Synaptosomal-associated protein 29 (SNAP29) encodes a member of the SNARE family of proteins implicated in numerous intracellular protein trafficking pathways. SNAP29 maps to the 22q11.2 region and is deleted in 90% of patients with 22q11.2 deletion syndrome (22q11.2DS). Moreover, bi-allelic SNAP29 mutations in patients are responsible for CEDNIK (cerebral dysgenesis, neuropathy, ichthyosis, and keratoderma) syndrome. A mouse model that recapitulates abnormalities found in these syndromes is essential for uncovering the cellular basis of these disorders. In this study, we report that mice with a loss of function mutation of Snap29 on a mixed CD1;FvB genetic background recapitulate skin abnormalities associated with CEDNIK, and also phenocopy neurological and ophthalmological abnormalities found in CEDNIK and a subset of 22q11.2DS patients. Our work also reveals an unanticipated requirement for Snap29 in male fertility and supports contribution of hemizygosity for SNAP29 to the phenotypic spectrum of abnormalities found in 22q11.2DS patients.
The three-dimensional unsteady turbulent flow of rotational flow self-priming pump was simulated by using Reynolds time-averaged N-S equations and the standard k-ε turbulent model, sliding mesh model of static-dynamic coupled models and SIMPLE arithmetic. The static pressure distribution of the pump central rotative surface and relative velocity of the impeller central rotative surface in a complete application cycle were analyzed. The rule of instantaneous head in a impeller channel cycle was studied, and the positions of maximal head and minimal head were analyzed. It revealed that the unsteady method can truly simulate the changes of the rotational flow self-priming pump interior flow, and the unsteady characteristic of interior flow in rotational flow self-priming pump is obvious and it changes as the relative position of impeller and volute change. The change is periodical, and its frequency is relate to the impeller number and the rotate speed of the pump.
The structure and working principle are introduced in the paper. Based on the physical model of key parts to roto-jet pump which is set up in Gambit, the 3-D steady flows numerical simulation has been implemented by means of Fluent under design operating conditions. This method could avoid the error in simulating single part of the pump. The result shows the interflow distribution of the pump, the difference effect is very well after installing short blades on impeller. the shape of collecting pipe has little impact on the pressure within rotor cavity and the vertex band is apt to form in the corner of the collecting pipe inlet. By analyzing the energy losses between two different installed types of roto-jet pump. The result shows that the energy loss of rotor cavity in right-closed impeller pump is more than in the left-open impeller pump, but the effect of impeller pressurization in left-open impeller pump is not well, the energy loss caused by collecting pipe is almost the same in the two different pumps. The analyzing results can provide some proposals for structure reforming, performance and efficiency improving.
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