Modification Of Interaction Research Articles

The Role of Lysine-Specific Demethylase 1 (LSD1) in Shaping the Endothelial Inflammatory Response.

Inflammation is the body's natural response to stress in the broadest sense. The regulatory mechanisms that control this process, some of which are still unclear, are needed to balance the immune response, but also when insufficient, can cause immunodeficiency resulting in infection, cancer, neurodegeneration or other serious disorders. In this study, we focused on defining the role of lysine-specific demethylase 1 (LSD1), an enzyme involved in modulating the methylation state of lysine, including histone and non-histone proteins, in shaping the inflammatory profile of endothelial cells. To determine the role of LSD1 in the inflammatory response of ECs, cells were stimulated with lipopolysaccharide (100 ng/ml LPS) in the presence and absence of an LSD1 inhibitor (2-PCPA). A transcription model of LSD1 deficient cells (HMEC-1 LSD1 KD) obtained by lentiviral shRNA transduction was also used. The indicated cellular models were analyzed by gene profiling, monitoring of p65 shuttling by Western blotting and immunofluorescence staining. Also chromatin immunoprecipitation (ChIP) was performed to identify the interactions between selected: IL-6/p65 and LSD1. Analysis of both experimental models revealed an altered inflammatory response following both LSD1 inhibition and LSD1 silencing. We observed decreased U-937 monocytes recruitment to LPS-activated endothelial cells and decreased extracellular secretion of many proinflammatory cytokines, also confirmed at the transcript level by RT-qPCR. Monitoring of the LPS-induced p65 translocation revealed inhibition of the NF-kB subunit in LSD1 KD vs nonT as well as due to pretreatment of 2-PCPA cells. Gene profiling performed with RNA microarrays confirmed the obtained biochemical data at the transcript level. In conclusion, the conducted studies showed a proinflammatory profile of LSD1 activity in endothelial cells, revealed by the inhibition of the enzyme activity and confirmed at the transcriptional level by the inhibition of its expression. Although we found significant changes in the modification of interactions between monocytes and endothelial cells as well as in cytokine/chemokine release and expression that were consistent with the altered NF-κB-p65 translocation into the nucleus, we did not identify a direct interaction between LSD1 and the transcription factor. Our finding may have important implications for prevention of cardiovascular diseases at their first stage - activation of the endothelium as well as for tumor cell biology, providing evidence for the use of LSD1 inhibitors to reduce the inflammatory response, which enhances tumor tissue remodeling, angiogenesis and metastasis.

Nucleon clustering at kinetic freezeout of heavy-ion collisions via path-integral Monte Carlo

Clustering of the four-nucleon system at kinetic freezeout conditions is studied using path-integral Monte Carlo techniques. This method seeks to improve upon previous calculations which relied on approximate semiclassical methods or few-body quantum mechanics. Estimates are given for the decay probabilities of the 4N system into various light nuclei decay channels and the strength of spatial correlations is characterized. Additionally, a simple model is presented to describe the impact of this clustering on nucleon multiplicity distributions. The effects of a possible modification of the inter-nucleon interaction due to the close critical line (and hypothetical QCD critical point) on the clustering are also studied.

Vibrational relaxation of monomeric and self-associated acrylonitrile species in solutions

The dynamic interactions between acrylonitrile and carbon tetrachloride in solutions were investigated by means of Raman spectroscopy in a wide concentration range. We progress on the comprehensive understanding of vibrational frequency modulation and dephasing by analyzing the spectra and the time correlation functions of vibrational relaxation. Unlike to the usual Raman line profile analysis, we used an alternative approach to extract valuable parameters related to vibrational short-time dynamics of the system by applying a fitting procedure of the spectra directly in the frequency domain without prejudging the Lorentzian or Gaussian character of the analytical function. We focused on the CN symmetric stretching mode of acrylonitrile, which was used as a probe of the dynamics of these solutions. This relatively complex mode appears as an asymmetric line profile that was decomposed into two individual components assigned to monomeric and self-associated species. Systematic analysis of the dynamic parameters revealed a strong dependence of vibrational relaxation on the local environment around the acrylonitrile species in solutions with carbon tetrachloride. The vibrational relaxation time τV and the frequency modulation time τω increase from dilute to dense solutions implying modification of interactions upon dilution. The variations observed in the second moments of vibrations imply an interplay between repulsive and attractive forces acting on monomeric and self-associated species in solution environment. The relative contribution of the homogeneous and inhomogeneous broadening to the isotropic Raman line profile of the CN symmetric stretching mode of acrylonitrile has been analyzed and discussed in view of the recent phenomenological status of the field.

