Synthesis of Indeno[1′,2′:4,5]imidazo[1,2‑<i>a</i>]pyridin-11-ones and Chromeno[4′,3′:4,5]imidazo[1,2‑<i>a</i>]pyridin-6-ones through Palladium-Catalyzed Cascade Reactions of 2‑(2-Bromophenyl)imidazo[1,2‑<i>a</i>]pyridines

A novel and efficient synthesis of 11<i>H</i>-indeno­[1′,2′:4,5]­imidazo­[1,2-<i>a</i>]­pyridin-11-one, a hybrid structure of indenone with imidazo­[1,2-<i>a</i>]­pyridine, from the reaction of 2-(2-bromophenyl)­imidazo­[1,2-<i>a</i>]­pyridine with carbon monoxide through palladium-catalyzed CO insertion and C–H bond activation, has been developed. Intriguingly, under similar conditions but in the presence of Cu­(OAc)₂, the reaction selectively afforded 6<i>H</i>-chromeno­[4′,3′:4,5]­imidazo­[1,2-<i>a</i>]­pyridin-6-one, a hybrid structure of chromenone with imidazo­[1,2-<i>a</i>]­pyridine, via a more sophisticated cascade process including acetoxylation, deacetylation, CO insertion, and C–H bond activation

Memory-enhanced neural network control of piezoelectric actuators with a rate-amplitude-dependent hysteresis model

Due to the presence of strong hysteresis nonlinearity, achieving robust and precise control of piezoelectric actuators (PEAs) is highly challenging. In this article, a novel rate-amplitude-dependent asymmetric Prandtl-Ishlinskii (RADAPI) model is proposed for modeling the hysteresis nonlinearity in PEAs and ultimately used for feedforward control based on its inverse model. Then, an uncertainty and disturbance estimator (UDE)-based controller using radial basis function (RBF) neural network is developed to address the issue of integral windup. To overcome the issue of passive knowledge forgetting, the selective memory recursive least squares weight update law is adopted. Moreover, the stability of the closed-loop system is demonstrated. A combined control scheme, incorporating RADAPI hysteresis inverse model feedforward compensation along with RBF-UDE based closed-loop feedback control, is devised to enhance the trajectory tracking accuracy of PEAs. Both theoretical analysis and experimental results are provided to validate the proposed control scheme.</p

Selective Access to 3‑Cyano‑1<i>H</i>‑indoles, 9<i>H</i>‑Pyrimido[4,5‑<i>b</i>]indoles, or 9<i>H</i>‑Pyrido[2,3‑<i>b</i>]indoles through Copper-Catalyzed One-Pot Multicomponent Cascade Reactions

Novel and selective synthetic approaches toward indole derivatives via copper-catalyzed one-pot multicomponent cascade reactions of 1-bromo-2-(2,2-dibromovinyl)­benzenes with aldehydes and aqueous ammonia are presented. Intriguingly, the concentration of ammonia, the molar ratio of reagents, and the structural features of the aldehyde substrate serve as key factors in controlling the selective formation of 3-cyano-1<i>H</i>-indoles, 9<i>H</i>-pyrimido­[4,5-<i>b</i>]­indoles, or 9<i>H</i>-pyrido­[2,3-<i>b</i>]­indoles. Compared with literature procedures, the synthetic approaches reported herein have advantages such as readily available starting materials, mild reaction conditions, and divergent reaction patterns toward different products with easily tunable selectivity

Correlation Between the Computed Tomography and 3D Scanning System-Based Periorbital Morphology of Children with Congenital Microphthalmia

This article aimed to explore the correlation between the periorbital morphology determined using a 3D scanning system and CT in congenital microphthalmia. Fifty-two children with microphthalmia aged 0–6 were enrolled in this study. All the participants were subjected to orbital CT scans and 3D scanning. The CT and 3D scanning images were separately processed to obtain the orbital and facial parameters. Multivariate regression was used to analyze the correlation between 3D parameters and orbital volume. The orbital volume of the affected side (15.25 ± 3.35 cm3) was generally smaller than the unaffected side (18.58 ± 2.65 cm3, p 2 = 0.808, p  The retarded orbital volume could be estimated by the parameters based on 3D scanning, along with axial length. In the follow-up stage, 3D scanning can be a novel alternative method to assess the degree of orbital growth retardation in congenital microphthalmia.</p

Absolute and cumulative variation for the principal component analysis on shape, BMD and combined shape/BMD models.

