Self-Trapped Exciton Emission in Highly Polar 0D Hybrid Ammonium/Hydronium-Based Perovskites Triggered by Antimony Doping.

Various monovalent cations are employed to construct metal halide perovskites with various structures and functionalities. However, perovskites based on highly polar A-site cations have seldom been reported. Here, a novel hybrid 0D (NH4)x(OH3)3-xInCl6 perovskite with highly polar hydronium OH3+ cations is introduced in this study. Upon doping with Sb3+, hybrid 0D (NH4)x(OH3)3-xInCl6 single crystals exhibited highly efficient broadband yellowish-green (550 nm) and red (630 nm) dual emissions with a PLQY of 86%. The dual emission arises due to Sb3+ occupying two sites within the crystal lattice that possess different polarization environments, leading to distinct Stokes shift energies. The study revealed that lattice polarity plays a significant role in the self-trapped exciton emission of Sb3+-doped perovskites, contributing up to 25% of the Stokes shift energy for hybrid 0D (NH4)x(OH3)3-xInCl6:Sb3+ as a secondary source, in addition to the Jahn-Teller deformation. These findings highlight the potential of Sb3+-doped perovskites for achieving tunable broadband emission and underscore the importance of lattice polarity in determining the emission properties of perovskite materials.

Development of a label-free photoelectrochemical immunosensor for novel astrovirus detection.

Since 2017, an infectious goose gout disease characterized by urate precipitation in viscera, mainly caused by novel goose astrovirus (GoAstV) infection, has emerged in the main goose-producing region of China. The current challenge in managing goose gout disease is largely due to the absence of a rapid and efficient detection method for the GoAstV pathogen. Notably, the potential application of immunosensors in detecting GoAstV has not yet been explored. Herein, a label-free PEC immunosensor was fabricated by using purchased TiO2 as the photoactive material and antibody against GoAstV P2 proteins as the specific recognition element. First, we successfully expressed the capsid spike domain P2 protein of ORF2 from GoAstV CHSH01 by using the pET prokaryotic expression system. Meanwhile, the polyclonal antibody against GoAstV capsid P2 protein was produced by purified protein. To our knowledge, this is the first establishment and preliminary application of the label-free photoelectrochemical immunosensor method in the detection of AstV. The PEC immunosensor had a linear range of 1.83 fg mL-1 to 3.02 ng mL-1, and the limit of detection (LOD) was as low as 0.61 fg mL-1. This immunosensor exhibited high sensitivity, great specificity, and good stability in detecting GoAstV P2 proteins. To evaluate the practical application of the immunosensor in real-world sample detection, allantoic fluid from goose embryos was collected as test samples. The results indicated that of the eight positive samples, one false negative result was detected, while both negative samples were accurately detected, suggesting that the constructed PEC immunosensor had good applicability and practical application value, providing a platform for the qualitative detection of GoAstV.

Co-Delivery of Gemcitabine and Honokiol by Lipid Bilayer-Coated Mesoporous Silica Nanoparticles Enhances Pancreatic Cancer Therapy via Targeting Depletion of Tumor Stroma.

Syndecan-1 (SDC1) modified lipid bilayer (LB)-coated mesoporous silica nanoparticles (MSN) to co-deliver gemcitabine (GEM) and honokiol (HNK) were prepared for the targeting treatment of pancreatic cancer. The encapsulation efficiencies of GEM and HNK in SDC1-LB-MSN-GEM/HNK were determined to be 60.3 ± 3.2% and 73.0 ± 1.1%. The targeting efficiency of SDC1-LB-MSN-GEM/HNK was investigated in BxPC-3 cells in vitro. The fluorescence intensity in the cells treated with SDC1-LB-MSN-Cou6 was 2-fold of LB-MSN-Cou6-treated cells, which was caused by SDC1/IGF1R-mediated endocytosis. As anticipated, its cytotoxicity was significantly increased. Furthermore, the mechanism was verified that SDC1-LB-MSN-HNK induced tumor cell apoptosis through the mitochondrial apoptosis pathway. Finally, the biodistribution, tumor growth inhibition, and preliminary safety studies were performed on BALB/c nude mice bearing BxPC-3 tumor models. The tumor growth inhibition index of SDC1-LB-MSN-GEM/HNK was 56.19%, which was 1.45-fold and 1.33-fold higher than that of the free GEM/HNK and LB-MSN-GEM/HNK treatment groups, respectively. As a result, SDC1-LB-MSN-GEM/HNK combined advantages of both GEM and HNK and simultaneously targeted and eliminated pancreatic cancerous and cancer-associated stromal cells. In summary, the present study demonstrated a new strategy of synergistic GEM and HNK to enhance the therapeutic effect of pancreatic cancer via the targeting depletion of tumor stroma.

