3,163 research outputs found
Model for hypernucleus production in heavy ion collisions
We estimate the production cross sections of hypernuclei in projectile like
fragment (PLF) in heavy ion collisions. The discussed scenario for the
formation cross section of hypernucleus is: (a) Lambda particles are produced
in the participant region but have a considerable rapidity spread and (b)
Lambda with rapidity close to that of the PLF and total momentum (in the rest
system of PLF) up to Fermi motion can then be trapped and produce hypernuclei.
The process (a) is considered here within Heavy Ion Jet Interacting Generator
HIJING-BBbar model and the process (b) in the canonical thermodynamic model
(CTM). We estimate the production cross-sections for light hypernuclei for C +
C at 3.7 GeV total nucleon-nucleon center of mass energy and for Ne+Ne and
Ar+Ar collisions at 5.0 GeV. By taking into account explicitly the impact
parameter dependence of the colliding systems, it is found that the cross
section is different from that predicted by the coalescence model and large
discrepancy is obtained for 6_He and 9_Be hypernuclei.Comment: 9 pages, 4 figures, 3 tables, revtex4, added reference
N-glycans of human amniotic fluid transferrin stimulate progesterone production in human first trimester trophoblast cells in vitro
Aims: During pregnancy, the placenta produces a variety of steroid hormones and proteins. Several of these substances have been shown to exert immunomodulatory effects. Progesterone is thought to mediate some of these effects by regulating uterine responsiveness. The aim of this study was to clarify the effect of amniotic fluid transferrin and its N-glycans on the release of progesterone by first trimester trophoblast cells in vitro. Methods: Cytotrophoblast cells were prepared from human first trimester placentae by trypsin-DNAse dispersion of villous tissue followed by a percoll gradient centrifugation and depletion of CD45 positive cells by magnetic cell sorting. Trophoblasts were incubated with varying concentrations (50-300 mug/ml) of transferrin from human amniotic fluid and serum as well as with N-glycans obtained from amniotic fluid transferrin. Culture supernatants were assayed for progesterone by enzyme-immunometric methods. Results: The release of progesterone increased in amniotic fluid transferrin- and N-glycan-treated trophoblast cell cultures compared to untreated trophoblast cells. There was no stimulating effect of serum transferrin on the progesterone production of trophoblast cells. Conclusions: The results suggest that amnion-transferrin and especially its N-glycans modulate the endocrine function of trophoblasts in culture by up regulating progesterone secretion
The effects of meson mixing on dilepton spectra
The effect of scalar and vector meson mixing on the dilepton radiation from
hot and dense hadronic matter is estimated in different isospin channels. In
particular, we study the effect of - and mixing and
calculate the corresponding rates. Effects are found to be significant compared
to standard - and - annihilations. While the mixing in
the isoscalar channel mostly gives a contribution in the invariant mass range
between the two-pion threshold and the peak, the isovector channel
mixing induces an additional peak just below that of the .
Experimentally, the dilepton signals from - mixing seem to be more
tractable than those from - mixing.Comment: 10 pages, 9 figure
Nurse practice environments and outcomes: Implications for oncology nursing
PURPOSE/OBJECTIVES:
To examine practice environments and outcomes of nurses working in oncology units or Magnet hospitals and to understand the association between the two.
DESIGN:
Secondary analysis of survey data collected in 1998.
SETTING:
Medical and surgical units of 22 hospitals, of which 7 were recognized by the American Nurses Credentialing Center Magnet program.
SAMPLE:
1,956 RNs, of whom 305 worked in oncology units.
METHODS:
Chi-square tests compared nurse-reported outcomes by work setting, analysis of variance tested practice environment differences by setting, and logistic regression estimated the effects of practice environment, specialty, and Magnet status on outcomes.
MAIN RESEARCH VARIABLES:
Practice environments, emotional exhaustion, job satisfaction, and quality of care.
FINDINGS:
Oncology nurses had superior outcomes compared with nononcology nurses. Emotional exhaustion was significantly lower among oncology nurses working in Magnet hospitals. Scores on the Collegial Nurse-Physician Relations subscale were highest among oncology nurses. Outcomes were associated with Practice Environment Scale of the Nursing Work Index scores and Magnet status. Oncology nurses with favorable collegial nurse-physician relations were twice as likely to report high-quality care.
CONCLUSIONS:
Oncology nurses benefit from working in American Nurses Credentialing Center Magnet hospitals. Adequate staffing and resources are necessary to achieve optimal outcomes. Collegial nurse-physician relations appear to be vital to optimal oncology practice settings.
