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1.
BMC Psychiatry ; 24(1): 425, 2024 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-38844888

RESUMO

This longitudinal study in Mainland China (2021-2022) explored the impact of adverse childhood experiences (ACEs) on complex posttraumatic stress disorder (CPTSD) symptoms, with a focus on the role of self-compassion. Among 18,933 surveyed university students, 21.2% reported experiencing at least one ACE. Results revealed a clear relationship between ACEs and CPTSD symptoms. Furthermore, self-compassion, particularly the dimensions of self-judgment and isolation, moderated the association between retrospective ACEs and posttraumatic stress disorder (PTSD) and disturbance in self-organization (DSO) symptoms. These findings highlight the enduring impact of ACEs on CPTSD symptoms and emphasize the importance of early identification and targeted interventions, especially addressing self-judgment and isolation, to mitigate CPTSD risk among young Chinese adults.


Assuntos
Experiências Adversas da Infância , Empatia , Transtornos de Estresse Pós-Traumáticos , Humanos , Transtornos de Estresse Pós-Traumáticos/psicologia , Masculino , Feminino , China , Estudos Longitudinais , Adulto Jovem , Experiências Adversas da Infância/psicologia , Adulto , Autoimagem , Adolescente , Estudos Retrospectivos , Estudantes/psicologia , População do Leste Asiático
2.
J Ment Health ; : 1-10, 2024 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-38850018

RESUMO

BACKGROUND: Self-compassion (SC), reflecting self-attitude and self-connectedness, has proven to be a modifiable factor in promoting mental health outcomes. Increasingly, SC is recognized as a multidimensional construct consisting of six dimensions, rather than a single dimension. OBJECTIVES: First, this study adopted a person-centered approach to explore profiles of SC dimensions in Chinese young adults. Second, the study examined the predictive effects of SC profiles on mental health outcomes. METHODS: In February 2020, young adults (N = 1164) were invited to complete the 26-item Neff's Self-Compassion Scale online. Three months later, the same subjects (N = 1099) reported their levels of depressive symptoms, posttraumatic stress disorder (PTSD) symptoms, and posttraumatic growth (PTG). RESULTS: After controlling for retrospective ACEs, four classes best characterized the profiles: self-compassionate (26.7%, N = 294), self-uncompassionate (12.3%, N = 135), average (55.9%, N = 614), and detached groups (5.1%, N = 56). Young adults in the self-compassionate group adjusted the best (with the highest level of PTG and the lowest levels of depressive and PTSD symptoms). Adults in the self-uncompassionate group demonstrated the poorest mental health outcomes (with the lowest level of PTG and the highest levels of depressive and PTSD symptoms). Young adults in the average group obtained more PTG than adults in the detached group (p < .01), but did not differ significantly in depressive and PTSD symptoms (p > .05). CONCLUSION: The compassionate profile is the most adaptable for young adults among all groups. This study highlights the limitations of representing the relative balance of SC with a composite score.

3.
Psychiatry Res ; 336: 115872, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38581767

RESUMO

OBJECTIVE: To enhance understanding of the longitudinal progression of complex posttraumatic stress disorder (CPTSD) symptoms, this longitudinal study examined how CPTSD symptoms interact over time in Chinese college students with childhood trauma. METHODS: From 18,933 college students who took part in two surveys 12 months apart, 4,006 participants who reported adverse childhood experiences were screened. Cross-sectional network comparisons and cross-lagged panel network (CLPN) analysis characterized interactions among CPTSD symptoms. RESULTS: In the cross-sectional networks, feeling like a failure and avoid activities reminiscent of the trauma were the central symptoms. Takes long time to calm down and exaggerated startle are important bridge symptoms in the two networks respectively. The comparison of cross-sectional networks indicates that the global network strength was stable. The findings of the CLPN model reveal that feel worthless and feel like a failure had the highest "out" expected influence; exaggerated startle and avoid thoughts and feelings about the trauma had the highest "in" expected influence. CONCLUSIONS: By conducting cross-sectional network analyses, the study illuminated the attributes of CPTSD networks across various time points. Additionally, the CLPN analysis uncovered the longitudinal patterns of CPTSD symptoms.


