Prevailing Intermolecular Bonding for Dinitrotoluene Self-Assembled Monolayers on Au(111)

The self-assembly of 2,4- and 2,6-dinitrotoluene was investigated on Au(111) surfaces using a combined experimental and density functional theory approach. Well-ordered monolayers were observed with rectangular unit cells commensurate with the Au substrate along the next-nearest-neighbor direction. The unit cell is made of two molecules per cell in an unusual vertical configuration, driven by a strong dipole–dipole interaction between molecules and with lesser interaction with the substrate. van der Waals density functional theory models of bonding in the molecular layer show strong intermolecular interactions that dominate over substrate interactions with cohesive energies near 24 kcal/mol. The calculations are corroborated by temperature-programmed desorption experiments and demonstrate that intermolecular interactions dominate the self-assembly of this molecular adsorption system. Both dipole–dipole and van der Waals interactions are significant contributors to the bonding, and the importance of van der Waals corrected density functional theory is shown. We argue that the molecule–molecule vs molecule–substrate interactions are controlled by the optimization of energy per unit surface area

Influence of light intensity on chloroplast development and pigment accumulation in the wild-type and etiolated mutant plants of <i>Anthurium andraeanum</i> ‘Sonate’

<p>Seedlings of wild-type and etiolate mutant plants of <i>Anthurium andraeanum</i> cultivar ‘Sonate’ were treated for 15 d with different light intensities (20, 100, and 400 µmol·m⁻²·s⁻¹) to analyze leaf plastid development and pigment content. Significant changes appeared in treated seedlings, including in leaf color, plastid ultrastructure, chloroplast development gene <i>AaGLK</i> expression, chlorophyll and anthocyanin contents, and protoplast shape. Wild-type and etiolated plants exhibited different plastid structures under the same light condition. The results suggest that light intensity is a crucial environmental factor influencing plastid development and leaf color formation in the <i>A. andraeanum</i> cultivar ‘Sonate’.</p

Transient Sub-bandgap States in Halide Perovskite Thin Films

Metal halide perovskites are promising solar energy materials, but their mechanism of action remains poorly understood. It has been conjectured that energetically stabilized states such as those corresponding to polarons, quasiparticles in which the carriers are dressed with phonons, are responsible for their remarkable photophysical properties. Yet, no direct evidence of polarons or other low-energy states have been reported despite extensive efforts. Such states should manifest as below bandgap features in transient absorption and photoluminescence measurements. Here, we use single-particle transient absorption microscopy on MAPbI₃ (MA = methylammonium) to unambiguously identify spectrally narrow sub-bandgap states directly; we demonstrate that such signals are completely averaged away in ensemble measurements. Carrier temperature-dependent studies suggest that hot carriers are directed toward transient low-energy states which are immune from permanent defects and traps, thereby giving rise to low carrier recombination rates and ultimately high power conversion efficiency in devices. The utilization of short-lived sub-bandgap states may be a key design principle that propels widespread use of highly heterogeneous materials in optoelectronic applications

Supplement 1: Orbital-angular-momentum-preserving helical Bloch modes in twisted photonic crystal fiber

Originally published in Optica on 20 September 2014 (optica-1-3-165

A Site-Specific Integrative Plasmid Found in Pseudomonas aeruginosa Clinical Isolate HS87 along with A Plasmid Carrying an Aminoglycoside-Resistant Gene

Plasmids play critical roles in bacterial fitness and evolution of Pseudomonas aeruginosa. Here two plasmids found in a drug-resistant P. aeruginosa clinical isolate HS87 were completely sequenced. The pHS87b plasmid (11.2 kb) carries phage-related genes and function-unknown genes. Notably, pHS87b encodes an integrase and has an adjacent tRNAThr-associated attachment site. A corresponding integrated form of pHS87b at the tRNAThr locus was identified on the chromosome of P. aeruginosa, showing that pHS87b is able to site-specifically integrate into the 3'-end of the tRNAThr gene. The pHS87a plasmid (26.8 kb) displays a plastic structure containing a putative replication module, stability factors and a variable region. The RepA of pHS87a shows significant similarity to the replication proteins of pPT23A-family plasmids. pHS87a carries a transposon Tn6049, a truncated insertion sequence ΔIS1071 and a Tn402-like class 1 integron which contains an aacA4 cassette that may confer aminoglycoside resistance. Thus, pHS87b is a site-specific integrative plasmid whereas pHS87a is a plastic antibiotic resistance plasmid. The two native plasmids may promote the fitness and evolution of P. aeruginosa

Supplement 1: Stable subpicosecond soliton fiber laser passively mode-locked by gigahertz acoustic resonance in photonic crystal fiber core

Originally published in Optica on 20 April 2015 (optica-2-4-339

Characterization of influenza A virus specific M2e-PP entrapped PLGA-NP.

