Browse Articles

The mechanics of nucleation and growth and the surface tensions of active matter

Homogeneous nucleation, a textbook transition path for phase transitions, is typically understood on thermodynamic grounds through the prism of classical nucleation theory. However, recent studies have suggested the applicability of classical nucleation theory to systems far from equilibrium. In this article, we formulate a purely mechanical perspective of homogeneous nucleation and growth, elucidating the criteria for the properties of a critical nucleus without appealing to equilibrium notions. Applying this theory to active fluids undergoing motility-induced phase separation, we find that nucleation proceeds in a qualitatively similar fashion to equilibrium systems, with concepts such as the Gibbs–Thomson effect and nucleation barriers remaining valid. We further demonstrate that the recovery of such concepts allows us to extend classical theories of nucleation rates and coarsening dynamics to active systems upon using the mechanically derived definitions of the nucleation barrier and surface tensions. Three distinct surface tensions—the mechanical, capillary, and Ostwald tensions—play a central role in our theory. While these three surface tensions are identical in equilibrium, our work highlights the distinctive role of each tension in the stability of active interfaces and the nucleation and growth of motility-induced phases.

Radiomics-based machine-learning method to predict extrahepatic metastasis in hepatocellular carcinoma after hepatectomy: a multicenter study

HPLC-MS profiling and protective potential of the defatted aqueous methanol extract of two Syzygium species against cadmium chloride-induced nephrotoxicity in rats

Cadmium (Cd), a highly toxic heavy metal, is used in food and agricultural products while displaying nephrotoxicity to animals and humans. The genus Syzygium (Myrtle family) is rich in precious phenolic metabolites with various therapeutic values. This study investigated the phenolic content and the therapeutic potential of the defatted 80% aqueous methanol extract (DE) of S. malaccense and S. samarangense leaves against Cd-induced kidney injury in rats for the first time. High-performance liquid chromatography-Mass spectrometry (HPLC-MS), in addition to Folin-Ciocalteu and aluminium chloride colourimetric methods, depicted the phenolic metabolites, total phenolic content, and total flavonoid content, respectively. The nephroprotective effect was investigated using fifty-six female Sprague Dawley rats divided into eight groups: control group, CdCl2-treated group (3 mg/kg/i.p/7 days), and three groups of each species treated with the DE (250, 500, and 1000 mg/kg/o.p., respectively). The phytochemical analysis revealed the richness of S. samarangense DE by phenolic and flavonoid content over S. malaccense. The HPLC-MS showed the tentative identification of sixty-two compounds, in positive and negative ionization modes, belonging to phenolic acids (1−6), flavonoids (7−52), and miscellaneous compounds (53−62). Both extracts were considered safe up to 5 g/kg. At the maximum tested dose (100 mg/Kg), the DEs significantly (p < 0.001) boosted the levels of antioxidant markers by 3.3–6 fold, lessened the inflammatory indicators by 66.8%−75.1%, and reduced the apoptotic parameters by 45.4–73.3%, compared to the CdCl2-treated group. Additionally, the DEs maintained the mitochondrial function and inhibited autophagy via decreasing adenosine monophosphate-activated protein kinase by 49.2%−50.6%, and baclin-1 by 49.5%−56.1%. Additionally, the DEs increased the mammalian target of rapamycin (mTOR) by 4.7–4.9 fold. Additionally, the DE ameliorated CdCl2-induced elevations in serum ALT and AST, indicating a protective effect against systemic toxicity. Ultimately, the DE of S. malaccense and S. samarangense protect against Cd-induced nephrotoxicity that may be correlated to their abundant phenolic content. However, selecting suitable formulations and implementing clinical studies are among the future directions.

