Relative Stability Research Articles

Relative Stability and Basicity of Enamines from Aminocatalysts

Relative Stability and Basicity of Enamines from Aminocatalysts

Conformational Switching of a Nano-Size Urea-Bridged Zn(II)Porphyrin Dimer by External Stimuli.

For the first time, explicit stabilization of all the three conformers, viz. (cis,cis), (cis,trans) and (trans,trans), of a 'nano-sized' highly-flexible urea-bridged Zn(II)porphyrin dimer have been achieved via careful manipulations of external stimuli such as solvent dielectrics, temperature, anionic interactions, axial ligation and surface-induced stabilization. The conformers differ widely in their structures, chemical and photophysical properties and thus have vast potential applicability. X-ray structural characterizations have been reported for the (cis,cis) and (cis,trans)-conformers. While (cis,cis) conformer stabilized exclusively in dichloromethane, more polar solvents resulted in the stabilization of (cis,trans) and (trans,trans)-conformers. Low temperature promotes the stabilization of (cis,trans)-conformer while rise in temperature facilitates flipping to the (cis,cis) one. Significantly, exclusive stabilization of the (trans,trans)-isomer has been illustrated using acetate anion which facilitates H-bonding with the two amide linkages of the urea spacer. Remarkably, HOPG surface facilitates stabilization of the energetically challenging (trans,trans)-conformer via CH⋅⋅⋅π and π⋅⋅⋅π interactions with the solid surface to the porphyrinic cores. DFT calculations demonstrate that the relative stability of the conformers can be modulated upon slight external perturbations as also observed in the experiment. Several factors contributing towards the conformational landscape for the highly flexible urea-bridged porphyrin dimers have been mapped.

The Distribution of Land in Luxembourg (1766–1872): Family-Level Wealth Persistence in the Midst of Institutional Change

The paper analyzes family-level wealth inequality and social mobility in Dudelange (Luxembourg) over five generations between 1766 and 1872, a period that saw the end of feudal social relations. While the integration of Luxembourg into the French revolutionary regime produced a reduction in the Gini coefficient for the ownership of land, the social mobility analysis reveals a relative stability of family positions within the land-wealth distribution throughout the period. This shows that family-level transmission mechanisms limit social mobility and strongly advantage those with ancestors owning property wealth, even when there are significant changes in the organization of property relations.

Isomerism in Phenyl 2‐Pyridyl Ketoxime Metal Complexes

AbstractThe octahedral complex [RhCl2(ppkoH)(ppko)] (1) was obtained from the reaction between RhCl3 and phenyl 2‐pyridyl ketoxime (ppkoH). Attempts to prepare the corresponding octahedral platinum compound from K2PtCl6 gave instead the square planar [Pt2+(ppko)2] (2), but when the halogen was changed to bromine, the octahedral [Pt4+Br2(ppko)2] (3) was formed. The crystal structures were determined by X‐Ray crystallography. All the compounds have two N,N‐chelating oxime ligands. In 1, one of them is deprotonated, while in 2 and 3 both ligands are deprotonated. Compounds 1 and 3 have two halogen ligands in trans position. In 1 the oxime groups are situated mutually in cis position with an intramolecular hydrogen bond between the two N−O(H) groups. The formation of 2 involves reduction of the platinum metal and the complex has oximes in trans position to each other. Compound 3 has an all‐trans geometry. Since octahedral and square planar compounds have a possibility to isomerism, we studied the relative stability of different geometries by DFT calculations. A mixture of isomers is likely to be formed in the reactions, but the most stable form was found to crystallize. The properties of the electron density in the preferred isomers were also investigated via QTAIM methods.

