Structural roles of CTG repeats in slippage expansion during DNA replication

CTG triplet repeat sequences have been found to form slipped-strand structures leading to self-expansion during DNA replication. The lengthening of these repeats causes the onset of neurodegenerative diseases, such as myotonic dystrophy. In this study, electrophoretic and NMR spectroscopic studies have been carried out to investigate the length and the structural roles of CTG repeats in affecting the hairpin formation propensity. Direct NMR evidence has been successfully obtained the first time to support the presence of three types of hairpin structures in sequences containing 1–10 CTG repeats. The first type contains no intra-loop hydrogen bond and occurs when the number of repeats is less than four. The second type has a 4 nt TGCT-loop and occurs in sequences with even number of repeats. The third type contains a 3 nt CTG-loop and occurs in sequences with odd number of repeats. Although stabilizing interactions have been identified between CTG repeats in both the second and third types of hairpins, the structural differences observed account for the higher hairpin formation propensity in sequences containing even number of CTG repeats. The results of this study confirm the hairpin loop structures and explain how slippage occurs during DNA replication

Boosting Few-Shot Semantic Segmentation Via Segment Anything Model

In semantic segmentation, accurate prediction masks are crucial for downstream tasks such as medical image analysis and image editing. Due to the lack of annotated data, few-shot semantic segmentation (FSS) performs poorly in predicting masks with precise contours. Recently, we have noticed that the large foundation model segment anything model (SAM) performs well in processing detailed features. Inspired by SAM, we propose FSS-SAM to boost FSS methods by addressing the issue of inaccurate contour. The FSS-SAM is training-free. It works as a post-processing tool for any FSS methods and can improve the accuracy of predicted masks. Specifically, we use predicted masks from FSS methods to generate prompts and then use SAM to predict new masks. To avoid predicting wrong masks with SAM, we propose a prediction result selection (PRS) algorithm. The algorithm can remarkably decrease wrong predictions. Experiment results on public datasets show that our method is superior to base FSS methods in both quantitative and qualitative aspects

Whiteboard Animations for Flipped Classrooms in a Common Core Science General Education Course

[EN] Whiteboard animation, an engaging tool for teaching and learning, consists of a series of hand-drawing illustrations with voice-over narration to explain complex and abstract ideas. Our team had produced four short whiteboard animations tailor-made for a common core science general education (GE) course. This study aims at evaluating the effectiveness of using these whiteboard animations for flipped classrooms in the common core science GE course. The pre-tutorial survey showed that students who watched the animations got significantly higher average marks in the quizzes at the beginning of the tutorials (p<0.001). The post-tutorial feedback survey indicated that the whiteboard animations attracted 67% of students to watch the animations. For students who watched the animations, over 86% of them reported that the animations raised their interest in the issues discussed in the tutorial classes, and learning materials in the form of whiteboard animation were more interesting than lecture videos; more than 90% of the students agreed the whiteboard animations were helpful in (i) understanding the assigned readings, (ii) clarifying the concepts of the discussed issues, and (iii) gaining the related knowledge before the tutorial. We concluded that whiteboard animation is an effective and engaging tool for flipped classrooms in the common core science GE course.We want to thank the Centre for eLearning and Innovation Technology of The Chinese University of Hong Kong for their support. This project was funded by the Micro-module Courseware Development Grant Scheme.Li, M.; Lai, CW.; Szeto, WM. (2019). Whiteboard Animations for Flipped Classrooms in a Common Core Science General Education Course. En HEAD'19. 5th International Conference on Higher Education Advances. Editorial Universitat Politècnica de València. 929-938. https://doi.org/10.4995/HEAD19.2019.9250OCS92993

Exogenous Expression of Human apoA-I Enhances Cardiac Differentiation of Pluripotent Stem Cells

