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1.
Psych J ; 13(3): 486-493, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38298152

RESUMO

Theory of mind (ToM) and empathy are considered key components of social cognition that are often impaired in individuals with autism spectrum disorders (ASD). However, it remains unclear whether individuals with high levels of autistic traits exhibit similar impairments in these two functions. This study examined the affective and cognitive domains of ToM and empathy in individuals with high levels of autistic traits. We recruited 84 participants with high levels and 78 participants with low levels of autistic traits to complete a set of self-reported checklists and performance-based tasks capturing affective and cognitive components of ToM and empathy. The results showed that participants with high levels of autistic traits exhibited significant impairments in cognitive but not in affective ToM and empathy compared with their counterparts with low levels of autistic traits. We also found that empathy impairments in people with high levels of autistic traits were confounded by alexithymia and depressive traits.


Assuntos
Transtorno do Espectro Autista , Empatia , Teoria da Mente , Humanos , Masculino , Feminino , Transtorno do Espectro Autista/psicologia , Adulto , Cognição/fisiologia , Adulto Jovem , Sintomas Afetivos , Transtorno Autístico/psicologia
2.
Psych J ; 13(1): 145-148, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37905895

RESUMO

This study applied two incentive delay tasks involving social and non-social incentive types to 76 pairs of participants with high and low depressive symptoms. The results suggest that higher levels of depressive symptoms are correlated with abnormalities in social and non-social reward processing even in the healthy populations.


Assuntos
Depressão , Recompensa , Humanos , Motivação
3.
Laryngoscope ; 134(2): 803-806, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37658737

RESUMO

INTRODUCTION: With vast improvements in imaging and endoscopic technology, there has been a massive shift towards in office procedures for various laryngeal disorders with significant health system and patient benefits. Another benefit which has yet to be investigated is the potential environmental effects and waste reduction of in-office laryngeal procedures over traditional operating room surgery. OBJECTIVES: The purpose of this study is to perform a waste audit and compare the results between operating room and in-office laser laryngeal surgery. METHODS: Ten cases of in-office and operating room laser laryngeal surgery, performed for recurrent respiratory papillomatosis, were subjected to a waste audit with four waste streams identified. Recyclable, general waste, anesthesia source and sharps. All waste was included from the time of case preparation to termination. RESULTS: The cases were extremely homogeneous in the waste produced. The mean waste total produced for the operating room laser surgery was 2972 g of which 18% was recoverable/recyclable. Contamination rate was very low. Recycling was performed very well by nursing/prep staff; however, anesthesia was not recovering 13% of potential materials. The in-office waste produced was approximately one tenth of the operating room waste with almost all delegated into general waste. Potentially divertible/recyclable materials accounted for 38% of the waste in-office procedures. CONCLUSIONS: In-office laryngeal procedures produce 13% of waste compared to surgery performed for similar pathology. These procedures are cost effective, safe and have been demonstrated to enhance environmental sustainability. LEVEL OF EVIDENCE: NA Laryngoscope, 134:803-806, 2024.


Assuntos
Doenças da Laringe , Laringoscópios , Laringe , Terapia a Laser , Humanos , Laringe/cirurgia , Doenças da Laringe/cirurgia , Procedimentos Cirúrgicos Ambulatórios , Salas Cirúrgicas
4.
Schizophr Res Cogn ; 35: 100297, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38115992

RESUMO

Range adaptation refers to the representation of a stimulus value based on its relative position in the range of pre-experienced values. Altered range adaptation in value representation may be related to motivation and pleasure (MAP) deficit in schizophrenia (SCZ). This follow-up study examined the relationship between range adaptation performance and MAP symptoms in SCZ patients. We recruited 26 schizophrenia patients and followed them for 1 year. They completed an experimental task for estimating their range adaptation to outcome value (OV) and expected value (EV) at baseline and after 1 year. At baseline, we found a marginally significant and negative correlation between OV adaptation and avolition symptoms in SCZ patients. Moreover, the 1-year change of EV adaptation was significantly and negatively correlated with the change of self-report pleasure experience. Our results suggest that range adaptation may track the variations of MAP symptoms in SCZ.

