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1.
Molecules ; 29(4)2024 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-38398598

RESUMO

The effects of solution concentration and pH on the formation and surface structure of 2-pyrimidinethiolate (2PymS) self-assembled monolayers (SAMs) on Au(111) via the adsorption of 2,2'-dipyrimidyl disulfide (DPymDS) were examined using scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). STM observations revealed that the formation and structural order of 2PymS SAMs were markedly influenced by the solution concentration and pH. 2PymS SAMs formed in a 0.01 mM ethanol solution were mainly composed of a more uniform and ordered phase compared with those formed in 0.001 mM or 1 mM solutions. SAMs formed in a 0.01 mM solution at pH 2 were composed of a fully disordered phase with many irregular and bright aggregates, whereas SAMs formed at pH 7 had small ordered domains and many bright islands. As the solution pH increased from pH 7 to pH 12, the surface morphology of 2PymS SAMs remarkably changed from small ordered domains to large ordered domains, which can be described as a (4√2 × 3)R51° packing structure. XPS measurements clearly showed that the adsorption of DPymDS on Au(111) resulted in the formation of 2PymS (thiolate) SAMs via the cleavage of the disulfide (S-S) bond in DPymDS, and most N atoms in the pyrimidine rings existed in the deprotonated form. The results herein will provide a new insight into the molecular self-assembly behaviors and adsorption structures of DPymDS molecules on Au(111) depending on solution concentration and pH.

2.
Diagnostics (Basel) ; 13(15)2023 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-37568908

RESUMO

Patients undergoing dialysis through a permanent catheter often experience infection or malfunction. However, few studies have clarified the predictors of permanent catheter patency survival in patients undergoing hemodialysis. We assessed the relationship between the parameters of body composition monitoring (BCM), determined before the initiation of dialysis, and the patency survival of the permanent catheters inserted in 179 patients who commenced hemodialysis between 14 January 2020 and 31 August 2021. The relationships between permanent catheter patency at 6 weeks and BCM parameters, laboratory tests, age, sex, comorbidities, and medications at baseline were studied using Kaplan-Meier survival curves. Permanent catheter patency was observed to be superior at high extracellular-to-intracellular (ECW/ICW) ratio (p < 0.005). After adjustment for covariates, the ECW/ICW ratio remained an independent factor associated with permanent catheter patency survival. When patients with non-patent catheters were subdivided into infection and malfunction groups, and the associations of BCM parameters were evaluated in those groups, the ECW/ICW ratio was not significantly associated with permanent catheter patency survival in the infection group (p = 0.327); instead, a significant association was found for the lean tissue index (p < 0.001). In the malfunction group, the ECW/ICW ratio remained significantly associated with permanent catheter patency survival (p < 0.001).

3.
Diagnostics (Basel) ; 13(4)2023 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-36832265

RESUMO

For reducing the high mortality rate of severe acute kidney injury (AKI) patients initiating continuous renal replacement therapy (CRRT), diagnosing sepsis and predicting prognosis are essential. However, with reduced renal function, biomarkers for diagnosing sepsis and predicting prognosis are unclear. This study aimed to assess whether C-reactive protein (CRP), procalcitonin, and presepsin could be used to diagnose sepsis and predict mortality in patients with impaired renal function initiating CRRT. This was a single-center, retrospective study involving 127 patients who initiated CRRT. Patients were divided into sepsis and non-sepsis groups according to the SEPSIS-3 criteria. Of the 127 patients, 90 were in the sepsis group and 37 were in the non-sepsis group. Cox regression analysis was performed to determine the association between the biomarkers (CRP, procalcitonin, and presepsin) and survival. CRP and procalcitonin were superior to presepsin for diagnosing sepsis. Presepsin was closely related to the estimated glomerular filtration rate (eGFR) (r = -0.251, p = 0.004). These biomarkers were also evaluated as prognostic markers. Procalcitonin levels ≥3 ng/mL and CRP levels ≥31 mg/L were associated with higher all-cause mortality using Kaplan-Meier curve analysis. (log-rank test p = 0.017 and p = 0.014, respectively). In addition, procalcitonin levels ≥3 ng/mL and CRP levels ≥31 mg/L were associated with higher mortality in univariate Cox proportional hazards model analysis. In conclusion, a higher lactic acid, sequential organ failure assessment score, eGFR, and a lower albumin level have prognostic value to predict mortality in patients with sepsis initiating CRRT. Moreover, among these biomarkers, procalcitonin and CRP are significant factors for predicting the survival of AKI patients with sepsis-initiating CRRT.

