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1.
Phys Rev Lett ; 131(20): 201802, 2023 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-38039466

RESUMO

We search for energetic electron recoil signals induced by boosted dark matter (BDM) from the galactic center using the COSINE-100 array of NaI(Tl) crystal detectors at the Yangyang Underground Laboratory. The signal would be an excess of events with energies above 4 MeV over the well-understood background. Because no excess of events are observed in a 97.7 kg·yr exposure, we set limits on BDM interactions under a variety of hypotheses. Notably, we explored the dark photon parameter space, leading to competitive limits compared to direct dark photon search experiments, particularly for dark photon masses below 4 MeV and considering the invisible decay mode. Furthermore, by comparing our results with a previous BDM search conducted by the Super-Kamionkande experiment, we found that the COSINE-100 detector has advantages in searching for low-mass dark matter. This analysis demonstrates the potential of the COSINE-100 detector to search for MeV electron recoil signals produced by the dark sector particle interactions.

2.
Clin Radiol ; 76(1): 80.e15-80.e23, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32950255

RESUMO

AIM: To evaluate the clinical significance of hyperattenuating lesions on CT after mechanical thrombectomy for acute ischaemic stroke, and to identify imaging factors that predict symptomatic haemorrhage and unfavourable outcomes. MATERIALS AND METHODS: Seventy-eight patients with acute ischaemic stroke in the anterior circulation who underwent mechanical thrombectomy were evaluated. All patients underwent post-interventional unenhanced computed tomography (CT) within 24 h and follow-up CT or magnetic resonance imaging (MRI) within 7 days. Baseline characteristics and clinical outcomes were compared between patients with and without hyperattenuating lesions. In patients with hyperattenuating lesions, clinical and imaging factors that predict symptomatic haemorrhage and unfavourable outcomes were determined. RESULTS: Fifty-six of 78 patients (71.8%) demonstrated hyperattenuating lesions on post-interventional CT. Patients with hyperattenuating lesions showed lower Alberta Stroke Program Early CT score (ASPECTS), persistent/symptomatic haemorrhage, and unfavourable outcomes than those without. In patients with hyperattenuating lesions, larger hyperattenuating lesion volume (>21.3 ml; OR, 55.60, p<0.001) and perilesional oedema (OR, 46.04, p=0.015) were independent factors predicting symptomatic haemorrhage. Older age (OR, 1.2, p=0.006) and lower ASPECTS (OR, 0.45, p=0.046) were independent factors predicting unfavourable outcomes in patients with hyperattenuating lesions. Adding the volume of the hyperattenuating lesion to age and ASPECTS increased the predictive performance of unfavourable outcomes (area under the curve 0.874 versus 0.934, p=0.043). CONCLUSIONS: Hyperattenuating lesions on post-interventional CT are associated with increased risk of symptomatic haemorrhage and unfavourable outcomes. Larger hyperattenuating lesion volume is an independent factor of symptomatic haemorrhage and it has added predictive value for unfavourable outcomes.


Assuntos
Hemorragias Intracranianas/diagnóstico por imagem , AVC Isquêmico/diagnóstico por imagem , AVC Isquêmico/cirurgia , Trombectomia/métodos , Idoso , Meios de Contraste , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Interpretação de Imagem Radiográfica Assistida por Computador , Estudos Retrospectivos , Tomografia Computadorizada por Raios X
3.
Mol Biol (Mosk) ; 55(4): 617-625, 2021.
Artigo em Russo | MEDLINE | ID: mdl-34432779

