1,404 research outputs found
Chirped pulse Raman amplification in warm plasma: towards controlling saturation
Stimulated Raman backscattering in plasma is potentially an efficient method of amplifying laser pulses to reach exawatt powers because plasma is fully broken down and withstands extremely high electric fields. Plasma also has unique nonlinear optical properties that allow simultaneous compression of optical pulses to ultra-short durations. However, current measured efficiencies are limited to several percent. Here we investigate Raman amplification of short duration seed pulses with different chirp rates using a chirped pump pulse in a preformed plasma waveguide. We identify electron trapping and wavebreaking as the main saturation mechanisms, which lead to spectral broadening and gain saturation when the seed reaches several millijoules for durations of 10's - 100's fs for 250 ps, 800 nm chirped pump pulses. We show that this prevents access to the nonlinear regime and limits the efficiency, and interpret the experimental results using slowly-varying-amplitude, current-averaged particle-in-cell simulations. We also propose methods for achieving higher efficiencies.close0
Gene and protein expression of glucose transporter 1 and glucose transporter 3 in human laryngeal cancer—the relationship with regulatory hypoxia-inducible factor-1α expression, tumor invasiveness, and patient prognosis
Increased glucose uptake mediated by glucose
transporters and reliance on glycolysis are common features
of malignant cells. Hypoxia-inducible factor-1α supports the
adaptation of hypoxic cells by inducing genes related to
glucose metabolism. The contribution of glucose transporter
(GLUT) and hypoxia-inducible factor-1α (HIF-1α) activity to
tumor behavior and their prognostic value in head and neck
cancers remains unclear. The aim of this study was to examine
the predictive value of GLUT1, GLUT3, and HIF-1α messenger
RNA (mRNA)/protein expression as markers of tumor
aggressiveness and prognosis in laryngeal cancer. The level of
hypoxia/metabolic marker genes was determined in 106 squamous
cell laryngeal cancer (SCC) and 73 noncancerous
matched mucosa (NCM) controls using quantitative realtime
PCR. The related protein levels were analyzed by
Western blot. Positive expression of SLC2A1, SLC2A3, and
HIF-1α genes was noted in 83.9, 82.1, and 71.7 % of SCC
specimens and in 34.4, 59.4, and 62.5 % of laryngeal cancer
samples. Higher levels of mRNA/protein for GLUT1 and
HIF-1α were noted in SCC compared to NCM (p<0.05).
SLC2A1 was found to have a positive relationship with grade,
tumor front grading (TFG) score, and depth and mode of
invasion (p<0.05). SLC2A3 was related to grade and invasion
type (p<0.05). There were also relationships of HIF-1α with
pTNM, TFG scale, invasion depth and mode, tumor recurrences,
and overall survival (p<0.05). In addition, more advanced
tumors were found to be more likely to demonstrate
positive expression of these proteins. In conclusion, the
hypoxia/metabolic markers studied could be used as molecular
markers of tumor invasiveness in laryngeal cancer.This work was supported, in part, by the statutory
fund of the Department of Cytobiochemistry, University of Łódź, Poland
(506/811), and by grant fromtheNational Science Council, Poland (N403
043 32/2326)
Experimental measurement-based quantum computing beyond the cluster-state model
The paradigm of measurement-based quantum computation opens new experimental
avenues to realize a quantum computer and deepens our understanding of quantum
physics. Measurement-based quantum computation starts from a highly entangled
universal resource state. For years, clusters states have been the only known
universal resources. Surprisingly, a novel framework namely quantum computation
in correlation space has opened new routes to implement measurement-based
quantum computation based on quantum states possessing entanglement properties
different from cluster states. Here we report an experimental demonstration of
every building block of such a model. With a four-qubit and a six-qubit state
as distinct from cluster states, we have realized a universal set of
