Browse Articles

Erratum: “Inference of Onsager coefficient from microscopic simulations by machine learning” [J. Chem. Phys. 162, 034901 (2025)]

Genome-wide association and selection studies for pod dehiscence resistance in the USDA soybean germplasm collection

As a domestication trait, pod dehiscence has a pleiotropic effect on agronomic traits and significantly contributes to yield loss in soybean. Population studies are still required to comprehend the genetic basis of dehiscence and to develop pod dehiscence-resistant cultivars with the optimal haplotype, thereby improving soybean production. We collected data for one wild (Glycine soja) (G. soja) and four cultivated (Glycine max) (G. max) populations from the USDA database. The G. max populations were evaluated in multi-environment conditions and used for genome-wide association study (GWAS) and selection. GWAS captured 86 quantitative trait loci (QTLs). Seventy-four new QTLs were colocalized in two different G. max populations, and 12 QTLs were closely mapped with previously reported QTLs. Eight out of 86 QTLs were associated with the domestication of pod dehiscence. We implemented marker-assisted selection (MAS) and genomic selection (GS) approaches to select pod dehiscence-resistant accessions with the best haplotype and lowest genomic breeding value (GBV), respectively. While our findings could be utilized for biology, genetics, and plant breeding, selecting pod dehiscence-resistant cultivars with the optimal haplotype will need further studies to confirm additional QTLs and assess advanced GS models.

Comment on “Third density and acoustic virial coefficients of helium isotopologues from <i>ab initio</i> calculations” [J. Chem. Phys. 160, 244305 (2024)]

The impact of brominated flame retardants exposure on serum total bilirubin: A cross-sectional analysis

Background Brominated flame retardants (BFRs) are harmful, bioaccumulative, and persistent environmental pollutants, posing significant health risks. Elevated bilirubin levels can cause neurotoxicity and damage to the heart, liver, kidneys, and other organs. This study utilizes National Health and Nutrition Examination Survey (NHANES) data to investigate the association between exposure to BFRs and total bilirubin (TB) levels in adult participants. Methods Based on data from the NHANES 2007-2016, TB levels were divided into tertiles. Spearman’s rank correlation was used to analyze the relationship between individual BFRs and TB levels. Weighted linear regression analysis, restricted cubic splines (RCS), and stratified analysis were conducted to assess the correlation between individual BFRs and TB levels. Weighted quantile sum (WQS) regression and quantile-based g-computation (QGC) analysis were used to comprehensively evaluate the impact of BFRs exposure on serum TB levels. Results The study included 5831 participants. The results showed that PBB153, PBDE17, PBDE47, PBDE85, PBDE99, PBDE100, PBDE209, and PBDE183 were significantly correlated with TB levels (p &lt;  0.05), with PBDE183 having the highest Spearman rank correlation coefficient of 0.292. After adjusting for confounding factors, most BFR remained significantly positively correlated with TB, while PBDE153 (β: - 0.031, 95%CI: - 0.317, 0.255, p =  0.829) and PBDE66 (β: 0.285, 95%CI: - 0.208, 0.777, p =  0.253) were not statistically significant. RCS analysis indicated that PBDE153 concentration had a significant U-shaped correlation with TB (p &lt;  0.05), while PBDE17, PBDE99, PBDE154, and PBDE209 had an inverted “J”-shaped correlation (p &lt;  0.05). PBB153, PBDE66, PBDE85, and PBDE183 also exhibited significant nonlinear S-shaped correlations with TB (p &lt;  0.05). After stratification by age and gender, most individual BFR remained significantly positively correlated with TB levels (p &lt;  0.05). WQS regression and QGC analysis indicated that mixed BFRs exposure was positively correlated with TB levels (β: 0.553, 95%CI: 0.384, 0.722, p &lt;  0.001 and β: 1.060, 95%CI: 0.587, 1.532, p &lt;  0.001), with PBDE183 contributing the most. Conclusions BFRs exposure is significantly positively correlated with TB levels, further suggesting the potential health impact of BFRs exposure on humans.

