Thermodynamics, formation dynamics, and structural correlations in the bulk amorphous phase of the phase-field crystal model.

We investigate bulk thermodynamic and microscopic structural properties of amorphous solids in the framework of the phase-field crystal (PFC) model. These are metastable states with a non-uniform density distribution, having no long-range order. From extensive numerical simulations, we determine the distribution of free energy density values in varying size amorphous systems and also the point-to-set correlation length, which is the radius of the largest volume of amorphous one can take while still having the particle arrangements within the volume determined by the particle ordering at the surface of the chosen volume. We find that in the thermodynamic limit, the free energy density of the amorphous tends toward a value that has a slight dependence on the initial state from which it was formed-i.e., it has a formation history dependence. The amorphous phase is observed to form on both sides of the liquid linear-stability limit, showing that the liquid to amorphous transition is first order, with an associated finite free energy barrier when the liquid is metastable. In our simulations, this is demonstrated when the noise in the initial density distribution is used to induce nucleation events from the metastable liquid. Depending on the strength of the initial noise, we observe a variety of nucleation pathways, in agreement with previous results for the PFC model, which show that amorphous precursor mediated multi-step crystal nucleation can occur in colloidal systems.

Dynamical Density Functional Theory for the Drying and Stratification of Binary Colloidal Dispersions.

We develop a dynamical density functional theory based model for the drying of colloidal films on planar surfaces. We consider mixtures of two different sizes of hard-sphere colloids. Depending on the solvent evaporation rate and the initial concentrations of the two species, we observe varying degrees of stratification in the final dried films. Our model predicts the various structures described in the literature previously from experiments and computer simulations, in particular the small-on-top stratified films. Our model also includes the influence of adsorption of particles to the interfaces.

Phase field modelling of spinodal decomposition in the oil/water/asphaltene system.

In this paper the quantitative applicability of van der Sman/van der Graaf type Ginzburg-Landau theories of surfactant assisted phase separation [van der Sman et al., Rheol. Acta, 2006, 46, 3] is studied for real systems displaying high surfactant concentrations at the liquid-liquid interface. The model is applied for the water/heptane/asphaltene system (a model of heavy crude oil), for which recent molecular dynamics (MD) simulations provide microscopic data needed to calibrate the theory. A list of general requirements is set up first, which is then followed by analytical calculations of the equilibrium properties of the system, such as the equilibrium liquid densities, the adsorption isotherm and the interfacial tension. Based on the results of these calculations, the model parameters are then determined numerically, yielding a reasonable reproduction of the MD density profiles. The results of time-dependent simulations addressing the dynamical behaviour of the system will also be presented. It will be shown that the competition between the diffusion and hydrodynamic time scales can lead to the formation of an emulsion. We also address the main difficulties and limitations of the theory regarding quantitative modelling of surfactant assisted liquid phase separation.

Heterogeneous nucleation of/on nanoparticles: a density functional study using the phase-field crystal model.

Crystallization of supersaturated liquids usually starts by heterogeneous nucleation. Mounting evidence shows that even homogeneous nucleation in simple liquids takes place in two steps; first a dense amorphous precursor forms, and the crystalline phase appears via heterogeneous nucleation in/on the precursor cluster. Herein, we review recent results by a simple dynamical density functional theory, the phase-field crystal model, for (precursor-mediated) homogeneous and heterogeneous nucleation of nanocrystals. It will be shown that the mismatch between the lattice constants of the nucleating crystal and the substrate plays a decisive role in determining the contact angle and nucleation barrier, which were found to be non-monotonic functions of the lattice mismatch. Time dependent studies are essential as investigations based on equilibrium properties often cannot identify the preferred nucleation pathways. Modeling of these phenomena is essential for designing materials on the basis of controlled nucleation and/or nano-patterning.

[Nutcracker syndrome - treated by surgery]. / Nutcracker-syndroma sikerrel operált esete.

The nutcracker syndrome is caused by tight compression of the left renal vein between the superior mesenteric artery and the abdominal aorta. The consequences may vary between symptomfree conditions through moderate proteinuria and hypertension to severe hematuria. All imaging modalities have been used during diagnostic workup. Wide varieties of surgical and endovascular solutions are reported aiming to achieve decompression of the renal vein like venous or arterial transposition, bypass, renal autotransplantation, stenting, nephrectomy, etc. In our case a 21-year-old man the nutcracker syndrome was successfully solved by transposition of the superior mesenteric artery into the infrarenal aorta.

