Prevailing Charge Order in Overdoped La_{2-x}Sr_{x}CuO_{4} beyond the Superconducting Dome.

The extremely overdoped cuprates are generally considered to be Fermi liquid metals without exotic orders, whereas the underdoped cuprates harbor intertwined states. Contrary to this conventional wisdom, using Cu L_{3}-edge and O K-edge resonant x-ray scattering, we reveal a charge order (CO) correlation in overdoped La_{2-x}Sr_{x}CuO_{4} (0.35≤x≤0.6) beyond the superconducting dome. This CO has a periodicity of ∼6 lattice units with correlation lengths of ∼20 lattice units. It shows similar in-plane momentum and polarization dependence and dispersive excitations as the CO of underdoped cuprates, but its maximum intensity differs along the c direction and persists up to 300 K. This CO correlation cannot be explained by the Fermi surface instability and its origin remains to be understood. Our results suggest that CO is prevailing in the overdoped metallic regime and requires a reassessment of the picture of overdoped cuprates as weakly correlated Fermi liquids.

Differential Refractive Index Sensor Based on Coupled Plasmon Waveguide Resonance in the C-Band.

We proposed a differential fiber-optic refractive index sensor based on coupled plasmon waveguide resonance (CPWR) in the C-band. The sensor head is a BK7 prism coated with ITO/Au/ITO/TiO2 film. CPWR is excited on the film by the S-polarized components of an incident light. The narrow absorption peak of CPWR makes it possible to realize dual-wavelength differential intensity (DI) interrogation by using only one incident point. To implement DI interrogation, we used a DWDM component to sample the lights with central wavelengths of 1529.55 and 1561.42 nm from the lights reflected back by the sensor head. The intensities of the dual-wavelength lights varied oppositely within the measurement range of refractive index, thus, a steep slope was produced as the refractive index of the sample increased. The experimental results show that the sensitivity is 32.15/RIUs within the measurement range from 1.3584 to 1.3689 and the resolution reaches 9.3 × 10-6 RIUs. Benefiting from the single incident point scheme, the proposed sensor would be easier to calibrate in bio-chemical sensing applications. Moreover, this sensing method is expected to be applied to retro-reflecting SPR sensors with tapered fiber tip to achieve better resolution than wavelength interrogation.

Highly sensitive differential fiber-optic SPR sensor in telecom band.

We proposed a differential fiber-optic SPR remote sensor with ultra-high sensitivity in telecom band. The working band of the sensor is designed as the C-band which is the low loss band of optical fiber communication aiming to improve the sensitivity and enable the capability of remote monitoring. The sensor head is a BK7 prism coated with Au/TiO2 films, enabling two channels for differential intensity interrogation. The intensities of the reflected lights through the channels vary oppositely within the measurement range of refractive index. Due to the sharp dip of angular resonant response in the C-band, the differential signal produces a steep slope as the refractive index of the sample varies, thus higher sensitivity is expected in a narrow measurement range. According to the results, the sensitivity is as high as 456 V/RIUs within the narrow measurement range of 1.3×10-2 RIUs and the resolution reaches to 6×10-6 RIUs. The measurement range can be tuned conveniently by adjusting the thickness of TiO2 film and can be expanded by increasing the number of sensing channels, which provides great convenience for the application of biosensor requiring high sensitivity.

Effect of Structural Supermodulation on Superconductivity in Trilayer Cuprate Bi_{2}Sr_{2}Ca_{2}Cu_{3}O_{10+δ}.

We investigate the spatial and doping evolutions of the superconducting properties of trilayer cuprate Bi_{2}Sr_{2}Ca_{2}Cu_{3}O_{10+δ} by using scanning tunneling microscopy and spectroscopy. Both the superconducting coherence peak and gap size exhibit periodic variations with structural supermodulation, but the effect is much more pronounced in the underdoped regime than at optimal doping. Moreover, a new type of tunneling spectrum characterized by two superconducting gaps emerges with increasing doping, and the two-gap features also correlate with the supermodulation. We propose that the interaction between the inequivalent outer and inner CuO_{2} planes is responsible for these novel features that are unique to trilayer cuprates.

