New Detections of Optical Emission from Kiloparsec-scale Quasar Jets

We report initial results from the detection of optical emission in the arcsecond-scale radio jets of two quasars utilizing images from the {\it Hubble Space Telescope} archive. The optical emission has a very knotty appearance and is consistent with synchrotron emission from highly relativistic electrons in the jet. Combining these observations with those of previously reported features in other quasars, an emerging trend appears to be that their radio-to-optical spectral indices are steeper than those of similar features in jets of lower power radio sources.Comment: 4 pgs, 2 figs, Proc of The Physics of Relativistic Jets in the Chandra and XMM Era workshop, eds. G. Brunetti, D.E. Harris, R.M. Sambruna, and G. Setti, submitted to New Astronomy Review. Quality of figure 1 degraded to fit into preprint server. Includes elsart.cls fil

Antagonist Effect of Triptolide on AKT Activation by Truncated Retinoid X Receptor-alpha

Background: Retinoid X receptor-alpha (RXR alpha) is a key member of the nuclear receptor superfamily. We recently demonstrated that proteolytic cleavage of RXR alpha resulted in production of a truncated product, tRXR alpha, which promotes cancer cell survival by activating phosphatidylinositol-3-OH kinase (PI3K)/AKT pathway. However, how the tRXR alpha-mediated signaling pathway in cancer cells is regulated remains elusive. Methodology/Principal Findings: We screened a natural product library for tRXR alpha targeting leads and identified that triptolide, an active component isolated from traditional Chinese herb Trypterygium wilfordii Hook F, could modulate tRXR alpha-mediated cancer cell survival pathway in vitro and in animals. Our results reveal that triptolide strongly induces cancer cell apoptosis dependent on intracellular tRXR alpha expression levels, demonstrating that tRXR alpha serves as an important intracellular target of triptolide. We show that triptolide selectively induces tRXR alpha degradation and inhibits tRXR alpha-dependent AKT activity without affecting the full-length RXR alpha. Interestingly, such effects of triptolide are due to its activation of p38. Although triptolide also activates Erk1/2 and MAPK pathways, the effects of triptolide on tRXR alpha degradation and AKT activity are only reversed by p38 siRNA and p38 inhibitor. In addition, the p38 inhibitor potently inhibits tRXR alpha interaction with p85 alpha leading to AKT inactivation. Our results demonstrate an interesting novel signaling interplay between p38 and AKT through tRXR alpha mediation. We finally show that targeting tRXR alpha by triptolide strongly activates TNF alpha death signaling and enhances the anticancer activity of other chemotherapies Conclusions/Significance: Our results identify triptolide as a new xenobiotic regulator of the tRXR alpha-dependent survival pathway and provide new insight into the mechanism by which triptolide acts to induce apoptosis of cancer cells. Triptolide represents one of the most promising therapeutic leads of natural products of traditional Chinese medicine with unfortunate side-effects. Our findings will offer new strategies to develop improved triptolide analogs for cancer therapy.National Natural Science Foundation of China [NSFC: 30971445, 90913015, 91129302]; NSFC/Hong Kong Research Grants Council [NSFC/RGC: 30931160431/N_HKU 735/09]; Natural Science Foundation of Fujian Province [2009J01198

BnMs3 is required for tapetal differentiation and degradation, microspore separation, and pollen-wall biosynthesis in Brassica napus

7365AB, a recessive genetic male sterility system, is controlled by BnMs3 in Brassica napus, which encodes a Tic40 protein required for tapetum development. However, the role of BnMs3 in rapeseed anther development is still largely unclear. In this research, cytological analysis revealed that anther development of a Bnms3 mutant has defects in the transition of the tapetum to the secretory type, callose degradation, and pollen-wall formation. A total of 76 down-regulated unigenes in the Bnms3 mutant, several of which are associated with tapetum development, callose degeneration, and pollen development, were isolated by suppression subtractive hybridization combined with a macroarray analysis. Reverse genetics was applied by means of Arabidopsis insertional mutant lines to characterize the function of these unigenes and revealed that MSR02 is only required for transport of sporopollenin precursors through the plasma membrane of the tapetum. The real-time PCR data have further verified that BnMs3 plays a primary role in tapetal differentiation by affecting the expression of a few key transcription factors, participates in tapetal degradation by modulating the expression of cysteine protease genes, and influences microspore separation by manipulating the expression of BnA6 and BnMSR66 related to callose degradation and of BnQRT1 and BnQRT3 required for the primary cell-wall degradation of the pollen mother cell. Moreover, BnMs3 takes part in pollen-wall formation by affecting the expression of a series of genes involved in biosynthesis and transport of sporopollenin precursors. All of the above results suggest that BnMs3 participates in tapetum development, microspore release, and pollen-wall formation in B. napus

Withaferin A Exerts Preventive Effect on Liver Fibrosis through Oxidative Stress Inhibition in a Sirtuin 3-Dependent Manner

Sirtuin 3 (SIRT3) is a deacetylase involved in the development of many inflammation-related diseases including liver fibrosis. Withaferin A (WFA) is a bioactive constituent derived from the Withania somnifera plant, which has extensive pharmacological activities; however, little is known about the regulatory role of SIRT3 in the WFA-induced antifibrogenic effect. The current study is aimed at investigating the role of SIRT3 in WFA-induced antioxidant effects in liver fibrosis. Our study verified that WFA attenuated platelet-derived growth factor BB- (PDGF-BB-) induced liver fibrosis and promoted PDGF-BB-induced SIRT3 activity and expression in JS1 cells. SIRT3 silencing attenuated the antifibrogenic and antioxidant effects of WFA in activated JS1 cells. Moreover, WFA inhibited carbon tetrachloride- (CCl4-) induced liver injury, collagen deposition, and fibrosis; increased the SIRT3 expression; and suppressed the CCl4-induced oxidative stress in fibrotic livers of C57/BL6 mice. Furthermore, the antifibrogenic and antioxidant effects of WFA could be available in CCl4-induced WT (129S1/SvImJ) mice but were unavailable in CCl4-induced SIRT3 knockout (KO) mice. Our study suggested that WFA inhibited liver fibrosis through the inhibition of oxidative stress in a SIRT3-dependent manner. WFA could be a potential compound for the treatment of liver fibrosis

