Note: three-dimensional stereolithography for millimeter wave and terahertz applications

Metal-coated polymers shaped by 3D stereolithography are introduced as a new manufacturing method for passive components for millimeter to terahertz electromagnetic waves. This concept offers increased design capabilities and flexibilities while shortening the manufacturing process of complex shapes, e.g., corrugated horns, mirrors, etc. Tests at 92.5, 140, and 170 GHz are reported.

Young hippocampal neurons are critical for recent and remote spatial memory in adult mice

New granule cells are continuously generated throughout adulthood in the mammalian hippocampus. These newly generated neurons become functionally integrated into existing hippocampal neuronal networks, such as those that support retrieval of remote spatial memory. Here, we sought to examine whether the contribution of newly born neurons depends on the type of learning and memory task in mice. To do so, we reduced neurogenesis with a cytostatic agent and examined whether depletion of young hippocampal neurons affects learning and/or memory in two hippocampal-dependent tasks (spatial navigation in the Morris water maze and object location test) and two hippocampal-independent tasks (cued navigation in the Morris water maze and novel object recognition). Double immunohistofluorescent labeling of the birth dating marker 5-bromo-2'deoxyuridine (BrdU) together with NeuN, a neuron specific marker, was employed to quantify reduction of hippocampal neurogenesis. We found that depletion of young adult-generated neurons alters recent and remote memory in spatial tasks but spares non-spatial tasks. Our findings provide additional evidence that generation of new cells in the adult brain is crucial for hippocampal-dependent cognitive functions.

Real-time feedback control of millimeter-wave polarization for LHD

Electron cyclotron heating (ECH) is widely used in magnetic fusion devices, and the polarization of the injected millimeter-wave beams plays a crucial role in the propagation and absorption of the beam energy by the plasma. This polarization can be adjusted by grating mirror polarizers placed in the transmission lines which carry the microwaves from the power source to the plasma. In long-pulse devices such as the Large Helical Device (LHD) and ITER, it is desirable to track changes in the plasma and adjust the polarization of the ECH in real time such as to keep the absorption as high as possible and avoid shine-through which may lead to overheating of vessel components. For this purpose a real-time feedback control scheme is envisioned in which a measure of the absorption efficiency can be used to adjust the orientation of the polarizing mirrors toward an optimum. Such a setup has been tested in a low-power test stand as preparation for future implementation in the LHD ECH system. It is shown that a simple search algorithm is efficient and can in principle be used to control either the absorption efficiency or the linear polarization angle.

Roughness of a tilted anharmonic string at depinning

We consider the discretized model of a driven string with an anharmonic elastic energy, in a two-dimensional random potential, as introduced by [Phys. Rev. Lett. 87, 187002 (2001)]]. Using finite size scaling, we numerically compute the roughness of the string in a uniform applied force at the critical depinning threshold. By considering a string with a net average tilt, we demonstrate that the anharmonic elastic energy crosses the model over to the quenched KPZ universality class, in agreement with recent theoretical predictions.

From current-driven to neoclassically driven tearing modes

In the TCV tokamak, the m/n = 2/1 island is observed in low-density discharges with central electron-cyclotron current drive. The evolution of its width has two distinct growth phases, one of which can be linked to a "conventional" tearing mode driven unstable by the current profile and the other to a neoclassical tearing mode driven by a perturbation of the bootstrap current. The TCV results provide the first clear observation of such a destabilization mechanism and reconcile the theory of conventional and neoclassical tearing modes, which differ only in the dominant driving term.

Impact of targeted programs on health systems: a case study of the polio eradication initiative

The results of 2 large field studies on the impact of the polio eradication initiative on health systems and 3 supplementary reports were presented at a December 1999 meeting convened by the World Health Organization. All of these studies concluded that positive synergies exist between polio eradication and health systems but that these synergies have not been vigorously exploited. The eradication of polio has probably improved health systems worldwide by broadening distribution of vitamin A supplements, improving cooperation among enterovirus laboratories, and facilitating linkages between health workers and their communities. The results of these studies also show that eliminating polio did not cause a diminution of funding for immunization against other illnesses. Relatively little is known about the opportunity costs of polio eradication. Improved planning in disease eradication initiatives can minimize disruptions in the delivery of other services. Future initiatives should include indicators and baseline data for monitoring effects on health systems development.

Wilderness mortalities: a 13-year experience

STUDY OBJECTIVE

To analyze the epidemiology of wilderness mortalities in a localized area with diverse terrain.

