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1.
Chemphyschem ; 20(1): 70-77, 2019 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-30347503

RESUMO

Composite materials consisting of nanoscale gold particles and protective polymer shells were designed and tested as catalysts in various chemical reactions. Initially, the systematic incorporation of multiple gold nanoparticles into a poly(N-isopropylacrylamide) particle was achieved by an in situ method under light irradiation. The degree of gold nanoparticle loading, along with the structural and morphological properties, was examined as a function of the amount of initial gold ions and reducing agent. As these gold nanoparticles were physically-embedded within the polymer particle in the absence of strong interfacial interactions between the gold nanoparticles and polymer matrix, the readily-accessible surface of the gold nanoparticles with a highly increased stability allowed for their use as recyclable catalysts in oxidation, reduction, and coupling reactions. Overall, the ability to integrate catalytically-active metal nanoparticles within polymer particles in situ allows for designing novel composite materials for multi-purpose catalytic systems.

2.
Nanotechnology ; 28(2): 025601, 2017 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-27905318

RESUMO

The in situ formation of dielectric silica (SiO2) particles was carried out in the presence of temperature-responsive poly(N-isopropylacrylamide) particles. Unlike the typical sol-gel method used to prepare various SiO2 particles, the highly uniform growth of SiO2 particles was achieved within the cross-linked polymer particles (i.e., the polymer particles were filled with the SiO2 particles) simply by utilizing interfacial interactions, including the van der Waals attractive force and hydrogen bonding in nanoscale environments. The structural and morphological features as well as the thermal behaviors of these composites were thoroughly examined by electron microscopes, dynamic light scattering, and thermal analyzers. In particular, the thermal properties of these composites were completely different from the bare polymer, SiO2 particles, and their mixtures, which clearly suggested the successful incorporation of multiple SiO2 particles within the cross-linked polymer particles. Similarly, titanium oxide (TiO2) particles were easily embedded within the polymer particle template which exhibited improved overall properties. As a whole, understanding in situ formation of nanoscale inorganic particles within polymer particle templates can allow for designing novel composite materials possessing enhanced chemical and physical properties.

3.
J Neurooncol ; 127(2): 243-51, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26746691

RESUMO

The purpose of our study was to investigate the therapeutic efficacy of intraarterial (IA) chemotherapy via multiparametric magnetic resonance imaging (MRI) analysis in orthotopic mouse brain tumor models. Stereotactic-guided intracranial inoculation of MDA-MB-231 cells was performed in nude mice. Thirty tumor bearing mice were randomized into three groups, and each group received either IA docetaxel administration (n = 10), intravenous (IV) docetaxel administration (n = 10), or IA solvent injection (n = 10) as control. Treatment response was monitored by diffusion-weighted imaging and dynamic contrast enhanced-MRI obtained 1 day before and 8 days after therapy initiation. Imaging results were correlated with histopathology. In the results, IA chemotherapy showed a significant decrease in tumor volume (86.5 ± 15.6 %) compared to the IV chemotherapy (121.1 ± 39.6%) and control (126.2 ± 22.0%) 8 days after therapy (p < 0.05). Furthermore, IA chemotherapy resulted in a significant increase in mean tumor apparent diffusion coefficient (ADC) values (116.8 ± 44.9%); in contrary IV chemotherapy (66.6 ± 26.9%) and control (69.1 ± 29.5%) showed a significant decrease in ADC values corresponding to further tumor growth (p < 0.05). However, there was no significant difference in perfusion parameters including initial area under the curve, K(trans), K(ep), and V(e) between the groups (p > 0.05). Histopathology confirmed necrosis and necroptosis in the tumors after IA chemotherapy. In conclusion, IA chemotherapy may lead to effective inhibition of tumor cell proliferation and offer potential benefit of inducing higher degree of treatment response than IV chemotherapy.