Changes in Adolescent Heterosexual Behaviors from the 1980s to the Present in Various Western Countries: A Systematic Review

Adolescence is a stage of significant intrapersonal and interpersonal changes, influenced by cultural and historical shifts. This study aims to analyze the changes in heterosexual behaviors among adolescents in Western countries over the past 50 years approximately. For this purpose, we conducted a systematic review following the PRISMA model, utilizing the online databases EBSCO, WoS, and Scopus, covering the period from 1980 to 2024, across ten European countries. The review focused on studies published in scientific journals with regional or national samples. In addition to the 30 selected studies, three more were included due to their relevance as cited in the selected articles. Despite the considerable methodological heterogeneity, the results showed a relative stabilization of the differences in sexual behaviors of boys and girls throughout time. Those differences were more evident in Southern European countries. Some changes were also noted, such as the delay in the initiation of the first sexual intercourse, a trend observed over the last decade. The findings are discussed in terms of the sexual script theory, highlighting the importance of these mental frameworks in the heteronormative sexual socialization of boys and girls. Future research should emphasize the diversity of heterosexual behaviors, their significance, and the emotional experiences that accompany them.

Comparative Outcomes of Percutaneous K-Wires Versus Plate Fixation in the Treatment of Distal Radius Fractures: A Focus on Stability in Osteoporotic Patients and Both-Bone Distal End Fractures.

Background Distal radius fractures (DRFs) are commonly treated with percutaneous K-wire or plate fixation. The relative efficacy and stability of these methods, particularly in osteoporotic patients and in cases involving both distal radius and ulna fractures, remain subjects of clinical debate. Objective This study aims to compare the outcomes of percutaneous K-wire fixation versus plate fixation in patients with distal end radius fractures, focusing on postoperative stability in osteoporotic conditions and both-bone distal end fractures. Methods A total of 50 patients were retrospectively analysed and divided into two groups: 25 underwent percutaneous K-wire fixation, and 25 underwent plate fixation. Outcomes measured included bone healing time, complication rates, functional recovery using the DASH score, and radiological outcomes through standard X-ray imaging. Results Preliminary data suggest that plate fixation offers better stability, especially in osteoporotic patients and cases with both-bone involvement. Complications with K-wire fixation were more frequent in these subgroups. Conclusion Plate fixation may provide superior stability and functional outcomes in treating DRFs, particularly in complex cases involving osteoporosis or bone injuries. Further research with larger sample sizes and prospective design is recommended.

Radiocarbon dating and isotopic paleoecology of Notiomastodon platensis (Mammalia: Proboscidea) from the late Pleistocene of Minas Gerais, Brazil

Proboscidea is a group of large mammals abundant in the fossil record and in Brazil it is represented by Notiomastodon platensis (Ameghino, 1888). To improve the understanding on its taxonomy, chronology, annual diet, and habitats paleoenvironmental aspects, we conducted a morphological description, absolute dating, and analysis of stable isotopes of carbon and oxygen (δ13C and δ18O) in Notiomastodon' remains from the northern (Norte de Minas) and western (Triângulo Mineiro) mesoregions of Minas Gerais State, Brazil. The material includes isolated teeth, mandibular portions, and postcranial bones at different levels of fragmentation, associated with at least eight adults and one juvenile. The only individual from Triângulo, found in Campina Verde municipality, was dated at 27,715–27,903 Cal yr BP. It presented a mixed diet based on C4 plants (piC4 = 90 %; δ13C = 0.5 ‰), which implies the occupation of an open environment, mostly pasture. The region was relatively humid (δ18O = 24.7 ‰), which is supported by the existence of humidity corridors in the Amazon region. A similar phytophysiognomy was inferred for the Norte de Minas region between at least 21,966–22,279 Cal yr BP and 18,944–19,157 Cal yr BP. However, one specimen showed a different δ13C value (piC3 = 0.87 %; δ13C = −10.2 ‰). This indicates it lived in a transitional environment between low-density forest and arboreal savannah. This likely occurred during a period that favored the expansion of trees and shrubs. The region underwent climate change, from relatively humid conditions (δ18O = 25.6 ± 0.2 ‰) to expressively dry (δ18O = 34.6 ‰) between the dated periods, a change corroborated by some palynological data. The multiannual paleoecological analysis, based on sequential sampling of three dentin layers of an incisor, indicated the relative stability of vegetation and climate despite fluctuations in hydrology. The perceived disassociation between vegetation dynamics and local hydrology corroborates the idea that factors other than precipitation may play a significant role in the environmental dynamics of the Cerrado biome.

