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Over the centuries, humans have developed different systems to protect surfaces from the influence of environmental factors. Protective paints are the most used ones. They have undergone considerable development over the years, especially at the turn of the 19th and 20th centuries. Indeed, between the two centuries, new binders and pigments have been introduced in the constituent materials of paints. The years in which these compounds have been introduced and spread in the paint market allow them to be defined as markers for the dating of paints and painted artifacts. The present work is focused on the study of the paints of two vehicles of the Frankfurt Museum of Communication, i.e., a carriage and a cart, that was designed for the German Postal and Telecommunications Service roughly between 1880 and 1920. The characterization of the paints was performed through in situ non-invasive techniques, i.e., portable optical microscopy and multispectral imaging, and laboratory non-destructive techniques, i.e., FT-IR ATR spectroscopy and SEM-EDS. The analytical investigation and the comparison with the data reported in the literature allowed us to determine the historicity of the paints, which are all dated before the 1950s.
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Background: The Gyr breed is widely used in Colombian low tropic dairy production systems. During the last 10 years, the Asociación Colombiana de Criadores de Ganado Cebú ASOCEBU, has been leading a dairy milk control program which led to the creation of a dataset that permits to carry out the first analysis of milk yield in Gyr cattle in the country using records from several herds. Objectives: To study milk production dynamics of Gyr cattle in the Colombian low tropic through the estimation of lactation curves and four derived production parameters: total milk yield between 5 and 305 days (TMY305), peak milk yield (PMY), days at peak (DP) and persistency (P). Methods: 13,798 daily milk yield records from 1,510 cows performing in 103 herds were used; the total number of lactations was 2,480. Four models were considered: Wood, Wiltmink, Papajcsik & Bordero, and a second-degree polynomial. Mean square error, mean absolute error, mean square error of prediction, Akaike and Bayesian information criteria were used to select the model better describing each lactation using the majority rule, that is, the model selected by most criteria was the chosen one. The shape of each fitted lactation curve was checked using basic results from calculus which permitted the classification of the estimated curves into two groups: typical and atypical; only typical functions were used to compute the four aforementioned production parameters. Results: The second-order polynomial was the model most frequently selected, while the Papajcsik & Bordero model had the lowest frequency. Average TMY305, PMY, DP and P were 3,489.86 kg, 17.28 kg, 57.17 days, and 0.83, respectively, with coefficients of variation: 0.27, 0.21, 0.41, and 0.16. Conclusions: This study permitted to identify individuals with outstanding phenotypic performance. To the best of our knowledge, this is the first study of this kind involving thousands of lactations from Gyr cows performing in several regions of Colombian low tropic.
Antecedentes: La raza Gyr es ampliamente utilizada en las lecherías de trópico bajo en Colombia. Durante los últimos 10 años, la Asociación Colombiana de Criadores de Ganado Cebú ASOCEBU, ha liderado un programa de control lechero que generó una base de datos que permite llevar a cabo el primer análisis de producción de leche de la raza Gyr en el país, considerando individuos de varias fincas. Objetivos: Caracterizar la dinámica de producción de leche de ganado Gyr en el trópico bajo colombiano mediante la estimación de curvas de lactancia y cuatro parámetros de producción derivados: producción total entre 5 y 305 días (TMY305), pico de lactancia (PMY), días al pico (DP) y persistencia (P) Métodos: Se utilizaron 13.798 registros de producción diaria de leche de 1.510 vacas provenientes de 103 fincas, el total de lactancias fue 2.480. Se consideraron cuatro modelos: Wood, Wiltmink, Papajcsik & Bordero, y un polinomio de segundo grado. Los criterios usados para elegir el modelo que mejor describió cada lactancia fueron: error cuadrático medio, error absoluto medio, error cuadrático medio de predicción, criterio de información de Akaike y criterio de información Bayesiano. Se utilizó el criterio de mayoría, esto es, el modelo seleccionado fue aquel elegido por más criterios. La forma de cada una de las curvas de lactancia estimadas fue chequeada utilizando resultados básicos del cálculo, esto permitió clasificar las curvas estimadas en dos grupos: típicas y atípicas; solamente las curvas típicas fueron empleadas para calcular los cuatro parámetros antes mencionados. Resultados: El polinomio de segundo grado fue el modelo que se seleccionó con mayor frecuencia, mientras que el modelo Papajcsik & Bordero tuvo la menor frecuencia. Los promedios para TMY305, PMY, DP y P fueron 3.489,86 kg, 17,28 kg, 57,17 días, y 0,83, respectivamente, con coeficientes de variación 0,27, 0,21, 0,41 y 0,16 Conclusiones: Este estudio permitió identificar individuos con desempeño fenotípico sobresaliente. De acuerdo al estado del arte, este es el primer estudio de este tipo que considera miles de lactancias de vacas Gyr provenientes de varias regiones del trópico bajo colombiano.
