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1.
Nat Mater ; 2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-38589541

RESUMO

Robust ferroelectricity in nanoscale fluorite oxide-based thin films enables promising applications in silicon-compatible non-volatile memories and logic devices. However, the polar orthorhombic (O) phase of fluorite oxides is a metastable phase that is prone to transforming into the ground-state non-polar monoclinic (M) phase, leading to macroscopic ferroelectric degradation. Here we investigate the reversibility of the O-M phase transition in ZrO2 nanocrystals via in situ visualization of the martensitic transformation at the atomic scale. We reveal that the reversible shear deformation pathway from the O phase to the monoclinic-like (M') state, a compressive-strained M phase, is protected by 90° ferroelectric-ferroelastic switching. Nevertheless, as the M' state gradually accumulates localized strain, a critical tensile strain can pin the ferroelastic domain, resulting in an irreversible M'-M strain relaxation and the loss of ferroelectricity. These findings demonstrate the key role of ferroelastic switching in the reversibility of phase transition and also provide a tensile-strain threshold for stabilizing the metastable ferroelectric phase in fluorite oxide thin films.

2.
Acc Chem Res ; 57(8): 1188-1201, 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38578919

RESUMO

ConspectusCircularly polarized luminescence (CPL) generated by chiral luminescent systems has sparked enormous attention in multidisciplinary field as it brings infinite potential for applications, such as 3D optical displays, biological probes, and chiroptical sensors. Satisfying both the conditions of chirality and luminescence (including fluorescence or phosphorescence) is a prerequisite for constructing CPL materials. In this regard, whether in organic, inorganic, or hybrid systems, chiral and luminescent components generally involve effective coupling through covalent or noncovalent bonds. For covalent interactions, such as the copolymerization of chiral and luminescent monomers, although covalent bonds provide high stability for the system, they inevitably involve tedious preparation procedures that connect chirality and luminescence together. For noncovalent bonds, take supramolecular assembly as an example, chiral elements and achiral light-emitting units are chiral transferred through intermolecular interactions, and their advantages include the diversity of luminescent and chiral building blocks, the stimuli responsiveness brought by noncovalent bonds, as well as the potential amplification of CPL signals by coassembly. However, the stability of the assembly system may be poor, and the assembly chiroptical performance and morphology are difficult to predict. Gratifyingly, matching rule that do not rely on covalent together with noncovalent interactions allows for the effortless construction, modulation, as well as amplification of CPL systems.In this Account, we overview different strategies based on matching rule, including fluorescence-selective absorption, circularly polarized reflection, and circularly polarized fluorescence energy transfer (CPF-ET). Examples of these strategies are illustrated with a focus on helical polymers in light of their appealing structures and wide uses. For instance, for fluorescence-selective absorption, chiral helical polymers can convert racemic fluorescence light into a circularly polarized one with specific handedness by simply overlapping the helical polymer's circular dichroism (CD) spectra with the luminophore's emission spectra. For circularly polarized reflection, employing the selective reflection of certain handedness's circularly polarized light, the high helical twisting power (HTP) of the helical polymer in the cholesteric liquid crystals (N*-LCs) gives the system high glum. Additionally, for CPF-ET, only the emission spectrum of the donor and the absorption (or excitation) spectrum of the achiral acceptor are required to overlap, and no covalent or noncovalent interactions between the two are required. An outlook for the CPL materials related to matching rule which will avail the optimization and extension of this intriguing approach concludes the Account. We hope that the Account will offer insightful inspiration for the flourishing progress of chiroptical systems and present exciting opportunities.

3.
Acta Pharmacol Sin ; 2024 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-38902502

RESUMO

The vasopressin V2 receptor (V2R) is a validated therapeutic target for autosomal dominant polycystic kidney disease (ADPKD), with tolvaptan being the first FDA-approved antagonist. Herein, we used Gaussian accelerated molecular dynamics simulations to investigate the spontaneous binding of tolvaptan to both active and inactive V2R conformations at the atomic-level. Overall, the binding process consists of two stages. Tolvaptan binds initially to extracellular loops 2 and 3 (ECL2/3) before overcoming an energy barrier to enter the pocket. Our simulations result highlighted key residues (e.g., R181, Y205, F287, F178) involved in this process, which were experimentally confirmed by site-directed mutagenesis. This work provides structural insights into tolvaptan-V2R interactions, potentially aiding the design of novel antagonists for V2R and other G protein-coupled receptors.

