Syntheses and characterizations of the in vivo replicative bypass and mutagenic properties of the minor-groove O2-alkylthymidine lesions.

Endogenous metabolism, environmental exposure, and treatment with some chemotherapeutic agents can all give rise to DNA alkylation, which can occur on the phosphate backbone as well as the ring nitrogen or exocyclic nitrogen and oxygen atoms of nucleobases. Previous studies showed that the minor-groove O(2)-alkylated thymidine (O(2)-alkyldT) lesions are poorly repaired and persist in mammalian tissues. In the present study, we synthesized oligodeoxyribonucleotides harboring seven O(2)-alkyldT lesions, with the alkyl group being a Me, Et, nPr, iPr, nBu, iBu or sBu, at a defined site and examined the impact of these lesions on DNA replication in Escherichia coli cells. Our results demonstrated that the replication bypass efficiencies of the O(2)-alkyldT lesions decreased with the chain length of the alkyl group, and these lesions directed promiscuous nucleotide misincorporation in E. coli cells. We also found that deficiency in Pol V, but not Pol II or Pol IV, led to a marked drop in bypass efficiencies for most O(2)-alkyldT lesions. We further showed that both Pol IV and Pol V were essential for the misincorporation of dCMP opposite these minor-groove DNA lesions, whereas only Pol V was indispensable for the T→A transversion introduced by these lesions. Depletion of Pol II, however, did not lead to any detectable alterations in mutation frequencies for any of the O(2)-alkyldT lesions. Thus, our study provided important new knowledge about the cytotoxic and mutagenic properties of the O(2)-alkyldT lesions and revealed the roles of the SOS-induced DNA polymerases in bypassing these lesions in E. coli cells

Multi-Image Semantic Matching by Mining Consistent Features

This work proposes a multi-image matching method to estimate semantic correspondences across multiple images. In contrast to the previous methods that optimize all pairwise correspondences, the proposed method identifies and matches only a sparse set of reliable features in the image collection. In this way, the proposed method is able to prune nonrepeatable features and also highly scalable to handle thousands of images. We additionally propose a low-rank constraint to ensure the geometric consistency of feature correspondences over the whole image collection. Besides the competitive performance on multi-graph matching and semantic flow benchmarks, we also demonstrate the applicability of the proposed method for reconstructing object-class models and discovering object-class landmarks from images without using any annotation.Comment: CVPR 201

NATURAL LANGUAGE PROCESSING BASED GENERATOR OF TESTING INSTRUMENTS

Natural Language Processing (NLP) is the field of study that focuses on the interactions between human language and computers. By “natural language” we mean a language that is used for everyday communication by humans. Different from programming languages, natural languages are hard to be defined with accurate rules. NLP is developing rapidly and it has been widely used in different industries. Technologies based on NLP are becoming increasingly widespread, for example, Siri or Alexa are intelligent personal assistants using NLP build in an algorithm to communicate with people. “Natural Language Processing Based Generator of Testing Instruments” is a stand-alone program that generates “plausible” multiple-choice selections by analyzing word sense disambiguation and calculating semantic similarity between two natural language entities. The core is Word Sense Disambiguation (WSD), WSD is identifying which sense of a word is used in a sentence when the word has multiple meanings. WSD is considered as an AI-hard problem. The project presents several algorithms to resolve WSD problem and compute semantic similarity, along with experimental results demonstrating their effectiveness

