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1.
Phys Rev Lett ; 132(9): 096101, 2024 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-38489621

RESUMEN

Kagome metals AV_{3}Sb_{5} (A=K, Rb, or Cs) exhibit intriguing charge density wave (CDW) instabilities, which interplay with superconductivity and band topology. However, despite firm observations, the atomistic origins of the CDW phases, as well as hidden instabilities, remain elusive. Here, we adopt our newly developed symmetry-adapted cluster expansion method to construct a first-principles-based effective Hamiltonian of CsV_{3}Sb_{5}, which not only reproduces the established inverse star of David (ISD) phase, but also predict a series of D_{3h}-n states under mild tensile strains. With such atomistic Hamiltonians, the microscopic origins of different CDW states are revealed as the competition of the second-nearest neighbor V-V pairs versus the first-nearest neighbor V-V and V-Sb couplings. Interestingly, the effective Hamiltonians also reveal the existence of ionic Dzyaloshinskii-Moriya interaction in the high-symmetry phase of CsV_{3}Sb_{5} and drives the formation of noncollinear CDW patterns. Our work thus not only deepens the understanding of the CDW formation in AV_{3}Sb_{5}, but also demonstrates that the effective Hamiltonian is a suitable approach for investigating CDW mechanisms, which can be extended to various CDW systems.

2.
Sci Bull (Beijing) ; 2024 May 17.
Artículo en Inglés | MEDLINE | ID: mdl-38824120

RESUMEN

Owing to the outstanding properties provided by nontrivial band topology, topological phases of matter are considered as a promising platform towards low-dissipation electronics, efficient spin-charge conversion, and topological quantum computation. Achieving ferroelectricity in topological materials enables the non-volatile control of the quantum states, which could greatly facilitate topological electronic research. However, ferroelectricity is generally incompatible with systems featuring metallicity due to the screening effect of free carriers. In this study, we report the observation of memristive switching based on the ferroelectric surface state of a topological semimetal (TaSe4)2I. We find that the surface state of (TaSe4)2I presents out-of-plane ferroelectric polarization due to surface reconstruction. With the combination of ferroelectric surface and charge-density-wave-gapped bulk states, an electric-switchable barrier height can be achieved in (TaSe4)2I-metal contact. By employing a multi-terminal-grounding design, we manage to construct a prototype ferroelectric memristor based on (TaSe4)2I with on/off ratio up to 103, endurance over 103 cycles, and good retention characteristics. The origin of the ferroelectric surface state is further investigated by first-principles calculations, which reveals an interplay between ferroelectricity and band topology. The emergence of ferroelectricity in (TaSe4)2I not only demonstrates it as a rare but essential case of ferroelectric topological materials, but also opens new routes towards the implementation of topological materials in functional electronic devices.

3.
Nat Commun ; 15(1): 3828, 2024 May 07.
Artículo en Inglés | MEDLINE | ID: mdl-38714653

RESUMEN

Stabilization of topological spin textures in layered magnets has the potential to drive the development of advanced low-dimensional spintronics devices. However, achieving reliable and flexible manipulation of the topological spin textures beyond skyrmion in a two-dimensional magnet system remains challenging. Here, we demonstrate the introduction of magnetic iron atoms between the van der Waals gap of a layered magnet, Fe3GaTe2, to modify local anisotropic magnetic interactions. Consequently, we present direct observations of the order-disorder skyrmion lattices transition. In addition, non-trivial topological solitons, such as skyrmioniums and skyrmion bags, are realized at room temperature. Our work highlights the influence of random spin control of non-trivial topological spin textures.

