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1.
Acta Mater ; 2152021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37051579

RESUMO

The microstructure of a hot-work tool steel additively manufactured using laser powder-bed fusion (L-PBF), and its response to post heat treatment, is studied in detail by microstructure characterization and computational thermodynamics and kinetics. The high solidification and cooling rates during the L-PBF process lead to suppression of δ-ferrite and instead solidification of an austenite phase directly containing a cellular substructure where the alloying elements have segregated to the inter-cellular regions and where solidification carbides have formed in the cell junctions. The austenite is then partly decomposed into martensite at lower temperatures. The micro-segregation can be predicted by reducing the complex solidification behavior to a diffusion problem in one dimension enabling detailed comparisons with the measured segregation profiles quantified at a nanometer scale. Martensite start temperature (Ms) calculations along the spatially varying composition show that the Ms temperature decreases in the inter-cellular regions where austenite is observed. The network of austenite in the as-built microstructure can be understood from the combined influence of the composition dependence of the Ms temperature in relation to the build plate temperature and the mechanical stabilization of the small-sized austenite regions. This work demonstrates the power of computational tools based on computational thermodynamics and kinetics for designing tool steels for additive manufacturing by predictions of the steel's response to the L-PBF process and post heat treatments.

2.
J Affect Disord ; 264: 310-317, 2020 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-32056766

RESUMO

BACKGROUND: Hoarding disorder (HD) is a highly debilitating psychiatric disorder that affects 2-6% of adults. Neuropsychological deficits in visual memory, detection, and categorization have been reported in HD. To date, no study has examined the relationship between neurocognitive functioning and treatment for HD. We aim to determine the association between neurocognitive functioning and treatment outcomes, as well as the impact of HD-specific treatment on cognitive functioning. METHODS: 323 individuals with HD were randomized to 20 weeks of peer- or clinician-led group behavioral treatment. 242 participants completed pre- and post-treatment neuropsychological testing covering eight neurocognitive domains. Rates of cognitive impairment (CI) were assessed for each neurocognitive domain. The association of baseline neurocognitive function on treatment response was examined using multiple regression. MANOVA and post-hoc tests were used to determine neurocognitive performance change pre- to post treatment. RESULTS: Sixty-seven percent of participants had CI on ≥1 cognitive domain. There was no significant effect of pre-treatment neurocognitive functioning on treatment outcome. Post-treatment improvements were observed in visual memory, visual detection, decision making, information processing speed, visuospatial processing, attention/working memory (p≤.001). Declines in performance were found in visual reaction time and categorization. LIMITATIONS: This was a non-inferiority trial to examine two treatment types with no normative comparison group. Treatment seeking individuals are more likely to be insightful, motivated, and have other features which limit generalizability. CONCLUSIONS: Patterns of cognitive impairment in HD are similar to previous reports. Pre-treatment neurocognitive functioning did not impact treatment response. Neuropsychological functioning improved across multiple domains following targeted treatment.


Assuntos
Transtorno de Acumulação , Adulto , Atenção , Cognição , Transtorno de Acumulação/terapia , Humanos , Memória , Testes Neuropsicológicos
3.
Br J Clin Psychol ; 59(1): 1-21, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31271462