Assuntos
Neoplasias Encefálicas/secundário , Neoplasias da Mama/patologia , Meios de Contraste , Imagem de Difusão por Ressonância Magnética/métodos , Taxoides/uso terapêutico , Animais , Antineoplásicos/uso terapêutico , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/tratamento farmacológico , Docetaxel , Feminino , Humanos , Técnicas Imunoenzimáticas , Injeções Intra-Arteriais , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Carga Tumoral , Ensaios Antitumorais Modelo de Xenoenxerto
4.
Nanotechnology ; 26(34): 345701, 2015 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-26235352

RESUMO

This study describes a reliable preparation of relatively small Ag/Au-based anisotropic nanostructures possessing tunable absorption bands and their use as surface-enhanced Raman spectroscopy (SERS) substrates. These Au nanostructures were prepared via the seed growth process of small Ag-core-Au-shell-type nanoparticles that were obtained by the subsequent reduction of Ag and Au ions by NaBH(4) and L-ascorbic acid at room temperature. The presence of Ag during the transformation process of the Ag-Au core-shell nanoparticles under light irradiation led to the formation of various small anisotropic Au nanoparticles which clearly exhibited different structural and optical properties from those of nanoparticles prepared from typical Ag-Au alloy or bare Ag or Au seeds. As the optimal size of Au-based substrates for SERS applications was reported to be below 100 nm in diameter under a constant concentration, we tested our moderately small anisotropic nanoparticles (∼55 nm in diameter) as a SERS substrate to examine the signal enhancement of 4-nitrobenzenethiol. These nanoparticles exhibited a greatly increased SERS response compared to those of similar sizes of uniform Ag and Au nanoparticles, presumably because of the increased surface area due to the nanoparticles' anisotropic nature (i.e., chemical effect) and partial overlap of their absorption bands with the SERS excitation wavelength (i.e., electromagnetic effect). In addition, these nanoparticles have shown a suitable stability to prevent significant SERS signal fluctuations caused by unpredictable aggregations. Due to our simple synthetic and modification approaches, relatively small Au-based anisotropic nanostructures can be easily designed to serve as attractive SERS templates.

5.
Neuroradiology ; 57(4): 377-86, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25563632

RESUMO

INTRODUCTION: Ethanol sclerotherapy has shown favorable short-term efficacy in managing head and neck arteriovenous malformation (AVM) which is well known for high recurrence rate after treatment. The purpose of this study was to report immediate treatment results and long-term follow-up results of ethanol sclerotherapy in patients with head and neck AVMs. METHODS: We performed a retrospective review of 45 patients with head and neck AVMs treated between April 1997 and December 2013 by using ethanol sclerotherapy with or without adjunctive surgery. The degree of AVM eradication was analyzed, and complications per treatment session were recorded. Long-term treatment effectiveness was assessed with clinical and imaging follow-up. RESULTS: In total, 132 sclerotherapies were performed in the 45 patients, with a total angiographic eradication rate of 17.8% (n = 8). Partial resolution was achieved in 34 patients, and three patients showed no response. Mean follow-up period was 56.6 months (range, 13-144 months). The long-term recurrence rate was 11.1% (5/45), and all recurrences occurred more than 3 years after the treatment with interval disease-controlled period. The major complication rate was 3.8% (5/132), and 34 minor complications (25.8%) occurred. CONCLUSIONS: Ethanol sclerotherapy is effective for achieving long-term durable cure of head and neck AVMs. In patients with non-curable disease, it is also effective for symptom palliation and long-term disease control. However, given recurrence after interval disease-controlled period, long-term follow-up should be required to detect recurrence in patients with any residual lesion after treatment.