4.
Angew Chem Int Ed Engl ; 63(1): e202315238, 2024 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-37953400

RESUMO

Ambient electrochemical ammonia (NH3 ) synthesis is one promising alternative to the energy-intensive Haber-Bosch route. However, the industrial requirement for the electrochemical NH3 production with amperes current densities or gram-level NH3 yield remains a grand challenge. Herein, we report the high-rate NH3 production via NO2 - reduction using the Cu activated Co electrode in a bipolar membrane (BPM) assemble electrolyser, wherein BPM maintains the ion balance and the liquid level of electrolyte. Benefited from the abundant Co sites and optimal structure, the target modified Co foam electrode delivers a current density of 2.64 A cm-2 with the Faradaic efficiency of 96.45 % and the high NH3 yield rate of 279.44 mg h-1 cm-2 in H-type cell using alkaline electrolyte. Combined with in situ experiments and theoretical calculations, we found that Cu optimizes the adsorption behavior of NO2 - and facilitates the hydrogenation steps on Co sites toward a rapid NO2 - reduction process. Importantly, this activated Co electrode affords a large NH3 production up to 4.11 g h-1 in a homemade reactor, highlighting its large-scale practical feasibility.

5.
Small ; 19(26): e2300961, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36942688

RESUMO

Fluorescent polymer particles have witnessed an increasing interest in recent years, owing to their fascinating physicochemical properties as well as wide-ranging applications. In this review, the state-of-the-art research progress of fluorescent polymer particles in the past five years is summarized. First, the synthesis protocols for fluorescent polymer particles, including emulsion polymerization, precipitation polymerization, dispersion polymerization, suspension polymerization, nanoprecipitation, self-assembly, and post-polymerization modification, are presented in detail. Then, the applications of the resulting beguiling particles in anticounterfeiting, chemical sensing, and biomedicine, are illustrated. Finally, the challenges and opportunities that exist in the field are pointed out. This review aims to offer important guidance and stimulate more research attention to this rapidly developing field.

6.
Small ; 19(43): e2303480, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37356057

RESUMO

The high conductivities and good mechanical properties of hydrogel electrolyte films are critical for energy storage devices with high flexibility, fast redox kinetics, and long life. Herein, a low water content (6.63 wt%) hydrogel film is prepared, and a favorable environment is created, with an electrochemical stability window of 2.26 V and a high ionic conductivity of 2.6 mS cm-1 . The hydrogel film exhibits good folding ability, low in-plane swelling, and anti-freezing abilities. These properties are benefitted by immobilizing free water molecules on the abundant oxygenic groups of polymer fibers in the hydrogel film, offering a unique 3D channel to allow Li+ to quickly transport along the polymer network. Therefore, the hydrogel film-based all-in-one flexible cell exhibits stable cycling performance with a retention of 81.8% of the initial capacity after 500 cycles at room temperature and 66.2% of capacity retention at -30 °C. Furthermore, the full cell with high cathode loading (≈21 mg cm-2 ) exhibits a high areal capacity of 2.5 mAh cm-2 (≈119 mAh g-1 ). The overall merits of flexible all-in-one quasi-solid-state batteries demonstrate high potential to be used for power wearable electronics.

7.
Macromol Rapid Commun ; 44(14): e2300106, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37014695

RESUMO

In the past few years, fluorescent materials have received significant attention due to their fascinating luminescent properties and wide-ranging applications. Polydimethylsiloxane (PDMS) has also attracted the interest of many researchers due to its remarkable performances. The combination of fluorescence and PDMS will undoubtedly produce abundant advanced multifunctional materials. Although numerous achievements have been made in this field, there is still no review to summarize the relevant research. This review summarizes the state-of-the-art achievements made in PDMS-based fluorescent materials (PFMs). First, the preparation of PFM is overviewed following a classification according to the fluorescent sources, including organic fluorescent molecules, perovskite, photoluminescent nanomaterials, and metal complexes. Their applications in sensors, fluorescent probes, multifunctional coatings, and anticounterfeiting are then introduced. Finally, the challenges and development trends in the field of PFMs are presented.