RESUMO

MUC4 is a predominant membrane-tethered mucin lubricating and protecting the epithelial surface and playing various biological roles in the renewal and differentiation of epithelial cells, cell signaling, cell adhesion, and carcinogenesis. Interestingly, recent studies have demonstrated that MUC4 expression regulates the epithelial-mesenchymal transition (EMT) of cancer cells in ovarian, pancreatic, and lung cancer. However, the effects of MUC4 expression on EMT in human airway epithelial cells are not yet well known. Here, we describe the effects of transforming growth factor beta 1 (TGF-ß1)-induced MUC4 expression on EMT and evaluate its downstream signaling pathway in human airway epithelial cells. In human airway epithelial NCI-H292 cells, exposure to TGF-ß1 induced expression of MUC4, CDH2, VIM and SNAI1 genes and encoded by them proteins, MUC4, N-cadherin, vimentin and Snail, and reduced the level of CDH1 and its product, E-cadherin. In MUC4-knockdown cells, TGF-ß1-induced expression levels of MUC4, CDH2, VIM and SNAI1 and corresponding proteins were suppressed, but CDH1 and E-cadherin levels were not. In addition, TGF-ß1-induced phosphorylation of extracellular signal regulated kinase 1/2 (ERK1/2) was suppressed, but that of Smad2/3, Akt, and p38 was not. The results of this study suggest that MUC4 silencing inhibits TGF-ß1 -induced EMT via the ERK1/2 pathway, and a possible role of MUC4 in the induction of EMT in human airway epithelial cells.


Assuntos
Transição Epitelial-Mesenquimal , Fator de Crescimento Transformador beta1 , Células Epiteliais/metabolismo , Transição Epitelial-Mesenquimal/genética , Humanos , Sistema de Sinalização das MAP Quinases , Proteína Quinase 3 Ativada por Mitógeno/genética , Mucina-4/genética , Mucina-4/metabolismo , Fator de Crescimento Transformador beta1/genética
4.
Eur J Neurol ; 27(8): 1672-1679, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32392368

RESUMO

BACKGROUND AND PURPOSE: The objective of this study was to investigate the association between body mass index (BMI) and both initial stroke severity at presentation and functional outcomes after acute ischaemic stroke (AIS) in patients with non-valvular atrial fibrillation (NVAF). METHODS: Patients were categorized on the basis of their BMI into underweight (BMI <18.5, n = 111), normal (18.5 ≤ BMI <25, n = 1036) and overweight to obese (BMI ≥25, n = 472) groups. Initial stroke severity was assessed using the National Institutes of Health Stroke Scale (NIHSS) score and functional outcomes were assessed using the modified Rankin Scale score at discharge. The differences in stroke severity and functional outcomes were compared between groups using robust log-linear regression with a Poisson distribution and binary logistic regression analysis. RESULTS: A total of 1619 AIS patients with NVAF from six hospitals were included. Compared with the NIHSS scores [median 5, interquartile range (IQR) 2-14] of normal-weight patients, the NIHSS scores (median 9, IQR 4-19) of underweight patients were more likely to be higher, whereas those of overweight to obese patients were lower (median 4, IQR 1-12) (P < 0.001). In terms of functional outcomes after stroke, underweight patients had a higher risk of poor functional outcomes (odds ratio 1.78, 95% confidence interval 1.09-2.56, P = 0.01) but overweight to obese patients had no significant difference in functional outcomes compared with normal-weight patients. CONCLUSION: An inverse association was found between BMI and stroke severity in AIS patients with NVAF. This suggests the presence of an obesity paradox for short-term outcomes in patients with NVAF.


Assuntos
Fibrilação Atrial , Isquemia Encefálica , AVC Isquêmico , Fibrilação Atrial/complicações , Fibrilação Atrial/epidemiologia , Índice de Massa Corporal , Isquemia Encefálica/complicações , Isquemia Encefálica/epidemiologia , Humanos , Fatores de Risco
5.
Rhinology ; 58(1): 66-73, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31680128

