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1.
Artigo em Inglês | MEDLINE | ID: mdl-33626237

RESUMO

OBJECTIVE: No relapse risk prediction tool is currently available to guide treatment selection for multiple sclerosis (MS). Leveraging electronic health record (EHR) data readily available at the point of care, we developed a clinical tool for predicting MS relapse risk. METHODS: Using data from a clinic-based research registry and linked EHR system between 2006 and 2016, we developed models predicting relapse events from the registry in a training set (n = 1435) and tested the model performance in an independent validation set of MS patients (n = 186). This iterative process identified prior 1-year relapse history as a key predictor of future relapse but ascertaining relapse history through the labor-intensive chart review is impractical. We pursued two-stage algorithm development: (1) L1 -regularized logistic regression (LASSO) to phenotype past 1-year relapse status from contemporaneous EHR data, (2) LASSO to predict future 1-year relapse risk using imputed prior 1-year relapse status and other algorithm-selected features. RESULTS: The final model, comprising age, disease duration, and imputed prior 1-year relapse history, achieved a predictive AUC and F score of 0.707 and 0.307, respectively. The performance was significantly better than the baseline model (age, sex, race/ethnicity, and disease duration) and noninferior to a model containing actual prior 1-year relapse history. The predicted risk probability declined with disease duration and age. CONCLUSION: Our novel machine-learning algorithm predicts 1-year MS relapse with accuracy comparable to other clinical prediction tools and has applicability at the point of care. This EHR-based two-stage approach of outcome prediction may have application to neurological disease beyond MS.

2.
Per Med ; 18(2): 185-203, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33565320

RESUMO

The choice of lipid-modifying treatment is largely based on the absolute level of cardiovascular risk and baseline lipid profile. Statins are the first-line treatment for most patients requiring reduction of low-density-lipoprotein cholesterol (LDL-C) and ezetimibe and proprotein convertase subtilisin/kexin type 9 inhibitors can be added to reach LDL-C targets. Statins have some adverse effects that are somewhat predictable based on phenotypic and genetic factors. Fibrates or omega-3 fatty acids can be added if triglyceride levels remain elevated. The RNA-targeted therapeutics in development offer the possibility of selective liver targeting for specific lipoproteins such as lipoprotein(a) and long-term reduction of LDL-C with infrequent administration of a small-interfering RNA may help to overcome the problem of adherence to therapy.

4.
Cerebrovasc Dis Extra ; 11(1): 29-36, 2021 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-33601375

RESUMO

BACKGROUND: Thrombotic thrombocytopenic purpura (TTP) is a rare blood disorder resulting in organ damage including ischemic strokes. We sought to characterize the neuroimaging patterns of stroke in a large cohort of patients with immune-mediated TTP (iTTP) and determined their associations with clinical and laboratory parameters and outcomes. METHODS: We analyzed the Alabama TTP Registry who had laboratory confirmation of acute iTTP. We reviewed the neuroimaging patterns of those with ischemic stroke on MRI, clinical information, and laboratory results. Small ischemic strokes were ≤20 mm in their maximum diameter in the axial plane. Large ischemic strokes were >20 mm. Student t test, Mann-Whitney U test, and χ2 test were all used for data analysis. RESULTS: Of 108 iTTP patients, 21 had ischemic stroke on neuroimaging. The median platelet count in these patients was 12 × 109/L (interquartile range, IQR, 8.8-21 × 109/L), plasma ADAMTS13 activity 1.8 U/dL (IQR 0-4.5 U/dL), and the mean plasma level of anti-ADAMTS13 IgG was 6,595.8 U/mL (SD 3,448.9 U/mL). Comparison between patients with large ischemic strokes (n = 10) and small ischemic strokes (n = 11) revealed that patients with small stroke were older (p = 0.043) and had higher plasma levels of citrullinated histone 3 (p = 0.006) and histone/DNA complex (p = 0.014) than those with large strokes. There were no significant differences between 2 stroke groups in mortality or exacerbation. CONCLUSIONS: iTTP patients can present with large ischemic strokes and are usually younger. Further research should be performed in assessing different etiologies of iTTP-associated stroke based on neutrophil extracellular trap formation biomarkers (e.g., histone markers) seen in small ischemic stroke.

