Almost all hospitals are equipped with air-conditioning systems to provide a comfortable environment for patients and staff. However, the accumulation of dust and moisture within these systems increases the risk of transmission of microbes and have on occasion been associated with outbreaks of infection. Nevertheless, the impact of air-conditioning on the transmission of microorganisms leading to infection remains largely uncertain. We conducted a scoping review to screen systematically the evidence for such an association in the face of the coronavirus disease 2019 epidemic. PubMed, Embase and Web of Science databases were explored for relevant studies addressing microbial contamination of the air, their transmission and association with infectious diseases. The review process yielded 21 publications, 17 of which were cross-sectional studies, three were cohort studies and one case−control study. Our analysis showed that, compared with naturally ventilated areas, microbial loads were significantly lower in air-conditioned areas, but the incidence of infections increased if not properly managed. The use of high-efficiency particulate air (HEPA) filtration not only decreased transmission of airborne bioaerosols and various microorganisms, but also reduced the risk of infections. By contrast, contaminated air-conditioning systems in hospital rooms were associated with a higher risk of patient infection. Cleaning and maintenance of such systems to recommended standards should be performed regularly and where appropriate, the installation of HEPA filters can effectively mitigate microbial contamination in the public areas of hospitals.

Very few zircon-bearing, kimberlite-hosted mantle eclogite xenoliths have been identified to date; however, the zircon they contain is crucial for our understanding of subcratonic lithospheric mantle evolution and eclogite genesis. In this study, we constrain the characteristics of zircon from mantle eclogite xenoliths based on existing mineralogical and geochemical data from zircons from different geological settings, and on the inferred origin of mantle eclogites. Given the likely origin and subsequent evolution of mantle eclogites, we infer that the xenoliths can contain zircons with magmatic, metamorphic and xenogenic (i.e. kimberlitic zircon) origins. Magmatic zircon can be inherited from low-pressure mafic oceanic crust precursors, or might form during direct crystallization of eclogites from primary mantle-derived melts at mantle pressures. Metamorphic zircon within mantle eclogites has a number of possible origins, ranging from low-pressure hydrothermal alteration of oceanic crustal protoliths to metasomatism related to kimberlite magmatism. This study outlines a possible approach for the identification of inherited magmatic zircon within subduction-related mantle eclogites as well as xenogenic kimberlitic zircon within all types of mantle eclogites. We demonstrate this approach using zircon grains from kimberlite-hosted eclogite xenoliths from the Kasai Craton, which reveals that most, if not all, of these zircons were most likely incorporated as a result of laboratory-based contamination.

Cinnamomum chago is a woody species of the family Lauraceae endemic to Yunnan province, China, previously known from only one location, and categorized as a Plant Species with Extremely Small Population. We surveyed to determine the distribution and population size of C. chago, characterize its habitat, identify any threats, assess its conservation status, and provide guidelines for its management and conservation. During 2014–2017 we found only 64 mature C. chago, in five locations. These small, fragmented populations occur along Lancang River in Dali Prefecture at altitudes of 2,200–2,400 m. The species' extent of occurrence is c. 923 km2, with an area of occupancy of c. 60 km2. The habitat of the species has been degraded by expansion of pastoral activities and deforestation. We recommend categorization of C. chago as Endangered on the IUCN Red List, prevention of the collection of seeds and wood of the species, protection and monitoring, and ex situ propagation for future reintroductions.

Several studies have suggested that higher carotenoid levels may be beneficial for atherosclerosis patients, but few studies have examined this relationship in the Chinese population. This cross-sectional study examined the association between the levels of carotenoids in diet and serum and carotid intima–media thickness (IMT) in Chinese adults aged 50–75 years in Guangzhou, China. Dietary intake was assessed using a FFQ. HPLC was used to assay the serum concentrations of α-carotene, β-carotene, lutein+zeaxanthin, β-cryptoxanthin and lycopene. The IMT at the common carotid artery (CCA) and bifurcation of the carotid artery was measured by B-mode ultrasound. A total of 3707 and 2947 participants were included in the analyses of dietary and serum carotenoids. After adjustment for demographic, socio-economic and lifestyle factors, all the serum carotenoids levels except lycopene were found to be inversely associated with the IMT at the CCA and bifurcation (Ptrend<0·001 to 0·013) in both men and women. The absolute mean differences in the IMT between the subjects in the extreme quartiles of serum carotenoid levels were 0·034 mm (α-carotene), 0·037 mm (β-carotene), 0·032 mm (lutein+zeaxanthin), 0·030 mm (β-cryptoxanthin), 0·015 mm (lycopene) and 0·035 mm (total carotenoids) at the CCA; the corresponding values were 0·025, 0·053 0·043, 0·050, 0·011 and 0·042 mm at the bifurcation. The favourable associations were also observed between dietary carotenoids (except lycopene) and the CCA IMT. In conclusion, elevated carotenoid levels in diet and serum are associated with lower carotid IMT values (particular at the CCA) in Chinese adults.

