40 research outputs found
Development of Structured Porous Heterogeneous Catalyst for Biodiesel Production by Transesterification of Vegetable Oil
Many environmental problems are caused when fossil fuels are used in engines. Biodiesel is a promising option to substitute these fuels because it is renewable, biodegradable and not toxic. The most used process to prepare biodiesel is by homogeneous transesterification of vegetable oils, using NaOH or KOH, but it produces a high concentration of impurities in the product. To overcome this, the use of heterogeneous catalysts is being increasingly studied. Geopolymer (GP) is an inorganic material with a chemical composition similar to zeolite and a variable microstructure, obtained by the reaction of aluminosilicates with a highly alkaline medium forming a continuous 3D network. It can be used as a heterogeneous catalyst, due to the high content of metals such as Na and/or K, as well as high basicity and specific surface area. The great advantage of using heterogeneous catalysts is that they can be recovered by filtration and reused in the process, making the biodiesel production more economical and generating fewer effluents to be treated.
This work investigated GP acting as heterogeneous catalysts to produce biodiesel by transesterification reaction of soybean oil with methanol. Three types of GP powder were produced mixing metakaolin with an activating alkaline solution: Na-based, K-based GP and a mixture between them; they were treated at 110, 300, 500 and 700 °C, then lattice-shaped GPs were designed and produced by DIW, adding PEG and filler in the previous formulation and then, they were dried at 110 °C. Porous structures with Ø ~24 mm x 9,6 mm height and unsupported parts were produced. All materials were characterized. The transesterification reaction was carried out using all the samples as a heterogeneous catalyst to evaluate the yield of biodiesel concerning the GP composition, reaction conditions and morphology of samples.
According to the results obtained in this study, it was verified that using GP both in powder and structure as catalyst, it was possible to obtain biodiesel from the transesterification of soybean oil. Comparing the materials with the same molar ratios, Na.K_GP treated at 500°C (powder) achieved the highest conversion (~98%). For the 3D structure tested in the reaction (3D_Na_GP1, 110 °C) a conversion was observed, but lower (~41%) compared to Na.K_GP, even in its powdered version (~53%). To verify the conversion efficiency of the other structures (3D_K_GP1, Na.K_GP) further studies are needed
Correlation of salivary immunoglobulin A with Body Mass Index and fat percentage in overweight/obese children
Obesity is considered a risk factor for periodontal health due to the lowgrade inflammation promoted by the increased adipose tissue. Objective: This study aimed to determine correlations and associations between gingival inflammation (Simplified Oral Hygiene Index, and Gingival Index), salivary immunoglobulin A (s-IgA), and salivary parameters (salivary flow and osmolality) in normal-weight and overweight/obese children. Material and Methods: Ninety-one children, aged 6 to 12 years old (8.6±1.9 years), were divided into two groups according to their body mass index (BMI), circumferences, skinfold measurements and body fat percentage: normalweight group (NWG; n=50) and overweight/obese group (OG; n=41). A calibrated examiner performed the clinical examination using the Simplified Oral Hygiene Index, Gingival Index, and salivary collection. Data analysis included descriptive statistics and association tests (p<0.05). Results: OG presented statistically higher s-IgA values compared with NWG, especially among the obese children (p<0.05). Significant positive correlations between s-IgA and salivary osmolality in OG (p<0.05), and between s-IgA and BMI values (p<0.05) and body fat percentage (p<0.05) were observed among all the children. Effect size varied from moderate for s-IgA values (d=0.57) to large for BMI (d=2.60). Conclusion: Gingival inflammation and salivary parameters were similar for NWG and OG; however, s-IgA presented higher values in OG, with correlations between BMI and body fat percentage
Comparison of salivary cytokines levels among individuals with Down syndrome, cerebral palsy and normoactive
Individuals with Down syndrome (DS) present increased susceptibility to infections and high prevalence of periodontal disease. The objective of this study is to evaluate the salivary concentrations of IL-1?, IL-6, IL-8, IL-10, TNF? and IL-12p70 of DS individuals and compare to cerebral palsy (CP) and normoactive patients (all with gingivitis). Twenty-two individuals with DS, 24 with CP and 22 normoactive participated in this cross-sectional study. Salivary flow rate, osmolality rate, Oral Hygiene Index, Gingival Index (GI) and salivary inflammatory markers IL-1?, IL-6, IL-8, IL-10, TNF? and IL-12p70 were evaluated. Shapiro-Wilks, Chi-square, ANOVA One-Way and Kruskal Wallis tests were applied with significance level at 5%. The groups were homogenous for gender, age, and IL12p70 cytokine (p>0.05). GI was significantly higher in DS compared to CP and healthy (p<0.05). CP presented reduced salivary flow and increased osmolality rate. CP showed significantly higher values for TNF?, IL10, and IL6 compared to DS and normoactive (p<0.05). DS and CP presented significantly higher values of IL-1? and IL8 compared to normoactive (p<0.05). Individuals with CP have higher risk to develop periodontal disease due to reduced salivary flow rate, increased salivary osmolality rate and elevated TNF?, IL-10, IL-6 compared to DS