5.
J Chin Med Assoc ; 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33595989

RESUMO

BACKGROUND: Sub-total/total gastrectomy with lymph node dissection (LND) remains an effective therapeutic strategy for resectable gastric adenocarcinomas (GACs). Despite the prognostic significance of positive lymph nodes (PLNs) defined in N-status, few have appraised the impacts of negative lymph nodes (NLNs) and the percentage of NLN (= number of NLNs / number of total lymph nodes [TLNs], %), as well as the extent of TLNs to be dissected in GACs. METHODS: We retrospectively analyzed 62 GAC patients (mean age of 67.1 years; 41 men) undergoing primary sub-total/total gastrectomy from a single institute. Candidate variables, including the number of NLNs (≤9 and >9) and the percentage of NLN (≤37.5, 37.5-80.6 and>80.6, %), were evaluated to determine their prognostic impacts and hazard ratios (HRs). RESULTS: Under the multivariate Cox proportional-hazards regression model, tumor length exceeding 4 cm (p=0.017; HR=2.828), perineural invasion (p=0.037; HR=3.182) and lower percentage of NLN (p=0.016 and p=0.060; HRs=1.000, 0.327 and 0.333 for subgroups ≤37.5, 37.5-80.6 and>80.6, respectively) were three independent predictors with elevated HRs for poor prognosis. GAC patients with the percentage of NLN>80.6 were highly related to those with NLNs>9 (p<0.001), and GAC patients with NLNs>9 were highly related to those with TLNs>15 (p<0.001), respectively. For all 62 GAC or 42 N(+) GAC patients, those who underwent LND with TLNs>15 tended to have more PLNs (p=0.018, p=0.003) and more NLNs (p<0.001, p=0.029) than did those with TLNs≤15. Among the 42 GAC patients with TLNs>15, a lower percentage of NLN (p=0.026 and p=0.015; HRs=1.000, 0.272 and 0.180 for subgroups ≤37.5, 37.5-80.6 and>80.6, respectively) remained an independent predictor of poor prognosis. CONCLUSION: The percentage of NLN could predict the prognosis of GAC patients properly. However, an accurate percentage of NLN needs a minimal requirement of TLNs>15 to detect an adequate number of PLNs and sufficient number of NLNs.

6.
J Cell Physiol ; 2021 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-33580514

RESUMO

AAA domain containing 3A (ATAD3A) is a nucleus-encoded mitochondrial protein with vital function in communication between endoplasmic reticulum (ER) and mitochondria which is participated in cancer metastasis. Here we show that elevated ATAD3A expression is clinically associated with poor 5-year disease-free survival in patients with colorectal cancer (CRC), especially high-risk CRC patients who received adjuvant chemotherapy. Our results indicated ATAD3A is significantly upregulated to reduce chemotherapy-induced cancer cell death. We found that knockdown of ATAD3A leads to dysregulation in protein processing for inducing ER stress by RNA sequencing (RNA-seq). In response to chemotherapy-induced ER stress, ATAD3A interacts with elevated GRP78 protein to assist protein folding and alleviate ER stress for cancer cell survival. This reduction of ER stress leads to reduce the surface exposure of calreticulin, which is the initiator of immunogenic cell death and antitumor immunity. However, silencing of ATAD3A enhances cell death, triggers the feasibility of chemotherapy-induced ER stress for antitumor immunity, increases infiltration of T lymphocytes and delays tumor regrowth in vitro and in vivo. Clinically, CRC patients with less ATAD3A have high density of CD45+ intratumoral infiltrating lymphocytes (TILs) and memory CD45RO+ TILs. Taken together, our results suggest that pharmacologic targeting to ATAD3A might be a potential therapeutic strategy to enhance antitumor immunity for CRC patients who received adjuvant chemotherapy.

7.
PLoS One ; 16(2): e0245150, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33539356

RESUMO

Rapid modernization in China has impacted the daily lives and health of women, including a rise in obesity. However, little is known about the impact of menopausal status, behavior, and psychosocial factors on the risk of obesity for rural women in China. The aim of this study is to identify risk factors, including demographic information (education, family history of T2DM, menopausal status), obesity-related behavior, and psychosocial factors associated with overweight/general obesity and abdominal obesity. In a cross-sectional study design, participants had their weight, height, and waist circumference measured and completed questionnaires regarding family demographics, obesity-related health behaviors (physical activity, diet, sleep), and psychosocial information (stress, social support, and self-efficacy related to physical activity and healthy diet). A total of 646 women were included in this study; 46.6% were overweight/generally obese, and 48% had abdominal obesity. Postmenopausal women had a higher prevalence of general and central obesity. Regular physical activity decreased the risk for overweight/general obesity and abdominal obesity (OR = .41 and .31, respectively, p = .04) in premenopausal women. Postmenopausal women who had not breastfed their infants and reported moderate/high-stress had a higher risk for overweight/general obesity (OR = 3.93, and 2, respectively) and those who reported less than 6 hours of sleep per day increased their risk for abdominal obesity (OR = 2.08). Different factors associated with obesity were found in Chinese women, depending on menopausal status. Future studies should examine the impact of menopause on a woman's risk for obesity, as well as develop tailored interventions to improve health, well-being and reduce the risk of obesity.

