6,130 research outputs found
Glueball relevant study on isoscalars from lattice QCD
We perform a glueball-relevant study on isoscalars based on anisotropic
lattice QCD gauge configurations. In the scalar channel, we identify
the ground state obtained through gluonic operators to be a single-particle
state through its dispersion relation. When operator is included, we
find the mass of this state does not change, and the operator
couples very weakly to this state. So this state is most likely a glueball
state. For pseudoscalars, along with the exiting lattice results, our study
implies that both the conventional state (or in
flavor ) and a heavier glueball-like state with a mass of roughly 2.6
GeV exist in the spectrum of lattice QCD with dynamical quarks.Comment: 8 pages, 3 figures, 3 tables, talk presented at the 35th
International Symposium on Lattice Field Theory, 18-24 June 2017, Granada,
Spai
Preparation, characterization, and antiproliferative activities of biotin-decorated docetaxel-loaded bovine serum albumin nanoparticles
The aim of the present study was to characterize biotin-decorated docetaxel-loaded bovine serum albumin nanoparticles (DTX-BIO-BSA-NPs) and evaluate their antiproliferative activity in vitro. The particle size of prepared DTX-BIO-BSA-NPs was found to be always lower than 200 nm, with sizes of 166.9, 160.3, 159.0, 176.1 and 184.8 nm and the zeta potential was -29.51, -28.54, -36.54, -36.08 and -27.56 mV after redissolution with water for 0, 1, 2, 4 and 8 hours, respectively. The polydispersity index (PDI) was stable in the range of 0.170 - 0.178. In the in vitro drug-release study, the DTX-BIO-BSA-NPs targeted a human breast cancer cell line MCF-7 effectively. The x-ray diffraction spectrum and DSC curve of DTX-BIO-BSA-NPs suggested that docetaxel was in an amorphous or disordered crystalline phase in DTX-BIO-BSA-NPs. In vitro cytotoxicity results showed that DTX-BIO-BSA-NPs inhibits proliferation of MCF-7, SGC7901, LS-174T and A549 cells in a concentration-dependent manner after exposure to DTX-BIO-BSA-NPs for 48 hours. Taken together, these results indicate that DTX-BIO-BSA-NPs may have potential as an alternative delivery system for parenteral administration of docetaxel
Selective low temperature chemical looping combustion of higher alkanes with Cu- and Mn- oxides
Chemical looping combustion (CLC) of n-hexadecane and n-heptane with copper and manganese oxides (CuO and Mn2O3) has been investigated in a fixed bed reactor to reveal the extent to which low temperature CLC can potentially be applicable to hydrocarbons. The effects of fuel to oxygen carrier ratio, fuel feed flow rate, and fuel residence time on the extent of combustion are reported. Methane did not combust, while near complete conversion was achieved for both n-hexadecane and n-heptane with excess oxygen carrier for CuO. For Mn2O3, complete reduction to Mn3O4 occurred, but the extent of combustion was controlled by the much slower reduction to MnO. Although the extent of cracking is relatively small in the absence of cracking catalysts, for the mechanism to be selective for higher hydrocarbons suggests that the reaction with oxygen involves radicals or carbocations arising from bond scission. Sintering of pure CuO occurred after repeated cycles, but this can easily be avoided using a support, such as alumina. The fact that higher hydrocarbons can be combusted selectively at 500 °C and below, offers the possibility of using CLC to remove these hydrocarbons and potentially other organics from hot gas streams
A novel approach to CO2 capture in Fluid Catalytic Cracking-Chemical Looping Combustion
Oil refineries collectively account for about 4–6% of global CO2 emissions and Fluid Catalytic Cracking (FCC) units are responsible for roughly 25% of these. Although post-combustion and oxy-combustion have been suggested to capture CO2 released from the regenerator of FCC units, Chemical Looping Combustion (CLC) is also a potential approach. In this study, the applicability of CLC for FCC units has been explored. A refinery FCC catalyst (equilibrium catalyst-ECat) was mixed mechanically with reduced oxygen carriers; Cu, Cu2O, CoO, and Mn3O4. To identify any detrimental effects of the reduced oxygen carriers on cracking, the catalyst formulations were tested for n-hexadecane cracking using ASTM D3907-13, the standard FCC microactivity test (MAT). To investigate the combustion reactivity of coke with physically mixed oxidised oxygen carriers, CuO, Co3O4 and Mn2O3, TGA tests were conducted on a low volatile semi-anthracite Welsh coal, which has a similar elemental composition to actual FCC coke, with various oxygen carrier to coke ratios over the temperature range 750–900 °C.The results demonstrated that, whereas Cu was detrimental for cracking n-hexadecane with the ECat, Cu2O, CoO, and Mn3O4 have no significant effects on gas, liquid and coke yields, and product selectivity. Complete combustion of the model coke was achieved with CuO, Co3O4 and Mn2O3, once the stoichiometric ratio of oxygen carrier/coke was higher than 1.0 and sufficient time had been provided. These results indicate that the proposed CLC-FCC concept has promise as a new approach to CO2 capture in FCC
