Upper atmosphere chemical release study Final report

Chemical release experiments to study upper atmosphere including night sky oxygen emissio

pH-independent immediate release polymethacrylate formulations : an observational study

Using Eudragit (R) E PO (EudrE) as a polymethacrylate carrier, the aim of the study was to develop a pH-independent dosage form containing ibuprofen (IBP) as an active compound via chemical modification of the polymer (i.e. quaternization of amine function) or via the addition of dicarboxylic acids (succinic, glutaric and adipic acid) to create a pH micro-environment during dissolution. Biconvex tablets (diameter: 10mm; height: 5mm) were produced via hot melt extrusion and injection molding. In vitro dissolution experiments revealed that a minimum of 25% of quaternization was sufficient to partially (up to pH 5) eliminate the pH-dependent effect of the EudrE/IBP formulation. The addition of dicarboxylic acids did not alter IBP release in a pH 1 and 3 medium as the dimethyl amino groups of EudrE are already fully protonated, while in a pH 5 solvent IBP release was significantly improved (cf. from 0% to 92% release after 1h dissolution experiments upon the addition of 20wt.% succinic acid). Hence, both approaches resulted in a pH-independent (up to pH 5) immediate release formulation. However, the presence of a positively charged polymer induced stability issues (recrystallization of API) and the formulations containing dicarboxylic acids were classified as mechanically unstable. Hence, further research is needed to obtain a pH-independent immediate release formulation while using EudrE as a polmethacrylate carrier

Fabrication and Characterization of Electrospun Drug-eluting Nanofibers from Polycaprolactone/Chitosan Blends

Electrospinning has emerged as a widely accepted technique with ability to produce nanofibers that can be employed in many biomedical applications. In particular, drug-eluting nanofibers have become very popular in controlled release of small molecule drugs. In this study, nanofibers from blends of polylactocaprone (PCL) and chitosan (CHI) were electrospun with the ability to load a model drug, acetylsalicylic acid (ASA), at 10 wt%. PCL/CHI fibers exhibited smooth surface morphology at polymer compositions ranging from 100/0 to 40/60 with or without the incorporation of ASA. Mechanical properties suggested a brittle failure mechanism for fibers loaded with drug. In vitro drug release study displayed a controlled release profile of ASA up to 48 h. Our study aims to explore the drug-polymer interactions and their effects on fiber structure, mechanical properties and drug release profile.Cockrell School of Engineerin

Trends and uptake of new formulations of controlled-release oxycodone in Canada

Purpose: This study investigated the impact of changing availability of tamper‐deterrent and non‐tamper‐deterrent oxycodone on prescribing patterns of controlled‐release oxycodone across Canada. Methods: We conducted a population‐based, serial cross‐sectional study of controlled‐release oxycodone dispensing from community pharmacies across Canada between October 2007 and April 2016. We calculated rates of dispensing (tablets per 100 population) and reported the relative market share of generic non‐tamper‐deterrent controlled‐release oxycodone. All analyses were reported nationally and stratified by province. Results: After the introduction of a tamper‐deterrent formulation, the national rate of controlled‐release oxycodone dispensing fell by 44.6% (from 26.4 to 14.6 tablets per 100 population from February 2012 to April 2016). Between December 2012 and July 2013, there was moderate uptake of generic non‐tamper‐deterrent controlled‐release oxycodone (968 452 tablets; 16.0% in July 2013), which appeared to have little impact on the overall rate of controlled‐release oxycodone dispensing in Canada. However, the uptake of generic non‐tamper‐deterrent oxycodone varied considerably by province. By April 2016, 55.0% of all controlled‐release oxycodone tablets dispensed in Quebec were for the generic formulation. […

