Colorectal cancer(CRC)is one of the most common malignant life-threatening tumors,with serious impacts on patient quality of life.Src homology 2 domain-containing protein tyrosine phosphatase(SHP2)has recently become a hot topic in the field of cancer research,and has demonstrated a close relationship with CRC.SHP2,encoded by the PTPN11 gene,is a non-receptor tyrosine kinase commonly present in various tissues and cells of the human body.Existing research shows that SHP2 plays a crucial role in regulating CRC and colitis-associated colon cancer(CAC),and the emergence of SHP2 allosteric inhibitors has identified SHP2 as a potential new therapeutic target for patients with CRC.Here we review the structure of SHP2 and its roles in CRC and CAC.

Colorectal cancer(CRC)is one of the most common malignant life-threatening tumors,with serious impacts on patient quality of life.Src homology 2 domain-containing protein tyrosine phosphatase(SHP2)has recently become a hot topic in the field of cancer research,and has demonstrated a close relationship with CRC.SHP2,encoded by the PTPN11 gene,is a non-receptor tyrosine kinase commonly present in various tissues and cells of the human body.Existing research shows that SHP2 plays a crucial role in regulating CRC and colitis-associated colon cancer(CAC),and the emergence of SHP2 allosteric inhibitors has identified SHP2 as a potential new therapeutic target for patients with CRC.Here we review the structure of SHP2 and its roles in CRC and CAC.

Objective To compare the impact of NaClO and EDTA pretreatment on the enamel surfaces pore exposure rate,resin in-filtration effectiveness and shear bond strength between the enamel white spot lesions(WSLs)and resin composite.Methods A total of 104 sound premolars were selected for the study.4 mm×4 mm×2 mm enamel blocks from 64 sound premolars were cut in the center of the buccal surfaces of the teeth.All blocks were randomly divided into five groups:group SE(sound enamels as negative control);group DE(enamel blocks demineralised as positive control);group RI(resin infiltration);group N/RI(5.25％NaClO pretreatment and resin infiltration)and group E/RI(17％EDTA pretreatment and resin infiltration).The pore exposure rate of enamel surfaces and resin penetration depths were observed by scanning electron microscopy(SEM)and confocallaser scanning microscopy(CLSM)in each group.The remaining 40 premolars were cut from the cervical roots and the residual crowns were embedded in self-condensing resin ma-terial(buccal surfaces of the enamel exposed only).According to the grouping information,the samples were given the corresponding pretreatments and resin infiltration respectively and were bonded with a cylindrical resin cylinder on the buccal enamel surface for shear bond test.The shear bond strength and fracture modes were recorded and analyzed in each group.Results Compared to group RI,the pore exposure rate of the enamel surface,resin penetration depths,and percentage of resin penetration area in the N/RI and E/RI groups were significantly increased(P＜0.05).The shear bond strength of the samples in group SE was the highest,and the lowest in group DE.Compared to group DE,the shear bond strength in groups RI,N/RI,and E/RI was significantly increased(P＜0.05).Con-clusion Enamel surface pretreatment with 5.25％NaClO or 17％EDTA has been demonstrated to effectively enhance the enamel pore exposure rate,resin penetration depth and the shear bond strength between WSLs and resin composite.

