Observation of {011} twins in Fe−Ni−C martensite using neutron powder diffraction

High resolution neutron powder diffraction measurements were performed on freshly quenched specimens of Fe-13 wt pct Ni-1.0 wt pct C martensite formed at subambient temperature and after aging for 1 hour to 293, 313, 333 and 353 K. The widths of the powder reflections in the unaged martensite indicate the presence of a large number of {011} twins in this tetragonal structure. The {011} twins were modeled as single layer randomly distributed twin faults. The model predicts powder peak breadths with the unmistakable reflection index dependence that is observed in the measured powder spectra. The magnitude of the observed peak broadening is consistent with a twin volume of 17(±4) pct. Upon aging, there is no detectable change in the number of {011} twins despite an observed decrease in the tetragonality. Previous transmission electron microscope (TEM) measurements have demonstrated the presence of these twins, but it was not clear if they formed during the martensitic transformation or upon warming from subambient temperature. This study confirms their presence immediately after transformation, indicating that they may play an important role in the transformation. B.D. B-uputler, formerly Research Assistant Materials Science Department, Northwestern University, is Postdoctoral Associate, Research School of Chemistry, Australian National University, Canberra, Australia.     

Correlations of sensory and instrumental meat tenderness values as affected by sampling techniques

A study was conducted to determine if and to what extent higher correlations between sensory meat tenderness scores and Warner-Bratzler shear measurements could be obtained by giving the sensory panelists cores rather than slices. Thirty biceps femoris roasts, from gilts representing two breeds and two lines, were cooked in preheated ovens at 160, 170 or 180°C to an internal temperature of 80°C. Roasts were held for 24 h at 4°C before sampling. Cores, both perpendicular and parallel to the direction of the muscle fibres, for the eight panelists and the instrument, as well as slices for the panelists, were sampled from each roast. Instrumental values were measured with an Instron fitted with a Warner-Bratzler shear device. Correlations were higher when cores of the same orientation were used for panelists and the Warner-Bratzler measurements. Parallel cores did as well as or better than perpendicular cores in terms of the analysis of variance and correlation values.     

Moving toward policy development on assigning publication credit for oncology nurses' contributions to scholarly and scientific work

The policy implications of a 1996 national nursing survey on the allocation of publication credit form of this paper. An earlier article (Butler & Ginn, 1997) describes and analyzes the outcome of the survey; the purpose here is to draw on that analysis, and on the relevant literature, to propose a starting place for discussion within the specialty of oncology and the nursing profession regarding assignment of credit for various contributions to collaborative scholarly work. After identifying the growing need for such a discussion and briefly highlighting the findings of the survey, the paper goes on to examine unacceptable practices in scholarly work and identify issues which should be resolved before collaborative work is undertaken. The final portion of the paper makes tentative suggestions as to principles and guidelines which might be applied to avoid disputes about the value of different contributions to a collaborative project. It is emphasized that the intention is not to advocate acceptance of the guidelines suggested here, but to create sufficient interest so that an approach to allocation of publication credit may be developed which will be consistent and relevant to the needs of the nursing profession.     

Systemic inflammatory responses to cardiopulmonary bypass: a pilot study of the effects of pentoxifylline

The potential of pentoxifylline (PTX) to modify systemic inflammatory responses and lung injury following cardiopulmonary bypass (CPB) was studied in 20 patients undergoing elective coronary artery surgery. Ten control patients were compared with ten patients who received a PTX infusion of 1 mg kg-1 h-1 during surgery. Intra-vascular pulmonary leukocyte sequestration was observed in neither group following discontinuation of CPB. Plasma elastase-alpha-1-antiprotease complex rose three-fold from baseline in both groups to peak at sternal closure. No significant plasma interleukin-1 (IL-1) response was detected. Plasma interleukin-6 (IL-6) rose in both groups from baseline to peak 4 h postoperatively. There was no correlation between plasma levels of elastase complex, IL-1 or IL-6 and impairment of postoperative oxygenation. CPB was associated with significant postoperative hypoxaemia and systemic release of neutrophil elastase and IL-6 but PTX, at the given dose, did not abrogate these responses.     

Incorporation of Transuranic Elements in Titanate Nuclear Waste Ceramics

The incorporation of actinide elements and their rare-earth element analogues in titanate nuclear waste forms is reviewed. New partitioning data are presented for three waste forms containing Purex waste simulant in combination with either NpO₂, PuO₂, or Am₂O₃. The greater proportion of transuranics partition between perovskite and zirconolite, while some americium may enter loveringite. Autoradiography revealed clusters of plutonium atoms which have been interpreted as unreacted dioxide or sesquioxide. It is concluded that the solid-state behavior of transuranic elements in titanate waste forms is poorly understood, certainly not well enough to tailor a ceramic for the incorporation of waste from reprocessing of fast breeder reactor fuel in which transuranic species are more abundant than in Purex waste.     

Effects of task- and ego-achievement goals on information seeking during task engagement.

Two studies tested the proposal that information seeking is affected by achievement goals and by stages of skill acquisition (D. N. Ruble and K. S. Frey [1991]). 188 college students worked on problems in a task- or an ego-goal condition and could request task (best solutions), objective, normative, or no information after each. As expected, task-goal Ss requested more task information mainly for later problems. Ego-goal Ss made more normative requests also for early problems, and information requests were modified by skill level. These indications that self-assessment is accompanied by self-improvement concerns under task goals and by self-enhancing concerns under ego goals have implications for the debate between self-assessment and self-evaluation theories of information seeking and for research on help seeking and feedback effects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attributions of familiarity in amnesia: Evidence from a fame judgment task.

