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1.
Nanotechnology ; 31(25): 255702, 2020 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-32143199

RESUMO

We prepared ZnO nanocomposites with WO3 or CuO nanostructures to improve the photocatalytic performance of ZnO nanostructures. Characterization of the nanocomposites using scanning electron microscopy, x-ray diffraction, UV-vis spectrometry and photoluminescence revealed the morphologies and wide light absorption range of the materials. The highest current densities of WO3/ZnO and CuO/ZnO nanocomposites were 1.28 mA cm-2 and 2.49 mA cm-2 at 1.23 V (versus a reversible hydrogen electrode) under AM 1.5 100 mW cm-2, which are ~1.2- and 3.5-fold greater than those of bare ZnO nanostructures, respectively. The easy fabrication process suggests that nanocomposites with narrow bandgap materials, such as WO3 and CuO, will improve the performance of electrochemical and optoelectrical devices such as dye-sensitized solar cells and biosensors.

2.
Clin Orthop Surg ; 11(3): 265-269, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31475045

RESUMO

BACKGROUND: Hip fracture surgery (HFS) is often associated with perioperative blood loss, and it frequently necessitates transfusion. However, the hemoglobin (Hb) threshold for transfusion remains controversial in hip fracture patients. We evaluated the usefulness of the restrictive strategy and preoperative intravenous iron supplementation in HFS. METHODS: We retrospectively reviewed the medical records of 1,634 patients (> 60 years of age) who underwent HFS between May 2003 and June 2014 and were followed up for 1 year or more after surgery. We used the liberal transfusion strategy until May 2009 to determine the transfusion threshold; afterwards, we switched to the restrictive transfusion strategy. Patients with the restrictive transfusion strategy (restrictive group) received intravenous iron supplementation before surgery. We compared the transfusion rate, morbidity, and mortality of the restrictive group with those of the patients with the liberal transfusion strategy (liberal group). RESULTS: Preoperative intravenous iron supplementation was not associated with any adverse reactions. The transfusion rate was 65.3% (506/775) in the liberal group and 48.2% (414/859) in the restrictive group (p < 0.001). The mean hospital stay was shorter in the restrictive group (21.5 vs. 28.8 days, p < 0.001). There was no significant difference in the postoperative medical complications including myocardial infarction and cerebrovascular event. Mortality at postoperative 30, 60, and 90 days was similar between the two groups. CONCLUSIONS: Our blood management protocol involving restrictive strategy combined with preoperative intravenous iron supplementation appears to be effective and safe in HFS of elderly patients.


Assuntos
Anemia/terapia , Transfusão de Sangue/normas , Fraturas do Quadril/cirurgia , Compostos de Ferro/administração & dosagem , Administração Intravenosa , Idoso , Idoso de 80 Anos ou mais , Anemia/etiologia , Perda Sanguínea Cirúrgica , Suplementos Nutricionais , Feminino , Hemoglobinas/análise , Fraturas do Quadril/sangue , Humanos , Masculino , Procedimentos Ortopédicos , Hemorragia Pós-Operatória/terapia , Cuidados Pré-Operatórios , Estudos Retrospectivos
3.
J Bone Metab ; 25(4): 219-226, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30574466

RESUMO

BACKGROUND: Although studies and interest in sarcopenia have increased, it is still a matter of debate which muscle mass index better represents the aging process. We compared 3 indices for muscle mass (appendicular skeletal muscle mass [ASM]/weight, ASM/height2, and the body mass index [BMI]-adjusted muscle mass index [ASM/BMI]) to determine which better reflected the aging process in terms of the decline in bone mineral density (BMD), visual acuity (VA), hearing power, renal function, pulmonary function, and handgrip strength. METHODS: We performed a retrospective cross-sectional study using the Korea National Health and Nutrition Examination Survey in the Korean population. Between 2008 and 2011, a total of 14,415 men and 17,971 women aged 10 years or older participated in the study. We plotted the changes in the 3 indices of muscle mass and compared these with changes in BMD, VA, hearing power, renal function, pulmonary function, and handgrip strength according to each age group. RESULTS: The ASM/BMI showed similar changes in terms of surrogate markers of the aging process, while the ASM/weight and ASM/height2 showed no correlation. CONCLUSIONS: Among muscle indices for sarcopenia, only the ASM/BMI represented the aging process.

