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1.
Nature ; 583(7818): 785-789, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32690938

RESUMO

An exciton is the bosonic quasiparticle of electron-hole pairs bound by the Coulomb interaction1. Bose-Einstein condensation of this exciton state has long been the subject of speculation in various model systems2,3, and examples have been found more recently in optical lattices and two-dimensional materials4-9. Unlike these conventional excitons formed from extended Bloch states4-9, excitonic bound states from intrinsically many-body localized states are rare. Here we show that a spin-orbit-entangled exciton state appears below the Néel temperature of 150 kelvin in NiPS3, an antiferromagnetic van der Waals material. It arises intrinsically from the archetypal many-body states of the Zhang-Rice singlet10,11, and reaches a coherent state assisted by the antiferromagnetic order. Using configuration-interaction theory, we determine the origin of the coherent excitonic excitation to be a transition from a Zhang-Rice triplet to a Zhang-Rice singlet. We combine three spectroscopic tools-resonant inelastic X-ray scattering, photoluminescence and optical absorption-to characterize the exciton and to demonstrate an extremely narrow excitonic linewidth below 50 kelvin. The discovery of the spin-orbit-entangled exciton in antiferromagnetic NiPS3 introduces van der Waals magnets as a platform to study coherent many-body excitons.

2.
Nano Lett ; 23(22): 10189-10195, 2023 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-37931216

RESUMO

The unique discovery of the magnetic exciton in van der Waals antiferromagnet NiPS3 arises between two quantum many-body states of a Zhang-Rice singlet excited state and a Zhang-Rice triplet ground state. Simultaneously, the spectral width of photoluminescence originating from this exciton is exceedingly narrow as 0.4 meV. These extraordinary properties, including the extreme coherence of the magnetic exciton in NiPS3, beg many questions. We studied doping effects using Ni1-xCdxPS3 using two experimental techniques and theoretical studies. Our experimental results show that the magnetic exciton is drastically suppressed upon a few % Cd doping. All this happens while the width of the exciton only gradually increases and the antiferromagnetic ground state is robust. These results highlight the lattice uniformity's hidden importance as a prerequisite for coherent magnetic exciton. Finally, an exciting scenario emerges: the broken charge transfer forbids the otherwise uniform formation of the coherent magnetic exciton in (Ni,Cd)PS3.

3.
Ann Rheum Dis ; 81(6): 815-822, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35241426

RESUMO

OBJECTIVE: To evaluate the efficacy and safety of an oral selective tyrosine kinase 2 (TYK2) inhibitor, deucravacitinib, in patients with active psoriatic arthritis (PsA). METHODS: In this double-blind, phase II trial, 203 patients with PsA were randomised 1:1:1 to placebo, deucravacitinib 6 mg once a day or 12 mg once a day. The primary endpoint was American College of Rheumatology-20 (ACR-20) response at week 16. RESULTS: ACR-20 response was significantly higher with deucravacitinib 6 mg once a day (52.9%, p=0.0134) and 12 mg once a day (62.7%, p=0.0004) versus placebo (31.8%) at week 16. Both deucravacitinib doses resulted in significant improvements versus placebo (p≤0.05) in the multiplicity-controlled secondary endpoints of change from baseline in Health Assessment Questionnaire-Disability Index and Short Form-36 Physical Component Summary score and in Psoriasis Area and Severity Index-75 response. Improvements were also seen in multiple exploratory endpoints with deucravacitinib treatment. The most common adverse events (AEs) (≥5%) in deucravacitinib-treated patients were nasopharyngitis, upper respiratory tract infection, sinusitis, bronchitis, rash, headache and diarrhoea. There were no serious AEs and no occurrence of herpes zoster, opportunistic infections and major adverse cardiovascular events, or differences versus placebo in mean changes in laboratory parameters with deucravacitinib treatment. CONCLUSIONS: Treatment with the selective TYK2 inhibitor deucravacitinib was well tolerated and resulted in greater improvements than placebo in ACR-20, multiplicity-controlled secondary endpoints and other exploratory efficacy measures in patients with PsA. Larger trials over longer periods of time with deucravacitinib are warranted to confirm its safety profile and benefits in PsA. TRIAL REGISTRATION NUMBER: NCT03881059.


