836 research outputs found
Identification and Analysis of Intermediate Size Noncoding RNAs in the Human Fetal Brain
The involvement of noncoding RNAs (ncRNAs) in the development of the human brain remains largely unknown. Applying a cloning strategy for detection of intermediate size (50–500 nt) ncRNAs (is-ncRNAs) we have identified 82 novel transcripts in human fetal brain tissue. Most of the novel is-ncRNAs are not well conserved in vertebrates, and several transcripts were only found in primates. Northern blot and microarray analysis indicated considerable variation in expression across human fetal brain development stages and fetal tissues for both novel and known is-ncRNAs. Expression of several of the novel is-ncRNAs was conspicuously absent in one or two brain cancer cell lines, and transient overexpression of some transcripts in cancer cells significantly inhibited cell proliferation. Overall, our results suggest that is-ncRNAs play important roles in the development and tumorigenesis of human brain
Generating Synergistic Formulaic Alpha Collections via Reinforcement Learning
In the field of quantitative trading, it is common practice to transform raw
historical stock data into indicative signals for the market trend. Such
signals are called alpha factors. Alphas in formula forms are more
interpretable and thus favored by practitioners concerned with risk. In
practice, a set of formulaic alphas is often used together for better modeling
precision, so we need to find synergistic formulaic alpha sets that work well
together. However, most traditional alpha generators mine alphas one by one
separately, overlooking the fact that the alphas would be combined later. In
this paper, we propose a new alpha-mining framework that prioritizes mining a
synergistic set of alphas, i.e., it directly uses the performance of the
downstream combination model to optimize the alpha generator. Our framework
also leverages the strong exploratory capabilities of reinforcement
learning~(RL) to better explore the vast search space of formulaic alphas. The
contribution to the combination models' performance is assigned to be the
return used in the RL process, driving the alpha generator to find better
alphas that improve upon the current set. Experimental evaluations on
real-world stock market data demonstrate both the effectiveness and the
efficiency of our framework for stock trend forecasting. The investment
simulation results show that our framework is able to achieve higher returns
compared to previous approaches.Comment: Accepted by KDD '23, ADS trac
Design of Wideband Dual-Circularly Polarized Endfire Antenna Array on Gap Waveguide
A wideband dual-circularly polarized (CP) linear antenna array is presented in this paper. Firstly, a dual-CP endfire antenna based on septum polarizer is designed as the element for the array. Secondly, the feeding network is realized by ridge gap waveguide. Then a 1
78 linear antenna array is built up by the elements. The proposed array antenna achieves wide impedance bandwidth of 44.6% with the reflection coefficient below -10 dB, the isolation between ports greater than 15 dB, and a wide 3-dB axial ratio (AR) bandwidth of 46.2%
Adaptive Distribution Calibration for Few-Shot Learning with Hierarchical Optimal Transport
Few-shot classification aims to learn a classifier to recognize unseen
classes during training, where the learned model can easily become over-fitted
based on the biased distribution formed by only a few training examples. A
recent solution to this problem is calibrating the distribution of these few
sample classes by transferring statistics from the base classes with sufficient
examples, where how to decide the transfer weights from base classes to novel
classes is the key. However, principled approaches for learning the transfer
weights have not been carefully studied. To this end, we propose a novel
distribution calibration method by learning the adaptive weight matrix between
novel samples and base classes, which is built upon a hierarchical Optimal
Transport (H-OT) framework. By minimizing the high-level OT distance between
novel samples and base classes, we can view the learned transport plan as the
adaptive weight information for transferring the statistics of base classes.
The learning of the cost function between a base class and novel class in the
high-level OT leads to the introduction of the low-level OT, which considers
the weights of all the data samples in the base class. Experimental results on
standard benchmarks demonstrate that our proposed plug-and-play model
outperforms competing approaches and owns desired cross-domain generalization
ability, indicating the effectiveness of the learned adaptive weights
EGF-stimulation activates the nuclear localization signal of SHP-1
Protein tyrosine phosphatase SHP-1 plays a critical role in the regulation of a variety of intracellular signaling pathways. SHP-1 is predominantly expressed in the cells of hematopoietic origin, and is recognized as a negative regulator of lymphocyte development and activation. SHP-1 consists of two Src homology 2 (SH2) domains and one protein tyrosine phosphatase (PTP) domain followed by a highly basic C-terminal tail containing tyrosyl phosphorylation sites. It is unclear how the C-terminal tail regulates SHP-1 function. We report the examination of the subcellular localization of a variety of truncated or mutated SHP-1 proteins fused with enhanced green fluorescent protein (EGFP) protein at either the N-terminal or the C-terminal end in different cell lines. Our data demonstrate that a nuclear localization signal (NLS) is located in the C-terminal tail of SHP-1 and the signal is primarily defined by three amino-acid residues (KRK) at the C-terminus. This signal is generally blocked in the native protein and can be exposed by fusing EGFP at the appropriate position or by domain truncation. We have also revealed that this NLS of SHP-1 is triggered by epidermal growth factor (EGF) stimulation and mediates translocation of SHP-1 from the cytosol to the nucleus in COS7 cell lines. These results not only demonstrate the importance of the C-terminal tail of SHP-1 in the regulation of nuclear localization, but also provide insights into its role in SHP-1-involved signal transduction pathways. © 2004 Wiley-Liss, Inc
Pharmacokinetic studies and anticancer activity of curcumin-loaded nanostructured lipid carriers
