Search

Copyright of African Journal of Reproductive Health is the property of Women's Health & Action Research Centre and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, we established an experimental rat model to simulate orthodontic tooth movement relapse and a human periodontal ligament stem cell (PDLScs) model. Our aim was to explore the relationship between microRNA-146a (miR-146a) expression in periodontal tissue, the inflammatory factor interleukin-6 (IL-6), and orthodontic relapse subsequent to mechanical intervention. In the animal experiment, a total of 30 healthy male Wistar rats were randomly allocated to either the control group (n=6) or the model group (n=24). In the model group, the orthodontic appliance was removed 14 days after force application. Gingival crevicular fluid (GcF) and periodontal tissue samples were collected at intervals of days 0, 7, 14, and 21 following removal of the orthodontic appliance to assess alterations in miR-146a and IL-6 expressions. In the in vitro cell culture study, human premolar tooth tissue was isolated 24 hours following the addition of the transfection reagent to harvest PDLScs. Reverse transcription quantitative polymerase chain reaction was employed to evaluate the expression levels of the miRNA-146a gene, while Western blot analysis was utilized to assess the production of the IL-6 protein. As a result in comparison to the control group, the protein expression of IL-6 notably escalated to its peak value in the model-day 7 group (p<0.05). Subsequently, although experiencing a slight decline, the IL-6 expression in the modelday 14 group remained significantly elevated compared to control group (p<0.05). In the model-day 21 group, the protein expression of IL-6 approached that of the control group, with no significant difference observed (p>0.05). conversely, in relation to the control group, the gene expression of miR-146a drastically decreased to its lowest point in the model-day 7 group (p<0.05). While exhibiting a slight increase, the miR-146a expression in the model-day 14 group remained significantly diminished compared to control group (p<0.05). Following the identification of human periodontal ligament cells (hPDLcs) through immunofluorescence in the in vitro study, a subsequent experiment was conducted to specifically inhibit miR-146a expression. In comparison to the control group, the protein expression of IL-6 demonstrated a significant increase in the anti-miRNA oligodeoxyribonucleotide (AMO) group, where miR-146a expression was effectively suppressed (p<0.05). Throughout the process of orthodontic tooth movement relapse in rats, there was a notable reduction in the gene expression of miR-146a, accompanied by a significant increase in the expression of IL-6. [ABSTRACT FROM AUTHOR]

The NiCr/YSZ coating was fabricated on γ-TiAl alloy by double glow plasma surface metallurgy technology and multi-arc ion plating technology. The microstructure, microhardness, bonding strength, and burn resistance of NiCr/YSZ coating were studied in detail. The results showed that the NiCr/YSZ coating was dense and homogeneous, including a duplex structure of top YSZ ceramic coating and underlying Ni-Cr bond coating. The average microhardness of NiCr/YSZ coating was raised by a factor of about 2 compared to the γ-TiAl substrate. The thermal shock test indicated that the composite structure had superior bonding strength and the defects such as metal droplets on the ceramic coating were the source of cracks. The high-energy laser beam destroyed the surface of γ-TiAl alloy, forming protruding combustion products in ablation zone and splashing residues around ablation zone. When coated by NiCr/YSZ coating, the combustion process was delayed through isolating and dissipating heat. The ablation range was controlled and the ablation damage was reduced at the same irradiation power. The NiCr/YSZ coating preliminarily realized to improve the burn resistance of γ- TiAl alloy.

To improve the wear resistance of γ-TiAl alloy, Ta alloy layer was prepared on surface by double glow plasma surface alloying technique. The tribology behavior of Ta alloy layer against Si3N4 at 25℃, 350℃ and 500℃ were comparatively studied. The results showed that Ta alloy layer comprised a deposition layer and a diffusion layer. The deposition layer played a role in protection as a soft film. With the increase of temperature, the wear mechanism of γ-TiAl changed from abrasive wear to coexistence of abrasive wear and oxidation wear. Ta alloy layer’s wear mechanism changed from adhesive wear to coexistence of adhesive wear and oxidation wear. Surface Ta alloying process significantly reduced the wear volume, the specific wear rate and the friction coefficient of γ-TiAl and improved the wear resistance properties of γ-TiAl.

In the present paper, plasma surface alloying was implemented on powder metallurgy gears to improve its wear resistance based on double glow plasma surface metallurgy technology. A W-Mo alloy coating was obtained in the process. The morphology, microstructure and phase composition were investigated by SEM, EDS and XRD. The hardness was examined by Vickers hardness test and nanoindentation test. The tribological behavior of powder metallurgy gears before and after plasma surface alloying was evaluated on a ball-on-disc reciprocating sliding tribometer under dry sliding condition at room temperature. The results indicate that the W-Mo alloy coating is homogeneous without defects, which includes deposition layer and interdiffusion layer. The average microhardness of powder metallurgy gears before and after plasma surface alloying is 145.8 HV0.1 and 344.4 HV0.1, respectively; Nano hardness of deposition layer and interdiffusion layer is 5.76 GPa, 14.35 GPa, respectively. The specific wear rate of W-Mo alloy coating is lower than original PM gears. The wear mechanism of W-Mo alloy coating is slight adhesive wear. The W-Mo alloy coating prepared by double glow plasma surface alloying technology can effectively improve wear resistance of powder metallurgy gears.

OBJECTIVE: With the progress of technology, a variety of video shooting equipment appeared in people's vision. The improvement of video shooting performance and the decrease in production cost have not only lowered the production threshold, but also greatly facilitated people's daily life. Especially in the field of medical health monitoring, video shooting plays an increasingly important role. This paper summarizes the application of intelligent filming equipment in medical health monitoring under this background. MATERIALS AND METHODS: The intelligent filming equipment used in medical health monitoring is mainly applicable to patients who do not find it convenient to use contact shooting equipment, as well as patients with cardiovascular diseases and health detection and rehabilitation guidance for human knee joints. In this context, this paper uses literature survey methods and interdisciplinary research methods. RESULTS: We conclude that the measurement results of health monitoring devices obtained by using intelligent filming devices can only be used as a reference for medical personnel in further diagnosis, failing to reach the accuracy of direct medical diagnosis. CONCLUSIONS: The research of intelligent filming equipment in the field of medical health monitoring still needs continuous improvement. The monitoring results should be more stable and eventually industrialized, to solve the current problems in medical health monitoring. This will ultimately help to protect people's health. [ABSTRACT FROM AUTHOR]

A research indicates that high-voltage pulsed electric fields (PEF) are emerging in non-thermal food preservation technology. The pros and cons of the inactivation effect of PEF are evaluated.