The cardioprotective effects of high-density lipoprotein cholesterol (HDL-C) and apolipoprotein A1 (apoA-I) are well documented, but their effects in the direction of the cardiac differentiation of embryonic stem cells are unknown. We evaluated the effects of exogenous apoA-I expression on cardiac differentiation of ESCs and maturation of ESC-derived cardiomyocytes. We stably over-expressed full-length human apoA-I cDNA with lentivirus (LV)-mediated gene transfer in undifferentiated mouse ESCs and human induced pluripotent stem cells. Upon cardiac differentiation, we observed a significantly higher percentage of beating embryoid bodies, an increased number of cardiomyocytes as determined by flow cytometry, and expression of cardiac markers including α-myosin heavy chain, β-myosin heavy chain and myosin light chain 2 ventricular transcripts in LV-apoA-I transduced ESCs compared with control (LV-GFP). In the presence of noggin, a BMP4 antagonist, activation of BMP4-SMAD signaling cascade in apoA-I transduced ESCs completely abolished the apoA-I stimulated cardiac differentiation. Furthermore, co-application of recombinant apoA-I and BMP4 synergistically increased the percentage of beating EBs derived from untransduced D3 ESCs. These together suggests that that pro-cardiogenic apoA-I is mediated via the BMP4-SMAD signaling pathway. Functionally, cardiomyocytes derived from the apoA-I-transduced cells exhibited improved calcium handling properties in both non-caffeine and caffeine-induced calcium transient, suggesting that apoA-I plays a role in enhancing cardiac maturation. This increased cardiac differentiation and maturation has also been observed in human iPSCs, providing further evidence of the beneficial effects of apoA-I in promoting cardiac differentiation. In Conclusion, we present novel experimental evidence that apoA-I enhances cardiac differentiation of ESCs and iPSCs and promotes maturation of the calcium handling property of ESC-derived cardiomyocytes via the BMP4/SMAD signaling pathway

Six-Digit Stroke-based Chinese Input Method

Abstract-During the last three decades, more than one thousand Chinese input methods have been developed. However, people are still looking for better input methods in terms of easy to use, easy to remember, high input speed and small keypad implementation on handheld devices. The well-known strokebased Chinese input method using only five basic stroke types could achieve low learning curve and small numeric keypad implementation but its input speed is limited for complex Chinese characters with a lot of strokes. To tackle this problem, simplified stroke-based Chinese character and phrase coding methods using (3+3) rules are proposed in this paper. The proposed method only uses the first 3 stroke codes and the last 3 stroke codes to represent the first and last radical information of the character for achieving lower average code length and higher hit rate of first character on the candidate list. To further enhance the input speed, a very user-friendly (3+3) phrase coding rule is also proposed for inputting Chinese phrases in terms of 2-character, 3-character and long-character phrases. Three special key assignment designs are developed for practical implementation of the proposed Chinese character and phrase input method using conventional QWERTY keyboard, PC's numeric keypad and mobile phone 12-key keypad. Experimental results have shown that the proposed character coding can achieve lower average code length and higher Hit Rate of First Character as compared with conventional stroke-based method and some well-known Chinese input methods. The proposed coding rules are also very easy to use and remember

Multiple Block-Size Search Algorithm for Fast Block Motion Estimation

Abstract-Although variable block-size motion estimation provides significant video quality and coding efficiency improvement, it requires much higher computational complexity compared with fixed block size motion estimation. The reason is that the current motion estimation algorithms are mainly designed for fixed block size. Current variable block-size motion estimation implementation simply applies these existing motion estimation algorithms independently for different block sizes to find the best block size and the corresponding motion vector. Substantial computation is wasted because distortion data reuse among motion searches of different block sizes is not considered. In this paper, a motion estimation algorithm intrinsically designed for variable block-size video coding is presented. The proposed multiple block-size search (MBSS) algorithm unifies the motion searches for different block sizes into a single searching process instead of independently performing the search for each block size. In this unified search, the suboptimal motion vectors for different block sizes are used to determine the next search steps. Its prediction quality is comparable with that obtained by performing motion search for different block sizes independently while the computational load is substantially reduced. Experimental results show that the prediction quality of MBSS is similar to full search. Block matching, motion estimation, video coding, search pattern, directional search

Human Mental Models of Humanoid Robots

Effective communication between a person and a robot may depend on whether there exists a common ground of understanding between the two. In two experiments modelled after human-human studies we examined how people form a mental model of a robot’s factual knowledge. Participants estimated the robot’s knowledge by extrapolating from their own knowledge and from information about the robot’s origin and language. These results suggest that designers of humanoid robots must attend not only to the social cues that robots emit but also to the information people use to create mental models of a robot.published_or_final_versio