Anomalous Doping Evolution of Superconductivity and Quasiparticle Interference in Bi_{2}Sr_{2}Ca_{2}Cu_{3}O_{10+δ} Trilayer Cuprates.

We use scanning tunneling microscopy to investigate Bi_{2}Sr_{2}Ca_{2}Cu_{3}O_{10+δ} trilayer cuprates from the optimally doped to overdoped regime. We find that the two distinct superconducting gaps from the inner and outer CuO_{2} planes both decrease rapidly with doping, in sharp contrast to the nearly constant T_{C}. Spectroscopic imaging reveals the absence of quasiparticle interference in the antinodal region of overdoped samples, showing an opposite trend to that in single- and double-layer compounds. We propose that the existence of two types of inequivalent CuO_{2} planes and the intricate interaction between them are responsible for these anomalies in trilayer cuprates.

Simultaneous enhancement of photoluminescence and afterglow luminescence through Bi3+ co-doping in the Sr3Al2O5Cl2:Eu2+ phosphor.

In this work, the Sr3Al2O5Cl2:Eu2+ and Sr3Al2O5Cl2:Eu2+,Bi3+ phosphors are synthesized by high temperature solid state reactions. Various characterization techniques, such as X-ray diffraction (XRD), Rietveld refinement, photoluminescence (PL) spectroscopy, afterglow spectroscopy, decay curves and thermoluminescence (TL) spectroscopy, are used to examine the phase purity and PL properties of all samples. The XRD results show that all samples belong to the targeted orthorhombic Sr3Al2O5Cl2 phase with the space group of P212121. Upon excitation with UV light, Eu2+-related reddish photoemission and afterglow luminescence are observed in the Sr3Al2O5Cl2:Eu2+ samples. More remarkably, we find that co-doping with Bi3+ ions can enhance the Eu2+-related photoemission and afterglow intensity as well the afterglow duration. For the optimal Sr3Al2O5Cl2:Eu2+,Bi3+ sample, the afterglow luminescence can continue for nearly 550 min in the dark, which is almost 3-fold the duration of the afterglow luminescence of the optimal Sr3Al2O5Cl2:Eu2+ sample. The TL spectra reveal that co-doping with Bi3+ ions can enhance the defect population that corresponds to trap depths at 63 °C, 75 °C and 150 °C, of which the former two trap depths may help to improve the Eu2+-related luminescence in addition to the afterglow property. Due to an increase in the trap concentration, there is an increase in the re-trapping possibility for the released carriers. This work not only achieves enhanced afterglow luminescence of the Sr3Al2O5Cl2:Eu2+ phosphor by co-doping with the non-rare earth (RE) Bi3+ ions, but also provides new insights into the design of RE and non-RE related enhanced afterglow photonic materials for the future.

A Polarization-Independent Fiber-Optic SPR Sensor.

Fiber-optic surface plasmon resonance (SPR) sensors possess the advantages of small size, flexible, allowing for a smaller sample volume, easy to be integrated, and high sensitivity. They have been intensively developed in recent decades. However, the polarizing nature of the surface plasmon waves (SPWs) always hinders the acquisition of SPR spectrum with high signal-noise ratio in wavelength modulation unless a polarizer is employed. The addition of polarizer complicates the system and reduces the degree of compactness. In this work, we propose and demonstrate a novel, polarization-independent fiber-optic SPR sensor based on a BK7 bi-prism with two incident planes orthogonal to each other. In the bi-prism, TM-polarized components of non-polarized incident lights excite SPWs on the first sensing channel, meanwhile the TE components and the remaining TM components are reflected, then the reflected TE components serve as TM components of incident lights for the second sensing channel to excite SPWs. Simulations show the proposed SPR structure permit us to completely eliminate the polarization dependence of the plasmon excitation. Experimental results agree well with the simulations. This kind of devices can be considered an excellent option for development of simple and compact SPR chemical sensors.

Modification and Wettability Study ITO Glass Coated with ZnO Film by Electrochemical Deposition and Hydrothermal Deposition.