4.
J Clin Monit Comput ; 32(1): 33-43, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28188408

RESUMO

We compared the similarity of cardiac-output (CO) estimates between available bolus thermodilution pulmonary-artery catheters (PAC), arterial pulse-contour analysis (LiDCOplus™, FloTrac™ and PiCCOplus™), and bioreactance (NICOM™). Repetitive simultaneous estimates of CO obtained from the above devices were compared in 21 cardiac-surgery patients during the first 2 h post-surgery. Mean and absolute values for CO across the devices were compared by ANOVA, Bland-Altman, Pearson moment, and linear-regression analyses. Twenty-one simultaneous CO measurements were made before and after therapeutic interventions. Mean PAC CO (5.7 ± 1.5 L min) was similar to LiDCO™, FloTrac™, PiCCO™, and NICOM™ CO (6.0 ± 1.9, 5.9 ± 1.0, 5.7 ± 1.8, 5.3 ± 1.0 L min, respectively). Mean CO bias between each paired method was -0.10 (PAC-LiDCO), 0.18 (PAC-PiCCO), -0.40 (PAC-FloTrac), -0.71 (PAC-NICOM), 0.28 (LiDCO-PiCCO), 0.39 (LiDCO-FloTrac), -0.97 (NICOM-LiDCO), 0.61 (PiCCO-FloTrac), -1.0 (NICOM-FloTrac), -0.73 (NICOM-PiCCO) L/min, with limits of agreement (1.96 SD, ±95% CI) of ± 2.01, ±2.35, ±2.27, ±2.70, ±1.97, ±2.17, ±3.51, ±2.87, ±2.40, and ± 3.14 L min, respectively, and the percentage error for each of the paired devices was 35, 41, 40, 47, 33, 36, 59, 50, 42, and 55%, respectively. From Pearson moment analysis, dynamic changes in CO, estimated by each device, showed good cross-correlations. Although all devices studied recorded similar mean CO values, which dynamically changed in similar directions, they have markedly different bias and precision values relative to each other. Thus, results from prior studies that have used one device to estimate CO cannot be used to validate others devices.


Assuntos
Débito Cardíaco , Procedimentos Cirúrgicos Cardíacos/instrumentação , Cateterismo de Swan-Ganz/instrumentação , Cateterismo de Swan-Ganz/métodos , Frequência Cardíaca , Artéria Pulmonar , Termodiluição/métodos , Idoso , Algoritmos , Análise de Variância , Feminino , Humanos , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Monitorização Fisiológica , Período Pós-Operatório , Reprodutibilidade dos Testes , Fatores de Tempo
5.
Arthroscopy ; 34(2): 530-535, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29183645

RESUMO

PURPOSE: This study investigated the clinical outcomes and mid- to long-term survival rates in patients undergoing transtibial pullout repair of medial meniscus posterior root tears (MMPRTs) after a minimum follow-up of 5 years. METHODS: Between 2005 and 2011, patients with MMPRTs who had been followed for at least 5 years after undergoing transtibial pullout repair were recruited. Participants were identified using medical records and information in a prospectively collected database. Clinical outcomes were assessed based on a comparison of patient preoperative Lysholm scores and their scores at the final follow-up. A Kaplan-Meier survival analysis was used to investigate the survival rates of repair procedures. Clinical failures were defined as cases requiring conversion to total knee arthroplasty (TKA) or having final Lysholm score <65 or less than their preoperative scores. RESULTS: Overall, 91 patients (mean age, 58.7 ± 9.7 years) were included: the mean follow-up duration was 84.8 ± 13.8 months. Among these patients, the mean Lysholm score improved significantly from 51.8 ± 7.9 preoperatively to 83.0 ± 11.1 at the final follow-up (P < .001). Overall, 4 patients failed due to conversion to TKA (n = 1) or having final Lysholm scores <65 or less than the preoperative scores (n = 3). The overall Kaplan-Meier probabilities of survival after repair were 99% at 5 years, 98% at 6 years, 95% at 7 years, and 92% at 8 years. CONCLUSIONS: Among patients with MMPRTs, transtibial pullout repair demonstrated a high clinical survival rate and the patients demonstrated clinical improvement, based on mid- and long-term follow-up examinations. LEVEL OF EVIDENCE: Level IV, retrospective uncontrolled case series.


