The progenitors of type Ia supernovae in the semidetached binaries with red giant donors

Context. The companions of the exploding carbon-oxygen white dwarfs (CO WDs) for producing type Ia supernovae (SNe Ia) are still not conclusively confirmed. A red-giant (RG) star has been suggested to be the mass donor of the exploding WD, named as the symbiotic channel. However, previous studies on the this channel gave a relatively low rate of SNe Ia. Aims. We aim to systematically investigate the parameter space, Galactic rates and delay time distributions of SNe Ia from the symbiotic channel by employing a revised mass-transfer prescription. Methods. We adopted an integrated mass-transfer prescription to calculate the mass-transfer process from a RG star onto the WD. In this prescription, the mass-transfer rate varies with the local material states. Results. We evolved a large number of WD+RG systems, and found that the parameter space of WD+RG systems for producing SNe Ia is significantly enlarged. This channel could produce SNe Ia with intermediate and old ages, contributing to at most 5% of all SNe Ia in the Galaxy. Our model increases the SN Ia rate from this channel by a factor of 5. We suggest that the symbiotic systems RS Oph and T CrB are strong candidates for the progenitors of SNe Ia.Comment: 8 pages, 6 figure

TNFα induces Ca2+ influx to accelerate extrinsic apoptosis in hepatocellular carcinoma cells

BACKGROUND: Tumor necrosis factor-α has been proven an effective anticancer agent in preclinical studies. However, the translation of TNFα from research to clinic has been blocked by significant systemic toxicity and limited efficacy at maximal tolerated dose, which need urgently to be solved. METHODS: The level of cytosolic Ca RESULTS: Here, we demonstrated that TNFα induced extracellular Ca CONCLUSIONS: Our study provides the evidence supporting a novel mechanism by which TNFα induces extracellular C

Spatial distribution of soil organic carbon stock in Moso bamboo forests in subtropical China

Moso bamboo (Phyllostachys heterocycla (Carr.) Mitford cv. Pubescens) is an important timber substitute in China. Site specific stand management requires an accurate estimate of soil organic carbon (SOC) stock for maintaining stand productivity and understanding global carbon cycling. This study compared ordinary kriging (OK) and inverse distance weighting (IDW) approaches to study the spatial distribution of SOC stock within 0–60cm using 111 soil samples in Moso bamboo forests in subtropical China. Similar spatial patterns but different spatial distribution ranges of SOC stock from OK and IDW highlighted the necessity to apply different approaches to obtain accurate and consistent results of SOC stock distribution. Different spatial patterns of SOC stock suggested the use of different fertilization treatments in Moso bamboo forests across the study area. SOC pool within 0–60cm was 6.46 and 6.22 Tg for OK and IDW; results which were lower than that of conventional approach (CA, 7.41 Tg). CA is not recommended unless coordinates of the sampling locations are missing and the spatial patterns of SOC stock are not required. OK is recommended for the uneven distribution of sampling locations. Our results can improve methodology selection for investigating spatial distribution of SOC stock in Moso bamboo forestsThis study was funded by Demonstration Project of Bamboo Forest of State Forest Administration ([2015]13), National Scientific Plan for Rural Area (Grant No. 2015BAD04B0203)S

Screening of alginate lyase-excreting microorganisms from the surface of brown algae

Additional file 1: Figure S1. Gram staining of the 12 alginate lyase-excreting bacterial strains

Regulation of the stability and transcriptional activity of NFATc4 by ubiquitination

