Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 464
Filtrar
5.
Sci Rep ; 9(1): 17032, 2019 Nov 19.
Artículo en Inglés | MEDLINE | ID: mdl-31745127

RESUMEN

Two-dimensional MoS2 has emerged as promising material for nanoelectronics and spintronics due to its exotic properties. However, high contact resistance at metal semiconductor MoS2 interface still remains an open issue. Here, we report electronic properties of field effect transistor devices using monolayer MoS2 channels and permalloy (Py) as ferromagnetic (FM) metal contacts. Monolayer MoS2 channels were directly grown on SiO2/Si substrate via chemical vapor deposition technique. The increase in current with back gate voltage (Vg) shows the tunability of FET characteristics. The Schottky barrier height (SBH) estimated for Py/MoS2 contacts is found to be +28.8 meV (at Vg = 0V), which is the smallest value reported so-far for any direct metal (magnetic or non-magnetic)/monolayer MoS2 contact. With the application of positive gate voltage, SBH shows a reduction, which reveals ohmic behavior of Py/MoS2 contacts. Low SBH with controlled ohmic nature of FM contacts is a primary requirement for MoS2 based spintronics and therefore using directly grown MoS2 channels in the present study can pave a path towards high performance devices for large scale applications.

7.
Nanoscale ; 10(8): 4147, 2018 02 22.
Artículo en Inglés | MEDLINE | ID: mdl-29431827

RESUMEN

Correction for 'Band gap modification and photoluminescence enhancement of graphene nanoribbon filled single-walled carbon nanotubes' by A. I. Chernov et al., Nanoscale, 2018, DOI: 10.1039/c7nr07054c.

8.
Nanoscale ; 10(6): 2936-2943, 2018 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-29369315

RESUMEN

Molecule encapsulation inside the single-walled carbon nanotube (SWCNT) core has been demonstrated to be a successful route for the modification of nanotube properties. SWCNT diameter-dependent filling results in band gap modification together with the enhancement of photoluminescence quantum yield. However, the interaction between the inner structure and the outer shell is complex. It depends on the orientation of the molecules inside, the geometry of the host nanotube and on several other mechanisms determining the resulting properties of the hybrid nanosystem. In this work we study the influence of encapsulated graphene nanoribbons on the optical properties of the host single-walled carbon nanotubes. The interplay of strain and dielectric screening caused by the internal environment of the nanotube affects its band gap. The photoluminescence of the filled nanotubes becomes enhanced when the graphene nanoribbons are polymerized inside the SWCNTs at low temperatures. We show a gradual photoluminescence quenching together with a selective signal enhancement for exact nanotube geometries, specifically (14,6) and (13,8) species. A precise adjustment of the optical properties and an enhancement of the photoluminescence quantum yield upon filling for nanotubes with specific diameters were assigned to optimal organization of the inner structures.

9.
Leukemia ; 32(3): 626-632, 2018 03.
Artículo en Inglés | MEDLINE | ID: mdl-28914260

RESUMEN

High-dose methotrexate (Hd-MTX) therapy has recently been applied to the treatment of adult acute lymphoblastic leukemia (ALL) based on pediatric protocols; however, its effectiveness for adult ALL has not yet been confirmed in a rigorous manner. We herein conducted a randomized phase III trial comparing Hd-MTX therapy with intermediate-dose (Id)-MTX therapy. This study was registered at UMIN-CTR (ID: C000000063). Philadelphia chromosome (Ph)-negative ALL patients aged between 25 and 64 years of age were enrolled. Patients who achieved complete remission (CR) were randomly assigned to receive therapy containing Hd-MTX (3 g/m2) or Id-MTX (0.5 g/m2). A total of 360 patients were enrolled. The CR rate was 86%. A total of 115 and 114 patients were assigned to the Hd-MTX and Id-MTX groups, respectively. The estimated 5-year disease-free survival rate of the Hd-MTX group was 58%, which was significantly better than that of the Id-MTX group at 32% (P=0.0218). The frequencies of severe adverse events were not significantly different. We herein demonstrated the effectiveness and safety of Hd-MTX therapy for adult Ph-negative ALL. Our results provide a strong rationale for protocols containing Hd-MTX therapy being applied to the treatment of adult ALL.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamiento farmacológico , Leucemia-Linfoma Linfoblástico de Células Precursoras/mortalidad , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Biomarcadores de Tumor , Esquema de Medicación , Femenino , Humanos , Masculino , Metotrexato/administración & dosificación , Persona de Mediana Edad , Mutación , Leucemia-Linfoma Linfoblástico de Células Precursoras/diagnóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Inducción de Remisión , Análisis de Supervivencia , Resultado del Tratamiento , Adulto Joven
10.
Med Oral Patol Oral Cir Bucal ; 22(6): e788-e795, 2017 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-29053660

