Mechanical properties of chemically modified portuguese pinewood

To turn wood into a construction material with enhanced properties, many methods of chemical modification have been developed in the last few decades. In this work, mechanical properties of pine wood were chemically modified, compared and evaluated. Maritime pine wood (Pinus pinaster) was modified with four chemical processes: 1,3-dimethylol-4,5- dihydroxyethyleneurea, N-methylol melamine formaldehyde, tetra-alkoxysilane and wax. The following mechanical properties were assessed experimentally: Modulus of elasticity measured statically, stiffness stabilization efficiency in different climates (30 and 87% of relative humidity), modulus of rupture, work maximum load, impact bending strength, compression, tensile and shear strength at indoor conditions (65% of relative humidity). In both types of active principle of modification, cell wall or lumen fill, no significant changes on the bending stiffness (modulus of elasticity) were found. In the remaining properties analysed significant changes in the modified wood-material took place compared to unmodified wood control: - Cell wall modification was the most effective method to achieve high stiffness stabilization efficiency (up to 60%) and also increased compression strength (up to 230%). However, modulus of rupture, tensile, shear and the impact bending strength were reduced by both resins, but in a varying extent, where the N-methylol melamine formaldehyde endured less reduction than 1,3-dimethylol-4,5-dihydroxyethyleneurea resin. In the latter, reduction up to 60% can take place. - In the lumen fill modification: tetra-alkoxysilane has no effect in the mechanical properties. Although, a slight increase in shear strength parallel to the grain was found. Wax specimens have shown a slight increase in bending strength, compression, tensile and shear strength as well as in the absorption energy capacity.

Plant derived and dietary phenolic antioxidants: Anticancer properties

n this paper, a review of the literature on the phenolic compounds with anticancer activity published between 2008 and 2012 is presented. In this overview only phenolic antioxidant compounds that display significant anticancer activity have been described. In the first part of this review, the oxidative and nitrosative stress relation with cancer are described. In the second part, the plant-derived food extracts, containing identified phenolic antioxidants, the phenolic antioxidants isolated from plants and plant-derived food or commercially available and the synthetic ones, along with the type of cancer and cells where they exert anticancer activity, are described and summarized in tables. The principal mechanisms for their anti-proliferative effects were also described. Finally, a critical analysis of the studies and directions for future research are included in the conclusion.

EVALUATION OF ANTIMICROBIAL AND CYTOTOXIC ACTIVITIES OF PLANT EXTRACTS FROM SOUTHERN MINAS GERAIS CERRADO

The antimicrobial activity of plant hidroethanolic extracts on bacteria Gram positive, Gram negative, yeasts, Mycobacterium tuberculosis H37 and Mycobacterium bovis was evaluated by using the technique of Agar diffusion and microdilution in broth. Among the extracts evaluated by Agar diffusion, the extract of Bidens pilosa leaf presented the most expressive average of haloes of growth inhibition to the microorganisms, followed by the extract of B. pilosa flower, of Eugenia pyriformis' leaf and seed, of Plinia cauliflora leaf which statistically presented the same average of haloes inhibitory formation on bacteria Gram positive, Gram negative and yeasts. The extracts of Heliconia rostrata did not present activity. Mycobacterium tuberculosis H37 and Mycobacterium bovis(BCG) appeared resistant to all the extracts. The susceptibility profile of Candida albicans and Saccharomyces cerevisiae fungi were compared to one another and to the Gram positive Bacillus subtilis, Enterococcus faecalis and the Gram negative Salmonella typhimurium bacteria (p > 0.05). The evaluation of cytotoxicity was carried out on C6-36 larvae cells of the Aedes albopictus mosquito. The extracts of stem and flower of Heliconia rostrata, leaf and stem of Plinia cauliflora, seed of Anonna crassiflora and stem, flower and root of B. pilosa did not present toxicity in the analyzed concentrations. The highest rates of selectivity appeared in the extracts of stem of A. crassiflora and flower of B. pilosa to Staphylococcus aureus, presenting potential for future studies about a new drug development.

COMPARISON BETWEEN AUTOMATED SYSTEM AND PCR-BASED METHOD FOR IDENTIFICATION AND ANTIMICROBIAL SUSCEPTIBILITY PROFILE OF CLINICAL Enterococcus spp

