Cellulose fibers-reinforced self-expanding porous composite with multiple hemostatic efficacy and shape adaptability for uncontrollable massive hemorrhage treatment.

Uncontrollable hemorrhage leads to high mortality and thus effective bleeding control becomes increasingly important in the military field and civilian trauma arena. However, current hemostats not only present limitation when treating major bleeding, but also have various side effects. Here we report a self-expanding porous composites (CMCP) based on novel carboxymethyl cellulose (CMC) fibers and acetalized polyvinyl alcohol (PVA) for lethal hemorrhage control. The CMC fibers with uniform fibrous structure, high liquid absorption and procoagulant ability, are evenly interspersed inside the composite matrix. The obtained composites possess unique fiber-porous network, excellent absorption capacity, fast liquid-triggered self-expanding ability and robust fatigue resistance, and their physicochemical performance can be fine-tuned through varying the CMC content. In vitro tests show that the porous composite exhibits strong blood clotting ability, high adhesion to blood cells and protein, and the ability to activate platelet and the coagulation system. In vivo hemostatic evaluation further confirms that the CMCP presents high hemostatic efficacy and multiple hemostatic effects in swine femoral artery major hemorrhage model. Additionally, the CMCP will not fall off from the injury site, and is also easy to surgically remove from the wound cavity after the hemostasis. Importantly, results of CT tomography and 3D reconstruction indicate that CMCP can achieve shape adaptation to the surrounding tissues and the wound cavities with different depths and shapes, to accelerate hemostasis while protecting wound tissue and preventing infection.

[Analysis and Optimization of the Temperature Retard between Sample and Air Based on Nucleic Acid Amplification System Heated by Air].

It is the main method for amplifying the specific gene to use the nucleic acid amplification system to accomplish polymerase chain reaction(PCR).The temperature retard between heat source and sample exists in the heating and cooling progresses of most nucleic acid amplification system.The retard would result in the problem that the sample would take a long time to reach the set temperature and the problem would reduce the speed of integrate reaction.Non-specific products would be created in the process of amplification when the sample cannot reach the set temperature within a certainly time and the amplified efficiency would be reduced.A miniaturization nucleic acid amplification system heated by air was designed in this study according to the principle of air-heated nucleic acid amplification system and the characteristics of the PCR instrument Smart-cycler.The heat transfer process was analyzed and the heat transfer time was calculated.The actual temperature was measured in real time,and the temperature curves were fitted.The heating time was chosen by analysis results and data fitting and the air temperature was changed,while the sample temperature was recorded.The retard between sample and air was optimized by choosing the best curve of sample temperature.The temperature retard between sample and air was reduced sharply and the required time of integrate progress is shortened to 50%.We confirmed from the amplification experiment of Listeria monocytogenes that the improved system could complete 3cycles within 4minutes,and the amplification effect was good.The amplification speed and effect could be improved effectively by optimizing the delay between sample and air.