Browse Articles

Probing the effect of PEG-DNA interactions and buffer viscosity on tethered DNA in shear flow

DNA flow-stretching is a widely employed, powerful technique for investigating the mechanisms of DNA-binding proteins involved in compacting and organizing chromosomal DNA. We combine single-molecule DNA flow-stretching experiments with Brownian dynamics simulations to study the effect of the crowding agent polyethylene glycol (PEG) in these experiments. PEG interacts with DNA by an excluded volume effect, resulting in compaction of single, free DNA molecules in PEG solutions. In addition, PEG increases the viscosity of the buffer solution. By stretching surface-tethered bacteriophage lambda DNA in a flow cell and tracking the positions of a quantum dot labeled at the free DNA end using total internal reflection fluorescence (TIRF) microscopy, we find that higher PEG concentrations result in increased end-to-end length of flow-stretched DNA and decreased fluctuations of the free DNA end. To better understand our experimental results, we perform Brownian dynamics simulations of a bead-spring chain model of flow-stretched DNA in a viscous buffer that models the excluded volume effect of PEG by an effective attractive interaction between DNA segments. We find quantitative agreement between our model and the experimental results for suitable PEG-DNA interaction parameters.

Mixed wave mode: Direct evidence of phase transition during uphill-diffusion-based regular pattern formation

The formation of uphill-diffusion-based regular patterns in thin films of solutions was reported two years ago, which was explained as phase transition under non-equilibrium conditions in spinodal decomposition systems. However, definitive evidence is still required to confirm further that the regular patterns are produced via phase transition indeed rather than anisotropic spinodal decomposition. In this work, we observed that an ordered harmonic chemical wave and random spinodal wave can be simultaneously formed in polymer semiconductor solution. Such a mixed wave mode offers clear evidence that the ordered patterns originated from phase transition at non-equilibrium conditions.

CFD simulation of air layer effects on RT42 PCM melting in a square cell

Abstract Latent heat storage technology has been receiving significant attention from scientists, researchers, and engineers working in solar heating and cooling, waste heat recovery, as well as building energy management. Phase change materials (PCMs) have been extensively utilized for this purpose due to their high energy storage capacity and cost-effectiveness. In this study, a numerical investigation was conducted to evaluate heat transfer in paraffin wax RT42 during its complete phase transition from solid to liquid within a square cell, both with and without an air layer on the left hot wall, with the rest of the walls thermally insulated. The enthalpy-porosity approach was quantitatively analysed using the ANSYS/FLUENT 16 program. The results indicate that the presence of a 1 mm thick air layer doubled the complete melting time, and a 2 mm thick air layer tripled the melting time compared to scenarios without an air layer. Additionally, it was shown that thermal conduction drives early melting, while density differences influence free convection in later stages. This study underscores the significant impact of air layers in delaying the melting process of PCMs paraffin wax in square latent heat storage units. Furthermore, guidelines for future investigation were provided, including examining the effects of adding air layers and providing a heat flow from the top or bottom of the square cell. This further research might assist in revealing more specifics of the interactions among the environment, phase change mechanisms, and heat transport in thermal energy storage systems.

Financing sustainability: Applying the BIOFIN framework to government investments in conserving native and indigenous livestock breeds in central India

Biodiversity conservation is a key responsibility for signatories of the Convention on Biodiversity. India is legally committed to the Aichi Biodiversity Targets (ABTs) and the United Nations’ sustainable development goals (SDGs), with a focus on protecting its livestock diversity and genetic resources. Livestock diversity is crucial for maintaining ecosystem functionality and supporting the livelihoods of indigenous communities by contributing to the rural economy. However, urbanization, rapid land use changes, agricultural mechanization, loss of pastoral lands, and emerging diseases have significantly reduced indigenous livestock diversity. The growing demand for high-yield livestock breeds further threatens native and indigenous varieties. This study examines the financial mechanisms employed by the public sector Animal Husbandry Department in Madhya Pradesh, India, using the Biodiversity Finance Initiative (BIOFIN) framework. It assesses the availability of funding across five BIOFIN categories—conservation, sustainable use, education and awareness, policy, and access and benefit sharing—to meet state biodiversity targets aligned with the Aichi Targets. A total of 43 schemes were identified and mapped to these categories. From 2016 to 2022, approximately INR 5,159.88 crore (~US $727.4 million) was invested in livestock conservation and sustainable production in the state. The BIOFIN methodology has facilitated robust financial planning for the livestock sector. The sector is meeting the financial needs assessed in the Madhya Pradesh Biodiversity Strategy and Action Plan, 2018−30, through systematic investments for the conservation and sustainability of livestock biodiversity with an effective awareness extension program. While progress has been made, the emphasis on increasing native livestock production continues to pose challenges to biodiversity conservation.