RESUMO

OBJECTIVES: Hoarding disorder (HD) was recognized as a psychiatric disorder in 2013. Existing literature suggests room for improvement in its treatment. The current pilot study aimed to provide an initial evaluation on the potential of compassion-focused therapy (CFT) as an intervention for HD, with the primary aim being assessing its feasibility and acceptability, and the secondary being evaluating its effects. DESIGN: Both CFT and a second round of the current standard of treatment and cognitive behavioural therapy (CBT) were investigated in the current study as follow-up treatment options for individuals who had completed CBT but were still significantly symptomatic. METHODS: Forty eligible individuals were enrolled (20 in each treatment). Treatment feasibility and acceptability were assessed by quantitative and qualitative measures. To explore treatment effects, HD symptom severity, HD-related dysfunctions, and their underlying mechanisms were assessed pre-treatment and post-treatment. RESULTS: Retention rates were 72% for CFT and 37% for CBT. All participants and 79% of the participants rated CFT and CBT, respectively, as good or excellent. After receiving CFT as a follow-up treatment, HD symptom severity dropped below the cut-off point for clinically significant HD for 77% of the treatment completers, and 62% achieved clinically significant reduction in symptom severity. In contrast, after completing a second course of CBT, 23% had HD symptom severity dropped below the cut-off threshold, and 29% achieved clinically significant symptom reduction. CONCLUSIONS: The current study showed satisfactory feasibility and acceptability of CFT. Moreover, it also found promising effects of CFT in addressing hoarding-related mechanisms that may not have been sufficiently addressed by CBT. The results suggest promising potential of CFT as a treatment for HD. Further investigation on this intervention is needed. PRACTITIONER POINTS: CFT may be a promising treatment option, particularly for those who do not respond well to CBT. Improving emotion regulation and negative self-perception by applying CFT interventions may help relieve hoarding symptoms. Generalization of the findings should be applied with caution given the small convenience sample of the current study. Statistical comparison on treatment effect measures between CFT and CBT as follow-up treatments was not available due to small sample size. Therefore, the comparative conclusions based on this pilot study should be made with caution.


Assuntos
Terapia Cognitivo-Comportamental/métodos , Empatia/fisiologia , Transtorno de Acumulação/psicologia , Adulto , Idoso , Estudos de Viabilidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto
4.
Contemp Clin Trials Commun ; 12: 169-175, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30480164

RESUMO

This study compares the effectiveness of approaches used to recruit a diverse sample for a randomized clinical trial for Hoarding Disorder (HD) in the San Francisco Bay Area. Of the 632 individuals who inquired about the study, 313 were randomized and 231 completed treatment. Most participants heard about the study via flyering (N = 161), followed by advocacy groups (N = 113), word of mouth (N = 84), health care professionals (N = 78), online (N = 68), and media (N = 11). However, those that heard about the study via advertising methods, such as flyers, were less likely to complete the study, p = .01, while those recruited via advocacy groups were most likely to be randomized, p = .03. No source proved more effective in recruiting underrepresented groups such as men, p = .60; non-whites, p = .49; or Hispanics, p = .97. Advertising recruited the youngest individuals, p < 0.001, and word of mouth was most likely to recruit unemployed, disabled, or retired individuals, p = .01. Thus, results suggest an ongoing multimodal approach is likely to be most effective in both soliciting and retaining a diverse sample. Future studies should compare recruitment methods across greater geographical regions too, as well as in terms of financial and human costs.

5.
BJPsych Open ; 4(4): 285-293, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30083381

RESUMO

BACKGROUND: Treatment for hoarding disorder is typically performed by mental health professionals, potentially limiting access to care in underserved areas. AIMS: We aimed to conduct a non-inferiority trial of group peer-facilitated therapy (G-PFT) and group psychologist-led cognitive-behavioural therapy (G-CBT). METHOD: We randomised 323 adults with hording disorder 15 weeks of G-PFT or 16 weeks of G-CBT and assessed at baseline, post-treatment and longitudinally (≥3 months post-treatment: mean 14.4 months, range 3-25). Predictors of treatment response were examined. RESULTS: G-PFT (effect size 1.20) was as effective as G-CBT (effect size 1.21; between-group difference 1.82 points, t = -1.71, d.f. = 245, P = 0.04). More homework completion and ongoing help from family and friends resulted in lower severity scores at longitudinal follow-up (t = 2.79, d.f. = 175, P = 0.006; t = 2.89, d.f. = 175, P = 0.004). CONCLUSIONS: Peer-led groups were as effective as psychologist-led groups, providing a novel treatment avenue for individuals without access to mental health professionals. DECLARATION OF INTEREST: C.A.M. has received grant funding from the National Institutes of Health (NIH) and travel reimbursement and speakers' honoraria from the Tourette Association of America (TAA), as well as honoraria and travel reimbursement from the NIH for serving as an NIH Study Section reviewer. K.D. receives research support from the NIH and honoraria and travel reimbursement from the NIH for serving as an NIH Study Section reviewer. R.S.M. receives research support from the National Institute of Mental Health, National Institute of Aging, the Hillblom Foundation, Janssen Pharmaceuticals (research grant) and the Alzheimer's Association. R.S.M. has also received travel support from the National Institute of Mental Health for Workshop participation. J.Y.T. receives research support from the NIH, Patient-Centered Outcomes Research Institute and the California Tobacco Related Research Program, and honoraria and travel reimbursement from the NIH for serving as an NIH Study Section reviewer. All other authors report no conflicts of interest.

