Design and performance of polyurethane elastomers composed with different soft segments

Thermoplastic polyurethane elastomers (TPUs) are widely used in a variety of applications as a result of flexible and superior performance. However, few scholars pay close attention on the design and synthesis of TPUs through the self‐determined laboratory process, especially on definite of chemical structures and upon the influence on properties. To investigate the properties of synthesized modifier based on chemical structure, firstly each kind of unknown structure and composition ratio of TPUs was determined by using a new method. Furthermore, the thermal characteristics and mechanical properties of modifiers were exposed by thermal characteristics and mechanics performance tests. The experimental results indicate that TPUs for use as an asphalt modifier can successfully be synthesized with the aid of semi‐prepolymer method. The linear backbone structure of TPUs with different hard segment contents were determined by micro test methods. The polyester‐based TPUs had thermal behavior better than the polyether-based TPUs; conversely, the low temperature performance of polyether‐based TPUs was superior. Most importantly, it was found that the relative molecular mass of TPUs exhibited a weak effect on the mechanical properties, whereas the crystallinity of hard segment showed a significant influence on the properties of TPUs

5-(1H-Indol-3-yl­methyl­idene)-2,2-di­methyl-1,3-dioxane-4,6-dione

In the title compound, C15H13NO4, the conjugated double-bond system between the two rings adopts a cis configuration and there is an intra­molecular indole–ketone C—H⋯O inter­action. The indole N—H group forms an inter­molecular hydrogen bond with a ketone O-atom acceptor, giving a chain structure along the ab direction. The O-heterocyclic ring adopts a boat conformation and makes a dihedral angle of 16.72 (6)° with the indole ring system

2,2-Dimethyl-5-[(2-nitro­anilino)methyl­idene]-1,3-dioxane-4,6-dione

The crystal of the title compound, C13H12N2O6, contains a bifurcated intra­molecular hydrogen bond between the N—H group and one of the O atoms from both the nitro group and the dioxane-4,6-dione moiety. In addition, mol­ecules are linked by a series of inter­molecular C—H⋯O secondary inter­actions. The dihedral angles between the benzene ring and the nitro group and the conjugated part of the dioxane-4,6-dione moiety are 19.1 (2) and 17.89 (7)°, respectively

Interplay of quantum phase transition and flat band in hybrid lattices

We investigate the interplay of superradiant phase transition (SPT) and energy band physics in an extended Dicke-Hubbard lattice whose unit cell consists of a Dicke model coupled to an atomless cavity. We found in such a periodic lattice the critical point that occurs in a single Dicke model becomes a critical region that is periodically changing with the wavenumber $k$. In the weak-coupling normal phase of the system we observed a flat band and its corresponding localization that can be controlled by the ground-state SPT. Our work builds the connection between flat band physics and SPT, which may fundamentally broaden the regimes of many-body theory and quantum optics.Comment: 9 pages, 5 figures, published versio

Interplay of quantum phase transition and flat band in hybrid lattices

We establish a connection between quantum phase transitions (QPTs) and energy band theory in an extended Dicke-Hubbard lattice, where the periodical critical curves modulated by wave number k leads to rich equilibrium dynamics. Interestingly, the chiral-symmetry-protected flat band and the localization that it engenders exclusively occurs in the normal phase and disappears in the superradiant phase. This originates from the QPT induced simultaneous breaking up of the on-site resonance condition and off-site chiral symmetry of the system, which prohibits the destructive interference for obtaining a flat band. Our work offers an approach to identify different phases of the lattice via detecting the flat bands or simply the related localizations in a single cell, and, in turn, to control the appearance of flat bands by QPT

N-Cyclo­hexyl-4-[(2-nitro­anilino)­meth­yl]thio­phene-2-sulfonamide

In the title compound, C17H21N3O4S2, an intra­molecular N—H⋯O hydrogen bond involving the proximate amine and nitro groups is observed. In the crystal, inter­molecular N—H⋯O hydrogen bonds involving the amine and SO2 groups occur. One of the notro O atoms is disordered over two conformations with occupancies of 0.578 (12) and 0.422 (12)

An Overview of Systematic Reviews of Chinese Herbal Medicine for Parkinson's Disease

Parkinson's disease (PD) is a high prevalence neurodegenerative disorder without a disease-modifying therapy. Up to now, a number of systematic reviews have been conducted to evaluate efficacy and safety of Chinese herbal Medicine (CHM) for PD patients. Here, we aimed to assess the methodological quality and reporting quality of systematic reviews using an overview, and then synthesize and evaluate the available evidence level of CHM for PD. Six databases were searched from inception to September 2018. The literatures were selected and data were extracted according to prespecified criteria. A Measurement Tool to Assess Systematic Reviews (AMSTAR) was used to evaluate the quality of methodology, and Grading of Recommendations Assessment, Development, and Evaluation (GRADE) to determine the evidence quality of the primary outcome measures. A total of 11 systematic reviews with 230 RCTs of CHM for PD were included. AMSTAR scores of the included reviews were range from 4 to 9. Compared with conventional western medicine (WCM), CHM paratherapy showed significant effect in improving UPDRS score, Webster scale score, PDQ-39, NMSQuest, CHM Syndrome Integral Scale, and PDSS. However, CHM monotherapy showed no difference relative to WCM according to various outcome measures. Adverse events were reported in 9 systematic reviews. The side effect in CHM paratherapy group was generally less than or lighter than that in WCM group. The quality of the evidence of primary outcomes was moderate (42%) to high (54%) according to the GRADE profiler. The present finding supported the use of CHM paratherapy for PD patients but we should treat the evidence cautiously because of the methodological flaws, whereas there is insufficient evidence of CHM monotherapy for PD