Acid-Catalyzed Liquefaction of Biomasses from Poplar Clones for Short Rotation Coppice Cultivations

Liquefaction of biomass delivers a liquid bio-oil with relevant chemical and energetic applications. In this study we coupled it with short rotation coppice (SRC) intensively managed poplar cultivations aimed at biomass production while safeguarding environmental principles of soil quality and biodiversity. We carried out acid-catalyzed liquefaction, at 160 °C and atmospheric pressure, with eight poplar clones from SRC cultivations. The bio-oil yields were high, ranging between 70.7 and 81.5%. Average gains of bio-oil, by comparison of raw biomasses, in elementary carbon and hydrogen and high heating, were 25.6, 67, and 74%, respectively. Loss of oxygen and O/C ratios averaged 38 and 51%, respectively. Amounts of elementary carbon, oxygen, and hydrogen in bio-oil were 65, 26, and 8.7%, and HHV averaged 30.5 MJkg⁻¹. Correlation analysis showed the interrelation between elementary carbon with HHV in bio-oil or with oxygen loss. Overall, from 55 correlations, 21 significant and high correlations among a set of 11 variables were found. Among the most relevant ones, the percentage of elementary carbon presented five significant correlations with the percentage of O (−0.980), percentage of C gain (0.902), percentage of O loss (0.973), HHV gain (0.917), and O/C loss (0.943). The amount of carbon is directly correlated with the amount of oxygen, conversely, the decrease in oxygen content increases the elementary carbon and hydrogen concentration, which leads to an improvement in HHV. HHV gain showed a strong positive dependence on the percentage of C (0.917) and percentage of C gain (0.943), while the elementary oxygen (−0.885) and its percentage of O loss (0.978) adversely affect the HHV gain. Consequently, the O/C loss (0.970) increases the HHV positively. van Krevelen’s analysis indicated that bio-oils are chemically compatible with liquid fossil fuels. FTIR-ATR evidenced the presence of derivatives of depolymerization of lignin and cellulose in raw biomasses in bio-oil. TGA/DTG confirmed the bio-oil burning aptitude by the high average 53% mass loss of volatiles associated with lowered peaking decomposition temperatures by 100 °C than raw biomasses. Overall, this research shows the potential of bio-oil from liquefaction of SRC biomasses for the contribution of renewable energy and chemical deliverables, and thereby, to a greener global economy.

Daily cough frequency in tuberculosis and association with household infection

SETTING

Although cough in tuberculosis (TB) is presumed to be important for transmission, there is little objective supporting evidence.

OBJECTIVE

To describe 24-h cough frequency in a group with TB, and investigate associations with household rates of infection.

DESIGN

Patients with a new diagnosis of pulmonary TB underwent 24-h cough frequency measurement at or just before initiation of anti-tuberculosis treatment. A group with latent Mycobacterium tuberculosis infection (LTBI) acted as controls. Rates of infection among household contacts of sputum smear-positive TB were measured using the interferon-gamma release assay and the tuberculin skin test, and compared with variables relating to the contacts themselves, and to the index case, including cough frequency.

RESULTS

Daily cough frequency in TB patients (n = 44) was variable (geometric mean [GM] 174, interquartile range [IQR] 68-475 coughs/24 h), higher than in LTBI (n = 17; GM 19 coughs/24 h, IQR 8-53; P < 0.001), and higher during the day than overnight (GM 8.9 coughs/h, IQR 4.1-19.0 vs. GM 2.9 coughs/h, IQR 0.7-13.4; P < 0.0001). Also, 24-h cough frequency in TB was associated with sputum smear status (P = 0.040), but not smoking (P = 0.475). Multivariable logistic regression confirmed that infection in contacts was independently associated with index case sputum smear grade (P = 0.014) and cough frequency (P = 0.022).

CONCLUSION

Measurement of 24-h cough frequency in pulmonary TB helps predict infectiousness and transmission patterns.