Assuntos
Malformações Arteriovenosas/terapia , Etanol/uso terapêutico , Cabeça , Pescoço , Escleroterapia , Adolescente , Adulto , Angiografia Digital , Angiografia Cerebral , Criança , Pré-Escolar , Feminino , Humanos , Angiografia por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Recidiva , Tomografia Computadorizada por Raios X , Resultado do Tratamento
6.
J Nanosci Nanotechnol ; 14(2): 1563-77, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24749442

RESUMO

Recently, nanoscale metallic particles have been studied extensively due to their tunable and strong optical properties that are well beyond those of organic chromophores. As monometallic nanoparticles have shown strong but narrow absorption bands within the ultraviolet and visible wavelengths, the preparation of bimetallic core-shell structures can give rise to strong, wide, and tunable absorption bands across the visible to near infrared areas. The silver-gold bimetallic nanoparticles with core-shell structures can offer unique physical and optical properties inaccessible to monometallic systems. These nanoparticles have been utilized in many areas of research including chemical catalysis, surface-enhanced Raman spectroscopy, and photothermal therapy. This review article is a comprehensive overview of bimetallic nanoparticle systems consisting of gold and silver; it is based on the recent advances in wet-chemical synthetic methodologies, the characterization of size and shape-dependent optical properties, and various optically driven applications including catalysis, signal-enhancing devices, and biomedical purposes.


Assuntos
Ouro/química , Nanopartículas Metálicas/química , Fotoquimioterapia/instrumentação , Refratometria/instrumentação , Prata/química , Análise Espectral Raman/instrumentação , Ressonância de Plasmônio de Superfície/instrumentação , Cristalização/métodos , Desenho de Equipamento , Análise de Falha de Equipamento , Nanopartículas Metálicas/uso terapêutico , Nanotecnologia/métodos , Tamanho da Partícula
7.
Polymers (Basel) ; 16(2)2024 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-38257014

RESUMO

Tungsten is the most effective eco-friendly material used for radiation shielding in hospitals. However, despite its commendable density and shielding performance, tungsten faces challenges in miscibility with other materials because of its elevated melting point and strength. In this study, to protect medical personnel against scattered rays, which are indirect X-rays, a lightweight material was prepared by mixing graphite oxide material, considering its thinness and flexibility. Tungsten particles were evenly dispersed in the polymer, and nanofibers were prepared using this blended polymer solution via electrospinning. Concurrently, the process technology was explored to craft a thin film sheet and obtain a lead-like shielding effect. A spinning solution was prepared by mixing Fe3O4-rGO (FerGO) and tungsten. At 60 kVp, 0.1 mm was measured as 0.097 mmPb, at 80 kVp, 0.2 mm was measured as 0.196 mmPb, and at 100 kVp, 0.3 mm was measured as 0.279 mmPb, showing similar shielding performance to lead. As density directly affects the shielding effect, graphene oxide played an important role in increasing the density of the material from 1.941 g/cm3 to 2.302 g/cm3. Thus, this study provides an effective process for producing thin film sheets equivalent to lead.

8.
J Nanosci Nanotechnol ; 13(9): 6269-74, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24205643

RESUMO

Polyvinylidene fluoride (PVdF) (Kynar 761) nanofibers were prepared by electrospinning at an external voltage of 6-10 kV, a traveling distance of 7-15 cm and flow rate of 0.4-1 ml/hr. Although the diameter of the fiber was not significantly changed, the electrospinning conditions affected the overall distribution of diameter. This is probably due to the interactions, both attraction and repulsion, of positive charges on polymer solutions and the electrically grounded collector. Especially, the effect of voltage on the distribution of diameter was investigated in this study. The final PVdF nanofiber membrane showed narrow pore-size distribution and high water flux compared with the commercial MF membrane. PVdF nanofiber membranes incorporated nanosilver or graphene oxide were also prepared as nanosilver and graphene have an antibacterial activity. It was found that more than 200 ppm of silver nanoparticles in the PVdF nanofiber had 99.9% of growth inhibition of Staphylococcus aureus and Klebsiella pneumonia. It was also found that 0.2 wt% of graphene oxide in the PVdF electrospinning solution had 99.6% of disinfection property to E-Coli.