Daily briefing: These rappelling robots autonomously explore underground tunnels

Robust estimation of rotational diffusion tensors of proteins from molecular dynamics simulations

Rotational diffusion is a fundamental physical process that determines the rotational motion of proteins in solution. It plays a role, for example, in molecular association processes and in theories of spectroscopic experiments in solution. In addition to experimental methods, molecular dynamics (MD) simulations have emerged as a powerful method to investigate rotational diffusion. Diffusion models are fitted to rotational correlation functions extracted from the simulations. In this work, we conducted a time-dependent analysis of the model parameters prior to fitting, using extended all-atom MD simulations of ubiquitin as a model system. A comparison to Brownian dynamics (BD) simulations confirms whether the rotational dynamics observed in MD actually follow the theory of Brownian rigid-body diffusion. In addition, the analysis reveals correlation time intervals that are suitable for fitting anisotropic, semi-isotropic, or isotropic diffusion models. To this end, a two-step optimization scheme is employed that combines a global and a local search in parameter space. BD simulations are used to estimate uncertainties of the diffusion coefficients and directional uncertainties of the principal axes. We found that ubiquitin exhibits nearly semi-isotropic rotational dynamics, in good agreement with the experimental NMR data. The approach is general and can be used to investigate, for example, the rotational diffusion of molecules in various biomolecular environments or to compute NMR relaxation parameters of proteins. An implementation of the method is freely available at https://github.com/MolSimGroup/rotationaldiffusion.

Exposure to online hate speech is positively associated with post-traumatic stress disorder symptom severity

Kummerowia striata extract protects paracetamol-induced liver injury by modulating the S1P/Nrf2/Keap1 pathway

Background Drug-induced liver injury remains a significant challenge in both drug development and clinical applications. Acetaminophen (APAP), a commonly used analgesic and antipyretic, can cause liver damage when overdosed, with APAP-induced liver injury being one of the leading causes of acute liver injury. Kummerowia striata (Ks), a leguminous plant, has been reported to contain chemical compounds with anti-inflammatory and antioxidant activities. However, its potential therapeutic effects in liver diseases remain inadequately explored. Objective This study aims to investigate the protective effect of Kummerowia striata extract against APAP-induced acute liver injury and further explore its potential molecular mechanisms. Methods C57BL/6J mice were pre-treated with Ks extract by gavage for 3 days. On the second day, treatment was discontinued, and the mice were fasted for 16 hours. After the fasting period, the final dose of Ks extract was administered, followed by an intraperitoneal injection of APAP (300 mg/kg) 1 hour later to establish a drug-induced liver injury model. Tissue samples were collected 24 hours after modeling. To investigate the molecular mechanisms by which Ks extract prevents APAP-induced acute liver injury, network pharmacology, the GEO database, and molecular docking analysis were employed. Results Ks extract exhibited a significant gender-independent protective effect in preventing APAP-induced acute liver injury in mice. In male mice, Ks extract attenuated the occurrence of acute liver injury by modulating the sphingosine-1-phosphate/ Sphingosine-1-Phosphate Receptor 2/ Sphingosine-1-Phosphate Receptor 4(S1P/S1PR2/S1PR4) signaling pathway and the upstream regulator SPHK1. This, in turn, regulated the binding of Kelch Like ECH Associated Protein 1 (Keap1) to Nuclear factor erythroid 2-related factor 2(Nrf2), alleviating oxidative stress and inflammatory responses. Discussion This study illustrates that Ks exerts a protective effect against APAP-induced acute liver injury by modulating oxidative stress and inflammatory responses through multiple mechanisms. Notably, Ks inhibited Keap1 expression and restored Nrf2 signaling, indicating a potential regulatory role in mitigating mitochondrial oxidative damage and ferroptosis. Furthermore, Ks downregulated SPHK1 expression and reduced levels of the bioactive sphingolipid S1P, as well as its receptors S1PR2 and S1PR4, unveiling a previously unreported involvement of the SPHK1/S1P/S1PR2/4 axis in liver injury. Interestingly, sex-based differences in APAP hepatotoxicity were observed, with female mice exhibiting lower susceptibility, yet still responding to Ks treatment. These findings not only validate the hepatoprotective potential of Ks but also provide new mechanistic insights involving the Nrf2/Keap1 and S1P/S1PR2/S1PR4 signaling pathways, thereby laying a foundation for its development as a candidate therapeutic agent for acute liver injury.

