Technical note: TERMA scaling as an effective heterogeneity correction model for convolution-based external-beam photon dose calculations.

Background: In highly heterogeneous medium, such as one with lung tissue or air cavities, the dose in the low-density region or after it, as calculated by the conventional methods based on convolution with an energy-spreading kernel, is usually overestimated in comparison with measurements or more accurate predictions.

Purpose: To correct the overestimation, we propose a method of scaling the total energy released per mass (TERMA).

Methods: The scaling depends on both the density distribution and the effective beam size in the lateral direction.

Monte Carlo modeling of Halcyon and Ethos radiotherapy beam using CAD geometry: validation and IAEA-compliant phase space.

A Monte Carlo (MC) model of a Halcyon and Ethos (Varian Medical Systems, a Siemens Healthineers Company) radiotherapy beam was validated and field-independent phase space (PHSP) files were recorded above the dual-layer multileaf collimators (MLC).The treatment head geometry was modeled according to engineering drawings and the dual-layer MLC was imported from CAD (computer-aided design) files. The information for the incident electron beam was achieved from an iterative electromagnetic solver.

Russian nursing students' knowledge level and attitudes in the context of human immunodeficiency virus (HIV) - a descriptive study.

Background: The purpose of this study was to describe the knowledge of Russian nursing students regarding HIV and Acquired Immuno-Deficiency Syndrome (AIDS), and their attitudes towards caring for people/patients living with HIV or AIDS (PLWHA - People Living With HIV/AIDS) and their possible homophobic attitudes. The HIV epidemic in Russia is substantial and increasing rapidly. Hence this study provides important new information regarding this phenomenon.

Fibrinolytic and coagulative activities of Yersinia pestis.

The outer membrane protease Pla belongs to the omptin protease family spread by horizontal gene transfer into Gram-negative bacteria that infect animals or plants. Pla has adapted to support the life style of the plague bacterium Yersinia pestis. Pla has a β-barrel fold with 10 membrane-spanning β strands and five surface loops, and the barrel surface contains bound lipopolysaccharide (LPS) that is critical for the conformation and the activity of Pla.

Human single-chain urokinase is activated by the omptins PgtE of Salmonella enterica and Pla of Yersinia pestis despite mutations of active site residues.

Fibrinolysis is important in cell migration and tightly regulated by specific inhibitors and activators; of the latter, urokinase (uPA) associates with enhancement of cell migration. Active uPA is formed through cleavage of the single-chain uPA (scuPA). The Salmonella enterica strain 14028R cleaved human scuPA at the peptide bond Lys158-Ile159, the site cleaved also by the physiological activator human plasmin.