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1.
Brain Res ; : 148991, 2024 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-38754803

RESUMEN

BACKGROUND: The study aimed to investigate the potential pharmacological and toxicological differences between Vigabatrin (VGB) and its enantiomers S-VGB and R-VGB. The researchers focused on the toxic effects and antiepileptic activity of these compounds in a rat model. METHODS: The epileptic rat model was established by intraperitoneal injection of kainic acid, and the antiepileptic activity of VGB, S-VGB, and VGB was observed, focusing on the improvements in seizure latency, seizure frequency and sensory, motor, learning and memory deficits in epileptic rats, as well as the hippocampal expression of key molecular associated with synaptic plasticity and the Wnt/ß-catenin/GSK 3ß signaling pathway. The acute toxic test was carried out and the LD50 was calculated, and tretinal damages in epileptic rats were also evaluated. RESULT: The results showed that S-VGB exhibited stronger antiepileptic and neuroprotective effects with lower toxicity compared to VGB raceme. These findings suggest that S-VGB and VGB may modulate neuronal damage, glial cell activation, and synaptic plasticity related to epilepsy through the Wnt/ß-catenin/GSK 3ß signaling pathway. The study provides valuable insights into the potential differential effects of VGB enantiomers, highlighting the potential of S-VGB as an antiepileptic drug with reduced side effects. CONCLUSION: S-VGB has the highest antiepileptic effect and lowest toxicity compared to VGB and R-VGB.

2.
Inorg Chem ; 63(7): 3418-3427, 2024 Feb 19.
Artículo en Inglés | MEDLINE | ID: mdl-38323573

RESUMEN

The development of cutting-edge solid-state electrolytes (SSEs) entails a deep understanding of the underlying correlation between the structure and ionic conductivity. Generally, the structure of SSEs encompasses several interconnected crystal parameters, and their collective influence on Li+ transport can be challenging to discern. Here, we systematically investigate the structure-function relationship of halide spinel LixMgCl2+x (2 ≥ x ≥ 1) SSEs. A nonmonotonic trend in the ionic conductivity of LixMgCl2+x SSEs has been observed, with the maximum value of 8.69 × 10-6 S cm-1 achieved at x = 1.4. The Rietveld refinement analysis, based on neutron diffraction data, has revealed that the crystal parameters including cell parameters, Li+ vacancies, Debye-Waller factor, and Li-Cl bond length assume diverse roles in influencing ionic conductivity of LixMgCl2+x at different stages within the range of x values. Besides, mechanistic analysis demonstrates Li+ transport along three-dimensional pathways, which primarily governs the contribution to ionic conductivity of LixMgCl2+x SSEs. This study has shed light on the collective influence of crystal parameters on Li+ transport behaviors, providing valuable insights into the intricate relationship between the structure and ionic conductivity of SSEs.

3.
Nanoscale ; 15(32): 13420-13427, 2023 Aug 17.
Artículo en Inglés | MEDLINE | ID: mdl-37547928

RESUMEN

The lack of macroscopic magnetic moments makes antiferromagnetic materials promising candidates for high-speed spintronic devices. The 2D ternary V-based chalcogenides (VXYSe4; X, Y = Al, Ga) monolayers are investigated based on the density-functional theory and Monte Carlo simulations. The results reveal that the Néel temperature of the VGa2Se4 monolayer is 18 K with zigzag2-antiferromagnetic (AFM) spin ordering. Also, the magnetic ordering of V ions in VAl2Se4 and VAlGaSe4 monolayers prefer zigzag1-AFM coupling with Néel temperature of 47 K and 33 K, respectively. The magnetic anisotropy calculations demonstrate that the easy magnetization axis of the VXYSe4 monolayers is parallel to the y axis. In addition, the VXYSe4 monolayers can be adjusted from the AFM state to the ferromagnetic (FM) state under biaxial stretching, which can be attributed to the competition between d-p-d superexchange and d-d direct exchange caused by the variation of bond length. The transition temperature of VXYSe4 monolayers can be elevated above room temperature with the help of compression strain. In particular, the in-plane magnetic anisotropy is a robust characteristic regardless of the magnitude of the applied biaxial strain. These explorations not only enrich the family of AFM monolayers with excellent stability but also provide distinctive ideas for the performance control of AFM materials and their applications in nanodevices.

