<strong>Background and Objective:</strong> The aesthetic products’ safety should not be neglected to the detriment of the market. This study aimed to evaluate the mutagenic potential of commercial inks. I...<strong>Background and Objective:</strong> The aesthetic products’ safety should not be neglected to the detriment of the market. This study aimed to evaluate the mutagenic potential of commercial inks. It was formulated with organic (P1) and inorganic (P2) pigments for eyebrows microblading using a validated method by regulatory agencies, the <em>Salmonella</em>/microsome assay, to assure the safety of use. <strong>Methods:</strong> The assay was carried out in three steps: preliminary toxicity, medium without (-S9), and presence (+S9) of metabolic activation. The strains, auxotrophic to histidine (His-) TA97a, TA98, TA100, and TA102, were exposed to both types of inks, in triplicate, compared to negative and positive controls. Data were statistically analyzed, and values with mutagenic index ≥ 2.0 were indicative of mutagenicity. <strong>Results:</strong> The inks with organic (P1) and inorganic (P2) pigments were not toxic to TA98 and TA100 S. <em>typhimurium</em> tester strains, even at concentrations applied in humans. Both inks were not mutagenic either in the absence or presence of metabolic activation in the tested concentrations, including that applied in humans. The assay showed that P1 and P2 were not direct (-S9) or indirect (+S9) mutagens as commercially formulated. <strong>Conclusions:</strong> These results indicate that applying these inks on organisms with microsomal enzymes, including humans, is safe since no compound in the inks became more toxic to induce the bacterial reverse mutation.展开更多
The timing and mechanisms of the human occupation of the demanding high-altitude Tibetan Plateau environment are of great interest.Here,we report on our reinvestigations and dating of the Nwya Devu site,located nearly...The timing and mechanisms of the human occupation of the demanding high-altitude Tibetan Plateau environment are of great interest.Here,we report on our reinvestigations and dating of the Nwya Devu site,located nearly 4600 meters above sea level on the central Tibetan Plateau.A new microblade techno-complex was identified on a lower lake shore at this site,distinct from the previously reported blade tool assemblage.These two lithic assemblages were dated to 45.6±2.6 and10.3±0.5 ka using optically stimulated luminescence and accelerator mass spectrometry^(14)C methods.They represent,respectively,the earliest known Paleolithic and microlithic sites on the interior Tibetan Plateau,indicating multiple occupation episodes of hunter-gatherers during the past 45 ka.Our studies reveal that relatively stable depositional conditions and a paleoenvironment characterized by a comparatively warm climate facilitated these multiple occupations at Nwya Devu.The contemporaneous occurrence of the Upper Paleolithic blade technology on the Tibetan Plateau and most of Eurasia between 50 and 40 ka indicates rapid,large-scale dispersals of humans that profoundly affected human demography on a large scale.Combining new archaeological evidence and previously reported genetic data,we conclude that the Tibetan Plateau provided a relatively stable habitat for Upper Paleolithic hunter-gatherers,which may have contributed to the complex and multiple-origin gene pool of present-day Tibetans.展开更多
Microblade assemblages are among the most common prehistoric archaeological materials found on the Tibetan Plateau(TP)and are thought to indicate large scale migration to and settlement of the TP.Few microblade sites,...Microblade assemblages are among the most common prehistoric archaeological materials found on the Tibetan Plateau(TP)and are thought to indicate large scale migration to and settlement of the TP.Few microblade sites,however,have been systematically excavated,especially in the remotest,highest-elevation regions of the TP.The timing of the large-scale arrival,spread,and permanent settlement of people on the TP therefore remains controversial.In this paper,we report on a recently excavated site,Locality 3 of the Nwya Devu Site(ND3),located at 4600 meters above sea level(masl),near the shore of Ngoin Lake,on the interior TP.Our analyses reveal a fairly typical microblade technological orientation and two types of microblade cores:wedge-shaped and semi-conical,which are similar to those found throughout North China.Using Optically Stimulated Luminescence(OSL)dating and AMS^(14)C dating,the age of ND3 ranges from 11 to 10 ka.This date range indicates ND3 is the oldest microblade site yet recorded in the remote,high-elevation regions of the TP and thus provides important information about when and how hunter-gatherers using microblades began exploiting the higher altitudes of the TP.Taken together,studies at ND3 and throughout the TP suggest that a microblade adaptation is associated with the first prolonged human occupation of the plateau and that microblades played a significant role in mediating the risks and facilitating the mobility necessary to permanently inhabit the TP.展开更多
文摘<strong>Background and Objective:</strong> The aesthetic products’ safety should not be neglected to the detriment of the market. This study aimed to evaluate the mutagenic potential of commercial inks. It was formulated with organic (P1) and inorganic (P2) pigments for eyebrows microblading using a validated method by regulatory agencies, the <em>Salmonella</em>/microsome assay, to assure the safety of use. <strong>Methods:</strong> The assay was carried out in three steps: preliminary toxicity, medium without (-S9), and presence (+S9) of metabolic activation. The strains, auxotrophic to histidine (His-) TA97a, TA98, TA100, and TA102, were exposed to both types of inks, in triplicate, compared to negative and positive controls. Data were statistically analyzed, and values with mutagenic index ≥ 2.0 were indicative of mutagenicity. <strong>Results:</strong> The inks with organic (P1) and inorganic (P2) pigments were not toxic to TA98 and TA100 S. <em>typhimurium</em> tester strains, even at concentrations applied in humans. Both inks were not mutagenic either in the absence or presence of metabolic activation in the tested concentrations, including that applied in humans. The assay showed that P1 and P2 were not direct (-S9) or indirect (+S9) mutagens as commercially formulated. <strong>Conclusions:</strong> These results indicate that applying these inks on organisms with microsomal enzymes, including humans, is safe since no compound in the inks became more toxic to induce the bacterial reverse mutation.
