674 research outputs found

    Synthesis gas production from biogas using Ni-based catalyst

    Get PDF
    As a result of global climate changes brought about by human activity, more sustainable sources of energy are being sought as alternatives to fossil fuels. Biomass is of particular interest as a sustainable source of energy since it does not contribute to net CO2 emissions. Reforming of methane derived from biomass with CO2 may form the basis of an efficient means to produce synthesis gas which has many applications m the petrochemical and allied industries. The objective of this study was the investigation of CO2 reforming of methane (simulating biogas) over effective supported nickel catalysts capable of long term operation without significant loss of activity and stability. [Continues.

    The role of inflammation and antiinflammation therapies in keratoconjunctivitis sicca

    Get PDF
    Koray Gumus1, Dwight H Cavanagh21Department of Ophthalmology, Erciyes University School of Medicine, Kayseri, Turkey; 2Department of Ophthalmology, The University of Texas Southwestern Medical Center, Dallas, Texas, USAPurpose: To review and integrate recent advances in identifying the role of inflammation in the pathogenesis of dry eye conditions and the biological rationale and practical clinical aspects of newer, antiinflammatory theories.Methods: A comprehensive literature survey. Results and conclusion: Keratoconjunctivitis Sicca (KCS) is a multifactorial and complex disorder in which ocular surface infl ammations play a central role. Identification of specific CD4-T-Cell pathways and the recent recognition of targeting of alpha-fodrin suggest a case for novel new therapeutic aspects such as anti-CD4 monoclonal antibodies, systemic linoleic and gamma-linolenic acids, and omega-6 essential fatty acids. Replacement of tear volume with nonpreserved wetting agents and standard typical antiinflammatory corticosteroid and/or cyclosporine A continues to be central current conventional therapy for KCS.Keywords: dry eye, keratoconjunctivitis sicca, antiinflammatory therap

    On Steady MHD Thermally Radiating and Reacting Thermosolutal Viscous Flow through a Channel with Porous Medium

    Get PDF
    This paper investigates steady-state solutions to MHD thermally radiating and reacting thermosolutal viscous flow through a channel with porous medium. The reaction is assumed to be strongly exothermic under generalized Arrhenius kinetics, neglecting the consumption of the material. Approximate solutions are constructed for the governing nonlinear boundary value problem using WKBJ approximations. The results, which are discussed with the aid of the dimensionless parameters entering the problem, are seen to depend sensitively on the parameters

    Recursive Partitioning Analysis of Mediastinal N2 Lymph Node Involvement with Selected Biological Markers in Operable Non-small Cell Lung Cancer: A Correlative Study

    Get PDF
    Background: Expressions of various biomarkers in non-small cell lung cancer (NSCLC) have been linked with the prognosis and involvement of mediastinal lymph nodes.Methods: In this study, we utilized recursive partitioning analysis (RPA) by using P53, c-erb-B2, and P-glycoprotein (PGP) expressions evaluated by immunohistochemistry to estimate retrospectively the likelihood of the occult N2 mediastinal lymph node involvement in patients with operable NSCLC.Results: In univariate tests, immunohistochemical staining of the primary tumor for these 3 markers in 61 patients undergoing surgery revealed no direct relationship with the N2 involvement. However, RPA demonstrated in patients aged 75 and with 4 mediastinal lymph nodes removed that, high PGP expression frequency (20%) predicted an increased likelihood of the N2 involvement (46.7%, R2 = 0.25). Univariate nominal logistic regression analysis revealed that RPA group affiliation, and the number of mediastinal lymph nodes resected (logarithmic transformation) were associated with the metastasis to N2 lymph nodes (χ2 = 17.59, p = 0.0005, and χ2 = 2.40, p = 0.0654, respectively). Multivariate analysis confirmed that only RPA group affiliation predicted the N2 involvement (χ2 = 14.63, p = 0.0022).Conclusion: This study shows for the first time that PGP expression of the primary tumor may help to predict the occult N2 mediastinal lymph node involvement in NSCLC. Thus, further research is required to understand whether PGP expression may aid in the decision process for preoperative mediastinoscopy

    Resistance/response molecular signature for oral tongue squamous cell carcinoma

    Get PDF
    Worldwide, the incidence of oral tongue cancer is on the rise, adding to the existing burden due to prevailing low survival and high recurrence rates. This study uses high-throughput expression profiling to identify candidate markers of resistance/response in patients with oral tongue cancer. Analysis of primary and post-treatment samples (12 tumor and 8 normal) by the Affymetrix platform (HG U133 plus 2) identified 119 genes as differentially regulated in recurrent tumors. The study groups had distinct profiles, with induction of immune response and apoptotic pathways in the non-recurrent and metastatic/invasiveness pathways in the recurrent group. Validation was carried out in tissues by Quantitative Real-Time PCR (QPCR) (n = 30) and Immunohistochemistry (IHC) (n = 35) and in saliva by QPCR (n = 37). The markers, COL5A1, HBB, IGLA and CTSC individually and COL5A1 and HBB in combination had the best predictive power for treatment response in the patients. A subset of markers identified (COL5A1, ABCG1, MMP1, IL8, FN1) could be detected in the saliva of patients with oral cancers with their combined sensitivity and specificity being 0.65 and 0.87 respectively. The study thus emphasizes the extreme prognostic value of exploring markers of treatment resistance that are expressed in both tissue and saliva

