Molecular rearrangement of pyrazino[2,3-c]quinolin-5(6H)-ones during their reaction with isocyanic acid

A new tetrahydropyrazino[2,3-c]quinolin-5(6H)-ones were prepared from 3-chloroquinoline-2,4(1H,3H)-diones and ethylene diamine. In their reaction with HNCO, an unprecedented molecular rearrangement produced new types of hydantoin derivatives. All prepared compounds are characterized using their 1H, 13C, and 15N NMR spectra and the results of the X-ray analysis are also presented. A proposed mechanism of rearrangement is discussed in this essay.

Nonlinear Finite Element Modelling of Thermo-Visco-Plastic Styrene and Polyurethane Shape Memory Polymer Foams

This paper presents nonlinear finite element (FE) models to predict time- and temperature-dependent responses of shape memory polymer (SMP) foams in the large deformation regime. For the first time, an A SMP foam constitutive model is implemented in the ABAQUS FE package with the aid of a VUMAT subroutine to predict thermo-visco-plastic behaviors. A phenomenological constitutive model is reformulated adopting a multiplicative decomposition of the deformation gradient into thermal and mechanical parts considering visco-plastic SMP matrix and glass microsphere inclusions. The stress split scheme is considered by a Maxwell element in parallel with a hyper-elastic rubbery spring. The Eyring dashpot is used for modelling the isotropic resistance to the local molecular rearrangement such as chain rotation. A viscous flow rule is adopted to prescribe shear viscosity and stress. An evolution rule is also considered for the athermal shear strengths to simulate macroscopic post-yield strain-softening behavior. In order to validate the accuracy of the model as well as the solution procedure, the numerical results are compared to experimental responses of Styrene and Polyurethane SMP foams at different temperatures and under different strain rates. The results show that the introduced FE modelling procedure is capable of capturing the major phenomena observed in experiments such as elastic and elastic-plastic behaviors, softening plateau regime, and densification.

Computer-aided design of PVR mutants with enhanced binding affinity to TIGIT

Background TIGIT, as a novel immune checkpoint molecule involved in T cell and NK cell anergy, could induce the immune tolerance and escape through binding with its ligand PVR. Blockade of TIGIT/PVR is considered as a promising strategy in cancer immunotherapy. However, to facilitate the design of inhibitors targeting TIGIT/PVR, the structural characteristics and binding mechanism still need to be further studied. Methods In this study, molecular dynamics (MD) simulations and in silico mutagenesis were used to analyze the interaction between TIGIT and its ligand PVR. Then, PVR mutants were designed and their activities were determined by using TIGIT overexpressed Jurkat cells. Results The results suggested that the loops of PVR (CC′ loop, C′C″ loop, and FG loop) underwent a large intra-molecular rearrangement, and more hydrogen bond crosslinking between PVR and TIGIT were formed during MD simulations. The potential residues for PVR to interact with TIGIT were identified and utilized to predict high affinity PVR mutants. Through the biological activity evaluation, four PVR mutants (PVRS72W, PVRS72R, PVRG131V and PVRS132Q) with enhanced affinity to TIGIT were discovered, which could elicit more potent inhibitory effects compared with the wild type PVR. Conclusions The MD simulations analysis provided new insights into the TIGIT/PVR interaction model, and the identified PVR mutants (PVRS72W, PVRS72R, PVRG131V and PVRS132Q) could serve as new candidates for immunotherapy to block TIGIT/PVR.

Inflammatory markers in the nasal mucosa and polyp-modified tissues in chronic rhinosinusitis with nasal polyps

Introduction. To date, chronic rhinosinusitis with nasal polyps (CRSwNP) has not yet been extensively studied: the molecular factors and mechanisms involved in the initiation of polypous transformations in nasal mucosa (NM) and sustaining their recurrence probability are still to be determined. Simultaneously, it is necessary to understand the molecular rearrangement in NM tissues to make clinical prognosis and choose an adequate therapeutic or surgical strategy for CRSwNP treatment. The aim of the study was to identify the features of how inflammatory markers localize and are distributed in the NM and polyps in various morphological CRSwNP types. Materials and methods. We studied morphological and chemical structure of nasal polyps and mucosa of the inferior turbinates. The material was obtained during surgical management of patients diagnosed with CRSwNP. The comparison group involved the patients with a deviated septum who underwent septorhi-noplasty and had neither polyposis nor concomitant inflammatory/allergic pathology. The NM removed in surgeries was used to compare morphological and chemical changes. Immunohistochemistry was applied to determine the localization and distribution of SP, NK1, nNOS, iNOS, and IL1b in the tissues. Results. The formation of nasal polyps was found to be accompanied by morphological and chemical altera-tions in the mucous membrane of the inferior turbinates. In polyps of different morphological types, the changes in the activity of inflammatory markers were specific. Conclusion. The data obtained indicate that changes in the NM of the inferior turbinates, which accompany polyposis development, give certain pathological causes that induce and maintain the pathological process. We have revealed the features of the specific signaling microenvironment in the nasal cavity, which provide special conditions for the formation of polyps of various types. The specificity of the activity and distribu-tion of inflammatory markers in the polyps of different morphological types may serve as a prerequisite for the development of personalized therapy for the disease. Keywords: chronic rhinosinusitis with nasal polyps, inflammation, neurokinin receptors, substance P, nitric oxide

Cocrystal Engineering of Molecular Rearrangement: A “Turn-On” Approach for High Performance N type Organic Semiconductor

Developing novel high-performance n-type semiconductors is of great importance for the future organic electronics. The complicated synthesizing procedures of new electron deficient backbones or chemical modification to control the energy...

A Fabric-Based Textile Stretch Sensor for Optimized Measurement of Strain in Clothing

Fabric stretch sensors are available as planar fabrics, but their reliability and reproducibility are low. To find a good working setup for use in an elastic sports garment, the design of such sensors must be optimized. The main purpose of this study was to develop resistive strain sensors from stretchable conductive fabric and investigating the influence of stretchability on conductivity/resistivity. The influence of using the sensor in a sweat rich environment was also determined, in order to evaluate the potential use of the sensor in sporting garments. The sensor resistivity performance was analyzed for its sensitivity, working range, and repeatability and it was determined what makes the sensitivity when elongated or stretched. The resistivity was found to decrease with elongation if no sweat is present, this can be due to molecular rearrangement and a higher degree of orientation that improves the conductivity of a material. The result from this finding also shows that for wearable applications the commercial EeonTexTM conductive stretchable fabric did not show a considerable resistivity increase, nor a good sensitivity. The sensitivity of the sensor was between 0.97 and 1.28 and varies with different elongation %. This may be due to the mechanical deformation characteristics of knitted samples that lead to changes in conductivity. We advise that the testing performed in this paper is done by default on new stretch sensitive textile materials, so practical use of the material can be correctly estimated.