Assuntos
Experiências Adversas da Infância , Transtornos de Estresse Pós-Traumáticos , Estudantes , Humanos , Transtornos de Estresse Pós-Traumáticos/psicologia , Transtornos de Estresse Pós-Traumáticos/fisiopatologia , Masculino , Estudos Longitudinais , Feminino , Estudantes/psicologia , Estudos Transversais , Adulto Jovem , China , Universidades , Adulto , Adolescente
4.
Child Abuse Negl ; 151: 106736, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38522146

RESUMO

BACKGROUND: Although people strive for meaning in life, life is full of experiences that challenge meaning. According to Bowen's family systems theory, the family is both a relational and an emotional system in which family members influence and are influenced by each other. Invalidating environment, reflecting a deficient family emotional setting, may be a key influencing factor in diminishing meaning in life. Existing studies have not directly explored the effects of the invalidating environment on meaning in life and its underlying mechanism. OBJECTIVE: Guided by Bowen's family systems theory, this study aims to explore the relationship between invalidating environment and meaning in life, as well as the mediating effects of regulatory emotional self-efficacy and the satisfaction of basic psychological needs. METHODS: A sample of 555 university students (62.5 % female, 37.5 % male; Mage =19.13 years old, SD = 1.72) completed questionnaires regarding demographics, invalidating environment, meaning in life, regulatory emotional self-efficacy, and basic psychological needs satisfaction. RESULTS: Results revealed that: (a) invalidating environment negatively predicts meaning in life; (b) regulatory emotional self-efficacy and basic psychological needs satisfaction serve as both independent and chain mediators between invalidating environment and meaning in life. CONCLUSION: Invalidating environment affects meaning in life through regulatory emotional self-efficacy and basic psychological needs satisfaction. This finding has significant theoretical implications and provides a feasible pathway to improve children's meaning in life at both the parent and child levels.


Assuntos
Família , Autoeficácia , Criança , Humanos , Masculino , Feminino , Adulto Jovem , Adulto , Emoções , Satisfação Pessoal , Pais
5.
Behav Sci (Basel) ; 14(3)2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38540541

RESUMO

OBJECTIVE: The present study aimed to explore the relationship between insecure attachment (attachment anxiety and avoidance) and depressive symptoms in Chinese young adults as well as the mediating roles of positive and negative self-compassion. METHODS: An online survey was administered among college students in mainland China. This involved their completion of questionnaires encompassing socio-demographic details, attachment anxiety, attachment avoidance, self-compassion, and depressive symptoms. RESULTS: Attachment anxiety and avoidance exhibited connections with depressive symptoms through increased negative self-compassion and decreased positive self-compassion. Attachment anxiety was associated with depressive symptoms primarily through the mediating effect of negative self-compassion. Conversely, attachment avoidance was related to depressive symptoms mainly through the mediating role of positive self-compassion. CONCLUSIONS: Attachment anxiety exerted a slightly stronger influence on negative self-compassion, whereas attachment avoidance exhibited a more prominent impact on positive self-compassion. Despite these differences, both attachment styles were comparable in their overall influence on depressive symptoms. This revelation provides fresh insights into the relationship between insecure attachment and depressive symptoms among young adults, underscoring the importance for intervention program development.

6.
Child Abuse Negl ; 146: 106503, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37922615

RESUMO

BACKGROUND AND OBJECTIVES: College students who have experienced childhood maltreatment commonly exhibit adverse psychological consequences such as post-traumatic stress disorder (PTSD) and depression. The aim of this study is to use network analysis to investigate the gender differences in complex connections among various types of childhood maltreatment, PTSD, and depression. METHODS: This study involved 481 participants (M = 19.25 years, 54.5 % female) who were selected from a larger sample of 5231 college students. These participants had experienced childhood maltreatment and exhibited significant clinical symptoms of PTSD and depression. The participants completed validated measures that assessed childhood trauma, PTSD, and depression. RESULTS: The network analysis performed on the entire sample revealed robust connections among various types of childhood maltreatment, symptom clusters of PTSD, and depression. The most central symptom that emerged was negative alterations in cognitions and mood (NACM), with emotional abuse displaying the highest centrality measure among the various types of childhood maltreatment. Upon comparing the subnetworks, the centrality analysis identified significant gender differences in nodes such as sexual abuse, physical neglect, emotional neglect, and avoidance. CONCLUSIONS: The study's findings confirm that various forms of childhood abuse have intricate and multifaceted connections with depression and PTSD symptoms in adulthood. The study suggests that NACM could be the most significant symptom, and emotional abuse may play a vital role in adverse psychological outcomes. Furthermore, notable gender discrepancies were identified in the relationship between various forms of maltreatment and psychopathological symptoms.


