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This study aimed to evaluate the bioactivities and biocompatibilities of porous polylactic acid (PLA) reinforced with cellulose nanofiber (CNF) scaffolds. The in vitro degradation behaviors of the porous PLA/CNF scaffolds were systematically measured for up to 8 weeks in a phosphate-buffered saline medium at 37 °C. The reinforcement of CNF resisted the biodegradation of the scaffolds. The in vitro cytotoxicity and biocompatibility of the scaffolds were determined using the Beas2B American Type Culture Collection cells. The 3-(4,5-cimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide cytotoxicity and proliferation tests showed that the scaffolds were non-toxic, and epithelial cells grew well on the scaffold after 7 days of culture, whereas the percentage of cell proliferation on the PLA/CNF15 scaffold was the largest, 130 %. A scratch wound-healing assay was performed to evaluate the suitability of the scaffolds for cell migration. The results demonstrated that the scaffolds exhibited good cell migration towards nearly complete wound closure.
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Celulosa , Nanofibras , Andamios del Tejido , PoliésteresRESUMEN
A packaging material that is environment-friendly with excellent mechanical and physicochemical properties, biodegradable and ultraviolet (UV) protection and thermal stability was prepared to reduce plastic waste. Six different concentrations of Pennisetum purpureum/Napier cellulose nanowhiskers (NWCs) (i.e. 0, 0.5, 1.0, 1.5, 2.0, and 3.0 wt%) were used to reinforce polylactic acid (PLA) by a solvent casting method. The resulting bionanocomposite film samples were characterised in terms of their morphology, chemical structure, crystallinity, thermal degradation and stability, light transmittance, water absorption, biodegradability, and physical and mechanical properties. Field-emission scanning electron microscopy showed the excellent dispersion of NWC in the PLA matrix occurred with NWC concentrations of 0.5-1.5 wt%. All the bionanocomposite film samples exhibited good thermal stability at approximately 343-359 °C. The highest water absorption was 1.94%. The lowest transparency at λ800 was 16.16% for the PLA/3.0% NWC bionanocomposite film, which also has the lowest UVA and UVB transmittance of 7.49% and 4.02%, respectively, making it suitable for packaging materials. The PLA/1.0% NWC film exhibited the highest crystallinity of 50.09% and high tensile strength and tensile modulus of 21.22 MPa and 11.35 MPa, respectively.
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Celulosa/química , Membranas Artificiales , Pennisetum/química , Poliésteres/química , Embalaje de Productos , NanocompuestosRESUMEN
An investigation on relationship among the physicochemical, optical and dielectric properties of the hydroxyapatite/cornstarch (HA/Cs) composites with the starch proportion of 30, 40, 50, 60, 70, 80 and 90 wt% is presented in this work. The HA/Cs composites have been characterized via FTIR, XRD, DRS and impedance analyzer. This work depicts that the strong interaction is exhibited between the hydroxyapatite nanoparticles and starch as the starch proportion increases. This increment trend results in the higher crystallinity of the HA/Cs composites. The highly crystallized HA/Cs with hydroxyapatite nucleation center presents low optical properties (diffuse reflectance and optical band gap energy). The HA/Cs composite with 80 wt% starch proportion (H2C8) show higher dielectric properties (dielectric constant, loss factor and conductivity) due to the stronger interfacial interaction and close-packed HA/Cs crystalline structure. The relationship among the physicochemical, optical and dielectric properties of the HA/Cs composite is studied in this work for potential of instrumentation design.
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Durapatita , Nanopartículas , Fenómenos Físicos , AlmidónRESUMEN
This paper provides a comprehensive analysis of the dielectric and physicochemical properties of the porous hydroxyapatite/cornstarch (HAp/Cs) composites in a new perspective. The porous composites have been characterized via SEM, FTIR, XRD and dielectric spectroscopy. The dielectric permittivity spectra were obtained in Ku-band (12.4-18.0 GHz) and it was correlated with the physicochemical properties of the porous HAp/Cs. Porous HAp/Cs composites exhibits low ε' and negative εâ³, which influenced by the microstructural morphology, interaction between Hap and Cs, as well as crystalline features due to the various proportion of the HAp/Cs. The physicochemical effect of the composites results in the dielectric polarization and energy loss. This phenomenon indicates the presence of the three obvious relaxation responses in the ε' spectrum (13.2-14.0, 15.2-16.0, and 16.6-17.4 GHz) and the negative behaviours in the εⳠspectrum. The relationships between physicochemical and dielectric properties of the porous composite facilitate the development of the non-destructive microwave evaluation test for the porous composite.
