1,051 research outputs found
How strange are compact star interiors ?
We discuss a Nambu--Jona-Lasinio (NJL) type quantum field theoretical
approach to the quark matter equation of state with color superconductivity and
construct hybrid star models on this basis. It has recently been demonstrated
that with increasing baryon density, the different quark flavors may occur
sequentially, starting with down-quarks only, before the second light quark
flavor and at highest densities also the strange quark flavor appears. We find
that color superconducting phases are favorable over non-superconducting ones
which entails consequences for thermodynamic and transport properties of hybrid
star matter. In particular, for NJL-type models no strange quark matter phases
can occur in compact star interiors due to mechanical instability against
gravitational collapse, unless a sufficiently strong flavor mixing as provided
by the Kobayashi-Maskawa-'t Hooft determinant interaction is present in the
model. We discuss observational data on mass-radius relationships of compact
stars which can put constraints on the properties of dense matter equation of
state.Comment: 7 pages, 2 figures, to appear in the Proceedings of the International
Conference SQM2009, Buzios, Rio de Janeiro, Brazil, Sep.27-Oct.2, 200
Rooting Cuttings of Northern Red Oak (Quercus rubra L.)
Several techniques have been used experimentally to vegetatively propagate northern red oak (Quercus rubra L.), including: 1) rooting juvenile softwood cuttings in intermittent mist, 2) rooting shoots originating from mature buds grafted onto juvenile root stocks, and 3) in vitro shoot proliferation of juvenile or mature shoots followed by in vitro rooting. Of these techniques, rooting juvenile softwood cuttings has provided the most consistent results for northern red oak (NRO). Juvenility (or at least the associated ability to form adventitious roots) disappears rapidly among progressive flushes of growth in NRO seedlings. Decreased rooting has been reported for NRO shoots obtained from progressive flushes of growth produced within a growing season, as well as shoots representing flushes obtained from successive seasons of growth. However, as with many other tree species, the process of maturation in NRO can be slowed by pruning to encourage juvenile shoot production. Optimizing the number of juvenile cuttings produced from each stock plant is necessary for efficient rooted cutting production systems. In addition, rooting conditions must be determined for the shoots produced under these pruning regimes. Two NRO rooted cutting studies are currently being conducted at NCSU. The objective of the first study is to evaluate the effects of stock plant pruning location, diameter, and age on new shoot production. Treatments include pruning first-year seedlings, as well as one-, two-, and three-year-old seedlings to the base of the first, second, third, or fourth flush of growth produced during the first growing season. The objective of the second study is to evaluate the ability of the shoots produced in the first study to form adventitious roots. Treatments include three rooting hormone levels (0.5%, 1%, and 1.5% IBA) and a control (45% EtOH). Preliminary results from both studies will be presented.Papers and abstracts from the 27th Southern Forest Tree Improvement Conference held at Oklahoma State University in Stillwater, Oklahoma on June 24-27, 2003
Monomorphic post-transplant lymphoproliferative disorder of the tongue: case report and review of literature
<p>Abstract</p> <p>Background</p> <p>Post-transplant lymphoproliferative disorder (PTLD) is a spectrum of hematological diseases arising in context of immunosuppression after organ transplantation. PTLD can involve any organ; however, it is extremely rare in oral cavity.</p> <p>Methods</p> <p>Using morphologic and immunophenotypic approaches we have studied a case of monomorphic PTLD of the tongue that developed in a patient following unilateral kidney and pancreas transplantation on immunosuppressive therapy. Additionally, cases of PTLD in the oral cavity were reviewed in the English literature.</p> <p>Results</p> <p>The neoplasm showed large cell morphology and B-cell phenotype. In situ hybridization for Epstein-Barr virus was positive. Complete remission was obtained after decreasing immunosuppressive therapy. The patient remained in remission at 790 days' follow up.</p> <p>Conclusion</p> <p>This rare case increased our awareness of PTLD in the oral cavity of patients following solid organ transplantation and immunosuppressive therapy.</p
Association of acute myeloid leukemias most immature phenotype with risk groups and outcomes
The precise phenotype and biology of acute myeloid leukemia stem cells remain controversial, in part because the âgold standardâ immunodeficient mouse engraftment assay fails in a significant fraction of patients and identifies multiple cell-types in others. We sought to analyze the clinical utility of a novel assay for putative leukemia stem cells in a large prospective cohort. The leukemic cloneâs most primitive hematopoietic cellular phenotype was prospectively identified in 109 newly-diagnosed acute myeloid leukemia patients, and analyzed against clinical risk groups and outcomes. Most (80/109) patients harbored CD34+CD38â leukemia cells. The CD34+CD38â leukemia cells in 47 of the 80 patients displayed intermediate aldehyde dehydrogenase expression, while normal CD34+CD38â hematopoietic stem cells expressed high levels of aldehyde dehydrogenase. In the other 33/80 patients, the CD34+CD38â leukemia cells exhibited high aldehyde dehydrogenase activity, and most (28/33, 85%) harbored poor-risk cytogenetics or FMS-like tyrosine kinase 3 internal tandem translocations. No CD34+ leukemia cells could be detected in 28/109 patients, including 14/21 patients with nucleophosmin-1 mutations and 6/7 acute promyelocytic leukemia patients. The patients with CD34+CD38â leukemia cells with high aldehyde dehydrogenase activity manifested a significantly lower complete remission rate, as well as poorer event-free and overall survivals. The leukemic cloneâs most immature phenotype was heterogeneous with respect to CD34, CD38, and ALDH expression, but correlated with acute myeloid leukemia risk groups and outcomes. The strong clinical correlations suggest that the most immature phenotype detectable in the leukemia might serve as a biomarker for âclinically-relevantâ leukemia stem cells. ClinicalTrials.gov: {"type":"clinical-trial","attrs":{"text":"NCT01349972","term_id":"NCT01349972"}}NCT01349972
Modern compact star observations and the quark matter equation of state
We present a hybrid equation of state (EoS) for dense matter that satisfies
phenomenological constraints from modern compact star (CS) observations which
indicate high maximum masses (M = 2 M_sun) and large radii (R> 12 km). The
corresponding isospin symmetric EoS is consistent with flow data analyses of
heavy-ion collisions and a deconfinement transition at approx. 0.55 fm^{-3}.
