Behavior of deteriogenic fungi in aviation fuels (fossil and biofuel) during simulated storage.

Biofuels are expected to play a major role in reducing carbon emissions in the aviation sector globally. Farnesane ("2,6,10-trimethyldodecane") is a biofuel derived from the synthesized iso-paraffin route wich can be blended with jet fuel; however, the microbial behavior in farnesane/jet fuel blends remains unknown. The chemical and biological stability of blends should be investigated to ensure they meet the quality requirements for aviation fuels. This work aimed at evaluating the behavior of two fungi Hormoconis resinae (F089) and Exophiala phaeomuriformis (UFRGS Q4.2) in jet fuel, farnesane, and in 10% farnesane blend during simulated storage. Microcosms (150-mL flasks) were assembled with and without fungi containing Bushnell & Haas mineral medium for 28 days at a temperature of 20±2°C. The fungal growth (biomass), pH, surface tension, and changes in the fuel's hydrocarbon chains were evaluated. This study revealed thatthe treatment containing H. resinae showed a biomass of 19 mg, 12 mg, and 2 mg for jet fuel, blend, and farnesane respectively. The pH was reduced from 7.2 to 4.3 observed in jet fuel treatment The degradation results showed that compounds with carbon chains between C9 and C11, in jet fuel, and blend treatments were preferably degraded. The highest biomass (70.9 mg) produced by E. phaeomuriformis was in 10% farnesane blend, after 21 days. However, no significant decrease was observed on pH and surface tension measurements across the treatments as well as on the hydrocarbons when compared to the controls. This study revealed that farnesane neither inhibited nor promoted greater growth on both microorganisms.

Proanthocyanidins with Corrosion Inhibition Activity for AISI 1020 Carbon Steel under Neutral pH Conditions of Coconut (Cocos nucifera L.) Husk Fibers.

Cocos nucifera L. is a palm tree (Arecaceae) with a high economic value. The coconut husk fibers are nonedible, thick, and abrasion-resistant and correspond up to 85% of biomass discarded as solid waste residue. Therefore, the husk fibers are an underexploited byproduct with a high content of extractives of unreported nature. Two varieties of C. nucifera L. husk extracts were investigated to uncover bioactive metabolites and their possible application as a green corrosion inhibitor for carbon steel AISI 1020 under neutral pH conditions. The chemical analysis indicated 3% (w/w) of proanthocyanidins in the husk fibers with a high B-type procyanidin content. The husk fibers' crude extract showed promising results as an eco-friendly corrosion inhibitor for carbon steel AISI 1020 under neutral pH conditions. Although it formed a film on the metal surface in all tested concentrations (0.4, 0.8, 1.2, and 1.6 g L-1), the highest protective efficiency was shown at a concentration of 1.2 g L-1, determined by electrochemical techniques and mass loss. This was the first comprehensive report on coconut husk fibers' chemical composition, which was similar between the two varieties with potential for industrial application.

Detection of Sulphate-Reducing Bacteria and Others Cultivable Facultative Bacteria in Dental Tissues.

AIM: To detect for the presence of sulphate-reducing bacteria (SRB) and evaluate the possible association between SRB and cultivable facultative bacterial of oral sites with different periodontal conditions. METHODS: The study was carried out on 9 samples from different oral sites in 8 patients (two samples were collected from the same patient). Material was collected using modified Postgate E culture medium, indicated for the growth and isolation of SRB. In addition, a reducing solution for anaerobic bacteria was used as a transport solution for facultative bacteria and identified by polymerase chain reaction amplification (PCR) and sequencing of the 16S rRNA gene. RESULTS: SRB was found in 3 patient samples: the first in a root fragment, the second in a root fragment and a healthy tooth with vertical bone loss and a mobility degree of 3; and the third in a healthy tooth extracted for orthodontic treatment. In the final patient, the cultivable facultative species Lactobacillus casei was identified. Other facultative bacterial species were identified in patient 5 (Kurthia Gibsonii) and patient 7 (Pseudomonas aeruginosa). CONCLUSIONS: The detection of SRB in different dental tissues with distinct periodontal features demonstrated that new studies need to be developed in order to determine the true role of SRB in the oral microbiota. In addition, it was possible to verify the presence of Lactobacillus casei together with SRB in one sample.

Detection of sulphate-reducing bacteria in human saliva.