Theoretical approach to the crystal structure of poly(butylene 2,5-furandicarboxylate) as revealed by density functional theory

In this work, we present a new model of the crystalline structure of the poly(butylene 2,5-furandicarboxylate) (PBF). This new structure has been derived using an ab initio density functional theory methodology and focusing on the agreement between the experimental and theoretical x-ray diffraction patterns. An extensive study has been performed to analyze the possible conformations that the polymeric strand can adopt in its crystalline form, leading to 60 initial crystalline structures. Due to thermal motion, which cannot be easily tackled with the ab initio methodology, and small inaccuracies, which are intrinsic to this calculation method, the theoretical unit cell dimensions can slightly differ from those obtained in the crystallization experiments. Thus, a structural refinement method has been employed to overcome these discrepancies and procure a crystalline structure whose x-ray diffraction pattern is consistent with the experimental one. For the proposed crystalline structure of PBF, both the powder diffraction pattern and the fiber diffraction diagram show a remarkable agreement with those available in the literature.

Association between timing of exanthema subitum and febrile seizures: The Japan environment and children’s study

Recently, episodes of exanthema subitum (ES) have been occurring later than expected in Japanese patients, though the effects of this delayed timing remain unclear. Therefore, this study examined the association between ES timing and febrile seizure (FS) in Japanese children. Information on the diagnoses of ES and FS was obtained from the Japan Environment and Children’s Study, a nationwide prospective birth cohort study including 97,410 mothers and their children. Two groups were created: early ES (first ES episode between birth and 11 months of age) and late ES (first ES episode between 12 and 23 months of age) groups. Multivariate logistic regression analyses were performed to compare the cumulative incidence rate of FS between the groups. Moreover, because a single episode of fever implies that the ES and FS occurred simultaneously, we examined the association between the ES timing and the simultaneous co-occurrence of FS with ES in a limited cohort with one fever episode until the age of 24 months. In total, 27,238 full-term children were included, with 12,565 (46.1%) in the early ES group and 14,673 (53.9%) in the late ES group. Late ES was estimated to increase the cumulative incidence risk of FS until the age of 24 months (adjusted odds ratio 1.46; 95% confidence interval [1.32–1.61]) and 48 months (1.26 [1.15–1.37]). The limited cohort included 1,022 children, and late ES was estimated to increase the risk of FS with ES (4.39 [1.48–13.02]). Late ES is estimated to increase the risk of FS. Further basic research and cohort studies, including virological examinations, are required to elucidate the pathogenesis of ES with FS.

Primitive and non-primitive model electrolytes: Comparing ion-related Helmholtz energies using molecular simulations

Two main frameworks are commonly used to describe electrolyte solutions: the non-primitive model, which rigorously accounts for all interactions between ions and solvent molecules; and the primitive model, which treats the solvent as a dielectric continuum, only describing ion–ion interactions explicitly. The primitive model offers simple Helmholtz energy expressions, including the Debye–Hückel (DH) equation, the primitive mean spherical approximation (MSA), and the Born theory of solvation. In this work, we evaluate the accuracy of primitive model approaches by comparing their Helmholtz energies with data from molecular simulations obtained for non-primitive model electrolyte solutions. We model electrolyte solutions as mixtures of equally sized, charged, and (non-polarizable) dipolar Lennard-Jones particles. Using thermodynamic integration, we isolate the Helmholtz energy contributions related to solvent–solvent, ion–solvent, and ion–ion interactions. Molecular simulations are performed across two temperatures and two densities, a range of charges, dipole moments, and ion mole fractions (0.005 ≤ xions ≤ 0.05). Our results show that while the primitive model expressions provide a qualitatively reasonable description of electrolyte solutions, they systematically underestimate the Helmholtz energy contributions associated with ion–solvent and ion–ion interactions. Achieving quantitative agreement requires empirical adjustments to the Born radius. Notably, the optimized Born radii are significantly larger than the actual ion sizes used in the molecular simulations, questioning the primitive model’s applicability. This work presents rigorous benchmarks for the use of MSA, DH, and Born theories, along with molecular simulation data for non-primitive model electrolytes. These benchmarks provide insights for refining existing models and advancing the development of new equations of state for electrolyte solutions.