8.
Eur J Clin Invest ; : e13506, 2021 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-33529347

RESUMO

BACKGROUND: Patients with functional dyspepsia (FD) are more likely to have persistent depression, yet whether depression and antidepressant treatments are associated with subsequent risk of FD remain unclear. METHODS: Using population-based insurance administrative data of Taiwan, an 11-year historic cohort study was assembled, comparing cases aged 18 and above with the diagnosis of depressive disorder, to a propensity score-matched sample of adults without depression. Incident FD as a primary diagnosis was ascertained. Hazard ratios of FD were calculated using Cox regression models by age, gender, other comorbidities, nonsteroidal anti-inflammatory medications, antidepressants and antidiabetic agents. RESULTS: A total of 20,197 people with depressive disorder and 20,197 propensity score-matched comparisons without depression were followed up. The incidence of FD was 1.7-fold greater in the depressive cohort than in comparisons (12.9 versus 7.57 per 1000 person-years), with an adjusted hazard ratio (aHR) of 2.16 (95% confidence interval (CI) 1.93~2.41). Increased risks were significant regardless of comorbidities or medication uses, the highest in the untreated depression group compared to the group without depression, with an aHR of 2.51(95% CI 2.15~2.93). CONCLUSIONS: This population-based study showed that patients with depressive disorder are at elevated risk of FD. Antidepressant treatment could reduce the risk of FD.

9.
Hu Li Za Zhi ; 68(1): 54-63, 2021 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-33521919

RESUMO

BACKGROUND: Failure to follow the "Five Rights" and interruptions during medication administration are the two most common factors underlying nurse-related medication errors. PURPOSE: This study was designed to examine the effectiveness in terms of improving nurses' medication administration self-efficacy and recognition of medication errors of an online objective structured video examination (OSVE) intervention focused on the "Five Rights" and "management of interruptions during medication administration". METHODS: A quasi-experimental pretest-posttest research design with a respondent-driven sampling method was employed. One hundred and twelve nurses finished the online survey. Instruments included the self-efficacy of medication administration questionnaire and four online medication error OSVEs addressing the issue of medication error recognition. The intervention was an acute medication behavior OSVE. Paired t-tests were used to assess the pre-test / post-test differences between variables. RESULTS: The mean age of the 112 survey respondents was 27.21 years, and the mean years of working experience was 4.67. The mean self-efficacy of medication administration score, which was 38.88 (SD = 4.45) at baseline, increased significantly to 41.69 (SD = 4.58) at post-test (t = 7.11, p < .001). Similarly, the mean score for recognition of medication errors was 10.71 (SD = 7.16) at pre-test and significantly higher (15.32; SD = 4.94) at post-test (t = 5.90, p < .001). CONCLUSIONS / IMPLICATIONS FOR PRACTICE: The online OSVE may be used to improve the recognition of medication errors and self-efficacy of medication administration in nurses. Future research is needed to examine the effect of this intervention in enhancing the safety of medication administration in actual clinical practice settings.


Assuntos
Erros de Medicação , Autoeficácia , Adulto , Humanos , Enfermeiras e Enfermeiros , Inquéritos e Questionários
10.
Abdom Radiol (NY) ; 2021 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-33388803

