Achievement of Target Gain Larger than Unity in an Inertial Fusion Experiment

On December 5, 2022, an indirect drive fusion implosion on the National Ignition Facility (NIF) achieved a target gain G_{target} of 1.5. This is the first laboratory demonstration of exceeding "scientific breakeven" (or G_{target}>1) where 2.05 MJ of 351 nm laser light produced 3.1 MJ of total fusion yield, a result which significantly exceeds the Lawson criterion for fusion ignition as reported in a previous NIF implosion [H. Abu-Shawareb et al. (Indirect Drive ICF Collaboration), Phys. Rev. Lett. 129, 075001 (2022)PRLTAO0031-900710.1103/PhysRevLett.129.075001]. This achievement is the culmination of more than five decades of research and gives proof that laboratory fusion, based on fundamental physics principles, is possible. This Letter reports on the target, laser, design, and experimental advancements that led to this result.

Lawson Criterion for Ignition Exceeded in an Inertial Fusion Experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion.

Observation of persistent species temperature separation in inertial confinement fusion mixtures

The injection and mixing of contaminant mass into the fuel in inertial confinement fusion (ICF) implosions is a primary factor preventing ignition. ICF experiments have recently achieved an alpha-heating regime, in which fusion self-heating is the dominant source of yield, by reducing the susceptibility of implosions to instabilities that inject this mass. We report the results of unique separated reactants implosion experiments studying pre-mixed contaminant as well as detailed high-resolution three-dimensional simulations that are in good agreement with experiments. At conditions relevant to mixing regions in high-yield implosions, we observe persistent chunks of contaminant that do not achieve thermal equilibrium with the fuel throughout the burn phase. The assumption of thermal equilibrium is made in nearly all computational ICF modeling and methods used to infer levels of contaminant from experiments. We estimate that these methods may underestimate the amount of contaminant by a factor of two or more.

Genetic rescue, the greater prairie chicken and the problem of conservation reliance in the Anthropocene

A central question in conservation is how best to manage biodiversity, despite human domination of global processes (= Anthropocene). Common responses (i.e. translocations, genetic rescue) forestall potential extirpations, yet have an uncertain duration. A textbook example is the greater prairie chicken (GRPC: Tympanuchus cupido pinnatus), where translocations (1992-1998) seemingly rescued genetically depauperate Illinois populations. We re-evaluated this situation after two decades by genotyping 21 microsatellite loci from 1831 shed feathers across six leks in two counties over 4 years (2010-2013). Low migration rates (less than 1%) established each county as demographically independent, but with declining-population estimates (4 year average N = 79). Leks were genetically similar and significantly bottlenecked, with low effective population sizes (average N_e = 13.1; 4 year N_e/N = 0.166). Genetic structure was defined by 12 significantly different family groups, with relatedness r = 0.31 > half-sib r = 0.25. Average heterozygosity, indicating short-term survival, did not differ among contemporary, pre- and post-translocated populations, whereas allelic diversity did. Our results, the natural history of GRPC (i.e. few leks, male dominance hierarchies) and its controlled immigration suggest demographic expansion rather than genetic rescue. Legal protection under the endangered species act (ESA) may enhance recovery, but could exacerbate political-economic concerns on how best to manage 'conservation-reliant' species, for which GRPC is now an exemplar.

Anthropogenic impacts drive niche and conservation metrics of a cryptic rattlesnake on the Colorado Plateau of western North America