Treating Cognition in Schizophrenia: A Whole Lifespan Perspective

Background/Objectives: Cognitive impairment is a core feature of schizophrenia, affecting attention, memory, and executive function and contributing significantly to the burden of the disorder. These deficits often begin before the onset of psychotic symptoms and persist throughout life, making their treatment essential for improving outcomes and functionality. This work aims to explore the impact of these impairments at different life stages and the interventions that have been developed to mitigate their effects. Methods: This narrative review examined literature searching for different approaches to treat cognitive impairments in schizophrenia across the lifespan. Results: Cognitive alterations appear before psychosis onset, suggesting a window for primary prevention. Then, a period of relative stability with a slight decline gives the period to secondary and eventually tertiary prevention for more than two decades. Finally, another window for tertiary prevention occurs from the third decade of illness until the later stages of the illness, when a progression in cognitive decline could be accelerated in some cases. Cognitive remediation and physical exercise are evidence-based interventions that should be provided to all patients with disabilities. Conclusions: Treating cognition throughout the whole lifespan is crucial for improving functional outcomes. It is necessary to consider the need for personalized, stage-specific strategies to enhance cognitive function and functioning in patients.

Evaluating Electronic Properties of Self‐Assembled Indium Phosphide Nanomaterials as High‐Efficient Solar Cell

ABSTRACTGeometries and electronic properties associated with relative stabilities and energy gaps of porous (InP)12n (n = 1–12) nanoclusters (NCs) (nanowires and nanosheets) are systemically studied by density functional method. The relative stabilities of (InP)12n NCs through the calculated fragmentation energies and cluster‐binding energies are determined and discussed. Interestingly, the calculated energy gaps of (InP)12n nanowires and nanosheets are localized at regions of visible light energy ranges. (InP)12n are relatively wide‐band semiconductor solar energy nanomaterial. The calculated density of states reveals large‐sized porous (InP)12n nanosheets and nanowires with narrow pore size distribution and slight thickness and a large surface area manifest ultrahigh specific capacitance of trapping solar light energies and high light‐to‐electricity conversion efficiencies in solar energy absorption or conversion or photovoltaicsm. Particularly, (InP)12n NCs maintain their elemental properties of individual (InP)12 clusters in the energy gaps of (InP)12n (n > 4). NCs are almost independent of variable sizes. Specifically, the size‐dependent charge transfers of In atoms in (InP)12n NCs exhibit that ionic and covalent bonding exist in (InP)12n NCs and can stabilize (InP)12n NCs. Comparison with experiment results available is made.

Design and synthesis of naphthalimide-based CO fluorescent probes realizing tricolor detection and turn-on/off response

Carbon monoxide (CO) fluorescent probes have attracted tremendous attention attributed to their low detection limit, high specificity, simple operation and good biocompatibility. However, the relationship between the molecular structure and the fluorescence response signal still needs to be systematically elucidated for different applications. Herein, three different CO fluorescent probes based on naphthalimide derivative with blue emission (B-NIA), green emission (G-NIA), and near-infrared emission (R-NIA) were designed and synthesized. Three-primary colors and opposite turn-on or turn-off fluorescent responses to CO were achieved by regulating the conjugation system of fluorophores and the position of fluorescent recognition group. The change of fluorescence response and sensing mechanism for CO detection was studied by theory calculation and mass spectrometry analysis. All the B/G/R-NIA possessed high sensitivity for CO detection. Notably, the R-NIA emerged with a noticeable NIR fluorescence response to CO with a low detection limit (0.61 µM) and high selectivity and relative pH stability. In addition, the R-NIA showed particularly low cytotoxicity and has been successfully used to detect CO in living cells. These studies provided the theoretical reference and technical route to synthesize fluorescent probes with different emission wavelengths and opposite fluorescent responses to CO for various application scenarios