5.
Asian J Psychiatr ; 92: 103880, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38157714

RESUMO

Anhedonia and amotivation are core symptoms of schizophrenia (SCZ) and major depressive disorder (MDD). Reward processing involves constructing and contrasting the representations for expected value (EV) and outcome value (OV) of a given stimulus, a phenomenon termed range adaptation. Impaired range adaptation can lead to anhedonia and amotivation. This study aimed to examine range adaptation in SCZ patients and MDD patients. Fifty SCZ, 46 MDD patients and 56 controls completed the Effort-based Pleasure Experience Task to measure EV and OV adaptation. SCZ and MDD patients showed altered range adaptation, albeit in different patterns. SCZ patients exhibited over-adaptation to OV and reduced adaptation to EV. By contrast, MDD patients exhibited diminished OV adaptation but intact EV adaptation. Both OV and EV adaptation were correlated with anhedonia and amotivation in SCZ and MDD. Taken together, our findings suggest that range adaptation is altered in both SCZ and MDD patients. Associations of OV and EV adaptation with anhedonia and amotivation were consistently found in SCZ and MDD patients. Impaired range adaptation in SCZ and MDD patients may be putative neural mechanisms and potential intervention targets for anhedonia and amotivation.


Assuntos
Transtorno Depressivo Maior , Esquizofrenia , Humanos , Anedonia , Depressão , Motivação , Recompensa
6.
Artigo em Inglês | MEDLINE | ID: mdl-37395812

RESUMO

Reward motivation in individuals with high levels of negative schizotypal traits (NS) has been found to be lower than that in their counterparts. But it is unclear that whether their reward motivation adaptively changes with external effort-reward ratio, and what resting-state functional connectivity (rsFC) is associated with this change. Thirty-five individuals with high levels of NS and 44 individuals with low levels of NS were recruited. A 3T resting-state functional brain scan and a novel reward motivation adaptation behavioural task were administrated in all participants. The behavioural task was manipulated with three conditions (effort > reward condition vs. effort < reward condition vs. effort = reward condition). Under each condition were rated 'wanting' and 'liking' for rewards. The seed-based voxel-wise rsFC analysis was conducted to explore the rsFCs associated with the 'wanting' and 'liking' ratings in individuals with high levels of NS. 'Wanting' and 'liking' ratings of individuals with high levels of NS significantly declined in the effort > reward condition but did not rebound as high as their counterparts in the effort < reward condition. The rsFCs in NS group associated with these ratings were altered. The altered rsFCs in NS group involved regions in the prefrontal lobe, dopaminergic brain regions (ventral tegmental area, substantia nigra), hippocampus, thalamus and cerebellum. Individuals with high levels of NS manifested their reward motivation adaptation impairment as a failure of adjustment adaptively during effort-reward imbalance condition and altered rsFCs in prefrontal, dopaminergic and other brain regions.

7.
J Autism Dev Disord ; 2023 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-37395918

RESUMO

Interoception, the sense of the physiological condition of our body, is impaired in individuals with autism spectrum disorders. Evidence suggests that subclinical autistic traits are mild manifestations of autistic symptoms, present in the general population. We examined the resting-state functional connectivity (rsFC) associating with interoception and autistic traits in 62 healthy young adults. Autistic traits correlated negatively with the rsFC between the lateral ventral anterior insula and anterior cingulate cortex. Interoceptive accuracy and sensibility correlated positively with the rsFC between interoceptive brain networks and the cerebellum, supplementary motor area, and visual regions. The results suggest that a negative relationship between interoception and autistic traits is largely accounted for by both self-report measures and decreased rsFC amongst the interoceptive brain network.

8.
Psych J ; 12(5): 746-748, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37291952

RESUMO

This sequential mediation analysis study examined how the baseline effort-reward imbalance (ERI) would predict reward motivation 1 year later in 435 college students. We found that negative/disorganized schizotypal traits and anticipatory pleasure experience together mediate the prediction of ERI for reward motivation.