RESUMO

BACKGROUND: Airway inflammation and excessive mucin production are pathophysiological characteristics of airway diseases. Fipronil, a pesticide, is being extensively used in agriculture and veterinary medicine worldwide. However, this compound impairs immune function in non-target organisms. The present study aimed to evaluate the effect of fipronil on pro-inflammatory cytokine and mucus production and signalling pathways in human primary nasal METHODOLOGY: The effect of fipronil on pro-inflammatory cytokine and MUC5AC expression and the signalling pathway of fipronil were investigated using real-time PCR, enzyme immunoassays, immunofluorescence, and immunoblot analysis with specific inhibitors and small interfering RNA. RESULTS: Fipronil treatment increased pro-inflammatory cytokine interleukin (IL)-1beta, IL-6, IL-8, and MUC5AC expression in human primary nasal epithelial cells. It also induced phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) mitogenactivated protein kinase (MAPK), p38 MAPK, and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB). MAPK and NF-kB inhibitor treatment significantly inhibited increases in IL-1beta, IL-6, IL-8, and MUC5AC expression. Ex vivo data confirmed that fipronil-induced MUC5AC expression occurs through ERK1/2, p38, and NF-kB signalling pathways in nasal inferior turbinate tissue. CONCLUSIONS: Fipronil induced pro-inflammatory cytokine IL-1beta, IL-6, IL-8, and MUC5AC expression via ERK1/2 MAPK, p38 MAPK, and NF-kB in human primary nasal epithelial cells.


Assuntos
Citocinas/metabolismo , Células Epiteliais/efeitos dos fármacos , Mucina-5AC/metabolismo , Pirazóis/farmacologia , Células Cultivadas , Células Epiteliais/metabolismo , Humanos , NF-kappa B/metabolismo , Transdução de Sinais , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
6.
Phys Rev Lett ; 123(3): 031302, 2019 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-31386435

RESUMO

We present new constraints on the dark matter-induced annual modulation signal using 1.7 years of COSINE-100 data with a total exposure of 97.7 kg yr. The COSINE-100 experiment, consisting of 106 kg of NaI(Tl) target material, is designed to carry out a model-independent test of DAMA/LIBRA's claim of WIMP discovery by searching for the same annual modulation signal using the same NaI(Tl) target. The crystal data show a 2.7 cpd/kg/keV background rate on average in the 2-6 keV energy region of interest. Using a χ-squared minimization method we observe best fit values for modulation amplitude and phase of 0.0092±0.0067 cpd/kg/keV and 127.2±45.9 d, respectively.

7.
Phys Rev Lett ; 122(13): 131802, 2019 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-31012610

RESUMO

A search for inelastic boosted dark matter (IBDM) using the COSINE-100 detector with 59.5 days of data is presented. This relativistic dark matter is theorized to interact with the target material through inelastic scattering with electrons, creating a heavier state that subsequently produces standard model particles, such as an electron-positron pair. In this study, we search for this electron-positron pair in coincidence with the initially scattered electron as a signature for an IBDM interaction. No excess over the predicted background event rate is observed. Therefore, we present limits on IBDM interactions under various hypotheses, one of which allows us to explore an area of the dark photon parameter space that has not yet been covered by other experiments. This is the first experimental search for IBDM using a terrestrial detector.

8.
Phys Rev Lett ; 118(12): 121802, 2017 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-28388195

RESUMO

An experiment to search for light sterile neutrinos is conducted at a reactor with a thermal power of 2.8 GW located at the Hanbit nuclear power complex. The search is done with a detector consisting of a ton of Gd-loaded liquid scintillator in a tendon gallery approximately 24 m from the reactor core. The measured antineutrino event rate is 1976 per day with a signal to background ratio of about 22. The shape of the antineutrino energy spectrum obtained from the eight-month data-taking period is compared with a hypothesis of oscillations due to active-sterile antineutrino mixing. No strong evidence of 3+1 neutrino oscillation is found. An excess around the 5 MeV prompt energy range is observed as seen in existing longer-baseline experiments. The mixing parameter sin^{2}2θ_{14} is limited up to less than 0.1 for Δm_{41}^{2} ranging from 0.2 to 2.3 eV^{2} with a 90% confidence level.

