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1.
AJR Am J Roentgenol ; : 1-8, 2020 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-32228328

RESUMO

OBJECTIVE. The clumpy artifact has a high misdiagnosis rate, but the artifact has not been well studied. The aims of this study were to evaluate the frequency and location of clumpy artifacts, the rate of misdiagnosis of clumpy artifacts as gout, and the effects of raising the minimum attenuation value and using a selective photon shield in dual-energy CT (DECT). MATERIALS AND METHODS. Forty patients without gout who underwent foot and ankle DECT were enrolled in this study. Images in both sets were randomly assigned a minimum attenuation of 130 HU or 150 HU. Three radiologists independently checked all images for presence, volume, and location of green color-coded pixelation and graded their findings according to a 4-point confidence scale, frequency, and volume. Misdiagnosis rate and misdiagnosis score were compared using the Wilcoxon signed rank and McNemar tests. RESULTS. In set 1, the frequency of clumpy artifacts in DECT with the minimum attenuation set to 130 HU and 150 HU were 81% and 68%, respectively. For all three readers, the misdiagnosis rate and misdiagnosis score decreased when changing the minimum attenuation from 130 HU to 150 HU. In set 2, with the minimum attenuation set to 130 HU, the frequency of the clumpy artifact was 44%; with the minimum attenuation set to 150 HU, no clumpy artifacts were seen. CONCLUSION. Clumpy artifacts occurred frequently in DECT without a tin filter. Setting the minimum attenuation to the higher value of 150 HU reduced the frequency of clumpy artifacts, and adding a tin filter to DECT greatly reduced their occurrence.

2.
iScience ; 23(3): 100926, 2020 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-32146324

RESUMO

Long decoherence time is a key consideration for molecular magnets in the application of the quantum computation. Although previous studies have shown that the local symmetry of spin carriers plays a crucial part in the spin-lattice relaxation process, its role in the spin decoherence is still unclear. Herein, two nine-coordinated capped square antiprism neodymium moieties [Nd(CO3)4H2O]5- with slightly different local symmetries, C1 versus C4 (1 and 2), are reported, which feature in the easy-plane magnetic anisotropy as shown by the high-frequency electron paramagnetic resonance (HF-EPR) studies. Detailed analysis of the relaxation time suggests that the phonon bottleneck effect is essential to the magnetic relaxation in the crystalline samples of 1 and 2. The 240 GHz Pulsed EPR studies show that the higher symmetry results in longer decoherence times, which is supported by the first principle calculations.

3.
J Am Chem Soc ; 142(6): 3240-3245, 2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-31973518

RESUMO

Due to the intriguing chemical variability and structure-property flexibility, molecular materials with striking multifunctional characteristics, including tunable physical, chemical, optical, and electronic properties, have aroused wide attention. Recently, great advances have also been made in designing molecular ferroelastics with optoelectronic properties. However, the band gaps of the most typical ferroelastics are far in excess of 2.0 eV, which severely hinder their further applications. And this corresponds to the inherent incompatibility of ferroelastics. Herein we report an organometallic compound, ferrocenium tetrachloroferrate (1), undergoing a ferroelastic phase transition at 407.7 K with a large spontaneous strain of 0.1088. To the best of our knowledge, this is the first molecular ferroelastic with such a high Curie temperature (Tc) and narrow band gap of 1.61 eV. UV-vis absorption spectra and density-functional theory (DFT) calculation confirm this band gap. The band gap of 1 is determined by both the ferrocenium and the tetrachloroferrate components. The ideal semiconducting characteristic makes a breakthrough in the inherent incompatibility with ferroelastics. This will inspire an intriguing and further research in molecular ferroelastics with ideal semiconductor characteristics and hold great potential for the utilization in optoelectronic devices, especially the photovoltaic applications.