9.
Asian J Psychiatr ; 85: 103598, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37119684

RESUMO

OBJECTIVES: Childhood trauma (CT) has been found to increase the risk of developing schizophrenia and other psychiatric disorders. Little is known regarding the complex interplay between CT, subclinical psychotic, and affective symptoms in the general population. This cross-sectional study adopted network analysis to examine such a complex relationship. We hypothesized that CT would show strong connections with schizotypy dimensions, and the high schizotypy subgroup would show a network with higher global strength compared with the low schizotypy subgroup. METHODS: A total of 1813 college students completed a set of self-report questionnaires measuring CT, schizotypal features, bipolar traits, and depressive symptoms. The subscales of these questionnaires were used as nodes, and the partial correlations between nodes were used as edges to construct a network. Network Comparison Tests were used to investigate the differences between participants with high schizotypy and low schizotypy. An independent sample (n = 427) was used to examine the replicability of the results. RESULTS: Findings from the main dataset showed that CT was closely connected with schizotypy and motivation, after controlling for the inter-relationships between all nodes in the network. Relative to the low schizotypy subgroup, the network of the high schizotypy subgroup showed higher global strength. The two subgroups did not differ in network structure. Network analysis using the replication dataset showed comparable global strength and network structure. CONCLUSIONS: Our findings support specific links between CT and schizotypy dimensions in healthy youth populations, and such links appear to become stronger in those with high schizotypy.


Assuntos
Experiências Adversas da Infância , Esquizofrenia , Transtorno da Personalidade Esquizotípica , Adolescente , Humanos , Transtorno da Personalidade Esquizotípica/diagnóstico , Estudos Transversais , Esquizofrenia/diagnóstico , Inquéritos e Questionários
10.
Psych J ; 12(3): 452-460, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36859636

RESUMO

Major depressive disorder (MDD) is associated with deficits in emotion experience, expression and regulation. Whilst emotion regulation deficits prolong MDD, emotion expression influences symptomatic presentations, and anticipatory pleasure deficits predict recurrence risk. Profiling MDD patients from an emotion componential perspective can characterize subtypes with different clinical and functional outcomes. This study aimed to investigate emotional subtypes of MDD. A two-stage cluster analysis applied to 150 MDD patients. Clustering variables included emotion experience measured by Temporal Experience of Pleasure Scale, emotion expression measured by Toronto Alexithymia Scale, and emotion regulation measured by Emotion Regulation Questionnaire. We validated the resultant clusters by comparing their symptoms and functioning with that of 50 controls. Cluster 1 (n = 50) exhibited intact emotion experience and expression yet adopted reappraisal rather than suppression strategy, whereas Cluster 2 (n = 66) exhibited generalized emotional deficits. Cluster 3 (n = 34) exhibited emotion expression deficits and adopted both reappraisal and suppression strategies. On validation, Cluster 2 exhibited the worst, but Cluster 1 exhibited the least symptoms and social functioning impairments. Cluster 3 was intermediate among the two other subtypes. Our findings support the existence of different emotional subtypes in MDD patients, and have clinical and theoretical implications for developing future specific treatments for MDD.


Assuntos
Análise por Conglomerados , Transtorno Depressivo Maior , Emoções , Depressão , Humanos , Masculino , Feminino , Adulto Jovem , Adulto , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Transtorno Depressivo Maior/classificação , Transtorno Depressivo Maior/psicologia , Análise de Variância
11.
Front Immunol ; 14: 984816, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36761750

RESUMO

Background: Recent evidence highlights the fact that immunotherapy has significantly improved patient outcomes. CD93, as a type I transmembrane glycoprotein, was correlated with tumor-associated angiogenesis; however, how CD93 correlates with immunotherapy in stomach adenocarcinoma (STAD) remains unclear. Methods: TCGA, GTEx, GEO, TIMER2.0, HPA, TISIDB, TCIA, cBioPortal, LinkedOmics, and ImmuCellAI public databases were used to elucidate CD93 in STAD. Visualization and statistical analysis of data were performed by R (Version 4.1.3), GraphPad (Version 8.0.1), and QuPath (Version 0.3.2). Results: CD93 was highly expressed in STAD compared with adjacent normal tissues. The overexpression of CD93 was significantly correlated with a poor prognosis in STAD. There was a negative correlation between CD93 expression levels with CD93 mutation and methylation in STAD. Our results revealed that CD93 expression was positively associated with most immunosuppressive genes (including PD-1, PD-L1, CTLA-4, and LAG3), immunostimulatory genes, HLA, chemokine, and chemokine receptor proteins in STAD. Furthermore, in STAD, CD93 was noticeably associated with the abundance of multiple immune cell infiltration levels. Functional HALLMARK and KEGG term enhancement analysis of CD93 through Gene Set Enrichment Analysis was correlated with the process of the angiogenesis pathway. Subsequently, digital image analysis results by QuPath revealed that the properties of CD93+ cells were statistically significant in different regions of stomach cancer and normal stomach tissue. Finally, we utilized external databases, including GEO, TISIDB, ImmuCellAI, and TCIA, to validate that CD93 plays a key role in the immunotherapy of STAD. Conclusion: Our study reveals that CD93 is a potential oncogene and is an indicative biomarker of a worse prognosis and exerts its immunomodulatory properties and potential possibilities for immunotherapy in STAD.


