5,095 research outputs found
Effective process for lipid reduction using high speed centrifugation compared with ultracentrifugation
Introduction: Reducing laboratory errors and improving patient safety is receiving a lot of attention. Lipaemic samples are cause of analytical errors and present challenges for laboratories, particularly for those without ultracentrifuges. Lipaemia can originate from physiological (postprandial metabo-lism), para-physiological causes (e.g. IV administration of lipids) as well as metabolic disturbances (e.g. hypertriglyceridaemia).
Materials and methods: We have evaluated a procedure with 10 native lipaemic sample pools (triglyceride concentration range 11.6-42.7 mmol/L) for the ability to reduce lipid concentration using a high speed micro-centrifuge (double centrifuged at 21.885 x g for 15 min) compared with an ultracen-trifuge, and provide accurate results. Results of sodium, creatinine, urate, total protein, lactate dehydrogenase (LD), magnesium and, cholesterol and triglyceride analysis on a Beckman DxC800 analyser are presented.
Results: Data from our tertiary level hospital showed ~0.7% of the samples received for lipid studies have triglyceride levels > 10 mmol/L which can potentially cause analytical interference. The mean differences from the neat aliquot to the ultracentrifuged and high speed centrifuged sample pools were: cholesterol 4.9 mmol/L and 3.1 mmol/L; and triglycerides 17.4 mmol/L and 15.0 mmol/L respectively. The data confirms high speed centrifugation is almost as effective as ultracentrifugation in lipid reduction.
Conclusion: The procedure utilized in this study using a high speed micro-centrifuge showed it is effective in reducing lipid levels and provides a suitable alternative to ultracentrifuged samples to pro-vide accurate results
Alterations of immune response of non-small lung cancer with azacytidine
Innovative therapies are needed for advanced Non-Small Cell Lung Cancer (NSCLC). We have undertaken a genomics based, hypothesis driving, approach to query an emerging potential that epigenetic therapy may sensitize to immune checkpoint therapy targeting PD-L1/PD-1 interaction. NSCLC cell lines were treated with the DNA hypomethylating agent azacytidine (AZA - Vidaza) and genes and pathways altered were mapped by genome-wide expression and DNA methylation analyses. AZA-induced pathways were analyzed in The Cancer Genome Atlas (TCGA) project by mapping the derived gene signatures in hundreds of lung adeno (LUAD) and squamous cell carcinoma (LUSC) samples. AZA up-regulates genes and pathways related to both innate and adaptive immunity and genes related to immune evasion in a several NSCLC lines. DNA hypermethylation and low expression of IRF7, an interferon transcription factor, tracks with this signature particularly in LUSC. In concert with these events, AZA up-regulates PD-L1 transcripts and protein, a key ligand-mediator of immune tolerance. Analysis of TCGA samples demonstrates that a significant proportion of primary NSCLC have low expression of AZA-induced immune genes, including PD-L1. We hypothesize that epigenetic therapy combined with blockade of immune checkpoints - in particular the PD-1/PD-L1 pathway - may augment response of NSCLC by shifting the balance between immune activation and immune inhibition, particularly in a subset of NSCLC with low expression of these pathways. Our studies define a biomarker strategy for response in a recently initiated trial to examine the potential of epigenetic therapy to sensitize patients with NSCLC to PD-1 immune checkpoint blockade
Developmental plasticity shapes social traits and selection in a facultatively eusocial bee
Developmental plasticity generates phenotypic variation, but how it contributes to evolutionary change is unclear. Phenotypes of individuals in caste-based (eusocial) societies are particularly sensitive to developmental processes, and the evolutionary origins of eusociality may be rooted in developmental plasticity of ancestral forms. We used an integrative genomics approach to evaluate the relationships among developmental plasticity, molecular evolution, and social behavior in a bee species (Megalopta genalis) that expresses flexible sociality, and thus provides a window into the factors that may have been important at the evolutionary origins of eusociality. We find that differences in social behavior are derived from genes that also regulate sex differentiation and metamorphosis. Positive selection on social traits is influenced by the function of these genes in development. We further identify evidence that social polyphenisms may become encoded in the genome via genetic changes in regulatory regions, specifically in transcription factor binding sites. Taken together, our results provide evidence that developmental plasticity provides the substrate for evolutionary novelty and shapes the selective landscape for molecular evolution in a major evolutionary innovation: Eusociality
In situ epitaxial MgB2 thin films for superconducting electronics
A thin film technology compatible with multilayer device fabrication is
