Limitations in ionization-induced compression of femtosecond laser pulses due to spatio-temporal couplings

It was recently proposed that ionization-induced self-compression could be used as an effective method to further compress femtosecond laser pulses propagating freely in a gas jet [He et al., Phys. Rev. Lett. 113, 263904 2014]. Here, we address the question of the homogeneity of the self-compression process and show experimentally that homogeneous self-compression down to 12fs can be obtained by finding the appropriate focusing geometry for the laser pulse. Simulations are used to reproduce the experimental results and give insight into the self-compression process and its limitations. Simulations suggest that the ionization process induces spatio-temporal couplings which lengthen the pulse duration at focus, possibly making this method ineffective for increasing the laser peak intensity.

[Nursing as a situative activity. A realistic concept for the assurance of quality and efficiency in geriatric care]

In institutional care for the elderly effective and efficient professional action is needed as well as in acute care settings. That means rational-systematic acting. This includes the establishment of goals, systematic planning and realization of these plans, deductive-logical thinking, objective perception and gaining an unbiased objective relationship towards the work to be done. However, an explorative investigation of the ways, how successful and experienced nurses do their job-being viewed by their colleagues as qualitatively effective and efficient concerning their time budget-provides the following results. In direct care procedures which go beyond rational-systematic action prove to be more economic and successful. This type of action is characterized by interactive procedures of dialogical nature, the patterns of rationality tend to be associative, the perception of the elderly to be taken care of can be considered as intuitive-subjective and the relationship towards them as personal-empathic. Those patterns of professional action we refer to as "subjectifying" or "situative" patterns of action. They can also be found in the process of an artist's work. The consequences of this change of paradigma concerning training and cost-effective nursing are discussed in this paper.

Contrast media algogenic potential in peripheral arteriography. Potentiation of bradykinin-induced pain in the rat

RATIONALE AND OBJECTIVES

Contrast media (CM) with minimal algogenic (pain causing) potential in animal models of peripheral arteriography are still able to produce vascular pain in humans; the poor predictive value of preclinical evaluation led us to develop a more sensitive method based on CM potentiation of bradykinin effects in the rat.

METHODS

Behavioral pain responses and histologic alterations of the arteries were determined after intrafemoral injection of bradykinin to saline- or CM-pretreated rats. Pain reactions were compared with those elicited by single and repeated CM injections.

RESULTS

Contrast media enhanced bradykinin-induced pain was dose dependent with the following potency order: iopamidol > iopromide > ZK 139129 > ZK 119095. Vasodilation and alterations of the arterial internal layer also were seen. Iopromide produced this sensitization at doses that did not elicit evident pain reactions per se.

CONCLUSION

The method proved to be a highly sensitive preclinical discriminant of CM algogenic potential.