777 research outputs found
Three-dimensional manipulation of electron beam phase space for seeding soft x-ray free-electron lasers
In this letter, a simple technique is proposed to induce strong density
modulation into the electron beam with small energy modulation. By using the
combination of a transversely dispersed electron beam and a wave-front tilted
seed laser, three-dimensional manipulation of the electron beam phase space can
be utilized to significantly enhance the micro-bunching of seeded free-electron
laser schemes, which will improve the performance and extend the
short-wavelength range of a single-stage seeded free-electron laser.
Theoretical analysis and numerical simulations demonstrate the capability of
the proposed technique in a soft x-ray free-electron laser.Comment: 8 pages, 4 figure
Systematic computational identification of prognostic cytogenetic markers in neuroblastoma
Background: Neuroblastoma (NB) is the most common extracranial solid tumor found in children. The frequent gain/loss of many chromosome bands in tumor cells and absence of mutations found at diagnosis suggests that NB is a copy number-driven cancer. Despite the previous work, a systematic analysis that investigates the relationship between such frequent gain/loss of chromosome bands and patient prognosis has yet to be implemented. Methods: First, we analyzed two NB CNV datasets to select chromosomal bands with a high frequency of gain or loss. Second, we applied a computational approach to infer sample-specific CNVs for each chromosomal band selected in step 1 based on gene expression data. Third, we applied univariate Cox proportional hazards models to examine the association between the resulting inferred copy number values (iCNVs) and patient survival. Finally, we applied multivariate Cox proportional hazards models to select chromosomal bands that remained significantly associated with prognosis after adjusting for critical clinical variables, including age, stage, gender, and MYCN amplification status. Results: Here, we used a computational method to infer the copy number variations (CNVs) of sample-specific chromosome bands from NB patient gene expression profiles. The resulting inferred CNVs (iCNVs) were highly correlated with the experimentally determined CNVs, demonstrating CNVs can be accurately inferred from gene expression profiles. Using this iCNV metric, we identified 58 frequent gain/loss chromosome bands that were significantly associated with patient survival. Furthermore, we found that 7 chromosome bands were still significantly associated with patient survival even when clinical factors, such as MYCN status, were considered. Particularly, we found that the chromosome band chr11p14 has high potential as a novel candidate cytogenetic biomarker for clinical use. Conclusion: Our analysis resulted in a comprehensive list of prognostic chromosome bands supported by strong statistical evidence. In particular, the chr11p14 gain event provided additional prognostic value in addition to well-established clinical factors, including MYCN status, and thereby represents a novel candidate cytogenetic biomarker with high clinical potential. Additionally, this computational framework could be readily extended to other cancer types, such as leukemia
Further Study On U(1) Gauge Invariance Restoration
To further investigate the applicability of the projection scheme for
eliminating the unphysical divergence due to U(1) gauge invariance
violation, we study the process which possesses
advantages of simplicity and clearness. Our study indicates that the projection
scheme can indeed eliminate the unphysical divergence caused by the
U(1) gauge invariance violation and the scheme can apply to very high energy
region.Comment: Latex, 13 pages, 4 EPS fiure
11β-Hydroxysteroid Dehydrogenase Type 1(11β-HSD1) mediates insulin resistance through JNK activation in adipocytes
Glucocorticoids are used to treat a number of human diseases but often lead to insulin resistance and metabolic syndrome. 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) is a key enzyme that catalyzes the intracellular conversion of cortisone to physiologically active cortisol. Despite the known role of 11β-HSD1 and active glucocorticoid in causing insulin resistance, the molecular mechanisms by which insulin resistance is induced remain elusive. The aim of this study is to identify these mechanisms in high fat diet (HFD) experimental models. Mice on a HFD were treated with 11β-HSD1 inhibitor as well as a JNK inhibitor. We then treated 3T3-L1-derived adipocytes with prednisone, a synthetic glucocorticoid, and cells with 11β-HSD1 overexpression to study insulin resistance. Our results show that 11β-HSD1 and JNK inhibition mitigated insulin resistance in HFD mice. Prednisone stimulation or overexpression of 11β-HSD1 also caused JNK activation in cultured adipocytes. Inhibition of 11β-HSD1 blocked the activation of JNK in adipose tissue of HFD mice as well as in cultured adipocytes. Furthermore, prednisone significantly impaired the insulin signaling pathway, and these effects were reversed by 11β-HSD1 and JNK inhibition. Our study demonstrates that glucocorticoid-induced insulin resistance was dependent on 11β-HSD1, resulting in the critical activation of JNK signaling in adipocytes
An Improved Combined Current Control for Single-Phase Operation Mode of Single-/Three-Phase EV Charging System with Voltage Ripple Suppression
