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1.
Adv Sci (Weinh) ; 11(7): e2302886, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38064179

RESUMO

Narrow bandgap materials have garnered significant attention within the field of broadband photodetection. However, the performance is impeded by diminished absorption near the bandgap, resulting in a rapid decline in photoresponsivity within the mid-wave infrared (MWIR) and long-wave infrared (LWIR) regions. Furthermore, they mostly worked in cryogenic temperature. Here, without the assistance of any complex structure and special environment, it is realized high responsivity covering ultra-broadband wavelength range (Ultraviolet (UV) to LWIR) in a single quasi-1D pseudogap (PG) system (TaSe4 )2 I nanoribbon, especially high responsivity (From 23.9 to 8.31 A W-1 ) within MWIR and LWIR region at room temperature (RT). Through direct probing the carrier relaxation process with broadband time-resolved transient absorption spectrum measurement, the underlying mechanism of majorly photoconductive effect is revealed, which causes an increased spectral weight extended to PG region. This work paves the way for realizing high-performance uncooled MWIR and LWIR detection by using quasi-1D PG materials.

2.
Small ; 19(33): e2300964, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37066740

RESUMO

The long-range magnetic ordering in frustrated magnetic systems is stabilized by coupling magnetic moments to various degrees of freedom, for example, by enhancing magnetic anisotropy via lattice distortion. Here, the unconventional spin-lattice coupled metamagnetic properties of atomically-thin CrOCl, a van der Waals antiferromagnet with inherent magnetic frustration rooted in the staggered square lattice, are reported. Using temperature- and angle-dependent tunneling magnetoconductance (TMC), in complementary with magnetic torque and first-principles calculations, the antiferromagnetic (AFM)-to-ferrimagnetic (FiM) metamagnetic transitions (MTs) of few-layer CrOCl are revealed to be triggered by collective magnetic moment flipping rather than the established spin-flop mechanism, when external magnetic field (H) enforces a lattice reconstruction interlocked with the five-fold periodicity of the FiM phase. The spin-lattice coupled MTs are manifested by drastic jumps in TMC, which show anomalous upshifts at the transition thresholds and persist much higher above the AFM Néel temperature. While the MTs exhibit distinctive triaxial anisotropy, reflecting divergent magnetocrystalline anisotropy of the c-axis AFM ground state, the resulting FiM phase has an a-c easy plane in which the magnetization axis is freely rotated by H. At the 2D limit, such a field-tunable FiM phase may provide unique opportunities to explore exotic emergent phenomena and novel spintronics devices.

3.
Sci Adv ; 8(22): eabn4273, 2022 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-35658041

RESUMO

The recent discovery of superconductivity at the interfaces between KTaO3 and EuO (or LaAlO3) gives birth to the second generation of oxide interface superconductors. This superconductivity exhibits a strong dependence on the surface plane of KTaO3, in contrast to the seminal LaAlO3/SrTiO3 interface, and the superconducting transition temperature Tc is enhanced by one order of magnitude. For understanding its nature, a crucial issue arises: Is the formation of oxide interfaces indispensable for the occurrence of superconductivity? Exploiting ionic liquid (IL) gating, we are successful in achieving superconductivity at KTaO3(111) and KTaO3(110) surfaces with Tc up to 2.0 and 1.0 K, respectively. This oxide-IL interface superconductivity provides a clear evidence that the essential physics of KTaO3 interface superconductivity lies in the KTaO3 surfaces doped with electrons. Moreover, the controllability with IL technique paves the way for studying the intrinsic superconductivity in KTaO3.

4.
Adv Mater ; 34(6): e2108550, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34871466

RESUMO

Intercalation and stacking-order modulation are two active ways in manipulating the interlayer interaction of transition metal dichalcogenides (TMDCs), which lead to a variety of emergent phases and allow for engineering material properties. Herein, the growth of Pb-intercalated TMDCs-Pb(Ta1+x Se2 )2 , the first 124-phase, is reported. Pb(Ta1+x Se2 )2 exhibits a unique two-step first-order structural phase transition at around 230 K. The transitions are solely associated with the stacking degree of freedom, evolving from a high-temperature (high-T) phase with ABC stacking and R3m symmetry to an intermediate phase with AB stacking and P3m1, and finally to a low-temperature (low-T) phase again with R3msymmetry, but with ACB stacking. Each step involves a rigid slide of building blocks by a vector [1/3, 2/3, 0]. Intriguingly, gigantic lattice contractions occur at the transitions on warming. At low-T, bulk superconductivity with Tc  ≈ 1.8 K is observed. The underlying physics of the structural phase transitions are discussed from first-principle calculations. The symmetry analysis reveals topological nodal lines in the band structure. The results demonstrate the possibility of realizing higher-order metal-intercalated phases of TMDCs and advance the knowledge of polymorphic transitions, and may inspire stacking-order engineering in TMDCs and beyond.

