562 research outputs found
Exploration of the Assessment for AVP Algorithm Training in Underground Parking Garages Simulation Scenario
The autonomous valet parking (AVP) functionality in self-driving vehicles is
currently capable of handling most simple parking tasks. However, further
training is necessary to enable the AVP algorithm to adapt to complex scenarios
and complete parking tasks in any given situation. Training algorithms with
real-world data is time-consuming and labour-intensive, and the current state
of constructing simulation environments is predominantly manual. This paper
introduces an approach to automatically generate 3D underground garage
simulation scenarios of varying difficulty levels based on pre-input 2D
underground parking structure plans
PCG-based Static Underground Garage Scenario Generation
Autonomous driving technology has five levels, from L0 to L5. Currently, only
the L2 level (partial automation) can be achieved, and there is a long way to
go before reaching the final level of L5 (full automation). The key to crossing
these levels lies in training the autonomous driving model. However, relying
solely on real-world road data to train the model is far from enough and
consumes a great deal of resources. Although there are already examples of
training autonomous driving models through simulators that simulate real-world
scenarios, these scenarios require complete manual construction. Directly
converting 3D scenes from road network formats will lack a large amount of
detail and cannot be used as training sets. Underground parking garage static
scenario simulation is regarded as a procedural content generation (PCG)
problem. This paper will use the Sarsa algorithm to solve procedural content
generation on underground garage structures
Therapeutically important enzymes with polar substrates or products: characterization by capillary electrophoresis and identification of inhibitors
Enzymes are important drug targets, since they participate in many disease processes and can be inhibited by small drug molecules. In our research projects, a group of therapeutically important enzymes with polar substrates or products has been investigated by means of capillary electrophoresis (CE). The first enzyme we investigated was ecto-5’-nucleotidase (eN), which can catalyze the hydrolysis of the phosphoric acid ester bond of AMP yielding the corresponding nucleoside adenosine and inorganic phosphate. Treatment with eN inhibitors may be a promising novel strategy for cancer therapy, because eN has been found to be overexpressed on many cancer cells, and eN-generated adenosine prevents tumor destruction by inhibiting antitumor immunity. We investigated nucleotide mimetics which consisted of a nucleoside scaffold substituted in the 5’-position with a dipeptide moiety. The compounds were investigated at rat eN using a capillary electrophoresis (CE)-based assay, and potent inhibitors were further investigated at human eN. The test results showed that the inhibitory potency of the compounds appeared to be pH-dependent: when the buffer pH was decreased, the potency of the compounds increased. Since tumor tissues typically show low extracellular pH values, the new inhibitors might act as tumor-selective eN inhibitors without affecting physiologically important functions of eN, such as the production of adenosine in blood vessels, which shows vasodilatory effects. The second enzyme that we investigated was cerebroside sulfotransferase (CST), which catalyzes the transfer of a sulfate group from the co-substrate 3′-phosphoadenosine-5′-phosphosulfate (PAPS) to cerebroside yielding cerebroside sulphate and adenosine-3′,5′-diphosphate (PAP). CST is a promising new therapeutic target for the treatment of metachromatic leukodystrophy (MLD), a devastating genetic disease. In the absence of an effective therapy, MLD leads to early death of the young patients. In the present study we developed a CE-based assay for monitoring the catalytic activity of CST. A low nanomolar limit of detection (LOD = 66.6 nM) was achieved for the enzymatic product PAP by using dynamic pH junction stacking. Our CE method was sensitive, robust and suitable for CST inhibitor screening, Ki value determination, and enzyme kinetic studies. Several reference compounds were tested including cerebrosides, psychosine and Congo Red in order to validate our method. We investigated analogues of the CST substrate cerebroside with this newly developed CE method, in order to study structure-activity relationship (SAR) and to identify and develop novel CST inhibitors. A substrate analogue α-galactosylceramide was identified to be a novel inhibitor, which will be used as a lead structure for developing more potent competitive inhibitors, which are urgently needed for the treatment of MLD. Moreover, SAR information for the CST cerebroside binding site would be highly useful especially since a crystal structure of the CST cerebroside binding site is not available yet. A further group of investigated enzymes were capsule biosynthesis enzymes from Staphylococcus aureus. We characterized the enzymes CapD and CapE