9.
Dis Esophagus ; 30(8): 1-6, 2017 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-28575248

RESUMO

Catheter probe endoscopic ultrasonography (C-EUS) by ultrasonographic jelly-filled method has been used to evaluate esophageal subepithelial tumors (SETs). Ultrasonographic jelly is safe on the skin, but its internal safety has not been demonstrated. The jelly stored at room temperature is easily injected into the esophagus through the instrument channel of the endoscope. However, using jelly stored at room temperature remains problematic because the jelly is drained rapidly. We used cold lubricating jelly and an intravenous extension tube to resolve these problems. In this study, we evaluated the safety and efficacy of cold lubricating jelly-filled method. The medical records of patients who underwent C-EUS by using water or cold lubricating jelly-filled method for esophageal SETs from March 2013 to September 2016 in Gangneung Asan hospital were reviewed. Clinical characteristics and EUS findings were evaluated retrospectively. Image quality and procedure time between water and cold lubricating jelly-filled method were compared retrospectively. This study included 138 patients (74 males, 64 females) with esophageal SET with a mean age of 57.1 ± 11.1 years. Thirty-four patients had lesions in the upper esophagus, 58 patients had lesions in the middle esophagus, and 46 patients had lesions in the lower esophagus. The EUS diagnoses were leiomyoma (82.6%), hemangioma (4.3%), extrinsic compressive lesion (3.6%), granulosa cell tumor (2.9%), ectopic calcification (1.4%), cyst (1.4%), lipoma (0.7%), varix (0.7%), and inconclusive lesion (2.2%). The mean image score in the cold lubricating jelly filled-method group was higher than that in the water-filled method group (3.2 ± 0.7 vs. 2.8 ± 0.7, P = 0.002). The procedure time in the cold lubricating jelly filled-method group was shorter than that in the water-filled method group (10 minutes 27 seconds ± 4 minutes 22 seconds versus 13 minutes 20 seconds ± 6 minutes 20 seconds, P = 0.045). No procedure-related complication was observed. C-EUS using the cold lubricating jelly-filled method seems to provide better image quality and shorter procedure time compared with C-EUS using the water-filled method.


Assuntos
Catéteres , Endossonografia/instrumentação , Neoplasias Esofágicas/diagnóstico por imagem , Lubrificantes/uso terapêutico , Idoso , Temperatura Baixa , Endossonografia/métodos , Mucosa Esofágica/diagnóstico por imagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Tempo
10.
Clin Otolaryngol ; 42(3): 550-556, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27727517

RESUMO

OBJECTIVE: To determine the factors associated with rhinostomy shape after endoscopic dacryocystorhinostomy (DCR) in patients with primary acquired nasolacrimal duct obstruction. DESIGN: Retrospective comparative study. SETTING: University hospital. PARTICIPANTS: One hundred and two cases in 70 patients were included in the study. MAIN OUTCOME MEASURE: All cases were classified into three groups according to the healed appearance of the rhinostomy: flat, ladle and ice scoop type. The flat shape was characterised by an opening with a flat surrounding and no clear border between the lacrimal sac and the nasal mucosa. The ladle shape had a depressed base without markings of a lacrimal sac. The ice scoop shape had a depressed base with a clear border between the lacrimal sac and the nasal mucosa. Anatomic success was defined as patency with syringing and endoscopic evidence of ostial patency. Functional success was defined as visualisation of fluorescein dye at the ostium and relief from epiphora. Clinical information and intra- and postoperative endoscopic video findings were compared between the three groups. RESULTS: Of the 102 cases, 19 flat, 37 ladle and 46 ice scoop type rhinostomies were observed during the follow-up examinations. Among the variables studied, patient demographics and rhinostomy size and location did not differ between the three groups. However, intraoperative lacrimal sac findings (sac size, wall thickness and mobility), postoperative ostial shrinkage and rhinostomy movement were associated with postoperative rhinostomy shape (all P < 0.05). With regard to surgical outcomes, there were no differences in anatomical patency between the three groups. However, the flat group had a worse functional success rate (73.7%) than the ladle (91.9%) and ice scoop (97.8%) groups (P = 0.008). A higher degree of ostial shrinkage and poor rhinostomy movement was observed with the flat shape appearance, which had a small, thick and poorly mobile lacrimal sac. CONCLUSIONS: Lacrimal sac characteristics play a prominent role in determining rhinostomy shape after endoscopic DCR. The rhinostomy shape, along with the degree of ostial shrinkage and rhinostomy movement, is predictive of functional success after endoscopic DCR.