Antecedentes: Gir é uma raça Bos indicus amplamente utilizada em sistemas de produção leiteira no trópico baixo Colombiano. A Asociación Colombiana de Criadores de Ganado CebúASOCEBU, lidera um programa de controle de leite nos últimos 10 anos, o que permitiu à coleta de um conjunto de dados para realizar a primeira análise de produção de leite em bovinos Gir no país com informações de vários rebanhos. Objetivo: Estudar a dinâmica da produção de leite por meio da estimativa das curvas de lactação e quatro parâmetros de produção derivados: produção total de leite entre 5 e 305 dias (TMY305), produção de leite no pico de lactação (PMY), dias em produção de leite no pico de lactação (DP) e persistência (P). Métodos: Foram utilizados 13.798 registros de produção diária de leite de 1.510 vacas de 103 fazendas , totalizando 2.480 lactações. Foram considerados quatro modelos: Wood, Wiltmink, Papajcsik & Bordero e um polinômio de segundo grau. Para selecionar o modelo que melhor descreve cada lactação foram utilizados os seguintes critérios: erro quadrado médio, erro absoluto médio, e erro quadrado médio de predição. O modelo selecionado pela maioria dos parâmetros, de acordo com os critérios de informação de Akaike e Bayesiano, foi o escolhido. A forma de cada curva de lactação ajustada foi verificada utilizando os resultados básicos do cálculo, isso permitiu classificar as curvas estimadas em dois grupos: típico e atípico, e apenas funções típicas foram utilizadas para calcular os quatro parâmetros de produção acima mencionados Resultados: O polinômio de segunda ordem foi o modelo mais frequentemente selecionado, enquanto o modelo Papajcsik & Bordero apresentou a menor frequência. A média de TMY305, PMY, DP e P foram 3.489,86 kg, 17,28 kg, 57,17 d e 0,83, respectivamente, com coeficientes de variação de 0,27, 0,21, 0,41 e 0,16. Conclusões: Este estudo permitiu identificar indivíduos com excelente desempenho fenotípico. De acordo com a literatura atual, este é o primeiro estudo envolvendo milhares de lactações de vacas Gir em várias regiões do trópico baixo colombiano.
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BACKGROUND: Multiple sclerosis treatment has changed in the last years with the emergence of new disease-modifying therapies (DMTs). Despite a better efficacy profile, these drugs raise concerns about infectious risk, which needs to be mitigated. OBJECTIVE: To analyze the results of a systematic collaborative approach between Neurology and Infectious Diseases (ID) Departments in the management of infectious risk and complications in MS patients treated with DMT. METHODS: Retrospective collection of MS patients' demographic and clinical data from clinical records of MS and ID outpatient clinics (2011-2017). RESULTS: We included 149 patients: most had evidence of previous contact with Herpesviridae, and half of them were not immune to hepatitis A and B viruses (HAV and HBV). Vaccines for HAV, HBV, and Streptococcus pneumoniae were administered in 91%, 78%, and 88% of non-immune patients, respectively. JC virus serology monitoring prevented natalizumab (NTZ) initiation or prompted its switch in 34/122 patients. Forty patients had latent tuberculosis, in which 88% were treated. Infectious events occurred in 33 patients, mostly mild urinary, respiratory, and herpes virus group infections. Only three patients required inpatient care. CONCLUSION: Facing the expansion of the new DMT, we highlight the benefits of an interdisciplinary approach for safer use of the chosen treatment.