Assuntos
Antirreumáticos , Artrite Psoriásica , Antirreumáticos/uso terapêutico , Artrite Psoriásica/induzido quimicamente , Artrite Psoriásica/tratamento farmacológico , Método Duplo-Cego , Compostos Heterocíclicos , Humanos , Índice de Gravidade de Doença , TYK2 Quinase , Resultado do Tratamento
4.
Int J Mol Sci ; 19(2)2018 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-29470423

RESUMO

Citrus fruits contain various types of flavonoids with powerful anti-aging and photoprotective effects on the skin, and have thus been attracting attention as potential, efficacious skincare agents. Here, we aimed to investigate the chemical composition of Citrus unshiu and its protective effects on photoaging. We isolated and identified a bioactive compound, 3,5,6,7,8,3',4'-heptamethoxyflavone (HMF), from C. unshiu peels using ethanol extraction and hexane fractionation. HMF inhibited collagenase activity and increased type I procollagen content in UV-induced human dermal fibroblast neonatal (HDFn) cells. HMF also suppressed the expression of matrix metalloproteinases 1 (MMP-1) and induced the expression of type I procollagen protein in UV-induced HDFn cells. Additionally, HMF inhibited ultraviolet B (UVB)-induced phosphorylation of the mitogen-activated protein kinases (MAPK) cascade signaling components-ERK, JNK, and c-Jun-which are involved in the induction of MMP-1 expression. Furthermore, HMF affected the TGF-ß/Smad signaling pathway, which is involved in the regulation of type I procollagen expression. In particular, HMF induced Smad3 protein expression and suppressed Smad7 protein expression in UV-induced HDFn cells in a dose-dependent manner. These findings suggest a role for Citrusunshiu in the preparation of skincare products in future.


Assuntos
Citrus/química , Colágeno Tipo I/biossíntese , Colagenases/metabolismo , Derme/citologia , Fibroblastos/metabolismo , Flavonoides/farmacologia , Morte Celular/efeitos dos fármacos , Células Cultivadas , Fibroblastos/efeitos dos fármacos , Flavonoides/química , Humanos , Recém-Nascido , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Proteína Smad3/metabolismo , Proteína Smad7/metabolismo
5.
Int J Mol Sci ; 17(3): 353, 2016 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-27005618

RESUMO

Corynebacterium glutamicum is widely used for amino acid production. In the present study, 543 genes showed a significant change in their mRNA expression levels in L-lysine-producing C. glutamicum ATCC21300 than that in the wild-type C. glutamicum ATCC13032. Among these 543 differentially expressed genes (DEGs), 28 genes were up- or downregulated. In addition, 454 DEGs were functionally enriched and categorized based on BLAST sequence homologies and gene ontology (GO) annotations using the Blast2GO software. Interestingly, NCgl0071 (bioB, encoding biotin synthase) was expressed at levels ~20-fold higher in the L-lysine-producing ATCC21300 strain than that in the wild-type ATCC13032 strain. Five other genes involved in biotin metabolism or transport--NCgl2515 (bioA, encoding adenosylmethionine-8-amino-7-oxononanoate aminotransferase), NCgl2516 (bioD, encoding dithiobiotin synthetase), NCgl1883, NCgl1884, and NCgl1885--were also expressed at significantly higher levels in the L-lysine-producing ATCC21300 strain than that in the wild-type ATCC13032 strain, which we determined using both next-generation RNA sequencing and quantitative real-time PCR analysis. When we disrupted the bioB gene in C. glutamicum ATCC21300, L-lysine production decreased by approximately 76%, and the three genes involved in biotin transport (NCgl1883, NCgl1884, and NCgl1885) were significantly downregulated. These results will be helpful to improve our understanding of C. glutamicum for industrial amino acid production.


Assuntos
Biotina/biossíntese , Corynebacterium glutamicum/genética , Genes Bacterianos , Lisina/metabolismo , Transcriptoma , Biotina/genética , Corynebacterium glutamicum/metabolismo
6.
Int J Mol Sci ; 17(11)2016 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-27801787

RESUMO

Ganoderma lucidum, a species of the Basidiomycetes class, has been attracting international attention owing to its wide variety of biological activities and great potential as an ingredient in skin care cosmetics including "skin-whitening" products. However, there is little information available on its inhibitory effect against tyrosinase activity. Therefore, the objectives of this study were to investigate the chemical composition of G. lucidum and its inhibitory effects on melanogenesis. We isolated the active compound from G. lucidum using ethanol extraction and ethyl acetate fractionation. In addition, we assayed its inhibitory effects on tyrosinase activity and melanin biosynthesis in B16F10 melanoma cells. In this study, we identified a bioactive compound, ganodermanondiol, which inhibits the activity and expression of cellular tyrosinase and the expression of tyrosinase-related protein-1 (TRP-1), TRP-2, and microphthalmia-associated transcription factor (MITF), thereby decreasing melanin production. Furthermore, ganodermanondiol also affected the mitogen-activated protein kinase (MAPK) cascade and cyclic adenosine monophosphate (cAMP)-dependent signaling pathway, which are involved in the melanogenesis of B16F10 melanoma cells. The finding that ganodermanondiol from G. lucidum exerts an inhibitory effect on tyrosinase will contribute to the use of this mushroom in the preparation of skin care products in the future.