Enterococci are increasingly responsible for nosocomial infections worldwide. This study was undertaken to compare the identification and susceptibility profile using an automated MicrosScan system, PCR-based assay and disk diffusion assay of Enterococcus spp. We evaluated 30 clinical isolates of Enterococcus spp. Isolates were identified by MicrosScan system and PCR-based assay. The detection of antibiotic resistance genes (vancomycin, gentamicin, tetracycline and erythromycin) was also determined by PCR. Antimicrobial susceptibilities to vancomycin (30 µg), gentamicin (120 µg), tetracycline (30 µg) and erythromycin (15 µg) were tested by the automated system and disk diffusion method, and were interpreted according to the criteria recommended in CLSI guidelines. Concerning Enterococcus identification the general agreement between data obtained by the PCR method and by the automatic system was 90.0% (27/30). For all isolates of E. faecium and E. faecalis we observed 100% agreement. Resistance frequencies were higher in E. faecium than E. faecalis. The resistance rates obtained were higher for erythromycin (86.7%), vancomycin (80.0%), tetracycline (43.35) and gentamicin (33.3%). The correlation between disk diffusion and automation revealed an agreement for the majority of the antibiotics with category agreement rates of > 80%. The PCR-based assay, the van(A) gene was detected in 100% of vancomycin resistant enterococci. This assay is simple to conduct and reliable in the identification of clinically relevant enterococci. The data obtained reinforced the need for an improvement of the automated system to identify some enterococci.

ANTIMICROBIAL DRUG RESISTANCE IN STRAINS OF Escherichia coli ISOLATED FROM FOOD SOURCES

A variety of foods and environmental sources harbor bacteria that are resistant to one or more antimicrobial drugs used in medicine and agriculture. Antibiotic resistance in Escherichia coli is of particular concern because it is the most common Gram-negative pathogen in humans. Hence this study was conducted to determine the antibiotic sensitivity pattern of E. coli isolated from different types of food items collected randomly from twelve localities of Hyderabad, India. A total of 150 samples comprising; vegetable salad, raw egg-surface, raw chicken, unpasteurized milk, and raw meat were processed microbiologically to isolate E. coli and to study their antibiotic susceptibility pattern by the Kirby-Bauer method. The highest percentages of drug resistance in isolates of E. coli were detected from raw chicken (23.3%) followed by vegetable salad (20%), raw meat (13.3%), raw egg-surface (10%) and unpasteurized milk (6.7%). The overall incidence of drug resistant E. coli was 14.7%. A total of six (4%) Extended Spectrum β-Lactamase (ESBL) producers were detected, two each from vegetable salads and raw chicken, and one each from raw egg-surface and raw meat. Multidrug resistant strains of E. coli are a matter of concern as resistance genes are easily transferable to other strains. Pathogen cycling through food is very common and might pose a potential health risk to the consumer. Therefore, in order to avoid this, good hygienic practices are necessary in the abattoirs to prevent contamination of cattle and poultry products with intestinal content as well as forbidding the use of untreated sewage in irrigating vegetables.

MOLECULAR IDENTIFICATION AND ANTIMICROBIAL RESISTANCE PATTERN OF SEVEN CLINICAL ISOLATES OF Nocardia spp. IN BRAZIL

Nocardia is a ubiquitous microorganism related to pyogranulomatous infection, which is difficult to treat in humans and animals. The occurrence of the disease is on the rise in many countries due to an increase in immunosuppressive diseases and treatments. This report of cases from Brazil presents the genotypic characterization and the antimicrobial susceptibility pattern using the disk-diffusion method and inhibitory minimal concentration with E-test® strips. In summary, this report focuses on infections in young adult men, of which three cases were cutaneous, two pulmonary, one neurological and one systemic. The pulmonary, neurological and systemic cases were attributed to immunosuppressive diseases or treatments. Sequencing analysis of the 16S rRNA segments (1491 bp) identified four isolates of Nocardia farcinica, two isolates of Nocardia nova and one isolate of Nocardia asiatica. N. farcinica was involved in two cutaneous, one systemic and other pulmonary cases; N. nova was involved in one neurological and one pulmonary case; and Nocardia asiatica in one cutaneous case. The disk-diffusion antimicrobial susceptibility test showed that the most effective antimicrobials were amikacin (100%), amoxicillin/clavulanate (100%), cephalexin (100%) and ceftiofur (100%), while isolates had presented most resistance to gentamicin (43%), sulfamethoxazole/trimethoprim (43%) and ampicillin (29%). However, on the inhibitory minimal concentration test (MIC test), only one of the four isolates of Nocardia farcinica was resistant to sulfamethoxazole/trimethoprim.