4.
Dalton Trans ; 49(7): 2159-2167, 2020 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-31994553

RESUMO

The effect of screening the CoII moment of monomeric [CoIIL2(H2O)] (L = 8-hydroxyquinaldine), having a trigonal bipyramid coordination, by diamagnetic Zn in CoxZn1-x solid solutions on its magnetic relaxation was explored using ac-susceptibility, high-field electron-spin-resonance measurements and CASPT2 calculations. The retention of the crystal structure for all the solid solutions was demonstrated using single crystal diffraction. The dc-magnetization and theoretical fittings of the susceptibility for Co1 and Co0.1Zn0.9 gave a large zero-field-splitting (ZFS) D of 50 ± 6 cm-1, and very weak dipole interaction between the nearest neighbors, while EPR and calculations confirmed the positive sign of the axial component (D). Consistent parameters were obtained from experiments and theory. Importantly, only field-induced relaxation was observed for the samples with less than 50% Co and a gradual change in the barrier energy to moment reversal and relaxation times was observed between 11% and 20% Co, while both were enhanced for higher dilutions. The results establish a clear barrier for extending the longevity of the magnetism for this type of single-ion species by lowering the intramolecular interactions. The results suggest that the magnetic interaction persists up to the second sphere, that is, for a dilution of 1 in 9 (11% Co). Importantly, this method is applicable to all single-ion magnet systems, that is, the optimum dilution concentration to restrain the dipole field can be given only by the single crystal structure.

5.
Dalton Trans ; 49(7): 2063-2067, 2020 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-31998908

RESUMO

Two mononuclear, seven-coordinate Co(ii) and Fe(ii) complexes [CoII(BPA-TPA)](BF4)2 (1-Co) and [FeII(BPA-TPA)](ClO4)2 (2-Fe) with a capped trigonal prismatic coordination geometry have been synthesized from the pentapyridyldiamine (BPA-TPA) ligand. 1-Co exhibits easy plane anisotropy in which slow magnetic relaxation is observed under a 1.0 kOe dc field. It is the first example of a single-ion magnet (SIM) of a 3d transition metal ion with a capped trigonal prismatic configuration. 2-Fe is not a SIM at 1.8 K.

6.
Dalton Trans ; 2020 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-31976497

RESUMO

By changing the stoichiometric ratios, the one-pot reaction of the glycinehydroxamic acid (H2glyha) ligand with copper(ii) and lanthanide(iii) salts in the presence of diamagnetic [Na2{Fe(CN)5(NO)}] led to two series of isostructural complexes, which can be designated as heterotrimetallic dimeric clusters [{LnCu5(glyha)5}{Fe(CN)5(NO)}(H2O)4]2·xNO3·yH2O (x = 2, y = 11 for La (1), x = 2, y = 11 for Pr (2), and x = 2, y = 11 for Nd (3)) and heterotetrametallic coordination polymers [Na{LnCu5(glyha)5}{Fe(CN)5(NO)}2(H2O)x·yH2O]n (x = 6, y = 4 for Sm (4), x = 6, y = 0 for Gd (5), x = 6, y = 4 for Tb (6), x = 5, y = 5 Dy (7), and x = 6, y = 4 for Ho (8)). Each molecular structure contains LnIII[15-metallacrown-5] nodes and diamagnetic [Fe(CN)5(NO)]2- linkers. The resulting products demonstrate diversified structural frameworks due to the radius effect of LnIII ions and different bridging fashions of diamagnetic [Fe(CN)5(NO)]2- linkers. An analysis of magnetic susceptibilities reveals that 7 exhibits ferromagnetic coupling between CuII and DyIII ions and field-induced SMM behavior.

7.
Artigo em Inglês | MEDLINE | ID: mdl-31931556

RESUMO

Objective: To generate synthetic spine magnetic resonance (MR) images from spine computed tomography (CT) using generative adversarial networks (GANs), as well as to determine the similarities between synthesized and real MR images. Methods: GANs were trained to transform spine CT image slices into spine magnetic resonance T2 weighted (MRT2) axial image slices by combining adversarial loss and voxel-wise loss. Experiments were performed using 280 pairs of lumbar spine CT scans and MRT2 images. The MRT2 images were then synthesized from 15 other spine CT scans. To evaluate whether the synthetic MR images were realistic, two radiologists, two spine surgeons, and two residents blindly classified the real and synthetic MRT2 images. Two experienced radiologists then evaluated the similarities between subdivisions of the real and synthetic MRT2 images. Quantitative analysis of the synthetic MRT2 images was performed using the mean absolute error (MAE) and peak signal-to-noise ratio (PSNR). Results: The mean overall similarity of the synthetic MRT2 images evaluated by radiologists was 80.2%. In the blind classification of the real MRT2 images, the failure rate ranged from 0% to 40%. The MAE value of each image ranged from 13.75 to 34.24 pixels (mean, 21.19 pixels), and the PSNR of each image ranged from 61.96 to 68.16 dB (mean, 64.92 dB). Conclusion: This was the first study to apply GANs to synthesize spine MR images from CT images. Despite the small dataset of 280 pairs, the synthetic MR images were relatively well implemented. Synthesis of medical images using GANs is a new paradigm of artificial intelligence application in medical imaging. We expect that synthesis of MR images from spine CT images using GANs will improve the diagnostic usefulness of CT. To better inform the clinical applications of this technique, further studies are needed involving a large dataset, a variety of pathologies, and other MR sequence of the lumbar spine.

