Polarization control of metal-enhanced fluorescence in hybrid assemblies of photosynthetic complexes and gold nanorods

Fluorescence imaging of hybrid nanostructures composed of a bacterial light-harvesting complex LH2 and Au nanorods with controlled coupling strength is employed to study the spectral dependence of the plasmon-induced fluorescence enhancement. Perfect matching of the plasmon resonances in the nanorods with the absorption bands of the LH2 complexes facilitates a direct comparison of the enhancement factors for longitudinal and transverse plasmon frequencies of the nanorods. We find that the fluorescence enhancement due to excitation of longitudinal resonance can be up to five-fold stronger than for the transverse one. We attribute this result, which is important for designing plasmonic functional systems, to a very different distribution of the enhancement of the electric field due to the excitation of the two characteristic plasmon modes in nanorods

GTP cyclohydrolase I gene polymorphisms are associated with endothelial dysfunction and oxidative stress in patients with type 2 diabetes mellitus

Background: The genetic background of atherosclerosis in type 2 diabetes mellitus (T2DM) is complex and poorly understood. Studying genetic components of intermediate phenotypes, such as endothelial dysfunction and oxidative stress, may aid in identifying novel genetic components for atherosclerosis in diabetic patients.<p></p> Methods: Five polymorphisms forming two haplotype blocks within the GTP cyclohydrolase 1 gene, encoding a rate limiting enzyme in tetrahydrobiopterin synthesis, were studied in the context of flow and nitroglycerin mediated dilation (FMD and NMD), intima-media thickness (IMT), and plasma concentrations of von Willebrand factor (vWF) and malondialdehyde (MDA).<p></p> Results: Rs841 was associated with FMD (p = 0.01), while polymorphisms Rs10483639, Rs841, Rs3783641 (which form a single haplotype) were associated with both MDA (p = 0.012, p = 0.0015 and p = 0.003, respectively) and vWF concentrations (p = 0.016, p = 0.03 and p = 0.045, respectively). In addition, polymorphism Rs8007267 was also associated with MDA (p = 0.006). Haplotype analysis confirmed the association of both haplotypes with studied variables.<p></p> Conclusions: Genetic variation of the GCH1 gene is associated with endothelial dysfunction and oxidative stress in T2DM patients

Comparing large lecture mechanics curricula using the Force Concept Inventory: A five thousand student study

The performance of over 5000 students in introductory calculus-based mechanics courses at the Georgia Institute of Technology was assessed using the Force Concept Inventory (FCI). Results from two different curricula were compared: a traditional mechanics curriculum and the Matter & Interactions (M&I) curriculum. Post-instruction FCI averages were significantly higher for the traditional curriculum than for the M&I curriculum; the differences between curricula persist after accounting for factors such as pre-instruction FCI scores, grade point averages, and SAT scores. FCI performance on categories of items organized by concepts was also compared; traditional averages were significantly higher in each concept. We examined differences in student preparation between the curricula and found that the relative fraction of homework and lecture topics devoted to FCI force and motion concepts correlated with the observed performance differences. Limitations of concept inventories as instruments for evaluating curricular reforms are discussed.Comment: 21 pages, 4 figures, submitted to Am. J. Phys. arXiv admin note: substantial text overlap with arXiv:1112.559

Forward Neutron Production at the Fermilab Main Injector

We have measured cross sections for forward neutron production from a variety of targets using proton beams from the Fermilab Main Injector. Measurements were performed for proton beam momenta of 58 GeV/c, 84 GeV/c, and 120 GeV/c. The cross section dependence on the atomic weight (A) of the targets was found to vary as $A^(alpha)$ where $\alpha$ is $0.46\pm0.06$ for a beam momentum of 58 GeV/c and 0.54$\pm$0.05 for 120 GeV/c. The cross sections show reasonable agreement with FLUKA and DPMJET Monte Carlos. Comparisons have also been made with the LAQGSM Monte Carlo.Comment: Accepted for publication in Physical Review D. This version incorporates small changes suggested by referee and small corrections in the neutron production cross sections predicted by FLUK

Structural chemistry of metal coordination complexes at high pressure

The application of pressures of up to about 10 GPa may induce significant geometric, configurational, conformational and packing changes in molecular solids. This review highlights and describes recent advances in high pressure studies of coordination complexes, many of which have been conducted at synchrotrons or other central facilities. The main focus is on the wide range of geometric changes which occur with pressure. In some cases these changes have associated physical effects, and the review describes materials exhibiting negative linear compressibility, spin cross-over phenomena, magnetism and molecular conduction, as well as detailing the exciting possibilities for future developments in this area of research

A synthetic biological quantum optical system

In strong plasmon–exciton coupling, a surface plasmon mode is coupled to an array of localized emitters to yield new hybrid light–matter states (plexcitons), whose properties may in principle be controlled via modification of the arrangement of emitters. We show that plasmon modes are strongly coupled to synthetic light-harvesting maquette proteins, and that the coupling can be controlled via alteration of the protein structure. For maquettes with a single chlorin binding site, the exciton energy (2.06 ± 0.07 eV) is close to the expected energy of the Qy transition. However, for maquettes containing two chlorin binding sites that are collinear in the field direction, an exciton energy of 2.20 ± 0.01 eV is obtained, intermediate between the energies of the Qx and Qy transitions of the chlorin. This observation is attributed to strong coupling of the LSPR to an H-dimer state not observed under weak coupling

Plasma Levels of Transforming Growth Factor-β1 Reflect Left Ventricular Remodeling in Aortic Stenosis