Observation of three types of NDR in flexible VOx Mott memristors

In this study, the negative differential resistance (NDR) phenomenon in a flexible VOx Mott memristor has been investigated. Our findings indicate that these memristors can exhibit three NDR phenomena depending on the compliance current conditions. Specifically, under low compliance current, the memristors are forming-free and display a continuous “S-type” NDR1 characteristic. When subjected to high compliance currents, electrical forming occurs, leading to a Mott phase transition and the subsequent emergence of both S-type NDR2 and “snap-back” NDR. Furthermore, while forming-free devices produce stable NDR1, they are unable to generate stable oscillation pulses due to the lack of a fixed low resistance. In contrast, devices that have undergone the forming process can generate stable oscillating pulses with good threshold switching stability exceeding 107 times.

Side‐On Coordination in Molecular Alkaline Earth Metal Hypofluorites FM(η ² ‐OF) (M = Mg, Ca, Sr, and Ba)

Abstract Side‐on coordinated molecular hypofluorites FM(η 2 ‐OF) (M = Mg, Ca, Sr, and Ba) were prepared by co‐deposition of laser‐ablated alkaline earth metal atoms with diluted OF 2 in cryogenic matrices. The structures parallel the non‐VESPR structures of alkaline earth metal difluorides and dihydrides, such that FMg(η 2 ‐OF) is planar, FCa(η 2 ‐OF) is planar but with a shallow bending‐potential curve, while FSr(η 2 ‐OF) and FBa(η 2 ‐OF) are non‐planar. Bonding analyses show that the interactions between the metal center M 2+ and the negatively charged ligands F − and OF − are mainly electrostatic. Moreover, for FMg(η 2 ‐OF), donation of electron density from OF − to empty s and p orbitals of magnesium is involved. However, for the heavier alkaline earth metal compounds, the donation to empty d orbitals of the metal center becomes dominant in orbital interactions, which contributes to their non‐planar structures.

Non-destructive testing of steel-lined concrete structure using multiple agents with deep prior

Diagnostic accuracy of circulating tumor DNA for detection of ALK rearrangement in lung cancer: A systematic review and meta-analysis of 14 studies

Background Circulating tumor DNA (ctDNA) is evolving into a promising non-invasive approach for the detection of ALK rearrangement. This meta-analysis was designed to determine the diagnostic value of ctDNA for ALK rearrangement in lung cancer patients. Methods We performed a comprehensive publication search in Pubmed, Cochrane library, and Web of Science to identify the potentially relevant studies. Eligible studies were pooled to calculate the overall sensitivity, specificity, and diagnostic odds ratio (DOR). The area under the receiver operating-characteristic curve (AUC) was used to evaluate the overall diagnostic performance. Results Thirteen eligible articles involving fourteen studies were identified in our meta-analysis, with a total of 1,138 participants. The pooled sensitivity, specificity, DOR, and AUC of ctDNA for ALK status detection were 0.61 (95% CI: 0.49, 0.72), 1.00 (95% CI: 0.98, 1.00), 188.19 (95% CI: 30.79, 1150.05) and 0.92, respectively. No publication bias was found among these studies (P = 0.42). Conclusion Detecting ALK rearrangement in ctDNA demonstrates adequate diagnostic accuracy and could serve as a highly specific test in lung cancer patients.

