Green composites based on thermoplastic starch reinforced with micro- and nano-cellulose by melt blending - A review.

Starch is a biodegradable biopolymer, a sustainable material that can replace conventional petrochemical-based plastics. However, starch has some limitations, as it must be processed by heating and treated mechanically with a plasticizer to become thermoplastic starch (TPS). Different variables such as mixing speeds, amount, and kind of plasticizers play a vital role in preparing TPS by melting. Despite this, the properties of the TPS are not comparable with those of traditional plastics. To overcome this limitation, microcellulose or nanocellulose is added to TPS by melt mixing, including the extrusion and internal mixing process, which enables large-scale production. This review aims to compile several studies that evaluate the effect of plasticizers, as well as the relevance of incorporating different cellulosic fillers of different dimensions on the properties of TPS obtained by melt mixing. Potential applications of these materials in food packaging, biomedical applications, and other opportunities are also described.

Fabrication and assessment of bifunctional electrospun poly(l-lactic acid) scaffolds with bioglass and zinc oxide nanoparticles for bone tissue engineering.

Electrospun scaffolds based on poly(l-lactic acid) (PLLA) with bioglass (n-BG) and zinc oxide (n-ZnO), and mixture of both, were developed to design bifunctional biomaterials with enhanced bioactive and biocidal properties. The presence of n-BG increased the fiber diameter of the pure PLA from 1.5 ± 0.3 µm to 3.0 ± 0.8 µm for 20 wt%. ZnO and the mixed nanoparticles did not significantly affect the morphology. The mechanical properties decreased with the presence of nanoparticles. Scaffolds based on PLA/n-BG promoted hydroxyapatite (HA) formation in simulated body fluid (SBF) that was inhibited with the presence of ZnO. Notably, mixed particles produced bioactivity although at longer times. The incorporation of n-ZnO produced a biocidal capacity against S. aureus in the polymeric scaffold, reaching a viability reduction of 60 % after 6 h of exposure. When both types of nanoparticles were combined, the bacterial viability reduction was 30 %. Pure PLA scaffolds and the composites with n-BG showed good ST-2 bone marrow-derived cell line viability, scaffolds with n-BG (pure or mixture) presented lower viability. Results validated the use of both n-BG and n-ZnO fillers for the development of novel bifunctional PLA-based scaffolds with both bioactive and biocidal properties for bone tissue engineering applications.

Effect of Gelatin Coating and GO Incorporation on the Properties and Degradability of Electrospun PCL Scaffolds for Bone Tissue Regeneration.

Polymer-based nanocomposites such as polycaprolactone/graphene oxide (PCL/GO) have emerged as alternatives for bone tissue engineering (BTE) applications. The objective of this research was to investigate the impact of a gelatin (Gt) coating on the degradability and different properties of PCL nanofibrous scaffolds fabricated by an electrospinning technique with 1 and 2 wt% GO. Uniform PCL/GO fibers were obtained with a beadless structure and rough surface. PCL/GO scaffolds exhibited an increase in their crystallization temperature (Tc), attributed to GO, which acted as a nucleation agent. Young's modulus increased by 32 and 63% for the incorporation of 1 and 2 wt% GO, respectively, in comparison with neat PCL. A homogeneous Gt coating was further applied to these fibers, with incorporations as high as 24.7 wt%. The introduction of the Gt coating improved the hydrophilicity and degradability of the scaffolds. Bioactivity analysis revealed that the hydroxyapatite crystals were deposited on the Gt-coated scaffolds, which made them different from their uncoated counterparts. Our results showed the synergic effect of Gt and GO in enhancing the multifunctionality of the PCL, in particular the degradability rate, bioactivity, and cell adhesion and proliferation of hGMSC cells, making it an interesting biomaterial for BTE.

Mechanical and Antimicrobial Polyethylene Composites with CaO Nanoparticles.

