The Effect of Sub- and Near-Critical Carbon Dioxide Assisted Manufacturing on Medical Thermoplastic Polyurethane.

Incorporating thermally labile active pharmaceutical ingredients for manufacturing multifunctional polymeric medical devices is restricted due to their tendency to degrade in the hot melt extrusion process. In this study, the potential of sub- and near-critical carbon dioxide (CO2) as a reversible plasticiser was explored by injecting it into a twin-screw hot melt extrusion process of Pellethane thermoplastic polyurethane to decrease its melt process temperature. Its morphological, throughput, thermal, rheological, and mechanical performances were also evaluated. The resultant extrudates were characterised using scanning electron microscopy, parallel plate rotational rheometer, differential scanning calorimetry, thermogravimetric analysis, and tensile testing. The process temperature decreased from 185 to 160 °C. The rheology indicated that the reduction in melt viscosity was from 690 Pa.s to 439 Pa.s (36%) and 414 Pa.s (40%) at 4.14 and 6.89 MPa, respectively. The tensile modulus in the elastomeric region is enhanced from 5.93 MPa, without CO2 to 7.71 MPa with CO2 at both 4.14 and 6.89 MPa. The results indicate that the employment of both sub- and near-critical CO2 as a processing aid is a viable addition to conventional hot melt extrusion and that they offer more opportunities for thermosensitive drugs to be more stable in the molten stream of Pellethane thermoplastic polyurethane.

A feasibility study to determine the use of baited pots in Greenland halibut (Reinhardtius hippoglossoides) fisheries, supported by the use of underwater video observations.

High incidental catches of Greenland shark (Somniosus microcephalus) in Nunavut's Greenland halibut (Reinhardtius hippoglossoides) fishery has led to studies on the feasibility of capturing Greenland halibut with baited pots. In this study, catch rates among six experimental pots are compared. In addition to this, underwater video observations of Greenland halibut interacting with two of these experimental pot types are quantified in order to help provide recommendations on future pot designs. Catch rates of Greenland halibut differed among pots with different entrance mesh types, and none of the pots produced substantial amounts of bycatch. Strings of pots were deployed within a narrow corridor between baited gillnets targeting Greenland halibut, which may have affected catch results. Video observations revealed Greenland halibut entangled by their teeth significantly more often in entrance funnels constructed with 50 mm than with 19 mm clear monofilament netting and the entrance rate was 45% higher with the 19 mm netting. Greenland halibut that successfully entered a pot repeatedly became entangled by their teeth in 58 mm netting used in the side and end panels and in a horizontal panel used to separate the pot into a lower and upper chamber. The majority (80%) of Greenland halibut were observed to approach a pot against the current. The downstream entrance was aligned with the current in 52% of the observed Greenland halibut approaches. Seventy percent of entry attempts and 67% of successful entries occurred when fish approached against the current and when the entrance was aligned with the current. These observations lead to recommendations that future studies consider developing a four entrance pot to ensure an entrance is always aligned with bottom currents. Based on these observations of entanglements, it is recommended to use 19 mm clear monofilament netting in the entrance funnel, 100 mm polyethylene netting in the exterior panels, and 19 mm polypropylene netting in the horizontal panel when targeting Greenland halibut. Three Greenland sharks were observed interacting with the pots in the video sets, but none were captured or damaged the pots during the potting experiments, providing validity to the use of pots to mitigate the capture of Greenland shark in Nunavut territorial waters.

The impact of pain on the pharmacokinetics of transdermal flunixin meglumine administered at the time of cautery dehorning in Holstein calves.

OBJECTIVE: To study the influence of pain on the pharmacokinetics and anti-inflammatory actions of transdermal flunixin administered at dehorning. STUDY DESIGN: Prospective, crossover, clinical study. ANIMALS: A total of 16 male Holstein calves, aged 6-8 weeks weighing 61.3 ± 6.6 kg. METHODS: Calves were randomly assigned to one of two treatments: transdermal flunixin and dehorning (PAIN) or transdermal flunixin and sham dehorning (NO PAIN). Flunixin meglumine (3.33 mg kg-1) was administered topically as a pour-on concurrently with hot iron dehorning or sham dehorning. The calves were subjected to the alternative treatment 14 days later. Blood samples were collected at predetermined time points up to 72 hours for measurement of plasma flunixin concentrations. Pharmacokinetics parameters were determined using noncompartmental analysis. Prostaglandin E2 (PGE2) concentration was determined using a commercial enzyme-linked immunosorbent assay. The 80% inhibition concentration (IC80) of PGE2 was determined using nonlinear regression. Pharmacokinetic data were statistically analyzed using paired t tests and Wilcoxon rank sums for nonparametric data. Flunixin and PGE2 concentrations were log transformed and analyzed using repeated measures. RESULTS: A total of 15 calves completed the study. Plasma half-life of flunixin was significantly longer in PAIN (10.09 hours) than NO PAIN (7.16 hours) (p = 0.0202). Bioavailability of transdermal flunixin was 30% and 37% in PAIN and NO PAIN, respectively (p = 0.097). Maximum plasma concentrations of flunixin were 0.95 and 1.16 µg mL-1 in PAIN and NO PAIN, respectively (p = 0.089). However, there was a treatment (PAIN versus NO PAIN) by time interaction (p = 0.0353). PGE2 concentrations were significantly lower in the PAIN treatment at 48 and 72 hours (p = 0.0092 and p = 0.0287, respectively). The IC80 of PGE2 by flunixin was similar in both treatments (p = 0.88). CONCLUSION AND CLINICAL RELEVANCE: Pain alters the pharmacokinetics and anti-inflammatory effects of transdermally administered flunixin.