Biodiesel Processing Using Sodium and Potassium Geopolymer Powders as Heterogeneous Catalysts
This work investigates the catalytic activity of geopolymers produced using two different alkali components (sodium or potassium) and four treatment temperatures (110 to 700 \ub0C) for the methyl transesterification of soybean oil. The geopolymers were prepared with metakaolin as an aluminosilicate source and alkaline activating solutions containing either sodium or potassium in the same molar oxide proportions. The potassium-based formulation displayed a higher specific surface area and lower average pore size (28.64-62.54 m\ub2/g; 9 nm) than the sodium formulation (6.34-32.62 m\ub2/g; 17 nm). The reduction in specific surface area (SSA) after the heat treatment was more severe for the sodium formulation due to the higher thermal shrinkage. The catalytic activity of the geopolymer powders was compared under the same reactional conditions (70-75 \ub0C, 150% methanol excess, 4 h reaction) and same weight amounts (3% to oil). The differences in performance were attributed to the influences of sodium and potassium on the geopolymerization process and to the accessibility of the reactants to the catalytic sites. The Na-based geopolymers performed better, with FAME contents in the biodiesel phase of 85.1% and 89.9% for samples treated at 500 and 300 \ub0C, respectively. These results are competitive in comparison with most heterogeneous base catalysts reported in the literature, considering the very mild conditions of temperature, excess methanol and catalyst amount and the short time spent in reactions
Effects of treatments for drooling on caries risk in children and adolescents with cerebral palsy
Neuromuscular impairment makes individuals with cerebral palsy (CP) more prone to drooling. Among the treatment options, there are procedures that interfere with saliva production. It is imperative to evaluate the effect of the different modalities since the reduction in salivary flow rate/production may exacerbate the risk of dental caries. The aim of this study was to compare the effects of different treatments for drooling on caries risk and salivary parameters in children and adolescents with CP. A total of 142 children and adolescents with CP, aged 6 to 18 years, were assigned to groups based on the different treatments they had received for drooling: G1?anticholinergic drugs (n = 18), G2?botulinum toxin injection (n = 16), G3?salivary glands surgery (n = 16), G4?no treatment (n = 42), and G5?non-drooling subjects (n = 50). All participants were evaluated on the Simplified Oral Hygiene Index, and for the prevalence of dental caries (decayed, missing, and filled teeth index and white spot lesions). Unstimulated whole saliva was collected, and salivary flow rate and osmolality were measured. Chi-square, ANOVA and Poisson regression were calculated. Prevalence ratios and their respective 95 % confidence intervals were obtained. The significance level was fixed at 5%. No differences were found in the decayed, missing, and filled teeth index (p = 0.128) and Simplified Oral Hygiene Index (p = 0.674) among the different groups. G3 presented significantly higher percentages of WSL (p<0.001), lower values of salivary flow rate (p<0.001), and higher values of osmolality (p<0.001). The white spot lesion prevalence ratio was higher only for G3 (Prevalence ratio = 14.36; IC 95% = 4.64-44.40; p<0.001). Children and adolescents with CP who had received surgical treatment for drooling exhibited higher number of white spot lesions because of the reduced salivary flow rate and higher salivary osmolality
Acceptability of the 6-PACK falls prevention program: A pre-implementation study in hospitals participating in a cluster randomized controlled trial