Assuntos
Maus-Tratos Infantis , Transtornos de Estresse Pós-Traumáticos , Humanos , Feminino , Criança , Adulto Jovem , Masculino , Transtornos de Estresse Pós-Traumáticos/epidemiologia , Transtornos de Estresse Pós-Traumáticos/psicologia , Depressão/epidemiologia , Depressão/psicologia , Fatores Sexuais , Maus-Tratos Infantis/psicologia , Estudantes
7.
Psychol Trauma ; 2023 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-37843524

RESUMO

OBJECTIVE: To advance understanding of the development of complex posttraumatic stress disorder (CPTSD) symptoms longitudinally and facilitate future treatments, the present study investigated changes in the network of CPTSD symptoms among Chinese college students with childhood trauma. METHOD: A longitudinal study was conducted with college students, following them three times at 3-month intervals. CPTSD symptoms were measured using the International Trauma Questionnaire, and childhood trauma was assessed by the revised Adverse Childhood Experiences Scale. The final sample consisted of 294 participants with childhood trauma at baseline measurement (28.9% were males, Mage = 20.76 years). Comparisons of cross-sectional networks and cross-lagged panel network (CLPN) analysis were performed to characterize the features and changes of interactions among CPTSD symptoms. RESULTS: Sense of failure and isolation were the core symptoms in the cross-sectional networks of CPTSD symptoms. The comparison of cross-sectional networks indicated that the global network strength was stable, and no node's strength centrality and only one edge weight changed significantly from Time 1 (T1) to Time 3 (T3). The findings of the CLPN model reveal that worthlessness, difficulties with intimacy, and flashbacks have the highest out-expected influence. In the T1-T3 network, the strongest edge was from worthlessness to sense of failure. CONCLUSIONS: Cross-sectional network analyses and comparisons revealed the characteristics of CPTSD networks at multiple time points, while the CLPN analysis identified the longitudinal dynamics of CPTSD symptoms. These provide insights for designing more targeted intervention plans for college students with childhood trauma. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

8.
Children (Basel) ; 10(2)2023 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-36832535

RESUMO

Objectives: This study aimed to examine the associations between warm and harsh parenting and adolescent well-being, and the mediating effects of self-kindness and self-judgment, in relationships. Moreover, this study investigated developmental differences across three adolescence stages (early, middle, and late). Methods: In total, 14,776 Chinese adolescents (mean age = 13.53 ± 2.08, 52.3% males), including individuals in early (10-12 years old, N = 5055), middle (13-15 years old, N = 6714), and late adolescence (16-18 years old, N = 3007) participated in this study. All the adolescents rated their levels of warm and harsh parenting, self-kindness and self-judgment, and well-being. Structural equation modeling (SEM) was adopted to examine the mediation model. Multi-group analysis was conducted to investigate differences in the mediation model across the different developmental stages. Results: Both warm and harsh parenting were related to adolescent well-being through the mediating effects of self-kindness and self-judgment. However, warm parenting exerted a more substantial impact on adolescent well-being. Self-kindness had a more robust mediating effect than self-judgment in relationships. Moreover, harsh parenting had a weaker impact on adolescent well-being in late adolescence than in early and middle adolescence. Warm parenting had a more significant impact on adolescent well-being in early adolescence than in middle and late adolescence. Conclusions: Overall, warm parenting had a more substantial effect than harsh parenting on adolescent well-being. The findings also highlighted the crucial mediating effect of self-kindness in the relationships between parenting and well-being. Moreover, this study also indicated the importance of warm parenting in early adolescence. Intervention programs should focus on enhancing the level of warm parenting to promote self-kindness in adolescents, in order to improve their well-being.