<p>Absolute and cumulative variation for the principal component analysis on shape, BMD and combined shape/BMD models.</p

Statistical modeling of the equine third metacarpal bone incorporating morphology and bone mineral density

<div><p>The objective of this study was to describe the three-dimensional shape and subchondral bone mineral density (BMD) variation of the equine distal third metacarpal bone (MC3) using a statistical shape model. The association between form and function builds upon previous two-dimensional observations of MC3 epiphyseal structure. It was expected that the main source of variation would be an increase in overall MC3 bone size, correlated to an increase in subchondral BMD. Geometry and bone mineral density was obtained from CT image data of 40 healthy Thoroughbred horses. This was used to create a statistical shape model, in which the first ten components described 75% of the variation in geometry and BMD. The first principal component described an increase in overall size of the MC3 distal epiphysis, coupled with higher BMD on the disto-palmar and dorso-proximal surfaces. The second component was qualitatively described as an increased convexity of the sagittal ridge at the dorsal junction of the epiphysis and the metaphysis, coupled to increased BMD in that region. The third component showed an increase in lateral condylar surface area relative to medial condylar area. As the condyle reduced in relative surface area, the BMD at both dorsal condyles increased. The statistical shape analysis produced a compact description of 3-D shape and sub-chondral bone mineral density variation for the third metacarpal bone. This study uniquely illustrates the shape variations in a sample population of MC3 bones, and the corresponding changes in subchondral BMD.</p></div

Reconstruction error of geometry and apparent BMD with increasing principal components.

<p>Reconstruction error of geometry and apparent BMD with increasing principal components.</p

Workflow to generate a statistical shape model of the MC3 bone using CT imaging data.

<p>Workflow to generate a statistical shape model of the MC3 bone using CT imaging data.</p

Initial estimates of third metacarpal bone shape and parameters to quantify changes observed in the principal component analysis, the segmented point cloud from the original CT data is included as a reference.

<p>Large blue points indicate anatomical landmarks identified from a template mesh and subsequently fit to the population to measure morphological parameters.</p

Proteolytic Characteristics of Cathepsin D Related to the Recognition and Cleavage of Its Target Proteins

<div><p>Cathepsin D (CD) plays an important role in both biological and pathological processes, although the cleavage characteristics and substrate selection of CD have yet to be fully explored. We employed liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify the CD cleavage sites in bovine serum albumin (BSA). We found that the hydrophobic residues at P1 were not only a preferential factor for CD cleavage but that the hydrophobicity at P1’ also contributed to CD recognition. The concept of hydrophobic scores of neighbors (HSN) was proposed to describe the hydrophobic microenvironment of CD recognition sites. The survey of CD cleavage characteristics in several proteins suggested that the HSN was a sensitive indicator for judging the favorable sites in peptides for CD cleavage, with HSN values of 0.5–1.0 representing a likely threshold. Ovalbumin (OVA), a protein resistant to CD cleavage in its native state, was easily cleaved by CD after denaturation, and the features of the cleaved peptides were quite similar to those found in BSA, where a higher HSN value indicated greater cleavability. We further conducted two-dimensional gel electrophoresis (2DE) to find more proteins that were insensitive to CD cleavage in CD-knockdown cells. Based on an analysis of secondary and three-dimensional structures, we postulated that intact proteins with a structure consisting of all α-helices would be relatively accessible to CD cleavage.</p></div