Assuntos
Antibacterianos/farmacologia , Grafite/química , Membranas Artificiais , Nanofibras , Óxidos/química , Polivinil/química , Prata/química , Antibacterianos/química , Testes de Sensibilidade Microbiana , Microscopia Eletrônica de Varredura , Staphylococcus aureus/efeitos dos fármacos
9.
Nanotechnology ; 23(27): 275606, 2012 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-22710608

RESUMO

We have developed a very simple approach for preparing physically embedded gold cores in a temperature-responsive hydrogel polymer nanoparticle under fluorescent light irradiation. The complete encapsulation of the multiple gold core nanoparticles is confirmed by the catalytic reduction of 4-nitrophenol, whose reactivity is significantly retarded above the lower critical solution temperature (LSCT) due to the deswelled polymer structure; its increased hydrophobicity slows the access of hydrophilic reactants to the cores. Since these gold cores are physically embedded in the polymer nanoparticles, further growth of the cores is reliably achieved in situ under light irradiation. Interestingly, the resulting composite nanoparticles exhibit reversible solution color changes as well as absorption bands from the visible to near-IR regions below and above the LSCT.


Assuntos
Colorimetria/métodos , Ouro/química , Hidrogéis/química , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Termografia/métodos , Temperatura Alta , Substâncias Macromoleculares/química , Teste de Materiais , Conformação Molecular , Tamanho da Partícula , Refratometria , Propriedades de Superfície
10.
Sci Rep ; 12(1): 22532, 2022 12 29.
Artigo em Inglês | MEDLINE | ID: mdl-36581765

RESUMO

In medical institutions, radiation shielding is an effective strategy to protect medical personnel and patients from exposure. Reducing the weight of the shield worn by medical personnel in the radiation generating area plays a key role in improving their productivity and mobility. In this study, a new lightweight radiation shield was developed by electrospinning a polymer-tungsten composite material to produce nanofibers with a multi-layered thin-film structure similar to that of a morpho butterfly wing. The fabricated shield was in the form of 0.1 mm thick flexible shielding paper. The multi-layer structure of the thin shielding paper was obtained through nanofiber pattern formation via electrospinning a dispersion of tungsten particles. At 0.1 mm thickness, the paper's shielding rate was 64.88% at 60 keV. Furthermore, at 0.3 mm thick and arranged in a laminated structure, the shielding rate was 90.10% and the lead equivalent was 0.296 mmPb. When used as an apron material, the weight can be reduced by 45% compared to existing lead products. In addition, the material is highly processable and can be used to manufacture various flexible products, such as hats, gloves, underwear, and scarves used in medical institutions.


Assuntos
Nanofibras , Proteção Radiológica , Humanos , Tungstênio , Roupa de Proteção , Polímeros
11.
RSC Adv ; 11(2): 678-683, 2020 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-35423702

RESUMO

In this article, polyketone (PK) micro/nano fiber membranes were successfully fabricated by electrospinning and a post treatment process and the membrane characteristics were investigated. The morphology of the fiber membranes showed that ambient humidity during electrospinning changed the roughness of the fiber surface and the addition of NaCl decreased the fiber diameter. In particular, the changes in surface roughness was a very rare and novel discovery. The effect of this discovery on membrane properties was also analyzed. Additionally, the nanofiber membrane was modified by in situ surface reduction. FT-IR spectroscopy indicated the successful reduction modification and water contact angle results proved the improved wetting ability by this modification process. DSC and TGA analysis showed that the micro/nano fiber membranes possessed a high melting point and thermal decomposition temperature. Mechanical tests showed that as fiber membranes, PK micro/nano fiber membranes had relatively high mechanical strength, furthermore the mechanical strength can be easily enhanced by controlling the fiber morphology. From these results, it was concluded that the PK micro/nano fiber membranes could be a promising candidate for many applications such as organic solvent-resistant membranes, high-safety battery separators, oil-water separation, etc.

