2,114 research outputs found
Identification of the slow E3 transition 136mCs -> 136Cs with conversion electrons
We performed at ISOLDE the spectroscopy of the decay of the 8- isomer in
136Cs by and conversion-electron detection. For the first time the excitation
energy of the isomer and the multipolarity of its decay have been measured. The
half-life of the isomeric state was remeasured to T1/2 = 17.5(2) s. This isomer
decays via a very slow 518 keV E3 transition to the ground state. In addition
to this, a much weaker decay branch via a 413 keV M4 and a subsequent 105 keV
E2 transition has been found. Thus we have found a new level at 105 keV with
spin 4+ between the isomeric and the ground state. The results are discussed in
comparison to shell model calculations.Comment: Phys. Rev. C accepted for publicatio
Three Questions on Lorentz Violation
We review the basics of the two most widely used approaches to Lorentz
violation - the Stardard Model Extension and Noncommutative Field Theory - and
discuss in some detail the example of the modified spectrum of the synchrotron
radiation. Motivated by touching upon such a fundamental issue as Lorentz
symmetry, we ask three questions: What is behind the search for Lorentz
violation? Is String Theory a physical theory? Is there an alternative to
Supersymmetry?Comment: 16 pages; invited luecture at DICE2006 - Piombino, Italy - September
200
General Relativistic versus Newtonian: a universality in radiation hydrodynamics
We compare Newtonian and general relativistic descriptions of the stationary
accretion of self-gravitating fluids onto compact bodies. Spherical symmetry
and thin gas approximation are assumed. Luminosity depends, amongst other
factors, on the temperature and the contribution of gas to the total mass, in
both -- general relativistic () and Newtonian () -- models. We
discover a remarkable universal behaviour for transonic flows: the ratio of
respective luminosities is independent of the fractional mass of
the gas and depends on asymptotic temperature. It is close to 1 in the regime
of low asymptotic temperatures and can grow by one order of magnitude for high
temperatures. These conclusions are valid for a wide range of polytropic
equations of state.Comment: 8 pages, 4 figure
Absorbed radiation dosimetry of the D3-specific PET radioligand [18F]FluorTriopride estimated using rodent and nonhuman primate
[(18)F]FluorTriopride ([(18)F]FTP) is a dopamine D(3)-receptor preferring radioligand with potential for investigation of neuropsychiatric disorders including Parkinson disease, dystonia and schizophrenia. Here we estimate human radiation dosimetry for [(18)F]FTP based on the ex-vivo biodistribution in rodents and in vivo distribution in nonhuman primates. Biodistribution data were generated using male and female Sprague-Dawley rats injected with ~370 KBq of [(18)F]FTP and euthanized at 5, 30, 60, 120, and 240 min. Organs of interest were dissected, weighed and assayed for radioactivity content. PET imaging studies were performed in two male and one female macaque fascicularis administered 143-190 MBq of [(18)F]FTP and scanned whole-body in sequential sections. Organ residence times were calculated based on organ time activity curves (TAC) created from regions of Interest. OLINDA/EXM 1.1 was used to estimate human radiation dosimetry based on scaled organ residence times. In the rodent, the highest absorbed radiation dose was the upper large intestines (0.32-0.49 mGy/MBq), with an effective dose of 0.07 mSv/MBq in males and 0.1 mSv/MBq in females. For the nonhuman primate, however, the gallbladder wall was the critical organ (1.81 mGy/MBq), and the effective dose was 0.02 mSv/MBq. The species discrepancy in dosimetry estimates for [(18)F]FTP based on rat and primate data can be attributed to the slower transit of tracer through the hepatobiliary track of the primate compared to the rat, which lacks a gallbladder. Out findings demonstrate that the nonhuman primate model is more appropriate model for estimating human absorbed radiation dosimetry when hepatobiliary excretion plays a major role in radiotracer elimination
Variable rest masses in 5-dimensional gravitation confronted with experimental data
Cosmological solutions of Einstein equation for a \mbox{5-dimensional}
space-time, in the case of a dust-filled universe, are presented. With these
solutions we are able to test a hypothetical relation between the rest mass of
a particle and the dimension. Comparison with experiment strongly
refutes the implied dependence of the rest mass on the cosmological time.Comment: Some references adde
Transplantation of a Human Mammary Carcinoma Cell Line (BT 20) Into Nude Mice
Cell suspensions of a human mammary carcinoma cell line (BT 20), when injected subcutaneously into nude athymic mice (BALB/c Nu/Nu), produced tumor nodules at the injection site. Subsequent serial transplantations also gave rise to neoplastic nodules after latency periods averaging 3 weeks. The nodules displayed morphologic and functional characteristics comparable to those of the original tumor cells. Metastases, however, were not observed in any of the tumor-bearing mic
Selective up-regulation of NMDA-NR1 receptor expression in myenteric plexus after TNBS induced colitis in rats