METHODS

We conducted a retrospective review of the Pima County (Arizona) Sheriff's Office (PCSO) search and rescue logs and case reports, hospital records, and autopsy reports for all wilderness deaths from 1980 to 1992. The study group comprised all victims of injury or illness in Pima County wilderness who died during a 13-year period in a location remote enough so that standard ground-based emergency medical services units could not extract the body.

RESULTS

One hundred fatalities occurred during the 13-year study period. There were 59 unintentional traumas, 18 suicides, 9 homicides, 12 medically related deaths, and 2 deaths of unknown causes. Toxicology tests performed on body fluids yielded positive findings for alcohol in a total of 50 (50%) cases and positive findings for drugs of abuse in 12 (12%) cases. It was estimated that alcohol was "a very probable" or "a probable" causative factor in 23 (40%) of the 59 unintentional trauma deaths, and in 1 (8.3%) of the 12 medically related deaths. Fifty-five (55%) deaths were witnessed events, with 45 (80%) of these victims reported as dying immediately or before arrival of search and rescue personnel. Ten (10%) victims received resuscitation in the field, and according to a review of hospital charts and autopsy reports, only 2 victims had a potentially survivable injury or illness.

CONCLUSION

Many wilderness mortalities are related to incidents involving alcohol. Once the accident or injury has occurred, the majority of deaths are immediate, or at least before the arrival of medical personnel. Higher levels of medical care would not have improved the outcomes of those who did survive long enough to receive medical care. Therefore, primary efforts to reduce mortalities in the wilderness should be directed toward prevention, especially diminishing alcohol use in wilderness areas.

Childhood mortality impact and costs of integrating vitamin A supplementation into immunization campaigns

Country-specific activity and coverage data were used to estimate the childhood mortality impact (deaths averted) and costs of integrating vitamin A supplements into immunization campaigns conducted in 1998 and 1999. More than 94 million doses of vitamin A were administered in 41 countries in 1998, helping to avert nearly 169,000 deaths. During 1999, delivery of more than 97 million doses in 50 countries helped avert an estimated 242,000 deaths. The estimated incremental cost per death averted was US$72 (range: 36-142) in 1998 and US$64 (range: 32-126) in 1999. The estimated average total cost of providing supplementation per death averted was US$310 (range: 157-609) in 1998 and US$276 (range: 139-540) in 1999. Costs per death averted varied by campaign, depending on the number and proportion of the child population reached, number of doses received per child, and child mortality rates.

A tragic report of probable high-altitude pulmonary edema in the Himalayas: preventive implications

High-altitude pulmonary edema (HAPE) is a well-recognized disease entity in trekkers to the Nepal Himalayas. We present the case of a patient who had clinical features consistent with HAPE but did not descend the mountain on time, which contributed to his death. The important factors of the diagnosis, the descent, and the follow-up in Kathmandu are examined.

Steady-state fully noninductive current driven by electron cyclotron waves in a magnetically confined plasma

A steady-state, fully noninductive plasma current has been sustained for the first time in a tokamak using electron cyclotron current drive only. In this discharge, 123 kA of current have been sustained for the entire gyrotron pulse duration of 2 s. Careful distribution across the plasma minor radius of the power deposited from three 0. 5-MW gyrotrons was essential for reaching steady-state conditions. With central current drive, up to 153 kA of current have been fully replaced transiently for 100 ms. The noninductive scenario is confirmed by the ability to recharge the Ohmic transformer. The dependence of the current drive efficiency on the minor radius is also demonstrated.

Polio as a platform: using national immunization days to deliver vitamin A supplements

In 1988 the 41st World Health Assembly committed WHO to the goal of global eradication of poliomyelitis by 2000 "in ways which strengthen national immunization programmes and health infrastructure". The successful use of polio National Immunization Days (NIDs) to deliver vitamin A is an example of how polio eradication can serve as a platform to address other problems of child health. Importantly, this integration is helping to achieve the World Summit for Children goal of eliminating vitamin A deficiency by the year 2000. It is estimated that between 140 million and 250 million preschool children are at risk of subclinical vitamin A deficiency. In 1998 more than 60 million children at risk received vitamin A supplements during polio national immunization days (NIDs). While food fortification and dietary approaches are fundamental to combating vitamin A deficiency, the administration of vitamin A supplements during NIDs helps raise awareness, enhance technical capacity, improve assessment and establish a reporting system. Moreover, polio NIDs provide an entry point for the sustainable provision of vitamin A supplements with routine immunization services and demonstrate how immunization campaigns can be used for the delivery of other preventive health services.