5.
ACS Appl Mater Interfaces ; 13(50): 60200-60208, 2021 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-34883018

RESUMO

Magnetic tunnel junctions (MTJs), ferroelectric/antiferroelectric tunnel junctions (FTJs/AFTJs), and multiferroic tunnel junctions (MFTJs) have recently attracted significant interest for technological applications of nanoscale memory devices. Until now, most of them are based on perovskite oxide heterostructures with a relatively high resistance-area (RA) product and low resistance difference unfavorable for practical applications. The recent discovery of the two-dimensional (2D) van der Waals (vdW) ferroelectric (FE) and magnetic materials has opened a new route to realize tunnel junctions with high performance and atomic-scale dimensions. Here, using first-principles calculations, we propose a new type of 2D tunnel junction: an antiferroelectric magnetic tunnel junction (AFMTJ), which inherits the features of both MTJ and AFTJ. This AFMTJ is composed of monolayer CuInP2S6 (CIPS) sandwiched between 2D magnetic electrodes of CrSe2. The AFTJ with nonmagnetic electrodes of TiSe2 on both sides of CIPS and the asymmetric AFTJ with both CrSe2 and TiSe2 electrodes are also investigated. Based on quantum-mechanical modeling of the electronic transport, sizeable tunneling electroresistance effects and multiple nonvolatile resistance states are demonstrated. More importantly, a remarkably low RA product (less than 0.1 Ω·µm2) makes the proposed vdW AFMTJs superior to the conventional MFTJs in terms of their promising nonvolatile memory applications. Our calculations provide new guidance for the experiment and application of nanoscale memory devices.

6.
Materials (Basel) ; 14(21)2021 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-34771819

RESUMO

In this study, we measure the in-plane transport properties of high-quality Ba(Fe0.914Co0.086)2As2 single crystals. Signatures of vortex unbinding Berezinskii-Kosterlitz-Thouless (BKT) transition are shown from both the conventional approach and the Fisher-Fisher-Huse dynamic scaling analysis, in which a characteristic Nelson-Kosterlitz jump is demonstrated. We also observe a non-Hall transverse signal exactly at the superconducting transition, which is explained in terms of guided motion of unbound vortices.

7.
Science ; 374(6573): 1381-1385, 2021 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-34709939

RESUMO

A sufficiently large supercurrent can close the energy gap in a superconductor and create gapless quasiparticles through the Doppler shift of quasiparticle energy caused by finite Cooper pair momentum. In this gapless superconducting state, zero-energy quasiparticles reside on a segment of the normal-state Fermi surface, whereas the remaining Fermi surface is still gapped. We use quasiparticle interference to image the field-controlled Fermi surface of bismuth telluride (Bi2Te3) thin films under proximity effect from the superconductor niobium diselenide (NbSe2). A small applied in-plane magnetic field induces a screening supercurrent, which leads to finite-momentum pairing on the topological surface states of Bi2Te3. We identify distinct interference patterns that indicate a gapless superconducting state with a segmented Fermi surface. Our results reveal the strong impact of finite Cooper pair momentum on the quasiparticle spectrum.