4.
Mol Neurobiol ; 60(8): 4595-4617, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37126129

RESUMEN

Increasing data suggest a crucial role of circadian rhythm in regulating metabolic and neurological diseases, and Bmal1 is regarded as a key regulator of circadian transcription. The aim of this study is to investigate the role of Bmal1 in the disruption of circadian rhythm and neuropsychiatric injuries in type 2 diabetes mellitus (T2DM). A T2DM model was induced by the combination of high-fat-diet (HFD) and streptozotocin (STZ) in vivo or HT-22 cells challenged with palmitic-acid (PA) in vitro. The glucolipid metabolism indicators, behavioral performance, and expression of synaptic plasticity proteins and circadian rhythm-related proteins were detected. These changes were also observed after interference of Bmal1 expression via overexpressed plasmid or small interfering RNAs in vitro. The results showed that HFD/STZ could induce T2DM-like glycolipid metabolic turmoil and abnormal neuropsychiatric behaviors in mice, as indicated by the increased concentrations of fasting blood-glucose (FBG), HbA1c and lipids, the impaired glucose tolerance, and the decreased preference index of novel object or novel arm in the novel object recognition test (NOR) and Y-maze test (Y-maze). Consistently, the protein expression of synaptic plasticity proteins and circadian rhythm-related proteins and the positive fluorescence intensity of MT1B and Bmal1 were decreased in the hippocampus of HFD/STZ-induced mice or PA-challenged HT-22 cells. Furthermore, overexpression of Bmal1 could improve the PA-induced lipid metabolic dysfunction and increase the decreased expressions of synaptic plasticity proteins and circadian rhythm-related proteins, and vice versa. These results suggested a crucial role of Bmal1 in T2DM-related glycolipid metabolic disorder and neuropsychiatric injury, which mechanism might be involved in the regulation of synaptic plasticity and circadian rhythms.


Asunto(s)
Diabetes Mellitus Tipo 2 , Animales , Ratones , Factores de Transcripción ARNTL/genética , Ritmo Circadiano/fisiología , Diabetes Mellitus Tipo 2/complicaciones , Diabetes Mellitus Tipo 2/metabolismo
5.
Phys Chem Chem Phys ; 25(17): 12450-12457, 2023 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-37096403

RESUMEN

Lead-free perovskites (A3B2X9) have drawn much attention in recent years. However, a thorough understanding of these materials is still in its early stages. This is because A3B2X9 perovskites have large-scale component tunability, in which the A+, B3+, and X- ions can be replaced or partially substituted with other elements. Here, based on density functional theory and machine learning techniques we propose a data-driven method to find suitable configurations for photocatalytic water splitting. By replacing atoms in A3B2X9, 3.4 million configurations are constructed and studied. Our results show that the substitutional position plays an important role in determining the photocatalytic performance. Specifically, the co-existence of Br and I elements is favorable for X-sites, while for B-site atoms, it is better to choose atoms from groups IIIB and IIIA with a period greater than 3. Considering their rarity and toxicity, we believe that In is a good choice for B-sites and propose CsRb2BiInBr5I4 as a promising candidate. These results may provide guidance for the discovery of novel lead-free perovskites for photocatalytic applications.

6.
Artículo en Inglés | MEDLINE | ID: mdl-36774641

RESUMEN

The breaking of the out-of-plane symmetry makes a two-dimensional (2D) Janus monolayer a new platform to explore the coupling between ferroelectricity and ferromagnetism. Using density functional theory in combination with Monte Carlo simulations, we report a novel phase-switchable 2D multiferroic material VInSe3 with large intrinsic out-of-plane spontaneous electric polarization and a high Curie temperature (Tc). The structural transition energy barrier between the two phases is determined to be 0.4 eV, indicating the switchability of the electric polarizations and the potential ferroelectricity. Carrier doping can boost the Curie temperature above room temperature, attributing to the enhanced magnetic exchange interaction. A transition from the ferromagnetic (FM) state to the antiferromagnetic (AFM) state can be induced by carrier doping in octahedra-VInSe3, while FM coupling is well-preserved in tetrahedron-VInSe3, which can be regulated to be either an XY or Ising magnet at an appropriate carrier concentration. These findings not only enrich the family of high-Tc low-dimensional monolayers but also offer a new direction for the design and multifunctional application of multiferroic materials.

