Search Results (25)

Background/Objectives. This manuscript presents an overview of advances in oncological radiotherapy as an effective treatment method for cancerous tumors, focusing on mechanisms of action within metabolite–antimetabolite systems. The urgency of this topic is underscored by the fact that cancer remains one of the leading causes of death worldwide: as of 2022, approximately 20 million new cases were diagnosed globally, accounting for about 0.25% of the total population. Given prognostic models predicting a steady increase in cancer incidence to 35 million cases by 2050, there is an urgent need for the latest developments in physics, chemistry, molecular biology, pharmacy, and strict adherence to oncological vigilance. The purpose of this work is to demonstrate the relationship between the nature and mechanisms of past diagnostic and therapeutic oncology approaches, their current improvements, and future prospects. Particular emphasis is placed on isotope technologies in the production of therapeutic nuclides, focusing on the mechanisms of formation of simple and complex theranostic compounds and their classification according to target specificity. Methods. The methodology involved searching, selecting, and analyzing information from PubMed, Scopus, and Web of Science databases, as well as from available official online sources over the past 20 years. The search was structured around the structure–mechanism–effect relationship of active pharmaceutical ingredients (APIs). The manuscript, including graphic materials, was prepared using a narrative synthesis method. Results. The results present a sequential analysis of materials related to isotope technology, particularly nucleus stability and instability. An explanation of theranostic principles enabled a detailed description of the action mechanisms of radiopharmaceuticals on various receptors within the metabolite–antimetabolite system using specific drug models. Attention is also given to radioactive nanotheranostics, exemplified by the mechanisms of action of radioactive nanoparticles such as Tc-99m, AuNPs, wwAgNPs, FeNPs, and others. Conclusions. Radiotheranostics, which combines the diagnostic properties of unstable nuclei with therapeutic effects, serves as an effective adjunctive and/or independent method for treating cancer patients. Despite the emergence of resistance to both chemotherapy and radiotherapy, existing nuclide resources provide protection against subsequent tumor metastasis. However, given the unfavorable cancer incidence prognosis over the next 25 years, the development of “preventive” drugs is recommended. Progress in this area will be facilitated by modern medical knowledge and a deeper understanding of ligand–receptor interactions to trigger apoptosis in rapidly proliferating cells. Full article

A comprehensive theoretical investigation of shape coexistence and transition phenomena in the neutron-deficient nucleus ${}^{66}\mathrm{Se}$, using complementary microscopic and phenomenological approaches, is presented. The analysis employs the Covariant Density Functional Theory with the Density-Dependent Meson Exchange Model interaction to map the potential energy surface. This microscopic foundation is complemented by calculations using the Bohr–Mottelson Hamiltonian with a sextic oscillator potential, specifically adapted to explore shape coexistence between spherical and $\gamma$-unstable configurations. The latter model successfully reproduces the experimental energy spectrum, including the critical low-lying $0_2^{+}$ state at 1226 keV—a key signature of shape coexistence. An analysis of probability density distributions indicates a distinctive manifestation of shape coexistence wherein different shapes exist without significant mixing in the states. These findings provide crucial insights into the structural dynamics of ${}^{66}\mathrm{Se}$ and establish it as an important case study for understanding shape evolution in neutron-deficient nuclei beyond the $N=Z$ line. Full article

The pseudo-spin symmetry (PSS) provides an important angle to understand nuclear microscopic structure and the novel phenomena found in unstable nuclei. The relativistic Hartree–Fock (RHF) theory, that takes the important degrees of freedom associated with the $\pi$-meson and $\rho$-tensor ($\rho$-T) couplings into account, provides an appropriate description of the PSS restoration in realistic nuclei, particularly for the pseudo-spin (PS) doublets with high angular momenta ($\tilde{l}$). The investigations of the PSS within the RHF theory are recalled in this paper by focusing on the effects of the Fock terms. Aiming at common artificial shell closures appearing in previous relativistic mean-field calculations, the mechanism responsible for the PSS restoration of high-$\tilde{l}$ orbits is stressed, revealing the manifestation of nuclear in-medium effects on the PSS, and thus, providing qualitative guidance on modeling the in-medium balance between nuclear attractions and repulsions. Moreover, the essential role played by the $\rho$-T coupling, that contributes mainly via the Fock terms, is introduced as combined with the relations between the PSS and various nuclear phenomena, including the shell structure and the evolution, novel halo and bubble-like phenomena, and the superheavy magicity. As the consequences of the nuclear force in complicated nuclear many-body systems, the PSS itself and the mechanism therein can not only deepen our understanding of nuclear microscopic structure and relevant phenomena, but also provide special insight into the nature of the nuclear force, which can further enrich our knowledge of nuclear physics. Full article

