Stability of Doxycycline Absorbed on Root Canal Dentin After Obturation with Gutta-Percha/AH26 and Resilon/RealSeal at Different Time Intervals

Objective: Eradication of microorganisms present in the root canal system is paramount for the successful outcome of root canal therapy. The purpose of this study was to compare the of doxycycline absorbed from MTAD into root canal dentin after obturation with gutta-percha/AH26 and Resilon/RealSeal at different time intervals.Materials and Methods: Fifty-one extracted human teeth were instrumented. Thirty samples were obturated with either gutta-percha/AH26 or Resilon/self-etch RealSeal after final irrigation with MTAD. Fifteen samples were kept unobturated (positive control); six samples were obturated with either gutta-percha/AH26 or Resilon/self-etch RealSeal without MTAD irrigation (negative control).After aging for 1, 3 or 6 weeks, dentin debri were collected, the Doxycycline compound was extracted and its amount was quantified using high performance liquid chromatography. The statistical significance of the change in Doxycycline concentrations was tested with two-way ANOVA.Results: The mean concentration of Doxycycline in dentin for one, three and six-week guttapercha/AH26 samples was 1.8±0.36, 1.22±0.22 and 0.67±0.11 respectively, whereas these concentrations in Resilon/RealSeal samples were 1.60±0.26, 0.80±0.14 and 0.59±0.01 respectively. Regarding the positive control group, these concentrations were 2.09±0.11, 1.54±0.12 and 0.72±0.07 respectively for 1, 3 and 6-week intervals. No Doxycycline was detected in negative control groups. The Doxycycline concentrations showed a significant difference forobturating materials (p=0.008). These concentrations were higher in the gutta-percha/AH26 samples than Resilon/RealSeal samples in each time interval.Conclusion: The remaining amount of Doxycycline bonded to dentin was higher when root canals were obturated with gutta-percha/AH26 compared to Resilon/RealSeal. The stability of Doxycycline showed a time dependent decrease

Effects of acidifiers on soil greenhouse gas emissions in calcareous soils in a semi-arid area

Abstract In most agricultural fields, when soil pH is high, elemental sulfur or sulfuric acid are used to reduce soil pH and increase the availability of macro and micronutrients for optimum crop yield. However, how these inputs impact soil greenhouse gas emissions is unknown. This study aimed to measure the amount of greenhouse gas emissions and pH after the application of various doses of elemental sulfur (ES) and sulfuric acid (SA). Using static chambers, this study quantifies soil greenhouse gas emissions (CO2, N2O, and CH4) for 12 months after the application of ES (200, 400, 600, 800, and 1000 kg ha−1) and SA (20, 40, 60, 80 and 100 kg ha−1) to a calcareous soil (pH 8.1) in Zanjan, Iran. Also, in order to simulate rainfed and dryland farming which are common practices in this area, this study was conducted with and without sprinkler irrigation. Application of ES slowly decreased soil pH (more than half a unit) over the year whereas application of SA temporarily reduced the pH (less than a half unit) for a few weeks. CO2 and N2O emissions and CH4 uptake were maximum during summer and lowest in winter. Cumulative CO2 fluxes ranged from 1859.2 kg−1 CO2-C ha−1 year−1 in the control treatment to 2269.6 kg CO2-C ha−1 year−1 in the 1000 kg ha−1 ES treatment. Cumulative fluxes for N2O-N were 2.5 and 3.7 kg N2O-N ha−1 year−1 and cumulative CH4 uptakes were 0.2 and 2.3 kg CH4-C ha−1 year−1 in the same treatments. Irrigation significantly increased CO2 and N2O emissions and, depending on the amount of ES applied, decreased or increased CH4 uptake. SA application had a negligible effect on GHGs emissions in this experiment and only the highest amount of SA altered GHGs emissions

Hydroxy decenoic acid down regulates <it>gtfB</it> and <it>gtfC</it> expression and prevents <it>Streptococcus mutans</it> adherence to the cell surfaces