Assuntos
Complexos de Coordenação , Dimetilpolisiloxanos , Corantes Fluorescentes , Fluorescência
8.
BMC Musculoskelet Disord ; 24(1): 838, 2023 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-37875873

RESUMO

BACKGROUND: This meta-analysis compares the efficacy of unilateral biportal endoscopic transforaminal lumbar interbody fusion (UBE-TLIF) to conventional interbody fusion in lumbar degenerative diseases (LDD). METHODS: An extensive literature search was conducted in PubMed, Web of Science, and the Cochrane Library. Research related to UBE-TLIF published up to November 2022 was reviewed. The relevant articles were selected based on inclusion and exclusion criteria, as well as an evaluation of the quality of the data extraction literature. Meta-analysis was performed using Review Manager 5.3 software. RESULTS: This meta-analysis included six high-quality case-control trials (CCTs) involving 621 subjects. The clinical outcomes assessment showed no statistical differences in complication rates, fusion rates, leg pain VAS scores, or ODI scores. After UBE-TLIF, low back pain VAS scores were significantly improved with less intraoperative blood loss and a shorter hospital stay. A longer time was required for UBE-TLIF, however. CONCLUSION: Despite the lack of sufficient high quality randomized controlled trials (RCTs) in this study, the results of this meta-analysis suggest that UBE-TLIF is more effective than open surgery in terms of length of stay, blood loss reduction during surgery, and improved low back pain after surgery. Nevertheless, the evidence will be supplemented in the future by more and better quality multicenter randomized controlled trials.


Assuntos
Dor Lombar , Fusão Vertebral , Humanos , Endoscopia , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/cirurgia , Procedimentos Cirúrgicos Minimamente Invasivos/métodos , Ensaios Clínicos Controlados Aleatórios como Assunto , Estudos Retrospectivos , Fusão Vertebral/métodos , Resultado do Tratamento
9.
Chin J Traumatol ; 26(1): 8-13, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-35478089

RESUMO

Pediatric and adult spinal cord injuries (SCI) are distinct entities. Children and adolescents with SCI must suffer from lifelong disabilities, which is a heavy burden on patients, their families and the society. There are differences in Chinese and foreign literature reports on the incidence, injury mechanism and prognosis of SCI in children and adolescents. In addition to traumatic injuries such as car accidents and falls, the proportion of sports injuries is increasing. The most common sports injury is the backbend during dance practice. Compared with adults, children and adolescents are considered to have a greater potential for neurological improvement. The pathogenesis and treatment of pediatric SCI remains unclear. The mainstream view is that the mechanism of nerve damage in pediatric SCI include flexion, hyperextension, longitudinal distraction and ischemia. We also discuss the advantages and disadvantages of drugs such as methylprednisolone in the treatment of pediatric SCI and the indications and timing of surgery. In addition, the complications of pediatric SCI are also worthy of attention. New imaging techniques such as diffusion tensor imaging and diffusion tensor tractography may be used for diagnosis and assessment of prognosis. This article reviews the epidemiology, pathogenesis, imaging, clinical characteristics, treatment and complications of SCI in children and adolescents. Although current treatment cannot completely restore neurological function, patient quality of life can be enhanced. Continued developments and advances in the research of SCI may eventually provide a cure for children and adolescents with this kind of injury.


Assuntos
Traumatismos em Atletas , Traumatismos da Medula Espinal , Adulto , Criança , Humanos , Adolescente , Imagem de Tensor de Difusão/métodos , Qualidade de Vida , Traumatismos da Medula Espinal/epidemiologia , Traumatismos da Medula Espinal/etiologia , Traumatismos da Medula Espinal/terapia , Prognóstico , Medula Espinal/patologia
10.
Zhongguo Zhong Yao Za Zhi ; 48(14): 3736-3742, 2023 Jul.
Artigo em Zh | MEDLINE | ID: mdl-37475065

RESUMO

Molecularly imprinted polymers demonstrate outstanding performance in the research on trace ingredients because of their high selectivity. Stimuli-responsive molecularly imprinted polymers(STR-MIPs) with the introduction of different responsive groups on the basis of traditionally imprinted materials can undergo reversible transformations when exposed to external stimuli such as temperature, magnetism, pH or light. Such responsiveness, combined with the specific recognition, endows STR-MIPs with excellent perfor-mance in trace component studies. Traditional Chinese medicine(TCM) contains complex components with trace content, and thus STR-MIPs have broad application prospects in the enrichment analysis of trace components in TCM. This paper elaborates on the application of STR-MIPs in the enrichment analysis of trace components in TCM from the perspectives of different stimuli, summarized relevant research achievements in the recent five years to broaden the application fields of molecular imprinting, and proposed a few opi-nions about their future development.