4.
Environ Sci Technol ; 56(24): 17581-17590, 2022 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-36459099

RESUMO

Although the particle phase state is an important property, there is scant information on it, especially, for real-world aerosols. To explore the phase state of fine mode aerosols (PM2.5) in two megacities, Seoul and Beijing, we collected PM2.5 filter samples daily from Dec 2020 to Jan 2021. Using optical microscopy combined with the poke-and-flow technique, the phase states of the bulk of PM2.5 as a function of relative humidity (RH) were determined and compared to the ambient RH ranges in the two cities. PM2.5 was found to be liquid to semisolid in Seoul but mostly semisolid to solid in Beijing. The liquid state was dominant on polluted days, while a semisolid state was dominant on clean days in Seoul. These findings can be explained by the aerosol liquid water content related to the chemical compositions of the aerosols at ambient RH; the water content of PM2.5 was much higher in Seoul than in Beijing. Furthermore, the overall phase states of PM2.5 observed in Seoul and Beijing were interrelated with the particle size distribution. The results of this study aid in a better understanding of the fundamental physical properties of aerosols and in examining how these are linked to PM2.5 in polluted urban atmospheres.


Assuntos
Poluentes Atmosféricos , Material Particulado , Pequim , Material Particulado/análise , Cidades , Poluentes Atmosféricos/análise , Tamanho da Partícula , Seul , Monitoramento Ambiental/métodos , Estações do Ano , Água , Aerossóis/análise , China
5.
Diagnostics (Basel) ; 11(10)2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34679605

RESUMO

Accurate dry weight (DW) estimation is important for hemodialysis patients. Although bioimpedance spectroscopy (BIS) is commonly used to measure DW, the BIS-based DW frequently differs from the clinical DW. We analyzed the characteristics of patients whose BIS-based DWs were over- and underestimated. In this retrospective cohort study, we evaluated 1555 patients undergoing maintenance hemodialysis in Chungnam National University Hospital. The gap (DWCP-BIS) was calculated by comparing the BIS and clinical DWs. We analyzed the clinical characteristics of patients with positive (n = 835) and negative (n = 720) gaps. Compared with other patients, the DWCP-BIS-positive group had higher extracellular water (ECW) level and extracellular/intracellular water index (E/I) and had lower weight, body mass index (BMI), lean tissue index (LTI), fat tissue index (FTI), fat mass (FAT), and adipose tissue mass (ATM). The DWCP-BIS-negative group exhibited elevated BMI, FTI, FAT, and ATM; however, it had lower height, ECW, and E/I. Linear regression analysis revealed that FAT significantly predicted DWCP accuracy. The clinical DW of patients with a low fat mass tended to be underestimated, while the clinical DW of patients with comparatively large fat reserves tended to be overestimated. These characteristics will aid in the reduction of BIS-based DW errors.

6.
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.

