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1.
Nano Lett ; 22(21): 8475-8481, 2022 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-36282025

RESUMO

Artificial fabrication of a monolayer Kagome material can offer a promising opportunity to explore exceptional quantum states and phenomena in low dimensionality. Here, we have systematically studied a monatomic Ni Kagome lattice grown on Pb(111) by scanning tunneling microscopy/spectroscopy (STM/STS) and density functional theory (DFT). Sawtooth edge structures with distinct heights due to subsurface Ni atoms have been revealed, leading to asymmetric edge scattering of surface electrons on Pb(111). In addition, a local maximum at about -0.2 eV in tunneling spectra represents a manifestation of characteristic phase-destructive flat bands. Although charge transfer from underlying Pb(111) substrate results in a vanishing magnetic moment of Ni atoms, the proximity-induced superconducting gap is slightly enhanced on the Ni Kagome lattice. In light of single-atomic-layer Ni Kagome lattice on superconducting Pb(111) substrate, it could serve as an ideal platform to investigate the interplay between Kagome physics and superconductivity down to the two-dimensional limit.

2.
Artigo em Inglês | MEDLINE | ID: mdl-35575457

RESUMO

A proximity effect facilitates the penetration of Cooper pairs that permits superconductivity in a normal metal, offering a promising approach to turn heterogeneous materials into superconductors and develop exceptional quantum phenomena. Here, we have systematically investigated proximity-induced anisotropic superconductivity in a monolayer Ni-Pb binary alloy by combining scanning tunneling microscopy/spectroscopy (STM/STS) with theoretical calculations. By means of high-temperature growth, the (33×33)R30o Ni-Pb surface alloy has been fabricated on Pb(111) and the appearance of a domain boundary as well as a structural phase transition can be deduced from a half-unit-cell lattice displacement. Given the high spatial and energy resolution, tunneling conductance (dI/dU) spectra have resolved the reduced but anisotropic superconducting gap ΔNiPb ≈ 1.0 meV, in stark contrast to the isotropic ΔPb ≈ 1.3 meV. In addition, the higher density of states at the Fermi energy (D(EF)) of the Ni-Pb surface alloy results in an enhancement of coherence peak height. According to the same Tc ≈ 7.1 K with Pb(111) from the temperature-dependent ΔNiPb and the short decay length Ld ≈ 3.55 nm from the spatially monotonic decrease of ΔNiPb, both results are supportive of a proximity-induced superconductivity. Despite a lack of a bulk counterpart, the atomically thick Ni-Pb bimetallic compound opens a pathway to engineer superconducting properties down to the two-dimensional limit, giving rise to the emergence of anisotropic superconductivity via a proximity effect.

3.
Pharmacopsychiatry ; 52(3): 134-141, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29660754

RESUMO

INTRODUCTION: In recent decades, concern about safety of antidepressants has been raised but the risk between antidepressants and lung cancer has not yet been established. METHODS: A case-control study was conducted by using a nationwide database in Taiwan. The case groups were new onset lung cancer diagnosis during 1999-2008 and age- and gender-matched controls were selected among those without any cancer. The cumulative exposure dose before the lung cancer diagnosis was added and risks were calculated according to the levels of defined daily dose and classes of antidepressants. RESULTS: A total of 39,001 individuals with lung cancer and 189,906 individuals without lung cancer between 1999 and 2008 were included in the analysis. Antidepressants, of any class, were not associated with elevated risks for lung cancer with the exception of bupropion at high exposure levels (odds ratio=4.81, 95% confidence interval=1.39-16.71). DISCUSSION: Antidepressant prescription was not associated with elevation of lung cancer incidence using a nationally representative sample. The elevated risk for lung cancer with bupropion at high doses may be a bias by indication and warrant longitudinal investigation.


Assuntos
Antidepressivos de Segunda Geração/efeitos adversos , Bupropiona/efeitos adversos , Neoplasias Pulmonares/epidemiologia , Estudos de Casos e Controles , Feminino , Humanos , Estudos Longitudinais , Neoplasias Pulmonares/induzido quimicamente , Masculino , Programas Nacionais de Saúde/estatística & dados numéricos , Prescrições/estatística & dados numéricos , Estudos Retrospectivos , Fatores de Risco , Taiwan/epidemiologia
4.
Food Chem Toxicol ; 71: 149-58, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24932919

