Search Results (3)

Around the world, a large number of stone artifacts have been exposed to air for long periods of time, showing multiple types of deterioration that have attracted widespread attention. Among them, there is an often overlooked deterioration of stone artifacts, i.e., black stains on the surface of the calcareous stone, which are tightly bonded to the substrate as a result of the long-term deposition of air pollution. However, due to the current lack of a clear understanding of the black stains, people often tend to use the wrong cleaning and conservation methods, which is not conducive to sustainable conservation. Therefore, there is an urgent need to comprehensively recognize the black stains in terms of material properties and environmental sustainability to guide scientific sustainable conservation methods. To this end, in this paper, we take the black stains observed on marble buildings in the Xianling Tomb, China, as an example, and for the first time, we aim to create a comprehensive understanding of black deposition from the aspects of material properties and environmental characteristics. Multi-analytical approaches, including polarized light microscopy, X-ray fluorescence (XRF), and scanning electron microscopy with energy dispersive X-ray spectrometry (SEM-EDS), were employed to discern the differences between the substrate and black stains. The results revealed that the formation of black stains was attributed to prolonged exposure to various air pollutants (PM, SO₂, NO₂, CO, and O₃). Subsequently, observational data from 2015 to 2023 were utilized to investigate the temporal evolution of local air pollutants and their coupled resonances. Multi-scale variations (annual, seasonal, monthly, weekly, and daily) of pollutant concentration sequences were identified, which helps us to have a clearer perception and to proactively control air pollutants in the region from different cycles. In addition, wavelet coherence (WTC) demonstrated significant time-scale dependency in correlation with air pollutants, which provides effective data support for the coordinated control of air pollutants. This study reveals the mechanism of black stain deterioration on stone artifact surfaces, provides data support for the control and prediction of air pollutants oriented to the sustainable conservation of stone artifacts, and provides a novel and comprehensive approach to the scientific knowledge and sustainable conservation of stone artifacts. Full article

We report a case of a patient with Dubin–Johnson syndrome confirmed by a genetic study. A 50-year-old woman who had symptoms of intermittent right upper quadrant abdominal pain was diagnosed with calculous cholecystitis at another institute and was presented to our hospital for a cholecystectomy. She had no history of liver disease, and her physical examination was normal. Abdominal computed tomography showed a gallbladder stone with chronic cholecystitis. During a laparoscopic cholecystectomy for cholecystitis, a smooth, black-colored liver was noted, and a liver biopsy was performed. The biopsy specimen showed coarse, dark brown granules in centrilobular hepatocytes via hematoxylin and eosin staining. We performed a genetic study using the blood samples of the patient. In the adenosine triphosphate-binding cassette subfamily C member 2 (ABCC2) mutation study, a missense mutation in exon 18 was noted. Based on the black-colored liver without nodularity, conjugated hyperbilirubinemia, the liver biopsy results of the coarse pigment in centrilobular hepatocytes, and the ABCC2 mutation, Dubin–Johnson syndrome was diagnosed. The patient was managed with conservative care using hepatotonics. One month after follow-up, total bilirubin and direct bilirubin remained in a similar range. Another follow-up was planned a month later, and the patient maintained her use of hepatotonics. Full article

White building components, whether decorative or the overall structure, are susceptible to extreme weathering conditions, which affect the durability of the building’s external surface. In particular, white natural stone materials can provide buildings with beauty, durability, and sustainability, but this beauty is affected by key factors determining their weather resistance, namely physical properties such as porosity and acid and alkali resistances. As indicated by a past study, marble used as the exterior wall of a building in a similar environment will exhibit tarnishing after six months of weathering. Taiwan is a subtropical island, so the weather resistance of building materials to this environment is worthy of attention. As pointed out by the study, raw stone materials containing zirconium and silica can have greater weather resistance, do not easily change color, and possess good stress resistance properties. Focusing on this, this study attempted to identify stone materials with such compositions and sent samples to SGS (Societe Generale de Surveillance S.A., New Taipei City, Taiwan) for testing of weather resistance. This paper uses Spanish artificial stones for the study and observes the changes in the surface cleanliness on two buildings in Yilan County and Taipei in Taiwan after exposure to sun and rain. The experiments were conducted over two years. The study results showed that the artificial stones displayed no change in outward appearance under both rainy and acid rain environments. In Yilan, construction of an exterior wall was carried out in February 2018. The exterior wall used the white artificial stone directly from the manufacturer, and the black artificial stone with added paint for stone protection. After two months, the black artificial stone covered with paint exhibited a change in color and stains appeared on the surface, while the white artificial stone not covered with paint maintained the same cleanliness after two years. In Taipei, white Spanish artificial stone was used for the exterior wall of an entire building block in February 2020. After the frame was dismantled in September 2020, the color was found to be unaffected, being as pure white as it was when new. Therefore, this study selected Spanish artificial stone for the design of a building’s exterior wall, as the cleanliness of the stone surface is not affected and it has good applicability in rainy and acid rain island environments. Full article