Mexico and the countries of the Visegrad Group (V4: the Czech Republic/Czechia, Hungary, Poland, and Slovakia) are geographically distant countries. However, both parties share similar characteristics and problems. Although Mexico is the second-largest trading partner of the V4 states in the Americas, following the United States (US), their cooperative relations remain rather tenuous, despite the considerable potential for expansion. This paper pursues four objectives. First, it examines the current state of cooperative relations between Mexico and the V4. Second, it investigates the problems and challenges shared by both parties. Third, it analyzes Mexico’s relations with the European Union (EU), particularly since the entry into force of the Global Agreement - formally titled the Economic Partnership, Political Coordination and Cooperation Agreement between the European Community and its Member States, of the one part, and the United Mexican States, of the other part. Fourth, it identifies the variables that hinder the further development of cooperation between Mexico and the V4. The research hypothesis assumes that Mexico and the V4 countries are highly dependent on their geographically proximate political and economic powers, which, to some extent, constrains the deepening of Mexico-V4 relations. Moreover, these relations are primarily grounded in economic links and in cooperation based on “soft power” capacities, particularly in the scientific and academic spheres.

The dismissals of the court presidents have been an issue of considerable controversy in several European jurisdictions, notably in the Visegrad Group countries (Czechia, Hungary, Poland, and Slovakia). On the one hand, these actions might be perceived as a potential threat to the independence of the judiciary. Still, on the other hand, the premature termination of the court president’s mandate may prove necessary under certain circumstances. The article explores the common problems that have arisen in the V4 states and the guarantees stemming from Article 6(1) of the European Convention on Human Rights. It provides an insight into the domestic removal mechanisms. Based on the existing ECtHR case-law, the positive duties of the States are further reconstructed with regard to the dismissals of the court presidents. The article also includes several proposals for solving specific problems that the Court has not directly addressed. Furthermore, it lists the criteria to be met by the High Contracting Parties so that the national practices regarding dismissal proceedings fully comply with the Convention.

This article examines China's geopolitical interests in the Visegrád Four (V4) countries within the context of great-power rivalry. The study highlights how the ongoing global crisis has reshaped bilateral and multilateral relations, with the European Union (EU) emerging as a significant focus of China's strategic influence. The V4 countries, Poland, the Czech Republic, Slovakia, and Hungary, have become especially relevant due to their industrial capacities, relatively recent EU membership, and geographical location on the EU's eastern borders.The research reviews previous studies on China's influence in Europe, including soft-power initiatives such as the Belt and Road Initiative (BRI), foreign investments, and trade relations. It explores how various political dynamics within V4 states have affected their stance towards China, noting Poland's cautious engagement, the Czech Republic's increasing alignment with Western allies, Slovakia’s political shifts, and Hungary’s deepening partnership with Beijing. Additionally, the article investigates China’s role in Europe's green energy and digital infrastructure, assessing the implications of economic dependencies.The findings suggest that while China perceives V4 countries as gateways into Europe, geopolitical shifts, including the EU’s Global Gateway Initiative and growing concerns over technological security, challenge Beijing's strategies, prompting V4 countriesto reconsider their engagement with China and seek alternative partnerships aligned with EU and NATO frameworks. Ultimately, the study underscores the dual pressures faced by V4 states as they navigate economic opportunities from China and political commitments within the EU and NATO.

Abstract The Visegrad Group (V4), a unique subregional cooperation within the European Union, has experienced a negative shift following the Russian aggression in Ukraine. The Russian aggression in Ukraine also triggered another development in the EU. Enlargement has been halted since 2013 and has become the centre of attention again. The official candidate status was granted swiftly to Ukraine, Moldova, and Georgia, which also put the Western Balkans’ future in the spotlight. This article aims to interpret the four Visegrad states’ positions on the EU’s enlargement policy and alterations in these by looking for explanatory causes in the 2014–2025 period. Enlargement is of high relevance in the region, not only because of the V4 countries’ accession to the EU twenty years ago and of its complex, sometimes conflictual interactions with the EU institutions since then but also because the candidate countries are located in the immediate neighbourhood of the V4 region, that brings the geopolitical aspects of the policy in the spotlight. After conceptualizing the V4, process tracing methodology is applied to answer the question of the V4 states’ view and influence on the enlargement policy of the EU. This article aims not to determine the future perspectives of the European Union’s overall enlargement policy but to focus solely on the Visegrad countries. Still, the conclusions of this article can contribute to the general understanding of the debates on the future of enlargement.

