Antimicrobial sand via adsorption of cationic Moringa oleifera protein

Moringa oleifera (Moringa) seeds contain a natural cationic protein (MOCP) that can be used as an antimicrobial flocculant for water clarification. Currently, the main barrier to using Moringa seeds for producing potable water is that the seeds release other water-soluble proteins and organic matter, which increase the concentration of dissolved organic matter (DOM) in the water. The presence of this DOM supports the regrowth of pathogens in treated water, preventing its storage and later use. A new strategy has been established for retaining the MOCP protein and its ability to clarify and disinfect water while removing the excess organic matter. The MOCP is first adsorbed and immobilized onto sand granules, followed by a rinsing step wherein the excess organic matter is removed, thereby preventing later growth of bacteria in the purified water. Our hypotheses are that the protein remains adsorbed onto the sand after the functionalization treatment, and that the ability of the antimicrobial functionalized sand (f-sand) to clarify turbidity and kill bacteria, as MOCP does in bulk solution, is maintained. The data support these hypotheses, indicating that the f-sand removes silica microspheres and pathogens from water, renders adhered Escherichia coli bacteria nonviable, and reduces turbidity of a kaolin suspension. The antimicrobial properties of f-sand were assessed using fluorescent (live-dead) staining of bacteria on the surface of the f-sand. The DOM that can contribute to bacterial regrowth was shown to be significantly reduced in solution, by measuring biochemical oxygen demand (BOD). Overall, these results open the possibility that immobilization of the MOCP protein onto sand can provide a simple, locally sustainable process for producing storable drinking water.     

The mechanostability of isolated focal adhesions is strongly dependent on pH

This report demonstrates that the mechanical stability of focal adhesions exhibits a biphasic and sensitive pH dependence. These studies used isolated focal adhesions, which retain many of the properties of the intracellular structures, including protein composition and force-dependent reinforcement by cytosolic proteins. The focal adhesion structures are least stable to applied force at a pH of 6.4, and significantly more stable at slightly higher and lower pH values. This trend is consistent with previous work that characterized the pH dependence of cell migration and may therefore be relevant to controlling the invasiveness of metastatic cancer cells. This approach is significant because it allows biochemical studies of large protein complexes previously studied only in cell culture, and therefore offers new opportunities for performing mechanistic studies of a range of factors that contribute to focal adhesion stability.     

A performance study of radio-opaque personal protective fabrics for the reduction of transmittance of gamma-rays and neutrons

Commercial radio-opaque combat (CRC) fabrics, for incorporation into personal protective equipment used by first responders and armed forces, are marketed as having the ability to provide a level of protection against specific types of radiation. For a CRC material, a standard combat uniform and a multi-layered chemical, biological, radiological, nuclear (CBRN) protective material, the present work examines chemical composition and radiation protection against gamma-rays and neutron fluxes. Significant reduction in gamma-ray transmittance occurs only for the CRC fabric (46–514 keV) with gamma-ray attenuation coefficients of 3.10 to <0.10 cm² g⁻¹. Reduction in neutron transmittance, for all three fabrics, could not be assessed with certainty as the measured transmittance was obscured by large statistical uncertainties.     

Characterizing dusky dolphin sounds from Argentina and New Zealand

Dusky dolphin (Lagenorhynchus obscurus) acoustic sounds were characterized by analyzing narrowband recordings [0-16 kHz in New Zealand (NZ) and 0-24 kHz in Argentina], and sounds in broadband recordings (0-200 kHz) were compared to their counterparts in down-sampled narrowband recordings (0-16 kHz). The most robust similarity between sounds present in broadband recordings and their counterparts in the down-sampled narrowband recordings was inter-click interval (ICI); ICI was therefore primarily used to characterize click sounds in narrowband recordings. In NZ and Argentina, distribution of ICIs was a continuum, although the distribution of ICIs in NZ had a somewhat bimodal tendency. In NZ, sounds that had smaller mean ICIs were more likely to have constant ICIs, and less likely to have increasing or decreasing ICIs. Similar to some other delphinids, dusky dolphins may use single, short duration sounds that have a constant ICI and closely spaced clicks for communication. No whistles were documented at either study site. Temporally structured sequences of burst pulses (i.e., sounds with ICI < about 10 ms) also occurred at both study sites, and these sequences contained 2-14 burst pulses that appeared closely matched aurally and in spectrograms and waveforms.     

Bemerkungen zur Homotopietheorie der Koinzidenzen mehrerer Abbildungen

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