Reverse transcription quantitative real-time PCR (RT-qPCR) is a sensitive technique for quantifying gene expression, but its success depends on the stability of the reference gene(s) used for data normalization. Only a few studies on validation of reference genes have been conducted in fruit trees and none in banana yet. In the present work, 20 candidate reference genes were selected, and their expression stability in 144 banana samples were evaluated and analyzed using two algorithms, geNorm and NormFinder. The samples consisted of eight sample sets collected under different experimental conditions, including various tissues, developmental stages, postharvest ripening, stresses (chilling, high temperature, and pathogen), and hormone treatments. Our results showed that different suitable reference gene(s) or combination of reference genes for normalization should be selected depending on the experimental conditions. The RPS2 and UBQ2 genes were validated as the most suitable reference genes across all tested samples. More importantly, our data further showed that the widely used reference genes, ACT and GAPDH, were not the most suitable reference genes in many banana sample sets. In addition, the expression of MaEBF1, a gene of interest that plays an important role in regulating fruit ripening, under different experimental conditions was used to further confirm the validated reference genes. Taken together, our results provide guidelines for reference gene(s) selection under different experimental conditions and a foundation for more accurate and widespread use of RT-qPCR in banana.

Background: As a global pandemic, COVID-19 has aroused great concern in the last few months and a growing number of related researches have been published. Therefore, a bibliometric analysis of these publications may provide a direction of hot topics and future research trends. Methods:The global literatures about COVID-19 published between 2019 and 2020 were scanned in the Web of Science collection database. "COVID-19" "Novel Coronavirus" "2019-nCoV" and "SARS-CoV-2" were used as the keywords to reach the relevant publications. VOSviewer was applied to perform the bibliometric analysis of these articles.Results: Totally 3,626 publications on the topic of COVID-19 were identified and "COVID-19" with a total link strength of 2,649 appeared as the most frequent keyword, which had a strong link to "pneumonia" and "epidemiology". The mean citation count of the top 100 most cited articles was 96 (range, 26-883). Most of them were descriptive studies and concentrated on the clinical features. The highest-ranking journal was British medical journal with 211 publications and the most cited journal was Lancet with 2,485 citation counts. Eleven articles written by Christian Drosten from Berlin Institute of Virology have been cited for 389 times and 40 articles from Chinese Academy of Sciences have been cited for 1,597 times which are the most cited author and organization. The number of collaborators with China is 44 and the total link strength is 487. The main partners of China are USA, England and Germany. The published literatures have focused on three topics: disease management, clinical features and pathogenesis. Conclusions:The current growth trends predict a large increase in the number of global publications on COVID-19. China made the most outstanding contribution within this important field. Disease treatment, spike protein and vaccine may be hotspots in the future.

Reverse transcription quantitative real-time PCR (RT-qPCR), a sensitive technique for quantifying gene expression, depends on the stability of the reference gene(s) used for data normalization. Only a few studies on reference genes have been done in fruit trees and none in litchi. In the present study, seven frequently used candidate reference genes, including actin (ACTIN), glyceraldehyde-3-phosphate-dehydrogenase (GADPH), elongation factor 1-alpha (EF-1α), poly ubiquitin enzyme (UBQ), α-tubulin (TUA), β-tubulin (TUB) and RNA polymerase-II transcription factor (RPII), were evaluated for their expression stability in litchi. A total of 78 samples, including different varieties, tissues, organs, developmental stages and treatments, such as NAA, shading and girdling plus defoliation, were addressed in this analysis. Our results showed that GAPDH was the most suitable reference gene among all the tested samples, different organs and NAA treatment. ACTIN was stably expressed in varieties and fruit developmental stages. RPII and UBQ exhibited better expression stability in tissues. EF-1α was the most stable gene in shading and girdling plus defoliation treatments. Moreover, using combination of two genes as reference genes might improve the reliability of gene expression by RT-qPCR in litchi. A better combination was GAPDH + EF-1α or GAPDH + ACTIN for all the examined samples. In addition, the validated reference genes were further relied on to quantify the expression of an interested gene, LcARF13 under different experimental conditions. These results first provide guidelines for reference genes selection under different experimental conditions and also a foundation for more accurate and widespread use of RT-qPCR in litchi.