7.
Int J Mol Sci ; 21(9)2020 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-32403422

RESUMO

In tissue engineering, biocompatible scaffolds are used as 3D cell niches to provide a similar environment to that of native tissue for seeded cells to regenerate the target tissue. When engineering bone tissue, high mechanical strength and calcium phosphate composition are essential factors to consider. In this study, we fabricated biocompatible composite scaffolds composed of synthetic polymers (polycaprolactone (PCL) and poly (vinyl alcohol) (PVA)), natural polymers (gelatin and collagen) and bioceramic (hydroxyapatite; HA) for bone tissue engineering. The synthetic polymers were used to enhance the mechanical properties of the composite scaffolds while the natural protein-based polymers were used to enhance various cellular activities, such as cell adhesion and proliferation. Meanwhile, the bioceramic was introduced to promote osteogenic differentiation. Composite scaffolds were evaluated for their physical characteristics, such as mechanical, swelling and protein absorbing properties as well as biological properties (cell proliferation, alkaline phosphatase (ALP) activities and calcium deposition) with human osteoblast-like cells (MG63). Consequently, incorporation of hydroxyapatite into the gelatin/PVA (C-GPH) scaffold showed 5-fold and 1.5-fold increase in calcium deposition and ALP activities, respectively compared to gelatin/PVA scaffold (C-GP). Moreover, compressive modulus also increased 1.8-fold. Integration of PCL core into gelatin/PVA/hydroxyapatite scaffold (C-PGPH) further amplified the compressive modulus 1.5-fold. In conclusion, the scaffold that is reinforced with HA particles and integrated with PCL core of the struts showed significant potential in field of bone tissue engineering.


Assuntos
Materiais Biocompatíveis/química , Osso e Ossos/fisiologia , Durapatita/química , Gelatina/química , Engenharia Tecidual/métodos , Alicerces Teciduais/química , Materiais Biocompatíveis/farmacologia , Osso e Ossos/citologia , Osso e Ossos/efeitos dos fármacos , Fosfatos de Cálcio/química , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Humanos , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Osteoblastos/fisiologia , Osteogênese/efeitos dos fármacos , Poliésteres/química , Porosidade , Impressão Tridimensional
8.
Int J Biol Macromol ; 135: 21-28, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31100404

RESUMO

The surface topography of a tissue-engineered scaffold is widely known to play an essential role in bone tissue engineering applications. Therefore, the cell-to-material interaction should be considered when developing scaffolds for bone tissue regeneration. Bone is a dynamic tissue with a distinct hierarchical structure composed of mostly collagen and bioceramics. In this study, the surface of gelatin/PVA scaffold (CF-G5P5) coated with fibrillated collagen was fabricated to enhance cell proliferation and osteogenic differentiation for bone tissue regeneration. The physical and biological properties of the fabricated scaffolds were investigated. As a result, the CF-G5P5 scaffold increased surface roughness and increased protein absorption compared to a gelatin/PVA scaffold (G5P5) by 1.6 times from OD value 0.43 to 0.71 after 12 h, cell proliferation increased 1.7 times from OD value 0.57 to 0.96, and differentiation increased by 1.5 times from 100 to 151%. Based on the results, the CF-G5P5 scaffold developed can be considered as a highly potential bone tissue regenerative material.


Assuntos
Colágeno/química , Gelatina/química , Nanofibras/química , Álcool de Polivinil/química , Alicerces Teciduais/química , Biomarcadores , Regeneração Óssea , Linhagem Celular , Sobrevivência Celular , Matriz Extracelular/metabolismo , Fenômenos Mecânicos , Nanofibras/ultraestrutura , Análise Espectral , Propriedades de Superfície , Engenharia Tecidual
9.
Int J Biol Macromol ; 120(Pt A): 119-127, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30056041

RESUMO

Tissue engineering aims to repair or replace damaged tissues or organs using biomedical scaffolds cultured with cells. The scaffolds composed of biomaterials should guide the cells to mature into functional tissues or organs. An ideal scaffold to regenerate hard tissues should have mechanical stability as well as biocompatibilities. It has been well known that gelatin can provide outstanding biological activities, but its low mechanical stability can be one of obstacles to be used in hard tissue regeneration. To overcome the issue, we used PVA, which can reinforce the low mechanical stability of the gelatin. The gelatin/PVA scaffolds have been fabricated using a low temperature 3D-printing process. By manipulating various weight fractions of PVA/gelatin, we can obtain the optimal mixture ratio in aspect of the physical and biological properties of the scaffolds. As a result, a weight fraction of 5:5 showed appropriate mechanical strength and enhanced cell activities, such as cell proliferation and differentiation. The gelatin/PVA scaffold showed potential for future application as biomedical scaffold in soft and hard tissue regeneration.