Assuntos
Lanosterol/análogos & derivados , Melaninas/biossíntese , Melanoma Experimental/tratamento farmacológico , Reishi/química , Animais , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Interferon Tipo I/biossíntese , Interferon Tipo I/genética , Lanosterol/administração & dosagem , Lanosterol/química , Melanócitos/efeitos dos fármacos , Melanócitos/metabolismo , Melanoma Experimental/metabolismo , Melanoma Experimental/patologia , Camundongos , Fator de Transcrição Associado à Microftalmia/biossíntese , Fator de Transcrição Associado à Microftalmia/genética , Monofenol Mono-Oxigenase/antagonistas & inibidores , Fosforilação , Plantas Medicinais/química , Proteínas da Gravidez/biossíntese , Proteínas da Gravidez/genética
7.
Neurobiol Dis ; 60: 1-10, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23969237

RESUMO

Parkinson's disease (PD) is a progressive neurodegenerative movement disorder caused by the death of dopaminergic neurons in the substantia nigra. Importantly, altered astrocyte and microglial functions could contribute to neuronal death in PD. In this study, we demonstrate a novel mechanism by which DJ-1 (PARK7), an early onset autosomal-recessive PD gene, negatively regulates inflammatory responses of astrocytes and microglia by facilitating the interaction between STAT1 and its phosphatase, SHP-1 (Src-homology 2-domain containing protein tyrosine phosphatase-1). Astrocytes and microglia cultured from DJ-1-knockout (KO) mice exhibited increased expression of inflammatory mediators and phosphorylation levels of STAT1 (p-STAT1) in response to interferon-gamma (IFN-γ) compared to cells from wild-type (WT) mice. DJ-1 deficiency also attenuated IFN-γ-induced interactions of SHP-1 with p-STAT1 and STAT1, measured 1 and 12h after IFN-γ treatment, respectively. Subsequent experiments showed that DJ-1 directly interacts with SHP-1, p-STAT1, and STAT1. Notably, DJ-1 bound to SHP-1 independently of IFN-γ, whereas the interactions of DJ-1 with p-STAT1 and STAT1 were dependent on IFN-γ. Similar results were obtained in brain slice cultures, where IFN-γ induced much stronger STAT1 phosphorylation and inflammatory responses in KO slices than in WT slices. Moreover, IFN-γ treatment induced neuronal damage in KO slices. Collectively, these findings suggest that DJ-1 may function as a scaffold protein that facilitates SHP-1 interactions with p-STAT1 and STAT1, thereby preventing extensive and prolonged STAT1 activation. Thus, the loss of DJ-1 function may increase the risk of PD by enhancing brain inflammation.


Assuntos
Astrócitos/metabolismo , Microglia/metabolismo , Proteínas Oncogênicas/metabolismo , Proteína Tirosina Fosfatase não Receptora Tipo 6/metabolismo , Fator de Transcrição STAT1/metabolismo , Animais , Anti-Inflamatórios/metabolismo , Encéfalo/metabolismo , Interferon gama/metabolismo , Camundongos , Camundongos Knockout , Peroxirredoxinas , Fosforilação , Proteína Desglicase DJ-1
8.
Ophthalmology ; 120(10): 2151-9, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23714321