Assuntos
Medicina Tradicional Chinesa , Impressão Molecular , Polímeros Molecularmente Impressos , Polímeros/química , Temperatura
11.
Zhongguo Zhong Yao Za Zhi ; 48(5): 1218-1228, 2023 Mar.
Artigo em Zh | MEDLINE | ID: mdl-37005806

RESUMO

In this study, ultra-performance liquid chromatography-quadrupole/time-of-flight mass spectrometry(UPLC-Q-TOF-MS) and gas chromatography-mass spectrometry(GC-MS) were combined with non-targeted metabonomic analysis based on multivariate statistics analysis, and the content of five indicative components in nardosinone was determined and compared by UPLC. The main chemical components of Nardostachyos Radix et Rhizoma with imitative wild cultivation and wild Nardostachyos Radix et Rhizoma were comprehensively analyzed. The results of multivariate statistical analysis based on liquid chromatography-mass spectrometry(LC-MS) and GC-MS were consistent. G1 and G2 of the imitative wild cultivation group and G8-G19 of the wild group were clustered into category 1, while G7 of the wild group and G3-G6 of the imitative wild cultivation group were clustered into category 2. After removing the outlier data of G1, G2, and G7, G3-G6 of the imitative wild cultivation group were clustered into one category, and G8-G19 of the wild group were clustered into the other category. Twenty-six chemical components were identified according to the positive and negative ion modes detected by LC-MS. The content of five indicative components(VIP>1.5) was determined using UPLC, revealing that chlorogenic acid, isochlorogenic acid A, isochlorogenic acid C, linarin, nardosinone, and total content in the imitative wild cultivation group were 1.85, 1.52, 1.26, 0.90, 2.93, and 2.56 times those in the wild group, respectively. OPLS-DA based on GC-MS obtained 10 diffe-rential peaks. Among them, the relative content of α-humulene and aristolene in the imitative wild cultivation group were extremely significantly(P<0.01) and significantly(P<0.05) higher than that in the wild group, while the relative content of 7 components such as 5,6-epoxy-3-hydroxy-7-megastigmen-9-one, γ-eudesmol, and juniper camphor and 12-isopropyl-1,5,9-trimethyl-4,8,13-cyclotetrade-catriene-1,3-diol was extremely significantly(P<0.01) and significantly(P<0.05) lower than that in the wild group, respectively. Therefore, the main chemical components of the imitative wild cultivation group and wild group were basically the same. However, the content of non-volatile components in the imitative wild cultivation group was higher than that in the wild group, and the content of some volatile components was opposite. This study provides scientific data for the comprehensive evaluation of the quality of Nardostachyos Radix et Rhizoma with imitative wild cultivation and wild Nardostachyos Radix et Rhizoma.


Assuntos
Medicamentos de Ervas Chinesas , Cromatografia Gasosa-Espectrometria de Massas , Cromatografia Líquida , Cromatografia Líquida de Alta Pressão , Medicamentos de Ervas Chinesas/química , Espectrometria de Massas em Tandem
12.
Gut ; 71(9): 1812-1820, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35017200

RESUMO

OBJECTIVE: The human gut fungal community, known as the mycobiome, plays a fundamental role in the gut ecosystem and health. Here we aimed to investigate the determinants and long-term stability of gut mycobiome among middle-aged and elderly adults. We further explored the interplay between gut fungi and bacteria on metabolic health. DESIGN: The present study included 1244 participants from the Guangzhou Nutrition and Health Study. We characterised the long-term stability and determinants of the human gut mycobiome, especially long-term habitual dietary consumption. The comprehensive multiomics analyses were performed to investigate the ecological links between gut bacteria, fungi and faecal metabolome. Finally, we examined whether the interaction between gut bacteria and fungi could modulate the metabolic risk. RESULTS: The gut fungal composition was temporally stable and mainly determined by age, long-term habitual diet and host physiological states. Specifically, compared with middle-aged individuals, Blastobotrys and Agaricomycetes spp were depleted, while Malassezia was enriched in the elderly. Dairy consumption was positively associated with Saccharomyces but inversely associated with Candida. Notably, Saccharomycetales spp interacted with gut bacterial diversity to influence insulin resistance. Bidirectional mediation analyses indicated that bacterial function or faecal histidine might causally mediate an impact of Pichia on blood cholesterol. CONCLUSION: We depict the sociodemographic and dietary determinants of human gut mycobiome in middle-aged and elderly individuals, and further reveal that the gut mycobiome may be closely associated with the host metabolic health through regulating gut bacterial functions and metabolites.


