Design and Modulation of Negative Thermal Expansion for Epoxy Polymers.

Modulating the coefficient of thermal expansion (CTE) and realizing low or negative thermal expansion (NTE) for epoxy polymers are challenging issues. In this study, we developed an effective strategy to prepare epoxy polymers with an NTE performance. A novel motif DBCOD-NH based on the dibenzocyclooctadiene (DBCOD) was designed, synthesized, and utilized as a curing agent for several commercial epoxy resins.

Interfacial Study of Steel Joints Prepared with a Catechol-Modified Epoxy Adhesive with Enhanced Bonding Performance and Durability.

Bonding is widely used in aircraft and vehicles due to its light weight and simple process, but its strength decreases sharply in hot and humid environments. Anodization treatment, used for enhancing aging performance, is environmentally harmful and unsuitable for steel. In this study, a catechol-modified epoxy adhesive (CMEA) was prepared on a hectogram scale.

Probing Interfacial Aging of Model Adhesion Joints under a Hygrothermal Environment at a Molecular Level.

Generally, for adhesive joints, the polar water molecules in humid environments can have a critical effect on the interfacial structures and structural evolution adjacent to the solid substrates. Regarding this, it is still a big challenge to detect and understand the interfacial hygrothermal aging process at the molecular level in real time and in situ. In this study, to trace the interfacial hygrothermal aging process of a classical epoxy formula containing diglycidyl ether of biphenyl A (DGEBA) and 2,2'-(ethylenedioxy) diethylamine (EDDA) with sapphire and fused silica in a typical hygrothermal environment (85 °C and 85% RH), sum frequency generation (SFG) vibrational spectroscopy was used to probe the molecular-level interfacial structural change over the time.

Caveolae and the oxidative stress response.

Oxidative stress is a feature of many disease conditions. Oxidative stress can activate a number of cellular pathways leading to cell death, including a distinct iron-dependent pathway involving lipid peroxidation, termed ferroptosis, but cells have evolved complex mechanisms to respond to these stresses. Here, we briefly summarise current evidence linking caveolae to the cellular oxidative stress response.

Caveolae sense oxidative stress through membrane lipid peroxidation and cytosolic release of CAVIN1 to regulate NRF2.

Caveolae have been linked to many biological functions, but their precise roles are unclear. Using quantitative whole-cell proteomics of genome-edited cells, we show that the oxidative stress response is the major pathway dysregulated in cells lacking the key caveola structural protein, CAVIN1. CAVIN1 deletion compromised sensitivity to oxidative stress in cultured cells and in animals.

Multicolor Mechanochromic Epoxy Thermosets That Recognize the Intensity, Type, and Duration of Mechanical Stimulation.

Mechanochromic polymers that exhibit multiple color changes under external mechanical stimulation show great potential for sensor applications. Herein, an epoxy thermoset that can reveal the intensity, type, and duration of mechanical stimulation via a combination of disulfide (DS) and rhodamine (Rh) mechanochromophores is reported. A unique multicolor transition occurs upon ball mill or manual grinding because of the different activation energies of DS and Rh.

Spectroscopically Detecting Molecular-Level Bonding Formation between an Epoxy Formula and Steel.

The formation of the interfacial adhesion between an epoxy adhesive and a substrate was normally accompanied by the epoxy curing process on the substrate. Although the debate on the formation mechanism of the interfacial adhesion is still ongoing, this issue can causally be resolved by studying the interfacial structural formation between the epoxy adhesive and the substrate. Herein, to reveal the interfacial structural formation of a representative formula composed of epoxy (digylcidyl ether of biphenyl A, DGEBA) and amine hardener (2,2'-(ethylenedioxy) diethylamine, EDDA) with the steel substrate upon curing and postcuring treatments, sum-frequency generation (SFG) vibrational spectroscopy with a sandwiched transparent window/epoxy adhesive/steel setup was applied to detect and track the buried molecular-level structures at the epoxy adhesive/steel interface.

Molecular-Level Correlation between Spectral Evidence and Interfacial Bonding Formation for Epoxy Adhesives on Solid Substrates.

Interfacial bonding strength of an epoxy-based adhesive depends on the interfacial interaction between the adhesive and the substrate. Normally, the curing process at the interface accompanied by the interfacial bonding formation is different from that in the bulk, and it is still a big challenge to probe the interfacial bonding formation at a molecular level. In this study, to trace the interfacial structural evolution of a representative formula of epoxy (digylcidyl ether of biphenyl A, DGEBA) and amine hardener [1,2-bis(2-aminoethoxy)ethane, EDDA] with the sapphire and silica substrates upon curing and post-curing steps, sum frequency generation (SFG) vibrational spectroscopy is employed to detect the molecular-level interfacial structural information.