6.
Eur J Psychotraumatol ; 9(1): 1472988, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29887977

RESUMO

Voluntary recall of trauma is a key element in exposure-based psychotherapies and can trigger spontaneous dissociative responses such as flashbacks, depersonalisation, and derealisation. In order to examine the associations between cardiovascular and psychological responses to voluntary recollection of trauma, individuals with PTSD recalled a traumatic memory. Heart rate and heart rate variability were recorded continuously and the episodes when different forms of dissociation were experienced during the recall were identified. A significant increase in parasympathetic activity was found during trauma recall, with greater parasympathetic dominance being indicative of greater state depersonalisation/derealisation. Whereas overall decreases in heart rate during trauma recall were associated with increased fear and perceived threat, flashbacks were accompanied by short-term increases in heart rate. These findings demonstrate different types of cardiovascular responses associated with different psychological experiences during trauma recall. Future research directions were discussed.


El recuerdo voluntario del trauma es un elemento clave en las psicoterapias basadas en la exposición y puede gatillar respuestas disociativas espontáneas como flashbacks, despersonalización y desrealización. Con el fin de examinar las asociaciones entre las respuestas cardiovascular y psicológica al recuerdo voluntario del trauma, individuos con TEPT evocaron una memoria traumática. Se midió en forma continua su frecuencia cardiaca y la variabilidad de la misma y se identificó los episodios en que experimentaron diferentes formas de disociación durante la evocación. Se encontró un incremento significativo en la actividad parasimpática durante el recuerdo del trauma, siendo una mayor dominancia parasimpática indicadora de un mayor estado de despersonalización/desrealización. Mientras que una disminución general en la frecuencia cardiaca durante el recuerdo del trauma se asoció a un incremento del miedo y percepción de amenaza, los flashbacks estaban acompañados de incrementos breves de la frecuencia cardiaca. Estos hallazgos demuestran que diferentes tipos de respuesta cardiovascular se asocian a diferentes experiencias psicológicas durante el recuerdo del trauma. Se discutieron futuras direcciones para la investigación.

7.
Psychiatry Res ; 267: 30-36, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29883858

RESUMO

Early life adversity, ranging from material deprivation and parental dysfunction to abusive and life-threatening events, has been associated with hoarding symptom severity. Moreover, both victims of early life adversity and individuals with hoarding disorder have been found to have a higher tendency toward detail-oriented visual processing. This study aimed to investigate the role of detail-oriented visual processing in the relationship between early life adversity and hoarding-related dysfunction. Childhood exposure to life adversity, hoarding symptom severity, and emotional attachment to possessions, a hoarding-related dysfunction thought to be most closely related to adversity exposure, were assessed. Detail-oriented visual processing was evaluated using the Central Coherence Index, which was calculated based on the drawing process during the Rey-Osterrieth Complex Figure Test. It was found that detail-oriented visual processing was not significantly associated with hoarding symptom severity, emotional attachment to possessions, or the relationship between early life adversity and hoarding symptom severity. It did, however, act as a significant moderator in the relationship between early life adversity and emotional attachment to possessions. These findings add to the literature by identifying the role of a specific neurocognitive processing style in the mechanism through which early life adversity affects the development of a key hoarding-related dysfunction, elevated emotional attachment to possessions.