Ecosystems transition quickly in the Anthropocene, whereas biodiversity adapts more slowly. Here we simulated a shifting woodland ecosystem on the Colorado Plateau of western North America by using as its proxy over space and time the fundamental niche of the Arizona black rattlesnake (Crotalus cerberus). We found an expansive (= end-of-Pleistocene) range that contracted sharply (= present), but is blocked topographically by Grand Canyon/Colorado River as it shifts predictably northwestward under moderate climate change (= 2080). Vulnerability to contemporary wildfire was quantified from available records, with forested area reduced more than 27% over 13 years. Both 'ecosystem metrics' underscore how climate and wildfire are rapidly converting the Plateau ecosystem into novel habitat. To gauge potential effects on C. cerberus, we derived a series of relevant 'conservation metrics' (i.e. genetic variability, dispersal capacity, effective population size) by sequencing 118 individuals across 846 bp of mitochondrial (mt)DNA-ATPase8/6. We identified five significantly different clades (net sequence divergence = 2.2%) isolated by drainage/topography, with low dispersal (F ST = 0.82) and small sizes (2N ef = 5.2). Our compiled metrics (i.e. small-populations, topographic-isolation, low-dispersal versus conserved-niche, vulnerable-ecosystem, dispersal barriers) underscore the susceptibility of this woodland specialist to a climate and wildfire tandem. We offer adaptive management scenarios that may counterbalance these metrics and avoid the extirpation of this and other highly specialized, relictual woodland clades.

[Phylogeography and phenotypic diversity of the pumpkinseed Sunfish Lepomis gibbosus (Linnaeus, 1758) of the Northern Black Sea Coast]

This paper studies the origin and the genetic and morphological diversity of the pumpkinseed sunfish, a North American invader that is actively expanding its range in the Northern Black Sea Coast. Based on an analysis of variability of the nucleotide sequence of the mtDNA cyt b locus, it was found that all populations of the Northern Black Sea Coast (basins of Dnieper, Dniester, and Danube rivers) are represented by one haplotype. Intraspecific variability is absent. Phylogeographic analysis revealed that the most related haplotype is in a population of pumpkinseed sunfish from New Germany Lake in the Potomac Riverbasin (Maryland, United States), which makes it possible to consider it a parent of the investigated populations. Morphological variation oin countable traits was highly homogeneous. Significant differentiation of a sample from the population of the Dnieper Reservoir from the populations of the Danube and Dniester was found for plastic traits of both the body and cranium. Analysis of the trajectories of development showed that the Dnieper is inhabited by a "pelagic" morpho-ecological form of pumpkinseed sunfish, while the Dniester and Danube is inhabited by a "littoral" form. It is suggested that the success of the settlement of this North American species in the Northern Black Sea Coast does not depend on the origin or the level of its genetic diversity but is instead likely to be ensured by the realization of its available discrete morpho-ecological variability.

Permanent genetic resources added to Molecular Ecology Resources Database 1 August 2010-30 September 2010

This article documents the addition of 229 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Acacia auriculiformis × Acacia mangium hybrid, Alabama argillacea, Anoplopoma fimbria, Aplochiton zebra, Brevicoryne brassicae, Bruguiera gymnorhiza, Bucorvus leadbeateri, Delphacodes detecta, Tumidagena minuta, Dictyostelium giganteum, Echinogammarus berilloni, Epimedium sagittatum, Fraxinus excelsior, Labeo chrysophekadion, Oncorhynchus clarki lewisi, Paratrechina longicornis, Phaeocystis antarctica, Pinus roxburghii and Potamilus capax. These loci were cross-tested on the following species: Acacia peregrinalis, Acacia crassicarpa, Bruguiera cylindrica, Delphacodes detecta, Tumidagena minuta, Dictyostelium macrocephalum, Dictyostelium discoideum, Dictyostelium purpureum, Dictyostelium mucoroides, Dictyostelium rosarium, Polysphondylium pallidum, Epimedium brevicornum, Epimedium koreanum, Epimedium pubescens, Epimedium wushanese and Fraxinus angustifolia.

The inpatient neurology consultation service: value and cost

Neurological conditions comprise a significant proportion of patient admissions to hospital but, in the majority of cases, are admitted under the care of non-neurological physicians. As a consequence, neurological ward consultations are commonly requested by the admitting medical teams to review diagnoses and management plans. The outcomes of neurological ward consultations were examined and the time required for the referral process recorded by performing a detailed prospective three-month audit of inpatient referrals to the neurology service. The consultations of 120 patients were recorded, categorised and analysed. These consultations were beneficial in the vast majority of cases, with a clear impact on patient diagnoses or management plans. The consultation process was time consuming, however, both in respect of the initial review, but also with follow-up visits. This audit highlights the importance of neurological input in the diagnosis and management of hospital inpatients. The time taken for this process should be resourced appropriately.