7.
RSC Adv ; 12(45): 29291-29299, 2022 Oct 11.
Artículo en Inglés | MEDLINE | ID: mdl-36320760

RESUMEN

The structure and electronic properties of puckered GeS nanotubes have been investigated using first-principles density functional theory calculation. Our results show that both the armchair and zigzag GeS nanotubes are semiconductor materials with an adjustable band gap. The band gap increases gradually with increasing the tube diameter, and slowly converges to the monolayer limit. On the application of strain, the GeS nanotubes provide interesting strain-induced band gap variation. When the compressive strain reached 20%, zigzag GeS nanotubes are completely transformed into armchair GeS nanotubes. In addition, the elastic properties of the relatively stable armchair GeS nanotubes have been studied, the Young's modulus of the armchair (11, 11), (13, 13) and (15, 15) nanotubes were calculated to be 227.488 GPa, 211.888 GPa and 213.920 GPa, respectively. Our work confirms that compared with carbon nanotubes, two-dimensional materials with a puckered structure are easier to realize phase transition by stress.

8.
Nanoscale ; 14(38): 14231-14239, 2022 Oct 06.
Artículo en Inglés | MEDLINE | ID: mdl-36128830

RESUMEN

Two-dimensional (2D) ferro-type materials have received great attention owing to the remarkable polarization effect in optoelectronics and spintronics. Using the first-principles method, the coupling between ferromagnetism and ferroelectricity is investigated in a multiferroic Janus 1T-FeSSe monolayer, which has a strong Stoner ferromagnetic ground state. The magnetic anisotropy energy (MAE) is apparently impacted by the out-of-plane asymmetry donated ferroelectricity, which is reflected by the asymmetry of the Z-MAE image. The easy magnetization axis of Janus FeSSe is the +y axis with a large MAE of 0.59 meV, rooting in unpaired d electrons of Fe atoms. The transformation of band splitting and Fermi surface can be effectively engineered by different magnetic polarization directions. The ferromagnetic (FM) coupling of the FeSSe monolayer is very robust under external strain within the range of -6% to 6%, while the strength of magnetic moment of Fe atoms and polarization are easily strain-engineered, the intrinsic mechanism of which can be elaborated by the GKA rules that depend on angles and distances. This multiferroic FeSSe monolayer provides a new platform for exploring the coupling of 2D ferromagnetism and ferroelectricity and designing low-dimensional multiferroic electronics.

9.
J Phys Chem Lett ; 13(31): 7228-7235, 2022 Aug 11.
Artículo en Inglés | MEDLINE | ID: mdl-35912454

RESUMEN

Searching for novel and high-performance two-dimensional (2D) materials is an important task for photocatalytic applications. Although multinary compounds exhibit more diversity in structure and properties in comparison to binary 2D materials, they are comparatively under-studied. Herein, using a machine-learning (ML) technique and high-throughput screening, we develop an efficient approach to accurately predict 2D multicomponent photocatalysts. Over 4000 monolayers are examined, and 75 multinary compounds are identified for photocatalytic applications. Considering our predictions, we find that the ternary and quaternary compounds A2P2X6 and ABP2X6 with A = Cu/Zn/Ge/Ag/Cd, B = Ga/In/Bi, and X = S/Se exhibit superior properties, making them promising candidates for overall water splitting. Thus, our work provides an efficient way to explore novel photocatalysts, which could stimulate further theoretical and experimental investigations on 2D multinary compounds for application in photocatalytic water splitting.

