1. A Maximum Caliber analysis of the Foldon Hypothesis
Eric Johnson Proteins. 2022 May;90(5):1170-1178. doi: 10.1002/prot.26299. Epub 2022 Jan 22.
Different models of protein folding favor different mechanisms. Some models rely on a defined pathway, while other models rely on a more heterogeneous set of pathways. The Foldon Hypothesis is based on the concept of a defined pathway. According to the Foldon Hypothesis, protein folding is characterized by the stepwise assembly of small, cooperative units called foldons. The Maximum Caliber (Max Cal) method provides an opportunity to test this model. The Max Cal method gives the probabilities for dynamical trajectories, in much the same way that the maximum entropy principle gives the probabilities for equilibrium states. In this study, the Max Cal method was applied to folding data for the protein cytochrome c (cyt c; Hu W, Kan ZY, Mayne L, Englander SW. Proc Natl Acad Sci U S A. 2016;113:3809-3814). The overall picture to emerge from this analysis is that the data do not require a dominant, defined pathway. The folding of cytochrome c is likely a heterogeneous process that includes multiple pathways.
2. The usefulness of the maximum Hounsfield units (HU) in predicting the shockwave lithotripsy outcome for ureteral stones and the proposal of novel indicators using the maximum HU
Yusuke Sugino, Takahiro Kato, Shigeru Furuya, Takeshi Sasaki, Kiminobu Arima, Yoshiki Sugimura Urolithiasis. 2020 Feb;48(1):85-91. doi: 10.1007/s00240-019-01123-3. Epub 2019 Mar 11.
Computed tomography (CT) attenuation value of ureteral stones is one of the predictors of shockwave lithotripsy (SWL) outcome. It is common to use the mean Hounsfield units (HU) to describe the CT attenuation value. However, an observer bias can occur when measuring the mean HU in the conventional method. On the other hand, our way to obtain only the maximum HU is simpler and less biased. We retrospectively evaluated 464 patients with ureteral stones who underwent SWL and compared predictive accuracy of various factors including maximum and mean HU. Results were determined after a single SWL. Predictors of SWL success were examined by the statistical analysis of successful and failed groups. 324 of the 464 patients who underwent SWL were stone-free after a single SWL. Significant differences were found in factors related to CT attenuation value and stone size. As a result of receiver operating characteristic analysis, it was found that maximum HU and mean HU, major diameter and volume have equivalent prediction accuracy, respectively. Multivariate analysis revealed that maximum HU and major diameter were included in independent predictors. We also examined the new original indicators using maximum HU and major diameter. Stone-resistant probability obtained from the logistic model and Maximum HU and Major diameter Index obtained by multiplying maximum HU by major diameter were useful for predicting SWL success, respectively. In conclusion, maximum HU and mean HU have equivalent predictive accuracy, and maximum HU is easier to measure and less biased than mean HU.
3. 3-(9H-Fluoren-9-yl)-1,3-diphenyl-propan-1-one
Fu Feng, Zhi-Cai Cui, Xin-Ping Liu, Wei-Bing Hu Acta Crystallogr Sect E Struct Rep Online. 2012 Oct 1;68(Pt 10):o2858. doi: 10.1107/S1600536812032497. Epub 2012 Sep 5.
In the title compound, C(28)H(22)O, the fluorene ring system is approximately planar [maximum deviation = 0.044 (2) Å] and forms dihedral angles of 69.88 (6) and 89.46 (6)° with the phenyl rings. The crystal packing is stabilized by weak π-π stacking inter-actions, with centroid-centroid distances of 3.7172 (13) and 3.7827 (11) Å.
