Mutation of Arabidopsis HY1 causes UV-C hypersensitivity by impairing carotenoid and flavonoid biosynthesis and the down-regulation of antioxidant defence

Previous pharmacological results confirmed that haem oxygenase-1 (HO-1) is involved in protection of cells against ultraviolet (UV)-induced oxidative damage in soybean [Glycine max (L.) Merr.] seedlings, but there remains a lack of genetic evidence. In this study, the link between Arabidopsis thaliana HO-1 (HY1) and UV-C tolerance was investigated at the genetic and molecular levels. The maximum inducible expression of HY1 in wild-type Arabidopsis was observed following UV-C irradiation. UV-C sensitivity was not observed in ho2, ho3, and ho4 single and double mutants. However, the HY1 mutant exhibited UV-C hypersensitivity, consistent with the observed decreases in chlorophyll content, and carotenoid and flavonoid metabolism, as well as the down-regulation of antioxidant defences, thereby resulting in severe oxidative damage. The addition of the carbon monoxide donor carbon monoxide-releasing molecule-2 (CORM-2), in particular, and bilirubin (BR), two catalytic by-products of HY1, partially rescued the UV-C hypersensitivity, and other responses appeared in the hy1 mutant. Transcription factors involved in the synthesis of flavonoid or UV responses were induced by UV-C, but reduced in the hy1 mutant. Overall, the findings showed that mutation of HY1 triggered UV-C hypersensitivity, by impairing carotenoid and flavonoid synthesis and antioxidant defences

Knockoff-Guided Feature Selection via A Single Pre-trained Reinforced Agent

Feature selection prepares the AI-readiness of data by eliminating redundant features. Prior research falls into two primary categories: i) Supervised Feature Selection, which identifies the optimal feature subset based on their relevance to the target variable; ii) Unsupervised Feature Selection, which reduces the feature space dimensionality by capturing the essential information within the feature set instead of using target variable. However, SFS approaches suffer from time-consuming processes and limited generalizability due to the dependence on the target variable and downstream ML tasks. UFS methods are constrained by the deducted feature space is latent and untraceable. To address these challenges, we introduce an innovative framework for feature selection, which is guided by knockoff features and optimized through reinforcement learning, to identify the optimal and effective feature subset. In detail, our method involves generating "knockoff" features that replicate the distribution and characteristics of the original features but are independent of the target variable. Each feature is then assigned a pseudo label based on its correlation with all the knockoff features, serving as a novel metric for feature evaluation. Our approach utilizes these pseudo labels to guide the feature selection process in 3 novel ways, optimized by a single reinforced agent: 1). A deep Q-network, pre-trained with the original features and their corresponding pseudo labels, is employed to improve the efficacy of the exploration process in feature selection. 2). We introduce unsupervised rewards to evaluate the feature subset quality based on the pseudo labels and the feature space reconstruction loss to reduce dependencies on the target variable. 3). A new {\epsilon}-greedy strategy is used, incorporating insights from the pseudo labels to make the feature selection process more effective

Robust, source-independent biases in children's use of socially and individually acquired information

Culture has an extraordinary influence on human behaviour, unparalleled in other species. Some theories propose that humans possess learning mechanisms biologically selected specifically for social learning, which function to promote rapid enculturation. If true, it follows that information acquired via observation of another's activity might be responded to differently, compared with equivalent information acquired through one's own exploration, and that this should be the case in even very young children. To investigate this, we compared children's responses to information acquired either socially, or from personal experience. The task we used allowed direct comparison between these alternative information sources, as the information value was equivalent across conditions, which has not been true of previous methods used to tackle similar questions. Across two 18mo-5yo samples (recruited in the UK and China) we found that children performed similarly following information acquired from social demonstrations, compared with personal experience. Children's use of the information thus appeared independent of source. Furthermore, children's suboptimal performance showed evidence of a consistent bias driven by motivation for exploration as well as exploitation, which was apparent across both conditions and in both samples. Our results are consistent with the view that apparent peculiarities identified in human social information use could be developmental outcomes of general-purpose learning and motivational biases, as opposed to mechanisms that have been biologically selected specifically for the acquisition of cultural information

Structure and Wear Properties of Nano-silicon dioxide modified Polyacrylate composites

Conference Name:2nd International Conference on Multi-Functional Materials and Structures. Conference Address: Qingdao, PEOPLES R CHINA. Time:OCT 09-12, 2009.polyacrylate/nano-silicon dioxide nanocomposites were fabricated through a simple mixing process for resisting scratch and wear as coating. Chemical compatibility between polyacrylate matrix and nano-silicon dioxide (nano-SiO(2)) was achieved by functionalized nano-SiO(2) via three silane coupling agents. Scanning electron microscopy (SEM) was done to characterize surface and wear morphology of the nanocomposites. Differential scanning calorimetry (DSC) was used for representing interfacial properties of the nanocomposites. A MM-200 machine and a Norman Tool RCA abrader were performed for testing friction and wear properties. SEM showed that incorporation of the nano-SiO(2) functionalized with silane into the polyacrylate matrix showed a better dispersion than the composite without silane at low nanoparticle content (<= 3 wt%). SEM also revealed that adhesive wear mechanism of the polyacrylate matrix was transited to dominated particle wear of the nanocomposites. An increase of glass transition temperature (T(g)) was recorded via DSC at low nanoparticle content (1 wt%). Further addition of the nanoparticles to 3 wt% led to a 10 C increase in T(g) comparing to neat polyacrylate. Results of friction and wear properties exhibited that friction coefficient and wear loss of the nanocomposites with silane were lower than those of the neat polyacrylate. The wear loss of the neat polyacrylate, the nanocomposite containing 3 wt% nanoparticles with silane KH570, and the nanocomposite with raw nano-particles were 108.6, 65.8, and 110.5mg, respectively. RCA results also showed a significant improvement of the nanocomposites in the presence of the nanoparticles with silane