Exploring Marine natural products as potential Quorum sensing inhibitors by targeting the PqsR in Pseudomonas aeruginosa: Virtual screening assisted structural dynamics study

Antibiotic resistance is a critical global health issue, and Pseudomonas aeruginosa is a particularly challenging pathogen. This gram-negative bacterium is notorious for its high virulence and resistance to antimicrobial agents, making it a leading cause of nosocomial infections, significantly impacting public health. The adaptability and multidrug resistance of P. aeruginosa exacerbate treatment difficulties, resulting in increased morbidity and mortality rates worldwide. Consequently, targeting bacterial quorum sensing (QS) systems is a promising strategy for the development of novel antimicrobial compounds against this resilient pathogen. In this study, a structure-based virtual screening (SBVS) approach was employed to identify marine natural products (MNPs) as potential lead molecules targeting the biofilm-forming PqsR protein of P. aeruginosa. A total of ~37,000 MNPs were initially evaluated and ranked based on docking scores using high-throughput virtual screening (HTVS), Standard Precision (SP), and Extra Precision (XP) methods. Ten lead molecules (five from the CMNPD database and five from the MNPD database) were shortlisted based on their docking scores (&lt;−10.0 kcal/mol) and binding free energy values (MM-GBSA ΔG &lt;−40 kcal/mol). Their drug-likeness profiles were assessed using stringent criteria in the QikProp module of Schrödinger, and their chemical reactivity was evaluated through density functional theory (DFT) calculations. The structural and energetic interactions between the identified MNPs and the PqsR-binding pocket were validated through molecular dynamics simulations (MDS) and binding free energy (BFE) calculations. Structural dynamic analyses revealed that the MNP-bound PqsR complexes demonstrated stable interactions within the binding pocket, with hydrophobic residues such as L208, I236, and I263 playing a crucial role in maintaining stability. Among the identified MNPs, CMNPD14329, CMNPD23880, MNPD13399, and MNPD13725 emerged as promising lead molecules for further research. These candidates can serve as foundations for developing structural analogs with enhanced binding affinities for PqsR and other biofilm-forming proteins. Further experimental validation is essential to confirm the therapeutic potential of these identified MNPs.

The dynamics of substituted benzoate anions undergoing counterion condensation in lamellar phase dispersions

We have studied the interaction of three ortho-substituted benzoate anions (2-ethylbenzoate, 2-chlorobenzoate, and 2-hydroxybenzoate) and three para-substituted benzoate anions (4-ethylbenzoate, 4-chlorobenzoate, and 4-hydroxybenzoate) with lamellar phase dispersions of the di-chain cationic surfactants 2,3-diheptadecyl ester ethoxypropyl-1,1,1-trimethyl-ammonium chloride (DHTAC) and dioctadecyl-dimethyl-ammonium chloride (DODMAC) using avoided level crossing muon spin resonance (ALC-μSR) spectroscopy. Highly polarized spin probes were produced in situ by the addition of muonium to the aromatic anions, and the muon and methylene proton hyperfine coupling constants (hfccs) of these radical anions were determined from the Δ1 and Δ0 resonance fields in the ALC-μSR spectra. The motionally averaged dipolar muon hfccs, |Dμ‖|, were determined from the width and amplitude of the Δ1 and Δ0 resonances and used to estimate the extent of reorientational motion. The results are consistent with the counterions being electrostatically trapped near the oil/water interface of the surfactant bilayer and undergoing large amplitude anisotropic motion. This motion is generally more restricted in DODMAC bilayers compared with DHTAC, which is likely related to the relative flexibility of the headgroups to which the counterions are loosely bound. The motion of the ortho isomers is generally more restricted than the para isomers, while there is no obvious trend regarding the ethyl, chloro, and hydroxy substituents.

Listeria monocytogenes infection in intestinal epithelial Caco-2 cells with exposure to progesterone and estradiol-17beta

Listeria monocytogenes (Lm) is a food-borne pathogen associated with serious pregnancy complications, including miscarriage, stillbirth, preterm birth, neonatal sepsis, and meningitis. Although Lm infection within the gastrointestinal tract is well studied, little is known about the influence sex hormones may have on listeriosis. Estradiol-17beta and progesterone not only have receptors within the gastrointestinal tract but are significantly increased during pregnancy. The presence of these hormones may play a role in susceptibility to listeriosis during pregnancy. Caco-2 cell monolayers were grown on trans-well inserts in the presence of estradiol 17-beta (E2), progesterone (P4), both hormones, or no hormones (control). Cells were inoculated with Lm for 1 hour, before rinsing with gentamycin and transfer to fresh media. Trans-epithelial resistance was recorded hourly, and bacterial burden of the apical media, intracellular lysates, and basal media were assessed at 6 hours post inoculation. There were no significant differences in bacterial replication when directly exposed to sex steroids, and Caco-2 cell epithelial barrier function was not impacted during culture with Lm. Addition of progesterone significantly reduced intracellular bacterial burden compared to estradiol 17-beta only and no hormone controls. Interestingly, estradiol 17-beta only treatment was associated with significantly increased Lm within the basal compartment, compared to reduction in the intracellular and apical layers. These data indicate that the sex hormones P4 and E2 alone do not significantly impact intestinal epithelial barrier integrity during listeriosis, but that addition of P4 and E2, alone or in combination, was associated with reduced epithelial cell bacterial burden and apical release of Lm.