Interindividual Similarity of the Spatial Organization of the EEG: an Ontogenetic Study

In this study took part 39 adult subjects, 28 children 12 years old, 21 children 8–9 years old, 26 children 5–6 years old and 19 newborns. In each age group, the coefficient of interindividual similarity (CIS) of the spatial organisation of the electroencephalogram (EEG) was calculated using Pearson's crosscorrelation algorithm. Results reveal high level of interindividual similarity of spatial structure of EEG distant connections. Both in adults and children CIS exceeded 0.80. In women, compared with men, a significantly higher level of interindividual similarity of the spatial organization of the EEG was revealed for all studied combinations of EEG connections. The obtained data shows that relative stability in ontogenesis of the spatial structure of dynamic activity of the cortex is apparently provided mainly through determined by a genotype distant intra- and interhemispheric interconnections that forming certain morfofunctional “skeleton” of neocortex. The functionally specific interactions realizable across more plastic “local chains” of near intercortical interrelations are carried out on basis of the dynamic activity of the brain hemispheres that ordered by means of such “global” interactions. Such system organization of intercortical interactions can provide both safety of individual properties of personality and the ability of the brain to effectively adapt to various influences of environment at phenotype formation in ontogenesis.

The Rise and Fall of the Teaching Profession: Prestige, Interest, Preparation, and Satisfaction Over the Last Half Century

We examine the state of the U.S. K–12 teaching profession over the last half century by compiling nationally representative time-series data on four interrelated constructs: occupational prestige, interest among students, the number of individuals preparing for entry, and on-the-job satisfaction. We find a consistent and dynamic pattern across every measure: a rapid decline in the 1970s, a swift rise in the 1980s extending into the mid-1990s, relative stability, and then a sustained decline beginning around 2010. The current state of the teaching profession is at or near its lowest levels in 50 years. We identify and explore a range of hypotheses that might explain these historical patterns including economic and sociopolitical factors, education policies, and school environments.

The Operando Nature of Isobutene Adsorbed in Zeolite H-SSZ-13 Unraveled by Machine Learning Potentials Beyond DFT Accuracy.

Unraveling the nature of adsorbed olefins in zeolites is crucial to understand numerous zeolite-catalyzed processes. A well-grounded theoretical description critically depends on both an accurate determination of the potential energy surface (PES) and a reliable account of entropic effects at operating conditions. Herein, we propose a transfer learning approach to perform random phase approximation (RPA) quality enhanced sampling molecular dynamics simulations, thereby approaching chemical accuracy on both the determination and exploration of the PES. The proposed methodology is used to investigate isobutene adsorption in H-SSZ-13 as prototypical system to estimate the relative stability of physisorbed olefins, carbenium ions and surface alkoxide species (SAS) in Brönsted-acidic zeolites. We show that the tert-butyl carbenium ion formation is highly endothermic and no entropic stabilization is observed compared to the physisorbed complex within H-SSZ-13. Hence, its predicted concentration and lifetime are negligible, making a direct experimental observation unlikely. Yet, it remains a shallow minimum on the free energy surface over the whole considered temperature range (273--873 K), being therefore a short-lived reaction intermediate rather than a transition state species.