Opto-acoustic resonance-enabled ultra-low phase noise microwave generation via coupled optoelectronic oscillators

Ultra-low phase noise microwave sources constitute critical components for advanced information and communication systems. This study presents a coupled optoelectronic oscillator (COEO) based on forward stimulated Brillouin scattering (FSBS) opto-acoustic resonance, achieving sub-Hertz linewidth and ultra-low phase noise microwave generation through coordinated opto-electro-acoustic multiphysics control. The design implements an FSBS fiber resonator that leverages group velocity matching between optical fields and transverse acoustic modes, generating narrowband gain via distributed opto-acoustic coupling, thereby significantly reducing reliance on high-Q filters. Optoelectronic feedback injection of FSBS signals into the fiber cavity enables locking of opto-acoustic oscillation mode, effectively suppressing side-mode competition and thermally induced phase noise. Experimental results demonstrate the output microwave signal linewidth of this COEO is 0.1 Hz, the phase noise at 10 kHz frequency deviation is lower than −130 dBc/Hz, maintaining merely 200 Hz frequency drift over 120-min operation. This work provides an ideal signal source combining ultra-low noise and high stability for next-generation wireless communications and precision radar systems while establishing pathways for nonlinear opto-acoustic coupling in complex media.

Obesity drives temporally distinct physical activity disruptions in mice under a fixed 24-h light-dark cycle

Plant recruitment six years after the Samarco’s tailings-dam disaster: Impacts on species richness and plant growth

One of the greatest tragedies in Brazilian mining history occurred in November 2015 in Mariana, Minas Gerais state, when a dam from the mining company Samarco was breached. Millions of mine tailings from this upstream embankment were dumped over the Doce River basin, impacting an area of approximately 1469 ha of riparian vegetation. Our objective was to experimentally investigate whether plant recruitment and establishment are impaired in areas affected by tailings six years after the deposition. To achieve this goal, in 2021 we compared soil chemical properties between affected and unaffected areas, performed a soil seed bank experiment in controlled conditions, and conducted a greenhouse growth experiment using the two most abundant plant species. Affected soils presented lower fertility and organic matter content. At the same time, the mean abundance and richness of emerging plants did not differ between soils. Still, affected areas exhibited approximately 35% lower accumulated species richness (gamma diversity) than unaffected ones. The three most abundant species in both areas represented 34% of the individuals, being Marsypianthes chamaedrys (Vahl) Kuntze, Ludwigia octovalvis (Jacq.) P.H. Raven and Ageratum conyzoides L. In the growth experiment, plants growing in affected soils presented reduced height and stem diameter increment (L. octovalvis) or allocated fewer resources to root production than aerial parts (M. chamaedrys), potentially in response to soil infertility and density. Even after six years, our results showed that tailings-affected areas continue to experience negative impacts on plant recruitment, highlighting its adverse effects on ecosystem functions and services.

Defects-driven abnormal thermal expansion behavior

Low thermal expansion alloys are typically developed by incorporating negative thermal expansion materials into metal matrices. However, the mismatches of lattice structure and opposite thermal expansion behavior between constituent phases frequently induce defects that interact with lattice vibrations, thereby complicating the expected thermal response. Here, we demonstrate that the mismatch induced defects can fundamentally overturn conventional predictions based on phase mixing rules. By incorporating LaFe9.8Co1.1Al2.1 particles into a magnesium matrix, we observe an anomalous thermal expansion behavior: low particle concentrations lead to an increase in the coefficient of thermal expansion, while higher concentrations result in a significant reduction in it. This inversion is driven by dislocation generation and immobilization at particle–matrix interfaces, as revealed by multiscale microstructural analyses. Our findings demonstrate that thermal volumetric behavior in composites can be actively tuned through defect engineering, providing a viable strategy for designing dimensionally stable structural materials under thermal loading.