CHINESE LANGUAGE LEARNER'S MOTIVATION, INTENDED EFFORT, AND CONTINUATION OF STUDY

Motivation has been widely recognized as one of the key factors in second language (L2) learning and teaching. Yet very few motivational studies have examined adolescents’ motivation to learn a specific L2 within the framework of the contemporary expectancy-value theory, even less empirical research has been done in the Chinese as a Second Language (CSL) setting. It is unclear whether there are differences between boys’ and girls’ perceptions of expectancies for success, task values, and task difficulty in CSL learning. Furthermore, while most research associates motivation with language proficiency, a limited number of CSL studies have addressed the relations between motivation and motivational behaviors such as intended effort and continuation of study. One important purpose of the present study is to apply expectancy-value theory to develop a reliable and valid CSL Learning Motivation Scale which assesses adolescents’ motivation. Based on the literature review, the results of item examination, and expert feedback, a 34-item CSL Learning Motivation Scale was constructed. I conducted a Principal Component Analysis (PCA) to examine the factor structures of the final 34 items based on responses from the 219 students in Grade 6-12 at secondary schools in Southwestern United States. The results yielded five factors: ability/expectancy-related beliefs, intrinsic value-linguistic interests, intrinsic value-cultural interests, utility/attainment value, and perceived task difficulty. The final 34-item CSL Learning Motivation Scale displayed high internal consistency (α=.92). The reliabilities of the above five factors were .87, .80, .84, .92, and .86, respectively. Furthermore, this study examined if adolescents’ expectancy-value motivation in CSL learning significantly predicted their motivational behaviors. The results of regression analysis demonstrated that expectancy-value constructs explained 64% of the variance in intended effort and 74% of the variance in continuation of study. Specifically, expectancy/ability beliefs, intrinsic value-linguistic interests, utility/attainment value, and task difficulty perceptions significantly predicted students’ intended efforts. Expectancy/ability beliefs, intrinsic value-linguistic interests, and utility/attainment value significantly predicted continuation of study. In addition, this study attempted to explore gender differences in expectancy-value motivation in the CSL setting. MANOVA analyses revealed that gender differences in these motivational constructs were not significant.Psychological, Health, and Learning Sciences, Department o

Analog hardware security and hardware authentication

Hardware security and hardware authentication have become more and more important concerns in the manufacture of trusted integrated circuits. In this dissertation, a detailed study of hardware Trojans in analog circuits characterized by the presence of extra operating points or modes is presented. In a related study, a counterfeit countermeasure method based upon PUF authentication circuits is proposed for addressing the growing proliferation of counterfeit integrated circuits in the supply chain. Most concerns about hardware Trojans in semiconductor devices are based upon an implicit assumption that attackers will focus on embedding Trojans in digital hardware by making malicious modifications to the Boolean operation of a circuit. In stark contrast, hardware Trojans can be easily embedded in some of the most basic analog circuits. In this work, a particularly insidious class of analog hardware Trojans that require no architectural modifications, no area or power overhead, and prior to triggering, that leave no signatures in any power domains or delay paths is introduced. The Power/Architecture/Area/Signature Transparent (PAAST) characteristics help the Trojan “hide” and make them very difficult to detect with existing hardware Trojan detection methods. Cleverly hidden PAAST Trojans are nearly impossible to detect with the best simulation and verification tools, even if a full and accurate disclosure of the circuit schematic and layout is available. Aside from the work of the author of this dissertation and her classmates, the literature is void of discussions of PAAST analog hardware Trojans. In this work, examples of circuits showing the existence of PAAST analog hardware Trojans are given, the PAAST characteristics of these types of hardware Trojans are discussed, and heuristic detection methods that can help to detect these analog hardware Trojans are proposed. Another major and growing problem in the modern IC supply chain is the proliferation of counterfeit chips that are often characterized by different or inferior performance characteristics and reduced reliability when compared with authentic parts. A counterfeit countermeasure method is proposed that should lower the entry barrier for major suppliers of commercial off the shelf (COTS) parts to offer authenticated components to the military and other customers that have high component reliability requirements. The countermeasure is based upon a PUF authentication circuit that requires no area, pin, or power overhead, and causes no degradation of performance of existing and future COTS components

Eeg experimental study on the infl uence of learning activity design on learning effect

With the rapid development of new media, online learning has become an indispensable form of educational practice all over the world. A large number of studies and practices have shown that the gamifi cation of online learning has improved students’ engagement and attention to a certain extent, but there are still some problems in some aspects. This study intends to use EEG interaction technology to monitor students’ learning situation in real time, and study the infl uence of diff erent learning activity designs on students’ learning effi ciency and continuous learning willingness through the design of diff erent elements of learning activities, such as learning knowledge density design and knowledge quantity design. To further understand the learning effi ciency and continuous learning willingness of students when they participate in diff erent learning activities, propose and verify the relationships and principles between diff erent parameters, and provide scientifi c methods and theoretical basis for the design of gamifi ed education system

5,8-Dibromo-14,15,17,18-tetra­methyl-2,11-dithia­[3.3]paracyclo­phane

In the title mol­ecule [systematic name: 12,15-dibromo-52,53,55,56-tetramethyl-3,7-dithia-1,5(1,4)-dibenzenacyclooctaphane], C20H22Br2S2, the distance between the centroids of the two benzene rings is 3.326 (4) Å, and their mean planes are almost parallel, forming a dihedral angle of 1.05 (7)°. The crystal packing exhibits no inter­molecular contacts shorter than the sum of van der Waals radii