4.
Endokrynol Pol ; 74(2): 168-175, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37155300

RESUMEN

INTRODUCTION: The study aimed to explore the efficacy and safety of low-dose (LD) and regular-dose (RD) prednisone (PDN) for the treatment of subacute thyroiditis (SAT). MATERIAL AND METHODS: Patients were randomly allocated using the block randomization method to the 2 groups. The primary outcome was the time required for PDN treatment. Secondary outcomes included percentages of relapse, mean score for the Morisky Medication Adherence Scale-8© (MMAS-8), time required for symptoms to resolve, cumulative PDN dose (mg), and mean erythrocyte sedimentation rate (ESR) at 2 weeks and at baseline. RESULTS: The study cohort included 77 patients, randomized 74 participants, and 68 completed the study. There was no significant difference in the treatment duration between the LD and RD groups (55.31 ± 14.05 vs. 61.25 ± 19.95 days, p = 0.053). The mean difference in the time required for PDN treatment between the LD and RD groups was -1.86 [95% confidence interval (CI) = -10.64 to 6.92] days, which was within the non-inferiority margin of 7 days. There was a significant difference in the mean score for MMAS-8 between the LD and RD groups (5.84 ± 0.88 vs. 5.33 ± 1.12, p = 0.031). Also, there was a significant difference in the cumulative PDN dose between the LD and RD groups (504.22 ± 236.86 vs. 1002.28 ± 309.86, p = 0.046). The ESR at 2 weeks was statistically significant compared to baseline values in both groups, with pre-treatment and post-treatment ESRs of 49.91 ± 24.95 and 17.91 ± 12.60/mm/h, (p < 0.0001) in the LD group and 65.08 ± 21.77 and 17.23 ± 13.61/mm/h (p < 0.0001) in the RD group. CONCLUSION: Low-dose PDN therapy may be sufficient to achieve complete recovery and better outcomes for SAT. This study is registered with the Chinese Clinical Trial Registry (02/10/2021 ChiCTR2100051762).


Asunto(s)
Tiroiditis Subaguda , Humanos , Prednisona/uso terapéutico , Tiroiditis Subaguda/tratamiento farmacológico , Estudios Prospectivos , Resultado del Tratamiento , Recurrencia Local de Neoplasia
5.
Mol Biol Rep ; 39(9): 8883-9, 2012 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-22729905

RESUMEN

In the previous proteomic study of human placenta, transmembrane 7 superfamily member 1 (TM7SF1) was found enriched in lysosome compartments. TM7SF1 encodes a 399-amino acid protein with a calculated molecular mass of 45 kDa. Bioinformatic analysis of its amino acid sequence showed that it is a multipass transmembrane protein containing a potential dileucine-based lysosomal targeting signal and four putative N-glycosylation sites. By percoll-gradient centrifugation and further subfraction ways, the lysosomal solute and membrane compartments were isolated respectively. Immunoblotting analysis indicated that TM7SF1 was co-fractioned with lysosome associated membrane protein 2 (LAMP2), which was only detected in lysosomal membrane compartments whereas not detected in the solute compartments. Using specific anti-TM7SF1 antibody and double-immunofluorescence with lysosome membrane protein LAMP1 and Lyso-Tracker Red, the colocalisations of endogenous TM7SF1 with lysosome and late endosome markers were demonstrated. All of this indicated that TM7SF1 is an integral lysosome membrane protein. Rat ortholog of TM7SF1 was found to be strongly expressed in heart, liver, kidney and brain while not or low detected in other tissues. In summary, TM7SF1 was a lysosomal integral membrane protein that shows tissue-specific expression. As a G-protein-coupled receptor in lysosome membrane, TM7SF1 was predicted function as signal transduction across lysosome membrane.


Asunto(s)
Lisosomas/metabolismo , Proteínas de la Membrana/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Secuencia de Aminoácidos , Animales , Línea Celular , Expresión Génica , Humanos , Hígado/química , Hígado/metabolismo , Proteínas de la Membrana/química , Proteínas de la Membrana/genética , Ratones , Datos de Secuencia Molecular , Estructura Molecular , Especificidad de Órganos/genética , Transporte de Proteínas , Ratas , Receptores Acoplados a Proteínas G/química , Receptores Acoplados a Proteínas G/genética , Alineación de Secuencia , Fracciones Subcelulares
6.
Biomed Rep ; 3(3): 284-288, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-26137223

RESUMEN

The aims of the present study were to explore the efficacy of glycemic control and the risks of hypoglycemia with different methods of insulin therapy, and to provide reference data for the clinical treatment of diabetes. In this retrospective study, hospitalized patients diagnosed with type 2 diabetes between March and December 2014, in the Department of Endocrinology in the First Affiliated Hospital of Wannan Medical College, were divided into three groups, including an intensive insulin analogue therapy group, a premixed insulin analogue treatment group and a premixed human insulin therapy group. The efficacy of glycemic control and the incidence of hypoglycemia were determined in each of the insulin treatment groups. Compared with the other treatment groups, the intensive insulin analogue therapy group was associated with superior blood glucose control, shorter time to reach standard insulin regimen, shorter hospitalization time, fewer fluctuations in blood glucose levels and lower insulin dosage on discharge from hospital. However, this treatment was also associated with a high risk of hypoglycemia. In conclusion, when combined with the effective prevention of hypoglycemia and appropriate nursing care (especially in hospital care), intensive insulin analogue therapy may provide the greatest benefit to patients.

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