8.
Biochem Biophys Res Commun ; 522(3): 731-735, 2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-31791585

RESUMO

Rheumatoid arthritis (RA) is a highly inflammatory autoimmune disease. Although proinflammatory cytokines, including tumor necrosis factor (TNF) and interleukin (IL)-6, play a key role in the pathogenesis of RA, the causes of chronic inflammation are not fully understood. Here, we report that protein phosphatase magnesium-dependent 1A (PPM1A) levels were increased in RA synovial fluid compared with osteoarthritis (OA) synovial fluid and positively correlated with TNF levels. In addition, PPM1A expression was increased in synovial tissue from RA patients and joint tissue from a mouse model of arthritis. Finally, extracellular PPM1A induced inflammation by stimulating macrophages to produce TNF through toll-like receptor 4 (TLR4) and myeloid differentiation primary response protein 88 (MyD88) signaling pathway. Our findings suggest that extracellular PPM1A may contribute to the pathogenesis of RA by functioning as a damage-associated molecular pattern (DAMP) to induce inflammation.

9.
Mol Neurobiol ; 57(1): 278-289, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31325023

RESUMO

Cerebral amyloid angiopathy (CAA) refers to pathological changes occurring in cerebral blood vessels caused by deposition of beta amyloid (Aß) protein. However, the mechanisms involved in the origin of Aß for the formation of CAA and its link to parenchymal amyloid depositions remained to be unraveled. Here, we found CAA and parenchymal plaques distributed separately instead of mingling with each other in the spinal cord of TgCRND8 mice. Parenchymal plaques predominantly located in the dorsal horn whereas CAA distributed in the ventral horn. We further found that the ratio of Aß40/Aß42 was significantly higher in the ventral than that in the dorsal by ELISA assay, suggesting that origin of Aß forming parenchymal plaques may be different from that of CAA in the spinal cord. This hypothesis was further demonstrated by the surgical methods which indicated eliminating parenchymal plaques did not alter CAA in the affected spinal cord. We also examined the ratio of Aß40/Aß42 in the cerebral spinal fluid (CSF) in order to identify the origin of the CAA formation, and found the Aß40/Aß42 ratio was similar to that of CAA formation in the ventral horn. We further demonstrated that CSF tracer distributed along ventral horn vessels, in exactly the same pattern as Aß deposition in CAA in ventral part of spinal cord. These findings verified the concept that CSF influx may act as a constant source for delivering Aß, and contribute to the growth of paraarterial deposits in CAA. Taken together, the results of the present study highlight the important role of the Aß40/Aß42 ratio in determining vascular versus parenchymal amyloid deposition. Unlike parenchymal plaques, Aß of CAA comes from CSF; thus, manipulation of CSF Aß could represent a novel strategy to treat CAA.

10.
Inorg Chem ; 59(4): 2111-2115, 2020 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-31397564

RESUMO

Reaction of the diazafluorenylidene-substituted phosphaalkene 1 with [Cp*2Ln][BPh4] (Ln = Dy, Tb, and Gd), followed by subsequent reduction with KC8, afforded complexes Cp*2Dy(N,N'-1) (2), Cp*2Tb(N,N'-1) (3), and Cp*2Gd(N,N'-1) (4) in moderate yields, in which the phosphaalkene moiety is in the radical-anion state. Complexes 2 and 3 represent the first lanthanide metal complexes of a heavy main-group element-based radical. They have been characterized by single-crystal X-ray diffraction, UV/vis spectroscopy, and superconducting quantum interference device measurements. The magnetic studies reveal that the phosphorus-radical centers have a quite weak antiferromagnetic interaction with the lanthanide ions in 2-4. Furthermore, complex 2 shows slow magnetic relaxation behavior.