Response to “Comment on ‘Third density and acoustic virial coefficients of helium isotopologues from <i>ab initio</i> calculations’” [J. Chem. Phys. 162, 244305 (2025)]

Efficient cutting stock optimization strategies for the steel industry

This study addresses a cutting stock problem in steel cutting industry by developing a mathematical model in which machine specifications and cutting conditions are constraints. The solution process involves three key steps: (i) Problem representation, where feasible cutting solutions are modeled based on pre-cut steel bars and customer orders, (ii) Problem space reduction, which reduces the problem space by eliminating suboptimal solutions and following manufacturer loss limits, and (iii) Optimal solution search, whereas the optimal solution is identified using a new Adaptive Pathfinding Optimization Algorithm. This algorithm combines a newly proposed Wandering Ant Colony Optimization with a brute force method, and uses specific conditions to determine which of these two approaches to be used to obtain the solution. The proposed algorithm can also be applied to other cutting stock problems, such as paper roll cutting, metal rod cutting, and wood plank cutting. The algorithm was applied to real customer orders in a steel manufacturer and showed significant benefits by reducing the number of planners from four to merely one person and decreasing the cutting planning time from six hours to under one hour. Additionally, the algorithm yields an average cost saving of USD 3.95 per ton, or 52.18% of the baseline.

Applying the active learning strategy to the construction of full-dimensional neural network potential energy surfaces: Critical tests in H2O–He spectroscopic calculation

An uncertainty-driven active learning strategy was employed to achieve efficient point sampling for full-dimension potential energy surface constructions. Model uncertainty is defined as the weighted square energy difference between two neural network models, and the local maximums of uncertainty would be added to the training set by two criteria. A two-step sampling procedure was introduced to reduce the computational costs of expansive double-precision neural network training. A reference potential energy surface (PES) of the 6-D H2O–He system was constructed first by the MLRNet model with a weighted Root-Mean-Square-Error (RMSE) of 0.028 cm−1. The full-dimension long-range function was fitted by a pruned basis expansion method. The current sampling method is reliable for the long-range switched fundamental invariant neural network (LS-FI-NN) to construct spectroscopically accurate PES, where the single precision model achieves a test set RMSE of 0.3253 cm−1 with 472 fitting points and the double precision model is 0.0710 cm−1 with only 613 points. In comparison, the MLRNet requires 652 points to reach a similar accuracy. However, the MLRNet, with fewer parameters, shows lower training errors across all sampling cycles and lower test errors in the first few cycles, indicating its potential with an appropriate sampling procedure. The spectroscopic calculations were performed to validate the accuracy of PESs. The energy levels of the double precision LS-FI-NN showed great agreement with the reference PES’s results, with only 0.0161 and 0.0044 cm−1 average errors for vibrational levels and the band origin shifts.

Investigating the influence of language teachers’ constructivist self-efficacy on their practice of constructivism in Ghanaian language and culture instruction