There is limited evidence to support the effectiveness of falls prevention interventions in the acute hospital setting. The 6-PACK falls prevention program includes a fall-risk tool; 'falls alert' signs; supervision of patients in the bathroom; ensuring patients' walking AIDS are within reach; toileting regimes; low-low beds; and bed/chair alarms. This study explored the acceptability of the 6-PACK program from the perspective of nurses and senior staff prior to its implementation in a randomised controlled trial. A mixed-methods approach was applied involving 24 acute wards from six Australian hospitals. Participants were nurses working on participating wards and senior hospital staff including: Nurse Unit Managers; senior physicians; Directors of Nursing; and senior personnel involved in quality and safety or falls prevention. Information on program acceptability (suitability, practicality and benefits) was obtained by surveys, focus groups and interviews. Survey data were analysed descriptively, and focus group and interview data thematically. The survey response rate was 60%. Twelve focus groups (n = 96 nurses) and 24 interviews with senior staff were conducted. Falls were identified as a priority patient safety issue and nurses as key players in falls prevention. The 6-PACK program was perceived to offer practical benefits compared to current practice. Nurses agreed fall-risk tools, low-low beds and alert signs were useful for preventing falls (>70%). Views were mixed regarding positioning patients' walking aid within reach. Practical issues raised included access to equipment; and risk of staff injury with low-low bed use. Bathroom supervision was seen to be beneficial, however not always practical. Views on the program appropriateness and benefits were consistent across nurses and senior staff. Staff perceived the 6-PACK program as suitable, practical and beneficial, and were open to adopting the program. Some practical concerns were raised highlighting issues to be addressed by the implementation plan
Barriers and enablers to the implementation of the 6-PACK falls prevention program: A preimplementation study in hospitals participating in a cluster randomised controlled trial
Evidence for effective falls prevention interventions in acute wards is limited. One reason for this may be suboptimal program implementation. This study aimed to identify perceived barriers and enablers of the implementation of the 6-PACK falls prevention program to inform the implementation in a randomised controlled trial. Strategies to optimise successful implementation of 6-PACK were also sought. A mixed-methods approach was applied in 24 acute wards from 6 Australian hospitals. Participants were nurses working on participating wards and senior hospital staff including Nurse Unit Managers; senior physicians; Directors of Nursing; and senior personnel involved in quality and safety or falls prevention. Information on barriers and enablers of 6-PACK implementation was obtained through surveys, focus groups and interviews. Questions reflected the COM-B framework that includes three behaviour change constructs of: capability, opportunity and motivation. Focus group and interview data were analysed thematically, and survey data descriptively. The survey response rate was 60% (420/702), and 12 focus groups (n = 96 nurses) and 24 interviews with senior staff were conducted. Capability barriers included beliefs that falls could not be prevented; and limited knowledge on falls prevention in patients with complex care needs (e.g. cognitive impairment). Capability enablers included education and training, particularly face to face case study based approaches. Lack of resources was identified as an opportunity barrier. Leadership, champions and using data to drive practice change were recognised as opportunity enablers. Motivation barriers included complacency and lack of ownership in falls prevention efforts. Motivation enablers included senior staff articulating clear goals and a commitment to falls prevention; and use of reminders, audits and feedback. The information gained from this study suggests that regular practical face-to-face education and training for nurses; provision of equipment; audit, reminders and feedback; leadership and champions; and the provision of falls data is key to successful falls prevention program implementation in acute hospitals
Prevalence of oral manifestations in soft tissues during early childhood in Brazilian children
Development of Structured Porous Heterogeneous Catalyst for Biodiesel Production by Transesterification of Vegetable Oil
Many environmental problems are caused when fossil fuels are used in engines. Biodiesel is a promising option to substitute these fuels because it is renewable, biodegradable and not toxic. The most used process to prepare biodiesel is by homogeneous transesterification of vegetable oils, using NaOH or KOH, but it produces a high concentration of impurities in the product. To overcome this, the use of heterogeneous catalysts is being increasingly studied. Geopolymer (GP) is an inorganic material with a chemical composition similar to zeolite and a variable microstructure, obtained by the reaction of aluminosilicates with a highly alkaline medium forming a continuous 3D network. It can be used as a heterogeneous catalyst, due to the high content of metals such as Na and/or K, as well as high basicity and specific surface area. The great advantage of using heterogeneous catalysts is that they can be recovered by filtration and reused in the process, making the biodiesel production more economical and generating fewer effluents to be treated.
