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1.
JAMA Netw Open ; 7(5): e2410546, 2024 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-38700868

RESUMEN

This cross-sectional study assesses the adequacy of gender-neutral public restrooms and examines the association of public restroom­related stress with mental health among gender-diverse individuals in China.


Asunto(s)
Salud Mental , Humanos , China/epidemiología , Femenino , Masculino , Salud Mental/estadística & datos numéricos , Adulto , Adulto Joven , Adolescente , Estudios Transversales , Minorías Sexuales y de Género/estadística & datos numéricos , Minorías Sexuales y de Género/psicología
2.
Cells ; 13(8)2024 Apr 19.
Artículo en Inglés | MEDLINE | ID: mdl-38667324

RESUMEN

After exposure to cold stress, animals enhance the production of beige adipocytes and expedite thermogenesis, leading to improved metabolic health. Although brown adipose tissue in rodents is primarily induced by ß3-adrenergic receptor (ADRB3) stimulation, the activation of major ß-adrenergic receptors (ADRBs) in pigs has been a topic of debate. To address this, we developed overexpression vectors for ADRB1, ADRB2, and ADRB3 and silenced the expression of these receptors to observe their effects on the adipogenic differentiation stages of porcine preadipocytes. Our investigation revealed that cold stress triggers the transformation of subcutaneous white adipose tissue to beige adipose tissue in pigs by modulating adrenergic receptor levels. Meanwhile, we found that ADRB3 promotes the transformation of white adipocytes into beige adipocytes. Notably, ADRB3 enhances the expression of beige adipose tissue marker genes, consequently influencing cellular respiration and metabolism by regulating lipolysis and mitochondrial expression. Therefore, ADRB3 may serve as a pivotal gene in animal husbandry and contribute to the improvement of cold intolerance in piglets.


Asunto(s)
Adipocitos Beige , Frío , Receptores Adrenérgicos beta 3 , Animales , Receptores Adrenérgicos beta 3/metabolismo , Receptores Adrenérgicos beta 3/genética , Adipocitos Beige/metabolismo , Porcinos , Adipogénesis/genética , Lipólisis , Termogénesis/genética , Diferenciación Celular , Mitocondrias/metabolismo
3.
Chem Mater ; 36(6): 2898-2906, 2024 Mar 26.
Artículo en Inglés | MEDLINE | ID: mdl-38558914

RESUMEN

Grain boundaries (GBs) play an important role in determining the optoelectronic properties of perovskites, requiring an atomistic understanding of the underlying mechanisms. Strain engineering has recently been employed in perovskite solar cells, providing a novel perspective on the role of perovskite GBs. Here, we theoretically investigate the impact of axial strain on the geometric and electronic properties of a common CsPbBr3 GB. We develop a machine learning force field and perform ab initio calculations to analyze the behavior of GB models with different axial strains on a nanosecond time scale. Our results demonstrate that compressing the GB efficiently suppresses structural fluctuations and eliminates trap states originating from large-scale distortions. The GB becomes more amorphous under compressive strain, which makes the relationship between the electronic structure and axial strain nonmonotonic. These results can help clarify the conflicts in perovskite GB experiments.

4.
Ecotoxicol Environ Saf ; 277: 116357, 2024 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-38677073

RESUMEN

Polystyrene microplastics (PS-MPs) are new types of environmental pollutant that have garnered significant attention in recent years since they were found to cause damage to the human respiratory system when they are inhaled. The pulmonary fibrosis is one of the serious consequences of PS-MPs inhalation. However, the impact and underlying mechanisms of PS-MPs on pulmonary fibrosis are not clear. In this study, we studied the potential lung toxicity and PS-MPs-developed pulmonary fibrosis by long-term intranasal inhalation of PS-MPs. The results showed that after exposing to the PS-MPs, the lungs of model mouse had different levels of damage and fibrosis. Meanwhile, exposing to the PS-MPs resulted in a markedly decrease in glutathione (GSH), an increase in malondialdehyde (MDA), and iron overload in the lung tissue of mice and alveolar epithelial cells (AECs). These findings suggested the occurrence of PS-MP-induced ferroptosis. Inhibitor of ferroptosis (Fer-1) had alleviated the PS-MPs-induced ferroptosis. Mechanically, PS-MPs triggered cell ferroptosis and promoted the development of pulmonary fibrosis via activating the cGAS/STING signaling pathway. Inhibition of cGAS/STING with G150/H151 attenuated pulmonary fibrosis after PS-MPs exposure. Together, these data provided novel mechanistic insights of PS-MPs-induced pulmonary fibrosis and a potential therapeutic paradigm.


