7,485 research outputs found
Moving Stationary State of Exciton-Phonon Condensate in Cu2O
We explore a simple theoretical model to describe the properties of Bose
condensed para-excitons in Cu2O. Taking into account the exciton-phonon
interaction and introducing a coherent phonon part of the moving condensate, we
derive the dynamic equations for the exciton-phonon condensate. Within the Bose
approximation for excitons, we discuss the conditions for the moving
inhomogeneous condensate to appear in the crystal. We calculate the condensate
wave function and energy and a collective excitation spectrum in the
semiclassical approximation. The stability conditions of the moving condensate
are analyzed by use of Landau arguments, and two critical velocities appear in
the theory. Finally, we apply our model to describe the recently observed
interference between two coherent exciton-phonon packets in Cu2O.Comment: 20 pages (LaTeX), one figure (.ps) incorporated by epsf. Submitted to
Phys. Stat. Sol (B
Mitochondrial DNA Copy Number Is Associated with Breast Cancer Risk
Mitochondrial DNA (mtDNA) copy number in peripheral blood is associated with increased risk of several cancers. However, data from prospective studies on mtDNA copy number and breast cancer risk are lacking. We evaluated the association between mtDNA copy number in peripheral blood and breast cancer risk in a nested case-control study of 183 breast cancer cases with pre-diagnostic blood samples and 529 individually matched controls among participants of the Singapore Chinese Health Study. The mtDNA copy number was measured using real time PCR. Conditional logistic regression analyses showed that there was an overall positive association between mtDNA copy number and breast cancer risk (Ptrend = 0.01). The elevated risk for higher mtDNA copy numbers was primarily seen for women with <3 years between blood draw and cancer diagnosis; ORs (95% CIs) for 2nd, 3rd, 4th, and 5th quintile of mtDNA copy number were 1.52 (0.61, 3.82), 2.52 (1.03, 6.12), 3.12 (1.31, 7.43), and 3.06 (1.25, 7.47), respectively, compared with the 1st quintile (Ptrend = 0.004). There was no association between mtDNA copy number and breast cancer risk among women who donated a blood sample ≥3 years before breast cancer diagnosis (Ptrend = 0.41). This study supports a prospective association between increased mtDNA copy number and breast cancer risk that is dependent on the time interval between blood collection and breast cancer diagnosis. Future studies are warranted to confirm these findings and to elucidate the biological role of mtDNA copy number in breast cancer risk. © 2013 Thyagarajan et al
Electromagnetic emissions from the IC packaging
The EMC and EMI of the IC packaging are becoming increasingly important to modern electronics. Its EMC, SI, and PI have been broadly attested. But electromagnetic radiations from IC packaging and the corresponding EMI were seldom studied. In this paper, the fundamental principles and properties of the electromagnetic radiations caused by vias and traces in IC packagings are carefully investigated. Various radiation mechanisms are analyzed for different representative scenarios. Numerical simulations are employed to support the analyzing results. © 2012 IEEE.published_or_final_versio
Electromagnetic emissions from the IC packaging
The EMC and EMI of the IC packaging are becoming increasingly important to modern electronics. Its EMC, SI, and PI have been broadly attested. But electromagnetic radiations from IC packaging and the corresponding EMI were seldom studied. In this paper, the fundamental principles and properties of the electromagnetic radiations caused by vias and traces in IC packagings are carefully investigated. Various radiation mechanisms are analyzed for different representative scenarios. Numerical simulations are employed to support the analyzing results. © 2012 IEEE.published_or_final_versio
Region-based and pathway-based QTL mapping using a p-value combination method
Quantitative trait locus (QTL) mapping using deep DNA sequencing data is a challenging task. In this study we performed region-based and pathway-based QTL mappings using a p-value combination method to analyze the simulated quantitative traits Q1 and Q4 and the exome sequencing data. The aims were to evaluate the performance of the QTL mapping approaches that were used and to suggest plausible strategies for QTL mapping of DNA sequencing data. We conducted single-locus QTL mappings using a linear regression model with adjustments for age and smoking status, and we also conducted region-based and pathway-based QTL mappings using a truncated product method for combining p-values from the single-locus QTL mapping. To account for the features of rare variants and common single-nucleotide polymorphisms (SNPs), we considered independently rare-variant-only, common-SNP-only, and combined analyses. An analysis of 200 simulated replications showed that the three region-based methods reasonably controlled type I error, whereas the combined analysis yielded the greatest statistical power. Rare-variant-only, common-SNP-only, and combined analyses were also applied to pathway-based QTL mappings. We found that pathway-based QTL mappings had a power of approximately 100% when the significance of the vascular endothelial growth factor pathway was evaluated, but type I errors were slightly inflated. Our approach complements single-locus QTL mapping. An integrated approach using single-locus, combined region-based, and combined pathway-based analyses should yield promising results for QTL mapping of DNA sequencing data