Assuntos
Artroscopia/métodos , Previsões , Meniscos Tibiais/cirurgia , Sobrevivência , Lesões do Menisco Tibial/cirurgia , Feminino , Seguimentos , Humanos , Estimativa de Kaplan-Meier , Imageamento por Ressonância Magnética , Masculino , Meniscos Tibiais/diagnóstico por imagem , Pessoa de Meia-Idade , República da Coreia/epidemiologia , Estudos Retrospectivos , Taxa de Sobrevida/tendências , Lesões do Menisco Tibial/diagnóstico , Lesões do Menisco Tibial/mortalidade
6.
Nanomaterials (Basel) ; 7(2)2017 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-28336868

RESUMO

Nanoprobes with multimodal functionality have attracted significant interest recently because of their potential applications in nanomedicine. This paper reports the successful development of lanthanide-doped Y2O3 nanoprobes for potential applications in optical and magnetic resonance (MR) imaging. The morphology, structural, and optical properties of these nanoprobes were characterized by transmission electron microscope (TEM), field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), energy-dispersive X-ray (EDX), and photoluminescence (PL). The cytotoxicity test showed that the prepared lanthanide-doped Y2O3 nanoprobes have good biocompatibility. The obvious contrast enhancement in the T1-weighted MR images suggested that these nanoprobes can be used as a positive contrast agent in MRI. In addition, the clear fluorescence images of the L-929 cells incubated with the nanoprobes highlight their potential for optical imaging. Overall, these results suggest that prepared lanthanide-doped Y2O3 nanoprobes can be used for simultaneous optical and MR imaging.

7.
Acta Paediatr ; 105(10): 1152-7, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27634684

RESUMO

UNLABELLED: Two of the most prevalent problems children facing worldwide are injuries and obesity. We conducted a systematic review of published studies that evaluated the effects of obesity on children with traumatic injuries. Six studies published between 2006 and 2014 were identified, comprising a total of 4594 children: 867 were obese and 3727 were not. Obese children were 25% more likely to have extremity fractures than nonobese children (p = 0.003), and their mortality rate was significantly higher at 4.7% versus 2.8% (p = 0.026). CONCLUSION: Our review showed that obese children were more likely to have extremity fractures and die of traumatic injuries than nonobese children.


Assuntos
Fraturas Ósseas/etiologia , Obesidade Infantil/complicações , Criança , Humanos , Ferimentos e Lesões/mortalidade
8.
J Nanosci Nanotechnol ; 16(5): 4864-9, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-27483836

RESUMO

We describe a highly durable Ti-mesh based triboelectric nanogenerator (Ti-TENG) with a sandwich structure that harvests electrical energy from contact electrification. The electrical output from the fabricated Ti-TENG by compressing and releasing strain was measured under different applied loads and frequencies. The Ti-TENG generated a peak voltage and current up to -1.1 V and -14 nA at an applied force of 30 N and frequency of 1.1 Hz. Obtained potentials were used to charge a capacitor and power a commercially available light emitting diode (LED). In particular, the Ti-TENG, which exhibited high electrical stability, can be used in applications requiring high levels of robustness and durability. For example, the Ti-TENG was applied as step counter while walking and running, demonstrating its capability to self-power devices. We believe that the device provides a highly promising, robust and durable platform for self-powered applications that effectively harnesses energy from mechanical movements.

