A study of the effect of ionization and illumination on morphologies of planetary nebulae

We carry out a modelling study of the effect of ionization and illumination on the morphologies of planetary nebulae (PNs), aiming to investigate the hypothesis of Kwok (2010) that the bipolar and multipolar lobes of PNs can be produced by leakage of UV photons into those directions. Using photoinization code, we construct a series of nebular models consisting of a dense envelope and cones of low density. The results show that the visible morphologies of PNs may be fundamentally different from their intrinsic structures. © 2012 International Astronomical Union.published_or_final_versio

Early real-time estimation of the basic reproduction number of emerging or reemerging infectious diseases in a community with heterogeneous contact pattern: Using data from Hong Kong 2009 H1N1 Pandemic Influenza as an illustrative example

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Leveraging per Image-Token Consistency for Vision-Language Pre-training

Most existing vision-language pre-training (VLP) approaches adopt cross-modal masked language modeling (CMLM) to learn vision-language associations. However, we find that CMLM is insufficient for this purpose according to our observations: (1) Modality bias: a considerable amount of masked tokens in CMLM can be recovered with only the language information, ignoring the visual inputs. (2) Under-utilization of the unmasked tokens: CMLM primarily focuses on the masked token but it cannot simultaneously leverage other tokens to learn vision-language associations. To handle those limitations, we propose EPIC (lEveraging Per Image-Token Consistency for vision-language pre-training). In EPIC, for each image-sentence pair, we mask tokens that are salient to the image (i.e., Saliency-based Masking Strategy) and replace them with alternatives sampled from a language model (i.e., Inconsistent Token Generation Procedure), and then the model is required to determine for each token in the sentence whether they are consistent with the image (i.e., Image-Text Consistent Task). The proposed EPIC method is easily combined with pre-training methods. Extensive experiments show that the combination of the EPIC method and state-of-the-art pre-training approaches, including ViLT, ALBEF, METER, and X-VLM, leads to significant improvements on downstream tasks

Social contacts and the locations in which they occur as risk factors for influenza infection

The interaction of human social behaviour and transmission is an intriguing aspect of the life cycle of respiratory viral infections. Although age-specific mixing patterns are often assumed to be the key drivers of the age-specific heterogeneity in transmission, the association between social contacts and biologically confirmed infection has not previously been tested at the individual level. We administered a questionnaire to participants in a longitudinal cohort survey of influenza in which infection was defined by longitudinal paired serology. Using a variety of statistical approaches, we found overwhelming support for the inclusion of individual age in addition to contact variables when explaining odds of infection: the best model not including age explained only 15.7% of the deviance, whereas the best model with age explained 23.6%. However, within age groups, we did observe an association between contacts, locations and infection: median numbers of contacts (or locations) reported by those infected were higher than those from the uninfected group in every age group other than the youngest. Further, we found some support for the retention of location and contact variables in addition to age in our regression models, with excess odds of infection of approximately 10% per additional 10 contacts or one location. These results suggest that, although the relationship between age and incidence of respiratory infection at the level of the individual is not driven by self-reported social contacts, risk within an age group may be.published_or_final_versio

The Ethanol Extract of Fructus trichosanthis Promotes Fetal Hemoglobin Production via p38 MAPK Activation and ERK Inactivation in K562 Cells

