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1.
Langmuir ; 40(11): 5776-5784, 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38456666

RESUMO

Deposition of molybdenum disulfide (MoS2) 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 MoxSyOz and MoxSyOz/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. Even so, electrodeposited MoxSyOz can achieve low steady-state coefficients of friction (µ ∼ 0.05-0.06) and wear rates (2.6 × 10-7 mm3/(N m)) approaching those of physical vapor deposited coatings (2.3 × 10-7 mm3/(N m)). Additionally, we show that adding dopants such as nickel increased the wear rate (7.5 × 10-7 mm3/(N m)) and initial coefficient of friction (µi = 0.23) due to compositional modifications such as dramatic sub-stoichiometry (S/Mo ∼ 1) and expression of a NiOx surface layer, although doping did reduce the degree of cracking upon drying.

2.
J Adolesc ; 96(2): 322-336, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38010232

RESUMO

INTRODUCTION: Adolescents are experiencing high rates of depressive symptoms, with negative consequences to their long-term health. Group-based, mindful self-compassion programs show promise in mitigating the development of more significant depression in at-risk adolescents. However, the lack of well-designed, active control conditions has limited the ability to examine the efficacy of such interventions. METHODS: Fifty-nine adolescents (Mage = 15.81, 70% female) with subsyndromal depressive symptoms from the Southeastern US were randomized to group-based Mindful Self-Compassion for Teens (N = 30) or a newly developed active control Healthy Lifestyles group (N = 29) during 2018 and 2019. Participants attended 8 weekly "main" sessions followed by 6 monthly continuation sessions. The feasibility and acceptability of participation in both groups were measured using attrition, attendance, credibility, and satisfaction data. Depression scores were collected weekly, and self-compassion scores were collected five times across 36 weeks. RESULTS: Both groups were equally feasible and acceptable during the 8-week program period; however, monthly continuation sessions were poorly attended in both groups. The risk of developing clinically significant depression was 2.6 times higher in the control group compared with the self-compassion group (p = .037) across 36 weeks. Depression significantly decreased in the self-compassion group, while it significantly increased in the control group. Both groups increased significantly in reports of self-compassion. These findings are on par with results noting the efficacy of cognitive-based interventions for high-risk adolescents; follow-up studies with larger sample sizes should be conducted to confirm these findings. CONCLUSIONS: Initial examination suggests Mindful Self-Compassion for Teens programming is feasible, acceptable, and efficacious in preventing the development of clinically significant depression in adolescents with subsyndromal depression. Future studies may benefit from refinements to the self-compassion measurement and/or the attention control condition; moreover, larger sample sizes are needed to confirm results.


Assuntos
Depressão , Atenção Plena , Humanos , Adolescente , Feminino , Masculino , Depressão/terapia , Autocompaixão , Estudos de Viabilidade , Atenção Plena/métodos , Seguimentos
3.
J Clin Child Adolesc Psychol ; 50(4): 486-497, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-32844687

RESUMO

Objective: 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.Method: We conducted a systematic search in PsycInfo and PubMed. We also reviewed references of previous reviews and searched for moderator analyses conducted secondary to published efficacy studies.Results: We review 27 studies that address the following categories of moderators: demographics, severity indices, comorbidity, contextual factors, history of abuse or trauma, and cognition and coping. We found limited evidence that demographic, contextual, or cognitive variables consistently moderated treatment for adolescent depression. There was some indication of moderation by race/ethnicity, presence of some comorbid disorders, greater depression severity, and a history of trauma.Conclusion: Our review found inconsistent findings across studies, likely due to the strong impact of predictors relative to moderators and limited statistical power. More research using innovative statistical approaches is necessary before treatment tailoring can be an empirically-based process.


