Metagenomic study of bacterial microbiota in persistent endodontic infections using Next-generation sequencing.

AIM: To determine the bacterial microbiota in root canals associated with persistent apical periodontitis and their relationship with the clinical characteristics of patients using next-generation sequencing (NGS). METHODOLOGY: Bacterial samples from root canals associated with teeth having persistent apical periodontitis were taken from 24 patients undergoing root canal retreatment. Bacterial DNA was extracted, and V3-V4 variable regions of the 16S rRNA gene were amplified. The amplification was deep sequenced by Illumina technology to establish the metagenetic relationships among the bacterial species identified. The composition and diversity of microbial communities in the root canal and their relationships with clinical features were analysed. Parametric and nonparametric tests were used to analyse differences between patient characteristics and microbial data. RESULTS: A total of 86 different operational taxonomic units (OTUs) were identified and Good's nonparametric coverage estimator method indicated that 99.9 ± 0.00001% diversity was recovered per sample. The largest number of bacteria belonged to the phylum Proteobacteria. According to the medical history from the American Society of Anesthesiologists (ASA) Classification System, ASA II-III had higher richness estimates and distinct phylogenetic relationships compared to ASA I individuals (P < 0.05). Periapical index (PAI) score 5 was associated with increased microbiota diversity in comparison to PAI score 4, and this index was reduced in symptomatic patients. CONCLUSIONS: Based on the findings of this study, it is possible to suggest a close relationship between several clinical features and greater microbiota diversity with persistent endodontic infections. This work provides a better understanding on how microbial communities interact with their host and vice versa.

The application of the DAPSI(W)R(M) framework to the plastic pellets chain.

Single-use plastic, few global engagement and lack of policies contribute to the global challenge about plastic marine litter. This form of contamination can cause injury and death of marine wildlife. Microplastics (>5 mm) represent an important fraction of plastic litter. They include the plastic pellets that are used as raw material within plastic industry that can be unintentionally spilled into the environment during the industrial processes. In an initiative in order to facilitate the understanding and communication of plastic pellets as a social and environmental problem, we applied the Drivers-Activities-Pressures-State changes-Impacts (on Welfare)-Responses (as Measures) (DAPSI[W]R[M]) framework to plastic pellets chain. We also analyzed possible mitigating measures and their actions along the plastic pellets chain. This DAPSI(W)R(M) framework aim to show an overview of the plastic pellets chain and solutions for politicians and decision makers to help solve this socio-environmental problem that needs the engagement of all stakeholders involved.

The BioMask for treatment of corneal surface irregularities with excimer laser phototherapeutic keratectomy.

PURPOSE: To assess the characteristics of BioMask as a potential masking agent for use with the excimer laser. METHOD: We addressed ablation rate, smoothness, ease of use, dioptric shift, treatment of standardized irregular topography, and ability of BioMask to induce dioptric change in vivo. RESULTS: BioMask ablates at a rate of 0.28 microm per pulse. The BioMask conforms to the base curve of a contact lens in the excimer blank, eye bank eye, and rabbit eye with a r2 of 0.9982, 0.9844, 0.9858, respectively. We are readily able to create 20 diopters of flattening or steepening (r2 = 0.9944). Standardized irregular topography generation in the rabbit eye and then removal with BioMask was successful. The central corneal topography of the rabbit cornea showed predictable changes with various contact lens base curves with the BioMask (r2 = 0.875). CONCLUSIONS: BioMask has excellent potential as an ablatable mask material in the treatment of superficial corneal scars.

Atmospheric pressure plasma pretreatment of sugarcane bagasse: the influence of biomass particle size in the ozonation process.

Atmospheric pressure O2 plasma was used to produce ozone in order to treat sugarcane bagasse as a function of particle sizes. The fixed bagasse moisture content was 50%. The delignification efficiency had small improvement due to ozonation process as a function of particle size, varying from 75 up to 80%. Few amounts of hemicellulose were removed, but the ozonation has not been affected significantly with particle size variance as well (from 30 up to 35%). The cellulose presented some losses below 1.0 mm size (8-15%) which was an unexpected result. The conversion of cellulose content into free sugar has shown a significant increase as the particle size has diminished as well. The best condition of the bagasse particle size was for 0.08 mm. For this case, a great quantity of cellulose (78.8%) was converted into glucose. Optical absorption spectroscopy was applied to determine ozone concentrations in real time where the samples with typical bagasse particle sizes equal or below to 0.5 mm had shown a better absorption of ozone in comparison with greater particle size samples.

Atmospheric pressure plasma pretreatment of sugarcane bagasse: the influence of moisture in the ozonation process.

Sugarcane bagasse samples were pretreated with ozone via atmospheric O2 pressure plasma. A delignification efficiency of approximately 80 % was observed within 6 h of treatment. Some hemicelluloses were removed, and the cellulose was not affected by ozonolysis. The quantity of moisture in the bagasse had a large influence on delignification and saccharification after ozonation pretreatment of the bagasse, where 50 % moisture content was found to be best for delignification (65 % of the cellulose was converted into glucose). Optical absorption spectroscopy was applied to determine ozone concentrations in real time. The ozone consumption as a function of the delignification process revealed two main reaction phases, as the ozone molecules cleave the strong carbon-carbon bonds of aromatic rings more slowly than the weak carbon-carbon bonds of aliphatic chains.

