Submission Research Articles

Collagen fibers within skeletal muscle extracellular matrix dynamically change their alignment in a stretch-dependent fashion

Collagen fiber architecture within the skeletal muscle extracellular matrix (ECM) contributes to muscle passive mechanical properties. There is evidence that collagen fibers change their alignment during muscle lengthening (stretching). Thus, the goal of this study was to characterize the dynamic changes of collagen fiber alignment in the muscle ECM during muscle stretching, and to assess the relationship between dynamic collagen re-alignment and muscle passive mechanics. We hypothesized that collagen fibers increase their alignment as the muscle is stretched, and that increased collagen alignment in stretched muscle is correlated to higher elastic stiffness. Extensor digitorum longus (EDL), soleus, and diaphragm muscles were collected from wildtype (WT) and D2.mdx (MDX) mice of 48-52 weeks of age. Muscles underwent a series of twitches to determine the optimum length (Lo) for isometric contraction, and then were decellularized to isolate the muscle ECM. Decellularized muscles (DCMs) were then mechanically tested using a series of stress-relaxation tests at 5% increments from 85% to 115% length relative to Lo. Elastic stiffness was measured as the slope of the tangent line on the stress-strain curve following stress-relaxation. Following mechanical testing, DCMs were imaged using second harmonic generation microscopy to visualize collagen alignment across the range of lengths used in mechanical testing. Collagen alignment was reported as an alignment index on a scale of 0 (perfect unalignment) to 1 (perfect alignment). We found that MDX diaphragm DCMs were less stiff than WT (WT: 910.2±586.7, MDX: 238±168.7, p=0.0041), but there were no significant differences in stiffness between WT and MDX EDL and soleus DCMs. We also observed a significant effect of stretch on collagen alignment in all DCMs tested (Diaphragm: p=0.0071, EDL: p=0.0004, soleus: p<0.0001). Interestingly, the collagen fibers of the epimysium, the outermost layer of the muscle ECM, were more aligned in WT diaphragm DCMs than in MDX (WT 85%: 0.672±.14, MDX 85%: 0.344±0.16, p=0.0027; WT 115%: 0.783±0.04, MDX 115%: 0.480±0.19, p=0.0036). Finally, we found a significant positive correlation between the alignment and elastic stiffness at 110% Lo across all DCMs (p=0.0038, R2=0.1713). These data indicate that collagen fibers dynamically re-align as muscle is stretched. Additionally, increased collagen fiber alignment is associated with higher passive stiffness in the decellularized muscle ECM. Overall, we find that dynamic architectural changes in the muscle ECM contribute to passive mechanical behavior during a muscle stretch. This work was supported by a grant from the NIH NIAMS (R01-AR079545). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Synergistic Functional Muscle Networks Reveal the Passivity Behavior of the Upper-Limb in Physical Human-Robot Interaction

Synergistic Functional Muscle Networks Reveal the Passivity Behavior of the Upper-Limb in Physical Human-Robot Interaction

Investigation on the Passive Behavior of Ti-9Mn Alloy in 3.5 wt% NaCl Solution

Ti-9Mn alloy, widely used in aerospace and hydrogen storage, was recently introduced for marine and offshore structures because of its competitive mechanical characteristics. In this study, passive behavior of Ti-9Mn alloy was compared to the commercially pure titanium (cp-Ti). Ti-9Mn exhibited lower charge-transfer resistance than cp-Ti. Under steady-state condition, resistivity at metal/oxide film interface for Ti-9Mn alloy, which increased as fa unction of applied passive potential in range of 0.5 to 1.5 VSCE, was found to be lower than that of cp-Ti. Complex-capacitance (C ∞) value for Ti-9Mn alloy was higher than that of cp-Ti. Presence of Mn in the alloy induced significant increase in current density when potential exceeds 1.5 VSCE. Corrosion current density of Ti-9Mn (16.2 ± 4.0 nA cm−2) was three times higher than that of cp-Ti (4.57 ± 0.7 nA cm−2) after 21 days immersion in 3.5 wt% NaCl. The study may allow us to realize the full potential passivation behavior of Ti-9Mn for future marine and offshore applications.