Effect of Efavirenz on High-Density Lipoprotein Antioxidant Properties in HIV-Infected Patients

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: * In previous work, we showed a long-term and concentration-dependent beneficial effect of the non-nucleoside reverse transcriptase inhibitor efavirenz (EFV) on high-density lipoproteins (HDL) in human immunodeficiency virus (HIV)-infected patients. * Furthermore, it has been suggested that instead of the current practice of only measuring HDL-chelesterol values, the evaluation of HDL function, namely its antioxidant properties, might be an improved tool for identifying subjects at increased risk for cardiovascular events. * Paraoxonase-1 (PON-1) is an enzyme associated with HDL that is responsible for HDL antioxidant function. WHAT THIS STUDY ADDS: * In the present work, we studied the effect of EFV on the activity of PON-1 and showed, for the first time, that EFV-based antiretroviral therapy is associated with a better antioxidant function, i.e. with a higher PON-1 activity. AIMS: A long-term and concentration-dependent beneficial effect of efavirenz (EFV) on cholesterol associated with high-density lipoprotein (HDL-c) in human immunodeficiency virus (HIV)-infected patients has been documented. Furthermore, it has been suggested that, instead of the current practice of only measuring HDL-c values, the evaluation of HDL quality might be an improved tool for identifying subjects at increased risk of cardiovascular events. Paraoxonase-1 (PON-1) is an enzyme associated with HDL that is involved in the onset of cardiovascular disease and responsible for HDL antioxidant function. The aim of the present study was to investigate the effect of EFV on the circulating activity of PON-1 in HIV-infected patients. METHODS: The patients included were adults with a documented HIV-1 infection, nontreated or treated with antiretroviral regimens including EFV 600 mg once daily as first therapeutic regimen for at least 3 months. The influence of treatment with EFV, HDL-c and CD4 cell count on PON-1 activity was analysed. RESULTS: HIV-infected White patients treated with EFV had higher PON-1 activity [77.35 U l(-1) (65.66, 89.04)] (P < 0.05) and higher PON-1 activity : HDL-c ratio [1.88 (1.49, 2.28)] (P < 0.01) than untreated patients. PON-1 activity was higher in Black patients (P < 0.001) and in patients with a CD4 cell count >500 cells ml(-1) (P= 0.0120). CONCLUSIONS: EFV-based antiretroviral regimens are associated with HDL particles with a better antioxidant function, i.e. with a higher PON-1 activity. The PON-1 activity of Black patients is higher than that found in Whites regardless of treatment. Ethnicity should be taken into consideration when studying drug effects on PON-1 activity.

SEROVARS AND ANTIMICROBIAL RESISTANCE OF Salmonella spp. ISOLATED FROM TURKEY AND BROILER CARCASSES IN SOUTHERN BRAZIL BETWEEN 2004 AND 2006

Salmonella spp. causes diseases in fowls, when species-specific serovars (Salmonella Pullorum and S.Gallinarum) are present in flocks, and public health problems, when non-typhoid serovars are isolated, as well as possible bacterial resistance induced by the preventive and therapeutic use of antimicrobials in animal production. This study describes the serovars and bacterial resistance of 280Salmonella spp. strains isolated from turkey and broiler carcasses in Southern Brazil between 2004 and 2006. SalmonellaEnteritidis was the most prevalent serovar (55.7%), followed by Heidelberg (5.0%), Agona (4.3%), Bredeney (3.9%), Hadar (3.2%), and Typhimurium (2.9%). Tennessee and S. Enterica subspecies enterica(O: 4.5) were isolated only in turkeys, and Hadar (18.6%) was the most prevalent serovar in this species. Antimicrobial susceptibility tests were performed in 178 isolates (43 from turkeys and 135 from broilers). All isolates were sensitive to amoxicillin + clavulanic acid, polymyxin B, ciprofloxacin, and norfloxacin, and were resistant to bacitracin and penicillin. Broiler carcass isolates showed resistance to nalidixic acid (48.9%), nitrofurantoin (34.3%), neomycin (9.6%), tetracycline (5.2%), and kanamycin (8.9%); and turkey carcass isolates were resistant to nalidixic acid (62.8%), tetracycline (34.9%), and neomycin (30.2%), with a significant difference in turkeys when compared to broiler carcass isolates. These results indicate the need for judicious use of antimicrobials in livestock production, given that the serovars identified are potential causes of food poisoning.

EPR and redox properties of periplasmic nitrate reductase from Desulfovibrio desulfuricans ATCC 27774

J Biol Inorg Chem (2006) 11: 609–616 DOI 10.1007/s00775-006-0110-0

Engineering of bacterial exopolysaccharides: from synthesis to properties

Dissertação para obtenção do Grau de Doutor em Engenharia Química e Bioquímica

Financial reporting about investment properties: Evidence from Portuguese listed companies

A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics

Exopolysaccharide production by Enterobacter A47: optimization of cultivation conditions and study of polymer functional properties

Dissertação para obtenção do Grau de Mestre em Biotecnologia

Mechanical and mineralogical properties of natural hydraulic lime-metakaolin mortars in different curing conditions

Construction and Building Materials 51 (2014) 287–294

New natural hydraulic lime mortars – Physical and microstructural properties in different curing conditions

Construction and Building Materials 54 (2014) 378–384

Novel insights into the action of antimicrobial agents against human pathogens

Dissertation presented to obtain the Ph.D degree in Biochemistry