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INTRODUCTION: Neuromyelitis optica spectrum disorder (NMOSD) is a rare disorder in which astrocyte damage and/or demyelination often cause severe neurological deficits. OBJECTIVE: To identify Portuguese patients with NMOSD and assess their epidemiological/clinical characteristics. METHODS: This was a nationwide multicenter study. Twenty-four Portuguese adult and 3 neuropediatric centers following NMOSD patients were included. RESULTS: A total of 180 patients met the 2015 Wingerchuk NMOSD criteria, 77 were AQP4-antibody positive (Abs+), 67 MOG-Abs+, and 36 seronegative. Point prevalence on December 31, 2018 was 1.71/100,000 for NMOSD, 0.71/100,000 for AQP4-Abs+, 0.65/100,000 for MOG-Abs+, and 0.35/100,000 for seronegative NMOSD. A total of 44 new NMOSD cases were identified during the two-year study period (11 AQP4-Abs+, 27 MOG-Abs+, and 6 seronegative). The annual incidence rate in that period was 0.21/100,000 person-years for NMOSD, 0.05/100,000 for AQP4-Abs+, 0.13/100,000 for MOG-Abs+, and 0.03/100,000 for seronegative NMOSD. AQP4-Abs+ predominated in females and was associated with autoimmune disorders. Frequently presented with myelitis. Area postrema syndrome was exclusive of this subtype, and associated with higher morbidity/mortality than other forms of NMOSD. MOG-Ab+ more often presented with optic neuritis, required less immunosuppression, and had better outcome. CONCLUSION: Epidemiological/clinical NMOSD profiles in the Portuguese population are similar to other European countries.
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Neuromielitis Óptica , Adulto , Acuaporina 4 , Autoanticuerpos , Estudios Epidemiológicos , Femenino , Humanos , Glicoproteína Mielina-Oligodendrócito , Neuromielitis Óptica/epidemiología , Portugal/epidemiologíaRESUMEN
BACKGROUND: Therapeutic inertia (TI) is defined as a failure to initiate or intensify treatments despite evidence of disease activity. Its prevalence and determining factors in Relapsing-Remitting Multiple Sclerosis (RRMS) patients in Portugal are not known. The main objective of this work was to ascertain the prevalence of TI in RRMS and its determining factors. METHODS: We conducted a multicentre retrospective observational study of RRMS patients followed in MS Clinics of six Portuguese hospitals with at least one medical appointment in 2018. TI was defined as the absence of treatment initiation or intensification when therapeutic goals were unmet, that is when there was evidence of disease activity based on the definition of "no evidence of disease activity" (NEDA) which refers to absence of clinical relapses, absence of disease progression measured by expanded disability status scale (EDSS) and absence of new disease activity (new T2 lesions/enhancing lesion) on magnetic resonance imaging (MRI) over the period of observation. RESULTS: We included 427 patients with RRMS meeting inclusion criteria, 69.6% females, with a mean age of 41.66 years old. The mean age at diagnosis was 33.17 years old and the average number of years since diagnosis was 8.72. MS relapses were reported on 54 patients. Moderate to severe relapses were reported in 59.3%. Median EDSS score was 1.5. Intention to get pregnant was explicit in 39 patients, representing 18.8% of the women at childbearing age. Among the 365 patients who had an MRI, 23.8% had new T2 lesions and 7.4% had enhancing lesions. Regarding DMT, 72.8% were treated with interferon, glatiramer acetate, teriflunomide, or dimethyl fumarate, 20.6% were under fingolimod, natalizumab, rituximab, and cladribine, and the remaining 6.6% were without treatment. Adverse events were reported in 12.9% of patients, and 10.1% mentioned preferences regarding the treatment. TI was present in 80 (18.7%) patients, representing 54.8% of those with potential to inertia. Patients with a radiologically less active disease, who were already on a DMT and who had no adverse events from their current treatment were more likely to have TI (p<0,05). Also, patients followed in centers classified as higher level of care (level 1) had more TI compared with patients followed in centers of levels 2 and 3. CONCLUSION: TI was present in 1 in 5 patients, exceeding half of the sample with the potential to inertia, corroborating the high prevalence of TI in other studies. The determining factors of TI were the absence of relapses or the occurrence of mild relapses, being already on DMT, absence of adverse events, and follow-up in higher care level centers. TI is a topic rarely addressed in MS and this work highlights the importance of therapeutic optimization in these patients. Further studies should be held to explore the factors that influence TI once they have a great impact on therapeutic decisions.