RESUMO

OBJECTIVE: To compare participants' responses to Web-based and paper-and-pencil versions of an ophthalmic, patient-reported outcome (PRO) questionnaire. DESIGN: Questionnaire development. PARTICIPANTS: Matched subjects with ocular surface disease (OSD) (n = 68) and without OSD (controls, n = 50). METHODS: Subjects completed a standard, paper-and-pencil and a Web-based version of the same questionnaire in randomized order. The administered questionnaire included several ophthalmic PRO subscales: the National Eye Institute's (NEI's) Refractive Error Quality of Life Instrument's Clarity of Vision, Near Vision, Far Vision, Glare, Symptoms, Worry, and Satisfaction with Correction subscales; the Ocular Surface Disease Index's (OSDI's) Symptoms subscale; and the NEI's Visual Function Questionnaire's Driving subscale. Possible scores for each subscale ranged from 0 (no difficulty) to 100 (most difficulty). Agreement of subscale scores between modes of administration was assessed using the Bland-Altman approach and multivariable logistic regression. MAIN OUTCOME MEASURES: Subscale scores and an unweighted average total score for each mode of administration. RESULTS: Mean differences in scores between modes of administration ranged from -2.1 to +2.3 units. Although no differences were found to be statistically significant, the Worry and Satisfaction with Correction subscales approached statistical significance (P = 0.07 and 0.08, respectively). Although most subscale mean differences in score did not differ significantly by gender, age (≥40 vs. <40 years), disease status (OSD vs. control), order of administration, or time between completion of the questionnaires, women had slightly greater score differences than men for the Driving (P = 0.04) and Clarity of Vision (P = 0.03) subscales; those with OSD had greater score differences for Clarity of Vision than did controls (P = 0.0006); and those aged ≥40 years had slightly greater differences in OSDI Symptoms subscale than those aged <40 years (P = 0.04). CONCLUSIONS: To our knowledge, this Food and Drug Administration and NEI collaboration is the first study to evaluate the equivalence of Web-based and paper versions of ophthalmic PRO questionnaires. We found no evidence of clinically significant differences between scores obtained by the 2 modes for any of the examined subscales. A Web-based instrument should yield scores equivalent to those obtained by standard methods, providing a useful tool that may facilitate ophthalmic innovation. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.


Assuntos
Internet , Oftalmologia , Avaliação de Resultados em Cuidados de Saúde/métodos , Papel , Inquéritos e Questionários , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
9.
J Immunol ; 186(6): 3701-9, 2011 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-21317391

RESUMO

Chemokines play critical roles in inflammation by recruiting inflammatory cells to injury sites. In this study, we found that UDP induced expression of chemokines CCL2 (MCP-1) and CCL3 (MIP-1α) in microglia, astrocytes, and slice cultures by activation of P2Y(6). Interestingly, CCL2 was more highly expressed than CCL3. However, CCL2 synthesis kinetics in response to UDP differed in microglia and astrocytes; microglia rapidly produced small amounts of CCL2, whereas astrocytes continuously synthesized large amounts of CCL2, resulting in a high ultimate level of the chemokine. UDP-induced chemokine expression was reduced in the presence of a specific antagonist of P2Y(6) (MRS2578) or small interfering RNA directed against the P2Y(6) gene. Inhibition of phospholipase C and calcium increase, downstream signaling pathways of Gq-coupled P2Y(6), reduced UDP-induced chemokine expression. UDP activated two calcium-activated transcription factors, NFATc1 and c2. Furthermore, inhibitors of calcineurin (a phosphatase activating NFAT) and NFAT reduced UDP-induced chemokine synthesis. We also found, using a transmigration assay, that UDP-treated astrocytes recruited monocytes. These results suggest that UDP induces chemokine expression in microglia and astrocytes of the injured brain by activation of P2Y(6) receptors.


Assuntos
Astrócitos/imunologia , Astrócitos/metabolismo , Quimiocina CCL2/biossíntese , Quimiocina CCL3/biossíntese , Microglia/imunologia , Microglia/metabolismo , Receptores Purinérgicos P2/metabolismo , Difosfato de Uridina/fisiologia , Animais , Animais Recém-Nascidos , Astrócitos/patologia , Movimento Celular/imunologia , Células Cultivadas , Córtex Cerebral/imunologia , Córtex Cerebral/metabolismo , Córtex Cerebral/patologia , Microglia/patologia , Monócitos/imunologia , Técnicas de Cultura de Órgãos , Ratos , Ratos Sprague-Dawley , Difosfato de Uridina/metabolismo
10.
Healthcare (Basel) ; 11(11)2023 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-37297684

RESUMO

PURPOSE: At present, there is a controversy regarding the effect of dual-task training on improving the cognitive function of people with mild cognitive impairment (MCI). This study was to develop and verify the effects of the cognitive-physical dual-task training program on the executive function of older adults with MCI. METHOD: Participants were randomly allocated to the experimental group (EG) receiving cognitive-physical dual-task training (n = 21) or the control group (CG) receiving cognitive single-task training (n = 21). RESULTS: After 16 sessions for 8 weeks, the Korean version of the Executive Function Performance Task (EFPT-K), the Frontal Assessment Battery (FAB), and Korean version of the Instrumental Activities of Daily Living (K-IADL) tests were implemented to assess people's executive function and instrumental activities during daily living. As the result, there were no significant differences in general characteristics between both groups (p > 0.05). After 16 sessions, the EG showed greater improvements in the EFPT-K (p < 0.05; η2 = 0.133), the FAB (p < 0.001; η2 = 0.305), and the K-IADL (p < 0.01; η2 = 0.221) compared to those of the CG. CONCLUSION: These results indicate that cognitive-physical dual-task training is clinically beneficial to improve the executive function and daily instrumental activities of older adults with MCI. Cognitive-physical dual-task training is a promising intervention for older adults with MCI.