10.
Neurochem Int ; 159: 105385, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-35843421

RESUMEN

Resveratrol (RES) is a polyphenol with diverse beneficial pharmacological activities, and our previous results have demonstrated its neuroprotective potential. The purpose of this study was to investigate the therapeutic effect of RES in Alzheimer's disease (AD)-like behavioral dysfunction induced by streptozotocin (STZ) and explore it's potential mechanism of action. STZ was microinjected bilaterally into the dorsal hippocampus of C57BL/6J mice at a dose of 3 mg/kg, and RES was administered intragastrically at a dose of 25 mg/kg for 5 weeks. Neurobehavioral performance was observed, and serum concentrations of insulin and Nesfatin-1 were measured. Moreover, the protein expression of amyloid beta 1-42 (Aß1-42), Tau, phosphorylated Tau (p-Tau) (Ser396), synaptic ras GTPase activation protein (SynGAP), postsynaptic density protein 95 (PSD95), synapsin-1, synaptogomin-1, and key molecules of the Wnt/ß-catenin signaling pathway in the hippocampus and prefrontal cortex (PFC) were assessed. Finally, pathological damage to hippocampal tissue was examined by Nissl and immunofluorescence staining. The results showed that compared with the controls, bilateral hippocampal microinjections of STZ induced task-specific learning and memory impairments, as indicated by the disadvantaged performances in the novel object recognition test (NOR) and Morris water maze (MWM), but not the contextual fear conditioning test (CFC). Treatment with RES could improve these behavioral disadvantages. The serum concentrations of insulin and Nesfatin-1 in the model group were remarkably higher than those of the control group. In addition, protein expression of Aß1-42, Tau, and p-Tau (Ser396) was increased but expression of SynGAP, PSD95, brain-derived neurotrophic factor (BDNF), and p-GSK-3ß/GSK-3ß were decreased in the hippocampus. Although the protein expression of BDNF and SynGAP was also markedly decreased in the PFC of the model mice, there was no significant difference among groups in the protein expression of PSD95, BDNF, synapsin-1, synaptogomin-1, and p-GSK-3ß/GSK-3ß. RES (25 mg/kg) reversed the enhanced insulin level, the abnormal protein expression of Aß1-42, Tau, and p-Tau (Ser396) in the hippocampus and PFC, and the hippocampal protein expression of SynGAP, PSD95 and BDNF. In addition, RES reversed the STZ-induced decrease in the number of Nissl bodies and the increase in fluorescence intensity of IBA1 in the hippocampal CA1 region. These findings indicate that RES could ameliorate STZ-induced AD-like neuropathological injuries, the mechanism of which could be partly related to its regulation of BDNF expression and synaptic plasticity-associated proteins in the hippocampus.


Asunto(s)
Enfermedad de Alzheimer , Insulinas , Enfermedad de Alzheimer/metabolismo , Péptidos beta-Amiloides/metabolismo , Péptidos beta-Amiloides/toxicidad , Animales , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Modelos Animales de Enfermedad , Glucógeno Sintasa Quinasa 3 beta/metabolismo , Hipocampo/metabolismo , Insulinas/efectos adversos , Insulinas/metabolismo , Aprendizaje por Laberinto , Trastornos de la Memoria/inducido químicamente , Trastornos de la Memoria/tratamiento farmacológico , Trastornos de la Memoria/metabolismo , Ratones , Ratones Endogámicos C57BL , Resveratrol/farmacología , Resveratrol/uso terapéutico , Estreptozocina/toxicidad , Sinapsinas/metabolismo , Sinapsinas/farmacología , Sinapsinas/uso terapéutico
11.
Artículo en Inglés | MEDLINE | ID: mdl-35575692

RESUMEN

For materials lacking inversion symmetries, an interband transition induced by a photon may result in excited electrons (holes) experiencing a spatial shift leading to generation of directional photocurrents. This phenomenon known as bulk photovoltaic effect (BPVE) shift photocurrent (SPC) has recently attracted immense attention owing to its potential in generating photovoltages that are not restricted by Shockley-Queisser limitations imposed by materials' electronic band gaps. The BPVE was recently reformulated in a quantum mechanics viewpoint as the change in the geometrical phase upon photoexcitation and can now be promptly calculated from Bloch wave functions generated by first-principles calculations. The SPC of an electron (hole) is robust against crystal defects and impurities both in the interior and the surface and can be less dissipative and ultrafast. Herein, an emergence of colossal SPC in a pristine two-dimensional (2D) single-layer α-SbP crystal is predicted from first-principles calculations. An external electric field is further applied on the 2D crystal, and a large SPC enhancement is achieved. The locations of the SPC peaks due to both in-plane and out-of-plane responses suggest that α-SbP can generate a large photocurrent both in visible-light and ultraviolet regions. Single-layer 2D α-SbP is thus an excellent material for strong SPC. This finding is thus expected to open a pathway to exploring efficient photovoltaic devices based on monolayer α-SbP and similar materials.