Comparing catch efficiency of five models of pot for use in a Newfoundland and Labrador cod fishery.

Sustainability of commercial fisheries is best achieved when fishing gears are selective and have low impacts on bottom habitat. Pots (baited traps) are a fishing technology that typically has lower impacts than many other industrial gears. In this study we compared the efficiency of five models of pots (baited traps) designed to catch Atlantic cod (Gadus morhua) for use in Newfoundland and Labrador (NL)'s expanding cod fishery. We compared catch per unit effort (CPUE) and total lengths of cod across each pot type, as well as bycatch rates of each model. All pot types were successful at catching cod, but two models (the modified Newfoundland pot, and a four-entrance pot of our design) had highest CPUE. Specifically, we found that modifying Newfoundland pots increased their CPUE by 145% without a corresponding increase in bycatch. None of the pot types produced substantial amounts of bycatch. This study demonstrated that potting gear is an effective way to catch cod in NL, and that there is flexibility in which pot fishers can use, depending on the layout of their fishing vessel.

Effect of age on the pharmacokinetics and pharmacodynamics of flunixin meglumine following intravenous and transdermal administration to Holstein calves.

OBJECTIVE To determine the effect of age on the pharmacokinetics and pharmacodynamics of flunixin meglumine following IV and transdermal administration to calves. ANIMALS 8 healthy weaned Holstein bull calves. PROCEDURES At 2 months of age, all calves received an injectable solution of flunixin (2.2 mg/kg, IV); then, after a 10-day washout period, calves received a topical formulation of flunixin (3.33 mg/kg, transdermally). Blood samples were collected at predetermined times before and for 48 and 72 hours, respectively, after IV and transdermal administration. At 8 months of age, the experimental protocol was repeated except calves received flunixin by the transdermal route first. Plasma flunixin concentrations were determined by liquid chromatography-tandem mass spectroscopy. For each administration route, pharmacokinetic parameters were determined by noncompartmental methods and compared between the 2 ages. Plasma prostaglandin (PG) E2 concentration was determined with an ELISA. The effect of age on the percentage change in PGE2 concentration was assessed with repeated-measures analysis. The half maximal inhibitory concentration of flunixin on PGE2 concentration was determined by nonlinear regression. RESULTS Following IV administration, the mean half-life, area under the plasma concentration-time curve, and residence time were lower and the mean clearance was higher for calves at 8 months of age than at 2 months of age. Following transdermal administration, the mean maximum plasma drug concentration was lower and the mean absorption time and residence time were higher for calves at 8 months of age than at 2 months of age. The half maximal inhibitory concentration of flunixin on PGE2 concentration at 8 months of age was significantly higher than at 2 months of age. Age was not associated with the percentage change in PGE2 concentration following IV or transdermal flunixin administration. CONCLUSIONS AND CLINICAL RELEVANCE In calves, the clearance of flunixin at 2 months of age was slower than that at 8 months of age following IV administration. Flunixin administration to calves may require age-related adjustments to the dose and dosing interval and an extended withdrawal interval.

Variability in iodine in temperate seaweeds and iodine accumulation kinetics of Fucus vesiculosus and Laminaria digitata (Phaeophyceae, Ochrophyta).

The biogeochemistry of iodine in temperate coastal ecosystems is largely mediated by macroalgae, which act as a major biological sink and source of iodine. Their capacity to accumulate, retain and release iodine has been associated with abiotic and biotic stressors, but quantitative information is limited. We evaluated the seasonal iodine retention capacity of eleven macroalgal species belonging to different systematic groups, collected from two sites in Ireland. Iodine accumulation and retention were then further quantified in Fucus vesiculosus and Laminaria digitata in relation to I- concentrations in seawater and temperature. In general, iodine contents were ~101 -102  µmol · (g dw)-1 for Laminariales, 100 -101  µmol · (g dw)-1 for Fucales, 10-1 -100  µmol · (g dw)-1 for Rhodophyta, and 10-1  µmol · (g dw)-1 for Chlorophyta. Typically, algal iodine contents were above average in winter and below average in summer. Iodine accumulation in F. vesiculosus and L. digitata depended on I- availability and followed the Michaelis-Menten kinetic. The ratio of maximum accumulation rate to half accumulation coefficient (ρmax : Kt ) was 2.4 times higher for F. vesiculosus than for L. digitata, suggesting that F. vesiculosus was more efficient in iodine accumulation. Both species exhibited a temperature-dependent net loss of iodine, and only an exposure to sufficient external I- concentrations compensated for this loss. This study revealed that both environmental (e.g., I- in seawater, temperature) and organismal (e.g., the status of the iodine storage pool) variables determine retention and variability in iodine in temperate seaweeds.

