ABSTRACT
The present work intends to study the variations in the rheological properties and aggregation behaviour of TEMPO-oxidised cellulose nanofibrils (CNF) aqueous suspensions, as a function of changes in concentration and systematic changes in the pH, by addition of acids with different anions. It was found that CNF suspensions form strong gels at mass fractions higher than 0.35 % and the gel point is ca. 0.18 %. On the other hand, aggregation is enhanced at acidic pH conditions due to lower charge repulsion among fibrils, leading to an increase of the suspension viscosity. However, distinct rheological behaviours were presented by CNF suspensions as different acids were applied. It was found that phosphate ions resulted in significant aggregation leading to formation of particles of large size and very strong gels, at pH 2.3; distinctly, the presence of acetate ions resulted in lower aggregation, lower particle size and weaker gels, at the same pH value.
ABSTRACT
This work aimed to study the influence of the initial chemical composition (glucans, lignin, xylan, and mannans), intrinsic viscosity, and carboxylate groups of pulps on the production process and final properties of lignocellulosic nanofibers (LCNF). Pulps of pine sawdust, eucalyptus sawdust, and sugarcane bagasse subjected to conventional pulping and highly oxidized processes were the starting materials. The LCNF were obtained by TEMPO mediated oxidation and mechanical fibrillation with a colloidal grinder. The nanofibrillation degree, chemical charge content, rheology, laser profilometry, cristallinity and atomic force microscopy were used to characterize the LCNF. The carboxylate groups, hemicelluloses and lignin of the initial pulps were important factors that affected the production process of LCNF. The results revealed that intrinsic viscosity and carboxylate groups of the initial pulps affected LCNF production process, whereas lignin and hemicelluloses influenced the viscosity of LCNF aqueous suspensions, the roughness of LCNF films, and the carboxylate groups content of LCNF.
Subject(s)
Lignin/chemistry , Nanofibers/chemistry , Pinus/chemistry , Oxidation-ReductionABSTRACT
The Ponseti method of treating club foot has been shown to be effective in children up to two years of age. However, it is not known whether it is successful in older children. We retrospectively reviewed 17 children (24 feet) with congenital idiopathic club foot who presented after walking age and had undergone no previous treatment. All were treated by the method described by Ponseti, with minor modifications. The mean age at presentation was 3.9 years (1.2 to 9.0) and the mean follow-up was for 3.1 years (2.1 to 5.6). The mean time of immobilisation in a cast was 3.9 months (1.5 to 6.0). A painless plantigrade foot was obtained in 16 feet without the need for extensive soft-tissue release and/or bony procedures. Four patients (7 feet) had recurrent equinus which required a second tenotomy. Failure was observed in five patients (8 feet) who required a posterior release for full correction of the equinus deformity. We conclude that the Ponseti method is a safe, effective and low-cost treatment for neglected idiopathic club foot presenting after walking age.
Subject(s)
Clubfoot/surgery , Orthopedic Procedures/methods , Achilles Tendon/surgery , Calcaneus/pathology , Casts, Surgical , Child , Child, Preschool , Clubfoot/pathology , Clubfoot/physiopathology , Equinus Deformity/surgery , Female , Foot/pathology , Foot/surgery , Humans , Infant , Male , Postoperative Complications , Range of Motion, Articular/physiology , Reoperation , Retrospective Studies , Talus/pathology , Time Factors , Treatment OutcomeABSTRACT
The National Consense abot Spasticity by Brazilian Society of Physical Medicine and Rehabilitation (SBMFR) and Brazilian Medical Association (AMB) was done based on critical analysis of epidemiological studies, showing that traditional terapeutic resources need more studies for posterior approving
Subject(s)
Muscle SpasticityABSTRACT
Forefoot adduction is the most common residual deformity after clubfoot surgery. Surgical treatment of this deformity is often required for moderate and severe cases. This study reports the results of a closing wedge osteotomy of the cuboid and opening wedge osteotomy of the medial cuneiform in 39 feet. The average follow-up was 4.8 years. Clinical and radiographic improvement was seen in all patients, and no complications were seen. Surgery is advocated in children older than age 4, or when the medial cuneiform ossific nucleus is well developed.
Subject(s)
Clubfoot/surgery , Osteotomy/methods , Tarsal Bones/surgery , Child , Child, Preschool , Clubfoot/diagnostic imaging , Female , Humans , Male , Radiography , Reoperation , Tarsal Bones/diagnostic imaging , Treatment OutcomeABSTRACT
A via de acesso de Cincinnati foi utilizada em 111 pacientes (164 pés) portadores de pé torto eqüinovaro congênito (PTC) no período de 1985 a 1994. Os autores descrevem a técnica cirúrgica empregada e as facilidades que envolvem a abordagem das regiöes medial, posterior e lateral através dessa via de acesso. Os resultados säo analisados por um sistema de avaliaçäo funcional que permite, por meio de exame clínico e radiográfico, classificá-los em excelentes, bons, regulares e ruins. Os autores, entretanto, sugerem que os resultados excelentes e bons sejam denominados satisfatórios e os regulares e ruins, insatisfatórios. A análise comparativa entre duas faixas etárias é submetida ao estudo estatístico. Dessa forma, foi possível concluir que a idade influenciou significantemente os resultados obtidos.