12.
Nanoscale ; 14(6): 2511-2520, 2022 Feb 10.
Artículo en Inglés | MEDLINE | ID: mdl-35103742

RESUMEN

The electronic properties of layered two-dimensional (2D) transition-metal dichalcogenide (TMD) van der Waals (vdW) heterostructures are strongly dependent on their layer number (N). However, extremely large computational resources are required to investigate the layer-dependent TMD vdW heterostructures for every possible combination if N varies in a large range. Fortunately, the machine learning (ML) technique provides a feasible way to probe this problem. In this work, based on the density functional theory (DFT) calculations combined with the ML technique, we effectively predict the layer-dependent electronic properties of TMD vdW heterostructures composed of MoS2, WS2, MoSe2, WSe2, MoTe2, or WTe2, in which the layer number varies from 2-10. The cross-validation scores of our trained ML models in predicting the bandgaps as well as the band edge positions exceed 90%, suggesting excellent performance. The predicted results show that in the case of a few-layer system, the number of layers has a significant effect on the electronic properties. The bandgap and band alignment could be dramatically changed from bilayer to triple-layer heterostructures. However, with the increase of the number of layers, the electronic properties change, and some general trends can be summarized. When the layer number is larger than 8, the properties of the TMD heterostructures tend to be stable, and the influence of the layer number decreases. Based on these results, our work not only sheds light on the understanding of the layer-dependent electronic properties of multi-layer TMD vdW heterostructures, but also provides an efficient way to accelerate the discovery of functional materials.

13.
Sensors (Basel) ; 22(2)2022 Jan 14.
Artículo en Inglés | MEDLINE | ID: mdl-35062596

RESUMEN

An intelligent land vehicle utilizes onboard sensors to acquire observed states at a disorderly intersection. However, partial observation of the environment occurs due to sensor noise. This causes decision failure easily. A collision relationship-based driving behavior decision-making method via deep recurrent Q network (CR-DRQN) is proposed for intelligent land vehicles. First, the collision relationship between the intelligent land vehicle and surrounding vehicles is designed as the input. The collision relationship is extracted from the observed states with the sensor noise. This avoids a CR-DRQN dimension explosion and speeds up the network training. Then, DRQN is utilized to attenuate the impact of the input noise and achieve driving behavior decision-making. Finally, some comparative experiments are conducted to verify the effectiveness of the proposed method. CR-DRQN maintains a high decision success rate at a disorderly intersection with partially observable states. In addition, the proposed method is outstanding in the aspects of safety, the ability of collision risk prediction, and comfort.

14.
J Phys Chem Lett ; 13(1): 236-242, 2022 Jan 13.
Artículo en Inglés | MEDLINE | ID: mdl-34967635

RESUMEN

The achievement of new bonding patterns of atoms in compounds is of great importance, which usually induces interesting physical and chemical properties. Rich oxidation states, diverse bonding types, and unique aurophilic attraction endow gold (Au) as a distinctive element. Here we report that a pressure-induced Li5AuP2, identified by a swarm intelligence-based structural prediction, becomes the first example of Au with sp3 hybridization. The most remarkable feature of Li5AuP2 is that it contains various frameworks made by AuP4, AuLi4, LiP4, and blende-like Li-P units, exhibiting noncentrosymmetry. The charge transfer from Li to Au makes Au 6p orbitals activate and hybridize with the 6s one. On the other hand, Li donating electrons to P and polar Au-P covalence make the constituent atoms satisfy the octet rule, rendering Li5AuP2 with a semiconducting character and a large second-order nonlinear optical response in the near-infrared region. Our work represents a significant step toward extending the understanding of gold chemistry.

