Abstract: There is provided a ferritic lightweight steel which contains 2.0 to 3.0 wt % manganese (Mn), 5.0 to 6.0 wt % aluminum (Al) and 0.1 to 0.3 wt % carbon (C) and has a tensile strength of 900 MPa to 1,108 MPa. The lightweight steel includes ferrite-austenite dual grains as a result of performing low-temperature tempering-induced partitioning (LTP) at 300° C. for 10 minutes after isothermal annealing.

Abstract: The present invention provides a microjet drug injection device equipped with a backflow prevention valve, the microjet drug injection device comprising an upper housing, a lower housing, a partition, and the backflow prevention valve provided with a slit through which a drug passes at a lower end and allowing the drug to move only towards an injection nozzle.

Abstract: In a needleless syringe according to the present invention, a current is supplied to a solenoid coil to generate a magnetic field so as to move a moving magnetic body and a piston forward, and when the current to the solenoid coil is cut off, an elastic member for the moving magnetic body moves the moving magnetic body backward and an elastic member for the piston moves the piston backward, so that the piston to be injected by pressurizing a drug is configured to reciprocate repeatedly forward and backward and thus, a predetermined drug can be repeatedly injected at high speed. In addition, according to the present invention, time for which the current is applied to the solenoid coil, is adjusted to minimize recoil without adding a recoil offset structure so that the structure is simple and convenience of use can be improved.

Abstract: The present invention provides a microjet drug injection device equipped with a backflow prevention valve, the microjet drug injection device comprising an upper housing, a lower housing, a compartment, and a backflow prevention valve.

Abstract: Non-activated tissue-regeneration polypeptides (TRPs) and their preparation methods are disclosed. The TRPs include: a protein transduction domain (PTD) making the polypeptides to permeate a cell membrane without cell membrane receptors; a furin activation domain (FAD) which has at least one proprotein convertase cleavage site and which can be cleaved by the proprotein convertase and activate a tissue regeneration domain (TRD) in cells; and a tissue regeneration domain (TRD) which can be activated by the proprotein convertase cleavage of the FAD to stimulate the growth or formation of tissues or to induce the regeneration of tissues. The TRPs can be mass-produced by cultured bacteria, such as recombinant E. coli, are in a non-activated state before in vivo administration, and their separation, purification, handling, storage and administration are simple and convenient.

Abstract: The present invention relates to non-activated Wnt inhibition polypeptides (WIPs) containing: (a) a protein transduction domain (PTD) which enables said WIPs to permeate a cell membrane without the aid of a cell membrane receptor; and (b) a Wnt antagonist domain which is inactive by itself, but is activated in mammalian cells and then secreted out of the cells to function to inhibit Wnt signal transduction. Also, the invention relates to a method for preparing said non-activated WIPs, and a pharmaceutical composition containing said WIPs as active ingredients. Said non-activated WIPs can be produced in large quantities through the culture of bacteria such as E coli., and are biochemically inactive before being administered into the human body, and thus the production cost thereof is only one several tenths of that of previously known active proteins (sFRPs, DKKs, etc.