Self-assembly of semiconductor nanoparticles toward emergent behaviors on fluorescence

Due to the unique fluorescence characteristics,superstructures from self-assembly of semiconductor nanoparticles have become essential components of material and chemical science,and thus it has broad application potential in displays,single-photon source,sensing,biological tagging and emerging quantum technologies.Superstructure refers to an artificial functional architecture whose length scale is between the quantum scale and the macroscale.When solely treating this complicated stage fitted from less complicated pieces together(basic nanoparticles)and pile speculation on speculation,we must understand the fundamental questions,that is,what the hierarchy or specialization of function is at the stage.The uniqueness of this stage is not the collection of basic nanoparticles,but the behavior that emerges on fluorescence-basically a new type of behavior.Under the angle of view,this study reviews the advances in the fluorescence of individual semiconductor nanoparticles,inter-nanoparticles coupling and thus emergent fluorescence behaviors of assemblies.We also try to present the methodology for seeking emergent behaviors on fluorescence.

Mixed 2D-Dion–Jacobson/3D Sn-Pb alloyed perovskites for efficient photovoltaic solar devices

Tin-lead(Sn-Pb)alloyed perovskites with tunable bandgaps hold great potential for constructing highly efficient single-junction and tandem photovoltaic devices.However,the efficiency and stability of Sn-Pb perovskite solar cells(PSCs)are greatly hampered by severe nonradiative recombination due to the easy oxidation of Sn(II).In this work,we report the construction of mixed dimensional two-dimensional(2D)Dion–Jacobson(DJ)and three-dimensional(3D)perovskites to improve the efficiency and stability of Sn-Pb alloyed PSCs.Introducing a small amount of 1,4-butanediammonium diiodide as spacer cations of DJ perovskites into precursor,the prepared mixed dimensional Sn-Pb alloyed perovskites exhibit reduced trap-state density due to the passivation of 2D DJ perovskites.As a result,nonradiative charge recombination is greatly suppressed.The prepared Sn-Pb alloyed PSCs based on 2D-DJ/3D heterojunction deliver a power conversion efficiency of 19.02%with an impressive fill factor of 80%.As well,improved device stability is realized due to the presence of DJ perovskites which serves as a protection barrier against oxidation and water invasion.

Advances in the development of molecular genetic tools for Mycobacterium tuberculosis

Mycobacterium tuberculosis, a Gram-positive bacterium of great clinical relevance, is a lethal pathogen owing to its complex physiological characteristics and development of drug resistance. Several molecular genetic tools have been developed in the past few decades to study this microorganism. These tools have been instrumental in understanding how M. tuberculosis became a successful pathogen. Advanced molecular genetic tools have played a significant role in exploring the complex pathways involved in M. tuberculosis pathogenesis. Here, we review various molecular genetic tools used in the study of M. tuberculosis. Further, we discuss the applications of clustered regularly interspaced short palindromic repeat interference（CRISPRi）, a novel technology recently applied in M. tuberculosis research to study target gene functions. Finally, prospective outcomes of the applications of molecular techniques in the field of M. tuberculosis genetic research are also discussed.

Ultra-short-course and intermittent TB47-containing oral regimens produce stable cure against Buruli ulcer in a murine model and prevent the emergence of resistance for Mycobacterium ulcerans

Buruli ulcer(BU),caused by Mycobacterium ulcerans,is currently treated with rifampin estreptomycin or rifampineclarithromycin daily for 8 weeks recommended by World Health Organization(WHO).These options are lengthy with severe side effects.A new anti-tuberculosis drug,TB47,targeting QcrB in cytochrome bc1:aa3 complex is being developed in China.TB47-containing regimens were evaluated in a well-established murine model using an autoluminescent M.ulcerans strain.Highlevel TB47-resistant spontaneous M.ulcerans mutants were selected and their qcrB genes were sequenced.The in vivo activities of TB47 against both low-level and high-level TB47-resistant mutants were tested in BU murine model.Here,we show that TB47-containing oral 3-drug regimens can completely cure BU in 2 weeks for daily use or in 3 weeks given twice per week(6 doses in total).All high-level TB47-resistant mutants could only be selected using the low-level mutants which were still sensitive to TB47 in mice.This is the first report of double mutations in QcrB in mycobacteria.In summary,TB47-containing regimens have promise to cure BU highly effectively and prevent the emergence of drug resistance.Novel QcrB mutations found here may guide the potential clinical molecular diagnosis of resistance and the discovery of new drugs against the high-level resistant mutants.

Optimal Design of 850nm 2 × 2 Multimode Interference Polymer Waveguide Coupler by Imprint Technique

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