RESUMO

This study aimed to determine the contents of 16 PAHs in kindling-free-charcoal grilled meat and seafood products by GC-MS coupled with a QuEChERS method, and estimate the potential risk associated with consumption of those products in Taiwan. Results showed that the total PAHs contents ranged from 6.3±0.9 to 238.8±8.3 ng/g in poultry meat, 0.1±0.0-547.5±12.2 ng/g in red meat, and 6.6±1.4-249.7±6.4 ng/g in seafood products. Among various PAHs, the highly carcinogenic benzo[a]pyrene was detected in chicken breast grilled at 84°C (30 min), chicken heart at 100°C (26 min), chicken drumstick at 74°C (20 min), duck drumstick at 85°C (40 min), and lamb steak at 88°C (12 min), with its level amounting to 1.3±0.0, 2.4±0.1, 4.0±1.3, 3.1±0.0, and 5.8±0.5 ng/g, respectively. The generation of PAHs was associated with grilling time, temperature and fat content. Risk assessment of dietary exposure to PAHs revealed toxicity equivalent to range from ND - 6.174±0.505 µg/g and margin of exposure was >10,000, which agreed with the EFSA's definition of low public health concern. The lifelong average daily PAHs intake was higher for adults than for elderly people in Taiwan, however, consumption of kindling-free-charcoal grilled meat should not be a public health concern based on cancer risk potency.


Assuntos
Culinária , Produtos da Carne/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Gorduras na Dieta/análise , Cromatografia Gasosa-Espectrometria de Massas , Taiwan
5.
J Agric Food Chem ; 61(31): 7645-53, 2013 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-23855713

RESUMO

Polycyclic aromatic hydrocarbons (PAHs) represent an important pollutant in foods and/or the environment. This study aimed to determine the PAH contents in sugar-smoked meat by employing a quick, easy, cheap, effective, rugged, safe (QuEChERS) method combined with a GC-MS technique and assess the dietary exposure of PAHs in Taiwan. Results showed that the longer the sugar-smoking duration, the more the total PAH formation. By sugar-smoking for 6 min, the total PAH contents generated in red meat (33.9 ± 3.1-125.5 ± 9.2 ppb) were higher than in poultry meat (19.1 ± 2.0-28.2 ± 1.2 ppb) and seafood (9.1 ± 1.4-31.8 ± 1.8 ppb), with lamb steak containing the largest amount of total PAHs. Most importantly, the highly carcinogenic benzo[a]pyrene remained undetected in all of the sugar-smoked meat samples. In addition, the cancer risk due to dietary PAH exposure based on total intake of meat in Taiwan was <2 × 10(-7). This outcome demonstrates that sugar-smoking can be adopted to replace the traditional smoking process with wood as smoke source.


Assuntos
Carcinógenos/análise , Culinária/métodos , Contaminação de Alimentos/análise , Carne/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Animais , Bovinos , Galinhas , Patos , Peixes , Cromatografia Gasosa-Espectrometria de Massas , Alimentos Marinhos/análise , Ovinos , Suínos , Taiwan
6.
Brain Connect ; 2(4): 177-90, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22817652

RESUMO

The function of sleep in humans has been investigated using simultaneous electroencephalography (EEG) and functional magnetic resonance imaging recordings to provide accurate sleep scores with spatial precision. Recent studies have demonstrated that spontaneous brain oscillations and functional connectivity dissociate during nonrapid eye movement (NREM) sleep; this leads to spontaneous cognitive processes, such as memory consolidation and emotional modulation. However, variations in network connectivity across the sleep stages or between sleep/wake transitions require further elucidation. We observed changes in the connectivity of the sensorimotor and default-mode networks (DMN) mediated by midnight sleep among 18 healthy participants. The results indicated that (1) functional connectivity in both networks showed increasing dissociation as NREM sleep deepened, whereas hyperconnectivity occurred during rapid eye movement (REM) sleep; and (2) compared with connectivity before sleep, the DMN presented a comparable connectivity pattern immediately after awakening, whereas the connectivity of the sensorimotor network remained disrupted. These findings showed that connectivity patterns dissociate and reconnect coherently in both cortical networks during NREM and REM sleep, respectively. After the person awakened, the DMN connectivity was re-established before the sensorimotor reconnection. These dynamic sleep-related dissociations and reconnections between sleep/wake conditions might provide the key to understanding cognitive modulations in sleep. If so, connectivity changes might serve as an alternative indicator beyond the EEG signature to unveil the spontaneous processes that occur during sleep.