12.
Polymers (Basel) ; 12(9)2020 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-32899232

RESUMO

Exfoliated graphene oxide (GO) was reliably modified with a cetyltrimethylammonium chloride (CTAC) surfactant to greatly improve the dispersity of the GO in a polyacrylonitrile (PAN) polymer precursor solution. Subsequent electrospinning of the mixture readily resulted in the formation of GO-PAN composite nanofibers containing up to 30 wt % of GO as a filler without notable defects. The absence of common electrospinning problems associated with clogging and phase separation indicated the systematic and uniform integration of the GO within the PAN nanofibers beyond the typical limits. After thoroughly examining the formation and maximum loading efficiency of the modified GO in the PAN nanofibers, the resulting composite nanofibers were thermally treated to form membrane-type sheets. The wettability and pore properties of the composite membranes were notably improved with respect to the pristine PAN nanofiber membrane, possibly due to the reinforcing filler effect. In addition, the more GO loaded into the PAN nanofiber membranes, the higher the removal ability of the methylene blue (MB) and methyl red (MR) dyes in the aqueous system. The adsorption kinetics of a mixed dye solution were also monitored to understand how these MB and MR dyes interact differently with the composite nanofiber membranes. The simple surface modification of the fillers greatly facilitated the integration efficiency and improved the ability to control the overall physical properties of the nanofiber-based membranes, which highly impacted the removal performance of various dyes from water.

13.
Polymers (Basel) ; 12(11)2020 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-33105771

RESUMO

Silver nanoparticle-modified graphene oxide (Ag/GO) was reliably prepared by using sodium borohydride (NaBH4) in the presence of citric acid capping agent via a simple wet chemistry method. This rapidly formed Ag/GO composite exhibited good dispersity in a solution containing hydrophilic polyacrylonitrile (PAN). Subsequent electrospinning of this precursor solution resulted in the successful formation of nanofibers without any notable defects. The Ag/GO-incorporated PAN nanofibers showed thinner fiber strands (544 ± 82 nm) compared to those of GO-PAN (688 ± 177 nm) and bare-PAN (656 ± 59 nm). Subsequent thermal treatment of nanofibers resulted in the preparation of thin membranes to possess the desired pore property and outstanding wettability. The Ag/GO-PAN nanofiber membrane also showed 30% higher water flux value (390 LMH) than that of bare-PAN (300 LMH) for possible microfiltration (MF) application. In addition, the resulting Ag/GO-PAN nanofiber membrane exhibited antibacterial activity against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive). Furthermore, this composite membrane exhibited outstanding anti-fouling property compared to the GO-PAN nanofiber membrane in the wastewater treatment. Therefore, the simple modification strategy allows for the effective formation of Ag/GO composite as a filler that can be reliably incorporated into polymer nanofiber membranes to possess improved overall properties for wastewater treatment applications.

14.
Front Chem ; 8: 834, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33195039

RESUMO

This report describes strategies to increase the reactive surfaces of integrated gold nanoparticles (AuNPs) by employing two different types of host materials that do not possess strong electrostatic and/or covalent interactive forces. These composite particles are then utilized as highly reactive and recyclable quasi-homogeneous catalysts in a C-C bond forming reaction. The use of mesoporous TiO2 and poly(N-isopropylacrylamide), PNIPAM, particles allows for the formation of relatively small and large guest AuNPs and provides the greatly improved stability of the resulting composite particles. As these AuNPs are physically incorporated into the mesoporous TiO2 (i.e., supported AuNPs) and PNIPAM particles (i.e., encapsulated AuNPs), their surfaces are maximized to serve as highly reactive catalytic sites. Given their increased physicochemical properties (e.g., stability, dispersity, and surface area), these composite particles exhibit notably high catalytic activity, selectivity, and recyclability in the homocoupling of phenylboronic acid in water and EtOH. Although the small supported AuNPs display slightly faster reaction rates than the large encapsulated AuNPs, the apparent activation energies (Ea) of both composite particles are comparable, implying no obvious correlation with the size of guest AuNPs under the reaction conditions. Investigating the overall physical properties of various composite particles and their catalytic functions, including the reactivity, selectivity, and Ea, can lead to the development of highly practical quasi-homogeneous catalysts in green reaction conditions.

