PrObeD: Proactive Object Detection Wrapper

Previous research in $2D$ object detection focuses on various tasks, including detecting objects in generic and camouflaged images. These works are regarded as passive works for object detection as they take the input image as is. However, convergence to global minima is not guaranteed to be optimal in neural networks; therefore, we argue that the trained weights in the object detector are not optimal. To rectify this problem, we propose a wrapper based on proactive schemes, PrObeD, which enhances the performance of these object detectors by learning a signal. PrObeD consists of an encoder-decoder architecture, where the encoder network generates an image-dependent signal termed templates to encrypt the input images, and the decoder recovers this template from the encrypted images. We propose that learning the optimum template results in an object detector with an improved detection performance. The template acts as a mask to the input images to highlight semantics useful for the object detector. Finetuning the object detector with these encrypted images enhances the detection performance for both generic and camouflaged. Our experiments on MS-COCO, CAMO, COD$10$K, and NC$4$K datasets show improvement over different detectors after applying PrObeD. Our models/codes are available at https://github.com/vishal3477/Proactive-Object-Detection.Comment: Accepted at Neurips 202

Chemical constituents, and pharmacological and toxicological effects of Cynomorium songaricum: An overview

Purpose: To review the chemical constituents, and the pharmacological and toxicological effects of Cynomorium songaricum (C. songaricum) and explore its potentials for further development as an alternative medicine.Methods: A large number of research articles related to “Cynomorium songaricum” “pharmacological effects”, “toxicological effects” and “chemical composition” in English and Chinese language were retrieved through an extensive literature review using various electronic databases including Medline(1966 - 2017) and EMBASE (1980 - 2017).Results: Ethyl acetate and aqueous extracts of C. songaricum have promising pharmacological activities, due to the presence of various flavonoids, triterpenes and polysaccharides. In addition to promising effects against inflammation, aging, fatigue, viruses and cancer,/ihas a protective effect on the nervous system and regulates hormones and immune functions. Oxidative regulation of hormone levels has a certain correlation with its pharmacological activities, e.g., cognitive functions, but its mechanism is not yet known, indicating the need for further research. Toxicity studies on C. songaricum have shown that it is not genotoxic to animals, but further toxicological studies are required to ascertain its safety in clinical use.Conclusion: C. songaricum is a biologically important plant which has many proven bioactivities; however, it requires further studies to determine the mechanistic aspects of its pharmacological effects.Keywords: Cynomorium, Chemical constituents, Inflammation, Aging, Fatigue, Virus, Tumor, Toxicological effec

Understanding the Li-ion storage mechanism in a carbon composited zinc sulfide electrode

Sulfide compounds are interesting conversion electrode materials for Li-ion batteries, due to their high theoretical capacity. However, they suffer from large volumetric changes and fast capacity fading. To overcome these issues, nanosized zinc sulfide (ZnS) modified with polyelectrolytes and graphene (ZnS-C/G) has been synthesized and investigated as an enhanced conversion-alloying anode material. In situ synchrotron X-ray diffraction and X-ray absorption spectroscopy are used to elucidate the Li storage process during the 1st cycle. In addition, the evolution of internal resistance and the corresponding solid electrolyte interphase (SEI) formation during the 1st cycle are discussed based on electrochemical impedance spectroscopy and X-ray photoelectron spectroscopy. The results reveal that the formation of lithiated products and the SEI layer at different voltages can influence Li+ diffusion into the electrode. Moreover, an artificial carbon layer can not only facilitate Li+ transport but also avoid the direct formation of the SEI layer on the surface of active particles. Compared to bare ZnS, the ZnS-C/G electrode shows outstanding rate capability and cycling capacity (571 mA h g−1 after 120 cycles at a specific current of 1.0 A g−1 with a retention rate of 94.4%). The high capacity at elevated current density is ascribed to the contribution of capacitive charge storage

Improved Tensile Ductility by Severe Plastic Deformation for Nano-Structured Metallic Glass