Assuntos
Adenocarcinoma , Receptores de Complemento , Neoplasias Gástricas , Humanos , Adenocarcinoma/genética , Adenocarcinoma/terapia , Imunoterapia , Multiômica , Prognóstico , Neoplasias Gástricas/genética , Neoplasias Gástricas/terapia , Receptores de Complemento/genética
13.
Psych J ; 12(4): 514-523, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36517928

RESUMO

The anterior insula (AI) has the central role in coordinating attention and integrating information from multiple sensory modalities. AI dysfunction may contribute to both sensory and social impairments in autism spectrum disorder (ASD). Little is known regarding the brain mechanisms that guide multisensory integration, and how such neural activity might be affected by autistic-like symptoms in the general population. In this study, 72 healthy young adults performed an audiovisual speech synchrony judgment (SJ) task during fMRI scanning. We aimed to investigate the SJ-related brain activations and connectivity, with a focus on the AI. Compared with synchronous speech, asynchrony perception triggered stronger activations in the bilateral AI, and other frontal-cingulate-parietal regions. In contrast, synchronous perception resulted in greater involvement of the primary auditory and visual areas, indicating multisensory validation and fusion. Moreover, the AI demonstrated a stronger connection with the anterior cingulate gyrus (ACC) in the audiovisual asynchronous (vs. synchronous) condition. To facilitate asynchrony detection, the AI may integrate auditory and visual speech stimuli, and generate a control signal to the ACC that further supports conflict-resolving and response selection. Correlation analysis, however, suggested that audiovisual synchrony perception and its related AI activation and connectivity did not significantly vary with different levels of autistic traits. These findings provide novel evidence for the neural mechanisms underlying multisensory temporal processing in healthy people. Future research should examine whether such findings would be extended to ASD patients.


Assuntos
Transtorno do Espectro Autista , Transtorno Autístico , Adulto Jovem , Humanos , Percepção Auditiva/fisiologia , Percepção Visual/fisiologia , Fala , Estimulação Acústica , Estimulação Luminosa
14.
Psych J ; 12(2): 202-210, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36428096

RESUMO

Emotion processing and beliefs about pleasure can influence the development and severity of depressive symptoms. This cluster analysis study aimed to profile a large sample of college students using pleasure experience, emotion expression and regulation as well as beliefs about pleasure. We also aimed to validate the resultant clusters in terms of depressive symptoms. A set of checklists capturing beliefs about pleasure and the three facets of emotion processing was administered to 1028 college students. A two-stage cluster analysis was used to analyze the profile of these emotional aspects in these college students. Our results showed that a three-cluster solution best fit the data. Cluster 1 (n = 536) was characterized by moderate levels of beliefs about pleasure, pleasure experience, emotion expression, and regulation; Cluster 2 (n = 402) was characterized by generally high levels of beliefs about pleasure, pleasure experience, emotion expression, and regulation; Cluster 3 (n = 90) was characterized by relatively low levels of beliefs about pleasure, pleasure experience, emotion expression, and regulation. The three clusters differed significantly in the severity of depressive symptoms. Our findings suggest the existence of three emotional subtypes, which may be useful in early detection of youth at risk of developing depression.