Liquefaction of almond husk for assessment as feedstock to obtain valuable bio-oils

Almond husk liquefaction can be envisaged as an alternative to fossil sources which are becoming exhausted. Lately, the polyols obtain from the lignocellulosic biomass have been under investigation for the production of sustainable chemicals, fuel, materials or other commodities. Within this context, acid-catalyzed liquefaction of such lignocellulosic biomass has been successfully used to access highly functionalized compounds that can be used to replace those produced from petroleum. Almond shells waste can be considered to be part of the lignocellulosic biomass. Its main constituents of are cellulose, hemicellulose, and lignin. In this assay, the biochemical composition of almond husk was estimated based on atomic mass balances, and at the same time, the pyrolysis outcome was also estimated using a kinetic model using some reference compounds. In order to evaluate the use of almond waste as a substrate for acid-catalyzed liquefaction, the most favorable conditions of the liquefaction process were investigated. To better understand the liquefaction process, response surface methodology, in particular, central composite face-centered factorial design was used to set an array of 17 experiments including three replications at the center point leading to the development of a reaction model for further prediction and optimization of the liquefaction outcome. The effect of temperature (120–150 °C), time (20–200 min) and catalyst amount (0.5–5 wt. %) was investigated and a predictive model established.

Polyurethane one-component foam formulation optimization for low free isocianate monomer content

Recent changes in legislation have forced one-component foam producers to drop the amount of free monomeric isocyanate in their polyurethane systems. Also, it is required that commercial polyurethane aerosol cans exhibit at least one year of shelf life and polyurethane foams must be classified as B2 on the fire testing following DIN 4102. This paper reports on a systematic optimization study of polyurethane formulations dedicated to address these current industry requirements. A one-component foam system exhibiting simultaneously all of these parameters was achieved by reacting conventional diols, a relatively low-molecular weight monol (2-ethylhexanol), a flame retardant high-molecular weight monol (tris(bromoneopentyl)alcohol), a methylene diphenyl diisocyanate-based prepolymer (GreenAdduct 13), and a small amount of 2,4′-toluene diisocyanate. The use of monols allows producing prepolymers with low free methylene diphenyl diisocyanate by preventing chain extension and, therefore, avoiding extreme viscosity build-up. Toluene diisocyanate also promotes a lower viscosity inside the aerosol can, which enables the use of high enough quantities of high-molecular weight flame retardant monol to achieve a B2 fire test classification.

Histological and profilometric evaluation of the root surface after instrumentation with a new piezoelectric device - ex vivo study

OBJECTIVES

An ex vivo model was designed to profilometrically and histologically assess root changes resulting from scaling with a new ultrasonic device, designed for bone piezoelectric surgery, in comparison with curettes.

METHODS

Three groups of 10 periodontal hopeless teeth were each subjected to different root instrumentation: Gracey curettes (CUR); ultrasonic piezoelectric device, Perio 100% setting, level 8 (P100); and ultrasonic piezoelectric device Surg 50% setting, level 1 (S50). After extraction, all teeth were photographed to visually assess the presence of dental calculus. The treated root surfaces were profilometrically evaluated (Ra, Rz, Rmax). Undecalcified histological sections were prepared to assess qualitative changes in cementum thickness. Statistical analysis was carried out using one-way anova test with a significance level of 95%.

RESULTS

Both instruments proved to be effective in the complete removal of calculus. The CUR group presented the lowest Ra [2.28 μm (±0.58)] and S50 the highest [3.01 μm (±0.61)]. No statistically significant differences were detected among the three groups, for Ra, Rz and Rmax. Histologically, there was a cementum thickness reduction in all groups, being higher and more irregular in S50 group.

CONCLUSIONS

Within the limits of this study, there were no statistically significant differences in roughness parameters analyzed between curettes and the ultrasonic piezoelectric unit. This new instrument removes a smaller amount of cementum, mainly at the Perio 100% power setting, which appears to be the least damaging. The ultrasonic device is effective in calculus removal, proving to be as effective as curettes.