The effect of severe plastic deformation by high-pressure torsion (HPT) on the structure and plastic tensile properties of two Zr-based bulk metallic glasses, Zr55.7Ni10Al7Cu19Co8.3 and Zr64Ni10Al7Cu19, was investigated. The compositions were chosen because, in TEM investigation, Zr55.7Ni10Al7Cu19Co8.3 exhibited nanoscale inhomogeneity, while Zr64Ni10Al7Cu19 appeared homogeneous on that length scale. The nanoscale inhomogeneity was expected to result in an increased plastic strain limit, as compared to the homogeneous material, which may be further increased by severe mechanical work. The as-cast materials exhibited 0.1% tensile plasticity for Zr64Ni10Al7Cu19 and Zr55.7Ni10Al7Cu19Co8.3. Following two rotations of HPT treatment, the tensile plastic strain was increased to 0.5% and 0.9%, respectively. Further testing was performed by X-ray diffraction and by differential scanning calorimetry. Following two rotations of HPT treatment, the initially fully amorphous Zr55.7Ni10Al7Cu19Co8.3 exhibited significantly increased free volume and a small volume fraction of nanocrystallites. A further increase in HPT rotation number did not result in an increase in plastic ductility of both alloys. Possible reasons for the different mechanical behavior of nanoscale heterogeneous Zr55.7Ni10Al7Cu19Co8.3 and homogeneous Zr64Ni10Al7Cu19 are presented

The Structural Basis of Gas-Responsive Transcription by the Human Nuclear Hormone Receptor REV-ERBβ

Heme is a ligand for the human nuclear receptors (NR) REV-ERBα and REV-ERBβ, which are transcriptional repressors that play important roles in circadian rhythm, lipid and glucose metabolism, and diseases such as diabetes, atherosclerosis, inflammation, and cancer. Here we show that transcription repression mediated by heme-bound REV-ERBs is reversed by the addition of nitric oxide (NO), and that the heme and NO effects are mediated by the C-terminal ligand-binding domain (LBD). A 1.9 Å crystal structure of the REV-ERBβ LBD, in complex with the oxidized Fe(III) form of heme, shows that heme binds in a prototypical NR ligand-binding pocket, where the heme iron is coordinately bound by histidine 568 and cysteine 384. Under reducing conditions, spectroscopic studies of the heme-REV-ERBβ complex reveal that the Fe(II) form of the LBD transitions between penta-coordinated and hexa-coordinated structural states, neither of which possess the Cys384 bond observed in the oxidized state. In addition, the Fe(II) LBD is also able to bind either NO or CO, revealing a total of at least six structural states of the protein. The binding of known co-repressors is shown to be highly dependent upon these various liganded states. REV-ERBs are thus highly dynamic receptors that are responsive not only to heme, but also to redox and gas. Taken together, these findings suggest new mechanisms for the systemic coordination of molecular clocks and metabolism. They also raise the possibility for gas-based therapies for the many disorders associated with REV-ERB biological functions

Nano-electrospray mass spectrometry for the analysis of neurosteroids and related molecules