15.
Front Endocrinol (Lausanne) ; 13: 1068199, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36619542

RESUMEN

Purpose: To investigate the changes of plasma 25(OH)D levels in type 2 diabetes mellitus (T2DM) patients and explore its role in the dysfunction of glucose and lipid metabolism and cognition. Methods: One hundred and thirty-two T2DM patients were enrolled and the demographic and clinical data were collected. The plasma concentration of 25(OH)D was detected and the patients were divided into two groups including a Vitamin D insufficient (VDI) group and a normal VD group according to the clinical diagnostic criterial of VDI with the plasma 25(OH)D level less than 29 ng/mL. The glycolipid metabolic and routine blood biochemical indices were detected, the plasma concentrations of C-reactive protein (CRP), interleukin-6 (IL-6), soluble myeloid soluble trigger receptor 1 (sTREM1) were measured. The cognitive function was assessed using the Behavior Rating Inventory of Executive Function-Adult Version (BRIEF-A). The depressive symptomatology was assessed using the Center for Epidemiological Survey Depression Scale (CES-D). Sleep quality was assessed using the Pittsburgh sleep quality index (PSQI). Results: There were 70 T2DM patients with VDI (70/132, 53.03%) in this study. The plasma concentrations of glycated hemoglobin (HbA1c), fasting plasma glucose (FPG), postprandial blood glucose (PBG), IL-6, and sTREM1 were remarkably increased in T2DM patients with VDI as compared with that with the normal VD, accompanied with an elevated BRIEF-A scores. There was no significant difference between groups with regard to the indices of blood lipid, liver function, and scores in CES-D and PSQI. Moreover, results of Pearson correlation test showed that the plasma 25(OH)D levels were negatively correlated with HbA1c, FPG, PBG, CRP, IL-6, sTREM1, CES-D sum scores, and PSQI sum scores, but positively correlated with the plasma levels of Serum creatinine (Scr). Furthermore, result of Receiver Operating Characteristic (ROC) curve analysis showed a predictive role of VDI levels in discriminating T2DM patients with higher cognitive impairments, with the sensitivity and specificity being 62.12% and 62.12%, respectively. Conclusion: VDI is harmful for T2DM patients with a significant relation with the hyperglycosemia and cognitive dysfunction.


Asunto(s)
Disfunción Cognitiva , Diabetes Mellitus Tipo 2 , Adulto , Humanos , Diabetes Mellitus Tipo 2/metabolismo , Hemoglobina Glucada , Interleucina-6/metabolismo , Glucemia/análisis , Disfunción Cognitiva/complicaciones , Metabolismo de los Lípidos , Glucolípidos
16.
Front Psychiatry ; 12: 774192, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34925101

RESUMEN

Background: Repetitive transcranial magnetic stimulation (rTMS) has therapeutic effects on craving in methamphetamine (METH) use disorder (MUD). The chronic abuse of METH causes impairments in executive function, and improving executive function reduces relapse and improves treatment outcomes for drug use disorder. The purpose of this study was to determine whether executive function helped predict patients' responses to rTMS treatment. Methods: This study employed intermittent theta burst stimulation (iTBS) rTMS modalities and observed their therapeutic effects on executive function and craving in MUD patients. MUD patients from an isolated Drug Rehabilitation Institute in China were chosen and randomly allocated to the iTBS group and sham-stimulation group. All participants underwent the Behavior Rating Inventory of Executive Function - Adult Version Scale (BRIEF-A) and Visual Analog Scales (VAS) measurements. Sixty-five healthy adults matched to the general condition of MUD patients were also recruited as healthy controls. Findings: Patients with MUD had significantly worse executive function. iTBS groups had better treatment effects on the MUD group than the sham-stimulation group. Further Spearman rank correlation and stepwise multivariate regression analysis revealed that reduction rates of the total score of the BRIEF-A and subscale scores of the inhibition factor and working memory factor in the iTBS group positively correlated with improvements in craving. ROC curve analysis showed that working memory (AUC = 87.4%; 95% CI = 0.220, 0.631) and GEC (AUC = 0.761%; 95% CI = 0.209, 0.659) had predictive power to iTBS therapeutic efficacy. The cutoff values are 13.393 and 59.804, respectively. Conclusions: The iTBS rTMS had a better therapeutic effect on the executive function of patients with MUD, and the improved executive function had the potential to become a predictor for the efficacy of iTBS modality for MUD treatment. Clinical Trial Registration: ClinicalTrials.gov, identifier: ChiCTR2100046954.

