Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

Estudos da produção de bioetanol usando biomassa de pinhão manso, um co-produto do processo produtivo de biodiesel

Este trabalho apresenta resultados do estudo relacionado à produção de etanol a partir de fontes lignocelulósicas, em particular, de resíduos do processo de produção de biodiesel. Dados da composição química de diversas fontes lignocelulósicas foram analisados e os resíduos de palma e pinhão-manso foram os que mostraram maior potencial para produção de etanol celulósico, com produtividade igual a 6725 L/ha e 695 L/ha respectivamente. A viabilidade técnica da produção de etanol a partir da torta de pinhão manso por hidrólise enzimática foi avaliada. A torta de pinhão-manso foi submetida à hidrólise enzimática (30 FPU/g de biomassa com excesso de celobiase), utilizando-se três tipos de pré-tratamento (0,2% H2SO4, 1,0% NaOH e 1,5% Ca(OH)2) por uma hora a 121°C. As concentrações de açúcar foram medidas por cromatografia liquida de alta eficiência (HPLC) e comparadas com os resultados de concentração dos açúcares redutores determinados pelo método de ácido dinitrossalicílico (DNS). Após 24 h, as concentrações total de glicose e xilose avaliadas por HPLC foram de 3,33, 4,82, 5,80, e 5,55 g/L sem pré-tratamento ou com pré-tratamentos com H2SO4, NaOH, e Ca(OH)2, respectivamente. As concentrações de açúcares redutores foram de 7,30, 11,95, 10,24, e 9,34 g/L para as mesmas condições de tratamento, portanto, aproximadamente 100% maiores do que os valores obtidos por HPLC. Visando a produção direta de etanol, utilizou-se 20 g de casca de pinhão-manso pré-tratada para a etapa de sacarificação e fermentação simultâneas (SSF). Para tal, condições de prétratamentos (0,5% H2SO4 ou 1,0% NaOH, ambos a 121°C por 1 h), teor de matéria inibidora solúvel (lavados ou não- lavados após pré-tratamento) e concentração de enzimas (15 FPU de celulase/g de biomassa com ou sem um adicional de 4 U de xilanases/g de biomassa) foram utilizados, enquanto a inoculação de leveduras (0,80 g de células secas de Saccharomyces cerevisiae/L) foi mantida constante. Após 48h, as concentrações de etanol foram maiores nas amostras submetidas ao pré-tratamento alcalino (Etanol > 7,0 g/L). A adição de xilanases não teve efeito na elevação da concentração de etanol e na produção de xilose. Para as amostras submetidas ao pré-tratamento ácido, a mistura não-lavada apresentou concentrações de etanol inferiores às misturas lavadas (5,39 g/L a 6,07 g/L), porém nas amostras submetidas ao pré-tratamento com NaOH, não houve diferença significativa encontrada entre as amostras lavadas e não-lavadas.Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorThis work presents data and studies related to the production of bioethanol from lignocellulosic sources, in particular, coproducts from the biodiesel production process. Chemical composition data from soybean, castor bean, Jatropha curcas, palm kernel, sunflower seed, rapeseed and cottonseed were gathered and palm kernel and Jatropha showed the greatest potentials for cellulose ethanol production with values of 6725 L/ha and 695 L/ha, respectively. The technical feasibility of ethanol production from Jatropha meal via enzymatic hydrolysis was evaluated. Jatropha meal was subjected to enzymatic hydrolysis (30 FPU/g of biomass and an excess of cellobiase), using three types of chemical pretreatments (0.2% H2SO4, 1.0% NaOH and 1.5% Ca(OH)2) for 1 h at 121°C. Sugar concentrations were measured by HPLC and compared with results for reducing sugars measured using the dinitrosalicylic acid (DNS) method. After 24 h, the total concentrations of glucose and xylose measured by HPCL were 3.33, 4.82, 5.80 and 5.55 g/L for the untreated, H2SO4, NaOH, and Ca(OH)2 pretreatments, respectively. In comparison, reducing sugar concentrations were nearly 100% greater showing values of 7.30, 11.95, 10.24 and 9.34 g/L for the same pretreatments. Simultaneous saccharification and fermentation (SSF) was performed on 20 g of pretreated Jatropha shells for the more consolidated production of ethanol. Pretreatment type (0.5% H2SO4 and 1.0 % NaOH at 121°C for 1 h), water insoluble solids (WIS) (washed or unwashed after pretreatment) and enzyme loading (15 FPU/g biomass of cellulase with or without an additional 4 U/g biomass of xylanase enzymes) were considered while yeast loading (0.80 g/L dry Saccharomyces cerevisiae cells) was kept constant. After 48 h, ethanol concentrations were highest in the alkaline pretreated samples (> 7.0 g/L). The addition of xylanase enzymes had no significant effect on ethanol concentration or xylose production. For the acid pretreated samples, the unwashed slurry showed ethanol concentrations inferior to those of the washed sample (5.39 g/L to 6.07 g/L), but in the NaOH pretreated samples, no significant difference was verified between washed and unwashed