<p>(A) The surface morphology of M2e-PP entrapped PLGA-NP (x7K) showing spherical and uniform sized particles; (B) Size distribution of M2e-PP entrapped PLGA-NP; (C) <i>In vitro</i> protein release profile of M2e-PP entrapped PLGA-NP.</p

Immunophenotyping of activated lymphocyte subsets in LMNCs of vaccinated and SwIV challenged pigs.

<p>(A) A representative flow cytometry plots depicting porcine IFNγ positive T lymphocytes subpopulations. Gating pattern of lymphocytes of a pig infected with SwIV H1N1 and restimulated <i>ex vivo</i> with the virus for 3 days and immunostained using fluorochrome conjugated pig specific CD3έ, CD4α and CD8α markers and intracellular IFNγ to identify the frequency of CD3⁺CD4⁺CD8α⁺IFNγ⁺, CD3⁺CD4^-CD8α⁺IFNγ⁺ and CD3⁺CD4⁺CD8α^-IFNγ⁺ cells is shown. Lung MNCs <b>(</b>LMNCs) isolated on the day of necropsy from all the experimental pigs were either unstimulated (Control, C) or stimulated with the SwIV (V), conserved peptides (A1, A2, A7 and A8 peptides) or M2e (M) for 3 days and immunostained cells were gated for T cell subsets as described above for: (B) CD3⁺CD4⁺CD8α⁺IFNγ⁺; (C) CD3⁺CD4^-CD8α⁺IFNγ⁺; and (D) CD3⁺CD4⁺CD8α^-IFNγ⁺ cells. (E) Delineating the SwIV specific T cell response in NPP vaccinated pigs. Three activated (IFNγ⁺) T lymphocyte subsets in the LMNCs of only NPP vaccinated pigs either unstimulated (Control, C) or stimulated with the SwIV or indicated peptides are shown. A white dotted line drawn across each T cell subset separates the Ags specific recalled T cell response over the control unstimulated cells of NPP vaccinated pigs. (F) Secreted IFNγ in the culture supernatant of virus restimulated LMNCs of vaccinated and SwIV challenged pigs was analyzed by ELISA. Background cytokine levels from each pig groups were subtracted from the specific stimulation. Each bar indicates the average frequency of indicated T cell subset or cytokine from 6 or 7 pigs ± SEM. Asterisk denotes statistically significant difference at P<0.05 (*), P<0.01 (**) and P<0.001 (***) between the indicated two pig groups determined by One way ANOVA followed by Tukey Post-hoc test for the significance between the indicated pig groups.</p

Humoral immune response in vaccinated and SwIV challenged pigs.

<p>In pre-challenge pigs, the levels of specific IgG in plasma against (A) H1N1 SwIV and (B) SwIV M2e protein at DPC 0. In post-challenge pigs at DPC 7, the levels of SwIV specific IgA and IgG antibody titers (C and D); hemagglutination inhibition (HI) titers (E and F); and virus neutralization (VN) titers (G and H) in the BAL fluid and plasma samples, respectively, are shown. Each bar represents the average titer of 6 or 7 pigs ± SEM. The data of antibody titers shown in the graph are corrected values after subtracting from the background OD values.</p

Clinical outcome and virus load in the lungs of vaccinated and SwIV challenged pigs.

<p>(A) Rectal temperature was recorded everyday post-challenge (day -1 to 7). SwIV titer in BAL fluid at DPC 7 was detected by (B) viral RNA load by qRT-PCR, and (C) replicating infectious virus load using MDCK cells by immunofluorescence assay. The ratio indicated above each bar represents the number of pigs positive for virus and contributed to the data out of 6 or 7 animals. The viral titer is expressed in tissue culture infective dose 50 (TCID₅₀) in each ml of the BAL fluid. Each data point or bar represents the average value of 6 to 7 pigs ± SEM. Asterisk denotes statistically significant difference at P<0.05 (*) between MKC and NPP or NPA pig groups determined by One way ANOVA followed by Tukey Post-hoc test.</p