Neuroprotective Effects of Pituitary Adenylate Cyclase-Activating Polypeptide

Pituitary adenylate cyclase-activating polypeptide (PACAP) was first isolated from an ovine hypothalamus by Dr. Arimura and his colleagues in 1989 and demonstrated to be one of most conserved peptide through the different species. PACAP belongs to the secretin/glucagon/vasoactive intestinal peptide family and exists in a full form (PACAP-38) and a shorter form (PACAP-27). PACAP and its three different receptors, PAC1, VPAC1 andVPAC2, have been demonstrated in the central and peripheral nervous system. Furthermore, previous studies have proved that PACAP has pleiotropic functions, such as the regulation of neurodevelopment and protection against neuron apoptosis. The peptide exerts its physiological effects via PAC1, VPAC1 and VPAC2 receptors, which all belong to the class B, family of G protein-coupled receptors (GPCRs). The primary signaling pathways of PACAP receptors are cAMP mediated both PKA and MAPK pathways. The phospholipase D (PLD) and calcium signaling pathways can be activated by PACAP receptors as well.

Evidences from numbers of in vitro and in vivo experiments suggest that PACAP may enhance neuronal survival and neuronalregeneration in the nervous system. The cultured cerebellar granule cell, a model of programmed cell death, is widely used for investigation of the neuroprotective factors.

Beautiful Vibrations - Understand Phonons for Heat Transfer

As the most ubiquitous form of energy, thermal energy or simply heat is widely involved in almost every aspect of real-world applications. Better understanding and then “taming” the thermal transport processes inside various materials and devices, especially at the nanoscale, are critical to many fundamental and engineering problems. Tremendous researchopportunities are opened in this field, ranging from the large-scale recovery,storage, and conservation of heat, to improving the thermal safety and reliability of lithium-ion (Li-ion) batteries and electronic devices. Unrestricted to aeronautics and aerospace applications, many of these research topics will significantly change our everyday lives as well.

The advancement of cutting-edge heat transfer research is strongly dependent on the fundamental understanding of heat at the atomic level. In a dielectric material, heat is carried by the vibrations of atoms ormolecules, which are essentially sound waves. At each vibrational frequency, quantum mechanics principles dictate that the vibrational energy must be a multiple of a basic amount of energy, called a quantum.               

Chemical and Mineral Characteristics of Melted Snow-Water in the Jilin Province, North-East China

Atmospheric, as an important part of the ecosystem, has an important influence on the environment and ecology. Air pollution had become one of the environmental issues concerned widespread. The ecologicalenvironment had been affected by the particles in the atmosphere. Furthermore, particles were also harmful to the environment, cloud formation, atmosphere visibility, climate, and human health. Due to the relative large size, coarse particles generally precipitated to the ground through wet deposition. While fine particles still remained in the atmosphere for several weeks and could be transported through atmospheric circulation. 

Therefore, fine particles greatly impacted the environment. Understanding the physical and chemical properties of the particles in the snowfall is the most important prerequisite to investigate the impact of winter snowfall on the environment. Saxena and Ruggiero foundNa+, Cl-, SO42- and NO3- to be the predominant ions in precipitation atMcMurdo. Delmas reported sulfate, sodium, chloride, carbonaceous species and trace amounts of NH4+ and NO3- in precipitation on the Antarctic Plateau. Warburton and Linkletter found Na+, Mg2+, and K+ to be the predominant ions collected in snow on the Ross Ice Shelf. Mulvaneyand Wolff found low nitrate and sulfate, and high chloride concentrations in January ice core samples from the Weddell Sea sector of Antarctica.