The education system in Ghana is undergoing a transition from a behaviorist instructional philosophy to a constructivist one, aiming to produce learners who can actively contribute to nation-building. Nonetheless, given the heavy demands on teachers regarding this abrupt shift into constructivist teaching, there is a need to examine teachers’ sense of efficacy in relation to the enactment of the core principles of this novel instructional philosophy—i.e., social, cognitive, and critical constructivism— laid down in the newly introduced standards-based curriculum. An explanatory sequential mixed method was used to obtain data from basic school teachers in the Sunyani-West Municipal of Bono Region, Ghana. Using adapted teacher self-efficacy and constructivist learning environment scales, quantitative data were gathered from 104 teachers. Qualitative data were also gathered from 15 conveniently sampled language teachers to augment the quantitative findings. Using partial least squares structural equation modelling, a significant positive association was discovered between teachers’ efficacy and the practice of social and cognitive constructivism. Nonetheless, teachers’ efficacy did not statistically predict their practice of critical constructivism. The qualitative results showed that sociocultural concerns probably accounted for the insignificant association between efficacy and critical constructivism. It was therefore concluded that sociocultural norms designed for bringing up a child in Ghana tend to inhibit the enactment of critical constructivism. The study recommends that the National Council for Curriculum and Assessment, in partnership with the Ghana Tertiary Education Commission, should update teacher professional development programs in universities and colleges of education to incorporate constructivist principles, particularly critical pedagogy, aiming to produce competent teachers capable of fostering learners’ autonomy, critical thinking, and problem-solving skills as outlined in the Standards-Based Curriculum (SBC).

Frontal polymerization in thin layers: Hydrodynamic effects and asymptotic dynamics

Buoyancy-driven convection currents arise from temperature gradients in thermal frontal polymerization (FP) when the spatially localized polymerization reaction travels perpendicularly to the gravity field. We propose a theoretical study of the system dynamics under adiabatic conditions. The polymer and the reactant mixture are considered to be in the same liquid phase, but the viscosity can increase with the degree of polymerization. We find that the reaction zone propagates as a hot spot-like pattern with a broken symmetry in both the vertical and horizontal directions. Furthermore, the system can reach an asymptotic dynamics characterized by a front with a steady shape that propagates at constant speed with a steady vortex surrounding it. As the strength of the vortex is increased, either by decreasing the reactants’ viscosity or by increasing the layer’s thickness, we observe a transition between (i) a passive regime predicted by pure reaction–diffusion and hydrodynamic models and (ii) an active chemo-hydrodynamic regime where such models separately break down. In the active regime (ii), the front speed decreases as convection intensifies. By means of a scaling analysis, we explain how hydrodynamic currents might lower the velocity of a polymerization wave. As the viscosity of the polymer is enlarged, the flow is shifted ahead of the reaction zone and becomes more symmetrical with respect to the middle of the system, as recently observed in solid–liquid FP experiments [Y. Gao et al., Phys. Rev. Lett. 130, 028101 (2023) and Y. Gao et al., Int. J. Heat Mass Transf. 240, 126622 (2025)].

Agro-physiological and transcriptome profiling reveal key genes associated with potato tuberization under different nitrogen regimes in aeroponics

Nitrogen (N) is a crucial nutrient for the growth and development of potatoes. However, excessive use of nitrogen fertilizers can have detrimental effects on human health, aquatic ecosystems, and the environment. Therefore, understanding the genes involved in nitrogen metabolism is essential for developing future strategies to improve nitrogen use efficiency (NUE) in plants. This study aimed to identify genes associated with high tuber yield in two contrasting potato varieties Kufri Jyoti (N inefficient) and Kufri Pukhraj (N efficient) grown under low and high nitrogen regimes using an aeroponics system. Both varieties were grown in aeroponics with two nitrogen doses (low N: 0.5 mM N; high N: 5 mM N) using a completely randomized design (CRD) with three replications over two years. The phenotypic results confirmed that Kufri Pukhraj was more nitrogen use efficient compared to Kufri Jyoti, particularly under low nitrogen conditions. Additionally, transcriptome analysis produced high-quality data ( ≥ Q20), ranging from 4.35 to 5.46 Gb per sample. Statistically significant genes (p ≤  0.05) were identified based on the reference potato genome. Differentially expressed genes (DEGs) were categorized as either up-regulated or down-regulated in leaf and tuber tissues. Transcriptome profiling of both tuber and leaf tissues revealed genes associated with traits contributing to high tuber yield under both high and low nitrogen conditions. The DEGs were further characterized through gene ontology (GO) annotation and KEGG pathway analysis. Selected genes were validated through real-time quantitative polymerase chain reaction (RT-qPCR) analysis. In summary, several genes were identified as being involved in high tuber yield component traits in potatoes under different nitrogen conditions. These included glutaredoxin, transcription factors (BTB/POZ, AP2/ERF, and MYB), nitrate transporter, aquaporin TIP1;3, glutamine synthetase, aminotransferase, GDSL esterase/lipase, sucrose synthase, UDP-glycosyltransferases, osmotin, xyloglucan endotransglucosylase/hydrolase, and laccases. Additionally, we identified overexpressed genes including cysteine protease inhibitor 1, miraculin, sterol desaturase, and pectinesterase in Kufri Pukhraj under low N stress. Our study highlights these genes’ roles in enhancing tuber yield in potatoes cultivated under both high and low nitrogen in aeroponics.

