![]() Huffman: One thing I’ve said over the years in my forensic work is I’ve never encountered a failure that occurred because of just one design or construction flaw. Q: For a less experienced engineer or inspector, what are some things that could be easily missed? And if we saw a water stain, we would probably want to investigate further because it could be a simple condensate leak from a pipe, or it could be symptomatic of a bigger issue. Water is not a good thing to get into the building envelope. We look for evidence of water penetration in the building. We look for excessive deflection on floors. With structural, particularly we would look for cracks, the things that Jeff had flagged about doors not opening, that would be picked up as structural as well. Is site rainwater directed away from the building, or is it collected at the building? If it’s collected at the building you have the potential for water affecting the subgrade soil under the building’s foundations. Spriggs: One aspect of a property that has an influence on both structural and geotechnical concerns is site water. That typically means we’re looking at a geotechnical foundation issue. And of course, if it’s masonry, you’re going to start seeing 45 degree cracks coming off the top of doors and other wall openings. Huffman: From a geotechnical standpoint, it typically is going to revolve around doors and windows that don’t work and cracks that people are noticing. Q: From your respective fields, what are things you would look for in building inspections? If you see something with your powers of observation that doesn’t make sense or looks different than it has been for years, you can be the one to start the process to get someone who is professionally qualified on-site to perform an inspection. Now anyone can take the first step of an inspection. Rather, it needs to be somebody with professional engineering or architect credentials. ![]() Building Inspectors are trained in building code compliance, not in the design of structures nor do they have experience with how changed conditions affect a structure. Jeff Huffman: A building inspector or building official is not necessarily the right person for the structural inspection. Building inspectors employed by localities, who many people may think of immediately, are often not the right expert to inspect an existing structure as they generally have not been trained in forensic investigations. ![]() But if you’re looking for an investigation of possible settlement on a building, you might call a structural engineer or a geotechnical engineer because you have questions of the water table, soil quality, things that might have changed over the course of time. If you’re interested in mold remediation or just a mold study, you’re going to call an environmental specialist for that. ![]() Our findings provide a fundamental understanding of the ion-mediated structural responsiveness of DNA origami at the nanoscale enabling applications under a wide range of ionic conditions.Q: Who is qualified to perform building inspections?ĭave Spriggs: That depends on what you’re looking for. This reconfigurability occurs in an ion type- and concentration-specific manner. ![]() Moreover, we found that poorly assembled nanostructures at low ion concentrations undergo substantial self-repair upon ion addition in the absence of free staple strands. We then manipulated fully folded constructs by exposing them to unfavorable ionic conditions that led to the emergence of substantial disintegrity but not to unfolding. We determined the conditions for highly efficient DNA origami folding in the presence of several mono- (Li +, Na +, K +, Cs +) and divalent (Ca 2+, Sr 2+, Ba 2+) ions, expanding the range where DNA origami structures can be exploited for custom-specific applications. Using atomic force microscopy and Förster resonance energy transfer (FRET) spectroscopy down to the single-molecule level, we report on the global and local structural performance and responsiveness of DNA origami constructs following self-assembly, upon post-assembly ion exchange and post-assembly ion-mediated reconfiguration. Here, we harness a wide range of mono- and divalent ions to control the structural features of DNA origami constructs. However, the ion–DNA interplay and the resulting ion-specific structural integrity and responsiveness of DNA constructs are underexploited. Electrostatic screening of the negative charges of nucleic acids is essential for their folding and stability thus, ions play a critical role in nucleic acid self-assembly in both biology and nanotechnology. Nucleic acid-based biomolecular self-assembly enables the creation of versatile functional architectures. ![]()
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