Magnetic resonance imaging markers of suicide attempt and suicide risk in adolescents.

More than 36,000 people in the United States die from suicide annually, and suicide is the third leading cause of death in adolescence. Adolescence is a time of high risk for suicidal behavior, as well as a time that intervention and treatment may have the greatest impact because of structural brain changes and significant psychosocial development during this period. Functional and structural neuroimaging studies in adults who have attempted suicide suggest distinct gray matter volume abnormalities in cortical regions, as well as prefrontal cortical and dorsal anterior cingulate gyrus neural circuitry differences compared with affective and healthy adult controls. Recent functional neuroimaging studies in adolescents with a history of suicide attempt suggest differences in the attention and salience networks compared with adolescents with depression and no history of suicide attempt and healthy controls when viewing angry faces. In contrast, no abnormalities are seen in these areas in the absence of emotional stimuli. These networks may represent promising targets for future neuroimaging studies to identify markers of risk for future suicide attempt in adolescents.

A comparison of DNA repair and survival of Escherichia coli O157:H7 following exposure to both low- and medium-pressure UV irradiation.

DNA repair and survival of pathogenic E. coli O157:H7 was investigated following exposure to ultraviolet (UV) radiation from both low-pressure (LP) and medium-pressure (MP) lamps. This study included irradiation at UV doses used in drinking water treatment and lower doses indicative of potential treatment problems. Immediately following UV exposure, an average log inactivation of 4.5 or greater was observed following all tested doses of LP (5, 8, 20 and 40 mJ/cm(2)) or MP UV (5 and 8 mJ/cm(2)) indicating the sensitivity of E. coli O157:H7 to UV irradiation. Following conditions conducive to repair, maximum photo repair occurred rapidly within 30 minutes after low doses (5 and 8 mJ/cm(2)) of LP UV. The rate of repair was much higher than reported previously in non-pathogenic E. coli (which occurred within 2 hours). In contrast to LP UV, limited photo repair of E. coli O157:H7 was observed following MP UV exposure at reduced doses (5 and 8 mJ/cm(2)). At these lower doses, low levels of light independent repair were observed following LP UV, but not following exposure of MP UV irradiation. This study indicates that MP UV may enhance UV disinfection of E. coli O157:H7 by reducing the ability to repair following non-ideal treatment conditions. Following doses used in drinking water treatment (20 and 40 mJ/cm(2)), low levels of photo repair following LP UV were evident.