In order to investigate the potential of nanostructured lipid carriers for efficient and targeted delivery of curcumin, the pharmacokinetic parameters of curcumin-loaded nanostructured lipid carriers (Cur-NLC) were evaluated in rats after a single intraperitoneal dose of Cur-NLC. In addition, the anticancer activity of Cur-NLC against human lung adenocarcinoma A549 cells was verified by a cellular uptake study, and a cytotoxicity and apoptosis assay. Bioavailability of Cur-NLC was better than that of native curcumin (p > 0.01), as seen from the area under the plasma concentration-time curve (AUC), maximum plasma concentration (Cmax), mean residence time (MRT) and total plasma clearance (CLz/F). Cur-NLC has a more obvious lung-targeting property in comparison with native curcumin. Cur-NLC showed higher anticancer activity in vitro against A549 cells than native curcumin (IC50 value of 5.66 vs. 9.81 mg L–1, respectively). Meanwhile, Cur-NLC treated A549 cells showed a higher apoptosis rate compared to that of native curcumin. These results indicate that NLC is a promising system for the delivery of curcumin in the treatment of lung adenocarcinoma
Mapping Background Variables With Sequential Patterns in Problem-Solving Environments: An Investigation of United States Adults’ Employment Status in PIAAC
Adult assessments have evolved to keep pace with the changing nature of adult literacy and learning demands. As the importance of information and communication technologies (ICT) continues to grow, measures of ICT literacy skills, digital reading, and problem-solving in technology-rich environments (PSTRE) are increasingly important topics for exploration through computer-based assessment (CBA). This study used process data collected in log files and survey data from the Programme for the International Assessment of Adult Competencies (PIAAC), with a focus on the United States sample, to (a) identify employment-related background variables that significantly related to PSTRE skills and problem-solving behaviors, and (b) extract robust sequences of actions by subgroups categorized by significant variables. We conducted this study in two phases. First, we used regression analyses to select background variables that significantly predict the general PSTRE, literacy, and numeracy skills, as well as the response time and correctness in the example item. Second, we identified typical action sequences by different subgroups using the chi-square feature selection model to explore these sequences and differentiate the subgroups. Based on the malleable factors associated with problem-solving skills, the goal of this study is to provide information for improving competences in adult education for targeted groups
Interplay between multiple charge-density waves and the relationship with superconductivity in PdHoTe
HoTe, a member of the rare-earth tritelluride (Te) family, and
its Pd-intercalated compounds, PdHoTe, where superconductivity (SC)
sets in as the charge-density wave (CDW) transition is suppressed by the
intercalation of a small amount of Pd, are investigated using angle-resolved
photoemission spectroscopy (ARPES) and electrical resistivity. Two
incommensurate CDWs with perpendicular nesting vectors are observed in
HoTe at low temperatures. With a slight Pd intercalation ( = 0.01),
the large CDW gap decreases and the small one increases. The momentum
dependence of the gaps along the inner Fermi surface (FS) evolves from
orthorhombicity to near tetragonality, manifesting the competition between two
CDW orders. At = 0.02, both CDW gaps decreases with the emergence of SC.
Further increasing the content of Pd for = 0.04 will completely suppress
the CDW instabilities and give rise to the maximal SC order. The evolution of
the electronic structures and electron-phonon couplings (EPCs) of the multiple
CDWs upon Pd intercalation are carefully scrutinized. We discuss the interplay
between multiple CDW orders, and the competition between CDW and SC in detail.Comment: 6 pages, 5 figure
TacMMs: Tactile Mobile Manipulators for Warehouse Automation
Multi-robot platforms are playing an increasingly important role in warehouse
automation for efficient goods transport. This paper proposes a novel
customization of a multi-robot system, called Tactile Mobile Manipulators
(TacMMs). Each TacMM integrates a soft optical tactile sensor and a mobile
robot with a load-lifting mechanism, enabling cooperative transportation in
tasks requiring coordinated physical interaction. More specifically, we mount
the TacTip (biomimetic optical tactile sensor) on the Distributed Organisation
and Transport System (DOTS) mobile robot. The tactile information then helps
the mobile robots adjust the relative robot-object pose, thereby increasing the
efficiency of load-lifting tasks. This study compares the performance of using
two TacMMs with tactile perception with traditional vision-based pose
adjustment for load-lifting. The results show that the average success rate of
the TacMMs (66%) is improved over a purely visual-based method (34%), with a
larger improvement when the mass of the load was non-uniformly distributed.
Although this initial study considers two TacMMs, we expect the benefits of
tactile perception to extend to multiple mobile robots. Website:
https://sites.google.com/view/tacmmsComment: 8 pages, accepted in IEEE Robotics and Automation Letters, 19 June
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Quantitative assessment of image motion blur in diffraction images of moving biological cells
Motion blur (MB) presents a significant challenge for obtaining high-contrast image data from biological cells with a polarization diffraction imaging flow cytometry (p-DIFC) method. A new p-DIFC experimental system has been developed to evaluate the MB and its effect on image analysis using a time-delay-integration (TDI) CCD camera. Diffraction images of MCF-7 and K562 cells have been acquired with different speed-mismatch ratios and compared to characterize MB quantitatively. Frequency analysis of the diffraction images shows that the degree of MB can be quantified by bandwidth variations of the diffraction images along the motion direction. The analytical results were confirmed by the p-DIFC image data acquired at different speed-mismatch ratios and used to validate a method of numerical simulation of MB on blur-free diffraction images, which provides a useful tool to examine the blurring effect on diffraction images acquired from the same cell. These results provide insights on the dependence of diffraction image on MB and allow significant improvement on rapid biological cell assay with the p-DIFC method
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