9.
J Cardiothorac Vasc Anesth ; 30(3): 709-15, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27321793

RESUMO

OBJECTIVE: To define the differential effect of site-specific ventricular counterpacing efficacy during cardiac resynchronization therapy (CRT) to identify the most informative imaging views to quantify it. Cross-sectional and long-axis views commonly are used to assess left ventricular (LV) contractility. DESIGN: The effects of LV apical (LVa) and free-wall (LVfw) pacing during CRT on long- and short-axis contraction, cardiac output, and stroke work were assessed in an open-chested acute canine model to determine whether LVa and LVfw would induce earlier apical than basilar LV radial contraction and earlier free-wall than septal contraction, respectively. Apical (CRTa) and free-wall (CRTfw) using right ventricular (RV) pacing-induced dyssynchrony also were examined. SETTING: University large animal research laboratory. PARTICIPANTS: Ten acutely anesthetized and instrumented open-chested purpose-bred dogs. INTERVENTIONS: RV pacing served as the model of cardiac dyssynchrony. Selective LVfw and LVa pacing alone or with RV (CRTfw and CRTa, respectively) were studied relative to right atrial pacing (RA) as the control. MEASUREMENTS AND MAIN RESULTS: Two pairs of 3 ultrasonic crystals were place along the LV longitudinal axis-apex and mid-to-base pairs along septal and free wall lines. Conductance catheter-defined longitudinal LV segmental volumes and pressure-volume data were collected. RV decreased cardiac output and stroke work compared with RA (2.0±0.3 v 1.4±0.1 L/min; 137±22 v 60±14 mJ; p<0.05, respectively). LVfw but not LVa decreased stroke work (130±35 mJ), and CRTa but not CRTfw improved both (2.1±0.2 L/min; 113±13 mJ; p<0.01 v RV pacing). No difference in time to minimal length free wall-to-septal crystal was seen with pacing. Both LVa and CRTa displayed increased apical-to-basilar shortening delay compared with RA, RV, and LVfw (42±47, 9±105, and 1±46 msec, respectively; p<0.05). No matching regional LV volume changes were seen during LVa. CONCLUSIONS: LV functional analysis from only a cross-sectional plane may be insufficient to characterize improved LV contraction synchrony during multisite CRT.


Assuntos
Estimulação Cardíaca Artificial , Contração Miocárdica , Função Ventricular Esquerda , Animais , Débito Cardíaco , Terapia de Ressincronização Cardíaca , Cães
10.
Luminescence ; 31(3): 654-9, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-27037967

RESUMO

The binding of ZnO nanoparticles (NPs) and caffeic acid (CFA) was investigated using fluorescence quenching, UV/vis absorption spectrscopy, Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) and dynamic light scattering (DLS) at different temperatures. The study results indicated fluorescence quenching between ZnO NPs and CFA rationalized in terms of a static quenching mechanism or the formation of non-fluorescent CFA-ZnO. From fluorescence quenching spectral analysis, the binding constant (K(a)), number of binding sites (n) and thermodynamic properties were determined. Values of the quenching (K(SV)) and binding (K(a)) constants decrease with increasing temperature and the number of binding sites n = 2. The thermodynamic parameters determined using Van't Hoff equation indicated that binding occurs spontaneously involving the hydrogen bond, and van der Waal's forces played a major role in the reaction of ZnO NPs with CFA. The FTIR, TEM and DLS measurements also indicated differences in the structure, morphology and size of CFA, ZnO NPs and their corresponding CFA-ZnO.


Assuntos
Ácidos Cafeicos/química , Nanopartículas/química , Óxido de Zinco/química , Sítios de Ligação , Fluorescência , Termodinâmica
11.
Luminescence ; 31(2): 565-572, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26934864

RESUMO

The interactions of caffeine (CF) with chlorogenic acid (CGA) and caffeic acid (CFA) were investigated by fluorescence quenching, UV/vis and Fourier transform infrared (FTIR) spectroscopic techniques. The results of the study indicated that the fluorescence quenching between caffeine and hydroxycinnamic acids could be rationalized in terms of static quenching or the formation of non-fluorescent CF-CFA and CF-CGA complexes. From fluorescence quenching spectral analysis, the quenching constant (KSV), quenching rate constant (kq), number of binding sites (n), thermodynamic properties and conformational changes of the interaction were determined. The quenching constants (KSV) between CF and CGA, CFA are 1.84 × 10(4) and 1.04 × 10(4) L/mol at 298 K and their binding site n is ~ 1. Thermodynamic parameters determined using the Van't Hoff equation indicated that hydrogen bonds and van der Waal's forces have a major role in the reaction of caffeine with caffeic acid and chlorogenic acid. The 3D fluorescence, UV/vis and FTIR spectra also showed that the binding of CF with CFA and CGA induces conformational changes in CFA and CGA.