New insights into the mechanism causing the loss of anti-corrosion property of superhydrophobic titanium surfaces

In this paper, we provide new insights into the mechanism causing the loss of anti-corrosion property of superhydrophobic titanium (SHP Ti) during potentiodynamic polarization (PDP) measurements. The water contact angle and sliding angle values of the SHP Ti, produced by a facile two-step process: anodizing and coating, were >160° and 6±2°, respectively. The anodization of Ti resulted in randomly distributed micro-clusters of TiO2-xCly covering the Ti surface homogeneously while the low surface energy organic coatings were inhomogeneous in coverage and specifically distributed over the micro-clusters alone of the anodized titanium surface. The electrochemical impedance (EIS) analysis of the SHP CP-Ti samples has shown more than an order of magnitude improvement in their barrier /polarization resistance (Rp) values at ∼ 100 MΩ.cm2 suggesting the effectiveness of the SHP coatings as a barrier against corrosion in neutral chloride environments. However, the Rp values (∼ 10 M Ω.cm2) of the SHP coatings obtained from the PDP analysis were an order of magnitude lower than the Rp values derived from the EIS. SHP CP-Ti samples showed dual passive range behaviour with an initial narrow passive region due to the porous anodized TiO2-xCly layer while the later stage passivity due to the barrier TiO2 layer, where the outer anodized porous TiO2-xCly layer was less effective against corrosion in neutral chloride media. Detailed analysis showed that in PDP, the sample lost its SHP because of the permeation of electrolyte into the hierarchical surface, due to its sensitivity to polarization, owing to the lower thickness of the organic layers. The mechanism involved in the loss of SHP and the limitation of the PDP technique for the corrosion analysis of SHP / organic coatings on metal surfaces is highlighted.

Electrochemical insight into the passivity and corrosion of 316 L stainless steel fabricated through wire arc additive manufacturing

This study explores the microstructure of AISI 316L stainless steel fabricated by wire arc additive manufacturing (WAAM) and establishes correlations with its passivity and corrosion characteristics in a 0.9 wt% NaCl solution, while making comparisons with the wrought alloy counterpart. The WAAM-fabricated alloy demonstrates a favorable chemical composition in comparison to the wrought alloy, exhibiting a heterogeneous microstructure comprised of residual delta ferrite within the austenitic matrix. The pitting vulnerability of the WAAM-printed alloy is observed to be lower than that of the wrought counterpart, a phenomenon further investigated through passive film behavior analysis. Mott-Schottky analysis and the point defect model (PDM) revealed the development of a less defective passive layer on the WAAM-fabricated alloy, enhancing overall passivity and electrochemical response, attributed to the interplay between microstructural features and chemical composition.

The inhibitor effect of migrating corrosion inhibitors on Q235 steel in high alkaline environment under cathodic polarization

PurposeThis study aims to investigate the corrosion inhibitor effect of migrating corrosion inhibitor (MCI) on Q235 steel in high alkaline environment under cathodic polarization.Design/methodology/approachThis study investigated the electrochemical characteristics of Q235 steel with and without MCI by polarization curve and electrochemical impedance spectroscopy. Besides, the surface composition of Q235 steel under different environments was analyzed by X-ray photoelectron spectroscopy. In addition, the migration characteristic of MCI and the adsorption behavior of MCI under cathodic polarization were studied using Raman spectroscopy.FindingsDiethanolamine (DEA) and N, N-dimethylethanolamine (DMEA) can inhibit the increase of Fe(II) in the oxide film of Q235 steel under cathodic polarization. The adsorption stability of DMEA film was higher under cathodic polarization potential, showing a higher corrosion inhibition ability. The corrosion inhibition mechanism of DEA and DMEA under cathodic polarization potential was proposed.Originality/valueThe MCI has a broad application prospect in the repair of damaged reinforced concrete due to its unique migratory characteristics. The interaction between MCIs, rebar and concrete with different compositions has been studied, but the passivation behavior of the steel interface in the presence of both the migrating electric field and corrosion inhibitors has been neglected. And it was investigated in this paper.

