SORI: A softness-rendering interface to unravel the nature of softness perception.

Tactile perception of softness serves a critical role in the survival, well-being, and social interaction among various species, including humans. This perception informs activities from food selection in animals to medical palpation for disease detection in humans. Despite its fundamental importance, a comprehensive understanding of how softness is neurologically and cognitively processed remains elusive. Previous research has demonstrated that the somatosensory system leverages both cutaneous and kinesthetic cues for the sensation of softness. Factors such as contact area, depth, and force play a particularly critical role in sensations experienced at the fingertips. Yet, existing haptic technologies designed to explore this phenomenon are limited, as they often couple force and contact area, failing to provide a real-world experience of softness perception. Our research introduces the softness-rendering interface (SORI), a haptic softness display designed to bridge this knowledge gap. Unlike its predecessors, SORI has the unique ability to decouple contact area and force, thereby allowing for a quantitative representation of softness sensations at the fingertips. Furthermore, SORI incorporates individual physical fingertip properties and model-based softness cue estimation and mapping to provide a highly personalized experience. Utilizing this method, SORI quantitatively replicates the sensation of softness on stationary, dynamic, homogeneous, and heterogeneous surfaces. We demonstrate that SORI accurately renders the surfaces of both virtual and daily objects, thereby presenting opportunities across a range of fields, from teleoperation to medical technology. Finally, our proposed method and SORI will expedite psychological and neuroscience research to unlock the nature of softness perception.

Growth mechanisms and anisotropic softness-dependent conductivity of orientation-controllable metal-organic framework nanofilms.

Conductive metal-organic frameworks (cMOFs) manifest great potential in modern electrical devices due to their porous nature and the ability to conduct charges in a regular network. cMOFs applied in electrical devices normally hybridize with other materials, especially a substrate. Therefore, the precise control of the interface between cMOF and a substrate is particularly crucial. However, the unexplored interface chemistry of cMOFs makes the controlled synthesis and advanced characterization of high-quality thin films, particularly challenging. Herein, we report the development of a simplified synthesis method to grow "face-on" and "edge-on" cMOF nanofilms on substrates, and the establishment of operando characterization methodology using atomic force microscopy and X-ray, thereby demonstrating the relationship between the soft structure of surface-mounted oriented networks and their characteristic conductive functions. As a result, crystallinity of cMOF nanofilms with a thickness down to a few nanometers is obtained, the possible growth mechanisms are proposed, and the interesting anisotropic softness-dependent conducting properties (over 2 orders of magnitude change) of the cMOF are also illustrated.

Enhancing Fire Safety and Softness: Efficacy of Ethanolamine Polyphosphate as a Fire Retardant for Textiles.

The rising awareness of fire safety among consumers has driven the demand for fire retardants (FRs) that are both cost-effective and efficient across various industries, particularly in textiles. Traditional FRs often compromise fabric softness, resulting in undesirable tactile texture and stiffness changes. While the external addition of softeners can mitigate the stiffness, it may introduce issues such as a greasy texture and increased flammability. This study introduces ethanolamine polyphosphate (EAPP), an innovative organic polyphosphate, as an effective fire retardant that preserves the softness of textiles. Comprehensive evaluations are conducted on EAPP-treated textiles, revealing significant improvements in fire retardancy without compromising fabric quality. EAPP treatment (15 wt.% aqueous solutions) increases the limiting oxygen index (LOI) of pure cotton textiles from 17% to 36% and significantly reduces the peak heat release rate (pHRR) and total smoke rate (TSR) as measured by cone calorimetry. Unlike conventional FR products that form FR-salt crystal particles on the fabric surface after drying, EAPP forms a smooth FR protective layer on the fabric, enhancing mechanical fastness and maintaining tactile qualities. These findings highlight EAPP's potential as a non-washing durable, spray-on fire retardant solution for textiles, combining safety with user comfort.

Surface Superconductivity with High Transition Temperatures in Layered CanBn+1Cn+1 Films.