High CSF transforming growth factor beta levels after subarachnoid haemorrhage: association with chronic communicating hydrocephalus

BACKGROUND

Chronic communicating hydrocephalus is a common sequela of subarachnoid haemorrhage and develops when the flow and drainage of CSF are impaired after fibrosis in the subarachnoid space. Released by platelets into the CSF after subarachnoid haemorrhage, transforming growth factor (TGF)beta1/beta2 are potent fibrogenic agents that may promote post-haemorrhagic fibrosis and chronic communicating hydrocephalus.

METHODS

Temporal changes in total (latent plus active) TGFbeta1/beta2 CSF levels of post-haemorrhage patients developing acute hydrocephalus were measured using ELISA to discover if titres were higher in patients that subsequently developed chronic communicating hydrocephalus, compared with those that did not.

RESULTS

Mean (SD) CSF levels of total TGFbeta1 were 97 (42) pg/ml and total TGFbeta2 were 395 (39) pg/ml in control patients with (non-haemorrhagic) hydrocephalus. For days 1-5 post-subarachnoid haemorrhage (dph), levels of 1427 (242) pg/ml and 976 (191) pg/ml were seen for total TGFbeta1 and TGFbeta2, respectively. Beyond 5 dph, total TGFbeta1/beta2 levels declined but remained significantly elevated (p<0.01) above control patient values for at least 19 dph. Haemorrhagic patients that went on to develop chronic communicating hydrocephalus had significantly higher levels of total TGFbeta1 (p<0.01) and TGFbeta2 (p<0.05) between 1 and 9 dph, compared with those of haemorrhagic patients that did not.

CONCLUSIONS

Acutely measured levels of TGFbeta1/beta2 in the CSF of patients with subarachnoid haemorrhage are thus potential prognostic biomarkers for the subsequent development of chronic communicating hydrocephalus, indicating likely dependency on CSF shunting.

X-ray absorption spectroscopy measurements of thin foil heating by Z-pinch radiation

Absorption spectroscopy measurements of the time-dependent heating of thin foils exposed to intense z-pinch radiation sources are presented. These measurements and their analysis provide valuable benchmarks for, and insights into, the radiative heating of matter by x-ray sources. Z-pinch radiation sources with peak powers of up to 160 TW radiatively heated thin plastic-tamped aluminum foils to temperatures approximately 60 eV. The foils were located in open slots at the boundary of z-pinch hohlraums surrounding the pinch. Time-resolved Kalpha satellite absorption spectroscopy was used to measure the evolution of the Al ionization distribution, using a geometry in which the pinch served as the backlighter. The time-dependent pinch radius and x-ray power were monitored using framing camera, x-ray diode array, and bolometer measurements. A three-dimensional view factor code, within which one-dimensional (1D) radiation-hydrodynamics calculations were performed for each surface element in the view factor grid, was used to compute the incident and reemitted radiation flux distribution throughout the hohlraum and across the foil surface. Simulated absorption spectra were then generated by postprocessing radiation-hydrodynamics results for the foil heating using a 1D collisional-radiative code. Our simulated results were found to be in good general agreement with experimental x-ray spectra, indicating that the spectral measurements are consistent with independent measurements of the pinch power. We also discuss the sensitivity of our results to the spectrum of the radiation field incident on the foil, and the role of nonlocal thermodynamic equilibrium atomic kinetics in affecting the spectra.

Upregulated survivin expression in activated T lymphocytes correlates with disease activity in multiple sclerosis

Programmed cell death (apoptosis) is critical for the normal development and homeostasis of the immune system. There is emerging evidence that failure of apoptosis to eliminate potentially pathogenic, autoreactive T lymphocytes may be involved in the pathogenesis of multiple sclerosis (MS). This failure is related to multiple abnormalities of apoptosis-regulatory molecules that involve survivin, a recently described cell cycle-regulated anti-apoptosis protein. In this study, we investigated the relationship between survivin expression in peripheral T lymphocytes and clinical features of MS. We detected a significant over-expression of survivin in mitogen stimulated T lymphocytes from patients with active MS when compared with corresponding expression in patients with stable MS or those with inflammatory and non-inflammatory neurologic disorders. This over-expression of survivin in patients with active MS correlated with cellular resistance to apoptosis and with features of disease activity, such as disease duration and the number of enhanced lesions on cranial magnetic resonance imaging. There was no correlation between cellular survivin levels and the expression of other apoptosis-inhibitory proteins, such as Bcl-2 and Fas-associated death domain-like interleukin-1beta-converting enzyme inhibitory protein (FLIP). Our findings indicate that cellular over-expression of the novel anti-apoptosis protein survivin is a feature of clinically active MS.