Objective To compare the impact of NaClO and EDTA pretreatment on the enamel surfaces pore exposure rate,resin in-filtration effectiveness and shear bond strength between the enamel white spot lesions(WSLs)and resin composite.Methods A total of 104 sound premolars were selected for the study.4 mm×4 mm×2 mm enamel blocks from 64 sound premolars were cut in the center of the buccal surfaces of the teeth.All blocks were randomly divided into five groups:group SE(sound enamels as negative control);group DE(enamel blocks demineralised as positive control);group RI(resin infiltration);group N/RI(5.25％NaClO pretreatment and resin infiltration)and group E/RI(17％EDTA pretreatment and resin infiltration).The pore exposure rate of enamel surfaces and resin penetration depths were observed by scanning electron microscopy(SEM)and confocallaser scanning microscopy(CLSM)in each group.The remaining 40 premolars were cut from the cervical roots and the residual crowns were embedded in self-condensing resin ma-terial(buccal surfaces of the enamel exposed only).According to the grouping information,the samples were given the corresponding pretreatments and resin infiltration respectively and were bonded with a cylindrical resin cylinder on the buccal enamel surface for shear bond test.The shear bond strength and fracture modes were recorded and analyzed in each group.Results Compared to group RI,the pore exposure rate of the enamel surface,resin penetration depths,and percentage of resin penetration area in the N/RI and E/RI groups were significantly increased(P＜0.05).The shear bond strength of the samples in group SE was the highest,and the lowest in group DE.Compared to group DE,the shear bond strength in groups RI,N/RI,and E/RI was significantly increased(P＜0.05).Con-clusion Enamel surface pretreatment with 5.25％NaClO or 17％EDTA has been demonstrated to effectively enhance the enamel pore exposure rate,resin penetration depth and the shear bond strength between WSLs and resin composite.

Objective: To investigate the efficacy of different bleaching methods on white-spot lesions of the enamel using optical coherence tomography and to evaluate its feasibility for monitoring the therapeutic effects on white-spot lesions. Methods: Forty-eight sound premolars extracted for orthodontic reasons were selected and cut for 4 mm×4 mm×2 mm enamel blocks in buccal surfaces of the crowns. The samples were covered with acid-resistant varnish (except for the buccal surfaces) and immersed in demineralization solution for 18 days to establish the white-spot lesion models of the enamels. Samples were randomly divided into four groups (n=12). Group A was given demineralization only. Specimens in Group B, C and D were treated with 40% hydrogen peroxide, resin infiltration and 40% hydrogen peroxide combined with resin infiltration, respectively. Eight samples in each group were randomly selected. OCT was applied to observe the optical changes of the enamel surface and according to the OCT scanning results, the demineralization depth of enamel samples in each group was calculated. Then, the enamel blocks were embedded in epoxy resins, except the buccal surfaces, and measured for the microhardness values of the enamel surface by a microindentation hardness tester. Four samples in each group were cut longitudinally, and the ultrastructural changes of enamel samples in each group were observed by scanning electron microscope. Results: OCT showed that the light scattering characteristics of enamel surface changed in all groups, and the bright layer was formed, but the thickness of bright layer in Group C and D was significantly lower than that in Group A and B (P<0.05). The microhardness values (kg/mm2) of the samples in Group A-D were (214.99±31.70), (250.66±33.64), (312.42±18.01) and(286.53±26.65), respectively. The microhardness of enamel surfaces in Group C and D was significantly higher than that in Group A and B (P<0.05), and the ultrastructure of enamel surfaces in Group C and D were more flat and dense in SEM observation (P<0.05). Conclusion The methods of resin infiltration therapy or 40% hydrogen peroxide combined with resin infiltration could effectively improve white-spot lesions of the enamel and the non-invasive OCT can be used as a better evaluation method for the diagnosis and treatment of white-spot lesions of the enamel.

Objective:To analyze the current situation of the course of Pharmaceutical Analysis in the education and training of undergraduate students, explore the teaching reform and innovation to better accommodate the pharmacy education in the new era and build an advanced mode for training pharmaceutical talents with interdisciplinary expertise that meet the requirements and needs of job market. Methods:The first stage was to investigate the suggestions and needs of teaching reform; the second stage was to carry out the exploration and practice of the course reform; the third stage was to evaluate the teaching effect.Results:The demand survey showed that the teaching content, course design, and teaching methods of the Pharmaceutical Analysis need to be further optimized and expanded. Conclusion:By adjusting the teaching content, expanding teaching methods, innovating diversified teaching practices, and integrating the "curriculum ideology and politics" into the construction, the course reform has stimulated students' interest in learning and innovative spirit, strengthened their theoretical literacy and practical ability, and cultivated their international vision and lofty professional ethics.