Determinants of innovation performance: influence of knowledge-oriented leadership, knowledge sharing and organizational justice

Purpose Due to the vital role of innovation for firms to respond to the change and achieve competitive advantage, the purpose of this study is to investigate the influence of knowledge-oriented leadership (KOL) on innovation performance via the mediating role of knowledge sharing (KS). This study also explores the moderating role of organizational justice in the relationship between KS and innovation performance. Design/methodology/approach Analysis of moment structures and structural equation modeling are applied to examine the relationship among the latent factors in the proposed research model using data collected from 335 participants in 121 manufacturing and service firms in Vietnam. Findings The findings revealed that KOL serves as a key precursor to foster innovation performance directly or indirectly through active and passive KS behaviors. In addition, the paper highlights the moderating role of organizational justice in strengthening the impact of KS activities on innovation performance. Research limitations/implications By highlighting the important role of KOL for stimulating KS behaviors, this paper provides a valuable understanding and novel approach for firms to improve innovation performance. The research findings support the idea that building a climate of justice is crucial to enhance the effects of KS on innovation performance. Originality/value This study contributes to bridging the research gaps in the literature and advances the insights of how KOL directly and indirectly stimulates innovation performance via mediating roles of active and passive KS processes under the climate of justice.

The influence of microstructural evolutions on electrochemical corrosion and passive behavior in precipitation-strengthened high-entropy alloys

Effects of microstructural evolutions on electrochemical corrosion properties and passive film characteristics of precipitation-strengthened (Ni2Co2FeCr)92Al4Nb4 high-entropy alloys (HEAs) were investigated in a saline environment. Compared with single-phase FCC alloys, the appearance of nano-sized L12 particles increases the metastable pitting activities and slightly reduces the pitting potential, while the lamellar D019 phase further deteriorates the localized corrosion resistance. The chemical composition and oxide state of passive films are closely related to the different precipitation scenarios. The corrosion morphologies of the single-phase and L12-strengthened alloys are dominated by pitting, whereas the intergranular corrosion (IGC) and intragranular dealloying-like corrosion occur in the D019-strengthened alloy.

A comparative study on the passive film and SCC behavior of Ti-6Al-3Nb-2Zr-1Mo alloy at various test temperatures in simulated seawater

In this work, the electrochemical and stress corrosion cracking (SCC) behavior of Ti-6Al-3Nb-2Zr-1Mo alloy in simulated seawater at various solution temperatures were systematically studied. Results show rising test temperature increases the point defect density in passive film and deteriorates the stability. Therefore, SCC is promoted by localized anodic dissolution (AD). At 25 °C, SCC initiates in αp phase, and β phase hinders SCC propagation on account of the lower electrochemical activity induced by element segregation. While at 4 °C, the SCC propagation rate is higher than that at 25 °C, as the SCC propagation resistance of β phases decreases.

Passive social networking sites use and disordered eating behaviors in adolescents: The roles of upward social comparison and body dissatisfaction and its sex differences

Previous research has indicated a link between social networking site (SNS) use and eating behaviors, but the underlying mechanisms have not been well explored. This study investigated the role of upward social comparison and body dissatisfaction in the relationship between passive SNS use and disordered eating (DE) behaviors, as well as sex differences. A total of 744 middle school students (51.6% female, Mage = 12.87 years, SD = 0.68) completed self-report questionnaires regarding passive SNS use, upward social comparison, body dissatisfaction, and DE behaviors. Results revealed that: 1) girls reported significantly higher levels of passive SNS use, body dissatisfaction, and DE behaviors than boys; 2) passive SNS use was a significant predictor of DE behaviors both sexes; 3) body dissatisfaction mediated the relationship between passive SNS use and DE behaviors for girls; 4) the chain mediating effects of upward social comparison and body dissatisfaction between passive SNS use and DE behaviors were found only among adolescent girls; 5) Compared to boys, body dissatisfaction in girls is more significantly related to DE behaviors, and upward social comparison is more closely related to body dissatisfaction in girls. These findings suggest that passive SNS use, rather than general SNS use, was related to body dissatisfaction and eating concerns. Interventions targeting specific passive SNS users may be an effective avenue for the prevention and management of body-related concerns and disordered eating behavior in adolescent girls.

Attachment-like behavioral expressions to humans in puppies are related to oxytocin and cortisol: A comparative study of Akitas and Labrador Retrievers