AbstractNuclear factor of activated T cells (NFATc4) has been implicated as a critical regulator of the cardiac development and hypertrophy. However, the mechanisms for regulating NFATc4 stability and transactivation remain unclear. We showed that NFATc4 protein was predominantly ubiquitinated through the formation of Lysine 48-linked polyubiquitin chains, and this modification decreased NFATc4 protein levels and its transcriptional activity. Furthermore, activation of GSK3β markedly enhanced NFATc4 ubiquitination and decreased its transactivation, whereas inhibition of GSK3β had opposite effects. Importantly, ubiquitination and phosphorylation induced by GSK3β repressed NFATc4-dependent cardiac-specific gene expression. These results demonstrate that the ubiquitin–proteasome system plays an important role in regulating NFATc4 stability and transactivation.Structured summaryMINT-6798349:NFATc4 (uniprotkb:Q14934) physically interacts (MI:0218) with Ubiquitin (uniprotkb:P62988) by anti bait coimmunoprecipitation (MI:0006)MINT-6798334:NFATc4 (uniprotkb:Q14934) physically interacts (MI:0218) with Ubiquitin (uniprotkb:P62988) by anti tag coimmunoprecipitation (MI:0007)MINT-6798321:Ubiquitin (uniprotkb:P62988) physically interacts (MI:0218) with NFATc4 (uniprotkb:Q14934) by pull down (MI:0096

An animal model of SARS produced by infection of Macaca mulatta with SARS coronavirus.

A new SARS animal model was established by inoculating SARS coronavirus (SARS-CoV) into rhesus macaques (Macaca mulatta) through the nasal cavity. Pathological pulmonary changes were successively detected on days 5-60 after virus inoculation. All eight animals showed a transient fever 2-3 days after inoculation. Immunological, molecular biological, and pathological studies support the establishment of this SARS animal model. Firstly, SARS-CoV-specific IgGs were detected in the sera of macaques from 11 to 60 days after inoculation. Secondly, SARS-CoV RNA could be detected in pharyngeal swab samples using nested RT-PCR in all infected animals from 5 days after virus inoculation. Finally, histopathological changes of interstitial pneumonia were found in the lungs during the 60 days after viral inoculation: these changes were less marked at later time points, indicating that an active healing process together with resolution of an acute inflammatory response was taking place in these animals. This animal model should provide insight into the mechanisms of SARS-CoV-related pulmonary disease and greatly facilitate the development of vaccines and therapeutics against SARS

Responses of soil microbial communities to a short-term application of seaweed fertilizer revealed by deep amplicon sequencing

Numerous studies have reported soil damage from chemical fertilizer application and an obvious promotional effect of seaweed fertilizer fermented with Sargassum horneri on the growth of tomato roots and seedlings due to its alginate oligosaccharide. However, few studies have assessed the effects of the fermented seaweed fertilizer on ecological environment and microorganisms in soil. Herein, our objective is to uncover microbial and soil environmental responses to Sargassum horneri-fermented seaweed fertilizer. After treated tomato-planting plots with Sargassum horneri fermented seaweed fertilizer, soil bacterial community compositions based on 16S rRNA gene amplicon sequencing, enzyme activities in soil and crop yield were analyzed. The bacterial a-diversity was strongly influenced by seaweed fertilizer amendment after 60 days. Non-metric multidimensional scaling (NMDS) analysis showed that a difference in bacterial community compositions between day 0 and day 60 was obvious for soil treated with seaweed fertilizer. The community variation could be caused by invertase activity and dehydrogenase activity in canonical correlation analysis (CCA). Protease activity, polyphenol oxidase activity and urease activity showed an obvious correlation with community variation in the Mantel test. The fertilization increased tomato yield by 1.48-1.83 times, Vc content by 1.24-4.55 times and lycopene content by 1.20-2.33 times. In the present study, a possible reason for bacterial community variation was discovered, which will provide an economical dilution rate of seaweed fertilizer for optimal crop yield and quality. Meanwhile, our study will be beneficial for developing a possible substitute for chemical fertilizer and an improved understanding of soil microbial functions and soil sustainability

PDE2 Inhibits PKA-Mediated Phosphorylation of TFAM to Promote Mitochondrial Ca2+-Induced Colorectal Cancer Growth

