An outbreak of respiratory diphtheria occurred in two health districts in the province of KwaZulu-Natal in South Africa in 2015. A multidisciplinary outbreak response team was involved in the investigation and management of the outbreak. Fifteen cases of diphtheria were identified, with ages ranging from 4 to 41 years. Of the 12 cases that were under the age of 18 years, 9 (75%) were not fully immunized for diphtheria. The case fatality was 27%. Ninety-three household contacts, 981 school or work contacts and 595 healthcare worker contacts were identified and given prophylaxis against Corynebacterium diphtheriae infection. A targeted vaccination campaign for children aged 6–15 years was carried out at schools in the two districts. The outbreak highlighted the need to improve diphtheria vaccination coverage in the province and to investigate the feasibility of offering diphtheria vaccines to healthcare workers.

The wettability of several superhydrophobic surfaces that were prepared recently by simple, mostly single-step methods is described and compared with the wettability of surfaces that are less hydrophobic. We explain why two length scales of topography can be important for controlling the hydrophobicity of some surfaces (the lotus effect). Contact-angle hysteresis (difference between the advancing, θA, and receding, θR, contact angles) is discussed and explained, particularly with regard to its contribution to water repellency. Perfect hydrophobicity (θA/θR = 180°/180°) and a method for distinguishing perfectly hydrophobic surfaces from those that are almost perfectly hydrophobic are described and discussed. The Wenzel and Cassie theories, both of which involve analysis of interfacial (solid/liquid) areas and not contact lines, are criticized. Each of these related topics is addressed from the perspective of the three-phase (solid/liquid/vapor) contact line and its dynamics. The energy barriers for movement of the three-phase contact line from one metastable state to another control contact-angle hysteresis and, thus, water repellency.

The adsorption of poly(l-lysine) (PLL) from aqueous solution to poly(tetrafluoroethylene-co-hexafluoropropylene) (FEP) is investigated. Adsorption is controlled by choice of solvent (and PLL solution conformation) or by FEP surface chemistry. PLL adsorbs from pH 11 buffer solution to FEP: PLL adsorption is concomitant with the liberation of water molecules from the FEP-water interface resulting in a decreased interfacial free energy between organic and aqueous phases. PLL does not adsorb from an aqueous pH 7 solution to FEP unless the FEP surface is carboxylic acid-functionalized (FEPCO2H):an ionic interaction between FEP-carboxylate and PLL-ammonium enhances adsorption.

The surface modifications are charaterized by attenuated total reflectance infrared spectroscopy (ATR IR), ultraviolet-visible spectrophotometry (UV-vis), contact angle, and quantitatively by x-ray photoelectron spectroscopy (XPS). The adsorbed amount of PLL to FEP (from pH 11) is proportional to molecular weight whereas the adsorbed amount of PLL to FEP-CO2H (pH 7) is independent of molecular weight and likely proportional to surface charge density. The modified film samples (relative to the unmodified film samples) show improved characteristics in terms of wettability, chemical reactivity, adhesion, cell growth.

Thin dielectric films for optical applications are deposited on substrates using a variety of techniques including reactive sputtering, solgel reaction, and ion assisted plasma deposition. This transmission electron microscopy study characterizes optical coatings produced by the above deposition techniques and shows how changes in deposition conditions change microstructure and as a result the optical properties.