This study investigated the relationship between urinary hormone concentrations and attachment-related behaviors in two dog breeds, the Akitas and Labrador Retrievers, to elucidate the hormonal and behavioral mechanisms underlying domestication and interspecies attachment to humans. By measuring cortisol and oxytocin concentrations, and conducting the Strange Situation Test (SST), we aimed to investigate breed differences in endocrine secretions associated with domestication and how these differences influence dog behavior toward humans. Our results showed significant breed differences in urinary cortisol concentrations, with Akitas exhibiting higher levels than Labrador Retrievers. This suggests a breed-specific stress response related to genetic proximity to wolves. However, oxytocin concentrations did not differ significantly, which suggests a complex interplay between factors influencing the domestication process and the formation of attachment behaviors. Behavioral observations during the SST revealed breed-specific patterns, with Labrador Retrievers showing more playful and attachment-like behaviors and Akitas showing more exploratory and passive behaviors. The study found correlations between hormones and behaviors within breeds, particularly in Labrador Retrievers, where oxytocin concentrations were associated with attachment-like behaviors, and cortisol concentrations reflected individual differences in physical activity rather than stress responses to social situations. These findings contribute to the understanding of the evolutionary and adaptive processes underlying the ability of domestic dogs to form close relationships with humans while highlighting the role of hormonal mechanisms in mediating attachment behaviors and the influence of breed-specific genetic backgrounds on these processes.

Corrosion behavior of two Cu‐based shape memory alloys in NaCl solution: An electrochemical study

AbstractThe corrosion behavior of two different Cu–Al–Mn–Ni alloys, pseudoelastic and pseudoplastic, was studied in a 0.6 M sodium chloride aqueous solution by monitoring the open circuit potential for 100 h and characterizing the resulting corrosion products. Electrochemical impedance spectroscopy analysis detected three processes related to the electrochemical double layer, a passive film and a diffusive contribution associated with the dissolution/precipitation of corrosion products. Potentiodynamic scans revealed a cathodically controlled corrosion mechanism and the presence of active–passive behavior at anodic potentials for both alloys studied. Polarization of the samples at selected potentials in the anodic branch allowed the investigation of the reactions involved, highlighting an improved corrosion resistance of the pseudoelastic alloy. The corrosion rates of the pseudoelastic and pseudoplastic alloys, after 100 h of immersion, were determined to be 0.007 and 0.011 mmpy, respectively. The post‐experiment characterization was carried out by means of scanning electron microscopy, micro‐Raman spectroscopy and X‐ray diffraction, supporting the electrochemical results.

Microstructural and electrochemical behaviour of severely surface-deformed 316L steel manufactured by conventional and selective laser melting routes

This study thoroughly examines the influence of conventional and selective laser melting (SLM) routes and surface mechanical attrition treatment (SMAT) on the microstructural and electrochemical properties of 316L steel. Compared to wrought specimens, the SLM specimens exhibit significantly smaller grains (∼41 vs. ∼83 µm) and higher dislocation density (∼7.2 × 1013 vs. ∼3.7 × 1012 m−2). Both specimens show nearly doubled surface hardness after SMAT, with the SLM surface displaying a ∼30 nm grain size and minimal α’ phase. The microstructure significantly influences passivation and corrosion behaviour. The SLM specimens exhibit superior electrochemical characteristics to wrought counterparts in SMATed (0.00299 mmpy) and non-SMATed (0.00771 mmpy) conditions. SMAT effectively eliminates surface porosity, enhancing the passivation and corrosion resistance of SLM steel.

Prefrontal cortical dynorphin peptidergic transmission constrains threat-driven behavioral and network states

Prefrontal cortical (PFC) circuits provide top-down control of threat reactivity. This includes ventromedial PFC (vmPFC) circuitry, which plays a role in suppressing fear-related behavioral states. Dynorphin (Dyn) has been implicated in mediating negative affect and maladaptive behaviors induced by severe threats and is expressed in limbic circuits, including the vmPFC. However, there is a critical knowledge gap in our understanding of how vmPFC Dyn-expressing neurons and Dyn transmission detect threats and regulate expression of defensive behaviors. Here, we demonstrate that Dyn cells are broadly activated by threats and release Dyn locally in the vmPFC to limit passive defensive behaviors. We further demonstrate that vmPFC Dyn-mediated signaling promotes a switch of vmPFC networks to a fear-related state. In conclusion, we reveal a previously unknown role of vmPFC Dyn neurons and Dyn neuropeptidergic transmission in suppressing defensive behaviors in response to threats via state-driven changes in vmPFC networks.