P-Orbital Bismuth Single-Atom Catalyst for Highly Effective Oxygen Electroreduction in Quasi-Solid Zinc-Air Batteries.

P-block metals have gradually been utilized to synthesize non-noble-metal catalysts for oxygen reduction reaction (ORR) due to the easily tunable localized p-orbitals and resulted versatile electronic structures. The high-density single-atom bismuth sites (Bi-NC) anchored onto nitrogen-doped three-dimensional porous carbon are proved to possess significant electrocatalytic ORR performance. Theoretical calculations unveil positively charged bismuth centers prominently improved the adsorption capacity of N-doped carbon to O2 . The p orbitals of Bi sites within Bi-NC easily generate hybrid states with p orbitals of O2 , thus promoting charge transfer and ultimately reducing the energy barrier of ORR. Benefiting from p-orbital electrons regulation of bismuth atoms, Bi-NC exhibit ORR half-wave potential of 0.86 V (vs RHE). Additionally, both liquid and quasi-solid zinc-air batteries with Bi-NC as air-cathodes achieve higher power density and specific capacity than 20 wt% Pt/C, and comparable stability and round-trip efficiency with 20 wt% Pt/C. The discovery sheds light on the theoretical and practical guidance for p-block metallic single-atom catalysts.

Comparative transcriptomics and co-expression networks reveal cultivar-specific molecular signatures associated with reproductive-stage cold stress in rice.

KEY MESSAGE: The resistance of Huaidao5 results from the high constitutive expression of tolerance genes, while that of Huaidao9 is due to the cold-induced resistance in flag leaves and panicles. The regulation mechanism of rice seedlings' cold tolerance is relatively clear, and knowledge of its underlying mechanisms at the reproductive stage is limited. We performed differential expression and co-expression network analyses to transcriptomes from panicle and flag leaf tissues of a cold-tolerant cultivar (Huaidao5), and a sensitive cultivar (Huaidao9), under reproductive-stage cold stress. The results revealed that the expression levels of genes in stress-related pathways such as MAPK signaling pathway, diterpenoid biosynthesis, glutathione metabolism, plant-pathogen interaction and plant hormone signal transduction were constitutively highly expressed in Huaidao5, especially in panicles. Moreover, the Hudaidao5's panicle sample-specific (under cold) module contained some genes related to rice yield, such as GW5L, GGC2, SG1 and CTPS1. However, the resistance of Huaidao9 was derived from the induced resistance to cold in flag leaves and panicles. In the flag leaves, the responses included a series of stress response and signal transduction, while in the panicles nitrogen metabolism was severely affected, especially 66 endosperm-specific genes. Through integrating differential expression with co-expression networks, we predicted 161 candidate genes (79 cold-responsive genes common to both cultivars and 82 cold-tolerance genes associated with differences in cold tolerance between cultivars) potentially affecting cold response/tolerance, among which 85 (52.80%) were known to be cold-related genes. Moreover, 52 (65.82%) cold-responsive genes (e.g., TIFY11C, LSK1 and LPA) could be confirmed by previous transcriptome studies and 72 (87.80%) cold-tolerance genes (e.g., APX5, OsFbox17 and OsSTA109) were located within QTLs associated with cold tolerance. This study provides an efficient strategy for further discovery of mechanisms of cold tolerance in rice.

Long-term improvement of sediment in situ restoration and REDOX characteristics by Vallisneria natans coupling with carbon fiber.

