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

Exclusive measurement of coherent eta photoproduction from the deuteron

Coherent photoproduction of eta mesons from the deuteron has been measured from threshold up to incident photon energies of 750 MeV using the photon spectrometer TAPS at the tagged photon facility at the Mainz microtron MAMI. For the first time, differential coherent cross sections have been deduced from the coincident detection of the eta meson and the recoil deuteron. A missing energy analysis was used for the suppression of background events so that a very clean identification of coherent eta-photoproduction was achieved. The resulting cross sections agree with previous experimental results except for angles around 90 deg in the photon-deuteron cm-system where they are smaller. They are compared to various model calculations.Comment: 4 pages, 4 figure

Effects of Increasing Levels of Copper from Either CuSO4 or Combinations of CuSO4 and a Cu-Amino Acid Complex on Growth Performance, Carcass Characteristics, and Economics of Finishing Pigs

A total of 1,089 pigs (PIC 280 ×1050; initially 82.2 lb) were used in a 105-d experiment to determine the effects of increasing added Cu from either CuSO4 alone or a 50/50 blend of CuSO4 and Cu-AA (Availa®-Cu, Zinpro Corporation, Eden Prairie, MN) on growth performance, carcass characteristics, and economics of finishing pigs. All 6 dietary treatments contained 17 ppm Cu from CuSO4 from the trace mineral premix. Additional treatment diets contained added CuSO4 to provide 70 and 130 ppm total Cu or a 50/50 blend of added Cu from CuSO4 and Cu-AA to provide 70, 100, and 130 ppm total Cu. There were 25 or 26 pigs per pen and 7 replicate pens per treatment.Overall, added Cu above 17 ppm did not influence ADG; however, pigs fed 70 and 130 ppm added Cu from the 50/50 blend of CuSO4 and Cu-AA had decreased (P = 0.045) ADFI and improved feed efficiency (P = 0.048) compared with those fed 70 and 130 ppm of added Cu from CuSO4 only. Similar to the F/G response, pigs fed diets that contained CuSO4 alone had poorer (P = 0.030) carcass F/G than those fed added Cu from the 50/50 blend of CuSO4 and Cu-AA. Neither Cu source nor level influenced economics.In conclusion, these data suggest pigs fed diets that contained added Cu from CuSO4 alone consume more feed but have poorer feed efficiency which translates into poorer carcass F/G compared to those fed a 50/50 blend of CuSO4 and Cu-AA. Copper level did not impact growth performance. Based on our study, it appears that the 50/50 blend of CuSO4/Cu-AA optimized feed efficiency and carcass feed efficiency of pigs marketed on a constant time basis

Religious conversion among high security hospital patients: a qualitative analysis of patients’ accounts and experiences on changing faith

Research has shown the importance of religion in recovery from mental illness. Previous studies have investigated why individuals change faith during custody in prison, but there has been no research to date on religious conversion in forensic-psychiatric hospitals. The aim of this study was to understand the experience of religious conversion among patients detained in a UK secure hospital. Thirteen patients who had converted their religion were interviewed and the resultant data were analysed using thematic analysis. Three superordinate themes (‘reasons for changing faith’, ‘benefits of having a new faith’ and ‘difficulties with practising a faith’), incorporating eight subordinate themes, emerged. Understanding patients’ reasons for religious conversion is important for the treatment and support not merely of these individuals, but more broadly with patients in forensic psychiatric care

Effect of added zinc in diets with ractopamine hydrochloride on growth performance, carcass characteristics, and ileal mucosal inflammation mRNA expression of finishing pigs