Assuntos
Microbioma Gastrointestinal , Micobioma , Adulto , Idoso , Bactérias , Ecossistema , Fezes/microbiologia , Fungos , Humanos , Pessoa de Meia-Idade , Micobioma/fisiologia
13.
BMC Plant Biol ; 22(1): 420, 2022 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-36045357

RESUMO

BACKGROUND: Cold is a major abiotic stress and Huanglongbing and citrus canker disease are two devastating bacterial diseases for citrus. The Ca2+-CBL-CIPK network is known to regulate different types of stress signalling in plants. How do CBL-CIPK signalling networks function in response to cold and infection by CLas or Xcc in citrus? RESULTS: Eight calcineurin B-like proteins (CBLs) and seventeen CBL-interacting protein kinases (CIPKs) were identified from the cold-tolerant satsuma mandarin 'Guijing2501' (Citrus. unshiu) and CLas/Xcc-sensitive sweet orange (C. sinensis). Phylogenetic analysis revealed that both CBL and CIPK family members in citrus were classified into an ancient and a recent clade according to their conserved domain characteristics and/or intron/exon structures. Genome duplication analysis suggested that both tandem and segmental duplications contributed to the amplification of the CBL and CIPK gene families in citrus under intense purifying selection, and the duplication events only existed in the recent clades. Expression comparison of the duplicated gene pairs indicated that the duplicated CBL and CIPK genes underwent functional differentiation. Further expression analysis identified that CBL1, 5, 6, and 8 and CIPK2, 8, 12, 15, 16, and 17 were significantly regulated by multiple stresses, including cold, Xcc infection and/or CLas infection, in citrus, whereas CBL2/7 and CIPK1/4/5/11/13/14 were independently highly regulated by cold and CIPK3 was uniquely responsive to Xcc infection. The combination analyses of targeted Y2H assay and expression analysis revealed that CBL6-CIPK8 was the common signalling network in response to cold and Xcc infection, while CBL6/CBL8-CIPK14 was uniquely responsive to cold in citrus. Further stable transformation and cold tolerance assay indicated that overexpression of CuCIPK16 enhanced the cold tolerance of transgenic Arabidopsis with higher POD activity and lower MDA content. CONCLUSIONS: In this study, evolution, gene expression and protein‒protein interaction analyses of citrus CBLs and CIPKs were comprehensively conducted over a genome-wide range. The results will facilitate future functional characterization of individual citrus CBLs and CIPKs under specific stresses and provide clues for the clarification of cold tolerance and disease susceptibility mechanisms in corresponding citrus cultivars.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Infecções Bacterianas , Citrus , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Ligação ao Cálcio/genética , Citrus/genética , Citrus/metabolismo , Expressão Gênica , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Proteínas Serina-Treonina Quinases
14.
Opt Express ; 30(4): 5981-6002, 2022 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-35209547

RESUMO

An accurate estimation of system parameters is of significance for the practical implementation of the simultaneous quantum key distribution and classical communication (SQCC) over a satellite-mediated link when considering the finite-size effect. In this paper, we propose a Kalman filter (KF)-enabled parameter estimation method for the SQCC over a satellite-mediated link. The fast and slow phase drift can be both estimated by using the improved vector KF carrier phase estimation algorithm, and thus the phase estimation error can be tracked in real time and be almost approximate to the theoretical mean square error limit. Taking advantage of the achieved phase estimation and the dual modulation of the SQCC scheme, the excess noise can be estimated with not only a higher precise but also a lower sacrificing rate of raw keys. Numerical simulations demonstrate the feasibility of the SQCC in both the downlink and uplink in terms of the finite-size effect. As a comparison of the Mth-power algorithm, we find that the secret key rate and achievable zenith angle perform better by using the vector KF algorithm. It paves the way of practical implementations for the SQCC system.