Threatening Patch Attacks on Object Detection in Optical Remote Sensing Images
Advanced Patch Attacks (PAs) on object detection in natural images have
pointed out the great safety vulnerability in methods based on deep neural
networks. However, little attention has been paid to this topic in Optical
Remote Sensing Images (O-RSIs). To this end, we focus on this research, i.e.,
PAs on object detection in O-RSIs, and propose a more Threatening PA without
the scarification of the visual quality, dubbed TPA. Specifically, to address
the problem of inconsistency between local and global landscapes in existing
patch selection schemes, we propose leveraging the First-Order Difference (FOD)
of the objective function before and after masking to select the sub-patches to
be attacked. Further, considering the problem of gradient inundation when
applying existing coordinate-based loss to PAs directly, we design an IoU-based
objective function specific for PAs, dubbed Bounding box Drifting Loss (BDL),
which pushes the detected bounding boxes far from the initial ones until there
are no intersections between them. Finally, on two widely used benchmarks,
i.e., DIOR and DOTA, comprehensive evaluations of our TPA with four typical
detectors (Faster R-CNN, FCOS, RetinaNet, and YOLO-v4) witness its remarkable
effectiveness. To the best of our knowledge, this is the first attempt to study
the PAs on object detection in O-RSIs, and we hope this work can get our
readers interested in studying this topic
catena-Poly[[triaquazinc(II)]-μ-1H-1,2,4-triazole-3,5-dicarboxylato]
In the title compound, [Zn(C4HN3O4)(H2O)3]n, each ZnII atom adopts a distorted octahedral coordination geometry, being surrounded by one chelating and one monodentate 1H-1,2,4-triazole-3,5-dicarboxylate ligand and three water molecules. Adjacent ZnII cations are linked by a 1H-1,2,4-triazole-3,5-dicarboxylate ligand in a μ2,κ3 fashion to form a chain running along the c axis. The crystal packing is stabilized by N—H⋯O, O—H⋯N and O—H⋯O hydrogen bonds
catena-Poly[manganese(II)-(μ2-3,5-di-2-pyridyl-1,2,4-triazolato)-μ2-formato]
Owing to the presence of crystallographic twofold rotation axes (site symmetry 2, Wyckoff letters e and f), the asymmetric unit of the title compound, [Mn(C12H8N5)(CHO2)]n, contains one-half of an MnII cation, one-half of a bpt anion (Hbpt is 3,5-di-2-pyridyl-4H-1,2,4-triazole) and one-half of a formate anion. The bpt and formate ligands occupy the same C
2 symmetry, while the MnII ion resides on another crystallographic twofold rotation axis. Each bpt ligand acts as a cis-bis-chelate to ligate two MnII ions into a one-dimensional chain running along the crystallographic 41 screw axis. Adjacent MnII ions are further bridged by a μ2-formate ligand, completing the distorted octahedral coordination geometry of the cation
Biomedical and Forensic Applications of Combined Catalytic Hydrogenation-Stable Isotope Ratio Analysis
Studies of biological molecules such as fatty acids and the steroid hormones have the potential to benefit enormously from stable carbon isotope ratio measurements of individual molecules. In their natural form, however, the body’s molecules interact too readily with laboratory equipment designed to separate them for accurate measurements to be made. Some methods overcome this problem by adding carbon to the target molecule, but this can irreversibly overprint the carbon source ‘signal’. Hydropyrolysis is a newly-applied catalytic technique that delicately strips molecules of their functional groups but retains their carbon skeletons and stereochemistries intact, allowing precise determination of the carbon source. By solving analytical problems, the new technique is increasing the ability of scientists to pinpoint molecular indicators of disease, elucidate metabolic pathways and recognise administered substances in forensic investigations
Rashba-induced transverse pure spin currents in a four-terminal quantum dot ring
By applying a local Rashba spin-orbit interaction on an individual quantum
dot of a four-terminal four-quantum-dot ring and introducing a finite bias
between the longitudinal terminals, we theoretically investigate the charge and
spin currents in the transverse terminals. It is found that when the quantum
dot levels are separate from the chemical potentials of the transverse
terminals, notable pure spin currents appear in the transverse terminals with
the same amplitude and opposite polarization directions. Besides, the
polarization directions of such pure spin currents can be inverted by altering
structure parameters, i.e., the magnetic flux, the bias voltage, and the values
of quantum dot levels with respect to the chemical potentials of the transverse
terminals.Comment: 4 pages, 3 figures, Submitted to nanotechnolog
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