Объявление официального предостережения в условиях УИС: проблемные вопросы законодательного регулирования

In the presented article, the author examines the current situation in the field of law enforcement in institutions of the penal enforcement system. Attention is drawn to the special need to prevent penitentiary offenses, in connection with which the author focuses on such a form of preventive action as the announcement of an official warning. The article provides an overview of the scientific development of the topic, and concludes that it is insufficiently studied in relation to the needs of the penal enforcement system. The conducted systematic analysis of certain provisions of federal legislation allowed us to identify the following problematic points: despite the significant preventive potential inherent in Article 17.1 of the Penal Enforcement Code of the Russian Federation, which allows including not only convicts, suspects and accused, but also other persons who can visit institutions executing punishments among the objects of preventive work its full-fledged implementation rests on the content of some articles of the Federal Law “On the Basics of the crime Prevention System in the Russian Federation”, the unfortunate wording of which limits the preventive resource of the Penal Enforcement Code, reducing preventive efforts to work with a special agent. The author also identifies and justifies the need to supplement the title of Article 20 of the Federal Law “On the Basics of the crime prevention system in the Russian Federation” with the word “inaction”, since this form of passive behavior is quite common among special agents and acts as a condition for committing various offenses. Taking into account the above, the author proposes amendments to federal legislation that make it possible to optimize preventive work in institutions that carry out punishments.

Investigation of the Corrosion and Passive Behavior of HP-13Cr Stainless Steel in Formate Annulus Protection Fluid

Investigation of the Corrosion and Passive Behavior of HP-13Cr Stainless Steel in Formate Annulus Protection Fluid

Research on Electrochemical Corrosion and Passive Behavior of CoCrFeNi High-Entropy Alloy Compared with 304 Stainless Steel in a NaCl Environment

Research on Electrochemical Corrosion and Passive Behavior of CoCrFeNi High-Entropy Alloy Compared with 304 Stainless Steel in a NaCl Environment

Behavior-environment interaction aware manufacturing service collaboration optimization

Manufacturing enterprises participate in platform-based collaboration by encapsulating their manufacturing resources/capabilities as manufacturing services (MSs). In platform-based manufacturing service collaboration (MSC), the mutually influential between behaviors of MS providers and the collaborative environment will have an important impact on the MSs supply ability and the MSC scheme planning. Therefore, this paper proposes a behavior-environment interaction aware MSC optimization method. Firstly, the behavior-environment interaction mechanism considering the proactive/ passive behaviors of MS providers (i.e., join/exit platform behavior, accept/reject task behavior, cooperate/non-cooperate behavior) and the collaborative environment is built. Then, the collaborative environment is described by the BBV complex network, taking into account the inherent attributes of the providers and the collaborative relationship based on the priority attachment characteristics. Finally, the behaviour-environment interaction mechanism is combined with the Dueling DQN algorithm to address the MSC optimization problem. The proposed method can effectively solve the MSC optimization problem, ensuring a balanced consideration of the interests of consumers, MS providers and the platform. According to the experiment, the arrival of new MS providers will enhance the global efficiency of the platform. And the higher the willingness of MS providers to participate in MSC, the higher their income and the global efficiency of the platform.

An Investigation about Microstructures, Mechanical Properties and Corrosion Behaviour of the TIG - MIG Hybrid Welded Dissimilar UNS 2205 and is 2062 Steels

The connecting of contrasting metals, namely double stainless steel to steel made of carbon, has taken place. performed using a hybrid welding system. A TIG and MIG welding joining based hybrid joining method was designed. The microstructures of the dissimilar metal joints were studied and the grains are coarser as contrast to the use of a single the welding process process by itself. With the addition of TIG welding to the process of MIG welding, the water-holding capacity of the metal in molten state pool is significantly improved. The nominal corrosion behaviour of the weldments was found better than the single arc welding system alone. The passivation behaviour of the joints was in the similar line to that of double stainless steel base metal. The pitting resistance of the joints in 1 M NaCl solution was inferior to the base metals.

The effect of γ′-martensite on the corrosion resistance of an Fe-Mn-Al-Ni-Cr shape memory alloy in a sodium chloride solution

The martensitic phase transformation in iron-based shape memory alloys has a strong influence on the corrosion properties. To investigate the effect of different amounts of martensite, potentiodynamic polarization measurements were conducted on specimens that were subjected to varying prestrain levels prior to the corrosion experiments. While the passive behavior deteriorates with an increasing martensite amount, the observed corrosion damage changes as well. While an entirely austenitic specimen is characterized by a predominantly surface corrosion with some randomly distributed pitting corrosion, the introduction of the martensitic phase results in micropitting and selective corrosion of the martensite plates.