Heterogeneous Photocatalytic Ring Expansion of Cyclic Ketones for the Construction of Medium-Sized Lactams.

Construction of medium-sized ring compounds remains challenging in synthetic chemistry. Herein, we describe the synthesis of medium-sized lactams via a photoinduced ring expansion of benzo-fused cyclic ketones using graphitic carbon nitride (g-C3N4) as a photocatalyst. The ring expansion protocol provided an efficient access to 8-10-membered lactams in good yields and displayed good tolerance to a range of functional groups. The mechanism studies revealed that the photochemical reaction proceeds via an intermediary of a nitrogen radical, which is generated through an oxidative hydrogen atom transfer (HAT) process.

MiR-495/IGF-1/AKT Signaling as a Novel Axis Is Involved in the Epithelial-to-Mesenchymal Transition of Oral Squamous Cell Carcinoma.

PURPOSE: Increasing evidence suggests that aberrant expression of miR-495 is associated with the progression of various cancers. The aim of this study was to investigate the function and underlying mechanism of miR-495 in oral squamous cell carcinoma (OSCC). MATERIALS AND METHODS: OSCC specimens and oral cancer cell lines, as well as the OSCC microRNA expression profile from the Gene Expression Omnibus database, were used to detect the expression of miR-495 in OSCC. Cell proliferation, migration, and invasion assays were performed to analyze the function of miR-495. Bioinformatics and luciferase reporter assays were used to identify the target gene of miR-495. Pearson analysis was carried out to investigate the correlation between miR-495 and insulin-like growth factor 1 (IGF1) or AKT levels. Transfection of pcDNA3.1 vector and small interfering RNA was performed to overexpress or downregulate the expression of IGF1. OSCC xenografts in mice were constructed to validate the function and mechanism of miR-495 in vivo. RESULTS: MiR-495 was downregulated in OSCC tissues and cell lines, and it markedly inhibited cell proliferation, migration, and invasion, as well as epithelial-to-mesenchymal transition (EMT)-related proteins of OSCC cells. IGF1 was identified as a direct target gene of miR-495. Besides, AKT was confirmed to be regulated by miR-495/IGF-1 signaling, and miR-495 was negatively correlated with IGF1 and AKT in OSCC. In vivo, miR-495 inhibited the growth and EMT-related proteins of OSCC xenografts in mice. CONCLUSIONS: The miR-495/IGF-1/AKT signaling axis played a tumor-suppressive role in OSCC by regulating cell proliferation, invasion, and migration, as well as EMT.

miRNA-101 Targets TGF-ßR1 to Retard the Progression of Oral Squamous Cell Carcinoma.

Despite the considerable knowledge on the involvement of microRNA-101 (miR-101) in the evolution of oral squamous cell carcinoma (OSCC), the underlying mechanisms remain obscure. In this study, miR-101 expression was markedly downregulated in the OSCC cell lines and tissues. Cell counting kit-8 (CCK-8), ethynyl deoxyuridine (EdU), and colony formation assays showed that miR-101 inhibited the proliferation of OSCC cells. Flow cytometry and caspase 3 activity assays indicated that miR-101 induced OSCC cell apoptosis. Transwell assays demonstrated that this miRNA also repressed OSCC cell migration and invasion. Moreover, tube formation assay showed that miR-101 abated the proangiogenesis of OSCC cells. Dual-luciferase reporter assay confirmed that miR-101 directly targeted transforming growth factor-ß receptor 1 (TGF-ßR1) in OSCC. Ectopic expression of TGF-ßR1 counteracted the effects of miR-101 on the OSCC cell characteristics. Thus, miR-101 significantly abolished the proliferation, motility, and proangiogenesis of OSCC cells and induced their apoptosis by targeting TGF-ßR1. These results imply the potential application of miR-101 in OSCC treatment.

In-situ Cu Coating on Steel Surface after Oxidizing at High Temperature.

Almost all copper in scrap steel is recovered, so research on copper-bearing steel has profound practical significance. The surface enrichment of copper occurs in all copper-bearing steels studied in this paper after being heated at high temperature. In-situ oxidation-induced copper coatings were discovered on the descaled copper-bearing steels after heating at around 1150 °C for 2 h in air. Scattered copper precipitates in or under rust after heating at a lower temperature. A new concept was created using in-situ composites prepared by direct oxidation of matrix, and there was no bonding problem found between the coating and the matrix. The enrichment form of copper in steel is related to the oxidation rate, oxidation time, heating temperature and copper content.