Interactional modifications between ESL learners in the specification of negotiation of meaning and negative feedback

This project is designed to analyze the interactional modifications in English conversation between two adult Hong Kong ESL learners with varied language proficiency levels. A consensus task relating to the cultural topics was assigned, and the participants were required to come up with an agreement within a limited time. The host has taken an observant role in the interaction and rarely interferes with the discussion. The speech data is recorded and transcribed. It is hypothesized that (1) the subjects could attain the intended communicative goal and (2) the subject with relatively higher language proficiency would take an initiative role during the negotiation of meanings. The analysis session focuses on investigating three main types of interactional modifications: clarification requests, recasts, and explicit correction while the emergence and the effectiveness of different types of interactional modifications are also evaluated. It is observed that implicit feedback like clarification requests and recast appear more frequently compared with explicit feedback in adult communication. Nonetheless, a recast might sometimes be omitted if the recipients tend to focus on the content instead of the form of English or when a long recast is involved. Hence, it is reflected that a short and precise recast should be adopted to give effective feedback in the communication.

Three-body optical potentials in (d,p) reactions and their influence on indirect study of stellar nucleosynthesis

Model uncertainties arising due to suppression of target excitations in the description of deuteron scattering and resulting in a modification of the two-body interactions in a three-body system are investigated for several $(d,p)$ reactions serving as indirect tools for studying the astrophysical $(p,\ensuremath{\gamma})$ reactions relevant to $rp$ process. The three-body nature of the deuteron-target potential is treated within the adiabatic distorted-wave approximation (ADWA) which relies on a dominant contribution from the components of the three-body deuteron-target wave function with small $n\text{\ensuremath{-}}p$ separations. This results in a simple prescription for treating the explicit energy dependence of two-body optical potentials in a three-body system requiring nucleon optical potentials to be evaluated at a shifted energy with respect to the standard value of half the deuteron incident energy. In addition, the ADWA allows for leading-order multiple-scattering effects to be estimated, which leads to a simple renormalization of the adiabatic potential's imaginary part by a factor of two. These effects are assessed using both nonlocal and local optical potential systematics for $^{26}\mathrm{Al}$, $^{30}\mathrm{P}$, $^{34}\mathrm{Cl}$, and $^{56}\mathrm{Ni}$ targets at a deuteron incident energy of 12 MeV, which is typical for experiments with radioactive beams in inverse kinematics. The model uncertainties induced by the three-body nature of deuteron-target scattering are found to be within $40%$ both in the main peak of angular distributions and in total $(d,p)$ cross sections. At higher deuteron energies, around 60 MeV, model uncertainties can reach 100% in the total cross sections. A few examples of application to astrophysically interesting proton resonances in $^{27}\mathrm{Si}$ and $^{57}\mathrm{Cu}$ obtained using $(d,p)$ reactions and mirror symmetry are given.

Phototribology: Control of Friction by Light.

In dry sliding, the coefficient of friction depends on the material pair and contact conditions. If the material and operating conditions remain unchanged, the coefficient of friction is constant. Obviously, we can tune friction by surface treatments, but it is a nonreversible process. Here, we report active control of friction forces on TiO2 thin films under UV light. It is reversible and stable and can be tuned/controlled with the light wavelength. The analysis of atomic force microscopy signals by wavelet spectrograms reveals different mechanisms acting in the darkness and under UV. Ab initio simulations on UV light-exposed TiO2 show a lower atomic orbital overlapping on the surface, which leads to a friction reduction of up to 60%. We suggest that photocontrol of friction is due to the modification of atomic orbital interactions from both surfaces at the sliding interface.