9.
Curr Psychol ; : 1-12, 2023 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-36845203

RESUMO

The integrative model of parenting has highlighted the integral contributions of parental involvement (quantity) and parenting style (quality) to adolescent psychological adjustments. The first aim of this study was to adopt the person-centered approach to identify profiles of parental involvement (quantity) and parenting styles (quality). The second purpose was to examine the associations between different parenting profiles and adolescent psychological adjustments. A cross-sectional online survey with families (N = 930) that included fathers, mothers, and adolescents (50% female, M age = 14.37 ± 2.31) was conducted in mainland China. The fathers and mothers reported their level of parental involvement; the adolescents rated fathers' and mothers' parenting styles, as well as their own levels of anxiety symptoms, depression symptoms, and loneliness. Latent profile analysis was adopted to identify parenting profiles using the standardized scores of fathers' and mothers' involvement and style (warmth and rejection). The regression mixture model was used to examine the relationships between different parenting profiles and adolescent psychological adjustments. Four classes best characterized the parenting behaviors: warm involvement (52.6%), neglecting noninvolvement (21.4%), rejecting noninvolvement (21.4%), and rejecting involvement (4.6%). Adolescents in the warm involvement group scored lowest on anxiety symptoms, depression symptoms, and loneliness. Adolescents in rejecting involvement group scored highest on psychological adjustment indicators. Adolescents in neglecting noninvolvement group scored lower on anxiety symptoms than those in rejecting noninvolvement group. Adolescents in the warm involvement group adjusted best, while adolescents in the rejecting involvement group adjusted worst among all groups. To promote adolescents' mental health, intervention programs need to consider both parental involvement and parenting styles simultaneously.

10.
Child Adolesc Psychiatry Ment Health ; 17(1): 11, 2023 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-36681826

RESUMO

BACKGROUND: The importance of preventing and treating adolescent depression has been gradually recognized in Chinese society, especially in the context of the COVID-19 pandemic. Early screening is the first step. The Patient Health Questionnaire-9 (PHQ-9) is a leading scale in the field of depression screening. To improve screening efficiency in large-scale screening, an even shorten scale is desirable. The PHQ-2, which only included two items measuring anhedonia and depressed mood, is an ultra-form of the PHQ-9. However, emerging evidence suggests that there may be a better short form for the PHQ-9, especially for adolescents. Therefore, using two large samples of Chinese adolescents, this study aimed to identify the core items of the PHQ-9 and examine the short form consisting of core items. METHODS: Surveys were conducted among primary and middle school students in two Chinese cities with different economic levels during the COVID-19 pandemic. Two gender-balanced samples aged 10 to 17 (nSample 1 = 67281, nSample 2 = 16726) were collected. Network analysis was used to identify the core items of the PHQ-9, which were extracted to combine a short version. Reliability, concurrent validity, and the receiver operating characteristic curve (ROC) of the short form were examined. Analyses were gender-stratified. RESULTS: Network analysis identified fatigue and depressed mood as core items in the PHQ-9 among Chinese adolescents. Items measuring Fatigue and Mood were combined to be a new PHQ-2 (PHQ-2 N). The PHQ-2 N displayed satisfactory internal consistency and current validity. Taking the PHQ-9 as a reference, the PHQ-2 N showed higher ROC areas and better sensitivity and specificity than the PHQ-2. The optimal cutoff score for the PHQ-2 N was 2 or 3. CONCLUSIONS: Fatigue and depressed mood are the central symptoms of the depressive symptom network. The PHQ-2 N has satisfactory psychometric properties and can be used in rapid depression screening among Chinese adolescents.

11.
Child Adolesc Psychiatry Ment Health ; 16(1): 102, 2022 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-36517917

RESUMO

BACKGROUND: It is yet to be clarified if and how parenting stress was linked to adolescent depressive symptoms during the pandemic. OBJECTIVES: This study adopted an interdependent approach to examine the relationship between parenting stress and adolescent depressive symptoms in Chinese families. It then examined the mediating effects of overt and covert coparenting conflict behaviors. METHODS: As a national survey, data were obtained from different regions in China. Fathers, mothers, and adolescents from 1031 families participated in this study. The fathers and mothers reported parenting stress; the adolescents rated their fathers and mothers' overt and covert coparenting conflict behaviors and their own depressive symptoms. RESULTS: Maternal parenting stress was related to adolescent depressive symptoms through the mediating effects of paternal overt and maternal covert coparenting conflict behaviors. Both paternal and maternal parenting stress were directly related to adolescent depressive symptoms. However, maternal parenting stress had a more substantial effect on adolescent depressive symptoms than paternal parenting stress. CONCLUSIONS: The findings support the effects of parenting stress on adolescent depressive symptoms. The study also highlights the mediating roles of paternal overt and maternal covert coparenting conflict behaviors in relationships.