Assuntos
Encéfalo/fisiologia , Rede Nervosa/fisiologia , Vias Neurais/fisiologia , Fases do Sono/fisiologia , Vigília/fisiologia , Adolescente , Adulto , Eletroencefalografia , Humanos , Imageamento por Ressonância Magnética , Masculino , Fatores de Tempo , Adulto Jovem
7.
J Agric Food Chem ; 60(6): 1380-9, 2012 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-22233505

RESUMO

The objectives of this research were to develop a method for the determination of 16 polycyclic aromatic hydrocarbons (PAHs) in poultry meat by combining the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method with gas chromatography-mass spectrometry (GC-MS) and study their formation during marinating and frying. The recoveries of 16 PAHs ranged from 94.5 to 104% in blank samples and from 71.2 to 104% in poultry meat samples. The quantitation limits of 16 PAHs were from 0.02 to 1 ng/mL, with the intraday variability being from 2.4 to 6.6% [percent relative standard deviation (RSD%)] and interday variability being from 3.3 to 7.1% (RSD%). Most PAHs followed a time-dependent increase over a 24 h marinating period, with naphthalene being generated in the largest amount. Among the various poultry meat, chicken gizzard produced the highest level of total PAHs after 24 h of marinating. A similar tendency was observed for most PAHs during frying of poultry meat, but a high amount of total PAHs was shown in duck drumstick after 15 min of frying.


Assuntos
Culinária/métodos , Cromatografia Gasosa-Espectrometria de Massas/métodos , Carne/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Aves Domésticas , Animais , Contaminação de Alimentos/análise , Temperatura Alta
8.
Talanta ; 86: 349-55, 2011 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-22063550

RESUMO

Rhinacanthus nasutus (L.) Kurz, a traditional Chinese herb possessing antioxidant and anti-cancer activities, has been reported to contain functional components like carotenoids and chlorophylls. However, the variety and amount of chlorophylls remain uncertain. The objectives of this study were to develop a high performance liquid chromatography-photodiode array detection-atmospheric pressure chemical ionization-mass spectrometry (HPLC-DAD-APCI-MS) method for determination of chlorophylls and their derivatives in hot-air-dried and freeze-dried R. nasutus. An Agilent Eclipse XDB-C18 column and a gradient mobile phase composed of methanol/N,N-dimethylformamide (97:3, v/v), acetonitrile and acetone were employed to separate internal standard zinc-phthalocyanine plus 12 cholorophylls and their derivatives within 21 min, including chlorophyll a, chlorophyll a', hydroxychlorophyll a, 15-OH-lactone chlorophyll a, chlorophyll b, chlorophyll b', hydroxychlorophyll b, pheophytin a, pheophytin a', hydroxypheophytin a, hydroxypheophytin a' and pheophytin b in hot-air-dried R. nasutus with flow rate at 1 mL/min and detection at 660 nm. But, in freeze-dried R. nasutus, only 4 chlorophylls and their derivatives, including chlorophyll a, chlorophyll a', chlorophyll b and pheophytin a were detected. Zinc-phthalocyanine was found to be an appropriate internal standard to quantify all the chlorophyll compounds. After quantification by HPLC-DAD, both chlorophyll a and pheophytin a were the most abundant in hot-air-dried R. nasutus, while in freeze-dried R. nasutus, chlorophyll a and chlorophyll b dominated.


Assuntos
Clorofila/análise , Medicamentos de Ervas Chinesas/análise , Liofilização/métodos , Temperatura Alta , Espectrometria de Massas/métodos , Acanthaceae/química , Cromatografia Líquida de Alta Pressão/métodos
9.
Analyst ; 136(15): 3194-202, 2011 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-21698314

