A ligand-assisted matrix to regulate surface and packing states of perovskite quantum dots (QDs) is demonstrated, which involves a ligand exchange and a mild thermal annealing process that are triggered by guanidinium thiocyanate. Consequently, the CsPbI 3 QD solar cells (QDSCs) deliver a champion power conversion efficiency of 15.21%, which is the highest report among all CsPbI 3 QDSCs.

Two-component signal transduction systems play an important role in the ability of bacteria to adapt to various environments by sensing changes in their habitat and by altering gene expression. In this study, we report a novel two-component system, YhcSR, in Staphylococcus aureus which is required for bacterial growth in vitro. We found that the down-regulation of yhcSR expression by induced yhcS antisense RNA can inhibit and terminate bacterial growth. Moreover, without complementary yhcS or yhcR, no viable yhcS or yhcR gene replacement mutant was recoverable. Collectively, these results demonstrated that the YhcSR regulatory system is indispensable for S. aureus growth in culture. Moreover, induced yhcS antisense RNA selectively increased bacterial susceptibility to phosphomycin. These data suggest that YhcSR probably modulates the expression of genes critical for bacterial survival and may be a potential target for the development of novel antibacterial agents.Staphylococcus aureus is an important community-and hospital-acquired pathogen that causes superficial skin and lifethreatening infections worldwide (25,33). The pathogenesis of S. aureus is partially due to the coordinated regulation of virulence factors allowing the bacterium to evade the host immune system and/or to promote survival during infection. This organism has developed a series of two-component signal transduction systems (TCSs) in order to sense its immediate surroundings and to modulate specific cellular responses and the expression of virulence genes (14, 32). Therefore, TCSs are being explored as potential targets for new antimicrobials (2,17,28).A typical TCS is composed of a membrane-associated histidine kinase, which acts as a sensor protein extending through the cytoplasmic membrane to monitor environmental changes and to activate a response regulator existing in the cytoplasm modulating gene expression (15,34). The well-studied TCS Agr is a positive regulator of exoproteins, including proteases, hemolysins, and toxins (32). Additionally, the TCS Agr is a repressor of the transcription of protein A, coagulase, and some adhesins in late-exponential-phase growth in vitro (32). Other two-component systems, such as saeRS, arlRS, and srrAB, also influence the expression of some virulence factors (1,13,11,35,39). Another system, LytSR, controls bacterial autolysis by positively regulating the transcription of genes responsible for the synthesis and transport of cell wall murein hydrolase (4). The vraSR loci are homologous to the yvqEC loci of B. subtilis and positively modulate cell wall biosynthesis in S. aureus (23).The yycFG system, which has orthologs in Bacillus subtilis (7,8) and Streptococcus pneumoniae (36), is the only known regulatory system essential for cell viability in S. aureus (26). It was reported that in B. subtilis the YycFG system controls the ftsAZ operon, which is involved in the process of cell wall division (12). However, there is no such evidence in S. aureus and S. pneumoniae, while it has been reported that YycF ...

We assessed the gaseous, particulate, and genotoxic pollutants from two current technology gasoline direct injection vehicles when tested in their original configuration and with a catalyzed gasoline particulate filter (GPF). Testing was conducted over the LA92 and US06 Supplemental Federal Test Procedure (US06) driving cycles on typical California E10 fuel. The use of a GPF did not show any fuel economy and carbon dioxide (CO) emission penalties, while the emissions of total hydrocarbons (THC), carbon monoxide (CO), and nitrogen oxides (NOx) were generally reduced. Our results showed dramatic reductions in particulate matter (PM) mass, black carbon, and total and solid particle number emissions with the use of GPFs for both vehicles over the LA92 and US06 cycles. Particle size distributions were primarily bimodal in nature, with accumulation mode particles dominating the distribution profile and their concentrations being higher during the cold-start period of the cycle. Polycyclic aromatic hydrocarbons (PAHs) and nitrated PAHs were quantified in both the vapor and particle phases of the PM, with the GPF-equipped vehicles practically eliminating most of these species in the exhaust. For the stock vehicles, 2-3 ring compounds and heavier 5-6 ring compounds were observed in the PM, whereas the vapor phase was dominated mostly by 2-3 ring aromatic compounds.

Staphylococcus aureus is an important opportunistic pathogen and is the etiological agent of many hospital-and community-acquired infections. The golden pigment, staphyloxanthin, of S. aureus colonies distinguishes it from other staphylococci and related Gram-positive cocci. Staphyloxanthin is the product of a series of biosynthetic steps that produce a unique membrane-embedded C 30 golden carotenoid and is an important antioxidant. We observed that a strain with an inducible airR overexpression cassette had noticeably increased staphyloxanthin production compared to the wild-type strain under aerobic culturing conditions. Further analysis revealed that depletion or overproduction of the AirR response regulator resulted in a corresponding decrease or increase in staphyloxanthin production and susceptibility to killing by hydrogen peroxide, respectively. Furthermore, the genetic elimination of staphyloxanthin during AirR overproduction abolished the protective phenotype of increased staphyloxanthin production in a whole-blood survival assay. Promoter reporter and gel shift assays determined that the AirR response regulator is a direct positive regulator of the staphyloxanthin-biosynthetic operon, crtOPQMN, but is epistatic to alternative sigma factor B. Taken together, these data indicate that AirSR positively regulates the staphyloxanthin-biosynthetic operon crtOPQMN, promoting survival of S. aureus in the presence of oxidants.KEYWORDS: S. aureus, staphyloxanthin, transcriptional regulation, AirSR, twocomponent regulatory systems S taphylococcus aureus is a leading bacterial agent of hospital-and communityacquired infections ranging from infective endocarditis and osteomyelitis to soft tissue infection (1). S. aureus possesses a vast array of adhesion and virulence factors that allow the organism to infect any part of the body and efficiently evade the immune system. S. aureus colonies are orange to golden (hence the species name, aureus), which was previously used as a distinguishing characteristic and is now recognized as the product of an important virulence factor (2).The distinctive golden pigment of S. aureus is the biosynthetic product of crtOPQMN and aldH (3, 4). The final product of this six-enzyme-biosynthetic pathway is a membrane-embedded golden C 30 triterpenoid carotenoid, ␣-D-glucopyranosyl-1-O-(4,4=-diaponeurosporen-4-oate)-6-O-(12-methyltetradecanoate), termed staphyloxanthin (STX) (5). STX is an antioxidant (6) and an important virulence factor of S. aureus, promoting intracellular phagocyte survival, and is linked to resistance to reactive oxygen species (ROS) produced by the NADPH oxidase system within the phagocyte phagosome (2).

Heterojunctions formed by ultrathin conductive polymer [poly(3,4‐ethylenedioxythiophene): poly(styrenesulfonate)—PEDOT:PSS] films and n‐type crystalline silicon are investigated by photoelectron spectroscopy. Large shifts of Si 2p core levels upon PEDOT:PSS deposition provide evidence that a dopant‐free p–n junction, i.e., an inversion layer, is formed within Si. Among the investigated PEDOT:PSS formulations, the largest induced band bending within Si (0.71 eV) is found for PH1000 (high PEDOT content) combined with a wetting agent and the solvent additive dimethyl sulfoxide (DMSO). Without DMSO, the induced band bending is reduced, as is also the case with a PEDOT:PSS formulation with higher PSS content. The interfacial energy level alignment correlates well with the characteristics of PEDOT:PSS/n‐Si solar cells, where high polymer conductivity and sufficient Si‐passivation are also required to achieve high power conversion efficiency.