Assuntos
Emoções , Prazer , Adolescente , Humanos , Emoções/fisiologia , Prazer/fisiologia , Estudantes/psicologia , Análise por Conglomerados
15.
Eur Arch Psychiatry Clin Neurosci ; 273(2): 439-445, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35637380

RESUMO

The schizotypy construct is useful for studying the effects of environmental stress on development of subclinical negative symptoms. The relationship among self-report motivation, effort-reward imbalance (ERI), and schizotypal features has seldom been studied. We aimed to examine the possible moderation effect of schizotypal traits on ERI and reward motivation. Eight-hundred-and-forty-three college students were recruited online to complete a set of self-reported measures capturing schizotypal traits, effort-reward imbalance and reward motivation, namely the Schizotypal Personality Questionnaire (SPQ), the Effort-Reward Imbalance-School Version Questionnaire (C-ERI-S) and the Motivation and Pleasure Scale-Self Report (MAP-SR). We conducted multiple linear regression to construct models to investigate the moderating effects of schizotypal traits on the relationship between ERI and reward motivation. Stressful ERI situation predicted the reduction of reward motivation. Negative schizotypal traits showed a significant negative moderating effect on the relationship between ERI and reward motivation, while positive and disorganized schizotypal traits had significant positive moderating effects. Schizotypal traits subtypes differently moderate the relationship between ERI and reward motivation. Only negative schizotypal traits and stressful ERI situation together have negative impact on reward motivation.


Assuntos
Motivação , Recompensa , Transtorno da Personalidade Esquizotípica , Feminino , Humanos , Masculino , Adulto Jovem , Análise de Regressão , Transtorno da Personalidade Esquizotípica/psicologia , Autorrelato , Inquéritos e Questionários , Estresse Psicológico
16.
Eur Arch Psychiatry Clin Neurosci ; 273(5): 1029-1039, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36305919

RESUMO

Altered social reward anticipation could be found in schizophrenia (SCZ) patients and individuals with high levels of social anhedonia (SA). However, few research investigated the putative neural processing for altered social reward anticipation in these populations on the SCZ spectrum. This study aimed to examine the underlying neural mechanisms of social reward anticipation in these populations. Twenty-three SCZ patients and 17 healthy controls (HC), 37 SA individuals and 50 respective HCs completed the Social Incentive Delay (SID) imaging task while they were undertaking MRI brain scans. We used the group contrast to examine the alterations of BOLD activation and functional connectivity (FC, psychophysiological interactions analysis). We then characterized the beta-series social brain network (SBN) based on the meta-analysis results from NeuroSynth and examined their prediction effects on real-life social network (SN) characteristics using the partial least squared regression analysis. The results showed that SCZ patients exhibited hypo-activation of the left medial frontal gyrus and the negative FCs with the left parietal regions, while individuals with SA showed the hyper-activation of the left middle frontal gyrus when anticipating social reward. For the beta-series SBNs, SCZ patients had strengthened cerebellum-temporal FCs, while SA individuals had strengthened left frontal regions FCs. However, such FCs of the SBN failed to predict the real-life SN characteristics. These preliminary findings suggested that SCZ patients and SA individuals appear to exhibit altered neural processing for social reward anticipation, and such neural activities showed a weakened association with real-life SN characteristics.


Assuntos
Esquizofrenia , Humanos , Esquizofrenia/diagnóstico por imagem , Anedonia/fisiologia , Encéfalo/diagnóstico por imagem , Recompensa , Motivação , Imageamento por Ressonância Magnética
17.
Psychiatry Res Neuroimaging ; 326: 111528, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36027707

RESUMO

Altered hub regions in brain network have been consistently reported in patients with schizophrenia. However, it is unclear whether similar altered hub regions of the brain would be exhibited in individuals with subclinical features of schizophrenia such as social anhedonia (SA). In this study, we examined the hub regions of resting-state social brain network (SBN) of 35 participants with SA and 50 healthy controls (HC). We further examined the prediction effect of hub-connected FCs with SBN on the real-life social network characteristics. Our findings showed that the right amygdala, left temporal lobe and right media superior frontal gyrus were the hub regions of SBN both in SA and HC groups. In the SA group, the left temporal lobe connected functional connectivity (FC) did not predict social network characteristics, while the other FCs strengthened the association with social network characteristics. These findings were replicated in an independent sample of 33 SA and 32 HC. These findings suggested that the left temporal lobe as one of the hub regions of SBN exhibited the abnormality of their connected FCs in the association with social network characteristics in individuals with SA.