critical for exploring the potential of the 39-K superconductor magnesium
diboride for superconducting electronics. Using a Hybrid Physical-Chemical
Vapor Deposition (HPCVD) process, it is shown that the high Mg vapor pressure
necessary to keep the MgB phase thermodynamically stable can be achieved
for the {\it in situ} growth of MgB thin films. The films grow epitaxially
on (0001) sapphire and (0001) 4H-SiC substrates and show a bulk-like of
39 K, a (4.2K) of A/cm in zero field, and a
of 29.2 T in parallel magnetic field. The surface is smooth with a
root-mean-square roughness of 2.5 nm for MgB films on SiC. This deposition
method opens tremendous opportunities for superconducting electronics using
MgB
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Mesomorphic behaviour in copoly(ester-imide)s of poly(butylene-2,6-naphthalate) (PBN)
Copolycondensation of N,N’-bis(4-hydroxybutyl)-biphenyl-3,4,3',4'-tetracarboxylic diimide at 20 and 25 mol% with bis(4-hydroxybutyl)-2,6-naphthalate produces PBN-based copoly(ester-imide)s that not only crystallise but also form a (smectic) mesophase upon cooling from the melt. Incorporation of 25 mol% imide in PBN causes the glass transition temperature (measured by DSC) to rise from 51 to 74 °C, a significant increase relative to PBN. Furthermore, increased storage- (G'), loss- (G'') and elastic (E) moduli are observed for both copoly(ester-imide)s when compared to PBN itself. Structural analysis of the 20 mol% copolymer by X-ray powder and fibre diffraction, interfaced to computational modelling, suggests a crystal structure related to that of α-PBN, in space group P-1, with cell dimensions a = 4.74, b = 6.38, c = 14.45 Å, α = 106.1, β = 122.1, γ = 97.3°, ρ = 1.37 g cm-3
A Study of the Semileptonic Charm Decays D^0 --> pi^- e^+ nu_e, D^+ --> pi^0 e^+ nu_e, D^0 --> K^- e^+ nu_e, and D^+ --> barK^0 e^+ nu_e
Using a sample of 1.8 million DDbar meson pairs collected at the psi(3770)
with the CLEO-c detector, we study the semileptonic decays D^0 -> pi^- e^+
nu_e, D^+ -> pi^0 e^+ \nu_e, D^0 -> K^- e^+ \nu_e, and D^+ -> Kbar^0 e^+ nu_e.
For the total branching fractions we find B(D^0 -> pi^- e^+ \nu_e) =
0.299(11)(9)%, B(D^+ -> pi^0 e^+ \nu_e) = 0.373(22)(13)%, B(D^0 -> K^- e^+
nu_e) = 3.56(3)(9)%, and B(D^+ -> Kbar^0 e^+ nu_e) = 8.53(13)(23)%, where the
first error is statistical and the second systematic. In addition, form factors
are studied through fits to the partial branching fractions obtained in five
q^2 ranges. By combining our results with recent unquenched lattice
calculations, we obtain |Vcd| = 0.217(9)(4)(23) and |Vcs| = 1.015(10)(11)(106),
where the final error is theoretical.Comment: 18 pages, postscript also available through
http://www.lns.cornell.edu/public/CLNS/2006/, submitted to PR
A Study of the Decays D^0 --> pi^- e^+ nu_e, D^0 --> K^- e^+ nu_e, D^+ --> pi^0 e^+ nu_e, and D^+ --> barK^0 e^+ nu_e
Using 1.8 million DDbar pairs and a neutrino reconstruction technique, we
have studied the decays D^0 -> K^- e^+ nu_e, D^0 -> pi^- e^+ nu_e, D^+ ->
Kbar^0 e^+ nu_e, and D^+ -> pi^0 e^+ nu_e. We find B(D^0 -> pi^- e^+ nu_e) =
0.299(11)(9)%, B(D^+ -> pi^0 e^+ nu_e) = 0.373(22)(13)%, B(D^0 -> K^- e^+ nu_e)
= 3.56(3)(9)%, and B(D^+ -> Kbar^0 e^+ nu_e) = 8.53(13)(23)%. In addition, form
factors are studied through fits to the partial branching fractions obtained in
five q^2 ranges. By combining our results with recent unquenched lattice
calculations, we obtain |Vcd| = 0.217(9)(4)(23) and |Vcs| = 1.015(10)(11)(106).Comment: 9 pages, postscript also available through
http://www.lns.cornell.edu/public/CLNS/2006/, submitted to PR
Search for Radiative Decays of Upsilon(1S) into eta and eta'
We report on a search for the radiative decay of Upsilon(1S) to the
pseudoscalar mesons eta and etaprime in 21.2 +/- 0.2 times 10^6 Upsilon(1S)
decays collected with the CLEO III detector at the Cornell Electron Storage
Ring (CESR). The eta meson was reconstructed in the three modes eta to
gamma-gamma, eta to pi+pi-pi0 and eta to 3pi0. The etaprime meson was
reconstructed in the mode etaprime to pi+ pi- eta with eta decaying through any
of the above three modes, and also etaprime to gamma rho, where rho decays to
pi^+ pi^-.
Five out of the seven sub-modes are found to be virtually background-free. In
four of them we find no signal candidates and in one Upsilon(1S) to
gamma-etaprime, etaprime to pi+ pi- eta, eta to pi+pi-pi0 there are two good
signal candidates, which is insufficient evidence to claim a signal. The other
two sub-modes eta to gamma-gamma and etaprime to gamma rho are background
limited, and show no excess of events in their signal regions. We combine the
results from different channels and obtain upper limits at the 90% C.L. which
are B(Upsilon(1S) to gamma eta) < 1.0 times 10^-6 and B(Upsilon(1S) to gamma
etaprime) < 1.9 times 10^-6. Our limits are an order of magnitude tighter than
the previous ones and below the predictions made by some theoretical models.Comment: 14 pages postscript,also available through
http://www.lns.cornell.edu/public/CLNS/2007/, Submitted to PR
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