This article investigates the strategic culture responses of the Visegrád Four (V4) states to the 2022 Russia–Ukraine war. Building on the theoretical foundation laid by Jeffrey Lantis, it examines the evolution of strategic culture, particularly how external shocks prompt significant shifts or maintain continuity in state behaviour. By exploring the specific cases of Czechia and Slovakia, where substantial transformation in strategic culture was observed, and contrasting these with the relative continuity in Poland and Hungary, the study contributes to broader debates on the adaptability of strategic culture and the critical role of individual agency in both continuity and change.

Vanadium pentoxide (V2O5) has shown great potential as the electrode for aqueous ammonium ion batteries (AAIBs) owing to its good electrochemical reversibility and high theoretical capacity. However, the electrochemical performance of V2O5 is seriously limited by the weak NH4+ adsorption capability and insufficient active sites of vanadium oxide originated from the unsuitable 3d orbital electron state. Herein, the strategy of a 3d orbital electron tunning and crystal engineering is used to increase the ammonium ion storage capacity of V2O5 electrode. The experimental results show that the modified 3d orbital state of V4+ (t2g1) can effectively increase the active sites of V2O5. Therefore, the as-prepared N-VO exhibits a high specific capacity of 249.3 mA h g−1 at 1.0 A g−1 and 69.5 mA h g−1 at 10.0 A g−1, superior to other reported anode material for AAIBs. Noticeably, the prepared resultant quasi-solid-state ammonium ion battery can display considerable cycling stability with capacity retention of 87.9% after a long cycle life of 10 000 cycles at 1 A g−1 and impressive mechanical flexibility with no capacity decay after cycling at different bending angles.

This study examines the political determinants of restrictive immigration policies in the Visegrad Group (V4) countries—Czech Republic, Hungary, Poland, and Slovakia—between 2014 and 2019, focusing on ideological positions, parliamentary power, nationalism, economic concerns, and security considerations of political parties. Following the 2015 migration crisis, the V4 nations adopted a notably restrictive stance on immigration, diverging from Western European policies. While existing research highlights nationalism and populism, limited empirical analysis systematically assesses political party dynamics influencing immigration policy. To address this gap, this study employs a quantitative research design, utilizing descriptive and econometric analysis of the Chapel Hill Expert Survey (CHES) data. Findings indicate that right-wing and nationalist parties, particularly those with strong parliamentary representation, are key drivers of restrictive policies. Additionally, economic concerns and security narratives further reinforce anti-immigration stances. The study contributes to broader discussions on EU governance, emphasizing the role of domestic politics in shaping migration policy. The results demonstrate the importance of more balanced, inclusive immigration strategies that reconcile security, economic stability, and social cohesion. Policy recommendations suggest that the EU should focus on addressing political and ideological factors, promote dialogue and cooperation between V4 and Western EU states, and enhance public education to counter nationalist rhetoric and shape more balanced immigration policies.

Aim. To investigate functional state of mitochondria and mitochondrial DNA (mtDNA) polymorphism in coronary artery disease (CAD) patients with life-threatening cardiac rhythm disorders (CRD).Methods. We investigated venous blood samples of 45 patients with uncomplicated CAD and 120 CAD patients with CRD. Oxygen consumption rate of mitochondrias of leukocytes in V3 and V4 states were determined in pyruvate-malate and succinate buffers, as well as in the presence of palmitic acid (PA). In patients with complicated CAD, mtDNA haplogroup and substitutions in gene encoding proteins of the respiratory chain complexes and mitochondrial rRNA were determined. Statistical analysis was performed using Mann-Whitney, Wilcoxon tests and Chi-square test with Yates’ correction.Results. In CAD and CAD with CRD, oxygen consumption rate of intact mitochondria did not different in either pyruvate-malate or succinate buffers. In uncomplicated CAD, PA supplementation increases oxygen consumption rate by mitochondria in both succinate and pyruvate-malate buffers. The majority of patients (41%) with CAD and CRD were carriers of the haplogroup «H» and, in this indicator, the sample did not differ from patients with uncomplicated CAD. However, mtDNA of patients with complicated CAD was characterized by a more frequent combined carriage of two and more missense substitutions in genes of respiratory chain and rRNA.Conclusion. Mitochondria of patients with coronary artery disease and life-threatening cardiac rhythm disorders have reduced functional reserve. The distribution of frequencies of main mtDNA haplogroups of patients with coronary artery disease with life threatening cardiac rhythm disorders corresponds to the population. The mtDNA of such patients is characterized by a high frequency of carriage of combined polymorphisms in gene of electron transport chain proteins and rRNA.