RESUMO

OBJECTIVES: The objectives of this study were to determine the primary technique effectiveness (PTE), to compare the complete response and local recurrence rates between conspicuous and inconspicuous tumors using single and switching electrodes of real-time virtual sonography (RVS)-assisted radiofrequency ablation (RFA) in conspicuous and inconspicuous hepatic tumors under conventional ultrasonography (US). SUBJECTS AND METHOD: We compared the complete ablation of inconspicuous tumors with and without anatomical landmark (N = 54) with conspicuous liver tumors (N = 272). Conventional US imaging was done initially, and then these images were fused with CT or MRI arterial-venous-wash-out cross-sectional studies and synchronized with real-time US images. RESULTS: RVS-assisted RFA was technically feasible in all patients. The PTE rate after the first ablation was 94% (245/261) for conspicuous tumors, 88% (7/8) in inconspicuous tumors with landmark, and 78% (36/46) in inconspicuous tumors without landmark. The complete response (p = 0.1912 vs. p = 0.4776) and local recurrence rate (p = 0.1557 vs. p = 0.7982) were comparable in conspicuous tumors of both HCC and liver metastasis group when single or multiple switching was used. The cumulative local recurrence in the conspicuous and inconspicuous tumors of the HCC group (p = 0.9999) was almost parallel after 12 (10% vs. 4%) and 24 (13% vs. 4%) months of follow-up. In the liver metastasis group, the cumulative local recurrence for conspicuous tumors (p = 0.9564) was nearly equal after 12 and 24 months of monitoring (24% vs. 27%) while no recurrence was incurred for the inconspicuous tumors. CONCLUSION: RVS-assisted RFA is an effective tool for the treatment of conspicuous and inconspicuous HCC and hepatic metastasis.

11.
Artigo em Inglês | MEDLINE | ID: mdl-33479721

RESUMO

OBJECTIVE: To evaluate the efficacy of ixekizumab (IXE), a monoclonal antibody selectively targeting interleukin-17A, in patients with inadequate response to one or two TNF inhibitors (TNFi). METHODS: A phase 3 study (SPIRIT-P2; NCT02349295) randomized patients with PsA with inadequate response or intolerance to one or two TNFi to receive 80-mg IXE every 2 weeks (n = 123) or every 4 weeks (n = 122) after a 160-mg starting dose or placebo (PBO; n = 118) through week 24. This post hoc analysis used data from inadequate responders to one or two TNFi, measuring the percentage achieving: ≥50% improvement in ACR response criteria (ACR50) and 100% improvement from baseline in the Psoriasis Area and Severity Index (PASI 100), ACR50, improvement in HAQ-Disability Index (HAQ-DI) ≥0.35, minimal disease activity (MDA), European League Against Rheumatism (EULAR) Good Response Criteria [improvement in Disease Activity Score 28 CRP (DAS28-CRP) >1.2], and Disease Activity in PsA (DAPSA) ≤14. RESULTS: There were no significant differences in baseline characteristics between inadequate responders to one and two TNFi. At week 24, significantly more patients irrespective of previous TNFi experience receiving IXE than PBO achieved ACR50, HAQ-DI ≥0.35 improvement, MDA, EULAR good response, and DAPSA ≤14, and significantly more patients with inadequate response to one TNFi receiving IXE than PBO achieved ACR50 and PASI 100. Improvement persisted in all measures through week 52. CONCLUSION: IXE improved the signs and symptoms of PsA in a population of difficult-to-treat patients with inadequate response to one or two TNFi.

12.
Mol Cancer Res ; 2021 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-33500360

RESUMO

Several master transcription factors (TF) can activate the epithelial-to-mesenchymal transition (EMT). However, their individual and combinatorial contributions to EMT in breast cancer are not defined. We show that overexpression of EMT-TFs individually in epithelial cells upregulated endogenous SNAI2, ZEB1/2, TCF4, and TWIST1/2 as a result of positive feedback mediated in part by suppression of their negative regulator miRNAs miR200s/203/205. We identified TCF4 as a potential new target of miR200s. Expression of ZEB1/2 strongly correlated with the mesenchymal phenotype in breast cancer cells, with the CD24-/CD44+ stemness profile, and with lower expression of core epithelial genes in human breast tumors. Knockdown of EMT-TFs identified the key role of ZEB1 and its functional cooperation with other EMT-TFs in the maintenance of the mesenchymal state. Inducible ZEB1+2 knockdown in xenograft models inhibited pulmonary metastasis, emphasizing their critical role in dissemination from primary site and in extravasation. However, ZEB1+2 depletion one-week after intravenous injection did not inhibit lung colonization, suggesting that ZEB1/2 and EMT are not essential for macrometastatic outgrowth. These results provide strong evidence that EMT is orchestrated by coordinated expression of several EMT-TFs and establish ZEB1 as a key master regulator of EMT and metastasis in breast cancer. IMPLICATIONS: The EMT program is orchestrated by coordinated expression of multiple EMT transcription factors, whereas ZEB1 integrates the EMT master regulatory network and plays the major role in promoting EMT and metastasis.

