Application of bag sampling technique for particle size distribution measurements

Bag sampling techniques can be used to temporarily store an aerosol and therefore provide sufficient time to utilize sensitive but slow instrumental techniques for recording detailed particle size distributions. Laboratory based assessment of the method were conducted to examine size dependant deposition loss coefficients for aerosols held in VelostatTM bags conforming to a horizontal cylindrical geometry. Deposition losses of NaCl particles in the range of 10 nm to 160 nm were analysed in relation to the bag size, storage time, and sampling flow rate. Results of this study suggest that the bag sampling method is most useful for moderately short sampling periods of about 5 minutes

Transformation pathways of 2,2-dimethyloxirane on aluminosilicates: the effects of catalyst structure and reaction conditions

The ring transformation reactions of 2,2-dimethyloxirane were studied over various aluminosilicates (HZSM-5, CuZSM-5, HY, AIMCM-41 or NaNa-loaded A1MCM-41) in a pulse reactor at 423 K. The main reactions identified were isomerisation and cyclic dimerisation. The product formation selectivities could be tuned by varying the pore size of the molecular sieves and/or altering the reaction parameters. Large pore size and mild conditions favoured isomerisation, while an optimally constrained environment and overloading the catalyst with the epoxide (increased pulse size) was advantageous for cyclic dimerisation

A sampling strategy for longitudinal and cross-sectional analyses using a large national claims database

ImportanceThe United States (US) Medicare claims files are valuable sources of national healthcare utilization data with over 45 million beneficiaries each year. Due to their massive sizes and costs involved in obtaining the data, a method of randomly drawing a representative sample for retrospective cohort studies with multi-year follow-up is not well-documented.ObjectiveTo present a method to construct longitudinal patient samples from Medicare claims files that are representative of Medicare populations each year.DesignRetrospective cohort and cross-sectional designs.ParticipantsUS Medicare beneficiaries with diabetes over a 10-year period.MethodsMedicare Master Beneficiary Summary Files were used to identify eligible patients for each year in over a 10-year period. We targeted a sample of ~900,000 patients per year. The first year's sample is stratified by county and race/ethnicity (white vs. minority), and targeted at least 250 patients in each stratum with the remaining sample allocated proportional to county population size with oversampling of minorities. Patients who were alive, did not move between counties, and stayed enrolled in Medicare fee-for-service (FFS) were retained in the sample for subsequent years. Non-retained patients (those who died or were dropped from Medicare) were replaced with a sample of patients in their first year of Medicare FFS eligibility or patients who moved into a sampled county during the previous year.ResultsThe resulting sample contains an average of 899,266 ± 408 patients each year over the 10-year study period and closely matches population demographics and chronic conditions. For all years in the sample, the weighted average sample age and the population average age differ by <0.01 years; the proportion white is within 0.01%; and the proportion female is within 0.08%. Rates of 21 comorbidities estimated from the samples for all 10 years were within 0.12% of the population rates. Longitudinal cohorts based on samples also closely resembled the cohorts based on populations remaining after 5- and 10-year follow-up.Conclusions and relevanceThis sampling strategy can be easily adapted to other projects that require random samples of Medicare beneficiaries or other national claims files for longitudinal follow-up with possible oversampling of sub-populations

HelicoVax: Epitope-based therapeutic \u3ci\u3eHelicobacter pylori\u3c/i\u3e vaccination in a mouse model

Helicobacter pylori is the leading cause of gastritis, peptic ulcer disease and gastric adenocarcinoma and lymphoma in humans. Due to the decreasing efficacy of anti-H. pylori antibiotic therapy in clinical practice, there is renewed interest in the development of anti-H. pylori vaccines. In this study an in silico-based approach was utilized to develop a multi-epitope DNA-prime/peptide-boost immunization strategy using informatics tools. The efficacy of this construct was then assessed as a therapeutic vaccine in a mouse model of gastric cancer induced by chronic H. pylori infection. The multi-epitope vaccine administered intranasally induced a broad immune response as determined by interferon-gamma production in ELISpot assays. This was associated with a significant reduction in H. pylori colonization compared with mice immunized with the same vaccine intramuscularly, given an empty plasmid, or given a whole H. pylori lysate intranasally as the immunogen. Total scores of gastric histological changes were not significantly different among the 4 experimental groups. These results suggest that further development of an epitope-based mucosal vaccine may be beneficial in eradicating H. pylori and reducing the burden of the associated gastric diseases in humans

Noncovalent Functionalization of Graphene and Graphene Oxide for Energy Materials, Biosensing, Catalytic, and Biomedical Applications

This Review focuses on noncovalent functionalization of graphene and graphene oxide with various species involving biomolecules, polymers, drugs, metals and metal oxide-based nanoparticles, quantum dots, magnetic nanostructures, other carbon allotropes (fullerenes, nanodiamonds, and carbon nanotubes), and graphene analogues (MoS2, WS2). A brief description of pi-pi interactions, van der Waals forces, ionic interactions, and hydrogen bonding allowing noncovalent modification of graphene and graphene oxide is first given. The main part of this Review is devoted, to tailored functionalization for applications in drug delivery, energy materials, solar cells, water splitting, biosensing, bioimaging, environmental, catalytic, photocatalytic, and biomedical technologies. A significant part of this Review explores the possibilities of graphene/graphene oxide-based 3D superstructures and their use in lithium-ion batteries. This Review ends with a look at challenges and future prospects of noncovalently modified graphene and graphene oxideope

Whole-Genome Immunoinformatic Analysis of F. tularensis: Predicted CTL Epitopes Clustered in Hotspots Are Prone to Elicit a T-Cell Response

The cellular arm of the immune response plays a central role in the defense against intracellular pathogens, such as F. tularensis. To date, whole genome immunoinformatic analyses were limited either to relatively small genomes (e.g. viral) or to preselected subsets of proteins in complex pathogens. Here we present, for the first time, an unbiased bacterial global immunoinformatic screen of the 1740 proteins of F. tularensis subs. holarctica (LVS), aiming at identification of immunogenic peptides eliciting a CTL response. The very large number of predicted MHC class I binders (about 100,000, IC50 of 1000 nM or less) required the design of a strategy for further down selection of CTL candidates. The approach developed focused on mapping clusters rich in overlapping predicted epitopes, and ranking these “hotspot” regions according to the density of putative binding epitopes. Limited by the experimental load, we selected to screen a library of 1240 putative MHC binders derived from 104 top-ranking highly dense clusters. Peptides were tested for their ability to stimulate IFNγ secretion from splenocytes isolated from LVS vaccinated C57BL/6 mice. The majority of the clusters contained one or more CTL responder peptides and altogether 127 novel epitopes were identified, of which 82 are non-redundant. Accordingly, the level of success in identification of positive CTL responders was 17–25 fold higher than that found for a randomly selected library of 500 predicted MHC binders (IC50 of 500 nM or less). Most proteins (ca. 2/3) harboring the highly dense hotspots are membrane-associated. The approach for enrichment of true positive CTL epitopes described in this study, which allowed for over 50% increase in the dataset of known T-cell epitopes of F. tularensis, could be applied in immunoinformatic analyses of many other complex pathogen genomes