A META-ANALYTIC REVIEW OF SOCIAL MEDIA STUDIES

Social media such as social networking sites, blogs, micro-blogs, Wikis, are increasingly and widely used in our daily lives. In the information system (IS) discipline, social media have become a hot research area and draw the attention of many scholars. The paper systematically reviewed social media studies published in Association for Information Systems (AIS) listed top 20 journals from 2009 to 2013. The publication time, journal preferences, research objects and research topics are discussed. Generally, the current social media studies including four areas, namely user, management, technology and information. Each area has distinct focuses and topics. By thoroughly analyzing the research topics, the authors formulate our projections and recommendations for future social media studies

Thiopeptide Antibiotics Exhibit a Dual Mode of Action against Intracellular Pathogens by Affecting Both Host and Microbe

SummaryThiostrepton (TSR) is an archetypal thiopeptide antibiotic possessing a quinaldic acid (QA) moiety in the side ring system. According to the mechanism of TSR previously known to target bacterial ribosome, we recently designed and biosynthesized several TSR derivatives that varied in QA substitution. Utilizing these thiopeptide antibiotics to treat the intracellular pathogen Mycobacterium marinum, we herein report a novel mode of action of TSRs, which induce ER stress-mediated autophagy to enhance host cell defense. This intracellular response, which is sensitive to the modification of the QA group, serves as an indirect but unignorable mechanism for eliminating intracellular pathogens. TSRs are thus the only type of antibiotics, to our knowledge, with the dual action on both the parasitic bacteria and the infected host cells. The newly observed mechanism of TSRs may inspire the future change in the treatment of intracellular pathogens, by taking host response into account

Petrogenesis of Early Cretaceous intermediate-felsic dikes in the Jiaodong Peninsula, south-eastern North China Craton: Constraints from geochronology, geochemistry and Sr-Nd-Pb-Hf isotopes

Early Cretaceous dike swarms are widely developed in the Jiaodong Peninsula, NE China. In this study, we newly investigated the spatial-temporal distribution, petrography, geochronology and whole-rock geochemistry of the intermediate-felsic dikes from the Jiaobei terrane and the Sulu orogenic belt in the Jiadong Peninsula. The zircon U-Pb dating has constrained the timing of the emplacement of intermediate-felsic dikes to 128–108 Ma. The quartz diorite dikes in Jiaobei show adakitic geochemical features, including high SiO2 (66.3–67.5 wt%) contents and high Sr/Y (76–149) and La/Yb (41–91) ratios. The combination of a series of isotopic data, including initial 87Sr/86Sr ratios (0.7098–0.7104) and negative εNd(t) (−20.1 to −14.7) and zircon εHf(t) values (−19.9 to −9.5), indicates that these quartz diorite dikes were likely derived from partial melting of thickened ancient lower crust with involvement of underplated mafic magmas. Additionally, the diorite dikes in Jiaobei and those in Sulu show similar chemical compositions, as both yield the high-Mg andesite (or andesitic rocks) (HMAs) characteristics with a high Mg# value (60–72), high MgO, Cr, and Ni contents, and low Na2O (average = 3.25 wt%) contents. They also exhibit crustal geochemical signatures, such as depletion in Nb, Ta, and Ti, but enrichment in Th and U; high initial 87Sr/86Sr ratios (0.7063–0.7094), and low εNd(t) (−16.7 to −9.6) and εHf(t) values (−29.4 to −9.8). The entire geochemical evidences imply that they derived from the partial melting of mantle wedge peridotite metasomatized by hydrous fluids from the subduction of the oceanic slab with marine sediments. In combination with the Early Cretaceous intrusions and mafic dikes at Jiaodong, the intermediate-felsic dikes represent a magmatic response to lithospheric thinning resulted from the prolonged thermo-mechanical-chemical erosion processes caused by slab rollback of the Paleo-Pacific plate

Dynamic Responses of Continuous Girder Bridges with Uniform Cross-Section under Moving Vehicular Loads

To address the drawback of traditional method of investigating dynamic responses of the continuous girder bridge with uniform cross-section under moving vehicular loads, the orthogonal experimental design method is proposed in this paper. Firstly, some empirical formulas of natural frequencies are obtained by theoretical derivation and numerical simulation. The effects of different parameters on dynamic responses of the vehicle-bridge coupled vibration system are discussed using our own program. Finally, the orthogonal experimental design method is proposed for the dynamic responses analysis. The results show that the effects of factors on dynamic responses are dependent on both the selected position and the type of the responses. In addition, the interaction effects between different factors cannot be ignored. To efficiently reduce experimental runs, the conventional orthogonal design is divided into two phases. It has been proved that the proposed method of the orthogonal experimental design greatly reduces calculation cost, and it is efficient and rational enough to study multifactor problems. Furthermore, it provides a good way to obtain more rational empirical formulas of the DLA and other dynamic responses, which may be adopted in the codes of design and evaluation

Lipid and glucose metabolism in senescence

Senescence is an inevitable biological process. Disturbances in glucose and lipid metabolism are essential features of cellular senescence. Given the important roles of these types of metabolism, we review the evidence for how key metabolic enzymes influence senescence and how senescence-related secretory phenotypes, autophagy, apoptosis, insulin signaling pathways, and environmental factors modulate glucose and lipid homeostasis. We also discuss the metabolic alterations in abnormal senescence diseases and anti-cancer therapies that target senescence through metabolic interventions. Our work offers insights for developing pharmacological strategies to combat senescence and cancer

Selective inhibition of mTORC1 in tumor vessels increases antitumor immunity.