13.
Psychiatry Res ; 297: 113717, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33503523

RESUMO

Increasing evidence suggests that the inflammatory system is activated in schizophrenia and antipsychotics may affect cytokines levels. we conducted a cross-sectional and prospective study.One hundred and thirteen patients and 58 normal subjects matched by gender, age were enrolled in the study. All the patients had risperidonemonotherapy and undertook a 10-week follow-up. Serum levels of IL-17 and IGF-1 were examined using the enzyme-linked immunosorbent assay and the Positive and Negative Symptoms Scale (PANSS) was applied to estimate the clinical symptoms in patients with schizophrenia. All procedures were repeated at the 10 weeks for patients group.The serum levels of IL-17 and IGF-1 in patients were significantly higher than in normal people. After treatment, IGF-1 levels in patients decreased significantly, whereas the IL-17 serum levels had no significant change compared to their baseline concentration. IGF-1 levels at the baseline were negatively associated with the reduction in negative symptoms score after controlling for age, gender distribution, education, smoking status, and WHR. Additionally, the magnitude of IGF-1 change was negatively correlated with negative symptoms score change after controlling for potential confounding variables. Results suggested that the inflammatory system is activated and serum IGF-1 may contribute to the pathophysiology of the negative symptoms of schizophrenia.

14.
Biomol NMR Assign ; 2021 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-33389547

RESUMO

The WhiB4 protein, a member of WhiB-like proteins, plays an important role in the survival and pathology of Mycobacterium tuberculosis (Mtb). As a transcription factor, WhiB4 regulates the expression of genes involved in maintaining redox homeostasis, central metabolism, and respiration. Furthermore, WhiB4 leads to the condensation of mycobacterial nucleoids and is capable of binding to DNA. WhiB4 contains four cysteine residues and exists in multiple forms under different redox environments, including a dimeric holo form with iron-sulfur cluster, multimeric disulfide-linked oxidized apo forms and monomeric reduced apo form. Here, we report the 1H, 13C, 15N chemical shifts of WhiB4 protein in its reduced apo state, providing a basis for the determination of its solution structure.

15.
Arthritis Res Ther ; 23(1): 41, 2021 01 27.
Artigo em Inglês | MEDLINE | ID: mdl-33499913

RESUMO

BACKGROUND: The efficacy and safety of ixekizumab (IXE) with and without continuous concomitant methotrexate (MTX), for up to 52 weeks of treatment, were evaluated in patients with active psoriatic arthritis (PsA). METHODS: Patients with active PsA who were biologic-naive (SPIRIT-P1) or had prior inadequate response to tumor necrosis factor inhibitors (SPIRIT-P2) were randomized to 80 mg IXE every 4 (IXE Q4W) or 2 weeks (IXE Q2W), after a 160-mg initial dose. In this post hoc analysis, efficacy and safety were assessed up to week 52 in the subgroups of patients who received (i) IXE as monotherapy and (ii) IXE along with a stable dose of MTX (no dose tapering or increase). Efficacy outcomes included, but were not limited to, the percentage of patients achieving the American College of Rheumatology (ACR) responses. RESULTS: Out of 455 patients initially randomized to IXE, 177 (38.9%) received monotherapy, 230 (50.5%) had concomitant MTX use, and 48 (10.5%) had other concomitant medication. Overall, 183 (40.2%) received IXE with a stable dose of concomitant MTX for 1 year. At week 52, the percentage of patients achieving ACR20/50/70 responses in IXE Q4W monotherapy versus concomitant MTX groups were 66.3% versus 55.3%, 48.4% versus 38.8%, and 35.8% versus 27.1%, respectively; these responses were generally similar with IXE Q2W. The safety profiles were similar between patients receiving IXE with or without concomitant MTX. CONCLUSIONS: In this post hoc analysis, treatment with IXE demonstrated sustained efficacy in patients with PsA up to 1 year of treatment, with or without concomitant MTX therapy. TRIAL REGISTRATION: ClinicalTrials.gov NCT01695239 and NCT02349295 .