Assuntos
Depressão/terapia , Adolescente , Comorbidade , Depressão/complicações , Depressão/psicologia , Humanos , Resultado do Tratamento
4.
Depress Anxiety ; 35(12): 1137-1144, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30103266

RESUMO

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.S. military. Demographic and military-specific factors were assessed using administrative personnel records and survey data. RESULTS: Of the 9,038 spouses, 4.9% had a probable diagnosis of MDD. In unadjusted models, spouses of service members who deployed and experiencecd combat-related events, were enlisted, had a probable posttraumatic stress disorder (PTSD) diagnosis, or screened positive for alcohol misuse were more likely to screen positive for MDD. In adjusted models, only spouses married to enlisted service members or those with PTSD had increased risk for MDD. Other demographic and military-related factors associated with MDD in spouses included less educational attainment, unemployment, having four or more children, and having prior military service (although not currently serving in the military) in the adjusted models. CONCLUSIONS: Findings characterize demographic, military, and service member psychological health factors that are associated with depression among military spouses. These findings imply that deployment alone may not negatively affect military spouses, but rather it may be the mental health impact on the service member, especially PTSD that increases the odds for MDD among military spouses.


Assuntos
Transtorno Depressivo Maior/epidemiologia , Militares/estatística & dados numéricos , Cônjuges/estatística & dados numéricos , Transtornos de Estresse Pós-Traumáticos/epidemiologia , Adulto , Feminino , Humanos , Masculino , Estados Unidos/epidemiologia , Adulto Jovem
5.
J Clin Child Adolesc Psychol ; 44(4): 551-8, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-24661263

RESUMO

Major depressive disorder (MDD) is a common disorder among adolescents. The Treatment for Adolescents with Depression Study (TADS) was a randomized controlled trial to examine the efficacy of fluoxetine and cognitive-behavioral therapy (CBT), separately and together, compared with placebo, in adolescents 12 to 17 years of age. The Survey of Outcomes Following Treatment for Adolescent Depression (SOFTAD) was designed as a naturalistic follow-up of participants in TADS. The aims of the current analyses are to describe mental health service use during the SOFTAD period. There were 196 adolescents recruited from 12 TADS sites. The Schedule for Affective Disorders and Schizophrenia for School-Age-Children-Present and Lifetime Version was used for clinical diagnoses. Participants completed a psychiatric treatment log and the Child and Adolescent Services Assessment to assess service use. 58% received psychotherapy or nonstimulant psychotropic medication during SOFTAD. Youth with recurrent MDD had higher rates of treatment compared to youth without recurrent MDD (71% vs. 45%). However, nearly one third of the adolescents in the study did not receive treatment for a recurrent episode of depression. Service use differed by gender for those with recurrent MDD, with female participants (79%) receiving treatment at higher rates than male participants (55%), although there was no significant difference in depression severity between genders. Younger participants with recurrent MDD had higher odds of receiving psychotherapy. Use of psychotherapy and psychotropics following recurrence of depression appears to be influenced by age and gender. Even when youth respond well to treatment, a sizeable percentage are likely to experience a subsequent episode that may go untreated.


Assuntos
Terapia Cognitivo-Comportamental , Transtorno Depressivo Maior/psicologia , Transtorno Depressivo Maior/terapia , Fluoxetina/uso terapêutico , Serviços de Saúde Mental/estatística & dados numéricos , Adolescente , Criança , Terapia Cognitivo-Comportamental/tendências , Terapia Combinada/estatística & dados numéricos , Terapia Combinada/tendências , Transtorno Depressivo Maior/diagnóstico , Feminino , Humanos , Masculino , Inquéritos e Questionários , Resultado do Tratamento
6.
Adm Policy Ment Health ; 42(3): 363-72, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25047869

