Determinants of CRISPR Cas12a nuclease activation by DNA and RNA targets.

The RNA-guided CRISPR-associated (Cas) enzyme Cas12a cleaves specific double-stranded (ds-) or single-stranded (ss-) DNA targets (in cis), unleashing non-specific ssDNA cleavage (in trans). Though this trans-activity is widely coopted for diagnostics, little is known about target determinants promoting optimal enzyme performance. Using quantitative kinetics, we show formation of activated nuclease proceeds via two steps whereby rapid binding of Cas12a ribonucleoprotein to target is followed by a slower allosteric transition.

Simple photoplethysmography pulse encoding technique for communicating the detection of peripheral arterial disease-a proof of concept study.

Objective: To assess the feasibility of novel photoplethysmography (PPG) Pulse Sounder/Pulse Visualizer communication techniques for alerting the presence (or absence) of peripheral arterial disease (PAD).

Approach: Proof of concept evaluation using our previously published multi-site PPG pulse data set (110 participants included; age  >  40 years; 44% PAD by ankle brachial pressure index (ABPI)). Two main pulse encoding rules using the risetime as an example feature to mark each heartbeat in a 6 s analysis study window: if risetime at both great toes  ⩽time threshold ('no PAD' state) then heartbeat marked with a single 5 kHz audio tone; if risetime from either great toe  >  threshold ('PAD') then heartbeat marked with a distinct train of 5 kHz audio tones.

Evaluating the repeatability and set-up sensitivity of a large field of view distortion phantom and software for magnetic resonance-only radiotherapy.

Background And Purpose: Magnetic Resonance (MR)-only radiotherapy requires geometrically accurate MR images over the full scanner Field of View (FoV). This study aimed to investigate the repeatability of distortion measurements made using a commercial large FoV phantom and analysis software and the sensitivity of these measurements to small set-up errors.

Materials And Methods: Geometric distortion was measured using a commercial phantom and software with 2D and 3D acquisition sequences on three different MR scanners.

Oxopyrido[2,3-d]pyrimidines as Covalent L858R/T790M Mutant Selective Epidermal Growth Factor Receptor (EGFR) Inhibitors.

In nonsmall cell lung cancer (NSCLC), the threonine(790)-methionine(790) (T790M) point mutation of EGFR kinase is one of the leading causes of acquired resistance to the first generation tyrosine kinase inhibitors (TKIs), such as gefitinib and erlotinib. Herein, we describe the optimization of a series of 7-oxopyrido[2,3-d]pyrimidinyl-derived irreversible inhibitors of EGFR kinase. This led to the discovery of compound 24 which potently inhibits gefitinib-resistant EGFR(L858R,T790M) with 100-fold selectivity over wild-type EGFR.

Effective multiple oral administration of reverse genetics engineered infectious bursal disease virus in mice in the presence of neutralizing antibodies.

Background: Despite spectacular successes in hepatitis B and C therapies, severe hepatic impairment is still a major treatment problem. The clinically tested infectious bursal disease virus (IBDV) superinfection therapy promises an innovative, interferon-free solution to this great unmet need, provided that a consistent manufacturing process preventing mutations or reversions to virulent strains is obtained.

Methods: To address safety concerns, a tissue culture adapted IBDV vaccine strain V903/78 was cloned into cDNA plasmids ensuring reproducible production of a reverse engineered virus R903/78.