8.
Neurol Sci ; 42(9): 3605-3613, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34236554

RESUMO

BACKGROUND: Atherosclerosis is the most common cause of ischemia stroke. Computed tomographic angiography (CTA) and digital subtraction angiography (DSA) are used to evaluate the degree of lumen stenosis. However, these examinations are invasive and can only reveal mild to moderate stenosis. High-resolution magnetic resonance imaging (HRMRI) seems a more intuitive way to show the pathological changes of vascular wall. Hence, we conducted a systematic retrospective study to determine the characteristics of symptomatic plaques in patients with intracranial atherosclerosis on HRMRI and their association with the occurrence and recurrence of ischemic stroke events. METHODS: The PubMed database was searched for relevant studies reported from January 31, 2010, to October 31, 2020. RESULTS: We selected 14 clinical outcome studies. We found that plaque enhancement and positive remodeling on HRMRI indicate symptomatic plaques. Besides, intraplaque hemorrhage and positive remodeling index are closely related to the occurrence of stroke. However, it is still controversial whether the initial enhancement of plaque and the occurrence and recurrence of stroke are related. There is also no significant correlation between vascular stenosis and symptomatic plaque or the occurrence and recurrence of ischemic stroke. CONCLUSION: High-resolution magnetic resonance imaging can be used as an assessment tool to predict the risk of stroke onset and recurrence in patients with atherosclerosis, but further research is also needed.


Assuntos
Isquemia Encefálica , Arteriosclerose Intracraniana , AVC Isquêmico , Placa Aterosclerótica , Acidente Vascular Cerebral , Isquemia Encefálica/complicações , Isquemia Encefálica/diagnóstico por imagem , Isquemia Encefálica/epidemiologia , Humanos , Arteriosclerose Intracraniana/complicações , Arteriosclerose Intracraniana/diagnóstico por imagem , Angiografia por Ressonância Magnética , Imageamento por Ressonância Magnética , Placa Aterosclerótica/diagnóstico por imagem , Estudos Retrospectivos , Acidente Vascular Cerebral/diagnóstico por imagem , Acidente Vascular Cerebral/epidemiologia
9.
Neurol Res ; 43(12): 1040-1049, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34229565

RESUMO

Background: Gadolinium enhancement on high resolution magnetic resonance imaging (HR-MRI) has been considered a sign of instability and inflammation of intracranial atherosclerotic plaques. Our research objective was to explore the relationship between the extent of plaque enhancement (PE), the degree of intracranial artery stenosis, and acute ischemic stroke events.Methods: HR-MRI was performed in 91 patients with intracranial vascular stenosis to determine the existence and intensity of PE.Results: Among 91 patients enrolled in the trial, there were 43 patients in the acute/subacute group (≤1 month from ischemic stroke event), 15 patients in the chronic group (>1 month from ischemic stroke event), and 33 patients in the non-culprit plaques group (no ischemic stroke event). A total of 105 intracranial atherosclerotic plaques were detected in 91 patients. 14 (13.3%) were mild-stenosis plaques, 22 (21.0%) were moderate-stenosis plaques, and 69 (65.7%) were severe-stenosis plaques. There were 12 (11.4%), 18 (17.1%), and 75 (71.4%) plaques in the non-enhanced plaque group, the mild-enhancement group, and the significant-enhancement group, respectively. The degree of PE among the acute/subacute group, the chronic group, and the non-culprit plaque group had a significant difference (P = 0.005). Enhanced plaques were more often observed in culprit plaques (acute/subacute group and chronic group) than non-culprit plaques (96.7% vs 77.3%). Non-enhanced plaques were more often observed in non-culprit plaques than culprit plaques (acute/subacute group and chronic group) (22.7% vs 3.3%). And 36.6% of the enhanced plaques were non-culprit plaques. After performing univariate and multivariate logistic regression analysis, the results showed that strong plaque enhancement (P = 0.025, odds ratio [OR] 3.700, 95% confidence interval [95% CI] 1.182-11.583) and severe stenosis (P = 0.008, OR 4.393, 95%CI 1.481-13.030) were significantly associated with acute ischemic events.Conclusion: Enhanced plaques were more often observed in culprit plaques, and non-enhanced plaques were more often observed in non-culprit plaques. Moreover, significant plaque enhancement and severe ICAS were closely associated with acute ischemic events.


