In vivo assessment of the impedance ratio method used in electronic foramen locators

<p>Abstract</p> <p>Background</p> <p>The results of an <it>in vivo </it>study on the "ratio method" used in electronic foramen locators (EFL) are presented. EFLs are becoming widely used in the determination of the working length (WL) during the root canal treatment. The WL is the distance from a coronal reference point to the point at which canal preparation and filling should terminate. The "ratio method" was assessed by many clinicians with the aim of determining its ability to locate the apical foramen (AF). Nevertheless, <it>in vivo </it>studies to assess the method itself and to explain why the "ratio method" is able to locate the apical foramen and is unable to determine intermediate distances were not published so far.</p> <p>Methods</p> <p>A developed apparatus applies an electrical current signal with constant amplitude of 10 μA_RMSthrough the endodontic file within the root canal. The applied current signal is composed by summing six sine waves, from 250 Hz to 8 kHz. Data were acquired with the endodontic file tip at 7 different positions within root canals. In the frequency domain the quotients between the amplitude of a reference frequency and the amplitudes of the other frequencies components were calculated. Twenty one root canals were analyzed in vivo, during the endodontic treatment of twelve teeth of different patients, with age between 20 to 55 years.</p> <p>Results</p> <p>For the range of frequencies used in the commercial EFLs and for distances ranging from -3 mm to -1 mm of the AF, the impedance of the root canal is mainly resistive. However, when the file tip gets closer to AF, the root canal electrical impedance starts to change from a mainly resistive to a complex impedance. This change in the measured root canal impedance starts when the file tip is near -1.0 mm from the AF, getting stronger as the file tip gets closer to the AF. This change in the impedance behavior affects the ratio (quotient) of the impedance measured at different frequencies. Through graphic analysis it is demonstrated why EFLs based on the ratio method are unable to accurately measure any distances between - 3.0 and -0.5 mm from the apical foramen. The only reliable measurement is the 0 mm distance, which is when the file tip is at the AF.</p> <p>Conclusions</p> <p>The electrical impedance values of 21 root canals were <it>in vivo </it>studied. The results confirm the ability of EFLs that are based on the ratio method to accurately locate the AF position and explain why they are unable to determine the file tip position along the root canal.</p

Enantioselective Determination of Fluoxetine and Norfluoxetine in Wastewater

Microbial degradation of chiral compounds during wastewater treatment processes can be enantioselective and needs chiral analytical methodology to discriminate the biodegradation of both enantiomers. An enantioselective HPLC-FD method was developed and validated to monitor the degradation of fluoxetine (FLX) enantiomers by wastewater and the possible formation of its metabolite norfluoxetine (NFLX). The Solid Phase Extraction (SPE) of 50 mL of wastewater samples on 500 mg Oasis MCX cartridges was followed by the HPLC analysis using a Chirobiotic V chiral stationary phase under reversed mode. The developed method wasvalidated within the wastewater effluent used in microcosms laboratory assays. The chiral SPE-HPLC-FD method demonstrated to be selective, linear, sensitive, accurate and precise to quantify the enantiomers of FLX and of its metabolites NFLX in wastewaters. The limits of detection (0.8-2.0 ng mL -1 ) and quantification (2.0 – 4.0 ng mL -1 ) were adequate to monitoring the degradation assays at environmental level. The method proved to be robust to follow the biodegradation assays using real wastewater samplesspiked with FLX, during 46 days. To the best of our knowledge, this is the first reportof simultaneous separation of FLX and NFLX enantiomers using a Chirobiotic V and the application of the validated method to the enantioselective degradation by wastewate

Enantioselective Degradation of Enantiomers of Fluoxetine Followed by HPLC- FD

Environmental fate assessment of chiral pharmaceuticals is an important issue and little information is known about enantioselectivity in the environment. This kind of information is important for regulamentation of pharmaceutical industry and chiral switching processes. Fluoxetine (FLX), an anti-depressant worldwide used, is a chiral pharmaceutical prescribed in racemic form, and its main metabolite norfluoxetine (NFLX) is also chiral. In this study, enantioselective degradation of rac-FLX and degradation of its enantiomers separately, in a minimal salts medium inoculated by a bacterium consortium was examined both at light and dark conditions. Theassays were performed in a shaker at aerobic and ambient temperature conditions. The analytical method used was an enantioselective HPLC-FD method using a vancomycin-based chiral stationary phase in reversed mode to monitor enantiomers of FLX and NFLX. No degradation of enantiomers of FLX in the abiotic controls was observed. In theall assays (R)-FLX was degraded faster and totally until day 24th while (S)-FLX remained up to 20% of its initial concentration until the end of the experiment (38 days). NFLX wasdetected in all biotic experiments