RESUMO

Rhinacanthus nasutus (L.) Kurz (Trade name: Bai he ling zhi), a traditional medicinal herb, has been reported to possess anticancer and antioxidant activities. However, the composition of the major functional compounds, carotenoids, remains uncertain. The objectives of this study were to develop a high performance liquid chromatography-mass spectrometry (HPLC-MS) method for carotenoid composition determination in R. nasutus and for carotenoid change by freeze-drying and hot-air-drying. A total of 24 carotenoids were separated within 54 min by using a YMC C(30) column and a gradient mobile phase of methanol-acetonitrile-water (82 : 14 : 4, v/v/v) (A) and methylene chloride (100%) (B): 100% A initially, maintained for 10 min, decreased to 95% A in 25 min, 84% A in 30 min, 75% A in 37 min, 68% A in 40 min, 65% A in 47 min, and 55% A in 50 min with flow rate at 1 mL min(-1) and detection wavelength at 450 nm. The various carotenoids were identified by comparing the retention time, absorption spectra, Q-ratio and mass spectra of unknown peaks with reference standards as well as photoisomerized standards. Quantitation was carried out using an internal standard ß-apo-8'-carotenal, with all-trans-lutein and its cis isomers being present in the largest amount (862 µg g(-1)) in freeze-dried R. nasutus, followed by all-trans-violaxanthin (494 µg g(-1)), all-trans-ß-carotene and its cis isomers (479 µg g(-1)), all-trans-neoxanthin and its cis isomers (251 µg g(-1)), all-trans-α-carotene and its cis isomers (85.2 µg g(-1)), luteoxanthin (14.3 µg g(-1)), all-trans-zeaxanthin (3.94 µg g(-1)), ß-carotene-5,6-epoxide (3.45 µg g(-1)) and all-trans-ß-cryptoxanthin (1.03 µg g(-1)). Comparatively, some more carotenoids including cis-violaxanthin, luteoxanthin, cis-neoxanthin, neochrome, 13- or 13'-cis-lutein, 9- or 9'-cis-lutein, ß-carotene-5,6-epoxide, 9- or 9'-cis-ß-carotene, 13- or 13'-cis-ß-carotene, 15- or 15'-cis-ß-carotene and 13- or 13'-cis-α-carotene were generated in R. nasutus during hot-air-drying.


Assuntos
Acanthaceae/química , Carotenoides/análise , Espectrometria de Massas/métodos , Extratos Vegetais/análise , Carotenoides/isolamento & purificação , Cromatografia Líquida de Alta Pressão/métodos , Dessecação , Liofilização , Temperatura Alta , Limite de Detecção , Extratos Vegetais/isolamento & purificação
10.
Hybridoma (Larchmt) ; 25(1): 20-6, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16475878

RESUMO

TREM-like transcript-1 (TLT-1) was initially characterized as the putative inhibitory receptor within the TREM locus on chromosome 6 and was suggested to play a critical role in modulating TREM-associated immunity. Recently, TLT-1 was found not to function as an inhibiting member of the TREM family; however, it may play a significant role in maintaining vascular hemostasis, coagulation, and inflammation at sites of injury through its location in platelets. In this study, we have successfully generated a monoclonal antibody that can be applied to assays, including enzyme-linked immunosorbent assay (ELISA), Western immunoblotting, immunofluorescence, and Fluorescence-Activated Cell Sorter (Becton-Dickinson) (FACS), for the study of TLT-1 functions in physiological and pathological conditions.


Assuntos
Anticorpos Monoclonais/biossíntese , Receptores Imunológicos/imunologia , Animais , Anticorpos Monoclonais/isolamento & purificação , Plaquetas/metabolismo , Fusão Celular , Células Cultivadas , Citometria de Fluxo/métodos , Humanos , Hibridomas/metabolismo , Imunoensaio/métodos , Camundongos , Especificidade de Órgãos , Receptores Imunológicos/genética , Receptores Imunológicos/metabolismo , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/imunologia
11.
Biochem Biophys Res Commun ; 314(4): 931-6, 2004 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-14751221

RESUMO

Early detection and identification of SARS-CoV-infected patients and actions to prevent transmission are absolutely critical to prevent another SARS outbreak. Antibodies that specifically recognize the SARS-CoV spike and nucleocapsid proteins may provide a rapid screening method to allow accurate identification and isolation of patients with the virus early in their infection. For this reason, we raised peptide-induced polyclonal antibodies against SARS-CoV spike protein and polyclonal antibodies against SARS-CoV nucleocapsid protein using 6x His nucleocapsid recombinant protein. Western blot analysis and immunofluorescent staining showed that these antibodies specifically recognized SARS-CoV.


Assuntos
Glicoproteínas de Membrana/imunologia , Proteínas do Nucleocapsídeo/imunologia , Proteínas do Envelope Viral/imunologia , Sequência de Aminoácidos , Western Blotting , Imunofluorescência , Humanos , Glicoproteínas de Membrana/química , Dados de Sequência Molecular , Proteínas do Nucleocapsídeo/química , Glicoproteína da Espícula de Coronavírus , Frações Subcelulares , Proteínas do Envelope Viral/química
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