ITO glass is a substrate often utilized to construct various IT devices and sensors, favored for its excellent characteristics such as rapid electron transfer kinetics, non-toxicity, chemical stability, and high electron transmission. In this paper, film with ZnO-modified nanostructures on ITO glass was fabricated by both electrochemical deposition and hydrothermal deposition, respectively. The ZnO film as-deposited was then modified by surface modification reagent (FOTMS) to obtain a hydrophobic surface. SEM, XRD, and ZYGO were used to characterize their properties. The contact angles were then measured to characterize and compare the wettability of non-modified ITO glass and ITO glass modified by zinc oxide films.

The Next-Generation Probiotic E. coli 1917-pSK18a-MT Ameliorates Cadmium-Induced Liver Injury by Surface Display of Metallothionein and Modulation of Gut Microbiota.

Cadmium (Cd) is recognized as being linked to several liver diseases. Currently, due to the limited spectrum of drugs available for the treatment of Cd intoxication, developing and designing antidotes with superior detoxification capacity and revealing their underlying mechanisms remains a major challenge. Therefore, we developed the first next-generation probiotic E. coli 1917-pSK18a-MT that delivers metallothionein (MT) to overcome Cd-induced liver injury in C57BL/6 mice by utilizing bacterial surface display technology. The results demonstrate that E. coli 1917-pSK18a-MT could efficiently express MT without altering the growth and probiotic properties of the strain. Moreover, we found that E. coli 1917-pSK18a-MT ameliorated Cd contamination-induced hepatic steatosis, inflammatory cell infiltration, and liver fibrosis by decreasing the expression of aminotransferases along with inflammatory factors. Activation of the Nrf2-Keap1 signaling pathway also further illustrated the hepatoprotective effects of the engineered bacteria. Finally, we showed that E. coli 1917-pSK18a-MT improved the colonic barrier function impaired by Cd induction and ameliorated intestinal flora dysbiosis in Cd-poisoned mice by increasing the relative abundance of the Verrucomicrobiota. These data revealed that the combination of E. coli 1917 and MT both alleviated Cd-induced liver injury to a greater extent and restored the integrity of colonic epithelial tissues and bacterial dysbiosis.

Emergent normal fluid in the superconducting ground state of overdoped cuprates.

The microscopic mechanism for the disappearance of superconductivity in overdoped cuprates is still under heated debate. Here we use scanning tunneling spectroscopy to investigate the evolution of quasiparticle interference phenomenon in Bi2Sr2CuO6+δ over a wide range of hole densities. We find that when the system enters the overdoped regime, a peculiar quasiparticle interference wavevector with arc-like pattern starts to emerge even at zero bias, and its intensity grows with increasing doping level. Its energy dispersion is incompatible with the octet model for d-wave superconductivity, but is highly consistent with the scattering interference of gapless normal carriers. The gapless quasiparticles are mainly located near the antinodes and are independent of temperature, consistent with the disorder scattering mechanism. We propose that a branch of normal fluid emerges from the pair-breaking scattering between flat antinodal bands in the quantum ground state, which is the primary cause for the reduction of superfluid density and suppression of superconductivity in overdoped cuprates.

Correlating the charge-transfer gap to the maximum transition temperature in Bi2Sr2Can-1CunO2n+4+δ.

As the number of CuO2 layers, n, in each unit cell of a cuprate family increases, the maximum transition temperature (Tc,max) exhibits a universal bell-shaped curve with a peak at n = 3. The microscopic mechanism of this trend remains elusive. In this study, we used advanced electron microscopy to image the atomic structure of cuprates in the Bi2Sr2Can-1CunO2n+4+δ family with 1 ≤ n ≤ 9; the evolution of the charge-transfer gap size (Δ) with n can be measured simultaneously. We determined that the n dependence of Δ follows an inverted bell-shaped curve with the minimum Δ value at n = 3. The correlation between Δ, n, and Tc,max may clarify the origin of superconductivity in cuprates.

Engineered probiotics Clostridium butyricum-pMTL007-GLP-1 improves blood pressure via producing GLP-1 and modulating gut microbiota in spontaneous hypertension rat models.