Optimal wire-number range for high x-ray power in long-implosion-time aluminum Z pinches

Experiments performed on the 8-MA Saturn accelerator to investigate the effects of interwire gap spacing on long-implosion-time Z pinches have resulted in the observation of a regime of optimal wire number. The experiments varied the wire number of 40 and 32 mm diam arrays, resulting in interwire gaps from 3.9 to 0.36 mm, with fixed mass and length. aluminum K-shell powers up to 3.4 TW were measured, with long, slow rising, lower power x-ray pulses for interwire gaps greater than 2.2 mm and less than 0.7 mm, and short, fast rising, higher power pulses for interwire gaps in the range 0.7-2.2 mm.

Cost effectiveness analysis of a smoke alarm giveaway program in Oklahoma City, Oklahoma

OBJECTIVE

To estimate the cost effectiveness of the Lifesavers Residential Fire and Injury Prevention Program (LRFIPP), a smoke alarm giveaway program.

SETTING

In 1990, the LRFIPP distributed over 10,000 smoke alarms in an area of Oklahoma City at high risk for residential fire injuries. The program also included fire prevention education and battery replacement components.

METHODS

A cost effectiveness analysis was conducted from the societal and health care systems perspectives. The study compared program costs with the total costs of medical treatment and productivity losses averted over a five year period. Fatal and non-fatal residential fire related injuries prevented were estimated from surveillance data. Medical costs were obtained from chart reviews of patients with fire related injuries that occurred during the pre-intervention period.

RESULTS

During the five years post-intervention, it is estimated that the LRFIPP prevented 20 fatal and 24 non-fatal injuries. From the societal perspective, the total discounted cost of the program was $531,000. Total discounted net savings exceeded $15 million. From the health care system perspective, the total discounted net savings were almost $1 million and would have a net saving even if program effectiveness was reduced by 64%.

CONCLUSIONS

The program was effective in reducing fatal and non-fatal residential fire related injuries and was cost saving. Similar programs in other high risk areas would be good investments even if program effectiveness was lower than that achieved by the LRFIPP.

Child abuse and neglect: a public health perspective

Child abuse and neglect prevention are now poised at the threshold of the public health arena just as the prevention of communicable diseases and unintentional injuries once stood. The principles of public health combined with epidemiology helped eradicate smallpox. The expertise of many disciplines and the three-pronged (primary, secondary, and tertiary) prevention approach have moved the concept of unintentional injuries from "accidents will happen" to predictable and, therefore, preventable. Child abuse and neglect are now seen as epidemic in society. Through surveillance, intervention, prevention, and policy changes, the rate of child abuse and neglect can be significantly impacted in the same way that rates of unintentional injuries and communicable diseases have been reduced.

Holarctic phylogeography of Arctic charr (Salvelinus alpinus L.) inferred from mitochondrial DNA sequences