RESUMEN

BACKGROUND: Non-surgical treatment has generally been recommended for stage II medication-related osteonecrosis of the jaw (MRONJ) in preference to surgery. However, non-surgical treatment is not empirically effective. The aim of this study was to evaluate whether surgical or non-surgical treatment leads to better outcomes for stage II MRONJ. MATERIAL AND METHODS: In this retrospective study, surgery was performed in a total of 28 patients while 24 patients underwent non-surgical treatment. The outcomes of both treatment approaches after 6 months were evaluated and statistically compared. In addition, risk factors for surgical and non-surgical treatments were assessed for each. RESULTS: Surgical treatment in 25 patients (89.3%) resulted in success, with failure in 3 patients (10.7%). Non-surgical treatment was successful for 8 patients (33.3%) and failed in 16 patients (66.7%). There was therefore a significant difference between surgical and non-surgical treatment outcomes (P<0.01). Regarding risk factors, in non-surgical treatment primary diseases, medications, and drug holiday had a significant effect on outcomes (P<0.01). Risk factors for surgical treatment could not be clarified. CONCLUSIONS: Surgical treatment is more effective than non-surgical treatment for stage II MRONJ, and drug holiday, primary disease, and medication constitute risk factors in non-surgical treatment.


Asunto(s)
Enfermedades Maxilomandibulares/inducido químicamente , Enfermedades Maxilomandibulares/terapia , Osteonecrosis/inducido químicamente , Osteonecrosis/terapia , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Enfermedades Maxilomandibulares/cirugía , Masculino , Osteonecrosis/cirugía , Estudios Retrospectivos , Factores de Riesgo , Resultado del Tratamiento
11.
Rev Sci Instrum ; 86(7): 073511, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-26233387

RESUMEN

For the purpose of stable plasma equilibrium control and detailed analysis, it is essential to reconstruct an accurate plasma boundary on the poloidal cross section in tokamak devices. The Cauchy condition surface (CCS) method is a numerical approach for calculating the spatial distribution of the magnetic flux outside a hypothetical surface and reconstructing the plasma boundary from the magnetic measurements located outside the plasma. The accuracy of the plasma shape reconstruction has been assessed by comparing the CCS method and an equilibrium calculation in JT-60SA with a high elongation and triangularity of plasma shape. The CCS, on which both Dirichlet and Neumann conditions are unknown, is defined as a hypothetical surface located inside the real plasma region. The accuracy of the plasma shape reconstruction is sensitive to the CCS free parameters such as the number of unknown parameters and the shape in JT-60SA. It is found that the optimum number of unknown parameters and the size of the CCS that minimizes errors in the reconstructed plasma shape are in proportion to the plasma size. Furthermore, it is shown that the accuracy of the plasma shape reconstruction is greatly improved using the optimum number of unknown parameters and shape of the CCS, and the reachable reconstruction errors in plasma shape and locations of strike points are within the target ranges in JT-60SA.

12.
Nat Mater ; 14(8): 775-9, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26030306

RESUMEN

The recent discovery of possible high-temperature (T(c)) superconductivity over 65 K in a monolayer FeSe film on SrTiO3 (refs 1-6) triggered a fierce debate on how superconductivity evolves from bulk to film, because bulk FeSe crystal exhibits a T(c) of no higher than 10 K (ref. 7). However, the difficulty in controlling the carrier density and the number of FeSe layers has hindered elucidation of this problem. Here, we demonstrate that deposition of potassium onto FeSe films markedly expands the accessible doping range towards the heavily electron-doped region. Intriguingly, we have succeeded in converting non-superconducting films with various thicknesses into superconductors with T(c) as high as 48 K. We also found a marked increase in the magnitude of the superconducting gap on decreasing the FeSe film thickness, indicating that the interface plays a crucial role in realizing the high-temperature superconductivity. The results presented provide a new strategy to enhance and optimize T(c) in ultrathin films of iron-based superconductors.