single-qubit rotations, two-qubit entangling gates and further Deutsch's
algorithm. Besides being of fundamental interest, our experiment proves
in-principle the feasibility of universal measurement-based quantum computation
without using cluster states, which represents a new approach towards the
realization of a quantum computer.Comment: 26 pages, final version, comments welcom
PMeS: Prediction of Methylation Sites Based on Enhanced Feature Encoding Scheme
Protein methylation is predominantly found on lysine and arginine residues, and carries many important biological functions, including gene regulation and signal transduction. Given their important involvement in gene expression, protein methylation and their regulatory enzymes are implicated in a variety of human disease states such as cancer, coronary heart disease and neurodegenerative disorders. Thus, identification of methylation sites can be very helpful for the drug designs of various related diseases. In this study, we developed a method called PMeS to improve the prediction of protein methylation sites based on an enhanced feature encoding scheme and support vector machine. The enhanced feature encoding scheme was composed of the sparse property coding, normalized van der Waals volume, position weight amino acid composition and accessible surface area. The PMeS achieved a promising performance with a sensitivity of 92.45%, a specificity of 93.18%, an accuracy of 92.82% and a Matthew’s correlation coefficient of 85.69% for arginine as well as a sensitivity of 84.38%, a specificity of 93.94%, an accuracy of 89.16% and a Matthew’s correlation coefficient of 78.68% for lysine in 10-fold cross validation. Compared with other existing methods, the PMeS provides better predictive performance and greater robustness. It can be anticipated that the PMeS might be useful to guide future experiments needed to identify potential methylation sites in proteins of interest. The online service is available at http://bioinfo.ncu.edu.cn/inquiries_PMeS.aspx
Comparison of Whole Blood and Peripheral Blood Mononuclear Cell Gene Expression for Evaluation of the Perioperative Inflammatory Response in Patients with Advanced Heart Failure
Background: Heart failure (HF) prevalence is increasing in the United States.
Mechanical Circulatory Support (MCS) therapy is an option for Advanced HF
(AdHF) patients. Perioperatively, multiorgan dysfunction (MOD) is linked to the
effects of device implantation, augmented by preexisting HF. Early recognition of
MOD allows for better diagnosis, treatment, and risk prediction. Gene expression
profiling (GEP) was used to evaluate clinical phenotypes of peripheral blood
mononuclear cells (PBMC) transcriptomes obtained from patients’ blood samples.
Whole blood (WB) samples are clinically more feasible, but their performance in
comparison to PBMC samples has not been determined.
Methods: We collected blood samples from 31 HF patients (57¡15 years old)
undergoing cardiothoracic surgery and 7 healthy age-matched controls, between
2010 and 2011, at a single institution. WB and PBMC samples were collected at a
single timepoint postoperatively (median day 8 postoperatively) (25–75% IQR 7–14
days) and subjected to Illumina single color Human BeadChip HT12 v4 whole
genome expression array analysis. The Sequential Organ Failure Assessment
(SOFA) score was used to characterize the severity of MOD into low (# 4 points),
intermediate (5–11), and high ($ 12) risk categories correlating with GEP.
Results: Results indicate that the direction of change in GEP of individuals with
MOD as compared to controls is similar when determined from PBMC versus WB.
The main enriched terms by Gene Ontology (GO) analysis included those involved
in the inflammatory response, apoptosis, and other stress response related
pathways. The data revealed 35 significant GO categories and 26 pathways
overlapping between PBMC and WB. Additionally, class prediction using machine
learning tools demonstrated that the subset of significant genes shared by PBMC
and WB are sufficient to train as a predictor separating the SOFA groups.