Concomitant infection of Neospora caninum and Bovine Herpesvirus type 5 in spontaneous bovine abortions1

Bovine Herpesvirus type 5 (BoHV-5) has not been conclusively demonstrated to cause bovine abortion. Brain lesions produced by Neospora caninum and Bovine Herpesvirus type 1 (BoHV-1) exhibit common features. Therefore, careful microscopic evaluation and additional diagnostic procedures are required to achieve an accurate final etiological diagnosis. The aim of the present work was to investigate the occurrence of infections due to BoHV-1, BoHV-5 and N. caninum in 68 cases of spontaneous bovine abortions which showed microscopic lesions in the fetal central nervous system. This study allowed the identification of 4 (5.9%) fetuses with dual infection by BoHV-5 and N. caninum and 33 (48.5%) cases in which N. caninum was the sole pathogen identified. All cases were negative to BoHV-1. The results of this study provide evidence that dual infection by BoHV-5 and N. caninum occur during pregnancy in cattle; however, the role of BoHV-5 as a primary cause of bovine abortion needs further research. Molecular diagnosis of BoHV-5 and N. caninum confirmed the importance of applying complementary assays to improve the sensitivity of diagnosing bovine abortion.Fil: Marin, Maia Solange. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires. Estación Experimental Agropecuaria Balcarce; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina;Fil: Morrell, Eleonora Lidia. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires. Estación Experimental Agropecuaria Balcarce; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina;Fil: Perez, Sandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Tandil. Centro de Investigacion Veterinaria de Tandil; Argentina;Fil: Leunda, Maria R.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires. Estación Experimental Agropecuaria Balcarce; Argentina;Fil: Moore, Dadin Prando. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires. Estación Experimental Agropecuaria Balcarce; Argentina;Fil: Jones, Leandro Roberto. Fund.Playa Union. Estacion de Fotobiologia Playa Union; Argentina;Fil: Campero, Carlos Manuel. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires. Estación Experimental Agropecuaria Balcarce; Argentina;Fil: Odeon, Anselmo Carlos. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires. Estación Experimental Agropecuaria Balcarce; Argentina

Gastrointestinal adverse events during methylphenidate treatment of children and adolescents with attention deficit hyperactivity disorder:A systematic review with meta-analysis and Trial Sequential Analysis of randomised clinical trials

OBJECTIVES:To study in more depth the relationship between type, dose, or duration of methylphenidate offered to children and adolescents with attention deficit hyperactivity disorder and their risks of gastrointestinal adverse events based on our Cochrane systematic review. METHODS AND FINDINGS:We use data from our review including 185 randomised clinical trials. Randomised parallel-group trials and cross-over trials reporting gastrointestinal adverse events associated with methylphenidate were included. Data were extracted and quality assessed according to Cochrane guidelines. Data were summarised as risk ratios (RR) with 95% confidence intervals (CI) using the inverse variance method. Bias risks were assessed according to domains. Trial Sequential Analysis (TSA) was used to control random errors. Eighteen parallel group trials and 43 cross-over trials reported gastrointestinal adverse events. All trials were at high risk of bias. In parallel group trials, methylphenidate decreased appetite (RR 3.66, 95% CI 2.56 to 5.23) and weight (RR 3.89, 95% CI 1.43 to 10.59). In cross-over trials, methylphenidate increased abdominal pain (RR 1.61, 95% CI 1.27 to 2.04). We found no significant differences in the risk according to type, dose, or duration of administration. The required information size was achieved in three out of four outcomes. CONCLUSION:Methylphenidate increases the risks of decreased appetite, weight loss, and abdominal pain in children and adolescents with attention deficit hyperactivity disorder. No differences in the risks of gastrointestinal adverse events according to type, dose, or duration of administration were found

Design, Environmental and Sustainability Constraints of new African Observatories: The example of the Mozambique Radio Astronomy Observatory

The Mozambique Radio Astronomy Observatory (MRAO) will be a first milestone towards development of radioastronomy in Mozambique. Development of MRAO will constitute a preparation step towards participation in the upcoming Africa VLBI Network and the Square Kilometer Array project. The MRAO first antenna is planned to serve as a capacitation and training facility and will be installed after the conversion of a 7-meter telecom dish in South Africa. Therefore, this first radiotelescope design has to comply with local spectral and environmental constraints. Furthermore, power availability and long term sustainability with potential inclusion of solar power and control of Radio Frequency Interference are analyzed. Here we outline some of the design, environmental and power sustainability constraints.Comment: 5 pages, 3 Figures; Proceedings of the URSI BEJ Session 'Large Scale Science Projects: Europa-Africa Connects', IEEE Africon 2013 Conference Mauritius (9-12 Sep) 2013, Accepted for Publication at IEEE Xplorer, Nov 201