Description: The electronic spectra of complex acceptors in compensated CdTe:Cl, CdTe:Ag,Cl, and CdTe:Bi,Cl single crystals are studied using low-temperature photoluminescence (PL) measurements under both nonresonant and resonant excitation of distant donor–acceptor pairs (DAP). The wavelength modulation of the excitation source combined with the analysis of the differential PL signal is used to enhance narrow spectral features obscured because of inhomogeneous line broadening and/or excitation transfer for selectively excited DAPs. For the well-known tetrahedral (T D ) Ag Cd acceptor, the energies of four excited states are measured, and the values obtained are shown to be in perfect agreement with the previous data. Moreover, splitting between the 2P 3/2 (Г 8 ) and 2S 3/2 (Г 8 ) states is clearly observed for Ag Cd centers located at a short distance (5–7 nm) from a hydrogen-like donor (Cl Te ). This splitting results from the reduction of the T D symmetry taking place when the acceptor is a member of a donor–acceptor pair. For the Cl-related complex acceptor with an activation energy of ∼121 meV (A-center), the energies of eight excited states are measured. It is shown that this defect produces low-symmetry central-cell correction responsible for the strong splitting of S-like T D shells. The energy spectrum of the Bi-related shallow acceptor with an activation energy of ∼36 meV is measured as well. The spectrum obtained differs drastically from the hydrogen-like set of levels, which indicates the existence of repulsive low-symmetry perturbation of the hydrogen-like Coulomb potential. It is also shown that the spectra of selectively excited PL recorded for a macroscopic ensemble of distant donor–acceptor pairs allow one to detect the low symmetry of acceptors of a given type caused by their complex nature or by the Jahn–Teller distortion. This method does not require any additional (external) field and is applicable to acceptors in diverse zinc-blende compound semiconductors.

Description: Dendritic cells (DCs) are well-known for their functions in orchestrating the innate and adaptive arms of immune defense. However, under certain conditions, DCs can exert tumoricidal activity. We have elucidated the mechanism of tumor suppression by TLR4-activated bone marrow–derived DCs (BMDCs) isolated from BALB/c mice. We identified that two distinct subsets of BMDCs (CD11b + CD11c + I-A/E int and CD11b + CD11c + I-A/E high ) have different cytotoxic mechanisms of action. The cytotoxicity of the former subset is mediated through NO and reactive oxygen species and type I IFN (IFN-β), whereas the latter subset acts only through IFN-β. TLR4 agonists, LPS or pharmaceutical-grade ImmunoMax, activate CD11c + BMDCs, which, in turn, directly kill 4T1 mouse breast cancer cells or inhibit their proliferation in an MHC-independent manner. These data define two populations of BMDCs with different mechanisms of direct cytotoxicity, as well as suggest that the I-A/E int subset could be less susceptible to counteracting mechanisms in the tumor microenvironment and support investigation of similar subsets in human DCs.

Description: Marine plastic debris floating on the ocean surface is a major environmental problem. However, its distribution in the ocean is poorly mapped, and most of the plastic waste estimated to have entered the ocean from land is unaccounted for. Better understanding of how plastic debris is transported from coastal and marine sources is crucial to quantify and close the global inventory of marine plastics, which in turn represents critical information for mitigation or policy strategies. At the same time, plastic is a unique tracer that provides an opportunity to learn more about the physics and dynamics of our ocean across multiple scales, from the Ekman convergence in basin-scale gyres to individual waves in the surfzone. In this review, we comprehensively discuss what is known about the different processes that govern the transport of floating marine plastic debris in both the open ocean and the coastal zones, based on the published literature and referring to insights from neighbouring fields such as oil spill dispersion, marine safety recovery, plankton connectivity, and others. We discuss how measurements of marine plastics (both in situ and in the laboratory), remote sensing, and numerical simulations can elucidate these processes and their interactions across spatio-temporal scales.