The role of seed electrons on the plasma breakdown and preglow of electron cyclotron resonance ion source.

The 14 GHz Electron Cyclotron Resonance Ion Source at University of Jyväskylä, Department of Physics (JYFL) has been operated in pulsed mode in order to study the plasma breakdown and preglow effect. It was observed that the plasma breakdown time and preglow characteristics are affected by seed electrons provided by a continuous low power microwave signal at secondary frequency. Sustaining low density plasma during the off-period of high power microwave pulses at the primary frequency shifts the charge state distribution of the preglow transient toward higher charge states. This could be exploited for applications requiring fast and efficient ionization of radioactive elements as proposed for the Beta Beam project within the EURISOL design study, for example. In this article we present results measured with helium and neon.

The effect of rf pulse pattern on bremsstrahlung and ion current time evolution of an ECRIS.

Time-resolved helium ion production and bremsstrahlung emission from JYFL 14 GHz ECRIS is presented with different radio frequency pulse lengths. rf on times are varied from 5 to 50 ms and rf off times from 10 to 1000 ms between different measurement sets. It is observed that the plasma breakdown occurs a few milliseconds after launching the rf power into the plasma chamber, and in the beginning of the rf pulses a preglow transient is seen. During this transient the ion beam currents are increased by several factors compared to a steady state situation. By adjusting the rf pulse separation the maximum ion beam currents can be maintained during the so-called preglow regime while the amount of bremsstrahlung radiation is significantly decreased.

Measurement of radial and axial high energy x-ray spectra in electron cyclotron resonance ion source plasmas.

Radial and axial x-ray measurements of electron cyclotron resonance ion sources operating at microwave frequencies of 6.4 and 14 GHz are presented. Results indicate a greater detected photon energy in the radial direction than the axial direction for both the 6.4 GHz source and the 14 GHz source. It is also seen that the 14 GHz source produces x-rays with higher energies, when compared to the 6.4 GHz source, in both radial and axial directions.

Determination of systolic blood pressure via pulse oximeter in transported pediatric patients.

OBJECTIVE: To compare pulse oximetry waveform systolic blood pressure measurements (POWSBP) to measurements obtained by noninvasive blood pressure measurement (NIBPM) during the transport of children. DESIGN: A prospective, convenience sample. SETTING AND PARTICIPANTS: All patients transported by a dedicated Pediatric Critical Care Transport Team were eligible for inclusion. Senior transport nurses with over 3 years of transport experience who had been instructed by the principal investigator (PI) in the technique, obtained the measurements and recorded the results. A convenience sample was obtained based on the presence or absence of one of the senior nurses on the transport team. METHODS: Measurements of blood pressure were obtained by POWSBP and NIBPM (PROPAQ@; Protocol Systems, Beaverton, OR) on pediatric patients during transport in moving ambulances or fixed wing aircraft. Measurement of systolic blood pressure by pulse oximetry (POWSBP) was obtained on all patients by observing the return of the plethysmographic waveform of the pulse oximeter as the blood pressure cuff deflated. The patients were divided into two groups; in group A POWSBP measurements were obtained by using the automated BP cuff from the PROPAQ@ and in group B by a manual BP cuff. These measurements were compared to NIBPM readings obtained at the same time. Between 3 and 13 paired readings were obtained for each patient. The actual transport time determined the number of measurements obtained. RESULTS: A total of 24 patients were enrolled in the study. Multiple matched pair readings (both POWSBP and NIBPM) were obtained from each patient for a total of 180 data points. A two variable linear regression model was run which identified a significant correlation between POWSBP and NIBPM. Group A, r = 0.7592 and r = 0.9477 for group B significant at P< 0.000001. Further, a corrective equation was developed for use with an automated BP cuff. CONCLUSIONS: The use of pulse oximetry waveform systolic blood pressure measurement is a quick and easy method with which to obtain systolic blood pressure in children during transport and shows a close correlation to the standard noninvasive blood pressure measurement. If an automated blood pressure cuff is used, then a corrective equation [NIBP-S = 41.686 + 0.7377(POBPS)] is required. Further validation in a larger group of patients is recommended.

Intact and impaired conceptual memory processes in amnesia.

To examine the status of conceptual memory processes in amnesia, a conceptual memory task with implicit or explicit task instructions was given to amnesic and control groups. After studying a list of category exemplars, participants saw category labels and were asked to generate as many exemplars as possible (an implicit memory task) or to generate exemplars that had been in the prior study list (an explicit memory task). After incidental deep or shallow encoding of exemplars, amnesic patients showed normal implicit memory performance (priming), a normal levels-of-processing effect on priming, and impaired explicit memory performance. After intentional encoding of exemplars, amnesic patients showed impaired implicit and explicit memory performance. Results suggest that although amnesic patients can show impairments on implicit and explicit conceptual memory tasks, their deficit does not generalize to all conceptual memory tasks.

Video evaluation of pediatric trauma codes.

Video-recorded trauma resuscitations have been used to evaluate patient care and staff performance in a pediatric trauma center. Incorporated into a continuous quality improvement program, the effort has been successful in identifying patient care on a case-by-case basis that has or has not met preestablished standards. It has been used to identify noteworthy actions by the medical, nursing, and ancillary staff and to recognize any other problems that affect patient care. The program is an example of a successful continuous quality improvement program.

