Explore the vast range of titles available.

Some X-ray free-electron laser facilities are pushing towards sub-10 fs pulses, making it desirable to reduce errors in X-ray/optical delay measurements to the 1 fs level. Researchers have now demonstrated X-ray measurements with a temporal resolution shorter than 1 fs, opening up new possibilities for time-resolved X-ray experiments. Today's brightest coherent X-ray sources, X-ray free-electron lasers, produce ultrafast X-ray pulses for which full-width at half-maximum durations as short as 3 fs have been measured 1 . There has been a marked increase in the popularity of such short pulses now that optical timing techniques have begun to report an X-ray/optical delay below ∼10 fs r.m.s. errors. As a result, sub-10 fs optical pulses have been implemented at the Linac Coherent Light Source (LCLS) X-ray beamlines, thus warranting a push to reduce the error in X-ray/optical delay measurements to the 1 fs level. Here, we report a unique two-dimensional spectrogram measurement of the relative X-ray/optical delay. This easily scalable relative delay measurement already surpasses previous techniques by an order of magnitude with its sub-1 fs temporal resolution and opens up the prospect of time-resolved X-ray measurements to the attosecond community.

The proto-oncogene bcl-2 inhibits apoptotic and necrotic neural cell death. Expression of Bcl-2 in the GT1-7 neural cell line prevented death as a result of glutathione depletion. Intracellular reactive oxygen species and lipid peroxides rose rapidly in control cells depleted of glutathione, whereas cells expressing Bcl-2 displayed a blunted increase and complete survival. Modulation of the increase in reactive oxygen species influenced the degree of cell death. Yeast mutants null for superoxide dismutase were partially rescued by expression of Bcl-2. Thus, Bcl-2 prevents cell death by decreasing the net cellular generation of reactive oxygen species.

The protooncogene bcl-2, which has been implicated in B-cell lymphoma development, inhibits apoptosis due to growth factor withdrawal in some, but not all, hematopoietic cells. Recently we found that bcl-2 also inhibits apoptosis in PC12 pheochromocytoma cells. We now report that bcl-2 inhibits the death of a central neural cell line due to serum and growth factor withdrawal, the calcium ionophore A23187, glucose withdrawal, membrane peroxidation, and, in some cases, free radical-induced damage. This broad range of protective effects of BCL-2 protein suggests that BCL-2 may interact with a central step in neural cell death. Measurements of intracellular free calcium suggest that BCL-2 alters the transduction of neural death signals at a point distal to the rise in intracellular free calcium.

Neuregulins are ligands for the erbB family of receptor tyrosine kinases and mediate growth and differentiation of neural crest, muscle, breast cancer, and Schwann cells. Neuregulins contain an epidermal growth factor-like domain located C-terminally to either an Ig-like domain or a cysteine-rich domain specific to the sensory and motor neuronderived isoform. Here it is shown that elimination of the Ig-like domain-containing neuregulins by homologous recombination results in embryonic lethality associated with a deficiency of ventricular myocardial trabeculation and impairment of cranial ganglion development. The erbB receptors are expressed in myocardial cells and presumably mediate the neuregulin signal originating from endocardial cells. The trigeminal ganglion is reduced in size and lacks projections toward the brain stem and mandible. We conclude that IgL-domain-containing neuregulins play a major role in cardiac and neuronal development.

A unique, ultra-sensitive frequency-resolved optical gating system was constructed, and the pulse shape and chirp of a quantum-dot mode-locked laser was unambiguously measured using this technique for the first time. A clear pulse asymmetry was detected, and evidence that the pulses are recompressible to sub-picosecond lengths is presented.

This purpose of the study was to examine the factors associated with access to routine care and to specialty care for Mississippi children with special health care needs (CSHCN). We analyzed data for Mississippi CSHCN from the 2001 National Survey of Children with Special Health Care Needs. Using a modified version of Andersen and Aday's Behavioral Model of Health Services Use, we explored the relationship of independent variables (e.g., demographics, insurance, severity of illness) to dependent variables (did not obtain routine care, did not obtain specialty care). We conducted bivariate and logistic regression analyses using SAS and SUDAAN. Based on self-reported data, with a 61% response rate, 66% of Mississippi CSHCN needed routine health care, and 52.8% needed specialty care. Of these children, 6.5% did not receive routine care and 9.3% did not receive specialty care. In a fully adjusted model, discontinuous insurance coverage was an important factor associated with not having obtained routine care (OR = 7.8; CI = 1.7-35.9) and specialty care (OR = 8.6; CI = 2.0-36.8). Children with a high illness severity rank were more likely to have not obtained routine care than children with a low rank (OR 1.4; CI = 1.1-1.9). It may be important to establish a health insurance safety net for families who lack insurance continuity since it appears that a lapse in insurance coverage impedes health care access. Further research is needed to understand the relationship between illness severity and lack of health care access, especially for children with special health care needs.

The objective of this study was to describe the presentation and outcome of children with intracranial tumours under 1 year of age, and to compare the results with a previous cohort from the same paediatric neurosurgical unit. It is a retrospective review of all children under 1 year of age presenting with intracranial tumours between 1982 and 1997, with follow-up data from a multidisciplinary paediatric neuro-oncology clinic. Seventy-five children were diagnosed during the period of study. Overall survival at 5 years was 56% (31 of 55 eligible children), half of whom are in mainstream education. Earlier diagnosis and a dramatic reduction in peri-operative mortality compared to our previous cohort account for the improvements in the results of treatment for these children whose care can only be properly managed in a specialized paediatric oncology centre.

Editor: Three cheers for Delegate Willie Rush for having the guts to introduce H.B. 1063. This type of sentence--public whipping --should be mandatory for muggers, attempted robbery, refusal to pay child support, molestation of people (criminally assaulting boys,...