China is conducting ecological restoration work in urban water bodies. Under anoxic and anaerobic conditions, pollutants transform and produce odorous and black substances, deteriorating the water quality, which is a significant problem in urban water bodies. Vallisneria natans has received widespread attention for its applications in water treatment and restoration. However, the efficiency by which V. natans reduces water pollution and allows sediment remediation requires further improvement. Therefore, in this study, we investigated the effect of V. natans coupled with carbon fiber on the restoration of water bodies and sediment compared with the control group that grew V. natans without carbon fiber. The oxidation-reduction potential (ORP) was selected as the main evaluation index for the water and sediment. Dissolved oxygen in the water and total organic carbon and total nitrogen (TN) in the sediment were also evaluated. V. natans coupled with carbon fiber significantly increased the ORP; that of surface sediment increased by 50 % and that of the water body increased by 60 % compared with the sediment without any bioremediation. Chemical oxygen demand, total phosphorous, and TN in water decreased by 61.2 %, 22.9 %, and 48.3 %, respectively. These results indicate that planting V. natans with carbon fiber can reduce pollutants in water (including humus) and sediments, effectively improving ORP in water and sediment.

Improved the in-situ remediation effect of benthic microbial electrochemical system by optimizing the anode structure.

Six 60-L benthic microbial electrochemical systems (BMESs) were built for the bioremediation of river sediment. Carbon mesh anodes with honeycomb-structure supports were compared with horizontal anodes, and the system was tested using different cover depths and anode densities. The pollutant removal, electricity generation, and electrochemistry of the six BMES with different anodes was examined using the Ashi River (Harbin, China) as a case study. Total organic carbon and total nitrogen removal from sediments in BMES with Honeycomb-structure anodes were 20-30% and 20-33% higher for the other reactors. The maximum power densities of 43.2 mW m-2 was obtained in BMES. The maximum power densities in BMES with honeycomb-structure anodes were 10-40% higher than that of BMESs with horizontal anode reactors.

Zero-Dimensional Organic-Inorganic Hybrid Copper-Based Halides with Highly Efficient Orange-Red Emission.

Lead-free metal halides are promising luminescent materials with low non-toxicity, tunable emission, and high luminescence quantum yield (PLQY). The development of red light-emitting materials with high PLQY to meet the color coordinate requirements for light-emitting diode (LED) lighting and wide color gamut displays remains a major scientific challenge. Herein, novel lead-free copper-based halide materials are reported. PEA4 Cu4 I4 is an efficient orange-red broad emission with a highest PLQY of 73.6%. All three materials, namely, those of ((R)-(+)-α-PEA)4 Cu4 I4 , ((S)-(-)-α-PEA)4 Cu4 I4 , and (ß-PEA)4 Cu4 I4 with zero-dimensional structures have large exciton binding energies and Huang-Rhys factors, thus causing efficient self-trapped exciton emissions. A prototypical orange-red LED device is fabricated successfully that demonstrates the potential of copper-based halide materials in lighting and display applications.

Identification of a novel plasmid-mediated tigecycline resistance-related gene, tet(Y), in Acinetobacter baumannii.

OBJECTIVES: To characterize a novel plasmid-mediated tigecycline resistance-related gene, tet(Y), in a clinical Acinetobacter baumannii isolate from China. METHODS: The tet(Y)-encoded tigecycline-resistant A. baumannii 2016GDAB1 was screened through antimicrobial susceptibility testing and WGS. The function of tet(Y) was verified by complementation of tet(Y). The plasmid transferability and stability were detected via plasmid conjugation and in vitro bacterial passaging. The 3D structure of Tet(Y) was predicted and docked using tFold and AutoDock Vina. RESULTS: The tigecycline-resistant A. baumannii 2016GDAB1 was isolated from bronchoalveolar lavage fluid of a patient with hospital-acquired pneumonia. However, this strain did not harbour any common tigecycline resistance genes, determinants or mutations. 2016GDAB1 belongs to the non-epidemic clone ST355 (Oxford scheme), which has been mainly reported in animals. The tet(Y) gene was located on a 72 156 bp plasmid and genomic environment analysis revealed that Tn5393 may play a role in tet(Y) transmission, whereas phylogenetic analysis indicated the origin of tet(Y) as from Aeromonas. Overexpression of tet(Y) resulted in a 2- to 4-fold increase in tigecycline MIC. Introduction of the tet(Y)-harbouring plasmid p2016GDAB1 via electroporation resulted in a 16-fold increase in tigecycline MIC but failed to transfer into the tigecycline-susceptible A. baumannii recipient via conjugation. Isolates carrying the tet(Y) gene were vulnerable to tigecycline pressure and exhibited decreased susceptibility to tigecycline. A tet(Y)-carrying plasmid was stably maintained in the host strains. CONCLUSIONS: This study identified the tigecycline resistance-related gene tet(Y) in A. baumannii. This gene conferred an increased tigecycline MIC and the transposable element Tn5393 may play a role in its transmission across isolates.