Optimization of microwave absorption properties based on the construction of Ni–TiN heterojunctions

In this study, Ni–TiN@CN nanocapsules were successfully prepared by the DC arc method and the self-polymerization reaction of dopamine. The effect of material composition on their microwave absorbing properties was systematically investigated. The crystal structure, core–shell morphology, and the successful construction of the nitrogen-doped carbon layer of samples were confirmed by x-ray diffractometer, Raman spectroscopy, x-ray photoelectron spectroscopy, transmission electron microscopy, and scanning electron microscopy. The synergistic effect of the dielectric and magnetic losses is optimized by the introduction of Ni elements. Electromagnetic parameter tests show that the dielectric relaxation loss of the material is further significantly enhanced by the multi-interface heterostructure constructed after coating the nitrogen-doped carbon shell layer. Ni–TiN@CN nanocapsules have a reflection loss of −47.74 dB at a thickness of 2.6 mm and a combined effective absorption bandwidth (RL < −20 dB) of 4.5 GHz. It exhibits excellent microwave absorption performance. This study provides a new idea for the design of highly efficient microwave absorbing materials. It confirms that the construction of multi-interface heterostructures can effectively regulate the microwave absorbing properties of materials.

Synthesis and characterization of hematite nanomaterials imprinted with acetone, ethanol and methanol for AI-Based IoT gas sensor arrays

Weight loss journeys: Exploring social influences and determinants of health in an exploratory rural German intervention

Overweight and obesity are highly prevalent across Western populations and contribute substantially to the global burden of non-communicable diseases such as cardiovascular disease and diabetes. Despite numerous intervention efforts, achieving and sustaining long-term weight loss remains a challenge. Social Determinants of Health (SDoH) play a critical role in shaping health outcomes – including weight and weight loss trajectories – and vary across social groups and geographic contexts. This qualitative study explores participants’ perceptions of personal and contextual SDoH influencing their weight loss journeys within a rural German population enrolled in a general practitioner-led pilot intervention. Semi-structured interviews were conducted with 16 participants from the HAPpEN trial (General Practitioner-led Obesity Prevention Program: Exercise and Nutrition), which focused on individuals living in a rural area of Upper Franconia. Interview data were analyzed using a grounded theory-informed approach to qualitative content analysis, guided by the SDoH framework as a sensitizing concept. Coding and theme development followed an iterative process involving constant comparison and discussion within the research team. Key determinants affecting weight loss efforts included individual routines and schedules, social and household networks, mental health, and work-related demands. Broader contextual factors such as socialization, cultural norms, and the availability of health-supporting infrastructure also emerged. The dynamic interplay between personal motivation and structural or environmental influences appeared to be central to weight management success. This study is limited by its small and relatively homogeneous sample – predominantly female and drawn from a single rural region – which may restrict transferability to more diverse populations or urban settings. Nonetheless, the findings offer practical implications for tailoring weight loss interventions to rural contexts by incorporating the complexity of individual and social determinants.

Forces between charge regulated surfaces inside an electrolyte solution

We study the interaction between two charge-regulated surfaces immersed in a 1:1 electrolyte solution, analyzing how this interaction varies with the ionic strength and pH of the solution. This system can be thought to represent two like-charged colloidal particles with radii much larger than the Debye length. Our theoretical approach is based on a recently developed theory that modifies the traditional Poisson–Boltzmann equation to account for the discrete nature of surface groups. We demonstrate that charge regulation has a significant impact on the interaction forces between the surfaces compared to systems with fixed surface charges. Notably, unlike unregulated surfaces, increasing the salt concentration can lead to a stronger repulsive force between the surfaces.

Global map of characterized dust sources using multisource remote sensing data

Abstract The most recent high-resolution global map of dust emission sources is provided by Ginoux et al. (2012), which utilizes an aerosol loading approach based on time series of MODIS Aerosol Optical Depth (AOD). However, advancements in remote sensing technology and analytical techniques have created a growing need for more accurate and up-to-date maps of global dust sources to enhance the understanding and management of this phenomenon. In this study, we first calculated the global mean Sentinel-5P Absorbing Aerosol Index (AAI) for the period 2018–2024. Regions with AAI values greater than 0.25 were identified as potential dust sources through histogram analysis validated by ground truth data. Next, areas without dust emission potential were excluded from the mean AAI map using a multi-stage masking process that considers land surface characteristics such as soil depth, permanent water bodies, and built-up areas. Validation results demonstrate strong performance, with a Precision of 84.7%, Recall of 80.7%, and F1-score of 82.6%, confirming the reliability of the global dust source map produced. The findings indicate that about 5% of the world’s land area acts as a dust emission source, mainly located in North Africa (67%) and Asia (30%). Land use/land cover analysis reveals that global dust sources comprise deserts, vegetative, and hydrological categories, accounting for 65%, 26%, and 9%, respectively. Among these, sandy areas, rangelands, and intermittent water bodies exhibit the largest extent on a global scale, respectively. Natural and human factors contribute 65% and 35%, respectively, to the formation of global dust sources. The frequency of dust events from desert sources has experienced an increasing trend worldwide, but in the case of non-desert sources, it has decreased in some regions, such as the Middle East. This study focused on identifying major dust emission sources based on relatively high aerosol loads over time. Our results provide a new global dust atlas that can serve as a practical foundation for climate modeling and for formulating disaster risk reduction and management plans.