Cavin3 released from caveolae interacts with BRCA1 to regulate the cellular stress response.

Caveolae-associated protein 3 (cavin3) is inactivated in most cancers. We characterized how cavin3 affects the cellular proteome using genome-edited cells together with label-free quantitative proteomics. These studies revealed a prominent role for cavin3 in DNA repair, with BRCA1 and BRCA1 A-complex components being downregulated on cavin3 deletion.

An inverted CAV1 (caveolin 1) topology defines novel autophagy-dependent exosome secretion from prostate cancer cells.

CAV1 (caveolin 1) expression and secretion is associated with prostate cancer (PCa) disease progression, but the mechanisms underpinning CAV1 release remain poorly understood. Numerous studies have shown CAV1 can be secreted within exosome-like vesicles, but antibody-mediated neutralization can mitigate PCa progression; this is suggestive of an inverted (non-exosomal) CAV1 topology. Here we show that CAV1 can be secreted from specific PCa types in an inverted vesicle-associated form consistent with the features of bioactive CAV1 secretion.

Caveolae: Formation, dynamics, and function.

Caveolae are abundant surface pits formed by the assembly of cytoplasmic proteins on a platform generated by caveolin integral membrane proteins and membrane lipids. This membranous assembly can bud off into the cell or can be disassembled releasing the cavin proteins into the cytosol. Disassembly can be triggered by increased membrane tension, or by stress stimuli, such as UV.

Identification of intracellular cavin target proteins reveals cavin-PP1alpha interactions regulate apoptosis.

Caveolae are specialized domains of the plasma membrane. Formation of these invaginations is dependent on the expression of Caveolin-1 or -3 and proteins of the cavin family. In response to stress, caveolae disassemble and cavins are released from caveolae, allowing cavins to potentially interact with intracellular targets.

Structure-controlled Co-Al layered double hydroxides/reduced graphene oxide nanomaterials based on solid-phase exfoliation technique for supercapacitors.

High-efficient nanosheets exfoliation and ordered controlled stacking are in urgent need of work for electrochemistry application. Here, we have developed a high-efficient and environmentally-friendly solid-phase method for the exfoliation of Co-Al layered double hydroxide (Co-Al LDH) and graphene oxide (GO). Meanwhile, we found that there is a dynamic structure evolution in the self-assembly process between Co-Al LDH-NS and GO-NS and new theoretical structure models were proposed.

Controlled Self-Assembled NiFe Layered Double Hydroxides/Reduced Graphene Oxide Nanohybrids Based on the Solid-Phase Exfoliation Strategy as an Excellent Electrocatalyst for the Oxygen Evolution Reaction.

Layered double hydroxides (LDHs), as an effective oxygen evolution reaction (OER) electrocatalyst, face many challenges in practical applications. The main obstacle is that bulk materials limit the exposure of active sites. At the same time, the poor conductivity of LDHs is also an important factor.

Rapid Stress Relaxation and Moderate Temperature of Malleability Enabled by the Synergy of Disulfide Metathesis and Carboxylate Transesterification in Epoxy Vitrimers.

Vitrimers make up a class of polymeric materials combining the advantages of thermosets and thermoplastics, because they can be reprocessed while being at the same time permanently cross-linked. However, a long heating duration or an elevated temperature is necessary for most vitrimers to relax the stress from deformation and exhibit malleability. Herein, a disulfide-containing carboxylic acid is applied as a curing agent to synthesize epoxy vitrimers with simultaneous disulfide metathesis and carboxylate transesterification.

Bio-inspired semi-transparent silver nanowire conductor based on a vein network with excellent electromechanical and photothermal properties.

A bio-inspired conductive binary-network of vein-silver nanowires (AgNWs) was embedded in poly(dimethylsiloxane) (PDMS) to prepare a semi-transparent stretchable conductor (vein-AgNWs-PDMS) by a simple dipping process. The special conductive structure was constructed by using veins with a porous structure as an ideal skeleton to load AgNW networks, which allowed the vein-AgNWs-PDMS composite to show a low sheet resistance of 1 Ω sq with 74% transmittance. The figure of merit of vein-AgNWs-PDMS is as high as 2502 and can be adjusted easily by controlling the times of the dipping cycle.