Assuntos
Experiências Adversas da Infância/tendências , Transtorno de Acumulação/diagnóstico , Transtorno de Acumulação/psicologia , Percepção Visual/fisiologia , Adulto , Idoso , Criança , Cognição/fisiologia , Emoções/fisiologia , Feminino , Transtorno de Acumulação/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Propriedade/tendências , Adulto Jovem
8.
Psychiatry Res ; 262: 488-493, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-28939393

RESUMO

Pathological hoarding-related beliefs, such as need to control possessions, and inflated sense of responsibility over possessions, have been used to explain the development of symptoms of hoarding disorder (HD). While these beliefs have been the focus of the current standard treatment for HD, it is of significant clinical interest to further examine other constructs that may be linked to, or may underliethese beliefs, as well as the pathology of HD. To this end, the current study aimed to build on existing findings regarding the relationship of compromised self-identity with HD. Specifically, we investigated the relationship between self-criticism, shame, hoarding beliefs, and severity of HD symptoms among 104 treatment-seeking individuals with HD. We found that self-criticism and shame are positively associated with HD symptoms and hoarding related beliefs. Moreover, our data shed light on how these factors are connected by elucidating the indirect effects of self-criticism and shame on HD symptoms, mediated through beliefs about inflated sense of responsibility over possessions. The findings have implications for future research to examine interventions targeting compromised self-identity, including self-criticism and shame, among individuals with HD.


Assuntos
Transtorno de Acumulação/fisiopatologia , Autoavaliação (Psicologia) , Vergonha , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
9.
Biol Psychol ; 103: 135-43, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25150464

RESUMO

Evidence suggests that previous trauma reduces the cortisol response to subsequent stressors. We examined the relation of this response to intrusive memory, and the potential moderating roles of sympathetic reactions. Pre-existing trauma-related factors and the cardiac defense response were assessed before 58 healthy participants viewed a trauma film. Salivary cortisol and alpha-amylase (sAA) were collected pre-, peri- and post-film. Intrusive memories about the film were recorded for a week. Cortisol increased whereas sAA decreased after the film. Those with more recent traumatic experiences and greater subclinical PTSD symptoms had lower cortisol concentration post-film. Lower cortisol levels predicted greater vividness of intrusions. Positive correlations between cortisol and the frequency of intrusion were only present among individuals with more sympathetic activations. These findings suggest the contribution of insufficient cortisol secretion to over-consolidation of traumatic memory, and highlight the variation attributable to individual differences and different memory characteristics.


Assuntos
Hidrocortisona/análise , Memória/fisiologia , Transtornos de Estresse Pós-Traumáticos/fisiopatologia , Sistema Nervoso Simpático/fisiopatologia , Adolescente , Adulto , Feminino , Humanos , Masculino , Saliva/química , alfa-Amilases Salivares/análise , Adulto Jovem
10.
Artigo em Inglês | MEDLINE | ID: mdl-24563730

RESUMO

BACKGROUND: The representation of low- and middle-income countries (LMIC) in traumatic stress research is important to establish a global evidence base, build research capacity, and reduce the burden of unmet mental health needs around the world. Reviews of the traumatic stress literature up to 2002 showed trends toward globalization although LMIC were only marginally represented compared to high-income countries (HIC). OBJECTIVE: To examine the global nature of current traumatic stress research. In particular, we were interested in the extent to which traumatic stress research is: (1) conducted in LMIC, (2) conducted by LMIC researchers, and (3) accessible to them. METHOD: Using the databases PubMed, PsychInfo, and PILOTS, we systematically searched for peer-reviewed articles on traumatic stress published in any language in the year 2012. Out of the 3,123 unique papers identified, we coded a random sample (N=1,000) for study, author, article, and journal characteristics. RESULTS: Although our sample involved research in 56 different countries, most papers (87%) involved research in HIC, with 51% of all papers describing studies in the United States. In 88% of the papers, the author team was affiliated with HIC only. Less than 5% of all author teams involved collaborations between HIC and LMIC researchers. Moreover, 45% of the articles on LMIC studies published by a HIC corresponding author did not involve any LMIC co-authors. LMIC researchers appeared to publish empirical studies in lower impact journals. Of the 1,000 articles in our sample, 32% were open access and 10% were made available via different means; over half of the papers were not accessible without subscription. CONCLUSIONS: Traumatic stress research is increasingly global but still strongly dominated by HIC. Important opportunities to build capacity in LMIC appear to be missed. Implications toward more international traumatic stress research are discussed.