Assuntos
Dacriocistorinostomia/métodos , Obstrução dos Ductos Lacrimais/diagnóstico , Ducto Nasolacrimal/cirurgia , Cirurgia Endoscópica por Orifício Natural/métodos , Adulto , Idoso , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Cavidade Nasal , Ducto Nasolacrimal/diagnóstico por imagem , Período Pós-Operatório , Estudos Retrospectivos , Resultado do Tratamento
11.
Phys Rev Lett ; 116(21): 211801, 2016 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-27284648

RESUMO

The RENO experiment has analyzed about 500 live days of data to observe an energy dependent disappearance of reactor ν[over ¯]_{e} by comparing their prompt signal spectra measured in two identical near and far detectors. In the period between August of 2011 and January of 2013, the far (near) detector observed 31 541 (290 775) electron antineutrino candidate events with a background fraction of 4.9% (2.8%). The measured prompt spectra show an excess of reactor ν[over ¯]_{e} around 5 MeV relative to the prediction from a most commonly used model. A clear energy and baseline dependent disappearance of reactor ν[over ¯]_{e} is observed in the deficit of the observed number of ν[over ¯]_{e}. Based on the measured far-to-near ratio of prompt spectra, we obtain sin^{2}2θ_{13}=0.082±0.009(stat)±0.006(syst) and |Δm_{ee}^{2}|=[2.62_{-0.23}^{+0.21}(stat)_{-0.13}^{+0.12}(syst)]×10^{-3} eV^{2}.

13.
Phys Rev Lett ; 113(12): 121301, 2014 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-25279618

RESUMO

Bosonic superweakly interacting massive particles (super-WIMPs) are a candidate for warm dark matter. With the absorption of such a boson by a xenon atom, these dark matter candidates would deposit an energy equivalent to their rest mass in the detector. This is the first direct detection experiment exploring the vector super-WIMPs in the mass range between 40 and 120 keV. With the use of 165.9 day of data, no significant excess above background was observed in the fiducial mass of 41 kg. The present limit for the vector super-WIMPs excludes the possibility that such particles constitute all of dark matter. The absence of a signal also provides the most stringent direct constraint on the coupling constant of pseudoscalar super-WIMPs to electrons. The unprecedented sensitivity was achieved exploiting the low background at a level 10(-4) kg-1 keVee-1 day-1 in the detector.

14.
Eur J Neurol ; 21(5): 779-84, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24612359

RESUMO

BACKGROUND AND PURPOSE: Although the stent retriever (SR) has shown a better reperfusion rate and clinical outcome than the older generation mechanical clot retrieval device, it is uncertain whether the SR is superior to intra-arterial fibrinolysis (IAF). METHODS: Ischaemic stroke patients who were treated with SR or IAF as initial endovascular treatment modality for unilateral arterial occlusion in the anterior circulation were included. Successful reperfusion was defined as Thrombolysis in Cerebral Infarction grade ≥2b. A favourable clinical outcome was defined as a modified Rankin Score ≤2 at 3 months. RESULTS: Between January 2009 and May 2012, 55 patients were treated with SR and 50 patients were treated with IAF. The baseline characteristics were similar between the two groups except for the occlusion site and rescue treatment. In binary logistic regression analysis adjusted for the occlusion site and rescue treatment, SR was independently associated with increased successful reperfusion [82.0% vs. 47.3%; odds ratio (OR) 5.21; 95% confidence interval (CI) 1.92-14.14) and a more favourable clinical outcome at 3 months (54.0% vs. 43.6%; OR 3.40; 95% CI 1.31-8.84). The frequency of symptomatic intracranial haemorrhage and mortality at 3 months was not different between the two groups. CONCLUSIONS: Stent retriever was as safe as and more effective than IAF. Our findings suggest that SR may be considered as an initial modality rather than IAF in acute stroke patients who undergo endovascular treatment.