11.
Biol Pharm Bull ; 43(3): 409-417, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31875578

RESUMO

Forest bathing is suggested to have beneficial effects on various aspects of human health. Terpenes, isoprene based-phytochemicals emitted from trees, are largely responsible for these beneficial effects of forest bathing. Although the therapeutic effects of terpenes on various diseases have been revealed, their effects on neuronal health have not yet been studied in detail. Here, we screened 16 terpenes that are the main components of Korean forests using Drosophila Alzheimer's disease (AD) models to identify which terpenes have neuroprotective effects. Six out of the 16 terpenes, ρ-cymene, limonene (+), limonene (-), linalool, α-pinene (+), and ß-pinene (-), partially suppressed the beta amyloid 42 (Aß42)-induced rough eye phenotype when fed to Aß42-expressing flies. Among them, limonene (+) restored the decreased survival of flies expressing Aß42 in neurons during development. Limonene (+) treatment did not affect Aß42 accumulation and aggregation, but did cause to decrease cell death, reactive oxygen species levels, extracellular signal-regulated kinase phosphorylation, and inflammation in the brains or the eye imaginal discs of Aß42-expressing flies. This neuroprotective effect of limonene (+) was not associated with autophagic activity. Our results suggest that limonene (+) has a neuroprotective function against the neurotoxicity of Aß42 and, thus, is a possible therapeutic reagent for AD.

12.
Sci Total Environ ; 705: 135912, 2020 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-31846819

RESUMO

High energy gamma radiation is potentially hazardous to organisms, including aquatic invertebrates. Although extensively studied in a number of invertebrate species, knowledge on effects induced by gamma radiation is to a large extent limited to the induction of oxidative stress and DNA damage at the molecular/cellular level, or survival, growth and reproduction at the organismal level. As the knowledge of causal relationships between effects occurring at different levels of biological organization is scarce, the ability to provide mechanistic explanation for observed adverse effects is limited, and thus development of Adverse Outcome Pathways (AOPs) and larger scale implementation into next generation hazard and risk predictions is restricted. The present study was therefore conducted to assess the effects of high-energy gamma radiation from cobalt-60 across multiple levels of biological organization (i.e., molecular, cellular, tissue, organ and individual) and characterize the major toxicity pathways leading to impaired reproduction in the model freshwater crustacean Daphnia magna (water flea). Following gamma exposure, a number of bioassays were integrated to measure relevant toxicological endpoints such as gene expression, reactive oxygen species (ROS), lipid peroxidation (LPO), neutral lipid storage, adenosine triphosphate (ATP) content, apoptosis, ovary histology and reproduction. A non-monotonic pattern was consistently observed across the levels of biological organization, albeit with some variation at the lower end of the dose-rate scale, indicating a complex response to radiation doses. By integrating results from different bioassays, a novel pathway network describing the key toxicity pathways involved in the reproductive effects of gamma radiation were proposed, such as DNA damage-oocyte apoptosis pathway, LPO-ATP depletion pathway, calcium influx-endocrine disruption pathway and DNA hypermethylation pathway. Three novel AOPs were proposed for oxidative stressor-mediated excessive ROS formation leading to reproductive effect, and thus introducing the world's first AOPs for non-chemical stressors in aquatic invertebrates.

13.
Eur Radiol ; 2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-31822976

RESUMO

OBJECTIVES: To evaluate the diagnostic performance of dual-energy CT with water-hydroxyapatite (HAP) imaging for bone marrow edema in patients with non-traumatic hip pain. METHODS: Forty patients (mean age, 58 years; 16 male and 24 female) who underwent rapid kVp-switching dual-energy CT and MRI within 1 month between April 2018 and February 2019 with hip pain but no trauma were enrolled. Two radiologists retrospectively evaluated 80 hip joints for the presence, extent (femoral head involved, head and neck, and head to intertrochanter), and severity (mild edema, moderate, severe) of bone marrow edema on dual-energy water-HAP images. Water mass density (mg/cm3) on water-HAP images was determined with region of interest-based quantitative analysis. MRI served as the standard of reference. RESULTS: Sensitivity, specificity, and accuracy of readers 1 and 2 for the identification of bone marrow edema in water-HAP images were 85% and 85%, 93% and 73%, and 89% and 79%, respectively. The area under the receiver operating characteristic curve was 0.96 for reader 1 and 0.91 for reader 2 for differentiation of the presence of edema from no edema. The optimal water mass density to classify the presence of edema for reader 1 was 951 mg/cm3 with 93% sensitivity and 93% specificity and for reader 2 was 957 mg/cm3 with 80% sensitivity and 80% specificity. The more severe the edema, the higher was the mean water density value (p < 0.035). CONCLUSION: Dual-energy water-HAP images showed good diagnostic performance for bone marrow edema in patients with non-traumatic hip pain. KEY POINTS: • Dual-energy water-HAP imaging depicts bone marrow edema in patients with non-traumatic hip pain and may serve as an alternative to MRI in select patients. • A cutoff value of 951 mg/cm 3mean water mass density results in 93% sensitivity and 93% specificity for the detection of bone marrow edema. • The more severe the bone marrow edema, the higher the mean water density value.

