A multi-terawatt two-color beam for high-power field-controlled nonlinear optics.

Two-color laser beams are instrumental in light-field control and enhancement of high-order harmonic, spectral supercontinuum, and terahertz radiation generated in gases, plasmas, and solids. We demonstrate a multi-terawatt two-color beam produced using a relativistic plasma mirror, with 110 mJ at 800 nm and 30 mJ at 400 nm. Both color components have high spatial quality and can be simultaneously focused, provided that the plasma mirror lies within a Rayleigh range of the driving fundamental beam. Favorable scaling of second-harmonic generation by plasma mirrors at relativistic intensities suggests them as an excellent tool for multi-color waveform synthesis beyond the petawatt level.

Randomised controlled trial of patient controlled analgesia compared with nurse delivered analgesia in an emergency department.

OBJECTIVE: To compare effectiveness, safety, and patient satisfaction of patient controlled analgesia (PCA) with titrated, intravenous opioid injections for the management of acute traumatic pain in the emergency department (ED). METHODS: The study took place in the ED of a teaching hospital. Patients suffering traumatic injury requiring opioid analgesia, and meeting other inclusion criteria, were consented and randomised to either the study group or control group. The study group were given morphine through the PCA system, whereas the control group were given morphine via the conventional route of nurse titration. Pain levels were measured using a visual analogue scale. Both groups had their vital signs (blood pressure, pulse, oxygen saturations, Glasgow coma score, respiratory rate) and pain scores monitored at 0, 15, 30, 45, 60, 90, and 120 minutes, and any adverse events were noted. Patients were followed up with a questionnaire asking about their experience of pain relief in the department. RESULTS: 86 patients were recruited to the study, 43 in each group. There was no significant difference between the groups in terms of pain relief (p = 0.578) and patient satisfaction (p = 0.263). No severe adverse events were observed, although 20.7% (n = 9) of the PCA group experienced mild sedation compared with 7% (n = 3) of the control group. CONCLUSIONS: PCA is at least as effective as titrated intravenous injections for relief of traumatic pain. It has considerable potential for use in the ED.