11.
ACS Omega ; 8(15): 14190-14196, 2023 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-37091409

RESUMO

We have conducted a terahertz spectroscopic study and a density functional theory analysis of the phonon dynamics of the layered van der Waals semiconductors Nb3Cl8 and Nb3I8. Several infrared-active phonon modes were observed in the terahertz region, and their frequencies were found to be in excellent agreement with our first-principles lattice dynamics calculations. For Nb3Cl8, the observed phonon spectra are consistent with a structural transition at 90 K from the high-temperature P3̅m1 phase to the low-temperature R3̅m phase. Also, our study confirmed that the structural and magnetic transitions were coupled in Nb3Cl8. For Nb3I8, which is nonmagnetic at and below room temperature, no significant temperature or magnetic field dependence was observed in the phonon spectra. Our study provides an intriguing connection between the structural properties and the paramagnetic-nonmagnetic transitions in Nb3Cl8 and Nb3I8.

12.
J Neuroinflammation ; 9: 100, 2012 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-22632146

RESUMO

BACKGROUND: Traumatic spinal cord injury (SCI) causes acute neuronal death followed by delayed secondary neuronal damage. However, little is known about how microenvironment regulating cells such as microglia, astrocytes, and blood inflammatory cells behave in early SCI states and how they contribute to delayed neuronal death. METHODS: We analyzed the behavior of neurons and microenvironment regulating cells using a contusion-induced SCI model, examining early (3-6 h) to late times (14 d) after the injury. RESULTS: At the penumbra region close to the damaged core (P1) neurons and astrocytes underwent death in a similar spatial and temporal pattern: both neurons and astrocytes died in the medial and ventral regions of the gray matter between 12 to 24 h after SCI. Furthermore, mRNA and protein levels of transporters of glutamate (GLT-1) and potassium (Kir4.1), functional markers of astrocytes, decreased at about the times that delayed neuronal death occurred. However, at P1 region, ramified Iba-1+ resident microglia died earlier (3 to 6 h) than neurons (12 to 24 h), and at the penumbra region farther from the damaged core (P2), neurons were healthy where microglia were morphologically activated. In addition, round Iba-1/CD45-double positive monocyte-like cells appeared after neurons had died, and expressed phagocytic markers, including mannose receptors, but rarely expressed proinflammatory mediators. CONCLUSION: Loss of astrocyte function may be more critical for delayed neuronal death than microglial activation and monocyte infiltration.


Assuntos
Astrócitos/patologia , Contusões/patologia , Progressão da Doença , Degeneração Neural/patologia , Neurônios/patologia , Traumatismos da Medula Espinal/patologia , Animais , Astrócitos/metabolismo , Proteínas de Ligação ao Cálcio/biossíntese , Contusões/metabolismo , Feminino , Proteínas dos Microfilamentos/biossíntese , Degeneração Neural/metabolismo , Neurônios/metabolismo , Ratos , Ratos Sprague-Dawley , Traumatismos da Medula Espinal/metabolismo , Fatores de Tempo
13.
Transfusion ; 51(5): 921-8, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21091958

RESUMO

BACKGROUND: Granulocyte donors routinely receive dexamethasone orally before donation. Steroids may increase the risk of posterior subcapsular cataract (PSC) formation. STUDY DESIGN AND METHODS: We recruited 100 granulocyte donors (four or more granulocyte donations; any number of platelet [PLT] donations) and 100 age- and sex-matched PLT donors (zero to three granulocyte donations, any number of PLT donations) to examine the risk of PSC. PSC was assessed by a masked ophthalmologist and reading center lens photograph gradings or medical record documentation of PSC as the reason for cataract extraction. RESULTS: Fourteen eyes of 10 granulocyte donors and five eyes of four PLT donors had PSCs (odds ratio [OR], 2.82; 95% confidence interval [CI], 0.83-9.61; p = 0.10). Risk of PSC increased with number of granulocyte donations: compared to zero to three donations (4.0%), the risk for four to nine, 10 to 19, and 20 or more donations was 8.6% (OR, 2.25; 95% CI, 0.31-13.99; p = 0.30), 9.5% (OR, 2.53; 95% CI, 0.44-14.20; p = 0.21), and 13.0% (OR, 3.60; 95% CI, 0.48-22.81; p = 0.11), respectively (p = 0.06 for trend). CONCLUSION: We did not demonstrate a statistically significant increased risk of PSC associated with granulocyte donation. However, although this makes a large risk unlikely, we cannot rule out a small to moderate risk and there is biologic plausibility that the steroid administration associated with granulocyte donation could be associated with PSC formation. Transfusion medicine professionals should advise granulocyte apheresis donors to maintain an appropriate frequency of eye examinations.