Herein, by introducing a VO2+ group into the microstructure of phosphomolybdenic acid (PMA) and loading it onto MOF-808, a series of composite catalysts were obtained by reducing the V element with Vitamin C (ascorbic acid). V atoms exist in the secondary structural units of phosphomolybdic acid as [VO(H2O)5]H[PMo12O40]. Surprisingly, the VC-VO-PMA/MOF-808 completely removed DBT and 4,6-DMDBT from the simulated oil in 12 min. The EPR and XPS results verify the electronic structure and valence state of V4+ in the composites. The oxygen vacancy and V4+ generated by VC modification in VC-VO-PMA/MOF-808 have positive effects on the oxidation desulfurization (ODS) activity. Based on the design of the microstructure and electronic structure, this study provides a new paradigm for the development of readily available and efficient ODS catalysts.

An easily accessible and efficient catalyst is highly promising for the cleavage of the C–C bond and C–O bond of β–O–4 lignin model compounds. In this work, ionic liquid [Bim][Pic] (Bim = 1-butyl imidazolium, Pic = picolinate anion)-stabilizing vanadium oxo-cluster catalysts were constructed conveniently for selective aerobic oxidation to cleave the β–O–4 linkages into phenols, eaters and acids. The as-synthesized vanadium oxo-cluster catalysts Bim-V-n (n = 1–3) were characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), electron paramagnetic resonance (EPR), mass spectrometry (MS), and elemental analysis. The vanadium in the catalyst exists stably in a mixed-valence state of V4+ and V5+. Molecular oxygen was activated through the mutual transformation of V4+ and V5+ to form superoxide free radicals, which were captured by the EPR spectrum. Especially, Bim-V-2 afforded superior catalytic activity under aerobic conditions (10 h, 120 °C). The highly reversible interconversion of V4+ and V5+ species in vanadium oxo-cluster allowed the coexistence of the mixed-valence vanadium species, which was responsible for oxidizing β–O–4 alcohols to β–O–4 ketones. Moreover, superoxide free radicals can facilitate the cleavage of C–C and C–O bonds in β–O–4 ketones. Especially, 1-butyl imidazolium also played a positive role in the cleavage of C–O bonds by the action of the cation protons. No appreciable loss of catalytic activity was observed, and the catalyst could be recovered and reused up to five times, reflecting the excellent recyclability of the present vanadium oxo-cluster catalysts. The catalytic system can be extended for the cleavage of the C–C bond and C–O bond of β–O–4 of the other lignin model compounds, and the reaction could still be completed efficiently. This provides a new perspective for the selective aerobic oxidation of β–O–4 lignin without co-catalysts.

Abstract Rechargeable, cost‐efficient aqueous aluminium‐ion batteries (AAIBs) possess abundant trivalent charge carriers with high volumetric energy densities. However, the rapid and irreversible formation of Al2O3 passivation films on aluminium‐ion (AI) anodes while using aqueous electrolytes limits their development. Herein, Zn metal was used as the anode, and Al3+ was locally deposited on the Zn anode during charging. V6O13 with a mixed vanadium state of V4+/V5+ was chosen as the cathode because of its efficient ion diffusion (solid state) and high electron conductivity. The Zn−Al/3 M Al(OTF)3/V6O13 cell exhibited high current density and excellent long‐term cycling stability, demonstrating a very high specific capacity of ∼100 mAh g−1 at a current density of 3 A g−1 and Coulombic efficiency of ∼100 % with reversible stability over 1400 cycles. Furthermore, the V6O13 cathode exhibited a multi‐ionic capacity of Zn2+‐ and H+‐ions during the Al deposition/dissolution reaction in AAIBs, demonstrating high safety and stability for fast charging.