Pharmacological stimulation of fetal hemoglobin (HbF) expression may be a promising approach for the treatment of beta-thalassemia. In this study, the effects of Fructus trichosanthis (FT) were investigated in human erythroleukemic K562 cells for their gamma-globin mRNA and HbF-induction activities. The role of signaling pathways, including extracellular regulated protein kinase (ERK) and p38 mitogen-activated protein kinase (MAPK), was also investigated. It was found that the ethanol extract of FT significantly increased gamma-globin mRNA and HbF levels, determined by real-time reverse transcription polymerase chain reaction and enzyme linked immunosorbent assay, respectively, in dose- and time-dependent manner. Total Hb (THb) levels were also elevated in the concentrations without cytotoxicity (<80 μg mL−1). Pre-treatment with p38 MAPK inhibitor SB203580 blocked the stimulatory effects of FT extract in total and HbF induction. In contrast, no change in HbF was observed when treated with ERK inhibitor PD98059. Furthermore, FT ethanol extract activated p38 MAPK and inhibited ERK signaling pathways in K562 cells, as revealed in western blotting analysis. In addition, SB203580 significantly abolished p38 MAPK activation when the cells were treated with FT. In summary, the ethanol extract of FT was found to be a potent inducer of HbF synthesis in K562 cells. The present data delineated the role of ERK and p38 MAPK signaling as molecular targets for pharmacologic stimulation of HbF production upon FT treatment

Roles of Tumor Suppressor Signaling on Reprogramming and Stemness Transition in Somatic Cells

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Osteoprotective effects of Fructus Ligustri Lucidi aqueous extract in aged ovariectomized rats

<p>Abstract</p> <p>Background</p> <p><it>Fructus Ligustri Lucidi </it>(FLL) is a commonly used herb for treating bone disorders in Chinese medicine. The present study investigates the anti-osteoporotic activity of FLL aqueous extract in the model of postmenopausal bone loss in aged ovariectomized (OVX) female rats.</p> <p>Methods</p> <p>After eight weeks of treatment of FLL or water, the lumbar spine was scanned by peripheral quantitative computed tomography (pQCT). Effects of FLL water extract on osteogenic and adipogenic differentiations in rat mesenchymal stem cells (MSCs) were assessed by biochemical methods and staining.</p> <p>Results</p> <p>FLL aqueous extract significantly inhibited bone mineral density (BMD) loss in total, trabecular and cortical bones without affecting body weight and uterus wet weight. FLL extract significantly promoted osteogenesis and suppressed adipogenesis in MSCs as indicated by the elevated alkaline phosphatase activity, calcium deposition levels and decreased adipocyte number in a dose-dependent manner without cytotoxic effects. Real-time PCR analysis revealed significant increase of osteoprotegerin (OPG)-to-receptor activator for nuclear factor-κB ligand (RANKL) mRNA, indicating a decrease in osteoclastogenesis.</p> <p>Conclusion</p> <p>The present study demonstrates the osteoprotective effects of FLL aqueous extract on aged OVX rats, stimulation of osteogenesis, inhibition of adipogenesis and osteoclastogenesis in MSCs.</p

Temporal variation of human encounters and the number of locations in which they occur: a longitudinal study of Hong Kong residents

Patterns of social contact between individuals are important for the transmission of many pathogens and shaping patterns of immunity at the population scale. To refine our understanding of how human social behaviour may change over time, we conducted a longitudinal study of Hong Kong residents. We recorded the social contact patterns for 1450 individuals, up to four times each between May 2012 and September 2013. We found individuals made contact with an average of 12.5 people within 2.9 geographical locations, and spent an average estimated total duration of 9.1 h in contact with others during a day. Distributions of the number of contacts and locations in which contacts were made were not significantly different between study waves. Encounters were assortative by age, and the age mixing pattern was broadly consistent across study waves. Fitting regression models, we examined the association of contact rates (number of contacts, total duration of contact, number of locations) with covariates and calculated the inter- and intra-participant variation in contact rates. Participant age was significantly associated with the number of contacts made, the total duration of contact and the number of locations in which contact occurred, with children and parental-age adults having the highest rates of contact. The number of contacts and contact duration increased with the number of contact locations. Intra-individual variation in contact rate was consistently greater than inter-individual variation. Despite substantial individual-level variation, remarkable consistency was observed in contact mixing at the population scale. This suggests that aggregate measures of mixing behaviour derived from cross-sectional information may be appropriate for population-scale modelling purposes, and that if more detailed models of social interactions are required for improved public health modelling, further studies are needed to understand the social processes driving intra-individual variation