Assuntos
Ácidos Cafeicos/química , Cafeína/química , Ácido Clorogênico/química , Fluorescência , Sítios de Ligação , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier
12.
J Vis Exp ; (107): e53491, 2016 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-26863044

RESUMO

Well-aligned ZnO nanostructures have been intensively studied over the last decade for remarkable physical properties and enormous applications. Here, we describe a one-step fabrication technique to synthesis freestanding ZnO nanorod/graphene/ZnO nanorod double heterostructure. The preparation of the double heterostructure is performed by using thermal chemical vapor deposition (CVD) and preheating hydrothermal technique. In addition, the morphological properties were characterized by using the scanning electron microscopy (SEM). The utility of freestanding double heterostructure is demonstrated by fabricating the piezoelectric nanogenerator. The electrical output is improved up to 200% compared to that of a single heterostructure owing to the coupling effect of the piezoelectricity between the arrays of ZnO nanorods on the top and bottom of graphene. This unique double heterostructure have a tremendous potential for applications of electrical and optoelectrical devices where the high number density and specific surface area of nanorod are needed, such as pressure sensor, immuno-biosensor and dye-sensitized solar cells.


Assuntos
Eletricidade , Grafite/química , Nanotubos/química , Óxido de Zinco/química
13.
Sci Rep ; 6: 21986, 2016 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-26906215

RESUMO

Increased survival of cancer cells mediated by high levels of ionizing radiation (IR) reduces the effectiveness of radiation therapy for non-small cell lung cancer (NSCLC). In the present study, danshensu which is a selected component of traditional oriental medicine (TOM) compound was found to reduce the radioresistance of NSCLC by inhibiting the nuclear factor-κB (NF-κB) pathway. Of the various TOM compounds reported to inhibit the IR activation of NF-κB, danshensu was chosen as a final candidate based on the results of structural comparisons with human metabolites and monoamine oxidase B (MAOB) was identified as the putative target enzyme. Danshensu decreased the activation of NF-κB by inhibiting MAOB activity in A549 and NCI-H1299 NSCLC cells. Moreover, it suppressed IR-induced epithelial-to-mesenchymal transition, expressions of NF-κB-regulated prosurvival and proinflammatory genes, and in vivo radioresistance of mouse xenograft models. Taken together, this study shows that danshensu significantly reduces MAOB activity and attenuates NF-κB signaling to elicit the radiosensitization of NSCLC.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Carcinoma Pulmonar de Células não Pequenas/terapia , Lactatos/farmacologia , Neoplasias Pulmonares/terapia , Inibidores da Monoaminoxidase/farmacologia , Monoaminoxidase/genética , Tolerância a Radiação/efeitos dos fármacos , Animais , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Linhagem Celular Tumoral , Medicamentos de Ervas Chinesas , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Transição Epitelial-Mesenquimal/efeitos da radiação , Raios gama/uso terapêutico , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Medicina Tradicional do Leste Asiático , Camundongos , Camundongos Nus , Monoaminoxidase/metabolismo , NF-kappa B/genética , NF-kappa B/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
14.
Luminescence ; 31(1): 118-26, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25991491

RESUMO

The effects of solvent polarity on absorption and fluorescence spectra of biologically active compounds (chlorogenic acid (CGA) and caffeic acids (CA)) have been investigated. In both spectra pronounced solvatochromic effects were observed with shift of emission peaks larger than the corresponding UV-vis electronic absorption spectra. From solvatochromic theory the ground and excited-state dipole moments were determined experimentally and theoretically. The differences between the excited and ground state dipole moment determined by Bakhshiev, Kawski-Chamma-Viallet and Reichardt equations are quite similar. The ground and excited-state dipole moments were determined by theoretical quantum chemical calculation using density function theory (DFT) method (Gaussian 09) and were also similar to the experimental results. The HOMO-LUMO energy band gaps for CGA and CFA were calculated and found to be 4.1119 and 1.8732 eV respectively. The results also indicated the CGA molecule is more stable than that of CFA. It was also observed that in both compounds the excited state possesses a higher dipole moment than that of the ground state. This confirms that the excited state of the hydroxycinnamic compounds is more polarized than that of the ground state and therefore is more sensitive to the solvent.


