Objective To assess the changes of humidity and ammonia concentration in rat and mouse individually ventilated cages (IVC) based on macroenvironmental humidity and air ventilation changes .Methods Three kinds of rat and mouse IVC in barrier facilities were set as research objective .The changes of micronvironmental humidity and ammonia concentration at 40 times/h and 60 times /h air changes were detected continuously for a 7-days-cycle relative to low (40%), moderate (50%), and high (60%) macroenvironmental humidity.Results Mouse and rat IVC with 40 times /h air changes under low macroenvironmental humidity condition , mouse IVC with 40 times/h and rat IVC with 60 times/h air changes under moderate macroenvironmental humidity condition , mouse IVC with 60 times /h air changes under high macroenvironmental humidity condition , basically meet the GB14925-2010 requirements.While under macroenvironmental high humidity condition, the microenvironments of rat and mouse IVC with 60 times/h air changes could not satisfy the requirements.Conclusions The environmental humidity and ventilation frequency are the key index of IVC microenvironment.Only on the basis of external environment conditions to set up reasonable IVC ventilation frequency in order to better maintain the IVC microenvironment so that to achieve the goal of effective management .

Existing neuroregulatory techniques can achieve precise stimulation of the whole brain or cortex, but high-focus deep brain stimulation has been a technical bottleneck in this field. In this paper, based on the theory of negative permeability emerged in recent years, a simulation model of magnetic replicator is established to study the distribution of the induced electric field in the deep brain and explore the possibility of deep focusing, which is compared with the traditional magnetic stimulation method. Simulation results show that a single magnetic replicator realized remote magnetic source. Under the condition of the same position and compared with the traditional method of stimulating, the former generated smaller induced electric field which sharply reduced with distance. By superposition of the magnetic field replicator, the induced electric field intensity could be increased and the focus could be improved, reducing the number of peripheral wires while guaranteeing good focus. The magnetic replicator model established in this paper provides a new idea for precise deep brain stimulation, which can be combined with neuroregulatory techniques in the future to lay a foundation for clinical application.
Brain ; Cerebral Cortex ; Computer Simulation ; Electricity ; Magnetic Fields