Rare earth metal based DES assisted the VPO synthesis for n-butane selective oxidation toward maleic anhydride

Abstract This article examines the unemployment policy of Central-East-European countries applying mixed methods. First, fuzzy set analysis is used to determine the efficiency of unemployment measures for reducing the poverty gap. Three causal conditions are measured: the net replacement rate of unemployment benefits, labour law regulations related to job security, and public spending on labour-market programs. This analysis reveals two possible pathways: governments may either provide a high level of job security, or spend on active and passive labour-market measures. Second, the fuzzy set analysis was completed with a comparative legal analysis covering the Visegrad countries that examined the policy choices the Visegrad countries made after the economic crisis. The paper argues that due to the different approaches to the welfare state, any potential EU initiatives for regulating unemployment benefits under the European Pillar of Social Rights might put divergent adaptation pressure on the V4 states. The differences are significant, as they would not only challenge effective social integration but also hamper the envisioned political cooperation of the V4 countries in this policy area. Building on previous literature, this paper is written to contribute to research on the European Social Model and social integration within the European Union.

Real property tax belongs to traditional taxes, often imposed as a local tax. The same applies to V4 countries (Slovakia, Czech Republic, Hungary, Poland), however, the budgetary significance of its revenues differs across these states and so does their approach to its regulation. In this research article, the authors deeper analyse the budgetary significance of the tax in particular V4 states in terms of selected criteria (ratio to GDP, other local taxes, tax and total revenues of local government), and then the legal regulation of the tax applied in these states in the context of its current and potential impact on acquired tax revenues. The data shows that the overall revenues of the tax in comparison with the total revenues of local government do not represent a significant value, however, from the viewpoint of municipal budgets, research on the tax potential is justified as it is the most important local tax in three of the states. We found that the budgetary significance of real property tax differs among the V4 countries with the highest importance in Poland. Based on the legislation analysis, we identified differences among V4 members, with the greatest potential for legislative improvements in the countries with lower tax revenues. The results of the research may create the basis for further research of the tax potential in V4 countries as well as for application practice (besides pro futuro legislative changes, more efficient tax collection and more objective real estate taxation).

Herein, we report high electrocatalytic activity of monoclinic VO2 (M1 phase) for the oxygen evolution reaction (OER) for the first time. The single-phase VO2 (M1) nanoparticles are prepared in the form of uniformly covering the surface of individual carbon fibers constituting a carbon fiber paper (CFP). The VO2 nanoparticles reveal the metal-insulator phase transition at ca. 65 °C (heating) and 62 °C (cooling) with low thermal hysteresis, indicating a high concentration of structural defect which is considered a grain boundary among VO2 nanoparticles with some particle coalescence. Consequently, the VO2/CFP shows a high electrocatalytic OER activity with the lowest η10 (350 mV) and Tafel slope (46 mV/dec) values in a 1 M aqueous solution of KOH as compared to those of the vacuum annealed V2O5 and the hydrothermally grown VO2 (M1), α-V2O5, and γ′-V2O5. The catalytically active site is considered V4+ components and V4+/5+ redox couples in VO2. The oxidation state of V4+ is revealed to be more favorable to the OER catalysis compared to that of V5+ in vanadium oxide through comparative studies. Furthermore, the amount of V5+ component is found to be increased on the surface of VO2 catalyst during the OER, giving rise to the performance degradation. This work suggests V4+ and its redox couple as a novel active component for the OER in metal-oxide electrocatalysts.

The article’s focus is on the postal services sector. The sector plays an important role in a process of delivering packages to the customers. Over the last few years, there has been a significant growth in volume of shipments transported. The aim of the article is to demonstrate the current development and subsequent prediction of two selected indicators that play an important role in the context of e-commerce development in the V4 states. One of the indicators is the number of shipments; the other is the indicator of CO2 emissions. While the values of the CO2 emission in the predictive analysis in comparison with the growing e-commerce turnover indicator stagnate, the number of shipments is growing alongside the e-commerce turnover values. In the light of these findings, it is clear that the growing number of shipments will result in the need to change the approach to the organisation of the parcel delivery process, especially in big cities and agglomerations. It is also necessary to mention that organisational changes in the parcel delivery process in big cities and agglomerations must be carried out in an environmentally friendly way.

