Automatic and unbiased assessment of competence in colonoscopy:exploring validity of the Colonoscopy Progression Score (CoPS)

Background and aims: Colonoscopy is a difficult procedure to master. Increasing demands for colonoscopy, due to screening and surveillance programs, have highlighted the need for competent performers. Valid methods for assessing technical skills are pivotal for training and assessment. This study is the first clinical descriptive report of a novel colonoscopy assessment tool based on Magnetic Endoscopic Imaging (MEI) data and the aim was to gather validity evidence based on the data collected using the “Colonoscopy Progression Score” (CoPS). Methods: We recorded 137 colonoscopy procedures performed by 31 endoscopists at three university hospitals. The participants performed more than two procedures each (range 2 – 12) and had an experience of 0 – 10 000 colonoscopies. The CoPS was calculated for each recording and validity was explored using a widely accepted contemporary framework. The following sources of validity evidence were explored: response process (data collection), internal structure (reliability), relationship to other variables (i. e. operator experience), and consequences of testing (pass/fail). Results: Identical set-ups at all three locations ensured uniform data collection. The Generalizability coefficient (G-coefficient) was 0.80, and a Decision-study (D-study) revealed that four recordings were sufficient to ensure a G-coefficient above 0.80. We showed a positive correlation between CoPS and experience with Pearson’s r of 0.61 (P < 0.001). A pass/fail standard of 107 points was established using the contrasting group method to explore the consequences of testing. Conclusion: This study provides evidence supporting the validity of the CoPS for use in assessing technical colonoscopy performance in the clinical setting. Study registration: NCT01997177

Laser-induced rotation of iodine molecules in He-nanodroplets: revivals and breaking-free

Rotation of molecules embedded in He nanodroplets is explored by a combination of fs laser-induced alignment experiments and angulon quasiparticle theory. We demonstrate that at low fluence of the fs alignment pulse, the molecule and its solvation shell can be set into coherent collective rotation lasting long enough to form revivals. With increasing fluence, however, the revivals disappear -- instead, rotational dynamics as rapid as for an isolated molecule is observed during the first few picoseconds. Classical calculations trace this phenomenon to transient decoupling of the molecule from its He shell. Our results open novel opportunities for studying non-equilibrium solute-solvent dynamics and quantum thermalization.Comment: 6+7 pages; 4+1 figures; 1 tabl

Simulation-based training for colonoscopy:establishing criteria for competency

The aim of this study was to create simulation-based tests with credible pass/fail standards for 2 different fidelities of colonoscopy models. Only competent practitioners should perform colonoscopy. Reliable and valid simulation-based tests could be used to establish basic competency in colonoscopy before practicing on patients. Twenty-five physicians (10 consultants with endoscopic experience and 15 fellows with very little endoscopic experience) were tested on 2 different simulator models: a virtual-reality simulator and a physical model. Tests were repeated twice on each simulator model. Metrics with discriminatory ability were identified for both modalities and reliability was determined. The contrasting-groups method was used to create pass/fail standards and the consequences of these were explored. The consultants significantly performed faster and scored higher than the fellows on both the models (P < 0.001). Reliability analysis showed Cronbach α = 0.80 and 0.87 for the virtual-reality and the physical model, respectively. The established pass/fail standards failed one of the consultants (virtual-reality simulator) and allowed one fellow to pass (physical model). The 2 tested simulations-based modalities provided reliable and valid assessments of competence in colonoscopy and credible pass/fail standards were established for both the tests. We propose to use these standards in simulation-based training programs before proceeding to supervised training on patients

Display of wasp venom allergens on the cell surface of Saccharomyces cerevisiae

<p>Abstract</p> <p>Background</p> <p>Yeast surface display is a technique, where the proteins of interest are expressed as fusions with yeast surface proteins and thus remain attached to the yeast cell wall after expression. Our purpose was to study whether allergens expressed on the cell surface of baker's yeast <it>Saccharomyces cerevisiae </it>preserve their native allergenic properties and whether the yeast native surface glycoproteins interfere with IgE binding. We chose to use the major allergens from the common wasp <it>Vespula vulgaris </it>venom: phospholipase A1, hyaluronidase and antigen 5 as the model.</p> <p>Results</p> <p>The proteins were expressed on the surface as fusions with a-agglutinin complex protein AGA2. The expression was confirmed by fluorescent cytometry (FACS) after staining the cells with antibody against a C-tag attached to the C-terminal end of the allergens. Phospholipase A1 and hyaluronidase retained their enzymatic activities. Phospholipase A1 severely inhibited the growth of the yeast cells. Antigen 5 - expressing yeast cells bound IgE antibodies from wasp venom allergic patient sera but not from control sera as demonstrated by FACS. Moreover, antigen 5 - expressing yeast cells were capable of mediating allergen-specific histamine release from human basophils.</p> <p>Conclusions</p> <p>All the three major wasp venom allergens were expressed on the yeast surface. A high-level expression, which was observed only for antigen 5, was needed for detection of IgE binding by FACS and for induction of histamine release. The non-modified <it>S. cerevisiae </it>cells did not cause any unspecific reaction in FACS or histamine release assay despite the expression of high-mannose oligosaccharides.</p> <p>In perspective the yeast surface display may be used for allergen discovery from cDNA libraries and possibly for sublingual immunotherapy as the cells can serve as good adjuvant and can be produced in large amounts at a low price.</p

Strongly aligned molecules inside helium droplets in the near-adiabatic regime

Iodine (I$_2$) molecules embedded in He nanodroplets are aligned by a 160 ps long laser pulse. The highest degree of alignment, occurring at the peak of the pulse and quantified by $\langle \cos^2 \theta_{2D} \rangle$, is measured as a function of the laser intensity. The results are well described by $\langle \cos^2 \theta_{2D} \rangle$ calculated for a gas of isolated molecules each with an effective rotational constant of 0.6 times the gas-phase value, and at a temperature of 0.4 K. Theoretical analysis using the angulon quasiparticle to describe rotating molecules in superfluid helium rationalizes why the alignment mechanism is similar to that of isolated molecules with an effective rotational constant. A major advantage of molecules in He droplets is that their 0.4 K temperature leads to stronger alignment than what can generally be achieved for gas phase molecules -- here demonstrated by a direct comparison of the droplet results to measurements on a $\sim$ 1 K supersonic beam of isolated molecules. This point is further illustrated for more complex system by measurements on 1,4-diiodobenzene and 1,4-dibromobenzene. For all three molecular species studied the highest values of $\langle \cos^2 \theta_{2D} \rangle$ achieved in He droplets exceed 0.96.Comment: 11 pages, 8 figure