Larissa K. S. von Krbek

Light‐Driven Ratchet Mechanism Accelerates Regioselective Metal‐Cation Exchange in a Heterobimetallic Helicate

Abstract Molecular machines rely on their capacity to exploit non‐equilibrium processes to perform work. However, the development of these non‐equilibrium processes, such as molecular ratchets, is still in its early stages. Here, we report a diazocine‐containing ligand ( L ) harbouring two distinct chelating coordination sites that can self‐sort into dinuclear homo‐ and heterobimetallic helicates ([Fe II 2 L ](OTf) 4 , [Co II 2 L ](OTf) 4 , [Zn II 2 L ](OTf) 4 , [Zn II Fe II L ](OTf) 4 , [Zn II Co II L ](OTf) 4 ) with precisely controlled metal cation distribution. The photoisomerisation of the helicates operates via a molecular ratchet mechanism, resulting in metastable diastereomers that shift the system from thermodynamic equilibrium. Continuous white‐light irradiation autonomously drives this ratchet process, selectively enriching an out‐of‐equilibrium pseudo‐mesocate structure. Crucially, the ratchet mechanism can significantly accelerate metal‐cation exchange from the [Zn II 2 L ](OTf) 4 helicate to the [Zn II Fe II L ](OTf) 4 helicate. Thus, the system operates in a manner reminiscent of a “claw machine”, selectively seizing Fe II ions when subjected to a precisely controllable external stimulus. These findings lay the foundation for creating adaptive and reconfigurable supramolecular structures that use non‐equilibrium phenomena on a molecular level.

A survey of critically endangered Plecturocebus oenanthe in Moyobamba’s urban forests, Peru

The effect of tennis on male bone mineral density: A meta-analysis

Background As an asymmetrical sport, tennis positively influences the increase of bone mineral density (BMD) in adolescents. However, most current studies focus on specific body regions, there is a lack of systematic analysis of the impact of tennis on BMD in various parts of the body. Therefore, this study aims to systematically assess the impact of tennis on BMD in different areas of the body. Objective This study aimed to systematically evaluate the effects of tennis on BMD in males. Methods Comprehensive search was conducted across databases including Web of Science, PubMed, CNKI, and Embase to identify high-quality randomized controlled trials examining the effects of tennis on BMD. The search covered literature from database inception to March 2025. Data were screened, extracted, coded, and statistically analyzed using Review Manager 5.3. Study selection was based on the PICOS criteria: (i) male tennis players compared to non-tennis players of the same age; (ii) tennis intervention group versus groups engaging in other regular physical activities; (iii) outcome indicators included bone mineral content (BMC) and BMD; and (iv) study design included cross-sectional studies, cohort studies, or controlled experiments. Result A total of 10 articles involving 761 male participants aged between 10 and 26 were included in the analysis. Tennis intervention was found to significantly improve bone measures in several areas. Specifically, it led to increases in dominant arm BMC (SMD = 0.57 mg/mm, 95% CI [0.01, 1.13], P = 0.04), lumbar spine BMD (MD = 0.10 g/cm 2 , 95% CI [0.08, 0.11], P < 0.00001), dominant arm and radius BMD (SMD = 1.34 g/cm 2 , 95% CI [0.49, 2.80], P = 0.002), and right femur BMD (MD = 0.10 g/cm 2 , 95% CI [0.02, 0.18], P = 0.02). These differences were statistically significant (P < 0.05). Conversely, tennis had no significant effect on whole-body BMC (MD = 25.51 mg/mm, 95% CI [-38.43, 85.35], P = 0.43), non-dominant arm BMC (SMD = 0.03 mg/mm, 95% CI [-0.31, 0.37], P = 0.88), total body BMD (MD = 0.00 g/cm 2 , 95% CI [-0.01, 0.01], P = 0.97), femoral neck BMD (MD = 0.01 g/cm 2 , 95% CI [-0.00, 0.01], P = 0.30), or left femur BMD (MD = -0.01 g/cm 2 , 95% CI [-0.07, 0.05], P = 0.84). These findings were not statistically significant (P > 0.05). Additionally, subgroup analyses further revealed that tennis training exerted a targeted impact on BMD. Training durations of more than 7 years and at least 15 hours per week significantly improved BMD in the dominant arm and radius. Additionally, significant improvements in the non-dominant arm and radius BMD were observed in participants with over 2 years of training experience. Enhancement of greater trochanter BMD was closely associated with age of training initiation, with significant improvements noted when training began after age 15. In contrast, tennis had minimal influence on femoral neck BMD. Conclusion Tennis effectively enhances BMD in the dominant arm, radius, lumbar spine, greater trochanter, and right lower limb. The effects are asymmetrical, favoring the dominant side. Therefore, to maintain balanced development of BMC and BMD in both limbs, it is recommended to include contralateral (non-dominant side) training during tennis practice. Systematic review registration https://www.crd.york.ac.uk/PROSPERO/identifier : CRD42023486547. Registration date: March 10, 2025.