12.
Curr Psychol ; : 1-12, 2022 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-35846239

RESUMO

The multi-dimensionality of self-compassion and its influence on college students' adjustments have not been widely examined during the COVID-19 pandemic. The current study aims to explore profiles of self-compassion dimensions in Chinese college students and examine the predictive effects of different profiles on students' adjustment outcomes. A longitudinal online survey of college students was conducted in mainland China. In May of 2020, college students (N = 1361) completed Neff's Self-Compassion Scale-Short Form during the home quarantine period. Six months after the baseline assessment, students (N = 717) reported their level of anxiety symptoms, depression symptoms, insomnia symptoms, complex post-traumatic stress (CPTSD) symptoms, post-traumatic growth (PTG), and positive youth development (PYD). A latent profile analysis was adopted to identify profiles of self-compassion dimensions. A longitudinal regression mixture model was used to examine the predictive effects of different self-compassion profiles on college students' adjustment outcomes. Three classes best characterized the self-compassion dimensions of college students: the compassionate group (54.1%), the uncompassionate group (38.6%), and the extremely uncompassionate group (7.3%). College students in the compassionate group scored significantly higher on positive adjustment indicators (PTG and PYD), and significantly lower on negative adjustment indicators (anxiety, depression, insomnia, and CPTSD symptoms) than students in the other two groups. College students in the uncompassionate group scored significantly lower on negative indicators, and higher on PYD scores than students in the extremely uncompassionate group, but did not differ in PTG levels from students in the extremely uncompassionate group. College students in the compassionate group adjusted best across groups. The limitations that using a composite score to represent the relative balance of self-compassion dimensions were highlighted. Intervention programs need to focus on improving the level of positive self-responses in college students.

13.
Appl Psychol Health Well Being ; 14(2): 434-452, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-34693632

RESUMO

Parental depressive symptoms and their related factors have not been widely examined during the COVID-19 pandemic. Therefore, the current study examined the actor and partner associations of work-family conflict and parental depressive symptoms. Considering the new demands and challenges for families during the COVID-19 pandemic, we further explored the moderation effect of coparenting. A cross-sectional online survey with 985 paired fathers and mothers was conducted in Mainland China. In 11.6% of families, only mothers reported moderate to severe depressive symptoms; in 10.6% families, only fathers reported moderate to severe depressive symptoms; in 9.5% families, the mother and father reported mild to moderate depressive symptoms. Results of the actor-partner interdependence model showed that parental family-to-work conflict was negatively associated with their own depressive symptoms. The negative actor association of maternal family-to-work conflict and depressive symptoms was moderated by undermining coparenting. The partner effects of maternal family-to-work and work-to-family conflicts on paternal depressive symptoms were moderated by undermining coparenting. Moreover, supportive coparenting moderated the actor association of work-to-family conflict and the depressive symptoms of fathers. Results highlight the importance of family-to-work conflict and family function for parental depressive symptoms. These findings can help promote parental well-being during the COVID-19 pandemic.


Assuntos
COVID-19 , Conflito Familiar , China/epidemiologia , Estudos Transversais , Depressão/epidemiologia , Feminino , Humanos , Masculino , Pandemias , Poder Familiar , Pais
14.
Risk Manag Healthc Policy ; 14: 4673-4683, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34824554

RESUMO

BACKGROUND: Physical activity and self-compassion are closely related to individuals' mental health (eg, depression). However, most studies only examined their independent roles in mental health without considering the potential interaction between the two variables. The present study aimed to investigate the independent and joint associations between physical activity (PA) and self-compassion (SC) on depression symptoms and examine the additive interaction between PA and SC. METHODS: A cross-sectional design was utilized in the present descriptive study. By recruiting participants via social media platforms, 1846 Chinese college students completed International Physical Activity Questionnaire Short Form, the Self-Compassion Scale-Short Form, the 9-item Patient Health Questionnaire, and items regarding socio-demographic information. Independent and joint roles of low-level PA (LPA) and low-level SC (LSC) on depression symptoms were examined by logistic regression models. Additive interaction between LPA and LSC on depression symptoms was examined by the following indices: relative excess risk due to interaction (RERI), attributable proportion (AP), and synergy index (S). Socio-demographic variables were included in the models as covariates. RESULTS: Both LPA (OR = 1.47 [1.16, 1.86]) and LSC (OR = 5.74 [3.89, 8.45]) were independently associated with higher probability of depression symptoms. Combining LPA and LSC led to an additive interaction and greatly increased the odds of depression symptoms (OR = 9.62 [5.38, 17.22]; RERI = 2.47 [0.19, 4.75], AP = 0.25 [0.05, 0.44], S = 1.38 [1.02, 1.87]). CONCLUSION: Both LPA and LSC were associated with an increased risk of depression symptoms. Moreover, combining LPA and LSC may develop an additive risk for depression symptoms. Future research and clinical intervention could integrate PA and SC to find a better way to resist depression symptoms.