Image analysis of modified cellulose fibers from sugarcane bagasse by zirconium oxychloride.

Surface modification of natural fibers has been made using different methods. In this paper, cellulose fibers from sugarcane bagasse were bleached and modified by zirconium oxychloride in situ. The chemically modified cellulose fibers were compared to those of bleached ones. Cellulose fibers were modified with ZrO(2).nH(2)O nanoparticles through the use of zirconium oxychloride in acidic medium in the presence of cellulose fibers using urea as the precipitating agent. The spatial distribution characterization of hydrous zirconium oxide on cellulose fibers was carried out by combining both processing and image analyses obtained by SEM and statistical methodologies. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analysis (TG) were also used to characterize the nanocomposite. Results indicated that ZrO(2).nH(2)O nanoparticles of about 30-80nm diameter deposited on cellulose fibers were heterogeneously dispersed.

Hernioplastia inguinal con malla sin tensión: experiencia con adhesivo N-butil-cianoacrilato / Tension-free hemioplasty: experience with adhesive N-butil-cianoacrilate

La hernioplastia de Lichtenstein es en la actualidad una de las técnicas más utilizadas en la reparación de hernia inguinal por su baja morbilidad y recurrencia y la reproducibilidad de sus resultados. Sin embargo, no está exenta de problemas postoperatorios como dolor e irritación local crónica atribuidos a las suturas para la fijación de la malla. El propósito del presente trabajo es mostrar los resultados a corto plazo utilizando en esta técnica un adhesivo biodegradable como medio de fijación, en reemplazo de suturas. Material y Método: Estudio prospectivo de 13 pacientes con hernia inguinal, 5 de ellas bilaterales, operados con la técnica de Lichtenstein, con un total de 18 hernioplastias. Para la fijación de la malla de polipropileno se empleó N-butil-cianocrilato. La edad media del grupo fue 45,8 años, con extremos de 25 y 62. El 84,6 por ciento fueron de sexo masculino. El 50 por ciento y 39 por ciento eran, respectivamente, hernias tipo II y Illa de Nyhus. Se excluyeron las hernias crurales y recidivadas. Se incluye una escala lineal análoga de 0 a 10 para evaluación del dolor postoperatorio. Seguimiento a corto plazo, media 8 meses, con extremos de 1 a 18 meses. Resultados: Estadía hospitalaria media 1,46 días. Escala lineal del dolor media 1er día 1,8 + 1,1 y 7º día 0. Evolución satisfactoria en todos los casos. Un paciente presenta hematoma leve en postoperatorio inmediato, de resolución espontánea. No hubo complicaciones mayores ni atribuibles al adhesivo. Sin recurrencias hasta cierre del estudio. Conclusiones: El N-butil-cianocrilato, para fijación de la malla en la técnica de Lichtenstein, presentó buenos resultados inmediatos, reforzando los beneficios y características de libre de tensión de la técnica, evitando la morbilidad del uso de suturas. Por otra parte, los costos de suturas y cantidad de adhesivo son comparables en su utilización.

Background: Lichtenstein hemioplasty is one of de most popular methods for inguinal hernia repair, due to its low rate of complications and recurrence. However it has some postoperative problems such as pain and local chronic irritations attributed to sutures for mesh fixation. Aim: To report the short term results of the use of a biodegradable adhesive to fix the mesh in Lichtenstein technique, instead of sutures. Material and Methods: Prospective study of 13 patients aged 25 to 62 years (11 men) with inguinal hernia, 5 bilateral, who were subjected to 18 hernia repair procedures, using Lichtenstein tension-free technique. The mesh fixed with the tissue adhesive, N-butyl-cyanocrylate. According to Nyhus hernia classification, 50 percent were type II, and 39 percent type Ilia. Femoral and recurrent hernias were excluded. A lineal analogue scale, from 0 to 10 was used to evaluate postoperative pain. The median follow-up was 8 months (range 1-18 months). Results: Mean hospital stay was 1.5 days. Mean pain score was 1.8 + 1.1 in the first postoperative day, and 0 at the 7th day. All had a good postoperative evolution. One patient had a hematoma that resolved spontaneously. No adhesive-related complications and no recurrences were seen. Conclusions: Good short term results were obtained using the he adhesive N-butyl-cyanocrylate, to fix the mesh in Lichtenstein hernioplasty.

Reabsorções dentais causadas pelo tratamento ortodôntico / Dental resorption caused by orthodontic treatment

Os autores realizaram um estudo radiográfico, utilizando uma amostra de 45 pacientes recém-egressos de tratamento ortodôntico, da freqüência com que ocorrem as reabsorções radiculares, em conseqüência dessa terapia e ainda as seguintes características: grau de reabsorção (que define a severidade da lesão), tipo de reabsorção (arredondado, oblíquo ou horizontal), contorno da raiz reabsorvida (liso ou irregular) e manutenção ou não do espaço peridentário e da cortical alveolar. Procuraram, ainda, sugerir um perfil mais provável para esta forma de reabsorção radicular