BACKGROUND: N-methyl-D-aspartic acid (NMDA) spinal cord receptors play an important role in the development of hyperalgesia following inflammation. It is unclear, however, if changes in NMDA subunit receptor gene expression in the colonic myenteric plexus are associated with colonic inflammation. We investigated regulation of NMDA-NR1 receptor gene expression in TNBS induced colitis in rats. Male Sprague-Dawley rats (150 g–250 g) were treated with 20 mg trinitrobenzene sulfonic acid (TNBS) diluted in 50% ethanol. The agents were delivered with a 24 gauge catheter inserted into the lumen of the colon. The animals were sacrificed at 2, 7, 14, 21, and 28 days after induction of the colitis, their descending colon was retrieved for reverse transcription-polymerase chain reaction; a subset of animals' distal colon was used for two-dimensional (2-D) western analysis and immunocytochemistry. RESULTS: NR1-exon 5 (N1) and NR1-exon 21 (C1) appeared 14, 21 and 28 days after TNBS treatment. NR1 pan mRNA was up-regulated at 14, 21, and 28 days. The NR1-exon 22 (C2) mRNA did not show significant changes. Using 2-D western analysis, untreated control rats were found to express only NR1(001 )whereas TNBS treated rats expressed NR1(001), NR1(011, )and NR1(111). Immunocytochemistry demonstrated NR1-N1 and NR1-C1 to be present in the myenteric plexus of TNBS treated rats. CONCLUSION: These results suggest a role for colonic myenteric plexus NMDA receptors in the development of neuronal plasticity and visceral hypersensitivity in the colon. Up-regulation of NMDA receptor subunits may reflect part of the basis for chronic visceral hypersensitivity in conditions such as post-infectious irritable bowel syndrome
Transformed Minds
In this brief collection of essays, professors who teach in the Department of History and Government at Cedarville University explore the biblical foundation for the academic disciplines unique to their Department. The Excerpt (above) contains the full text of the book.https://digitalcommons.cedarville.edu/faculty_books/1182/thumbnail.jp
Anti-Mullerian-Hormone during pregnancy and peripartum using the new Beckman Coulter AMH Gen II Assay
Background: AMH levels determined by the conventional AMH assay declined during pregnancy and postpartum. A new Beckman Coulter AMH Gen II assay removes the potentially assay-interfering complement which is activated in pregnancy. The aim of this study was to evaluate if the decline of AMH levels in the serum of pregnant women during the course of pregnancy and peripartum was assay-dependent and thus artificial. Methods: In this cross-sectional study prepartal blood samples were collected from 62 patients (median age 30.6 years [interquartile range: 25.6 - 34.5]) in the third trimester of pregnancy and again 1–4 days after delivery between 2011 and 2012. In another cohort of 11 patients (median age 34.1 years [interquartile range: 32.6 - 37.8]) blood samples were taken in different trimesters of pregnancy between 1995 and 2001. The conventional and the modified AMH assay were performed in the same patient serum samples. We used the conventional and the modified AMH-Gen-II ELISA (Beckman Coulter, Immunotech, Webster, USA) for the assessment of AMH levels. The Wilcoxon signed rank test was used for determining differences between AMH levels pre- and postpartum. The method of Bland and Altman was applied for analyzing the agreement of both methods for determining AMH levels. Results: AMH values peripartum were lower than those expected in fertile non-pregnant women of comparable age. An overall mean difference of 0.44 ng/ml was observed between the conventional and the modified assay. Measurements with the modified assay showed a significant decline of postpartal levels compared with prepartal levels which is consistent with values obtained using the conventional assay (both p < 0.00001). Compared to the longitudinal measurements of AMH levels determined using the conventional assay, AMH levels obtained using the modified assay suggest a steeper decline of values during the course of pregnancy. Conclusion: By comparing the conventional assay for AMH determination with the modified assay the present study confirmed that AMH levels decline during the course of pregnancy and early after delivery
Is it possible to formulate least action principle for dissipative systems?
A longstanding open question in classical mechanics is to formulate the least
action principle for dissipative systems. In this work, we give a general
formulation of this principle by considering a whole conservative system
including the damped moving body and its environment receiving the dissipated
energy. This composite system has the conservative Hamiltonian
where is the kinetic energy of the moving body, its potential
energy and the energy of the environment. The Lagrangian can be derived
by using the usual Legendre transformation where is the
total kinetic energy of the environment. An equivalent expression of this
Lagrangian is where is the energy dissipated by the
friction from the moving body into the environment from the beginning of the
motion. The usual variation calculus of least action leads to the correct
equation of the damped motion. We also show that this general formulation is a
natural consequence of the virtual work principle.Comment: 11 pages, no figur
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