17.
ACS Appl Mater Interfaces ; 13(48): 58144-58151, 2021 Dec 08.
Artículo en Inglés | MEDLINE | ID: mdl-34809427

RESUMEN

Monolayer MoS2 has emerged as one of the most promising candidate materials for future semiconductor devices because of its fascinating physical properties and optoelectronic performance. Recently, the utilization of alkali metal compounds as promoters in CVD growth has been demonstrated to be a facile strategy for growing monolayer MoS2 and other 2D TMDs with large domain sizes. In this work, we systematically investigated the residues derived from alkali metal compounds and the spontaneous n-doping effect on monolayer MoS2 in alkali metal compound-promoted CVD growth. When using NaOH and other alkali metal compounds as promoters, it is found that the Raman peak of the A1g mode red shifted with a broadening width and the PL intensity of the A peak decreased with a red shift, which was attributed to the spontaneous n-doping effect during growth. Moreover, the growth using varying amounts of NaOH promoter suggests that the n-doping level could be controlled by the amount of promoter. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary-ion mass spectroscopy (TOF-SIMS) showed the existence of cation-derived residues in the form of a Na-O cluster physiosorbed on top of monolayer MoS2, which was also confirmed by the transfer experiment. The NaOH treatment experiment and density functional theory (DFT) calculations demonstrate that sodium hydroxide clusters, which could be converted from a combination of Na-O clusters and water vapor, could produce an n-doping effect on monolayer MoS2. This study provides a facile route to controllably grow monolayer 2D materials with a desired doping level without further treatment.

18.
Nanoscale Horiz ; 6(10): 809-818, 2021 Sep 27.
Artículo en Inglés | MEDLINE | ID: mdl-34350925

RESUMEN

Angle-resolved polarized Raman spectroscopy (ARPRS) is widely used to determine the crystal orientations of anisotropic layered materials (ALMs), which is an essential step to study all of their anisotropic properties. However, the understanding of the ARPRS response of black phosphorous (BP) as a most widely studied ALM is still unsatisfactory. Here, we clarify two key controversies about the physical origin of the intricate ARPRS response and the determination of crystal orientations in BP. Through systematic ARPRS measurements, we show that the degree of anisotropy of the response evolves gradually and periodically with the BP thickness, eventually leading to the intricate response. Meanwhile, we find that using the Raman peak intensity ratio of the two Ag phonon modes, the crystal orientations of BP can be unambiguously distinguished via a concise inequality . Comprehensive analysis and first-principles calculations reveal that the external anisotropic interference effect and the intrinsic electron-phonon coupling are responsible for the observations.

19.
J Immunol ; 206(10): 2290-2300, 2021 05 15.
Artículo en Inglés | MEDLINE | ID: mdl-33911007

RESUMEN

Siglec-8 is an inhibitory receptor expressed on eosinophils and mast cells. In this study, we took advantage of a novel Siglec-8 transgenic mouse model to assess the impact of modulating IgE-dependent mast cell degranulation and anaphylaxis using a liposomal platform to display an allergen with or without a synthetic glycan ligand for Siglec-8 (Sig8L). The hypothesis is that recruitment of Siglec-8 to the IgE-FcεRI receptor complex will inhibit allergen-induced mast cell degranulation. Codisplay of both allergen and Sig8L on liposomes profoundly suppresses IgE-mediated degranulation of mouse bone marrow-derived mast cells or rat basophilic leukemia cells expressing Siglec-8. In contrast, liposomes displaying only Sig8L have no significant suppression of antigenic liposome-induced degranulation, demonstrating that the inhibitory activity by Siglec-8 occurs only when Ag and Sig8L are on the same particle. In mouse models of anaphylaxis, display of Sig8L on antigenic liposomes completely suppresses IgE-mediated anaphylaxis in transgenic mice with mast cells expressing Siglec-8 but has no protection in mice that do not express Siglec-8. Furthermore, mice protected from anaphylaxis remain desensitized to subsequent allergen challenge because of loss of Ag-specific IgE from the cell surface and accelerated clearance of IgE from the blood. Thus, although expression of human Siglec-8 on murine mast cells does not by itself modulate IgE-FcεRI-mediated cell activation, the enforced recruitment of Siglec-8 to the FcεRI receptor by Sig8L-decorated antigenic liposomes results in inhibition of degranulation and desensitization to subsequent Ag exposure.


