ABSTRACT
Background: Oral infections have been seen in humans since ancient times. Excessive penetration of this infection can cause human death. Most of these infections are gum cysts and abscesses. The cyst creates large hard lumps in the gums, which is causes loose, and protruding teeth and abscesses, causing cavities in the jawbone and teeth. In this article, we have discussed for this infectious disease in 4000 - year - old ancient humans from Qazvin Province, Iran. The bone remains of our research are related to Sagezabad ancient cemetery in Qazvin plain. Methods: We tried to use reliable international atlases to get detailed information about ancient oral infections. The bones were extracted from the 2019 excavation of the Ghara Tappe area of Sagezabad for the Iron Age 2nd and 3rd Qazvin plains of Iran. This cemetery belongs to the period of the Medes Kingdom (pre - Achaemenian kingdom) in Iran. Results: We have discussed one of the ancient cemeteries with a large number of ancient populations. In this cemetery, there are signs of war and infectious diseases on the bones, which can be clearly seen. We have specially mentioned the abscess as the cause of oral infection from Sagezabad cemetery. Conclusion: Oral infection existed in Iran since 2000 BC. Of course, this infection was common in ancient times and even Paleolithic period, like Homo Heidelbergensis.
ABSTRACT
In this paper, we report on the preparation of S, N co-doped carbon quantum dots (CQDs)/TiO2 nanocomposite using a hydrothermal process where S, N-CQDs were concurrently synthesized and anchored to the surface of the TiO2. The prepared nanocomposite was carefully characterized to identify the morphology and structure, crystallinity, chemical composition and optical properties. The photocatalytic activity of the nanocomposite was investigated for degradation of acid red 88 (AR88) under visible light irradiation. The capability of the S, N-CQDs/TiO2 nanocomposite to remove AR88 (77.29%) was higher than that of pure TiO2 (23.7%). In order to determine the influencing factors on the photocatalytic activity of the prepared nanocomposite, we studied various contents of the photocatalyst, the effect of pH and the content of H2O2. Further investigations were conducted to reveal the mechanism of photocatalytic degradation using radical scavenging agents. The stability and reusability of the S, N-CQDs/TiO2 photocatalyst was tested in four reaction cycles (870 min) which showed a 25% loss of photoactivity after the fourth photocatalytic reaction.