This study evaluated mitochondrial DNA (mtDNA) sequence variation in a 552-bp fragment of the control region of Arctic charr (Salvelinus alpinus) by analyzing 159 individuals from 83 populations throughout the entire range of the complex. A total of 89 (16.1%) nucleotide positions were polymorphic, and these defined 63 haplotypes. Phylogenetic analyses supported the monophyly of the complex and assigned the observed haplotypes to five geographic regions that may be associated with different glacial refugia. Most notably, a formerly defined major evolutionary lineage (S. a. erythrinus) ranging from North America across the Arctic archipelago to the Eurasian continent has now been partitioned into the Arctic group and the newly identified Siberian group. The Beringian group, formed entirely by specimens assigned to S. malma (Dolly Varden), encompassed the area formerly assigned to S. a. taranetzi. The latter, due to a unique haplotype, became the basal member of the Arctic group. Overall, the S. alpinus complex reflects divergent evolutionary groups coupled with shallow intergroup differentiation, also indicated by an analysis of molecular variance that attributed 73.7% (P < 0.001) of the total genetic variance among groups. Time estimates, based on sequence divergence, suggest a separation of the major phylogeographic groups during early to mid-Pleistocene. In contrast, colonization of most of today's range started relatively recently, most likely late Pleistocene during the last retreat of ice sheets some 10,000-20,000 years ago. This time scale obviously is too shallow for detecting significant variation on a smaller scale using mtDNA markers. However, other studies using nuclear microsatellite DNA variation strongly suggested ongoing evolution within groups by revealing strong population-genetic substructuring and restricted gene flow among populations. Thus, Arctic charr could serve as a model organism to investigate the linkage between historical and contemporary components of phylogeographic structuring in fish, and, with a global perspective of the distribution of genetic variation as a framework, meaningful comparisons of charr studies at a smaller geographic scale will now be possible.

Predictors of systolic augmentation from left ventricular preexcitation in patients with dilated cardiomyopathy and intraventricular conduction delay

BACKGROUND

VDD pacing can enhance systolic function in patients with dilated cardiomyopathy and discoordinate contraction; however, identification of patients likely to benefit is unclear. We tested predictors of systolic responsiveness on the basis of global parameters as well as directly assessed mechanical dyssynchrony.

METHODS AND RESULTS

Twenty-two DCM patients with conduction delay were studied by cardiac catheterization with a dual-sensor micromanometer to measure LV and aortic pressures during sinus rhythm and LV free-wall pacing. Pacing enhanced isovolumetric (dP/dt(max)) and ejection-phase (pulse pressure, PP) systolic function by 35+/-21% and 16.4+/-11%, respectively, and these changes correlated directly (r=0.7, P=0.001). %DeltadP/dt(max) was weakly predicted by baseline QRS (r=0.6, P<0.02), more strongly by baseline dP/dt(max) (r=0.7, P=0.001), and best by bidiscriminate analysis combining baseline dP/dt(max) < or =700 mm Hg/s and QRS > or =155 ms to predict %DeltadP/dt(max) > or =25% and %DeltaPP > or =10% (P<0.0005, chi(2)), with no false-positives. Benefit could not be predicted by %DeltaQRS. To test whether basal mechanical dyssynchrony predicted responsiveness to LV pacing, circumferential strains were determined at approximately 80 sites throughout the LV by tagged MRI in 8 DCM patients and 7 additional control subjects. Strain variance at time of maximal shortening indexed dyssynchrony, averaging 28.0+/-7.1% in normal subjects versus 201.4+/-84.3% in DCM patients (P=0.001). Mechanical dyssynchrony also correlated directly with %DeltadP/dt(max) (r=0.85, P=0.008). Conclusions-These results show that although mechanical dyssynchrony is a key predictor for pacing efficacy in DCM patients with conduction delay, combining information about QRS and basal dP/dt(max) provides an excellent tool to identify maximal responders.

Estimating the proportion of homes with functioning smoke alarms: a comparison of telephone survey and household survey results

OBJECTIVES

This study determined the proportion of homes with functioning smoke alarms in a low-income area experiencing a high rate of residential fire-related injuries.

METHODS

An on-site survey of households was conducted to confirm the results of a telephone survey.

RESULTS

In the telephone survey, 71% of households reported having functioning smoke alarms. In the household survey, 66% of households reported having functioning alarms; however, when the alarms were tested, the percentage dropped to 49%.

CONCLUSIONS

Telephone surveys may overestimate the presence of functioning smoke alarms in some populations. Thus, the use of telephone surveys to establish baseline measures could significantly affect the evaluation of smoke-alarm giveaway programs.

