655 research outputs found
Complexity measures and uncertainty relations of the high-dimensional harmonic and hydrogenic systems
In this work we find that not only the Heisenberg-like uncertainty products
and the R\'enyi-entropy-based uncertainty sum have the same first-order values
for all the quantum states of the -dimensional hydrogenic and
oscillator-like systems, respectively, in the pseudoclassical ()
limit but a similar phenomenon also happens for both the
Fisher-information-based uncertainty product and the Shannon-entropy-based
uncertainty sum, as well as for the Cr\'amer-Rao and Fisher-Shannon
complexities. Moreover, we show that the LMC (L\'opez-Ruiz-Mancini-Calvet) and
LMC-R\'enyi complexity measures capture the hydrogenic-harmonic difference in
the high dimensional limit already at first order
Advanced fuel cell based on Perovskite La-SrTiO3 semiconductor as the electrolyte with superoxide-ion conduction
A solid oxide fuel cell’s (SOFC) performance is largely determined by the ionic-conducting electrolyte. A novel approach is presented for using the semiconductor perovskite LaR0.25RSrR0.75RTiOR3R (LST) as the electrolyte by creating surface superionic conduction, and the authors show that the LST electrolyte can deliver superior power density, 908.2 mW·cmP-2P at just 550 °C. The prepared LST materials formed a heterostructure including an insulating core and a super ionic conducting surface layer. The rapid ion transport along the surfaces or grain boundaries was identified as the primary means of oxygen ion conduction. The fuel cell-induced phase transition was observed from the insulating LST to a super OP2-P conductivity of 0.221 S·cmP-1P at 550 °C, leading to excellent current and power outputs
Standardized procedures important for improving single-component ceramic fuel cell technology
Standardized procedures important for improving single-component ceramic fuel cell technolog
Facile Preparation of Graphene-Copper Nanoparticle Composite by in Situ Chemical Reduction for Electrochemical Sensing of Carbohydrates
A novel graphene-copper nanoparticle composite was prepared by the in situ chemical reduction of a mixture containing graphene oxide and copper(II) ions using potassium borohydride as a reductant. It was mixed with paraffin oil and packed into one end of a fused capillary to fabricate microdisc electrodes for sensing carbohydrates. The morphology and structure of the graphene-copper nanoparticle composite were investigated by scanning electron microscopy, X-ray diffraction, and Fourier transform-infrared spectroscopy. The results indicated that copper nanoparticles with an average diameter of 20.8 nm were successfully deposited on graphene nanosheets to form a well interconnected hybrid network. The analytical performance of these unique graphene-copper nanoparticle composite paste electrodes was demonstrated by sensing five carbohydrates in combination with cyclic voltammetry and capillary electrophoresis (CE). The advantages of the composite detectors include higher sensitivity, satisfactory stability, surface renewability, bulk modification, and low expense of fabrication. They should find applications in microchip CE, flowing-injection analysis, and other microfluidic analysis systems
generate_osc_v1.m
This script may be used to generate the profile of a near best-form Optimized Spline Concentrator (OSC) for any acceptance angle between 10 and 45 degrees, following the designs optimized using the tangent-normal perturbation approach
Germanene Growth on Al(111): A Case Study of Interface Effect
Using density functional
theory calculations, we have studied germanene
growth on Al(111) in detail. According to the polygons in Ge<i><sub>N</sub></i> (<i>N</i> = 1–12) structures
on a substrate, three structural growth modes are studied, which would
lead to the growths of single-atom-thick hexagonal lattice, Kagome
lattice, and buckled hexagonal superlattice germanenes. The buckled
superlattices grown on pure Al(111) could reproduce the experimental
scanning tunneling microscopy images, which however do not have good
energetic and thermal stabilities. Detailed energy analyses suggest
the possibility of forming an Al<sub>2</sub>Ge surface alloy, on which
the growths of the buckled superlattices turn to be preferable. Furthermore,
such superlattice configurations become energetically and thermally
stable. Their adhesive energy is ∼83 meV/Å<sup>2</sup>, which could be further decreased by hydrogenation to facilitate
their separations from the Al<sub>2</sub>Ge substrate. These studies
highlight the effects of interface modification on tuning two-dimensional
material growth. Also, surface alloying could be used as an effective
pretreatment method to facilitate large-quantity fabrication of germanene
on Al(111)
PbS/PbSe Hollow Spheres: Solvothermal Synthesis, Growth Mechanism, and Thermoelectric Transport Property
