6,244 research outputs found
Exact Solutions of Model Hamiltonian Problems with Effective Interactions
We demonstrate with soluble models how to employ the effective Hamiltonian
approach of Lee and Suzuki to obtain all the exact eigenvalues of the full
Hamiltonian. We propose a new iteration scheme to obtain the effective
Hamiltonian and demonstrate its convergence properties.Comment: 12 pages and 1 figur
Interaction between graphene and SiO2 surface
With first-principles DFT calculations, the interaction between graphene and
SiO2 surface has been analyzed by constructing the different configurations
based on {\alpha}-quartz and cristobalite structures. The single layer graphene
can stay stably on SiO2 surface is explained based on the general consideration
of configuration structures of SiO2 surface. It is also found that the oxygen
defect in SiO2 surface can shift the Fermi level of graphene down which opens
out the mechanism of hole-doping effect of graphene absorbed on SiO2 surface
observed in experiments.Comment: 17 pages, 7 figure
Minimizing Effective Many-Body Interactions
A simple two-level model is developed and used to test the properties of
effective interactions for performing nuclear structure calculations in
truncated model spaces. It is shown that the effective many-body interactions
sensitively depend on the choice of the single-particle basis and they appear
to be minimized when a self- consistent Hartree-Fock basis is used.Comment: (15 pages of text and 1 postscript figure (Figure available upon
request), Preprint Number not assigned ye
Simple approximation for the starting-energy-independent two-body effective interaction with applications to 6Li
We apply the Lee-Suzuki iteration method to calculate the linked-folded
diagram series for a new Nijmegen local NN potential. We obtain an exact
starting-energy-independent effective two-body interaction for a multi-shell,
no-core, harmonic-oscillator model space. It is found that the resulting
effective-interaction matrix elements can be well approximated by the Brueckner
G-matrix elements evaluated at starting energies selected in a simple way.
These starting energies are closely related to the energies of the initial
two-particle states in the ladder diagrams. The ``exact'' and approximate
effective interactions are used to calculate the energy spectrum of 6Li in
order to test the utility of the approximate form.Comment: 15 text pages and 2 PostScript figures (available upon request).
University of Arizona preprint, Number unassigne
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Identification and characterization of dysregulated P-element induced wimpy testis-interacting RNAs in head and neck squamous cell carcinoma.
It is clear that alcohol consumption is a major risk factor in the pathogenesis of head and neck squamous cell carcinoma (HNSCC); however, the molecular mechanism underlying the pathogenesis of alcohol-associated HNSCC remains poorly understood. The aim of the present study was to identify and characterize P-element-induced wimpy testis (PIWI)-interacting RNAs (piRNAs) and PIWI proteins dysregulated in alcohol-associated HNSCC to elucidate their function in the development of this cancer. Using next generation RNA-sequencing (RNA-seq) data obtained from 40 HNSCC patients, the piRNA and PIWI protein expression of HNSCC samples was compared between alcohol drinkers and non-drinkers. A separate piRNA expression RNA-seq analysis of 18 non-smoker HNSCC patients was also conducted. To verify piRNA expression, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed on the most differentially expressed alcohol-associated piRNAs in ethanol and acetaldehyde-treated normal oral keratinocytes. The correlation between piRNA expression and patient survival was analyzed using Kaplan-Meier estimators and multivariate Cox proportional hazard models. A comparison between alcohol drinking and non-drinking HNSCC patients demonstrated that a panel of 3,223 piRNA transcripts were consistently detected and differentially expressed. RNA-seq analysis and in vitro RT-qPCR verification revealed that 4 of these piRNAs, piR-35373, piR-266308, piR-58510 and piR-38034, were significantly dysregulated between drinking and non-drinking cohorts. Of these four piRNAs, low expression of piR-58510 and piR-35373 significantly correlated with improved patient survival. Furthermore, human PIWI-like protein 4 was consistently upregulated in ethanol and acetaldehyde-treated normal oral keratinocytes. These results demonstrate that alcohol consumption may cause dysregulation of piRNA expression in HNSCC and in vitro verifications identified 4 piRNAs that may be involved in the pathogenesis of alcohol-associated HNSCC
Convergence properties of the effective interaction
The convergence properties of two perturbative schemes to sum the so-called
folded diagrams are critically reviewed, with an emphasis on the intruder state
problem. The methods we study are the approaches of Kuo and co-workers and Lee
and Suzuki. The suitability of the two schemes for shell-model calculations are
discussed.Comment: 10 pages in revtex ver. 3.0. 3 figs can be obtained upon request.
Univerisity of Oslo report UiO/PHYS/93-2
Probabilistic Value Selection for Space Efficient Model
An alternative to current mainstream preprocessing methods is proposed: Value
Selection (VS). Unlike the existing methods such as feature selection that
removes features and instance selection that eliminates instances, value
selection eliminates the values (with respect to each feature) in the dataset
with two purposes: reducing the model size and preserving its accuracy. Two
probabilistic methods based on information theory's metric are proposed: PVS
and P + VS. Extensive experiments on the benchmark datasets with various sizes
are elaborated. Those results are compared with the existing preprocessing
methods such as feature selection, feature transformation, and instance
selection methods. Experiment results show that value selection can achieve the
balance between accuracy and model size reduction.Comment: Accepted in the 21st IEEE International Conference on Mobile Data
Management (July 2020
Alcohol-dysregulated miR-30a and miR-934 in head and neck squamous cell carcinoma.
BackgroundAlcohol consumption is a well-established risk factor for head and neck squamous cell carcinoma (HNSCC); however, the molecular mechanisms by which alcohol promotes HNSCC pathogenesis and progression remain poorly understood. Our study sought to identify microRNAs that are dysregulated in alcohol-associated HNSCC and investigate their contribution to the malignant phenotype.MethodUsing RNA-sequencing data from 136 HNSCC patients, we compared the expression levels of 1,046 microRNAs between drinking and non-drinking cohorts. Dysregulated microRNAs were verified by qRT-PCR in normal oral keratinocytes treated with biologically relevant doses of ethanol and acetaldehyde. The most promising microRNA candidates were investigated for their effects on cellular proliferation and invasion, sensitivity to cisplatin, and expression of cancer stem cell genes. Finally, putative target genes were identified and evaluated in vitro to further establish roles for these miRNAs in alcohol-associated HNSCC.ResultsFrom RNA-sequencing analysis we identified 8 miRNAs to be significantly upregulated in alcohol-associated HNSCCs. qRT-PCR experiments determined that among these candidates, miR-30a and miR-934 were the most highly upregulated in vitro by alcohol and acetaldehyde. Overexpression of miR-30a and miR-934 in normal and HNSCC cell lines produced up to a 2-fold increase in cellular proliferation, as well as induction of the anti-apoptotic gene BCL-2. Upon inhibition of these miRNAs, HNSCC cell lines exhibited increased sensitivity to cisplatin and reduced matrigel invasion. miRNA knockdown also indicated direct targeting of several tumor suppressor genes by miR-30a and miR-934.ConclusionsAlcohol induces the dysregulation of miR-30a and miR-934, which may play crucial roles in HNSCC pathogenesis and progression. Future investigation of the alcohol-mediated pathways effecting these transformations will prove valuable for furthering the understanding and treatment of alcohol-associated HNSCC
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