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1.
Ultramicroscopy ; 210: 112916, 2019 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-31816542

RESUMO

Atomic force microscopy has a tremendous number of applications in a wide variety of fields, particularly in the semiconductor area for the 3D-stacked device. Imaging three-dimensional (3D) structures with blind features has progressively become a critical technique. Recently, a 3D-atomic force microscopy (AFM) technique has been proposed to image 3D features, especially those having sharp apices, like silicon pillars. However, the scanning strategy has drawbacks, such as long scanning time, and unstable operation, based on the premature algorithm. Herein, an improved 3D-AFM algorithm is reported that overcomes the aforementioned problems by an intelligent 3D scanning algorithm that incorporates sidewall history tracking, troubleshooting for sharp sidewall and sticking, and reactive direction adjustment. The proposed algorithm enables the 3D imagery of ZnO nano-rods and silicon nano-pillars to be achieved by using a high aspect-ratio multiwall carbon nanotube-based AFM probe, without time-consuming disorientation. This study establishes a method to construct a 3D image of arbitrary shape in reduced scanning time.

2.
Nanotechnology ; 29(19): 195404, 2018 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-29480165

RESUMO

Reduced equivalent series resistance (ESR) is necessary, particularly at a high current density, for high performance supercapacitors, and the interface resistance between the current collector and electrode material is one of the main components of ESR. In this report, we have optimized chemical vapor deposition-grown graphene (CVD-G) on a current collector (Ni-foil) using reduced graphene oxide as an active electrode material to fabricate an electric double layer capacitor with reduced ESR. The CVD-G was grown at different cooling rates-20 °C min-1, 40 °C min-1 and 100 °C min-1-to determine the optimum conditions. The lowest ESR, 0.38 Ω, was obtained for a cell with a 100 °C min-1 cooling rate, while the sample without a CVD-G interlayer exhibited 0.80 Ω. The CVD-G interlayer-based supercapacitors exhibited fast CD characteristics with high scan rates up to 10 Vs-1 due to low ESR. The specific capacitances deposited with CVD-G were in the range of 145.6 F g-1-213.8 F g-1 at a voltage scan rate of 0.05 V s-1. A quasi-rectangular behavior was observed in the cyclic voltammetry curves, even at very high scan rates of 50 and 100 V s-1, for the cell with optimized CVD-G at higher cooling rates, i.e. 100 °C min-1.

3.
Nanotechnology ; 28(24): 245402, 2017 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-28383286

RESUMO

In this work, the morphology of ZnO nanostructures is engineered to demonstrate enhanced supercapacitor characteristics of ZnO nanocones (NCs) compared to ZnO nanowires (NWs). ZnO NCs are obtained by chemically etching ZnO NWs. Electrochemical characteristics of ZnO NCs and NWs are extensively investigated to demonstrate morphology dependent capacitive performance of one dimensional ZnO nanostructures. Cyclic voltammetry measurements on these two kinds of electrodes in a three-electrode cell confirms that ZnO NCs exhibit a high specific capacitance of 378.5 F g-1 at a scan rate of 20 mV s-1, which is almost twice that of ZnO NWs (191.5 F g-1). The charge-discharge and electrochemical impedance spectroscopy measurements also clearly result in enhanced capacitive performance of NCs as evidenced by higher specific capacitances and lower internal resistance. Asymmetric supercapacitors are fabricated using activated carbon (AC) as the negative electrode and ZnO NWs and NCs as positive electrodes. The ZnO NC⫽AC can deliver a maximum specific capacitance of 126 F g-1 at a current density of 1.33 A g-1 with an energy density of 25.2 W h kg-1 at the power density of 896.44 W kg-1. In contrast, ZnO NW⫽AC displays 63% of the capacitance obtained from the ZnO NC⫽AC supercapacitor. The enhanced performance of NCs is attributed to the higher surface area of ZnO nanostructures after the morphology is altered from NWs to NCs.