Considering the flanking region variants of nonbinary SNP and phenotype-informative SNP to constitute 30 microhaplotype loci for increasing the discriminative ability of forensic applications.

The flanking region variants of nonbinary SNPs and phenotype-informative SNPs (piSNPs) have been observed, which may greatly improve the discriminative ability after constituting microhaplotype. In this study, 30 microhaplotype loci based on the nonbinary SNPs and piSNPs (shown to be related to phenotypes such as hair and eye color) were selected. Genotyping were conducted on 100 unrelated northern Han Chinese, and the 26 populations from the 1000 Genome Project were also included for comparison of populations differentiation. The simulated study was conducted for evaluating the efficiency of kinship testing. These 30 microhaplotype loci we selected had good polymorphism, with a mean effective number of alleles (Ae) of 3.46. The average Ae increase was 1.27 compared with the target SNPs. The populations from the five regions worldwide could also be distinguished using these loci. The results of kinship testing showed that these microhaplotype loci had the similar ability as 15 STR loci of AmpFlSTRR IdentifilerR PCR Amplification Kit to identify the biological parent and a stronger ability to exclude the nonbiological parents. So, these 30 microhaplotype loci may be multifunctional for forensic application, including the ability of personal identification and kinship testing equivalent to 15 STR loci, and the power of ancestry inference for distinguishing the main intercontinental population. Moreover, our selected phenotypic microhaplotype loci may theoretically have phenotype prediction capabilities. But the phenotype prediction efficiency of these phenotypic microhaplotype loci may be worse than that of piSNPs and the detailed prediction accuracy of different populations needs to be further studied.

Clinical and microbiological characteristics of adults with hospital-acquired pneumonia: a 10-year prospective observational study in China.

Hospital-acquired pneumonia (HAP) is a significant nosocomial infection; data on the distribution and antimicrobial resistance profiles of HAP in China are limited. We included 2827 adult patients with HAP from the Chinese Antimicrobial Resistance Surveillance of Nosocomial Infections network admitted in 15 Chinese teaching hospitals between 2007 and 2016. Clinical data and antimicrobial susceptibility of isolated pathogens were obtained from the medical records and central laboratory, respectively. Multivariable logistic regression was performed to determine the risk factors for mortality and multidrug resistance (MDR). A total of 386 (13.7%) patients died in the hospital, while 1181 (41.8%) developed ventilator-associated pneumonia (VAP). Active immunosuppressant therapy (OR 1.915 (95% CI 1.475-2.487)), solid tumor (OR 1.860 (95% CI 1.410-2.452)), coma (OR 1.783 (95% CI 1.364-2.333)), clinical pulmonary infection score ≥7 (OR 1.743 (95% CI 1.373-2.212)), intensive care unit stay (OR 1.652 (95% CI 1.292-2.111)), age ≥65 years (OR 1.621 (95% CI 1.282-2.049)), and tracheal cannula insertion (OR 1.613 (95% CI 1.169-2.224)) were independent risk factors for in-hospital mortality. Liver cirrhosis (OR 3.120 (95% CI 1.436-6.780)) and six other variables were independent predictors of MDR. Acinetobacter baumannii (25.6%), Pseudomonas aeruginosa (20.1%), Klebsiella pneumoniae (15.4%), and Staphylococcus aureus (12.6%) were the most common pathogens (MDR prevalence 64.9%). Isolates from VAP patients showed more A. baumannii and less K. pneumoniae and E. coli strains (p < 0.001, respectively) than those from patients without VAP. The proportion of methicillin-resistant S. aureus strains decreased; that of carbapenem-resistant A. baumannii and Enterobacterales strains increased. There had been changes in the antibiotic resistance profiles of HAP pathogens in China. Risk factors for mortality and MDR are important for the selection of antimicrobials for HAP in China.

A photoelectrochemical aptasensor of ciprofloxacin based on Bi24O31Cl10/BiOCl heterojunction.