16.
Hum Cell ; 2021 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-33486722

RESUMO

Epidermal differentiation and barrier function require well-controlled matriptase and prostasin proteolysis, in which the Kunitz-type serine protease inhibitor HAI-1 represents the primary enzymatic inhibitor for both proteases. HAI-1, however, also functions as a chaperone-like protein necessary for normal matriptase synthesis and intracellular trafficking. Furthermore, other protease inhibitors, such as antithrombin and HAI-2, can also inhibit matriptase and prostasin in solution or in keratinocytes. It remains unclear, therefore, whether aberrant increases in matriptase and prostasin enzymatic activity would be the consequence of targeted deletion of HAI-1 and so subsequently contribute to the epidermal defects observed in HAI-1 knockout mice. The impact of HAI-1 deficiency on matriptase and prostasin proteolysis was, here, investigated in HaCaT human keratinocytes. Our results show that HAI-1 deficiency causes an increase in prostasin proteolysis via increased protein expression and zymogen activation. It remains unclear, however, whether HAI-1 deficiency increases "net" prostasin enzymatic activity because all of the activated prostasin was detected in complexes with HAI-2, suggesting that prostasin enzymatic activity is still under tight control in HAI-1-deficient keratinocytes. Matriptase proteolysis is, however, unexpectedly suppressed by HAI-1 deficiency, as manifested by decreases in zymogen activation, shedding of active matriptase, and matriptase-dependent prostasin zymogen activation. This suppressed proteolysis results mainly from the reduced ability of HAI-1-deficient HaCaT cells to activate matriptase and the rapid inhibition of nascent active matriptase by HAI-2 and other yet-to-be-identified protease inhibitors. Our study provides novel insights with opposite impacts by HAI-1 deficiency on matriptase versus prostasin proteolysis in keratinocytes.

18.
Dalton Trans ; 50(4): 1293-1299, 2021 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-33393532

RESUMO

An ionothermal reaction of lanthanoid salts with tetraethyl-p-xylenediphosphonate (tepxdp) in ionic liquids, such as choline chloride and malonic acid, resulted in the formation of three novel lanthanoid-organic coordination networks with the formula [Ln(H2pxdp)1.5]n {Ln = Tb (1), Dy (2) and Ho(3) and H4pxdp = p-xylenediphosphonic acid}. The structures, photoluminescence and magnetic properties of the three compounds were investigated in detail. Single crystal X-ray diffraction analysis revealed that the three compounds are isostructural and the Ln3+ ions show an unusual six-coordinate environment with the {LnO6} octahedron. In these compounds, each {PO3C} tetrahedron is corner-shared with two {LnO6} octahedra and each {LnO6} octahedron is corner-shared with six {PO3C} tetrahedra, thus forming an inorganic layer in the crystallographic ab plane. The inorganic layers are further connected by a phenyl group, leading to a three-dimensional framework. Compound 1 exhibits the strong and characteristic emission of TbIII with an impressive quantum yield of 46.2%. Detailed magnetic analysis demonstrated that compound 2 displays a slow magnetic relaxation of magnetization with multiple relaxation mechanisms. The anisotropic energy barrier and the pre-exponential factor τ0 are 51.2 K and 3.9 × 10-7 s, respectively, in the presence of a direct-current field of 500 Oe. This work demonstrates a successful strategy to isolate octahedrally coordinated lanthanoid complexes through ionothermal synthesis to exhibit the single-ion-magnet-like behaviour and photoluminescence properties.

19.
Nanoscale ; 2021 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-33506851

RESUMO

Two-dimensional (2D) magnetic CrI3 has received considerable research attention because of its intrinsic features, including insulation, Ising ferromagnetism, and stacking-order-dependent magnetism, as well as potential in spintronic applications. However, the current strategy for the production of ambient-unstable CrI3 thin layer is limited to mechanical exfoliation, which normally suffers from uncontrollable layer thickness, small size, and low yet unpredictable yield. Here, via a confined vapor epitaxy (CVE) method, we demonstrate the mass production of flower-like CrI3 monolayers on mica. Interestingly, we discovered the crucial role of K ions on the mica surface in determining the morphology of monolayer CrI3, reacting with precursors to form a KIx buffer layer. Meanwhile, the transport agent affects the thickness and size of the as-grown CrI3. Moreover, the Curie temperature of CrI3 is greatly affected by the interaction between CrI3 and the substrate. The monolayer CrI3 on mica could act as a magnetic substrate for valley Zeeman splitting enhancement of WSe2. We reckon our work represents a major advancement in the mass production of monolayer 2D CrI3 and anticipate that our growth strategy may be extended to other transition metal halides.

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