4.
Eur J Pharm Biopharm ; 105: 69-74, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27257030

RESUMO

PURPOSE: The purpose of this study was to improve methods of jet injection using a mouse model. We investigated the mechanism of action, efficacy, and safety of the pneumatic device using injection of hyaluronic acid (HA) solution into a mouse model. METHODS: We evaluated the efficacy and safety of an INNOJECTOR™ pneumatic device that pneumatically accelerates a jet of HA solution under high pressure into the dermis of mouse skin. We examined the treatment effects using skin hybrid model jet dispersion experiments, photographic images, microscopy, and histological analyses. RESULTS: Use of the INNOJECTOR™ successfully increased dermal thickness and collagen synthesis in our mouse model. Jet dispersion experiments were performed using agarose gels and a polyacrylamide gel model to understand the dependence of jet penetration on jet power. The mechanisms by which pneumatic injection using HA solution exerts its effects may involve increased dermal thickening, triggering of a wound healing process, and activation of vimentin and collagen synthesis. CONCLUSIONS: Collagen synthesis and increased dermal thickening were successfully achieved in our mouse model using the INNOJECTOR™. Pneumatic injection of HA under high pressure provides a safe and effective method for improving the appearance of mouse skin. Our findings indicate that use of the INNOJECTOR™ may induce efficient collagen remodeling with subsequent marked dermal layer thickening by targeting vimentin.


Assuntos
Ácido Hialurônico/administração & dosagem , Modelos Animais , Agulhas , Pele/efeitos dos fármacos , Animais , Feminino , Camundongos , Camundongos Pelados , Pele/metabolismo , Vimentina/metabolismo
5.
Drug Dev Ind Pharm ; 42(2): 254-62, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26006334

RESUMO

OBJECTIVE: We investigated whether leflunomide can be delivered topically and metabolized into teriflunomide through the skin, and evaluated the therapeutic effect of topical leflunomide. METHODS: Permeation of leflunomide across and formation of its active metabolite within the skin was examined ex vivo. Deposition of teriflunomide in micropig knee joints after applying topical and transdermal patches containing leflunomide was investigated by determining the plasma and joint tissue concentrations. Finally, the anti-inflammatory effects and inhibition of skin sensitization by topical leflunomide were evaluated in a rat adjuvant arthritis model and mice with delayed-type induced hypersensitivity. RESULTS: We found that after topical application of leflunomide on freshly excised mouse, rat and guinea pig skin, ∼24% of the permeated drug existed as teriflunomide. In micropigs treated topically with leflunomide on the knee joint, significantly lower teriflunomide concentrations were found in plasma, but its concentrations in the knee joint were 3.4-fold to 54.6-fold higher than those after oral administration. In a rat arthritis model, the plasma concentration of teriflunomide after treatment with 10% leflunomide topical solution was 7.54-fold lower than that after 10 mg/kg oral leflunomide. However, topical leflunomide was nearly as effective as oral in inhibiting paw edema (37% versus 56%, respectively). The values for hypersensitized mouse ear weight after treatment with topical leflunomide decreased significantly by 26% compared to vehicle. CONCLUSION: These results demonstrate that topically applied leflunomide can be delivered effectively and deposited as teriflunomide in an arthritic joint, possibly allowing better compliance in rheumatoid arthritis patients by avoiding leflunomide's side effects.


Assuntos
Artrite Experimental/tratamento farmacológico , Artrite Reumatoide/tratamento farmacológico , Sistemas de Liberação de Medicamentos , Isoxazóis/administração & dosagem , Administração Cutânea , Animais , Anti-Inflamatórios não Esteroides/administração & dosagem , Anti-Inflamatórios não Esteroides/farmacocinética , Anti-Inflamatórios não Esteroides/farmacologia , Artrite Experimental/patologia , Artrite Reumatoide/patologia , Crotonatos/farmacocinética , Cobaias , Isoxazóis/farmacocinética , Isoxazóis/farmacologia , Leflunomida , Camundongos , Camundongos Pelados , Camundongos Endogâmicos BALB C , Ratos , Ratos Sprague-Dawley , Absorção Cutânea , Suínos , Porco Miniatura , Distribuição Tecidual , Toluidinas/farmacocinética , Adesivo Transdérmico
6.
Int J Pharm ; 480(1-2): 37-47, 2015 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-25595570