13.
Radiat Prot Dosimetry ; 167(1-3): 365-9, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-25953793

RESUMEN

The accumulation of accident-derived radiocesium was investigated in nine water bodies located 300-700 km from the Fukushima Dai-ichi Nuclear Power Plant (FDNPP). (134)Cs from the accident was detected in surface sediment of five water bodies. The (134)Cs concentration, corrected to the time of the accident in 2011, was generally lower than that of (137)Cs, and its spatial pattern does not fully correspond to that of (137)Cs. These results suggest that radiocesium derived from both FDNPP and past global fallout can be separately observed and that the contributions of both sources are non-uniform within these sites. The (134)Cs inventory in surface sediments is smaller than its deposition, suggesting that almost all deposited (134)Cs remains within the catchment and/or a part has been discharged from the saline and brackish water bodies.


Asunto(s)
Radioisótopos de Cesio/análisis , Accidente Nuclear de Fukushima , Sedimentos Geológicos/química , Lagos/química , Ceniza Radiactiva/análisis , Contaminantes Radiactivos del Agua/análisis , Sedimentos Geológicos/análisis , Lagos/análisis , Aguas Salinas/química
14.
Eur J Cancer ; 51(8): 935-41, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25837882

RESUMEN

BACKGROUND: Chemotherapeutic regimens for elderly patients with metastatic colorectal cancer (mCRC), such as bevacizumab combined with 5-fluorouracil (5-FU) and leucovorin, often exclude oxaliplatin and irinotecan owing to the risk of toxicity. However, treatment with infusional 5-fluorouracil and leucovorin requires percutaneous port-catheter placement and other precautions, causing unnecessary stress for patients as well as healthcare workers. METHODS: We conducted a phase II study to evaluate the efficacy and safety of bevacizumab plus S-1 in elderly patients with previously untreated mCRC. Bevacizumab was given intravenously every two weeks, and S-1 was administered orally on days 1-28 of a 42-day cycle. The primary end-point was progression-free survival (PFS). The secondary end-points were time to treatment failure, response rate (RR), overall survival (OS), treatment completion status and safety. RESULTS: From October 2007 through March 2010, 56 patients were enroled. The median PFS was 9.9months, the median OS was 25.0months, and the RR was 57%. The main adverse events of grade 3 or higher were hypertension (11%), diarrhoea (9%) and neutropenia (7%). CONCLUSION: Our results suggest that combination chemotherapy with S-1 and bevacizumab can be administered safely and continuously on an outpatient basis and is therapeutically effective in elderly patients with mCRC.


Asunto(s)
Anciano , Anticuerpos Monoclonales Humanizados/administración & dosificación , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Carcinoma/tratamiento farmacológico , Neoplasias Colorrectales/tratamiento farmacológico , Ácido Oxónico/administración & dosificación , Tegafur/administración & dosificación , Anciano de 80 o más Años , Anticuerpos Monoclonales Humanizados/efectos adversos , Bevacizumab , Carcinoma/mortalidad , Carcinoma/patología , Neoplasias Colorrectales/mortalidad , Neoplasias Colorrectales/patología , Relación Dosis-Respuesta a Droga , Combinación de Medicamentos , Femenino , Humanos , Masculino , Metástasis de la Neoplasia , Ácido Oxónico/efectos adversos , Análisis de Supervivencia , Tegafur/efectos adversos , Resultado del Tratamiento
15.
Eur J Surg Oncol ; 41(3): 361-7, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25312685