IMPLICATIONS FOR NURSING:
In addition to pursuing American Nurses Credentialing Center Magnet recognition, nurse managers should assess practice environments and target related interventions to improve job satisfaction and retention. High-priority areas for interventions include ensuring adequate staff and resources, promoting nurse-physician collaboration, and strengthening unit-based leadership.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94160/1/Nurse practice environments and outcomes Implications for oncology nursing.pd
Disparities in breast cancer care delivery: Solving a complex puzzle
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94110/1/Disparities in breast cancer care delivery Solving a complex puzzle.pd
Theory of Optical Tweezers
We derive a partial-wave (Mie) expansion of the axial force exerted on a
transparent sphere by a laser beam focused through a high numerical aperture
objective. The results hold throughout the range of interest for practical
applications. The ray optics limit is shown to follow from the Mie expansion by
size averaging. Numerical plots show large deviations from ray optics near the
focal region and oscillatory behavior (explained in terms of a simple
interferometer picture) of the force as a function of the size parameter.
Available experimental data favor the present model over previous ones.Comment: 4 pages, 3 figure
Multi-stage emplacement of the Götemar Pluton, SE Sweden: new evidence inferred from field observations and microfabric analysis, including cathodoluminescence microscopy
The emplacement of the Mesoproterozoic Götemar Pluton into Paleoproterozoic granitoid host rocks of the Transscandinavian Igneous Belt is re-examined by microfabric analysis, including cathodoluminescence microscopy. Field data on the pluton-host rock system are used to strengthen the model. The Götemar Pluton, situated on the Baltic Shield of SE Sweden, is a horizontally zoned tabular structure that was constructed by the intrusion of successive pulses of magma with different crystal/melt ratios, at an estimated crustal depth of 4–8 km. Initial pluton formation involved magma ascent along a vertical dike, which was arrested at a mechanical discontinuity within the granitoid host rocks; this led to the formation of an initial sill. Subsequent sill stacking and their constant inflation resulted in deformation and reheating of existing magma bodies, which also raised the pluton roof. This multi-stage emplacement scenario is indicated by complex dike relationships and the occurrence of several generations of quartz (Si-metasomatism). The sills were charged by different domains of a heterogeneous magma chamber with varying crystal/melt ratios. Ascent or emplacement of magma with a high crystal/melt ratio is indicated by syn-magmatic deformation of phenocrysts. Complex crystallization fabrics (e.g. oscillatory growth zoning caused by high crystal defect density, overgrowth and replacement features, resorbed and corroded crystal cores, rapakivi structure) are mostly related to processes within the main chamber, that is repeated magma mixing or water influx
Conducting rigorous research with subgroups of at-risk youth: lessons learned from a teen pregnancy prevention project in Alaska
In 2010, Alaska Department of Health and Social Services (DHSS) received federal funding to test an
evidence-based teen pregnancy prevention program. The grant required a major modification to an existing
program and a randomized control trial (RCT) to test its effectiveness. As the major modifications, Alaska
used peer educators instead of adults to deliver the program to youth aged 1419 instead of the original
curriculum intended age range of 1214. Cultural and approach adaptations were included as well. After
4 years of implementation and data collection, the sample was too small to provide statistically significant
results. The lack of findings gave no information about the modification, nor any explanation of how the
curriculum was received, or reasons for the small sample. This paper reports on a case study follow-up to
the RCT to better understand outcome and implementation results. For this study, researchers reviewed
project documents and interviewed peer educators, state and local staff, and evaluators. Three themes
emerged from the data: (a) the professional growth of peer educators and development of peer education, (b)
difficulties resulting from curriculum content, especially for subpopulations of sexually active youth, youth
identified as lesbian, gay, bisexual, transgender, queer, intersex and/or asexual, pregnant, and parenting
youth and (c) the appropriateness of an RCT with subpopulations of at-risk youth. Three recommendations
emerged from the case study. First, including as many stakeholders as possible in the program and
evaluation design phases is essential, and must be supported by appropriate funding streams and training.
Second, there must be recognition of the multiple small subpopulations found in Alaska when adapting
programs designed for a larger and more homogeneous population. Third, RCTs may not be appropriate
for all population subgroups.Ye
Detection of Circulating Tumour Cells from Blood of Breast Cancer Patients via RT-qPCR
Breast cancer is still the most frequent cause of cancer-related death in women worldwide. Often death is not caused only by the primary tumour itself, but also by metastatic lesions. Today it is largely accepted, that these remote metastases arise out of cells, which detach from the primary tumour, enter circulation, settle down at secondary sites in the body and are called Circulating Tumour Cells (CTCs). The occurrence of such minimal residual diseases in the blood of breast cancer patients is mostly linked to a worse prognosis for therapy outcome and overall survival. Due to their very low frequency, the detection of CTCs is, still a technical challenge. RT-qPCR as a highly sensitive method could be an approach for CTC-detection from peripheral blood of breast cancer patients. This assumption is based on the fact that CTCs are of epithelial origin and therefore express a different gene panel than surrounding blood cells. For the technical approach it is necessary to identify appropriate marker genes and to correlate their gene expression levels to the number of tumour cells within a sample in an in vitro approach. After that, samples from adjuvant and metastatic patients can be analysed. This approach may lead to new concepts in diagnosis and treatmen
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