RESUMO

We prepared an injectable depot system for the long-term delivery of alendronate using a solid/water/oil/water multiple emulsion technique with poly(lactic-co-glycolic acid) as a carrier. The microparticles were spherical with smooth surfaces, ranging from 20 to 70 µm in size. The microspheres (ALD-HA-RG504H-MC70) were optimally prepared by introducing a viscous material (hyaluronic acid) and a co-solvent system in the inner aqueous and oil phases, respectively, and showed a significantly increased drug encapsulation efficacy (>70%); the initial burst release was <10% after 1 day. In vitro drug release from ALD-HA-RG504H-MC70 followed zero-order kinetics for approximately 4 weeks and the alendronate plasma level was maintained for more than 1 month after intramuscular injection in rabbits. The ovariectomized (OVX) rats with ALD-HA-RG504H-MC70 injected intramuscularly (0.9 mg alendronate/kg/4 weeks) had 112% and 482% increased bone mineral density and trabecular area in the tibia than the OVX controls, respectively, and showed significant improvements in trabecular microarchitecture and bone strength. Furthermore, the major biomarkers of bone turnover revealed that ALD-HA-RG504H-MC70 suppressed effectively the progression of osteoporosis and facilitated new bone formation. Therefore, this sustained release depot system may improve patient compliance and therapeutic efficacy by reducing dose amounts and frequency with minimal adverse reactions.


Assuntos
Alendronato/administração & dosagem , Conservadores da Densidade Óssea/administração & dosagem , Sistemas de Liberação de Medicamentos , Osteoporose/tratamento farmacológico , Alendronato/farmacologia , Animais , Densidade Óssea/efeitos dos fármacos , Conservadores da Densidade Óssea/farmacologia , Química Farmacêutica , Preparações de Ação Retardada , Modelos Animais de Doenças , Emulsões , Feminino , Ácido Hialurônico/química , Injeções Intramusculares , Ácido Láctico/química , Masculino , Microesferas , Osteoporose/patologia , Ovariectomia , Tamanho da Partícula , Ácido Poliglicólico/química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Coelhos , Ratos , Ratos Sprague-Dawley
7.
Lab Anim Res ; 30(2): 79-83, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24999362

RESUMO

Defibrillation is no longer universally recommended as initial intervention for the reversal of ventricular fibrillation (VF) after a prolonged and untreated cardiac arrest. We sought to examine this issue in an animal model where a prolonged untreated VF was induced. The aim of this study was to investigate the potential mechanism of the detrimental effect of defibrillation prior to cardiopulmonary resuscitation (CPR) in prolonged cardiac arrest model. VF was electrically induced in 32 domestic male swine weighing 40±3 kg and remained untreated for 15 minutes. The animals were then randomly allocated to either the initial defibrillation group or the chest compression group. Mean aortic pressure, right atrial pressure and coronary perfusion pressure (CPP) were continuously measured during the performance. The dimensions of the left ventricle (LV) were assessed by echocardiographic methods. The CPP induced by CPR after defibrillation was significantly lower in the initial defibrillation group than in the chest compression group; 1 minute after defibrillation (9±3 mmHg vs. 14.8±7 mmHg (P<0.05)), and after 5 minutes 16±5 mmHg vs. 21.7±1 mmHg (P<0.05). The LV volumes were reduced from 18±2 mmHg to 14±1 mmHg after defibrillation (P<0.05). In brief, this study showed that the conducting defibrillation prior to chest compression may cause a contracture of the LV, resulting in lowering CPP, thus dropping the efficiency of chest compression in a prolonged cardiac arrest model.

8.
J Craniofac Surg ; 24(2): 428-31, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23524708

RESUMO

OBJECTIVES: The objectives of this study were to compare the variations of bone density in the midfacial bones as measured by computed tomography (CT) scans between the osteoporosis and control groups and to evaluate the regions that facial trauma and iatrogenic problem often occur in the midface. METHODS: The 96 patients who underwent both osteomeatal unit CT scans and dual-energy x-ray absorptiometry at our hospital were included in this study retrospectively. Seven skeletal regions were chosen for evaluation: group A (orbital floor, nasal bone), group B (zygomaticomaxillary suture, zygomatic arch, zygomaticofrontal suture), and group C (anterior wall of the maxillary sinus, maxillary process). Forty-seven patients were in the osteoporosis group, and 49 patients were in the control group. On a PACS (picture archiving communication system), the region of interest was analyzed, and the Hounsfield units were measured. RESULTS: There was a significant difference in the mean bone density of the midfacial bones between the osteoporosis group and the control group (P < 0.01). For both groups, each of comparison of the 7 skeletal regions was greater as group A < group B < group C in this order (P < 0.01). CONCLUSIONS: We can see the independent effects of osteoporosis on the midfacial bones using CT scans. Estimated Hounsfield unit through CT scan is able to explain osteoporosis, which may be useful in the clinical fields in the future.