15.
Neurospine ; 17(1): 288-293, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31614404

RESUMO

OBJECTIVE: Gradually increasing number of minimally invasive spine surgery (MISS), there is an increasing risk of radiation exposure to medical personnel during the surgery. We measured the radiation exposure of the operating room personnel during MISS, tried to find the riskiest person, and checked the effectiveness of a new lead-composite shielding curtain. METHODS: Radiation exposure of medical staffs (operator, first assistant, anesthesiologist, and scrub nurse) involved in MISS procedures of 35 patients without shielding curtain (nonshield group) and 35 patients with shielding curtain (shield group). The shielding curtain had 0.25-mm nominal lead equivalent and was mounted on 2 frame bars fixed on the operating table. RESULTS: In the nonshield group, radiation exposure was significantly higher in the order of operator > first assistant > scrub nurse > anesthesiologist (p < 0.001) during both anteroposterior (AP) and lateral views. In the shield group, the radiation exposure of the operator and the scrub nurse decreased significantly by 94.1% and 76.4% in AP view (p < 0.001), and by 96.3% and 73.9% in lateral view (p < 0.001), respectively. CONCLUSION: Since the radiation dose of the operator was highest in a C-arm-guided MISS, there is a high priority need to protect the operator from the radiation exposure. The shielding curtain could most effectively reduce the radiation exposure of the operator.

16.
Membranes (Basel) ; 9(9)2019 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-31546838

RESUMO

In this study, a series of novel modified graphene oxide (MGO)/polyacrylonitrile (PAN) hybrid nanofiber membranes were fabricated by electrospinning a PAN solution containing up to 1.0 wt.% MGO. The GO was initially prepared by a time-saving improved Hummer's method. Subsequently, the formation of GO was confirmed by scanning electron microscopy (SEM), AFM, Fourier-transform infrared spectroscopy (FT-IR), and Raman spectroscopy. This study also prepared the modified GO with polydiallyldimethylammonium chloride (GP) by using a simple surface post-treatment method to improve its dispersion. Varying amounts of GP were incorporated into PAN nanofibers for the better properties of GP/PAN nanofibers, such as hydrophilicity, mechanical properties, and so on. The resulting GP/PAN hybrid nanofiber membranes were characterized by SEM, FTIR, contact angle, and thermal and mechanical properties. These results showed that the hydrophilic and mechanical properties of GP/PAN hybrid nanofiber membranes were dramatically improved, i.e., 50% improvement for hydrophilicity and 3-4 times higher strength for mechanical property, which indicated the possibility for water treatment application. In addition, the notably improved thermal stability results showed that the hybrid nanofiber membranes could also be a potential candidate for the secondary battery separator.

17.
RSC Adv ; 8(27): 14958-14966, 2018 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-35541340

RESUMO

We describe a new strategy to prepare thermally- and electrochemically-stable polyimide (PI) nanofiber membranes by the hot-press treatment of polyamic acid (PAA) nanofiber sheets in situ and examine their performance as Li-ion battery separators. Typical thermal imidization of PAA to PI membranes using sequential high temperature treatments in an oven takes a long time, but our method readily completes this conversion process at a mild temperature in 30 min while generating a high probability of inter-nanofiber imidization. Along with the improved electrolyte uptake capability and uniform distribution of the pore size and porosity caused by the dense and compact arrangements, the hot-press-induced PI membrane exhibits relatively thin sheets and a much greater mechanical strength than the membrane prepared by the thermal treatment. Subsequently, these PI-based membranes are installed in Li-ion full coin cells as battery separators whose C-rate (charging and discharging) performances are comparable to a commercial polyethylene (PE) separator. In addition, the highly improved thermal stabilities of these PI separators over PE separators are observed during thermal shrinkage and hot-box tests. Overall, our strategy can allow for the manufacture of diverse PI-based membranes with minimal preparation time and cost that can be utilized in high power portable devices requiring thermal and electrochemical stability.