In this article, the control stage of an interesting versatile single-/three-phase electric vehicle (EV) charging system is studied in details. Therein, a typical three-phase two-level voltage source rectifier can be reconfigured to operate as a single-phase rectifier where two phase-legs operate with a pulsewidth modulation interleaving method and the grid neutral is connected to the midpoint of the dc-bus capacitors with the third leg operating as an active power decoupling (APD) circuit to reduce the current stress in the capacitors. To improve the performance of the single-phase operation while considering external grid voltage disturbances, first, an improved hybrid current control method combining deadbeat prediction current control (DPCC) with repetitive control (RC) is proposed in this article, where a modified RC is adopted to suppress the influence of the internal dc-bus capacitor voltage disturbance and to improve the harmonic control performance. Thereafter, via introducing the weighting factor Kf of the DPCC and by multiplexing the filter of RC in the DPCC output, the stability of the current loop under the influence of grid voltage distortion and grid impedance can be improved remarkably. Moreover, a grid-frequency voltage ripple suppression function implementing zero-voltage-switching turn-on for the APD circuit is achieved, improving the reliability of the converter. Finally, a 7.4-kW single-phase ac-dc converter prototype is built to verify the feasibility and effectiveness of the proposed method in the single-/three-phase EV charging system.</p
Exact Eigenfunctions of -Body system with Quadratic Pair Potential
We obtain all the exact eigenvalues and the corresponding eigenfunctions of
-body Bose and Fermi systems with Quadratic Pair Potentials in one
dimension. The originally existed first excited state level is missing in one
dimension, which results from the operation of symmetry or antisymmetry of
identical particles. In two and higher dimensions, we give all the eigenvalues
and the analytical ground state wave functions and the number of degeneracy.
Through the comparison with Avinash Khare's results, we have perfected his
results.Comment: 7 pages,1 figur
Involvement of MicroRNAs in Probiotics-Induced Reduction of the Cecal Inflammation by Salmonella Typhimurium
The microRNAs (miRNAs) have been shown to play important roles in the development of the immune system and in regulation of host inflammation responses. Probiotics can effectively alleviate the inflammation caused by Salmonella in chickens. However, whether and how miRNAs are involved in modulation of the inflammation response in the gut of chickens have not been reported. In this study, the impact of a probiotics, Lactobacillus plantarum Z01 (LPZ01), was investigated on the cecal miRNAs and cytokine secretions in Salmonella Typhimurium (S. Typhimurium)-infected chickens at the age of 3 days. Newly hatched chicks were assigned to four groups (1): NC (basal diet) (2): S (basal diet + S. Typhimurium challenged) (3): SP (basal diet + S. Typhimurium challenged + LPZ01) (4): P (basal diet + LPZ01). In comparison with the S group, chicks in the SP group reduced the number of S. Typhimurium and had lower levels of interferon-γ and lipopolysaccharide-induced tumor necrosis factor alpha factor (LITAF) in ceca post challenge. Expression of 14 miRNAs was significantly affected by the presence of S. Typhimurium and/or lactobacillus. Five differential expression miRNAs (gga-miR-215-5p, gga-miR-3525, gga-miR-193a-5p, gga-miR-122-5p, and gga-miR-375) were randomly selected for confirmation by the RT-PCR. Predicted target genes of differentially expressed miRNAs were enriched in regulation of cAMP-dependent protein kinase activity, stress-activated MAPK cascade, immune system development and regulation of immune system process as well as in immune related pathways such as MAPK and Wnt signaling pathways. The relationship between changes of miRNAs and changes of cytokines was explored. Finally, 119 novel miRNAs were identified in 36 libraries totally. Identification of novel miRNAs significantly expanded the repertoire of chicken miRNAs and provided the basis for understanding the function of miRNAs in the host. Our results suggest that the probiotics reduce the inflammation of the S. Typhimurium infection in neonatal broiler chicks, at least partially, through regulation of miRNAs expression
Corporate innovation and environmental investment:The moderating role of institutional environment
Corporate environmental investment helps improve corporate environmental performance, which, therefore, is an effective micro-level solution to mitigate environmental concerns generated by corporate excessive resource exploitation and energy use. Using Chinese listed firms within environment-related industries over the period 2011–2018 as the research setting, this study applies the panel data model to investigate the impact of corporate innovation on environmental investment, as well as the moderating effects of institutional factors. The results show that corporate innovation significantly improves firms' environmental investment with 1% Research & Development (R&D) investment ratio increase generating 2326 CNY (around 351 USD at 2018 exchange rate) increase in environmental investment; the moderating effect of environment policy is positive and significant while the moderating effect of internationalisation level is not significant, indicating that current environment policy implementation helps to strengthen the positive impact of corporate innovation on environmental investment while the role of internationalisation level in this nexus is not observed. From a micro-level perspective, the findings of this study shed light on mitigating environmental concerns through enhancing corporate innovation, and provide evidence that China's corporate internationalisation process awaits more regulatory controls
- …