RESUMEN

INTRODUCTION: Patients with muscle-invasive bladder cancer (MIBC) often undergo various preoperative treatments to improve survival; however, their efficacy and safety remain unclear. MATERIALS AND METHODS: The anti-tumour effects and adverse events were evaluated in 163 MIBC patients who received systemic chemotherapy (SC, n = 34), intra-arterial chemotherapy (IAC, n = 50), or combined IAC and radiotherapy (IAC + R, n = 79). RESULTS: Pathological complete responses were observed in 17.6%, 22.0%, and 43.0% of patients in the SC, IAC, and IAC + R groups, respectively, with respective 5-year overall survival rates of 42.0%, 46.7%, and 50.3%. Multivariate analysis showed that successful IAC + R protocol administration was a significant predictor for survival (hazard ratio = 0.16, p = 0.028). The incidence of severe adverse events was higher in the IAC + R group (36.7%) than in the SC (9.8%) and IAC groups (16.0%). CONCLUSIONS: IAC + R was useful for patients with MIBC. Successful completion and optimal patient selection were important for this treatment strategy.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Carcinoma de Células Transicionales/terapia , Neoplasias de la Vejiga Urinaria/terapia , Vejiga Urinaria/patología , Anciano , Anciano de 80 o más Años , Carboplatino/administración & dosificación , Carcinoma de Células Transicionales/patología , Quimioradioterapia , Quimioradioterapia Adyuvante , Quimioterapia Adyuvante , Cisplatino/administración & dosificación , Cistectomía , Femenino , Fluorouracilo/administración & dosificación , Humanos , Infusiones Intraarteriales , Masculino , Persona de Mediana Edad , Análisis Multivariante , Terapia Neoadyuvante/métodos , Invasividad Neoplásica , Tratamientos Conservadores del Órgano , Peplomicina/administración & dosificación , Pronóstico , Resultado del Tratamiento , Neoplasias de la Vejiga Urinaria/patología
16.
Phys Rev Lett ; 113(23): 237001, 2014 Dec 05.
Artículo en Inglés | MEDLINE | ID: mdl-25526150

RESUMEN

We have performed high-resolution angle-resolved photoemission spectroscopy on an FeSe superconductor (T_{c}∼8 K), which exhibits a tetragonal-to-orthorhombic structural transition at T_{s}∼90 K. At low temperature, we found splitting of the energy bands as large as 50 meV at the M point in the Brillouin zone, likely caused by the formation of electronically driven nematic states. This band splitting persists up to T∼110 K, slightly above T_{s}, suggesting that the structural transition is triggered by the electronic nematicity. We have also revealed that at low temperature the band splitting gives rise to a van Hove singularity within 5 meV of the Fermi energy. The present result strongly suggests that this unusual electronic state is responsible for the unconventional superconductivity in FeSe.


Asunto(s)
Compuestos de Hierro/química , Selenio/química , Conductividad Eléctrica , Espectroscopía de Fotoelectrones/métodos , Termodinámica
17.
Placenta ; 35(8): 658-60, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-24969759

RESUMEN

The purpose of this study is to assess the role of the protein kinase A (PKA) in regulating uptake of dehydroepiandrosterone sulfate (DHEAS), an estrogen precursor, by syncytiotrophoblasts. Forskolin, a PKA activator, significantly increased [(3)H]DHEAS uptake and the mRNA expression levels of organic anion transporter (OAT) 4 and CYP19A1 in choriocarcinoma JEG-3 cells, while other steroid sulfate transporters present in the placenta showed no change in expression level. KT5720, a PKA inhibitor, attenuated these effects of forskolin. Accordingly, the PKA pathway appears to play an important role in estrogen synthesis by cooperatively regulating OAT4 and steroidogenic enzymes in syncytiotrophoblasts.


Asunto(s)
Proteínas Quinasas Dependientes de AMP Cíclico/metabolismo , Sulfato de Deshidroepiandrosterona/metabolismo , Estrógenos/biosíntesis , Trofoblastos/metabolismo , Línea Celular Tumoral , Humanos , Transportadores de Anión Orgánico Sodio-Independiente/metabolismo
18.
Ann Oncol ; 24(9): 2376-81, 2013 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-23788749

RESUMEN

BACKGROUND: To better describe clinical T descriptors using solid tumor size (the maximum dimension of the solid component of the tumor) on high-resolution computed tomography (HRCT) and maximum standardized uptake value (SUVmax) on F-18-fluorodeoxyglucose positron emission tomography/CT (FDG-PET/CT). PATIENTS AND METHODS: We examined 610 consecutive patients with clinical stage IA lung adenocarcinoma who underwent complete resection. Recurrence-free survival (RFS) was assessed on the basis of whole tumor size (maximum dimension of the tumor), solid tumor size, or a combination of solid tumor size and SUVmax. RESULTS: RFS based on whole tumor size was not significantly different between patients with tumors measuring ≤2 cm and 2-3 cm (P = 0.089), whereas RFS based on solid tumor size was significantly different (P < 0.0001). We divided patients into four groups on the basis of solid tumor size and SUVmax: group 1: solid tumor size ≤2 cm, SUVmax ≤1.8; group 2: solid tumor size ≤2 cm, SUVmax >1.8; group 3: solid tumor size 2-3 cm, SUVmax ≤3.6; and group 4: solid tumor size 2-3 cm, SUVmax >3.6. Groups 2 and 3 were combined because they showed similar RFS each other. RFS was significantly different among these groups: group 1 versus groups 2 + 3, P < 0.0001; groups 2 + 3 versus group 4, P = 0.019. CONCLUSIONS: Both solid tumor size on HRCT and SUVmax on FDG-PET/CT reflect prognosis well in patients with clinical stage IA lung adenocarcinoma and may support new clinical T descriptors.