Proposed by Ginzberg nearly 60 years ago, surface superconductivity refers to the emergent phenomenon that the electrons on or near the surface of a material becomes superconducting despite its bulk is nonsuperconducting. Here, based on first-principles calculations within density functional theory, we predict that the superconducting transition temperature Tc at the surfaces of CanBn+1Cn+1 (n = 1, 2, 3, ...) films can be drastically enhanced to ∼90 K from 8 K for bulk CaBC. Our detailed analyses reveal that structural symmetry reduction at surfaces induces pronounced carrier self-doping into the surface B-C layer of the films and shifts the σ-bonding states toward the Fermi level; furthermore, the in-plane stretching modes of the surface layers experience significant softening. These two effects work collaboratively to strongly enhance the electron-phonon coupling, which in turn results in much higher Tc values than the McMillian limit. These findings point to new material platforms for realizing unusually high-Tc surface superconductivity.

Softness enhanced macrophage-mediated therapy of inhaled apoptotic-cell-inspired nanosystems for acute lung injury.

Engineered nanosystems offer a promising strategy for macrophage-targeted therapies for various diseases, and their physicochemical parameters including surface-active ligands, size and shape are widely investigated for improving their therapeutic efficacy. However, little is known about the synergistic effect of elasticity and surface-active ligands. Here, two kinds of anti-inflammatory N-acetylcysteine (NAC)-loaded macrophage-targeting apoptotic-cell-inspired phosphatidylserine (PS)-containing nano-liposomes (PSLipos) were constructed, which had similar size and morphology but different Young's modulus (E) (H, ~ 100 kPa > Emacrophage vs. L, ~ 2 kPa < Emacrophage). Interestingly, these PSLipos-NAC showed similar drug loading and encapsulation efficiency, and in vitro slow-release behavior of NAC, but modulus-dependent interactions with macrophages. Softer PSLipos-L-NAC could resist macrophage capture, but remarkably prolong their targeting effect period on macrophages via durable binding to macrophage surface, and subsequently more effectively suppress inflammatory response in macrophages and then hasten inflammatory lung epithelial cell wound healing. Especially, pulmonary administration of PSLipos-L-NAC could significantly reduce the inflammatory response of M1-like macrophages in lung tissue and promote lung injury repair in a bleomycin-induced acute lung injury (ALI) mouse model, providing a potential therapeutic approach for ALI. The results strongly suggest that softness may enhance ligand-directed macrophage-mediated therapeutic efficacy of nanosystems, which will shed new light on the design of engineered nanotherapeutics.

Changes in the Form Factor and Size Distribution of Nanogels in Crowded Environments.

Particle size disparities suppress crystallization. However, soft deformable nanogels can change the size of the larger particles in suspension and crystallize even at a high initial size-polydispersity. Using neutron scattering with contrast variation, the response of individual nanogels in crowded environments was probed, and an increase of the parameter describing size-polydispersity was found, which is often interpreted as deformation. Here, computer simulations are used to generate deformed nanogels and the corresponding form factor. The data are fitted with the spherical model used to analyze scattering data. The fits show the same qualitative increase of the parameter related to the size-polydispersity with increasing particle deformation. Starting from the simulated deformed spheres, we also reproduce experimental scattering data. A further analysis of the particle shows that the size disparities between nanogels do not increase significantly. In contrast, their shapes strongly vary from one nanogel to the other.

Staphylococcal Enterotoxin C2 Mutant-Induced Antitumor Immune Response Is Controlled by CDC42/MLC2-Mediated Tumor Cell Stiffness.

As a biological macromolecule, the superantigen staphylococcal enterotoxin C2 (SEC2) is one of the most potent known T-cell activators, and it induces massive cytotoxic granule production. With this property, SEC2 and its mutants are widely regarded as immunomodulating agents for cancer therapy. In a previous study, we constructed an MHC-II-independent mutant of SEC2, named ST-4, which exhibits enhanced immunocyte stimulation and antitumor activity. However, tumor cells have different degrees of sensitivity to SEC2/ST-4. The mechanisms of immune resistance to SEs in cancer cells have not been investigated. Herein, we show that ST-4 could activate more powerful human lymphocyte granule-based cytotoxicity than SEC2. The results of RNA-seq and atomic force microscopy (AFM) analysis showed that, compared with SKOV3 cells, the softer ES-2 cells could escape from SEC2/ST-4-induced cytotoxic T-cell-mediated apoptosis by regulating cell softness through the CDC42/MLC2 pathway. Conversely, after enhancing the stiffness of cancer cells by a nonmuscle myosin-II-specific inhibitor, SEC2/ST-4 exhibited a significant antitumor effect against ES-2 cells by promoting perforin-dependent apoptosis and the S-phase arrest. Taken together, these data suggest that cell stiffness could be a key factor of resistance to SEs in ovarian cancer, and our findings may provide new insight for SE-based tumor immunotherapy.