18.
J Neurointerv Surg ; 8(7): 696-701, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26113563

RESUMO

BACKGROUND: Endovascular coil embolization for ophthalmic artery (OphA) aneurysms has the latent risk of occlusion of the OphA during the procedure, which can lead to loss of vision. We report clinical and angiographic results of endovascular treatment of OphA aneurysms together with the efficacy of the balloon occlusion test (BOT). METHODS: From August 2005 to December 2013, 31 consecutive patients with 33 OphA aneurysms were treated in our institution. The patients were classified into two groups according to the location of the OphA within the aneurysmal sac. The BOT was performed in 28 patients using a hypercompliant balloon before endovascular coiling. Collateral circulation between the external carotid artery and the OphA was examined and visual function tests were performed before and after treatment. Patient demographics, angiographic and clinical outcomes were reviewed. RESULTS: Among the 28 patients who underwent the BOT, intact collateral circulation was demonstrated in 26 (92.9%) patients and complete occlusion of the OphA was obtained in three patients after coiling. Retrograde filling of the OphA with choroidoretinal blush was observed on post-procedural angiography and no specific visual symptoms were reported during the follow-up period. Complete embolization was achieved in 30 lesions (96.8%) and only five patients (16.1%) had minor recanalization. CONCLUSIONS: Endovascular treatment of OphA aneurysms can be performed safely and effectively in conjunction with BOT. The BOT may give useful information to predict visual outcome in patients whose OphA is likely to be threatened by the coiling procedure and to determine the optimal treatment strategy.


Assuntos
Oclusão com Balão , Embolização Terapêutica , Aneurisma Intracraniano/diagnóstico por imagem , Aneurisma Intracraniano/terapia , Artéria Oftálmica/diagnóstico por imagem , Testes Visuais , Adulto , Idoso , Oclusão com Balão/métodos , Prótese Vascular , Angiografia Cerebral/métodos , Embolização Terapêutica/métodos , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Prospectivos , Estudos Retrospectivos , Resultado do Tratamento , Testes Visuais/métodos
19.
J Nanosci Nanotechnol ; 15(7): 5035-41, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26373073

RESUMO

A very simple synthetic method is proposed to prepare spiky gold nanoparticles possessing a strong and broad absorption band around the surface of temperature-sensitive poly(N-isopropylacrylamide), poly(NIPAM), particles. The structural properties of the composite particles were thoroughly characterized by UV-visible spectrophotometer, scanning electron microscope, and dynamic light scattering. These composite materials exhibited a reversible swelling and collapsing behavior above and below the lower critical solution temperature. As the surface-adsorbed spiky gold nanoparticles around the poly(NIPAM) possessed a strong and broad absorption band and exhibited the photon-to-heat conversion property, these nanocomposites also showed fast reversible structural diameter changes upon exposure to a broad band light. These types of composite particles may serve as an excellent template for the development of photothermally triggered carrier systems.

20.
ACS Appl Mater Interfaces ; 6(14): 11514-22, 2014 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-24984258

RESUMO

This work describes the light-induced preparation of various gold nanoparticles and demonstrates their possible use as efficient photothermal heating materials and practical heterogeneous catalysts under the irradiation of a solar-based light after being loaded onto a paper-based substrate. The synthesis of gold nanoparticles was accomplished under the irradiation of daily sunlight and a solar-simulated light with an intensity that was closely adjusted to the one-sun condition. Tunable sizes of gold nanoparticles were systematically controlled by the ratio of trisodium citrate and gold chloride ions, particularly with the solar-simulated light source. The size distribution and absorption properties of the resulting nanoparticles were thoroughly characterized by scanning electron microscope, dynamic light scattering, and UV-visible spectroscopy. The broad-band solar-based light sources were found to be efficient external stimuli to induce/enhance the formation of various gold nanoparticles at room temperature. As gold nanoparticles typically exhibit efficient light-induced heating properties due to their strong absorption bands, these nanoparticles were physically embedded on a filter paper to examine their photothermal heating properties and heterogeneous catalytic activity in the reduction of 4-nitrophenol under the irradiation of the solar-simulated light. As expected, the gold-loaded filter papers exhibited a systematic increase of temperature as a function of the gold nanoparticle concentration and enhanced catalytic property under the irradiation of the light, presumably caused by the photothermally induced heating property of the loaded gold nanoparticles. Overall, solar-based light sources can offer dual functions for the synthesis and application of metal nanoparticles possessing strong absorption bands.

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