Unsupervised Learning for Enhanced Computed Photoacoustic Microscopy

Photoacoustic microscopy (PAM) is a medical-imaging technique with the merits of high contrast and resolution. Nevertheless, conventional PAM scans specimens in a diameter-by-diameter fashion, resulting in a time-consuming process. Furthermore, deep-learning-based PAM image enhancement necessitates acquiring ground-truth data for training purposes. In this paper, we built an optical-resolution photoacoustic microscopy system and introduced an innovative unsupervised-learning algorithm. First, we enhanced the rotational-scanning method, transitioning from a diameter-by-diameter approach to a sector-by-sector one, significantly reducing imaging time (from 280 s to 109 s). Second, by establishing a metric for unsupervised learning, we eliminated the need for collecting reliable and high-quality ground truth, which is a challenging task in photoacoustic microscopy. A total of 324 pairs of datasets (mouse ears) were collected for unsupervised learning, with 274 for training and 50 for testing. Additionally, carbon-fiber data were sampled for lateral resolution and contrast evaluation, as well as the effective rate evaluation of the algorithm. The enhanced images demonstrated superior performance compared with that of maximum projection, both subjectively and objectively. A 76% improvement in the lateral resolution was observed. The effective rate of the algorithm was measured to be 100%, which was tested on 50 random samples. The technique presented in this paper holds substantial potential for image postprocessing and opens new avenues for unsupervised learning in photoacoustic microscopy

An Automatic Identification Method of Crested Ibis (<i>Nipponia nippon</i>) Habitat Based on Spatiotemporal Density Detection

To address the current challenges of the heavy workload, time-consuming nature and labor-intensiveness involved in existing crested ibis’s (Nipponia nipponTemminck, 1835) habitat identification approaches, this paper proposes an automatic habitat identification method based on spatiotemporal density detection. With consideration of the characteristics of the crested ibis’s trajectory data, such as aggregation, repeatability, and uncertainty, this method achieves detecting the crested ibis’s stopping points by using the spatial characteristics of the trajectory data. On this basis, an improved spatiotemporal clustering-based DBSCAN method is proposed in this paper, incorporating temporal characteristics of the trajectory data. By combining the spatial and temporal features, the proposed method is able to accurately identify the roosting and foraging sites among the crested ibis’s stopping points. Supported by remote sensing images and field investigations, it was found that the method proposed in this paper has a good clustering effect and can effectively identify the crested ibis’s foraging sites and overnight roosting areas. Specifically, the woodland, farmland, and river areas are the common foraging sites for the crested ibis, while the woodland with large trees is their common overnight site. Therefore, the method proposed in this paper can provide technical support for identifying and protecting the crested ibis’s habitats

Adaptive Motion Skill Learning of Quadruped Robot on Slopes Based on Augmented Random Search Algorithm

To deal with the problem of stable walking of quadruped robots on slopes, a gait planning algorithm framework for quadruped robots facing unknown slopes is proposed. We estimated the terrain slope by the attitude information measured by the inertial measurement unit (IMU) without relying on the robot vision. The crawl gait was adopted, and the center of gravity trajectory planning was carried out based on the stability criterion zero-moment point (ZMP). Then, the augmented random search (ARS) algorithm was used to modulate the parameters of the Bezier curve to realize the planning of the robot foot trajectory. Additionally, the robot can adjust the posture in real time to follow the desired joint angle, which realizes the adaptive adjustment of the robot’s posture during the slope movement. Simulation experiment results show that the proposed algorithm for slope gait planning can adaptively adjust the robot’s attitude and stably pass through the slope environment when the slope is unknown

hNOA1 interacts with complex I and DAP3 and regulates mitochondrial respiration and apoptosis.

Mitochondria are dynamic organelles that play key roles in metabolism, energy production, and apoptosis. Coordination of these processes is essential to maintain normal cellular functions. Here we characterized hNOA1, the human homologue of AtNOA1 (Arabidopsis thaliana nitric oxide-associated protein 1), a large mitochondrial GTPase. By immunofluorescence, immunoelectron microscopy, and mitochondrial subfractionation, endogenous hNOA1 is localized within mitochondria where it is peripherally associated with the inner mitochondrial membrane facing the mitochondrial matrix. Overexpression and knockdown of hNOA1 led to changes in mitochondrial shape implying effects on mitochondrial dynamics. To identify the interaction partners of hNOA1 and to further understand its cellular functions, we performed immunoprecipitation-mass spectrometry analysis of endogenous hNOA1 from enriched mitochondrial fractions and found that hNOA1 interacts with both Complex I of the electron transport chain and DAP3 (death-associated protein 3), a positive regulator of apoptosis. Knockdown of hNOA1 reduces mitochondrial O(2) consumption approximately 20% in a Complex I-dependent manner, supporting a functional link between hNOA1 and Complex I. Moreover, knockdown of hNOA1 renders cells more resistant to apoptotic stimuli such as gamma-interferon and staurosporine, supporting a role for hNOA1 in regulating apoptosis. Thus, based on its interactions with both Complex I and DAP3, hNOA1 may play a role in mitochondrial respiration and apoptosis