Serum amylase on postoperative day one is a strong predictor of pancreatic fistula after pancreaticoduodenectomy: a retrospective cohort.

Background/aim: Early identification of patients at risk for developing postoperative pancreatic fistula (POPF) after pancreaticoduodenectomy (PD) may facilitate drain management. In this context, it was aimed to examine the efficiency of the serum amylase (SA) value on postoperative day (PoD) 1 in predicting the occurrence of POPF. Materials and methods: A total of 132 patients who underwent PD were studied. Occurrences of POPF were classified according to the International Study Group on Pancreatic Fistula classification as a biochemical leak (BL) or clinically relevant grade b/c POPF (CR-POPF). Receiver operating characteristic analysis identified a threshold value of SA on PoD 1 associated with POPF formation. Results: Overall, 66 (50%) patients had POPF, including 51 (38.7%) with BL and 15 with CR-POPF (11.3%). The threshold value of SA associated with the development of POPF was 120 IU/L (odds ratio [OR]: 3.20; p = 0.002). In the multivariate analysis, independent POPF risk factors were SA ≥120 IU/L, soft pancreatic texture, and high-risk pathology (i.e., duodenal, biliary, ampullary, islet cell, and benign tumors); SA ≥120 IU/L outperformed soft pancreatic texture and high-risk pathology in predicting POPF, respectively (OR: 2.22; p = 0.004 vs. OR: 1.37; p = 0.012 vs. OR: 1.35; p = 0.018). In a subset analysis according to gland texture (soft vs. hard), patients with soft pancreatic texture exhibited a significantly higher incidence of POPF (63.4% vs. 34.4%) and SA ≥120 IU/L (52.1% vs. 27.9%); SA <120 IU/L had a negative predictive value of 82.5% for developing POPF in patients with hard pancreatic texture (OR: 4.28, p = 0.028). Conclusion: A SA value ≥120 IU/L on the day after PD, which is the strongest predictor for POPF, can be used as a biomarker of the occurrence of POPF. The advantage of SA measurement is that it can contribute to identifying suitable patients for early drain removal.

Analysis in silico of chemical reactivity employing the local hyper-softness in some classic aromatic compounds, boron aromatic clusters and all-metal aromatic clusters.

In the current work, the authors analyzed and compared the chemical behavior of some (anti)aromatic compounds. The species selected are benzene and cyclobutadiene as the aromatic and antiaromatic classical examples, respectively. Next, the anion Al 4 2 - , which is the first all-metal molecule catalogued as aromatic and its non-metallic isoelectronic analog, B 4 2 - were also analyzed. The antiaromatic clusters Al 4 4 - and B 4 4 - were studied in form of lithium salts. And the end, the non-planar B 12 boron cluster and its isoelectronic analogs ( B 11 Be - and B 11 C + ) were considered for being analyzed under the same criterium. The analysis was realized employing the following descriptors: molecular electrostatic potential and local hyper-softness to get insights concerning local reactivity when facing reagents leading to ionic or covalent interactions. The results show that all the molecules analyzed presented some specific variations in their respective local reactivity despite being labeled as aromatic compounds. This analysis provides a notion that the local reactivity is more based on the nature of the atoms and the molecular geometry than the aromatic character by itself.

The role of Co2+cation addition in enhancing the AC heat induction power of (CoxMn1-x)Fe2O4superparamagnetic nanoparticles.