RESUMO

The current study presents the implementation of a set of school based interventions in a greater New Orleans school district one year following Hurricane Katrina. The interventions included adaptation and implementation of evidence based treatments in a crisis situation with at-risk youth which involved training and clinical challenges. 386 students found to have significant depressive and/or disruptive disorder symptoms received treatment from the School Therapeutic Enhancement Program (STEP). Further, a district-wide mental health needs assessment of middle and high school students (N = 11,861) screened for behavioral and emotional difficulties at the beginning and end of the school year provided a benchmark for community youth's emotional and behavioral distress. High-need intervention students demonstrated clinically significant lower levels of emotional and behavioral problems, depression and inattention in comparison to pre-treatment levels as indicated by multiple informants (i.e., self, parent, teacher). Self-reported distress levels were also lower than screening group students at post-test. These findings support the efficacy of a school-based intervention for youth struggling with the aftereffects of a highly disruptive natural disaster. Implications for utilizing a flexible adaptation of an evidence-based training model involving coaching and consultation are discussed.


Assuntos
Transtornos de Deficit da Atenção e do Comportamento Disruptivo/terapia , Serviços Comunitários de Saúde Mental/organização & administração , Tempestades Ciclônicas , Transtorno Depressivo/terapia , Desastres , Serviços de Saúde Escolar/organização & administração , Adolescente , Criança , Feminino , Humanos , Masculino , Nova Orleans
7.
J Clin Child Adolesc Psychol ; 43(3): 510-26, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24730421

RESUMO

Research over the past 3 decades has shown that psychotherapy can successfully address adolescent depression. Cognitive behavioral models have been most extensively and rigorously tested, with evidence also supporting interpersonal psychotherapy and attachment-based family therapy. However, the vast majority of studies have focused on short-term treatment of depressive episodes, even as evidence accumulates that depression is frequently a recurring condition extending into adulthood. Moreover, treatment studies indicate that better longer term outcomes are attained by adolescents who respond earlier and more completely to intervention. Given what has been learned to date about adolescent depression treatment, future psychotherapy research should adopt a longer term perspective and focus on the following key challenges: (a) preventing relapse and recurrent episodes, while improving speed and thoroughness of initial treatment response; (b) identifying the necessary treatment components and learning processes that lead to successful and enduring recovery from depression; (c) determining whether-and, if so, how-to address comorbid disorders within depression treatment; (d) addressing the dilemma of simplicity versus complexity in treatment models. Given the relatively small number of evidence-based treatment models, newer approaches warrant investigation. These should be tested against existing models and also compared to medication and combined (psychotherapy plus medication) treatment. Advances in technology now enable investigators to improve dissemination, to conduct experimental psychotherapeutics and to expand application of Internet-based interventions to the goals of relapse and recurrence prevention.


Assuntos
Depressão/terapia , Psicoterapia/métodos , Adolescente , Depressão/prevenção & controle , Depressão/psicologia , Transtorno Depressivo/tratamento farmacológico , Transtorno Depressivo/prevenção & controle , Feminino , Humanos , Masculino , Avaliação de Processos e Resultados em Cuidados de Saúde , Relações Pais-Filho , Psicoterapia/tendências , Pesquisa , Prevenção Secundária , Fatores de Tempo
8.
Subst Use Misuse ; 49(3): 234-42, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23965039

RESUMO

This study examined the relative influence of peer socialization and selection on alcohol and marijuana use among 106 adolescents who received a brief intervention. Adolescents were recruited between 2003 and 2007 and followed for 12 months as part of a SAMHSA-funded study. Cross-lagged panel models using four assessment points examined the longitudinal relationship between adolescent substance use and peer substance involvement separately for alcohol and marijuana. Consistent with community studies, there was evidence of both peer socialization and peer selection for alcohol use, and only evidence of peer selection for marijuana use. Implications for research and intervention are discussed.


