Microbes in indoor environments are constantly being exposed to antimicrobial surface finishes. Many are rendered non‐viable after spending extended periods of time under low‐moisture, low‐nutrient surface conditions, regardless of whether those surfaces have been amended with antimicrobial chemicals. However, some microorganisms remain viable even after prolonged exposure to these hostile conditions. Work with specific model pathogens makes it difficult to draw general conclusions about how chemical and physical properties of surfaces affect microbes. Here, we explore the survival of a synthetic community of non‐model microorganisms isolated from built environments following exposure to three chemically and physically distinct surface finishes. Our findings demonstrated the differences in bacterial survival associated with three chemically and physically distinct materials. Alkaline clay surfaces select for an alkaliphilic bacterium, Kocuria rosea, whereas acidic mold‐resistant paint favors Bacillus timonensis, a Gram‐negative spore‐forming bacterium that also survives on antimicrobial surfaces after 24 hours of exposure. Additionally, antibiotic‐resistant Pantoea allii did not exhibit prolonged retention on antimicrobial surfaces. Our controlled microcosm experiment integrates measurement of indoor chemistry and microbiology to elucidate the complex biochemical interactions that influence the indoor microbiome.

The decades-long global trend of urbanization has led to a population that spends increasing amounts of time indoors. Exposure to microbes in buildings, and specifically in dust, is thus also increasing, and has been linked to various health outcomes and to antibiotic resistance genes (ARGs). These are most efficiently screened using DNA sequencing, but this method does not determine which microbes are viable, nor does it reveal whether their ARGs can actually disseminate to other microbes. We have thus performed the first study to: 1) examine the potential for ARG dissemination in indoor dust microbial communities, and 2) validate the presence of detected mobile ARGs in viable dust bacteria. Specifically, we integrated 166 dust metagenomes from 43 different buildings. Sequences were assembled, annotated, and screened for potential integrons, transposons, plasmids, and associated ARGs. The same dust samples were further investigated using cultivation and isolate genome and plasmid sequencing. Potential ARGs were detected in dust isolate genomes, and we confirmed their placement on mobile genetic elements using long-read sequencing. We found 183 ARGs, of which 52 were potentially mobile (associated with a putative plasmid, transposon or integron). One dust isolate related to Staphylococcus equorum proved to contain a plasmid carrying an ARG that was detected metagenomically and confirmed through whole genome and plasmid sequencing. This study thus highlights the power of combining cultivation with metagenomics to assess the risk of potentially mobile ARGs for public health.

Since the advent of soap, personal hygiene practices have revolved around removal, sterilization, and disinfection—both of visible soil and microscopic organisms—for a myriad of cultural, aesthetic, or health‐related reasons. Cleaning methods and products vary widely in their recommended use, effectiveness, risk to users or building occupants, environmental sustainability, and ecological impact. Advancements in science and technology have facilitated in‐depth analyses of the indoor microbiome, and studies in this field suggest that the traditional “scorched‐earth cleaning” mentality—that surfaces must be completely sterilized and prevent microbial establishment—may contribute to long‐term human health consequences. Moreover, the materials, products, activities, and microbial communities indoors all contribute to, or remove, chemical species to the indoor environment. This review examines the effects of cleaning with respect to the interaction of chemistry, indoor microbiology, and human health.

A versatile system has been designed and fabricated to prepare atom-probe field-ion-microscope (APFIM) specimens in a systematic manner, such that internal interfaces can be positioned in the tips of these wire specimens for subsequent analysis of their chemical composition. This system incorporates both beaker electrolytic and zone electrolytic cell configurations, a specially constructed power supply, and a special transmission electron microscope holder for wires. The power supply enables ac electroetching or dc electropolishing in the automated or manual modes. The ac wave forms available are sine (0.002 Hz–200 kHz) or square (10 Hz–20 kHz). Triggering and gating are performed manually or with a pulse generator. The dc output is gated manually to produce a continuous output or with a pulse generator to produce single pulses with widths in the range 50 μs–1 s. A counter indicates the number of periods of voltage applied, and the total charge transferred in the electrolytic cell is integrated in the range 10 μA s–1 kA s. The power supply provides 0 to ±48 V peak at 1 A peak. A double-tilt stage for an Hitachi H-700H 200 kV transmission electron microscope (TEM) was radically modified to hold APFIM specimens; this stage is vibrationless at 310 000× magnification. It has a tilting range of ±30° and ±27° for the x and y tilts, respectively. Examples are given of the controlled backpolishing of W-3 at. % Re, W-25 at. % Re, Mo-5.4 at. % Re, and Fe-3 at. % Si specimens, and their observation by TEM, to selectively place grain boundaries in the tip region. The analysis of the chemical composition of a grain boundary, which is first located in a W-25 at. % Re specimen via TEM, by the APFIM technique is presented.

Using a two-zone thallium vapor transport furnace and a thick film ink process, we have successfully made superconducting films 10 to 50 pm thick on a variety of substrates. Ba2Ca2Cu3OX and Bi0.22Sr1.6Ba0,4Ca2Cu30x precursor films with and without Ag additions were made by mixing powders in an organic vehicle, painting a substrate and burning the vehicle off. Films were converted to the superconducting phase by passing an 0 2 carrier gas over a T12O3 source and then the sample. TBCCO 1223 films generally form over a narrow sample temperature range near 86OoC, whereas TBSBCCO films form 1212,1223 or a mixture of these phases depending on sample annealing temperature and 0 2 partial pressure. TBCCO T,'s average 104K with zero-field Jc(77K)=3500 A/cm2* while TBSBCCO T i s are higher at llOK with Jc=6800 A/cm2. Both compounds show weak-link behavior in a magnetic field.