Asunto(s)
Células Epiteliales Alveolares , Ferroptosis , Proteínas de la Membrana , Microplásticos , Poliestirenos , Fibrosis Pulmonar , Transducción de Señal , Ferroptosis/efectos de los fármacos , Animales , Fibrosis Pulmonar/inducido químicamente , Fibrosis Pulmonar/patología , Poliestirenos/toxicidad , Ratones , Transducción de Señal/efectos de los fármacos , Microplásticos/toxicidad , Células Epiteliales Alveolares/efectos de los fármacos , Células Epiteliales Alveolares/patología , Proteínas de la Membrana/metabolismo , Masculino , Ratones Endogámicos C57BL
5.
Phytomedicine ; 129: 155552, 2024 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-38552378

RESUMEN

BACKGROUND: Studies have shown that phenylethanoid glycosides (PhGs) have multiple pharmacological effects such as anti-inflammatory, hepatoprotective or neuroprotective functions, whereas their anti-tumor effects are rarely studied. Tubuloside B (Tub B) is a PhG isolated from Cistanche deserticola, a traditional Chinese medicine. To date, there is a lack of comprehensive research regarding the biological activity of Tub B. PURPOSE: The subject of the current study was to investigate the anti-hepatocellular carcinoma (HCC) cell activity and the underlying mechanism of Tub B. METHODS: We evaluated the in vitro anti-migratory effect of Tub B by scratch and transwell assays. RNA-seq was employed to identify the differential genes by Tub B. Besides, the functional mechanism of Tub B was investigated by distinct molecular biology techniques including immunofluorescent staining, quantitative PCR, as well as western blot analysis. Subsequently, we utilized Hep3B cells for in vivo metastasis assays through spleen injection and evaluated the anti-migratory effect of Tub B in hepatocellular carcinoma (HCC). RESULTS: Tub B exhibited in vitro and in vivo inhibition of HCC cell migration. Tub B decreased the expression of transcriptional target genes downstream of the Hippo pathway, including CTGF, CYR61, and N-cadherin as determined by RNA-seq. Furthermore, mechanistic studies confirmed that Tub B increased phosphorylation of YAP at S127, which contributes to YAP cytoplasmic localization. Additionally, overexpression of YAP abrogated Tub B-induced inhibition of HCC migration and the mRNA levels of CTGF, CYR61, and N-cadherin. CONCLUSIONS: Taken together, these results illustrated that Tub B demonstrated great potential in inhibiting migration of HCC, and a portion of its impact can be attributed to the modulation of the Hippo-YAP pathway.