Background: TGF-b1 is involved in cardiac remodeling through an auto/paracrine mechanism. The contribution of TGF-b1 from plasmatic source to pressure overload myocardial remodeling has not been analyzed. We investigated, in patients with valvular aortic stenosis (AS), and in mice subjected to transverse aortic arch constriction (TAC), whether plasma TGF-b1 relates with myocardial remodeling, reflected by LV transcriptional adaptations of genes linked to myocardial hypertrophy and fibrosis, and by heart morphology and function. Methodology/Principal Findings: The subjects of the study were: 39 patients operated of AS; 27 healthy volunteers; 12 mice subjected to TAC; and 6 mice sham-operated. Myocardial samples were subjected to quantitative PCR. Plasma TGF-b1 was determined by ELISA. Under pressure overload, TGF-b1 plasma levels were significantly increased both in AS patients and TAC mice. In AS patients, plasma TGF-b1 correlated directly with aortic transvalvular gradients and LV mass surrogate variables, both preoperatively and 1 year after surgery. Plasma TGF-b1 correlated positively with the myocardial expression of genes encoding extracellular matrix (collagens I and III, fibronectin) and sarcomeric (myosin light chain-2, b-myosin heavy chain) remodelling targets of TGF-b1, in TAC mice and in AS patients. Conclusions/Significance: A circulating TGF-b1-mediated mechanism is involved, in both mice and humans, in the excessive deposition of ECM elements and hypertrophic growth of cardiomyocytes under pressure overload. The possible value of plasma TGF-b1 as a marker reflecting preoperative myocardial remodeling status in AS patients deserves further analysis in larger patient cohorts

Direct Gene Transfer with IP-10 Mutant Ameliorates Mouse CVB3-Induced Myocarditis by Blunting Th1 Immune Responses

Background: Myocarditis is an inflammation of the myocardium that often follows the enterovirus infections, with coxsackievirus B3 (CVB3) being the most dominant etiologic agent. We and other groups previously reported that chemokine IP-10 was significantly induced in the heart tissue of CVB3-infected mice and contributed to the migration of massive inflammatory cells into the myocardium, which represents one of the most important mechanisms of viral myocarditis. To evaluate the direct effect of IP-10 on the inflammatory responses in CVB3 myocarditis, herein an IP-10 mutant deprived of chemo-attractant function was introduced into mice to antagonize the endogenous IP-10 activity, and its therapeutic effect on CVB3-induced myocarditis was evaluated. Methodology/Principal Findings: The depletion mutant pIP-10-AT, with an additional methionine after removal of the 5 N-terminal amino acids, was genetically constructed and intramuscularly injected into BALB/c mice after CVB3 infection. Compared with vector or no treatment, pIP-10-AT treatment had significantly reduced heart/body weight ratio and serum CK-MB level, increased survival rate and improved heart histopathology, suggesting an ameliorated myocarditis. This therapeutic effect was not attributable to an enhanced viral clearance, but to a blunted Th1 immune response, as evidenced by significantly decreased splenic CD4 + /CD8 + IFN-c + T cell percentages and reduced myocardial Th1 cytokine levels. Conclusion/Significance: Our findings constitute the first preclinical data indicating that interfering in vivo IP-10 activit

The Cyst-Theca Relationship Of The Dinoflagellate Cyst Trinovantedinium Pallidifulvum, With Erection Of Protoperidinium Lousianensis Sp Nov And Their Phylogenetic Position Within The Conica Group

We establish the cyst-theca relationship of the dinoflagellate cyst species Trinovantedinium pallidifulvum Matsuoka 1987 based on germination experiments of specimens isolated from the Gulf of Mexico. We show that the motile stage is a new species, designated as Protoperidinium louisianensis. We also determine its phylogenetic position based on single-cell polymerase chain reaction (PCR) of a single cell germinated from the Gulf of Mexico cysts. To further refine the phylogeny, we determined the large subunit (LSU) sequence through single-cell PCR of the cyst Selenopemphix undulata isolated from Brentwood Bay (Saanich Inlet, BC, Canada). The phylogeny shows that P. louisianensis is closest to P. shanghaiense, the motile stage of T. applanatum, and is consistent with the monophyly of the genus Trinovantedinium. Selenopemphix undulata belongs to a different clade than Selenopemphix quanta (alleged cyst of P. conicum), suggesting that the genus Selenopemphix is polyphyletic. Trinovantedinium pallidifulvum is widely distributed with occurrences in the Gulf of Mexico, the North Atlantic, the northeast Pacific and southeast Asia. In addition, we illustrate the two other extant species, Trinovantedinium applanatum and Trinovantedinium variabile, and two morphotypes of Trinovantedinium. Geochemical analyses of the cyst wall of T. pallidifulvum indicate the presence of amide groups in agreement with other heterotrophic dinoflagellate species, although the cyst wall of T. pallidifulvum also includes some unique features

Catalytic gas-phase glycerol processing over SiO2-, Cu-, Ni-and Fe-supported Au nanoparticles

In this study, we investigated different metal pairings of Au nanoparticles (NPs) as potential catalysts for glycerol dehydration for the first time. All of the systems preferred the formation of hydroxyacetone (HYNE). Although the bimetallics that were tested, i.e., Au NPs supported on Ni, Fe and Cu appeared to be more active than the Au/SiO2 system, only Cu supported Au NPs gave high conversion (ca. 63%) and selectivity (ca. 70%) to HYNE