Empirical Analysis of Stability of An+1BnO3n+1 Ruddlesden–Popper Phases Using Reciprocal n-Values

Layered An+1BnO3n+1 (n = 1…∞) Ruddlesden–Popper (RP) phases are a promising system for a variety of applications. Within the RP family, the thermodynamic properties of the phases are essentially additive with variation in the n value, but at present, there are no general approaches that would allow one to evaluate the individual stability of the RP phases and the possibility of their interconversion. The aim of this paper is to present a novel concept for performing a thermodynamic analysis of RP phases using the reciprocal values of the index n. We present an empirical equation ΔG1/n = ΔGP + B1/n + B2/n2, where ΔG1/n and ΔGP are the molar Gibbs energies of formation of the Ruddlesden–Popper (RP) phase (AO)1/nABO3 and the parent ABO3 perovskite, respectively, and n is a stoichiometry index of An+1BnO3n+1 RP phase. The correlation was validated using available thermodynamic data for the systems Sr-Ti-O, Ca-Ti-O, Sr-Zr-O, La-Ni-O, and La-Co-O. For all A-B combinations, the equation quantitatively describes the Gibbs energy of RP phase formation. Predicted values for the non-linear approximation lie within the experimental uncertainty in determining ΔG1/n. The proposed correlation was used to analyze the relative stability of the RP phases and to determine the feasibility of synthesizing new compounds.

New data about the stability of skills for creating clay vessel shapes

The article analyzes the relative stability of skills for creating the shapes of clay vessels, both wheel-made and hand-made ones. Sources of the study included a series of “identical” vessels that were made as part of experiments conducted by employees of the Joint Team for Pottery Study in the 1970s and the Samara Expedition for the experimental study of ancient pottery in 2019–2022. Shape parameters have been identified that exhibit the greatest stability, regardless of the method of making the vessel, the type of building elements and the skill level of a craftsman. These parameters are the inclination angles of the lateral line of the shoulder-brachium frame and the body. The results of the study lead to the conclusion that these parameters can be considered as the most reliable for making conclusions based on the pottery shapes about the degree of cultural and ethnocultural homogeneity of the population groups that left archaeological sites.

The Operando Nature of Isobutene Adsorbed in Zeolite H‐SSZ‐13 Unraveled by Machine Learning Potentials Beyond DFT Accuracy

Unraveling the nature of adsorbed olefins in zeolites is crucial to understand numerous zeolite‐catalyzed processes. A well‐grounded theoretical description critically depends on both an accurate determination of the potential energy surface (PES) and a reliable account of entropic effects at operating conditions. Herein, we propose a transfer learning approach to perform random phase approximation (RPA) quality enhanced sampling molecular dynamics simulations, thereby approaching chemical accuracy on both the determination and exploration of the PES. The proposed methodology is used to investigate isobutene adsorption in H‐SSZ‐13 as prototypical system to estimate the relative stability of physisorbed olefins, carbenium ions and surface alkoxide species (SAS) in Brönsted‐acidic zeolites. We show that the tert‐butyl carbenium ion formation is highly endothermic and no entropic stabilization is observed compared to the physisorbed complex within H‐SSZ‐13. Hence, its predicted concentration and lifetime are negligible, making a direct experimental observation unlikely. Yet, it remains a shallow minimum on the free energy surface over the whole considered temperature range (273‐‐873 K), being therefore a short‐lived reaction intermediate rather than a transition state species.

In-situ FTIR spectroscopy of epoxy resin degradation: kinetics and mechanisms

We report on an in situ FTIR study of the thermo-oxidative degradation of a flexible epoxy resin. Different and complementary approaches to the analysis of the spectral data were employed, providing a detailed description of the process in terms of kinetics and mechanisms. A preliminary normal coordinate analysis, based on the DFT method, allowed for a reliable interpretation of the observed spectrum, increasing the amount of available structural information. Two-dimensional correlation spectroscopy provided details on the evolution of the reacting network structure. The relative stability of the various functional groups was ranked, and the most likely sites of initiation were identified. Oxygen fixation on the network chains produced amide and ketone groups, with the latter developing at a higher rate. The kinetic profiles of various functional groups were accurately simulated by a first-order, biexponential model, which allowed a quantitative comparison among their relative stabilities. The spectroscopic analysis allowed us to propose likely mechanisms and to identify those that occur preferentially.