Fabrication and structure analysis of freestanding superconducting YBa2Cu3O7−x membranes

YBa2Cu3O7−x (YBCO) superconducting freestanding membranes are expected to further expand the application scenarios of flexible electronic devices if the key problem of exfoliating the water-sensitive YBCO films from rigid substrates without damage can be solved. In this work, the two prominent features of Sr4Al2O7 (SAOT), ultrafast water solubility and the ability to sustain epitaxial strain, were utilized to reduce the etching of YBCO and improve the film quality. With SAOT as the buffer layer, YBCO flexible membranes measuring 100 mm2 were achieved from epitaxial films on LAO, STO, and LSAT substrates. Characterizations using synchrotron radiation 3D diffraction, soft x-ray absorption spectroscopy, and electrical transport properties verify that the rapid exfoliation prevents elemental and structural changes and preserves the superconductivity of the YBCO membranes. Transmission electron microscopy studies on the resulting YBCO or YBCO-composite membranes reveal microstructural details such as local crystallinity, phase distribution, domain boundaries, and artificial pinning centers. The work sheds light on the fabrication and investigation of flexible water-sensitive materials.

Solid‐State NMR Reveals Reorganization of the <i>Aspergillus fumigatus</i> Cell Wall Due to a Host‐Defence Peptide

Abstract The limited availability of antifungal drug treatments and the rising issue of drug resistance highlight the urgent need for new antifungal drugs to combat drug‐resistant Aspergillus fumigatus . The host‐defence peptide cathelicidin‐2 has demonstrated a significant inhibitory effect on azole‐resistant Aspergillus fumigatus but its mechanism of action remains elusive. We applied a tailored set 1 H and 13 C detected solid state nuclear magnetic resonance experiments to elucidate the cell wall composition of Aspergillus fumigatus and to shed light on the mechanism of action of the peptide within the cell wall. Our results revealed that presence of the peptide affects galactosaminogalactan, an important component involved in the pathogenesis of invasive aspergillosis, as well as other specific polysaccharides and amino acids within the mobile cell wall domain. At longer exposure times, the peptide also influences the rigid cell wall domains by enhancing water penetration into the hydrophobic rigid cell wall domain. The findings reveal how the peptide can reach the plasma membrane and may aid the design of novel antifungal drugs with enhanced efficacy.

Design of a class E inverter with stabilized output power using artificial neural network for applications in biomedical implants

A case study of transferring the effect of demographic factors on e-waste recycling to the waste container assignment model

Collecting waste directly from the consumer could be considered the initial stage of electronic waste recycling. Despite numerous studies employing mathematical assignment models to determine the optimal location of containers for waste collection from end-users, no research has been deemed to incorporate the demographic characteristics of the regions into these assignment models. This study aims to accomplish more effective results by incorporating the factors affecting consumers’ recycling trends (the population, income level, education level, and age distribution of the relevant region) into the assignment model. By integrating abovementioned parameters characterizing regional differences in the micro sense and country-based differences in the macro sense into the assignment model, a generic model is structured to help local administrators determine their first-step e-waste recycling policies. The main contribution of the proposed model is that significantly more realistic results regarding the amount of e-waste to be collected can be obtained when factors indicating regional differences are included in the container assignment model. Thus, local governments could utilize these findings as a reference to create more sustainable policies for the next steps of e-waste recycling. The model application is demonstrated through a case study for a local government in Turkey.