14.
Medicine (Baltimore) ; 98(50): e18236, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31852088

RESUMO

BACKGROUND: This study aims to assess the impact of contrast-enhanced transcranial Doppler ultrasound (cTCD) diagnosis for young adult with cryptogenic stroke (CS). METHODS: This study will analyze data from case-controlled studies investigating the impact of cTCD diagnosis for young adult with CS. A comprehensive literature search will be performed from PUBMED, EMBASE, Cochrane Library, Web of Science, Cumulative Index to Nursing and Allied Health Literature, Chinese Biomedical Literature Database, China National Knowledge Infrastructure, and Wanfang Data from their inceptions up to the August 1, 2019. All databases will be searched with no language limitations. Two researchers will independently carry out study selection, data collection, and study quality assessment. Any discrepancies between two researchers will be solved by a third researcher. We will apply RevMan 5.3 software and Stata 12.0 software for statistical analysis. RESULTS: Outcomes consist of sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio for determination of cTCD diagnosis for young adult with CS. CONCLUSION: The results of this study may summarize up-to-date evidence of cTCD diagnosis for young adult with CS. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42019145641.


Assuntos
Meios de Contraste/farmacologia , Acidente Vascular Cerebral/diagnóstico , Ultrassonografia Doppler Transcraniana/métodos , Humanos , Curva ROC , Reprodutibilidade dos Testes , Adulto Jovem
15.
Inorg Chem ; 58(21): 14440-14448, 2019 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-31626540

RESUMO

The magnetic properties of single-molecule magnets can be controlled by external conditions such as light, pressure, and temperature. Among these conditions, photochemical control is the best approach due to the accessibility and rapid conduction of light. In this work, an Er(III)-based complex with photoactive ligand bpe, [Er(nat)3·MeOH·bpe] (1, bpe = 1,2-bis(2-pyridyl)ethylene, nat = 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedione), was synthesized. The auxiliary ligand nat and cyclized ligand bpe stacked reasonably in the crystal structure. Two molecules of 1 experienced the [2, 2]-cycloaddition reaction under the UV irradiation in the solid state and [{Er(nat)3MeOH}2(tpcb)] (2, tpcb = tetrakis(4-pyridyl)cyclobutane) was produced. The slight change in the structure around Er(III) ions leads to the different magnetic properties, which illustrates the photochemical control of the magnetic properties of single-molecule magnets.

16.
Chem Commun (Camb) ; 55(85): 12873-12876, 2019 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-31599287

RESUMO

A brand new europium(iii) ß-diketonate complex undergoes a single-crystal-to-single-crystal transformation via [2+2] cycloaddition after UV irradiation, triggering strong Eu(iii) red emission turn-on, which is highly photostable even after 50 hours of irradiation. A photo-patterning process is successfully conducted for security printing application in materials science.

17.
Environ Epigenet ; 5(3): dvz016, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31528364

RESUMO

The water flea Daphnia magna is a keystone species in freshwater ecosystems and has been widely used as a model organism in environmental ecotoxicology. This aquatic crustacean is sensitive to environmental stressors and displays considerable plasticity in adapting to changing environmental conditions. Part of this plasticity may be due to epigenetic regulation of gene expression, including changes to DNA methylation and histone modifications. Because of the generally hypomethylated genome of this species, we hypothesized that the histone code may have an essential role in the epigenetic control and that histone modifications might be an early marker for stress. This study aims to characterize the epigenetic, transcriptional and phenotypic responses and their causal linkages in directly exposed adult (F0) Daphnia and peritoneal exposed neonates (F1) after a chronic (7-day) exposure to a sublethal concentration (10 mg/l) of 5-azacytidine, a well-studied vertebrate DNA methylation inhibitor. Exposure of the F0 generation significantly reduced the cumulative fecundity, accompanied with differential expression of genes in the one-carbon-cycle metabolic pathway. In the epigenome of the F0 generation, a decrease in global DNA methylation, but no significant changes on H3K4me3 or H3K27me3, were observed. In the F1 offspring generation, changes in gene expression, a significant reduction in global DNA methylation and changes in histone modifications were identified. The results indicate that exposure during adulthood may result in more pronounced effects on early development in the offspring generation, though interpretation of the data should be carefully done since both the exposure regime and developmental period is different in the two generations examined. The obtained results improve our understanding of crustacean epigenetics and the tools developed may promote use of epigenetic markers in hazard assessment of environmental stressors.