Assuntos
Gadolínio , AVC Isquêmico/etiologia , Neuroimagem/métodos , Placa Aterosclerótica/complicações , Placa Aterosclerótica/diagnóstico por imagem , Adulto , Idoso , Meios de Contraste , Feminino , Humanos , Arteriosclerose Intracraniana/complicações , Arteriosclerose Intracraniana/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade
10.
Nature ; 593(7857): 56-60, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33953409

RESUMO

Exciting phenomena may emerge in non-centrosymmetric two-dimensional electronic systems when spin-orbit coupling (SOC)1 interplays dynamically with Coulomb interactions2,3, band topology4,5 and external modulating forces6-8. Here we report synergetic effects between SOC and the Stark effect in centrosymmetric few-layer black arsenic, which manifest as particle-hole asymmetric Rashba valley formation and exotic quantum Hall states that are reversibly controlled by electrostatic gating. The unusual findings are rooted in the puckering square lattice of black arsenic, in which heavy 4p orbitals form a Brillouin zone-centred Γ valley with pz symmetry, coexisting with doubly degenerate D valleys of px origin near the time-reversal-invariant momenta of the X points. When a perpendicular electric field breaks the structure inversion symmetry, strong Rashba SOC is activated for the px bands, which produces spin-valley-flavoured D± valleys paired by time-reversal symmetry, whereas Rashba splitting of the Γ valley is constrained by the pz symmetry. Intriguingly, the giant Stark effect shows the same px-orbital selectiveness, collectively shifting the valence band maximum of the D± Rashba valleys to exceed the Γ Rashba top. Such an orchestrating effect allows us to realize gate-tunable Rashba valley manipulations for two-dimensional hole gases, hallmarked by unconventional even-to-odd transitions in quantum Hall states due to the formation of a flavour-dependent Landau level spectrum. For two-dimensional electron gases, the quantization of the Γ Rashba valley is characterized by peculiar density-dependent transitions in the band topology from trivial parabolic pockets to helical Dirac fermions.

11.
Neurol Sci ; 42(7): 2645-2651, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33954827

RESUMO

OBJECTIVE: We aim to determine the risk of acute ischemic stroke in patients with severe and non-severe coronavirus disease 2019 (COVID-19). METHODS: A literature search was conducted in the PubMed, Embase, Web of Science, and Cochrane Library databases until October 28, 2020. Studies covering COVID-19's severity classification data and COVID-19 patients with acute ischemic stroke were included. Two independent evaluators extracted data, and the random effects model was used to calculate the risk ratios (RR) and 95% confidence interval (95% CI) of acute ischemic stroke associated with COVID-19's severity. RESULTS: A total of 8 studies were included, involving 5266 patients. Among all COVID-19 patients, the total incidence of ischemic stroke was 1.76% (95% CI: 0.82-3.01). Severe patients have an increased risk of acute ischemic stroke compared with non-severe patients (RR = 3.53, 95% CI: 2.06-6.07, P < 0.0001; I2 = 12%). This association was also observed when COVID-19's severity was defined by clinical parameters (RR 2.91, 95% CI: 1.17-7.26, P = 0.02; I2 = 29%) and the need for intensive care (RR 4.47, 95% CI: 2.40-8.31, P < 0.0001; I2 = 0%). CONCLUSIONS: This meta-analysis shows that the severe course of COVID-19 is associated with an increased risk of acute ischemic stroke.


Assuntos
Isquemia Encefálica , COVID-19 , AVC Isquêmico , Acidente Vascular Cerebral , Isquemia Encefálica/complicações , Isquemia Encefálica/epidemiologia , Humanos , SARS-CoV-2 , Acidente Vascular Cerebral/epidemiologia
12.
ACS Appl Mater Interfaces ; 13(11): 13517-13523, 2021 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-33689259

RESUMO

Ferroelectricity exists in a variety of three- and two-dimensional materials and is of great significance for the development of electronic devices. However, the presence of ferroelectricity in one-dimensional materials is extremely rare. Here, we predict ferroelectricity in one-dimensional SbN and BiN nanowires. Their polarization strengths are 1 order of magnitude higher than ever reported values in one-dimensional structures. Moreover, we find that spontaneous spin polarization can be generated in SbN and BiN nanowires by moderate hole doping. This is the first time the coexistence of both ferroelectricity and ferromagnetism in a one-dimensional system has been reported. Our finding not only broadens the family of one-dimensional ferroelectric materials but also offers a promising platform for novel electronic and spintronic applications.