A photoelectrochemical (PEC) aptasensor was designed and constructed by Bi24O31Cl10/BiOCl heterojunction as a photoelectric active material for realizing the determination of trace ciprofloxacin (CIP) in water. Compared with Bi24O31Cl10, Bi24O31Cl10/BiOCl heterojunction possessed the improvement of light harvesting and the enhancement of photocurrent signal. The formation of heterojunction between Bi24O31Cl10 and BiOCl can accelerate the transportation efficiency and inhibit the recombination rate of photoinduced carriers. Based on the excellent PEC performance, CIP aptamer was introduced on the modified Bi24O31Cl10/BiOCl/indium tin oxide (ITO) electrode for fabricating a PEC aptasensor. Owing to the combination between aptamer and CIP, CIP-aptamer complex can block the transfer of charge, leading to the reduction of photocurrent response. The PEC aptasensor possessed high sensitivity with a wide detection range (5.0~1.0 × 104 ng L-1) and a low detection limit (1.67 ng L-1, S/N = 3). The PEC aptasensor with good selectivity and reproducibility has been applied to the determination of CIP in water.

Evaluation of the in vitro activity of new polymyxin B analogue SPR206 against clinical MDR, colistin-resistant and tigecycline-resistant Gram-negative bacilli.

BACKGROUND: SPR206 is a novel polymyxin analogue. Activity against clinical isolates is little documented. METHODS: A collection of 200 MDR, carbapenem-resistant, tigecycline-resistant, colistin-resistant and non-MDR clinical isolates of Acinetobacter baumannii, Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Enterobacter cloacae and Stenotrophomonas maltophilia was obtained from 50 centres across China (2016-17). All isolates were derived from respiratory tract, urine and blood samples. Strains were purposely selected on the basis of phenotypes, genotypes and specimen origins. MICs of SPR206 and other antimicrobials were determined. RESULTS: SPR206 was active against all bacteria tested except colistin-resistant isolates. The MIC50/90 values of SPR206 for colistin-resistant strains were comparable to known polymyxins (16/128 versus 8/128 mg/L). SPR206 exhibited potent activity against colistin-susceptible OXA-producing A. baumannii (MIC50/90 = 0.064/0.125 mg/L), NDM-producing Enterobacteriaceae (MIC50/90 = 0.125/0.25 mg/L) and KPC-2-producing Enterobacteriaceae (MIC50/90 = 0.125/0.5 mg/L). In fact, SPR206 was the most potent agent tested, with 2- to 4-fold lower MICs than colistin and polymyxin B for A. baumannii, P. aeruginosa and Enterobacteriaceae. Additionally, MIC values of SPR206 (MIC50/90 = 0.064/0.125 mg/L) were 16- to 32-fold lower than those of tigecycline (MIC50/90 = 2/2 mg/L) for tigecycline-susceptible carbapenem-resistant A. baumannii. CONCLUSIONS: SPR206 showed good in vitro activity against MDR, tigecycline-resistant and non-MDR clinical isolates of Gram-negative pathogens. SPR206 also exhibited superior potency to colistin and polymyxin B, with 2- to 4-fold lower MIC50/90 values.

In vitro activity of the novel ß-lactamase inhibitor taniborbactam (VNRX-5133), in combination with cefepime or meropenem, against MDR Gram-negative bacterial isolates from China.

OBJECTIVES: To evaluate in vitro activity of the novel ß-lactamase boronate inhibitor taniborbactam (VNRX-5133) combined with cefepime or meropenem against 500 urinary Gram-negative bacilli. METHODS: Cefepime/taniborbactam and 14 comparators were tested by broth microdilution or agar dilution methods. A total of 450 Enterobacteriaceae and 50 Pseudomonas aeruginosa were selected from 2017 to 2019 based on different ß-lactamase-producing or resistance phenotypes. For carbapenem-non-susceptible isolates, the modified carbapenem inactivation method (mCIM), EDTA-CIM (eCIM) and amplification of carbapenemase genes were performed. For NDM-producing isolates and those with cefepime/taniborbactam MICs >8 mg/L, the MICs of meropenem/taniborbactam and/or mutations in PBP3 were investigated. RESULTS: Taniborbactam improved cefepime activity with the same efficiency as avibactam improved ceftazidime activity against 66 KPC-2 producers, 30 non-carbapenemase-producing carbapenem-non-susceptible Enterobacteriaceae and 28 meropenem-susceptible P. aeruginosa. However, cefepime/taniborbactam exhibited more potent activity than ceftazidime/avibactam against 56 ESBL-producing, 61 AmpC-producing, 32 ESBL and AmpC co-producing, 87 NDM-producing and 21 MBL-producing Enterobacteriaceae predicted by phenotypic mCIM and eCIM, 82 Enterobacteriaceae that were susceptible to all tested ß-lactams and 22 carbapenem-non-susceptible P. aeruginosa. A four-amino acid 'INYR' or 'YRIN' insertion, with or without a one/two-amino acid mutation in PBP3, may have caused cefepime/taniborbactam MICs >8 mg/L among 96.6% (28/29) of the NDM-5-producing Escherichia coli, which accounted for the majority of isolates with cefepime/taniborbactam MICs >8 mg/L (76.1%, 35/46). CONCLUSIONS: Taniborbactam's superior breadth of activity, when paired with cefepime or meropenem, suggests these ß-lactam/ß-lactamase inhibitor combinations could be promising candidates for treating urinary tract infections caused by ESBL and/or AmpC, KPC or NDM-producing Enterobacteriaceae or P. aeruginosa.

