2,833 research outputs found
Synthesis and application of hypercrosslinked polymers with weak cation-exchange character for the selective extraction of basic pharmaceuticals from complex environmental water samples
The synthesis of high specific surface area sorbents (HXLPP-WCX) in the form of hypercrosslinked polymer microspheres with narrow particle size distributions, average particle diameters around 6 µm, and weak cation exchange (WCX) character, is described. The WCX character arises from carboxylic acid moieties in the polymers, derived from the comonomer methacrylic acid. A novel HXLPP-WCX sorbent with an attractive set of chemical and physical properties was then used in an off-line solid-phase extraction (SPE) protocol for the selective extraction of a group of basic compounds from complex environmental samples, a priority being the clean separation of the basic compounds of interest from acidic compounds and interferences. The separation power of the new sorbent for basic pharmaceuticals was compared to two commercially available, mixed-mode sorbents, namely Oasis WCX and Strata X-CW. Under identical experimental conditions, HXLPP-WCX was found to deliver both higher capacity and better selectivity in SPE than either of the two commercially available materials. In an optimised SPE protocol, the HXLPP-WCX sorbent gave rise to quantitative and selective extractions of low µg l-1 levels of basic pharmaceuticals present in 500 ml of river water and 250 ml of effluent waste water
Hydrophilic hypercrosslinked polymeric sorbents for the solid-phase extraction of polar contaminants from water
Three new hypercrosslinked polymers with hydrophilic character arising from hydroxyl moieties in their skeletons have been prepared in microsphere format and applied to the off-line solid-phase extraction (SPE) of polar compounds from water samples. For sample volumes of 1000 ml, the recoveries of various polar pesticides, such as oxamyl, methomyl, selected phenolic compounds, as well as some pharmaceuticals, were close to 90%. The HXLPP-polar polymer with the best performance characteristics was applied to real samples. Its performance was also compared to commercially available sorbents, such as LiChrolut EN (hydrophobic, hypercrosslinked), Oasis HLB (hydrophilic, macroporous) and Isolute ENV+ (hydrophilic, hypercrosslinked); the new sorbent out-performed the commercially available sorbents. The polymer was applied successfully in off-line SPE of river water samples followed by liquid chromatography and ultraviolet detection, providing a good linear range and detection limits of 0.2 μg l-1 for the majority of the compounds, with the exception of oxamyl, methomyl, guaiacol and salicylic acid where the detection limit was 0.5 μg l-1
Natural convection in a shallow cavity with differentially heated end walls. Part 2. Numerical solutions
Numerical solutions of the full Navier-Stokes equations are obtained for the problem of natural convection in closed cavities of small aspect ratio with differentially
heated end walls. These solutions cover the parameter range
Pr = 6.983, 10 ≤ Gr ≤ 2x10^4 and 0.05 ≤ A ≤ 1. A comparison with the asymptotic theory of part 1 shows excellent agreement between the analytical and numerical solutions provided that A ≾ 0.1 and Gr^2A^3Pr^2 ≾ l0^5. In addition,
the numerical solutions demonstrate the transition between the shallow-cavity limit of part 1 and the boundary-layer limit; A fixed, Gr → ∞
General practice ethnicity data: evaluation of a tool
INTRODUCTION: There is evidence that the collection of ethnicity data in New Zealand primary care is variable and that data recording in practices does not always align with the procedures outlined in the Ethnicity Data Protocols for the Health and Disability Sector. In 2010, The Ministry of Health funded the development of a tool to audit the collection of ethnicity data in primary care. The aim of this study was to pilot the Ethnicity Data Audit Tool (EAT) in general practice. The goal was to evaluate the tool and identify recommendations for its improvement.
METHODS: Eight general practices in the Waitemata District Health Board region participated in the EAT pilot. Feedback about the pilot process was gathered by questionnaires and interviews, to gain an understanding of practices’ experiences in using the tool. Questionnaire and interview data were analysed using a simple analytical framework and a general inductive method.
FINDINGS: General practice receptionists, practice managers and general practitioners participated in the pilot. Participants found the pilot process challenging but enlightening. The majority felt that the EAT was a useful quality improvement tool for handling patient ethnicity data. Larger practices were the most positive about the tool.
