Hierarchical ZSM-11 with intergrowth structures:Synthesis,characterization and catalytic properties

Hierarchical ZSM-11 microspheres with intercrystalline mesoporous properties and rod-like crystals intergrowth morphology have been synthesized using a spot of tetrabutylammonium as a single template.XRD,FTIR,SEM,TEM and N2 adsorption analysis revealed that each individual particle was composed of nanosized rod crystals inserting each other and the intercrystalline voids existing among rods gave a significant mesopore size distribution.Steam treatment result demonstrated the excellent hydrothermal stability of samples.Various crystallization modes including constant temperature crystallization (one-stage crystallization) and two-stage temperature-varying crystallization with different 1st stage durations were investigated.The results suggested that the crystallization modes were mainly responsible for the adjustable particle size and textural properties of samples while the small amount of tetrabutylammonium bromide was mainly used to direct the formation of both ZSM-11 framework and its intergrowth morphology.Furthermore,the performance of optimal ZSM-11 as an active component for the catalytic pyrolysis of heavy oil was also investigated.Compared with the commercial pyrolysis catalyst,the hierarchical ZSM-11 catalyst exhibited a high selectivity to desired products(LPG+gasoline+diesel),as well as a much lower dry gas and coke yield,plus a high selectivity and yield of light olefins(C=3 C=4)and very poor selectivity to benzene.Therefore,fully open micropore-mesopore connectivity would make such hierarchically porous ZSM-11 zeolites very attractive for applications in clean petrochemical catalysis field.

Structural basis of signaling of cannabinoids receptors:paving a way for rational drug design in controling mutiple neurological and immune diseases

Cannabinoids(CBs),analgesic drugs used for thousands of years,were first found in Cannabis sativa,and the multiple CBs used medicinally,such as tetrahydrocannabinol(THC),cannabidiol(CBD)and dozens more,have complex structures.In addition to their production by plants,CBs are naturally present in the nerves and immune systems of humans and animals.Both exogenous and endogenous CBs carry out a variety of physiological functions by engaging with two CB receptors,the CB1 and CB2 receptors,in the human endocannabinoid system(ECS).Both CB1 and CB2 are G protein-coupled receptors that share a 7-transmembrane(7TM)topology.CB1,known as the central CB receptor,is mainly distributed in the brain,spinal cord,and peripheral nervous system.CB1 activation in the human body typically promotes the release of neurotransmitters,controls pain and memory learning,and regulates metabolism and the cardiovascular system.Clinically,CB1 is a direct drug target for drug addiction,neurodegenerative diseases,pain,epilepsy,and obesity.Unlike the exclusive expression of CB1 in the nervous system,CB2 is mainly distributed in peripheral immune cells.Selective CB2 agonists would have therapeutic potential in the treatment of inflammation and pain and avoid side effects caused by currently used clinical drugs.Although significant progress has been made in developing agonists toward CB receptors,efficient clinical drugs targeting CB receptors remain lacking due to their complex signaling mechanisms.The recent structural elucidation of CB receptors has greatly aided our understanding of the activation and signal transduction mechanisms of CB receptors.