A photoelectrochemical aptasensor for sensitively monitoring chloramphenicol using plasmon-driven AgNP/BiOCl composites.

A photoelectrochemical (PEC) aptasensor based on silver nanoparticle/BiOCl (AgNP/BiOCl) composites was constructed for detecting chloramphenicol (CAP). The surface-plasmon resonance (SPR) effect of AgNPs can focus the incident light and promote the migration and separation of the photogenerated carriers of AgNP/BiOCl composites. As a result, the AgNP/BiOCl composites showed an enhanced PEC performance compared to that of pure BiOCl. A PEC CAP aptasensor was fabricated using AgNP/BiOCl composites as photoactive materials and a CAP aptamer as a recognition element. The PEC aptasensor exhibited a broad linear response range (0.2 pM-10 nM), a low limit of determination (0.08 pM), satisfactory selectivity, stability, and reproducibility to meet the practical analysis requirements. This work demonstrates that the PEC CAP aptasensor has a promising prospect in environmental assays.

Epitaxial Growth of Two-Dimensional Layered Transition-Metal Dichalcogenides: Growth Mechanism, Controllability, and Scalability.

Recently there have been many research breakthroughs in two-dimensional (2D) materials including graphene, boron nitride (h-BN), black phosphors (BPs), and transition-metal dichalcogenides (TMDCs). The unique electrical, optical, and thermal properties in 2D materials are associated with their strictly defined low dimensionalities. These materials provide a wide range of basic building blocks for next-generation electronics. The chemical vapor deposition (CVD) technique has shown great promise to generate high-quality TMDC layers with scalable size, controllable thickness, and excellent electronic properties suitable for both technological applications and fundamental sciences. The capability to precisely engineer 2D materials by chemical approaches has also given rise to fascinating new physics, which could lead to exciting new applications. In this Review, we introduce the latest development of TMDC synthesis by CVD approaches and provide further insight for the controllable and reliable synthesis of atomically thin TMDCs. Understanding of the vapor-phase growth mechanism of 2D TMDCs could benefit the formation of complicated heterostructures and novel artificial 2D lattices.

3D view image reconstruction in computational integral imaging using scale invariant feature transform and patch matching.

This paper realizes a computational integral imaging reconstruction method via scale invariant feature transform (SIFT) and patch matching to improve the visual quality of reconstructed 3D view images. To our knowledge, the 3D view images reconstructed from the elemental images suffer from artifacts, which leads to degradations in the visual quality. To prevent image degradation, in this paper, we use the correct regions obtained from the view images taken directly from the original object or use patch matching to replace the distorted regions. However, the initial matching regions could not meet our requirements owing to the limitations of the equipment and the inevitable shortcomings of the experimental operation. To solve these problems, we adopt SIFT descriptors and perspective transform to get the satisfying correct regions. We present the simulation and experimental results of the 3D view images and the evaluation of the quality of the corresponding images to test the performance of the proposed method. The simulation and experimental results indicate that the proposed method can significantly improve the visual quality of the 3D view images and verify the feasibility and effectiveness of the proposed method.

In vitro activities of Eravacycline against 336 isolates collected from 2012 to 2016 from 11 teaching hospitals in China.