The dynamics of single spike-evoked adenosine release in the cerebellum

The purine adenosine is a potent neuromodulator in the brain, with roles in a number of diverse physiological and pathological processes. Modulators such as adenosine are difficult to study as once released they have a diffuse action (which can affect many neurones) and, unlike classical neurotransmitters, have no inotropic receptors. Thus rapid postsynaptic currents (PSCs) mediated by adenosine (equivalent to mPSCs) are not available for study. As a result the mechanisms and properties of adenosine release still remain relatively unclear. We have studied adenosine release evoked by stimulating the parallel fibres in the cerebellum. Using adenosine biosensors combined with deconvolution analysis and mathematical modelling, we have characterised the release dynamics and diffusion of adenosine in unprecedented detail. By partially blocking K+ channels, we were able to release adenosine in response to a single stimulus rather than a train of stimuli. This allowed reliable sub-second release of reproducible quantities of adenosine with stereotypic concentration waveforms that agreed well with predictions of a mathematical model of purine diffusion. We found no evidence for ATP release and thus suggest that adenosine is directly released in response to parallel fibre firing and does not arise from extracellular ATP metabolism. Adenosine release events showed novel short-term dynamics, including facilitated release with paired stimuli at millisecond stimulation intervals but depletion-recovery dynamics with paired stimuli delivered over minute time scales. These results demonstrate rich dynamics for adenosine release that are placed, for the first time, on a quantitative footing and show strong similarity with vesicular exocytosis

Movement, Dispersion, and Orientation of a Population of the Colorado Potato Beetle, \u3ci\u3eLeptinotarsa Decemlineata\u3c/i\u3e (Coleoptera: Chrysomelidae), in Eggplant

Short-term dispersal, dispersion, and orientation of a population of the Colorado potato beetle, Leptinotarsa decemlineata. were examined in a uniformly spaced planting of eggplant using a mark-recapture technique. Recaptures of marked beetles declined throughout the study, the greatest decline occurring 24 h after release. Dispersal of remaining beetles through the field was gradual; beetle numbers declined with distance from the release point during the first 3 days of the study and increased with distance thereafter. Beetles were highly aggregated for 3-4 days after release but were well dispersed for the remainder of the study. Dispersal of aggregated beetles may have been stimulated by host plant defoliation. Orientation of dispersing beetles was significantly nonrandom for the majority of the study. Beetles oriented predominantly east-northeast

Racial Disparities and Similarities in Post-Release Recidivism and Employment Among Ex-prisoners with a Different Level of Education

Previous studies rarely examined racial disparities in post-release employment and recidivism. Finding a job is an immediate challenge to all released ex-prisoners, and often more difficult for African American ex-prisoners who typically return to economically-depressed neighborhoods upon release from prison. The present researchers conducted a 5-year (2005-2009) follow-up study in an attempt to understand racial disparities in post-release employment and recidivism among 6,394 released ex-prisoners (2,531 Caucasian and 3,863 African American), while controlling for the ex-prisoner’s level of education. Results of this study showed that African American ex-prisoners had a higher unemployment rate and recidivism rate than Caucasian ex-prisoners. This study also revealed that released ex-prisoners, if employed, would likely be under-employed and experience difficulties in sustaining employment, regardless of the ex-prisoner’s ethnicity. Most importantly, post-release employment and level of education were the two most influential predictors to recidivism among ex-prisoners, regardless of ethnicity

Evaluation of gellan gum fluid gels as modified release oral liquids

Oral liquids are often preferred for drug administration to patients for whom swallowing is difficult, however formulating modified release versions can be challenging. A potential route to achieve modified release in oral liquids is by using fluid (sheared) gels formed by introducing a shear field during gelation in gel-forming biopolymers. These fluid gels can act as pourable viscoelastic fluids but retain true gel micro/nano structure. Here, we have demonstrated that fluid gels have potential as paediatric oral liquids preventing release of ibuprofen in simulated gastric fluid. Subsequent release at pH 7.4 was affected by the duration of exposure and magnitude of acid pH with a linear relationship between onset of release and the preceding acidic exposure duration. Delayed release was a result of increasing gel stiffness, a consequence of the acidity of the initial release media and exposure time. A much faster release rate was measured when exposure time in acid was 10 min compared with 60 min. This study highlights the potential to design fluid gels that are tuned to have a specified stiffness at a particular pH and exposure time. This could enable the preparation oral liquids with modified release behaviour