To evaluate the extent to which amnesic patients can attribute the source of familiarity to its correct source during a fame judgment task, gains in familiarity were placed in opposition to conscious recollection. In the 1st experiment, patients and controls were told specifically that nonfamous names presented just prior to a fame judgment task were not famous; in the 2nd experiment they were told that nonfamous names were in fact famous. Although such instructions produced dramatically different results in the fame judgment performance of normal control Ss, minimal change in attribution of fame occurred for the amnesic Ss. It is concluded that the amnesic Ss were unable to attribute the familiarity of a previously presented name to its correct source because of their inability to recollect a name's prior presentation. Hence, it may be the nature of the memory query rather than the adequacy of a specific memory system that determines whether or not an amnesic patient can access information in memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Phosphorus metabolism during growth of lymphoma in mouse liver: a comparison of 31P magnetic resonance spectroscopy in vivo and in vitro

Large phosphomonoester (PME) signals are detected in the phosphorus magnetic resonance spectra (31P MRS) of many neoplastic and rapidly dividing tissues. In addition, alterations in phosphodiester (PDE) signals are sometimes seen. The present study of a murine lymphoma growing in liver showed a positive correlation between the hepatic PME/PDE ratio measured in vivo by 31P MRS at 4.7 T and the degree of lymphomatous infiltration in the liver, quantified by histology. High-resolution 31P MRS of liver extracts at 9.7 T showed that the PME peak consists largely of phosphoethanolamine (PE) and to a lesser extent of phosphocholine (PC). The concentration of both PE and PC increased positively with lymphomatous infiltration of the liver. In vivo, the PDE peak contains signals from phospholipids (mostly phosphatidylethanolamine and phosphatidylcholine) and the phospholipid breakdown products glycerophosphoethanolamine (GPE) and glycerophosphocholine (GPC). Low levels of GPE and GPC were detected in the aqueous extracts of the control and infiltrated livers; their concentrations remained unchanged as the infiltration increased. The total concentration of phospholipids measured by 31P MRS of organic extracts decreased about 3-fold as the infiltration increased to 70%. Thus, our data showed that the increased PME/PDE ratio in vivo is due to both an increase in the PME metabolites and a decrease in the PDE metabolites. We propose that this ratio can be used as a non-invasive measure of the degree of lymphomatous infiltration in vivo.     

Interactive intermediates are formed during the urea unfolding of rhodanese

Structural transitions have been studied on the pathway for urea denaturation of rhodanese. Unlike guanidinium hydrochloride, urea gives no visible precipitation. Increasing urea concentrations cause a transition in which the enzyme activity is completely lost by 4.5 M urea, and there is a shift of the intrinsic fluorescence maximum from 335 nm for the native enzyme to 350 nm. There is a maximum exposure of organized hydrophobic surfaces at 4.5 M urea as reported by the fluorescence of 1,1'-bi(4-anilino)naphthalene-5,5'-disulfonic acid. Above 4.5 M urea, this probe reports the progressive loss of organized hydrophobic surfaces. The polarization of the intrinsic fluorescence falls with increasing urea concentrations in a complex transition showing that rhodanese flexibility increases in at least two phases. Rhodanese becomes increasingly susceptible to digestion by subtilisin between 3.5 and 4.5 M urea, giving rise to large fragments. At urea concentrations > 5 M, rhodanese is completely digested. There is a small increase in the rate of sulfhydryl accessibility between 3.5 and 4.5 M urea, but there is a large increase in the sulfhydryl accessibility above 4.5 M urea. Dimethyl suberimidate cross-linking shows the presence of associated species in 3-5 M urea, but there are few cross-linkable species at lower or higher urea concentrations. These results are consistent with a model in which urea unfolding of rhodanese is associated with the initial production of a species having organized regions of structure with exposed hydrophobic surfaces separated by flexible elements.     

An outbreak of multidrug-resistant pneumococcal pneumonia and bacteremia among unvaccinated nursing home residents

BACKGROUND: Outbreaks of pneumococcal disease are uncommon and have occurred mainly in institutional settings. Epidemic, invasive, drug-resistant pneumococcal disease has not been seen among adults in the United States. In February 1996, there was an outbreak of multidrug-resistant pneumococcal pneumonia among the residents of a nursing home in rural Oklahoma. METHODS: We obtained nasopharyngeal swabs for culture from residents and employees. Streptococcus pneumoniae isolates were serotyped and compared by pulsed-field gel electrophoresis. A retrospective cohort study was conducted to identify factors associated with colonization and disease. RESULTS: Pneumonia developed in 11 of 84 residents (13 percent), 3 of whom died. Multidrug-resistant S. pneumoniae, serotype 23F, was isolated from blood and sputum from 7 of the 11 residents with pneumonia (64 percent) and from nasopharygeal specimens from 17 of the 74 residents tested (23 percent) and 2 of the 69 employees tested (3 percent). All the serotype 23F isolates were identical according to pulsed-field gel electrophoresis. Recent use of antibiotics was associated with both colonization (relative risk, 2.3; 95 percent confidence interval, 1.3 to 4.2) and disease (relative risk, 3.6; 95 percent confidence interval, 1.2 to 10.8). Only three residents (4 percent) had undergone pneumococcal vaccination. After residents received pneumococcal vaccine and prophylactic antibiotics, there were no additional cases of pneumonia, and the rates of carriage decreased substantially. CONCLUSIONS: In this outbreak a single pneumococcal strain was disseminated among the residents and employees of a nursing home. The high prevalence of colonization with a virulent organism in an unvaccinated population contributed to the high attack rate. Clusters of pneumococcal disease may be underrecognized in nursing homes, and wider use of pneumococcal vaccine is important to prevent institutional outbreaks of drug-resistant S. pneumoniae infection.