A produção de bioetanol utilizando enzimas fúngicas hidrolíticas e diferentes métodos de processamento

A produção em escala industrial de bioetanol a partir de fontes lignocelulósicas ainda está em suas fases iniciais, principalmente devido aos altos custos de processamento e, mais especificamente, aos custos elevados de complexos enzimáticos comerciais. No processamento de cana convencional, cerca de 50% do bagaço é queimado para produção de calor, no entanto, quando se considera a conversão de bagaço para etanol, 55% do bagaço pode ser processado para a produção de etanol de segunda geração, enquanto os outros 45% de bagaço fresco e lignina resultantes da hidrólise enzimática são suficientes para alimentar a usina de etanol convencional e também fornecer energia para o processamento/destilação de etanol derivado de lignocelulose. A levedura geneticamente modificada S. cerevisiae YRH400 mostrou-se mais eficiente para fermentação de glicose e xilose em etanol do que K. marxianus ATCC-8554 e K. marxianus UFV-3. A hidrólise enzimática foi realizada em bagaço de cana, inicialmente submetido ao pré-tratamento alcalino, usando um extrato de enzima obtida a partir de Chrysoporthe cubensis, produzida pela fermentação em estado sólido. As condições de hidrólise foram temperatura de 50°C e concentração de sólidos de 7.5% (m/v). Este resultado foi comparado a hidrólise e fermentação híbrido (48 e 12 horas de préhidrólise), utilizando as leveduras S. cerevisiae YRH400 e K. marxianus ATCC-8554 sob temperaturas de fermentação de 30 e 40 °C, respectivamente. Hidrólise e fermentação separados pareceu ser mais eficiente, conseguindo converter glicose e xilose com eficiência de 45 e 97%, respectivamente, no caso de utilização de uma carga enzimática de 10 FPU/g de biomassa pré-tratada, durante um período de 120 horas de hidrólise. Uma combinação de extratos enzimáticos apresentando atividades complementares foi realizada para se obter um complexo enzimático mais completo. Estudos anteriores indicaram que Chrysoporthe cubensis é um bom produtor de b-glicosidase, xilanase e outras enzimas acessórias, enquanto que o extrato de Penicillium pinophilum é rico em celulases (FPases, endoglucanases e celobiohidrolases). O sinergismo máximo foi observado, entre estes dois extratos, quando misturado na proporção de 50:50, apresentando valores de sinergismo de 76%, 50% e 24% para as atividades de FPase, endoglucanase e xilanase, respectivamente. Este extrato enzimático misturado foi então aplicado na hidrólise do bagaço de cana, submetido a um processo de pré-tratamento alcalino com diferentes cargas enzimáticas e concentrações de biomassa a 45 °C. A conversãoF máxima de glicose e xilose (64% e 93%, respectivamente) foi obtida para o tratamento com a carga enzimática de 20 FPU/g e concentração de sólidos de 8%. Um outro ensaio foi realizado utilizando uma temperatura de reação de 50 °C. À temperatura mais alta, foram obtidos aumentos de 16% e 20% em relação às conversões para glicose e xilose, respectivamente. Além disso, para o tratamento realizado à 50 °C, a taxa de hidrólise foi quase constante após 120 horas, enquanto a taxa de hidrólise dos dois ensaios realizados a 45 °C diminuíram significativamente (0.14 g/l/h at 50°C and 0.10 g/l/h at 45 °C). Neste último experimento, a hidrólise enzimática foi realizada à 50 °C após períodos predeterminados de tempo, a fração sólida foi reciclada na tentativa de reciclar enzimas aderidas à biomassa sólida. Verificou-se que, quando se adiciona 1x (o mesmo valor), 1/2x ou nenhuma enzima durante o segundo período de hidrólise, a mesma quantidade de glicose foi produzida, indicando que as enzimas foram eficientemente recicladas. No entanto, quando adicionado a mesma quantidade de biomassa (8 ou 12% m/v), durante cada período de reciclagem, a concentração de sólidos aumentou e diminuiu significativamente a eficiência de hidrólise. No caso em que a hidrólise foi monitorada continuamente e a concentração de sólidos foi mantida constante (12%), a eficiência da hidrólise de biomassa fresca adicionada a cada ciclo de reciclagem aumentou continuamente, indicando que as celulases e hemicelulases foram eficientemente recicladas e que a lignina não teve nenhum efeito indesejável sobre a hidrólise enzimática.Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorIndustrial-scale production of bioethanol from lignocellulosic sources is still in its initial phases, mainly due to the high processing costs and more specifically the high costs of commercial enzyme complexes. In conventional sugarcane processing, roughly 50% of bagasse is combusted to power the facility; however when considering the conversion of bagasse to bioethanol, 55% of bagasse can be processed for second generation ethanol production while the other 45% of fresh bagasse and lignin resulting from enzymatic hydrolysis is sufficient to power the conventional ethanol plant and also provide energy for processing/distillation of lignocellulose derived ethanol. The genetically modified yeast strain S. cerevisiae YRH400 showed to be more efficient for fermenting of both glucose and xylose to ethanol than K. marxianus ATCC-8554 and K. marxianus UFV-3. Enzymatic hydrolysis was performed on alkali-pretreated sugarcane bagasse using an enzyme extract obtained from Chrysoporthe cubensis produced via solid-state fermentation at the optimal temperature of 50°C with solids loading of 7.5%. This was compared with hybrid hydrolysis and fermentation (48 and 12 hour prehydrolysis periods) using the yeasts S. cerevisiae YRH400 and K. marxianus ATCC- 8554 at the fermentation temperatures of 30°C and 40°C, respectively. Separate hydrolysis and fermentation appeared to be the most efficient, achieving glucose and xylose conversion efficiencies of 45 and 97%, respectively, for the enzyme loading of 10 FPU/g pretreated biomass over a 120 hour hydrolysis period. Blending of enzyme extracts with complementing activities was performed to obtain a more complete enzyme complex. Previous studies indicated that Chrysoporthe cubensis is a good producer of b-glucosidase, xylanase and other accessory enzymes, while the extract from Penicillium pinophilum is rich in cellulases (FPase, endoglucanases and cellobiohydrolases). Maximum synergy was observed between these two extracts when blended at the concentration of 50:50, presenting synergism values of 76%, 50% and 24% for FPase, endoglucanase and xylanase activities, respectively. This blended enzyme extract was then applied for hydrolysis of alkali-pretreated sugarcane bagasse at different enzyme and biomass loadings at 45°C. A maximum conversion of glucose and xylose (64% and 93%, respectively) was obtained for the treatment with enzyme loading of 20 FPU/g and solids loading of 8%. Another assay was performed utilizing a reaction temperature of 50°C. At the higher temperature increases of 16% and 20% were obtained with respect to the glucose and xylose conversions, respectively. Moreover, for the treatment performed at 50°C the hydrolysis rate was nearly constant after 120 hours while those of the assays performed at 45°C showed to decrease more significantly. In this last experiment enzymatic hydrolysis was performed at 50°C and after predetermined time periods the solid fraction was recycled in an attempt to recycle enzymes adhered to the solid biomass. It was found that when adding the 1x (the same amount), 1/2x or no additional enzyme in the second hydrolysis period the same amount of glucose was produced, indicating the enzymes were efficiently recycled. However when adding the same amount of biomass (8 or 12%) during each recycle period the solids concentration increased and hydrolysis efficiency decreased significantly. In the experiment in which hydrolysis was continuously monitored and the solids concentration maintained constant (12%), hydrolysis efficiency of the fresh biomass added continuously increased, indicating that cellulase and hemicellulase enzymes were efficiently recycled and that lignin had no negative effect on enzymatic hydrolysis

