On the Negative Disjunction Property

In the field of intermediate logics, the concept of the disjunction property (DP)  plays an important part. Lloyd Humberstone has drawn my attention to an analogious principle  called the Negative Disjunction Property ( NDP) which applies when the disjuncts involved are negated. The author investigates the NDP in the case of intermediate propositional logics. Key words: intermediate logic, disjunction property, negative disjunction property, Heyting algebra, Janko

On the Negative Disjunction Property

In the field of intermediate logics, the concept of the disjunction property (DP)  plays an important part. Lloyd Humberstone has drawn my attention to an analogious principle  called the Negative Disjunction Property ( NDP) which applies when the disjuncts involved are negated. The author investigates the NDP in the case of intermediate propositional logics. Key words: intermediate logic, disjunction property, negative disjunction property, Heyting algebra, Janko

Tolerance of Pseudomonas aeruginosa in in vitro biofilms to high level peracetic acid disinfection

Biofilm has been suggested as a cause of disinfection failures in flexible endoscopes where no lapses in the decontamination procedure can be identified. To test this theory, the activity of peracetic acid (PAA), one of the commonly used disinfectants in the reprocessing of flexible endoscopes, was evaluated against both planktonic and sessile communities of Pseudomonas aeruginosa. To investigate the ability of P. aeruginosa biofilm to survive high level PAA disinfection. The susceptibility of planktonic cells of P. aeruginosa and biofilms 24, 48, 96 and 192 h old to PAA was evaluated by estimating their viability using resazurin viability and plate count methods. The biomass of the P. aeruginosa biofilms was also quantified using crystal violet assay. Planktonic cells of P. aeruginosa were treated with 5 - 30 ppm concentration of PAA in the presence of 3.0 g/L of Bovine serum albumin (BSA) for 5 min. Biofilms of P. aeruginosa were also treated with various PAA concentrations (100 - 3000 ppm) for 5 min. Planktonic cells of P. aeruginosa were eradicated by 20 ppm of PAA, whereas biofilms showed an age dependent tolerance to PAA, and 96 h old biofilm was only eradicated at PAA concentration of 2500 ppm. 96 h old P. aeruginosa biofilm survives 5 min treatment with 2000 ppm of PAA, which is the working concentration used in some endoscope washer disinfectors. This implies that disinfection failure of flexible endoscopes could occur when biofilms are allowed to build up in the lumens of endoscopes

Implementation of the Activate injury prevention exercise programme in English schoolboy rugby union

Objectives: The implementation of the Activate injury prevention exercise programme has not been assessed in an applied context. This study aimed to (1) describe the knowledge and perceptions of school rugby coaches and players towards injury risk, prevention and Activate and (2) evaluate Activate implementation in schoolboy rugby using the reach, effectiveness, adoption, implementation and maintenance framework. Methods: Bespoke electronic surveys were administered to coaches (including support staff) and players at participating English schools (2018–2020). Most questions and statements were answered using a 7-point Likert scale. At baseline, participants detailed their Activate awareness and perceptions of injury risk and prevention in schoolboy rugby. At postseason, participants reported Activate use throughout the study and their perceptions towards the programme. Results: At baseline, significant differences existed between coaches (n=106) and players (n=571) in Activate awareness (75% and 13% respectively; χ2=173.5, p<0.001). Coaches perceived rugby had a significantly greater injury risk than players, while holding more positive perceptions towards injury prevention. At postseason, coaches reported greater Activate adoption compared with players (76% and 18% respectively; χ2=41.8, p<0.001); 45% of players were unaware if they used the programme. Median session adherence was twice weekly, with a median duration of 10–15 min. This suggests Activate was not implemented as intended, with recommendations of three 20 min sessions per week. Both groups identified common barriers to implementation, such as lack of time and inclusion of a ball. Conclusion: Coaches are instrumental in the decision to implement Activate. Targeting behavioural change in these individuals is likely to have the greatest impact on intervention uptake

Rare Earth Element Partition Coefficients from Enstatite/Melt Synthesis Experiments

Enstatite (En(80)Fs(19)Wo(01)) was synthesized from a hypersthene normative basaltic melt doped at the same time with La, Ce, Nd, Sm, Eu, Dy, Er, Yb and Lu. The rare earth element concentrations were measured in both the basaltic glass and the enstatite. Rare earth element concentrations in the glass were determined by electron microprobe analysis with uncertainties less than two percent relative. Rare earth element concentrations in enstatite were determined by secondary ion mass spectrometry with uncertainties less than five percent relative. The resulting rare earth element partition signature for enstatite is similar to previous calculated and composite low-Ca pigeonite signatures, but is better defined and differs in several details. The partition coefficients are consistent with crystal structural constraints

Employing standardised methods to compare injury risk across seven youth team sports

Injury surveillance systems seek to describe injury risk for a given sport, in order to inform preventative strategies. This often leads to comparisons between studies, although these inferences may be inappropriate, considering the range of methods adopted. This study aimed to describe the injury epidemiology of seven youth sports, enabling valid comparisons of injury risk. Consistent methods were employed across seven sports [male American football, basketball, soccer, rugby league, rugby union; female soccer and rugby union] at a high school in England. A 24-hour time-loss injury definition was adopted. Descriptive statistics and injury incidence (/1000 match-hours) are reported. In total, 322 injuries were sustained by 240 athletes (mean age=17.7±1.0) in 10 273 player-match hours. American football had a significantly greater injury incidence (86/1000 h; 95% CI 61–120) than all sports except female rugby union (54/1000 h; 95% CI 37–76). Concussion was the most common injury (incidence range 0.0–26.7/1000 h), while 59% of injuries occurred via player contact. This study employed standardized data collection methods, allowing valid and reliable comparisons of injury risk between youth sports. This is the first known study to provide epidemiological data for female rugby union, male basketball and American football in an English youth population, enabling the development of preventative strategies

Activity-based protein profiling of the hepatitis C virus replication in Huh-7 hepatoma cells using a non-directed active site probe

<p>Abstract</p> <p>Background</p> <p>Hepatitis C virus (HCV) poses a growing threat to global health as it often leads to serious liver diseases and is one of the primary causes for liver transplantation. Currently, no vaccines are available to prevent HCV infection and clinical treatments have limited success. Since HCV has a small proteome, it relies on many host cell proteins to complete its life cycle. In this study, we used a non-directed phenyl sulfonate ester probe (PS4≡) to selectively target a broad range of enzyme families that show differential activity during HCV replication in Huh-7 cells.</p> <p>Results</p> <p>The PS4≡ probe successfully targeted 19 active proteins in nine distinct protein families, some that were predominantly labeled <it>in situ </it>compared to the <it>in vitro </it>labeled cell homogenate. Nine proteins revealed altered activity levels during HCV replication. Some candidates identified, such as heat shock 70 kDa protein 8 (or HSP70 cognate), have been shown to influence viral release and abundance of cellular lipid droplets. Other differentially active PS4≡ targets, such as electron transfer flavoprotein alpha, protein disulfide isomerase A5, and nuclear distribution gene C homolog, constitute novel proteins that potentially mediate HCV propagation.</p> <p>Conclusions</p> <p>These findings demonstrate the practicality and versatility of non-directed activity-based protein profiling (ABPP) to complement directed methods and accelerate the discovery of altered protein activities associated with pathological states such as HCV replication. Collectively, these results highlight the ability of <it>in situ </it>ABPP approaches to facilitate the identification of enzymes that are either predominantly or exclusively labeled in living cells. Several of these differentially active enzymes represent possible HCV-host interactions that could be targeted for diagnostic or therapeutic purposes.</p