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The discussion of bullying highlights the problem of witnesses not intervening to help a victim. This is a common occurrence, as the following well-publicized event demonstrates. In 1964, in Queens, New York, a 19-year-old woman named Kitty Genovese was attacked by a person with a knife near the back entrance to her apartment building and again in the hallway inside her apartment building. When the attack occurred, she screamed for help numerous times and eventually died from her stab wounds.

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Construction of a Compact Low-Cost Radiation Shield for Air-Temperature Sensors in Ecological Field Studies

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Models for the bystander effect in gradient radiation fields: Range and signalling type.

Valery Peng¹, Natalka Suchowerska², Ana Dos Santos Esteves³

¹School of Physics, University of Sydney, Building A28 Physics Road, NSW 2006, Australia.

Journal of Theoretical Biology

|July 17, 2018

Summary

Bystander effects in radiation therapy improve cancer cell killing. This study developed predictive models showing that radiation field modulation, controlling bystander signals, enhances cancer treatment effectiveness.

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Area of Science:

Radiobiology
Radiation Oncology
Computational Biology

Background:

Bystander effects, where cells not directly irradiated are affected, contribute significantly to cell death but are not in the linear-quadratic (LQ) model.
Radiation dose gradients influence bystander signal distribution, offering potential for improved cancer cell killing.
Understanding bystander signaling range and mechanisms is crucial for developing predictive models for radiotherapy.

Purpose of the Study:

To develop and test predictive models incorporating radiation-induced bystander effects.
To investigate the impact of dose gradients and signaling range on cancer cell survival.
To determine if bystander effects can be manipulated through radiation field modulation for enhanced cancer treatment.

Main Methods:

Three models were proposed based on different assumptions of bystander signal range and transmission (short-range, diffusion-based, and long-range).
Models were fitted to experimental data of cancer cell survival in uniform and modulated radiation fields.
Model predictions for local survival and dose-response were validated using independent datasets.

Main Results:

All tested models demonstrated improved fits compared to the classical LQ model.
Model 2 showed the best fit with a specific bystander effect sign.
Model 3 provided the best overall fit for average survival and the most accurate predictions for modulated fields.

Conclusions:

Bystander effects in radiation therapy can be effectively modeled and controlled.
Radiation field modulation, by influencing bystander signal distribution, offers a promising strategy to enhance cancer treatment efficacy.
Further research into bystander signaling mechanisms can refine radiotherapy planning and improve patient outcomes.