Hypertension is a significant risk factor of cardiovascular diseases (CVDs) with high prevalence worldwide, the current treatment has multiple adverse effects and requires continuous administration. The glucagon-like peptide-1 receptor (GLP-1R) agonists have shown great potential in treating diabetes mellitus, neurodegenerative diseases, obesity and hypertension. Butyric acid is a potential target in treating hypertension. Yet, the application of GLP-1 analogue and butyric acid in reducing blood pressure and reversing ventricular hypertrophy remains untapped. In this study, we combined the therapeutic capability of GLP-1 and butyric acid by transforming Clostridium butyricum (CB) with recombinant plasmid pMTL007 encoded with hGLP gene to construct the engineered probiotics Clostridium butyricum-pMTL007-GLP-1 (CB-GLP-1). We used spontaneous hypertensive rat (SHR) models to evaluate the positive effect of this strain in treating hypertension. The results revealed that the intragastric administration of CB-GLP-1 had markedly reduced blood pressure and improved cardiac marker ACE2, AT2R, AT1R, ANP, BNP, ß-MHC, α-SMA and activating AMPK/mTOR/p70S6K/4EBP1 signalling pathway. The high-throughput sequencing further demonstrated that CB-GLP-1 treatments significantly improved the dysbiosis in the SHR rats via downregulating the relative abundance of Porphyromonadaceae at the family level and upregulating Lactobacillus at the genus level. Hence, we concluded that the CB-GLP-1 greatly improves blood pressure and cardiomegaly by restoring the gut microbiome and reducing ventricular hypertrophy in rat models. This is the first time using engineered CB in treating hypertension, which provides a new idea for the clinical treatment of hypertension.

Engineered Bacteria EcN-MT Alleviate Liver Injury in Cadmium-Exposed Mice via its Probiotics Characteristics and Expressing of Metallothionein.

Cadmium (Cd) exposure is a widespread problem in many parts of the world, but effective means to treat Cd exposure is still lacking. Hence, an engineered strain expressing metallothionein (MT) named Escherichia coli Nissle 1917 (EcN)-MT was constructed, and its potential in the treatment of Cd exposure was evaluated. The in vitro studies showed that metallothionein expressed by EcN-MT could significantly bind Cd. Further, the in vivo results indicated that EcN-MT strain could reduce 26.3% Cd in the liver and increase 24.7% Cd in the feces, which greatly decreased malondialdehyde (MDA) levels and increased catalase (CAT), glutathione (GSH), and superoxide dismutase (SOD) levels in liver, and reduced the expression of toll-like receptor4 (TLR4), nuclear factor-κB (NF-κB), the myeloid differentiation factor 88 (Myd88) andincreased B-cell lymphoma 2 (Bcl-2)/Bcl-2-Associated X (Bax). Moreover, high throughput sequencing results indicated that EcN-MT strain greatly enhanced the beneficial bacteria of Ruminococcaceae, Lactobacillaceae, Akkermansia, Muribaculaceae, Lachnospiraceae, Dubosiella and restored the disturbed microbial ecology to the normal level. Therefore, the high Cd binding capacity of the expressed metallothionein, together with the beneficial characteristics of the host bacteria EcN, makes EcN-MT a sound reagent for the treatment of subchronic Cd exposure-induced liver injury.

Carbonaceous aerosol characteristics in outdoor and indoor environments of Nanchang, China, during summer 2009.

