Rodent incisors are covered by enamel only on their labial side. This asymmetric distribution of enamel is instrumental to making the cutting edge sharp. Enamel matrix is secreted by ameloblasts derived from dental epithelium. Here we show that overexpression of follistatin in the dental epithelium inhibits ameloblast differentiation in transgenic mouse incisors, whereas in follistatin knockout mice, ameloblasts differentiate ectopically on the lingual enamel-free surface. Consistent with this, in wild-type mice, follistatin was continuously expressed in the lingual dental epithelium but downregulated in the labial epithelium. Experiments on cultured tooth explants indicated that follistatin inhibits the ameloblast-inducing activity of BMP4 from the underlying mesenchymal odontoblasts and that follistatin expression is induced by activin from the surrounding dental follicle. Hence, ameloblast differentiation is regulated by antagonistic actions of BMP4 and activin A from two mesenchymal cell layers flanking the dental epithelium, and asymmetrically expressed follistatin regulates the labial-lingual patterning of enamel formation.

The tumor suppressor gene Apc (adenomatous polyposis coli) is a member of the Wnt signaling pathway that is involved in development and tumorigenesis. Heterozygous knockout mice for Apc have a tumor predisposition phenotype and homozygosity leads to embryonic lethality. To understand the role of Apc in development we generated a floxed allele. These mice were mated with a strain carrying Cre recombinase under the control of the human Keratin 14 (K14) promoter, which is active in basal cells of epidermis and other stratified epithelia. Mice homozygous for the floxed allele that also carry the K14-cre transgene were viable but had stunted growth and died before weaning. Histological and immunochemical examinations revealed that K14-cre–mediated Apc loss resulted in aberrant growth in many ectodermally derived squamous epithelia, including hair follicles, teeth, and oral and corneal epithelia. In addition, squamous metaplasia was observed in various epithelial-derived tissues, including the thymus. The aberrant growth of hair follicles and other appendages as well as the thymic abnormalities in K14-cre; ApcCKO/CKO mice suggest the Apc gene is crucial in embryonic cells to specify epithelial cell fates in organs that require epithelial–mesenchymal interactions for their development.

We evaluated the detailed expression patterns of Runx1 and Sox9 in various types of bone formation, and determined whether Runx1 expression was affected by Runx2 deficiency and Runx2 expression by Runx1 deficiency. Our results indicate that both Runx1 and Sox9 are intensely expressed in the future osteogenic cell compartment and in cartilage. The pattern of Runx1 and Sox9 expression suggests that both genes could potentially be involved in incipient intramembranous bone formation during craniofacial development.Introduction: Runx1, a gene essential for hematopoiesis, contains RUNX binding sites in its promoter region, suggesting possible cross-regulation with Runx2 and potential regulatory roles in bone development. On the other hand, Sox9 is essential for chondrogenesis, and haploinsufficiency of Sox9 leads to premature ossification of the skeletal system. In this study, we studied the possible roles of Runx1 and Sox9 in bone development. Materials and Methods: Runx1, Runx2/Osf2, and Sox9 expression was evaluated by in situ hybridization in the growing craniofacial bones of embryonic day (E)12-16 mice and in the endochondral bone-forming regions of embryonic and postnatal long bones. In addition, we evaluated Runx2/Osf2 expression in the growing face of Runx1 knockout mice at E12.5 and Runx1 expression in Runx2 knockout mice at E14.5. Results: Runx1 and Sox9 were expressed in cartilage, and the regions of expression expanded to the neighboring Runx2-expressing osteogenic regions. Expression of both Runx1 and Sox9 was markedly downregulated on ossification. Runx1 and Sox9 expression was absent in the regions of endochondral bone formation and in actively modeling or remodeling bone tissues in the long bones as well as in ossified craniofacial bones. Runx2 expression was not affected by gene disruption of Runx1, whereas the expression domains of Runx1 were extended in Runx2

Teeth form as ectodermal appendages, and their morphogenesis is regulated by conserved signaling pathways. The shape of the tooth crown results from growth and folding of inner dental epithelium, and the cusp patterning is regulated by transient signaling centers, the enamel knots. Several signal proteins in the transforming growth factor-␤ (TGF␤) superfamily are required for tooth development. Follistatin is an extracellular inhibitor of TGF␤ signaling. To investigate the roles of follistatin during tooth development, we analyzed in detail the expression patterns of follistatin, activin ␤A, as well as Bmp2, Bmp4, and Bmp7 during tooth morphogenesis. We also examined the tooth phenotypes of follistatin knockout mice and of transgenic mice overexpressing follistatin in the epithelium under the keratin 14 (K14) promoter. The folding of the dental epithelium was aberrant in the molars of follistatin knockout mice, and the cusps were shallow with reduced cell proliferation and lack of anteroposterior polarization. The functions of both primary and secondary enamel knots were apparently disturbed. In K14 -follistatin transgenic mice, the molar cusp pattern was also seriously affected (although different from the follistatin knockouts) and the occlusal surfaces of the molars were whorled. Their enamel was prematurely worn. In addition, all of the third molars were missing. Our results indicate that follistatin regulates morphogenesis and shaping of the tooth crown. We propose that finely tuned antagonistic effects between follistatin and TGF␤ superfamily signals are critical for enamel knot formation and function, as well as for patterning of tooth cusps. Developmental Dynamics 231:98 -108, 2004.

This paper puts forward an application of IOT technologies in campus security，such as the RFID, wireless sensor networks, Zigbee，and so on, and designs an integrative campus security system including RFID application system, network video monitoring system and fire alarm system, etc. It will contribute to build “safe campus” and “intelligent campus”, and resolve the serious situation facing the campus safety.

Electric vehicle (EV) is the greatest potential production of new energy vehicles. It plays a very important role in the area of energy conservation and reduction of pollutant emissions. In order to accelerate EV industrialization, the paper proposed a motor design method,which need to combine the automobile theory with the design permanent machine (PM). The paper considered the vehicle’s dynamic parameters, defined the motor’s basic parameters and designed the dimensions of electromagnetic structure, and then analyzed the field of the motor using finite element method (FEM). The paper firstly presents that drive motor’s design should consider two respects: one is the vehicle and another is the drive motor. In view of length of paper, only the no-load field analysis was proposed in this paper. The effectiveness of the proposed method is verified by the analysis results.

In order to obtain the low synchronous speed, fractional slot concentrated winding is adopted in generation system. This paper analyzed the pole/slot combination rule, and studied the electromagnetic design method. By the finite element software, the characteristics is analyzed for this fractional-slot concentrated-winding permanent magnet generator, the result shows that this generator has a good performance, thus yet proves that fractional slot concentrated winding scheme is feasible.

This paper puts forward the unique design, through the research by solar panels, battery, the converter and photovoltaic power generation system composed by switch electrical, and according to the characteristics of solar panels and batteries, the actual situation and the requirements of a stable system, the battery charging and discharging control, etc. Then this paper further researched control strategies of the two kinds of operating mode of electric power grid and battery from nets, designed a converter of rated power 50 kW used for light storage complementary power generation system and light storage complementary test platform. Using the test platform to do the storage battery charging and discharging experiments and away from the grid experiments, the final experiment results show that the hardware design and the control strategy in this paper are proposed correctness and effectiveness.