Translocation and post-release monitoring techniques of Auckland green gecko (Naultinus elegans elegans) using a penned release : a thesis in partial fulfilment of the requirements for the degree of Master of Science in Conservation Biology, Massey University, Auckland, New Zealand

A translocation of Auckland green gecko (Naultinus elegans elegans) using penned and hard releases is conducted during an emergency salvage in the Hunua Ranges, Auckland. The value of limiting individuals’ movement post-translocation is discussed. Radio-telometry as a resourceful long-term monitoring technique is also discussed including limitations.. The population of 52 individuals were salvaged prior to deforestation of habitat as part of the mitigation process in human-wildlife conflict. Translocations are a major part of New Zealand’s conservation strategies, and this event proved a unique opportunity to study post-release movements of Auckland green gecko (Naultinus elegans elegans). To test whether penned releases have an effect on post-release movements, salvaged geckos were divided into two groups. One group of individuals was released as a penned release and one group as a non-penned (hard) release. Using radio-telemetry, information was collected on movement behaviours post-release. 100% minimum convex polygons and 95% kernel estimates were used to establish areas for each individual and compared between the two release groups. Due to the small sample sizes, statistical power was low and no statistically significant differences were found between penned and non-penned release groups in terms of movement post-release. However, exploratory data analysis shows some differences in range particularly in relation to distance from release (m). It seems that penned released geckos tend to stay within the area of their release site compared with non-penned released geckos. This could be an early indication of territory and home range establishment from founder individuals. Multiple methods of monitoring post-translocation of green geckos as well as trapping and monitoring or mammalian predators within the area were carried out throughout the duration of the radio-telemetry aspect of the study. The benefits and limitations are discussed for each. Rat trapping in the release site area showed a trend with very low numbers caught (n=2) and high levels of mice prints throughout the general shrubland area. The presence of rat posion in the digestive tract of one rat caught during trapping leans towards successful pest control to date which is keeping numbers of rats at relatively low densities. Using penned release methods during wildlife translocations can prove to be an expensive and long-term endeavour. The practical use of penning Auckland green gecko post-release is still yet to be accurately defined in this study. Using radio tracking techniques to monitor the translocated individuals’ movement behaviours up to 4 weeks after release was successful. Using specific materials and harness designs that are the right ‘fit’ for the species is imperative as was shown with the unsuccessful use of the first design in this study. Transmitters allowed for the collection of detailed information of movement behaviours horizontal and vertical to be collected with ease. For cryptic, arboreal geckos this information would otherwise be difficult to attain if relying only on regular searching techniques such as spotlighting. Future translocations of gecko should consider using radio-telemetry to collect invaluable information for future translocation management decisions

Design of a new type of coating for the controlled release of heparin

Thrombus formation at the surface of blood contacting devices can be prevented by local release of heparin. Preferably, the release rate should be constant for prolonged periods of time. The minimum heparin release rate to achieve thromboresistance will be different for various applications and should therefore be adjustable. In this study a new type of heparin release system is presented which may be applied as a coating for blood contacting devices. The system is based on the covalent immobilization of heparin onto porous structures via hydrolysable bonds. This approach was evaluated by the immobilization of heparin onto a porous cellulosic substrate via ester bonds. Cuprophan was used as a model substrate and N,N¿-carbonyldiimidazole as a coupling agent. Heparinized Cuprophan incubated in phosphate buffered saline showed a release of heparin due to the hydrolysis of the ester bonds between heparin and Cuprophan. The release rate could be easily adjusted by varying the amount of coupling agent used during immobilization. Cuprophan with a rather stable heparin coating (release rate: 6.1 mU/cm2·h) and Cuprophan which shows a substantial release of heparin (release rate up to 23.0 mU/cm2·h) could be prepared. Except when the release was relatively high, release rates were constant for at least 1 week. Storage of the release system at ambient conditions up to 6 months or sterilization by means of steam, ethylene oxide exposure, or gamma irradiation did not affect the release properties. It was concluded that this concept for a heparin release system is highly promising to prepare thromboresistant surfaces for various blood contacting devices