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Esclerosis Múltiple Recurrente-Remitente , Esclerosis Múltiple , Adulto , Femenino , Clorhidrato de Fingolimod , Acetato de Glatiramer , Humanos , Masculino , Esclerosis Múltiple Recurrente-Remitente/diagnóstico por imagen , Esclerosis Múltiple Recurrente-Remitente/tratamiento farmacológico , Esclerosis Múltiple Recurrente-Remitente/epidemiología , Natalizumab , EmbarazoRESUMEN
BACKGROUND: Several disease-modifying therapies (DMTs) have emerged in the last two decades for the treatment of multiple sclerosis (MS). The increasing use of these therapies has enhanced the need to study its impact on long-term disease progression and on the natural history of MS. This study aimed to characterize a Portuguese MS patient cohort in what concerns the natural history of disease by exploring differences throughout 3 decades. METHODS: Longitudinal, retrospective, non-interventional study. Patients aged ≥ 18 years old, with confirmed diagnosis of relapsing-remitting MS (RRMS), were included. Biodemographic and clinical characteristics (MS diagnosis, patient follow-up, relapses, treatment, and exams) were assessed and compared according to the first appointment date throughout 10-year spans (1987-1996; 1997-2006; 2007-2016). RESULTS: 548 patients were included in this analysis. Significant differences were observed between decades for evoked potential (EP) and cerebrospinal fluid (CSF) exams conducted at diagnosis, the first with less expression on the last decade; the median number of relapses per year (higher in the subgroup 07-16); EDSS at baseline and at last appointment (both higher in the subgroup 87-96); and the percentage of patients achieving EDSS 3.0 and EDSS 6.0 (increased in the subgroup 87-96). Additionally, time from diagnosis to first treatment was significantly lower in patients from the most recent decade, and a greater percentage of such patients, compared to the other two subgroups, was, at last appointment, under a second line DMT. CONCLUSION: In general, our study reflects findings from longitudinal studies on MS progression already published in the literature. In recent years, the growing number of more effective DMTs, along with earlier disease detection, and improvements in access to healthcare appear to have had a positive impact on patients' access to treatment and, consequently, disease progression. Additional studies, with increased follow up time, are needed to further investigate the effect of treatment improvement in the natural history of MS.
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Esclerosis Múltiple Recurrente-Remitente , Esclerosis Múltiple , Adolescente , Estudios de Cohortes , Humanos , Esclerosis Múltiple Recurrente-Remitente/diagnóstico , Esclerosis Múltiple Recurrente-Remitente/tratamiento farmacológico , Esclerosis Múltiple Recurrente-Remitente/epidemiología , Portugal/epidemiología , Estudios RetrospectivosRESUMEN
BACKGROUND AND PURPOSE: The mechanisms linking systemic inflammation to poor outcome in ischemic stroke are not fully understood. The authors investigated if peripheral inflammation following reperfusion therapy leads to an increase in cerebral edema (CED), thus hindering the clinical recovery. METHODS: We designed a single-center study conducted at Centro Hospitalar Universitário São João between 2017 and 2019. Inclusion criteria were being adult, having an anterior circulation acute ischemic stroke, and receiving reperfusion therapy. Neutrophil-to-lymphocyte, platelet-to-lymphocyte ratios, and the systemic inflammatory response syndrome criteria were determined. The presence and grade of CED were evaluated on the computed tomography performed 24 hours following event. The clinical outcomes included early neurological deterioration and functional dependence at 90 days. Adjusted odds ratio and 95% CI were obtained by ordinal and logistic regression models. Optimal cutoff values were defined using receiver operating characteristic analysis in the training cohort and validated in an independent data set. RESULTS: Five hundred fifty-three patients were included. Neutrophil-to-lymphocyte increased with higher degrees of CED at 24 hours (adjusted odds ratio, 1.34 [1.09-1.68], P<0.01) and was associated with early neurological deterioration (adjusted odds ratio, 1.30 [1.04-1.63], P<0.05) and poor functional status at 90 days (adjusted odds ratio, 1.79 [1.28-2.48], P<0.01). Platelet-to-lymphocyte was not associated with the outcomes. Systemic inflammatory response syndrome was related to CED due to altered white blood cell counts. Neutrophil-to-lymphocyte was the best predictor with an area under the curve around 0.7. Neutrophil-to-lymphocyte ≥7 had and accuracy, sensitivity, and specificity around 60%. CONCLUSIONS: Increased systemic inflammation is linked to the severity of CED early after reperfusion therapy in stroke. Easily obtained inflammatory markers convey early warning alerts for patients at risk of severe neurological complications with an impact on long-term functional outcome. CED quantification should be included as an end point in proof-of-concept trials in immunomodulation in stroke.
