Investigating the Effect of Chain Extender on the Phase Separation and Mechanical Properties of Polybutadiene-Based Polyurethane.

The thermodynamic incompatibility between the soft and hard segments of thermoplastic polyurethane (TPU) results in a microphase-separated behavior and excellent mechanical properties. However, the effect of the chain extender on the degree of microphase separation (DMS) and the resultant mechanical properties of TPU have not been well studied because of the complex interactions between the soft and hard segments. Herein, hydroxyl-terminated polybutadiene-based TPUs(HTPB-TPUs) without hydrogen bonding between the soft and hard segments are synthesized using hydroxyl-terminated polybutadiene, toluene diisocyanate, and four different chain extenders, and the effect of the chain extender structure on DMS is analyzed experimentally using a combination of analytical techniques.

Strong Triel Bonds with Be as Electron Donor.

A systematic theoretical study was conducted on the triel bonds (TrBs) within the TrX···Be(CO) complexes (Tr = B, Al, Ga, In, Tl; X = H, F, Cl, Br, I). The interaction energies of these systems range between 4 and 38 kcal/mol. The TrB weakens as X becomes more electronegative in the B and Al systems, while the opposite pattern of stronger bonds is observed in the In and Tl analogues.

Triel Bonds between BH/CHBX and M(MDA) (X = H, CN, F, CH, NH; M = Ni, Pd, Pt, MDA = Enolated Malondialdehyde) and Group 10 Transition Metal Electron Donors.

A systematic theoretical study was conducted on the triel bonds (TrB) within the BH∙∙∙M(MDA) and CHBX∙∙∙M(MDA) (M = Ni, Pd, Pt, X = H, CN, F, CH, NH, MDA = enolated malondialdehyde) complexes, with BH and CHBX acting as the electron acceptors and the square-coordinated M(MDA) acting as the electron donor. The interaction energies of these systems range between -4.71 and -33.

C∙∙∙O and Si∙∙∙O Tetrel Bonds: Substituent Effects and Transfer of the SiF Group.

The tetrel bond (TB) between 1,2-benzisothiazol-3-one-2-TF-1,1-dioxide (T = C, Si) and the O atom of pyridine-1-oxide (PO) and its derivatives (PO-X, X = H, NO, CN, F, CH, OH, OCH, NH, and Li) is examined by quantum chemical means. The Si∙∙∙O TB is quite strong, with interaction energies approaching a maximum of nearly 70 kcal/mol, while the C∙∙∙O TB is an order of magnitude weaker, with interaction energies between 2.0 and 2.

Fabrication of Polyurethane Elastomer/Hindered Phenol Composites with Tunable Damping Property.

Vibration and noise-reduction materials are indispensable in various fields. Polyurethane (PU)-based damping materials can dissipate the external mechanical and acoustic energy through molecular chain movements to mitigate the adverse effects of vibrations and noise. In this study, PU-based damping composites were obtained by compositing PU rubber prepared using 3-methyltetrahydrofuran/tetrahydrofuran copolyether glycol, 4,4'-diphenylmethane diisocyanate, and trimethylolpropane monoallyl ether as raw materials with hindered phenol, viz.

Triel Bonds with Au Atoms as Electron Donors.

The novel triel bonds of BX (X=H, F, Cl, Br, and I) and C H B as electron acceptors and AuR (R=Cl and CH ) as an electron donor were explored. The triel bond is a primary driving force for most complexes, while the contribution from a halogen-chlorine interaction in BX -AuCl (X=Cl, Br, and I) and an iodine-Au interaction in BI -Au(CH ) is also very important. Interestingly, the positively charged Au atom of AuCl can attractively bind with the holes of BX and C H B.

Polyurethanes Based on Polylactic Acid for 3D Printing and Shape-Memory Applications.

Polylactic acid (PLA) has received increased attention in the development of shape-memory polymers and biomedical materials owing to its excellent physical properties and good biocompatibility and biodegradability. However, the inherent brittleness and high shape-recovery temperature of this material limit its application in the human body. Herein, we fabricated a PLA-based thermoplastic polyurethane (PLA-TPU) prepared from modified PLA-diol, dicyclohexylmethane-4,4'-diisocyanate, and 1,4-butanediol to solve the limitations of pure PLA.

A more secure and effective method for throat swab collection: The importance of adequate exposure of oral cavity in COVID-19 specimen collection.

Objectives: This study aims to propose a novel and effective throat swab collection method for coronavirus disease 2019 (COVID-19).

Methods: The subjects were randomly divided into two groups. The subjects were asked to open their mouth to make "ah" sound (traditional method) or simulate yawn (improved method) for throat swab collection.

Enhanced cell proliferation and osteogenic differentiation in electrospun PLGA/hydroxyapatite nanofibre scaffolds incorporated with graphene oxide.

One of the goals of bone tissue engineering is to mimic native ECM in architecture and function, creating scaffolds with excellent biocompatibility, osteoinductive ability and mechanical properties. The aim of this study was to fabricate nanofibrous matrices by electrospinning a blend of poly (L-lactic-co-glycolic acid) (PLGA), hydroxyapatite (HA), and grapheme oxide (GO) as a favourable platform for bone tissue engineering. The morphology, biocompatibility, mechanical properties, and biological activity of all nanofibrous matrices were compared.

Interleukin-17A promotes the formation of inflammation in the lung tissues of rats with pulmonary fibrosis.

The aim of the present study was to investigate the effects of interleukin (IL)-17A in a rat model of pulmonary fibrosis. In total, 20 female Wistar rats were randomly divided into a normal saline (NS group) and a bleomycin group (BLM group). The BLM group rats were intratracheally instilled with BLM, while the NS group rats were intratracheally instilled with saline.

Meta-analysis of concurrent chemoradiotherapy in the treatment of locoregionally advanced nasopharyngeal carcinoma.

Background: With radiotherapy (RT) alone, the five-year overall survival (OS) rate for advanced nasopharyngeal carcinoma (NPC) can only reach 40%, the ratio of distant metastasis (DM) is 36-40%. This meta-analysis was performed to compare the clinical efficacy of concurrent chemoradiotherapy (CCRT) with RT alone in the treatment of locoregionally advanced NPC.

Methods: The related literature were retrieved and reviewed by two independent investigators from the followed electronic databases: Review manager 5.