15.
Biomacromolecules ; 23(8): 3396-3406, 2022 08 08.
Artigo em Inglês | MEDLINE | ID: mdl-35786877

RESUMO

Chronic inflammation is a typical feature and a major impediment in refractory diabetic foot ulcer (DFU). High levels of extracellular cell-free nucleic acid (cfDNA) have recently been known to play a critical role in the cause of inflammation. Herein, we fabricated polyacrylamide-based cationic hydrogels and topically applied them to the ulcer of a diabetic rat model. The cfDNA level in the wound area was significantly reduced after hydrogel adsorption, and the level of inflammation was eliminated. In turn, the wound closure was significantly promoted without introducing systemic toxicity. Cationic hydrogels represent an effective material to combat uncontrolled inflammation in DFU.


Assuntos
Ácidos Nucleicos Livres , Diabetes Mellitus , Pé Diabético , Ácidos Nucleicos , Animais , Ácidos Nucleicos Livres/farmacologia , Pé Diabético/tratamento farmacológico , Hidrogéis/farmacologia , Inflamação , Ratos , Cicatrização
16.
Chirality ; 34(1): 48-60, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34725862

RESUMO

This article reports on a novel type of ternary chiral porous hybrid particles (TCPHPs) constructed by alkynylated cellulose nanocrystals (A-CNCs), helical substituted polyacetylene, and inorganic silica. The resulting TCPHPs combine the respective advantages of the three components. A-CNCs serve as stabilizer, co-monomer, and chiral source simultaneously and transfer their chirality to the resulting helical substituted polyacetylenes in the course of copolymerization with achiral acetylenic monomer following "sergeants and soldiers rule". Helical substituted polyacetylenes form chiral helical structures and thus endow TCPHPs with the anticipated optical activity. Inorganic silica constitutes the rigid framework and is covalently bonded with the organic components through hydrolysis of Si-O-Et groups. Phase separation between the organic and inorganic components renders TCPHPs with abundant pores. Scanning electron microscope (SEM) images confirm the formation of spherical particles with porous structures. Circular dichroism spectra demonstrate the optical activity of the chiral hybrid particles. The as-prepared TCPHPs exhibit capacity for enantio-differentiating performance towards chiral naproxen.


Assuntos
Nanopartículas , Dióxido de Silício , Celulose , Naproxeno , Polímero Poliacetilênico , Porosidade , Estereoisomerismo
17.
Nano Lett ; 21(24): 10409-10415, 2021 12 22.
Artigo em Inglês | MEDLINE | ID: mdl-34882420

RESUMO

Magnetic nanowires (NWs) are essential building blocks of spintronics devices as they offer tunable magnetic properties and anisotropy through their geometry. While the synthesis and compositional control of NWs have seen major improvements, considerable challenges remain for the characterization of local magnetic features at the nanoscale. Here, we demonstrate nonperturbative field distribution mapping in ultrascaled magnetic nanowires with diameters down to 6 nm by scanning nitrogen-vacancy magnetometry. This enables localized, minimally invasive magnetic imaging with sensitivity down to 3 µT Hz-1/2. The imaging reveals the presence of weak magnetic inhomogeneities inside in-plane magnetized nanowires that are largely undetectable with standard metrology and can be related to local fluctuations of the NWs' saturation magnetization. In addition, the strong magnetic field confinement in the nanowires allows for the study of the interaction between the stray magnetic field and the nitrogen-vacancy sensor, thus clarifying the contrasting formation mechanisms for technologically relevant magnetic nanostructures.


Assuntos
Diamante , Nanofios , Diamante/química , Campos Magnéticos , Magnetismo/métodos , Nitrogênio/química
18.
J Xray Sci Technol ; 30(3): 409-418, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35124575