18.
Dalton Trans ; 48(35): 13472-13482, 2019 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-31454007

RESUMO

Four chair-like hexanuclear Fe-Ln complexes containing mixed organic ligands, namely, [Fe4Ln2{(py)2CO2}4(pdm)2(NO3)2(H2O)2Cl4]·xCH3CN·yH2O (Ln = GdIII (1, x = 1, y = 0), DyIII (2, x = 1, y = 1), HoIII (3, x = 0, y = 2), and ErIII (4, x = 1, y = 3); (py)2CO2H2 = the gem-diol form of di-2-pyridyl ketone and pdmH2 = 2,6-pyridinedimethanol) have been obtained by employing di-2-pyridyl ketone and 2,6-pyridinedimethanol reacting with FeCl3 and Ln(NO3)3 in MeCN. The structures of 1-4 are similar to each other except for the number of lattice solvent molecules. Four FeIII and two LnIII in these complexes comprise a chair-like core with the "body" constructed by four FeIII ions and the "end" constructed by two LnIII ions. Among the four compounds, 2 shows field-induced single molecule magnet behavior as revealed by ac magnetic susceptibility studies, with the effective energy barrier and the pre-exponential factor of 22.07 K and 8.44 × 10-7 s, respectively. Ab initio calculations indicated that, among 2_Dy, 3_Ho and 4_Er fragments, the energy gap between the lowest two spin-orbit states for 2_Dy is the largest, while the tunneling gap for 2 is the smallest. These might be the reasons for complex 2 exhibiting SMM behavior. Additionally, the orientations of the magnetic anisotropy of DyIII in 2 were obtained by electrostatic calculations and ab initio calculations, both indicating that the directions of the main magnetic axis of Dy1 ions are almost aligned along Dy1-O5 (O5 from the pdm2- ligand).

19.
Sci Rep ; 9(1): 12434, 2019 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-31455835

RESUMO

In this work, the two-dimensional profile of the light transmission through a prism-like metallic film sample of Au was measured at a wavelength of 632.8 nm in the visible intraband transition region to verify that, beyond the possible mechanisms of overcoming the diffraction limit, a strongly nonuniform optical absorption path length of the light traveling in the metal could induce a lensing effect, thereby narrowing the image of an object. A set of prism-like Au samples with different angles was prepared and experimentally investigated. Due to the nonuniform paths of the light traveling in the Au samples, lens-effect-like phenomena were clearly observed that reduced the imaged size of the beam spot with decreasing light intensity. The experimental measurements presented in the work may provide new insight to better understand the light propagation behavior at a metal/dielectric interface.

20.
Sci Rep ; 9(1): 10211, 2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31308474

RESUMO

Optical spectrometers play a key role in acquiring rich photonic information in both scientific research and a wide variety of applications. In this work, we present a new spectrometer with an ultrahigh resolution of better than 0.012 nm/pixel in the 170-600 nm spectral region using a grating-integrated module that consists of 19 subgratings without any moving parts. By using two-dimensional (2D) backsideilluminated complementary metal-oxide-semiconductor (BSI-CMOS) array detector technology with 2048 × 2048 pixels, a high data acquisition speed of approximately 25 spectra per second is achieved. The physical photon-sensing size of the detector along the one-dimensional wavelength direction is enhanced by a factor of 19 to approximately 428 mm, or 38912 pixels, to satisfy the requirement of seamless connection between two neighboring subspectral regions without any missing wavelengths throughout the entire spectral region. As tested with a mercury lamp, the system has advanced performance capabilities characterized by the highest k parameter reported to date, being approximately 3.58 × 104, where k = (working wavelength region)/(pixel resolution). Data calibration and analysis as well as a method of reducing background noise more efficiently are also discussed. The results presented in this work will stimulate further research on precision spectrometers based on advanced BSI-CMOS array detectors in the future.

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