Will you swim into my parlour? In situ observations of Atlantic cod (Gadus morhua) interactions with baited pots, with implications for gear design.

Pots (also known as traps) are baited fishing gears widely used in commercial fisheries, and are being considered as a tool for harvesting Atlantic cod (Gadus morhua) in Newfoundland and Labrador, Canada. Pots produce lower environmental impacts than many other fishing gears, but they will only be a viable fishing strategy if they are efficient and selective at catching their target species. To study the behaviour of cod in and around pots, and how those behaviours affect pot efficiency, we used long-duration underwater video cameras to assess two models of cod pot deployed in the nearshore waters of Fogo Island, NL. We examined the number of cod that approached the pot, the number and proportion that successfully completed entries into the pot openings, and the number that exited, and related these factors to the direction of water movement. We observed very few entry attempts relative to the number of approaches by cod, and only 22% of all entry attempts were successful. We observed that 50% of approaches, 70% of entry attempts, and 73% of successful entrances occurred against the current, and 25% of cod were able to exit the pot following capture. Based on our observations, we suggest that future cod pots should have a greater number of entrances, or a mechanism to ensure that entrances rotate in line with the current, in order to maximize their catch efficiency for cod.

Towards Low Energy Atrial Defibrillation.

A wireless powered implantable atrial defibrillator consisting of a battery driven hand-held radio frequency (RF) power transmitter (ex vivo) and a passive (battery free) implantable power receiver (in vivo) that enables measurement of the intracardiac impedance (ICI) during internal atrial defibrillation is reported. The architecture is designed to operate in two modes: Cardiac sense mode (power-up, measure the impedance of the cardiac substrate and communicate data to the ex vivo power transmitter) and cardiac shock mode (delivery of a synchronised very low tilt rectilinear electrical shock waveform). An initial prototype was implemented and tested. In low-power (sense) mode, >5 W was delivered across a 2.5 cm air-skin gap to facilitate measurement of the impedance of the cardiac substrate. In high-power (shock) mode, >180 W (delivered as a 12 ms monophasic very-low-tilt-rectilinear (M-VLTR) or as a 12 ms biphasic very-low-tilt-rectilinear (B-VLTR) chronosymmetric (6ms/6ms) amplitude asymmetric (negative phase at 50% magnitude) shock was reliably and repeatedly delivered across the same interface; with >47% DC-to-DC (direct current to direct current) power transfer efficiency at a switching frequency of 185 kHz achieved. In an initial trial of the RF architecture developed, 30 patients with AF were randomised to therapy with an RF generated M-VLTR or B-VLTR shock using a step-up voltage protocol (50-300 V). Mean energy for successful cardioversion was 8.51 J ± 3.16 J. Subsequent analysis revealed that all patients who cardioverted exhibited a significant decrease in ICI between the first and third shocks (5.00 Ω (SD(σ) = 1.62 Ω), p < 0.01) while spectral analysis across frequency also revealed a significant variation in the impedance-amplitude-spectrum-area (IAMSA) within the same patient group (|∆(IAMSAS1-IAMSAS3)[1 Hz - 20 kHz] = 20.82 Ω-Hz (SD(σ) = 10.77 Ω-Hz), p < 0.01); both trends being absent in all patients that failed to cardiovert. Efficient transcutaneous power transfer and sensing of ICI during cardioversion are evidenced as key to the advancement of low-energy atrial defibrillation.

"The Human Condition" as social ontology: Hannah Arendt on society, action and knowledge.

Hannah Arendt is widely regarded as a political theorist who sought to rescue politics from "society," and political theory from the social sciences. This conventional view has had the effect of distracting attention from many of Arendt's most important insights concerning the constitution of "society" and the significance of the social sciences. In this article, I argue that Hannah Arendt's distinctions between labor, work, and action, as these are discussed in "The Human Condition" and elsewhere, are best understood as a set of claims about the fundamental structures of human societies. Understanding Arendt in this way introduces interesting parallels between Arendt's work and both classical and contemporary sociology. From this I draw a number of conclusions concerning Arendt's conception of "society," and extend these insights into two contemporary debates within contemporary theoretical sociology: the need for a differentiated ontology of the social world, and the changing role that novel forms of knowledge play in contemporary society as major sources of social change and order.