Aloe in Angola (Asphodelaceae: Alooideae). ACTA ACUST UNITED AC 2009. [DOI: 10.4102/abc.v39i1.228]

Botanical exploration of Angola was virtually impossible during the almost three-decade-long civil war. With more areas becoming accessible, there is, however, a revived interest in the flora of this country. A total of 27 members of the genus Aloe L. have been recorded for Angola. It is not unlikely that new taxa will be discovered, and that the distribution ranges of others will be expanded now that botanical exploration in Angola has resumed. This manuscript provides a complete taxonomic treatment of the known Aloe taxa in Angola. It includes, amongst other information, identification keys, descriptions and distribution maps.

The Leicester Cough Monitor: preliminary validation of an automated cough detection system in chronic cough

Chronic cough is a common condition that presents to both primary and secondary care. Assessment and management are hampered by the absence of well-validated outcome measures. The present study comprises the validation of the Leicester Cough Monitor (LCM), an automated sound-based ambulatory cough monitor. Cough frequency was measured with the LCM and compared with coughs and other sounds counted manually over 2 h of a 6-h recording by two observers in nine patients with chronic cough in order to determine the sensitivity and specificity of the LCM. Automated cough frequency was also compared with manual counts from one observer in 15 patients with chronic cough and eight healthy subjects. All subjects underwent 6-h recordings. A subgroup consisting of six control and five patients with stable chronic cough underwent repeat automated measurements > or = 3 months apart. A further 50 patients with chronic cough underwent 24-h automated cough monitoring. The LCM had a sensitivity and specificity of 91 and 99%, respectively, for detecting cough and a false-positive rate of 2.5 events x h(-1). Mean+/-SEM automated cough counts x patient x h(-1) was 48+/-9 in patients with chronic cough and 2+/-1 in the control group (mean difference 46 counts x patient x h(-1); 95% confidence interval (CI) 20-71). The automated cough counts were repeatable (intra-subject SD 11.4 coughs x patient x h(-1); intra-class correlation coefficient 0.9). The cough frequency in patients undergoing 24-h automated monitoring was 19 coughs x patient x h(-1); daytime (08:00-22:00 h) cough frequency was significantly greater than overnight cough frequency (25 versus 10 coughs x patient x h(-1); mean difference 15 coughs x patient x h(-1), 95% CI 8-22). The Leicester Cough Monitor is a valid and reliable tool that can be used to assess 24-h cough frequency in patients with cough. It should be a useful tool to assess patients with cough in clinical trials and longitudinal studies.

Novel MLH1 mutations and a novel MSH2 polymorphism identified by SSCP and DHPLC in Portuguese HNPCC families

Mismatch repair genes MSH2 and MLH1 are the two major genes implicated in hereditary nonpolyposis colorectal cancer. For the past years, we have successfully searched for mutations in both genes in affected Portuguese families, by SSCP and DNA sequencing analysis but because of the advantages that DHPLC offers, we have established conditions in our laboratory to use this new method. While screening for mutations by both methods, in 35 individuals belonging to HNPCC Portuguese families, 4 novel MLH1 mutations (c.307-1G>C; c.1023delG [p.R341fsX366]; c.2154_2155delCA [p.H718fsX721], c.2154_2155dupCA [p.I719fsX782]), an unclassified variant (c.-28A>T) and one silent MSH2 polymorphism (c.2766T>C) have been identified.

Phonomechanocardiographic findings in endomyocardial fibrosis

Endomyocardial fibrosis (EMF) is a severe restrictive cardiomyopathy characterized by the formation of fibrous tissue on the endocardium and to a lesser extent in the myocardium of one or both ventricles. The disease results in endocardial rigidity, atrioventricular valve dysfunction and progressive obliteration of the ventricular cavity. The clinical and pathological findings of EMF have been well established and definitive diagnosis can be made by selective cineangiocardiography. However, there are few reports concerning the phonomechanocardiographic (PMCG) patterns in this condition. In this paper we describe the PMCG findings in 12 patients with EMF which is now recognized with increasing frequency in the Northeast of Brazil.