Assuntos
Ácidos Cafeicos/química , Ácido Clorogênico/química , Solventes/química , Estrutura Molecular , Teoria Quântica , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta
15.
BMC Musculoskelet Disord ; 16: 395, 2015 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-26704907

RESUMO

BACKGROUND: Isolated fractures of the greater trochanter (GT) of the femur are uncommon and few studies have assessed the diagnosis and appropriate therapeutic schedule for these fractures. The current data regarding assessment of isolated fractures of the GT are limited to a few reviews based on the experience of a single institution. Therefore, we asked the following questions: (1) what proportion of cases has an associated extension of the fracture into the intertrochanteric region in isolated GT fracture and (2) what are the treatment options and outcomes of GT fractures with occult intertrochanteric fractures. METHODS: We conducted a systematic review of published studies that evaluated patients who displayed isolated GT fracture on routine radiographic examination and underwent a magnetic resonance imaging (MRI) scan because of the suspicion of extension into the intertrochanteric region. A structured literature review of multiple databases (PubMed, EMBASE, CINAHL, and Cochrane systematic reviews) referenced articles from 1950 to 2015. RESULTS: A total of 110 patients were identified from 7 published studies. MRI documented isolated GT fractures diagnosed on initial radiographs in only 11 of 110 patients (10%). In 99 patients (90%), MRI examinations revealed extension of the fracture into the intertrochanteric region. Surgical fixation was necessary for 61 patients, with a pooled percentage of 55%. No complications were observed after surgery. CONCLUSIONS: Our study has helped to elucidate further the assessment of isolated fracture of the GT. We believe that MRI is a reasonable option for patients presenting with isolated GT fracture on plain radiographs.


Assuntos
Fraturas do Quadril/patologia , Imageamento por Ressonância Magnética , Fixação Interna de Fraturas , Fraturas do Quadril/diagnóstico por imagem , Fraturas do Quadril/cirurgia , Humanos , Radiografia , Resultado do Tratamento
16.
Nanotechnology ; 24(34): 345603, 2013 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-23900135

RESUMO

Multifunctional mesoporous silica nanocomposites are attractive carriers for targeted drug delivery in nanomedicine. Although promising developments have been made in the fabrication of multifunctional mesoporous silica nanocomposites, the design and mass production of novel multifunctional carriers are still challenging. This paper reports the facile one-pot fabrication of a multifunctional inorganic composite composed of superparamagnetic Fe3O4 nanoparticles and coated dye-functionalized mesoporous silica with a high specific surface area. The resulting composite particles had a tunable particle size, special open pore channels with high specific surface area, which is quite favorable for drug loading and release properties, as well as luminescent and superparamagnetic properties suitable for targeted drug delivery and tracking. This composite exhibited low toxicity, suggesting potential biomedical applications.


Assuntos
Tecnologia Biomédica/métodos , Nanofibras/química , Dióxido de Silício/química , Animais , Morte Celular/efeitos dos fármacos , Endocitose/efeitos dos fármacos , Compostos Férricos/química , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Fenômenos Magnéticos , Camundongos , Microscopia de Fluorescência , Nanofibras/toxicidade , Nanofibras/ultraestrutura , Tamanho da Partícula , Porosidade , Dióxido de Silício/toxicidade , Espectrometria de Fluorescência
17.
Nanoscale Res Lett ; 8(1): 357, 2013 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-23962025

RESUMO

Bifunctional monodispersed Fe3O4 particles coated with an ultrathin Y2O3:Tb3+ shell layer were fabricated using a facile urea-based homogeneous precipitation method. The obtained composite particles were characterized by powder X-ray diffraction, transmission electron microscopy (TEM), quantum design vibrating sample magnetometry, and photoluminescence (PL) spectroscopy. TEM revealed uniform spherical core-shell-structured composites ranging in size from 306 to 330 nm with a shell thickness of approximately 25 nm. PL spectroscopy confirmed that the synthesized composites displayed a strong eye-visible green light emission. Magnetic measurements indicated that the composite particles obtained also exhibited strong superparamagnetic behavior at room temperature. Therefore, the inner Fe3O4 core and outer Y2O3:Tb3+ shell layer endow the composites with both robust magnetic properties and strong eye-visible luminescent properties. These composite materials have potential use in magnetic targeting and bioseparation, simultaneously coupled with luminescent imaging.