15.
Nanoscale ; 13(20): 9436-9445, 2021 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-34008608

RESUMO

Formation of Ge-rich prismatic inclusions in the hexagonal SiGe shell of GaP-Si-SiGe nanowires is reported and discussed in relation to a growth model that explains their origin. An accurate TEM/EDX analysis shows that such prisms develop right on top of any {112[combining macron]0} facet present on the inner GaP-Si surface, with the base matching the whole facet extension, as large as tens of nanometers, and extending within the SiGe shell up to a thickness of comparable size. An enrichment in Ge by around 5% is recognized within such regions. A phase-field growth model, tackling both the morphological and compositional evolution of the SiGe shell during growth, is exploited to assess the mechanism behind the prism formation. A kinetic segregation process, stemming from the difference in surface mobility between Ge (faster) and Si (slower), is shown to take place, in combination with the evolution of the SiGe shell morphology. Actually, the latter moves from the one templated by the underlying GaP-Si core, including both {101[combining macron]0} and {112[combining macron]0} facets, to the more energetically convenient hexagon, bounded by {101[combining macron]0} facets only. Simulations are shown to accurately reproduce the experimental observations for both regular and asymmetric nanowires. It is then discussed how a careful control of the GaP core faceting, as well as a proper modulation of the shell growth rate, allows for direct control of the appearance and size of the Ge-rich prisms. This tunability paves the way for a possible exploitation of these lower-gap regions for advanced designs of band-gap-engineering.

16.
Nano Lett ; 21(8): 3619-3625, 2021 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-33843244

RESUMO

Recently synthesized hexagonal group IV materials are a promising platform to realize efficient light emission that is closely integrated with electronics. A high crystal quality is essential to assess the intrinsic electronic and optical properties of these materials unaffected by structural defects. Here, we identify a previously unknown partial planar defect in materials with a type I3 basal stacking fault and investigate its structural and electronic properties. Electron microscopy and atomistic modeling are used to reconstruct and visualize this stacking fault and its terminating dislocations in the crystal. From band structure calculations coupled to photoluminescence measurements, we conclude that the I3 defect does not create states within the hex-Ge and hex-Si band gap. Therefore, the defect is not detrimental to the optoelectronic properties of the hex-SiGe materials family. Finally, highlighting the properties of this defect can be of great interest to the community of hex-III-Ns, where this defect is also present.

17.
Nature ; 580(7802): 205-209, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32269353

RESUMO

Silicon crystallized in the usual cubic (diamond) lattice structure has dominated the electronics industry for more than half a century. However, cubic silicon (Si), germanium (Ge) and SiGe alloys are all indirect-bandgap semiconductors that cannot emit light efficiently. The goal1 of achieving efficient light emission from group-IV materials in silicon technology has been elusive for decades2-6. Here we demonstrate efficient light emission from direct-bandgap hexagonal Ge and SiGe alloys. We measure a sub-nanosecond, temperature-insensitive radiative recombination lifetime and observe an emission yield similar to that of direct-bandgap group-III-V semiconductors. Moreover, we demonstrate that, by controlling the composition of the hexagonal SiGe alloy, the emission wavelength can be continuously tuned over a broad range, while preserving the direct bandgap. Our experimental findings are in excellent quantitative agreement with ab initio theory. Hexagonal SiGe embodies an ideal material system in which to combine electronic and optoelectronic functionalities on a single chip, opening the way towards integrated device concepts and information-processing technologies.