Growing evidence indicates that the dysregulation of mitochondrial calcium (Ca2+) plays a critical role in the growth of tumor cells, including colorectal cancer (CRC). However, the underling mechanism is not fully elucidated. In this study, the regulatory effects of mitochondrial Ca2+ on phosphodiesterase 2 (PDE2)/cAMP/PKA axis and the phosphorylation of mitochondrial transcription factor A (TFAM) as well as the growth of CRC cells were systematically investigated both in vitro and in vivo. Our findings demonstrated that MCU-induced mitochondrial Ca2+ uptake activated mitochondrial PDE2 in CRC cells. Moreover, overexpression MCU in CRC led to a 1.9-fold increase in Ca2+ uptake compared to control cells. However, knockdown of MCU resulted in 1.5-fould decrease in Ca2+ uptake in mitochondria compared to the controls. Activation of mitochondrial PDE2 significantly inhibited the activity of mitochondrial protein kinase A (PKA), which subsequently leads to decreased phosphorylation of TFAM. Our data further revealed that PKA regulates the phosphorylation of TFAM and promotes the degradation of phosphorylated TFAM. Thus, TFAM protein levels accumulated in mitochondria when the activity of PKA was inhibited. Overall, this study showed that the overexpression of MCU enhanced CRC growth through promoting the accumulation of TFAM proteins in mitochondria. Conversely, knockdown of MCU in CRC cells resulted in decreased CRC growth. Collectively, these data suggest that the mitochondrial Ca2+-activated PDE2/cAMP/PKA axis plays a key role in regulating TFAM stability and the growth of CRC cells

Combining First-Principles Density Functional Theory Calculations with Experimental Approaches to Understand the Impacts of Doping on the Electrical Conductivities of Hematite

Hematite is a promising material for many different energy conversion and storage applications due to advantages such as low cost, high abundance, and good chemical stability. However, the low electrical conductivity of hematite has hindered the wide application of hematite in for different applications. Atomic doping is one of the most used approaches to tackle the electrical conductivity problem in hematite. Although many works have been done to understand the effects of atomic doping to the electrical conductivity of hematite, there are still many questions not answered yet. In this dissertation, we couple first-principles density functional theory (DFT) calculations with experimental approaches to dive deep into the system and answer unsolved questions in the community by taking advantages of both approaches. We, first of all, employ first-principles DFT calculations to predict how atomic doping impacts the carrier concentrations, carrier mobility and electrical conductivity of hematite. Then we conduct experiments to verify previous predicted results starting from materials synthesis, then materials characterizations, and, in the end, performance measurement. This series of works deepen people’s understanding about how atomic doping impacts the electrical conductivities of hematite and provide a possible validated collaboration mode between first-principles DFT calculations and experimental approaches

AITurk: Using ChatGPT for Social Science Research

Artificial intelligence, especially large language models (LLMs), has been widely used for scientific research. Yet, few studies have explored their potential to advance social science research. This research evaluates how effectively ChatGPT can mimic responses from real human participants on online crowdsourcing platforms such as Amazon Mechanical Turk (MTurk), Prolific, and CloudResearch. We replicated 22 studies published in top psychology journals between January 2023 and June 2023. Since ChatGPT 4.0’s cutoff date is September 2021, its training database does not include articles published after that time. The current research is among the first to use ChatGPT to replicate social science studies whose conclusions have not been included in the training database of ChatGPT. This unique methodology strengthens the credibility of our findings and establishes a more robust foundation for applying AI in simulating human behavior. The results show that ChatGPT successfully replicates about 93.2% (20.5/22) of the findings from these studies. While conducting these studies (assuming each study is a typical 5-minute online experiment with 300 participants) on online crowdsourcing platforms could take approximately 11 days and cost around $3,960, using AI through a platform we term “AITurk” could reduce the time to about 11 minutes and the cost to$132. That is, AITurk achieves about 93.2% accuracy of real human participants’ responses on online crowdsourcing platforms, with about 1/1440 time and 1/30 cost. Based on these findings, we suggest that ChatGPT can be an effective tool for social science research, especially for conducting preliminary research and evaluating the replicability of existing studies