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Linfocitos/citología , Neutrófilos/citología , Reperfusión/métodos , Accidente Cerebrovascular/sangre , Accidente Cerebrovascular/terapia , Adolescente , Adulto , Anciano , Plaquetas , Edema Encefálico/patología , Recuento de Células , Edema , Humanos , Inflamación , Recuento de Linfocitos , Persona de Mediana Edad , Oportunidad Relativa , Estudios Prospectivos , Curva ROC , Análisis de Regresión , Estudios Retrospectivos , Trombectomía/métodos , Tomografía Computarizada por Rayos X , Resultado del Tratamiento , Adulto JovenRESUMEN
The mining areas of the Middle Atlas, already inhabited in the Neolithic period, have been under the influences of different cultures, firstly Phoenician, then Punic or Ibero-Punic, Berber, Roman and finally Islamic. The impact of external cultures on the evolution and development of ancient metallurgy in the north-central Atlas region and the Southern Rift occurred since prehistoric times to Arab domination in the Middle Ages. This study proposes the development of an up-to-date protocol for archaeometallurgical investigation, based on the correlation between the chemical-physical analysis of the pyrometallurgical materials and the contextual systematic geoarchaeological excavations. The microchemical analysis has been carried out on opportunely selected pyrometallurgical materials, coming from different mining areas of the Middle Atlas regions in Morocco (Tabarouch for Cu and Aouam for Pb/Ag) in order to understand the evolution of the technological knowledge in archaeometallurgical work of local people. After that, the analytical results have been included in a Geographic Information System (GIS) software with the aim of creating an easily usable database that will support multidisciplinary research on the ancient metallurgical activities also with its future development and implementation. The GIS application could indeed correlate all the data coming from different extraction/work sites, present in the exploited mining veins. Furthermore, the GIS application is a starting point for an integrated study of the different mining archaeological sites in the Mediterranean basin proposing an innovative method of data exchange of archaeological, physical and geological chemical results.
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Difusión de la Información , Minería , Humanos , Metalurgia , Marruecos , Programas InformáticosRESUMEN
Acute disseminated encephalomyelitis (ADEM) is a demyelinating disorder that usually affects the central nervous system (CNS) after an infection and/or vaccination. It is more common in infancy. Here we present a case of late onset ADEM. A 71-year-old male was admitted to the emergency department due to speech difficulty and somnolence. Upon neurological examination he had a mixed aphasia. He performed a brain computed tomography which showed multiple white matter hypodense lesions. After admission to the neurology ward, he performed a lumbar puncture which showed a mildly inflammatory cerebrospinal fluid, negative serological testing and negative oligoclonal bands. Brain magnetic resonance imaging (MRI) confirmed the presence of multiple T2 hyperintense lesions, extensive bilateral frontoparietal lesions with abundant perilesional edema, four with gadolinium enhancement in an open-ring pattern and no mass effect. Anti-aquaporin 4 antibody, virologic and bacteriologic blood testing, screening of autoimmune disorders and occult neoplasm were all unremarkable. He was treated with intravenous methylprednisolone (1 gr) during five days and started to recover, maintaining a slight verbal fluency deficiency. Post-treatment brain MRI showed reduction of previous lesions, corroborating the probable inflammatory/demyelinating etiology. After discharge he maintained follow-up at the neurology outpatient clinic and he is currently asymptomatic with no new lesions and further reduction of the previous ones on follow-up MR scan. Both clinical follow-up of the patient, revealing a monophasic course with complete recovery, and temporal evolution of his brain lesions were essential to establish a diagnosis of ADEM in a septuagenarian patient, in whom other diagnoses have to be considered.
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The article analyzes the grave goods contained in the tomb n. 116 in the Necropolis of Castellaccio in Rome (IV Cent. B.C.-IV cent. A.C.) and offers a description of a bracelet and some rings, analyzed by electronic microscope and by EDS.