Assuntos
Stents , Acidente Vascular Cerebral/terapia , Terapia Trombolítica/métodos , Idoso , Idoso de 80 Anos ou mais , Isquemia Encefálica/complicações , Feminino , Fibrinólise , Humanos , Masculino , Pessoa de Meia-Idade , Reperfusão , Estudos Retrospectivos , Estatísticas não Paramétricas , Acidente Vascular Cerebral/etiologia , Trombectomia/métodos , Tomógrafos Computadorizados , Resultado do Tratamento
15.
Eur J Neurol ; 21(3): 463-9, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24330330

RESUMO

BACKGROUND AND PURPOSE: Increased arterial stiffness causes vessel damage in the end-organs. Therefore small vessels in the brain may be susceptible to increased arterial stiffness. Cerebral microbleeds (CMBs) are topographically or pathophysiologically categorized as deep or infratentorial type and strictly lobar type. Whether the presence and location of CMBs are associated with brachial-ankle pulse wave velocity (baPWV) which represents a measure of arterial stiffness was investigated. METHODS: Between June 2006 and January 2012, 1137 consecutive patients diagnosed with non-cardioembolic acute ischaemic stroke and who underwent baPWV measurement and brain gradient-echo imaging were enrolled. CMBs were classified as deep or infratentorial or strictly lobar according to their location. Severity of leukoaraiosis was determined using the Fazekas scoring system. RESULTS: CMBs were found in 30.7% of the included patients. These patients were older than those without CMBs. Mean baPWV was higher in patients with CMBs than in those without (20 ± 5 m/s vs. 19 ± 5 m/s; P = 0.001). When comparing baPWV according to the location of the CMB, it was higher in the deep or infratentorial CMB group than in the strictly lobar CMB group (22 ± 5 m/s vs. 20 ± 5 m/s; P = 0.001). In univariate and multivariate multinomial logistic regression analyses, baPWV was found to be independently associated with deep or infratentorial CMBs. CONCLUSIONS: Arterial stiffness was independently associated with deep or infratentorial CMBs but not lobar CMBs. These findings suggest a pathophysiological association between arterial stiffness and CMBs in the deep or infratentorial region.


Assuntos
Encéfalo/patologia , Hemorragia Cerebral/etiologia , Arteriosclerose Intracraniana/etiologia , Acidente Vascular Cerebral/complicações , Rigidez Vascular/fisiologia , Idoso , Idoso de 80 Anos ou mais , Análise de Variância , Hemorragia Cerebral/diagnóstico por imagem , Feminino , Humanos , Arteriosclerose Intracraniana/diagnóstico , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Fatores de Risco , Acidente Vascular Cerebral/diagnóstico por imagem , Ultrassonografia Doppler Transcraniana
16.
Phys Chem Chem Phys ; 16(14): 6735-42, 2014 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-24590068

RESUMO

Recent research in heterogeneous catalysis, especially on size-selected model systems under UHV conditions and also in realistic catalytic environments, has proved that it is necessary to think in terms of the exact number of atoms when it comes to catalyst design. This is of utmost importance if the amount of noble metal, gold in particular, is to be reduced for practical reactions like CO oxidation. Here it is shown that on TiO2 only Au6 and Au7 clusters are active for CO oxidation which holds for the single crystal, thin films, and titania clusters deposited on HOPG. Size-selected cluster deposition and TPD methods have been employed to investigate the CO oxidation activity of Aun/TiO2 systems which are compared to recent results reported by Lee et al. to form a consistent picture in which only two species can be regarded as "active". The efficiency of investigated Aun/(TiO2)93/HOPG composite materials is attributed to carbon-assisted oxygen spillover from gold to support particles and across grain boundaries.