Assuntos
Ossos Faciais/diagnóstico por imagem , Osteoporose/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Absorciometria de Fóton , Densidade Óssea , Ossos Faciais/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Osteoporose/patologia
9.
Clin Exp Otorhinolaryngol ; 5(4): 234-6, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23205230

RESUMO

Meningioma's account for around 15% of all primary brain tumors with some 10% of meningiomas arising in the posterior fossa. In rare cases, a meningioma can form around the endolymphatic sac. When formed in the posterior fossa, meningioma tumors can produce vague, non-specific vertiginous symptoms. Research has observed that a subset of these lesions could produce symptoms indistinguishable from those of Meniere's disease. Therefore, we described the clinical features of a case of posterior petrous meningioma with recurrent vertigo as well as the substantial resolution of symptoms after tumor removal via transmastoid approach.

10.
Biomaterials ; 33(33): 8579-90, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22910220

RESUMO

This study was designed to develop a skin permeable recombinant low-molecular-weight protamine (LMWP) conjugated epidermal growth factor (EGF) (rLMWP-EGF) by linking a highly positive charged LMWP to the N-terminal of EGF through genetic recombination. We evaluated its biological activity, skin permeability, and wound healing efficacy in vivo. The cDNA for rLMWP-EGF was prepared by serial polymerase chain reaction for encoding amino acids of LMWP to the vector for EGF. After expression and purification, recombinant EGF site-specifically conjugated with LMWP was obtained. The in vitro cell proliferation activity was well preserved after LMWP conjugation and was comparable to that of rEGF. rLMWP-EGF showed markedly improved permeability through the three-dimensional artificial human skin constructs, and the cumulative permeation of rLMWP-EGF across the excised mouse skin was about 11 times higher than that of rEGF. Topically applied rLMWP-EGF significantly accelerated the wound closure rate in full thickness as well as a diabetic wound model most probably due to its enhanced skin permeation. These findings demonstrate the therapeutic potential of rLMWP-EGF as a new topical wound healing drug and the site-specific conjugation of LMWP to peptides or proteins by genetic recombination as a useful method for preparing highly effective biomedicines.


Assuntos
Fator de Crescimento Epidérmico/química , Fator de Crescimento Epidérmico/uso terapêutico , Protaminas/química , Pele/efeitos dos fármacos , Pele/patologia , Cicatrização/efeitos dos fármacos , Animais , Humanos , Imuno-Histoquímica , Camundongos
11.
Pharm Res ; 29(7): 2017-29, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22399389

RESUMO

PURPOSE: To evaluate the ability of a novel radiofrequency (RF) microporation technology based on ablation of the skin barrier to enhance topical delivery of active ingredients METHODS: The influence of RF fluence and the molecular size of the absorbent on the permeation enhancement was confirmed by in vitro skin permeation study using Franz diffusion cells. The improved skin rejuvenation effects, such as depigmentation and anti-wrinkle effects, by enhanced topical delivery of α-bisabolol and epidermal growth factor (EGF) through the RF microchannels were investigated in photo-damaged skin. RESULTS: The cumulative amounts of active ingredients through the RF microporated skin were significantly increased. Topically applied α-bisabolol after RF microporation induced rapid onset of skin whitening and significantly increased the ΔL-value of UVB-induced hyperpigmented melanin hairless mouse skin. In addition, wrinkle formation after topical application of EGF with RF microporation was significantly reduced and prevented after 12 weeks, and all parameters involving wrinkles in a replica analysis were similar to those in the negative control. CONCLUSIONS: RF microporation enhances the topical delivery of active ingredients with high molecular weight or of small hydrophilic or lipophilic molecules. Thus, this technology can effectively improve photo-induced hyperpigmentation and wrinkle formation by enhancing topical delivery of active agents.


Assuntos
Sistemas de Liberação de Medicamentos/métodos , Fator de Crescimento Epidérmico/administração & dosagem , Sesquiterpenos/administração & dosagem , Pele/metabolismo , Administração Cutânea , Animais , Fator de Crescimento Epidérmico/farmacocinética , Fator de Crescimento Epidérmico/farmacologia , Camundongos , Camundongos Pelados , Sesquiterpenos Monocíclicos , Ondas de Rádio , Sesquiterpenos/farmacocinética , Sesquiterpenos/farmacologia , Pele/efeitos dos fármacos , Pele/ultraestrutura , Absorção Cutânea , Envelhecimento da Pele/efeitos dos fármacos , Pigmentação da Pele/efeitos dos fármacos
13.
Nanotechnology ; 22(28): 285711, 2011 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-21659688