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Cementerios/historia , Joyas/historia , Historia Antigua , Ciudad de RomaRESUMEN
BACKGROUND: The use of computerized image analysis for the study of nuclear texture features has provided important prognostic information for several neoplasias. Recently fractal characteristics of the chromatin structure in routinely stained smears have shown to be independent prognostic factors in acute leukemia. In the present study we investigated the influence of the fractal dimension (FD) of chromatin on survival of patients with multiple myeloma. METHODOLOGY: We analyzed 67 newly diagnosed patients from our Institution treated in the Brazilian Multiple Myeloma Study Group. Diagnostic work-up consisted of peripheral blood counts, bone marrow cytology, bone radiograms, serum biochemistry and cytogenetics. The International Staging System (ISS) was used. In every patient, at least 40 digital nuclear images from diagnostic May-Grünwald-Giemsa stained bone marrow smears were acquired and transformed into pseudo-3D images. FD was determined by the Minkowski-Bouligand method extended to three dimensions. Goodness-of-fit of FD was estimated by the R(2) values in the log-log plots. The influence of diagnostic features on overall survival was analyzed in Cox regressions. Patients that underwent autologous bone marrow transplantation were censored at the day of transplantation. PRINCIPAL FINDINGS: Median age was 56 years. According to ISS, 14% of the patients were stage I, 39% were stage II and 47% were stage III. Additional features of a bad prognosis were observed in 46% of the cases. When stratifying for ISS, both FD and its goodness-of-fit were significant prognostic factors in univariate analyses. Patients with higher FD values or lower goodness-of-fit showed a worse outcome. In the multivariate Cox-regression, FD, R(2), and ISS stage entered the final model, which showed to be stable in a bootstrap resampling study. CONCLUSIONS: Fractal characteristics of the chromatin texture in routine cytological preparations revealed relevant prognostic information in patients with multiple myeloma.
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Cromatina/metabolismo , Eosina Amarillenta-(YS) , Fractales , Azul de Metileno , Mieloma Múltiple/patología , Sobrevida , Adulto , Anciano , Anciano de 80 o más Años , Trasplante de Médula Ósea , Femenino , Humanos , Masculino , Persona de Mediana Edad , Mieloma Múltiple/metabolismo , Mieloma Múltiple/cirugía , Pronóstico , Estudios RetrospectivosRESUMEN
Despite the numerous literature data available in the field of calcium phosphate bone cements, the mechanism and kinetics of their hardening, both of which are of great importance for cements application, in most cases, is unknown. In this work, the mechanism and kinetics of hardening of two novel high-strength calcium phosphate bone cements were studied using the energy dispersive X-ray diffraction technique, which allows rapid collection of the patterns. The phase transformations occurring on the setting and hardening processes were monitored in situ. Containing minimal quantity of components, whose mixing leads to the formation of cements with pH close to neutral, the cements under study are simple in handling. The main component of both formulations is tetracalcium phosphate. In both cements, the effect of the addition of high- and low-molecular weight chitosan on phase development and kinetics was investigated in detail. One of the cements has the compressive strength of about 70 MPa, whereas the strength of the other, containing Ca(3)Al(2)O(6), is much higher, about 100 MPa. This latter cement could be regarded as an alternative to the common low-strength bioresorbable brushite cements.
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Cementos para Huesos/química , Fosfatos de Calcio/química , Quitosano/química , Fuerza Compresiva , Cristalización , Dureza , Pruebas de Dureza , Humanos , Concentración de Iones de Hidrógeno , Técnicas In Vitro , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Peso Molecular , Difracción de Polvo , Factores de Tiempo , Difracción de Rayos XRESUMEN
Carbonated hydroxyapatite (CHA)-coated titanium can find wide applications as bone substitute implant in bone and dental surgery and orthopedics, promoting osseointegration with a host bone and ensuring biocompatibility and bioactivity. In this work, carbonated hydroxyapatite films were prepared on titanium substrates by pulsed laser deposition at different substrate temperatures ranging from 30 to 750 degrees C. The properties of films were investigated by scanning electron microscopy, atomic force microscopy, energy-dispersive X-ray diffraction, and Fourier transform infrared spectroscopy. Vickers microhardness measurements of the composite film-substrate systems were performed, and the intrinsic hardness of films was separated from the composite hardness using a "law-of-mixtures" approach and taking into account the indentation size effect. The prepared CHA films are nearly stoichiometric with a Ca/P atomic ratio of 2.0-2.2. The films deposited in the 30-500 degrees C temperature range are about 9 microm thick, amorphous, having an average roughness of 60 nm. At higher temperature, 700-750 degrees C, the films are about 4 microm thick, show a finer surface morphology and an average roughness of 20 nm. At 750 degrees C the films are amorphous, whereas at 700 degrees C they are crystalline and textured along the (202) and (212) directions. The intrinsic hardness of the films increased with an increase in substrate temperature, being as low as 5 GPa at 30 degrees C and reaching a high value of 28 GPa at 700 degrees C. The rich information gained by the joint use of the mentioned techniques allowed a comprehensive characterization of this system.