CONCLUSION: The findings suggest that, with minor improvements to the toolkit, the EAT has the potential to lead to significant improvements in the quality of ethnicity data collection and recording in New Zealand general practices. Other system-level factors also need to be addressed
The influence of different length between match microcycles on neuromuscular, hormonal and perceptual responses in professional rugby league players
Optimal recovery between matches is critically important in team sports. Indeed, altered neuromuscular performance, hormone levels and increased fatigue can manifest in under recovered team sport athletes. However, the recovery patterns in these variables in the days following professional rugby league matches is unknown. The purpose of this study was to examine the influence of different between-match training periods on neuromuscular, hormonal and perceptual measures in professional rugby league players. Following familiarization, 12 professional rugby league players from the same team were assessed for changes in countermovement jump (CMJ) (force, power, flight time), perceptual responses (fatigue, well being and muscle soreness) and salivary hormone (testosterone (T) and cortisol (C)) levels during 5, 7 and 9 day periods between matches. Measures were taken 4h prior to the initial match, and then 1, 2, 4, 6*, 7*, 8* and 9* days following (*depending on group). All training was prescribed by the coaches and monitored using the session-RPE method. Lower daily training load was completed on the 5-day compared with the 7 and 9-day conditions (p\u3c0.05). Some CMJ variables (flight time and flight time:contraction time), perception of fatigue, well-being and muscle soreness were reduced in the 2 days following the match in each condition (p\u3c0.05). All CMJ variables returned to near baseline values following 4 days in each condition. Both CMJ maximum and relative power were lower in the 7 day condition when compared with the 9 day condition (p\u3c0.05). Fatigue levels were reduced at 48 h in the 7 and 9-day groups (p\u3c0.05) but had returned to baseline in the 5-day group. All perceptual measures returned to baseline levels prior to the following match in each condition and followed changes in training load. Salivary T and C did not change in response to the match. These results show that neuromuscular performance and perception of fatigue are reduced for at least 48 h following a rugby league match but these can be fully recovered within 4 days. CMJ variables involving flight time appear to be best for assessing acute fatigue caused by a match, and variables involving power may be useful in assessing accumulated fatigue. The perceptual measures were sensitive to both acute fatigue and accumulated fatigue. The salivary hormone analyses were of limited value for assessing recovery. These findings show that with correct training, it is possible to recover neuromuscular, perceptual and endocrine measures within 4 days after a rugby league match
Continuous macroscopic limit of a discrete stochastic model for interaction of living cells
In the development of multiscale biological models it is crucial to establish
a connection between discrete microscopic or mesoscopic stochastic models and
macroscopic continuous descriptions based on cellular density. In this paper a
continuous limit of a two-dimensional Cellular Potts Model (CPM) with excluded
volume is derived, describing cells moving in a medium and reacting to each
other through both direct contact and long range chemotaxis. The continuous
macroscopic model is obtained as a Fokker-Planck equation describing evolution
of the cell probability density function. All coefficients of the general
macroscopic model are derived from parameters of the CPM and a very good
agreement is demonstrated between CPM Monte Carlo simulations and numerical
solution of the macroscopic model. It is also shown that in the absence of
contact cell-cell interactions, the obtained model reduces to the classical
macroscopic Keller-Segel model. General multiscale approach is demonstrated by
simulating spongy bone formation from loosely packed mesenchyme via the
intramembranous route suggesting that self-organizing physical mechanisms can
account for this developmental process.Comment: 4 pages, 3 figure
Evolution of a fluorinated green fluorescent protein
The fluorescence of bacterial cells expressing a variant (GFPm) of the green fluorescent protein (GFP) was reduced to background levels by global replacement of the leucine residues of GFPm by 5,5,5-trifluoroleucine. Eleven rounds of random mutagenesis and screening via fluorescence-activated cell sorting yielded a GFP mutant containing 20 amino acid substitutions. The mutant protein in fluorinated form showed improved folding efficiency both in vivo and in vitro, and the median fluorescence of cells expressing the fluorinated protein was improved {approx}650-fold in comparison to that of cells expressing fluorinated GFPm. The success of this approach demonstrates the feasibility of engineering functional proteins containing many copies of abiological amino acid constituents
The role of the group in mindfulness-based interventions.
Mindfulness-based interventions (MBIs) such as Mindfulness-based Stress Reduction and Mindfulness-based Cognitive Therapy utilise a group format. Experts in the field of mindfulness endorse the group as beneficial to participants and professional practice literature promotes the need for mindfulness teachers to develop competence in group skills. However, the role of the group in MBIs has been largely overlooked in empirical research to date and the utility of existing group theory in this area is unconvincing. The current study presents a grounded-theory of the role of the group in MBIs. The theory was developed from semi-structured interviews conducted with mindfulness students, teachers and trainers (N=12) exploring their experiences and views related to the MBI group format. Through analysis, three higher-order categories emerged from the data describing five stages of group experiences, four group-based tasks the teacher attended to from a position of ‘embodiment’, and the impact of the MBI group. Findings were situated within existing group theory, facilitating differentiation between generic and MBI specific group factors. The sense of connection developed through non-verbal group meditation, the multi-layered experience of normalization, and the grounding of the teacher’s group-based responses in the embodiment of mindfulness, emerged as unique MBI group factors. The implications for clinical practice, research and theory are discussed
- …