RESUMO

We report, for the first time, direct observation of enhanced cathodoluminescence (CL) emissions from ZnO nanocones (NCs) compared with ZnO nanowires (NWs). For direct and unambiguous comparison of CL emissions from NWs and nanocones, periodic arrays of ZnO NW were converted to nanocone arrays by our unique HCl [aq] etching technique, enabling us to compare the CL emissions from original NWs and final nanocones at the same location. CL measurements on NW and nanocone arrays reveal that emission intensity of the nanocone at ∼ 387 nm is over two times larger than that of NW arrays. The enhancement of CL emission from nanocones has been confirmed by finite-difference time-domain simulation of enhanced light extraction from ZnO nanocones compared to ZnO NWs. The enhanced CL from nanocones is attributed to its sharp morphology, resulting in more chances of photons to be extracted at the interface between ZnO and air.

15.
Nanotechnology ; 21(9): 095502, 2010 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-20130349

RESUMO

Novel ITO-Si nanowire (NW) metal-insulator-semiconductor (MIS) photodetectors were fabricated by using n-type Si NWs as detection units and ITO films as top gate electrodes. Measurements on the Si NW based device reveal a significant photoresponse, including photocurrent generation with an external quantum efficiency (EQE) of approximately 35% at a peak wavelength of 600 nm at zero external bias, and with an EQE of 70% at a peak wavelength of 800 nm at - 0.5 V bias. The NW device shows a flat and low reflectance and almost constant EQE up to a 60 degrees incident angle of illumination, demonstrating efficient visible-light harvesting by the Si NW antenna.

16.
Int J Pharm ; 385(1-2): 12-9, 2010 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-19833177

RESUMO

A monolithic drug-in-adhesive (MDIA) type patch containing meloxicam (MX) was designed with an acrylic adhesive, a solubility modulator increasing MX solubility, and enhancers. MDIA patches having one adhesive layer between the backing and the release liner give high productivity and improve patient compliance. The biggest problem to prepare MDIA patch including MX was poor solubility of MX. In this research, solubility modulators to increase solubility of MX and acrylic adhesives and skin permeation enhancers were investigated through solubility tests, in vitro skin permeation tests, and stability tests. Consequently, the composition of sodium methoxide (SM), an acrylic adhesive containing poly(vinyl pyrrolidone) blocks (MAS683), polyoxyethylene cetylether (BC-2), and diisopropanolamine (DIPA) made it possible for MX to be contained in an adhesive layer at a concentration of as much as 15 wt% without MX crystal and with high skin permeation over 400 microG/cm(2). Finally, the patch formulation containing MX (MX-patch) selected through our in vitro study was characterized by in vivo using an animal study to acquire pharmacokinetic (PK) parameters and to confirm the anti-inflammatory efficacy of MX-patch. In the animal study, MX-patch was compared with a commercially available piroxicam patch (PX-patch). The amount of MX delivered from MX-patch to the skin surface was believed to be higher than the amount of MX diffused from the skin tissue to circulatory system because the plasma concentration of MX continuously increased up to 32 h, the end time of PK study, although the patch samples were detached at 24 h. PX-patch produced a C(max) at 8 h. MX-patch showed better significant efficacy than PX-patch in adjuvant arthritis model.


Assuntos
Anti-Inflamatórios não Esteroides/administração & dosagem , Tiazinas/administração & dosagem , Tiazóis/administração & dosagem , Resinas Acrílicas/química , Administração Cutânea , Animais , Anti-Inflamatórios não Esteroides/sangue , Anti-Inflamatórios não Esteroides/química , Anti-Inflamatórios não Esteroides/farmacocinética , Artrite Experimental/induzido quimicamente , Artrite Experimental/tratamento farmacológico , Artrite Experimental/microbiologia , Carragenina , Química Farmacêutica , Difusão , Modelos Animais de Doenças , Formas de Dosagem , Composição de Medicamentos , Estabilidade de Medicamentos , Edema/induzido quimicamente , Edema/tratamento farmacológico , Excipientes/química , Adjuvante de Freund , Meloxicam , Camundongos , Camundongos Pelados , Mycobacterium , Osteoartrite/induzido quimicamente , Osteoartrite/tratamento farmacológico , Osteoartrite/microbiologia , Permeabilidade , Piroxicam/administração & dosagem , Povidona/química , Ratos , Ratos Sprague-Dawley , Pele/metabolismo , Absorção Cutânea , Solubilidade , Tecnologia Farmacêutica/métodos , Tiazinas/sangue , Tiazinas/química , Tiazinas/farmacocinética , Tiazóis/sangue , Tiazóis/química , Tiazóis/farmacocinética , Adesivos Teciduais/química
17.
J Nanosci Nanotechnol ; 9(12): 7398-401, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19908796

