Synthesis, performance and structure characterization of glyoxal-monomethylolurea-melamine (G-MMU-M) co-condensed resin

In order to reduce the formaldehyde emission of formaldehyde-based wood adhesive from the source,it is aimed to develop a novel co-condensed resin of glyoxal-monomethylolurea-melamine(G-MMU-M).A series of G-MMU-M resins with various formulations of raw materials were successfully prepared.The basic properties and bonding performance of the G-MMU-M resins were determined.Furthermore,the structures of resins were characterized by FTIR,^(13)C NMR,XPS,and ESI-MS.The results show that the prepared G-MMU-M resin remains stable for 30 d,meanwhile,the dry and wet bonding strength of the plywoods bonded with the resins,solid content and viscosity are influenced greatly by the addition amount of melamine and MMU/G molar ratio.The G-MMU-M resins with MMU/G molar ratio of 0.9:1.0 and 8% melamine exhibit the highest dry and bonding strength of 1.98 MPa and 1.27 MPa,increased by 34% and 63%,respectively,in comparison with glyoxal-monomethylolurea(G-MMU)resin.In the G-MMU-M resins,there were four main oligomers including M—CH(—^(+)CH-MMU)-O-MMU,M-CH(—CH_(2)OH)-MMU-O-MMU,M—CH(—OH)—^(+)CH-MMU-O-MMU,and M—CH(—^(+)CH-MMU)-MMU-p-G.

Apoptotic extracellular vesicles are metabolized regulators nurturing the skin and hair

Over 300 billion of cells die every day in the human body,producing a large number of endogenous apoptotic extracellular vesicles(apoEVs).Also,allogenic stem cell transplantation,a commonly used therapeutic approach in current clinical practice,generates exogenous apoEVs.It is well known that phagocytic cells engulf and digest apoEVs to maintain the body’s homeostasis.In this study,we show that a fraction of exogenous apoEVs is metabolized in the integumentary skin and hair follicles.Mechanistically,apoEVs activate the Wnt/β-catenin pathway to facilitate their metabolism in a wave-like pattern.The migration of apoEVs is enhanced by treadmill exercise and inhibited by tail suspension,which is associated with the mechanical force-regulated expression of DKK1 in circulation.Furthermore,we show that exogenous apoEVs promote wound healing and hair growth via activation of Wnt/β-catenin pathway in skin and hair follicle mesenchymal stem cells.This study reveals a previously unrecognized metabolic pathway of apoEVs and opens a new avenue for exploring apoEV-based therapy for skin and hair disorders.

Multiplexed imaging detection of live cell intracellular changes in early apoptosis with aggregation-induced emission fluorogens

Apoptosis is an important process for maintaining tissue homeostasis and eliminating abnormal cells in multicellular organisms.Abnormality in apoptosis often leads to severe diseases such as cancers. Better understanding of its mechanisms and processes is therefore important. Accompanying molecular biology events of apoptosis is a series of cellular morphology changes: nucleus condensation, cell shrinkage and rounding, cell surface blebbing, dynamic blebbing, apoptotic membrane protrusions and nucleus fragmentations and finally, the formation and release of apoptotic bodies. It is difficult to detect cellular changes in the early phase of apoptosis due to the subtle changes at this phase. In the current study, we induced apoptosis in He La cells with H2 O2 and used nuclear dye Hoechst 33258, mitochondria, lysosome and cytoplasmic protein specific aggregation-induced emission fluorogens(AIEgens), TPE-Ph-In, 2 M-DABS and BSPOTPE to successfully perform live cell multiplexed imaging to investigate early apoptosis cellular events. We showed the gradual dissipation of mitochondria membrane potential until it is nondetectable by TPE-Ph-In. Increased mitophagy detected by TPE-Ph-In and 2 M-DABS, condensed nucleus detected by Hoechst33258, increased permeability and/or reduced integrity of nuclear membrane, and increased intracellular vesicles detected by2 M-DABS are some of the early events of apoptosis.

Smart luminescent solar concentrator as a BICPV window

Building integrated concentrating photovoltaic(BICPV)windows have attracted numerous studies in recent years.However,there is a tradeoff between the light transmittance and power generation efficiency in the design of BICPV window.In this paper,a smart luminescent solar concentrator(LSC)is introduced as the BICPV window.The proposed smart LSC system features on the combination of fluorescent dyes with thermochromic materials to enhance photoelectric conversion efficiency as well as form a dynamic response mechanism to ambient solar radiation and environmental temperature.In this study,a BICPV smart window system consists of the waveguide doped with organic dye Lumogen F Red-305(BASF)and the thermochromic hydrogel membrane has been developed.The research on analytic design parameters is executed through optical simulation by ray tracing technology along with outdoor comparative experiments.From simulations for a smart LSC of 100 mm×100 mm×3 mm with a bottom-mounted solar cell of 100 mm×10 mm,the optical effective concentration is found to be with the range of 1.23 to 1.31 when a highest gain of 1.26 in power over the bare solar cell is obtained from experiments.

Bioinspired Hydrogels with Muscle-Like Structure for AIEgen-Guided Selective Self-Healing

Living systems,including human beings,animals,and plants,display the power to self-heal spontaneously after being damaged.The self-healing is usually selective,which means that the healing efficiency is related to the spatial distribution of dynamic interfacial interactions of the two rupturing surfaces.Current artificial systems use noncovalent interactions or dynamic covalent bonds to prepare self-healing materials.However,they can only show nonselective self-healing due to their homogeneous internal structures.Herein,we report the construction of a composite hydrogel Gel-C consisting of three different self-healing hydrogels(Gel-Y,Gel-G,and Gel-O)through the use of classic bilayer hydrogel technology.When the composite hydrogel was cut into two pieces,the relative orientation of the parts was rotated through different angles to study the differences in self-healing.Owing to the heterogeneous internal structure of the composite hydrogel and the recognition specificity of each included hydrogel,the interfacial dynamic interactions distribution of the two rupturing surfaces is diverse.The results of tensile tests demonstrated that these rotated samples exhibited different self-healing efficiencies.This system realized the transformation of artificial materials from nonselective self-healing to selective selfhealing,providing inspiration for the development of novel biological materials and engineering materials.