Radioactivity is a process in which the nuclei of unstable atoms spontaneously decay, producing other nuclei and releasing energy in the form of ionizing radiation in the form of alpha (α) and beta (β) particles as well as the emission of gamma (γ) electromagnetic waves. People may be exposed to radiation in various forms, as casualties of nuclear accidents, workers in power plants, or while working and using different radiation sources in medicine and health care. Acute radiation syndrome (ARS) occurs in subjects exposed to a very high dose of radiation in a very short period of time. Each form of radiation has a unique pathophysiological effect. Unfortunately, higher organisms—human beings—in the course of evolution have not acquired receptors for the direct “capture” of radiation energy, which is transferred at the level of DNA, cells, tissues, and organs. Radiation in biological systems depends on the amount of absorbed energy and its spatial distribution, particularly depending on the linear energy transfer (LET). Photon radiation with low LET leads to homogeneous energy deposition in the entire tissue volume. On the other hand, radiation with a high LET produces a fast Bragg peak, which generates a low input dose, whereby the penetration depth into the tissue increases with the radiation energy. The consequences are mutations, apoptosis, the development of cancer, and cell death. The most sensitive cells are those that divide intensively—bone marrow cells, digestive tract cells, reproductive cells, and skin cells. The health care system and the public should raise awareness of the consequences of ionizing radiation. Therefore, our aim is to identify the consequences of ARS taking into account radiation damage to the respiratory system, nervous system, hematopoietic system, gastrointestinal tract, and skin. Full article

Recent advancements in studying long chains of unstable nuclei have revitalised interest in investigating the hyperfine anomaly. Hyperfine anomaly is particularly relevant for determining nuclear magnetic dipole moments using hyperfine structures where it limits the accuracy. This research paper focuses on the calculation of the differential Breit-Rosenthal effect for the $6p^2{}^3{P}_{1,2}$, ${}^1{D}_2$ and $6p7s{}^3{P}_1$ states in Pb, utilising the multi-configurational Dirac-Hartree-Fock code, GRASP2018. The findings show that the differential Breit-Rosenthal effect is typically less than $0.1/\mathrm{f}{\mathrm{m}}^2$, which is often much smaller than the Bohr-Weisskopf effect. The differential Breit-Rosenthal effect for the $6p^2{}^3{P}_2$ state is one order of magnitude smaller than the rest, which is why this state seems to be insensible to the hyperfine anomaly. Full article

BL Lac objects are active galactic nuclei notable for a beamed nonthermal radiation, which is generated in one of the relativistic jets forming a small angle to the observer’s line-of-sight. The broadband spectra of BL Lacs show a two-component spectral energy distribution (SED). High-energy-peaked BL Lacs (HBLs) exhibit their lower-energy (synchrotron) peaks at UV to X-ray frequencies. The origin of the higher-energy SED component, representing the $\gamma$-ray range in HBLs, is still controversial and different emission scenarios (one- and multi-zone synchrotron self-Compton, hadronic etc.) are proposed. In $\gamma$-rays, HBLs show a complex flaring behavior with rapid and large-amplitude TeV-band variations on timescales down to a few minutes. This review presents a detailed characterization of the hypothetical emission mechanisms which could contribute to the $\gamma$-ray emission, their application to the nearby TeV-detected HBLs, successes in the broadband SED modeling and difficulties in the interpretation of the observational data. I also overview the unstable processes to be responsible for the observed $\gamma$-ray variability and particle energization up to millions of Lorentz factors (relativistic shocks, magnetic reconnection, turbulence and jet-star interaction). Finally, the future prospects for solving the persisting problems by means of the dedicated gamma-ray observations and sophisticated simulations are also addressed. Full article

To improve the constraints of symmetry energy at subsaturation density, measuring and accumulating more neutron skin data for neutron-rich unstable nuclei is naturally required. Aiming to probe the neutron skin of unstable nuclei by using low-intermediate-energy heavy-ion collisions, we develop a new version of an improved quantum molecular dynamics model, in which the neutron skin of the initial nucleus and the mean-field potential in nucleon propagation are consistently treated. Our calculations show that the three observables, such as the cross-sections of the primary projectile-like residues with $A>100$ (${\sigma }_{A>100}$), the difference of ${\sigma }_{A>100}$ between ${}^{132}$Sn + ${}^{124}$Sn and ${}^{124}$Sn + ${}^{124}$Sn systems ($\delta {\sigma }_{A>100}$), and the neutron-to-proton yield ratio ($R(n/p)$) in the transverse direction, could be used to measure the neutron skin of the unstable nuclei and to constrain the slope of the symmetry energy in the future. Full article