BACKGROUND: In China multidrug-resistant bacteria pose a considerable threat to public health. Antimicrobial resistance has weakened the effectiveness of many medicines widely used today. Thus, discovering new antibacterial drugs is paramount in the effort to treat emerging drug-resistant bacteria. METHODS: Eravacycline, tigecycline and other clinical routine antibiotics were tested by reference broth micro-dilution method against 336 different strains collected from 11 teaching hospitals in China between 2012 and 2016. These isolates included Enterobacteriaceae, non-fermentative, Staphylococcus spp., Enterococcus, and a number of fastidious organisms. The strains involved in this study possess the most important drug resistance characteristics currently known in China. Drug resistant bacteria such as those producing extended spectrum ß-lactamases (ESBL) and carbapenemases (KPC-2 and NDM-1), and those exhibiting colistin resistance (mcr-1) and tigecycline were included in this study. Additionally, methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), ß-lactamase positive Haemophilus influenzae, and penicillin resistant Streptococcus pneumoniae (PRSP) were also included. RESULTS: Eravacycline exhibited good efficacy against all the strains tested, especially for organisms with ESBLs, carbapenemases, and mcr-1 gene compared with tigecycline and other antibiotics tested. The MIC values of eravacycline against carbapenemase producing Enterobacteriaceae and OXA-23-producing A. baumannii were much lower than the MIC values of other antibiotics. MRSA, VRE, ß-lactamase positive Haemophilus influenza, and PRSP were sensitive to eravacycline in every strain tested. Furthermore, in most strains tested, the MICs of eravacycline were two to four-fold lower than the MICs of tigecycline. CONCLUSIONS: Eravacycline has shown potent antibacterial activity against common and clinically important antibiotic-resistant pathogens. The MIC distribution of eravacycline was generally lower than that of tigecycline which demonstrates that this new drug is potentially more effective than the existing medications.

A self-powered photoelectrochemical aptamer probe for oxytetracycline based on the use of a NiO nanocrystal/g-C3N4 heterojunction.

A self-powered photoelectrochemical (PEC) aptamer probe is presented for the determination of oxytetracycline (OTC). The assay is based on the use of g-C3N4 and NiO nanocrystals (NCs) which form a heterojunction. The latter was prepared by two-step hydrothermal pyrolysis by using the ionic liquid 1-hydroxyethyl-3-methylimidazole chloride which functions as a morphological template to form NiO NCs. The heterojunction exhibits much better electronic conductivity, wider absorption range, higher electron-hole-separation productivity, and stronger photocurrent compared to plain g-C3N4. The heterojunction was adopted to construct a self-powered PEC aptamer probe for OTC detection. An OTC-binding aptamer was immobilized on the heterojunction and the probe was constructed. The aptamer on the probe binding with OTC can form steric hindrance for transmitting of electrons and cause the PEC signal change depending on the OTC concentration. The photocurrent decreases with increasing OTC concentration in the 0.01 to 100 nM concentration range and its detection limit is 4 pM (at S/N = 3). Graphical abstract Schematic representation of a self-powered photochemical aptamer probe. The probe performs enhanced ability for oxytetracycline (OTC) determination due to the formation of NiO nanocrystals/g-C3N4 (NiO NCs/g-C3N4) heterojunction and the specification recognition of the aptamer.

A composite prepared from BiOBr and gold nanoparticles with electron sink and hot-electron donor properties for photoelectrochemical aptasensing of tetracycline.

A photoelectrochemical (PEC) aptasensor is described for detecting tetracycline (TC). A gold nanoparticles/BiOBr (AuNPs/BiOBr) composite was prepared where the AuNPs play a key function in carrier transfer which is ascribed to the wavelength-dependent dual function as an electron sink and as a hot-electron donor. Due to this dual function, the composite exhibits a wide photo-response and high electron transfer efficiency. This results in enormously enhanced PEC response. The TC-aptamer was immobilized on an ITO modified with AuNPs/BiOBr via Au-S covalent bonding. The resulting PEC aptasensor possesses a wide linear range (1-104 ng L-1) and a low detection limit (0.35 ng L-1; at S/N = 3). Graphical abstractSchematic representation of a photoelectrochemical aptasensor for tetracycline based on the use of a AuNP/BiOBr composite with electron sink and hot-electron donor properties of the gold nanoparticles.