6.
Cell Commun Signal ; 22(1): 164, 2024 03 06.
Artículo en Inglés | MEDLINE | ID: mdl-38448900

RESUMEN

Pancreatic neuroendocrine tumors (PanNETs), though uncommon, have a high likelihood of spreading to other body parts. Previously, the genetic diversity and evolutionary patterns in metastatic PanNETs were not well understood. To investigate this, we performed multiregion sampling whole-exome sequencing (MRS-WES) on samples from 10 patients who had not received prior treatment for metastatic PanNETs. This included 29 primary tumor samples, 31 lymph node metastases, and 15 liver metastases. We used the MSK-MET dataset for survival analysis and validation of our findings. Our research indicates that mutations in the MEN1/DAXX genes might trigger the early stages of PanNET development. We categorized the patients based on the presence (MEN1/DAXXmut, n = 7) or absence (MEN1/DAXXwild, n = 3) of these mutations. Notable differences were observed between the two groups in terms of genetic alterations and clinically relevant mutations, confirmed using the MSK-MET dataset. Notably, patients with mutations in MEN1/DAXX/ATRX genes had a significantly longer median overall survival compared to those without these mutations (median not reached vs. 43.63 months, p = 0.047). Multiplex immunohistochemistry (mIHC) analysis showed a more prominent immunosuppressive environment in metastatic tumors, especially in patients with MEN1/DAXX mutations. These findings imply that MEN1/DAXX mutations lead PanNETs through a unique evolutionary path. The disease's progression pattern indicates that PanNETs can spread early, even before clinical detection, highlighting the importance of identifying biomarkers related to metastasis to guide personalized treatment strategies.


Asunto(s)
Neoplasias Hepáticas , Tumores Neuroendocrinos , Neoplasias Pancreáticas , Humanos , Secuenciación del Exoma , Tumores Neuroendocrinos/genética , Genómica , Neoplasias Hepáticas/genética , Neoplasias Pancreáticas/genética , Microambiente Tumoral
8.
J Phys Chem Lett ; 15(13): 3611-3618, 2024 Apr 04.
Artículo en Inglés | MEDLINE | ID: mdl-38530095

RESUMEN

Further improving the activity and selectivity of photocatalytic CO2 reduction remains a challenge. Herein, we propose a new strategy for synergistically promoting photocatalytic CO2 reduction by combining two-dimensional (2D) ferroelectric polarization and single-atom catalysis. Our calculations showed that the ferroelectric polarization of CuBiP2Se6 provides the internal driving force for the separation and migration of photogenerated carriers, which provides a prerequisite for enhancing the photocatalytic efficiency. In addition, the introduction of single Ag atoms can act as an electron reservoir to significantly modify the bonding configurations on the surface through proper static electron transfer, thus effectively promoting the adsorption and activation of CO2 molecules. More importantly, we found that switching the ferroelectric polarization can synergistically optimize the limiting potential as well as control the final products. This study provides a new approach for enhancing the catalytic activity and selectivity of photocatalytic CO2 reduction.

9.
J Phys Chem Lett ; 15(10): 2867-2875, 2024 Mar 14.
Artículo en Inglés | MEDLINE | ID: mdl-38446846

RESUMEN

The rapid recombination of photogenerated carriers heavily restricts the photocatalytic efficiency. Here, we propose a new strategy to improve catalytic efficiency based on the ferroelectric van der Waals heterostructure (CuBiP2Se6/C2N). Combining density functional theory and the nonadiabatic molecular dynamics (NAMD) method, we have systematically analyzed the ground-state properties and carrier dynamics images in the CuBiP2Se6/C2N heterostructure. Our calculations showed that the ferroelectric polarization of CuBiP2Se6 provides the internal driving force for the photogenerated carriers separation. NAMD results demonstrate that the excited-state carrier transfer and recombination processes in the CuBiP2Se6/C2N are consistent with a type II mechanism. Meanwhile, constructing the ferroelectric heterostructure can effectively prolong the carrier lifetime, from ∼65.98 to ∼124.54 ps. Moreover, the high quantum efficiency and tunable band edge positions mean that the CuBiP2Se6/C2N heterostructure is an excellent potential candidate material for photocatalytic water splitting.