Normal perceptual priming of orthographically illegal nonwords in amnesia.

This study examined priming in perceptual identification of orthographically illegal nonwords in control subjects and patients with global amnesia. Subjects studied a list of orthographically illegal nonwords and then performed a perceptual identification task in which half of the stimuli were from the prior study list and half were new (unstudied) stimuli. Priming was reflected in enhanced identification accuracy of studied compared to unstudied nonwords. Amnesic patients showed significant and normal priming despite impaired recognition memory performance. Because the experimental stimuli were dissimilar to real words in terms of orthography and phonology, it is unlikely that this priming effect was mediated by activation of pre-existing representations of orthographically or phonologically similar words, morphemes, or syllables. These results demonstrate that intact perceptual priming in amnesia is not limited to stimuli that are premorbidly represented in long-term knowledge, nor to novel stimuli that conform to the rules that characterize familiar items. Further, because the experimental stimuli comprised novel letter assemblies, the results suggest that amnesic patients can show normal priming for new perceptual associations. These findings demonstrate that processes spared in amnesia can support the creation and subsequent retrieval of novel stimulus representations.

Cell type-specific activity of the N-myc promoter in human neuroblastoma cells is mediated by a downstream silencer.

The N-myc oncogene is actively transcribed in many neuroblastoma tumors, but is not expressed in mature, normal tissue of any type. Chloramphenicol acetyl transferase (CAT) assays of constructs containing N-myc sequence transfected into N-myc expressing LA-N-5 neuroblastoma cells or non-expressing HeLa carcinoma cells have revealed a 201 base pair (bp) regulatory region mediating the cell type-specific activity of the promoter. While located downstream from 5' mRNA cap sites, the region appears to function by preventing transcriptional initiation. This downstream region is capable of suppressing promoter activity independently of position, and contains an element having 100% homology with the 9 bp consensus sequence of a transcriptional silencer found in the upstream region of the lysozyme gene. DNA gel retardation assays have shown that this sequence is involved in a specific DNA-protein interaction with nuclear extract from HeLa cells that is distinct from that occurring with extract from LA-N-5 cells. These results suggest that the N-myc promoter's cell type-specific activity is regulated by a downstream silencer, and that differential binding of regulatory protein from that present in non-expressing cells may result in the constitutive N-myc expression seen in neuroblastoma.

Performance of masonry - infilled R/C frames under in - plane lateral loads : Experiments

Eleven tests were conducted on 1/2 scale, single story infilled frame specimens to study the influence of the relative strengths of the infill panels and the bounding frames and the frame aspect ratio on the performance of masonry - infilled R/C frames. It was observed that specimens with stronger infills exhibited a higter load resistance and a better energy - dissipation capability. However, their post - peak resistance dropped more rapidly as the displacement increased. In summary, infill panels tend to improve the lateral resistance of R/C frames (AU)

Reduction of endotoxin-induced vascular permeability by monoclonal antibodies against lipopolysaccharide determinants.

Endotoxin, a bacterial lipopolysaccharide implicated in the pathogenesis of septic shock, markedly alters vascular permeability following intravenous injection in rabbits. We investigated the ability of murine monoclonal antibodies to confer protection against endotoxin-induced increases in a rabbit model of ocular vascular permeability. Four monoclonal antibodies of differing specificities as well as polymyxin B were compared for their effects on endotoxin from either Escherichia coli or Pseudomonas aeruginosa. Preincubation of endotoxin with antibodies directed against Pseudomonas O side chain or core glycolipid resulted in marked attenuation of vascular permeability due to Pseudomonas endotoxin, but not E. coli endotoxin. Antilipid A antibodies were not significantly effective in neutralizing either endotoxin with in vitro preincubation. Low avidity of the antilipid A antibody, low density of lipid A binding sites, or inaccessibility of the lipid A may have prevented more marked interactions. When administered intravenously prior to endotoxin challenge, none of the antibodies demonstrated the ability to provide specific protection to subsequent endotoxin in this model. They did provide partial nonspecific protection against endotoxins regardless of epitope specificity. When administered prophylactically, polymyxin B, an antibiotic that binds to lipid A, was highly effective in neutralizing the toxic effects of endotoxin. Since antibodies to lipid A reduce mortality in septic shock, the failure to demonstrate efficacy in this study may be due to the marked sensitivity of the rabbit eye to endotoxin. Alternatively, beneficial effects from antiendotoxin antibodies in septic shock may be unrelated to the inhibition of vascular permeability. Some protection from antiendotoxin antibodies may be due to enhancement of nonspecific mechanisms.

Diethylstilbestrol di-trimethylacetate (DSTMA). A long-acting estrogen.

A series of estradiol and diethylstilbestrol (DES) esters was prepared as part of a study of the structure-activity relations in estrogens. Among the esters tested, DES di-trimethylacetate (DSTMA) exhibited the most favorable combination of a low minimum-effective dose and prolongation of effect in all experimental groups (mice, rats, dogs). Toxicity of DSTMA was low. A clinical trial in four stage III and stage IV prostatic cancer patients showed that dosage levels of DSTMA as high as 75 mg per day for short periods were well tolerated and no toxic symptoms attributable to the estrogen itself were observed.