Assuntos
Comportamento do Adolescente/psicologia , Alcoolismo/psicologia , Alcoolismo/terapia , Abuso de Maconha/psicologia , Abuso de Maconha/terapia , Grupo Associado , Identificação Social , Socialização , Adolescente , Terapia Cognitivo-Comportamental , Humanos , Masculino , Psicoterapia Breve , Adulto Jovem
9.
Subst Abus ; 35(4): 364-75, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25157785

RESUMO

BACKGROUND: Substance use disorders (SUDs) are among the most common psychiatric diagnoses in adolescents. Some research suggests that comorbid depression in adolescents with SUD is associated with increased likelihood of alcohol dependence, poorer social competence, and greater risk for suicide attempts. However, little is known about how depression influences adolescent substance abuse treatment retention and outcomes. METHODS: This review aimed to summarize the effects of comorbid depression on treatment retention and outcomes across 13 adolescent SUD treatment studies. RESULTS: RESULTS indicated that depression has a mixed relationship with treatment retention and outcomes, exerting a negative, positive, or nonsignificant effect depending on aspects of the study. CONCLUSIONS: More research needs to be done, particularly addressing the potential mediators and moderators of the relationship between depression and SUD outcomes. Importantly, recognizing that the studies varied widely in hypotheses and research methods, the field needs to develop more standardized methods to allow for a clearer understanding of the role of comorbid depression.


Assuntos
Comportamento do Adolescente/psicologia , Depressão/epidemiologia , Transtornos Relacionados ao Uso de Substâncias/epidemiologia , Transtornos Relacionados ao Uso de Substâncias/terapia , Adolescente , Comorbidade , Depressão/psicologia , Humanos , Aceitação pelo Paciente de Cuidados de Saúde/psicologia , Transtornos Relacionados ao Uso de Substâncias/psicologia , Resultado do Tratamento
10.
J Cogn Psychother ; 28(1): 3-19, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24944436

RESUMO

Among adolescents there is evidence that cognitive change partially mediates the effect of cognitive behavioral therapy (CBT) on depression outcome. However, prior studies have been limited by small samples, narrow measures of cognition, and failure to compare cognitive change following CBT to cognitive change following antidepressant medication. This study examined whether change in four cognitive constructs (cognitive distortions, cognitive avoidance, positive outlook, and solution-focused thinking) mediated change in depression severity in a sample of 291 adolescents who participated in the Treatment for Adolescents with Depression Study (TADS). TADS assessed the effects of CBT, fluoxetine, and their combination on depression severity. All three treatments were associated with change in the cognitive constructs and combination treatment produced the greatest change. Furthermore, change in the cognitive constructs partially mediated change in depression severity within all three treatments. Results implicated positive outlook as the construct most associated with change in depression severity over 36 weeks.

11.
RSC Adv ; 14(7): 4717-4729, 2024 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-38318617

RESUMO

Molybdenum disulfide (MoS2) 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 MoS2 surfaces and edges with different concentrations of defects under realistic atmospheric conditions (i.e. various temperatures and humidity levels). We find that the amount of water adsorbed depends strongly on the number of defects. Simulations indicate that defect sites are generally saturated with water even at low ppm levels of humidity. Water binds strongly to S vacancies on interlamellar surfaces, but generally only one water molecule can fit on each of these sites. Defects on surfaces or edges of lamellae also strongly attract water molecules that then nucleate small clusters of water bonded via hydrogen bonding. We demonstrate that water preferentially binds to surface defects, but once those are saturated at a critical humidity level of about 500-1000 ppm water, water binds to edge sites where it negatively impacts the tribological performance of MoS2.