10.
Small ; : e2310530, 2024 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-38317526

RESUMEN

Rechargeable aprotic Li-CO2 batteries have aroused worldwide interest owing to their environmentally friendly CO2 fixation ability and ultra-high specific energy density. However, its practical applications are impeded by the sluggish reaction kinetics and discharge product accumulation during cycling. Herein, a flexible composite electrode comprising CoSe2 nanoparticles embedded in 3D carbonized melamine foam (CoSe2 /CMF) for Li-CO2 batteries is reported. The abundant CoSe2 clusters can not only facilitate CO2 reduction/evolution kinetics but also serve as Li2 CO3 nucleation sites for homogeneous discharge product growth. The CoSe2 /CMF-based Li-CO2 battery exhibits a large initial discharge capacity as high as 5.62 mAh cm-2 at 0.05 mA cm-2 , a remarkably small voltage gap of 0.72 V, and an ultrahigh energy efficiency of 85.9% at 0.01 mA cm-2 , surpassing most of the noble metal-based catalysts. Meanwhile, the battery demonstrates excellent cycling stability of 1620 h (162 cycles) at 0.02 mA cm-2 with an average overpotential of 0.98 V and energy efficiency of 85.4%. Theoretical investigations suggest that this outstanding performance is attributed to the suitable CO2 /Li adsorption and low Li2 CO3 decomposition energy. Moreover, flexible Li-CO2 pouch cell with CoSe2 /CMF cathode displays stable power output under different bending deformations, showing promising potential in wearable electronic devices.

11.
J Cell Mol Med ; 28(3): e18103, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38217314

RESUMEN

Porcine reproductive and respiratory syndrome (PRRS) is a respiratory disease in pigs that causes severe economic losses. Currently, live PRRSV vaccines are commonly used but fail to prevent PRRS outbreaks and reinfection. Inactivated PRRSV vaccines have poor immunogenicity, making PRRSV a significant threat to swine health globally. Therefore, there is an urgent need to develop an effective PRRSV vaccine. This study used immunoinformatics to predict, screen, design and construct a candidate vaccine that fused B-cell epitopes, CTL- and HTL-dominant protective epitopes of PRRSV strain's GP3 and GP5 proteins. The study identified 12 B-cell epitopes, 6 CTL epitopes and 5 HTL epitopes of GP3 and GP5 proteins. The candidate vaccine was constructed with 50S ribosomal protein L7/L1 molecular adjuvant, which has antigenicity, solubility, stability, non-allergenicity and a high affinity for its target receptor, TLR-3. The C-ImmSim immunostimulation results showed significant increases in cellular and humoral responses (B cells and T cells) and production of TGF-ß, IL-2, IL-10, IFN-γ and IL-12. The constructed vaccine was stable and immunogenic, and it can effectively induce strong T-cell and B-cell immune responses against PRRSV. Therefore, it is a promising candidate vaccine for controlling and preventing PRRSV outbreaks.


Asunto(s)
Síndrome Respiratorio y de la Reproducción Porcina , Virus del Síndrome Respiratorio y Reproductivo Porcino , Vacunas , Animales , Porcinos , Epítopos de Linfocito B , Inmunoinformática , Anticuerpos Antivirales
12.
Psychol Trauma ; 16(Suppl 1): S63-S71, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-37650803

RESUMEN

OBJECTIVE: Childhood trauma has been identified as a risk factor for self-injurious thoughts and behaviors (STBs), but the roles of different types of childhood trauma have not been clarified. The current study aimed to explore the association between different childhood trauma experiences and STB profiles. METHOD: The current study utilized data from a cross-sectional survey of 89,281 Chinese university and college students (Mage = 19.6). Participants were classified into one of six STBs groups, including individuals who are not suicidal or having nonsuicidal self-injury (NS) behavior, individuals with suicidal ideation (SI), individuals with nonsuicidal self-injury (NSSI) behavior, individuals with suicide attempt (SA), individuals with both NSSI and SI (NSSI + SI) and individuals with both NSSI and SA (NSSI + SA). Several multinomial logistic regressions were performed. RESULTS: The individuals reporting more emotional abuse experiences are significantly more likely to report higher-risk STB profiles (OR =1.06-1.64). Emotional neglect is also a significant factor predicting higher STB risk compared to NS and SI groups (OR = 1.02-1.08). Mixed findings were found for physical neglect and sexual abuse, as they show different directions of risk-predicting effects in different STB groups. Physical abuse did not significantly predict STBs. CONCLUSIONS: Our results indicate that exposure to childhood emotional abuse increase the risk for all types of STBs, which calls for special attention in future suicide prevention and intervention programs. Our findings further imply possible roles for different subtypes of traumatic experiences to trigger different SBTs, which warrant future exploration. (PsycInfo Database Record (c) 2024 APA, all rights reserved).