11.
Psychophysiology ; 51(3): 236-46, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24397333

RESUMO

The current study adopted the trauma film paradigm to examine potential moderators affecting heart rate (HR) as an indicator of peritraumatic psychological states and as a predictor of intrusive memories. We replicated previous findings that perifilm HR decreases predicted the development of intrusive images and further showed this effect to be specific to images rather than thoughts, and to detail rather than gist recognition memory. Moreover, a group of individuals showing both an atypical sudden reduction in HR after a startle stimulus and higher trait dissociation was identified. Only among these individuals was lower perifilm HR found to indicate higher state dissociation, fear, and anxiety, along with reduced vividness of intrusions. The current findings emphasize how peritraumatic physiological responses relate to emotional reactions and intrusive memory. The moderating role of individual difference in stress defense style was highlighted.


Assuntos
Frequência Cardíaca/fisiologia , Rememoração Mental/fisiologia , Reflexo de Sobressalto/fisiologia , Transtornos de Estresse Pós-Traumáticos/fisiopatologia , Adolescente , Adulto , Ansiedade/fisiopatologia , Medo/fisiologia , Feminino , Humanos , Masculino , Estimulação Luminosa , Adulto Jovem
12.
Child Abuse Negl ; 35(1): 58-68, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21334068

RESUMO

OBJECTIVE: This study aimed to investigate child physical abuse (CPA) while taking into account the more rigorous definitions of CPA in the Chinese societies. The prevalence of CPA and CPA-related PTSD were estimated, together with the examination of peri-traumatic subjective reactions and their impacts on PTSD. METHODS: In a Taiwanese sample of 1966 4th to 8th graders, the Chinese version of UCLA PTSD Reaction Index for DSM-IV (Steinberg, Brymer, Decker, & Pynoos, 2004) was used to investigate the lifetime exposure to CPA. A sub-sample of 236 traumatized CPA victims was examined with respect to related PTSD symptoms. RESULTS: Thirty-four percent of the children had been exposed to CPA. The estimated current prevalence of full and partial PTSD was 13.6% and 16.9%, respectively. CONCLUSIONS: The current CPA prevalence was found to be higher than the Western countries, but lower than the previous findings in other East Asian societies. The full PTSD prevalence was close to the findings in the Western countries, whereas sub-clinical PTSD was less observed in Taiwan. Peri-traumatic subjective reactions, that is, Criterion A2 and perceived threat, were shown to be major predictors of PTSD symptom severity. The role of attitudes of child discipline in the Chinese societies in the prevalence of CPA and CPA-related PTSD is discussed. PRACTICE IMPLICATIONS: By providing explicit epidemiological information of CPA and CPA-related PTSD in Taiwan, the current study extends our understanding of CPA and CPA-related PTSD more broadly from Western countries to the Eastern societies. By separately investigating CPA relating to different perpetrators, cross-study comparison is enhanced. In the current study, the significance of considering cultural background in defining CPA and examining CPA-related PTSD was pointed out. Meanwhile, the role of victims' subjective reactions in the psychopathology of PTSD is highlighted. The findings and discussions could contribute for generating a more sophisticated clinical practice, especially with Asian or Chinese cases.


Assuntos
Abuso Sexual na Infância/etnologia , Abuso Sexual na Infância/psicologia , Vítimas de Crime/psicologia , Cultura , Transtornos de Estresse Pós-Traumáticos/etnologia , Adolescente , Criança , China/etnologia , Feminino , Humanos , Entrevistas como Assunto , Masculino , Transtornos de Estresse Pós-Traumáticos/psicologia , Taiwan
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