Asunto(s)
Alérgenos/administración & dosificación , Anafilaxia/tratamiento farmacológico , Anafilaxia/genética , Antígenos CD/metabolismo , Antígenos de Diferenciación de Linfocitos B/metabolismo , Desensibilización Inmunológica/métodos , Sistemas de Liberación de Medicamentos/métodos , Inmunoglobulina E/metabolismo , Lectinas/metabolismo , Mastocitos/inmunología , Nanopartículas/química , Polisacáridos/administración & dosificación , Receptores de IgE/metabolismo , Anafilaxia/inmunología , Animales , Antígenos CD/genética , Antígenos de Diferenciación de Linfocitos B/genética , Degranulación de la Célula/efectos de los fármacos , Degranulación de la Célula/genética , Degranulación de la Célula/inmunología , Línea Celular Tumoral , Modelos Animales de Enfermedad , Humanos , Lectinas/genética , Ligandos , Liposomas , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Polisacáridos/metabolismo , Ratas , Receptores de IgE/genética , Resultado del Tratamiento
20.
Sci Rep ; 11(1): 9220, 2021 04 28.
Artículo en Inglés | MEDLINE | ID: mdl-33911168

RESUMEN

Src homology 2 domain-containing inositol 5-phosphatase 1 (SHIP-1) regulates the intracellular levels of phosphotidylinositol-3, 4, 5-trisphosphate, a phosphoinositide 3-kinase (PI3K) product. Emerging evidence suggests that the PI3K pathway is involved in allergic inflammation in the lung. Germline or induced whole-body deletion of SHIP-1 in mice led to spontaneous type 2-dominated pulmonary inflammation, demonstrating that SHIP-1 is essential for lung homeostasis. However, the mechanisms by which SHIP-1 regulates lung inflammation and the responsible cell types are still unclear. Deletion of SHIP-1 selectively in B cells, T cells, dendritic cells (DC) or macrophages did not lead to spontaneous allergic inflammation in mice, suggesting that innate immune cells, particularly group 2 innate lymphoid cells (ILC2 cells) may play an important role in this process. We tested this idea using mice with deletion of SHIP-1 in the hematopoietic cell lineage and examined the changes in ILC2 cells. Conditional deletion of SHIP-1 in hematopoietic cells in Tek-Cre/SHIP-1 mice resulted in spontaneous pulmonary inflammation with features of type 2 immune responses and airway remodeling like those seen in mice with global deletion of SHIP-1. Furthermore, when compared to wild-type control mice, Tek-Cre/SHIP-1 mice displayed a significant increase in the number of IL-5/IL-13 producing ILC2 cells in the lung at baseline and after stimulation by allergen Papain. These findings provide some hints that PI3K signaling may play a role in ILC2 cell development at baseline and in response to allergen stimulation. SHIP-1 is required for maintaining lung homeostasis potentially by restraining ILC2 cells and type 2 inflammation.


Asunto(s)
Fibrosis/patología , Células Madre Hematopoyéticas/patología , Linfocitos/patología , Fosfatidilinositol-3,4,5-Trifosfato 5-Fosfatasas/fisiología , Neumonía/patología , Animales , Fibrosis/etiología , Células Madre Hematopoyéticas/metabolismo , Inmunidad Innata/inmunología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Papaína/toxicidad , Neumonía/etiología
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