12.
Carcinogenesis ; 34(4): 799-802, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23276795

RESUMO

Trichloroethylene (TCE) has been associated with a variety of immunotoxic effects and may be associated with an increased risk of non-Hodgkin lymphoma (NHL). Altered serum immunoglobulin (Ig) levels have been reported in NHL patients and in animals exposed to TCE. Recently, we reported that occupational exposure to TCE is associated with immunosuppressive effects and immune dysfunction, including suppression of B-cell counts and activation, even at relatively low levels. We hypothesized that TCE exposure would also affect Ig levels in humans. We measured serum levels of IgG, IgM and IgE, by enzyme-linked immunosorbent assay, in TCE-exposed workers (n = 80) and unexposed controls (n = 45), matched by age and gender, in a cross-sectional, molecular epidemiology study of occupational exposure to TCE in Guangdong, China. Exposed workers had about a 17.5% decline in serum levels of IgG compared with unexposed controls (P = 0.0002). Similarly, serum levels of IgM were reduced by about 38% in workers exposed to TCE compared with unexposed controls (P < 0.0001). Serum levels of both IgG and IgM were significantly decreased in workers exposed to TCE levels below 12 p.p.m., the median exposure level. Adjustment for B-cell counts had minimal impact on our findings. IgE levels were not significantly different between exposed and control subjects. These results provide further evidence that TCE is immunotoxic at relatively low exposure levels and provide additional biologic plausibility for the reported association of TCE with NHL.


Assuntos
Imunoglobulina E/sangue , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Exposição Ocupacional/efeitos adversos , Tricloroetileno/toxicidade , Adulto , Linfócitos B/efeitos dos fármacos , China/epidemiologia , Feminino , Humanos , Contagem de Linfócitos , Linfoma não Hodgkin/sangue , Linfoma não Hodgkin/epidemiologia , Linfoma não Hodgkin/imunologia , Masculino , Epidemiologia Molecular
13.
J Exp Med ; 204(10): 2293-303, 2007 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-17785508

RESUMO

The V(D)J recombinase catalyzes DNA transposition and translocation both in vitro and in vivo. Because lymphoid malignancies contain chromosomal translocations involving antigen receptor and protooncogene loci, it is critical to understand the types of "mistakes" made by the recombinase. Using a newly devised assay, we characterized 48 unique TCRbeta recombination signal sequence (RSS) end insertions in murine thymocyte and splenocyte genomic DNA samples. Nearly half of these events targeted "cryptic" RSS-like elements. In no instance did we detect target-site duplications, which is a hallmark of recombinase-mediated transposition in vitro. Rather, these insertions were most likely caused by either V(D)J recombination between a bona fide RSS and a cryptic RSS or the insertion of signal circles into chromosomal loci via a V(D)J recombination-like mechanism. Although wild-type, p53, p53 x scid, H2Ax, and ATM mutant thymocytes all showed similar levels of RSS end insertions, core-RAG2 mutant thymocytes showed a sevenfold greater frequency of such events. Thus, the noncore domain of RAG2 serves to limit the extent to which the integrity of the genome is threatened by mistargeting of V(D)J recombination.


Assuntos
Diferenciação Celular/imunologia , Cromossomos de Mamíferos/genética , Recombinação Genética/genética , Linfócitos T/imunologia , Linfócitos T/metabolismo , Animais , Sequência de Bases , Linhagem Celular , DNA/genética , Camundongos , Camundongos Knockout , Mutação/genética , Timo/metabolismo
14.
Behav Res Ther ; 171: 104429, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37992481

RESUMO

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). We then used ecological momentary assessment (EMA) to evaluate concurrent fluctuations in daily anxiety and reassurance seeking across 14 consecutive days (Aim 3). Hierarchical multi-level models for intensive longitudinal data were used to evaluate the relationship between state anxiety and daily reassurance seeking. RESULTS: In baseline analyses, trait anxiety and intolerance of uncertainty were significantly associated with greater trait reassurance seeking, controlling for depression. Analyses of the EMA data showed that daily reassurance seeking behaviors fluctuated concurrently with daily anxiety during the 14 days, while controlling for trait anxiety and depression. CONCLUSION: Given evidence of concurrent fluctuations between state anxiety and reassurance seeking, the behavior should be considered as a potential target in treatment for anxiety disorders.


