The statement of the title is proved. It implies that under physically reasonable conditions, spacetimes which are free from singularities are necessarily stably causal and hence admit a time function. Read as a singularity theorem it states that if there is some form of causality violation on spacetime then either it is the worst possible, namely violation of chronology, or there is a singular...

The global cervical cancer burden falls disproportionately upon women in low and middle-income countries. Insufficient infrastructure, lack of access to preventive HPV vaccines, screening, and treatment, as well as limited trained personnel and training opportunities, continue to impede efforts to reduce incidence and mortality in these nations. These hurdles have been substantial challenges to...

Accumulated external radiation doses of residents near the Semipalatinsk nuclear test site of the former USSR are presented as a results of study by the thermoluminescence technique for bricks sampled at several settlements in 1995 and 1996. The external doses that we evaluated from exposed bricks were up to about 100 cGy for resident. The external doses at several points in the center of Semip...

Standard radiation therapy for patients undergoing primary chemosensitized radiation for carcinomas of the cervix usually consists of external beam radiation followed by an intracavitary brachytherapy boost. On occasion, the brachytherapy boost cannot be performed due to unfavorable anatomy or because of coexisting medical conditions. We examined the safety and efficacy of using CyberKnife ster...

background and objective: hypothyroidism is a known consequence of the external beam radiotherapy to the neck encompassing the thyroid gland for over 40 years. the aim of this study was to find out the incidence of hypothyroidism in patients with head and neck cancer treated with radiotherapy, when radiation portals included whole of the thyroid gland. materials and methods: this prospective no...

most popular sources for electromagnetic waves. however, there are many concerns regarding their biological effects on the body, especially the central nervous system. therefore, the aim of this study was to evaluate the effects of cell phone radiation on histology of the cerebellar granular cells in the neonatal rat. materials and methods: we selected some wistar rats. then, we randomly divide...

Background: Ionizing radiation is present in all environment of the Earth’s surface, beneath the Earth and in the atmosphere. Human beings are exposed to external radiation from their surroundings naturally and also to internal radiation from food, water and air they consume. Then, it is important to measure and develop knowledge about radiation. Objective: This study is designed to evalu...

External radiation seems to be associated with increased amounts of cytokines and other cellular modulators. Impaired microcirculation and fibrosis are examples of typical long term damage caused by radiotherapy. Adipose tissue-derived stem cells (ASC) are discussed to enhance wound healing, but their role in wounds due to radiotherapy is poorly understood. Normal human fibroblasts (NHF) and AS...