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1. Structural Ensemble of the Insulin Monomer

   https://doi.org/10.1021/acs.biochem.1c00583  

   Busto-Moner, Luis; Feng, Chi-Jui; Antoszewski, Adam; Tokmakoff, Andrei; Dinner, Aaron R. (October 2021, Biochemistry)
2. The data universe of structural biology

   https://doi.org/10.1107/S205225252000562X  

   Berman, Helen M.; Vallat, Brinda; Lawson, Catherine L. (July 2020, IUCrJ)

   The Protein Data Bank (PDB) has grown from a small data resource for crystallographers to a worldwide resource serving structural biology. The history of the growth of the PDB and the role that the community has played in developing standards and policies are described. This article also illustrates how other biophysics communities are collaborating with the worldwide PDB to create a network of interoperating data resources. This network will expand the capabilities of structural biology and enable the determination and archiving of increasingly complex structures. 

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3. Structural organization of the spongy mesophyll

   https://doi.org/10.1111/nph.17971  

   Borsuk, Aleca M.; Roddy, Adam B.; Théroux‐Rancourt, Guillaume; Brodersen, Craig R. (February 2022, New Phytologist)

   Summary Many plant leaves have two layers of photosynthetic tissue: the palisade and spongy mesophyll. Whereas palisade mesophyll consists of tightly packed columnar cells, the structure of spongy mesophyll is not well characterized and often treated as a random assemblage of irregularly shaped cells.Using micro‐computed tomography imaging, topological analysis, and a comparative physiological framework, we examined the structure of the spongy mesophyll in 40 species from 30 genera with laminar leaves and reticulate venation.A spectrum of spongy mesophyll diversity encompassed two dominant phenotypes: first, an ordered, honeycomblike tissue structure that emerged from the spatial coordination of multilobed cells, conforming to the physical principles of Euler’s law; and second, a less‐ordered, isotropic network of cells. Phenotypic variation was associated with transitions in cell size, cell packing density, mesophyll surface‐area‐to‐volume ratio, vein density, and maximum photosynthetic rate.These results show that simple principles may govern the organization and scaling of the spongy mesophyll in many plants and demonstrate the presence of structural patterns associated with leaf function. This improved understanding of mesophyll anatomy provides new opportunities for spatially explicit analyses of leaf development, physiology, and biomechanics. 

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4. Structural Properties of the Stability of Jamitons

   https://doi.org/10.1007/978-3-030-66560-9_3  

   Ramadan, R. A.; Rosales, R. R.; Seibold, B. (December 2020, Mathematical Descriptions of Traffic Flow: Micro, Macro and Kinetic Models. SEMA SIMAI Springer Series)

   null; null (Ed.)

   It is known that inhomogeneous second-order macroscopic traffic models can reproduce the phantom traffic jam phenomenon: whenever the sub-characteristic condition is violated, uniform traffic flow is unstable, and small perturbations grow into nonlinear traveling waves, called jamitons. In contrast, what is essentially unstudied is the question: which jamiton solutions are dynamically stable? To understand which stop-and-go traffic waves can arise through the dynamics of the model, this question is critical. This paper first presents a computational study demonstrating which types of jamitons do arise dynamically, and which do not. Then, a procedure is presented that characterizes the stability of jamitons. The study reveals that a critical component of this analysis is the proper treatment of the perturbations to the shocks, and of the neighborhood of the sonic points. 

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5. Ensuring the Observability of Structural Test Obligations

   https://doi.org/10.1109/TSE.2018.2869146  

   Meng, Ying; Gay, Gregory; Whalen, Michael (September 2018, IEEE Transactions on Software Engineering)

   Test adequacy criteria are widely used to guide test creation. However, many of these criteria are sensitive to statement structure or the choice of test oracle. This is because such criteria ensure that execution reaches the element of interest, but impose no constraints on the execution path after this point. We are not guaranteed to observe a failure just because a fault is triggered. To address this issue, we have proposed the concept of observability—an extension to coverage criteria based on Boolean expressions that combines the obligations of a host criterion with an additional path condition that increases the likelihood that a fault encountered will propagate to a monitored variable. Our study, conducted over five industrial systems and an additional forty open-source systems, has revealed that adding observability tends to improve efficacy over satisfaction of the traditional criteria, with average improvements of 125.98% in mutation detection with the common output-only test oracle and per-model improvements of up to 1760.52%. Ultimately, there is merit to our hypothesis—observability reduces sensitivity to the choice of oracle and to the program structure. 

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