Neurosteroids are steroids synthesised in the central and peripheral nervous systems. Known neurosteroids include pregnenolone, dehydroepiandrosterone (DHEA), progesterone and its reduced metabolites. It has been demonstrated that neurosteroids modulate neurotransmission by binding to neurotransmitter receptors, and exert physiological functions that are clearly different from those of endocrine steroids. The effects of neurosteroids on improving the memory of cognitively impaired aged rats, on the inhibition of aggressiveness in castrated male mice, and trophic effects on neuronal regeneration and remyelination have been documented. The local synthesis, selective interaction with neurotransmitter receptors and behavioural effects of neurosteroids strongly suggests that they may have important physiological or pathophysiological roles. There is an increasing need to develop methods to analyse these hormones with high sensitivity and high specificity. In this thesis I focused on the development of methods combining nano-electrospray (ES) mass spectrometry with capillary column liquid chromatography (CLC) for the analysis of profiles of neurosteroids in rat brain. It was also an aim to make the methods applicable to a broad range of lipophilic biomolecules. Initially, synthetic steroid sulphates and unconjugated oxosteroids (ketosteroids) were studied by nano-ES and tandem mass spectrometry. Steroid sulphates could be detected as deprotonated molecules in full range scanned spectra at a level of 1 pg/µL. Information about steroid structure was obtained from collision-induced dissociation (CID) spectra of 1 ng of steroid sulphate, while characterisation of the sulphate ester group required only 3 pg of material. Unconjugated oxosteroids were converted into their oximes which were detected as protonated molecules with 20 times higher sensitivity than the underivatised steroids. The detection limits for the oximes of 3-oxo-delta4, 20-oxo and 17-oxo steroids were 2.5, 5, and 25 pg/µL, respectively in full range scans. CID spectra of the protonated oximes provided valuable information regarding the position of oxo and hydroxyl group(s). These studies established a basis for determination and structure characterisation of neurosteroids from brain samples A procedure for CLC-ES mass spectrometry was then developed. A double splitter method was introduced which made it possible to use a pre-column for analyte focusing from large sample volumes. It also made it possible to operate the solvent pumps at flow rates compatible with gradient elution while the flow rates through the analytical column were compatible with micro-electrospray. The method was designed to be generally applicable to the analysis of biomolecules and its utilities were demonstrated by the analysis of steroid sulphates, in human plasma. In the course of these studies, certain CLC-ES conditions were found to cause on-column chemical transformations of 3beta- hydroxy-delta5 steroid sulphates. Radical species generated from electrolysis of water and methanol in the solvent are proposed to be responsible for the formation of oxidised and methoxylated products of these steroids. Other analytes with double bonds were also transformed under these conditions. Thus, on-column electrochemistry can be an important source of artefacts in analyses by CLC-ES mass spectrometry. The reactions could be prevented by appropriate grounding. The analysis of neurosteroids in rat brain required the development of an extraction, purification and subfractionation procedure. Brain steroids were extracted, and unconjugated neutral steroids and sulphated steroids were separated. The steroid sulphate fraction was then analysed by CLC-ES mass spectrometry. Endogenous sulphates of pregnenolone and DHEA were not detected at levels above the detection limit, 0.3 ng/g wet brain, while pregnenolone sulphate, added to brain extract at a level of 6.6 ng/g, was easily detected. The unconjugated oxosteroids were converted to their oximes, selectively isolated on a cation exchanger, and analysed by CLC-ES tandem mass spectrometry. The chromatograms showed the presence of progesterone, pregnenolone, pregnanolone isomers, DHEA and testosterone in rat brain. These steroids were characterised by tandem mass spectrometry, Based on the results of CLC-ES tandem mass spectrometry, the levels Of C21 and C19 steroids were estimated in the range of 0.04 - 20 ng/g wet brain. The levels of progesterone and testosterone showed a sex difference. During the development of the above analytical methods, nano-ES mass spectrometry was applied to the characterisation of a lipophilic modulatory factor isolated from mouse brain. The factor, which activated the retinoid X receptor (RXR), was extracted from mouse brain incubates, purified by HPLC and analysed by nano-ES and tandem mass spectrometry. Accurate mass measurement and CID spectra of the purified active compound revealed that it was cis-4,7,10,13,16,19docosahexaenoic acid. In conclusion, the methods developed and described in this thesis are suitable for the analysis of sulphated steroids and oxosteroids, as well as other related compounds. With their high sensitivity the methods enable highly specific analysis of these important compounds from small amounts of sample

A Bibliometric Analysis of Computer-assisted English Learning from 2001 to 2020

The aim of this study was to reveal hotspots and frontiers of computer-assisted English learning (CAEL) studies indexed by EI Compendex database from 2001 to 2020 via bibliometric analysis. The publication output has exponentially grown in the past two decades and is likely to progress in the next several years. China occupied the leading position， while Lecture Notes in Computer Science was the most prolific journal, and Deyi Xiong was the most productive author. Keyword analysis was assisted by VOSviewer software. Our results show that “computer aided instruction”, “computer aided language translation” and “learning systems” were the most frequently used keywords in documents. CAEL studies were mainly conducted from five dimensions (technology, learners, teaching, English acquisition and testing). The findings of this study have implications for English language instructors. Teaching methods and modes should be adjusted according to technology development