A study of carbonaceous aerosol was initiated in Nanchang, a city in eastern China, for the first time. Daily and diurnal (daytime and nighttime) PM2.5 (particulate matter with aerodynamic diameter < or =2.5 microm) samples were collected at an outdoor site and in three different indoor environments (common office, special printing and copying office, and student dormitory) in a campus of Nanchang University during summer 2009 (5-20 June). Daily PM10 (particulate matter with aerodynamic diameter < or =10 microm) samples were collected only at the outdoor site, whereas PM2.5 samples were collected at both indoor and outdoor sites. Loaded PM2.5 and PM10 samples were analyzed for organic and elemental carbon (OC, EC) by thermal/optical reflectance following the Interagency Monitoring of Protected Visual Environments-Advanced (IMPROVE-A) protocol. Ambient mass concentrations of PM10 and PM2.5 in Nanchang were compared with the air quality standards in China and the United States, and revealed high air pollution levels in Nanchang. PM2.5 accounted for about 70% of PM10, but the ratio of OC and EC in PM2.5 to that in PM10 was higher than 80%, which indicated that OC and EC were mainly distributed in the fine particles. The variations of carbonaceous aerosol between daytime and nighttime indicated that OC was released and formed more rapidly in daytime than in nighttime. OC/EC ratios were used to quantify secondary organic carbon (SOC). The differences in SOC and SOC/OC between daytime and nighttime were useful in interpreting the secondary formation mechanism. The results of (1) OC and EC contributions to PM2.5 at indoor sites and the outdoor site; (2) indoor-outdoor correlation of OC and EC; (3) OC-EC correlation; and (4) relative contributions of indoor and outdoor sources to indoor carbonaceous aerosol indicated that OC indoor sources existed in indoor sites, with the highest OC emissions in I2 (the special printing and copying office), and that indoor EC originated from outdoor sources. The distributions of eight carbon fractions in emissions from the printer and copier showed obviously high OC1 (>20%) and OC2 (approximately 30%), and obviously low EC1-OP (a pyrolyzed carbon fraction) (<10%), when compared with other sources.

Intraband hot-electron photoluminescence of a silver nanowire-coupled gold film via high-order gap plasmons.

We report a strong one-photon photoluminescence (PL) behavior of a silver nanowire directly coupled gold film. The PL peak position of the silver nanowire-coupled gold film deviates from the intrinsic interband transition of gold materials and is not sensitive to the diameter change of the silver nanowire. We attribute this strong PL behavior to the intraband transition of hot electrons dominated by high-order gap plasmons, which are excited in the ultra-small gap formed by an ultra-thin polyvinyl pyrrolidone (PVP) layer coated on the silver nanowire. The results show that the energy required for the strong PL of the heterogeneous system mainly comes from the gold film, acting as an incident energy absorber enhanced by the high-order gap plasmons, while the silver nanowire acts an efficient incident energy focusing antenna. In situ Raman scattering spectra and time-resolved PL intensity integral curves were used to record the carbonization and disappearance process of PVP. The understanding of the PL behavior of the silver nanowire directly coupled gold film proves the universality of plasmon-modulated PL theory and is also of great significance to improve the generation and utilization efficiency of hot electrons with high-order gap plasmons in the fields of catalysis and incident energy capture.

Potential hazardous effects of printing room PM2.5 exposure include promotion of lung inflammation and subsequent injury.

There have been few studies investigating the potential effects of indoor sources of particulate matter on human health. In this study, the effect of different concentrations of fine particulate matter (PM2.5) collected from a printing room on lung health was examined using cultured cells and a mouse model. Further, the mechanism of lung injury was examined. The results indicated that PM2.5 significantly enhanced malondialdehyde activity (P<0.05), decreased superoxide dismutase activity (P<0.05), upregulated the expression of pro­inflammatory factors including interleukin (IL)­1ß, tumor necrosis factor­, IL­6 and downregulated the expression of the inflammatory factor IL­2 (P<0.05). Western blot analysis indicated that PM2.5 significantly enhanced expression of phosphorylated (p)­ERK relative to total ERK, cyclooxygenase­2, p­anti­nuclear­factor­κB (p­NF­κB) relative to NF­κB, transforming growth factor­ß1 and Bax relative to Bcl­2 in inflammation (P<0.05), fibrosis and apoptosis signaling pathways. Furthermore, the results revealed that exposure was associated with an increased abundance of pathogens including Burkholderiales, Coriobacteriia, and Betaproteobacteria in in the lungs. In conclusion, exposure to PM2.5 from a printing room significantly increased inflammation, fibrosis, apoptosis and the abundance of pathogenic bacteria, indicating that exposure is potential threat to individuals who spend a significant amount of time in printing rooms.

Intestinal microbiota regulates anti-tumor effect of disulfiram combined with Cu2+ in a mice model.