17.
Nano Lett ; 13(5): 1962-8, 2013 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-23586702

RESUMO

A fundamental understanding of chemical sensing mechanisms in graphene-based chemical field-effect transistors (chemFETs) is essential for the development of next generation chemical sensors. Here we explore the hidden sensing modalities responsible for tailoring the gas detection ability of pristine graphene sensors by exposing graphene chemFETs to electron donor and acceptor trace gas vapors. We uncover that the sensitivity (in terms of modulation in electrical conductivity) of pristine graphene chemFETs is not necessarily intrinsic to graphene, but rather it is facilitated by external defects in the insulating substrate, which can modulate the electronic properties of graphene. We disclose a mixing effect caused by partial overlap of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of adsorbed gas molecules to explain graphene's ability to detect adsorbed molecules. Our results open a new design space, suggesting that control of external defects in supporting substrates can lead to tunable graphene chemical sensors, which could be developed without compromising the intrinsic electrical and structural properties of graphene.

18.
Diabetologia ; 56(2): 412-22, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23150180

RESUMO

AIMS/HYPOTHESIS: Fenofibrate is a drug used to treat hyperlipidaemia that works by inhibiting hepatic triacylglycerol synthesis. Sterol regulatory element binding protein-1c (SREBP-1c) is a major regulator of the expression of genes involved in hepatic triacylglycerol synthesis. In addition, endoplasmic reticulum (ER)-bound transcription factor families are involved in the control of various metabolic pathways. Here, we show a novel function for an ER-bound transcription factor, cAMP response element binding protein H (CREBH), in fenofibrate-mediated inhibition of hepatic lipogenesis. METHODS: The effects of fenofibrate and adenovirus-mediated Crebh (also known as Creb313) overexpression (Ad-Crebh) on hepatic SREBP-1c production and lipogenesis in vitro and in vivo were investigated. We also examined whether downregulation of endogenous hepatic Crebh by small interfering (si)RNA restores the fenofibrate effect on hepatic lipogenesis and SREBP-1c production. Finally, we examined the mechanism by which CREBH inhibits hepatic SREBP-1c production. RESULTS: Fasting and fenofibrate treatment induced CREBH production and decreased SREBP-1c levels. Indeed, Ad-Crebh inhibited insulin- and liver X receptor agonist TO901317-induced Srebp-1c (also known as Srebf1) mRNA expression in cultured hepatocytes. Moreover, increased production of CREBH in the liver of mice following tail-vein injection of Ad-Crebh inhibited high-fat diet-induced hepatic steatosis through inhibition of Srebp-1c expression. The inhibition of endogenous Crebh expression by siRNA restored fenofibrate-induced suppression of Srebp-1c expression and hepatic lipid accumulation both in vitro and in vivo. CONCLUSIONS/INTERPRETATION: These results show that fenofibrate decreases hepatic lipid synthesis through induction of CREBH. This study suggests CREBH as a novel negative regulator of SREBP-1c production and hepatic lipogenesis.


Assuntos
Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Fenofibrato/farmacologia , Lipogênese/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Animais , Linhagem Celular , Linhagem Celular Tumoral , Fígado Gorduroso/metabolismo , Células Hep G2 , Humanos , Camundongos , Ratos , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo
19.
Eur J Neurol ; 20(9): 1256-63, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23560528

