Atomic Layer Deposition of CdS Quantum Dots for Solid‐State Quantum Dot Sensitized Solar Cells

Functioning quantum dot (QD) sensitized solar cells have been fabricated using the vacuum deposition technique atomic layer deposition (ALD). Utilizing the incubation period of CdS growth by ALD on TiO₂, we are able to grow QDs of adjustable size which act as sensitizers for solid‐state QD‐sensitized solar cells (ssQDSSC). The size of QDs, studied with transmission electron microscopy (TEM), varied with the number of ALD cycles from 1‐10 nm. Photovoltaic devices with the QDs were fabricated and characterized using a ssQDSSC device architecture with 2,2',7,7'‐tetrakis‐(N,N‐di‐p methoxyphenylamine) 9,9'‐spirobifluorene (spiro‐OMeTAD) as the solid‐state hole conductor. The ALD approach described here can be applied to fabrication of quantum‐confined structures for a variety of applications, including solar electricity and solar fuels. Because ALD provides the ability to deposit many materials in very high aspect ratio substrates, this work introduces a strategy by which material and optical properties of QD sensitizers may be adjusted not only by the size of the particles but also in the future by the composition.     

Expression of the human atypical kinase ADCK3 rescues coenzyme Q biosynthesis and phosphorylation of Coq polypeptides in yeast coq8 mutants

Coenzyme Q (ubiquinone or Q) is a lipid electron and proton carrier in the electron transport chain. In yeast Saccharomyces cerevisiae eleven genes, designated COQ1 through COQ9, YAH1 and ARH1, have been identified as being required for Q biosynthesis. One of these genes, COQ8 (ABC1), encodes an atypical protein kinase, containing six (I, II, III, VIB, VII, and VIII) of the twelve motifs characteristically present in canonical protein kinases. Here we characterize seven distinct Q-less coq8 yeast mutants and show that unlike the coq8 null mutant, each maintained normal steady-state levels of the Coq8 polypeptide. The phosphorylation states of Coq polypeptides were determined with two-dimensional gel analyses. Coq3p, Coq5p, and Coq7p were phosphorylated in a Coq8p-dependent manner. Expression of a human homolog of Coq8p, ADCK3(CABC1) bearing an amino-terminal yeast mitochondrial leader sequence, rescued growth of yeast coq8 mutants on medium containing a nonfermentable carbon source and partially restored biosynthesis of Q(6). The phosphorylation state of several of the yeast Coq polypeptides was also rescued, indicating a profound conservation of yeast Coq8p and human ADCK3 protein kinase function in Q biosynthesis.     

Oxygen‐Deficient Blue TiO2 for Ultrastable and Fast Lithium Storage

Developing a titanium dioxide (TiO₂)‐based anode with superior high‐rate capability and long‐term cycling stability is important for efficient energy storage. Herein, a simple one‐step approach for fabricating blue TiO₂ nanoparticles with oxygen vacancies is reported. Oxygen vacancies can enlarge lattice spaces, lower charge transfer resistance, and provide more active sites in TiO₂ lattices. As a result, this blue TiO₂ electrode exhibits a highly reversible capacity of 50 mAh g^?1 at 100 C (16 800 mA g^?1) even after 10 000 cycles, which is attributable to the combination of surface capacitive process and remarkable diffusion‐controlled insertion revealed by the kinetic analysis. The strategy of employing oxygen‐deficient nanoparticles may be extended to the design of other robust semiconductor materials as electrodes for energy storage.     

Parasites paralyze cellular host defense system to promote virulence

To promote their survival, intracellular pathogens must confront microbicidal activities induced by interferons. In this issue of Cell Host & Microbe, Fentress et?al. show that Toxoplasma gondii evades intracellular killing by deploying a virulence determinant, ROP18, which acts by directly phosphorylating and disabling an IFN-γ-inducible immunity-related GTPase involved in pathogen clearance.     

Characterization of phytoplankton assemblages in a tropical coastal environment using Kohonen self‐organizing map

This study was aimed at understanding the main abiotic environmental factors controlling the distribution patterns of abundance and composition of phytoplankton (size less than 10 μm) assemblages in the coastal waters of south‐eastern Côte d'Ivoire. Data were collected during two cruises, in January (low‐water period) and October (high‐water period) of 2014. A total of 67 species were identified and assigned to Bacillariophyceae (49%), Cyanophyceae (21%), Chlorophyceae (13%), Euglenophyceae (10%), Dinophyceae (4%) and Chrysophyceae (3%). Three biotic zones (I, IIA and IIB) were distinguishable on a Kohonen self‐organizing map after an unsupervised learning process. The diatom genera Eunotia sp., Navicula sp. and Actinoptychus senarius are significantly associated with I, IIA and IIB biotic zones, respectively. A clear seasonal cum salinity trend was apparent in phytoplankton distribution patterns. Turbidity and nitrate levels were the main abiotic factors controlling phytoplankton distribution in I, the upland tidal regions of the lagoon. In regions along the lagoon–sea continuum, phosphate and turbidity exert the most control during the low‐water season (IIA), while total dissolved solids control phytoplankton distribution during the high‐water season (IIB). These are climate‐sensitive parameters whose concentrations depend on prevailing hydroclimatic processes. Therefore, seasonality can have important consequences on phytoplankton community and inadvertently the productivity of these systems.