基金supported by the National Natural Science Foundation of China(Grant Nos.41888101,41977380 and 42072033)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDB26000000 and XDA2004010102)+3 种基金the Second Tibetan Plateau Scientific Expedition and Research(Grant No.2019QZKK0601)the National Social Science Foundation of China(Grant No.21@WTK001)supported by the Chinese Academy of Sciences President’s International Fellowship Initiative Award(Grant No.2018VCA0016)the Je Tsongkhapa Endowment for Central and Inner Asian Archaeology at the University of Arizona。
文摘The timing and mechanisms of the human occupation of the demanding high-altitude Tibetan Plateau environment are of great interest.Here,we report on our reinvestigations and dating of the Nwya Devu site,located nearly 4600 meters above sea level on the central Tibetan Plateau.A new microblade techno-complex was identified on a lower lake shore at this site,distinct from the previously reported blade tool assemblage.These two lithic assemblages were dated to 45.6±2.6 and10.3±0.5 ka using optically stimulated luminescence and accelerator mass spectrometry^(14)C methods.They represent,respectively,the earliest known Paleolithic and microlithic sites on the interior Tibetan Plateau,indicating multiple occupation episodes of hunter-gatherers during the past 45 ka.Our studies reveal that relatively stable depositional conditions and a paleoenvironment characterized by a comparatively warm climate facilitated these multiple occupations at Nwya Devu.The contemporaneous occurrence of the Upper Paleolithic blade technology on the Tibetan Plateau and most of Eurasia between 50 and 40 ka indicates rapid,large-scale dispersals of humans that profoundly affected human demography on a large scale.Combining new archaeological evidence and previously reported genetic data,we conclude that the Tibetan Plateau provided a relatively stable habitat for Upper Paleolithic hunter-gatherers,which may have contributed to the complex and multiple-origin gene pool of present-day Tibetans.
基金supported by the National Key Research and Development Project of China(Grant No.2021YFC1523603)the Second Tibetan Plateau Scientific Expedition and Research(Grant No.2019QZKK0601)+1 种基金the National Natural Science Foundation of China(Grant Nos.42072033&41977380)the National Social Science Foundation of China(Grant Nos.23&ZD268&21@WTK001)。
文摘Microblade assemblages are among the most common prehistoric archaeological materials found on the Tibetan Plateau(TP)and are thought to indicate large scale migration to and settlement of the TP.Few microblade sites,however,have been systematically excavated,especially in the remotest,highest-elevation regions of the TP.The timing of the large-scale arrival,spread,and permanent settlement of people on the TP therefore remains controversial.In this paper,we report on a recently excavated site,Locality 3 of the Nwya Devu Site(ND3),located at 4600 meters above sea level(masl),near the shore of Ngoin Lake,on the interior TP.Our analyses reveal a fairly typical microblade technological orientation and two types of microblade cores:wedge-shaped and semi-conical,which are similar to those found throughout North China.Using Optically Stimulated Luminescence(OSL)dating and AMS^(14)C dating,the age of ND3 ranges from 11 to 10 ka.This date range indicates ND3 is the oldest microblade site yet recorded in the remote,high-elevation regions of the TP and thus provides important information about when and how hunter-gatherers using microblades began exploiting the higher altitudes of the TP.Taken together,studies at ND3 and throughout the TP suggest that a microblade adaptation is associated with the first prolonged human occupation of the plateau and that microblades played a significant role in mediating the risks and facilitating the mobility necessary to permanently inhabit the TP.