The quark matter phase is described by a 3-flavor Nambu--Jona-Lasinio model
that accounts for scalar diquark condensation and vector meson interactions
while the nuclear matter phase is obtained within the
Dirac-Brueckner-Hartree-Fock (DBHF) approach using the Bonn-A potential. We
demonstrate that both pure neutron stars and neutron stars with quark matter
cores (QCSs) are consistent with modern CS observations. Hybrid star
configurations with a CFL quark core are unstable.Comment: 16 pages, 4 figures; published version, important note added in proo
Randomized multicenter phase II study of flavopiridol (alvocidib), cytarabine, and mitoxantrone (FLAM) versus cytarabine/daunorubicin (7+3) in newly diagnosed acute myeloid leukemia
Serial studies have demonstrated that induction therapy with FLAM [flavopiridol (alvocidib) 50 mg/m2 days 1â3, cytarabine 667 mg/m2/day continuous infusion days 6â8, and mitoxantrone (FLAM) 40 mg/m2 day 9] yields complete remission rates of nearly 70% in newly diagnosed poor-risk acute myeloid leukemia. Between May 2011âJuly 2013, 165 newly diagnosed acute myeloid leukemia patients (age 18â70 years) with intermediate/adverse-risk cytogenetics were randomized 2:1 to receive FLAM or 7+3 (cytarabine 100 mg/m2/day continuous infusion days 1â7 and daunorubicin 90 mg/m2 days 1â3), across 10 institutions. Some patients on 7+3 with residual leukemia on day 14 received 5+2 (cytarabine 100 mg/m2/day continuous infusion days 1â5 and daunorubicin 45 mg/m2 days 1â2), whereas patients on FLAM were not re-treated based on day 14 bone marrow findings. The primary objective was to compare complete remission rates between one cycle of FLAM and one cycle of 7+3. Secondary end points included safety, overall survival and event-free survival. FLAM led to higher complete remission rates than 7+3 alone (70% vs. 46%; P=0.003) without an increase in toxicity, and this improvement persisted after 7+3+/â5+2 (70% vs. 57%; P=0.08). There were no significant differences in overall survival and event-free survival in both arms but post-induction strategies were not standardized. These results substantiate the efficacy of FLAM induction in newly diagnosed AML. A phase III study is currently in development. This study is registered with clinicaltrials.gov identifier: 01349972
Engineering pyruvate decarboxylase-mediated ethanol production in the thermophilic host Geobacillus thermoglucosidasius
This study reports the expression, purification, and kinetic characterization of a pyruvate decarboxylase (PDC) from Gluconobacter oxydans . Kinetic analyses showed the enzyme to have high affinity for pyruvate (120 ÎŒM at pH 5), high catalytic efficiency (4.75Ă105 Mâ1 sâ1 at pH 5), a pHopt of approximately 4.5 and an in vitro temperature optimum at approximately 55 °C. Due to in vitro thermostablity (approximately 40 % enzyme activity retained after 30 min at 65 °C), this PDC was considered to be a suitable candidate for heterologous expression in the thermophile Geobacillus thermoglucosidasius for ethanol production. Initial studies using a variety of methods failed to detect activity at any growth temperature (45â55 °C). However, the application of codon harmonization (i.e., mimicry of the heterogeneous hostâs transcription and translational rhythm) yielded a protein that was fully functional in the thermophilic strain at 45 °C (as determined by enzyme activity, Western blot, mRNA detection, and ethanol productivity). Here, we describe the first successful expression of PDC in a true thermophile. Yields as high as 0.35±0.04 g/g ethanol per gram of glucose consumed were detected, highly competitive to those reported in ethanologenic thermophilic mutants. Although activities could not be detected at temperatures approaching the growth optimum for the strain, this study highlights the possibility that previously unsuccessful expression of pdcs in Geobacillus spp. may be the result of ineffective transcription/translation coupling.Web of Scienc
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