Size-related bacterial diversity and tetracycline resistance gene abundance in the air of concentrated poultry feeding operations.

Concentrated animal-feeding operations (CAFOs) are considered a source of airborne human pathogens and antibiotic resistance genes. Although bacterial abundance and diversity have been well studied, limited information on the size distribution of bioaerosols has prevented a clear understanding of the health effects of exposure to bioaerosols from CAFOs. Here, different sizes of particles were sampled from the inside and outside of atmospheric environments of layer and broiler feeding operations using 8-stage Andersen samplers. The quantitative real-time polymerase chain reaction (qPCR) and 16S rDNA-based sequencing were used to analyze the characteristics of biological abundance and diversity, respectively, according to size. The results indicated that size-related differences occurred in terms of airborne bacterial richness, diversity, and concentration at poultry-feeding operations. The richness of biological genera in the urban atmospheric environment was lower than in concentrated poultry-feeding operations. The biological diversity of airborne bacterial genera, including genera associated with potential pathogens, varied according to size. The bacterial lineages of bioaerosols present in the 7 size stages for layers clustered apart from those for broilers, suggesting that the type of poultry house is a more important factor than the particle size in shaping the microbial communities. In most cases, the concentrations of the 16S rDNA, Escherichia coli, tetW, and tetL genes increased as the particle size increased, with the geometric mean diameters varying from 4.7 to 5.8 µm. These results regarding the size-related differences in the diversity and abundance of bioaerosols will facilitate a better understanding of the potential health impact on both poultry and humans working in such environments.

Concentration and size distribution of viable bioaerosols during non-haze and haze days in Beijing.

Accumulation of airborne particulate matter (PM) has profoundly affected the atmospheric environment of Beijing, China. Although studies on health risks have increased, characterization of specific factors that contribute to increased health risks remains an area of needed exploration. Chemical composition studies on PM can readily be found in the literature but researches on biological composition are still limited. In this study, the concentration and size distribution of viable airborne bacteria and fungi were determined in the atmosphere from May to July 2013 in Beijing, China. Samples were collected during non-haze days and haze days based on the value of air quality index (AQI) PM2.5. Multiple linear regression results indicated that concentrations of viable bioaerosol exhibited a negative correlation with PM2.5 (AQI) ranging from 14 to 452. There was a little difference in size distribution of bioaerosol between non-haze and haze days that all airborne bacteria showed skewed trends toward larger sizes and airborne fungi followed a Gaussian distribution. Spearman's correlation analysis showed that a fraction of bioaerosol with fine and coarse particles had negative and positive relations with PM2.5 (AQI), respectively. Moreover, the temporal variation of d g (aerodynamic diameter) of bioaerosol with PM2.5 (AQI) fluctuated from 9:00 to 21:00, which suggested that their deposition pattern would vary during a day. The primary research in this study implied that aerodynamic size variation should be considered in assessing the bioaerosol exposure during haze weather.

Diversity and population structure of a dominant deciduous tree based on morphological and genetic data.

Knowledge of the genetic diversity and structure of tree species across their geographic ranges is essential for sustainable use and management of forest ecosystems. Acer grosseri Pax., an economically and ecologically important maple species, is mainly distributed in North China. In this study, the genetic diversity and population differentiation of 24 natural populations of this species were evaluated using sequence-related amplified polymorphism markers and morphological characters. The results show that highly significant differences occurred in 32 morphological traits. The coefficient of variation of 34 characters was 18.19 %. Principal component analysis indicated that 18 of 34 traits explained 60.20 % of the total variance. The phenotypic differentiation coefficient (VST) was 36.06 % for all morphological traits. The Shannon-Wiener index of 34 morphological characters was 6.09, while at the population level, it was 1.77. The percentage of polymorphic bands of all studied A. grosseri populations was 82.14 %. Nei's gene diversity (He) and Shannon's information index (I) were 0.35 and 0.50, respectively. Less genetic differentiation was detected among the natural populations (GST = 0.20, ΦST = 0.10). Twenty-four populations of A. grosseri formed two main clusters, which is consistent with morphological cluster analysis. Principal coordinates analysis and STRUCTURE analysis supported the UPGMA-cluster dendrogram. There was no significant correlation between genetic and geographical distances among populations. Both molecular and morphological data suggested that A. grosseri is rich in genetic diversity. The high level of genetic variation within populations could be affected by the biological characters, mating system and lifespan of A. grosseri, whereas the lower genetic diversity among populations could be caused by effective gene exchange, selective pressure from environmental heterogeneity and the species' geographical range.

