PrBaCo
2O
5+
δ
–Ce
0.8Sm
0.2O
1.9 (PBCO–SDC) composite material are prepared and characterized as cathode for intermediate temperature solid oxide fuel cells (IT-SOFCs). The powder X-ray diffraction ...result proves that there are no obvious reaction between the PBCO and SDC after calcination at 1100
°C for 3
h. AC impedance spectra based on SDC electrolyte measured at intermediate temperatures shows that the addition of SDC to PBCO improved remarkably the electrochemical performance of a PBCO cathode, and that a PBCO–30SDC cathode exhibits the best electrochemical performance in the PBCO–
xSDC system. The total interfacial resistances
R
p is the smallest when the content of SDC is 30
wt%, where the value is 0.035
Ω
cm
2 at 750
°C, 0.072
Ω
cm
2 at 700
°C, and 0.148
Ω
cm
2 at 650
°C, much lower than the corresponding interfacial resistance for pure PBCO. The maximum power density of an anode-supported single cell with PBCO–30SDC cathode, Ni–SDC anode, and dense thin SDC/LSGM (La
0.9Sr
0.1Ga
0.8Mg
0.2O
3−
δ
)/SDC tri-layer electrolyte are 364, 521 and 741
mW
cm
−2 at 700, 750 and 800
°C, respectively.
The electrochemical performance of Pr sub(0.7Sr) sub(0).3Co sub(0.9Cu) sub(0).1O sub(3-delta-xCe) sub(0).8 Sm sub(0.2O) sub(1).9 (PSCC-xSDC, x = 0-40 wt%) composite cathodes has been investigated for ...their potential utilization in intermediate-temperature solid oxide fuel cells (SOFCs). The results showed that the addition of SDC to PSCC improved remarkably the electrochemical performance of a PSCC cathode, and that a PSCC-35SDC cathode exhibited the best electrochemical performance in the PSCC-xSDC system. When SDC was used as the electrolyte, the interfacial resistance was smallest for 35 wt% SDC, where the value was 0.137 Omega cmsuper2 at 700 degC and 0.062 Omega cmsuper2 at 750 degC, much lower than the corresponding interfacial resistance for pure PSCC. At 700 degC, the cathodic overpotential of the PSCC-35SDC cathode in the SDC electrolyte was 70 mV at a current density of 0.5 A cmsuper-2. This is a factor of two lower than that for a pure PSCC cathode (152 mV at 700 degC) under the same current conditions. The maximum power density of a single-cell using PSCC-35SDC as the cathode was 388 and 615 mW cmsuper-2 at 650 and 700 degC, respectively.
The BaCo
0.7Fe
0.3−
y
Nb
y
O
3−
δ
oxides (BCFN
y,
y
=
0.00–0.12) were synthesized by the conventional solid state reaction process and investigated as a novel cathode for intermediate temperature ...solid oxide fuel cells(IT-SOFCs). Cubic perovskite, with enhanced phase stability at higher Nb concentration, was obtained at
y
⩾
0.04. The unit cell volumes increased with
y, reached a maximum at
y
=
0.10, and then decreased. The niobium doping concentration also had a significant effect on the electrochemical performance of BCFN
y materials. Among the various BCFN
y oxides tested, BCFN0.10 possessed the smallest interfacial polarization resistance (
R
p). The
R
p was as low as 0.9406, 0.1300, 0.0211, and 0.0082
Ω
cm
2 at 500, 600, 700, and 800
°C, respectively. With a 220
μm-thick Sm
0.2Ce
0.1O
1.9 (SDC) as electrolyte and BCFN0.10 as the cathode, a fuel cell provides maximum power densities of 202, 350, 569, 820, and 1006
mW
cm
−2 at 600, 650, 700, 750, and 800
°C, respectively. The encouraging results suggested that BCFN0.10 was a very promising cathode material for IT-SOFCs.
ABSTRACT Bacterial antibiotic efflux pumps are key players in antibiotic resistance. Although their role in conferring multidrug resistance is well documented, the emergence of “super” efflux pump ...variants that enhance bacterial resistance to multiple drugs has not been reported. Here, we describe the emergence of a resistance-enhancing variant (named RE-CmeABC) of the predominant efflux pump CmeABC in Campylobacter, a major zoonotic pathogen whose resistance to antibiotics is considered a serious antibiotic resistance threat in the United States. Compared to the previously characterized CmeABC transporters, RE-CmeABC is much more potent in conferring Campylobacter resistance to antibiotics, which was shown by increased MICs and reduced intracellular accumulation of antibiotics. Structural modeling suggests that sequence variations in the drug-binding pocket of CmeB possibly contribute to the enhanced efflux function. Additionally, RE-CmeABC expands the mutant selection window of ciprofloxacin, enhances the emergence of antibiotic-resistant mutants, and confers exceedingly high-level resistance to fluoroquinolones, an important class of antibiotics for clinical therapy of campylobacteriosis. Furthermore, RE-CmeABC is horizontally transferable, shifts antibiotic MIC distribution among clinical isolates, and is increasingly prevalent in Campylobacter jejuni isolates, suggesting that it confers a fitness advantage under antimicrobial selection. These findings reveal a new mechanism for enhanced multidrug resistance and an effective strategy utilized by bacteria for adaptation to selection from multiple antibiotics. IMPORTANCE Bacterial antibiotic efflux pumps are ubiquitously present in bacterial organisms and protect bacteria from the antibacterial effects of antimicrobials and other toxic compounds by extruding them out of cells. Thus, these efflux transporters represent an important mechanism for antibiotic resistance. In this study, we discovered the emergence and increasing prevalence of a unique efflux pump variant that is much more powerful in the efflux of antibiotics and confers multidrug resistance in Campylobacter, which is a major foodborne pathogen transmitted to humans via the food chain. Unlike other specific resistance determinants that only allow bacteria to resist a particular antimicrobial, the acquisition of a functionally enhanced efflux pump will empower bacteria with simultaneous resistance to multiple classes of antibiotics. These findings reveal a previously undescribed mechanism for enhanced multidrug resistance and open a new direction for us to understand how bacteria adapt to antibiotic treatment.