With advanced integrated circuit semiconductor chips, the uniformity of microstructure and texture is increasingly required for tantalum (Ta) targets. A combination of warm rolling and 135° cross rolling (CR) at the temperature of 500 °C and 800 °C, i.e., warm cross rolling (WCR), was carried out in tantalum (Ta) plates to investigate the evolution of deformed microstructure and texture. Subsequently, these rolled samples were annealed to analyze the recrystallized microstructure. Results exhibited that WCR samples formed a relatively uniform and weak texture distribution along the thickness direction. The reduction in the proportion of low-angle grain boundaries (LAGBs) was associated with the lower Peierls stresses to be overcome for dislocation motion due to thermal activation in the WCR sample. High grain boundary energy was observed in WCR samples, and WCR can promote dynamic recovery of samples to produce sub-crystals (thermodynamically unstable and serving as nuclei for subsequent recrystallization). Fine average grain size and high content of recrystallized grains with random orientation were obtained after annealing in the WCR sample. This study will provide a theoretical reference for the precise optimization of tantalum process parameters and the improvement in the target material’s performance. Full article

Nuclei that are unstable with respect to double beta decay are potentially interesting for a novel Dark Matter (DM) direct detection approach. In particular, a Majorana DM fermion inelastically scattering on a double beta unstable nucleus could stimulate its decay. Thanks to the exothermic nature of the stimulated double beta decay, this detection approach would allow for also investigating light DM fermions, a class of DM candidates that evade the detection capability of the traditional elastic scattering experiments. The upper limits on the nucleus scattering cross sections and the expected signal distribution for different DM masses are shown and compared with the existing data for the case of the ⁷⁶Ge nucleus. Full article

The high salinity of soil salts limits plant growth. Wheat is sensitive to toxic levels of mineral salts. Salinity leads to the accumulation of toxic ions in all organs of wheat. Depending on the level of ion accumulation, wheat is defined as salt stress-tolerant or -sensitive. The wheat variety Zolotaya accumulated Cl⁻ and Na⁺ ions to a greater extent than the Orenburgskaya 22 variety. The accumulation of toxic ions was accompanied by an increase in ROS and an increase in damage to root tissues up to 80% in the Zolotaya variety. The formation of autophagosomes is considered a defense mechanism against abiotic stresses in plants. At a concentration of 150 mM NaCl, an increase in the expression level of TOR, which is a negative regulator of the formation of autophagosomes, occurred. The level of TOR expression in the Zolotaya variety was 2.8 times higher in the roots and 3.8 times higher in the leaves than in the Orenburgskaya 22 variety. Under the action of salinity, homeostasis was disturbed in the root cells and ROS production accumulated. In the unstable variety Zolotaya, ROS was found in the cap zone and the root meristem in contrast to the resistant variety Orenburgskaya 22 in which ROS production was found only in the cap zone. Accumulation of ROS production triggered autophagy and PCD. PCD markers revealed DNA breaks in the nuclei and metaphase chromosomes, cells with a surface location of phosphatidylserine, and the release of cytochrome c into the cytoplasm, which indicates a mitochondrial pathway for the death of part of the root cells during salinity. Based on electron microscopy data, mitophagy induction was revealed in wheat root and leaf cells under saline conditions. Full article

Remarkable chiral activity is donated to a copper deposit surface by magneto-electrodeposition, whose exact mechanism has been clarified by the three-generation model. In copper deposition under a vertical magnetic field, a macroscopic tornado-like rotation called the vertical magnetohydrodynamic (MHD) flow (VMHDF) emerges on a disk electrode, inducing the precessional motions of various chiral microscopic MHD vortices: First, chiral two-dimensional (2D) nuclei develop on an electrode by micro-MHD vortices. Then, chiral three-dimensional (3D) nuclei grow on a chiral 2D nucleus by chiral nano-MHD vortices. Finally, chiral screw dislocations are created on a chiral 3D nucleus by chiral ultra-micro MHD vortices. These three processes constitute nesting boxes, leading to a limiting enantiomeric excess (ee) ratio of 0.125. This means that almost all chiral activity of copper electrodes made by this method cannot exceed 0.125. It also became obvious that chirality inversion by chloride additive arises from the change from unstable to stable nucleation by the specific adsorption of it. Full article