Asunto(s)
Adenocarcinoma/diagnóstico por imagen , Neoplasias Pulmonares/diagnóstico por imagen , Tomografía de Emisión de Positrones , Tomografía Computarizada por Rayos X , Adenocarcinoma/cirugía , Adenocarcinoma del Pulmón , Adulto , Anciano , Anciano de 80 o más Años , Supervivencia sin Enfermedad , Femenino , Humanos , Neoplasias Pulmonares/cirugía , Masculino , Persona de Mediana Edad , Invasividad Neoplásica/diagnóstico por imagen , Estadificación de Neoplasias
19.
Sci Rep ; 3: 1617, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23563618

RESUMEN

Graphene nanoribbons (GNR) are one of the most promising candidates for the fabrication of graphene-based nanoelectronic devices such as high mobility field effect transistors (FET). Here, we report a high-yield fabrication of a high quality another type of GNR analogue, fully flattened carbon nanotubes (flattened CNTs), using solution-phase extraction of inner tubes from large-diameter multi-wall CNTs (MWCNTs). Transmission electron microscopy (TEM) observations show that flattened CNTs have width of typically 20 nm and a barbell-like cross section. Measurements of the low-bias conductance of isolated flattened CNTs as a function of gate voltage shows that the flattened CNTs display ambipolar conduction which is different from those of MWCNTs. The estimated gap based on temperature dependence of conductivity measurements of isolated flattened CNTs is 13.7 meV, which is probably caused by the modified electronic structure due to the flattening.


Asunto(s)
Grafito/química , Nanotecnología/instrumentación , Nanotubos de Carbono/química , Transistores Electrónicos , Cristalización/métodos , Diseño de Equipo , Análisis de Falla de Equipo , Ensayo de Materiales , Nanotubos de Carbono/ultraestructura , Tamaño de la Partícula
20.
J Oral Rehabil ; 40(5): 368-74, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-23438017

RESUMEN

Gender-related risk factors in the survival of transplanted teeth with complete root formation have not yet been identified. The purpose of this study was to investigate gender differences in tooth autotransplantation at dental clinics. We asked participating dentists to provide information on transplantations they had undertaken from 1 January 1990 to 1931 December 2010. The data were screened to exclude patients who underwent more than one transplantation, smokers or those whose smoking habits were unknown, patients under 30 or who were 70 years old and over, cases where the transplanted teeth had incomplete root formation or multiple roots and those with fewer than 20 present teeth post-operation. We analysed 73 teeth of 73 males (mean age, 47.2 years) and 106 teeth of 106 females (mean age, 45.3 years) in this study. The cumulative survival rate and mean survival time were calculated using the Kaplan-Meier method. The cumulative survival rate for males was 88.3% at the 5-year mark, 64.8% at 10 years and 48.6% at 15 years; for females, it was 97.2% at the 5-year mark, 85.9% at 10 years and 85.9% at 15 years. A log-rank test indicated the difference between males and females to be significant (P = 0.011). There was also a significant difference in the main causes for the loss of transplanted teeth: males lost more transplanted teeth due to attachment loss than females (P < 0.05). These results indicate that males require more attention during the autotransplantation process, particularly at the stage of pre-operation evaluation and that of follow-up maintenance.


Asunto(s)
Raíz del Diente/anatomía & histología , Diente/trasplante , Adulto , Anciano , Diente Premolar/patología , Diente Premolar/trasplante , Femenino , Estudios de Seguimiento , Supervivencia de Injerto , Humanos , Masculino , Persona de Mediana Edad , Diente Molar/patología , Diente Molar/trasplante , Odontogénesis/fisiología , Pérdida de la Inserción Periodontal/complicaciones , Pronóstico , Estudios Retrospectivos , Factores de Riesgo , Factores Sexuales , Factores de Tiempo , Pérdida de Diente/etiología , Trasplante Autólogo , Resultado del Tratamiento
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...