Pro-inflammatory miR-223 mediates the cross-talk between the IL23 pathway and the intestinal barrier in inflammatory bowel disease
Genes that showed greater than four-fold upregulation in IBD. (XLSX 28 kb
MicroRNA-143 is a potential tumor suppressor targeting DNA methyltransferases 3a in colorectal cancer
Gastroenterology, 2009, v. 136 n. 5, suppl.1, p. A165, abstract no. 10692009 DDW (Digestive Disease Week) Abstract Supplement , AGA (American Gastroenterological Association) Institute Topic Forum, Oral sessions: Scientific sessions: Microrna and digestive cancers, Oral presentation no. 1069postprin
ITPKC Single Nucleotide Polymorphism Associated with the Kawasaki Disease in a Taiwanese Population
Kawasaki disease (KD) is characterized by systemic vasculitis with unknown etiology. Previous studies from Japan indicated that a gene polymorphism of ITPKC (rs28493229) is responsible for susceptibility to KD. We collected DNA samples from 1,531 Taiwanese subjects (341 KD patients and 1,190 controls) for genotyping ITPKC. In this study, no significant association was noted for the ITPKC polymorphism (rs28493229) between the controls and KD patients, although the CC genotype was overrepresented. We further combined our data with previously published case/control KD studies in the Taiwanese population and performed a meta-analysis. A significant association between rs28493229 and KD was found (Odds Ratio:1.36, 95% Confidence Interval 1.12–1.66). Importantly, a significant association was obtained between rs28493229 and KD patients with aneurysm formation (P = 0.001, under the recessive model). Taken together, our results indicated that C-allele of ITPKC SNP rs28493229 is associated with the susceptibility and aneurysm formation in KD patients in a Taiwanese population
Flexibility and extracellular opening determine the interaction between ligands and insect sulfakinin receptors
Despite their fundamental importance for growth, the mechanisms that regulate food intake are poorly understood. Our previous work demonstrated that insect sulfakinin (SK) signaling is involved in inhibiting feeding in an important model and pest insect, the red flour beetle Tribolium castaneum. Because the interaction of SK peptide and SK receptors (SKR) initiates the SK signaling, we have special interest on the structural factors that influence the SK-SKR interaction. First, the three-dimensional structures of the two T. castaneum SKRs (TcSKR1 and TcSKR2) were generated from molecular modeling and they displayed significance in terms of the outer opening of the cavity and protein flexibility. TcSKR1 contained a larger outer opening of the cavity than that in TcSKR2, which allows ligands a deep access into the cavity through cell membrane. Second, normal mode analysis revealed that TcSKR1 was more flexible than TcSKR2 during receptor-ligand interaction. Third, the sulfated SK (sSK) and sSK-related peptides were more potent than the nonsulfated SK, suggesting the importance of the sulfate moiety
Hmong Adults Self-Rated Oral Health: A Pilot Study
Since 1975, the Hmong refugee population in the U.S. has increased over 200%. However, little is known about their dental needs or self-rated oral health (SROH). The study aims were to: (1) describe the SROH, self-rated general health (SRGH), and use of dental/physician services; and (2) identify the factors associated with SROH among Hmong adults. A cross-sectional study design with locating sampling methodology was used. Oral health questionnaire was administered to assess SROH and SRGH, past dental and physician visits, and language preference. One hundred twenty adults aged 18–50+ were recruited and 118 had useable information. Of these, 49% rated their oral health as poor/fair and 30% rated their general health as poor/fair. Thirty-nine percent reported that they did not have a regular source of dental care, 46% rated their access to dental care as poor/fair, 43% visited a dentist and 66% visited a physician within the past 12 months. Bivariate analyses demonstrated that access to dental care, past dental visits, age and SRGH were significantly associated with SROH (P \u3c 0.05). Multivariate analyses demonstrated a strong association between access to dental care and good/excellent SROH. About half of Hmong adults rated their oral health and access to dental care as poor. Dental insurance, access to dental care, past preventive dental/physician visits and SRGH were associated with SROH
- …