the arm lengths, which is correlated with the reducer concentration

Intermittency route to chaos and broadband high-frequency generation in semiconductor superlattice coupled to external resonator

We investigate the onset of broadband microwave chaos in the miniband semiconductor superlattice coupled to an external resonator. Our analysis shows that the transition to chaos, which is confirmed by calculation of Lyapunov exponents, is associated with the intermittency scenario. The evolution of the laminar phases and the corresponding Poincare maps with variation of a supercriticality parameter suggest that the observed dynamics can be classified as type I intermittency. We study the spatiotemporal patterns of the charge concentration and discuss how the frequency band of the chaotic current oscillations in semiconductor superlattice depends on the voltage applied

Lyapunov analysis of the spatially discrete-continuous system dynamics

The spatially discrete-continuous dynamical systems, that are composed of a spatially extended medium coupled with a set of lumped elements, are frequently met in different fields, ranging from electronics to multicellular structures in living systems. Due to the natural heterogeneity of such systems, the calculation of Lyapunov exponents for them appears to be a challenging task, since the conventional techniques in this case often become unreliable and inaccurate. The paper suggests an effective approach to calculate Lyapunov exponents for discrete-continuous dynamical systems, which we test in stability analysis of two representative models from different fields. Namely, we consider a mathematical model of a 1D transferred electron device coupled with a lumped resonant circuit, and a phenomenological neuronal model of spreading depolarization, which involves 2D diffusive medium. We demonstrate that the method proposed is able reliably recognize regular, chaotic and hyperchaotic dynamics in the systems under study

Fe3O4@SiO2@Au nanoparticles for MRI-guidedchemo/NIR photothermal therapy of cancer cells

Novel functionalized (biofunctionalization followed by cisplatin immobilization) Fe3O4@SiO2@Au nanoparticles (NPs) were designed. The encapsulation of Fe3O4 cores inside continuous SiO2 shells preserves their initial structure and strong magnetic properties, while the shell surface can be decorated by small Au NPs, and then cisplatin (cPt) can be successfully immobilized on their surface. The fabricated NPs exhibit very strong T2 contrasting properties for magnetic resonance imaging (MRI). The functionalized Fe3O4@SiO2@Au NPs are tested for a potential application in photothermal cancer therapy, which is simulated by irradiation of two colon cancer cell lines (SW480 and SW620) with a laser (λ = 808 nm, W = 100 mW cm−2). It is found that the functionalized NPs possess low toxicity towards cancer cells (∼10–15%), which however could be drastically increased by laser irradiation, leading to a mortality of the cells of ∼43–50%. This increase of the cytotoxic properties of the Fe3O4@SiO2@Au NPs, due to the synergic effect between the presence of cPt plus Au NPs and laser irradiation, makes these NPs perspective agents for potential (MRI)-guided stimulated chemo-photothermal treatment of cancer

Lyapunov stability of charge transport in miniband semiconductor superlattices

We discuss a numerical method for the calculation of the spectrum of Lyapunov exponents for spatially extended systems described by coupled Poisson and continuity equations. This approach was applied to the model of collective charge transport in semiconductor superlattices operating in the miniband transport regime. The method is in very good agreement with analytical results obtained for the steady state. As an illustrative example, we consider the collective electron dynamics in the superlattice subjected to an ac voltage and a tilted magnetic field, and conclusively show that, depending on the field parameters, the dynamics can exhibit periodic, quasiperiodic, or chaotic behavior

SOLARIS National Synchrotron Radiation Centre in Krakow, Poland

The SOLARIS synchrotron located in Krakow, Poland, is a third-generation light source operating at medium electron energy. The first synchrotron light was observed in 2015, and the consequent development of infrastructure lead to the first users’ experiments at soft X-ray energies in 2018. Presently, SOLARIS expands its operation towards hard X-rays with continuous developments of the beamlines and concurrent infrastructure. In the following, we will summarize the SOLARIS synchrotron design, and describe the beamlines and research infrastructure together with the main performance parameters, upgrade, and development plans

Working group on cephalopod fisheries and life history (Wgceph; outputs from 2022 meeting)

Rapports Scientifiques du CIEM. Volume 5, nº 1WGCEPH worked on six Terms of Reference. These involved reporting on the status of stocks; reviewing advances in stock identification, assessment for fisheries management and for the Ma- rine Strategy Framework Directive (MSFD), including some exploratory stock assessments; re- viewing impacts of human activities on cephalopods; developing identification guides and rec- ommendations for fishery data collection; describing the value chain and evaluating market driv- ers; and reviewing advances in research on environmental tolerance of cephalopods. ToR A is supported by an annual data call for fishery and survey data. During 2019–2021, com- pared to 1990–2020, cuttlefish remained the most important cephalopod group in terms of weight landed along the European North Atlantic coast, while loliginid squid overtook octopus as the second most important group. Short-finned squid remained the least important group in land- ings although their relative importance was almost double in 2019–2022 compared to 1992–2020. Total cephalopod landings have been fairly stable since 1992. Cuttlefish landings are towards the low end of the recent range, part of a general downward trend since 2004. Loliginid squid landings in 2019 were close to the maximum seen during the last 20 years but totals for 2020 and 2021 were lower. Annual ommastrephid squid landings are more variable than those of the other two groups and close to the maximum seen during 1992– 2021. Octopod landings have generally declined since 2002 but the amount landed in 2021 was higher than in the previous four years. Under ToR B we illustrate that the combination of genetic analysis and statolith shape analysis is a promising method to provide some stock structure information for L. forbsii. With the sum- mary of cephalopod assessments, we could illustrate that many cephalopod species could al- ready be included into the MSFD. We further provide material from two reviews in preparation, covering stock assessment methods and challenges faced for cephalopod fisheries management. Finally, we summarise trends in abundance indices, noting evidence of recent declines in cuttle- fish and some octopuses of the genus Eledone. Under ToR C, we describe progress on the reviews of (i) anthropogenic impacts on cephalopods and (ii) life history and ecology. In relation to life history, new information on Eledone cirrhosa from Portugal is included. Under ToR D we provide an update on identification guides, discuss best practice in fishery data collection in relation to maturity determination and sampling intensity for fishery monitoring. Among others, we recommend i) to include the sampling of cephalopods in any fishery that (a) targets cephalopods, (b) targets both cephalopods and demersal fishes or (c) takes cephalopods as an important bycatch, ii) Size-distribution sampling, iii) the use of standardized sampling pro- tocols, iv) an increased sampling effort in cephalopod. Work under ToR E on value chains and market drivers, in conjunction with the Cephs & Chefs INTERREG project, has resulted in two papers being submitted. Abstracts of these are in the report. Finally, progress under ToR F on environmental tolerance limits of cephalopods and climate en- velope models is discussed, noting the need to continue this work during the next cycle.info:eu-repo/semantics/publishedVersio