Key Points Question Can multiparametric magnetic resonance imaging (MRI) radiomic profiles be used to predict axillary lymph node metastasis (ALNM) and disease-free survival (DFS) in patients with early-stage breast cancer? Findings In this prognostic study that included 1214 patients, 2 clinical-radiomic nomograms were developed that accurately predicted ALNM and stratified patients into low-risk and high-risk groups for DFS. Meaning In this study, clinical-radiomic nomograms were useful in clinical decision-making associated with personalized selection of surgical interventions and therapeutic regimens for patients with early-stage breast cancer.

In this work, we report a new family of viologen-based ionic porous hybrid polymers (V-iPHPs) with task-specific multiple catalytic active sites toward efficient catalytic fixation of carbon dioxide (CO2) to value-added cyclic carbonates. The targeted V-iPHPs were fabricated by the solvothermal Heck reaction between two newly designed viologen ionic linkers and octavinylsilsesquioxane (VPOSS). The obtained V-iPHPs possess tunable surface areas (150–562 m2 g–1) and pore volumes (0.41–1.82 cm3 g–1) along with adjustable ionic sites (0.92–1.47 mmol g–1). Especially, a plenty of silanol (Si–OH) groups are in situ formed via breaking polyhedral oligomeric silsesquioxane cages during the synthetic process. The typical catalyst V-iPHP-1 exhibits remarkable metal-free heterogeneous catalytic activities in the CO2 fixation with diverse epoxide substrates under very mild conditions. Besides, the heterogeneous catalyst V-iPHP-1 could be easily recovered with good reusability. The excellent catalytic performance could be assigned to the synergistic catalysis of hydrogen bond donors Si–OH groups and Br– anions, abundant mesoporosities, and the hydrophobic reaction microenvironment.

Arsenic is a ubiquitous contaminant in drinking water. Whereas arsenic can be directly hepatotoxic, the concentrations/doses required are generally higher than present in the US water supply. However, physiological/biochemical changes that are alone pathologically inert can enhance the hepatotoxic response to a subsequent stimulus. Such a '2-hit' paradigm is best exemplified in chronic fatty liver diseases. Here, the hypothesis that low arsenic exposure sensitizes liver to hepatotoxicity in a mouse model of non-alcoholic fatty liver disease was tested. Accordingly, male C57Bl/6J mice were exposed to low fat diet (LFD; 13% calories as fat) or high fat diet (HFD; 42% calories as fat) and tap water or arsenic (4.9 ppm as sodium arsenite) for ten weeks. Biochemical and histologic indices of liver damage were determined. High fat diet (± arsenic) significantly increased body weight gain in mice compared with low-fat controls. HFD significantly increased liver to body weight ratios; this variable was unaffected by arsenic exposure. HFD caused steatohepatitis, as indicated by histological assessment and by increases in plasma ALT and AST. Although arsenic exposure had no effect on indices of liver damage in LFD-fed animals, it significantly increased the liver damage caused by HFD. This effect of arsenic correlated with enhanced inflammation and fibrin extracellular matrix (ECM) deposition. These data indicate that subhepatotoxic arsenic exposure enhances the toxicity of HFD. These results also suggest that arsenic exposure might be a risk factor for the development of fatty liver disease in human populations.

Two-in-one hydroxyl-incorporated imidazolium ionic network was constructed in one-pot quaternization for enhancing synergistic catalytic conversion of CO2 under mild conditions.

The clinical significance and mechanisms of TET2 are not well defined in myeloid malignancies. We detected TET2 mutations and assayed its catalyzing conversion product 5-hydroxymethylcytosine (5-hmC) in 61 Chinese patients with MDS. Ten patients were identified to have TET2 mutations (16.4%). 5-hmC levels in patients with MDS with TET2 mutations were significantly lower than in those without mutations, and CD34+ cells of patients with MDS exhibited a lower 5-hmC content than that of controls. TET2 expression and 5-hmC in patients with MDS with P15 methylation were both significantly lower than in those without P15 methylation. We did not observe a correlation between TET2 mutations and overall survival (OS) in MDS. Interestingly, we found that patients with MDS with higher 5-hmC levels or in lower risk groups of the Revised International Prognostic Scoring System (IPSS-R) had a longer overall survival, suggesting that 5-hmC levels may be a new molecular marker for prognostic assessment of MDS and that revised IPSS criteria are also applicable to the risk categories of Chinese patients with MDS.