•A separation-based assay enables detection of product in the presence of substrate.•Capillary electrophoresis is suitable for analysis of enzyme in limited quantities.•Basic principles of capillary ...electrophoresis and enzyme analysis are covered.•KM determinations from 2012 to 2017 are summarized.
Capillary electrophoresis provides a rapid, cost-effective platform for enzyme and substrate characterization. The high resolution achievable by capillary electrophoresis enables the analysis of substrates and products that are indistinguishable by spectroscopic techniques alone, while the small volume requirement enables analysis of enzymes or substrates in limited supply. Furthermore, the compatibility of capillary electrophoresis with various detectors makes it suitable for KM determinations ranging from nanomolar to millimolar concentrations. Capillary electrophoresis fundamentals are discussed with an emphasis on the separation mechanisms relevant to evaluate sets of substrate and product that are charged, neutral, and even chiral. The basic principles of Michaelis-Menten determinations are reviewed and the process of translating capillary electrophoresis electropherograms into a Michaelis-Menten curve is outlined. The conditions that must be optimized in order to couple off-line and on-line enzyme reactions with capillary electrophoresis separations, such as incubation time, buffer pH and ionic strength, and temperature, are examined to provide insight into how the techniques can be best utilized. The application of capillary electrophoresis to quantify enzyme inhibition, in the form of KI or IC50 is detailed. The concept and implementation of the immobilized enzyme reactor is described as a means to increase enzyme stability and reusability, as well as a powerful tool for screening enzyme substrates and inhibitors. Emerging techniques focused on applying capillary electrophoresis as a rapid assay to obtain structural identification or sequence information about a substrate and in-line digestions of peptides and proteins coupled to mass spectrometry analyses are highlighted.
In this paper, novel integer programming formulations are developed for solving the optimal scheduling of patients waiting for radiotherapy treatment. In this specific clinical domain, the suitable ...management and control of a patients’ waiting list strongly affect both the quality of the therapeutical outcome, in terms of effectiveness, and the cost-saving use of the overall therapeutical resources, in terms of efficiency. The proposed models allow the best scheduling strategy to be devised by taking into account the quality of the health care service offered to the patient as well as the status and the preferences of the patient. The computational experiments, carried out on realistic scenarios and considering real data, are very promising and show the efficiency and robustness of the proposed models to address the problem under consideration.
Aim To analyse the shaping ability of two new NiTi rotary systems in molar curved canals.
Methodology Thirty molar root canals with curvatures from 24° to 69° were divided into two groups that were ...balanced in terms of curvature. The canals in one group were shaped using the Mtwo (Sweden & Martina, Padova, Italy) and the canals in the other group using the Endoflare–Hero Shaper (Micro‐Mega, Besançon, France) in a modified sequence. Pre‐ and post‐instrumentation X‐rays were taken using a radiographic platform, with a contrast medium being used to enhance canal opacity. The dentine removed at five positions along the canals, the symmetry of canal shaping and the presence of aberrations were analysed through computer‐aided measurements. The instrument failures, the working time and the changes in working length were also recorded. The Mann–Whitney U‐test was used for statistical analyses.
Results Both systems produced uniform dentine removal and symmetrical canal shapes; there was no significant difference between the systems (P > 0.05). In the apical region, preparations were centred in the canal. A mean loss of working length of 0.55 mm for Mtwo and 0.58 mm for Endoflare–Hero Shaper was detected, with no significant differences between the instruments (P > 0.05). No aberrations were seen and no instruments separated. The mean working time was 124.4 s for the Mtwo system and 141.3 s for the Endoflare–Hero Shaper but this difference was not statistically significant (P > 0.05).
Conclusion The systems tested in this study were effective in shaping curved canals in extracted teeth.