Uniform PbS/PbSe hollow spheres consisting of PbS and
PbSe nanoparticles
were synthesized by a facile solvothermal method in mixtures of ethylene
glycol and tetrahydrofuran at 120 °C with the assistance of thioglycollic
acid. Experimental parameters, such as reaction time, volume of thioglycollic
acid, and volume ratio of ethylene glycol to tetrahydrofuran, played
crucial roles in determining the morphologies and composites of the
final products. Based on the electron microscope observations and
X-ray diffraction (XRD) patterns, the reaction process and growth
mechanism of such hierarchitectures were proposed. Nitrogen adsorption–desorption
measurements and pore size distribution analysis revealed that the
mesoporous existed in the product. Moreover, thermoelectric transport
measurements demonstrated that the synergistic effects of PbS and
PbSe would lead to enhancement of the electrical conductivity; the
obtained binary phased PbS/PbSe hollow spheres had the maximum electrical
conductivity and Seebeck coefficient of 22.1 S cm<sup>–1</sup> and 323.3 μV/K, respectively, which were higher than those
of pure PbSe nanoparticles
Design, Synthesis, and Pharmacokinetics of a Bone-Targeting Dual-Action Prodrug for the Treatment of Osteoporosis
A dual-action
bone-targeting prodrug has been designed, synthesized,
and evaluated for in vitro and in vivo metabolic stability, in vivo
tissue distribution, and rates of release of the active constituents
after binding to bones through the use of differentially double-labeled
derivatives. The conjugate (general structure <b>7</b>) embodies
the merger of a very potent and proven anabolic selective agonist
of the prostaglandin EP4 receptor, compound <b>5</b>, and alendronic
acid, a potent inhibitor of bone resorption, optimally linked through
a differentially hydrolyzable linker unit, <i>N</i>-4-carboxymethylphenyl-methyloxycarbonyl-leucinyl-argininyl-<i>para</i>-aminophenylmethylalcohol (Leu-Arg-PABA). Optimized
conjugate <b>16</b> was designed so that esterase activity will
liberate <b>5</b> and cathepsin K cleavage of the Leu-Arg-PABA
element will liberate alendronic acid. Studies with doubly radiolabeled <b>16</b> provide a proof-of-concept for the use of a cathepsin K
cleavable peptide-linked conjugate for targeting of bisphosphonate
prodrugs to bone and slow release liberation of the active constituents
in vivo. Such conjugates are potential therapies for the treatment
of bone disorders such as osteoporosis
Determination of the Rat in Vivo Pharmacokinetic Profile of a Bone-Targeting Dual-Action Pro-Drug for Treatment of Osteoporosis
The in vivo hydrolytic pathway of
a dual-function bone-targeting
EP4 receptor agonist-bisphosphonate pro-drug was deduced from radiolabeling
experiments. A <sup>14</sup>C labeled pro-drug was used to monitor
liberation of the bisphosphonate and results were compared to parallel
studies where the EP4 receptor agonist was labeled with <sup>3</sup>H. The bone-adsorption of the <sup>14</sup>C pro-drug following an
IV bolus was about 10% compared to 7.8% for the tritiated pro-drug.
The difference in release half-life (5.2 and 19.7 days from <sup>3</sup>H and <sup>14</sup>C experiments, respectively) indicated that, after
binding to bone, the initial hydrolysis occurred at the ester moiety
of the linker releasing the EP4 agonist. The conjugate was found to
concentrate in more porous, high-surface-area regions of the long
bones. Both <sup>3</sup>H and <sup>14</sup>C experiments indicated
a short circulating half-life (1–2 h) in blood
Design, Synthesis, and Pharmacokinetics of a Bone-Targeting Dual-Action Prodrug for the Treatment of Osteoporosis
A dual-action
bone-targeting prodrug has been designed, synthesized,
and evaluated for in vitro and in vivo metabolic stability, in vivo
tissue distribution, and rates of release of the active constituents
after binding to bones through the use of differentially double-labeled
derivatives. The conjugate (general structure <b>7</b>) embodies
the merger of a very potent and proven anabolic selective agonist
of the prostaglandin EP4 receptor, compound <b>5</b>, and alendronic
acid, a potent inhibitor of bone resorption, optimally linked through
a differentially hydrolyzable linker unit, <i>N</i>-4-carboxymethylphenyl-methyloxycarbonyl-leucinyl-argininyl-<i>para</i>-aminophenylmethylalcohol (Leu-Arg-PABA). Optimized
conjugate <b>16</b> was designed so that esterase activity will
liberate <b>5</b> and cathepsin K cleavage of the Leu-Arg-PABA
element will liberate alendronic acid. Studies with doubly radiolabeled <b>16</b> provide a proof-of-concept for the use of a cathepsin K
cleavable peptide-linked conjugate for targeting of bisphosphonate
prodrugs to bone and slow release liberation of the active constituents
in vivo. Such conjugates are potential therapies for the treatment
of bone disorders such as osteoporosis
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