Neutron stars are the densest objects in the Universe. In this paper, we consider the so-called inner crust—the layer where neutron-excess nuclei are immersed in the degenerate gas of electrons and a sea of quasi-free neutrons. It was generally believed that spherical nuclei become unstable with respect to quadrupole deformations at high densities, and here, we consider this instability. Within the perturbative approach, we show that spherical nuclei with equilibrium number density are, in fact, stable with respect to infinitesimal quadrupole deformation. This is due to the background of degenerate electrons and associated electrostatic potential, which maintain stability of spherical nuclei. However, if the number of atomic nuclei per unit volume is much less than the equilibrium value, instability can arise. To avoid confusion, we stress that our results are limited to infinitesimal deformations and do not guarantee strict thermodynamic stability of spherical nuclei. In particular, they do not exclude that substantially non-spherical nuclei (so-called pasta phase) represent a thermodynamic equilibrium state of the densest layers of the neutron star crust. Rather, our results point out that spherical nuclei can be metastable even if they are not energetically favourable, and the timescale of transformation of spherical nuclei to the pasta phases should be estimated subsequently. Full article

Two novel phosphine ligands, Ph₂PCH₂N(CH₂CH₃)₃ (1) and Ph₂PCH₂N(CH₂CH₂CH₂CH₃)₂ (2), and six new metal (Cu(I), Ir(III) and Ru(II)) complexes with those ligands: iridium(III) complexes: Ir(η5-Cp*)Cl₂(1) (1a), Ir(η5-Cp*)Cl₂(2) (2a) (Cp*: Pentamethylcyclopentadienyl); ruthenium(II) complexes: Ru(η6-p-cymene)Cl₂(1) (1b), Ru(η6-p-cymene)Cl₂(2) (2b) and copper(I) complexes: [Cu(CH₃CN)₂(1)BF₄] (1c), [Cu(CH₃CN)₂(2)BF₄] (2c) were synthesized and characterized using elemental analysis, NMR spectroscopy, and ESI-MS spectrometry. Copper(I) complexes turned out to be highly unstable in the presence of atmospheric oxygen in contrast to ruthenium(II) and iridium(III) complexes. The studied Ru(II) and Ir(III) complexes exhibited promising cytotoxicity towards cancer cells in vitro with IC₅₀ values significantly lower than that of the reference drug—cisplatin. Confocal microscopy analysis showed that Ru(II) and Ir(III) complexes effectively accumulate inside A549 cells with localization in cytoplasm and nuclei. A precise cytometric analysis provided clear evidence for the predominance of apoptosis in induced cell death. Furthermore, the complexes presumably induce the changes in the cell cycle leading to G2/M phase arrest in a dose-dependent manner. Gel electrophoresis experiments revealed that Ru(II) and Ir(III) inorganic compounds showed their unusual low genotoxicity towards plasmid DNA. Additionally, metal complexes were able to generate reactive oxygen species as a result of redox processes, proved by gel electrophoresis and cyclic voltamperometry. In vitro cytotoxicity assays were also carried out within multicellular tumor spheroids and efficient anticancer action on these 3D assemblies was demonstrated. It was proven that the hydrocarbon chain elongation of the phosphine ligand coordinated to the metal ions does not influence the cytotoxic effect of resulting complexes in contrast to metal ions type. Full article

Acetylsalicylic acid (ASA) is widely used in secondary prevention of cardiovascular (CV) disease, mainly because of its antithrombotic effects. Here, we investigated whether ASA can prevent the progression of vessel wall remodelling, atherosclerosis, and CV complications in apolipoprotein E deficient (ApoE^−/−) mice, a model of stable atherosclerosis, and in ApoE^−/− mice with a mutation in the fibrillin-1 gene (Fbn1^C1039G+/−), which is a model of elastic fibre fragmentation, accompanied by exacerbated unstable atherosclerosis. Female ApoE^−/− and ApoE^−/−Fbn1^C1039G+/− mice were fed a Western diet (WD). At 10 weeks of WD, the mice were randomly divided into four groups, receiving either ASA 5 mg/kg/day in the drinking water (ApoE^−/− (n = 14), ApoE^−/−Fbn1^C1039G+/− (n = 19)) or plain drinking water (ApoE^−/− (n = 15), ApoE^−/−Fbn1^C1039G+/− (n = 21)) for 15 weeks. ApoE^−/−Fbn1^C1039G+/− mice showed an increased neutrophil–lymphocyte ratio (NLR) compared to ApoE^−/− mice, and this effect was normalised by ASA. In the proximal ascending aorta wall, ASA-treated ApoE^−/−Fbn1^C1039G+/− mice showed less p-SMAD2/3 positive nuclei, a lower collagen percentage and an increased elastin/collagen ratio, consistent with the values measured in ApoE^−/− mice. ASA did not affect plaque progression, incidence of myocardial infarction and survival of ApoE^−/−Fbn1^C1039G+/− mice, but systolic blood pressure, cardiac fibrosis and hypertrophy were reduced. In conclusion, ASA normalises the NLR, passive wall stiffness and cardiac remodelling in ApoE^−/−Fbn1^C1039G+/− mice to levels observed in ApoE^−/− mice, indicating additional therapeutic benefits of ASA beyond its classical use. Full article