OBJECTIVE: The aim of the current study was to investigate the presence of sulphate-reducing bacteria (SRB) in human saliva and correlate with oral and systemic conditions. METHODS: Saliva samples were collected from 118 patients and inoculated in 2 ml of modified Postgate's E medium culture. After 28 days of incubation at 30°C the presence of SRB was identified by the production of sulphide. RESULTS: Of 118 saliva samples collected, 35 were positive for the presence of SRB. Three positive samples were randomly chosen to identify the species of SRB by PCR and sequenced. The three selected samples were identified as Desulfovibrio fairfieldensis, Desulfovibrio desulfuricans and Raoultella ornithinolytica. Gastritis (14.4%) was the most prevalent systemic disease, followed by diabetes (3.4%), while periodontitis (11%) and traumatic fibroma (4.2%) were the oral manifestations most frequently found. A bivariate analysis was performed to examine for the presence of SRB and the most prevalent systemic and oral manifestations. Only periodontitis showed a statistically significant association (p = 0.0003). CONCLUSIONS: The results showed SRB can be found in oral microbiota of healthy patients. Regarding the several conditions studied, there was a higher prevalence of SRB in patients with gastritis and patients with periodontal disease, with a possible correlation between the presence of SRB in the oral microbiota and periodontal disease.

Avaliação estereomicroscópica de limas endodônticas tipo K / Stereomicroscope evaluation of endodontics files K-type

As superfícies metálicas de dezesseis limas endodônticas tipo Kerr, novas, foram avaliadas através do uso de um microscópio esterioscópico. Todas as limas estudadas revelaram a existência de defeitos superficiais oriundos do processo de fabricação: partículas ao longo de todo o instrumento e/ou ranhuras de usinagem. A importância de caracterizar estes defeitos se reflete como um risco estrutural resultando em uma fratura inesperada do instrumento, obstrução do conduto radicular e o transporte destes fragmentos para a região perirradicular devido ao deslocamento das partículas presentes sobre a superfície metálica da lima.

The metallic surfaces of sixteen new Kerr-type endodontics files were evaluated through use of a stereomicroscope. All studied files showed surface defects from the manufacturing process: particles throughout the instrument and / or machining grooves. The importance of characterizing these defects is reflected as a structural risk resulting in an unexpected fracture of the instrument, obstruction of the root canal and transport of these fragments into the periradicular region due to displacement of the particles on the surface of the metal file.

Processos fisiológicos e patológicos das bactérias redutoras de sulfato do gênero desulfovibrio sp / Physiologic and pathological processes of the sulphate-reducing bacteria of the genus desulfovobrio sp

As bactérias redutoras de sulfato do gênero Desulfovibrio sp. podem ser encontradas normalmente formando parte da biota intestinal e oral de seres humanos saudáveis, participando, direta ou indiretamente, com seus produtos metabólicos, de diversas afecções como: periodontites, câncer colorretal, infecções e sepsemias. Propõe-se com esta revisão avaliar os aspectos normais e as possíveis alterações patológicas correlacionadas com as bactérias redutoras de sulfato no organismo humano. As conclusões levam a crer que o desequilíbrio na biota oral e intestinal pode levar a aumento no número de bactérias redutoras de sulfato e na produção de sulfeto, como produto metabólico final, podendo representar um fator adicional no desenvolvimento daquelas afecções. Além disso, por haver forte propensão para formar associações bacterianas, aumentando seu potencial patológico, pode ser difícil a identificação do seu verdadeiro papel nas morbidades em que estão envolvidas assim como o seu potencial virulento.

Sulfate-reducing bacteria of the genus Desulfovibrio spp. can be routinely detected as member of the normal intestinal and oral microbiota in health individuals. This bacterial group produces metabolic byproducts, which participate, direct or indirect, in several diseases, such as periodontitis, colorectal cancer, infections and sepsis. The purpose of the present study was to assess the association between sulfate-reducing bacteria and normal conditions and pathology alterations in human. In conclusion, it is possible that alteration of the oral and intestinal flora can result in increase of sulfate-reducing bacteria levels and products of sulfide as final metabolic. Therefore, these conditions can represent an important fact associated with those diseases. In addition, this bacterial group presents a great tendency in to associate with other microorganisms. Like that, it can increase the pathologic potential and can difficult the identification of the true involvement with several diseases as well as its virulent potential.