A tumor blood vessel is a key regulator of tissue perfusion, immune cell trafficking, cancer metastasis, and therapeutic responsiveness. mTORC1 is a signaling node downstream of multiple angiogenic factors in the endothelium. However, mTORC1 inhibitors have limited efficacy in most solid tumors, in part due to inhibition of immune function at high doses used in oncology patients and compensatory PI3K signaling triggered by mTORC1 inhibition in tumor cells. Here we show that low-dose RAD001/everolimus, an mTORC1 inhibitor, selectively targets mTORC1 signaling in endothelial cells (ECs) without affecting tumor cells or immune cells, resulting in tumor vessel normalization and increased antitumor immunity. Notably, this phenotype was recapitulated upon targeted inducible gene ablation of the mTORC1 component Raptor in tumor ECs (RaptorECKO). Tumors grown in RaptorECKO mice displayed a robust increase in tumor-infiltrating lymphocytes due to GM-CSF-mediated activation of CD103+ dendritic cells and displayed decreased tumor growth and metastasis. GM-CSF neutralization restored tumor growth and metastasis, as did T cell depletion. Importantly, analyses of human tumor data sets support our animal studies. Collectively, these findings demonstrate that endothelial mTORC1 is an actionable target for tumor vessel normalization, which could be leveraged to enhance antitumor immune therapies

Transcriptomic analysis reveals ethylene signal transduction genes involved in pistil development of pumpkin

Development of female flowers is an important process that directly affects the yield of Cucubits. Little information is available on the sex determination and development of female flowers in pumpkin, a typical monoecious plant. In the present study, we used aborted and normal pistils of pumpkin for RNA-Seq analysis and determined the differentially expressed genes (DEGs) to gain insights into the molecular mechanism underlying pistil development in pumpkin. A total of 3,817 DEGs were identified, among which 1,341 were upregulated and 2,476 were downregulated. The results of transcriptome analysis were confirmed by real-time quantitative RT-PCR. KEGG enrichment analysis showed that the DEGs were significantly enriched in plant hormone signal transduction and phenylpropanoid biosynthesis pathway. Eighty-four DEGs were enriched in the plant hormone signal transduction pathway, which accounted for 12.54% of the significant DEGs, and most of them were annotated as predicted ethylene responsive or insensitive transcription factor genes. Furthermore, the expression levels of four ethylene signal transduction genes in different flower structures (female calyx, pistil, male calyx, stamen, leaf, and ovary) were investigated. The ethyleneresponsive DNA binding factor, ERDBF3, and ethylene responsive transcription factor, ERTF10, showed the highest expression in pistils and the lowest expression in stamens, and their expression levels were 78- and 162-times more than that in stamens, respectively. These results suggest that plant hormone signal transduction genes, especially ethylene signal transduction genes, play an important role in the development of pistils in pumpkin. Our study provides a theoretical basis for further understanding of the mechanism of regulation of ethylene signal transduction genes in pistil development and sex determination in pumpkin

Multi-modal Single-Cell Analysis Reveals Brain Immune Landscape Plasticity during Aging and Gut Microbiota Dysbiosis

Phenotypic and functional plasticity of brain immune cells contribute to brain tissue homeostasis and disease. Immune cell plasticity is profoundly influenced by tissue microenvironment cues and systemic factors. Aging and gut microbiota dysbiosis that reshape brain immune cell plasticity and homeostasis has not been fully delineated. Using Cellular Indexing of Transcriptomes and Epitopes by sequencing (CITE-seq), we analyze compositional and transcriptional changes of the brain immune landscape in response to aging and gut dysbiosis. Discordance between canonical surface-marker-defined immune cell types and their transcriptomes suggest transcriptional plasticity among immune cells. Ly6C+ monocytes predominate a pro-inflammatory signature in the aged brain, while innate lymphoid cells (ILCs) shift toward an ILC2-like profile. Aging increases ILC-like cells expressing a T memory stemness (Tscm) signature, which is reduced through antibiotics-induced gut dysbiosis. Systemic changes due to aging and gut dysbiosis increase propensity for neuroinflammation, providing insights into gut dysbiosis in age-related neurological diseases