NSAID-induced gastrointestinal toxicity

Recommendations that can be made to decrease the incidence of untoward NSAID-induced GI events include identification of the high-risk patient (Table 3). If it is important to treat these high-risk patients with NSAIDs, either the lowest possible dose of the NSAID, an alternative non-NSAID analgesic, or the nonacetylated salicylates should be used. If that is impossible and a nonsalicylate NSAID is required in the high-risk patient, one should treat concomitantly with tolerable doses of misoprostol and prescribe that the NSAID be taken with food. If the patient is intolerant of misoprostol, H2 antagonists or omeprazole should be considered to decrease the risk of developing an NSAID-induced duodenal ulcer. If patients are not in the defined high-risk groups, given the present costs of H2 antagonists, omeprazole, and misoprostol, there seems to be little justification in treating the patient prophylactically. However, if the patient develops progressive iron-deficiency anemia or occult fecal blood loss not due to an obvious malignancy, endoscopy can be recommended to determine the cause. If there is evidence of a significant NSAID-induced gastric or duodenal ulcer, the NSAID should be stopped and the ulcer treated. If that is impossible, the NSAID dosage should be as low as possible, and the ulcer treated. If an ulcer is found, either a biopsy for H. pylori or a serum assay for the organism should be obtained. Once the ulcer is healed through appropriate therapy, and if NSAIDs are still to be used, prophylaxis with misoprostol should be considered.(ABSTRACT TRUNCATED AT 250 WORDS)

Beta 2 (CD18) mutations abolish ligand recognition by I domain integrins LFA-1 (alpha L beta 2, CD11a/CD18) and MAC-1 (alpha M beta 2, CD11b/CD18)

The "I" domains of the beta 2 (CD18) leukocyte integrins are implicated in ligand binding function. Moreover, rather than recognizing linear peptide sequences, this class of integrins generally recognizes multiple discontinuous sites on immunoglobulin superfamily adhesion receptors. A conserved cluster of oxygenated residues is involved in ligand recognition by beta 1 and beta 3 integrins. In the present study, we evaluated the role of this region in the I domain-containing beta 2 integrins. Recombinant alpha L beta 2 (LFA-1, CD11a/CD18) and alpha M beta 2 (MAC-1, CD11b/CD18) were expressed on COS cells, and function was assessed by adhesion to ICAM-1 or iC3b, respectively. Alanine substitution at position Asp134 or Ser136 in beta 2 produced a complete loss in the capacity of both alpha L beta 2 and alpha M beta 2 to support cell adhesion. In contrast, substitution at Asp128 or Ser138 resulted in loss of beta 2 surface expression when co-transfected with alpha L (CD11a) or alpha M (CD11b). These data provide the first evidence for involvement of the beta 2 subunit in ligand binding to I domain integrins.

Retroreflecting ellipsometer for measuring the birefringence of optical disk substrates

A retroreflecting ellipsometer has been constructed for measuring the birefringence of optical disk substrates. In contrast to conventional ellipsometers with two mechanical arms, this system has only one arm along which both the incident and reflected beams travel. This construction eliminates the mechanical limitations of conventional ellipsometers, thereby permitting normal incidence on the sample. In addition, the single arm is adjustable in two dimensions, with the polar incident angle, θ(inc), varying from 0° to 70°, and the azimuthal incident angle, Φ(inc), varying from 0° to 360°. The condition of normal incidence permits accurate measurement of in-plane birefringence. The adjustability of both θ(inc) and Φ(inc) is necessary for the measurement of possible tilts of the index ellipsoid, and also for the variation of birefringence through the substrate thickness. Measurement results showing the useful features of the equipment are presented. The optics of the hemispherical assembly used for retroreflection as well as for the elimination of undesirable refractions are also studied by use of the ZEMAX lens design program.

Transcultural nursing. A personal and professional challenge

The traveling nurse is a guest in the host country. It is wise to remember that we represent our country and our culture--we are the only Americans many of the locals have even seen. Be sure that foreigners see in us the very best example of American citizens. After work, there is often opportunity to spend time with the local people. They are usually extremely hospitable and anxious to share their culture. A nurse who can get involved with the local people has the chance to learn so much--different values, priorities, and customs. The culture may be rich in history and folklore. Their approach to health care can be fascinating--very different from our own, yet effective in many ways. There are often highly skilled craftsmen among the people are, producing wonderfully sophisticated things from nearly nothing. It is a source of real joy to bring back treasures from a culture one has come to know. In addition to the opportunity for clinical growth and the refinement of team skills, foreign travel provides an opportunity to grow personally. Adapting to new and more primitive surroundings requires patience and understanding. Interacting with people of a different culture also gives one the opportunity to evaluate ones own beliefs and attitudes. Sometimes it is surprising to realize that we are more snobbish or prejudiced than we believed; that revelation can be an opportunity for growth and change and a new source of pride in our country, our profession, and ourselves.