BACKGROUND: A growing number of studies show that intestinal microbiota affect the therapeutic effects of antineoplastic agents. Disulfiram (tetraethylthiuram disulfide, DSF) is an old alcohol-aversion drug that has been shown to be effective against various types of cancers in preclinical studies, while few studies are carried out to explore its mechanism. METHODS: A mice model of melanoma xenograft was generated and treated with antibiotics (Abx), disulfiram/copper (DSF/Cu2+ ), Abx + DSF/Cu2+ , and the tumor volume and survival curve were observed. Hematoxylin-eosin (HE) staining and western blotting (WB) were used to observe the protein changes related to cell morphology, inflammation, and apoptosis in tumor tissues. Quantitative real time polymerase chain reaction (qPCR) was used to detect the expression of pro-inflammatory cytokines in tumors. High-throughput sequencing was used to detect the effects of Abx and DSF/Cu2+ on intestinal microbiota. RESULTS: The DSF/Cu2+ and Abx + DSF/Cu2+ markedly delayed tumor progression and prolonged mice survival, of which the combination of Abx and DSF/Cu2+ possessed the best anti-tumor effect. Abx + DSF/Cu2+ significantly reduced the pro-inflammatory cytokines Interleukin-1ß (IL-1ß), IL-6 and tumor necrosis factor α (TNF-α) in tumors, and significantly reduced the expression of phosphorylated-protein kinase B (p-AKT)/protein kinase B (AKT), toll-like receptors 4 (TLR-4), and phosphorylated- nuclear factor kappa-B (p-NFκB)/NFκB in tumors. Moreover our high-throughput sequencing first indicated that the sound anti-cancer effect of Abx + DSF/Cu2+ had a strong connection with the increased abundance of intestinal beneficial bacteria Akkermansia, as well as the reduced abundance of opportunistic pathogenic bacteria Campylobacterales, Helicobacteraceae, and Coriobacteriaceae. CONCLUSIONS: The disturbed intestinal microbiota (increased abundance of opportunistic pathogens Campylobacterales, Helicobacteraceae, and Coriobacteriaceae) and the over-activated TLR4/NF-κB signaling pathway in tumor tissues deteriorated the cancer development, and the using of antibiotics is benefit to enhance the therapeutic effect of DSF on tumors via inhibiting the growth of opportunistic pathogenic bacteria.

Characteristics of indoor/outdoor PM2.5 and elemental components in generic urban, roadside and industrial plant areas of Guangzhou City, China.

Quantitative information on mass concentrations and other characteristics, such as spatial distribution, seasonal variation, indoor/outdoor (I/O) ratio, correlations and sources, of indoor and outdoor PM2.5 and elemental components in Guangzhou City were provided. Mass concentration of PM2.5 and elemental components were determined by standard weight method and proton-induced X-ray emission (PIXE) method. 18 elements were detected, the results showed positive results. Average indoor and outdoor PM2.5 concentrations in nine sites were in the range of 67.7-74.5 microg/m3 for summer period, and 109.9-123.7 microg/m3 for winter period, respectively. The sum of 18 elements average concentrations were 5362.6-5533.4 ng/m3 for summer period, and 8416.8-8900.6 ng/m3 for winter period, respectively. Average concentrations of PM2.5 and element components showed obvious spatial characteristic, that the concentrations in roadside area and in industrial plant area were higher than those in generic urban area. An obvious seasonal variation characteristic was found for PM2.5 and elemental components, that the concentrations in winter were higher than that in summer. The I/O ratio of PM2.5 and some elemental components presented larger than 1 sometimes. According to indoor/outdoor correlation of PM2.5 and element concentrations, it was found that there were often good relationships between indoor and outdoor concentrations. Enrichment factors were calculated to evaluate anthropogenic versus natural elements sources.

A novel gas ionization sensor using Pd nanoparticle-capped ZnO.

A novel gas ionization sensor using Pd nanoparticle-capped ZnO (Pd/ZnO) nanorods as the anode is proposed. The Pd/ZnO nanorod-based sensors, compared with the bare ZnO nanorod, show lower breakdown voltage for the detected gases with good sensitivity and selectivity. Moreover, the sensors exhibit stable performance after more than 200 tests for both inert and active gases. The simple, low-cost, Pd/ZnO nanorod-based field-ionization gas sensors presented in this study have potential applications in the field of gas sensor devices.