    Searching for Lee-Wick Gauge Bosons at the LHC

    Get PDF
    In an extension of the Standard Model(SM) based on the ideas of Lee and Wick, Grinstein, O'Connell and Wise have found an interesting way to remove the usual quadratically divergent contributions to the Higgs mass induced by radiative corrections. Phenomenologically, the model predicts the existence of Terascale, negative-norm copies of the usual SM fields with rather unique properties: ghost-like propagators and negative decay widths, but with otherwise SM-like couplings. The model is both unitary and causal on macroscopic scales. In this paper we examine whether or not such states with these unusual properties can be uniquely identified as such at the LHC. We find that in the extended strong and electroweak gauge boson sector of the model, which is the simplest one to analyze, such an identification can be rather difficult. Observation of heavy gluon-like resonances in the dijet channel offers the best hope for this identification.Comment: 17 pages, 4 figs; discussion adde

    Functional brain activity constrained by structural connectivity reveals cohort-specific features for serum neurofilament light chain

    Get PDF
    Background: Neuro-axonal brain damage releases neurofilament light chain (NfL) proteins, which enter the blood. Serum NfL has recently emerged as a promising biomarker for grading axonal damage, monitoring treatment responses, and prognosis in neurological diseases. Importantly, serum NfL levels also increase with aging, and the interpretation of serum NfL levels in neurological diseases is incomplete due to lack of a reliable model for age-related variation in serum NfL levels in healthy subjects. Methods: Graph signal processing (GSP) provides analytical tools, such as graph Fourier transform (GFT), to produce measures from functional dynamics of brain activity constrained by white matter anatomy. Here, we leveraged a set of features using GFT that quantified the coupling between blood oxygen level dependent signals and structural connectome to investigate their associations with serum NfL levels collected from healthy subjects and former athletes with history of concussions. Results: Here we show that GSP feature from isthmus cingulate in the right hemisphere (r-iCg) is strongly linked with serum NfL in healthy controls. In contrast, GSP features from temporal lobe and lingual areas in the left hemisphere and posterior cingulate in the right hemisphere are the most associated with serum NfL in former athletes. Additional analysis reveals that the GSP feature from r-iCg is associated with behavioral and structural measures that predict aggressive behavior in healthy controls and former athletes. Conclusions: Our results suggest that GSP-derived brain features may be included in models of baseline variance when evaluating NfL as a biomarker of neurological diseases and studying their impact on personality traits

    Structural and Optical Properties of Diluted Magnetic Ga1−xMnxAs–AlAs Quantum Wells Grown on High-Index GaAs Planes

    Get PDF
    We report on the structural and optical properties of Ga₁₋ᵪ Mn ᵪ As-AlAs quantum wells (QWs) with χ=0.1% grown by molecular beam epitaxy (MBE) on semi-insulating GaAs substrates with orientations (100), (110), (311)B and (411)B. Atomic force microscopy (AFM), X-ray diffraction (XRD) and photoluminescence (PL) techniques were used to investigate these QWs. AFM results have evidenced the formation of Mn-induced islands, which are randomly distributed on the surface. These islands tend to segregate for samples grown on (110) and (411)B planes, while no clear segregation was observed for samples grown on (100) and (311)B orientations. Results show that the PL line width increases with Mn segregation. XRD measurements were used to determine 2θ,d and cell parameters

    The effect of strain and spatial Bi distribution on the band alignment of GaAsBi single quantum well structure

    Get PDF
    The band line-up and band offset calculations of GaAs0.978Bi0.022/GaAs single quantum well with spatial changes of Bi composition were reported. The spatial Bi profile and a certain amount of the Bi composition in the barrier layer were determined by HR-XRD measurements. Virtual Crystal Approximation and Valence Band Anti-Crossing models were used including strain effects to obtain conduction and valence band edge shifts with Bi incorporation. Photoluminescence (PL) measurements were performed at a low temperature of 8 K as a function of excitation intensity. The PL spectra have shown asymmetric line shapes, which were fitted with different Gaussian functions. Comparing experimental PL results with calculated band edge energies, it was found that optical transition is a type I under low intensity excitation while the optical transition is switched from type I to type II due to the spatial changes in Bi concentrations. The band offsets?Ec/?Ev were also determined
    corecore