Citation: Paulk, C. B., Burnett, D. D., Tokach, M. D., Nelssen, J. L., Dritz, S. S., Derouchey, J. M., . . . Gonzalez, J. M. (2015). Effect of added zinc in diets with ractopamine hydrochloride on growth performance, carcass characteristics, and ileal mucosal inflammation mRNA expression of finishing pigs. Journal of Animal Science, 93(1), 185-196. doi:10.2527/jas2014-8286Two experiments were conducted to determine the effects of increasing the dietary Zn content on growth performance, carcass characteristics, plasma Zn, and ileal mucosal inflammation mRNA expression of finishing pigs fed diets containing ractopamine HCl (RAC; Elanco Animal Health, Greenfield, IN). In Exp. 1, 312 pigs (327 × 1050; PIC, Hendersonville, TN; 94 kg BW) were used in a 27-d study. There were 2 pigs per pen and 26 pens per treatment. Treatments included a corn–soybean meal diet (control; 0.66% standardized ileal digestible [SID] Lys); a diet (0.92% SID Lys) with 10 mg/kg RAC; and the RAC diet plus 50, 100, or 150 mg Zn/kg from ZnO or 50 mg Zn/kg from a Zn AA complex (ZnAA; Availa-Zn; Zinpro, Eden Prairie, MN). All diets also contained 83 mg Zn/kg from ZnSO4 in the trace mineral premix. Pigs fed the RAC diet without added Zn had increased (P &lt; 0.05) ADG, G:F, HCW, carcass yield, and loin weight compared with pigs fed the control diet. Increasing Zn from ZnO in diets containing RAC tended to increase (linear, P = 0.067) G:F and loin weight (quadratic, P = 0.064). Pigs fed diets with 50 mg Zn/kg from ZnAA tended to have increased (P = 0.057) ADG compared with pigs fed the RAC diet. In Exp. 2, 320 pigs (327 × 1050; PIC; 98 kg BW) were used in a 35-d study. There were 2 pigs per pen and 20 pens per treatment. Treatments included a control diet (0.66% SID Lys); a diet (0.92% SID Lys) with 10 mg/ kg RAC; or the RAC diet plus 75, 150, and 225 mg Zn/ kg from ZnO or ZnAA. All diets also contained 55 mg Zn/kg from ZnSO4 from the trace mineral premix. Pigs fed the RAC diet had increased (P &lt; 0.05) ADG, G:F, HCW, loin depth, percentage lean, and liver weight compared with pigs fed the control diet. No Zn level or source effects or level × source interactions were observed for growth performance. A Zn level × source interaction (quadratic, P = 0.007) was observed in liver Zn concentrations. This resulted from liver Zn concentrations plateauing at 150 mg Zn/kg when ZnO was supplemented, while there was a linear increase when using ZnAA. Increasing Zn in diets containing RAC increased (linear, P &lt; 0.05) plasma Zn on d 18 and 32. The expression of IL-1? was increased (P = 0.014) in mucosa of pigs fed the RAC diet compared with those fed the control diet. Expression of IL-1? decreased (linear, P = 0.026) in the mucosa of pigs fed increasing added Zn. In conclusion, adding Zn to diets containing RAC resulted in a trend for improved growth performance of pigs in 1 of 2 experiments. Also, additional Zn increased plasma Zn and reduced IL-1?. © 2015 American Society of Animal Science. All rights reserved

Photoproduction of pi0-mesons from nuclei

Photoproduction of neutral pions from nuclei (carbon, calcium, niobium, lead) has been studied for incident photon energies from 200 MeV to 800 MeV with the TAPS detector using the Glasgow photon tagging spectrometer at the Mainz MAMI accelerator. Data were obtained for the inclusive photoproduction of neutral pions and the partial channels of quasifree single pi0, double pi0, and pi0pi+/- photoproduction. They have been analyzed in terms of the in-medium behavior of nucleon resonances and the pion - nucleus interaction. They are compared to earlier measurements from the deuteron and to the predictions of a Boltzmann-Uehling-Uhlenbeck (BUU) transport model for photon induced pion production from nuclei.Comment: 15 pages, 22 figures, accepted for publication in EPJ

Coherent \pi^\circ photoproduction from ^4He

Differential cross sections and beam asymmetries for coherent \pi^\circ photoproduction from ^4He in the \Delta energy-range have been measured with high statistical and systematic precisions using both decay photons for identifying the process.The experiment was performed at the MAinz MIcrotron using the TAPS photon spectrometer and the Glasgow/Mainz tagged photon facility. The differential cross sections are in excellent agreement with predictions based on the DWIA if an appropriate parametrization of the \Delta-nuclear interaction is applied. The beam asymmetries are interpreted in terms of degrees of linear polarization of collimated coherent bremsstrahlung. The expected increase of the degree of linear polarization with decreasing collimation angle is confirmed. Agreement with calculations is obtained on a few-percent level of precision in the maxima of the coherent peaks.Comment: 22 pages, 6 figure

Threshold enhancement in eta photoproduction from 2H and 4He

The photoproduction of eta-mesons from 2H and 4He has been studied for energies close to the production thresholds. The experiments were carried out with the tagged photon beam of the Mainz MAMI accelerator. The eta-mesons were detected via their two photon decays with the electromagnetic calorimeter TAPS. Total cross sections, angular and momentum distributions of the eta-mesons have been determined for both reactions. The total cross sections in the threshold region show a large enhancement over the predictions of a participant - spectator model, indicating significant final state interaction effects. The results are compared to recent model calculations taking into account nucleon-nucleon and nucleon-eta final state interaction effects on different levels of sophistication.Comment: 8 pages, 6 figure