This work investigated GP acting as heterogeneous catalysts to produce biodiesel by transesterification reaction of soybean oil with methanol. Three types of GP powder were produced mixing metakaolin with an activating alkaline solution: Na-based, K-based GP and a mixture between them; they were treated at 110, 300, 500 and 700 °C, then lattice-shaped GPs were designed and produced by DIW, adding PEG and filler in the previous formulation and then, they were dried at 110 °C. Porous structures with Ø ~24 mm x 9,6 mm height and unsupported parts were produced. All materials were characterized. The transesterification reaction was carried out using all the samples as a heterogeneous catalyst to evaluate the yield of biodiesel concerning the GP composition, reaction conditions and morphology of samples.
According to the results obtained in this study, it was verified that using GP both in powder and structure as catalyst, it was possible to obtain biodiesel from the transesterification of soybean oil. Comparing the materials with the same molar ratios, Na.K_GP treated at 500°C (powder) achieved the highest conversion (~98%). For the 3D structure tested in the reaction (3D_Na_GP1, 110 °C) a conversion was observed, but lower (~41%) compared to Na.K_GP, even in its powdered version (~53%). To verify the conversion efficiency of the other structures (3D_K_GP1, Na.K_GP) further studies are needed.Molti problemi ambientali sono causati dall'uso dei combustibili fossili nei motori. Il biodiesel è un'opzione promettente per sostituire questi carburanti perché è rinnovabile, biodegradabile e non tossico. Il processo più utilizzato per preparare il biodiesel è la transesterificazione omogenea degli oli vegetali, utilizzando NaOH o KOH, ma produce un'alta concentrazione di impurità nel prodotto. Per superare questo, l'uso di catalizzatori eterogenei viene sempre più studiato. Geopolymer (GP) è un materiale inorganico con una composizione chimica simile alla zeolite e una microstruttura variabile, ottenuta dalla reazione di alluminosilicati con un mezzo altamente alcalino che forma una rete 3D continua. Può essere usato come catalizzatore eterogeneo, a causa dell'elevato contenuto di metalli come Na e/o K, nonché di un'elevata basicità e di una superficie specifica. Il grande vantaggio dell'utilizzo di catalizzatori eterogenei è che possono essere recuperati mediante filtrazione e riutilizzati nel processo, rendendo la produzione di biodiesel più economica e generando meno effluenti da trattare.
Questo lavoro ha indagato su GP che agisce come catalizzatori eterogenei per produrre biodiesel mediante la reazione di transesterificazione dell'olio di soia con metanolo. Sono stati prodotti tre tipi di polvere GP miscelando metacaolino con una soluzione alcalina attivante: GP a base di Na, a base di K e una miscela tra loro; sono stati trattati a 110, 300, 500 e 700 °C, quindi i GP a forma di reticolo sono stati progettati e prodotti da DIW, aggiungendo PEG e filler nella precedente formulazione e quindi, sono stati essiccati a 110 °C. Sono state prodotte strutture porose con Ø ~ 24 mm x 9,6 mm di altezza e parti non supportate. Tutti i materiali sono stati caratterizzati. La reazione di transesterificazione è stata effettuata utilizzando tutti i campioni come catalizzatore eterogeneo per valutare la resa di biodiesel riguardante la composizione GP, le condizioni di reazione e la morfologia dei campioni.
In base ai risultati ottenuti in questo studio, è stato verificato che l'utilizzo di GP sia in polvere sia nella struttura come catalizzatore, è stato possibile ottenere biodiesel dalla transesterificazione dell'olio di soia. Confrontando i materiali con gli stessi rapporti molari, Na.K_GP trattato a 500 °C (polvere) ha ottenuto la conversione più alta (~98%). Per la struttura 3D testata nella reazione (3D_Na_GP1, 110 °C) è stata osservata una conversione, ma inferiore (~41%) rispetto a Na.K_GP, anche nella sua versione in polvere (~53%). Per verificare l'efficienza di conversione delle altre strutture (3D_K_GP1, Na.K_GP) sono necessari ulteriori studi