The physical role of magnetically semi-hard Co2+cation addition in enhancing the AC heat induction temperature (TAC) or specific loss power (SLP) of solid (CoxMn1-x)Fe2O4superparamagnetic iron oxide nanoparticles (SPIONPs) was systematically investigated at the biologically safe and physiologically tolerable range ofHAC(HAC,safe= 1.12 × 109A m-1s-1,fappl= 100 kHz,Happl= 140 Oe (11.2 A m-1)) to demonstrate which physical parameter would be the most critical and dominant in enhancing theTAC(SLP) of SPIONPs. According to the experimentally and theoretically analyzed results, it was clearly demonstrated that the enhancement of magnetic anisotropy (Ku)-dependent AC magnetic softness including the Néel relaxation time constantτN(≈τeff, effective relaxation time constant), and its dependent out-of-phase magnetic susceptibilityχ″primarily caused by the Co2+cation addition is the most dominant parameter to enhance theTAC(SLP). This clarified result strongly suggests that the development of new design and synthesis methods enabling to significantly enhance theKuby improving the crystalline anisotropy, shape anisotropy, stress (magnetoelastic) anisotropy, thermally-induced anisotropy, and exchange anisotropy is the most critical to enhance theTAC(SLP) of SPIONPs at theHAC,safe(particularly at the lowerfappl< 120 kHz) for clinically safe magnetic nanoparticle hyperthermia.

Friction and Adhesion Govern Yielding of Disordered Nanoparticle Packings: A Multiscale Adhesive Discrete Element Method Study.

Recent studies have demonstrated that amorphous materials, from granular packings to atomic glasses, share multiple striking similarities, including a universal onset strain level for yield. This is despite vast differences in length scales and in the constituent particles' interactions. However, the nature of localized particle rearrangements is not well understood, and how local interactions affect overall performance remains unknown. Here, we introduce a multiscale adhesive discrete element method to simulate recent novel experiments of disordered nanoparticle packings indented and imaged with single nanoparticle resolution. The simulations exhibit multiple behaviors matching the experiments. By directly monitoring spatial rearrangements and interparticle bonding/debonding under the packing's surface, we uncover the mechanisms of the yielding and hardening phenomena observed in experiments. Interparticle friction and adhesion synergistically toughen the packings and retard plastic deformation. Moreover, plasticity can result from bond switching without particle rearrangements. These results furnish insights for understanding yielding in amorphous materials generally.

Adsorption Characteristics of Gas Molecules Adsorbed on Graphene Doped with Mn: A First Principle Study.

Herein, the adsorption characteristics of graphene substrates modified through a combined single manganese atom with a vacancy or four nitrogen to CH2O, H2S and HCN, are thoroughly investigated via the density functional theory (DFT) method. The adsorption structural, electronic structures, magnetic properties and adsorption energies of the adsorption system have been completely analyzed. It is found that the adsorption activity of a single vacancy graphene-embedded Mn atom (MnSV-GN) is the largest in the three graphene supports. The adsorption energies have a good correlation with the integrated projected crystal overlap Hamilton population (-IpCOHP) and Fermi softness. The rising height of the Mn atom and Fermi softness could well describe the adsorption activity of the Mn-modified graphene catalyst. Moreover, the projected crystal overlap Hamilton population (-pCOHP) curves were studied and they can be used as the descriptors of the magnetic field. These results can provide guidance for the development and design of graphene-based single-atom catalysts, especially for the support effect.

The Azide-Allene Dipolar Cycloaddition: Is DFT Able to Predict Site- and Regio-Selectivity?

The site- and regio-selectivity of thermal, uncatalysed 1,3-dipolar cycloadditions between arylazides and mono- or tetra-substituted allenes with different electronic features have been investigated by both conceptual (reactivity indices) and computational (M08-HX, ωB97X-D, and B3LYP) DFT approaches. Both approaches show that these cycloadditions follow a nonpolar one-step mechanism. The experimental site- and regio-selectivity of arylazides towards methoxycarbonyl- and sulfonyl-allenes as well as tetramethyl- and tetrafluoro-allenes was calculated by DFT transition state calculations, achieving semiquantitative agreement to both previous and novel experimental findings. From the mechanistic standpoint, 1H-NMR evidence of a methylene-1,2,3-triazoline intermediate reinforces the reliability of the computational scheme.