Asunto(s)
Experiencias Adversas de la Infancia , Conducta Autodestructiva , Humanos , Adulto Joven , Adulto , Estudios Transversales , Intento de Suicidio/psicología , Conducta Autodestructiva/epidemiología , Conducta Autodestructiva/etiología , Conducta Autodestructiva/psicología , Ideación Suicida , Factores de Riesgo
13.
Cancer Rep (Hoboken) ; 7(1): e1940, 2024 01.
Artículo en Inglés | MEDLINE | ID: mdl-38030392

RESUMEN

BACKGROUND: Mesonephric carcinoma (MC) is a very rare tumor with less than 70 cases had been reported. The rarity of MC has restricted its research, resulting in the lack of published guidelines. OBJECTIVE: To summarize the characteristics and construct an external-validated nomogram to predict the survival of MC patients. METHOD: Sixty-four qualified patients derived from the Surveillance, Epidemiology, and End Results Plus database, and one patient from the Guangzhou Red Cross Hospital were enrolled. The entire cohort was randomly divided into a development (70%) and a validation cohort (30%). The Kaplan-Meier method and univariate and multivariate Cox regression analyses were applied. Two nomograms were established to predict the 3-to-8-year survival probability of MC patients, which were evaluated by C-index, ROC curves, DCA curves, and calibration plots. RESULTS: The average survival time of MC patients was 84.22 ± 50.66 months. No significant difference was shown among different groups of race, primary site, tumor differentiated grade, and FIGO stages, while different SEER stages did distinguish patients' survival time, which indicated that the SEER stage standards might be a better staging system in the MC patients than FIGO stage (p = .0835). Additional survival analyses showed that MC patients benefited from shorter waiting times to begin treatment, accepting surgery, regional lymph node examination, radiotherapy, and chemotherapy. Two nomograms were established, both of which got satisfied scores in C-index, ROC curves, DCA curves, and calibration plots. CONCLUSION: Sufficient regional lymph nodes examined, and applying radiotherapy in high-risk patients are recommended in MC patients. Nomograms established in the present study had good predicting and discriminating capabilities, which would be helpful in patients' individual risk estimation, management, counseling, and follow-up.


Asunto(s)
Carcinoma , Nomogramas , Humanos , Bases de Datos Factuales , Ganglios Linfáticos
14.
Chem Biol Interact ; 387: 110818, 2024 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-38000455

RESUMEN

Hyperglycaemia causes impairment of osteogenic differentiation and accelerates stem cell senescence, resulting in weakened osteogenesis and disordered bone metabolism. Phytic acid (PA) is an antioxidant that is reportedly beneficial to bone homeostasis. The present study aims to clarify how PA affects the osteogenic capacity and cellular senescence of bone marrow mesenchymal stem cells (BMSCs) exposed to high-glucose environments, as well as the potential molecular mechanisms. Our results indicate that osteogenic differentiation in BMSCs cultivated in high-glucose conditions is enhanced by PA, as evidenced by increased alkaline phosphatase activity and staining, Alizarin Red S staining, osteogenic marker in in vitro studies, and increased osteogenesis in animal experiments. PA also prevented high-glucose-induced senescence of BMSCs, as evidenced by the repression of reactive oxygen species production, senescence-associated ß-galactosidase staining, and P21 and P53 expression. Furthermore, it was found that PA rescued the high-glucose-inhibited expression of phosphorylated extracellular regulated protein kinases (p-ERK). The inhibition of ERK pathway by the specific inhibitor PD98059 blocked the PA-enhanced osteogenesis of BMSCs and promoted cell senescence. Our results revealed that PA enhances osteogenic differentiation and inhibits BMSC senescence in a high-glucose environment. In addition, the activation of the ERK pathway seems to mediate the beneficial effects of PA. The findings provide novel insights that could facilitate bone regeneration in patients with diabetes.


