Change in Working Length at Different Stages of Instrumentation as a Function of Canal Curvature

The aim of this study was to determine the change in working length (∆WL) before and after coronal flaring and after complete rotary instrumentation as a function of canal curvature. One mesiobuccal or mesiolingual canal from each of 43 extracted molars had coronal standardization and access performed. Once the access was completed, canal preparation was accomplished using Gates Glidden drills for coronal flaring and EndoSequence files for rotary instrumentation. WLs were obtained at 3 time points: pre-instrumentation (unflared), mid-instrumentation (flared) and post-instrumentation (concluded). Measurements were made via direct visualization (DV) and the CanalPro apex locator (EM) in triplicate by a single operator with blinding within the time points. Root curvature was measured using Schneider’s technique. The change in working length was assessed using repeated-measures ANCOVA. The direct visualization measurements were statistically larger than the electronic measurements (paired t-test difference = 0.20 mm, SE = 0.037, P \u3c .0001), although a difference this large may not be clinically important. Overall, a greater change in working length was observed in straight canals than in curved canals, and this trend was more pronounced when measured electronically than via direct visualization, especially in the unflared-concluded time points compared with unflared-flared time points. A greater change in working length was also observed in longer canals than in shorter canals.https://scholarscompass.vcu.edu/gradposters/1032/thumbnail.jp

Halophilic Actinomycetes in 1 Saharan Soils of Algeria: Isolation, Taxonomy and Antagonistic Properties

The diversity of a population of 52 halophilic actinomycetes was evaluated by a polyphasic approach, which showed the presence of Actinopolyspora, Nocardiopsis, Saccharomonospora, Streptomonospora and Saccharopolyspora genera. One strain was considered to be a new member of the last genus and several other strains seem to be new species. Furthermore, 50% of strains were active against a broad range of indicators and contained genes encoding polyketide synthetases and nonribosomal peptide synthetases

A Cost Analysis of Carpal Tunnel Release Surgery Performed Wide Awake versus under Sedation.

BACKGROUND: Hand surgery under local anesthesia only has been used more frequently in recent years. The purpose of this study was to compare perioperative time and cost for carpal tunnel release performed under local anesthesia ( wide-awake local anesthesia no tourniquet, or WALANT) only to carpal tunnel release performed under intravenous sedation. METHODS: A retrospective comparison of intraoperative (operating room) surgical time and postoperative (postanesthesia care unit) time for consecutive carpal tunnel release procedures performed under both intravenous sedation and wide-awake local anesthesia was undertaken. All operations were performed by the same surgeon using the same mini-open surgical technique. A cost analysis was performed by means of standardized anesthesia billing based on base units, time, and conversion rates. RESULTS: There were no significant differences between the two groups in terms of total operative time, 28 minutes in the intravenous sedation group versus 26 minutes in the wide-awake local anesthesia group. Postanesthesia care unit times were significantly longer in the intravenous sedation group (84 minutes) compared to the wide-awake local anesthesia group (7 minutes). Depending on conversion rates used, a total of $139 to$432 was saved in each case performed with wide-awake local anesthesia by not using anesthesia services. In addition, a range of $1320 to$1613 was saved for the full episode of care, including anesthesia costs, operating room time, and postanesthesia care unit time for each patient undergoing wide-awake local anesthesia carpal tunnel release. CONCLUSION: Carpal tunnel release surgery performed with the wide-awake local anesthesia technique offers significant reduction in cost for use of anesthesia and postanesthesia care unit resources

Evaluation of sulfate resistance of calcined dolomite activated ground granulated blast furnace slag