[Concentration and size distribution of bioaerosols at non-haze and haze days in Beijing].

In recent years, haze has been observed frequently in Beijing. Haze was one of the atmospheric phenomena caused by the accumulation of particulate matter. As an important fraction of particular matter, bioaerosol could potentially cause significantly negative health effects. In this study, we detected the concentration and size distribution of viable bioaerosol during non-haze and haze days, analyzed correlation of viable bioaerosol with the ambient temperature and relative humidity using Spearman's correlation coefficient and finally detected the changing of size distribution of viable bioaerosol in summer and winter. Results indicated that concentrations of viable bioaerosol exhibited a negative correlation with Air Quality Index (AQI) of PM2.5 and positive correlation with temperature. Relative humidity had a negative correlation with airborne bacteria while positive correlation with airborne fungi. The highest concentration of airborne bacteria and fungi were detected at size arrange of 4.5-7.0 µm and 2. 1-3.3 µm in the winter, respectively. In the summer, both the highest concentration of airborne bacteria and fungi were observed at size arrange of 3.3-4.5 µm. The results of this study will provide the basis data for hazard evaluation of bioaerosol on human health at non-haze and haze days.

[Clinical and radiographic study of the fractured immature anterior permanent teeth after pulpotomy].

OBJECTIVE: To observe the outcome of the fractured immature anterior permanent teeth after pulpotomy by X-ray measurement. METHODS: A total of 31 (25 cases) fractured immature anterior permanent teeth after pulpotomy was reviewed. Radiographic measurements were performed on 12 cases with unilateral fractured central incisors and completely formed roots after pulpotomy and 100 (50 subjects) healthy maxillary central incisors. RESULTS: The roots development continued after pulpotomy, and the root length and periapical configuration were both similar to the healthy teeth, but some root canals became narrow or even nearly obturated at the root apex. There was no significant difference in root canal width between healthy right and left maxillary central incisors at the site of 1/4 [right: (0.67 +/- 0.14) mm, left: (0.66 +/- 0.12) mm, P > 0.05], 1/2 [right: (1.05 +/- 0.19) mm, left: (1.04 +/- 0.17) mm, P > 0.05], 3/4 [right: (1.78 +/- 0.34) mm, left: (1.76 +/- 0.30) mm, P > 0.05] of root, but the root canal width of the fractured incisors at the same site was significantly different from that of the contralateral healthy incisor, the 1/4 site pulpotomy: (0.70 +/- 0.23) mm, control: (0.99 +/- 0.17) mm, the 1/2 site pulpotomy: (1.16 +/- 0.24) mm, control: (1.51 +/- 0.25) mm; the 3/4 site pulpotomy: (1.96 +/- 0.34) mm, control: (2.24 +/- 0.36) mm. CONCLUSIONS: There was a tendency that the root canals of fractured teeth after pulpotomy became narrowed and obturated. It should not be followed up for too long to perform root canal treatment when roots completely formed.

[The histological and immunohistochemical manifestation of the immature anterior teeth after pulpotomy].

OBJECTIVE: To observe the histological and immunohistochemical characteristics of the pulp of teeth after pulpotomy. METHODS: Twenty-nine permanent anterior teeth with completely formed roots after pulpotomy due to dental trauma were selected. Thirty permanent premolars with completely formed roots served as control, which were extracted for orthodontic treatment. HE stain and immunohistochemical study of collagen I and collagen III were performed on the root pulp of these two groups. RESULTS: There were degenerative changes in root pulp of the teeth after pulpotomy, such as vacuolization and homogenization of the odontoblasts, cell reduction, fibrosis, hyaline degeneration and calcification. In healthy root pulp, collagen I had a dispersed distribution, calcification substance was stained positive, but collagen III weakly stained in the extreme at peripheric pulp, and calcification substance stained negative. While in pulp of teeth after pulpotomy, both types of collagens had increased expression, fibers aggregated forming thick fiber bundles. In the wall of blood vessels collagen I had increased expression, but collagen III decreased. CONCLUSIONS: The root pulp below dentin bridge after pulpotomy was different from the healthy pulp, and there were some histological degenerative changes in the pulp of the immature anterior teeth after pulpotomy. It is suggested that root canal treatment should eventually be performed on these teeth.