18.
Schizophr Res ; 248: 131-139, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36037646

RESUMO

BACKGROUND: Negative symptoms are core symptom of schizophrenia, and many previous research studied the latent structure of negative symptoms based on a single measurement scale. Applying two second-generation negative symptom scales to the same sample can address measurement-invariance of latent structure. METHODS: Three-hundred-and-five schizophrenia patients were assessed using the CAINS and the BNSS. Confirmatory Factor Analysis (CFA) tested four competing factor-models: (1) a 1-factor model; (2) a 2-factor model comprising the motivation and pleasure (MAP) domain and the diminished expression (EXP) domain; (3) a 5-factor model comprising anhedonia, avolition, asociality, blunted affect and alogia; (4) a hierarchical model comprising the "first-order" 5-domain factors and the "second-order" MAP & EXP factors. RESULTS: The CFA results for the data of the CAINS showed that the 2-factor model had the best data fit over the other competing models. The CFA using the BNSS data in the same sample also supported the superiority of the 2-factor model. Lastly, after combining the items of the BNSS and CAINS together in the same sample for CFA, the 2-factor model prevailed over the other competing models. CONCLUSIONS: The 2-factor model appears to be measurement-invariant latent structure of negative symptoms. The novel method of combining the items of the CAINS and BNSS might have circumvented the possible imperfect construct of a single scale. Our findings support the MAP and EXP factors as the latent structure for negative symptoms.


Assuntos
Esquizofrenia , Humanos , Esquizofrenia/diagnóstico , Escalas de Graduação Psiquiátrica , Reprodutibilidade dos Testes , Anedonia , Análise Fatorial , Psicometria
19.
Rev Sci Instrum ; 93(6): 063901, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35778034

RESUMO

There is an ever increasing interest in studying dynamic-pressure dependent phenomena utilizing dynamic Diamond Anvil Cells (dDACs), devices capable of a highly controlled rate of compression. Here, we characterize and compare the compression rate of dDACs in which the compression is actuated via three different methods: (1) stepper motor (S-dDAC), (2) gas membrane (M-dDAC), and (3) piezoactuator (P-dDAC). The compression rates of these different types of dDAC were determined solely on millisecond time-resolved R1-line fluorescence of a ruby sphere located within the sample chamber. Furthermore, these different dynamic compression-techniques have been described and characterized over a broad temperature and pressure range from 10 to 300 K and 0-50 GPa. At room temperature, piezoactuation (P-dDAC) has a clear advantage in controlled extremely fast compression, having recorded a compression rate of ∼7 TPa/s, which is also found to be primarily influenced by the charging time of the piezostack. At 40-250 K, gas membranes (M-dDAC) have also been found to generate rapid compression of ∼0.5-3 TPa/s and are readily interfaced with moderate cryogenic and ultrahigh vacuum conditions. Approaching more extreme cryogenic conditions (<10 K), a stepper motor driven lever arm (S-dDAC) offers a solution for high-precision moderate compression rates in a regime where P-dDACs and M-dDACs can become difficult to incorporate. The results of this paper demonstrate the applicability of different dynamic compression techniques, and when applied, they can offer us new insights into matter's response to strain, which is highly relevant to physics, geoscience, and chemistry.

20.
Phys Rev Lett ; 128(21): 215702, 2022 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-35687440

RESUMO

Through a series of x-ray diffraction, optical spectroscopy diamond anvil cell experiments, combined with density functional theory calculations, we explore the dense CH_{4}-H_{2} system. We find that pressures as low as 4.8 GPa can stabilize CH_{4}(H_{2})_{2} and (CH_{4})_{2}H_{2}, with the latter exhibiting extreme hardening of the intramolecular vibrational mode of H_{2} units within the structure. On further compression, a unique structural composition, (CH_{4})_{3}(H_{2})_{25}, emerges. This novel structure holds a vast amount of molecular hydrogen and represents the first compound to surpass 50 wt % H_{2}. These compounds, stabilized by nuclear quantum effects, persist over a broad pressure regime, exceeding 160 GPa.

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