Rational Design of Peptide-Functionalized Poly(Methacrylic Acid) Brushes for On-Chip Detection of Protease Biomarkers.

There is an increasing demand for developing new materials and approaches for rapid and sensitive detection of protease biomarkers. Herein, the poly(methacrylic acid) (PMAA) brushes were synthesized from silica nanoparticles via surface-initiated atom transfer radical polymerization (ATRP), and flexibly functionalized with different fluorescein-labeled peptides, serving as the substrates for protease assay. To facilitate the point-of-care detection of protease, polyacrylamide gel pad arrays were fabricated to allow permeation of fluorescein-labeled peptide fragments cleaved from the PMAA brushes.

MDM2 promotes epithelial-mesenchymal transition and metastasis of ovarian cancer SKOV3 cells.

Background: Metastasis accounts for the most lethal reason for the death of ovarian cancer patients, but remains largely untreated. Epithelial-mesenchymal transition (EMT) is critical for the conversion of early-stage ovarian tumours into metastatic malignancies. Thus the exploration of the signalling pathways promoting EMT would open potential opportunities for the treatment of metastatic ovarian cancer.

Versatile Functionalization of Poly(methacrylic acid) Brushes with Series of Proteolytically Cleavable Peptides for Highly Sensitive Protease Assay.

The development of new materials for fast and sensitive protease assay is in demand for timely diagnosis of diseases, such as cardiovascular disease, cancers, and Alzheimer disease. Herein, poly(methacrylic acid) (PMAA) brushes were synthesized from the surfaces of silica nanoparticles via surface-initiated atom transfer radical polymerization (ATRP), and functionalized with series of proteolytically cleavable peptides for highly sensitive protease assay. Upon the proteolytic cleavage of the peptides, a short peptide fragment with fluorescent tag (GGK-FITC) is released to the solution, which can be easily detected with a benchtop fluorescence microscope.

Optically binary liquid crystalline blue phases induced by one-armed cholesterol-linked azobenzene molecules.

A series of one-armed cholesterol-linked azobenzene molecules named CholXAzo with different spacers were synthesized, in which Chol6Azo was found to have induced blue phases (BPs) with a concentration of 4.0 wt%. Under irradiation of 385 nm UV light with a density of 15.

Nutlin-3 inhibits epithelial-mesenchymal transition by interfering with canonical transforming growth factor-β1-Smad-Snail/Slug axis.

Enormous efforts have been made to explore small molecules that interfere with the TGF-β signaling pathway, so as to inhibit EMT and the cancer metastasis, but few agents have been identified. In this study, we demonstrated that Nutlin-3 could abolish the down-regulation of E-cadherin induced by TGF-β1 in p53-deficient cancer cells. Further studies revealed that Nutlin-3 prohibited EMT by blocking the phosphorylation of Smad2/3, resulting in the decreased transcription of Snail/Slug.

Luminescence of Eu(DBM)3Phen-doped in azobenzene-containing copolymers--effects of absorption overlapping of two components.

Poly(N-isopropylacrylamide)-b-poly[6-[4-(4-methylphenyl-azo)phenoxy]hexylmethacrylate] (PNIPAM(32)-b-PAzoMM(8)) and poly(N-isopropylacrylamide)-b-poly[6-[methyl(4-nitrophenyldiazenyl)phenyl]aminohexylmethacrylate] (PNIPAM(32)-b-PAzoNO(10)) were prepared by reversible addition-fragmentation chain transfer (RAFT) radical polymerization. The optical properties of Eu(DBM)(3)Phen (Eu, Europium; DBM, dibenzoylmethide; Phen, 1,10-phenanthroline)-doped azobenzene-containing copolymer vesicle solutions were studied by UV-vis and fluorescence spectroscopy. When the electronic transition bands of azobenzene and Eu(DBM)(3)Phen overlapped at about 350 nm in PNIPAM(32)-b-PAzoMM(8), the fluorescent emission intensity at 612 nm of Eu(DBM)(3)Phen could be modulated by irradiation with UV and visible light.

[A control study of a school-based life skills education on prevention of behavior problems in third-grade schoolchildren].

Objective: To evaluate the effectiveness on the prevention of behavior problems of life skills education combining school-based and parent-involved approaches for third-grade students in China.

Methods: This research was targeted at the population of third-grade children in two elementary schools in Qinhuangdao City, Hebei Province. Nine regular school classrooms were randomly divided into three groups: the intervention group (n=208), internal control group (n=209) and external control group (n=204).