[Study on Influencing Factors of the Tip Softness of Epidural Anesthesia Catheter].

This article aims to study the factors affecting the flexibility of the tip of an epidural anesthesia catheter. The flexibility of the tip of the epidural anesthesia catheter was tested with a softness tester from four aspects:raw materials, tip structure, tip processing technology, and the outer diameter of the catheter. Highly flexible and malleable polymer material with a smooth tip, the tip softening process and the proper outer diameter can effectively improve the tip flexibility of the epidural anesthesia catheter.

The Discovery of a Putative Allosteric Site in the SARS-CoV-2 Spike Protein Using an Integrated Structural/Dynamic Approach.

SARS-CoV-2 has caused the largest pandemic of the twenty-first century (COVID-19), threatening the life and economy of all countries in the world. The identification of novel therapies and vaccines that can mitigate or control this global health threat is among the most important challenges facing biomedical sciences. To construct a long-term strategy to fight both SARS-CoV-2 and other possible future threats from coronaviruses, it is critical to understand the molecular mechanisms underlying the virus action. The viral entry and associated infectivity stems from the formation of the SARS-CoV-2 spike protein complex with angiotensin-converting enzyme 2 (ACE2). The detection of putative allosteric sites on the viral spike protein molecule can be used to elucidate the molecular pathways that can be targeted with allosteric drugs to weaken the spike-ACE2 interaction and, thus, reduce viral infectivity. In this study, we present the results of the application of different computational methods aimed at detecting allosteric sites on the SARS-CoV-2 spike protein. The adopted tools consisted of the protein contact networks (PCNs), SEPAS (Affinity by Flexibility), and perturbation response scanning (PRS) based on elastic network modes. All of these methods were applied to the ACE2 complex with both the SARS-CoV2 and SARS-CoV spike proteins. All of the adopted analyses converged toward a specific region (allosteric modulation region [AMR]), present in both complexes and predicted to act as an allosteric site modulating the binding of the spike protein with ACE2. Preliminary results on hepcidin (a molecule with strong structural and sequence with AMR) indicated an inhibitory effect on the binding affinity of the spike protein toward the ACE2 protein.

Model Predictive Controller Based on Online Obtaining of Softness Factor and Fusion Velocity for Automatic Train Operation.

This paper develops an improved model predictive controller based on the online obtaining of softness factor and fusion velocity for automatic train operation to enhance the tracking control performance. Specifically, the softness factor of the improved model predictive control algorithm is not a constant, conversely, an improved online adaptive adjusting method for softness factor based on fuzzy satisfaction of system output value and velocity distance trajectory characteristic is adopted, and an improved whale optimization algorithm has been proposed to solve the adjustable parameters; meanwhile, the system output value for automatic train operation is not sampled by a normal speed sensor, on the contrary, an improved online velocity sampled method for the system output value based on a fusion velocity model and an intelligent digital torque sensor is applied. In addition, the two improved strategies proposed take the real-time storage and calculation capacities of the core chip of the controller into account. Therefore, the proposed improved strategies (I) have good performance in tracking precision, (II) are simple and easily conducted, and (III) can ensure the accomplishing of computational tasks in real-time. Finally, to verify the effectiveness of the improved model predictive controller, the Matlab/simulink simulation and hardware-in-the-loop simulation (HILS) are adopted for automatic train operation tracking control, and the tracking control simulation results indicate that the improved model predictive controller has better tracking control effectiveness compared with the existing traditional improved model predictive controller.

Analysis of the Gas Phase Acidity of Substituted Benzoic Acids Using Density Functional Concepts.