Are nanocubes more efficient than nanospheres to enhance the nuclear magnetic relaxation of water protons? A Monte Carlo simulation study

Iron oxide superparamagnetic nanoparticles have been extensively studied as T2 contrast agents in magnetic resonance imaging. The theory of nuclear magnetic relaxation induced by superparamagnetic nanoparticles has been validated by numerous experimental studies in the case of spherical particles. Recently, several studies focused on the synthesis of cubic nanoparticles. Some of them reported significantly higher relaxivities compared to their spherical counterpart and attributed this increase to their specific shapes. This work investigates the impact of cube-shaped nanoparticles on nuclear magnetic relaxation through Monte Carlo methods. Transverse relaxation at high static magnetic field is simulated by modeling the proton diffusion in the magnetic field generated by a cubic or a spherical nanoparticle. The results indicate that, in the case of magnetite nanoparticles, there is no significant difference between both shapes for sizes above 30 nm when particles are compared at equal volumes and magnetization. Below this size, a −40%–15% variation of the relaxation rates is predicted for the cubic case compared to the spherical case. These results are explained using general relaxation models that incorporate the distribution of the magnetic field generated by the nanoparticles. The simulation predictions are compared to some experimental results from the literature, revealing that, in some cases, the magnetic field specific to the nanoparticle shape alone cannot explain the observed increase in the relaxation rate of cubic nanoparticles.

Association between Body Roundness Index and Depression Among Middle-aged and Older Adults in Chinese Communities: An Empirical Analysis Based on CHARLS Data

Background The relationship between depression and obesity has been confirmed by multiple studies. Compared to conventional measurement indicators such as body mass index or waist circumference, the body roundness index (BRI) demonstrates higher accuracy in assessing body fat content, especially visceral adiposity. Nevertheless, despite the advantages of BRI in measuring fat, the specific link between BRI and depression remains unclear. This study aims to clarify the potential correlation using data from the China Health and Retirement Longitudinal Study (CHARLS). Methods This study used CHARLS data from 2015 and 2020. We screened and included 7,258 middle-aged and older adults without depressive symptoms at baseline. We explored the connection between BRI and depression risk through logistic regression analyses, restricted cubic spline analyses, subgroup analyses, and interaction tests Results After adjusting for covariates, a positive correlation was observed between BRI and depression risk. Specifically, a one-unit increase in BRI led to a 14% increase in depression risk (OR =  1.14, 95% CI: 1.09-1.20, P &lt;  0.001). Conclusion BRI is linked to a higher risk of depression in middle-aged and older adults in China and can be used as a simple indicator to predict depression.

Disentangling signal contributions in two-dimensional electronic spectroscopy in the pump–probe geometry

Since its introduction almost three decades ago, two-dimensional electronic spectroscopy (2DES) has evolved into a mature and powerful technique to reveal the inner workings of quantum systems with high temporal and spectral resolution. In general, this technique can isolate different contributions to the nonlinear response and provides access to different dynamical quantum pathways of the system evolution. Such isolation of pathways can be achieved in different experimental geometries. In its original, fully noncollinear implementation, directional phase matching allows for such signal isolation, while in the modern commonly employed pump–probe geometry, experimentally challenging phase-cycling schemes are employed. Here, we show how rephasing, non-rephasing, and zero- and double-quantum 2DES signals can be isolated in the pump–probe geometry without a need for phase-cycling. For this, we utilize established causality restrictions of the nonlinear response, allowing us to separate the different contributions in the spectral domain. We demonstrate this using data recorded for a molecular J-aggregate, acting as an effective three-level system. This approach bridges the gap between the capabilities of shaper-based and fully noncollinear 2DES and experimentally simpler implementations, such as those based on birefringent common-path interferometers.

Correction: Substance use and disordered eating risk among college students with obsessive-compulsive conditions