Asunto(s)
Células Madre Mesenquimatosas , Osteogénesis , Animales , Humanos , Ácido Fítico/farmacología , Ácido Fítico/metabolismo , Sistema de Señalización de MAP Quinasas , Diferenciación Celular , Glucosa/metabolismo , Células Cultivadas , Células de la Médula Ósea
16.
Genomics ; 116(1): 110765, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38113975

RESUMEN

Cholangiocarcinoma (CCA) is an aggressive bile duct malignancy with poor prognosis. To improve our understanding of the biological characteristics of CCA and develop effective therapies, appropriate preclinical models are required. Here, we established and characterized 12 novel patient-derived primary cancer cell (PDPC) models using multi-region sampling. At the genomic level of PDPCs, we observed not only commonly mutated genes, such as TP53, JAK3, and KMT2C, consistent with the reports in CCA, but also specific mutation patterns in each cell line. In addition, specific expression patterns with distinct biological functions and pathways involved were also observed in the PDPCs at the transcriptomic level. Furthermore, the drug-sensitivity results revealed that the PDPCs exhibited different responses to the six commonly used compounds. Our findings indicate that the established PDPCs can serve as novel in vitro reliable models to provide a crucial molecular basis for improving the understanding of tumorigenesis and its treatment.


Asunto(s)
Neoplasias de los Conductos Biliares , Colangiocarcinoma , Humanos , Colangiocarcinoma/metabolismo , Perfilación de la Expresión Génica/métodos , Neoplasias de los Conductos Biliares/metabolismo , Línea Celular Tumoral , Genómica , Conductos Biliares Intrahepáticos/metabolismo
17.
Mol Psychiatry ; 2023 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-38102486

RESUMEN

Parent-child transmission of suicidal behaviors has been extensively studied, but the investigation of a three-generation family suicide risk paradigm remains limited. In this study, we aimed to explore the behavioral and brain signatures of multi-generational family history of suicidal behaviors (FHoS) in preadolescents, utilizing a longitudinal design and the dataset from Adolescent Brain and Cognitive DevelopmentSM Study (ABCD Study®), which comprised 4 years of data and includes a total of 9,653 preadolescents. Our findings revealed that multi-generational FHoS was significantly associated with an increased risk of problematic behaviors and suicidal behaviors (suicide ideation and suicide attempt) in offspring. Interestingly, the problematic behaviors were further identified as a mediator in the multi-generational transmission of suicidal behaviors. Additionally, we observed alterations in brain structure within superior temporal gyrus (STG), precentral/postcentral cortex, posterior parietal cortex (PPC), cingulate cortex (CC), and planum temporale (PT), as well as disrupted functional connectivity of default mode network (DMN), ventral attention network (VAN), dorsal attention network (DAN), fronto-parietal network (FPN), and cingulo-opercular network (CON) among preadolescents with FHoS. These results provide compelling longitudinal evidence at the population level, highlighting the associations between multi-generational FHoS and maladaptive behavioral and neurodevelopmental outcomes in offspring. These findings underscore the need for early preventive measures aimed at mitigating the familial transmission of suicide risk and reducing the global burden of deaths among children and adolescents.