[PET radiopharmaceuticals: novelties and new possibilities]. / PET-radiofarmakonok: újdonságok és új lehetoségek.

18F-fluoro-deoxyglucose (FDG) can be considered as the "work-horse" of PET/CT and PET/MR imaging modalities. FDG provides insight in the pathophysiology of tumors and metastases from the point of view of sugar consumption. On the other hand, amino acid metabolism, expression of various receptors in the cells or on the surface of the cells, angiogenesis, appearance of hypoxic cells/tissues and apoptosis also participate in the pathophysiological processes and may have importance in determining the treatment strategy for patients or in monitoring the chosen therapy. Many molecules involved can be labeled by (18)F radionuclide but certain metabolisms require (11)C-labelled agents. Molecular imaging is of key importance in cancer research and various metal complexes containing (44)Sc, (64)Cu, (68)Ga, (86)Y, (89)Zr positron emitters can be very useful in this activity.

[Effectiveness and safety of total thyroidectomy in the management of benign multinodular goiters]. / A total thyreoidectomia hatásossága és biztonságossága a jóindulatú multinodularis golyvák kezelésében.

BACKGROUND: The appropriate surgical procedure for benign multinodular goiters is debated. We report our clinical experience of performing total thyroidectomy for multinodular goiters, focusing on the outcome and complications to evaluate the efficacy and safety. MATERIAL AND METHODS: The medical records of 264 patients who underwent total thyroidectomy for multinodular goiter between 2000 and 2006 were reviewed retrospectively. We examined the indications for operation, average hospital stay, early and late postoperative complications, the results of the final pathology in particular the frequency of incidental thyroid cancers and the recurrence rates after an average 6.2 years follow-up. The results were compared to literature data. RESULTS: The indications for surgery were compression and/or dislocation of the trachea in 174 (65.9%) patients, hyperthyreodism in 74 (28%) and cosmetic problems in others. The mean hospital stay was 4 days. Thirty-one patients (11.7%) had transient hypocalcaemia, but only 1 (0.3%) was symptomatic, and only 4 (1.5%) had permanent hypocalcaemia. Other complications included hematoma 4 (1.5%), temporary unilateral recurrent laryngeal nerve palsy 7 (2.6%), permanent unilateral laryngeal nerve palsy 2 (0.75%), and seroma in 8 (3%) cases. Incidental thyroid carcinomas were found on hystology in 9 (3.5%) patients. No recurrence was observed during the follow-up. CONCLUSION: Total thyroidectomy may be the procedure of choice for the surgical management of benign multinodular goiter.

Heterogeneous crystal nucleation: the effect of lattice mismatch.

A simple dynamical density functional theory is used to investigate freezing of an undercooled liquid in the presence of a crystalline substrate. We find that the adsorption of the crystalline phase on the substrate, the contact angle, and the height of the nucleation barrier are nonmonotonic functions of the lattice constant of the substrate. We show that the free-growth-limited model of particle-induced freezing by Greer et al. [Acta Mater. 48, 2823 (2000)] is valid for larger nanoparticles and a small anisotropy of the interface free energy. Faceting due to the small size of the foreign particle or a high anisotropy decouples free growth from the critical size of homogeneous nuclei.

Development and Functional Characterization of a Versatile Radio-/Immunotheranostic Tool for Prostate Cancer Management.

Due to its overexpression on the surface of prostate cancer (PCa) cells, the prostate stem cell antigen (PSCA) is a potential target for PCa diagnosis and therapy. Here we describe the development and functional characterization of a novel IgG4-based anti-PSCA antibody (Ab) derivative (anti-PSCA IgG4-TM) that is conjugated with the chelator DOTAGA. The anti-PSCA IgG4-TM represents a multimodal immunotheranostic compound that can be used (i) as a target module (TM) for UniCAR T cell-based immunotherapy, (ii) for diagnostic positron emission tomography (PET) imaging, and (iii) targeted alpha therapy. Cross-linkage of UniCAR T cells and PSCA-positive tumor cells via the anti-PSCA IgG4-TM results in efficient tumor cell lysis both in vitro and in vivo. After radiolabeling with 64Cu2+, the anti-PSCA IgG4-TM was successfully applied for high contrast PET imaging. In a PCa mouse model, it showed specific accumulation in PSCA-expressing tumors, while no uptake in other organs was observed. Additionally, the DOTAGA-conjugated anti-PSCA IgG4-TM was radiolabeled with 225Ac3+ and applied for targeted alpha therapy. A single injection of the 225Ac-labeled anti-PSCA IgG4-TM was able to significantly control tumor growth in experimental mice. Overall, the novel anti-PSCA IgG4-TM represents an attractive first member of a novel group of radio-/immunotheranostics that allows diagnostic imaging, endoradiotherapy, and CAR T cell immunotherapy.

