66 research outputs found

    An off-board quantum point contact as a sensitive detector of cantilever motion

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    Recent advances in the fabrication of microelectromechanical systems (MEMS) and their evolution into nanoelectromechanical systems (NEMS) have allowed researchers to measure extremely small forces, masses, and displacements. In particular, researchers have developed position transducers with resolution approaching the uncertainty limit set by quantum mechanics. The achievement of such resolution has implications not only for the detection of quantum behavior in mechanical systems, but also for a variety of other precision experiments including the bounding of deviations from Newtonian gravity at short distances and the measurement of single spins. Here we demonstrate the use of a quantum point contact (QPC) as a sensitive displacement detector capable of sensing the low-temperature thermal motion of a nearby micromechanical cantilever. Advantages of this approach include versatility due to its off-board design, compatibility with nanoscale oscillators, and, with further development, the potential to achieve quantum limited displacement detection.Comment: 5 pages, 5 figure

    Maximization of propylene in an industrial FCC unit

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    YesThe FCC riser cracks gas oil into useful fuels such as gasoline, diesel and some lighter products such as ethylene and propylene, which are major building blocks for the polyethylene and polypropylene production. The production objective of the riser is usually the maximization of gasoline and diesel, but it can also be to maximize propylene. The optimization and parameter estimation of a six-lumped catalytic cracking reaction of gas oil in FCC is carried out to maximize the yield of propylene using an optimisation framework developed in gPROMS software 5.0 by optimizing mass flow rates and temperatures of catalyst and gas oil. The optimal values of 290.8 kg/s mass flow rate of catalyst and 53.4 kg/s mass flow rate of gas oil were obtained as propylene yield is maximized to give 8.95 wt%. When compared with the base case simulation value of 4.59 wt% propylene yield, the maximized propylene yield is increased by 95%

    Outcomes of pediatric patients with therapy-related myeloid neoplasms

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    Long-term outcomes after allogeneic hematopoietic cell transplantation (HCT) for therapy-related myeloid neoplasms (tMNs) are dismal. There are few multicenter studies defining prognostic factors in pediatric patients with tMNs. We have accumulated the largest cohort of pediatric patients who have undergone HCT for a tMN to perform a multivariate analysis defining factors predictive of long-term survival. Sixty-eight percent of the 401 patients underwent HCT using a myeloablative conditioning (MAC) regimen, but there were no statistically significant differences in the overall survival (OS), event-free survival (EFS), or cumulative incidence of relapse and non-relapse mortality based on the conditioning intensity. Among the recipients of MAC regimens, 38.4% of deaths were from treatment-related causes, especially acute graft versus host disease (GVHD) and end-organ failure, as compared to only 20.9% of deaths in the reduced-intensity conditioning (RIC) cohort. Exposure to total body irradiation (TBI) during conditioning and experiencing grade III/IV acute GVHD was associated with worse OS. In addition, a diagnosis of therapy-related myelodysplastic syndrome and having a structurally complex karyotype at tMN diagnosis were associated with worse EFS. Reduced-toxicity (but not reduced-intensity) regimens might help to decrease relapse while limiting mortality associated with TBI-based HCT conditioning in pediatric patients with tMNs

    Antibody responses to α-Gal in African children vary with age and site and are associated with malaria protection.

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    Naturally-acquired antibody responses to malaria parasites are not only directed to protein antigens but also to carbohydrates on the surface of Plasmodium protozoa. Immunoglobulin M responses to α-galactose (α-Gal) (Galα1-3Galβ1-4GlcNAc-R)-containing glycoconjugates have been associated with protection from P. falciparum infection and, as a result, these molecules are under consideration as vaccine targets; however there are limited field studies in endemic populations. We assessed a wide breadth of isotype and subclass antibody response to α-Gal in children from Mozambique (South East Africa) and Ghana (West Africa) by quantitative suspension array technology. We showed that anti-α-Gal IgM, IgG and IgG1-4 levels vary mainly depending on the age of the child, and also differ in magnitude in the two sites. At an individual level, the intensity of malaria exposure to P. falciparum and maternally-transferred antibodies affected the magnitude of α-Gal responses. There was evidence for a possible protective role of anti-α-Gal IgG3 and IgG4 antibodies. However, the most consistent findings were that the magnitude of IgM responses to α-Gal was associated with protection against clinical malaria over a one-year follow up period, especially in the first months of life, while IgG levels correlated with malaria risk

    Particle identification in ALICE : a Bayesian approach

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    Bio-affinity of copper(II) complexes with nitrogen and oxygen donor ligands: Synthesis, structural studies and in vitro DNA and HSA interaction of copper(II) complexes

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    Reported herein the binding affinity between Human Serum Albumin and the DNA binding and cleavage activity of three copper(II) complexes, [Cu(phen)(o-van)ClO4] (1), [Cu(phen)(gly)]ClO4 (2) and [Cu(L-1)(2)(H2O)(2)] (3) wherein 1 and 2 are synthesized with 1,10-phenanthroline (phen) and co-ligands (o-van: o-vanillin; gly: glycine) and 3 with a ligand 2-hydroxy-3-methoxybenzylidene-4H-1,2,4-triazol-4-amine (H1L1). Complex 2 crystallizes in monoclinic (P21/n) space group shows square pyramidal geometry. The complex 3 crystallizes in monoclinic (P21/a) space group. All the three complexes exhibit binding affinity towards the transport protein Human Serum albumin (HSA). Quantitative evaluation of the thermodynamics of interaction and the results obtained from fluorescence spectroscopy suggest that metal coordinated glycynate, o-vanillin and perchlorate groups have a major role to play in the binding process, the latter two being stronger in the binding of complex 1. The coordinated water in complex 3 also plays an important role in the binding, which makes binding of complex 3 with HSA stronger than that of complex 2. Experimental results indicate that the binding affinity of the complexes towards CT-DNA is in the order 1 > 3 > 2 implying that complex 1 binds stronger than complex 3 and 2.The DNA cleaving activity of all the three complexes was explored in the presence of reactive oxygen compound, H2O2. All the three complexes have primarily shown the DNA cleaving activity
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