Pion–Muon separation with a RICH prototype for the NA62 experiment Angelucci, B.; Anzivino, G.; Avanzini, C. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2010, Volume:
621, Issue:
1
Journal Article
Peer reviewed
The NA62 experiment at CERN, aimed to measure
K
+
→
π
+
ν
ν
¯
branching fraction (O(10
−10)), relies on a Neon based RICH detector for
π
/
μ
separation, time measurement and level 0 trigger. The ...experimental requirements for this detector are: a muon contamination in pion samples lower than 5×10
−3 in the momentum range 15–35
GeV/
c and a time resolution on the charged track better than 100
ps. A prototype of such a detector was built and tested in 2009; it consists of a full length (
≈
18
m
) Ne filled vessel equipped with a spherical mirror and 414 PMs on its focal plane, located about 17
m upstream of the mirror. This prototype was tested at CERN SPS on a positive hadron beam, in the required momentum range, to measure the
π
/
μ
separation and to confirm the time resolution obtained with a previous prototype; the
μ
misidentification probability is about 0.7% and the time resolution is better than 100
ps in the whole momentum range.
Capillary electrophoresis (CE) interfaced to mass spectrometry (MS) with electrospray ionization typically incorporates acidic additives or organic solvents to assist in ionization. Vibrating ...sharp-edge spray ionization (VSSI) is a voltage-free method to interface CE and MS that does not require these additives, making it appealing for protein analyses. CE-VSSI nanoflow sheath separations are performed with low ionic strength aqueous solutions in the sheath to reduce suppression. Serine is also included in the sheath to reduce analyte adduction. Proteins are detected in the 2.5-10 µM range, corresponding to an injected mass range of 0.1-1.2 ng. The anionic proteins β-lactoglobulin and transferrin are resolved using an unmodified fused silica capillary because they do not exhibit nonspecific surface adsorption. Conversely, separations of cationic proteins cytochrome c, ribonuclease A, and α-chymotrypsinogen A in an unmodified capillary require acidic background electrolytes to overcome adsorption. Alternatively, a semipermanent coating comprised self-assembled lipids overcomes surface adsorption at a neutral pH. Separations with zwitterionic and hybrid cationic coatings are complete within 15 or 6 min, respectively. The dimeric form of triosephosphate isomerase was observed at a 60 µM, corresponding to a mass of 19 ng, by dropping the temperature of the MS inlet.
Construction and test of a RICH prototype for the NA62 experiment Anzivino, G.; Biino, C.; Bizzeti, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2008, Volume:
593, Issue:
3
Journal Article
Peer reviewed
A RICH prototype has been constructed and tested. The detector was cylindrical, 17
m long and 60
cm diameter, filled with neon gas at atmospheric pressure. A spherical mirror with 17
m focal length ...was used and 96 photomultipliers were placed in the mirror focal plane. The prototype was exposed to a
200
GeV
/
c
momentum negative beam derived from the CERN SPS in the 2007 fall. The performances of the detector in terms of Cherenkov angle resolution, number of photoelectrons and time resolution are presented.
Fractal geometry was deployed to analyse water retention curves (WRC). The three models used to estimate the curves were the general pore‐solid fractal (PSF) model and two specific cases of the PSF ...model: the Tyler & Wheatcraft (TW) and the Rieu & Sposito (RS) models. The study was conducted on 30 undisturbed, sandy loam soil samples taken from a field and subjected to laboratory analysis. The fractal dimension, a non‐variable scale factor characterizing each water retention model proposed, was estimated by direct scaling. The method for determining the fractal dimension proposed here entails limiting the analysis to the interval between an upper and lower pressure head cut‐off on a log‐log plot, and defining the dimension itself as the straight regression line that interpolates the points in the interval with the largest coefficient of determination, R2. The scale relative to the cut‐off interval used to determine the fractal behaviour in each model used is presented. Furthermore, a second range of pressure head values was analysed to approximate the fractal dimension of the pore surface. The PSF model exhibited greater spatial variation than the TW or RS models for the parameter values typical of a sandy loam soil. An indication of the variability of the fractal dimension across the entire area studied is also provided.
Objectives: The fit of implant‐supported single‐tooth Lava zirconia assemblies was investigated in this study. The implant–abutment interface, the interface between the metallic and the zirconia ...portion of the abutment and the interface between Lava abutments and copings were evaluated. The adaptation of titanium abutments to implants and Lava copings was investigated as a control.