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Hidroxiapatitas/química , Nanocompuestos/química , Almidón/análogos & derivados , Microondas , Nanopartículas/química , PorosidadRESUMEN
The in vitro degradation and mechanical properties of a 3D porous Pennisetum purpureum (PP)/polylactic acid (PLA)-based scaffold were investigated. In this study, composite scaffolds with PP to PLA ratios of 0%, 10%, 20%, and 30% were immersed in a PBS solution at 37°C for 40 days. Compression tests were conducted to evaluate the compressive strength and modulus of the scaffolds, according to ASTM F451-95. The compression strength of the scaffolds was found to increase from 1.94 to 9.32MPa, while the compressive modulus increased from 1.73 to 5.25MPa as the fillers' content increased from 0wt% to 30wt%. Moreover, field emission scanning electron microscopy (FESEM) and X-ray diffraction were employed to observe and analyse the microstructure and fibre-matrix interface. Interestingly, the degradation rate was reduced for the PLA/PP20 scaffold, though insignificantly, this could be attributed to the improved mechanical properties and stronger fibre-matrix interface. Microstructure changes after degradation were observed using FESEM. The FESEM results indicated that a strong fibre-matrix interface was formed in the PLA/PP20 scaffold, which reflected the addition of P. purpureum into PLA decreasing the degradation rate compared to in pure PLA scaffolds. The results suggest that the P. purpureum/PLA scaffold degradation rate can be altered and controlled to meet requirements imposed by a given tissue engineering application.
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Pennisetum/química , Poliésteres/química , Ingeniería de Tejidos , Andamios del Tejido , Fuerza Compresiva , Módulo de Elasticidad , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Polímeros , PorosidadRESUMEN
BACKGROUND: Measuring the quality of health care is a fundamental step toward improving health care and is increasingly used in pay-for-performance initiatives and maintenance of certification requirements. Measure development to date has focused on primary care and common conditions such as diabetes; thus, the number of measures that apply to neurologic care is limited. The American Academy of Neurology (AAN) identified the need for neurologists to develop measures of neurologic care and to establish a process to accomplish this. OBJECTIVE: To adapt and test the feasibility of a process for independent development by the AAN of measures for neurologic conditions for national measurement programs. METHODS: A process that has been used nationally for measure development was adapted for use by the AAN. Topics for measure development are chosen based upon national priorities, available evidence base from a systematic literature search, gaps in care, and the potential impact for quality improvement. A panel composed of subject matter and measure development methodology experts oversees the development of the measures. Recommendation statements and their corresponding level of evidence are reviewed and considered for development into draft candidate measures. The candidate measures are refined by the expert panel during a 30-day public comment period and by review by the American Medical Association for Current Procedural Terminology (CPT) II codes. All final AAN measures are approved by the AAN Board of Directors. RESULTS: Parkinson disease (PD) was chosen for measure development. A review of the medical literature identified 258 relevant recommendation statements. A 28-member panel approved 10 quality measures for PD that included full specifications and CPT II codes. CONCLUSION: The AAN has adapted a measure development process that is suitable for national measurement programs and has demonstrated its capability to independently develop quality measures.
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Neurología/normas , Enfermedad de Parkinson/terapia , Mejoramiento de la Calidad/normas , Calidad de la Atención de Salud/normas , HumanosRESUMEN
BACKGROUND: Disparities of Parkinson's disease (PD) care have not been assessed. METHODS: We examined the medical records of 309 (83%) non-Hispanic White and 65 (17%) non-White Los Angeles veterans with PD from 1998 to 2004 to determine if care quality as measured by 10 PD indicators different by race/ethnicity. RESULTS: In multivariate modeling, adherence to indicators was higher among non-Hispanic Whites (71% vs. 65%, risk ratio 1.15, 95% CI [1.07-1.32]) compared to non-Whites. Differences in adherence by race/ethnicity were greatest for depression treatment (p<0.05). CONCLUSIONS: We detected disparities in quality of PD care, particularly in depression treatment. Future research should determine causes for these so that interventions can be designed to reduce such disparities.
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Enfermedad de Parkinson/etnología , Enfermedad de Parkinson/terapia , Calidad de la Atención de Salud , Veteranos , Negro o Afroamericano , Anciano , Anciano de 80 o más Años , Asiático , Estudios de Cohortes , Hispánicos o Latinos , Humanos , Indígenas Norteamericanos , Masculino , Persona de Mediana Edad , Indicadores de Calidad de la Atención de Salud , Estudios Retrospectivos , Población BlancaRESUMEN
BACKGROUND: Although the Expanded Disability Status Scale (EDSS) remains a widely used scale for evaluating impairments in people with multiple sclerosis (MS), EDSS assessments are infeasible in certain situations. A self-administered version of the EDSS would be potentially useful if it yielded similar results as the conventional physician-based version. METHODS: We developed a self-administered patient questionnaire to obtain ratings of neurologic impairments, and developed algorithms to estimate EDSS scores. We mailed the questionnaires to all new consecutive patients scheduled to be seen at an MS clinic. Questionnaires were completed prior to the visit and traditional EDSS ratings were made by one of two neurologists at the visit. One hundred and forty-six pairs of patient questionnaires and physician EDSS assessments were obtained. RESULTS: Kappa values for agreement between the physician's EDSS scores and the questionnaire-derived scores were 0.13 (for exact agreement), 0.39 (+/-0.5 EDSS steps), and 0.56 (+/-1.0 EDSS steps). A scatterplot showed that agreement was best at EDSS scores <3.0 and >5.0. Better agreement was obtained when patients had a higher level of education, and when the physician was more certain of the diagnosis of MS. CONCLUSIONS: While the self-assessed EDSS scores do not agree highly enough to take the place of conventional EDSS scores, they may be sufficient for MS trial screening or for assessing outcomes across broad categories of disability.