of the Staphylococcus aureus serotype 5 biosynthesis cluster, which catalyze the first steps in the synthesis of the soluble capsule precursors UDP-D-FucNAc and UDP-L-FucNAc, respectively. A capillary CE-based method applying micellar electrokinetic chromatography (MEKC) was developed for the functional characterization of the enzymes using dynamic coating of the capillary with polybrene at pH 12.4. The limits of detection for the CapD and CapE products UDP-2-acetamido-2,6-dideoxy-α-D-xylo-hex-4-ulose and UDP-2-acetamido-2,6-dideoxy-β-L-arabino-hex-4-ulose, respectively, were below 1 µM. Using this new, robust and sensitive method we performed kinetic studies for CapD and CapE, and screened a compound library in search for enzyme inhibitors. Several active compounds were identified and characterized. Our studies contribute to a profound understanding of the capsule biosynthesis in pathogenic bacteria. This approach may lead to the identification of novel anti-virulence and antibiotic drugs
Spectral Efficiency and Energy Efficiency Tradeoff in Massive MIMO Downlink Transmission with Statistical CSIT
As a key technology for future wireless networks, massive multiple-input
multiple-output (MIMO) can significantly improve the energy efficiency (EE) and
spectral efficiency (SE), and the performance is highly dependant on the degree
of the available channel state information (CSI). While most existing works on
massive MIMO focused on the case where the instantaneous CSI at the transmitter
(CSIT) is available, it is usually not an easy task to obtain precise
instantaneous CSIT. In this paper, we investigate EE-SE tradeoff in single-cell
massive MIMO downlink transmission with statistical CSIT. To this end, we aim
to optimize the system resource efficiency (RE), which is capable of striking
an EE-SE balance. We first figure out a closed-form solution for the
eigenvectors of the optimal transmit covariance matrices of different user
terminals, which indicates that beam domain is in favor of performing RE
optimal transmission in massive MIMO downlink. Based on this insight, the RE
optimization precoding design is reduced to a real-valued power allocation
problem. Exploiting the techniques of sequential optimization and random matrix
theory, we further propose a low-complexity suboptimal two-layer
water-filling-structured power allocation algorithm. Numerical results
illustrate the effectiveness and near-optimal performance of the proposed
statistical CSI aided RE optimization approach.Comment: Typos corrected. 14 pages, 7 figures. Accepted for publication on
IEEE Transactions on Signal Processing. arXiv admin note: text overlap with
arXiv:2002.0488
A New 95 GHz Methanol Maser Catalog: I. Data
The Purple Mountain Observatory 13.7 m radio telescope has been used to
search for 95 GHz (8--7A) class I methanol masers towards 1020
Bolocam Galactic Plane Survey (BGPS) sources, leading to 213 detections. We
have compared the line width of the methanol and HCO thermal emission in
all of the methanol detections and on that basis we find 205 of the 213
detections are very likely to be masers. This corresponds to an overall
detection rate of 95 GHz methanol masers towards our BGPS sample of 20%. Of the
205 detected masers 144 (70%) are new discoveries. Combining our results with
those of previous 95 GHz methanol masers searches, a total of four hundred and
eighty-one 95 GHz methanol masers are now known, we have compiled a catalog
listing the locations and properties of all known 95 GHz methanol masers.Comment: 18 pages, 7 figures, 8 tables, accepted for publication in ApJ
Layout and Task Aware Instruction Prompt for Zero-shot Document Image Question Answering
The pre-training-fine-tuning paradigm based on layout-aware multimodal
pre-trained models has achieved significant progress on document image question
answering. However, domain pre-training and task fine-tuning for additional
visual, layout, and task modules prevent them from directly utilizing
off-the-shelf instruction-tuning language foundation models, which have
recently shown promising potential in zero-shot learning. Contrary to aligning
language models to the domain of document image question answering, we align
document image question answering to off-the-shell instruction-tuning language
foundation models to utilize their zero-shot capability. Specifically, we
propose layout and task aware instruction prompt called LATIN-Prompt, which
consists of layout-aware document content and task-aware descriptions. The
former recovers the layout information among text segments from OCR tools by
appropriate spaces and line breaks. The latter ensures that the model generates
answers that meet the requirements, especially format requirements, through a
detailed description of task. Experimental results on three benchmarks show
that LATIN-Prompt can improve the zero-shot performance of instruction-tuning
language foundation models on document image question answering and help them
achieve comparable levels to SOTAs based on the pre-training-fine-tuning
paradigm. Quantitative analysis and qualitative analysis demonstrate the