Material and methods: Twenty implants were randomly assigned and connected to Lava abutments (group 1) or titanium abutments (group 2). All specimens were subjected to scanning electron microscopy (SEM) analysis of the fixture/abutment fit. Afterwards, specimens were luted to Lava copings and subjected to a SEM evaluation of the marginal external adaptation of the abutments with the copings. Finally, the samples were embedded in resin, sectioned and subjected to SEM analysis of the following interfaces; group 1: titanium/zirconia interface (between the constitutive components of the Lava abutment) and the zirconia/zirconia interface (between the Lava abutment and the coping); group 2: the titanium/zirconia interface (between the titanium abutment and the Lava coping). Non‐parametric analysis of variance and a post hoc test were used for statistical analysis.
Results: Significant differences emerged in the cement thickness between titanium and zirconia components of the Lava abutments as compared with the thickness measured at the interface between Lava copings and the abutments investigated. No differences were found in cement thickness between Lava copings and the two different abutments.
Conclusions: When Lava abutments are used, the most critical cement thickness is the internal interface between its titanium and zirconia components. Lava coping adaptation for both Lava and titanium abutments is within the clinical acceptable range.
To cite this article:
Apicella D, Veltri M, Chieffi N, Balleri P, Ferrari M. Cement thickness at implant‐supported single‐tooth Lava assemblies: a scanning electron microscopic investigation. Clin. Oral Impl. Res. 21, 2010; 747–750. doi: 10.1111/j.1600‐0501.2009.01882.x
The study population consisted of 14 shoulders in 13 consecutive patients with surgically confirmed isolated subscapularis tendon tears. In all but three patients, the mechanism of injury was ...traumatic hyperextension or external rotation of the abducted arm. All patients reported pain and weakness in the affected shoulder. Physical findings revealed limited passive range of motion at maximal internal and external rotation due to pain, weakness of internal rotation of the shoulder, and tenderness in the region of the intertubercular groove. However, these findings did not conclusively point to the subscapularis tendon as the site of injury. Preoperative interpretation of magnetic resonance imaging studies was used to diagnose tears of the subscapularis tendon in 14 shoulders and biceps tendon subluxation or dislocation in 6 shoulders. On arthroscopic examination, one patient was found to have a partial-thickness tear that was treated with arthroscopic debridement. Six shoulders had full-thickness tears of the subscapularis tendon, and seven shoulders had full-thickness tears associated with concomitant biceps tendon pathologic conditions, including subluxation, dislocation, or rupture. The full-thickness subscapularis tendon tears were repaired via an open anterior approach to the shoulder through the deltopectoral groove. Associated biceps tendon injuries were treated with tenodesis of the tendon to the intertubercular groove. Our early followup results have shown that, with proper diagnoses and surgical treatments, patients have greatly decreased pain and marked improvement in shoulder function.
The role of the posterolateral and cruciate ligaments in restraining knee motion was studied in 11 human cadaveric knees. The posterolateral ligaments sectioned included the lateral collateral and ...arcuate ligaments, the popliteofibular ligament, and the popliteal tendon attachment to the tibia. Combined sectioning of the anterior cruciate and posterolateral ligaments resulted in maximal increases in primary anterior and posterior translations at 30 degrees of knee flexion. Primary varus, primary internal, and coupled external rotation also increased and were maximal at 30 degrees of knee flexion. Combined sectioning of the posterior cruciate and posterolateral ligaments resulted in increased primary posterior translation, primary varus and external rotation, and coupled external rotation at all angles of knee flexion. Examination of the knee at 30 degrees and 90 degrees of knee flexion can discriminate between combined posterior cruciate ligament and posterolateral injury and isolated posterolateral injury. The standard external rotation test performed at 30 degrees of knee flexion may not be routinely reliable for detecting combined anterior cruciate and posterolateral ligament injury. However, measurements of primary anterior-posterior translation, primary varus rotation, and coupled external rotation may be used to detect combined anterior cruciate and posterolateral ligament injury.
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