18.
Front Psychiatry ; 14: 1306152, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38098636

RESUMEN

Background: The previous literature has demonstrated that depression, anxiety, and stress are significant predictors of problematic social media use. However, the manifestation of problematic social media use varies, and the predictive relationship between depression, anxiety, and stress with different subgroups of problematic social media use remains unclear. The aim of this research was to evaluate latent subgroups of problematic social media use among college students and to investigate the impact of depression, anxiety, and stress on these latent subgroups. Methods: A survey was carried out among college students in China using a cross-sectional approach. A total of 955 participants were included, with a mean age of 19.50 ± 1.22 years. Participants completed questionnaires containing the Bergen Social Media Addiction Scale (BSMAS) and the Depression, Anxiety, and Stress Scale-21 (DASS-21). The study employed latent profile analysis (LPA) to investigate latent subgroups of Chinese college students with problematic social media use, and a robust three-step approach was used to develop predictive regression mixed models of depression, anxiety, and stress on latent subgroups. Results: Problematic social media use of Chinese college students can be categorized into four latent subgroups, namely, the high-risk group, the moderate-risk with pleasure group, the moderate-risk with compulsion group, and the low-risk group. The regression model showed that there was a significant difference between the high-risk group and the low-risk group on the stress scale. There was a significant difference between the moderate-risk with pleasure group and the moderate-risk with compulsion group on the depression scale. Conclusion: Problematic social media use is heterogeneous, with depression and stress being potentially key factors influencing problematic social media use. Depression would make college students more likely to be moderate-risk with compulsion problematic social media users than moderate-risk with pleasure problematic social media users, and stress would make college students more likely to be high-risk problematic social media users than low-risk problematic social media users.

19.
Rev Sci Instrum ; 94(10)2023 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-37850856

RESUMEN

Spin- and angle-resolved photoemission spectroscopy ("spin-ARPES") is a powerful technique for probing the spin degree-of-freedom in materials with nontrivial topology, magnetism, and strong correlations. Spin-ARPES faces severe experimental challenges compared to conventional ARPES attributed to the dramatically lower efficiency of its detection mechanism, making it crucial for instrumentation developments that improve the overall performance of the technique. In this paper, we demonstrate the functionality of our spin-ARPES setup based on time-of-flight spectroscopy and introduce our recent development of an electrostatic deflector mode to map out spin-resolved band structures without sample rotation. We demonstrate the functionality by presenting the spin-resolved spectra of the topological insulator Bi2Te3 and describe in detail the spectrum calibrations based on numerical simulations. By implementing the deflector mode, we minimize the need for sample rotation during measurements, hence improving the overall efficiency of experiments on small or inhomogeneous samples.

20.
Front Neurol ; 14: 1243301, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37830095

RESUMEN

Objective: To elucidate the functional role of gamma-aminobutyric acid (GABA)-ergic inhibition in suppressing epileptic brain activities such as spike-wave discharge (SWD), we recorded electroencephalogram (EEG) in knockout rats for Glutamate decarboxylase 1 (Gad1), which encodes one of the two GABA-synthesizing enzymes in mammals. We also examined how anti-epileptic drug valproate (VPA) acts on the SWDs present in Gad1 rats and affects GABA synthesis in the reticular thalamic nucleus (RTN), which is known to play an essential role in suppressing SWD. Methods: Chronic EEG recordings were performed in freely moving control rats and homozygous knockout Gad1 (-/-) rats. Buzzer tones (82 dB) were delivered to the rats during EEG monitoring to test whether acoustic stimulation could interrupt ongoing SWDs. VPA was administered orally to the rats, and the change in the number of SWDs was examined. The distribution of GABA in the RTN was examined immunohistochemically. Results: SWDs were abundant in EEG from Gad1 (-/-) rats as young as 2 months old. Although SWDs were universally detected in older rats irrespective of their Gad1 genotype, SWD symptom was most severe in Gad1 (-/-) rats. Acoustic stimulation readily interrupted ongoing SWDs irrespective of the Gad1 genotype, whereas SWDs were more resistant to interruption in Gad1 (-/-) rats. VPA treatment alleviated SWD symptoms in control rats, however, counterintuitively exacerbated the symptoms in Gad1 (-/-) rats. The immunohistochemistry results indicated that GABA immunoreactivity was significantly reduced in the somata of RTN neurons in Gad1 (-/-) rats but not in their axons targeting the thalamus. VPA treatment greatly increased GABA immunoreactivity in the RTN neurons of Gad1 (-/-) rats, which is likely due to the intact GAD2, another GAD isozyme, in these neurons. Discussion: Our results revealed two opposing roles of GABA in SWD generation: suppression and enhancement of SWD. To account for these contradictory roles, we propose a model in which GABA produced by GAD1 in the RTN neuronal somata is released extrasynaptically and mediates intra-RTN inhibition.

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