Treatment with effective antibiotics is one important strategy for syphilis control in China. This study aimed to evaluate the prevalence of azithromycin resistance to T. pallidum in China. A ...cross-sectional study was conducted among 391 patients with early syphilis recruited from STD clinics in eight cities during October 2008 and October 2011. The swabs were obtained from the moist lesions of the participating patients. A touchdown/nested PCR of the 23S ribosomal RNA (rRNA) gene was performed on DNA samples extracted from these specimens. The presence or absence of the A2058G point mutation, conferring resistance to azithromycin, was determined by restriction enzyme digestion analysis of the PCR amplicon by MboII. Two hundred and eleven patients with primary or secondary syphilis were found to have T. pallidum DNA in their moist lesions by PCR assays. The A2058G mutation was present in 91.9% (194/211, 95% CI, 87.2–95.1%) of these patients, with no significant differences noted between patients from the eastern part (93.8%), southern part (88.6%) and northern part (95.2%) of China (v2 = 2.303, p 0.316). Compared with patients who had not taken macrolides in previous years before study entry, the patients who had taken the antibiotics had a significantly higher prevalence of azithromycin resistance (97.0% vs. 62.5%), with an odds ratio of 19.65 (95% CI, 5.77–66.93). It can be concluded that prevalence of azithromycin resistance is substantial in China and consequently that the macrolides should not be used as a treatment option for early or incubating syphilis in China.
Abstract
At the interface between monolayer FeSe films and SrTiO
3
substrates the superconducting transition temperature (
T
c
) is unexpectedly high, triggering a surge of excitement. The mechanism ...for the
T
c
enhancement has been the central question, as it may present a new strategy for seeking out higher
T
c
materials. To reveal this enigmatic mechanism, by combining advances in high quality interface growth,
16
O
$$\leftrightarrow$$
↔
18
O isotope substitution, and extensive data from angle resolved photoemission spectroscopy, we provide striking evidence that the high
T
c
in FeSe/SrTiO
3
is the cooperative effect of the intrinsic pairing mechanism in the FeSe and interactions between the FeSe electrons and SrTiO
3
phonons. Furthermore, our results point to the promising prospect that similar cooperation between different Cooper pairing channels may be a general framework to understand and design high-temperature superconductors.
FeSe layer-based superconductors exhibit exotic and distinctive properties. The undoped FeSe shows nematicity and superconductivity, while the heavily electron-doped KxFe2-ySe2 and single-layer ...FeSe/SrTiO3 possess high superconducting transition temperatures that pose theoretical challenges. However, a comprehensive study on the doping dependence of an FeSe layer-based superconductor is still lacking due to the lack of a clean means of doping control. Through angle-resolved photoemission spectroscopy studies on K-dosed thick FeSe films and FeSe0.93S0.07 bulk crystals, here we reveal the internal connections between these two types of FeSe-based superconductors, and obtain superconductivity below ∼ 46 K in an FeSe layer under electron doping without interfacial effects. Moreover, we discover an exotic phase diagram of FeSe with electron doping, including a nematic phase, a superconducting dome, a correlation-driven insulating phase and a metallic phase. Such an anomalous phase diagram unveils the remarkable complexity, and highlights the importance of correlations in FeSe layer-based superconductors.
The interface between transition metal compounds provides a rich playground for emergent phenomena. Recently, significantly enhanced superconductivity has been reported for single-layer FeSe on ...Nb-doped SrTiO3 substrate. Yet it remains mysterious how the interface affects the superconductivity. Here we use in situ angle-resolved photoemission spectroscopy to investigate various FeSe-based heterostructures grown by molecular beam epitaxy, and uncover that electronic correlations and superconducting gap-closing temperature (Tg) are tuned by interfacial effects. Tg up to 75 K is observed in extremely tensile-strained single-layer FeSe on Nb-doped BaTiO3, which sets a record high pairing temperature for both Fe-based superconductor and monolayer-thick films, providing a promising prospect on realizing more cost-effective superconducting device. Moreover, our results exclude the direct correlation between superconductivity and tensile strain or the energy of an interfacial phonon mode, and highlight the critical and non-trivial role of FeSe/oxide interface on the high Tg, which provides new clues for understanding its origin.
Research on materials with pure organic room temperature phosphorescence (RTP) and their application as organic single-molecule white light emitters is a hot area and relies on the design of highly ...efficient pure organic RTP luminogens. Herein, a facile strategy of heavy-atom-participated anion-π
interactions is proposed to construct RTP-active organic salt compounds (1,2,3,4-tetraphenyloxazoliums with different counterions). Those compounds with heavy-atom counterions (bromide and iodide ions) exhibit outstanding RTP due to the external heavy atom effect via anion-π
interactions, evidently supported by the single-crystal X-ray diffraction analysis and theoretical calculation. Their single-molecule white light emission is realized by tuning the degree of crystallization. Such white light emission also performs well in polymer matrices and their use in 3D printing is demonstrated by white light lampshades.