Bioethanol production potential from brazilian biodiesel co-products

One major problem facing the commercial production of cellulosic ethanol is the challenge of economically harvesting and transporting sufficient amounts of biomass as a feedstock at biorefinery plant scales. Oil extraction for biodiesel production, however, yields large quantities of biomass co-products rich in cellulose, sugar and starch, which in many cases may be sufficient to produce enough ethanol to meet the alcohol demands of the transesterification process. Soybean, castor bean, Jatropha curcas, palm kernel, sunflower and cottonseed were studied to determine ethanol production potential from cellulose found in the oil extraction co-products and also their capacity to meet transesterification alcohol demands. All crops studied were capable of producing enough ethanol for biodiesel production and, in the case of cottonseed, 470% of the transesterification demand could be met with cellulosic ethanol production from oil extraction co-products. Based on Brazilian yields of the crops studied, palm biomass has the highest potential ethanol yield of 108 m^3 km^−2 followed by J. curcas with 40 m^3 km^−2. A total of 3.5 hm^3 could be produced from Brazilian soybean oil extraction co-products

Increased enzymatic hydrolysis of sugarcane bagasse from enzyme recycling

Development of efficient methods for production of renewable fuels from lignocellulosic biomass is necessary to maximize yields and reduce operating costs. One of the main challenges to industrial application of the lignocellulosic conversion process is the high costs of cellulolytic enzymes. Recycling of enzymes may present a potential solution to alleviate this problem. In the present study enzymes associated with the insoluble fraction were recycled after enzymatic hydrolysis of pretreated sugarcane bagasse, utilizing different processing conditions, enzyme loadings, and solid loadings. It was found that the enzyme blend from Chrysoporthe cubensis and Penicillium pinophilum was efficient for enzymatic hydrolysis and that a significant portion of enzyme activity could be recovered upon recycling of the insoluble fraction. Enzyme productivity values (g glucose/mg enzyme protein) over all recycle periods were 2.4 and 3.7 for application of 15 and 30 FPU/g of glucan, representing an increase in excess of ten times that obtained in a batch process with the same enzyme blend and an even greater increase compared to commercial cellulase enzymes. Contrary to what may be expected, increasing lignin concentrations throughout the recycle period did not negatively influence hydrolysis efficiency, but conversion efficiencies continuously improved. Recycling of the entire insoluble solids fraction was sufficient for recycling of adhered enzymes together with biomass, indicative of an effective method to increase enzyme productivity

Simultaneous saccharification and fermentation (SSF) of Jatropha curcas shells: utilization of co-products from the biodiesel production process

Jatropha curcas has great potential as an oil crop for use in biodiesel applications, and the outer shell is rich in lignocellulose that may be converted to ethanol, giving rise to the concept of a biorefinery. In this study, two dilute pretreatments of 0.5% H2SO4 and 1.0% NaOH were performed on Jatropha shells with subsequent simultaneous saccharification and fermentation (SSF) of the pretreated water-insoluble solids (WIS) to evaluate the effect of inhibitors in the pretreatment slurry. A cellulase loading of 15 FPU/g WIS, complimented with an excess of cellobiase (19.25 U/g), was used for SSF of either the washed WIS or the original slurry to determine the effect of inhibitors. Ethanol and glucose were monitored during SSF of 20 g of pretreated biomass. The unwashed slurry showed to have a positive effect on SSF efficiency for the NaOH-pretreated biomass. Maximum efficiencies of glucan conversion to ethanol in the WIS were 40.43% and 41.03% for the H2SO4- and NaOH-pretreated biomasses, respectively

The influence of pretreatment methods on saccharification of sugarcane bagasse by an enzyme extract from Chrysoporthe cubensis and commercial cocktails : A comparative study

Biomass enzymatic hydrolysis depends on the pretreatment methods employed, the composition of initial feedstock and the enzyme cocktail used to release sugars for subsequent fermentation into ethanol. In this study, sugarcane bagasse was pretreated with 1% H2SO4 and 1% NaOH and the biomass saccharification was performed with 8% solids loading using 10 FPase units/g of bagasse of the enzymatic extract from Chrysoporthe cubensis and three commercial cocktails for a comparative study. Overall, the best glucose and xylose release was obtained from alkaline pretreated sugarcane bagasse. The C. cubensis extract promoted higher release of glucose (5.32g/L) and xylose (9.00g/L) than the commercial mixtures. Moreover, the C. cubensis extract presented high specific enzyme activities when compared to commercial cocktails mainly concerning to endoglucanase (331.84U/mg of protein), β-glucosidase (29.48U/mg of protein), β-xylosidase (2.95U/mg of protein), pectinase (127.46U/mg of protein) and laccase (2.49U/mg of protein)

The influence of pretreatment methods on saccharification of sugarcane bagasse by an enzyme extract from Chrysoporthe cubensis and commercial cocktails: A comparative study

Biomass enzymatic hydrolysis depends on the pretreatment methods employed, the composition of initial feedstock and the enzyme cocktail used to release sugars for subsequent fermentation into ethanol. In this study, sugarcane bagasse was pretreated with 1% H2SO4 and 1% NaOH and the biomass saccharification was performed with 8% solids loading using 10 FPase units/g of bagasse of the enzymatic extract from Chrysoporthe cubensis and three commercial cocktails for a comparative study. Overall, the best glucose and xylose release was obtained from alkaline pretreated sugarcane bagasse. The C. cubensis extract promoted higher release of glucose (5.32g/L) and xylose (9.00g/L) than the commercial mixtures. Moreover, the C. cubensis extract presented high specific enzyme activities when compared to commercial cocktails mainly concerning to endoglucanase (331.84U/mg of protein), β-glucosidase (29.48U/mg of protein), β-xylosidase (2.95U/mg of protein), pectinase (127.46U/mg of protein) and laccase (2.49U/mg of protein)