The Ecological Importance of Allelopathy

Allelopathy (i.e., chemical interaction among species) was originally conceived as inclusive of positive and negative effects of plants on other plants, and we adopt this view. Most studies of allelopathy have been phenomenological, but we focus on studies that have explored the ecological significance of this interaction. The literature suggests that studies of allelopathy have been particularly important for three foci in ecology: species distribution, conditionality of interactions, and maintenance of species diversity. There is evidence that allelopathy influences local distributions of plant species around the world. Allelopathic conditionality appears to arise through coevolution, and this is a mechanism for plant invasions. Finally, allelopathy promotes species coexistence via intransitive competition, modifications of direct interactions, and (co)evolution. Recent advances additionally suggest that coexistence might be favored through biochemical recognition. The preponderance of phenomenological studies notwithstanding, allelopathy has broad ecological consequences.

Can Work Interactions Cause Technostress during the COVID-19 Crisis?A Dyadic Study

The Corona Virus Disease 2019 (COVID-19) containment protocols led to two broader shifts in the workplace namely the increased use of information and communication technologies (ICTs); and modified work interactions. The aim of the current study is to investigate how work relationships impact the technostress or the stress experienced by using ICTs during the pandemic. We measured work interactions through (i) interactional justice or fairness of interpersonal treatments received at work; and (ii) relational crafting or proactive modifications in the frequency and nature of work interactions. Through mixed-methods design, our research seeks to answer how manager-employee interactions are impacted during the COVID-19 crisis and how these interactions determine the level of technostress experienced by each party. For Study 1, we conducted Actor Partner Interdependence Model (APIM) analysis on manager-employee dyads to elucidate how they have modified their work interactions during the pandemic. Our findings indicate a strong interdependence between managerial interactional justice and employee relational crafting and vice-versa. Engagement in relational crafting also significantly informed the technostress for both managers and employees. In Study 2, semi-structured interviews were conducted for completeness and complementarity of the first study. Through thematic analysis, we gained in-depth insights into the modifications of work interactions during the COVID-19. The proposed relationships contribute to refining our understanding of justice, job design, and stress literature during times of emergency. Managerial implications during and beyond the COVID-19 times are discussed.

Morphological, magnetic and EPR studies of ZnO nanostructures doped and co-doped with Ni and Sr

Herein, were analyzed the effects of Sr and Ni addition on the morphological, electronic and magnetic properties of ZnO nanoparticles synthesized by the sol gel route. Morphological analysis showed agglomerated particles with nonuniform shapes (polyhedral, hexagonal and spherical) and the average size distributions were calculated counting more than 100 nanoparticles (sizes between 43 and 75 nm). For pure ZnO sample, the selected area electron diffraction (SAED) showed bright and concentric discontinuous diffraction rings, while the co-doped samples, presented patterns well-organized concentric circular rings, typical of reflection of regularly arranged atoms. The electron paramagnetic resonance (EPR) was employed to analyze the intrinsic defects due to the dopant inclusion. In addition, the EPR spectra were simulated using the spin quantum number (S = 1) for Ni2+ to understand the experimental results. Ni ions were used as a local probe in the comparative study by EPR, capturing subtle modifications in the zero-field interactions due to induced strain in the lattice. Microscopically the changes observed, through the EPR study, result from the reduction of the axial distortion of the ligand field and increasing in the distortion perpendicular to the principal axis. Magnetic study showed a typical significant diamagnetism at 300 K, while a paramagnetic contribution was more evident at 4 K. The work contributes to clarify the complex magnetic response in ZnO nanoparticles doped and co-doped with Sr and Ni.