OBJECTIVETo evaluate the effect of different subgingival root exposure methods, namely, crown lengthening or forced eruption, and different ferrule lengths on fracture resistance of a residual root restored with a carbon fiber post-and-core system.

METHODSFifty-six extracted endodontically-treated mandibular first premolars were sectioned 1.0 mm coronal to the buccal cementoenamel junction. All the models were divided randomly into seven groups that each consist of eight roots. Group A was given non-ferrule as control. Simulated crown lengthening was performed for the dentin ferrule design in the cervical tooth structure for Groups B, C, and D with a ferrule length of 1.0, 2.0, and 3.0 mm, respectively. Simulated forced eruption was performed with a ferrule length of 1.0, 2.0, and 3.0 mm in the cervical tooth structure for Groups E, F, and G, respectively. After restoration with prefabricated carbon fiber post-and-core system, each specimen was embedded in a self-cured acrylic resin block from 2.0 mm apical to the margins of a cast Ni-Cr alloy crown, then loaded at 150 degrees from the long axis in a universal testing machine at a crosshead speed of 1.0 mm min(-1) until fracture. Data of failure loads and fracture mode were recorded and analyzed.

RESULTSMean failure loads for Groups A to G were (1.13 +/- 0.15), (1.27 +/- 0.18), (1.02 +/- 0.11), (1.05 +/- 0.12), (1.63 +/- 0.14), (1.92 +/- 0.19), and (1.93 +/- 0.15) kN, respectively. The effects of root exposure method and ferrule design differed significantly, and two factors exhibited significant interaction (F=33.396, P<0.0001). When the ferrule lengths were the same, fracture loads in the simulated forced eruption groups were significantly higher than those of the simulated crown lengthening groups (P<0.001). No statistical differences in fracture mode were observed among all groups (P=1.00).

CONCLUSIONMore than 1.0 mm ferrule placement on the apical crown margin by using forced eruption significantly increases fracture resistance.

Bicuspid ; Crowns ; Dental Stress Analysis ; Humans ; In Vitro Techniques ; Post and Core Technique ; Tooth Fractures ; Tooth Root

Objective To evaluate the effect of different subgingival root exposure methods, namely, crown lengthening or forced eruption, and different ferrule lengths on fracture resistance of a residual root restored with a carbon fiber post-and-core system. Methods Fifty-six extracted endodontically-treated mandibular first premolars were sectioned 1.0 mm coronal to the buccal cementoenamel junction. All the models were divided randomly into seven groups that each consist of eight roots. Group A was given non-ferrule as control. Simulated crown lengthening was performed for the dentin ferrule design in the cervical tooth structure for Groups B, C, and D with a ferrule length of 1.0, 2.0, and 3.0 mm, respectively. Simulated forced eruption was performed with a ferrule length of 1.0, 2.0, and 3.0 mm in the cervical tooth structure for Groups E, F, and G, respectively. After restoration with prefabricated carbon fiber post-and-core system, each specimen was embedded in a self-cured acrylic resin block from 2.0 mm apical to the margins of a cast Ni-Cr alloy crown, then loaded at 150° from the long axis in a universal testing machine at a crosshead speed of 1.0 mm·min-1 until fracture. Data of failure loads and fracture mode were recorded and analyzed. Results Mean failure loads for Groups A to G were (1.13±0.15), (1.27±0.18), (1.02±0.11), (1.05±0.12), (1.63±0.14), (1.92±0.19), and (1.93±0.15) kN, respectively. The effects of root exposure method and ferrule design differed significantly, and two factors exhibited significant interaction (F=33.396,P<0.0001). When the ferrule lengths were the same, fracture loads in the simulated forced erup-tion groups were significantly higher than those of the simu-lated crown lengthening groups (P<0.001). No statistical differences in fracture mode were observed among all groups (P=1.00). Conclusion More than 1.0 mm ferrule placement on the apical crown margin by using forced eruption signifi-cantly increases fracture resistance.