effectiveness of LATIN-Prompt. We provide the code in supplementary and will
release the code to facilitate future research.Comment: Code is available at https://github.com/WenjinW/LATIN-Promp
Altered Ratio of T Follicular Helper Cells to T Follicular Regulatory Cells Correlates with Autoreactive Antibody Response in Simian Immunodeficiency Virus–Infected Rhesus Macaques
Individuals with chronic HIV-1 infection have an increased prevalence of autoreactive Abs. Many of the isolated HIV broadly neutralizing Abs from these individuals are also autoreactive. However, the underlying mechanism(s) that produce these autoreactive broadly neutralizing Abs remains largely unknown. The highly regulated coordination among B cells, T follicular helper (TFH) cells, and T follicular regulatory (TFR) cells in germinal centers (GCs) of peripheral lymphatic tissues (LTs) is essential for defense against pathogens while also restricting autoreactive responses. We hypothesized that an altered ratio of TFH/TFR cells in the GC contributes to the increased prevalence of autoreactive Abs in chronic HIV infection. We tested this hypothesis using a rhesus macaque (RM) SIV model. We measured the frequency of TFH cells, TFR cells, and GC B cells in LTs and anti-dsDNA and anti-phospholipid Abs from Indian RMs, with and without SIV infection. We found that the frequency of anti-dsDNA and antiphospholipid Abs was much higher in chronically infected RMs (83.3% [5/6] and 66.7% [4/6]) than in acutely infected RMs (33.3% [2/6] and 18.6% [1/6]) and uninfected RMs (0% [0/6] and 18.6% [1/6]). The increased ratio of TFH/TFR cells in SIV infection correlated with anti-dsDNA and anti-phospholipid autoreactive Ab levels, whereas the frequency of TFR cells alone did not correlate with the levels of autoreactive Abs. Our results provide direct evidence that the ratio of TFH/TFR cells in LTs is critical for regulating autoreactive Ab production in chronic SIV infection and possibly, by extension, in chronic HIV-1 infection
SIVcpz closely related to the ancestral HIV-1 is less or non-pathogenic to humans in a hu-BLT mouse model
The HIV-1 pandemic is a consequence of the cross-species transmission of simian immunodeficiency virus in wild chimpanzees (SIVcpz) to humans. Our previous study demonstrated SIVcpz strains that are closely related to the ancestral viruses of HIV-1 groups M (SIVcpzMB897) and N (SIVcpzEK505) and two SIVcpz lineages that are not associated with any known HIV-1 infections in humans (SIVcpzMT145 and SIVcpzBF1167), all can readily infect and robustly replicate in the humanized-BLT mouse model of humans. However, the comparative pathogenicity of different SIVcpz strains remains unknown. Herein, we compared the pathogenicity of the above four SIVcpz strains with HIV-1 using humanized-BLT mice. Unexpectedly, we found that all four SIVcpz strains were significantly less pathogenic or non-pathogenic compared to HIV-1, manifesting lower degrees of CD4+ T-cell depletion and immune activation. Transcriptome analyses of CD4+ T cells from hu-BLT mice infected with SIVcpz versus HIV-1 revealed enhanced expression of genes related to cell survival and reduced inflammation/immune activation in SIVcpz-infected mice. Together, our study results demonstrate for the first time that SIVcpz is significantly less or non-pathogenic to human immune cells compared to HIV-1. Our findings lay the groundwork for a possible new understanding of the evolutionary origins of HIV-1, where the initial SIVcpz crossspecies transmission virus may be initially less pathogenic to humans
SIVcpz closely related to the ancestral HIV-1 is less or non-pathogenic to humans in a hu-BLT mouse model
The HIV-1 pandemic is a consequence of the cross-species transmission of simian immunodeficiency virus in wild chimpanzees (SIVcpz) to humans. Our previous study demonstrated SIVcpz strains that are closely related to the ancestral viruses of HIV-1 groups M (SIVcpzMB897) and N (SIVcpzEK505) and two SIVcpz lineages that are not associated with any known HIV-1 infections in humans (SIVcpzMT145 and SIVcpzBF1167), all can readily infect and robustly replicate in the humanized-BLT mouse model of humans. However, the comparative pathogenicity of different SIVcpz strains remains unknown. Herein, we compared the pathogenicity of the above four SIVcpz strains with HIV-1 using humanized-BLT mice. Unexpectedly, we found that all four SIVcpz strains were significantly less pathogenic or non-pathogenic compared to HIV-1, manifesting lower degrees of CD4+ T-cell depletion and immune activation. Transcriptome analyses of CD4+ T cells from hu-BLT mice infected with SIVcpz versus HIV-1 revealed enhanced expression of genes related to cell survival and reduced inflammation/immune activation in SIVcpz-infected mice. Together, our study results demonstrate for the first time that SIVcpz is significantly less or non-pathogenic to human immune cells compared to HIV-1. Our findings lay the groundwork for a possible new understanding of the evolutionary origins of HIV-1, where the initial SIVcpz crossspecies transmission virus may be initially less pathogenic to humans
- …