A Methodological Approach for Motor Selection in Dental Impression Material Dispensers Using Experimental and Image Analysis Techniques.

This study presents a methodology to prevent the overdesign of electric dispensers for dental impression materials by analyzing the necessary load and determining the appropriate pressurization speed and drive motor capacity. We derived an equation to calculate the required torque and rotational speed of the motor based on the extrusion load and the speed of the impression material. A specialized load measurement system was developed to measure the load necessary to extrude the impression material. Through experiments and image processing, we measured the radius of curvature of the trajectory of the impression material and correlated it with the pressurization speed. Techniques such as position coordinate plotting, curve fitting, and circle fitting were employed to determine the pressurization speed that aligns with the manufacturer's recommended curvature radius. These findings led to a substantial decrease in the necessary motor torque and rotational speed compared with the current standards. This research provides a systematic approach to sizing drive motors using extrusion load and pressurization speed, aiming to reduce overdesign, power consumption, and the weight and size of the motor and battery, thereby contributing to the development of more efficient and compact dental impression material dispensers.

Heat shock protein 60 couples an oxidative stress-responsive p38/MK2 signaling and NF-κB survival machinery in cancer cells.

Mitochondria communicate with other cellular compartments via the secretion of protein factors. Here, we report an unexpected messenger role for heat shock protein 60 (HSP60) as a mitochondrial-releasing protein factor that couples stress-sensing signaling and cell survival machineries. We show that mild oxidative stress predominantly activates the p38/MK2 complex, which phosphorylates mitochondrial fission factor 1 (MFF1) at the S155 site. Such phosphorylated MFF1 leads to the oligomerization of voltage anion-selective channel 1, thereby triggering the formation of a mitochondrial membrane pore through which the matrix protein HSP60 passes. The liberated HSP60 associates with and activates the IκB kinase (IKK) complex in the cytosol, which consequently induces the NF-κB-dependent expression of survival genes in nucleus. Indeed, inhibition of the HSP60 release or HSP60-IKK interaction sensitizes the cancer cells to mild oxidative stress and regresses the tumorigenic growth of cancer cells in the mouse xenograft model. Thus, this study reveals a novel mitonuclear survival axis responding to oxidative stress.

Oral health behaviours according to demographic characteristics in Korean adolescents: a national representative sample.

OBJECTIVES: To provide information on how to teach correct oral health behaviour to youths and to develop programmes to that end, this study examined the oral health behaviour and demographic characteristics of adolescents. METHODS: The raw data of 'The Third 2007 Youth Health Behavior Online Survey' carried out by the Korea Center for Disease Control and Prevention were analysed. Independent t-test, one-way ANOVA, and chi-squared analyses were used to assess the relationships between oral health behaviours and demographic characteristics. RESULTS: The oral health behaviour of the adolescents who were investigated differed significantly depending on their demographic characteristics (P<0.001). Tooth brushing frequency differed significantly depending on gender and student grade (P<0.001) and the frequency of visits to a dental clinic differed depending on the gender, student grade, type of residential area (urban/rural), and type of school (middle or high) (P<0.001). School grade, type of residential area, and type of school also affected the likelihood of receiving preventive dental treatment (P<0.001). CONCLUSIONS: Adolescents who were in lower grades, female, and lived in large urban communities visited dental clinics more frequently and received more preventive dental treatment than adolescents who were in higher grades, male and resided in small urban and rural areas. These results highlight the need for the further development and dissemination of oral health programmes.