Assuntos
Catarata/epidemiologia , Citaferese/estatística & dados numéricos , Dexametasona/efeitos adversos , Granulócitos/transplante , Doadores de Tecidos/estatística & dados numéricos , Idoso , Citaferese/métodos , Feminino , Glucocorticoides/efeitos adversos , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Prevalência , Fatores de Risco , Voluntários/estatística & dados numéricos
14.
ACS Omega ; 6(21): 13802-13806, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-34095672

RESUMO

Terahertz spectroscopy can be utilized as an effective nondestructive identification tool for the study of artist's pigments. Consequently, extensive measurements have been conducted on representative pigment species, and a few terahertz spectral databases have been constructed. However, the reported spectra were often acquired from pigment samples mixed with polyethylene at room temperature with low resolution, which often led to low-quality spectra with unresolved overlapping lines further broadened due to thermal effects. Here, we present our study of vermilion (HgS, mercury sulfide) as an illustration of how we can overcome such difficulties by studying free-standing oil-paint samples at room temperature and then by performing low-temperature measurements on polyethylene-mixed samples to minimize line broadening due to thermal effects. Our results identify clearly resolved absorption peaks due to lattice vibrations of vermilion at 40.4, 44.5, and 89.9 cm-1 at 2 K. The temperature dependence of the peak shift and line broadening reveals anharmonic characteristics of these lattice vibrational modes. Our approach will definitely suggest new ways to improve and enhance existing terahertz spectral databases of ancient and modern pigments toward actual analysis, diagnosis, and conservation of heritage artworks.

15.
Nat Commun ; 12(1): 4837, 2021 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-34376692

RESUMO

Collective excitations of bound electron-hole pairs-known as excitons-are ubiquitous in condensed matter, emerging in systems as diverse as band semiconductors, molecular crystals, and proteins. Recently, their existence in strongly correlated electron materials has attracted increasing interest due to the excitons' unique coupling to spin and orbital degrees of freedom. The non-equilibrium driving of such dressed quasiparticles offers a promising platform for realizing unconventional many-body phenomena and phases beyond thermodynamic equilibrium. Here, we achieve this in the van der Waals correlated insulator NiPS3 by photoexciting its newly discovered spin-orbit-entangled excitons that arise from Zhang-Rice states. By monitoring the time evolution of the terahertz conductivity, we observe the coexistence of itinerant carriers produced by exciton dissociation and a long-wavelength antiferromagnetic magnon that coherently precesses in time. These results demonstrate the emergence of a transient metallic state that preserves long-range antiferromagnetism, a phase that cannot be reached by simply tuning the temperature. More broadly, our findings open an avenue toward the exciton-mediated optical manipulation of magnetism.

16.
J Neurochem ; 115(5): 1161-71, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21039520

RESUMO

Microglia are known to be a primary inflammatory cell type in the brain. However, microglial inflammatory responses are attenuated in the injured brain compared to those in cultured pure microglia. In the present study, we found that astrocytes challenged by oxygen-glucose deprivation (OGD) or H(2) O(2) released soluble factor(s) and attenuated microglial inflammatory responses. Conditioned medium prepared from astrocytes treated with OGD (OGD-ACM) or H(2) O(2) (H(2) O(2) -ACM) significantly reduced the levels of interferon-γ (IFN-γ)-induced microglial inflammatory mediators, including inducible nitric oxide synthase, at both the mRNA and protein levels. The anti-inflammatory effect of astrocytes appeared very rapidly (within 5min), but was not closely correlated with the extent of astrocyte damage. Both OGD-ACM and H(2) O(2) -ACM inhibited STAT nuclear signaling, as evidenced by a reduction in both STAT-1/3 binding to the IFN-γ-activated site and IFN-γ-activated site promoter activity. However, both phosphorylation and nuclear translocation of STAT-1/3 was unchanged in IFN-γ-treated microglia. The active component(s) in OGD-ACM were smaller than 3kDa, and displayed anti-inflammatory effects independent of protein synthesis. These results suggest that, in the injured brain, astrocytes may act as a controller to rapidly suppress microglial activation.