13.
Cell Commun Signal ; 19(1): 24, 2021 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-33627137

RESUMO

BACKGROUND: The oncogenic transcript factor c-Maf is stabilized by the deubiquitinase Otub1 and promotes myeloma cell proliferation and confers to chemoresistance. Inhibition of the Otub1/c-Maf axis is a promising therapeutic target, but there are no inhibitors reported on this specific axis. METHODS: A luciferase assay was applied to screen potential inhibitors of Otub1/c-Maf. Annexin V staining/flow cytometry was applied to evaluate cell apoptosis. Immunoprecipitation was applied to examine protein ubiquitination and interaction. Xenograft models in nude mice were used to evaluate anti-myeloma activity of AVT. RESULTS: Acevaltrate (AVT), isolated from Valeriana glechomifolia, was identified based on a bioactive screen against the Otub1/c-Maf/luciferase system. AVT disrupts the interaction of Otub1/c-Maf thus inhibiting Otub1 activity and leading to c-Maf polyubiquitination and subsequent degradation in proteasomes. Consistently, AVT inhibits c-Maf transcriptional activity and downregulates the expression of its target genes key for myeloma growth and survival. Moreover, AVT displays potent anti-myeloma activity by triggering myeloma cell apoptosis in vitro and impairing myeloma xenograft growth in vivo but presents no marked toxicity. CONCLUSIONS: The natural product AVT inhibits the Otub1/c-Maf axis and displays potent anti-myeloma activity. Given its great safety and efficacy, AVT could be further developed for MM treatment. Video Abstract.


Assuntos
Antineoplásicos Fitogênicos/uso terapêutico , Cisteína Endopeptidases/metabolismo , Inibidores de Cisteína Proteinase/uso terapêutico , Iridoides/uso terapêutico , Mieloma Múltiplo/tratamento farmacológico , Proteínas Proto-Oncogênicas c-maf/antagonistas & inibidores , Animais , Antineoplásicos Fitogênicos/farmacologia , Apoptose/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Cisteína Endopeptidases/genética , Inibidores de Cisteína Proteinase/farmacologia , Feminino , Humanos , Iridoides/farmacologia , Camundongos Endogâmicos BALB C , Camundongos Nus , Mieloma Múltiplo/metabolismo , Mieloma Múltiplo/patologia , Proteínas Proto-Oncogênicas c-maf/genética , Proteínas Proto-Oncogênicas c-maf/metabolismo
14.
Neurol Sci ; 42(10): 4139-4148, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33528671

RESUMO

BACKGROUND: In recent years, the implantable cardiac monitors (ICM) have enhanced the recognition ability of atrial fibrillation (AF), which makes ICM have a new application in AF detection. We conducted a meta-analysis to determine the total incidence of newly found AF detected by ICM after cryptogenic stroke and to evaluate the factors related to the detection of AF. METHODS: A literature search was conducted in the PubMed, EMBASE, Web of Science, and Cochrane library databases until March 1, 2020. Studies that reported the detection rate of AF using ICM in cryptogenic stroke patients with negative initial AF screening were analyzed. RESULTS: A total of 23 studies were included. The overall proportion of AF detected by ICM in cryptogenic stroke patients was 25% (95% confidence interval [CI], 22-29%). The rate of AF detected by ICM was independently related to both cardiac monitoring time (coefficient = 0.0003; 95% CI, 0.0001-0.0005; P = 0.0001) and CHA2DS2-VASc score (coefficient = 0.0834; 95% CI, 0.0339-0.1329; P = 0.001). In subgroup analysis, we found a significant difference in the detection rate of AF for monitoring duration (< 6 months: 9.6% [95% CI, 4.4-16.4%]; ≥ 6 and ≤ 12 months: 19.3% [95% CI, 15.9-23.0%]; > 12 and ≤ 24 months: 23.6% [95% CI, 19.9-27.5%]; > 24 months and ≤ 36 months: 36.5% [95% CI, 24.2-49.9%]; P < 0.001), and continent (Europe: 26.5% [95% CI, 22.2-31.0%]; North America: 16.0% [95% CI, 10.3-22.6%]; Asia: 17.4% [95% CI, 12.4-23.0%]; P = 0.005). CONCLUSIONS: The longer the time of ICM monitoring after cryptogenic stroke, the higher the detection rate of AF. Further research is still needed to determine the optimal duration of long-term cardiac monitoring.


