Characterization of Individual Nanoparticles and Applications of Nanoparticles in Mass Spectrometry

The chemical characterization of individual nanoparticles (NPs) </= 100 nm in diameter is one of the current frontiers in analytical chemistry. We present here, a methodology for the characterization of individual NPs by obtaining molecular information from single massive cluster impacts. The clusters used in this secondary ion mass spectrometry (SIMS) technique are Au4004+ and C60+. The ionized ejecta from each impact are recorded individually which allows to identify ions emitted from a surface volume of ~10 nm in diameter and 5-10 nm in depth. The mode of analyzing ejecta individually from each single cluster impact gives insight into surface homogeneity, in our case NPs and their immediate surroundings. We show that when the NPs (50 nm Al) are larger than the size of the volume perturbed by the projectile, the secondary ion emission (SI) resembles that of a bulk surface. However, when the NP (5 nm Ag) is of the size range of the volume perturbed by projectile the SI emission is different from that of a bulk surface. As part of this sub-assay volume study, the influence of neighboring NP on the SI emission was examined by using a mixture of different types of NPs (5 nm Au and 5 nm Ag). The methodology of using cluster SIMS via a sequence of stochastic single impacts yield information on the surface coverage of the NPs, as well as the influence of the chemical environment on the type of SI emission. We also present a case of soft landing NPs for laser desorption ionization mass spectrometry. NPs enhance the SI emission in a manner that maintains the integrity of the spatial distribution of molecular species. The results indicate that the application can be extended to imaging mass spectrometry

The development and validation of a scoring tool to predict the operative duration of elective laparoscopic cholecystectomy

Background: The ability to accurately predict operative duration has the potential to optimise theatre efficiency and utilisation, thus reducing costs and increasing staff and patient satisfaction. With laparoscopic cholecystectomy being one of the most commonly performed procedures worldwide, a tool to predict operative duration could be extremely beneficial to healthcare organisations. Methods: Data collected from the CholeS study on patients undergoing cholecystectomy in UK and Irish hospitals between 04/2014 and 05/2014 were used to study operative duration. A multivariable binary logistic regression model was produced in order to identify significant independent predictors of long (> 90 min) operations. The resulting model was converted to a risk score, which was subsequently validated on second cohort of patients using ROC curves. Results: After exclusions, data were available for 7227 patients in the derivation (CholeS) cohort. The median operative duration was 60 min (interquartile range 45–85), with 17.7% of operations lasting longer than 90 min. Ten factors were found to be significant independent predictors of operative durations > 90 min, including ASA, age, previous surgical admissions, BMI, gallbladder wall thickness and CBD diameter. A risk score was then produced from these factors, and applied to a cohort of 2405 patients from a tertiary centre for external validation. This returned an area under the ROC curve of 0.708 (SE = 0.013, p  90 min increasing more than eightfold from 5.1 to 41.8% in the extremes of the score. Conclusion: The scoring tool produced in this study was found to be significantly predictive of long operative durations on validation in an external cohort. As such, the tool may have the potential to enable organisations to better organise theatre lists and deliver greater efficiencies in care

Quality of reporting in randomized trials published in high-quality surgical journals

Background: Randomized controlled trials (RCTs) in surgery can provide valuable evidence of the efficacy of interventions if they are well-designed, appropriately executed, and adequately reported. Adequate reporting of methodology in surgical RCTs is known to be poor, and adverse-event reporting in surgical research is inconsistent. The Consolidated Standards of Reporting Trials (CONSORT) statement is a framework to help authors report their findings in a transparent manner. Extensions to the CONSORT statement have been published recently to address deficiencies in adverse-event reporting and in reporting of specific criteria related to nonpharmacologic treatments. The aim of this study was to assess the quality of reporting of trial methodology and adverse events in a sample of general surgical RCTs published in high-quality surgical journals using the criteria specified in the CONSORT statements.Study Design: We used impact factor to identify the top three ranked surgical journals in 2004. We then obtained information on all RCTs published in these journals in the 2005 calendar year. We assessed quality of reporting using Jadad score, compared the quality of RCTs from CONSORT-endorsing journals with nonendorsers, and assessed the number of RCTs adequately reporting key generic methodologic, adverse-event?related, and specific nonpharmacologic criteria.Results: Of 42 RCTs analyzed, only 40% (17 of 42) had a Jadad score ?3. There was no significant difference in the number of high-quality RCTs published in CONSORT-endorsing journals compared with nonendorsers (p = 0.3). The median percentage of RCTs adequately reporting generic methodologic, adverse-event?related, and specific nonpharmacologic criteria was 32.5%, 17%, and 36.5%, respectively.Conclusions: Quality of reporting of generic methodologic, adverse-event?related, and specific nonpharmacologic criteria in surgical RCTs is poor. Increased attention to quality of reporting of surgical RCTs is required if studies are to meet published criteria.<br/