SSR Marker Technique and Its Application on Chinese Bayberry( Myrica rubra,Myricaceae)

SSR marker technique was summarized from the aspects of types and genetic characteristics of SSR loci, principles and characteristics of SSR technique, and development of SSR markers. The literatures about the applications of SSR markers on germplasm studies of Chinese bayberry were reviewed to provide a refer- ence for related studies.

Molecular Marker Techniques Using Single Primers and Their Advances

Molecular marker techniques have been widely applied in the fields of genetic diversity analysis,germplasm resources identification,molecular fingerprint and genetic linkage map construction,QTL mapping and molecular assisted breeding.On the basis of stating the concept of molecular marker techniques based on single primer amplification reactions,this study focused on the sorting and induction of single-primer molecular marker techniques,and expounded their derivative development.Finally,the application prospect and future expectation of single-primer molecular marker techniques were described in detail.The purpose of this study was to clarify the types of molecular marker techniques based on single primer amplification reactions,so that researchers can quickly and conveniently select molecular marker techniques according to their own specific scientific research conditions.

3D visualization of the material flow in friction stir welding process

The material flow in friction stir welded 2014 Al alloy has been investigated using a marker insert technique （MIT）. Results of the flow visualization show that the material flow is asymmetrical during the friction stir welding （FSW） process and there are also significant differences in the flow patterns observed on advancing side and retreating side. On advancing side, some material transport forward and some move backward, but on retreating side, material only transport backward. At the top surface of the weld, significant material transport forward due to the action of the rotating tool shoulder. Combining the data from all the markers, a three-dituensional flow visualization, similar to the 3D image reconstruction technique, was obtained. The three-dimensional plot gives the tendency chart of material flow in friction stir welding process and from the plot it can be seen that there is a vertical, circular motion around the longitudinal axis of the weld. On the advancing side of the weld, the material is pushed downward but on the retreating side, the material is pushed toward the crown of the weld. The net result of the two relative motions in both side of the advancing and the retreating is that a circular motion comes into being. Comparatively, the material flow around the longitudinal axis is a secondary motion.

Mitral valve cleft gapping mechanism in functional mitral regurgitation:An in-vitro study

Background and aim:Gapping formation of the mitral valve cleft is unknown.The objective of this study was to quantify the geometry of mitral valve cleft coaptation in the asymmetric and symmetric papillary muscles(PMs)positions in a dilated annulus in order to reveal mitral valve gapping mechanism.Methods:Nine fresh porcine mitral valves with the posterior leaflet clefts were sutured onto a saddle-shaped dilated annulus in an in-vitro experiment to simulate mitral valve closure at hydrostatic pressure.PMs were adjusted to the normal position,and subsequently to positions of asymmetric and symmetric PM displacement.Sonomicrometry was used to measure positions of the lateral and medial clefts.Results:PM displacement tethered the leaflets.Both the opening angle and contact angle of the lateral cleft,but not of the medial cleft,increased in the asymmetric PM displacement.Neither the opening angle nor contact angle of both clefts increased in the symmetric PM displacement.Conclusions:Displacement of the postero-medial PM moves the posterior leaflet medially and impairs coaptation of the lateral cleft,but not medial cleft,which suggest that the medial cleft displacement in the asymmetric PM position is another mechanism of gap formation in addition to leaflet tenting due to apical leaflet displacement.Symmetric PM displacement cause leaflet tenting,but doesn’t impair the leaflet cleft coaptation,which suggest that the asymmetric PM position is even worse than the symmetric PM position.