Low-density polyethylene composites containing different sizes of calcium oxide (CaO) nanoparticles were obtained by melt mixing. The CaO nanoparticles were synthesized by either the sol-gel or sonication methods, obtaining two different sizes: ca. 55 nm and 25 nm. These nanoparticles were used either as-synthesized or were modified organically on the surface with oleic acid (Mod-CaO), at concentrations of 3, 5, and 10 wt% in the polymer. The Mod-CaO nanoparticles of 25 nm can act as nucleating agents, increasing the polymer's crystallinity. The Young's Modulus increased with the Mod-CaO nanoparticles, rendering higher reinforcement effects with an increase as high as 36%. The reduction in Escherichia coli bacteria in the nanocomposites increased with the amount of CaO nanoparticles, the size reduction, and the surface modification. The highest antimicrobial behavior was found in the composites with a Mod-CaO of 25 nm, presenting a reduction of 99.99%. This strong antimicrobial effect can be associated with the release of the Ca2+ from the composites, as studied for the composite with 10 wt% nanoparticles. The ion release was dependent on the size of the nanoparticles and their surface modification. These findings show that CaO nanoparticles are an excellent alternative as an antimicrobial filler in polymer nanocomposites to be applied for food packaging or medical devices.

Tratamento com radio e quimioterapia do carcinoma epidermóide do canal anal: experiência do hospital Barão de Lucena / Radiochemotherapy for squamous cell carcinoma of the anal canal: Barao de Lucena hospital experience

Objetivos: Apresentar os resultados e analisar as variáveis implicadas no tratamento e prognóstico do carcinoma epidermóide do canal anal tratado através da radio e quimioterapia no Hospital Barão de Lucena-SUS-PE. Metodologia: Análise dos prontuários de pacientes com diagnóstico de câncer do canal anal submetidos a tratamento radioquimioterápico. O período de acompanhamento foi de junho de 1989 a junho de 2005. Foram incluídos os pacientes com diagnóstico histológico de câncer de canal anal, enquadrados nos estadios I, II, IIIa e IIIb, submetidos a dois ciclos de quimioterapia com 5-fluorouracil (5-FU) na dose de 1g/m²/dia em infusão contínua de 96 horas e cisplatino na dose de 100mg/m² administrado em 6 horas no segundo dia de infusão de cada ciclo, administrados na primeira e terceira semanas do esquema de tratamento radioterápico. Resultados: Avaliamos 108 prontuários de pacientes que preencheram os critérios do protocolo. O tempo médio de seguimento foi de 51 meses (1-182 meses). Houve predomínio do gênero feminino (81,5 por cento dos pacientes). A idade variou de 33 a 83 anos (média de 59 anos). O tipo histológico mais freqüente foi o carcinoma de células escamosas (80,6 por cento dos casos). Em 21 pacientes, foi diagnosticado carcinoma basalóide. Quanto ao grau de diferenciação, prevaleceu o tipo moderadamente diferenciado (61 por cento dos pacientes com carcinoma de células escamosas). O índice de resposta inicial completa foi de 89,8 por cento. Onze pacientes persistiram com tumor após o tratamento radio e quimioterápico. O índice de resposta inicial completa foi menor nos estadios IIIa e IIIb em relação aos estadios I e II com significância estatística (p<0,05). 14 pacientes evoluíram com recidiva tumoral, oito com recidiva local (7,4 por cento) e seis (5,5 por cento) com recidiva linfática e à distância. CONCLUSÕES: O tratamento radioquimioterápico exclusivo do carcinoma epidermóide do canal anal, tem índice de resposta completo bastante elevado co...

Objectives: To present the results and analyze the variables involved in the treatment and prognosis of squamous cell carcinoma of the anal canal treated by radiotherapy and chemotherapy at the Hospital Barao de Lucena-SUS-PE. Methodology: Analysis of medical records of patients diagnosed with anal cancer treated by chemoradiation. The monitoring period was from June 1989 to June 2005. We included patients with histologically confirmed cancer of the anal canal, framed in stages I, II, IIIa and IIIb, underwent two cycles of chemotherapy with 5-fluorouracil (5-FU) at a dose of 1g / m² / day continuous infusion 96 hours and cisplatin at a dose of 100 mg / m² administered at 6 hours the second day of infusion of each cycle, administered on the first and third weeks of radiotherapy treatment regimen. Results: We evaluated records of 108 patients who met the criteria of the protocol. The mean follow-up was 51 months (1-182 months). There were more females (81.5 percent of patients). The age ranged from 33 to 83 years (mean 59 years). The most common histological type was squamous cell carcinoma (80.6 percent of cases). In 21 patients, was diagnosed Basaloid carcinoma. Regarding the degree of differentiation, the most prevalent type was moderately differentiated (61 percent of patients with squamous cell carcinoma). The rate of initial complete response was 89.8 percent. Eleven patients had persistent tumor after radiotherapy and chemotherapy. The initial response rate was lower in complete stages IIIa and IIIb compared to stages I and II with statistical significance (p <0.05). 14 patients developed recurrence, eight with local recurrence (7.4 percent) and six (5.5 percent) with lymphatic recurrence and distance. CONCLUSIONS: The chemoradiation treatment of unique cell carcinoma of the anal canal, have complete response rate very high with acceptable morbidity. Surgical treatment still has its value in cases of persistent injury and / or local recurrence, with sati...

