Progress in the preparation, application, and recycling of black phosphorus.

Black phosphorus nanosheets (BPNSs) are a new member of the nanomaterial family, and they have good development potential in electrochemistry, electronics, optoelectronics, environmental protection, biomedical, and other fields because of their bandgap width, high anisotropy, broad optical absorption, high carrier mobility and many other features. Although many articles have been published about the preparation and application of BPNSs, these aspects have not been elucidated, and we aimed to fill this knowledge gap in this review. First, we used VOSviewer software to sort out articles published in the past 5 years and drew a literature map, which allowed us to sort out the relationship between various studies related to BPNSs, and reflect on the research focus in recent years. Because BPNSs must be made from black phosphorus (BP), and BPNSs are a nano form of BP, the collation of the BP preparation scheme was also helpful for the related research on BPNSs. This paper introduces the preparation of bulk BP and BPNSs, analyzes and compares the advantages and disadvantages of each method, and points out the most promising methods in the future. Then, we propose improvement directions for this method. We also introduce the characterization of BPNSs and combine it with the subsequent photocatalytic application of BPNSs. As a new material, the effect of BPNSs on the environment is still unknown; thus, an end treatment scheme for BPNSs is summarized according to existing methods. Based on the experience of nanomaterial treatment, this paper proposes a research focus for the end treatment of BPNSs in the future, providing a reference scheme for the end treatment of other nanomaterials. Finally, we summarize the full text and propose recommended methods and improvement plans.

Pressure response of carbapenems Klebsiella pneumoniae under antibiotic stress.

To analyze the drug-resistant phenotype and genetic characteristics of Carbapenem resistant Klebsiella pneumoniae (CRKP) in this region, and to study its different expression profiles in RNA level under the pressure of low levels of antibiotics. Trace dilution method and PCR method were used to detect the antibiotic resistance phenotype and antibiotic resistance gene carrying of CRKP strain, simulate the antibiotic stress process, and RNAseq was used to analyze the transcriptomic changes of CRKP strain. 37 CRKP strains, 27 Carbapenem sensitive Klebsiella pneumoniae (CSKP) CSKP strains and 42 sensitive strains were detected. The antibiotic resistance rate of CRKP strain was significantly higher than that of other drug-resistant strains, and there were many kinds of antibiotic resistance genes. Transcriptomic analysis showed that CRKP strain showed compensatory rise under meropenem stress at low concentration, and the expression of genes related to biofilm formation, pressure induction, pressure tolerance and transcriptional regulation was significantly changed. It was speculated that mrkAB, fimDH, phoHP and pspABCD clusters significantly altered their expression under the antibiotics stress response in CRKP strain. The detection rate of CRKP strain is high in this area. Under low levels of antibiotic stress, CRKP strain can not only survive by synthesizing antibiotic modified enzyme, but also respond by transcriptional regulation and biofilm changes, resulting in stress compensation. The discovery of this phenomenon explains the failure of treatment due to improper use of higher-order antibiotics from the perspective of genetic interaction.

Analysis of serum and drug resistance levels between food source and human salmonella / 公共卫生与预防医学

Objective To analyze serotype distribution, drug resistance, quinolone resistance gene carrying status and genetic relationship of foodborne Salmonella and human Salmonella isolates in Changzhou from 2012 to 2018, to provide scientific basis for the prevention and control of Salmonella. Methods The serum type was identified by serum agglutination and liquid chip. The antibiotic sensitivity was determined by micro broth dilution method. The quinolone antibiotic resistance gene was determined by gene sequencing method. The multilocus sequence typing ( MLST ) typing was performed on quinolone-resistant Salmonella, and the genetic relationship was analyzed by BioNumerics 8.0. Results A total of 10 and 36 serotypes were detected in 46 foodborne Salmonella strains and 152 human Salmonella strains, respectively. The dominant serotypes were Indiana Salmonella and Salmonella typhimurium. Erythromycin resistance rate was the highest in both Salmonella strains, and the proportion of multidrug-resistant bacteria was 93.47 % ( 43 / 46 ) and 80.92 % ( 123 / 152 ), respectively. 38 strains of quinolone-resistant foodborne Salmonella GyrA subunit mainly occurred double mutations Asp87Asn, Ser83Phe, ParC subunit mainly occurred single mutation Ser80Arg, 119 strains of quinolone-resistant human Salmonella qnrS gene detection rate was higher, reached 68.1 % ( 81 / 119 ) ; The dominant ST types of quinolone-resistant Salmonella from two sources were ST17 and ST19, respectively. Conclusions The antibiotic sensitivity of the two Salmonella resistant strains from Changzhou was the same ; Synergistic drug resistance, but both quinolone resistance genemutations and carry inconsistent ; The ST type distribution of quinolone resistant strains isalso inconsistent, and the genetic relationship is far. It is suggested that the probability of Salmonella resistant bacteria infection caused by food transmission in our region is small, and the treatment of the two should be differentiated.