Microstructural Assessment of Molybdenum Disulfide Coatings Using Nanoindentation Hardness.

MoS coatings are used extensively in aerospace and defense applications due to their ultralow friction and high wear resistance. Burnished and resin-bonded MoS coatings are commonly used in these applications due to simplicity in deposition and history of use, despite issues with consistency in coating properties and performance. Physical vapor deposition (PVD) of MoS thin films has emerged as a process alternative in the past 50 years, promising far greater control over film structure and composition but at a greater cost.

Electrodeposited MoSO/Ni Tribological Coatings.

Deposition of molybdenum disulfide (MoS) coatings using physical vapor deposition (PVD) and mechanical burnishing has been widely assessed for solid lubricants in space applications but still suffers from line-of-sight constraints on complex geometries. Here, we highlight one of the first demonstrations of electrodeposited MoSO and MoSO/Ni thin-film coatings from aqueous solutions of ammonium tetrathiomolybdate for solid lubricant applications and their remarkable ability to provide low coefficients of friction and high wear resistance. Characterization of the coating morphology shows amorphous microstructures with a high oxygen content and cracking upon drying.

Water adsorption on MoS under realistic atmosphere conditions and impacts on tribology.

Molybdenum disulfide (MoS) is a 2D material widely used as a dry lubricant. However, exposure to water and oxygen is known to reduce its effectiveness, and therefore an understanding of the uptake of water is important information for mitigating these effects. Here we use grand canonical Monte Carlo simulations to rigorously study water adsorption on MoS surfaces and edges with different concentrations of defects under realistic atmospheric conditions ( various temperatures and humidity levels).

Is everything really okay?: Using ecological momentary assessment to evaluate daily co-fluctuations in anxiety and reassurance seeking.

Objective: Reassurance seeking, a behavior prominent in anxiety disorders and depression, is associated with poorer quality of interpersonal relationships and acts as a mechanism of stress generation. However, little research has elucidated momentary associations between state anxiety and reassurance seeking behaviors.

Method: In a sample of 104 university-affiliated young adults, we sought to replicate cross-sectional associations of reassurance seeking with trait anxiety (Aim 1) and intolerance of uncertainty (Aim 2).

Spectroscopic Evaluation of Surface Chemical Processes Occurring in MoS upon Aging.

Molybdenum disulfide (MoS) coatings have attracted widespread industrial interest owing to their excellent lubricating properties under vacuum and inert conditions. Unfortunately, the increase in MoS interfacial shear strength following prolonged exposure to ambient conditions (a process referred to as "aging") has resulted in reliability issues when MoS is employed as solid lubricant. While aging of MoS is generally attributed to physical and chemical changes caused by adsorbed water and/or oxygen, a mechanistic understanding of the relative role of these two gaseous species in the evolution of the surface chemistry of MoS is still elusive.

High-Sensitivity Low-Energy Ion Spectroscopy with Sub-Nanometer Depth Resolution Reveals Oxidation Resistance of MoS Increases with Film Density and Shear-Induced Nanostructural Modifications of the Surface.

For decades, density has been attributed as a critical aspect of the structure of sputter-deposited nanocrystalline molybdenum disulfide (MoS) coatings impacting oxidation resistance and wear resistance. Despite its importance, there are few examples in the literature that explicitly investigate the relationship between the density and oxidation behaviors of MoS coatings. Aging and oxidation are primary considerations for the use of MoS coatings in aerospace applications as they inevitably experience prolonged storage in water and oxygen-rich environments prior to use.

Role of Environment on the Shear-Induced Structural Evolution of MoS and Impact on Oxidation and Tribological Properties for Space Applications.

This work investigates the role of water and oxygen on the shear-induced structural modifications of molybdenum disulfide (MoS) coatings for space applications and the impact on friction due to oxidation from aging. We observed from transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) that sliding in both an inert environment (i.e.

Hopelessness and depressive symptoms in children and adolescents: An integrative data analysis.

Although hopelessness has been linked to depression for centuries, the diagnostic criteria for depression are inconsistent with regard to the status of hopelessness. Most research on hopelessness and depression has focused on adults. The current study examined this relation in children and adolescents.

Adaptive Treatment for Youth With Substance Use and Depression: Early Depression Response and Short-term Outcomes.

Objective: To investigate prevalence and predictors of early depression response (EDR) in adolescents with substance use and depression receiving cognitive-behavioral therapy (CBT) for substance use and to test the efficacy of supplemental CBT targeting depression (CBT-D) for non-EDR adolescents in an adaptive treatment approach.

Method: At 2 sites, 95 youths (ages 14-21, mean [SD] = 17.4 [1.

Formation of Coherent 1H-1T Heterostructures in Single-Layer MoS on Au(111).

Heterojunctions of semiconductors and metals are the fundamental building blocks of modern electronics. Coherent heterostructures between dissimilar materials can be achieved by composition, doping, or heteroepitaxy of chemically different elements. Here, we report the formation of coherent single-layer 1H-1T MoS heterostructures by mechanical exfoliation on Au(111), which are chemically homogeneous with matched lattices but show electronically distinct semiconducting (1H phase) and metallic (1T phase) character, with the formation of these heterojunctions attributed to a combination of lattice strain and charge transfer.

Moderators of Treatment for Adolescent Depression.

: This brief report reviews the literature on moderators of treatment for adolescent depression. Treatment moderators can help to guide the process of personalizing intervention to individual patient characteristics.: We conducted a systematic search in PsycInfo and PubMed.