Faceting and branching in 2D crystal growth.

Using atomic scale time-dependent density functional calculations we confirm that both diffusion-controlled and diffusionless crystallization modes exist in simple 2D systems. We provide theoretical evidence that a faceted to nonfaceted transition is coupled to these crystallization modes, and faceting is governed by the local supersaturation at the fluid-crystalline interface. We also show that competing modes of crystallization have a major influence on mesopattern formation. Irregularly branched and porous structures are emerging at the crossover of the crystallization modes. The proposed branching mechanism differs essentially from dendritic fingering driven by diffusive instability.

Amorphous nucleation precursor in highly nonequilibrium fluids.

Dynamical density-functional simulations reveal structural aspects of crystal nucleation in undercooled liquids: The first appearing solid is amorphous, which promotes the nucleation of bcc crystals but suppresses the appearance of the fcc and hcp phases. These findings are associated with features of the effective interaction potential deduced from the amorphous structure.

Phase-Field Modeling of Biomineralization in Mollusks and Corals: Microstructure vs Formation Mechanism.

While biological crystallization processes have been studied on the microscale extensively, there is a general lack of models addressing the mesoscale aspects of such phenomena. In this work, we investigate whether the phase-field theory developed in materials' science for describing complex polycrystalline structures on the mesoscale can be meaningfully adapted to model crystallization in biological systems. We demonstrate the abilities of the phase-field technique by modeling a range of microstructures observed in mollusk shells and coral skeletons, including granular, prismatic, sheet/columnar nacre, and sprinkled spherulitic structures. We also compare two possible micromechanisms of calcification: the classical route, via ion-by-ion addition from a fluid state, and a nonclassical route, crystallization of an amorphous precursor deposited at the solidification front. We show that with an appropriate choice of the model parameters, microstructures similar to those found in biomineralized systems can be obtained along both routes, though the time-scale of the nonclassical route appears to be more realistic. The resemblance of the simulated and natural biominerals suggests that, underneath the immense biological complexity observed in living organisms, the underlying design principles for biological structures may be understood with simple math and simulated by phase-field theory.

Phase-field modelling of the effect of density change on solidification revisited: model development and analytical solutions for single component materials.

In this paper the development of a physically consistent phase-field theory of solidification shrinkage is presented. The coarse-grained hydrodynamic equations are derived directly from the N-body Hamiltonian equations in the framework of statistical physics, while the constitutive relations are developed in the framework of the standard phase-field theory, by following the variational formalism and the principles of non-equilibrium thermodynamics. To enhance the numerical practicality of the model, quasi-incompressible hydrodynamic equations are derived, where sound waves are absent (but density change is still possible), and therefore the time scale of solidification is accessible in numerical simulations. The model development is followed by a comprehensive mathematical analysis of the equilibrium and propagating one-dimensional solid-liquid interfaces for different density-phase couplings. It is shown, that the fluid flow decelerates/accelerates the solidification front in case of shrinkage/expansion of the solid compared to the case when no density contrast is present between the phases. Furthermore, such a free energy construction is proposed, in which the shape of the equilibrium planar phase-field interface is independent from the density-phase coupling, and the equilibrium interface represents an exact propagating planar interface solution of the quasi-incompressible hydrodynamic equations. Our results are in agreement with previous theoretical predictions.

[Oncology PET radiopharmaceuticals in clinic and research in 2020]. / 2020 onkológiai PET-radiogyógyszerei a klinikumban és a kutatásban.