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Sustitutos de Huesos/química , Carbono/química , Hidroxiapatitas/química , Calcio/química , Química Física/métodos , Rayos Láser , Ensayo de Materiales , Microscopía de Fuerza Atómica/métodos , Microscopía Electrónica de Rastreo/métodos , Fosfatos/química , Presión , Espectroscopía Infrarroja por Transformada de Fourier/métodos , Temperatura , Titanio/química , Difracción de Rayos XRESUMEN
Titanium has limitations in its clinical performance in dental and orthopaedic applications. This study describes a coating process using pulsed laser deposition (PLD) technology to produce surfaces of titanium carbide (TiC) on titanium substrates and evaluates the biological response both in vitro and in vivo. X-ray photoelectron spectroscopy (XPS) analysis revealed the presence of 18.6-21.5% TiC in the surface layer, accompanied by oxides of titanium 78.5-81.4% in the following concentrations: 11.1-13.0% Ti(2)O(3), 50.8-55.8% TiO(2), 14.5-14.7% TiO. Expression of genes central to osteoblast differentiation (alkaline phosphatase, A2 pro-collagen type 1, osteocalcin, BMP-4, TGFbeta and Cbfa-1) were up-regulated in all cell lines (primary human osteoblasts, hFOB1.19 and ROS.MER#14) grown on TiC compared with uncoated titanium when measured by semiquantitative PCR and real time-PCR, whilst genes involved in modulation of osteoclastogenesis and osteoclast activity (IL-6 and M-CSF) were unchanged. Bone density was shown to be greater around TiC-coated implants after 2 and 4 weeks in sheep and both 4 and 8 weeks in rabbits compared to uncoated titanium. Rapid bone deposition was demonstrated after only 2 weeks in the rabbit model when visualized with intravital staining. It is concluded that coating with TiC will, in comparison to uncoated titanium, improve implant hardness, biocompatibility through surface stability and osseointegration through improved bone growth.
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Oseointegración/efectos de los fármacos , Titanio/química , Titanio/farmacología , Animales , Sustitutos de Huesos/química , Línea Celular , Movimiento Celular , Forma de la Célula , Materiales Biocompatibles Revestidos/química , Expresión Génica , Humanos , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Osteoblastos/citología , Osteoblastos/metabolismo , Conejos , Ratas , Análisis Espectral , Especificidad por SustratoRESUMEN
Calcium phosphate coatings are known to enhance long-term fixation, reliability and promote osteointegration of cementless titanium-based implant devices. This study was aimed at the pulsed laser deposition of calcium phosphate coatings onto titanium using hydroxyapatite and hydroxyapatite-fluorapatite targets. The deposition was carried out at the high laser beam fluence conditions, about 12 J/cm(2). The coatings were characterized with respect to their morphology, phase composition and hardness. X-ray energy dispersive analysis revealed the coatings retain their elemental composition, and fluoride content within the film is the same as in the initial target. However, unlike sintered targets, the deposited films contain no apatite-like phases. The hardness of the films, about 18 GPa, is surprisingly high compared to that of hydroxyapatite and hydroxyapatite-fluorapatite ceramic targets. The deposited coatings of 2.7-2.9 microm thickness have uniform and dense microstructure, containing the solidified droplets of the expulsed from the target phase. The uncommon structure and hardness of the films can be attributed to the melting and phase decomposition of the initial material in the laser plasma.