After a decade of astonishing growth of wind power capacity worldwide, sustainable utilization of wind energy resources has become an issue of utmost importance. For a comprehensive assessment of the ...environmental sustainability of a wind power, basic emergy flow diagram and emergy indices are presented in this paper to aggregate various renewable/nonrenewable local resources and purchased economic inputs associated with a wind power system, with concrete illustration by a case study of a modern wind farm in Guangxi, China. It is revealed that the solar transformity of wind electricity is the lowest among typical electricity generation technologies. Emergy-based indices are then calculated to provide integrated information of the investigated wind farm from an ecological point of view. Comparison between the results with existing data for other renewable energy systems reflects the substantial advantages of wind power technology over solar thermal power and photovoltaic technologies in terms of sustainability and ecological cost. Nevertheless, biomass-derived fuels, especially biogas by anaerobic digestion, show a better ecological performance and environmental sustainability than wind and solar technologies. In addition, potential for improvements of Chinese wind farm are identified by optimization effort in human labor, land use and waste treatment.
Superconductivity in FeSe is greatly enhanced in films grown on SrTiO3 substrates, although the mechanism behind remains unclear. Recently, surface potassium (K) doping has also proven able to ...enhance the superconductivity of FeSe. Here, by using scanning tunneling microscopy, we compare the K doping dependence of the superconductivity in FeSe films grown on two substrates: SrTiO3 (001) and graphitized SiC (0001). For thick films (20 unit cells (UC)), the optimized superconducting (SC) gaps are of similar size (∼9 meV) regardless of the substrate. However, when the thickness is reduced to a few UC, the optimized SC gap is increased up to ∼15 meV for films on SrTiO3, whereas it remains unchanged for films on SiC. This clearly indicates that the FeSe/SrTiO3 interface can further enhance the superconductivity, beyond merely doping electrons. Intriguingly, we found that this interface enhancement decays exponentially as the thickness increases, with a decay length of 2.4 UC, which is much shorter than the length scale for relaxation of the lattice strain, pointing to interfacial electron–phonon coupling as the likely origin.
Summary
Background
The roles remain unclear of early on‐treatment quantitative serum HBsAg and hepatitis B virus (HBV) DNA levels in the prediction of a sustained response (SR) to peginterferon ...alfa‐2a therapy in HBeAg‐negative chronic hepatitis B (CHB) patients infected with genotype B or C.
Aims
To determine their roles in HBeAg‐negative CHB patients infected with genotype B or C.
Methods
Sixty‐one patients were treated with peginterferon alfa‐2a for 48 weeks. Serum HBsAg levels were quantified using the Abbott Architect HBsAg QT assay throughout treatment. Multiple regression analyses were performed to identify independent predictors of SR.
Results
Nineteen patients (31%) achieved SR with serum HBV DNA levels <312 copies/mL at 24 weeks post‐treatment. Serum HBsAg levels at 12 (OR 31.9; 95% CI 4.8–209.6; P = 0.0003) and 24 weeks of therapy (OR 8.8; 95% CI 2.0–38.0; P = 0.0035), and HBV DNA levels at baseline (OR 7.0; 95% CI 1.3–36.2; P = 0.0203), 12 (OR 7.9; 95% CI 1.2–48.4; P = 0.0249) and 24 weeks of therapy (OR 22.3; 95% CI 2.2–224.0; P = 0.0083) were early independent predictors of SR. A serum HBsAg cut‐off of 150 IU/mL at week 12 had an AUC, sensitivity, specificity and positive and negative predictive values of 0.75, 63%, 95%, 86% and 85% with respect to predicting SR respectively.
Conclusions
A quantitative serum HBsAg level at 12 weeks of therapy can be used for the early prediction of SR to peginterferon therapy in HBeAg‐negative CHB patients infected with genotype B or C.
Abstract
The interactions between electrons and antiferromagnetic magnons (AFMMs) are important for a large class of correlated materials. For example, they are the most plausible pairing glues in ...high-temperature superconductors, such as cuprates and iron-based superconductors. However, unlike electron-phonon interactions (EPIs), clear-cut observations regarding how electron-AFMM interactions (EAIs) affect the band structure are still lacking. Consequently, critical information on the EAIs, such as its strength and doping dependence, remains elusive. Here we directly observe that EAIs induce a kink structure in the band dispersion of Ba
1−
x
K
x
Mn
2
As
2
, and subsequently unveil several key characteristics of EAIs. We found that the coupling constant of EAIs can be as large as 5.4, and it shows strong doping dependence and temperature dependence, all in stark contrast to the behaviors of EPIs. The colossal renormalization of electron bands by EAIs enhances the density of states at Fermi energy, which is likely driving the emergent ferromagnetic state in Ba
1−
x
K
x
Mn
2
As
2
through a Stoner-like mechanism with mixed itinerant-local character. Our results expand the current knowledge of EAIs, which may facilitate the further understanding of many correlated materials where EAIs play a critical role.
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