A theoretical study of the effect of the substituent Z on the gas phase acidity of substituted benzoic acids ZC6H4COOH in terms of density functional theory descriptors (chemical potential, softness and Fukui function) is presented. The calculated gas phase ΔacidG° values obtained were close to the experimental ones reported in the literature. The good relationship between the ΔacidG° values and the electronegativity of ZC6H4COOH and its fragments, suggested a better importance of the inductive than polarizability contributions. The balance of inductive and resonance contributions of the substituent in the acidity of substituted benzoic acids showed that the highest inductive and resonance effects were for the -SO2CF3 and -NH2 substituents in the para- and ortho-position, respectively. The Fukui function confirmed that the electron-releasing substituent attached to the phenyl ring of benzoic acid decreased the acidity in the trend ortho > meta > para, and the electron-withdrawing substituent increased the acidity in the trend ortho < meta < para.

Quantitative structure-activity relationship in the photodegradation of azo dyes.

The photolysis characteristics of azo dyes are critically important in environmental pollution control, dye-sensitized solar cells, and dyeing-related industries. However, there is still lack of quantitative relationship between the structures of azo dyes and their photolysis characteristics. To address this issue, the photolysis of 22 azo dyes were conducted side by side at three pH (4.0, 6.0, 9.0). The obtained pseudo-first order photodegradation rate constants (k1) were processed with meta-analysis. Statistically, the hydrazone tautomer had a smaller excitation energy and was easier to undergo photolysis than the azo tautomer. The ortho-substituted sulfonate groups had an obvious protective effect on the photostability of azo dyes. The softness (s), the most positive and negative partial charge on a carbon atom (qC+, qC-) were found to be crucial descriptors in the establishment of QSAR models for the photostability of azo dyes. The QSAR model at pH 9.0 was robust for predicting the photostability of azo dyes under UV irradiation. N2-purging experiments and quantum chemical computation verified that the cleavage of azo bond was not a result of direct photolysis but was caused by the attack of photoinduced reactive oxygen species. The results here are helpful for the design of more stable azo dyes or the selection of suitable approaches for the treatment of dye-contaminated water bodies.

Brain networks underlying tactile softness perception: A functional magnetic resonance imaging study.

Humans are adept at perceiving physical properties of an object through touch. Tangible object properties can be categorized into two types: macro-spatial properties, including shape and orientation; and material properties, such as roughness, softness, and temperature. Previous neuroimaging studies have shown that roughness and temperature are extracted at nodes of a network, such as that involving the parietal operculum and insula, which is different from the network engaged in processing macro-spatial properties. However, it is unclear whether other perceptual dimensions pertaining to material properties engage the same regions. Here, we conducted a functional magnetic resonance imaging study to test whether the parietal operculum and insula were involved in extracting tactually-perceived softness magnitude. Fifty-six healthy right-handed participants estimated perceived softness magnitude using their right middle finger. We presented three stimuli that had the same shape but different compliances. The force applied to the finger was manipulated at two levels. Classical mass-univariate analysis showed that activity in the parietal operculum, insula, and medial prefrontal cortex was positively associated with perceived softness magnitude, regardless of the applied force. Softness-related activity was stronger in the ventral striatum in the high-force condition than in the low-force condition. The multivariate voxel pattern analysis showed higher accuracy than chance levels and control regions in the parietal operculum/insula, postcentral gyrus, posterior parietal lobule, and middle occipital gyrus. These results indicate that a distributed set of the brain regions, including the parietal operculum and insula, is involved in representing perceived softness.

A reference-free stockholder partitioning method based on the force on electrons.

We argue that when one divides a molecular property into atom-in-a-molecule contributions, one should perform the division based on the property density of the quantity being partitioned. This is opposition to the normal approach, where the electron density is given a privileged role in defining the properties of atoms-in-a-molecule. Because partitioning each molecular property based on its own property density is inconvenient, we design a reference-free approach that does not (directly) refer atomic property densities. Specifically, we propose a stockholder partitioning method based on relative influence of a molecule's atomic nuclei on the electrons at a given point in space. The resulting method does not depend on an "arbitrary" choice of reference atoms and it has some favorable properties, including the fact that all of the electron density at an atomic nucleus is assigned to that nucleus and the fact all the atoms in a molecule decay at a uniform asymptotic rate. Unfortunately, the resulting model is not easily applied to spatially degenerate ground states. Furthermore, the practical realizations of this strategy that we tried here gave disappointing numerical results. © 2017 Wiley Periodicals, Inc.