RESUMO

BACKGROUND AND PURPOSE: CHADS2 and CHA2 DS2 -VASc scores are measurement tools that stratify thromboembolic risk in patients with non-valvular atrial fibrillation, and are predictive of cerebral atherosclerosis, fatal stroke and ischaemic heart disease. Patients with higher CHADS2 and CHA2 DS2 -VASc scores are more likely to have had an akinetic/hypokinetic left ventricular segment or a recent myocardial infarction, all of which are associated with coronary artery disease (CAD). Most of the CHADS2 score components are also risk factors for atherosclerosis. Thus, CHADS2 and CHA2 DS2 -VASc scores may be predictive of CAD. METHODS: In all, 1733 consecutive patients with acute ischaemic stroke who underwent multi-slice computed tomography coronary angiography were enrolled. The association of CHADS2 and CHA2 DS2 -VASc scores with the presence and severity of CAD was investigated. RESULTS: Of the 1733 patients, 1220 patients (70.4%) had any degree of CAD and 576 (33.3%) had significant CAD (≥ 50% stenosis in at least one coronary artery). As the CHADS2 and CHA2 DS2 -VASc scores increased, the presence of CAD also increased (P < 0.001). The severity of CAD was correlated with CHADS2 score (Spearman coefficient 0.229, P < 0.001) and CHA2 DS2 -VASc score (Spearman coefficient 0.261, P < 0.001). In multivariate analysis, after adjusting for confounding factors, CHADS2 and CHA2 DS2 -VASc scores ≥2 were independently associated with CAD. The CHA2 DS2 -VASc score was a better predictor of the presence of CAD than the CHADS2 score on area under the curve analysis. CONCLUSION: CHADS2 and CHA2 DS2 -VASc scores were predictive of the presence and severity of CAD in patients with stroke. When a patient has high CHADS2 or CHA2 DS2 -VASc scores, physicians should consider coronary artery evaluation.


Assuntos
Doença da Artéria Coronariana/complicações , Valor Preditivo dos Testes , Medição de Risco/métodos , Acidente Vascular Cerebral/complicações , Idoso , Angiografia Coronária , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco
20.
Eur J Neurol ; 20(3): 502-508, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23057579

RESUMO

BACKGROUND AND PURPOSE: Cerebral microbleeds (CMBs) are extravasations of blood from lipohyalinized or amyloid angiopathic cerebral arterioles, and the presence and numbers of CMBs are significantly associated with the development of oral anticoagulation (OA)-related intracranial haemorrhage (ICH). The aim of this study was to investigate whether there is a difference in CMBs burden according to CHADS(2) scores or CHA(2) DS(2) -VASc scores in non-valvular atrial fibrillation (NVAF) patients. METHODS: We included 550 ischaemic stroke patients who had NVAF and who had undergone brain magnetic resonance imaging (MRI) with gradient-recalled echo (GRE) T2 sequences from our prospective stroke registry between January 2005 and November 2011. We calculated CHADS(2) scores and CHA(2) DS(2) -VASc scores for all patients based on their underlying cardiovascular diseases. The presence, location and number of CMBs were assessed in each patient. We also investigated whether the CMBs were actually associated with the development of ICH during follow-up. RESULTS: The mean patient age was 70.4 ± 10.5 years, and 324 (58.9%) patients were men. One-hundred and seventy-three patients (31.5%) had CMBs detected on GRE MRI. Higher CHADS(2) scores or CHA(2) DS(2) -VASc scores were strongly associated with the presence and number of CMBs. During follow-up of median 3.1 ± 1.6 years, the presence of CMBs was independently associated with the development of ICH, whilst the CHADS(2) scores or CHA(2) DS(2) -VASc scores were not. CONCLUSIONS: Considering the positive association between the presence of CMBs and OA-related ICH, our results suggest that the increase in ICH in high-risk groups during OA may be related to an increased burden of CMBs.


Assuntos
Fibrilação Atrial/complicações , Encéfalo/patologia , Doenças Cardiovasculares/complicações , Acidente Vascular Cerebral/complicações , Idoso , Anticoagulantes/efeitos adversos , Fibrilação Atrial/tratamento farmacológico , Encéfalo/irrigação sanguínea , Feminino , Humanos , Hemorragias Intracranianas/complicações , Imageamento por Ressonância Magnética , Masculino , Medição de Risco/métodos , Acidente Vascular Cerebral/prevenção & controle
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