Assuntos
Anti-Inflamatórios/farmacologia , Astrócitos/fisiologia , Regulação da Expressão Gênica/fisiologia , Microglia/efeitos dos fármacos , Animais , Animais Recém-Nascidos , Astrócitos/química , Astrócitos/efeitos dos fármacos , Córtex Cerebral/citologia , Meios de Cultivo Condicionados/farmacologia , Ensaio de Desvio de Mobilidade Eletroforética/métodos , Regulação da Expressão Gênica/efeitos dos fármacos , Glucose/deficiência , Peróxido de Hidrogênio/farmacologia , Hipóxia/metabolismo , Interferon gama/farmacologia , Líquido Intracelular/efeitos dos fármacos , Líquido Intracelular/metabolismo , L-Lactato Desidrogenase/metabolismo , Óxido Nítrico Sintase Tipo II/metabolismo , Oligonucleotídeos/metabolismo , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismo , Fatores de Transcrição STAT/metabolismo , Transfecção/métodos
17.
Ophthalmology ; 117(11): 2112-9.e3, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20561686

RESUMO

PURPOSE: To examine the grading (interrater) reliability of the Age-Related Eye Disease Study (AREDS) Clinical Lens Grading System (ARLNS). DESIGN: Evaluation of diagnostic test or technology. PARTICIPANTS: One hundred fifty volunteers (284 eyes). METHODS: Participants with lens opacities of varying severity were independently graded at the slit lamp for cataract severity by 2 examiners (retinal or anterior segment specialists) using the ARLNS, which employs 3 standard photographs of increasing severity for classifying each of the 3 major types of opacity. Lens photographs were taken and graded at a reading center using the more detailed AREDS System for Classifying Cataracts from photographs. MAIN OUTCOME MEASURES: The Pearson correlation, weighted-kappa, and limits-of-agreement statistics were used to assess the interrater agreement of the gradings. RESULTS: Examinations were performed on 284 lenses (150 participants). Tests of interrater reliability between pairs of clinicians showed substantial agreement between clinicians for cortical and posterior subcapsular opacities and moderate agreement for nuclear opacities. A similar pattern and strength of agreement was present when comparing scores of retinal versus anterior segment specialists. Interrater agreement between clinical and reading center gradings was not as great as inter-clinician agreement. CONCLUSIONS: Interrater agreements were in the moderate to substantial range for the clinical assessment of lens opacities. Inherent differences in cataract classification systems that rely on slit lamp vs photographic assessments of lens opacities may explain some of the disagreement noted between slit lamp and photographic gradings. Given the interrater reliability statistics for clinicians and the simplicity of the grading procedure, ARLNS is presented for use in studies requiring a simple, inexpensive method for detecting the presence and severity of the major types of lens opacities. FINANCIAL DISCLOSURE(S): The authors have no proprietary or commercial interest in any of the materials discussed in this article.


Assuntos
Envelhecimento/fisiologia , Catarata/classificação , Técnicas de Diagnóstico Oftalmológico , Cristalino/patologia , Fotografação/classificação , Adulto , Idoso , Idoso de 80 Anos ou mais , Catarata/diagnóstico , Feminino , Humanos , Degeneração Macular/patologia , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Fotografação/instrumentação , Reprodutibilidade dos Testes , Acuidade Visual
18.
Retina ; 30(3): 459-67, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20038863

RESUMO

PURPOSE: Inflammation may play an important role in the pathogenesis of diabetic macular edema, a major cause of vision loss in persons with diabetes. The purpose of this study was to evaluate combined antiinflammatory therapy and laser approaches for treating patients with diabetic macular edema. METHODS: In this prospective, factorial, randomized, multicenter trial, we compared cyclo-oxygenase-2 inhibitor (celecoxib) with placebo and diode grid laser with standard Early Treatment Diabetic Retinopathy Study focal laser treatment in 86 participants with diabetic macular edema. The primary outcome is change in visual acuity of > or = 15 letters from baseline, and the secondary outcomes include a 50% reduction in the retinal thickening of diabetic macular edema measured by optical coherence tomography and a 50% reduction in leakage severity on fluorescein angiography. RESULTS: Visual acuity and retinal thickening data from >2 years of follow-up did not show evidence of differences between the medical and laser treatments. However, participants assigned to the celecoxib group were more likely to have a reduction in fluorescein leakage when compared with the placebo group (odds ratio = 3.6; P < 0.01). CONCLUSION: This short-term study did not find large visual function benefits of treatment with celecoxib or diode laser compared with those of standard laser treatment. A suggestive effect of celecoxib in reducing fluorescein leakage was observed.