Assuntos
Transtornos de Ansiedade , Avaliação Momentânea Ecológica , Adulto Jovem , Humanos , Estudos Transversais , Transtornos de Ansiedade/terapia , Ansiedade/terapia , Relações Interpessoais
15.
ACS Appl Nano Mater ; 6(2): 1153-1160, 2023 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-36743857

RESUMO

For decades, density has been attributed as a critical aspect of the structure of sputter-deposited nanocrystalline molybdenum disulfide (MoS2) 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 MoS2 coatings. Aging and oxidation are primary considerations for the use of MoS2 coatings in aerospace applications as they inevitably experience prolonged storage in water and oxygen-rich environments prior to use. Oxidation that is either limited to the first few nanometers or through the bulk of the coating can result in seizure due to high initial coefficients of friction or component failure from excessive wear. High-sensitivity low-energy ion spectroscopy (HS-LEIS) and Rutherford backscattering spectrometry (RBS) are both used to understand the extent of oxidation throughout the first ∼10 nanometers of the surface of pure sputtered nanocrystalline MoS2 coatings after high-temperature aging and how it is impacted by the density of coatings as measured by RBS. Results show that low-density coatings (ρ = 3.55 g/cm3) exhibit a more columnar microstructure and voiding, which act as pathways for oxidative species to penetrate and interact with edge sites, causing severe surface and subsurface oxidation. Furthermore, HS-LEIS of surfaces sheared prior to oxidation reveals that the oxidation resistance of low-density MoS2 coatings can be significantly improved by shear-induced reorientation of the surface microstructure to a basal orientation and elimination of pathways for oxygen into the bulk through compaction of surface and subsurface voids.

16.
ACS Appl Mater Interfaces ; 15(30): 37047-37058, 2023 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-37486090

RESUMO

Molybdenum disulfide (MoS2) coatings have attracted widespread industrial interest owing to their excellent lubricating properties under vacuum and inert conditions. Unfortunately, the increase in MoS2 interfacial shear strength following prolonged exposure to ambient conditions (a process referred to as "aging") has resulted in reliability issues when MoS2 is employed as solid lubricant. While aging of MoS2 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 MoS2 is still elusive. Additionally, remarkably little is known about the effect of thermally- and tribologically-induced microstructural variations in MoS2 on the aging processes occurring in the near-surface region of the coating. Here, we employed three analytical techniques, namely, X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), and grazing-incidence X-ray diffraction (GIXRD), to gain insights into the aging phenomena occurring in sputtered MoS2 coatings before and after tribological testing, while also evaluating the impact of thermally-induced variations in the coating structure on aging. The outcomes of XPS analyses provide evidence that a substantial surface oxidation of MoS2 only takes place under humid conditions. Furthermore, the correlation of XPS, ToF-SIMS, and GIXRD results allowed for the development of a qualitative model for the impact of shear-induced microstructural variations in MoS2 on the transport of water in the near-surface region of this material and on the extent of surface oxidation. These results add significantly to our understanding of the aging mechanisms of MoS2 coatings used in tribological applications and their dependence on environmental conditions.

17.
ACS Appl Mater Interfaces ; 14(11): 13914-13924, 2022 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-35272457

RESUMO

This work investigates the role of water and oxygen on the shear-induced structural modifications of molybdenum disulfide (MoS2) 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., dry N2) or humid lab air forms basally oriented (002) running films of varying thickness and structure. Tribological testing of the basally oriented surfaces created in dry N2 and air showed lower initial friction than a coating with an amorphous or nanocrystalline microstructure. Aging of coatings with basally oriented surfaces was performed by heating samples at 250 °C for 24 h. Post aging tribological testing of the as-deposited coating showed increased initial friction and a longer transition from higher friction to lower friction (i.e., run-in) due to oxidation of the surface. Tribological testing of raster patches formed in dry N2 and air both showed an improved resistance to oxidation and reduced initial friction after aging. The results from this study have implications for the use of MoS2-coated mechanisms in aerospace and space applications and highlight the importance of preflight testing. Preflight cycling of components in inert or air environments provides an oriented surface microstructure with fewer interaction sites for oxidation and a lower shear strength, reducing the initial friction coefficient and oxidation due to aging or exposure to reactive species (i.e., atomic oxygen).