Tipo de crisis epiléctica y no epiléctica en pacientes mayores de 12 años / Epileptic and non epileptic seizures in patients over 12 years ald

El presente estudio tuvo como objetivo determinar la frecuencia con que se presentan los tipos de crisis epiléptica y crisis no epiléptica en pacientes, mayores de 12 años según sexo, edades de la presentación de la primera crisis epiléptica que acuden a la Consulta Externa de Neurología del Hospital Central Universitario Antonio María Pineda (HCUAMP). Se diseñó un estudio transversal, constituido por 230 pacientes con diagnóstico de crisis epiléptica, entre enero-junio de 1996. Los resultados demostraron que una cuarta parte de pacientes presentaron crisis epiléptica (25,26 por ciento). La razón crisis epiléptica-crisis no epiléptica fue 6:1. Se encontró un ligero predominio de crisis epiléptica y no epiléptica en pacientes femeninos. La mayoría de la crisis epiléptica (45,64 por ciento) se presentaron en pacientes entre 12 y 21 años. Se presentó un leve predominio de la crisis generalizadas (50,43 por ciento) sobre la crisis parciales (47,83 por ciento). La crisis generalizadas tónico clónica fueron la más frecuentes (28,69 por ciento), seguido por las crisis parciales que evolucionan a tónico clónica generalizada (26,86 por ciento). Hubo 2 casos de status epilepticus (1,74 por ciento). En la población que presentó crisis no epiléptica predominaron los casos de migraña (62,86 por ciento); seguido por los de síncope (25,71 por ciento). La edad de la primera crisis epiléptica se presentó de 0 a 19 años en la mayoría (73,56 por ciento)

Lesiones corticales y subcorticales en 31 pacientes con sindromes afásicos / Corticals and subcorticals lesions in 31 patients with aphasic syndrom

Este estudio tuvo como fin correlacionar los tipos de síndromes afásicos diagnosticados con la aplicación del Test de Luria Adaptado y el Token Test De Renzi y A. Vignolo, con las áreas de lesion que se observan en las imágenes por tomográfia axial computarizada (TAC) en pacientes hospitalizados en las salas de Medicina Interna del Hospital Central Universitario "Antonio María Pineda" (HCUAMP). Se diseñó un estudio descriptivo transversal constituido por 31 pacientes mayores de 12 años, de ambos sexos, diestros, evaluados en la consulta externa del Servicio de Neurología entre Noviembre de 1994 y Enero de 1996. Los síndromes afásicos se clasificaron según los criterios utilizados por la Unidad de Investigación en Afasia del Hospital de Veteranos de Boston. Predominó el síndrome afásico global en 19,35 por ciento, seguido por el transcortical motor y la anomia pura, ambos con 16,12 por ciento. Por cada paciente del sexo femenino se presentaron aproximadamente 3 (2,87) pacientes del sexo masculino. La mayoría de las afasias se presentaron en pacientes entre 65 y 73 años (29,03 por ciento), predominando notablemente las lesiones corticales (83,87 por ciento) sobre las subcorticales (16,13 por ciento). El área principal de lesión cortical fue la fronto-temporal (29,03 por ciento), seguida por la parieto-occipital (16,12 por ciento). El área principal de lesión subcortical fue la talámica (16,12 por ciento). Se encontró que la isquemia fue el principal tipo de lesión (61,30 por ciento), seguido por lesiones hemorrágicas (38,7 por ciento)