RESUMO

OBJECTIVE: To evaluate image quality of deep learning-based image reconstruction (DLIR) in contrast-enhanced renal and adrenal computed tomography (CT) compared with adaptive statistical iterative reconstruction-Veo (ASiR-V). METHODS: We prospectively recruited 52 patients. All images were reconstructed with ASiR-V 30%, ASiR-V 70%, and DLIR at low, medium, and high reconstruction strengths. CT number, noise, noise reduction rate, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were measured and calculated within the region of interest (ROI) on subcutaneous fat, bilateral renal cortices, renal medulla, renal arteries, and adrenal glands. For qualitative analyses, the differentiation of the renal cortex and medulla, conspicuity of the adrenal gland boundary, sharpness, artifacts, and subjective noise were assessed. The overall image quality was calculated on a scale from 0 (worst) to 15 (best) based on the five values above and the score≥9 was acceptable. RESULTS: CT number does not significantly differ between the reconstruction datasets. Noise does not significantly differ between ASiR-V 30% and DLIR-L, but it is significantly lower using ASiR-V 70%, DLIR-M, and DLIR-H. The noise reduction rate relative to ASiR-V 30% is significantly different between the DLIR groups and ASiR-V 70%, and DLIR-H yields the highest noise reduction rate (61.6%). SNR and CNR are higher for DLIR-M, DLIR-H, and ASiR-V 70% than for ASiR-V 30% and DLIR-L. DLIR-H shows the best SNR and CNR. The overall image quality yields the same pattern for DLIR-H, with the highest score. Percentages of cases with overall image quality score≥9 are 100% (DLIR-H), 94.23% (DLIR-M), 90.38% (ASiR-V70%), 67.31% (DLIR-L), and 63.46% (ASiR-V30%), respectively. CONCLUSIONS: DLIR significantly improved the objective and subjective image quality of renal and adrenal CTs, yielding superior noise reduction compared with ASiR-V.


Assuntos
Aprendizado Profundo , Algoritmos , Humanos , Processamento de Imagem Assistida por Computador , Doses de Radiação , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Tomografia Computadorizada por Raios X/métodos
19.
Entropy (Basel) ; 24(8)2022 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-36010797

RESUMO

At present, electron optical simulator (EOS) takes a long time to solve linear FEM systems. The algebraic multigrid preconditioned conjugate gradient (AMGPCG) method can improve the efficiency of solving systems. This paper is focused on the implementation of the AMGPCG method in EOS. The aggregation-based scheme, which uses two passes of a pairwise matching algorithm and the K-cyle scheme, is adopted in the aggregation-based algebraic multigrid method. Numerical experiments show the advantages and disadvantages of the AMG algorithm in peak memory and solving efficiency. The AMGPCG is more efficient than the iterative methods used in the past and only needs one coarsening when EOS computes the particle motion trajectory.

20.
J Cell Mol Med ; 25(8): 3724-3734, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33724642

RESUMO

Several studies reported the role of endoplasmic reticulum stress (ERS) in vascular calcification. High-mobility group box-1 (HMGB-1) plays a substantial role in diabetes and its complications. However, relatively little information is available regarding the association between HMGB-1 and calcification, and the underlying mechanism has still remained elusive. Therefore, in the present study, we attempted to indicate whether HMGB-1 could promote vascular calcification via ERS in diabetes. After induction of diabetes by Streptozotocin (STZ), mice were treated with glycyrrhizin (Gly) or 4-phenylbutyrate (4-PBA). Mineral deposition was confirmed by reverse transcription-polymerase chain reaction (RT-PCR) and calcium assay. In cell experiments, calcification of vascular smooth muscle cells (VSMCs) was performed with Alizarin Red staining, alkaline phosphatase (ALP) activity and RT-PCR. Expression and location of HMGB-1 in aortic tissue were detected by Western blotting, immunocytochemistry (ICC) and immunohistochemistry (IHC). Diabetic mice demonstrated increased HMGB-1 expression, ERS and vascular calcification. However, inhibition of HMGB-1 with Gly or inhibition of ERS with 4-PBA ameliorated the enhanced vascular calcification and ERS in diabetic mice. In vitro experiments unveiled that inhibition of HMGB-1 attenuated advanced glycation end products (AGEs)-induced ERS in VSMCs. In addition, AGEs promoted translocation and secretion of HMGB-1 in VSMCs, which was reversed by 4-PBA. Moreover, VSMCs exhibited increased mineralization and osteogenic gene expressions in response to HMGB-1 and AGEs. However, inhibition of ERS with 4-PBA partially, although noticeably, attenuated VSMC calcification induced by HMGB-1. Thus, diabetes induced translocation and secretion of HMGB-1 via ERS, which resulted in calcification in diabetic mice and in AGEs-treated VSMCs.


Assuntos
Diabetes Mellitus Experimental/complicações , Estresse do Retículo Endoplasmático , Proteína HMGB1/metabolismo , Calcificação Vascular/patologia , Animais , Proteína HMGB1/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Calcificação Vascular/etiologia , Calcificação Vascular/metabolismo
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