Aggressive environments significantly influence the durability and serviceability of hardened cement and concrete. This paper presents an evaluation of the resistance of ground granulated blastfurnace slag (GGBS) activated with calcined dolomite, as a novel alkali activator, to 5% sodium sulfate attack and 5% magnesium sulfate attack. Two calcined dolomites, D800 and D1000, were prepared in the laboratory at 800 °C and 1000 °C respectively. The results demonstrated the good potential of using calcined dolomite activated slag in resisting sulfate attack. Immersion in Na2SO4(aq) led to an increase in strength in both the D800 (D800S) and the Portland cement CEM I 52.5N (PCS) activated slag, with a more pronounced effect in the former, while a decrease in the D1000 (D1000S) activated slag. On the other hand, calcined dolomite activated slag 25 had less strength loss than PCS after MgSO4 attack. The products of sulfate attack and the deterioration processes are also analyzed by a range of tests including pH, weight change, corroded depth, XRD, TGA and SEM/EDS. After Na2SO4 attack, the main product on D800S and D1000S was gypsum with a larger amount in the later. Gypsum, thaumasite and M-S-H were the main products of D800S and D1000S after MgSO4 attack. The better resistance of D800S to sulfate attack was attributed to the absence of portlandite in the hydrated paste. On the other hand, the presence of portlandite in D1000S led to the inhomogeneous sulfate ions inward progression hence the severe deterioration of sample was observed.This study was supported by the China Scholarship Council, the Key Project of the Natural Science Foundation of China (41230636) and the National Basic Research Program of China (2011CB710605). The second author also wants to thank the Cambridge Trust and the China Scholarship Council for the financial support.This is the author accepted manuscript. The final version is available from ASCE via http://dx.doi.org/10.1061/(ASCE)MT.1943-5533.000139

Surface defects in groove milling of Hastelloy-C276 under fluid coolant

This study aims to investigate surface integrity in groove milling of Hastelloy-C276 using coated carbide end mills under the application of water-based fluid coolant using different cutting parameters. Surface integrity was assessed by measuring surface roughness, using focus variation microscope, and investigating surface defects, using scanning electron microscope. Micro-chips re-deposition and long grooves dominated the machined surface at low cutting speed (24–50 m/min). While cracked and fractured re-deposited materials, grooves, large debris, and plastic flow dominated the machined surface at high cutting speed (70–120 m/min), consequently surface roughness increased with cutting speed. Nucleated cavities appeared at all cutting speeds but with different densities. Shallow depth of cut at low cutting speed gave negative effect on surface roughness due to the effect of the hardened layer. Overall, the best surface finish, with average roughness below 50 nm and minimum surface abuse, was obtained in the speed range of 24–50 m/min at feed rate of 1 µm/tooth and depth of cut deeper than 0.1 mm

Development and Validation of a LC-MS/MS Assay for Quantification of Parathyroid Hormone (PTH 1-34) in human Plasma

Background: Teriparatide [recombinant human PTH (1-34)] is an osteoanabolic agent for treatment of osteoporosis. The effect on bone decreases the risk of vertebral and non-vertebral fractures and increases bone mineral density (BMD) in post-menopausal women with osteoporosis. Measurement of PTH (1-34) is valuable in assessing treatment response and concordance with therapy.Aim: To develop and validate a method for quantification of PTH (1-34) using Liquid chromatography tandem mass spectrometry (LC-MS/MS) and to perform comparison with a commercial immunoassay.  Method: Sample extraction was developed using a Waters (Milford, MA, USA) Oasis® HLB µElution solid phase extraction. Quantification m/z transition 589>656 was used on Waters/Micromass® Quattro Ultima™ Pt mass spectrometer to measure PTH (1-34) in human plasma using rat PTH (1-34) as internal standard. Validation criteria were carried out against industry standards. PTH (1-34) results obtained from human subjects given Teriparatide (Fortsteo, Eli Lilly, IN, USA) (n=390) were compared against results obtained from an immunoassay (IDS; Boldon Tyne and Wear. UK).  Results and Discussion: LC-MS/MS produced a linear calibration curve from 10 to 2000 pg/mL (r2 >0.990). The LLoQ and LLoD for PTH (1-34) were 10 pg/mL and 2.1 pg/mL respectively. The inter- /intra-assay precision (CV%) of the method were 98.3% for four QCs (20, 100, 200, and 800 pg/mL). The mean recovery of PTH (1-34) was 107.2%. Method comparison between the LC-MS/MS and immunoassay using human EDTA plasma samples showed a high correlation (r2 = 0.950). A concentration-dependent, negative bias of 35.5% was observed across the range of 0 – 800 pg/mL. The immunoassay showed a 7% cross reactivity to human PTH (1-84) and 44% to rat PTH (1-34), no interference was observed in the LC-MS/MS method. Matrix effect and cross reactivity to human PTH (1-84) in the immunoassay were the likely contributing factors to the bias between the methods. The oxidised form of PTH (1-34) does not interfere with our LC-MS/MS method.  Conclusion: Our LC-MS/MS method demonstrated linearity over the calibration range, good precision and accuracy, excellent analyte recovery, and negligible matrix effects. The method was successfully used for measurements of PTH (1-34) in rat and human plasma