18.
J Am Acad Child Adolesc Psychiatry ; 61(4): 508-519, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-34371102

RESUMO

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 [1.8]) with alcohol or cannabis use and depressive symptoms received up to 12 sessions of CBT for substance use over 14 weeks. Assessments were at baseline and weeks 4, 9, and 14. The Children's Depression Rating Scale-Revised was the primary depression measure, with a reduction of 50% or more on this scale at week 4 defining EDR. The primary substance use outcomes of alcohol use, heavy alcohol use, and cannabis use frequency were assessed via interview report on the Alcohol Consumption Questionnaire and the Drug Checklist. Urinalysis provided a secondary measure of cannabis use. Non-EDR adolescents were randomly assigned to supplemental CBT-D or enhanced treatment as usual (ETAU). RESULTS: Thirty-five adolescents (37%; 95% CI, 27%-47%) demonstrated EDR. Fewer days of cannabis use (odds ratio 0.977; 95% CI, 0.961-0.992) and absence of conduct disorder (odds ratio 0.149; 95% CI, 0.031-0.716) predicted EDR. Frequency of drinking (F1,82 = 11.09, η2 = 0.119, p = .001), heavy drinking (F1,82 = 19.91, η2 = 0.195, p < .0001), and cannabis use (F1,220 = 35.01, η2 = 0.137, p < .001) decreased over time for EDR, CBT-D, and ETAU adolescents, with EDR adolescents evidencing earlier lower cannabis use (F2,220 = 4.16, η2 = 0.036, p = .0169). Negative (clean) urine screens increased over time (F1,219 = 5.10, η2 = 0.023, p = .0249). Comparison of CBT-D and ETAU indicated that depression significantly decreased over time in both groups (F1,48 = 64.20, η2 = 0.572, p < .001), with no advantage for CBT-D. CONCLUSION: Approximately one-third of adolescents with substance use and depression attain EDR during substance use treatment. Less frequent cannabis use facilitates depression response. The relatively small sample may have precluded identification of additional EDR predictors. CLINICAL TRIAL REGISTRATION INFORMATION: Treatment for Teens With Alcohol Abuse and Depression; https://clinicaltrials.gov/; NCT02227589.


Assuntos
Cannabis , Terapia Cognitivo-Comportamental , Transtornos Relacionados ao Uso de Substâncias , Adolescente , Adulto , Criança , Depressão/terapia , Humanos , Resultado do Tratamento , Adulto Jovem
20.
Psychol Serv ; 18(2): 275-284, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-31750696

RESUMO

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. We investigated frequency and correlates of recurrent MDD among female veterans and their male counterparts. From a postdeployment research registry of 3,247 participants (660 women and 2,587 men), we selected those with a current episode of MDD (141 women and 462 men). For each sex, we compared those diagnosed with recurrent MDD with those experiencing a single episode on demographics, comorbid diagnoses, family history of mental illness, traumatic experiences, combat exposure, and social support. In contrast to findings in most civilian samples, recurrent MDD was significantly more frequent in female (70.2%) than in male (45.2%) depressed veterans, χ²(1) = 26.96, p < .001. In multivariable analyses, recurrence among women was associated with greater experiences of childhood abuse and more trauma during military service and with lower rates of posttraumatic stress disorder. Among men, recurrence was associated with older age, family history of psychiatric hospitalization, more postmilitary trauma, and lifetime anxiety disorder and with lower likelihood of war zone deployment. Trauma was associated with recurrence in both sexes, but the features of traumatic events differed in women and men. (PsycInfo Database Record (c) 2021 APA, all rights reserved).


Assuntos
Transtorno Depressivo Maior , Militares , Transtornos de Estresse Pós-Traumáticos , Veteranos , Idoso , Criança , Depressão , Transtorno Depressivo Maior/epidemiologia , Feminino , Humanos , Masculino , Caracteres Sexuais , Transtornos de Estresse Pós-Traumáticos/epidemiologia
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