Annual course of temperature and precipitation as proximal predictors of birds’ responses to climatic changes on the species and community level

Abstract The study was conducted in the landscapes of south-eastern Ukraine during the nesting seasons 1988–2018. Within the landscape system associated with the Molochny Estuary, the ten most important ecosystem types were investigated, including the following: agricultural land, vegetated strips, meadows, islands and spits, reedbeds, urban areas, salt marshes, steppe, cliffs, artificial forests. Bird species responded to temperature and precipitation gradients. The patterns of responses were presented using Huisman, Olff and Fresco expanded by the Jansen-Oksanen hierarchical models. The nature of species response in the gradient of temperature or precipitation conditions depends on the type of particular ecosystem and is not uniform for all populations inhabiting the different landscape types. The bird communities were revealed to demonstrate an abrupt dynamic over time. The continuous changes in community structure initiated by the external environmental factors are combined with modifications of internal biotic interactions, which may lead to abrupt reorganization of the community.

The dynamics of N6-methyladenine RNA modification in interactions between rice and plant viruses

BackgroundN6-methyladenosine (m6A) is the most common RNA modification in eukaryotes and has been implicated as a novel epigenetic marker that is involved in various biological processes. The pattern and functional dissection of m6A in the regulation of several major human viral diseases have already been reported. However, the patterns and functions of m6A distribution in plant disease bursting remain largely unknown.ResultsWe analyse the high-quality m6A methylomes in rice plants infected with two devastating viruses. We find that the m6A methylation is mainly associated with genes that are not actively expressed in virus-infected rice plants. We also detect different m6A peak distributions on the same gene, which may contribute to different antiviral modes between rice stripe virus or rice black-stripe dwarf virus infection. Interestingly, we observe increased levels of m6A methylation in rice plant response to virus infection. Several antiviral pathway-related genes, such as RNA silencing-, resistance-, and fundamental antiviral phytohormone metabolic-related genes, are also m6A methylated. The level of m6A methylation is tightly associated with its relative expression levels.ConclusionsWe revealed the dynamics of m6A modification during the interaction between rice and viruses, which may act as a main regulatory strategy in gene expression. Our investigations highlight the significance of m6A modifications in interactions between plant and viruses, especially in regulating the expression of genes involved in key pathways.

Leveraging Physiologically Based Pharmacokinetic Modeling and Experimental Data to Guide Dosing Modification of CYP3A-Mediated Drug-Drug Interactions in the Pediatric Population.

Solithromycin is a novel fluoroketolide antibiotic that is both a substrate and time-dependent inhibitor of CYP3A. Solithromycin has demonstrated efficacy in adults with community-acquired bacterial pneumonia and has also been investigated in pediatric patients. The objective of this study was to develop a framework for leveraging physiologically based pharmacokinetic (PBPK) modeling to predict CYP3A-mediated drug-drug interaction (DDI) potential in the pediatric population using solithromycin as a case study. To account for age, we performed in vitro metabolism and time-dependent inhibition studies for solithromycin for CYP3A4, CYP3A5, and CYP3A7. The PBPK model included CYP3A4 and CYP3A5 metabolism and time-dependent inhibition, glomerular filtration, P-glycoprotein transport, and enterohepatic recirculation. The average fold error of simulated and observed plasma concentrations of solithromycin in both adults (1966 plasma samples) and pediatric patients from 4 days to 17.9 years (684 plasma samples) were within 0.5- to 2.0-fold. The geometric mean ratios for the simulated area under the concentration versus time curve (AUC) extrapolated to infinity were within 0.75- to 1.25-fold of observed values in healthy adults receiving solithromycin with midazolam or ketoconazole. DDI potential was simulated in pediatric patients (1 month to 17 years of age) and adults. Solithromycin increased the simulated midazolam AUC 4- to 6-fold, and ketoconazole increased the simulated solithromycin AUC 1- to 2-fold in virtual subjects ranging from 1 month to 65 years of age. This study presents a systematic approach for incorporating CYP3A in vitro data into adult and pediatric PBPK models to predict pediatric CYP3A-mediated DDI potential. SIGNIFICANCE STATEMENT: Using solithromycin, this study presents a framework for investigating and incorporating CYP3A4, CYP3A5, and CYP3A7 in vitro data into adult and pediatric physiologically based pharmacokinetic models to predict CYP3A-mediated DDI potential in adult and pediatric subjects during drug development. In this study, minor age-related differences in inhibitor concentration resulted in differences in the magnitude of the DDI. Therefore, age-related differences in DDI potential for substrates metabolized primarily by CYP3A4 can be minimized by closely matching adult and pediatric inhibitor concentrations.