Temporal dynamics of the relationship between change in depressive symptoms and cannabis use in adolescents receiving psychosocial treatment for cannabis use disorder.

Aims: Cannabis use disorder (CUD) and depression frequently co-occur in youth. How depressive symptoms change over the course of CUD treatment and how they impact substance use treatment outcomes is unknown. In the current study, we examine the temporal relationships between cannabis use and depression in adolescents receiving evidence-based treatments for CUD as part of a multisite clinical trial.

Evidence of Inverse Hall-Petch Behavior and Low Friction and Wear in High Entropy Alloys.

We present evidence of inverse Hall-Petch behavior for a single-phase high entropy alloy (CoCrFeMnNi) in ultra-high vacuum and show that it is associated with low friction coefficients (~0.3). Grain size measurements by STEM validate a recently proposed dynamic amorphization model that accurately predicts grain size-dependent shear strength in the inverse Hall-Petch regime.

Sex differences in predictors of recurrent major depression among current-era military veterans.

Although major depressive disorder (MDD) is a frequent diagnosis among women seeking care in the Veterans Health Administration, little is known about its course. For example, recurrence of MDD and its predictors have been investigated in civilians, but not among female veterans. Because female veterans differ from their civilian counterparts and from male veterans on demographic variables, including race, ethnicity, marital status, and educational level, it is important to identify factors affecting MDD course within this population.

Depression among military spouses: Demographic, military, and service member psychological health risk factors.

Background: More than a decade of war has strained service members and their families and the psychological health of military spouses is a concern. This study uses data from the largest study of military families in the United States to examine the demographic, military-specific, and service member mental health correlates of probable diagnosis of major depressive disorder (MDD) among military spouses.

Methods: Data were from service member-spouse dyads from all branches of the U.

Achieving Ultralow Wear with Stable Nanocrystalline Metals.

Recent work suggests that thermally stable nanocrystallinity in metals is achievable in several binary alloys by modifying grain boundary energies via solute segregation. The remarkable thermal stability of these alloys has been demonstrated in recent reports, with many alloys exhibiting negligible grain growth during prolonged exposure to near-melting temperatures. Pt-Au, a proposed stable alloy consisting of two noble metals, is shown to exhibit extraordinary resistance to wear.

Impact of Microstructure on MoS Oxidation and Friction.

This work demonstrates the role of microstructure in the friction and oxidation behavior of the lamellar solid lubricant molybdenum disulfide (MoS). We report on systematic investigations of oxidation and friction for two MoS films with distinctively different microstructures-amorphous and planar/highly-ordered-before and after exposure to atomic oxygen (AO) and high-temperature (250 °C) molecular oxygen. A combination of experimental tribology, molecular dynamics simulations, X-ray photoelectron spectroscopy (XPS), and high-sensitivity low-energy ion scattering (HS-LEIS) was used to reveal new insights about the links between structure and properties of these widely utilized low-friction materials.

Paternal history of mental illness associated with posttraumatic stress disorder among veterans.

This study examined the association between parent and family reported history of non-PTSD mental illness (MI), PTSD specifically, and substance use problems, and participant clinical diagnosis of PTSD. Participants were drawn from the US Department of Veterans Affairs Mid-Atlantic Mental Illness Research, Education and Clinical Center (MIRECC) Post-Deployment Mental Health (PDMH) study (n = 3191), an ongoing multi-site cohort study of US Afghanistan and Iraq conflict era veterans. Participants who recalled a father history of PTSD had a 26-percentage point higher likelihood of meeting criteria for PTSD; while participants reporting any family history of PTSD had a 15-percentage point higher probability of endorsing symptoms consistent with PTSD.

Alcohol expectancies and drinking behaviors among college students with disordered eating.

Objective: The authors investigated binge drinking, alcohol expectancies, and risky and protective drinking behaviors in relation to disordered eating behaviors in male and female college students.

Participants: The full sample consisted of 7,720 undergraduate students, 18 to 22 years of age. Drinking behaviors were analyzed in 4,592 recent drinkers.

Trajectories of Functioning Into Emerging Adulthood Following Treatment for Adolescent Depression.

Purpose: It is well established that empirically supported treatments reduce depressive symptoms for most adolescents; however, it is not yet known whether these interventions lead to sustained improvements in global functioning. The goal of this study is to assess the clinical characteristics and trajectories of long-term psychosocial functioning among emerging adults who have experienced adolescent-onset major depressive disorder.

Methods: Global functioning was assessed using the Clinical Global Assessment Scale for children (participants ≤18 years), the Global Assessment of Functioning (participants ≥ 19 years) and the Health of the Nation Outcome Scales for Adolescents among 196 adolescents who elected to complete 3.

Drug use and childhood-, military- and post-military trauma exposure among women and men veterans.

Background: The current study was undertaken to examine whether posttraumatic stress symptoms (PTSS) and depressive symptoms mediated the association between trauma exposure (combat-related trauma and non-combat traumas occurring before, during, and after military service), and drug abuse symptoms use among male and female veterans.

Methods: Participants were 2304 (1851 male, 453 female) veterans who took part in a multi-site research study conducted through the Department of Veterans Affairs Mid-Atlantic Mental Illness Research, Education and Clinical Center (VISN 6 MIRECC). Path analytic models were used to determine the association between problematic past-year drug use and combat-related and non-combat trauma experienced before, during, or after the military and whether current post-traumatic stress symptoms or depressive symptoms mediated these associations.