Human subjects were experimentally infected with Haemophilus ducreyi for up to 2 weeks. Bacterial suspensions were delivered into the epidermis and dermis through puncture wounds made by an allergy-testing device. Subjects developed papular lesions that evolved into pustules resembling natural disease. Some papular lesions resolved spontaneously, indicating that host responses may clear infection. Bacteria were shed intermittently from lesions, suggesting that H. ducreyi may be transmissible before ulceration. Host responses to infection consisted primarily of cutaneous infiltrate of polymorphonuclear leukocytes, Langerhans cells, macrophages, and CD4 T cells of alpha beta lineage. Expression of HLA-DR by keratinocytes was associated with the presence of interferon-gamma mRNA in the skin. There was little evidence for humoral or peripheral blood mononuclear cell responses to bacterial antigens. The cutaneous infiltrate of CD4 cells and macrophages provides a mechanism that facilitates transmission of human immunodeficiency virus by H. ducreyi.

The output enhancement of a green InGaN/GaN quantum-well (QW) light-emitting diode (LED) through the coupling of a QW with localized surface plasmons (LSPs), which are generated on Ag nanostructures on the top of the device, is demonstrated. The suitable Ag nanostructures for generating LSPs of resonance energies around the LED wavelength are formed by controlling the Ag deposition thickness and the post-thermal-annealing condition. With a 20 mA current injected onto the LED, enhancements of up to 150% in electroluminescence peak intensity and of 120% in integrated intensity are observed. By comparing this with a similar result for a blue LED previously published, it is confirmed that surface plasmon coupling for emission enhancement can be more effective for an InGaN/GaN QW of lower crystal quality, which normally corresponds to the emission of a longer wavelength.

The ferric iron-binding protein (Fbp) expressed by pathogenic Neisseria spp. has been proposed to play a central role in the high-affinity acquisition of iron from human transferrin. The results of this investigation provide evidence that Fbp participates in this process as a functional analogue of a Gram-negative periplasmic-binding protein component, which operates as a part of a general active transport process for the receptor-mediated, high-affinity transport of iron from human transferrin. Known properties of Fbp are correlated with those of other well-characterized periplasmic-binding proteins, including structural features and the reversible binding of ligand. Predictive of a periplasmic-binding protein, which functions in the high-affinity acquisition of iron, is that Fbp is a transient participant in the process of iron acquisition from human transferrin. Evidence for this is demonstrated by results of pulse-chase experiments. Taken together, the data described here and elsewhere suggest that pathogenic Neisseria spp. use a periplasmic-binding protein-mediated active transport mechanism for the acquisition of iron from human transferrin.

The authors demonstrate the coupling effects between the quantum well ͑QW͒ and surface plasmon ͑SP͒ generated nearby on the p-type side in an InGaN / GaN single-QW light-emitting diode ͑LED͒. The QW-SP coupling leads to the enhancement of the electroluminescence ͑EL͒ intensity in the LED sample designed for QW-SP coupling and reduced SP energy leakage, when compared to a LED sample of weak QW-SP coupling or significant SP energy loss. In the LED samples of significant QW-SP coupling, the blueshifts of the photoluminescence and EL emission spectra are observed, indicating one of the important features of such a coupling process. The device performance can be improved by using the n-type side for SP generation such that the device resistance can be reduced and the QW-SP coupling effect can be enhanced ͑by further decreasing the distance between the QW and metal͒ because of the higher carrier concentration in the n-type layer.

Abstract. We developed a TaqMan-based real-time quadriplex polymerase chain reaction (PCR) to simultaneously detect Treponema pallidum subspecies pallidum, T. pallidum subsp. pertenue, and T. pallidum subsp. endemicum, the causative agents of venereal syphilis, yaws, and bejel, respectively. The PCR assay was applied to samples from skin ulcerations of clinically presumptive yaws cases among children on Tanna Island, Vanuatu. Another real-time triplex PCR was used to screen for the point mutations in the 23S rRNA genes that have previously been associated with azithromycin resistance in T. pallidum subsp. pallidum strains. Seropositivity by the classical syphilis serological tests was 35.5% among children with skin ulcerations clinically suspected with yaws, whereas the presence of T. pallidum subsp. pertenue DNA was only found in lesions from 15.5% of children. No evidence of T. pallidum subsp. pertenue infection, by either PCR or serology was found in~59% of cases indicating alternative causes of yaws-like lesions in this endemic area.