Modification of short-range repulsive interactions in ReaxFF reactive force field for Fe–Ni–Al alloy* *Project supported by the National Magnetic Confinement Fusion Energy Research Project (Grant Nos. 2019YFE03120003, 2018YFE0307100, and 2017YFE0302500) and the National Natural Science Foundation of China (Grant Nos. 11975034, 11921006, 12004010, and U20B2025).

The short-range repulsive interactions of any force field must be modified to be applicable for high energy atomic collisions because of extremely far from equilibrium state when used in molecular dynamics (MD) simulations. In this work, the short-range repulsive interaction of a reactive force field (ReaxFF), describing Fe–Ni–Al alloy system, is well modified by adding a tabulated function form based on Ziegler–Biersack–Littmark (ZBL) potential. The modified interaction covers three ranges, including short range, smooth range, and primordial range. The short range is totally predominated by ZBL potential. The primordial range means the interactions in this range is the as-is ReaxFF with no changes. The smooth range links the short-range ZBL and primordial-range ReaxFF potentials with a taper function. Both energies and forces are guaranteed to be continuous, and qualified to the consistent requirement in LAMMPS. This modified force field is applicable for simulations of energetic particle bombardments and reproducing point defects' booming and recombination effectively.

Modification of rectal function and emotion by repetitive transcranial magnetic stimulation in humans

Gut microbiota may affect function of the dorsolateral prefrontal cortex (DLPFC). However, there have been a few studies on modification of brain-gut interactions with repetitive transcranial magnetic stimulation (rTMS) to the DLPFC. We hypothesized that stimulation of the right or left DPFC by rTMS modifies the brain-gut interactions in humans. Subjects were 25 healthy males. Viscerosensory evoked potential (VEP) with sham (0 mA) or actual (30 mA) electrical stimulation (ES) of the rectum was taken after sham, low frequency rTMS at 0.1 Hz, and high frequency rTMS at 10 Hz to the right or left DLPFC. Rectal tone was measured with a rectal barostat. Visceral perception and emotion were analyzed using ordinates scale, rectal barostat, and viscerosensory evoked potential. Low frequency rTMS to the right DLPFC significantly reduced the visceral sensation and emotion composite score evoked by ES at 30 mA (p < 0.05). Plasma ACTH was significantly increased by high frequency rTMS to the right or left DLPFC (p < 0.05). Rectal fine contractions were significantly induced by low frequency rTMS to the right or left DLPFC and high frequency rTMS to the right DLPFC (p < 0.05). These results suggest that stimulation of the right or left DPFC by rTMS modifies the brain-gut interactions in humans.

STZ-diabetic rat heart maintains developed tension amplitude by increasing sarcomere length and crossbridge density.

