A longitudinal examination of the relationship between cannabis use and cognitive function in mid-life adults

Background: The relationship between cannabis use and cognitive function in mid-life has rarely been examined despite verbal learning deficits in young adults. Method: A longitudinal cohort study of 1,897 Australians recruited at 40–46 years of age and followed up 4 years (94%) and 8 years (87%) later. Random effects regression was used to assess within- and between-person associations between cannabis use and cognitive function across waves of data, and examine whether age-related changes in cognitive performance were modified by cannabis use. The first list of the California Verbal Learning Test (immediate and delayed recall), Symbol Digit Modality Test, Digit Backwards, simple and choice reaction time tasks, were administered at each wave. The Spot-the-Word test was used to assess premorbid verbal ability. Self-reported cannabis use in the past year (no use, < weekly use, ≥ weekly use) was assessed at each wave. Findings: Participants who used cannabis ≥ weekly had worse immediate recall (b = −0.68, p = 0.014) and showed a trend toward worse delayed recall (b = −0.55, p = 0.062) compared to non-users after adjusting for correlates of cannabis use and premorbid verbal ability. These effects were due to between-person differences. There were no significant within-person associations between cannabis use and recall, nor was there evidence of greater cognitive decline in cannabis users with age. Conclusions: Mid-life cannabis users had poorer verbal recall than non-users, but this was not related to their current level of cannabis use, and cannabis use was not associated with accelerated cognitive decline

Enzyme mass transfer coefficient in aqueous two-phase systems: modified spray extraction columns

The fractional dispersed phase hold-up and mass transfer coefficients were measured in modified spray columns of 50 mm i.d. using an aqueous two phase system of polyethylene glycol (PEG 4000)-sodium sulphate-buffer. The mass transfer coefficients were measured for amyloglucosidase and β-galactosidase. Both co-current and countercurrent modes of operation were investigated. The dispersed phase hold-up (ε<SUB>D</SUB>) and the dispersed phase and the continuous phase mass transfer coefficients (k<SUB>D</SUB>a, k<SUB>C</SUB>a) increased with increasing dispersed phase velocity. An increase in the phase concentration of sodium sulphate and PEG was found to reduce ε<SUB>D</SUB>, k<SUB>D</SUB>a, and k<SUB>C</SUB>a. The performance of the modified spray column is compared with the conventional spray column. The modifications resulted into about a ten-fold enhancement in the throughput and about a five-fold reduction in the value of the height of a transfer unit (HTU ). It has been shown that the value of HTU of the order of 1 m can be obtained. Empirical correlations for ε<SUB>D </SUB>and k<SUB>D</SUB>a, k<SUB>C</SUB>a have been proposed

The Surveillance After Extremity Tumor Surgery (SAFETY) trial: protocol for a pilot study to determine the feasibility of a multi-centre randomised controlled trial

Introduction Following the treatment of patients with soft tissue sarcomas (STS) that are not metastatic at presentation, the high risk for local and systemic disease recurrence necessitates post-treatment surveillance. Systemic recurrence is most often detected in the lungs. The most appropriate surveillance frequency and modality remain unknown and, as such, clinical practice is highly varied. We plan to assess the feasibility of conducting a multi-centre randomised controlled trial (RCT) that will evaluate the effect on overall 5-year survival of two different surveillance frequencies and imaging modalities in patients with STS who undergo surgical excision with curative intent.Methods and analysis The Surveillance After Extremity Tumor Surgery trial will be a multi-centre 2x2 factorial RCT. Patients with non-metastatic primary Grade II or III STS treated with excision will be allocated to one of four treatment arms(1): chest radiograph (CXR) every 3 months for 2 years(2); CXR every 6 months for 2 years(3); chest CT every 3 months for 2 years or(4) chest CT every 6 months for 2years. The primary outcome of the pilot study is the feasibility of a definitive RCT based on a combination of feasibility endpoints. Secondary outcomes for the pilot study include the primary outcome of the definitive trial (overall survival), patient-reported outcomes on anxiety, satisfaction and quality of life, local recurrence-free survival, metastasis-free survival, treatment-related complications and net healthcare costs related to surveillance.Ethics and dissemination This trial received provisional ethics approval from the McMaster/Hamilton Health Sciences Research Ethics Board on 7 August 2019 (Project number 7562). Final ethics approval will be obtained prior to commencing patient recruitment. Once feasibility has been established and the definitive protocol is finalised, the study will transition to the definitive study