Assuntos
Gelatina/química , Teste de Materiais , Álcool de Polivinil/química , Impressão Tridimensional , Regeneração , Alicerces Teciduais/química , Diferenciação Celular , Linhagem Celular , Proliferação de Células , Humanos
10.
J Phys Condens Matter ; 30(10): 105601, 2018 03 14.
Artigo em Inglês | MEDLINE | ID: mdl-29380748

RESUMO

Hexagonal manganites are multiferroic materials with two highly-dissimilar phase transitions: a ferroelectric transition (from P63/mmc to P63cm) at a temperature higher than 1000 K and an antiferromagnetic transition at T N = 65-130 K. Despite its critical relevance to the intriguing ferroelectric domain physics, the details of the ferroelectric transition are not well known to date primarily because of the ultra-high transition temperature. Using high-temperature x-ray diffraction experiments, we show that the ferroelectric transition is a single transition of abrupt order and R-Op displacement is the primary order parameter. This structural transition is then simultaneously accompanied by MnO5 tilting and the subsequent development of electric polarization.

11.
Chemphyschem ; 19(3): 261-265, 2018 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-29143420

RESUMO

CuIn1-x Gax S2-y Sey (CIGSSe) thin films have attracted a great deal of attention as promising absorbing materials for solar cell applications, owing to their favorable optical properties (e.g. a direct band gap and high absorption coefficients) and stable structure. Many studies have sought to improve the efficiency of solar cells using these films, and it has been found that surface modification through post-heat treatment can lead to surface passivation of surface defects and a subsequent increase in efficiency. The surface properties of solution-processed CIGSSe films are considered to be particularly important in this respect, owing to the fact that they are more prone to defects. In this work, CIGSSe thin films with differing S/Se ratios at their surface were synthesized by using a precursor solution and post-sulfurization heat treatment. These CIGSSe thin films were investigated with current-voltage and Kelvin probe force microscope (KPFM) analyses. Surface photovoltage (SPV), which is the difference in the work function in the dark and under illumination, was measured by using KPFM, which can examine the screening and the modification of surface charge through carrier trapping. As the concentration of S increases on the CIGSSe film surface, higher work functions and more positive SPV values were observed. Based on these measurements, we inferred the band-bending behavior of CIGSSe absorber films and proposed reasons for the improvement in solar cell performance.

12.
Restor Dent Endod ; 42(1): 27-33, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28194361

RESUMO

OBJECTIVES: To determine the optimal timing for post space preparation of root canals sealed with epoxy resin-based AH Plus sealer in terms of its polymerization and influence on apical leakage. MATERIALS AND METHODS: The epoxy polymerization of AH Plus (Dentsply DeTrey) as a function of time after mixing (8, 24, and 72 hours, and 1 week) was evaluated using Fourier transform infrared (FTIR) spectroscopy and microhardness measurements. The change in the glass transition temperature (Tg ) of the material with time was also investigated using differential scanning calorimetry (DSC). Fifty extracted human single-rooted premolars were filled with gutta-percha and AH Plus, and randomly separated into five groups (n = 10) based on post space preparation timing (immediately after root canal obturation and 8, 24, and 72 hours, and 1 week after root canal obturation). The extent of apical leakage (mm) of the five groups was compared using a dye leakage test. Each dataset was statistically analyzed by one-way analysis of variance and Tukey's post hoc test (α = 0.05). RESULTS: Continuous epoxy polymerization of the material with time was observed. Although the Tg values of the material gradually increased with time, the specimens presented no clear Tg value at 1 week after mixing. When the post space was prepared 1 week after root canal obturation, the leakage was significantly higher than in the other groups (p < 0.05), among which there was no significant difference in leakage. CONCLUSIONS: Poor apical seal was detected when post space preparation was delayed until 1 week after root canal obturation.