Abstract The migration policies of the V4 countries present many similarities that seem to be the effect of congruent historical and economic determinants. During the migration crisis in 2015–2016, the Visegrad states partially coordinated their political communication using the same communication panels, which strongly impacted domestic political relations. The V4’s approach was a refusal of the open-door policy promoted by Germany and Sweden, and the European Union. Our main findings are that the migration crisis strengthened the cohesion among V4 countries, although the source of this cohesion was clearly a populistic stance toward the possible implications of uncontrolled migration (migrants and refugees). This communication style and the resulting political tensions were reflected in the V4 states’ resentment based on a sense of shared historical experiences rooted in Central European location and shared experience of the repercussions of communism. In this sense, a strong commitment to the idea of a sovereign nation-state, and a reluctance towards postmodern values are also important factors. This study charts the changes in V4 migration policy since 2015, highlighting the crucial developments in V4 countries’ negotiations with the European Union. It also deals with the foreign and domestic effects of the migration crisis and the V4 states’ discourse of migration, which was complemented by a debate on the future of the EU that became especially important in Hungary and Poland.

ABSTRACT Electronic states in solid-solution transition metal oxides may differ from those in their parent compounds, and this results in interesting electronic properties. In this study, the valence states and electronic properties of solid solutions of (1 − x)PbVO3− xBiCrO3 are reported. The solid solutions are successfully synthesized under high-pressure and high-temperature conditions of 5 GPa or 7 GPa and 1273 K, respectively. A change in the crystal structure from centrosymmetric monoclinic (C2/c), as in BiCrO3, to polar tetragonal (P4mm), as in PbVO3, is observed. A tetragonal-to-cubic phase transition, which results in a negative thermal expansion, was observed in 7/8PbVO3-1/8BiCrO3 at approximately 700 K. X-ray absorption spectroscopy and magnetic studies reveal that the Cr and V atoms are in the valence states 3+ and 4+, respectively, which are the same as those of the parent compounds. Thus, it was concluded that the valence state of V4+/Cr3+ and the electron localization in the (1 − x)PbVO3− xBiCrO3 solid solutions are considerably robust.

ABSTRACT The four Central and Eastern European (CEE) states, namely Poland, the Czech Republic, Hungary, and Slovakia, known as the Visegrad Group (V4), belong to the multilateral China-led 17 + 1 subregional platform that seeks to upgrade its members’ mutual economic and transportation infrastructure ties. This comparative case study traces the V4 states’ relations with China since the outbreak of the Covid-19 pandemic in Europe and explores how far the existing multilateral format 17 + 1 was able to utilize its potential for strengthening China’s presence through healthcare cooperation to work together in fighting the pandemic. The findings reveal the prevailing bilateral ties being preferred over the institutionalized multilateral platform 17 + 1, a sustained ambiguity in the CEE states’ relations with China, and a poor coherence of the 17 + 1 format.

Abstract The topic of energy is still one of the most sensitive policy areas. The aim of this article is to examine the multi-level governance and energy specifics of the V4 countries within the context of European integration by analyzing selected the specifics of the energy mix of the V4 group countries. This will be carried out within the context of applying the theory of multilevel governance. The paper shows how energy policy is formed at state, and/or non-state level, as well as how these levels are influenced by the EU. The article also looks at the efforts taken to shape a common energy policy. A closer examination of the individual countries‘ levels lies outside the scope of this article. Therefore, the framework was chosen with regard to the particular features within the context of the functioning of the V4 group of countries. Using multi-level governance as a theoretical concept, the authors considered the limits arising from the determination of levels and the subjects of the survey, as well as having distinguished three levels of analysis. The first is the supranational level. This is represented by the EU. The second level is represented by the V4 states. The third level is the state as the actor that formulates energy policy, sets the energy mix and subsequently manifests itself in relation to the EU and the V4 group. Energy policy is significantly influenced by states, especially in the area of energy security of fuel supplies, or that of setting the energy mix. With the gradual communitarization of energy policy, the EU’s influence is growing and it is debatable how the evaluation of existing strategic plans, presented by individual states, will be done. The role of the V4 group is the weakest of the three levels of analysis which were examined. However, its increasing influence can be predicted mainly in the case of coal depletion and the perception of nuclear energy as a renewable source.