Principles of CRISPR-Cas13 mismatch intolerance enable selective silencing of point-mutated oncogenic RNA with single-base precision.

Single-nucleotide variants (SNVs) are extremely prevalent in human cancers, although most of these remain clinically unactionable. The programmable RNA nuclease CRISPR-Cas13 has been deployed to specifically target oncogenic RNAs. However, silencing oncogenic SNVs with single-base precision remains extremely challenging due to the intrinsic mismatch tolerance of Cas13.

Measurement of neutron yield for a medical linear accelerator below 10 MV.

Background: The recent trend toward 10 MV for volumetric radiotherapy treatment such as volumetric modulated arc therapy (VMAT), stereotactic radiosurgery (SRS), and stereotactic ablative body radiotherapy (SABR) introduces photoneutron production, with implications for non-therapeutic patient dose and additional shielding requirements for treatment room design. The sharply nonlinear drop-off in photoneutron production below 10 MV to negligible at 6 MV has scarcely been characterized quantitatively, yet can elucidate important practical insights.

Purpose: To measure photoneutron yields in a medical linac at 8 MV, which may strike a reasonable balance between usefully increased beam penetration and dose rate as compared to 6 MV while reducing photoneutron production which is present at 10 MV.

Automated conversion of Millennium-120 VMAT plans to HDMLC geometry: Software development and treatment of first patients.

Purpose: To provide plan backup resiliency for patients treated on a solitary high definition multileaf collimator (HDMLC) linac by developing a fully integrated Eclipse script, which converts patient plans initially optimized on Millennium-120 (M120) MLC to dosimetrically equivalent leaf motions for delivery on HDMLC. In the event of HDMLC machine downtime, affected patients can be transferred to Millennium-120 units, and their backup plan delivered without delay.

Methods: Write-enabled Eclipse scripting is leveraged to generate HDMLC treatment fields with control points parameterized to mimic apertures of an existing Millennium-120 VMAT plan.

Feasibility of streamline upwind Petrov-Galerkin angular stabilization of the linear Boltzmann transport equation with magnetic fields.

To accurately model dose in a magnetic field, the Lorentz force must be included in the traditional linear Boltzmann transport equation (LBTE). Both angular and spatial stabilization are required to deterministically solve this equation. In this work, a streamline upwind Petrov-Galerkin (SUPG) method is applied to achieve angular stabilization of the LBTE with magnetic fields.

Pegylated glucose gold nanoparticles for improved in-vivo bio-distribution and enhanced radiotherapy on cervical cancer.

Pharmacokinetics and bio-distribution are crucial factors affecting the performance of an intravenous drug. In this study, we explore the combined use of glucose and polyethylene glycol (PEG) ligands to further improve gold nanoparticle (GNP) pharmacokinetics and bio-distribution, with the aim of using the drug for in-vivo radiotherapy. The inclusion of PEG was found to significantly prolong the half-life period, where PEG-Glu-GNPs achieved 6.

Evaluating a Canadian regional air quality model using ground-based observations in north-eastern Canada and United States.

The simulated concentrations from a numerical 3-dimensional regional air quality model (MC2AQ) are compared to those of ground-based observations in north-eastern Canada and the United States. The model has oxidant chemistry for both inorganic and organic species and deposition routines driven online by a mesoscale compressible community meteorological model (MC2). A standard emission inventory of anthropogenic, natural and biogenic sources for the year 1990 for 21 atmospheric trace species was used in the simulation.