Exploring the host compound dynamics of 1,4-phenylene-bis(di-p-fluorophenylmethanol) in mixed pyridines

AbstractIn this investigation, the wheel-and-axle host compound, 1,4-phenylene-bis(di-p-fluorophenylmethanol) (H), was demonstrated to have inclusion ability for each of PYR, 2MP, 3MP and 4MP (1:1, 1:2, 1:2 and 1:2 were the H: G ratios). In the equimolar guest competition experiments, H was observed to have an overwhelming affinity for PYR and 4MP relative to 2MP and 3MP. In fact, selectivity coefficients calculated from the non-equimolar binary guest competition experiments suggested that this host compound would be an efficient candidate for the separation of all PYR/2MP mixtures and a 40:60 4MP/3MP solution through host-guest chemistry strategies. SCXRD analyses established the preferred guests (PYR and 4MP) to be involved in significantly shorter stabilizing classical hydrogen bonding interactions with H, explaining the selectivity behaviour of this host compound in the guest mixtures. Additionally, Hirshfeld surface considerations also explained this behaviour, but only for PYR. Furthermore, thermal analyses were used to ascertain the relative thermal stabilities of the four complexes and, satisfyingly, the PYR- and 4MP-containing complexes possessed the greater thermal stabilities compared with H·2(2MP) and H·2(3MP), as was demonstrated by a comparison of their guest release onset temperatures.

Assembly of phyllosphere bacterial community with PsnWRKY70 in poplar

Plant microbiome plays an important role in growth and development, biotic and abiotic stresses, and genotype is one of the key factors in shaping the microbiome. In this study, the effect of PsnWRKY70 on the synthetic bacterial community of poplar was investigated. To explore the assembly mechanism of poplar phyllosphere bacteria. we used 39 strains of bacteria isolated from the phyllosphere of poplar to construct a synthetic bacterial community. The leaves of aseptic poplar tissue culture seedlings were inoculated with synthetic bacterial community, and the bacterial communities of poplar leaves inoculated with synthetic bacterial community for 0 d, 5 d, 10 d and 15d were sequenced for 16 s. Bacterial community composition, PCoA, and Lefse analyses were performed. The results showed that the bacterial community in the phyllosphere of poplar tended to be in a stable equilibrium state after inoculation with the synthetic bacterial community. The results of β diversity analysis showed that there were significant differences in the bacterial community structure of OE, RE and WT leaves at 5d and 10 d after inoculation with Syncom. It is mainly composed of Methylobacteriaceae, Enterbacteriaceae, Agrobacterium, Rhizobium, Pseudoxanthomonas and Stenotrophomonas. The results of differential bacterial analysis showed that Paracoccus, Arthrobacter and Rhodococcus had higher relative abundance and stability in OE line. PsnWRKY70 gene plays an important role in recruiting Paracoccus, Arthrobacter and Rhodococcus strains in poplar leaves.

Community composition and seasonal dynamics of microplastic biota in the Eastern Mediterranean Sea

Marine plastic pollution poses a growing environmental threat, with microplastics accumulating in the global oceans. This study profiles the seasonal dynamics and taxonomic composition of the plastisphere, the microplastic ecosystem, in the Eastern Mediterranean Sea. Using long-read 16 S and 18 S metabarcoding, we analyzed offshore microplastic and whole seawater samples across each season over a two-year period. The analysis revealed a higher richness of prokaryotic communities on microplastics compared to seawater, which was predominantly composed of Proteobacteria and Bacteroidota and exhibited notable seasonal variability. Benthic eukaryotes were enriched on microplastics compared to the surrounding seawater. Diatoms (Bacillariophyceae), in particular, showed significant enrichment within the microplastic eukaryotic community with primarily pennate diatoms of Amphora, Navicula, and Nitzschia genera, whereas the seawater included mostly centric diatoms. Seasonal fluctuations were less pronounced in the microplastic communities than in seawater, highlighting the relative stability of this new human-made ecosystem. These findings underscore the unique ecological niche of microplastic-associated communities in marine environments.