18.
Nano Lett ; 19(7): 4702-4711, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31203630

RESUMO

One of the current challenges in nanoscience is tailoring the phononic properties of a material. This has long been a rather elusive task because several phonons have wavelengths in the nanometer range. Thus, high quality nanostructuring at that length-scale, unavailable until recently, is necessary for engineering the phonon spectrum. Here we report on the continuous tuning of the phononic properties of a twinning superlattice GaP nanowire by controlling its periodicity. Our experimental results, based on Raman spectroscopy and rationalized by means of ab initio theoretical calculations, give insight into the relation between local crystal structure, overall lattice symmetry, and vibrational properties, demonstrating how material engineering at the nanoscale can be successfully employed in the rational design of the phonon spectrum of a material.

19.
Nanotechnology ; 30(29): 295602, 2019 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-30840942

RESUMO

We demonstrate the merits of an unexplored precursor, tetrasilane (Si4H10), as compared to disilane (Si2H6) for the growth of defect-free, epitaxial hexagonal silicon (Si). We investigate the growth kinetics of hexagonal Si shells epitaxially around defect-free wurtzite gallium phosphide (GaP) nanowires. Two temperature regimes are identified, representing two different surface reaction mechanisms for both types of precursors. Growth in the low temperature regime (415 °C-600 °C) is rate limited by interaction between the Si surface and the adsorbates, and in the high temperature regime (600 °C-735 °C) by chemisorption. The activation energy of the Si shell growth is 2.4 ± 0.2 eV for Si2H6 and 1.5 ± 0.1 eV for Si4H10 in the low temperature regime. We observe inverse tapering of the Si shells and explain this phenomenon by a basic diffusion model where the substrate acts as a particle sink. Most importantly, we show that, by using Si4H10 as a precursor instead of Si2H6, non-tapered Si shells can be grown with at least 50 times higher growth rate below 460 °C. The lower growth temperature may help to reduce the incorporation of impurities resulting from the growth of GaP.

20.
Support Care Cancer ; 27(8): 2903-2909, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30560420

RESUMO

PURPOSE: Insomnia symptoms are common among women who have undergone surgery for breast cancer. Personality traits are also believed to have an impact on sleep. However, there are no reports to address the effects of personality traits on sleep in women with breast cancer. This study examined the separate and competing roles of neuroticism, anxiety sensitivity, and optimism in predicting post-surgery insomnia symptoms. METHODS: Women with breast cancer (n = 749) were enrolled the week prior to surgery and required to complete a demographic questionnaire, the Chinese version of Neuroticism subscale of NEO-Five Factor Inventory (CV-N-NEO-FFI), Anxiety Sensitivity Index-3 (CV-ASI-3), and Life Orientation Test-Revised (CV-LOT-R). Four weeks post-surgery, the Chinese version of Insomnia Severity Index (CV-ISI) was administered to evaluate insomnia symptoms. RESULTS: Neuroticism (ß = 0.317, p < 0.001), anxiety sensitivity (ß = 0.220, p < 0.001), and optimism (ß = - 0.332, p < 0.001) could predict post-surgery insomnia symptoms. When putting them together into one stepwise regression, optimism (ß = - 0.215, p < 0.001) became the statistically most important predictor for insomnia symptoms. Optimism suppressed the predictions of insomnia symptoms provided by neuroticism (ß = 0.114, p < 0.001) and anxiety sensitivity (ß = 0.079, p < 0.001). CONCLUSION: Neuroticism and anxiety sensitivity positively predicted insomnia, but optimism negatively predicted insomnia. In particular, optimism plays a more important role in post-surgery insomnia symptoms in women with breast cancer compared to neuroticism and anxiety sensitivity. Sleep intervention in women with breast cancer should focus on enhancing their optimism level.


Assuntos
Transtornos de Ansiedade/psicologia , Ansiedade/psicologia , Neoplasias da Mama/psicologia , Neoplasias da Mama/cirurgia , Neuroticismo , Otimismo , Distúrbios do Início e da Manutenção do Sono/psicologia , Adulto , Ansiedade/epidemiologia , Transtornos de Ansiedade/epidemiologia , Neoplasias da Mama/epidemiologia , China/epidemiologia , Feminino , Humanos , Pessoa de Meia-Idade , Autoimagem , Distúrbios do Início e da Manutenção do Sono/epidemiologia , Inquéritos e Questionários
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