Assuntos
Inibidores de Ciclo-Oxigenase 2/uso terapêutico , Retinopatia Diabética/terapia , Lasers de Estado Sólido/uso terapêutico , Edema Macular/terapia , Pirazóis/uso terapêutico , Sulfonamidas/uso terapêutico , Administração Oral , Permeabilidade Capilar , Celecoxib , Terapia Combinada , Inibidores de Ciclo-Oxigenase 2/administração & dosagem , Retinopatia Diabética/fisiopatologia , Feminino , Angiofluoresceinografia , Seguimentos , Humanos , Edema Macular/fisiopatologia , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Estudos Prospectivos , Pirazóis/administração & dosagem , Retina/patologia , Sulfonamidas/administração & dosagem , Tomografia de Coerência Óptica , Acuidade Visual/fisiologia
19.
Sci Rep ; 10(1): 20998, 2020 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-33268797

RESUMO

With the advanced investigations into low-dimensional systems, it has become essential to find materials having interesting lattices that can be exfoliated down to monolayer. One particular important structure is a kagome lattice with its potentially diverse and vibrant physics. We report a van-der-Waals kagome lattice material, Pd3P2S8, with several unique properties such as an intriguing flat band. The flat band is shown to arise from a possible compact-localized state of all five 4d orbitals of Pd. The diamagnetic susceptibility is precisely measured to support the calculated susceptibility obtained from the band structure. We further demonstrate that Pd3P2S8 can be exfoliated down to monolayer, which ultimately will allow the possible control of the localized states in this two-dimensional kagome lattice using the electric field gating.

20.
Circulation ; 117(16): 2104-13, 2008 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-18378608

RESUMO

BACKGROUND: Observational studies and randomized trials have reported increased cardiovascular risk associated with cyclooxygenase-2 inhibitors. Prior placebo-controlled randomized studies had limited ability to assess the relationship of either celecoxib dose or pretreatment cardiovascular status to risk associated with celecoxib. Our aim was to assess the cardiovascular risk associated with celecoxib in 3 dose regimens and to assess the relationship between baseline cardiovascular risk and effect of celecoxib on cardiovascular events. METHODS AND RESULTS: We performed a patient-level pooled analysis of adjudicated data from 7950 patients in 6 placebo-controlled trials comparing celecoxib with placebo for conditions other than arthritis with a planned follow-up of at least 3 years. Patients were administered celecoxib in 3 dose regimens: 400 mg QD, 200 mg BID, or 400 mg BID. From the pooled data, we calculated a hazard ratio for all dose regimens combined and individual hazard ratios for each dose regimen and examined whether celecoxib-related risk was associated with baseline cardiovascular risk. The primary end point was the combination of cardiovascular death, myocardial infarction, stroke, heart failure, or thromboembolic event. With 16,070 patient-years of follow-up, the hazard ratio for the composite end point combining the tested doses was 1.6 (95% CI, 1.1 to 2.3). The risk, which increased with dose regimen (P=0.0005), was lowest for the 400-mg-QD dose (hazard ratio, 1.1; 95% CI, 0.6 to 2.0), intermediate for the 200-mg-BID dose (hazard ratio, 1.8; 95% CI, 1.1 to 3.1), and highest for the 400-mg-BID dose (hazard ratio, 3.1; 95% CI, 1.5 to 6.1). Patients at highest baseline risk demonstrated disproportionately greater risk of celecoxib-related adverse events (P for interaction=0.034). CONCLUSIONS: We observed evidence of differential cardiovascular risk as a function of celecoxib dose regimen and baseline cardiovascular risk. By further clarifying the extent of celecoxib-related cardiovascular risk, these findings may help guide treatment decisions for patients who derive clinical benefit from selective cyclooxygenase-2 inhibition.


Assuntos
Doenças Cardiovasculares/epidemiologia , Inibidores de Ciclo-Oxigenase 2/efeitos adversos , Pirazóis/efeitos adversos , Ensaios Clínicos Controlados Aleatórios como Assunto/estatística & dados numéricos , Sulfonamidas/efeitos adversos , Celecoxib , Seguimentos , Humanos , Medição de Risco , Fatores de Risco
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