Assuntos
Fibrilação Atrial , AVC Isquêmico , Acidente Vascular Cerebral , Fibrilação Atrial/complicações , Fibrilação Atrial/diagnóstico , Fibrilação Atrial/epidemiologia , Eletrocardiografia Ambulatorial , Humanos , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/diagnóstico , Acidente Vascular Cerebral/epidemiologia , Fatores de Tempo
15.
Sci Bull (Beijing) ; 66(3): 243-249, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36654329

RESUMO

Topological materials and topological phases have recently become a hot topic in condensed matter physics. In this work, we report an In-intercalated transition-metal dichalcogenide InxTaSe2 (named 112 system), a topological nodal-line semimetal in the presence of both charge density wave (CDW) and superconductivity. In the x = 0.58 sample, the 2×3 commensurate CDW (CCDW) and the 2×2 CCDW are observed below 116 and 77 K, respectively. Consistent with theoretical calculations, the spin-orbital coupling gives rise to two twofold-degenerate nodal rings (Weyl rings) connected by drumhead surface states, confirmed by angle-resolved photoemission spectroscopy. Our results suggest that the 2×2 CCDW ordering gaps out one Weyl ring in accordance with the CDW band folding, while the other Weyl ring remains gapless with intact surface states. In addition, superconductivity emerges at 0.91 K, with the upper critical field deviating from the s-wave behavior at low temperature, implying possibly unconventional superconductivity. Therefore, we think this type of the 112 system may possess abundant physical states and offer a platform to investigate the interplay between CDW, nontrivial band topology and superconductivity.

16.
Acta Pharmacol Sin ; 42(8): 1338-1346, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33184448

RESUMO

Recent studies show that the expression of CCND1, a key factor in cell cycle control, is increased following the progress and deteriotation of glioma and predicts poor outcomes. On the other hand, dysregulated deubiquitinase USP10 also predicts poor prognosis for patients with glioblastoma (GBM). In the present study, we investigated the interplay between CCND1 protein and USP10 in GBM cells. We showed that the expression of CCND1 was significantly higher in both GBM tissues and GBM-derived stem cells. USP10 interacted with CCND1 and prevented its K48- but not K63-linked polyubiquitination in GBM U251 and HS683 cells, which led to increased CCND1 stability. Consistent with the action of USP10 on CCND1, knockdown of USP10 by single-guided RNA downregulated CCND1 and caused GBM cell cycle arrest at the G1 phase and induced GBM cell apoptosis. To implement this finding in the treatment of GBMs, we screened a natural product library and found that acevaltrate (AVT), an active component derived from the herbal plant Valeriana jatamansi Jones was strikingly potent to induce GBM cell apoptosis, which was confirmed by the Annexin V staining and activation of the apoptotic signals. Furthermore, we revealed that AVT concentration-dependently suppressed USP10-mediated deubiquitination on CCND1 therefore inducing CCND1 protein degradation. Collectively, the present study demonstrates that the USP10/CCND1 axis could be a promising therapeutic target for patients with GBMs.


Assuntos
Ciclina D1/metabolismo , Glioblastoma/metabolismo , Iridoides/farmacologia , Ubiquitina Tiolesterase/metabolismo , Ubiquitinação/fisiologia , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/fisiologia , Glioblastoma/tratamento farmacológico , Células HEK293 , Humanos , Ubiquitina Tiolesterase/antagonistas & inibidores , Ubiquitinação/efeitos dos fármacos
17.
Neurol Sci ; 41(6): 1451-1458, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32086687

RESUMO

BACKGROUND: Acute ischemic stroke leads to serious long-term disability and high mortality, especially in patients with large-vessel occlusive strokes. Nowadays, endovascular therapy is considered as an alternative treatment for these patients. Several studies have used thrombus characteristics based on non-contrast computed tomography (NCCT) and computed tomography angiography (CTA) to predict prognosis in ischemic stroke. We conducted a systematic review to identify potential imaging predictive factors for successful recanalization and improved clinical outcome after endovascular therapy in patients with large-vessel occlusion (LVO) in anterior arterial circulation. METHODS: The PubMed databases were searched for related studies reported between September 18, 2009, and September 18, 2019. RESULTS: We selected 11 studies on revascularization and 12 studies on clinical outcome. Patients with thrombus of higher Hounsfield unit (HU), shorter length, higher clot burden score, and increased thrombus permeability may achieve higher recanalization and improved clinical outcome, but the matter is still under debate. CONCLUSION: Imaging of thrombus can be used as an aseessment tool to predict the outcomes and it needs further studies in the future.


