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DNA origami purification is critical in emerging applications of functionalized DNA nanostructures from basic fundamental biophysics, nanorobots to therapeutics. Advances in DNA origami purification have led to the establishment of rate-zonal centrifugation (RZC) as a scalable, high-yield, and contamination-free approach to purifying DNA origami nanostructures. In RZC purification, a linear density gradient is created using viscous agents, such as glycerol and sucrose, to separate molecules based on their mass and shape during high-rpm centrifugation. However, current methods for creating density gradients are typically time-consuming because of their reliance on slow passive diffusion. Here, we built a LEGO gradient mixer to rapidly create a quasi-continuous density gradient with minimal layering of concentrations using simple rotational motion. We found that rotating two layers of different concentrations at an angle can reduce the diffusion time from a few hours to mere minutes. The instrument needed to perform the movement can be constructed from low-cost components, such as Arduino and LEGO Mindstorms pieces, and has comparable efficacy to commercial gradient mixers currently available. Our results demonstrate that the creation of a linear density gradient can be achieved with minimal labor, time, and cost with this machine. With the recent advances in DNA origami production, we anticipate our findings to further improve the viability of scaling up DNA origami purification in grams quantities. Our simple process enables automated large-scale purification of functionalized DNA origami more feasible in resource-constrained settings.

Background. The pharmacokinetics of bictegravir (BIC) and its association with the decay of human immunodeficiency virus (HIV)-1 RNA in genital fluids and the rectum have not yet been addressed. Methods. We conducted a prospective, multicenter study of antiretroviral-naive people living with HIV-1 and initiating BIC/emtricitabine (FTC)/tenofovir alafenamide (TAF). HIV-1 RNA was measured (limit of quantification, 40 copies/mL) in blood plasma (BP), seminal plasma (SP), rectal fluid (RF), and cervicovaginal fluid (CVF) at baseline; Days 3, 7, 14, and 28; and Weeks 12 and 24. Total and protein-unbound BIC concentrations at 24 hours postdose (C 24h) were quantified in BP, SP, CVF and rectal tissue (RT) on Day 28 and Week 12 using a validated liquid chromatography-tandem mass spectrometry assay. Results. The study population comprised 15 males and 8 females. In SP, RF, and CVF, the baseline HIV-1 RNA was >40 copies/mL in 12/15, 13/15, and 4/8 individuals, respectively, with medians of 3.54 (2.41-3.79), 4.19 (2.98-4.70), and 2.56 (1.61-3.56) log 10 copies/mL, respectively. The initial decay slope was significantly lower in SP than in RF and BP. The time to undetectable HIV-1 RNA was significantly shorter in SP and RF than in BP. All women achieved undetectable HIV-1 RNA in CVF at Day 14. The median total BIC concentrations in SP, RT, and CVF were 65.5 (20.1-923) ng/mL, 74.1 (6.0-478.5) ng/g, and 61.6 (14.4-1760.2) ng/mL, respectively, representing 2.7%, 2.6%, and 2.8% of the BP concentration, respectively, while the protein-unbound fractions were 51.1%, 44.6%, and 42.6%, respectively. Conclusions. BIC/FTC/TAF led to rapid decay of HIV-1 RNA in genital and rectal fluids. Protein-unbound BIC concentrations in SP, RT, and CVF highly exceeded the half-maximal effective concentration (EC50) value (1.1 ng/mL).

This document is an English-language abstract (approximately 1,500 words) of a study by the Australian Council for Educational Research (Commonwealth Advisory Committee on Advanced Education) responding to the stated purposes of the project to study the explicit and implicit objectives of the courses, the nature and extent of their content, how and by whom they are determined, how they are subdivided into years, how instruction influences learning, procedures used in evaluation of student performance, and weak and strong learning conditions. It was found that many colleges had not clearly defined their role in higher education, with a general lack of clearly defined objectives on the department level. A critical examination of course class hours should be made to reduce them, particularly in engineering and business administration. Prior to this study, no information was available on college students and their characteristics. Many instructors had never taken a course in teacher training. There is a trend towards continuous progress assessment, preferred by both students and instructors over the end of year examination only. Consideration of part-time students showed that in many cases courses were not geared to their special needs. Volumes I and II contain the report and the appendices, and are obtainable from the Australian Council for Educational Research for Aus. $5.00, plus .50 postage. Volume III, containing additional student data, is not for sale; applications for this volume should be made to Director, Australian Council for Educational Research. (Author/GDB)

This study describes the characteristics of Victorian college engineering students. Ninety percent of the second-year full-time engineering students filled out a questionnaire and provided information on: country of birth, age, sex and marital status, type of secondary school attended, subjects passed at leaving and matriculation level, scholarships, father's occupation, parents' educational level, and sibling tertiary education experience. By a series of cross-tabulations the students' replies were related to: college attended, location of college attended, field of engineering studies, and performance at annual examinations. The chi-squared test was applied to determine the significance of any differences found. The better performing students were found to be: Australian born, younger than average, former technical school students, and sons of tradesmen or manual workers with only a primary level education. Students' replies to a second questionnaire with data on their study habits and other related questions were cross-tabulated with subsequent performance at the annual examination. The study also examines the concept of advanced education and discusses a number of the implications of the material presented. (Author/AF)

OBJECTIVES: This study sought to investigate the role of secretory phospholipase A2 (sPLA2)-IIA in cardiovascular disease. BACKGROUND: Higher circulating levels of sPLA2-IIA mass or sPLA2 enzyme activity have been associated with increased risk of cardiovascular events. However, it is not clear if this association is causal. A recent phase III clinical trial of an sPLA2 inhibitor (varespladib) was stopped prematurely for lack of efficacy. METHODS: We conducted a Mendelian randomization meta-analysis of 19 general population studies (8,021 incident, 7,513 prevalent major vascular events [MVE] in 74,683 individuals) and 10 acute coronary syndrome (ACS) cohorts (2,520 recurrent MVE in 18,355 individuals) using rs11573156, a variant in PLA2G2A encoding the sPLA2-IIA isoenzyme, as an instrumental variable. RESULTS: PLA2G2A rs11573156 C allele associated with lower circulating sPLA2-IIA mass (38% to 44%) and sPLA2 enzyme activity (3% to 23%) per C allele. The odds ratio (OR) for MVE per rs11573156 C allele was 1.02 (95% confidence interval [CI]: 0.98 to 1.06) in general populations and 0.96 (95% CI: 0.90 to 1.03) in ACS cohorts. In the general population studies, the OR derived from the genetic instrumental variable analysis for MVE for a 1-log unit lower sPLA2-IIA mass was 1.04 (95% CI: 0.96 to 1.13), and differed from the non-genetic observational estimate (OR: 0.69; 95% CI: 0.61 to 0.79). In the ACS cohorts, both the genetic instrumental variable and observational ORs showed a null association with MVE. Instrumental variable analysis failed to show associations between sPLA2 enzyme activity and MVE. CONCLUSIONS: Reducing sPLA2-IIA mass is unlikely to be a useful therapeutic goal for preventing cardiovascular events.