Retraction: Food security management in developing countries: Influence of economic factors on their food availability and access

Investigation of simvastatin and fluvastatin permeation across cell membrane models using molecular dynamics simulations

The chief motivation for the failure of drugs in clinical trials is their low bioavailability caused by the inability to cross the cell membrane. Understanding drug–membrane interactions is crucial for improving therapeutic efficacy. In this work, molecular dynamics simulations were employed to investigate the permeation of simvastatin and fluvastatin across three lipid bilayer models representing normal and cancer cell membranes. Free energy profiles reveal that simvastatin, due to its higher lipophilicity, interacts more strongly with lipid environments, preferentially permeating cancer-like symmetric membranes. Fluvastatin, in contrast, shows less selective behavior across different membrane types, consistent with its charged nature. Statin insertion perturbs membrane structure, increasing area per lipid and decreasing bilayer thickness and lipid order. These findings highlight how membrane composition and asymmetry govern passive drug diffusion and suggest that selective membrane interactions may reflect the differential anticancer potential of statins. The results provide mechanistic insights into structure–permeability relationships and support the strategic use of realistic membrane models in drug discovery and repurposing efforts.

An investigation into enhancing sand stability and minimizing dust emissions through bacterial treatment in arid regions

Comparison between wharton’s jelly and collagen natural hydrogels for human ovarian follicle transplantation as an artificial ovary

Artificial ovary (AO) is a bioengineered approach aimed at increasing fertility potential in certain cases, especially in women and prepubertal girls with a history of cancer. Some natural and synthetic materials can be used for ovary bioengineering. In the current study, we compared two natural hydrogel composites containing alginate (Alg): Wharton’s Jelly (WJ/Alg) and Collagen (Col/Alg) as models for human AO. In total, six experimental groups were designed: WJ/Alg, Col/Alg, WJ/Alg +FSH , Col/Alg +FSH , WJ/Alg +EPO , and Col/Alg +EPO (n = 60). In each group, 40 isolated human ovarian follicles were seeded in 10 µl of the desired hydrogel and xenotransplanted into the right side of the peritoneum in ovariectomized NMRI mice for 1 week. FSH (7.5 IU) and Erythropoietin (EPO; 200 IU/kg as an angiogenic factor) were injected every other day. Histological and immunohistochemical assessments for Vimentin, CD45, and Ki67; Gene expression analysis for GDF9 , Vegf, and CD45 ; and hormonal assays for estradiol and progesterone were performed. Histological staining showed that WJ/Alg can support follicle growth. In contrast, most of follicles in Col/Alg remained at the primordial stage. Although FSH injection helped granulosa cells differentiation, especially in the WJ/Alg group (507.6 ± 134.1 vs 1444 ± 493.6), and EPO injection increased blood vessels in both groups ( p -value<0.0001), the follicles could not preserve in the experimental groups. In addition, there were no significant differences in gene expression and hormonal assays across all groups. Based on the histological analysis, the WJ/Alg-base artificial ovary provided better support for follicle development after 1 week compared to the other groups. In addition, Adjusting FSH and EPO dosage may improve follicle survival and growth in future studies.