Assuntos
Arteriopatias Oclusivas/diagnóstico por imagem , Doenças Arteriais Cerebrais/diagnóstico por imagem , AVC Isquêmico/diagnóstico por imagem , Neuroimagem/normas , Avaliação de Resultados em Cuidados de Saúde/normas , Trombose/diagnóstico por imagem , Doenças Arteriais Cerebrais/complicações , Humanos , AVC Isquêmico/etiologia , Trombose/complicações
18.
Adv Sci (Weinh) ; 7(4): 1901939, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32099757

RESUMO

2D materials with nontrivial energy bands are highly desirable for exploring various topological phases of matter, as low dimensionality opens unprecedented opportunities for manipulating the quantum states. Here, it is reported that monolayer (ML) dialkali-metal monoxides, in the well-known 2H-MoS2 type lattice, host multiple symmetry-protected topological phases with emergent fermions, which can be effectively tuned by strain engineering. Based on first-principles calculations, it is found that in the equilibrium state, ML Na2O is a 2D double Weyl semimetal, while ML K2O is a 2D pseudospin-1 metal. These exotic topological states exhibit a range of fascinating effects, including universal optical absorbance, super Klein tunneling, and super collimation effect. By introducing biaxial or uniaxial strain, a series of quantum phase transitions between 2D double Weyl semimetal, 2D Dirac semimetal, 2D pseudospin-1 metal, and semiconductor phases can be realized. The results suggest monolayer dialkali-metal monoxides as a promising platform to explore fascinating physical phenomena associated with novel 2D emergent fermions.

19.
Sci Bull (Beijing) ; 65(15): 1252-1259, 2020 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-36747412

RESUMO

The electric control of magnetic properties based on magnetoelectric effect is crucial for the development of future data storage devices. Here, based on first-principles calculations, a strong magnetoelectric effect is proposed to effectively switch on/off the magnetic states as well as alter the in-plane/perpendicular easy axes of metal-phthalocyanine molecules (MPc) by reversing the electric polarization of the underlying two-dimensional (2D) ferroelectric α-In2Se3 substrate with the application of an external electric field. The mechanism originates from the different hybridization between the molecule and the ferroelectric substrate in which the different electronic states of surface Se layer play a dominant role. Moreover, the magnetic moments and magnetic anisotropy energies (MAE) of OsPc/In2Se3 can be further largely enhanced by a functionalized atom atop the OsPc molecule. The I-OsPc/In2Se3 system possesses large MAE up to 30 meV at both polarization directions, which is sufficient for room-temperature applications. These findings provide a feasible scheme to realize ferroelectric control of magnetic states in 2D limit, which have great potential for applications in nanoscale electronics and spintronics.

20.
Sci Rep ; 9(1): 12307, 2019 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-31444407

RESUMO

We study the quantum phase transitions in the nickel pnctides, CeNi2-δ(As1-xPx)2 (δ ≈ 0.07-0.22) polycrystalline samples. This series displays the distinct heavy fermion behavior in the rarely studied parameter regime of dilute carrier limit. We systematically investigate the magnetization, specific heat and electrical transport down to low temperatures. Upon increasing the P-content, the antiferromagnetic order of the Ce-4f moment is suppressed continuously and vanishes at xc ~ 0.55. At this doping, the temperature dependences of the specific heat and longitudinal resistivity display non-Fermi liquid behavior. Both the residual resistivity ρ0 and the Sommerfeld coefficient γ0 are sharply peaked around xc. When the P-content reaches close to 100%, we observe a clear low-temperature crossover into the Fermi liquid regime. In contrast to what happens in the parent compound x = 0.0 as a function of pressure, we find a surprising result that the non-Fermi liquid behavior persists over a nonzero range of doping concentration, xc < x < 0.9. In this doping range, at the lowest measured temperatures, the temperature dependence of the specific-heat coefficient is logarithmically divergent and that of the electrical resistivity is linear. We discuss the properties of CeNi2-δ(As1-xPx)2 in comparison with those of its 1111 counterpart, CeNi(As1-xPx)O. Our results indicate a non-Fermi liquid phase in the global phase diagram of heavy fermion metals.

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