13.
ChemSusChem ; 9(16): 2097-102, 2016 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-27466025

RESUMO

The formation of a nanostructure is a popular strategy for catalyst applications because it can generate new surfaces that can significantly improve the catalytic activity and durability of the catalysts. However, the increase in the surface area resulting from nanostructuring does not fully explain the substantial improvement in the catalytic properties of the CO2 electroreduction reaction, and the underlying mechanisms have not yet been fully understood. Here, based on a combination of extended X-ray absorption fine structure analysis, X-ray photoelectron spectroscopy, and Kelvin probe force microscopy, we observed a contracted Au-Au bond length and low work function with the nanostructured Au surface that had enhanced catalytic activity for electrochemical CO2 reduction. The results may improve the understanding of the enhanced stability of the nanostructured Au electrode based on the resistance of cation adhesion during the CO2 reduction reaction.


Assuntos
Dióxido de Carbono/química , Ouro/química , Nanoestruturas/química , Catálise , Eletroquímica , Eletrodos , Oxirredução , Propriedades de Superfície
14.
ACS Appl Mater Interfaces ; 7(44): 24550-5, 2015 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-26489005

RESUMO

Oxygen evolution reaction (OER) is the key reaction in electrochemical processes, such as water splitting, metal-air batteries, and solar fuel production. Herein, we developed a facile chemical solution deposition method to prepare a highly active Co3O4 thin film electrode for OER, showing a low overpotential of 377 mV at 10 mA/cm(2) with good stability. An optimal loading of ethyl cellulose additive in a precursor solution was found to be essential for the morphology control and thus its electrocatalytic activity. Our results also show that the distribution of Co3O4 nanoparticle catalysts on the substrate is crucial in enhancing the inherent OER catalytic performance.

15.
Sci Rep ; 5: 8531, 2015 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-25704566

RESUMO

Pd nanoparticle (NP) coated LaAlO3/SrTiO3 (LAO/STO) heterointerface exhibits more notable conductance (G) change while varying the ambient gas (N2, H2/N2, and O2) and illuminating with UV light (wavelength: 365 nm) than a sample without the NPs. Simultaneous Kelvin probe force microscopy and transport measurements reveal close relationships between the surface work function (W) and G of the samples. Quantitative analyses suggest that a surface adsorption/desorption-mediated reaction and redox, resulting in a band-alignment modification and charge-transfer, could explain the gas- and photo-induced conductance modulation at the LAO/STO interface. Such surface-and-interface coupling enhanced by catalytic Pd NPs is a unique feature, quite distinct from conventional semiconductor hetero-junctions, which enables the significant conductance tunability at ultrathin oxide heterointerfaces by external stimuli.

16.
Ultrasound Med Biol ; 40(12): 2851-6, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25308944

RESUMO

We aimed to investigate whether a cylindrical structure containing either air or fluid and with or without a metallic stent affects the volume and density of cavitation produced by high-intensity focused ultrasound via a gel phantom study. Sixteen tissue-mimicking phantoms based on a polyacrylamide gel mixed with bovine serum albumin with a cylindrical hole 1 cm in diameter and 7.5 cm in length were divided into four groups of four phantoms with air in the holes (group 1), four phantoms with fluid in the holes (group 2), four phantoms with air-containing metallic stents (group 3) and four phantoms with fluid-containing metallic stents (group 4). A pulsed high-intensity focused ultrasound beam (50% duty cycle, 40-Hz pulse repetition frequency) at 75 W of acoustic power was directed perpendicularly to the longitudinal axis of the hole, with its focus at the posterior wall of the hole. The size of the cavitation on the x-, y-, and z-axes was measured, and the volumes of cavitation and coagulation were calculated using the formula for the volume of an elliptical cone. The density of cavitation was measured in the tissue phantom anterior to the hole with a 1 × 1-cm square region of interest. For statistical analysis, the Kruskal-Wallis test and Mann-Whitney U-test were used. The phantoms with air-containing holes (groups 1 and 3) developed larger and denser cavitations anterior to the focus, without unnecessary coagulation posterior to the focus, compared with the phantoms with fluid-containing holes (groups 2 and 4), regardless of the presence of stents. All of the axes and volumes of the anterior cavitations were significantly larger than those of the posterior cavitations in groups 1 and 3 (all p-values <0.05). The results of this study might be applied to maximize cavitation to enhance drug delivery into tumors.