In this study, the effects of Sm on the microstructure and corrosion resistance of hot-extruded AZ61 magnesium alloys were investigated by optical microscopy, scanning electron microscopy, and transmission electron microscopy. The results showed that uniformly dispersed Al2Sm particles with size of ∼2 μm were discovered in the hot-extruded AZ61 magnesium alloy sample modified with 1.0 wt% Sm, which promoted dynamic recrystallization grain growth during the hot-extruded process, gradually increasing the grain of the alloy as Sm content increased. The morphology of the corroded surface and the corrosion rate of the hot-extruded AZ61 magnesium alloy both were significantly improved after Sm addition. The alloy sample modified with 2.0 wt% Sm after immersion in 3.5 wt% NaCl solution for 12 h showed minimum corrosion rate value, 3.1 mg/cm2 day, which is only 3.7% of the corrosion rate of unmodified alloy (82 mg/cm2 day).

Twins could play a crucial role in our understanding of genetic contributions to numerous etiologically complex disorders. In China, although adult twins are relatively rare, twins will become increasingly available due to increasing twin birth rates. Thus, child twin data will be a valuable resource to contribute to the field of child and adolescent psychopathology. The first twin database of children aged from 6 to 16 was established in Chongqing, R.P., China. In this article, we will discuss our experiences in establishing the twin database, completed in three steps — the first step being to search and identify twins, the second being to keep contact with the twins and the final being to seek cooperation with the twin families, and its future prospects. Our twin database has proven to be an efficient method for the investigation and data collection of twin children in China. The results of our present study suggest that the inclusion of twin information in the residence registration of the public security bureaus in the future may ensure a smooth run of research based on the demographic resources. We propose that school networks may be adopted as the preferred method of collection of twin records for future studies.

During diabetes, structural and functional changes in the alimentary tract are known to take place resulting in an increased absorption of intestinal glucose and alterations in the activities of brush-border disaccharidases. To elucidate the effect of administrating polysaccharide from Gynura divaricata (PGD) on disaccharidase activities, the specific activities of intestinal disaccharidases, namely sucrase, maltase and lactase, were measured in streptozotocin-induced diabetic rats. Normal control and diabetic rats were treated by oral administration with PGD. Specific activities of intestinal disaccharidases were increased significantly during diabetes, and amelioration of the activities of sucrase and maltase during diabetes was clearly visible by the treatment with PGD. However, the increased activity of lactase during diabetes mellitus was remarkably alleviated by the administration of PGD only in the duodenum. Meanwhile, oral sucrose tolerance tests demonstrated that PGD alleviated the hyperglycaemia during diabetes mellitus, resulting from the amelioration in the activities of intestinal disaccharidases. The present investigation suggests that PGD exerted an anti-diabetic effect partly via inhibiting the increased intestinal disaccharidase activities of diabetic rats. This beneficial influence of administration of PGD on intestinal disaccharidases clearly indicates their helpful role in the management of diabetes.

Transgenes integrated into mammalian cells are silenced rapidly. This phenomenon correlates with repressed chromatin structure marked by histone hypoacetylation. This study investigated the effect of trichostatin A (TSA; a histone-deacetylase inhibitor) on EGFP expression in transfected cells and embryonic development after somatic cell nuclear transfer (SCNT). Porcine adult fibroblasts were transfected with a pEGFP-C1 vector. Then transfected cells, donor cells for SCNT, were pretreated with TSA, with the untreated cells being used as the control. Expression of EGFP in donor cells and reconstructed embryos was detected when exposed to blue light. Results showed that the percentage of EGFP-positive cells significantly increased when the transfected cells were treated with TSA and the increased expression of EGFP was sustained to at least the morula stage. In addition, the cytotoxic effect of TSA on the transfected cells was dose dependent. In conclusion, TSA can rescue the silenced EGFP gene. Even after transferring the TSA-treated cells to enucleated recipient oocytes, TSA retained the ability to rescue a silenced EGFP gene. In addition, TSA had an impact on cell proliferation.

In this paper, the ion jet generation from the interaction of an ultraintense laser pulse and a rear-side concave target is investigated analytically using a simple fluid model. We find that the ion expanding surface at the rear-side is distorted due to a strong charge-separation field, and that this distortion becomes dramatic with a singular cusp shown on the central axis at a critical time. The variation of the transverse ion velocity and the relative ion density diverge on the cusp, signaling the emergence of an on-axis ion jet. We have obtained analytical expressions for the critical time and the maximum velocity of the ion jet, and suggested an optimum shape for generating a collimated energetic ion jet. The above theoretical analysis has been verified by particle-in-cell (PIC) numerical simulations.

In vitro bulb scales of Lilium longiflorum×L. formosanum were used as explants to develop a highly efficient regeneration system. A high regeneration rate (100%) was reached through organogenesis on basal Murashige and Skoog (MS) medium supplemented with 1.0 mg/l 6-benzylaminopurine (6-BA) and 1.0 mg/l naphthaleneacetic acid (NAA). A genetic transformation system for the lily was developed using an Agrobacterium tumefaciens-mediated method. An improved genetic transformation rate (12‰) was obtained when the explants were pre-cultured for 3 days, immersed in bacterial suspension (OD600≈0.8) for 5 min, and co-cultivated for 5 days. The binary vector pBI121 containing Zm401, a maize pollen-specific gene, was introduced into the Agrobacterium strain LBA4404 and transformed into the explants using the genetic transformation system. Gene integration into the lily genome was confirmed by polymerase chain reaction (PCR) and PCR–Southern analysis. These results could lead to the production of new pollenless lily plants.