"PET based" molecular imaging has significant role in personalized medicine. New radiopharmaceuticals are continuously introduced into the daily practice of detecting diseases and assessing the effectiveness of therapy. In recent years theragnostic applications have come to the forefront of radiopharmaceutical development. This article discusses, among others, radiopharmaceuticals labelled with 18F and 68Ga isotopes required for the diagnosis of neuroendocrine and prostate tumours, furthermore the inhibitors of the fibroblast activation protein. The increasing variety of metallic radioisotopes (44Sc, 64Cu, 52Mn, 86Y, 89Zr) will help meet the need for new biomarkers and will greatly facilitate the introduction of the new generation of PET radiopharmaceuticals.

Crystal nucleation in the hard-sphere system revisited: a critical test of theoretical approaches.

The hard-sphere system is the best known fluid that crystallizes: the solid-liquid interfacial free energy, the equations of state, and the height of the nucleation barrier are known accurately, offering a unique possibility for a quantitative validation of nucleation theories. A recent significant downward revision of the interfacial free energy from approximately 0.61kT/sigma(2) to (0.56 +/- 0.02)kT/sigma(2) [Davidchack, R.; Morris, J. R.; Laird, B. B. J. Chem. Phys. 2006, 125, 094710] necessitates a re-evaluation of theoretical approaches to crystal nucleation. This has been carried out for the droplet model of the classical nucleation theory (CNT), the self-consistent classical theory (SCCT), a phenomenological diffuse interface theory (DIT), and single- and two-field variants of the phase field theory that rely on either the usual double-well and interpolation functions (PFT/S1 and PFT/S2, respectively) or on a Ginzburg-Landau expanded free energy that reflects the crystal symmetries (PFT/GL1 and PFT/GL2). We find that the PFT/GL1, PFT/GL2, and DIT models predict fairly accurately the height of the nucleation barrier known from Monte Carlo simulations in the volume fraction range of 0.52 < varphi < 0.54, whereas the CNT, SCCT, PFT/S1, and PFT/S2 models underestimate it significantly.

Successful treatment of a septic aneurysm due to Salmonella enteritidis complicated by the rupture of the pelvis of the kidney.

We report on a 43-year-old patient with septic aneurysm complicated by rupture of the pelvis of the kidney due to Salmonella enteritidis that we treated successfully by empiric therapy, then targeted antibiotic therapy and late surgical intervention with iliofemoral crossover bypass grafting and aneurysm resection. The course was complicated by deep neutropenia and chronic hepatitis C infection.

Hydrodynamic theory of freezing: Nucleation and polycrystalline growth.

Structural aspects of crystal nucleation in undercooled liquids are explored using a nonlinear hydrodynamic theory of crystallization proposed recently [G. I. Tóth et al., J. Phys.: Condens. Matter 26, 055001 (2014)JCOMEL0953-898410.1088/0953-8984/26/5/055001], which is based on combining fluctuating hydrodynamics with the phase-field crystal theory. We show that in this hydrodynamic approach not only homogeneous and heterogeneous nucleation processes are accessible, but also growth front nucleation, which leads to the formation of new (differently oriented) grains at the solid-liquid front in highly undercooled systems. Formation of dislocations at the solid-liquid interface and interference of density waves ahead of the crystallization front are responsible for the appearance of the new orientations at the growth front that lead to spherulite-like nanostructures.

Antioxidants in the egg yolk of a wild passerine: differences between breeding seasons.

Carotenoids and fat-soluble vitamins play crucial roles in several physiological processes. Yolk carotenoid composition may be influenced by the bird's dietary intake and by the possible discrimination during carotenoid metabolism. Information regarding the pigment composition of passerine eggs is very limited. In the present 2-year study, we determined the carotenoid and vitamin concentrations and the percentage profile of carotenoid components in collared flycatcher (Ficedula albicollis) eggs. The major carotenoid was lutein in both years, followed by cis-lutein, zeaxanthin and beta-carotene as other significant components. Carotenoid concentration was higher in 2000 than in 2001. As caterpillar abundance and ambient temperature was lower in 2001 than in 2000, we suggest that the decreased availability of carotenoid-rich resources and the elevated antioxidant demand of the female restricted the carotenoid allocation to the eggs. Our study is the first to indicate that the concentration and profile of yolk carotenoids may considerably vary in the same wild bird population between breeding seasons with different environmental conditions. Compared to other birds, the yolk of this species was relatively rich in vitamins A and E. Vitamin E concentration was positively correlated with total carotenoid concentration, which may be beneficial for the nestlings as these antioxidants synergistically provide better protection.