Assuntos
Ar , Materiais Biomiméticos/química , Materiais Biomiméticos/efeitos da radiação , Ablação por Ultrassom Focalizado de Alta Intensidade , Metais/química , Stents , Géis/química , Géis/efeitos da radiação , Ondas de Choque de Alta Energia , Metais/efeitos da radiação , Imagens de Fantasmas , Doses de Radiação , Espalhamento de Radiação , Soroalbumina Bovina/química , Soroalbumina Bovina/efeitos da radiação
17.
ACS Appl Mater Interfaces ; 6(16): 14037-42, 2014 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-25004117

RESUMO

We investigated the influences of charge writing on the surface work function (W) and sheet resistance (R) of the LaAlO3/SrTiO3 (LAO/STO) heterointerface in several gas environments: H2(2%)/N2(98%), air, N2, and O2. The decrease in W and R due to charge writing was much larger in air (ΔW = -0.45 eV and ΔR = -40 kΩ/S) than in O2 (ΔW = -0.21 eV and ΔR = -19 kΩ/S). The reduced R could be maintained more than 100 h in H2/N2. Such distinct behaviors were quantitatively discussed, based on the proposed charge-writing mechanisms. Such analyses showed how several processes, such as carrier transfer via surface adsorbates, surface redox, electronic state modification, and electrochemical surface reactions, contributed to charge writing in each gas.

18.
Eur Radiol ; 24(9): 2059-68, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24962825

RESUMO

PURPOSE: To assess therapeutic efficacy of gemcitabine and HIFU for a mouse model of pancreatic cancer, and the role of DCE-US for predicting early treatment response compared with pathology. MATERIALS AND METHODS: In 48 PANC-1- nude mice (G1, HIFU_higher power [n = 14]; G2, gemcitabine [n = 12]; G3, combined gemcitabine and HIFU_low power [n = 12]; and G4, control [n = 10]), pulsed HIFU or gemcitabine therapy was used. DCE-US was performed 1 day before and after first treatment. Seven DCE-US perfusion parameters were obtained. Therapeutic efficacy was estimated using necrotic fraction and apoptosis. Correlation between tumour size and US perfusion parameters was analysed. RESULTS: Pathology results showed that combined gemcitabine and HIFU using low-power treatment had a more effective response than other treatments, including in the control group, i.e. necrotic fraction: 40.5 ± 4.9 vs. 16.9 ± 8.0, p = 0.000 and apoptosis: 44.3 ± 29.4 vs. 7.9 ± 4.9, p = 0.002. In this group, US perfusion parameters, including peak intensity (22.6 ± 22.6 vs. 9.6 ± 6.3, p = 0.002), AUC (961.8 ± 96.9 vs. 884.4 ± 91.4, p = 0.000), and AUCout (799.9 ± 75.6 vs. 747.1 ± 77.9, p = 0.000), had significantly decreased 1 day following first treatment (p < 0.05). In addition, peak intensity, AUC, and AUCout showed a tendency to decrease in treated groups. Alternatively, peak intensity, AUC, and AUCout showed a tendency to increase in control group. CONCLUSION: Gemcitabine and HIFU were more effective and safer than other treatments. US perfusion parameters were useful for predicting early therapeutic response 1 day following treatment. KEY POINTS: Recently, treatment of pancreatic cancer has changed based on a multidisciplinary approach. Combined gemcitabine_HIFU demonstrated more effective therapeutic response than other treatments. DCE-US is useful for predicting early therapeutic response 1 day after treatment. In the combined group, PI, AUC, and AUC (out) decreased 1 day after treatment.