Impact of diamino and imidazole functionalization on the photophysical properties and electronic and structural dynamics of the pyrimidine nucleobase

The photostability of DNA and RNA bases to ultraviolet radiation is essential to life, as evidenced by their ability to dissipate excess electronic energy via ultrafast internal conversion. Understanding how the functionalization of pyrimidine and purine affects electronic and structural relaxation pathways is crucial for insights into their selection as life's building blocks. It is also relevant for developing fluorescent biomarkers and photosensitizers for therapeutic applications. This study investigates how the functionalization of the C5=C6 bond in pyrimidine with heavier amino groups instead of hydrogen atoms to form 4,5-diaminopyrimidine, or with an imidazole ring to form purine, affects the photophysical properties and electronic and structural relaxation pathways observed in pyrimidine. The excited-state dynamics of 4,5-diaminopyrimidine, pyrimidine, and purine are disclosed using steady-state and time-resolved spectroscopy, supported by quantum chemical calculations. It is shown that the lowest-energy absorption band of 4,5-diaminopyrimidine is significantly red-shifted compared to that of purine and pyrimidine in both aqueous solution and acetonitrile, while the fluorescence quantum yield also increases. In acetonitrile, the initial 1ππ* state population in 4,5-diaminopyrimidine decays radiatively and nonradiatively to the ground state and can also intersystem cross to populate a long-lived triplet state. In contrast, intersystem crossing is suppressed in aqueous solution, leading to relaxation of the 1ππ* state population through fluorescence emission and internal conversion to the ground state. Our results demonstrated that both the strategic functionalization of pyrimidine and the solvent properties play important roles in tuning the optical properties and the electronic and structural relaxation pathways of the pyrimidine derivatives.

Glaucoma screening in Kazakhstan

Exploring the association between smartphone-based place visitation data and neighborhood-level coronary heart disease in the United States

Coronary Heart Disease (CHD) is the leading cause of death in the United States, affecting over 20.5 million adults. Previous studies link health behaviors – such as dietary behavior, physical activity, smoking, and alcohol consumption – to CHD risk. These studies typically use surveys and interviews, which, despite their benefits, are resource-intensive and limited by small sample sizes. Using large-scale national level anonymized smartphone-based location data, our study examines whether health behaviors that are proxy measured by place visitation are associated with CHD prevalence across US census tracts. This study utilized data from multiple sources, including demographic and socioeconomic characteristics, health outcomes, and smartphone-based place visitation data. Health behavior measures were derived from aggregated smartphone location data at the census tract level, focusing on categories such as food retails, drinking places, and physical activity locations. Three sets of regression analyses were conducted: one using only demographic variables, the second including socioeconomic variables, and another incorporating the derived health behavior measures. Linear and spatial regression analyses were employed to assess the relationship between neighborhood-level CHD prevalence and these behaviors. Findings indicate a significant association between health behaviors that are proxy measured by place visitation data and the prevalence of CHD at the neighborhood level. The models incorporating these behaviors demonstrated improved fitness and highlighted specific behavioral factors such as increased visits to physical activity facilities and healthy food retail associated with lower CHD rates. Conversely, higher visits to less healthy food retail were associated with increased CHD rates. Smartphone-based visitation data offers a novel method to assess health behaviors at a large scale, providing valuable insights for targeting CHD interventions more effectively at the neighborhood level. This approach could enhance our understanding and management of CHD, informing public health strategies and interventions to mitigate this major health challenge.

Spin blockades to hot multi-exciton relaxation in nanocrystals: Case of CdTe

In a recent three pulse “spectator exciton” experiment on quantum confined CdSe nanocrystals, spin orientation conflicts between hot and cold electrons in the same doubly excited nanocrystal were shown to block the former from relaxing to the band edge. This blockage was ultimately overcome by phonon-assisted flipping of the hot carrier’s spin, allowing it to pair with its band edge counterpart within tens of picoseconds. To test the generality of this novel phenomenon, the same approach is used here on nanodots of another II–VI semiconductor, CdTe. Despite difficulties arising from slower electron cooling rates and faster bi-exciton recombination times relative to CdSe, the results demonstrate similar spin blockades to hot bi-exciton cooling in CdTe nanocrystals. This study confirms the general occurrence of spin blockade phenomena in II–VI quantum dots, underscoring the potential of this mechanism for assisting hot electron harvesting. It similarly highlights the inherent limitations of using band edge bleaching signals as ensemble exciton counters when multi-excitons are involved.