The Enumeration of Permutations with a Prescribed Number of “Forbidden” Patterns

We initiate a general approach for the fast enumeration of permutations with a prescribed number of occurrences of “forbidden” patterns that seems to indicate that the enumerating sequence is always P-recursive. We illustrate the method completely in terms of the patterns “abc,” “cab,” and “abcd.”     

The gravitational contribution to the momentum of a medium in general relativity

The time-space components of the macroscopic stress-energy tensor of a medium in general relativity (derived in a previous paper) are examined for the momentum density and energy flux of the microscopic gravitational fields. Agreement with both the Newtonian approximation and Chandrasekhar's post-Newtoninan approximation is noted.     

Urinary levoglucosan as a biomarker for residential wood smoke exposure

As part of a randomised controlled residential intervention study, levoglucosan (LG) was investigated as a biomarker for wood smoke exposure. This study was conducted among 33 children living in homes that used wood stoves for residential heating. Indoor fine particulate matter (PM_2.5) concentrations and corresponding urine samples from participants were collected during pre- and a post-intervention winter sampling periods. Interventions included the installation of an air filtration unit and a wood stove change out. Homes and children assigned to a placebo filter served as the control condition. Results showed a strong reduction in indoor PM_2.5 among the air filter homes (≈58% reduction), whereas the wood stove change out homes did not have a significant PM_2.5 reduction from pre- to post-intervention observations. Children living in the air filter homes did not show a corresponding reduction in urinary LG concentrations. Further analysis did not show an association between overall changes in indoor PM_2.5 concentrations and changes in urinary LG concentrations. These findings suggest that urinary LG is not a reliable indicator of wood smoke exposure in residential wood heating settings.     

An alternative synthesis of the lipophilic tail portion of abediterol using linear-selective hydroformylation

Abediterol is a compound currently in development for the treatment of respiratory disease at AstraZeneca. In this work we employ hydroformylation, an under-utilised reaction in the synthesis of pharmaceutical intermediates, as a key step to access the lipophilic amine portion of this molecule. The route described herein addresses some of the issues identified in the original route. Namely, hazardous materials are avoided and increased levels of control – from a process chemistry point of view – are demonstrated, with isolation of intermediates possible at multiple points in the synthesis. This work provides ‘proof-of-concept’ for an alternative synthetic route and provides high-quality material using a series of robust transformations.     

Determination of Citrus aurantium protoalkaloids using HPLC with acidic potassium permanganate chemiluminescence detection

Acidic potassium permanganate chemiluminescence was explored as a sensitive and selective mode of detection for phenolic phenethylamines (adrenergic amines) in consumer products containing Citrus aurantium extracts. Nine commercially available weight-loss products were analysed using rapid reversed-phase chromatography with a monolithic column (separation time of 4 min). The results were in good agreement with package labelling, with some notable exceptions. The products contained a wide concentration range of synephrine and total adrenergic amines, and the difference in consumer intake was even greater when the manufacturers’ recommended daily consumption was considered. The quantity of the extract, often specified on the packaging as equivalent grams of dry C. aurantium fruit, was a poor indicator of the concentration of the active ingredients. Methionine, a thioether amino acid contained in some weight-loss products, was identified as a potential interferent for this mode of detection.     

New Upper Bounds for the Connective Constants of Self-Avoiding Walks

Using a novel implementation of the Goulden–Jackson method, we compute new rigorous upper bounds for the connective constants of self-avoiding walks, breaking Alm's previous records for rectangular (hypercubic) lattices. We also give the explicit generating functions for memory 8. We then incorporate a numerical limit which gives bounds that are even better.     

Calculational demonstration that averaging enhances data for use in a LEED analysis

Representative LEED I-V profiles have been calculated corresponding to the incident beam slightly misaligned from, and exactly aligned with, the surface normal. It is demonstrated that the average profile, obtained by taking the mean of the {ij} set of profiles for the misaligned case, has excellent agreement with the (ij) profile calculated for exactly normal incidence. Thus, it is inferred that using the mean of a set of experimental {ij} profiles measured at “normal incidence” in a LEED analysis reduces the effects of those errors caused by beam divergence, beam misalignment, and some variations in surface topography.