Application of middle-down approach in quantitation and catabolite identification of protein by LC-high-resolution mass spectrometry.

Aim: To further enhance the detection sensitivity and increase resolving power of top-down intact protein bioanalysis, middle-down approach was explored. Materials & methods: An monoclonal antibody (mAb) was used as a model protein to evaluate quantitative bioanalytical assay performance and a disulfide linked dimer protein was investigated for its pharmacokinetics properties and catabolism in vivo by middle-down approach. Results & Conclusion: For quantitation of the mAb, different subunits generated by middle-down approach provided different level of signal improvement in biological samples with Lc and half Fc giving five-times better sensitivity than intact mAb. For the dimer protein, middle-down analysis by reduction enabled effective differentiation of the unchanged protein and its oxidized form, and clearly elucidated their respective proteolytic catabolites.

Adolescent Marijuana Use, Marijuana-Related Perceptions, and Use of Other Substances Before and After Initiation of Retail Marijuana Sales in Colorado (2013-2015).

Due to the recentness of changes to marijuana policies in a number of states, the effect on adolescent use and perceptions is not yet well understood. This study examines change in adolescent marijuana use and related perceptions in Colorado, before and after the implementation of legal commercial sale of recreational marijuana for adults starting on January 1, 2014. The data are from a repeated cross-sectional survey of a representative sample of Colorado high school students, with separately drawn samples surveyed in fall 2013 (prior to implementation) and fall 2015 (18 months after implementation). We examined change in the prevalence of adolescent marijuana use, measured by lifetime use, past 30-day use, frequent use, and use on school property. To consider the possibility of heterogeneity in the change in marijuana use, we examined change in past 30-day marijuana use by demographic characteristics (sex, grade, race/ethnicity), school characteristics (poverty, percent minority), urbanicity of the school district, and whether the city or county permitted retail marijuana stores. There was an absence of significant effects for change in lifetime or past 30-day marijuana use. Among those reporting past 30-day use, frequent use and use on school property declined. There was a significant decline in the perceived harm associated with marijuana use, but we did not find a significant effect for perceived wrongfulness, perceived ease of access, or perceived parental disapproval. We did not find significant variability in past 30-day use by demographic characteristics or by school and community factors from 2013 to 2015. We did not find a significant effect associated with the introduction of legal sales of recreational marijuana to adults in Colorado on adolescent (illegal) use, but ongoing monitoring is warranted, including consideration of heterogeneity in the effects of marijuana policies.

Monitoring molecular mass transfer in cation-free nanoporous host crystals of type AlPO-LTA.

Micro-imaging is employed to monitor the evolution of intra-crystalline guest profiles during molecular adsorption and desorption in cation-free zeolites AlPO-LTA. The measurements are shown to provide direct evidence on the rate of intra-crystalline diffusion and surface permeation and their inter-relation. Complemented by PFG NMR and integral IR measurements, a comprehensive overview of the diffusivities of light hydrocarbons in this important type of host materials is provided.

Molecular-scale insights into the mechanisms of ionic liquids interactions with carbon nanotubes.

By means of fully atomistic molecular simulations we study basic mechanisms of carbon nanotube interactions with several different room temperature ionic liquids (RTILs) in their mixtures with acetonitrile. To understand the effects of the cation molecular geometry on the properties of the interface structure in the RTIL systems, we investigate a set of three RTILs with the same TFSI (bis (trifluoromethylsulfonyl)imide) anion but with different cations, namely, EMIm (1-ethyl-3-methylimidazolium), BMIm (1-butyl-3-methylimidazolium) and OMIm (1-octyl-3-methylimidazolium) ions. The cations have identical charged methylimidazolium 'heads' but different nonpolar alkyl 'tails' where the length of the tail increases from EMIm to OMIm. The analysis of the simulation data results in the following conclusions: There is an enrichment of all molecular components of ionic liquids under study at the CNT surface with formation of several distinct layers even at the non-charged CNT surface. Mixing RTIL with acetonitrile decreases ion-counterion correlations in the electric double layer. Increase of the length of the non-polar 'tail' of cations increases the propensity of imidazolium-based cations to lay parallel to the CNT surface. At the CNT cathode TFSI anions and molecular cations are preferentially oriented parallel to the surface. At the CNT anode the TFSI anions are oriented parallel to the surface, however the preferred orientations of cations depend on the length of non-polar tail: EMIm cations are oriented perpendicular to the surface, BMIm cations can be in both parallel as well as perpendicular orientations, OMIm cations are oriented parallel to the surface. As a result, by applying an electric potential on the CNT electrode and/or varying the structure of molecular ions it is possible to change molecular ion orientations at the surface and, consequently, the structure of the electrical double layer at the CNT-RTIL interface.

The German registry for natural orifice translumenal endoscopic surgery: report of the first 551 patients.

OBJECTIVE: To analyze patient outcome in the first 14 months of the German natural orifice translumenal endoscopic surgery (NOTES) registry (GNR). SUMMARY BACKGROUND DATA: NOTES is a new surgical concept, which permits scarless intra-abdominal operations through natural orifices, such as the mouth, vagina, rectum, or urethra. The GNR was established as a nationwide outcome database to allow the monitoring and safe introduction of this technique in Germany. METHODS: The GNR was designed as a voluntary database with online access. All surgeons in Germany who performed NOTES procedures were requested to participate in the registry. The GNR recorded demographical and therapy data as well as data on the postoperative course. RESULTS: A total of 572 target organs were operated in 551 patients. Cholecystectomies accounted for 85.3% of all NOTES procedures. All procedures were performed in female patients using transvaginal hybrid technique. Complications occurred in 3.1% of all patients, conversions to laparoscopy or open surgery in 4.9%. In cholecystectomies, institutional case volume, obesity, and age had substantial effect on conversion rate, operation length, and length of hospital stay, but no effect on complications. CONCLUSIONS: Despite the fact that NOTES has just recently been introduced, the technique has already gained considerable clinical application. Transvaginal hybrid NOTES cholecystectomy is a practicable and safe alternative to laparoscopic resection even in obese or older patients.

Manipulating ion-atom collisions with coherent electromagnetic radiation.

Laser-assisted ion-atom collisions are considered in terms of a nonperturbative quantum mechanical description of the electronic motion. It is shown for the system He(2+) - H at 2 keV/amu that the collision dynamics depend strongly on the initial phase of the laser field and the applied wavelength. Whereas electronic transitions are caused by the concurrent action of the field and the projectile ion at relatively low frequencies, they can be separated into modified collisional capture and field ionization events in the region above the one-photon ionization threshold.