Differential association of cytoplasmic signalling molecules SHP-1, SHP-2, SHIP and phospholipase C-gamma1 with PECAM-1/CD31

Recent studies have shown that, in addition to its role as an adhesion receptor, platelet endothelial cell adhesion molecule 1/CD31 becomes phosphorylated on tyrosine residues Y663 and Y686 and associates with protein tyrosine phosphatases SHP-1 and SHP-2. In this study, we screened for additional proteins which associate with phosphorylated platelet endothelial cell adhesion molecule 1, using surface plasmon resonance. We found that, besides SHP-1 and SHP-2, platelet endothelial cell adhesion molecule 1 binds the cytoplasmic signalling proteins SHIP and PLC-gamma1 via their Src homology 2 domains. Using two phosphopeptides, NSDVQpY663TEVQV and DTETVpY686SEVRK, we demonstrate differential binding of SHP-1, SHP-2, SHIP and PLC-gamma1. All four cytoplasmic signalling proteins directly associate with cellular platelet endothelial cell adhesion molecule 1, immunoprecipitated from pervanadate-stimulated THP-1 cells. These results suggest that overlapping immunoreceptor tyrosine-based inhibition motif/immunoreceptor tyrosine-based activation motif-like motifs within platelet endothelial cell adhesion molecule 1 mediate differential interactions between the Src homology 2 containing signalling proteins SHP-1, SHP-2, SHIP and PLC-gamma1.

Evaluation of three smoke detector promotion programs

CONTEXT

Seventy percent of U.S. residential fire deaths occur in homes without a working smoke detector. To help prevent residential fire deaths, many programs have distributed or installed detectors in unprotected homes. Because persons receiving a detector may not install it and because detector batteries require annual replacement, the enduring effectiveness of these programs may be questioned.

OBJECTIVE

We evaluated the long-term functional status of smoke detectors distributed to high-risk households in eight areas of Minnesota, Cherokee County (North Carolina), and Oklahoma City (Oklahoma).

DESIGN

Cross-sectional.

SETTING

Home visits were made to check the detectors that were distributed 3 to 4 years earlier.

PARTICIPANTS

Randomly selected households from the three detector promotion programs. MAIN OUT-COME MEASURE: At least one working smoke detector.

RESULTS

Participation rates ranged from 72% to 82%. The percentage of evaluation households with at least one working detector ranged from 58% in Oklahoma to 73% in North Carolina. In 76% of households with nonworking detectors, the batteries were either missing or disconnected. When batteries in nonworking detectors were replaced, 83% of the detectors regained function.

CONCLUSIONS

Future programs should consider distributing detectors that do not require annual battery changes or find effective ways to ensure that batteries are routinely replaced. Programs should also provide each household with the number of detectors needed to meet the most current recommended standard of the National Fire Protection Agency. The evaluation's participation rates support the practicality of unannounced home visits to evaluate home injury prevention programs in high-risk groups.

Comparison of community based smoke detector distribution methods in an urban community

OBJECTIVES

Various methods of soliciting participation for a large smoke detector giveaway program were tested to determine the most effective method of distributing smoke detectors to a high risk urban population.

SETTING

The target area was a 24 square mile (62 km2) section on the south side of Oklahoma City where 16% (73,301) of the city's population resided in 16% (34,845) of the dwellings (excluding apartments). Of the 66 persons in Oklahoma City who were injured in residential fires from September 1987 to April 1990, 45% (30) were in the target area. Of the target area injuries, 47% resulted from fires started by children playing with fire (fireplay).

METHODS

The number of homes without detectors was estimated by telephone survey. Four different methods of soliciting participants were used, including notifying residents by mail; placing flyers on the doors of every habitable residence; and displaying flyers at public places (grocery stores, convenience stores, restaurants, etc). Each of these methods alerted residents that free smoke detectors were available at specific fire stations. The fourth method was distributing detectors door-to-door (canvassing).

RESULTS

The canvassing method resulted in significantly more smoke detectors being distributed to homes without detectors (107%) than any of the three other methods (18%) (p < 0.00001). The canvassing method distributed detectors to 31% of the total target homes, compared with 5% with the other methods (p < 0.00001). Canvassing also resulted in the lowest estimated cost per detector distributed ($1.96) (all other methods, $3.95), and in the largest number distributed per volunteer hour (5.9 v 3.1 detectors per hour by other methods).