Assuntos
Meios de Contraste , Desoxicitidina/análogos & derivados , Ablação por Ultrassom Focalizado de Alta Intensidade/métodos , Neoplasias Experimentais , Neoplasias Pancreáticas/diagnóstico por imagem , Animais , Desoxicitidina/uso terapêutico , Xenoenxertos , Humanos , Imunossupressores/uso terapêutico , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Neoplasias Pancreáticas/tratamento farmacológico , Neoplasias Pancreáticas/cirurgia , Ribonucleotídeo Redutases/antagonistas & inibidores , Transplante Heterólogo , Resultado do Tratamento , Ultrassonografia , Gencitabina , Neoplasias Pancreáticas
19.
ACS Appl Mater Interfaces ; 5(22): 11668-72, 2013 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-24152094

RESUMO

A nanoscale Schottky diode using Pt nanodisks on a Nb-doped SrTiO3 (Nb:STO) single crystal was fabricated, and resistive switching (RS) was demonstrated with conductive atomic force microscopy at ultrahigh vacuum. Pt disks with diameters on the order of 10 nm were formed using colloidal self-assembled patterns of silica nanospheres, followed by evaporation of the Pt layers on the Nb:STO single crystal. Here we show that the reproducible bipolar RS behavior of the nanoscale Pt/Nb:STO Schottky junction was achieved by utilizing local current-voltage spectroscopy. The conductance images, obtained simultaneously with topographic images, show the homogeneous current distribution of selected triangular-shaped Pt nanodisks during repetitive resistive switching between the high-resistance state (HRS) and low-resistance state (LRS). The endurance characteristics of the Pt/Nb:STO junction exhibit reliable switching behavior. These results suggest that the rectifying and resistive Pt/Nb:STO junction can be scaled down to the 10 nm range and their position can be controlled.

20.
Ultrasound Med Biol ; 39(11): 1991-2000, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23972483

RESUMO

We sought to investigate whether concurrent exposure to pulsed high-intensity focused ultrasound (HIFU) and the chemotherapeutic drug gemcitabine would enhance apoptosis in pancreatic cancer. A pancreatic cancer xenograft model was established using BALB/c nude mice and human pancreatic cancer cells (PANC-1). In the first study, mice were randomly allocated into one of four groups: control (n = 4), HIFU alone (n = 4), gemcitabine (GEM) alone (n = 28) and concurrent treatment with HIFU and gemcitabine (HIGEM) (n = 28). The GEM and HIGEM groups were subdivided into four subgroups (16 mice) according to the drug dose injected (50-200 mg/kg) and another four subgroups (16 mice) according to the time interval between drug injection and HIFU treatment (each subgroup, n = 4). Apoptosis rates were evaluated using the TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling) assay and percentage of necrosis, as evaluated with Harris' hematoxylin solution and eosin Y stain, 3 d after treatment. The second study was performed to evaluate tumor growth rates of the four groups. Each group was treated weekly for 3 wk, and tumor size was periodically measured for up to 4 wk from the beginning of treatment. In the first study, overall rates of apoptosis were significantly higher in the HIGEM group than in the GEM group (p = 0.02). In a subgroup analysis, HIGEM was superior to GEM in enhancing apoptosis at gemcitabine dosages of 150-200 mg/kg gemcitabine and intervals between gemcitabine and HIFU less than 2 h (p = 0.01). In the second study, HIGEM treatment resulted in the slowest tumor growth. However, despite a visible distinction, none of the differences found between the HIGEM and GEM groups were statistically significant (p > 0.05). Treatment with both HIFU and gemcitabine might enhance cell apoptosis and reduce tumor growth in pancreatic carcinoma. For this concurrent treatment, a high dosage of gemcitabine and a short-term delay before HIFU are recommended to maximize the therapeutic effect.


Assuntos
Desoxicitidina/análogos & derivados , Ablação por Ultrassom Focalizado de Alta Intensidade/métodos , Neoplasias Pancreáticas/fisiopatologia , Neoplasias Pancreáticas/terapia , Animais , Antimetabólitos Antineoplásicos/uso terapêutico , Apoptose/efeitos dos fármacos , Apoptose/efeitos da radiação , Linhagem Celular Tumoral , Desoxicitidina/uso terapêutico , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Neoplasias Pancreáticas/patologia , Resultado do Tratamento , Gencitabina
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