Haem oxygenase delays programmed cell death in wheat aleurone layers by modulation of hydrogen peroxide metabolism

Haem oxygenase-1 (HO-1) confers protection against a variety of oxidant-induced cell and tissue injury in animals and plants. In this report, it is confirmed that programmed cell death (PCD) in wheat aleurone layers is stimulated by GA and prevented by ABA. Meanwhile, HO activity and HO-1 protein expression exhibited lower levels in GA-treated layers, whereas the hydrogen peroxide (H2O2) content was apparently increased. The pharmacology approach illustrated that scavenging or accumulating H2O2 either delayed or accelerated GA-induced PCD. Furthermore, pretreatment with the HO-1 specific inhibitor, zinc protoporphyrin IX (ZnPPIX), before exposure to GA, not only decreased HO activity but also accelerated GA-induced PCD significantly. The application of the HO-1 inducer, haematin, and the enzymatic reaction product of HO, carbon monoxide (CO) aqueous solution, both of which brought about a noticeable induction of HO expression, substantially prevented GA-induced PCD. These effects were reversed when ZnPPIX was added, suggesting that HO in vivo played a role in delaying PCD. Meanwhile, catalase (CAT) and ascorbate peroxidase (APX) activities or transcripts were enhanced by haematin, CO, or bilirubin (BR), the catalytic by-product of HO. This enhancement resulted in a decrease in H2O2 production and a delay in PCD. In addition, the antioxidants butylated hydroxytoluene (BHT), dithiothreitol (DTT), and ascorbic acid (AsA) were able not only to delay PCD but also to mimic the effects of haematin and CO on HO up-regulation. Overall, the above results suggested that up-regulation of HO expression delays PCD through the down-regulation of H2O2 production

Embracing the Market: Entry into Self-Employment in Transitional China, 1978-1996

This paper introduces labor market transition as an intervening process by which the macro institutional transition to a market economy alters social stratification outcome. Rather than directly addressing income distribution, it examines the pattern of workers’ entry into self-employment in reform-era China (1978-1996), focusing on rural-urban differences and the temporal trend. Analyses of data from a national representative survey in China show that education, party membership and cadre status all deter urban workers’ entry into self-employment, while education promotes rural workers’ entry into self-employment. As marketization proceeds, the rate of entry into self-employment increases in both rural and urban China, but urban workers are increasingly more likely to take advantages of the new market opportunities. In urban China, college graduates and cadres are still less likely to be involved in self-employment, but they are becoming more likely to do so in the later phase of reform. The diversity of transition scenarios is attributed to rural-urban differences in labor market structures.http://deepblue.lib.umich.edu/bitstream/2027.42/39897/3/wp512.pd

Study on pathological and clinical characteristics of chronic HBV infected patients with HBsAg positive, HBV DNA negative, HBeAg negative

AimsStudy of clinical characteristics of hepatitis B virus deoxyribonucleic acid (HBV DNA)-negative, hepatitis B surface antigen (HBsAg)-positive, hepatitis B e antigen (HBeAg)-negative patients based on liver histopathology.MethodsWe retrospectively enrolled patients with chronic HBV infection diagnosis at Beijing Ditan Hospital from May 2008 to November 2020. To study the differences between patients with significant hepatic histopathology and those without significant hepatic histopathology. And to study the independent factors of significant hepatic histopathology.Results85 HBV DNA-negative and HBeAg-negative patients were 37.90 ± 10.30 years old, 23.50% of patients with grade of inflammation (G) &gt;1, 35.30% of patients with liver fibrosis stage (S) &gt;1, 44.70% patients were diagnosed with significant hepatic histopathology. Compared to the no significant hepatic histopathology group, another group had older age (41.70 ± 10.70 vs 34.80 ± 8.87 years, t=-3.28, P=0.002), higher total bilirubin (TBIL) [14.9(10.3, 22.4) vs 11(8.9, 14.4) μmol/L, z=-2.26, P=0.024], lower cholinesterase (CHE) (t=-2.86, P=0.005, 7388.00 ± 2156.00 vs 8988.00 ± 2823.00 U/L) and lower platelet (PLT) (t=2.75, P=0.007, 157.00 ± 61.40 vs 194.00 ± 61.00 10^9/L). Abnormal ALT patients are more likely to have significant hepatic histopathology (z=5.44, P=0.020, 66.70% vs 337.50%). G had significant correlation with CHE (P=0.008, r=-0.23), alanine aminotransferase (ALT) (P=0.041, r=0.18), aspartate aminotransferase (AST) (P=0.001, r=0.29). S had significant correlation with TBIL (P = 0.008, r = 0.23), age (P &lt; 0.001, r = 0.32), international normalized ratio (INR) (P = 0.04, r = 0.23), CHE (P &lt; 0.001, r = -0.30), PLT (P &lt; 0.001, r = -0.40) and prothrombin time activity (PTA) (P = 0.046, r = -0.22). Multivariate logistic analysis indicated only age (95%CI=1.014~1.130, OR=1.069, P=0.013) was an impact factor for significant hepatic histopathology. The cutoff point of age was 34.30 years.ConclusionsA large proportion of chronic HBV infection patients with HBeAg-negative and HBV DNA-negative still have chronic hepatitis. Age is an independent factor for significant hepatic histopatholog