New Findings What is the central question of this study? In the papillary muscle from type I diabetic rats, does diabetes‐associated altered ventricular function result from changes of acto‐myosin interactions and are these modifications attributable to a possible sarcomere rearrangement? What is the main finding and its importance? For the first time, we showed that type‐I diabetes altered sarcomeric ultrastructure, as seen by transmission electron microscopy, consistent with physiological parameters. The diabetic condition induced slower timing parameters, which is compatible with a diastolic dysfunction. At the sarcomeric level, augmented β‐myosin heavy chain content and increased sarcomere length and crossbridges' number preserve myocardial stroke and could concur to maintain the ejection fraction. We investigated whether diabetes‐associated altered ventricular function, in a type I diabetes animal model, results from a modification of acto‐myosin interactions, through the in vitro recording of left papillary muscle mechanical parameters and examination of sarcomere morphology by transmission electron microscopy (TEM). Experiments were performed on streptozotocin‐induced diabetic and age‐matched control female Wistar rats. Mechanical isometric and isotonic indexes and timing parameters were determined. Using Huxley's equations, we calculated mechanics, kinetics and energetics of myosin crossbridges. Sarcomere length and A‐band length were measured on TEM images. Type I and III collagen and β‐myosin heavy chain (MHC) expression were determined by immunoblotting. No variation in resting and developed tension or maximum extent of shortening was evident between groups, but diabetic rats showed lower maximum shortening velocity and prolonged timing parameters. Compared to controls, diabetics also displayed a higher number of crossbridges with lower unitary force. Moreover, no change in type I and III collagen was associated to diabetes, but pathological rats showed a two‐fold enhancement of β‐MHC content and longer sarcomeres and A‐band, detected by ultrastructural morphometry. Overall, these data address whether a preserved systolic function accompanied by an altered diastolic phase results from a recruitment of super‐relaxed myosin heads or the phosphorylation of the regulatory light chain site in myosin. Although the early signs of diabetic cardiomyopathy were well expressed, the striking finding of our study was that, in diabetics, sarcomere modification may be a possible compensatory mechanism that preserves systolic function.

Molecular dynamics shows complex interplay and long-range effects of post-translational modifications in yeast protein interactions.

Post-translational modifications (PTMs) play a vital, yet often overlooked role in the living cells through modulation of protein properties, such as localization and affinity towards their interactors, thereby enabling quick adaptation to changing environmental conditions. We have previously benchmarked a computational framework for the prediction of PTMs' effects on the stability of protein-protein interactions, which has molecular dynamics simulations followed by free energy calculations at its core. In the present work, we apply this framework to publicly available data on Saccharomyces cerevisiae protein structures and PTM sites, identified in both normal and stress conditions. We predict proteome-wide effects of acetylations and phosphorylations on protein-protein interactions and find that acetylations more frequently have locally stabilizing roles in protein interactions, while the opposite is true for phosphorylations. However, the overall impact of PTMs on protein-protein interactions is more complex than a simple sum of local changes caused by the introduction of PTMs and adds to our understanding of PTM cross-talk. We further use the obtained data to calculate the conformational changes brought about by PTMs. Finally, conservation of the analyzed PTM residues in orthologues shows that some predictions for yeast proteins will be mirrored to other organisms, including human. This work, therefore, contributes to our overall understanding of the modulation of the cellular protein interaction networks in yeast and beyond.

Getting to the Root of Belowground High Temperature Responses in Plants.

The environment is continuously challenging plants. As a response, plants use various coping strategies, such as adaptation of their growth. Thermomorphogenesis is a specific growth adaptation that promotes organ growth in response to moderately high temperature. This would eventually enable plants to cool down by dissipating the heat. Although well understood for shoot organs, the thermomorphogenesis response in roots only recently obtained increasing research attention. Accordingly, in the last few years, the hormonal responses and underlying molecular players important for root thermomorphogenesis were revealed. Other responses triggered by high temperature in the root encompass modifications of overall root architecture and interactions with the soil environment, with consequences on the whole plant. Here, we review the scientific knowledge and highlight the current understanding on roots responding to moderately high and extreme temperature.

The Effect of Salinity and Nutrient Load on the Ecosystems of Selected Lakes in the South of Siberia