18.
Pacing Clin Electrophysiol ; 36(1): 13-23, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22897587

RESUMO

BACKGROUND: Quantification of global ventricular rotational deformation, expressed as twist or torsion, and its dynamic changes is important in understanding the pathophysiology of heart disease and its therapy. Various techniques, such as sonomicrometry, allow tracking of specific sites within the myocardium. Quantification of twist from such data requires a longitudinal reference axis of rotation. Current methods require specific positioning and numbers of myocardial markers and assumptions about temporal positional evolution that may be violated during dyssynchronous contraction. METHODS: We present a new method to assess myocardial twist that makes minimal fully explicit assumptions while removing extraneous assumptions, by performing a least squares orthogonal distance regression of all position data on an ellipsoidal ventricular model. Rotational deformation is quantified in terms of the ellipsoid's internal coordinate system, allowing intuitive visualization. RESULTS: We tested this method on a set of sparse, noisy sonomicrometric crystal data in dogs under different pacing regimes to model dyssynchrony and cardiac resynchronization. We found that this method yielded robust and plausible data. This technique is also fully automated while identifying when data may be insufficient for reliable quantification of rotational deformation. CONCLUSION: This approach may allow future analysis of myocardial contraction with less tracking sites and relaxed positioning requirements while identifying situations where data are insufficient for reliable quantification of rotational deformation.


Assuntos
Estimulação Cardíaca Artificial/métodos , Diagnóstico por Computador/métodos , Técnicas de Imagem por Elasticidade/métodos , Anormalidade Torcional/diagnóstico , Anormalidade Torcional/fisiopatologia , Disfunção Ventricular Esquerda/diagnóstico , Disfunção Ventricular Esquerda/fisiopatologia , Animais , Interpretação Estatística de Dados , Cães , Técnicas de Imagem por Elasticidade/instrumentação , Análise de Regressão , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
19.
Nanoscale Res Lett ; 7(1): 556, 2012 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-23043645

RESUMO

Rare-earth phosphors are commonly used in display panels, security printing, and fluorescent lamps, and have potential applications in lasers and bioimaging. In the present study, Eu3+- and Dy3+-codoped uniform-shaped Y2O3 submicron particles were prepared using the urea homogeneous precipitation method. The structure and morphology of the resulting particles were characterized by X-ray diffraction, field emission scanning electron microscope, and field emission transmission electron microscope, whereas their optical properties were monitored by photoluminescence spectroscopy. The room-temperature luminescence color emission of the synthesized particles can be tuned from red to yellow by switching the excitation wavelength from 254 to 350 nm. The luminescence intensities of red and yellow emissions could be altered by varying the dopant concentration. Strong quenching was observed at high Eu3+ and Dy3+ concentrations in the Y2O3 host lattice.

20.
J Nanosci Nanotechnol ; 12(7): 5847-51, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22966668

RESUMO

Nanosized particles with different Ho3+ concentrations were synthesized in LaAlO3 lattices using a simple Pechini-type sol-gel method. X-ray diffraction measurements were used to investigate the structural composition and the effects of holmium dopant concentration on LaAlO3:Ho3+ crystal formation. Field-emission scanning-electron microscopy images confirm the formation of approximately spherical particles with an average size about 100 nm. The photoluminescence results yielded optimal holmium ion concentration in LaAlO3 host matrices was about 3% in mol equivalent. The mechanism that are responsible for the photoluminescence emission processes discussed with the help of Ho3+-ion Dieke energy level diagram. Power dependent slope measurements were performed to identify up-conversion photoluminescence process involved in LaAlO3:Ho3+.

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