Conclusion: GEP analysis of WB has the potential to become a clinical tool for
immune-monitoring in patients with MO
Isotocin controls ion regulation through regulating ionocyte progenitor differentiation and proliferation
The present study using zebrafish as a model explores the role of isotocin, a homolog of oxytocin, in controlling ion regulatory mechanisms. Double-deionized water treatment for 24 h significantly stimulated isotocin mRNA expression in zebrafish embryos. Whole-body Cl−, Ca2+, and Na+ contents, mRNA expressions of ion transporters and ionocyte-differentiation related transcription factors, and the number of skin ionocytes decreased in isotocin morphants. In contrast, overexpression of isotocin caused an increase in ionocyte numbers. Isotocin morpholino caused significant suppression of foxi3a mRNA expression, while isotocin cRNA stimulated foxi3a mRNA expressions at the tail-bud stage of zebrafish embryos. The density of P63 (an epidermal stem cell marker)-positive cells was downregulated by isotocin morpholinos and was upregulated by isotocin cRNA. Taken together, isotocin stimulates the proliferation of epidermal stem cells and differentiation of ionocyte progenitors by regulating the P63 and Foxi3a transcription factors, consequently enhancing the functional activities of ionocytes
Feasibility Study of Dual Energy Radiographic Imaging for Target Localization in Radiotherapy for Lung Tumors
Purpose
Dual-energy (DE) radiographic imaging improves tissue discrimination by separating soft from hard tissues in the acquired images. This study was to establish a mathematic model of DE imaging based on intrinsic properties of tissues and quantitatively evaluate the feasibility of applying the DE imaging technique to tumor localization in radiotherapy.
Methods
We investigated the dependence of DE image quality on the radiological equivalent path length (EPL) of tissues with two phantoms using a stereoscopic x-ray imaging unit. 10 lung cancer patients who underwent radiotherapy each with gold markers implanted in the tumor were enrolled in the study approved by the hospital's Ethics Committee. The displacements of the centroids of the delineated gross tumor volumes (GTVs) in the digitally reconstructed radiograph (DRR) and in the bone-canceled DE image were compared with the averaged displacements of the centroids of gold markers to evaluate the feasibility of using DE imaging for tumor localization.
Results
The results of the phantom study indicated that the contrast-to-noise ratio (CNR) was linearly dependent on the difference of EPL and a mathematical model was established. The objects and backgrounds corresponding to ΔEPL less than 0.08 are visually indistinguishable in the bone-canceled DE image. The analysis of patient data showed that the tumor contrast in the bone-canceled images was improved significantly as compared with that in the original radiographic images and the accuracy of tumor localization using the DE imaging technique was comparable with that of using fiducial makers.
Conclusion
It is feasible to apply the technique for tumor localization in radiotherapy
Observation of a ppb mass threshoud enhancement in \psi^\prime\to\pi^+\pi^-J/\psi(J/\psi\to\gamma p\bar{p}) decay
The decay channel
is studied using a sample of events collected
by the BESIII experiment at BEPCII. A strong enhancement at threshold is
observed in the invariant mass spectrum. The enhancement can be fit
with an -wave Breit-Wigner resonance function with a resulting peak mass of
and a
narrow width that is at the 90% confidence level.
These results are consistent with published BESII results. These mass and width
values do not match with those of any known meson resonance.Comment: 5 pages, 3 figures, submitted to Chinese Physics
Plasma Heme Oxygenase-1 Concentration in Relation to Impaired Glucose Regulation in a Non-Diabetic Chinese Population
Background: Our previous study has recently shown that plasma heme oxygenase-1 (HO-1), a stress-responsive protein, is elevated in individuals with type 2 diabetes. The current study aimed to examine the association between plasma HO-1 concentration and impaired glucose regulation (IGR) in non-diabetic individuals. Methods: We conducted a case-control study including a total of 865 subjects (262 IGR individuals and 603 healthy controls) in a Chinese population. Basic characteristics were collected by questionnaire and standardized anthropometric measurements. Plasma HO-1 concentration was determined by ELISA. Results: Plasma HO-1 concentration was significantly increased in IGR individuals compared with healthy controls (1.34 (0.81–2.29) ng/ml vs 0.98 (0.56–1.55) ng/ml, P,0.001). After adjustment for age, sex, and BMI, the ORs for IGR in the highest quartile of plasma HO-1 concentrations, compared with the lowest, was 3.42 (95 % CI 2.11–5.54; P for trend,0.001). The trend remained significant even after additional adjustment for smoking, alcohol drinking, hypertension, family history of diabetes, lipid profiles and C-reactive protein. In the receiver-operating characteristic curve analysis, addition of plasma HO-1 concentration to a model with known risk factors yielded significantly improved discriminative value for IGR (area under the curves 0.75 (95 % CI 0.71–0.78) vs. 0.72 (95 % CI 0.69–0.76); P for difference = 0.026)
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