Salinity largely determines the species diversity and structure of the food web in lake ecosystems. Many studies have been focused on the salinity tolerance of various plankton species. There are fewer studies investigating the modifications in the food web interactions under the effect of salinity. An appropriate system for such studies is closely located lakes of different salinity. We took samples during the summer stratification and analyzed the physicochemical and biological characteristics of 20 lakes (salinity 0.1-35 g/l) in southern Siberia in order to provide general description of this system and to test a number of hypotheses about the effect of salinity on the structure of the food web. The analysis revealed two key factors structuring ecosystems of the studied lakes. The species composition of zooplankton was determined by salinity, with a decrease in the number of species and the transformation of the community from a diverse community of zooplankton (salinity up to 3 g/l) to the dominance of large daphnia (3-8 g/l), copepods (&gt; 8 g/l), small cladocerans and rotifers (20-30 g/l), and Artemia (&gt; 30 g/l). The top predator (fish) was eliminated at salinity above 10 g/l. The biomass of zooplankton did not depend on salinity, but significantly increased in lakes with an increased nutrient load. The nutrient load also had a significant effect on the concentration of total phosphorus, turbidity and transparency of water, and the concentration of chlorophyll “a”. Thus, we recorded the structuring effect of the nutrient load (bottom-up control) on the biomass of the trophic levels and the parameters of water transparency, while salinity transformed the trophic chain from the top, leading to the disappearance of fish and a change in the dominant species of zooplankton. At the same time, salinity did not affect the biomass of the trophic levels. In order to detect top-down effects in the ecosystems of saline lakes, it is necessary to perform a comparative analysis of the seasonal dynamics of ecosystems of lakes with different salinity

Modifications in the nanoparticle-protein interactions for tuning the protein adsorption and controlling the stability of complexes

We report the pathways to suppress or enhance the protein adsorption on nanoparticles and thereby control the stability of the nanoparticle-protein complexes with the help of selective additives. This has been achieved by tuning the electrostatic interaction between the nanoparticles and proteins, in the presence of surfactant and multivalent counterions. The preferential binding of the proteins with the surfactant and multivalent ions induced charge reversibility of nanoparticles can lead to adsorption of an otherwise non-adsorbing protein and vice versa. The findings are demonstrated for anionic silica nanoparticles and two globular proteins [lysozyme (cationic) and bovine serum albumin (BSA) (anionic)] as model systems, in the presence of two ionic surfactants [anionic sodium dodecyl sulfate (SDS) and cationic dodecyltrimethylammonium bromide (DTAB)], and ZrCl4 as multivalent salt. Small-angle neutron scattering with the unique advantage of contrast variation has been used to probe the role of individual components in the multi-component system. It is shown that the non-adsorbing behavior of BSA with silica nanoparticles changes into adsorbing in the presence of oppositely charged DTAB surfactant, whereas the strong adsorbing behavior of lysozyme on nanoparticles modifies to be non-adsorbing in the presence of oppositely charged SDS surfactant. The presence of multivalent counterions (ZrCl4) leads the charge reversal of the nanoparticles, transforming the lysozyme from adsorbing to non-adsorbing, and no significant change in the behavior of BSA. The results presented can find potential applications in the field of nanobiotechnology.

Ferromagnetism in two-dimensional Fe3GeTe2 ; Tunability by hydrostatic pressure

We studied the effect of hydrostatic pressure on the magnetic properties of the highly anisotropic van der Waals ferromagnetic metal ${\mathrm{Fe}}_{3}\mathrm{Ge}{\mathrm{Te}}_{2}$ (FGT) with the field applied along the easy axis. The paramagnetic-to-ferromagnetic transition occurs at the Curie temperature ${T}_{c}=180\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ at ambient pressure, and ${T}_{c}$ decreases monotonically by up to 15 K as the pressure increases up to 1.44 GPa, while the magnetization is suppressed by the pressure. By using high-pressure x-ray diffraction techniques, we found that the Fe-Fe bond lengths tend to decrease, and the Fe-Ge(Te)-Fe bond angles deviate away from ${90}^{\ensuremath{\circ}}$ under hydrostatic pressures, indicating the modification of the exchange interactions. First-principles calculations further confirm the pressure effects. These results suggest that the competition between direct-, super-, and double-exchange interactions plays a crucial role in the pronounced magnetic response under the hydrostatic pressure, i.e., the direct-exchange becomes stronger at a higher pressure and, hence, leading to increased antiferromagnetic components and thus deceased ${T}_{c}$. The highly tunable magnetic properties under hydrostatic pressure in this system provide robust routes for spin manipulation in low-dimensional material systems.