The electrochemical performance of Pr
0.7Sr
0.3Co
0.9Cu
0.1O
3−
δ
–
xCe
0.8Sm
0.2O
1.9 (PSCC–
xSDC,
x
=
0–40
wt%) composite cathodes has been investigated for their potential utilization in ...intermediate-temperature solid oxide fuel cells (SOFCs). The results showed that the addition of SDC to PSCC improved remarkably the electrochemical performance of a PSCC cathode, and that a PSCC–35SDC cathode exhibited the best electrochemical performance in the PSCC–
xSDC system. When SDC was used as the electrolyte, the interfacial resistance was smallest for 35
wt% SDC, where the value was 0.137
Ω
cm
2 at 700
°C and 0.062
Ω
cm
2 at 750
°C, much lower than the corresponding interfacial resistance for pure PSCC. At 700
°C, the cathodic overpotential of the PSCC–35SDC cathode in the SDC electrolyte was 70
mV at a current density of 0.5
A
cm
−2. This is a factor of two lower than that for a pure PSCC cathode (152
mV at 700
°C) under the same current conditions. The maximum power density of a single-cell using PSCC–35SDC as the cathode was 388 and 615
mW
cm
−2 at 650 and 700
°C, respectively.
Ce
0.85Sm
0.15O
1.925 (SDC) and La
0.9Sr
0.1Ga
0.8Mg
0.2O
2.85 (LSGM) were synthesized using Glycine-Nitrate Process (GNP), and the composite electrolytes were prepared by mixing SDC and LSGM. An ...X-ray diffraction pattern indicated that the mixture of SDC and LSGM consisted of their original phases after heating at 1450
oC for 10 h. The electronic conductivity of SDC-LSGM composite electrolytes were measured by direct current polarization method using Hebb-Wagner ion blocking cell at 700–800
oC in the oxygen partial pressure range of 10
−6–10
−20 MPa and compared with the results of SDC. Typical polarization curves, which were theoretically predicted, were observed on all the samples. The slopes of lg
σ
e
–lg
Po
2 plot for all the composite electrolytes agreed with the theoretically predicted value of −1/4 at some intermediate oxygen partial pressures and -1/6 at low oxygen partial pressure. The electronic conductivity of SDC-LSGM composite electrolytes decreased with the increase in LSGM content, whereas the ionic transport number
t
i of all the samples increased with the increase in LSGM content.
Illumination ratio images are presented in the paper to illuminate the faces. Our rendering method can simulate the distribution of the images with varying illuminations and generate new training ...images for face recognition with single frontal view. We analyzed the reason of the assumption that different persons have the same surface normal but different albedo. The synthesized images were compared with the original images by Gamma correction and error images. Our experiment shows that eyes are not lambertian surfaces. The synthesized images improve the face recognition performance by using the individual eigenface classifier.
A gas chromatography-mass spectrometry method was developed for the quantitative determination and confirmation of melamine and cyanuric acid in milk. The milk sample was extracted with ...diethylamine-acetonitrile-water solution. The extract was evaporated to dryness and derivatized with N, O-bis (trimethylsilyl) trifluoroacetamide (BSTFA) and chlorotrimethylsilane (TMCS), then analyzed using gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring (SIM) mode. The external standards were used for the quantitative determination. The linear range was from 0.025 to 2 mg/kg. The average recoveries were 84%-87% for melamine and 75%-102% for cyanuric acid, and the relative standard deviations were 5.7%-11.7% for melamine and 4.9%-7.8% for cyanuric acid in the spiked levels at 0.5, 1.0 and 2.5 mg/kg. The limits of detection of melamine and cyanuric acid were 0.05 mg/kg and 0.10 mg/kg, respectively. The method is suitable for the quantitative determination and confirmation of melainine and cyanuric acid residues in milk.
In the domain of large-scale software development, the demands for dynamic and multifaceted static code analysis exceed the capabilities of traditional tools. To bridge this gap, we present ...CodeFuse-Query, a system that redefines static code analysis through the fusion of Domain Optimized System Design and Logic Oriented Computation Design. CodeFuse-Query reimagines code analysis as a data computation task, support scanning over 10 billion lines of code daily and more than 300 different tasks. It optimizes resource utilization, prioritizes data reusability, applies incremental code extraction, and introduces tasks types specially for Code Change, underscoring its domain-optimized design. The system's logic-oriented facet employs Datalog, utilizing a unique two-tiered schema, COREF, to convert source code into data facts. Through Godel, a distinctive language, CodeFuse-Query enables formulation of complex tasks as logical expressions, harnessing Datalog's declarative prowess. This paper provides empirical evidence of CodeFuse-Query's transformative approach, demonstrating its robustness, scalability, and efficiency. We also highlight its real-world impact and diverse applications, emphasizing its potential to reshape the landscape of static code analysis in the context of large-scale software development.Furthermore, in the spirit of collaboration and advancing the field, our project is open-sourced and the repository is available for public access
Flow fields around a rotating circular cylinder in a uniform stream arecomputed using a low dimensional Galerkin method.Results show that the formationof a Fopple vortex pair behind a stationary ...circular cylinder is caused by the structuralinstability in the vicinity of the saddle located at the rear of the cylinder.For rotatingcylinder a bifurcation diagram with the consideration of two parameters,Reynoldsnumber Re and rotation parameter α,is built by a kinematic analysis of the steadyflow fields.
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