CONCLUSIONS

Distributing smoke detectors directly to homes (canvassing) was the most effective and cost efficient method to reach high risk urban residents.

Osmotic stress activates phosphatidylinositol-3,5-bisphosphate synthesis

Inositol phospholipids play multiple roles in cell signalling systems. Two widespread eukaryotic phosphoinositide-based signal transduction mechanisms, phosphoinositidase C-catalysed phosphatidylinositol-4,5-bisphosphate (PtdIns(4,5)P2) hydrolysis and 3-OH kinase-catalysed PtdIns(4,5)P2 phosphorylation, make the second messengers inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) sn-1,2-diacylglycerol and PtdIns(3,4,5)P3. In addition, PtdIns(4,5)P2 and PtdIns3P have been implicated in exocytosis and membrane trafficking. We now show that when the yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe are hyperosmotically stressed, they rapidly synthesize phosphatidylinositol-3,5-bisphosphate (PtdIns(3,5)P2) by a process that involves activation of a PtdIns3P 5-OH kinase. This PtdIns(3,5)P2 accumulation only occurs in yeasts that have an active vps34-encoded PtdIns 3-OH kinase, showing that this latter kinase makes the PtdIns3P needed for PtdIns(3,5)P2 synthesis and indicating that PtdIns(3,5)P2 may have a role in sorting vesicular proteins. PtdIns(3,5)P2 is also present in mammalian and plant cells: in monkey Cos-7 cells, its labelling is inversely related to the external osmotic pressure. The stimulation of a PtdIns3P 5-OH kinase-catalysed synthesis of PtdIns(3,5)P2, a molecule that might be a new type of phosphoinositide 'second messenger, thus appears to be central to a widespread and previously uncharacterized regulatory pathway.

Esophageal foreign bodies: safety and efficacy of Foley catheter extraction of coins

OBJECTIVE

Continued controversy over the role of fluoroscopically guided Foley catheter removal of esophageal foreign bodies has limited the use of this technique despite its significant economic advantages. We reviewed our experience for the safety, efficacy, and applicability of this technique with pediatric patients who had swallowed coins.

MATERIALS AND METHODS

We retrospectively reviewed 10 years of experience with pediatric patients who had undergone fluoroscopically guided Foley catheter removal of coins. All the pediatric patients with a suspected esophageal foreign body were first evaluated by plain film radiography. Foley catheter extraction was attempted when a radiopaque coin was seen and the patient lacked signs of significant esophageal edema resulting in tracheal compromise. During the 10 years covered by our review, 14 pediatric radiologists with specific training in the Foley catheter technique were involved in such removals. A separate review (of consecutive pediatric patients who had a history of or symptoms suggesting ingestion of a foreign body) focused on the percentage of these patients in which the Foley catheter technique was used.

RESULTS

Of the 337 coin extractions attempted using a Foley catheter, coin extraction was successful in 322 (96%) of 337 patients. No complications were encountered. Our focused review found 422 consecutive patients who had undergone radiography to rule out foreign bodies. A radiopaque object was found in 249 (59%) of 422 patients. Of these 249 objects, 208 (84%) were ingested coins. Of 208 coins, 123 (59%) were retained in the esophagus; of these 123 coins retained in the esophagus, 116 (94%) were amenable to fluoroscopically guided Foley catheter extraction.

CONCLUSION

Fluoroscopically guided Foley catheter extraction of retained coins in pediatric patients who lack evidence of significant esophageal edema causing tracheal compromise is a safe and efficacious technique. It should be considered the technique of choice for such extractions.

Substance abuse and the nurse manager: ethical and legal issues

Nurse managers have a pivotal role in intervening in situations of substance abuse among employees. This article addresses ethical and legal dimensions of chemical impairment from the perspective of the nurse manager. The value of a rehabilitative rather than a punitive approach to the chemically impaired nurse is emphasized. Ethics of care and relevant legal considerations, including the Americans With Disabilities Act, are explored through case analysis. Covenantal relationships offer a framework for examining the responsibilities of the nurse manager with respect to the community, employer, the actual or allegedly chemically impaired nurse, and one's self.