RESUMO

In this report, a simple wet chemical etching of ZnO nanorods to fabricate large area ZnO nanocones is demonstrated. The cone-like morphology formation utilizes anisotropic etching rate on the different crystal planes of ZnO nanorods in an aqueous solution of HCl (HCl [aq]). To form ZnO nanocones, single crystalline ZnO nanorods with a flat hexagonal shape are synthesized on p-Si(100) using hydrothermal method at 90 degrees C and then, are immersed in HCl [aq]. Electron microscopy reveals that the HCl [aq] treatment of ZnO nanorods significantly etched sidewalls of nanorods, resulting in the cone-like morphology formation. The nanocone formation is the most noticeable when the etching occurred in HCl [aq] with a pH of 2.5-3.0 for 5 min etching time. Geometrical analysis using the electron microscopy reveals that the sidewall of a ZnO nanocone have formed a plane indexed as (0-111) after the etching process.

18.
Nanotechnology ; 20(8): 085609, 2009 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-19417457

RESUMO

Texture-controlled growth of ZnO films on substrates of general materials at room temperature by pulsed laser deposition was demonstrated. The texture of the film changed progressively from (001) to (110) to (100) as the laser fluence increased from 2 J cm(-2) up to 45 J cm(-2). Application of the textured films on Si wafers as seed layers for growing aligned ZnO nanowire arrays (grown along the c-axis) with controlled orientation relative to the substrate surface was demonstrated. The individual nanowire forms an epitaxial orientation relationship with the orientation of the grain that nucleated it; therefore the long axis of the nanowire aligns in conformity with the texture of the seed layer.


Assuntos
Cristalização/métodos , Membranas Artificiais , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Nanotecnologia/métodos , Óxido de Zinco/química , Substâncias Macromoleculares/química , Teste de Materiais , Conformação Molecular , Tamanho da Partícula , Propriedades de Superfície , Temperatura
19.
J Biomed Mater Res A ; 90(2): 446-55, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18546188

RESUMO

Perforated tympanic membranes (TM) and otitis media can be managed with a paper patch or tympanoplasty. However, a paper patch is not biocompatible and tympanoplasty requires complex aseptic surgical procedures. A novel biocompatible patch with a water-insoluble chitosan as the main component was prepared. Optimal mechanical characteristics of a water-insoluble chitosan patch scaffold (CPS) was approximately 40 microm in thickness, 7 MPa in tensile strength, and 107% in percent elongation, even though the characteristics varied significantly depending on the concentrations of chitosan and glycerol. SEM of the CPSs showed a very smooth surface as compared with that of the paper patches. These CPSs showed no cytotoxicity and had a stimulating effect on the proliferation of TM cells in in vitro study. In in vivo study, 4 (21.1%) and 17 (89.5%) TMs out of 19 adult rats with CPSs showed no perforations at 1 and 2 weeks, respectively. However, left control TMs showed healing of 0 (0%) at 1 week and 18 (94.7%) at 2 weeks. TEM findings of regenerated eardrums using CPSs showed thinner, smoother, and more compact tissues than spontaneously healed eardrums. A CPS was more effective than spontaneous healing to repair traumatic TM perforations.


Assuntos
Materiais Biocompatíveis/química , Quitosana/química , Perfuração da Membrana Timpânica/cirurgia , Água/química , Animais , Proliferação de Células , Teste de Materiais , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão/métodos , Otite Média/cirurgia , Ratos , Estresse Mecânico , Resistência à Tração , Membrana Timpânica/patologia , Cicatrização
20.
Nanotechnology ; 19(43): 435302, 2008 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-21832689

RESUMO

A simple, scalable, and cost-effective technique for controlling the growth density of ZnO nanorod arrays based on a layer-by-layer polyelectrolyte polymer film is demonstrated. The ZnO nanorods were synthesized using a low temperature (T = 90 °C), solution-based method. The density-control technique utilizes a polymer thin film pre-coated on the substrate to control the mass transport of the reactant to the substrate. The density-controlled arrays were investigated as potential field emission candidates. The field emission results revealed that an emitter density of 7 nanorods µm(-2) and a tapered nanorod morphology generated a high field enhancement factor of 5884. This novel technique shows promise for applications in flat panel display technology.

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