<p>Abstract</p> <p>Background</p> <p>10<b>-</b>Hydroxy-2-decenoic acid, an unsaturated fatty acid is the most active and unique component to the royal jelly that has antimicrobial properties. <it>Streptococcus mutans</it> is associated with pathogenesis of oral cavity, gingivoperiodontal diseases and bacteremia following dental manipulations. In the oral cavity, <it>S. mutans</it> colonize the soft tissues including tongue, palate, and buccal mucosa. When considering the role of supragingival dental plaque in caries, the proportion of acid producing bacteria (particularly <it>S. mutans</it>), has direct relevance to the pathogenicity of the plaque. The genes that encode glucosyltransferases (<it>gtf</it>s) especially <it>gtfB</it> and <it>gtfC</it> are important in <it>S. mutans</it> colonization and pathogenesis. This study investigated the hydroxy-decenoic acid (HDA) effects on <it>gtfB</it> and <it>gtfC</it> expression and <it>S. mutans</it> adherence to cells surfaces.</p> <p>Methods</p> <p><it>Streptococcus mutans</it> was treated by different concentrations of HPLC purified HDA supplied by Iran Beekeeping and Veterinary Association. Real time RT-PCR and western blot assays were conducted to evaluate <it>gtfB</it> and <it>gtfC</it> genes transcription and translation before and after HDA treatment. The bacterial attachment to the cell surfaces was evaluated microscopically.</p> <p>Results</p> <p>500 μg ml^-1 of HDA inhibited <it>gtfB</it> and <it>gtfC</it> mRNA transcription and its expression. The same concentration of HDA decreased 60% the adherence of <it>S. mutans</it> to the surface of P19 cells.</p> <p>Conclusion</p> <p>Hydroxy-decenoic acid prevents <it>gtfB</it> and <it>gtfC</it> expression efficiently in the bactericide sub-concentrations and it could effectively reduce <it>S. mutans</it> adherence to the cell surfaces. In the future, therapeutic approaches to affecting <it>S. mutans</it> could be selective and it’s not necessary to put down the oral flora completely.</p

Intraoperative Sonographic Guided Pull-through Anorectoplasty: A Novel Procedure for Imperforate Anus and Rectourethral Fistula: A Clinical Trial Study

Background and objectives: Optimal surgical management of the neonate with imperforate anus (IA) depends on determining accurate location of muscle complex, pouch of rectum and urethral fistula. The aim of this study was to investigate a novel minimally invasive technique of anorectoplasty assisted by intraoperative sonography pull-through for repair of anorectal malformation and rectourinary fistula.Patients and methods: Eight male patients with imperforate anus aged under 48 h had undergone colostomy. Any associated anomalies were evaluated in cases. After 5-8 weeks, neonates were prepared for anoplasty. After catheterization, sonography of perinea was carried out. Patients were placed in lithotomy position. The accurate position of each required point was determined by this procedure.Results: In all cases, the pouch of rectum to skin distance was in range 1.5-1.8 mm and entrance distance of wire to fistula was maximally 6 mm, just in one patient this value was 7 mm. Anomalies associated with some patients were Down Syndrome, cardiac anomalies, kidney disease .6 out of 8 patients removed urinary catheter after two days and discharged home. Colostomy of all patients was closed after sonography of prinea. After one week and one month follow- up, all patients had an acceptable fecal frequency about 3- 5 times a day.Conclusion:Intra-operative sonography is an applicable procedure to determine correct location of muscle complex, pouch of rectum and uretral fistula to treat IA patients non- invasively. Another interesting point of this study is the ability of non invasive surgery and novel procedure with perfect result

Wastewater and surface monitoring to detect COVID-19 in elementary school settings: The Safer at School Early Alert project.

UNLABELLED: Schools are high-risk settings for SARS-CoV-2 transmission, but necessary for children’s educational and social-emotional wellbeing. While wastewater monitoring has been implemented to mitigate outbreak risk in universities and residential settings, its effectiveness in community K-12 sites is unknown. We implemented a wastewater and surface monitoring system to detect SARS-CoV-2 in nine elementary schools in San Diego County. Ninety-three percent of identified cases were associated with either a positive wastewater or surface sample; 67% were associated with a positive wastewater sample, and 40% were associated with a positive surface sample. The techniques we utilized allowed for near-complete genomic sequencing of wastewater and surface samples. Passive environmental surveillance can complement approaches that require individual consent, particularly in communities with limited access and/or high rates of testing hesitancy. ONE SENTENCE SUMMARY: Passive wastewater and surface environmental surveillance can identify up to 93% of on-campus COVID-19 cases in public elementary schools; positive samples can be sequenced to monitor for variants of concerns with neighborhood level resolution